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Sun H, Wu Y, Sung L, Lin X, Tsai F, Lin Y, Tam K, Wang F, Chang S. Use of consecutive transcutaneous oxygen measurement when assessing the need for revascularization and association with the outcomes of ischemic diabetic ulcers. Int Wound J 2024; 21:e14635. [PMID: 38272805 PMCID: PMC10789651 DOI: 10.1111/iwj.14635] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/17/2023] [Accepted: 12/17/2023] [Indexed: 01/27/2024] Open
Abstract
This study compared the ankle-brachial index (ABI) with transcutaneous oxygen pressure (TcPO2 ) in assessing peripheral vascular disease (PVD) prevalence in 100 diabetic foot ulcer (DFU) patients. Patients were categorized into vascular or nonvascular reconstruction groups and underwent both ABI and TcPO2 measurements four times over 6 months. Predictive validity for PVD diagnosis was analysed using the area under the receiver-operating characteristic curve (AUC). The study found TcPO2 to be a superior predictor of PVD than ABI. Among the DFU patients, 51 with abnormal TcPO2 values underwent vascular reconstruction. Only TcPO2 values showed significant pretreatment differences between the groups and increased post-reconstruction. These values declined over a 6-month follow-up, whereas ABI values rose. For those with end-stage renal disease (ESRD), TcPO2 values saw a sharp decrease within 3 months. Pre-reconstruction TcPO2 was notably lower in amputation patients versus limb salvage surgery patients. In conclusion, TcPO2 is more effective than ABI for evaluating ischemic limb perfusion and revascularization necessity. It should be prioritized as the primary follow-up tool, especially for ESRD patients.
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Affiliation(s)
- Hao‐Yi Sun
- School of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
| | - Yi‐Chun Wu
- Division of Plastic Surgery, Integrated Burn & Wound Care Center, Department of SurgeryShuang‐Ho HospitalNew Taipei CityTaiwan
- Department of Biomedical EngineeringNational Yang Ming Chiao Tung UniversityTaipeiTaiwan
| | - Li‐Chin Sung
- Division of Cardiology, Department of Internal Medicine, School of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
- Division of Cardiology, Department of Internal Medicine, Shuang‐Ho HospitalTaipei Medical UniversityNew Taipei CityTaiwan
- Taipei Heart InstituteTaipei Medical UniversityTaipeiTaiwan
- TMU Research Center of Urology and Kidney (TMU‐RCUK)Taipei Medical UniversityTaipeiTaiwan
| | - Xin‐Yi Lin
- Division of Plastic Surgery, Integrated Burn & Wound Care Center, Department of SurgeryShuang‐Ho HospitalNew Taipei CityTaiwan
| | - Feng‐Chou Tsai
- Division of Plastic Surgery, Integrated Burn & Wound Care Center, Department of SurgeryShuang‐Ho HospitalNew Taipei CityTaiwan
- Department of Surgery, School of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
| | - Yen‐Kuang Lin
- Graduate Institute of Athletics and Coaching ScienceNational Taiwan Sport UniversityTaoyuanTaiwan
| | - Ka‐Wai Tam
- Division of General Surgery, Department of Surgery, Shuang‐Ho HospitalTaipei Medical UniversityNew Taipei CityTaiwan
- Division of General Surgery, Department of Surgery, School of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
- Cochrane TaiwanTaipei Medical UniversityTaipeiTaiwan
| | - Fu‐Yu Wang
- Cabrini HospitalMelbourneVictoriaAustralia
| | - Shun‐Cheng Chang
- Division of Plastic Surgery, Integrated Burn & Wound Care Center, Department of SurgeryShuang‐Ho HospitalNew Taipei CityTaiwan
- Department of Surgery, School of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
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Chiang A, Tam K, Au-Yeung R. COMBINED BORTEZOMIB AND VENETOCLAX TARGETS THE PRO-SURVIVAL FUNCTIONS OF LATENT VIRAL PROTEINS IN EPSTEIN-BARR VIRUS-DRIVEN LYMPHOPROLIFERATIVE DISEASES. Leuk Res 2022. [DOI: 10.1016/s0145-2126(22)00228-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Boguslawski KM, McKeown AN, Day CJ, Lacey KA, Tam K, Vozhilla N, Kim SY, Jennings MP, Koralov SB, Elde NC, Torres VJ. Exploiting species specificity to understand the tropism of a human-specific toxin. Sci Adv 2020; 6:eaax7515. [PMID: 32195339 PMCID: PMC7065885 DOI: 10.1126/sciadv.aax7515] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 12/17/2019] [Indexed: 06/10/2023]
Abstract
Many pathogens produce virulence factors that are specific toward their natural host. Clinically relevant methicillin-resistant Staphylococcus aureus (MRSA) isolates are highly adapted to humans and produce an array of human-specific virulence factors. One such factor is LukAB, a recently identified pore-forming toxin that targets human phagocytes by binding to the integrin component CD11b. LukAB exhibits strong tropism toward human, but not murine, CD11b. Here, phylogenetics and biochemical studies lead to the identification of an 11-residue domain required for the specificity of LukAB toward human CD11b, which is sufficient to render murine CD11b compatible with toxin binding. CRISPR-mediated gene editing was used to replace this domain, resulting in a "humanized" mouse. In vivo studies revealed that the humanized mice exhibit enhanced susceptibility to MRSA bloodstream infection, a phenotype mediated by LukAB. Thus, these studies establish LukAB as an important toxin for MRSA bacteremia and describe a new mouse model to study MRSA pathobiology.
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Affiliation(s)
- K. M. Boguslawski
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - A. N. McKeown
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - C. J. Day
- Institute for Glycomics, Griffith University, Gold Coast, QLD 4222, Australia
| | - K. A. Lacey
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - K. Tam
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - N. Vozhilla
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - S. Y. Kim
- Office of Collaborative Sciences, New York University School of Medicine, New York, NY 10016, USA
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - M. P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, QLD 4222, Australia
| | - S. B. Koralov
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - N. C. Elde
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - V. J. Torres
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
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Harbtn DN, Amleh A, Bernes A, Bodzian F, Boyer K, Conaway J, Dias H, Dommarco R, Duverney-Pret P, Earnest S, Ely D, Fornarelli L, Förster R, Gentry G, Görlitz G, Gomez F, Guess P, Hähnchen K, Hamilton D, Halley M, Hathaway M, Hickes H, Isono K, Kulinna H, Lucas P, Manger P, Manso L, Moffett S, Müller T, Orii T, Paul R, Reubke K, Rivera L, Rubbiani M, Schetter J, Schulz D, Shaocong L, Smead F, Tam K, Tengler H, Torma L, del Valle M, Verweij A, Walls G, Weiping G. Quantitation of Tebuconazole in Liquid and Solid Formulations by Capillary GC: Collaborative Study. J AOAC Int 2020. [DOI: 10.1093/jaoac/80.4.703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
A capillary gas chromatographic method has been developed for quantitation of tebuconazole (Folicur, Elite, Raxil, Lynx) in liquid and solid formulations. Tebuconazole is a broad-spectrum, systemic foliar fungicide used to control diseases of wheat, barley, peanut, and grasses grown for seed. Samples are dissolved in acetone and analyzed by capillary gas chromatography (GC) with dicyclohexyl phthalate as internal standard. Twenty-two laboratories from 11 countries participated in a collaborative study of the method. Each collaborator was provided reference standard, internal standard, and blind duplicate samples from 6 formulations: aqueous flowable (F), aqueous emulsifiable concentrate (EW), emulsifiable concentrate for seed treatment (ES), flowable for seed treatment (FS), wettable powder (WP), and dry flowable (DF). Collaborators were instructed to use peak area measurements for quantitation. The seed treatment flowable formulation required confirmation of accurate integration values by the collaborator. Relative standard deviation values for reproducibility (RSDR) for analysis of the formulations were as follows: 3.6 lb/gal F, 1.22; 250 g/L EW, 1.13; 15 g/L ES, 2.40; 25 g/L FS, 2.65; 25% WP, 0.96; 25% DF, 0.72; 45% DF, 0.72. The capillary GC method for quantitation of tebuconazole in fungicide formulations has been adopted first action by AOAC INTERNATIONAL.
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Affiliation(s)
- Donald N Harbtn
- Bayer Corporation, Agriculture Division, PO Box 4913, 8400 Hawthorne Rd, Kansas City, MO 64120-0013
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Abstract
BACKGROUND Maintaining long-term vascular access patency is necessary for high quality haemodialysis (HD) treatment of patients with the terminal and most serious stage of chronic kidney disease (CKD) - end-stage kidney disease (ESKD). Oral supplementation with omega-3 fatty acids (ω-3FA) may help to prevent blockage of the vascular access by reducing the risk of thrombosis and stenosis. OBJECTIVES To evaluate the efficacy and safety of ω-3FA supplementation versus placebo or no treatment for maintaining vascular access patency in ESKD patients undergoing HD. SEARCH METHODS We searched the Cochrane Kidney and Transplant Register of Studies up to 23 July 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov. SELECTION CRITERIA Randomised controlled trials (RCTs) of omega-3 fatty acids versus placebo that assessed the patency of arteriovenous fistula (AVF) or arteriovenous graft (AVG) types of vascular access in ESKD patients. DATA COLLECTION AND ANALYSIS We assessed the risk of bias of each eligible study using the Cochrane Risk of Bias tool and made separate overall risk of bias judgments for the efficacy and safety outcomes. The certainty of evidence was assessed using the GRADE approach. The primary efficacy outcome was loss of vascular patency and the primary safety outcomes were occurrences of serious adverse events (e.g. death, hospitalisation, cardiovascular events, major bleeding). Secondary outcomes were the occurrence of non-serious adverse events (e.g. minor bleeding, gastrointestinal events and other adverse events). Efficacy effects were reported as risk ratios (RR) and safety effects as risk differences (RD) with 95% confidence intervals (CI). Studies were pooled separately by type of vascular access using a random-effects model. MAIN RESULTS Five studies (833 participants) were included; one was a very small pilot study of 7 participants. All studies compared oral ω-3FA supplements against placebo. Four studies enrolled participants with arteriovenous grafts (AVGs), and the other had participants with arteriovenous fistulas (AVFs). The risk of bias for both efficacy and safety outcomes was unclear for all studies, due mainly to incomplete reporting for allocation concealment and incompleteness of study follow-up.In AVF patients, ω-3FA supplementation probably makes little or no difference to the 12-month risk of patency loss (1 study, 536 participants: RR 1.01, 95% CI 0.84 to 1.21; moderate certainty evidence), risk of death (1 study, 567 participants: RD 0.00, 95% CI -0.03 to 0.02; moderate certainty evidence) and risk of hospitalisation (1 study, 567 participants: RD 0.00, 95% CI -0.08 to 0.08; low certainty evidence). There was no information on cardiovascular events and major bleeding.In AVG patients, it is very uncertain whether ω-3FA supplementation reduces the risk of patency loss within 6 months (2 studies, 41 participants: RR 0.91, 95% CI 0.36 to 2.28; very low certainty evidence) or 12 months (2 studies, 220 participants: RR 0.59, 95% CI 0.27 to 1.31; very low certainty evidence). ω-3FA supplementation may make little or no difference to the risk of death within 6 to 12 months in AVG patients (4 studies, 261 participants: RD 0.01, 95% CI -0.05 to 0.07; low certainty evidence). It is very uncertain if ω-3FA supplementation increases the risk of hospitalisation (3 studies, 65 participants: RD 0.08, 95% CI -0.11 to 0.28; very low certainty evidence), changes the risk of cardiovascular events (4 studies, 261 participants: RD -0.02, 95% CI -0.11 to 0.07; very low certainty evidence), or increases the risk of major bleeding (3 studies, 65 participants: RD 0.08, 95% CI -0.11 to 0.28; very low certainty evidence) within 6 to 12 months in AVG patients. There may be an increase in the risk of mild gastrointestinal adverse reactions (3 studies, 65 participants: RD 0.25, 95% CI 0.07 to 0.43; low certainty evidence) such as a sensation of bloatedness, gas or a fishy aftertaste. AUTHORS' CONCLUSIONS In CKD patients with an AVF, there is moderate certainty that ω-3FA supplementation makes little or no difference to preventing patency loss; and in patients with an AVG, it is very uncertain that ω-3FA supplementation prevents patency loss within 12 months.
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Affiliation(s)
- Ka‐Wai Tam
- Taipei Medical University‐Shuang Ho HospitalDivision of General Surgery, Department of Surgery291, Zhongzheng Road, Zhonghe DistrictNew Taipei CityTaiwan23561
- School of Medicine, College of Medicine, Taipei Medical UniversityDivision of General Surgery, Department of SurgeryTaipeiTaiwan
| | - Mei‐Yi Wu
- Taipei Medical University‐Shuang Ho HospitalDivision of Nephrology, Department of Internal Medicine291 Jhongjheng RdJhonghe DistrictNew Taipei CityTaiwan23561
- School of Medicine, College of Medicine, Taipei Medical UniversityDivision of Nephrology, Department of Internal MedicineTaipeiTaiwan
| | - Fahad Javaid Siddiqui
- The Hospital for Sick Children (SickKids)Centre for Global Child Health686 Bay StTorontoOntarioCanadaM5G 1X8
- Duke NUS Graduate Medical SchoolHealth Services & Systems Research ProgramSingaporeSingapore
| | - Edwin SY Chan
- Singapore Clinical Research InstituteCochrane SingaporeNanos Building #02‐0131 Biopolis WaySingaporeSingapore138669
| | - Yanan Zhu
- A*STARSingapore Institute of Clinical Sciences61 Compassvale Bow, #08‐21SingaporeSingapore544989
| | - Tazeen H Jafar
- Duke NUS Graduate Medical SchoolHealth Services & Systems Research ProgramSingaporeSingapore
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Kao Y, Loh E, Hsu C, Lin H, Huang C, Chou Y, Lien C, Tam K. Fluid Resuscitation in Patients With Severe Burns: A Meta-analysis of Randomized Controlled Trials. Acad Emerg Med 2018; 25:320-329. [PMID: 29024269 DOI: 10.1111/acem.13333] [Citation(s) in RCA: 5] [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] [Received: 05/17/2017] [Revised: 08/31/2017] [Accepted: 10/01/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Fluid resuscitation is the mainstay treatment to reconstitute intravascular volume and maintain end-organ perfusion in patients with severe burns. The use of a hyperosmotic or isoosmotic solution in fluid resuscitation to manage myocardial depression and increased capillary permeability during burn shock has been debated. We conducted a systematic review and meta-analysis to compare the efficacies of hyperosmotic and isoosmotic solutions in restoring hemodynamic stability after burn injuries. METHODS PubMed, Embase, Cochrane Library, Scopus, and ClinicalTrials.gov registry were searched. Randomized control trials evaluating the efficacy and safety of hyperosmotic and isoosmotic fluid resuscitation in patients with burn injuries were selected. Eligible trials were abstracted and assessed for the risk of bias by two reviewers and results of hemodynamic indicators in the included trials were analyzed. RESULTS Ten trials including 502 participants were published between 1983 and 2013. Compared with isoosmotic group, the hyperosmotic group exhibited a significant decrease in the fluid load (vol/% total body surface area [TBSA]/weight) at 24 hours postinjury, with a mean difference of -0.54 (95% confidence interval = -0.92 to -0.17). No differences were observed in the urine output, creatinine level, and mortality at 24 hours postinjury between groups. CONCLUSIONS Hyperosmotic fluid resuscitation appears to be an attractive choice for severe burns in terms of TBSA or burn depth. Further investigation is recommended before conclusive recommendation.
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Affiliation(s)
- Yuan Kao
- Department of Emergency Chi‐Mei Medical Hospital Tainan Taiwan
- Graduate Institute of Medical Sciences College of Health Science Chang Jung Christian University Tainan Taiwan
| | - El‐Wui Loh
- Center for Evidence‐Based Health Care Taipei Medical University‐Shuang Ho Hospital New Taipei City Taiwan
- Department of Medical Research Taipei Medical University‐Shuang Ho Hospital New Taipei City Taiwan
| | - Chien‐Chin Hsu
- Department of Emergency Chi‐Mei Medical Hospital Tainan Taiwan
- Department of Biotechnology Southern Taiwan University of Science and Technology Tainan Taiwan
| | - Hung‐Jung Lin
- Department of Emergency Chi‐Mei Medical Hospital Tainan Taiwan
- Department of Biotechnology Southern Taiwan University of Science and Technology Tainan Taiwan
- Department of Emergency Medicine Taipei Medical University Taipei Taiwan
| | - Chien‐Cheng Huang
- Department of Emergency Chi‐Mei Medical Hospital Tainan Taiwan
- Department of Occupational Medicine Chi‐Mei Medical Hospital Tainan Taiwan
- Department of Geriatrics and Gerontology Chi‐Mei Medical Hospital Tainan Taiwan
- Department of Child Care and Education Southern Taiwan University of Science and Technology Tainan Taiwan
- Department of Environmental and Occupational Health College of Medicine National Cheng Kung University Tainan Taiwan
| | - Yun‐Yun Chou
- Shared Decision Making Resource Center Taipei Medical University‐Shuang Ho Hospital New Taipei City Taiwan
| | - Chieh‐Chun Lien
- Department of Emergency Chi‐Mei Medical Hospital Tainan Taiwan
| | - Ka‐Wai Tam
- Center for Evidence‐Based Health Care Taipei Medical University‐Shuang Ho Hospital New Taipei City Taiwan
- Department of Medical Research Taipei Medical University‐Shuang Ho Hospital New Taipei City Taiwan
- Shared Decision Making Resource Center Taipei Medical University‐Shuang Ho Hospital New Taipei City Taiwan
- Division of General Surgery Department of Surgery Taipei Medical University‐Shuang Ho Hospital New Taipei City Taiwan
- Department of Surgery School of Medicine College of Medicine Taipei Medical University Taipei Taiwan
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Tam K, Tang I, Ho J, Yeung W, Lee CK, Ip P, Kwok J. A study of human neutrophil antigen genotype frequencies in Hong Kong. Transfus Med 2017; 28:310-318. [PMID: 29280200 DOI: 10.1111/tme.12494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [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: 03/01/2016] [Revised: 07/07/2017] [Accepted: 11/19/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND Alloantibodies against human neutrophil antigens (HNA) are associated with a variety of clinical conditions. Over the past decade, the allelic and genotypic frequencies of the five HNA systems have been evaluated. Although the HNA system is less polymorphic than human leukocyte antigens (HLA), significant differences in the genotypic and allele frequencies still exist in different populations, even those living in close proximity. OBJECTIVES To delineate HNA genotypic and allele frequencies to provide vital information on estimating the risk of HNA-associated diseases for our local population. METHODS Using a validated, in-house-developed assay, genotyping for HNA-1, HNA-3, HLA-4 and HNA-5 was performed on 300 samples from Chinese blood donors from Hong Kong. In addition, the frequency of the HNA-2 c.843A > T allele was also determined. RESULTS The allele frequencies of HNA-1a, -1b and -1c alleles were 67·8, 31·5 and 0%, respectively, whereas the frequencies of HNA-3a and HNA-3b were 71·0 and 29·0%, respectively. The frequencies of HNA-4a and -4b alleles were 99·5 and 0·5%, respectively, and for HNA-5a and -5b, alleles were 85·2 and 14·8%, respectively. Homozygotes for the HNA-2 c.843 TT variant were absent in our population, whereas only <4% of the population were c.843AT heterozygote carriers. CONCLUSIONS This is the first study to define HNA genotype and allele frequencies using a validated modified in-house PCR-SSP method in the Hong Kong Chinese blood donor population. Our approach provides a cost-effective assay for conducting routine HNA typing and facilitates the incorporation of these assays into routine clinical service. Our results are comparable with those reported in the Guangzhou Chinese population, but the allele frequencies in our Hong Kong Chinese population are significantly different from the reported European frequencies, confirming that a geographical difference exists for HNA allele frequencies.
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Affiliation(s)
- K Tam
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
| | - I Tang
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
| | - J Ho
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
| | - W Yeung
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
| | - C K Lee
- Hong Kong Red Cross Blood Transfusion Service, Kowloon, Hong Kong SAR, China
| | - P Ip
- Department of Paediatrics & Adolescent Medicine, University of Hong Kong, Hong Kong SAR, China
| | - J Kwok
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
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Flores R, Taioli E, Yankelevitz D, Yip R, Becker B, Jirapatnakul A, Reeves A, Schwartz R, Tam K, Henschke C. P2.16-022 Initiative for Early Lung Cancer Research on Treatment: Pilot Implementation. J Thorac Oncol 2017. [DOI: 10.1016/j.jtho.2017.09.1431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Grover S, Lowensteyn I, Wang J, Tam K, Grover S, Rempel P. CHALLENGES IN TREATING DYSLIPIDEMIA AMONG CANADIANS: FACTORS ASSOCIATED WITH SUB-OPTIMAL ADHERENCE TO MEDICATION. Can J Cardiol 2014. [DOI: 10.1016/j.cjca.2014.07.536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Schaff UY, Trott KA, Chase S, Tam K, Johns JL, Carlyon JA, Genetos DC, Walker NJ, Simon SI, Borjesson DL. Neutrophils exposed to A. phagocytophilum under shear stress fail to fully activate, polarize, and transmigrate across inflamed endothelium. Am J Physiol Cell Physiol 2010; 299:C87-96. [PMID: 20392928 DOI: 10.1152/ajpcell.00165.2009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Anaplasma phagocytophilum is an obligate intracellular bacterium that has evolved mechanisms to hijack polymorphonuclear neutrophil (PMN) receptors and signaling pathways to bind, infect, and multiply within the host cell. E-selectin is upregulated during inflammation and is a requisite endothelial receptor that supports PMN capture, rolling, and activation of integrin-mediated arrest. Ligands expressed by PMN that mediate binding to endothelium via E-selectin include sialyl Lewis x (sLe(x))-expressing ligands such as P-selectin glycoprotein ligand-1 (PSGL-1) and other glycolipids and glycoproteins. As A. phagocytophilum is capable of binding to sLe(x)-expressing ligands expressed on PMN, we hypothesized that acute bacterial adhesion to PMN would subsequently attenuate PMN recruitment during inflammation. We assessed the dynamics of PMN recruitment and migration under shear flow in the presence of a wild-type strain of A. phagocytophilum and compared it with a strain of bacteria that binds to PMN independent of PSGL-1. Acute bacterial engagement with PMN resulted in transient PMN arrest and minimal PMN polarization. Although the wild-type pathogen also signaled activation of beta2 integrins and elicited a mild intracellular calcium flux, downstream signals including PMN transmigration and phosphorylation of p38 mitogen-activated protein kinase (MAPK) were inhibited. The mutant strain bound less well to PMN and failed to activate beta2 integrins and induce a calcium flux but did result in decreased PMN arrest and polarization that may have been partially mediated by a suppression of p38 MAPK activation. This model suggests that A. phagocytophilum binding to PMN under shear flow during recruitment to inflamed endothelium interferes with normal tethering via E-selectin and navigational signaling of transendothelial migration.
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Affiliation(s)
- U Y Schaff
- Department of Biomedical Engineering, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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Tam K, Banwell K, Froiland D, Russell D, Kind K, Thompson J. 120. OXYGEN REGULATED GENE EXPRESSION IN MOUSE CUMULUS CELLS. Reprod Fertil Dev 2009. [DOI: 10.1071/srb09abs120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Hypoxia inducible factors (HIFs) are heterodimeric transcription factors that mediate the expression of a range of genes in response to low oxygen. Previously we showed that subsequent developmental outcomes were influenced by oxygen levels during in vitro maturation. The aim of the current study was to examine the effects of varying oxygen concentration during in vitro maturation of mouse COCs on expression of HIF target genes in the cumulus cells. I mmature COCs were collected from the ovaries of eCG-stimulated CBAB6F1 females (21 d) and cultured for 17-18 h under 2, 5 or 20% O2. Hyaluronidase-treated and recovered cumulus cells were collected and mRNA extracted for analysis. A microarray approach (Affymetrix 430_2) was used to identify genes in cumulus cells that were differentially expressed under varying oxygen concentrations (2, 5, 10 and 20%). This revealed 218 differentially expressed probes, of which 34 were up-regulated with decreasing oxygen levels. The great majority of these were classified as HIF-regulated genes. Specific analysis from real time RT-PCR of HIF regulated target genes Slc2a1, Ldha, Pgk1, Eno1, Ndrg1, Bnip3 were all significantly up-regulated (by at least 5–fold) when cells were cultured at 2% or 5% oxygen, when compared to 20% oxygen. Hif-1a mRNA decreased when cumulus cells were cultured in 2%, compared to 20% oxygen. This study demonstrates that cumulus cell gene expression is influenced by oxygen concentration, and suggests that these effects are mediated by the HIF transcription factors.
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Tam K, Russell D, Kind K, Thompson J. 435. Follicle differentiation and luteinisation in the mouse is associated with hypoxia inducible factor activity. Reprod Fertil Dev 2008. [DOI: 10.1071/srb08abs435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Hypoxia inducible factors (HIF) are transcription factors that mediate the response to hypoxic stress. Under hypoxic conditions, HIF is stabilised, translocates to the nucleus, and binds to the Hypoxia Response Elements (HRE) upstream of numerous target genes involved in angiogenesis and glycolysis, including Vegf, Glut-1 and Ldha. Little is known about the role of HIFs in regulating ovarian function. In rat granulosa cells, FSH stimulates HIF 1α via the PI3K/Akt pathway, demonstrating a role for HIFs during follicular development. In contrast, there is limited information regarding the role of HIFs during corpus luteum formation. In this study we investigated whether HIFs play a role in follicle differentiation and luteinisation. Prepubertal C57Bl6 females were stimulated with eCG (5 IU) followed 46 h later by hCG (5 IU). Mice were sacrificed at 0, 4, 8, 12, 16 and 24 h post hCG and granulosa cells were collected for Western analysis of HIF-1a protein. To investigate HIF activation in the ovary, a transgenic reporter mouse line was developed by lenti-viral incorporation of an HRE (4)-SV40-eGFP construct. Ovaries were collected from mice plugged day 1, 4 and 8 for CL analysis in vivo.A time- dependent increase of HIF 1α protein levels in granulosa cells, maximal around time of ovulation, was observed. Ovaries from cycling HRE-eGFP transgenic mice exhibited no eGFP in primordial, primary or preantral follicles. Upon antrum formation, eGFP was evident in occasional sections in antral follicles but HIF signalling was restricted within the theca. In contrast, corpora lutea on pregnancy day 1, 4 and 8 readily expressed eGFP and eGFP expression increases as luteinisation progresses.These results demonstrate that in vivo HIFs may play a role in folliculogenesis, but this is restricted to theca cells of antral follicles before hCG stimulation. Following hCG, maximal HIF activity is associated with the time of ovulation. In addition, HIF activity is maintained during luteinisation.
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Tam K, Kinsinger N, Ayala P, Qi F, Shi W, Myung N. Real-time monitoring of Streptococcus mutans biofilm formation using a quartz crystal microbalance. Caries Res 2007; 41:474-83. [PMID: 17851235 PMCID: PMC2820325 DOI: 10.1159/000108321] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Accepted: 05/11/2007] [Indexed: 11/19/2022] Open
Abstract
The ability of Streptococcus mutans, a well-known etiological agent in dental caries, to attach and form a biofilm is an important key to its virulence. The effects of various environmental factors (i.e. sucrose concentration, flow rate and temperature as well as genetic manipulations) on the capability of S. mutans (UA 140) to attach, form and detach were monitored in situ using quartz crystal microbalance. The biofilm growth rate was much slower than that of planktonic growth. Greater availability of sucrose contributed to biofilms with less lag time, lower doubling times and earlier detachment. Flow rate experiments showed that as the shear stress was reduced, the maximum mass accumulated also decreased. However, the detachment process was independent of shear force, perhaps indicative of quorum sensing. Increasing the incubation temperature from 37 to 40 degrees C extended the lag period and inhibited the ability of the biofilm to attach readily. Absence of either the ciaH, luxS, gtfB or gtfC genes also greatly affected the ability of the S. mutans to adhere to a surface in comparison to the wild type. Quartz crystal microbalance results indicate that the gtfC gene possibly has a greater contribution to biofilm attachment than the gtfB gene, that the presence of the luxS gene is critical for attachment and that the ciaH gene primarily affects the initial reversible attachment of the biofilm.
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Affiliation(s)
- K. Tam
- Department of Chemical and Environmental Engineering, University of California-Riverside, Riverside, Calif., Los Angeles, Calif., USA
| | - N. Kinsinger
- Department of Chemical and Environmental Engineering, University of California-Riverside, Riverside, Calif., Los Angeles, Calif., USA
| | - P. Ayala
- Department of Chemical and Environmental Engineering, University of California-Riverside, Riverside, Calif., Los Angeles, Calif., USA
| | - F. Qi
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, Calif., USA
| | - W. Shi
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, Calif., USA
| | - N.V. Myung
- Department of Chemical and Environmental Engineering, University of California-Riverside, Riverside, Calif., Los Angeles, Calif., USA
- *Dr. N.V. Myung, Department of Chemical and Environmental Engineering, University of California, Bourns Hall, Riverside, CA 92521 (USA), Tel. +1 951 827 7710, Fax +1 951 827 5696, E-Mail
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15
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Kreth J, Hagerman E, Tam K, Merritt J, Wong DTW, Wu BM, Myung NV, Shi W, Qi F. Quantitative analyses of Streptococcus mutans biofilms with quartz crystal microbalance, microjet impingement and confocal microscopy. ACTA ACUST UNITED AC 2005; 1:277-284. [PMID: 16429589 PMCID: PMC1307168 DOI: 10.1017/s1479050504001516] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Microbial biofilm formation can be influenced by many physiological and genetic factors. The conventional microtiter plate assay provides useful but limited information about biofilm formation. With the fast expansion of the biofilm research field, there are urgent needs for more informative techniques to quantify the major parameters of a biofilm, such as adhesive strength and total biomass. It would be even more ideal if these measurements could be conducted in a real-time, non-invasive manner. In this study, we used quartz crystal microbalance (QCM) and microjet impingement (MJI) to measure total biomass and adhesive strength, respectively, of S. mutans biofilms formed under different sucrose concentrations. In conjunction with confocal laser scanning microscopy (CLSM) and the COMSTAT software, we show that sucrose concentration affects the biofilm strength, total biomass, and architecture in both qualitative and quantitative manners. Our data correlate well with previous observations about the effect of sucrose on the adherence of S. mutans to the tooth surface, and demonstrate that QCM is a useful tool for studying the kinetics of biofilm formation in real time and that MJI is a sensitive, easy-to-use device to measure the adhesive strength of a biofilm.
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Affiliation(s)
- J. Kreth
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - E. Hagerman
- Department of Bioengineering, UCLA School of Engineering and Applied Sciences, Los Angeles, CA 90095, USA
| | - K. Tam
- Department of Chemical and Environmental Engineering. University of California, Riverside, CA 92521, USA
| | - J. Merritt
- UCLA Molecular Biology Institute, Los Angeles, CA 90025, USA
| | - D. T. W. Wong
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - B. M. Wu
- Department of Bioengineering, UCLA School of Engineering and Applied Sciences, Los Angeles, CA 90095, USA
- Department of Materials Science and Engineering, UCLA School of Engineering and Applied Sciences, Los Angeles, CA 90095, USA
| | - N. V. Myung
- Department of Chemical and Environmental Engineering. University of California, Riverside, CA 92521, USA
| | - W. Shi
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA
- UCLA Molecular Biology Institute, Los Angeles, CA 90025, USA
| | - F. Qi
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA
- * Corresponding author: Dr F. Qi, Department of Oral Biology and Medicine, UCLA School of Dentistry, PO Box 951668, Los Angeles, CA 90095-1668, USA, T 1 310 825-0203, F 1 310 794-7109, E
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Castro C, Tharmaratnam U, Tam K, Brockhurst N, Tureanu L, Windrim R, Mowbray M. PATIENT CONTROLLED ANALGESIA USING FENTANYL FOR SECOND TRIMESTER LABOR ANALGESIA. VARYING BOLUS DOSE AND LOCKOUT INTERVAL. Anesthesiology 2002. [DOI: 10.1097/00000542-200204001-00059] [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: 11/25/2022]
Affiliation(s)
- C. Castro
- Anesthesia, Mount Sinai Hospital, Toronto, ON, Canada
| | | | - K. Tam
- Nursing, Mount Sinai Hospital, Toronto, ON, Canada
| | | | - L. Tureanu
- Anesthesia, Mount Sinai Hospital, Toronto, ON, Canada
| | - R. Windrim
- OB/GYN, Mount Sinai Hospital, Toronto, ON, Canada
| | - M. Mowbray
- Nursing, Mount Sinai Hospital, Toronto, ON, Canada
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Ng JS, Fan DS, Young AL, Yip NK, Tam K, Kwok AK, Lam DS. Ocular hypertensive response to topical dexamethasone in children: a dose-dependent phenomenon. Ophthalmology 2000; 107:2097-100. [PMID: 11054340 DOI: 10.1016/s0161-6420(00)00357-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [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: 11/21/2022] Open
Abstract
OBJECTIVE To investigate the ocular-hypertensive response to different dosages of topical dexamethasone eye drops in Chinese children. DESIGN Prospective, randomized clinical trial. PARTICIPANTS Thirty-one consecutive children undergoing bilateral strabismus surgery. INTERVENTION Topical dexamethasone (0.1%) was administered to children undergoing bilateral strabismus surgery. They were all less than 10 years of age. One eye was randomized to receive a regimen of four times daily, and another received a twice daily regimen. Intraocular pressure (IOP) was serially measured in the postoperative period for 4 weeks or more. Topical steroids were discontinued if IOP was 30 mmHg or more. MAIN OUTCOME MEASURES Intraocular pressure was measured on the day before the surgery, on postoperative days 1, 3, 5, 8, 12, 15, 22, 29, and 2 weeks thereafter until the IOP reached preoperative levels. Peak IOP, IOP net increase, and time to reach an IOP more than 20 mmHg in the two study groups were analyzed. RESULTS A total of 31 patients (20 male, 11 female) were examined. The mean age was 5.8 +/- 2.0 years (range, 2-10 years). Preoperative IOP in groups treated twice daily and four times daily were similar. After topical dexamethasone treatment, both groups showed a significant rise in peak IOP compared with preoperative values (twice daily, 25.2 +/- 6.8 mmHg vs. 14.3 +/- 2.4 mmHg, P < 0.001; four times daily, 28.7 +/- 6.9 mmHg vs. 14.3 +/- 2.9 mmHg, P < 0.001). The peak IOP was significantly higher in the four times daily group (P < 0.001), as was the net increase in IOP (twice daily, 10.9 +/- 5.8 mmHg vs. four times daily, 14.5 +/- 6.4 mmHg; P < 0.001). There was no difference in time for both groups to achieve the peak IOP, but the time to exceed its upper normal value (20 mmHg) was shorter in the four times daily group (twice daily, 12.3 +/- 9.1 days vs. four times daily, 10.0 +/- 7.4 days; P < 0.05). CONCLUSIONS In children treated with topical dexamethasone, ocular hypertension occurs in a dose-dependent manner. Children in the four times daily group had a quicker onset and more severe ocular hypertensive response than the twice daily group. Nevertheless, even the twice daily regimen produced significant IOP rise, suggesting that dexamethasone use in children should be avoided if possible, and it would be desirable to monitor the IOP twice weekly when it is administered to children.
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Affiliation(s)
- J S Ng
- Department of Ophthalmology, Alice Ho Miu Ling Nethersole Hospital, Tai Po, New Territories, Hong Kong
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Bowen KA, Tam K, Colombini M. Evidence for titratable gating charges controlling the voltage dependence of the outer mitochondrial membrane channel, VDAC. J Membr Biol 1985; 86:51-9. [PMID: 2413210 DOI: 10.1007/bf01871610] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A voltage-dependent anion-selective channel, VDAC, is found in outer mitochondrial membranes. VDAC's conductance is known to decrease as the transmembrane voltage is increased in either the positive or negative direction. Charged groups on the channel may be responsible for this voltage dependence by allowing the channel to respond to an applied electric field. If so, then neutralization of these charges would eliminate the voltage dependence. Channels in planar lipid bilayers which behaved normally at pH 6 lost much of their voltage dependence at high pH. Raising the pH reduced the steepness of the voltage dependence and raised the voltage needed to close half the channels. In contrast, the energy difference between the open and closed state in the absence of a field was changed very little by the elevated pH. The groups being titrated had an apparent pK of 10.6. From the pK and chemical modification, lysine epsilon amino groups are the most likely candidates responsible for VDAC's ability to respond to an applied electric field.
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