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Nguyen TT, Nguyen NT, Nguyen VV, Nguyen AH, Hoang Tran BD, Vo TK, Truong DT, Doan TLH, Huynh LTN, Tran TN, Ngo HL, Le VH, Nguyen TH. Tailoring hierarchical structures in cellulose carbon aerogels from sugarcane bagasse using different crosslinking agents for enhancing electrochemical desalination capability. Chemosphere 2024; 355:141748. [PMID: 38521109 DOI: 10.1016/j.chemosphere.2024.141748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 03/03/2024] [Accepted: 03/16/2024] [Indexed: 03/25/2024]
Abstract
Sugarcane bagasse is one of the most common Vietnamese agricultural waste, which possesses a large percentage of cellulose, making it an abundant and environmentally friendly source for the fabrication of cellulose carbon aerogel. Herein, waste sugarcane bagasse was used to synthesize cellulose aerogel using different crosslinking agents such as urea, polyvinyl alcohol (PVA) and sodium alginate (SA). The 3D porous network of cellulose aerogels was constructed by intermolecular hydrogen bonding, which was confirmed by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption/desorption. Among the three cellulose aerogel samples, cellulose - SA aerogel (SB-CA-SA) has low density of 0.04 g m-3 and high porosity of 97.38%, leading to high surface area of 497.9 m2 g-1 with 55.67% micropores of activated carbon aerogel (SB-ACCA-SA). The salt adsorption capacity was high (17.87 mg g-1), which can be further enhanced to 31.40 mg g-1 with the addition of CNT. Moreover, the desalination process using the SB-ACCA-SA-CNT electrode was stable even after 50 cycles. The results show the great combination of cellulose from waste sugarcane bagasse with sodium alginate and carbon nanotubes in the fabrication of carbon materials as the CDI-utilized electrodes with high desalination capability and good durability.
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Affiliation(s)
- Thanh Tung Nguyen
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, 700000, Viet Nam
| | - Ngan Tuan Nguyen
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, 700000, Viet Nam; Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Van Vien Nguyen
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Anh Hong Nguyen
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Bao Dung Hoang Tran
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Trung Kien Vo
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Duy Tan Truong
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Tan Le Hoang Doan
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Center for Innovative Materials & Architectures (INOMAR), Ho Chi Minh City, 700000, Viet Nam
| | - Le Thanh Nguyen Huynh
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Thanh Nhut Tran
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Hoang Long Ngo
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, 700000, Viet Nam.
| | - Viet Hai Le
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam
| | - Thai Hoang Nguyen
- Vietnam National University Ho Chi Minh City (VNUHCM), Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Science, Ho Chi Minh City, 700000, Viet Nam; Center for Innovative Materials & Architectures (INOMAR), Ho Chi Minh City, 700000, Viet Nam.
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Nguyen LC, Nguyen NM, Nguyen TN, Vu HH, Khuc TT, La HD, Nguyen NT, Nguyen KV, Nguyen OT, Luu DTM, Doan HTN. 2-year survival estimation for decompensated cirrhosis patients of prognostic scoring systems. Eur Rev Med Pharmacol Sci 2023; 27:10909-10916. [PMID: 38039020 DOI: 10.26355/eurrev_202311_34458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
OBJECTIVE Prognostic models proposed for cirrhotic patients' survival have not been satisfactorily investigated in the Vietnam population, especially in the medium-term period. PATIENTS AND METHODS In this prospective study, we enrolled a total of 904 patients admitted to Hepato-Gastroenterology Center, Bach Mai Hospital from December 2019 to November 2021 and calculated their CP, MELD, MELD-Na score, IMELD, Refit MELD, and Refit MELD-Na after 2-year follow-up to compare their survival prognosis. RESULTS The mean age of the patients was 53.8 ±10.8 years, and males constituted 91%. Compared with the surviving group, deceased patients had statistically significant lower albumin, higher INR, serum bilirubin, and creatinine levels with higher means of all prognostic scores. RefitMELD score had the highest AUC (0.768), followed by MELD (0.766), and the lowest belonged to RefitMELDNa (0.669). CONCLUSIONS In conclusion, deceased patients had significantly higher values of Child-Pugh score and all MELD-based scores than survival. RefitMELD is the most reliable scoring system to predict 2-year mortality in patients with decompensated liver cirrhosis.
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Affiliation(s)
- L C Nguyen
- Gastroenterology and Hepatology Center, Bach Mai Hospital, Giai Phong Road, Ha Noi, Vietnam.
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Velen K, Nguyen TA, Pham CD, Le HT, Nguyen HB, Dao BT, Nguyen TV, Nguyen NT, Nguyen NV, Fox GJ. The effect of medication event reminder monitoring on treatment adherence of TB patients. Int J Tuberc Lung Dis 2023; 27:322-328. [PMID: 37035979 DOI: 10.5588/ijtld.22.0500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2023] Open
Abstract
BACKGROUND: TB control remains a serious public health problem, compounded by poor treatment adherence, which increases the likelihood of onward transmission. We evaluated the effectiveness of medication event reminder monitoring (MERM) upon treatment adherence in a high TB burden setting.METHODS: We conducted an open-label parallel group randomised controlled trial among pulmonary TB adults. Participants were provided with a MERM device to store their medications. In the intervention arm, the devices were set to provide daily medication intake reminders. Primary outcome was the proportion of patient-months in which at least 6/30 doses were missed. Secondary outcomes included 1) the proportion of patient-months in which at least 14/30 doses were missed, and 2) the proportion of doses missed.RESULTS: Of 2,142 patients screened, 798 (37.3%) met the inclusion criteria and 250 participants were enrolled. The mean ratio (MR) for poor adherence between the intervention and control groups was 0.72 (95% CI 0.55-0.86). The intervention was also associated with a reduction in the proportion of patients missing at least 14/30 doses (MR 0.61, 95% CI 0.54-0.68) and the percentage of total doses missed (MR 0.75, 95% CI 0.68-0.80).CONCLUSION: MERM is effective in improving TB treatment adherence in a resource-limited environment.
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Affiliation(s)
- K Velen
- Woolcock Institute of Medical Research, Hanoi, Vietnam, Faculty of Medicine and Health, Central Clinical School, University of Sydney, Sydney, NSW, Australia
| | - T-A Nguyen
- Woolcock Institute of Medical Research, Hanoi, Vietnam, Faculty of Medicine and Health, Central Clinical School, University of Sydney, Sydney, NSW, Australia
| | - C D Pham
- Woolcock Institute of Medical Research, Hanoi, Vietnam
| | - H T Le
- Woolcock Institute of Medical Research, Hanoi, Vietnam
| | | | - B T Dao
- Thanh Hoa Lung Hospital, Thanh Hoa, Vietnam
| | - T V Nguyen
- Thanh Hoa Lung Hospital, Thanh Hoa, Vietnam
| | - N T Nguyen
- Thanh Hoa Lung Hospital, Thanh Hoa, Vietnam
| | | | - G J Fox
- Woolcock Institute of Medical Research, Hanoi, Vietnam, Faculty of Medicine and Health, Central Clinical School, University of Sydney, Sydney, NSW, Australia
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Kondolf GM, Schmitt RJP, Carling PA, Goichot M, Keskinen M, Arias ME, Bizzi S, Castelletti A, Cochrane TA, Darby SE, Kummu M, Minderhoud PSJ, Nguyen D, Nguyen HT, Nguyen NT, Oeurng C, Opperman J, Rubin Z, San DC, Schmeier S, Wild T. Save the Mekong Delta from drowning. Science 2022; 376:583-585. [PMID: 35536906 DOI: 10.1126/science.abm5176] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Policy must address drivers, not just symptoms, of subsidence.
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Affiliation(s)
- G M Kondolf
- Riverlab, Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, CA, USA
| | - R J P Schmitt
- Riverlab, Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, CA, USA
- The Natural Capital Project, Stanford University, Stanford, CA, USA
| | - P A Carling
- School of Geography and Environmental Science, University of Southampton, Southampton, UK
| | - M Goichot
- World Wide Fund for Nature Asia Pacific, Ho Chi Minh City, Vietnam
| | - M Keskinen
- Water and Development Research Group, Aalto University, Espoo, Finland
| | - M E Arias
- Department of Civil and Environmental Engineering, University of South Florida, Tampa, FL, USA
| | - S Bizzi
- Department of Geosciences, University of Padova, Padua, Italy
| | - A Castelletti
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci, Milano, Italy
| | - T A Cochrane
- Department of Civil and Natural Resources Engineering, University of Canterbury, Christchurch, New Zealand
| | - S E Darby
- School of Geography and Environmental Science, University of Southampton, Southampton, UK
| | - M Kummu
- Water and Development Research Group, Aalto University, Espoo, Finland
| | - P S J Minderhoud
- Soil Geography and Landscape group, Wageningen University, Netherlands
- Department of Civil, Environmental and Architectural Engineering, University of Padova, Padova, Italy
- Subsurface and Groundwater Systems Unit, Deltares Research Institute, Utrecht, Netherlands
| | - D Nguyen
- Laboratory for Hydraulics Saint-Venant, Université PARIS-EST, Chatou, France
| | | | - N T Nguyen
- University of Science, Vietnam National University, Ho Chi Minh City, Vietnam
| | - C Oeurng
- Riverlab, Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, CA, USA
- Institute of Technology of Cambodia, Phnom Penh, Cambodia
| | - J Opperman
- Global Science, World Wildlife Fund, Washington, DC, USA
| | - Z Rubin
- Riverlab, Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, CA, USA
- Balance Hydrologics, Berkeley, CA, USA
| | - D C San
- Southern Institute of Water Resources Research, Ho Chi Minh City, Vietnam
| | - S Schmeier
- Water Governance Department, IHE Delft Institute for Water Education, Delft, Netherlands
| | - T Wild
- University of Maryland, College Park, MD, USA
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Shelley D, Cleland CM, Nguyen T, Van Devanter N, Siman N, Van M H, Nguyen NT. Effectiveness of a multicomponent strategy for implementing guidelines for treating tobacco use in Vietnam Commune Health Centers. Nicotine Tob Res 2021; 24:196-203. [PMID: 34543422 DOI: 10.1093/ntr/ntab189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/15/2021] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Strategies are needed to increase implementation of evidence-based tobacco dependence treatment (TDT) in health care systems in low-and middle-income countries (LMICs). METHODS We conducted a two-arm cluster randomized controlled trial to compare the effectiveness of two strategies for implementing TDT guidelines in community health centers (n=26) in Vietnam. Arm 1 included training and a tool kit (e.g., reminder system) to promote and support delivery of the 4As (Ask about tobacco use, Advise to quit, Assess readiness, Assist with brief counseling) (Arm 1). Arm 2 included Arm 1 components plus a system to refer smokers to a community health worker (CHW) for more intensive counseling (4As+R). Provider surveys were conducted at baseline, six- and 12-months to assess the hypothesized effect of the strategies on provider and organizational-level factors. The primary outcome was provider adoption of the 4As. RESULTS Adoption of the 4As increased significantly across both study arms (all p<.001). Perceived organizational priority for TDT, compatibility with current workflow, and provider attitudes, norms and self-efficacy related to TDT also improved significantly across both arms. In Arm 2 sites, 41% of smokers were referred to a CHW for additional counseling. CONCLUSION The study demonstrated the effectiveness of a multicomponent and multilevel strategy (i.e., provider and system) for implementing evidence-based TDT in the Vietnam public health system. Combining provider-delivered brief counseling with opportunities for more in-depth counseling offered by a trained CHW may optimize outcomes and offers a potentially scalable model for increasing access to TDT in health care systems like Vietnam. IMPLICATIONS Improving implementation of evidence-based tobacco dependence treatment (TDT) guidelines is a necessary step towards reducing the growing burden of non-communicable disease (NCDs) and premature death in LMICs. The findings provide new evidence on the effectiveness of multilevel strategies for adapting and implementing TDT into routine care in Vietnam, and offers a potentially scalable model for meeting FCTC Article 14 goals in other LMICs with comparable public health systems. The study also demonstrates that combining provider-delivered brief counseling with referral to a community health worker for more in-depth counseling and support can optimize access to evidence-based treatment for tobacco use.
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Affiliation(s)
- D Shelley
- New York University School of Global Public Health, New York, NY
| | - C M Cleland
- New York University Grossman School of Medicine, Department of Population Health, NY
| | - T Nguyen
- Institute of Social and Medical Studies, My Dinh Ward, South Tu Liem District, Ha Noi, Vietnam
| | - N Van Devanter
- Rory Myers College of Nursing, New York University, New York, NY
| | - N Siman
- New York University Grossman School of Medicine, Department of Population Health, NY
| | - Hoang Van M
- Minh Hoang Van, MD, Hanoi University of Public Health, Duc Thang Ward, North Tu Liem district, Hanoi, Vietnam
| | - N T Nguyen
- Institute of Social and Medical Studies, My Dinh Ward, South Tu Liem District, Ha Noi, Vietnam
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Nguyen NT, Liu M, Katayama H, Takemura T, Kasuga I. Association of the colistin resistance gene mcr-1 with faecal pollution in water environments in Hanoi, Vietnam. Lett Appl Microbiol 2020; 72:275-282. [PMID: 33099779 DOI: 10.1111/lam.13421] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/30/2020] [Accepted: 10/20/2020] [Indexed: 11/29/2022]
Abstract
Colistin is one of the antibiotics of last resort for human health. However, the dissemination of the plasmid-mediated colistin resistance gene mcr-1 is of great concern globally. In the One Health framework, the environment is an important component for managing antimicrobial resistance. However, little information is available concerning the prevalence of mcr-1 in water environments. We aimed to reveal the prevalence of mcr-1 in different water environments in Hanoi, Vietnam. Quantitative PCR was applied to detect mcr-1 in four urban drainages receiving untreated domestic wastewater, three rivers, five lakes and two groundwater samples. Urban drainages contained higher concentrations of mcr-1, suggesting that urban residents carry the gene. The class 1 integron-integrase gene was identified as a good surrogate of antibiotic resistance genes including mcr-1. A significant correlation was found between the levels of mcr-1 and the human-specific cross-assembly phage, which is an indicator of human faecal pollution. These results indicated that the primary source of mcr-1 in urban water environments is human faeces, which is consistent with the fact that most domestic wastewater is untreated in Hanoi. The control of untreated wastewater is critical for alleviating the spread of mcr-1 in water environments in Vietnam.
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Affiliation(s)
- N T Nguyen
- Vietnam Research Station, Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine, Nagasaki University, Hanoi, Vietnam.,Master's Program in Environmental Engineering, VNU Vietnam Japan University, Hanoi, Vietnam
| | - M Liu
- Department of Urban Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - H Katayama
- Department of Urban Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - T Takemura
- Vietnam Research Station, Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine, Nagasaki University, Hanoi, Vietnam
| | - I Kasuga
- Master's Program in Environmental Engineering, VNU Vietnam Japan University, Hanoi, Vietnam.,Department of Urban Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
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Nguyen NT, Hirata M, Tanihara F, Sato Y, Namula Z, Le QA, Wittayarat M, Fahrudin M, Otti T. In vitro Development of Zona Pellucida-free Porcine Zygotes Cultured Individually after Vitrification. Cryo Letters 2020; 41:86-91. [PMID: 33988658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
BACKGROUND Cryopreservation of zona pellucida (ZP)-free embryos provides more options for somatic cell nuclear transfer, particularly during handmade cloning. OBJECTIVE This study investigated whether the removal of the ZP affects the development of porcine zygotes after vitrification and warming. MATERIALS AND METHODS We determined the appropriate volume of the corresponding medium for the individual culture of ZP-intact and -free embryos and evaluated the protection effect of ZP during cryopreservation on the resulting development of the vitrified-warmed zygotes. RESULTS The volume of culture medium influenced the development of ZP-intact zygotes, and a volume of 15 µL was most suitable for their development. However, the volume of culture medium did not modify the development of ZP-free zygotes. The removal of the ZP before vitrification did not adversely affect embryonic development or quality of the resulting blastocysts. CONCLUSION Our results suggest that the removal of the ZP does not cause detrimental effects to the development of vitrified-warmed zygotes.
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Affiliation(s)
| | - M Hirata
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan.
| | - F Tanihara
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Y Sato
- School of Biological Science, Tokai University, Sapporo, Japan
| | - Z Namula
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan; College of Agricultural Science, Guangdong Ocean University, Guangdong, China
| | - Q A Le
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - M Wittayarat
- Faculty of Veterinary Science, Prince of Songkla University, Songkhla, Thailand
| | - M Fahrudin
- Faculty of Veterinary Science, Bogor Agricultural University, Indonesia
| | - T Otti
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
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de Wijs LEM, Nguyen NT, Kunkeler ACM, Nijsten T, Damman J, Hijnen DJ. Clinical and histopathological characterization of paradoxical head and neck erythema in patients with atopic dermatitis treated with dupilumab: a case series. Br J Dermatol 2019; 183:745-749. [PMID: 31749159 PMCID: PMC7586932 DOI: 10.1111/bjd.18730] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2019] [Indexed: 12/29/2022]
Abstract
Dupilumab is the first biologic registered for the treatment of atopic dermatitis (AD). We report on seven patients with AD presenting with a paradoxical head and neck erythema that appeared 10-39 weeks after the start of dupilumab treatment. The patients presented with a relatively sharply demarcated, patchy erythema in the head and neck area that showed no or less scaling compared with their usual eczema. Only one patient experienced symptoms of itch and burning, although this was notably different from his pre-existent facial AD. Except for a notable 'red face', eczema on other body parts had greatly improved in six of the seven patients, with a mean numerical rating scale for treatment satisfaction of 9 out of 10 at the time of biopsy. Treatment of the erythema with topical and systemic drugs was unsuccessful. Despite the presence of this erythema, none of our patients discontinued dupilumab treatment. Lesional skin biopsies showed an increased number of ectatic capillaries, and a perivascular lymphohistiocytic infiltration in all patients. In addition, epidermal hyperplasia with elongation of the rete ridges was observed in four patients, resembling a psoriasiform dermatitis. Additional immunohistochemical stainings revealed increased numbers of plasma cells, histiocytes and T lymphocytes. Interestingly, spongiosis was largely absent in all biopsies. We report on patients with AD treated with dupilumab developing a paradoxical erythema in a head and neck distribution. Both clinically and histopathologically we found a heterogeneous response, which was most suggestive of a drug-induced skin reaction.
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Affiliation(s)
- L E M de Wijs
- Department of Dermatology, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - N T Nguyen
- Department of Dermatology, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - A C M Kunkeler
- Department of Dermatology, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - T Nijsten
- Department of Dermatology, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - J Damman
- Department of Pathology, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - D J Hijnen
- Department of Dermatology, Erasmus MC University Medical Center, Rotterdam, the Netherlands
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Velazquez AI, Nguyen NT, Rodriguez-Bonilla C, Shao T. Abstract P5-15-03: Imaging is not indicated in staging of asymptomatic patients with early breast cancer – Are we following current recommendations? Cancer Res 2019. [DOI: 10.1158/1538-7445.sabcs18-p5-15-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Breast cancer is the most common malignancy in women with estimated care costs of $20.50 billion/year by 2020. In 2012, ASCO released the Choosing Wisely Initiative which recommended against the use of routine staging imaging in patients with newly diagnosed early stage breast cancer. We examined physician's adherence rate and factors associated with non-adherence to current guidelines in patients with early stage breast cencer treated within a large urban health care system.
We identified all women with stage I-II breast cancer diagnosed between January 1, 2014 and December 31, 2015 from the Cancer Registry of the Mount Sinai Health System. Patients with history of prior malignancy or symptom-triggered imaging were excluded. Demographic, clinical and treatment related factors were collected. Medical records were reviewed to identify patients who had routine staging scans. Data of initial and follow-up imaging over 1-year period were collected. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from logistic regression models.
Among 917 breast cancer patients, the median age at diagnosis was 59 years (range 26-98). One hundred seventy one patients (18.6%) had routine staging imaging with a mean number of initial scans of 1.48. Eighty-two patients (48%) had at least 1 subsequent scan in the 1-year follow up (range 1-4 scans/year). PET/CT was the most frequent modality (49%), followed by CT scan (33%). The medical oncologist was the ordering provider in 50.3% of the cases and surgical oncologist in 43.2%. Routine staging scans identified no cases of metastatic disease. False-positive findings were identified in 49.7% and incidental findings in 9.3% of cases. Total cost of imaging in this group was $3990/patient. Young age (<50 years old), tumor size >2cm, positive lymph nodes, and triple negative disease were associated with presence of routine staging scans on univariate and multivariate analysis (Table 1).
Our study highlights the prevalence of unnecessary staging scans in up to 18.6% of patients with early stage I-II breast cancer. Routine imaging resulted in increased radiation exposure, multiple subsequent imaging, and increased economical burden particularly for those of young age, T2 tumors, positive lymph nodes, and triple negative disease. Further educational efforts are needed to avoid unnecessary scans in patients with early stage breast cancer and improve high-value practices among medical and surgical oncologists.
Factors associated with routine staging scans in early breast cancer OR95% CIp-value Univariate Analysis: Age < 501.691.17-2.420.005T2 tumors4.353.01-6.28<0.0001Positive lymph nodes5.073.43-7.51<0.0001Triple negative disease2.941.86-4.63<0.0001 Multivariate Analysis: Age < 501.571.03-2.390.037T2 tumors3.472.34 -5.17<0.0001Positive lymph nodes4.042.64-6.18<0.0001Triple negative disease2.991.76-5.05<0.0001
Citation Format: Velazquez AI, Nguyen NT, Rodriguez-Bonilla C, Shao T. Imaging is not indicated in staging of asymptomatic patients with early breast cancer – Are we following current recommendations? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-15-03.
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Affiliation(s)
- AI Velazquez
- Icahn School of Medicine at Mount Sinai Beth Israel, New York, NY
| | - NT Nguyen
- Icahn School of Medicine at Mount Sinai Beth Israel, New York, NY
| | | | - T Shao
- Icahn School of Medicine at Mount Sinai Beth Israel, New York, NY
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Van Nguyen D, Vidal C, Chi HC, NTQ D, Nguyen NN, HTT N, Nguyen NT, TTL T, Fulton R, Li J, Fernando SL. P72: GENE PROFILING STUDIES DEMONSTRATE THE ROLE OF INNATE IMMUNE RESPONSES IN ALLOPURINOL-INDUCED SEVERE CUTANEOUS ADVERSE REACTIONS. Intern Med J 2017. [DOI: 10.1111/imj.72_13578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D Van Nguyen
- Sydney Medical School-Northern; University of Sydney; Sydney Australia
- ImmunoRheumatology Laboratory; New South Wales Sydney Australia
- Department of Allergy and Clinical Immunology; Hanoi Medical University; Hanoi Vietnam
| | - C Vidal
- ImmunoRheumatology Laboratory; New South Wales Sydney Australia
| | - HC Chi
- Centre of Allergology and Clinical Immunology, Bach Mai Hospital; Hanoi Vietnam
| | - Do NTQ
- Department of Immunology and Molecular Biology, National Institute of Hygiene and Epidemiology; Hanoi Vietnam
| | - NN Nguyen
- Centre of Allergology and Clinical Immunology, Bach Mai Hospital; Hanoi Vietnam
| | - Nguyen HTT
- Department of Allergy and Clinical Immunology; Hanoi Medical University; Hanoi Vietnam
| | | | - Tran TTL
- Hanoi Heart Hospital; Hanoi Vietnam
| | - R Fulton
- ImmunoRheumatology Laboratory; New South Wales Sydney Australia
| | - J Li
- ImmunoRheumatology Laboratory; New South Wales Sydney Australia
| | - SL Fernando
- Sydney Medical School-Northern; University of Sydney; Sydney Australia
- ImmunoRheumatology Laboratory; New South Wales Sydney Australia
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Nguyen HV, Caruso D, Lebrun M, Nguyen NT, Trinh TT, Meile JC, Chu-Ky S, Sarter S. Antibacterial activity of Litsea cubeba (Lauraceae, May Chang) and its effects on the biological response of common carp Cyprinus carpio challenged with Aeromonas hydrophila. J Appl Microbiol 2016; 121:341-51. [PMID: 27124660 DOI: 10.1111/jam.13160] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/17/2016] [Accepted: 04/21/2016] [Indexed: 12/17/2022]
Abstract
AIMS The aims of this study were to characterize the antibacterial activity and the chemotype of Litsea cubeba leaf essential oil (EO) harvested in North Vietnam and to investigate the biological effects induced by the leaf powder on growth, nonspecific immunity and survival of common carp (Cyprinus carpio) challenged with Aeromonas hydrophila. METHODS AND RESULTS The EO showed the prevalence of linalool (95%, n = 5). It was bactericidal against the majority of tested strains, with minimum inhibitory concentrations ranging from 0·72 to 2·89 mg ml(-1) (Aer. hydrophila, Edwarsiella tarda, Vibrio furnissii, Vibrio parahaemolyticus, Streptococcus garvieae, Escherichia coli, Salmonella Typhimurium). The fish was fed with 0 (control), 2, 4 and 8% leaf powder supplementation diets for 21 days. Nonspecific immunity parameters (lysozyme, haemolytic and bactericidal activities of plasma) were assessed 21 days after feeding period and before the experimental infection. Weight gain, specific growth rate and feed conversion ratio were improved by supplementation of L. cubeba in a dose-related manner, and a significant difference appeared at the highest dose (8%) when compared to the control. The increase in plasma lysozyme was significant for all the treated groups. Haemolysis activity was higher for the groups fed with 4 and 8% plant powder. Antibacterial activity increased significantly for the 8% dose only. CONCLUSIONS Litsea cubeba leaf powder increased nonspecific immunity of carps in dose-related manner. After infection with Aer. hydrophila, survivals of fish fed with 4 and 8% L. cubeba doses were significantly higher than those fed with 2% dose and the control. SIGNIFICANCE AND IMPACT OF THE STUDY A range of 4-8% L. cubeba leaf powder supplementation diet (from specific linalool-rich chemotype) can be used in aquaculture to reduce antibiotic burden and impacts of diseases caused by Aer. hydrophila.
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Affiliation(s)
- H V Nguyen
- Hanoi University of Science and Technology, Hanoi, Vietnam.,UMR Qualisud, CIRAD, Montpellier, France.,UMR Qualisud, CIRAD, Hanoi, Vietnam
| | - D Caruso
- ISEM UMR 226, IRD, Montpellier, France
| | - M Lebrun
- UMR Qualisud, CIRAD, Montpellier, France
| | - N T Nguyen
- Vietnam National University of Agriculture, Hanoi, Vietnam
| | - T T Trinh
- Vietnam National University of Agriculture, Hanoi, Vietnam
| | - J-C Meile
- UMR Qualisud, CIRAD, Montpellier, France
| | - S Chu-Ky
- Hanoi University of Science and Technology, Hanoi, Vietnam
| | - S Sarter
- UMR Qualisud, CIRAD, Montpellier, France.,UMR Qualisud, CIRAD, Hanoi, Vietnam
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12
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Nguyen NT, Vafin RR, Rzhanov IV, Kolpakov AI, Gataullin IG, Tyulkin SV, Sinyagina MN, Grigoryeva TV, Ilinskaya ON. [MOLECULAR-GENETIC ANALYSIS OF MICROORGANISMS WITH INTRAEPITHELIAL INVASION ISOLATED FROM PATIENTS WITH COLORECTAL CANCER]. Mol Gen Mikrobiol Virusol 2016; 34:13-18. [PMID: 27183716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The facultative aerobic bacteria isolated from the mucosa of rectum in patients with colorectal cancer in the zone of malignant tumor and neighboring normal mucosa was studied using molecular-genetic methods. The species attribution of bacteria was implemented using the cultural-morphological analysis and sequencing of the 16S rRNA locus. The microorganisms with the intraepithelial invasion to rectal mucosa isolated were identified as representatives of the adherent-invasive (AIEC) subgroup of Escherichia coli and species Klebsiella pneumonia. The molecular analysis by genetic determinants controlling adhesive, hemolytic, and toxigenic activity revealed that some bacterial isolates were able to produce toxins with potential cancerogenic activity (e.g., colibactin and cytotoxic necrotic factor I). Certain bacterial species isolated from malignant and normal rectum epithelium of the same patient demonstrated no difference between analyzed factors of toxigenicity.
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Yuan D, Zhang J, Yan S, Pan C, Alici G, Nguyen NT, Li WH. Dean-flow-coupled elasto-inertial three-dimensional particle focusing under viscoelastic flow in a straight channel with asymmetrical expansion-contraction cavity arrays. Biomicrofluidics 2015; 9:044108. [PMID: 26339309 PMCID: PMC4522007 DOI: 10.1063/1.4927494] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 07/14/2015] [Indexed: 05/08/2023]
Abstract
In this paper, 3D particle focusing in a straight channel with asymmetrical expansion-contraction cavity arrays (ECCA channel) is achieved by exploiting the dean-flow-coupled elasto-inertial effects. First, the mechanism of particle focusing in both Newtonian and non-Newtonian fluids was introduced. Then particle focusing was demonstrated experimentally in this channel with Newtonian and non-Newtonian fluids using three different sized particles (3.2 μm, 4.8 μm, and 13 μm), respectively. Also, the effects of dean flow (or secondary flow) induced by expansion-contraction cavity arrays were highlighted by comparing the particle distributions in a single straight rectangular channel with that in the ECCA channel. Finally, the influences of flow rates and distances from the inlet on focusing performance in the ECCA channel were studied. The results show that in the ECCA channel particles are focused on the cavity side in Newtonian fluid due to the synthesis effects of inertial and dean-drag force, whereas the particles are focused on the opposite cavity side in non-Newtonian fluid due to the addition of viscoelastic force. Compared with the focusing performance in Newtonian fluid, the particles are more easily and better focused in non-Newtonian fluid. Besides, the Dean flow in visco-elastic fluid in the ECCA channel improves the particle focusing performance compared with that in a straight channel. A further advantage is three-dimensional (3D) particle focusing that in non-Newtonian fluid is realized according to the lateral side view of the channel while only two-dimensional (2D) particle focusing can be achieved in Newtonian fluid. Conclusively, this novel Dean-flow-coupled elasto-inertial microfluidic device could offer a continuous, sheathless, and high throughput (>10 000 s(-1)) 3D focusing performance, which may be valuable in various applications from high speed flow cytometry to cell counting, sorting, and analysis.
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Affiliation(s)
- D Yuan
- School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong , Wollongong, New South Wales 2522, Australia
| | - J Zhang
- School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong , Wollongong, New South Wales 2522, Australia
| | - S Yan
- School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong , Wollongong, New South Wales 2522, Australia
| | - C Pan
- School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong , Wollongong, New South Wales 2522, Australia
| | - G Alici
- School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong , Wollongong, New South Wales 2522, Australia
| | - N T Nguyen
- Queensland Micro and Nanotechnology Centre, Griffith University , Brisbane, Queensland 4111, Australia
| | - W H Li
- School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong , Wollongong, New South Wales 2522, Australia
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14
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Esters M, Alemayehu MB, Jones Z, Nguyen NT, Anderson MD, Grosse C, Fischer SF, Johnson DC. Synthesis of inorganic structural isomers by diffusion-constrained self-assembly of designed precursors: a novel type of isomerism. Angew Chem Int Ed Engl 2014; 54:1130-4. [PMID: 25522188 DOI: 10.1002/anie.201409714] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Indexed: 11/12/2022]
Abstract
The structure of precursors is used to control the formation of six possible structural isomers that contain four structural units of PbSe and four structural units of NbSe2: [(PbSe)1.14]4[NbSe2]4, [(PbSe)1.14]3[NbSe2]3[(PbSe)1.14]1[NbSe2]1, [(PbSe)1.14]3[NbSe2]2[(PbSe)1.14]1[NbSe2]2, [(PbSe)1.14]2[NbSe2]3[(PbSe)1.14]2[NbSe2]1, [(PbSe)1.14]2[NbSe2]2[(PbSe)1.14]1[NbSe2]1[(PbSe)1.14]1[NbSe2]1, [(PbSe)1.14]2[NbSe2]1[(PbSe)1.14]1[NbSe2]2[(PbSe)1.14]1[NbSe2]1. The electrical properties of these compounds vary with the nanoarchitecture. For each pair of constituents, over 20,000 new compounds, each with a specific nanoarchitecture, are possible with the number of structural units equal to 10 or less. This provides opportunities to systematically correlate structure with properties and hence optimize performance.
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Affiliation(s)
- Marco Esters
- Department of Chemistry, University of Oregon, Eugene, OR 97403 (USA) http://pages.uoregon.edu/grnchem/davejohnson.html; Materials Science Institute, University of Oregon, Eugene, OR 97403-1253 (USA)
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15
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Zlotea C, Morfin F, Nguyen TS, Nguyen NT, Nelayah J, Ricolleau C, Latroche M, Piccolo L. Nanoalloying bulk-immiscible iridium and palladium inhibits hydride formation and promotes catalytic performances. Nanoscale 2014; 6:9955-9959. [PMID: 25059734 DOI: 10.1039/c4nr02836h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The hydrogen sorption properties of oxide-supported Ir-Pd nanoalloys have been determined for the first time, and correlated with their catalytic behavior. The addition of Ir to Pd suppresses hydride formation and leads to improved catalytic performances with respect to pure metals in the preferential oxidation of CO in H2 excess (PROX).
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Affiliation(s)
- C Zlotea
- ICMPE, Institut de Chimie et des Matériaux de Paris-Est, UMR 7182 CNRS & Université Paris Est Créteil, 2-8 rue Henri Dunant, 94320 Thiais, France
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16
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Kanaya E, Sakabe T, Nguyen NT, Koikeda S, Koga Y, Takano K, Kanaya S. Cloning of the RNase H genes from a metagenomic DNA library: identification of a new type 1 RNase H without a typical active-site motif. J Appl Microbiol 2011; 109:974-83. [PMID: 20408915 DOI: 10.1111/j.1365-2672.2010.04724.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS The study aimed to combine a metagenomics approach with complementary genetics to identify novel bacterial genes with orthologous functions, with the identification of novel RNase H genes as a test case. METHODS AND RESULTS A metagenomic DNA library was prepared from leaf-and-branch compost and used to screen for the RNase H genes by their abilities to complement the temperature-sensitive growth phenotype of the rnhA mutant Escherichia coli strain MIC3001. Determination of the nucleotide sequences of the cloned DNA fragments allowed us to identify 12 different genes encoding type 1 RNases H. Eleven of them encode novel RNases H, which show 40-72% amino acid sequence identities to those available from database. One of them lacks a typical DEDD/E active-site motif, which is almost fully conserved in various RNases H. CONCLUSIONS Functional screening of environmental DNA without cultivation of microbes is a useful procedure to isolate novel RNase H genes. SIGNIFICANCE AND IMPACT OF THE STUDY One of the identified RNase H genes had no sequence similarity to a previously assumed conserved motif, suggesting multiple catalytic mechanisms exist. This test case illustrates that metagenomics combined with complementary genetics can identify novel genes that are orthologous without sequence similarity to those from cultivated bacteria.
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Affiliation(s)
- E Kanaya
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Osaka, Japan.
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17
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Haiwang L, Nguyen NT, Wong TN, Ng SL. Microfluidic on-chip fluorescence-activated interface control system. Biomicrofluidics 2010; 4:44109. [PMID: 21173886 PMCID: PMC3003716 DOI: 10.1063/1.3516036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 10/18/2010] [Indexed: 05/25/2023]
Abstract
A microfluidic dynamic fluorescence-activated interface control system was developed for lab-on-a-chip applications. The system consists of a straight rectangular microchannel, a fluorescence excitation source, a detection sensor, a signal conversion circuit, and a high-voltage feedback system. Aqueous NaCl as conducting fluid and aqueous glycerol as nonconducting fluid were introduced to flow side by side into the straight rectangular microchannel. Fluorescent dye was added to the aqueous NaCl to work as a signal representing the interface position. Automatic control of the liquid interface was achieved by controlling the electroosmotic effect that exists only in the conducting fluid using a high-voltage feedback system. A LABVIEW program was developed to control the output of high-voltage power supply according the actual interface position, and then the interface position is modified as the output of high-voltage power supply. At last, the interface can be moved to the desired position automatically using this feedback system. The results show that the system presented in this paper can control an arbitrary interface location in real time. The effects of viscosity ratio, flow rates, and polarity of electric field were discussed. This technique can be extended to switch the sample flow and droplets automatically.
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18
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Lam YC, Gan HY, Nguyen NT, Lie H. Micromixer based on viscoelastic flow instability at low Reynolds number. Biomicrofluidics 2009; 3:14106. [PMID: 19693399 PMCID: PMC2717585 DOI: 10.1063/1.3108462] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Accepted: 03/05/2009] [Indexed: 05/11/2023]
Abstract
We exploited the viscoelasticity of biocompatible dilute polymeric solutions, namely, dilute poly(ethylene oxide) solutions, to significantly enhance mixing in microfluidic devices at a very small Reynolds number, i.e., Re approximately 0.023, but large Peclet and elasticity numbers. With an abrupt contraction microgeometry (8:1 contraction ratio), two different dilute poly(ethylene oxide) solutions were successfully mixed with a short flow length at a relatively fast mixing time of <10 mus. Microparticle image velocimetry was employed in our investigations to characterize the flow fields. The increase in velocity fluctuation with an increase in flow rate and Deborah number indicates the increase in viscoelastic flow instability. Mixing efficiency was characterized by fluorescent concentration measurements. Our results showed that enhanced mixing can be achieved through viscoelastic flow instability under situations where molecular-diffusion and inertia effects are negligible. This approach bypasses the laminar flow limitation, usually associated with a low Reynolds number, which is not conducive to mixing.
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Affiliation(s)
- Y C Lam
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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19
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Irvine Medical Center, 333 City Building West, Suite 850, Orange, CA 92868, USA.
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20
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Abstract
In the past few years, much attention has been paid to the development of miniaturized polymerase chain reaction (PCR) devices. After a continuous flow (CF) PCR chip was introduced, several CFPCR systems employing various pumping mechanisms were reported. However, the use of pumps increases cost and imposes a high requirement on microchip bonding integrity due to the application of high pressure. Other significant limitations of CFPCR devices include the large footprint of the microchip and the fixed cycle number which is dictated by the channel layout. In this paper, we present a novel circular close-loop ferrofluid driven microchip for rapid PCR. A small ferrofluid plug, containing sub-domain magnetic particles in a liquid carrier, is driven by an external magnet along the circular microchannel, which in turn propels the PCR mixture through three temperature zones. Amplification of a 500 bp lambda DNA fragment has been demonstrated on the polymethyl methacrylate (PMMA) PCR microchip fabricated by CO(2) laser ablation and bonded by a low pressure, high temperature technique. Successful PCR was achieved in less than 4 min. Effects of cycle number and cycle time on PCR products were investigated. Using a magnet as the actuator eliminates the need for expensive pumps and provides advantages of low cost, small power consumption, low requirement on bonding strength and flexible number of PCR cycles. Furthermore, the microchip has a much simpler design and smaller footprint compared to the rectangular serpentine CFPCR devices. To demonstrate its application in forensics, a 16-loci short tandem repeat (STR) sample was successfully amplified using the PCR microchip.
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Affiliation(s)
- Y Sun
- National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616
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21
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Huang XY, Nguyen NT, Jiao ZJ. Nonlinear standing waves in a resonator with feedback control. J Acoust Soc Am 2007; 122:38-41. [PMID: 17614462 DOI: 10.1121/1.2735808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
An experimental study is presented to demonstrate that nonlinear effect on standing waves in a resonator can be reduced by a feedback loop responding to the second harmonic. The resonator was a cylindrical tube sealed at one end and driven by a horn driver unit at another end. The feedback control loop consisted of a pressure sensor, a frequency filter, a phase shifter, and an actuator. The results show that the waveform distortions can be eliminated and large amplitude sinusoidal pressure oscillations are obtained. A simple model is proposed for a qualitative discussion on the control mechanism, which shows that the feedback loop alters the imaginary part of the complex mode frequency so as to suppress (or enhance) the second harmonic.
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Affiliation(s)
- X Y Huang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore.
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22
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Luo C, Huang XY, Nguyen NT. Generation of shock-free pressure waves in shaped resonators by boundary driving. J Acoust Soc Am 2007; 121:2515-21. [PMID: 17550150 DOI: 10.1121/1.2713716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Investigation of high amplitude pressure oscillations generated by boundary driving in shaped resonators has been carried out both theoretically and experimentally. In the theoretical modeling, the acoustic resonance in an axisymmetric resonator is studied by the Galerkin method. The resonator is exponentially expanded and the boundary driving is provided by a piston at one end. The pressure wave forms, amplitudes, resonance frequencies, and ratio of pressures at the two ends of the resonator are calculated for various expansion flare constants and driving strengths. These results are partially compared with those generated by shaking the resonator. They are also verified in the experiment, in which an exponentially expanded resonator is connected to a speaker box functioning as the piston. The experiment is further extended to a horn-shaped resonator with a rectangular cross section. The boundary driving in this case is generated by a circular piezoelectric disk, which forms one sidewall of the resonator cavity. The characteristics of axisymmetric resonators, such as the resonance frequency and amplitude ratio of pressures at the two ends, are observed in this low aspect ratio rectangular resonator with the sidewall driving.
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Affiliation(s)
- C Luo
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
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Kanai S, Ohkura K, Adu-Gyamfi JJ, Mohapatra PK, Nguyen NT, Saneoka H, Fujita K. Depression of sink activity precedes the inhibition of biomass production in tomato plants subjected to potassium deficiency stress. J Exp Bot 2007; 58:2917-28. [PMID: 17630289 DOI: 10.1093/jxb/erm149] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Tomato [Solanum lycopersicum (formerly Lycopersicon esculentum) L. cv. Momotarou] plants were grown hydroponically inside the greenhouse of Hiroshima University, Japan. The adverse effects of potassium (K) deficiency stress on the source-sink relationship during the early reproductive period was examined by withdrawing K from the rooting medium for a period of 21 d. Fruits and stem were the major sink organs for the carbon assimilates from the source. A simple non-destructive micro-morphometric technique was used to measure growth of these organs. The effect of K deficiency was studied on the apparent photosynthesis (source activity), leaf area, partitioning (13)C, sugar concentration, K content, and fruit and stem diameters of the plant. Compared with the control, K deficiency treatment severely decreased biomass of all organs. The treatment also depressed leaf photosynthesis and transport of (13)C assimilates, but the impact of stress on these activities became evident only after fruit and stem diameter expansions were down-regulated. These results suggested that K deficiency diminished sink activity in tomato plants prior to its effect on the source activity because of a direct effect on the water status of the former. The lack of demand in growth led to the accumulation of sugars in leaves and concomitant fall in photosynthetic activity. Since accumulation of K and sugars in the fruit was not affected, low K levels of the growing medium might not have affected the fruit quality. The micro-morphometric technique can be used as a reliable tool for monitoring K deficiency during fruiting of tomato. K deficiency directly hindered assimilate partitioning, and the symptoms were considered more detrimental compared with P deficiency.
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Affiliation(s)
- S Kanai
- Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-hiroshima, 739-8528, Japan
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Moghaieb REA, Tanaka N, Saneoka H, Murooka Y, Ono H, Morikawa H, Nakamura A, Nguyen NT, Suwa R, Fujita K. Characterization of salt tolerance in ectoine-transformed tobacco plants (Nicotiana tabaccum): photosynthesis, osmotic adjustment, and nitrogen partitioning. Plant Cell Environ 2006; 29:173-82. [PMID: 17080633 DOI: 10.1111/j.1365-3040.2005.01410.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes (ect. ABC) from Halomonas elongata were introduced to tobacco plants using an Agrobacterium-mediated gene delivery system. The genes for ectoine biosynthesis were integrated in a stable manner into the tobacco genome and the corresponding transcripts were expressed. The concentration of ectoine under salt-stress conditions was higher in the roots than in leaves. A close relationship was found between stomatal conductance and the amount of transported nitrogen, suggesting that water transport through the xylem in the stem and transpiration may be involved in nitrogen transport to leaves. The data indicate that the turgor values of the ectoine transgenic lines increased with increasing salt concentration. The data revealed two ways in which ectoine enhanced salinity tolerance of tobacco plants. First, ectoine improved the maintenance of root function so that water is taken up consistently and supplied to shoots under saline conditions. Second, ectoine enhanced the nitrogen supply to leaves by increasing transpiration and by protecting Rubisco proteins from deleterious effects of salt, thereby improving the rate of photosynthesis.
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Affiliation(s)
- R E A Moghaieb
- Department of Environmental Dynamics and Management, Graduate School of Biosphere Sciences, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan
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Banskota AH, Nguyen NT, Tezuka Y, Nobukawa T, Kadota S. Hypoglycemic effects of the wood of Taxus yunnanensis on streptozotocin-induced diabetic rats and its active components. Phytomedicine 2006; 13:109-14. [PMID: 16360940 DOI: 10.1016/j.phymed.2004.01.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2003] [Accepted: 01/22/2004] [Indexed: 05/05/2023]
Abstract
Hypoglycemic effects of the H(2)O and MeOH extracts of the wood of Taxus yunnanensis were examined in streptozotocin (STZ)-induced diabetic rats. The H(2)O extract significantly lowered the fasting blood glucose level by 33.7% at a 100mg/kg dose on intraperitoneal administration. From the active H(2)O extract of the wood, three lignans, i.e., isotaxiresinol (1), secoisolariciresinol (2) and taxiresinol (3), were isolated as major components. These lignans were further tested for their hypoglycemic effects on the same experimental model. At a dose of 100mg/kg (i.p.), isotaxiresinol (1) reduced the fasting blood glucose level of diabetic rats by 34.5%, while secoisolariciresinol (2) and taxiresinol (3) reduced by 33.4% and 20.9%, respectively. The blood glucose lowering effects of 1 and 2 were stronger than the mixture of tolbutamide (200mg/kg) and buformin (1mg/kg) used as a positive control, which lowered fasting blood glucose level by 24.0%.
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Affiliation(s)
- A H Banskota
- Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, 2630-Sugitani, Toyama 930-0194, Japan
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Nguyen NT, Gelfand D, Chang K, Varela JE, Nguyen TT, Hayashi M, Wilson SE, Luketich JD. Laparoscopic esophagectomy. MINERVA CHIR 2005; 60:327-38. [PMID: 16210983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Minimally invasive esophagectomy is emerging as an alternative option to open esophagectomy for benign and malignant esophageal diseases. This article provides a detailed review of the history of minimally invasive esophagectomy and an update on the currently accepted techniques for minimally invasive esophagectomy and its outcomes.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California at Irvine, Medical Center, Irvine, CA 92868, USA.
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27
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Nguyen NT, Morton JM, Wolfe BM, Schirmer B, Ali M, Traverso LW. The SAGES Bariatric Surgery Outcome Initiative. Surg Endosc 2005; 19:1429-38. [PMID: 16206007 DOI: 10.1007/s00464-005-0301-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Accepted: 06/06/2005] [Indexed: 12/11/2022]
Abstract
BACKGROUND The recent initiative for identifying centers of excellence in bariatric surgery calls for documentation of surgical outcomes. The SAGES Outcomes Initiative is a national database introduced in 1999 as a method for surgeons to accumulate and compare their data with summary national data. A bariatric-specific dataset was established later in 2001. The aim of this study was to compare the outcomes of bariatric surgery from the Society of American Gastrointestinal Endoscopic Surgeons' (SAGES) bariatric database with data derived from a national administrative database of academic centers. METHODS Between 2001 and 2004, 24 surgeons with 1,954 patients participated in the SAGES Bariatric Outcome Initiative, and 97 institutions with 42,847 patients participated in the University HealthSystem Consortium (UHC) database. Only 7 of the 24 surgeons participating in the SAGES Bariatric Outcome Initiative submitted more than 50 cases. The main outcome measures included demographics, comorbidities, type of bariatric procedure, operative time, length of hospital stay, short- and long-term complications, mortality, and weight loss. RESULTS Both datasets were comparable for gender. Roux-en-Y gastric bypass had been performed for 88% of the patients in the SAGES database and 96% of the patients in the UHC database. Associated comorbidities were similar between the two groups except for a higher rate of hyperlipidemia for the patients in the SAGES database. The SAGES database contains more bariatric-specific information such as body mass index, operative time, blood loss, bariatric-specific complications, long-term complications, and weight loss data than the UHC database. According to the available data, no statistically significant differences exist between the two datasets in terms of perioperative complications and mortality. CONCLUSIONS The SAGES Bariatric Outcome Initiative provides valuable bariatric-specific data not currently available in an administrative database that may be useful for benchmarking purposes. However, this database is currently underutilized.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Irvine Medical Center, Orange, CA 92868, USA.
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Abstract
The rising popularity of bariatric surgery over the past several years is attributable in part to the development of laparoscopic bariatric surgery. Morbidly obese patients have associated comorbid conditions that may predispose them to postoperative morbidity. The laparoscopic approach to bariatric surgery offers a minimally invasive option that reduces the physiologic stress and provides clinical benefits, as compared with the open approach. This review summarizes the impact of laparoscopic surgery on bariatric surgery, the various risk factors that could potentially predispose morbidly obese patients to postoperative morbidity, the fundamental differences between laparoscopic and open bariatric surgery, and the physiology of reduced tissue injury associated with laparoscopic bariatric surgery.
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Affiliation(s)
- D R Cottam
- Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Abstract
An investigation of the effect of resonator dimensions on nonlinear standing waves in shaped resonators is conducted. Simple forms of the shear viscosity term in the momentum equations are developed for an axisymmetric (2D) resonator and a low aspect ratio rectangular (3D) resonator. The cross sections of the resonators are exponentially expanded and the one-dimensional wave equations are solved by using the Galerkin's method. The quality factors, pressure waveforms, compression ratios, and resonance frequencies are calculated for different dimensionless cross sections and lengths of the resonators. The results show that, apart from the resonator length, the ratio of the cross-section dimension to the length of the resonator is an important parameter. If the ratio is greater than 0.04, the characteristics of the shaped resonator are not affected significantly. However, when the ratio is less than 0.01, the resonance becomes weak, the compression ratio drops substantially, and the frequency response changes as well.
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Affiliation(s)
- C Luo
- School of Mechanical and Production Engineering, Nanyang Technological University, Singapore 639798
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Nguyen NT, Gelfand D, Stevens CM, Chalifoux S, Chang K, Nguyen P, Luketich JD. Current status of minimally invasive esophagectomy. MINERVA CHIR 2004; 59:437-46. [PMID: 15494671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Minimally invasive esophagectomy is emerging as an option in the management of benign and malignant esophageal diseases. With minimally invasive esophagectomy, the conventional laparotomy is substituted with laparoscopy and the open thoracotomy with thoracoscopy. This article discusses the surgical techniques and outcomes for a variety of minimally invasive esophagectomy options.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Irvine Medical Center, Irvine, CA, USA.
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Nguyen NT, Anderson JT, Budd M, Fleming NW, Ho HS, Jahr J, Stevens CM, Wolfe BM. Effects of pneumoperitoneum on intraoperative pulmonary mechanics and gas exchange during laparoscopic gastric bypass. Surg Endosc 2004; 18:64-71. [PMID: 14625752 DOI: 10.1007/s00464-002-8786-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2002] [Accepted: 04/15/2003] [Indexed: 11/29/2022]
Abstract
BACKGROUND Hypercarbia and elevated intraabdominal pressure resulting from carbon dioxide (CO2) pneumoperitoneum can adversely affect respiratory mechanics. This study examined the changes in mechanical ventilation, CO2 homeostasis, and pulmonary gas exchange in morbidly obese patients undergoing a laparoscopic or open gastric bypass (GBP) procedure. METHODS In this study, 58 patients with a body mass index (BMI) of 40 to 60 kg/m2 were randomly allocated to laparoscopic ( n = 31) or open ( n = 27) GBP. Minute ventilation was adjusted to maintain a low normal arterial partial pressure of CO2 (PaCO2), low normal end-tidal partial pressure of CO2 (ETCO2), and low airway pressure. Respiratory compliance, ETCO2, peak inspiratory pressure (PIP), total exhaled CO2 per minute (VCO2), and pulse oximetry (SO2) were measured at 30-min intervals. The acid-base balance was determined by arterial blood gas analysis at 1-h intervals. The pulmonary gas exchange was evaluated by calculation of the alveolar dead space-to-tidal volume ratio (V(Dalv)/V(T)) and alveolar-arterial oxygen gradient (PAO2-PaO2). RESULTS The two groups were similar in age, gender, and BMI. As compared with open GBP, laparoscopic GBP resulted in higher ETCO2, PIP, and VCO2, and a lower respiratory compliance. Arterial blood gas analysis demonstrated higher PaCO2 and lower pH during laparoscopic GBP than during open GBP ( p < 0.05). The V(Dalv)/V(T) ratio and PAO2-PaO2 gradient did not change significantly during laparoscopic GBP. Intraoperative oxygen desaturation (SO2 < 90%) did not develop in any of the patients in either group. CONCLUSIONS Laparoscopic GBP alters intraoperative pulmonary mechanics and acid-base balance but does not significantly affect pulmonary oxygen exchange. Changes in pulmonary mechanics are well tolerated in morbidly obese patients when proper ventilator adjustments are maintained.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Irvine Medical Center, 101 The City Drive, Building 55, Room 106, Orange, CA 92868, USA.
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Nguyen NT, Saliminia A, Liu W, Chin SL, Vallée R. Optical breakdown versus filamentation in fused silica by use of femtosecond infrared laser pulses. Opt Lett 2003; 28:1591-1593. [PMID: 12956389 DOI: 10.1364/ol.28.001591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The competition between optical breakdown (OB) and laser-pulse filamentation (FL) in bulk fused silica is investigated by using a 1-kHz femtosecond infrared laser. We measure input powers corresponding to the threshold of OB and FL in terms of external focusing conditions. The results demonstrate that OB precedes FL for tight focusing, whereas for sufficiently long focal lengths FL takes places at a lower power than OB does.
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Affiliation(s)
- N T Nguyen
- Centre d'Optique, Photonique et Laser, Department of Physics, Université Laval, Québec, Canada, G1K 7P4
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Nguyen NT, Cronan M, Braley S, Rivers R, Wolfe BM. Duplex ultrasound assessment of femoral venous flow during laparoscopic and open gastric bypass. Surg Endosc 2003; 17:285-90. [PMID: 12364988 DOI: 10.1007/s00464-002-8812-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2002] [Accepted: 05/15/2002] [Indexed: 12/29/2022]
Abstract
BACKGROUND Pneumoperitoneum (PP) and the reverse Trendelenburg (RT) position have been shown to decrease femoral blood flow, resulting in venous stasis. However the effects of PP and RT on femoral venous flow have not been evaluated in morbidly obese patients undergoing laparoscopic gastric bypass (GBP). We analyzed the effects of PP and RT on peak systolic velocity and the cross-sectional area of the femoral vein during laparoscopic and open GBP. We further examined the efficacy of intermittent sequential compression devices in reversing the reduction of femoral peak systolic velocity. METHODS Thirty patients with a body mass index (BMI) of 40-60 were randomly allocated to under go either laparoscopic (n = 14) or open (n = 16) GBP. A duplex ultrasound examination of the femoral vein was performed at baseline, during PP and combined PP and RT in the laparoscopic group, and at baseline and during RT in the open group. The ultrasound exam was performed first without the use of sequential compression devices and then with the sequential compression devices inflated to 45 mmHg. RESULTS The two groups were similar in age, sex, BMI, and calf and thigh circumferences. During laparoscopic GBP, PP resulted in a 43% decrease in peak systolic velocity and a 52% increase in the cross-sectional area of the femoral vein; the combination of PP and RT decreased peak systolic velocity to 57% of baseline and increased the femoral cross-sectional area to 121% of baseline. During laparoscopic GBP, the use of sequential compression devices during PP and RT partially reversed the reduction of femoral peak systolic velocity, but femoral peak systolic velocity was still lower than baseline by 38%. During open GBP, RT resulted in a 38% reduction in peak systolic velocity and a 69% increase in the cross-sectional area of the femoral vein; the use of sequential compression devices during RT partially reversed these changes by increasing femoral peak systolic velocity by 26%; however, it was still lower than baseline by 22%. CONCLUSIONS Pneumoperitoneum and reverse Trendelenburg position during laparoscopic and open GBP are independent factors for the development of venous stasis. Combining the reverse Trendelenburg position with pneumoperitoneum during laparoscopic GBP further reduces femoral peak systolic velocity and hence increases venous stasis. The use of sequential compression devices was partially effective in reversing the reduction of femoral peak systolic velocity, but it did not return femoral peak systolic velocity to baseline levels.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California-Davis Medical Center, 2221 Stockton Blvd., 3rd Floor, Sacramento, CA 95817, USA.
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Nguyen NT, Furdui G, Fleming NW, Lee SJ, Goldman CD, Singh A, Wolfe BM. Effect of heated and humidified carbon dioxide gas on core temperature and postoperative pain: a randomized trial. Surg Endosc 2002; 16:1050-4. [PMID: 12165821 DOI: 10.1007/s00464-001-8237-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2001] [Accepted: 12/11/2001] [Indexed: 10/27/2022]
Abstract
BACKGROUND Intraoperative hypothermia is a common event during laparoscopic operations. An external warming blanket has been shown to be effective in preventing hypothermia. It has now been proposed that using heated and humidified insufflation gas can prevent hypothermia and decrease postoperative pain. Therefore, we examined the extent of intraoperative hypothermia in patients undergoing laparoscopic Nissen fundoplication using an upper body warming blanket. We also attempted to determine whether using heated and humidified insufflation gas in addition to an external warming blanket would help to maintain intraoperative core temperature or decrease postoperative pain. METHODS Twenty patients were randomized to receive either standard carbon dioxide (CO2) gas (control, n = 10) or heated and humidified gas (heated and humidified, n = 10). After the induction of anesthesia, an external warming blanket was placed on all patients in both groups. Intraoperative core temperature and intraabdominal temperature were measured at 15-min intervals. Postoperative pain intensity was assessed using a visual analogue pain scale, and the amount of analgesic consumption was recorded. Volume of gas delivered, number of lens-fogging episodes, intraoperative urine output, and hemodynamic data were also recorded. RESULTS There was no significant difference between the two groups in age, length of operation, or volume of CO2 gas delivered. Compared with baseline value, mean core temperature increased by 0.4 degrees C in the heated and humidified group and by 0.3 degrees C in the control group at 1.5 h after surgical incision. Intraabdominal temperature increased by 0.2 degrees C in the heated and humidified group but decreased by 0.5 degrees C in the control group at 1.5 h after abdominal insufflation. There was no significant difference between the two groups in visual analog pain scale (5.4 +/- 1.6 control vs 4.5 +/- 2.8 heated and humidified), morphine consumed (27 +/- 26 mg control vs 32 +/- 19 mg heated and humidified), urine output, lens-fogging episodes, or hemodynamic parameters. CONCLUSION Heated and humidified gas, when used in addition to an external warming blanket, minimized the reduction of intraabdominal temperature but did not alter core temperature or reduce postoperative pain.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California-Davis, Medical Center, 2221 Stockton Blvd., Sacramento, CA 95817-1418, USA.
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Nguyen NT, Wolfe BM. Current status of laparoscopic gastric bypass. MINERVA CHIR 2002; 57:249-56. [PMID: 12029218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Laparoscopic gastric bypass is emerging as a commonly performed procedure for the treatment of morbid obesity. This article discusses the indications for surgery, patient selection, surgical technique, management of complications, and outcomes of laparoscopic gastric bypass.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Davis, Medical Center, Sacramento, CA, USA.
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Nguyen NT, Ho HS, Fleming NW, Moore P, Lee SJ, Goldman CD, Cole CJ, Wolfe BM. Cardiac function during laparoscopic vs open gastric bypass. Surg Endosc 2002; 16:78-83. [PMID: 11961610 DOI: 10.1007/s00464-001-8159-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2001] [Accepted: 06/26/2001] [Indexed: 10/28/2022]
Abstract
BACKGROUND Hypercarbia and increased intraabdominal pressure during prolonged pneumoperitoneum can adversely affect cardiac function. This study compared the intraoperative hemodynamics of morbidly obese patients during laparoscopic and open gastric bypass (GBP). METHODS Fifty-one patients with a body mass index (BMI) of 40-60 kg/m2 were randomly allocated to undergo laparoscopic (n = 25) or open (n = 26) GBP. Cardiac output (CO), mean pulmonary artery pressure (MPAP), pulmonary artery wedge pressure (PAWP), central venous pressure (CVP), heart rate (HR), and mean arterial pressure (MAP) were recorded at baseline, intraoperatively at 30-min intervals, and in the recovery room. Systemic vascular resistance (SVR) and stroke volume (SV) were also calculated. RESULTS The two groups were similar in terms of age, weight, and BMI. Operative time was longer in the laparoscopic than in the open group (p < 0.05). The HR and MAP increased significantly from baseline intraoperatively, but there was no significant difference between the two groups. In the laparoscopic group, CO was unchanged after insufflation, but it increased by 5.3% at 2.5 h compared to baseline and by 43% compared to baseline in the recovery room. In contrast, during open GBP, CO increased significantly by 25% after surgical incision and remained elevated throughout the operation. CO was higher during open GBP than during laparoscopic GBP at 0.5 h and at 1 h after surgical incision (p < 0.05). During laparoscopic GBP, CVP, MPAP, and SVR increased transiently and PAWP remained unchanged. During open GBP, CVP, MPAP, and PAWP decreased transiently and SVR remained unchanged. There was no significant difference in the amount of intraoperative fluid administered during laparoscopic (5.5 +/- 1.6 L) and open (5.6 +/- 1.7 L) GBP. CONCLUSION Prolonged pneumoperitoneum during laparoscopic gastric bypass does not impair cardiac function and is well tolerated by morbidly obese patients.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California-Davis Medical Center, 2221 Stockton Blvd., 3rd Floor, Sacramento, CA 95817, USA.
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Jamil NE, Nguyen NT, Falk C, Frederiksen T, Deleuran BW. [Heavy white coats are not the cause of physicians' headaches and shoulder pain]. Ugeskr Laeger 2001; 163:7271-2. [PMID: 11797560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The weight of doctors' white coats was examined and correlated to the degree of headache and muscle pain in the shoulders. The coat weight of doctors was 1.5 kg (1.1 kg-1.9 kg) (median with 25%-75% in parenthesis). The highest weight was found in the coats of young physicians 2.0 kg (1.7 kg-2.2 kg), which was higher than those of young surgeons. No correlation was seen in the degree of headache and muscle pain in the shoulders. With the long walking distances in hospitals, it would seem that internal medicine is not only an intellectually, but also a physically, demanding job.
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Affiliation(s)
- N E Jamil
- Odense Universitetshospital, medicinsk afdeling C
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Abstract
Minimally invasive oesophagectomy is a relatively new procedure that is performed by means of thoracoscopy and laparoscopy. One stage of the procedure involves creation of a peritoneo-pleural communication in the presence of a pneumoperitoneum. In the case presented, severe hypotension occurred at this point. We believe this was caused by the escape of carbon dioxide from the peritoneal cavity into the right hemithorax, resulting in tension pneumothorax and cardiac tamponade. We believe this to be a predictable complication of this procedure but one that if expected, recognised and correctly managed, should not result in adverse outcomes.
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Affiliation(s)
- P P McConkey
- Department of Anesthesiology, University of California, Davis, Medical Center, Sacramento, USA
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Nguyen NT, Roberts PF, Follette DM, Lau D, Lee J, Urayama S, Wolfe BM, Goodnight JE. Evaluation of minimally invasive surgical staging for esophageal cancer. Am J Surg 2001; 182:702-6. [PMID: 11839342 DOI: 10.1016/s0002-9610(01)00804-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Conventional imaging studies (computed tomography and endoscopic esophageal ultrasonography) used for preoperative evaluation of patients with esophageal cancer can be inaccurate for detection of small metastatic deposits. We evaluated the efficacy of minimally invasive surgical (MIS) staging as an additional modality for evaluation of patients with esophageal cancer. METHODS Between December 1998 and February 2001, 33 patients with esophageal cancer were evaluated for surgical resection. Conventional imaging studies demonstrated operable disease in 31 patients and equivocal findings in 2 patients. All patients then underwent MIS staging (laparoscopy, bronchoscopy, and ultrasonography of the liver). We compared the results from surgical resection and MIS staging with those from conventional imaging. RESULTS MIS staging altered the treatment plan in 12 (36%) of 33 patients; MIS staging upstaged 10 patients with operable disease and downstaged 2 patients with equivocal findings. MIS staging accurately determined resectability in 97% of patients compared with 61% of patients staged by conventional imaging. The specificity and negative predictive value for detection of unsuspected metastatic disease in MIS staging were 100% and 96%, respectively, compared with 91% and 65%, respectively, for conventional imaging studies. CONCLUSION In addition to conventional imaging studies, MIS staging should be included routinely in the preoperative work-up of patients with esophageal cancer.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Davis, Medical Center, 2221 Stockton Blvd., 3rd Flr., Sacramento, CA 95817-2214, USA.
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Nguyen NT, Ho HS, Smith WD, Philipps C, Lewis C, De Vera RM, Berguer R. An ergonomic evaluation of surgeons' axial skeletal and upper extremity movements during laparoscopic and open surgery. Am J Surg 2001; 182:720-4. [PMID: 11839346 DOI: 10.1016/s0002-9610(01)00801-7] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Many surgeons have complained of fatigue and musculoskeletal pain after laparoscopic surgery. We evaluated differences in surgeons' axial skeletal and upper extremity movements during laparoscopic and open operations. METHODS Five surgeons were videotaped performing 16 operations (8 laparoscopic and 8 open) to record their neck, trunk, shoulder, elbow, and wrist movements during the first hour of surgery. We also compared postprocedural complaints of pain, stiffness, or numbness between the two groups. RESULTS Compared with surgeons performing open surgery, surgeons performing laparoscopic surgery exhibited less lateral neck flexion; less trunk flexion; more internal rotation of the shoulders; more elbow flexion; more wrist supination and wrist ulnar and radial deviation. There was a trend of more shoulder stiffness after laparoscopic operations than after open operations. CONCLUSIONS Laparoscopic surgery involves a more static posture of the neck and trunk, but more frequent awkward movements of the upper extremities than open surgery. Ergonomic changes in the operating room environment and instrument design could ease the physical stress imposed on surgeons during laparoscopic operations.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of Califorinia, Davis, Medical Center, 2221 Stockton Blvd., 3rd Flr., Sacramento, CA 95817-2214, USA.
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Nguyen NT, Maurus R, Stokell DJ, Ayed A, Duckworth HW, Brayer GD. Comparative analysis of folding and substrate binding sites between regulated hexameric type II citrate synthases and unregulated dimeric type I enzymes. Biochemistry 2001; 40:13177-87. [PMID: 11683626 DOI: 10.1021/bi010408o] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe the first structure determination of a type II citrate synthase, an enzyme uniquely found in Gram-negative bacteria. Such enzymes are hexameric and are strongly and specifically inhibited by NADH through an allosteric mechanism. This is in contrast to the widespread dimeric type I citrate synthases found in other organisms, which do not show allosteric properties. Our structure of the hexameric type II citrate synthase from Escherichia coli is composed of three identical dimer units arranged about a central 3-fold axis. The interactions that lead to hexamer formation are concentrated in a relatively small region composed of helix F, FG and IJ helical turns, and a seven-residue loop between helices J and K. This latter loop is present only in type II citrate synthase sequences. Running through the middle of the hexamer complex, and along the 3-fold axis relating dimer units, is a remarkable pore lined with 18 cationic residues and an associated hydrogen-bonded network. Also unexpected was the observation of a novel N-terminal domain, formed by the collective interactions of the first 52 residues from the two subunits of each dimer. The domain formed is rich in beta-sheet structure and has no counterpart in previous structural studies of type I citrate synthases. This domain is located well away from the dimer-dimer contacts that form the hexamer, and it is not involved in hexamer formation. Another surprising observation from the structure of type II E. coli citrate synthase is the unusual polypeptide chain folding found at the putative acetylcoenzyme A binding site. Key parts of this region, including His264 and a portion of polypeptide chain known from type I structures to form an adenine binding loop (residues 299-303), are shifted by as much as 10 A from where they must be for substrate binding and catalysis to occur. Furthermore, the adjacent polypeptide chain composed of residues 267-297 is extremely mobile in our structure. Thus, acetylcoenzyme A binding to type II E. coli citrate synthase would require substantial structural shifts and a concerted refolding of the polypeptide chain to form an appropriate binding subsite. We propose that this essential rearrangement of the acetylcoenzyme A binding part of the active site is also a major feature of allostery in type II citrate synthases. Overall, this study suggests that the evolutionary development of hexameric association, the elaboration of a novel N-terminal domain, introduction of a NADH binding site, and the need to refold a key substrate binding site are all elements that have been developed to allow for the allosteric control of catalysis in the type II citrate synthases.
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Affiliation(s)
- N T Nguyen
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver V6T 1Z3, Canada
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Pastor SA, Singh K, Lee DA, Juzych MS, Lin SC, Netland PA, Nguyen NT. Cyclophotocoagulation: a report by the American Academy of Ophthalmology. Ophthalmology 2001; 108:2130-8. [PMID: 11713091 DOI: 10.1016/s0161-6420(01)00889-2] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE This document describes cyclophotocoagulation procedures for glaucoma and examines the evidence to answer key questions about patient selection, and efficacy of transscleral and endoscopic techniques. METHODS A literature search conducted for the years 1968 to 2000 retrieved 130 citations. The author reviewed 34 of these articles and selected 19 for the panel methodologist to review and rate according to the strength of evidence. A Level I rating is assigned to properly conducted, well-designed, randomized clinical trials; a Level II rating is assigned to well-designed cohort and case-control studies; and a Level III rating is assigned to case series and poorly designed prospective and retrospective studies, including case-control studies. RESULTS The predominant problem with all studies on cyclophotocoagulation is the lack of a uniform definition of success, which makes comparisons difficult. One randomized controlled trial (Level I evidence) compared the efficacy of transscleral cyclophotocoagulation with noncontact Nd:YAG and semiconductor diode laser. It found no significant difference between the two, although a significant problem was the variability allowed with laser parameters. Most of the literature consists of noncomparative case series that provide evidence that is limited and often not convincing. CONCLUSION Cyclophotocoagulation is indicated for patients with refractory glaucoma who have failed trabeculectomy or tube shunt procedures, patients with minimal useful vision and elevated intraocular pressure, and patients who have no visual potential and need pain relief (based on Level III evidence). It may be useful for patients whose general medical condition precludes invasive surgery or who refuse more aggressive surgery (i.e., filter or tube). It is also useful in emergent situations, such as the acute onset of neovascular glaucoma. There is insufficient evidence to definitively compare the relative efficacy of the cyclophotocoagulation procedures for glaucoma. It is the panel's opinion, however, that semiconductor diode systems appear to possess the best combination of effectiveness (based on Level III evidence), portability, expense, and ease of use at this time.
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Abstract
BACKGROUND Intraoperative hypothermia is a common event during open and laparoscopic abdominal surgery. The aim of this study was to compare changes in core temperature between laparoscopic and open gastric bypass (GBP). METHODS 101 patients with a body mass index (BMI) of 40-60 kg/m2 were randomly assigned to open (n = 50) or laparoscopic (n = 51) GBP. Anesthetic technique was similar for both groups. An external warming blanket and passive airway humidification were used intraoperatively. Core temperature was recorded at preanesthesia, at baseline (after induction) and at 30-min intervals; intra-abdominal temperature was additionally measured at 30-min intervals in a subset of 30 laparoscopic GBP patients. The number of patients who developed intraoperative and postoperative hypothermia (< 36 degrees C) was recorded. Length of operation for both groups and the amount of CO2 gas delivered during laparoscopic operations were also recorded. RESULTS There was no significant difference between groups with respect to age, gender, mean BMI, and amount of intravenous fluid administered. After induction of anesthesia, core temperature significantly decreased in both groups; 36% of patients in the open group and 37% of patients in the laparoscopic group developed hypothermia. This percentage increased to 46% in the open group and 41% in the laparoscopic group during the operation, and then decreased to 6% in the open group and 8% in the laparoscopic group in the recovery-room. Core temperature increased during the operative procedure to reach 36.5 +/- 0.6 degrees C in the open group and 36.3 +/- 0.5 degrees C in the laparoscopic group at 2.5 hours after surgical incision. Intra-abdominal temperature during laparoscopic GBP was significantly lower than core temperature at all measurement points (p < 0.05). Operative time was longer in the laparoscopic group than in the open group (232 +/- 43 vs 201 +/- 38 min, p < 0.01). Mean volume of gas delivered during laparoscopic GBP was 650 +/- 220 liters. CONCLUSION Perioperative hypothermia was a common event during both laparoscopic and open GBP. Despite a longer operative time, laparoscopic GBP did not increase the rate of intraoperative hypothermia when efforts were made to minimize intraoperative heat loss.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Davis, Medical Center, 2221 Stockton Blvd, 3rd Floor, Sacramento, CA 05617-1418, USA.
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Nguyen NT, Goldman C, Rosenquist CJ, Arango A, Cole CJ, Lee SJ, Wolfe BM. Laparoscopic versus open gastric bypass: a randomized study of outcomes, quality of life, and costs. Ann Surg 2001; 234:279-89; discussion 289-91. [PMID: 11524581 PMCID: PMC1422019 DOI: 10.1097/00000658-200109000-00002] [Citation(s) in RCA: 763] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To compare outcomes, quality of life (QOL), and costs of laparoscopic and open gastric bypass (GBP). SUMMARY BACKGROUND DATA Laparoscopic GBP has been reported to be a safe and effective approach for the treatment of morbid obesity. The authors performed a prospective randomized trial to compare outcomes, QOL, and costs of laparoscopic GBP with those of open GBP. METHODS From May 1999 to March 2001, 155 patients with a body mass index (BMI) of 40 to 60 kg/m2 were randomly assigned to undergo laparoscopic (n = 79) or open (n = 76) GBP. The two groups were similar in age, sex ratio, mean BMI, and comorbidities. Main outcome measures included operative time, estimated blood loss, length of hospital stay, operative complications, percentage of excess body weight loss, and time to return to activities of daily living and work. Changes in QOL were assessed using the SF-36 Health Survey and the bariatric analysis of reporting outcome system (BAROS). Operative and hospital costs of the two operations were also compared. RESULTS There were no deaths in either group. Mean operative time was longer for laparoscopic GBP than for open GBP, but operative blood loss was less. Two (2.5%) of the 79 patients in the laparoscopic group required conversion to laparotomy. Median length of hospital stay was shorter for laparoscopic GBP patients (3 vs 4 days). The rate of postoperative anastomotic leak was similar between groups. Wound-related complications such as infection (10.5 vs 1.3%) and incisional hernia (7.9 vs 0%) were more common after open GBP; late anastomotic stricture was less frequent after open GBP (2.6 vs 11.4%). Time to return to activities of daily living and work were shorter after laparoscopic GBP than after open GBP. Weight loss at 1 year was similar between groups. Preoperative SF-36 scores were similar between groups; however, at 1 month after surgery, laparoscopic patients had better physical conditioning, social functioning, general health, and less body pain than open GBP patients. At 6 months, the BAROS outcome was classified as good or better in 97% of laparoscopic GBP patients compared with 82% of open GBP patients. Operative costs were higher for laparoscopic GBP patients, but hospital costs were lower. CONCLUSIONS Laparoscopic GBP is a safe and cost-effective alternative to open GBP. Despite a longer operative time, patients undergoing laparoscopic GBP benefited from less blood loss, a shorter hospital stay, and faster convalescence. Laparoscopic GBP patients had comparable weight loss at 1 year but a more rapid improvement in QOL than open GBP patients. The higher initial operative costs for laparoscopic GBP were adequately offset by the lower hospital costs.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Davis, Medical Center, Sacramento, California 95817-1814, USA.
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Abstract
BACKGROUND Increased intra-abdominal pressure (IAP) postoperatively can adversely affect cardiovascular, pulmonary, and renal function. In this prospective, randomized trial, we compared the IAP in morbidly obese patients after laparoscopic and open gastric bypass (GBP) surgery. METHODS 64 patients with a body mass index of 40 to 60 kg/m2 were randomized to undergo laparoscopic or open GBP. IAPs were obtained at baseline (after induction of anesthesia), immediately after the operation, and on post-operative day (POD) 1, 2, and 3. Intraoperative and postoperative fluid requirements, urine output, and creatinine clearance were recorded. RESULTS Demographics of the two groups were similar. IAP increased from baseline immediately after laparoscopic and open GBP (p < 0.05). IAP returned to baseline by POD 2 after laparoscopic GBP but remained elevated through POD 3 after open GBP. In fact, IAP was lower after laparoscopic GBP than after open GBP on POD 1, 2 and 3 (p < 0.05). The amount of intraoperative IV fluid was similar between groups, but laparoscopic GBP required less IV fluid and facilitated higher urine output postoperatively than open GBP. There was no significant difference in creatinine clearance between groups. CONCLUSIONS Laparoscopic GBP resulted in significantly lower IAP, less postoperative fluid required, and greater postoperative urine output than open GBP.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Davis, Medical Center, Sacramento 95817-1418, USA.
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Abstract
Ivor Lewis esophagectomy consists of a laparotomy and right thoracotomy for resection of the intrathoracic esophagus. Recent advances in minimally invasive surgical technology have allowed surgeons to apply laparoscopy and thoracoscopy to perform esophagectomy. However, there have been few reports that describe a totally minimally invasive Ivor Lewis esophagectomy. We present a case of combined laparoscopic and thoracoscopic resection of the distal third esophagus with an intrathoracic esophagogastric reconstruction for esophageal carcinoma.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Davis, Medical Center, Sacramento 95817-1418, USA.
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Nguyen NT, Owings JT, Gosselin R, Pevec WC, Lee SJ, Goldman C, Wolfe BM. Systemic coagulation and fibrinolysis after laparoscopic and open gastric bypass. Arch Surg 2001; 136:909-16. [PMID: 11485526 DOI: 10.1001/archsurg.136.8.909] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
HYPOTHESIS Laparoscopic gastric bypass (GBP) induces a postoperative hypercoagulable state that is similar or reduced compared with open GBP. SETTING University hospital. PATIENTS Between May 1999 and June 2000, 70 patients were randomly assigned to laparoscopic (n = 36) or open (n = 34) GBP. Deep venous thrombosis (DVT) prophylaxis consisted of antiembolism stockings and sequential pneumatic compression devices. MAIN OUTCOME MEASURES Plasminogen, thrombin-antithrombin complex (TAT), prothrombin fragment 1.2 (F1.2), fibrinogen, D-dimer, antithrombin III (AT), and protein C levels were measured at baseline and at 1, 24, 48, and 72 hours postoperatively. A venous duplex examination of both lower extremities was performed preoperatively and between the third and fifth day postoperatively. RESULTS The 2 groups were similar in age, weight, and body mass index. Plasminogen levels decreased, and TAT, F1.2, and fibrinogen levels increased after laparoscopic and open GBP. There was no significant difference in these levels between groups. D-dimer levels increased in both groups, but the levels were significantly higher after open GBP than after laparoscopic GBP (P<.01). Antithrombin III and protein C levels decreased in both groups. The reduction of AT (at 1 hour) and protein C (at 72 hours) was significantly less after laparoscopic GBP than after open GBP (P<.05). Postoperative venous duplex examination revealed DVT in 1 (2.9%) of 34 patients after open GBP but in none of 36 patients after laparoscopic GBP. One patient developed pulmonary embolism after open GBP. CONCLUSIONS Laparoscopic GBP induces a hypercoagulable state similar to that of open GBP. Our findings suggest that DVT prophylaxis should be used during laparoscopic GBP as in open GBP.
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Affiliation(s)
- N T Nguyen
- Department of Surgery, University of California, Davis, Medical Center, 2221 Stockton Blvd, 3rd Floor, Sacramento, CA 95817-1418, USA.
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Goetsch L, Plotnicky-Gilquin H, Aubry JP, De-Lys P, Haeuw JF, Bonnefoy JY, Nguyen NT, Corvaïa N, Velin D. BBG2Na an RSV subunit vaccine candidate intramuscularly injected to human confers protection against viral challenge after nasal immunization in mice. Vaccine 2001; 19:4036-42. [PMID: 11427280 DOI: 10.1016/s0264-410x(01)00105-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Respiratory syncytial virus (RSV) is a major respiratory pathogen responsible for severe pulmonary disease. We have developed a parenterally administered vaccine, BBG2Na, which is currently in a phase III clinical trial. BBG2Na comprises residues 130--230 of RSV-A G protein (G2Na) fused to the BB carrier protein. In this study, we show that BBG2Na can be delivered by the nasal route and generates both mucosal and systemic antibody responses when co-administered with cholera toxin B or a newly described delivery system, zwittergent 3--14. We found that nasal BBG2Na administration protects against RSV challenge and does not induce lung immunopathology upon subsequent RSV challenge.
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Affiliation(s)
- L Goetsch
- Centre d'Immunologie Pierre Fabre, 5 avenue Napoléon III, B.P. 497, F-74164 St Julien en Genevois, France
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Christie NA, Buenaventura PO, Fernando HC, Nguyen NT, Weigel TL, Ferson PF, Luketich JD. Results of expandable metal stents for malignant esophageal obstruction in 100 patients: short-term and long-term follow-up. Ann Thorac Surg 2001; 71:1797-801; discussion 1801-2. [PMID: 11426750 DOI: 10.1016/s0003-4975(01)02619-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Expandable metal stents palliate malignant dysphagia in most cases, but early complications and outcomes in long-term survivors have not been well described. This report summarizes our experience with expandable metal stents for malignant dysphagia. METHODS Over a 48-month period, 127 stents were placed in 100 patients with dysphagia from esophageal cancer (93%) or lung cancer. Most had undergone prior treatment. Dysphagia scores, duration of palliation, complications, and reintervention were evaluated. RESULTS Immediate improvement in dysphagia was observed in 85% of patients with no procedure-related deaths. Dysphagia score decreased from 3.3 before stent to 2.3 (p < 0.005). Average interval to reintervention was 80 days. In 40 patients surviving more than 120 days, 31 (78%) required reintervention. Major complications occurred in 3 patients receiving poststent chemoradiation (tracheoesophageal fistula, T1 vertebral body abscess, mediastinal abscess). Other complications included unsatisfactory deployment requiring immediate removal (3 patients), migration (11 patients), pain requiring removal (2 patients), food impaction (10 patients), and tumor ingrowth (37 patients). CONCLUSIONS Expandable metal stents offer excellent short-term palliation of malignant dysphagia. In long-term survivors, recurrent dysphagia requiring reintervention is common. In a small subset of patients receiving chemoradiation after stent placement, major complications were observed.
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Affiliation(s)
- N A Christie
- Section of Thoracic Surgery, University of Pittsburgh, Pennsylvania, USA
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Matsunari I, Haas F, Nguyen NT, Reidel G, Wolf I, Senekowitsch-Schmidtke R, Stöcklin G, Schwaiger M. Comparison of sestamibi, tetrofosmin, and Q12 retention in porcine myocardium. J Nucl Med 2001; 42:818-23. [PMID: 11337582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
UNLABELLED Although there are several 99mTc perfusion tracers introduced for clinical use, there are no data available directly comparing these tracers with microsphere-determined flow. The aim of this study was to compare the myocardial retention of sestamibi, tetrofosmin, and Q12 in a porcine model. METHODS We used a pig model with (n = 6) or without (n = 3) coronary occlusion. Each pig received a simultaneous injection of sestamibi and either tetrofosmin (group 1, n = 5) or Q12 (group 2, n = 4) labeled with either 99mTc or 95mTc (physical half-life, 61 d; photon energy, 204 keV) during pharmacologic vasodilation. Absolute myocardial retention of each tracer was calculated from the myocardial tracer activity and arterial input function. RESULTS The plot of all three tracers versus flow achieved a plateau at a higher flow range. However, sestamibi showed a higher mean retention than either tetrofosmin (group 1, 0.27 +/- 0.11 vs. 0.16 +/- 0.06 mL/g/min, respectively; P < 0.01) or Q12 (group 2, 0.32 +/- 0.13 vs. 0.09 +/- 0.03 mL/g/min, respectively; P < 0.01). Furthermore, when a linear regression analysis was performed to assess the relationship between retention and microsphere-determined flow, sestamibi showed a greater increment in retention than did tetrofosmin or Q12. CONCLUSION Although all of the tracers showed a nonlinear increase in retention as flow increased, sestamibi may display more favorable characteristics as a flow tracer in the porcine heart.
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Affiliation(s)
- I Matsunari
- Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Germany
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