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Nguyen DK, OLeary S, Gadalla MA, Wang R, Li W, Song Z, Roberts B, Alvino H, Tremellen KP, Mol BW. P–728 Can in couples with unexplained infertility the use of a prediction model to triage assisted reproduction technology save costs? Hum Reprod 2021. [DOI: 10.1093/humrep/deab130.727] [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: 11/12/2022] Open
Abstract
Abstract
Study question
Can in couples with unexplained infertility a prognosis-tailored management strategy, that delays treatment if natural conception prospects are good, reduce costs without affecting live-birth rate?
Summary answer
In couples with unexplained infertility, use of a prognostic tool for natural conception followed by expectant management in good-prognosis couples is cost-effective.
What is known already
Few countries have guidelines for the assessment of the likelihood of natural conception to determine access to publicly funded ART. In the Netherlands and New-Zealand, couples with unexplained infertility who have a good prognosis for natural conception are encouraged to delay starting ART. However, the cost-effectiveness of this prognosis-tailored treatment strategy has not been determined.
Study design, size, duration
We studied couples with unexplained infertility to compare a prognosis-tailored strategy to care-as-usual. In the prognosis-tailored strategy, couples were assessed using Hunault’s prediction model. In good-prognosis couples (12-months natural conception >40%), outcomes without ART were modelled by censoring observations after start of ART. We then assumed that poor-prognosis couples (<40% natural conception) were treated, while good-prognosis couples delayed the start of treatment for 12 months. Data for the care-as-usual model were based on real observations.
Participants/materials, setting, methods
We studied 272 couples with unexplained infertility. Costs of in vitro fertilisation (IVF) and intra-uterine insemination (IUI) were calculated based on the out-of-pocket costs and Australian Medicare costs. In a cost-effectiveness model, we compared costs and effects of both strategies.
Main results and the role of chance
The prognostic model classified 272 couples with unexplained infertility as favourable (N = 107 (39.3%) or unfavourable prognosis (N = 165 (60.7%)) for natural conception. In the prognosis-tailored strategy, the cumulative live-birth rate was 71.1% (95% CI 64.7% - 76.4%) while the number of ART cycles was 393 (353 IVF; 40 IUI). In care-as-usual strategy, the cumulative conception rate leading to live-birth for the cohort of 272 couples, who underwent a total of 398 IVF cycles and 48 IUI cycles, was 72.1% (95% CI 65.7% - 77.4%). Mean time to conception leading to live birth was 388 days in the prognosis-tailored strategy and 419 days in the care-as-usual strategy.
This translated for the 272 couples into potential savings of 45 IVF cycles and eight IUI cycles, which cost a total of AUD$ 125,817 for out-of-pocket and AUD$ 264,497 for Australian Medicare. The average cost savings per couple was AUD$ 1,435 (out-of-pocket AUD$ 463 per couple and Australian Medicare AUD$ 962 per couple). The incremental cost-effectiveness ratio, which was calculated as the total costs per additional live-births, was AUD$ 143,497 per additional live birth.
Limitations, reasons for caution
This study was limited to couples at a single IVF clinic. The modelling was also based on several key assumptions, particularly the number of fresh and frozen embryo transfer cycles for each couple.
Wider implications of the findings: Our results show that in couples with unexplained infertility the use of a prognostic model guiding the start of an IVF-treatment reduces costs without compromising live birth rates.
Trial registration number
Not applicable
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Affiliation(s)
- D K Nguyen
- Robinson Research Institute, The University of Adelaide, Adelaide, Australia
| | - S OLeary
- Robinson Research Institute, The University of Adelaide, Adelaide, Australia
| | - M A Gadalla
- Women’s Health Hospital, Department of Obstetrics and Gynaecology- Faculty of Medicine- Assuit University, Assuit, Egypt
| | - R Wang
- Department of Obstetrics and Gynaecology, Monash University, Victoria, Australia
| | - W Li
- Department of Obstetrics and Gynaecology, Monash University, Victoria, Australia
| | - Z Song
- Faculty of Medicine- Nursing and Health Sciences, Monash University, Victoria, Australia
| | - B Roberts
- Repromed IVF Adelaide, Dulwich, South Australia, Australia
| | - H Alvino
- Repromed IVF Adelaide, Dulwich, South Australia, Australia
| | - K P Tremellen
- Repromed IVF Adelaide, Dulwich, South Australia, Australia
| | - B W Mol
- Department of Obstetrics and Gynaecology, Monash University, Victoria, Australia
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Hammoud A, Chhin D, Nguyen DK, Sawan M. A new molecular imprinted PEDOT glassy carbon electrode for carbamazepine detection. Biosens Bioelectron 2021; 180:113089. [PMID: 33662846 DOI: 10.1016/j.bios.2021.113089] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [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: 02/18/2020] [Revised: 02/07/2021] [Accepted: 02/10/2021] [Indexed: 11/17/2022]
Abstract
An electrochemical sensor for the detection of carbamazepine was fabricated by the electropolymerization of PEDOT on glassy carbon electrodes. Molecular imprinted polymer sites were synthesized by cyclic voltammetry on the electrodes' surfaces providing high selectivity and sensitivity towards carbamazepine molecules. Scanning electron microscopy validated the formation of the polymer. Extraction of carbamazepine from the polymer was performed by immersion in acetonitrile and validated by ultraviolet-visible spectroscopy along with cyclic voltammetry experiments comparing pre- and post-template extraction data. Further cyclic voltammetry and square-wave voltammetry tests aided in characterizing the electrodes' response to carbamazepine concentration in PBS solution with [Fe(CN)6]3-/4- as a redox pair/mediator. The limits of detection and quantification were found to be 0.98 x 10-3 M and 2.97 x 10-3 M respectively. The biosensor was highly sensitive to carbamazepine molecules in comparison to non-imprinted electrodes, simple to construct and easy to operate.
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Affiliation(s)
- A Hammoud
- Department of Electrical Engineering, Polytechnique Montréal, Montréal, QC, Canada.
| | - D Chhin
- Département de Chimie, UQAM, Montréal, QC, Canada
| | - D K Nguyen
- Centre Hospitalier de L'Université de Montréal, Université de Montréal, Montréal, QC, Canada
| | - M Sawan
- Department of Electrical Engineering, Polytechnique Montréal, Montréal, QC, Canada; School of Engineering, Westlake University, And Westlake Institute for Advanced Study, Zhejiang, China
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Gagliano L, Assi EB, Toffa DH, Nguyen DK, Sawan M. Unsupervised Clustering of HRV Features Reveals Preictal Changes in Human Epilepsy. Annu Int Conf IEEE Eng Med Biol Soc 2020; 2020:698-701. [PMID: 33018083 DOI: 10.1109/embc44109.2020.9175739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Over a third of patients suffering from epilepsy continue to live with recurrent disabling seizures and would greatly benefit from personalized seizure forecasting. While electroencephalography (EEG) remains most popular for studying subject-specific epileptic precursors, dysfunctions of the autonomous nervous system, notably cardiac activity measured in heart rate variability (HRV), have also been associated with epileptic seizures. This work proposes an unsupervised clustering technique which aims to automatically identify preictal HRV changes in 9 patients who underwent simultaneous electrocardiography (ECG) and intracranial EEG presurgical monitoring at the University of Montreal Hospital Center. A 2-class k-means clustering combined with a quantitative preictal HRV change detection technique were adopted in a subject- and seizure-specific manner. Results indicate inter and intra-patient variability in preictal HRV changes (between 3.5 and 6.5 min before seizure onset) and a statistically significant negative correlation between the time of change in HRV state and the duration of seizures (p<0.05). The presented findings show promise for new avenues of research regarding multimodal seizure prediction and unsupervised preictal time assessment.Clinical Relevance- This study proposed an unsupervised technique for quantitatively identifying preictal HRV changes which can be eventually used to implement an ECG-based seizure forecasting algorithm.
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Janssen KM, Nieves-Robbins NM, Echelmeier TB, Nguyen DK, Baker KC. Could Nonenhanced Computer Tomography Suffice as the Imaging Study of Choice for the Screening of Asymptomatic Microscopic Hematuria? Urology 2018; 120:36-41. [PMID: 30099126 DOI: 10.1016/j.urology.2018.07.013] [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: 12/13/2017] [Revised: 07/02/2018] [Accepted: 07/06/2018] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To compare the diagnostic accuracy of the noncontrast and contrast-enhanced phases of computed tomographic urography for detection of upper urinary tract findings in adults undergoing initial evaluation of newly diagnosed asymptomatic microscopic hematuria to determine if less-intensive noncontrast imaging has the potential to become a suitable imaging alternative in the work-up of this common condition. MATERIALS AND METHODS Retrospective review from 2010-2015 for adults who underwent computed tomographic urography for initial evaluation of asymptomatic microscopic hematuria. Three nonblinded physicians independently categorized the upper urinary tract findings described in the computed tomography reports into one of three groups: normal, benign, or suspicious for malignancy. The noncontrast images of a randomized portion of the studies categorized as normal and all studies categorized as suspicious and benign were submitted to two blinded radiologists who independently classified each study into one of the aforementioned categories. RESULTS The noncontrast images for 475 subjects were blindly reviewed. When compared to the computed tomographic urography reports, the negative predictive values of noncontrast images were 97.25% and 94.92% for radiologist 1 and radiologist 2, respectively, with an associated specificity of 88.6% and 97.95%. Of the 5 true upper tract malignancies, both blinded radiologists correctly identified 4 of the 5. CONCLUSION Contrast imaging added little diagnostic value when compared with noncontrast imaging for most subjects undergoing initial evaluation for asymptomatic microscopic hematuria. Less-intensive imaging with nonenhanced computed tomography could reduce the nontrivial risks associated with multiphasic contrast imaging but further work is necessary to identify risk-stratifying criteria.
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Affiliation(s)
| | - Neris M Nieves-Robbins
- Deputy Chief Medical Informatics Officer, Headquarters, Department of the Army (Office of the Surgeon General) Falls, Church, VA; General Diagnostic and Pediatric Radiologist, Fort Belvoir Community Hospital, Fort Belvoir, VA
| | - Trevor B Echelmeier
- General Diagnostic and Pediatric Radiologist, Fort Belvoir Community Hospital, Fort Belvoir, VA
| | - David K Nguyen
- General Diagnostic and Pediatric Radiologist, Fort Belvoir Community Hospital, Fort Belvoir, VA
| | - Karen C Baker
- Madigan Army Medical Center, Urology Department, Tacoma WA; Department of Surgery, Division of Urology, Duke University Medical Center, Durham NC
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Abstract
The insula is a deep cortical structure sharing extensive synaptic connections with a variety of brain regions, including several frontal, temporal, and parietal structures. The identification of the insular connectivity network is obviously valuable for understanding a number of cognitive processes, but also for understanding epilepsy since insular seizures involve a number of remote brain regions. Ultimately, knowledge of the structure and causal relationships within the epileptic networks associated with insular cortex epilepsy can offer deeper insights into this relatively neglected type of epilepsy enabling the refining of the clinical approach in managing patients affected by it. In the present chapter, we first review the multimodal noninvasive tests performed during the presurgical evaluation of epileptic patients with drug refractory focal epilepsy, with particular emphasis on their value for the detection of insular cortex epilepsy. Second, we review the emerging multimodal investigation techniques in the field of epilepsy, that aim to (1) enhance the detection of insular cortex epilepsy and (2) unveil the architecture and causal relationships within epileptic networks. We summarize the results of these approaches with emphasis on the specific case of insular cortex epilepsy.
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Affiliation(s)
- Y Zerouali
- Research Centre, Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada; Ecole Polytechnique de Montréal, Montreal, QC, Canada
| | - J Ghaziri
- Research Centre, Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada
| | - D K Nguyen
- Research Centre, Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada; CHUM-Hôpital Notre-Dame, Montreal, QC, Canada.
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Affiliation(s)
- David K Nguyen
- Department of Surgery, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Parviz K Amid
- Department of Surgery, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA; Lichtenstein Amid Hernia Clinic at UCLA, 1304 15th Street, Suite 102, Santa Monica, CA 90404, USA
| | - David C Chen
- Department of Surgery, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA; Lichtenstein Amid Hernia Clinic at UCLA, 1304 15th Street, Suite 102, Santa Monica, CA 90404, USA.
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Abstract
BACKGROUND Electrical stimulation used for brain mapping in the postero-superior insula can evoke pain. The effects of prolonged high frequency insular stimulation on pain thresholds are unknown. OBJECTIVE/HYPOTHESIS Prolonged high frequency insular stimulation, by virtue of its inhibitory properties on networks, could decrease thermal nociception. METHODS Epileptic subjects had electrodes implanted in the insular cortex for the purpose of epileptic focus resection. Thermal and pressure nociceptive thresholds were tested bilaterally on the forearm on two consecutive days. Randomly assigned double-blind high frequency (150 Hz) insular stimulation took place for 10 min before pain testing either on the first day or on the second day. RESULTS Six subjects (three females; mean age of 35 years) were included. Insular stimulation increased heat pain threshold on the ipsilateral (p = 0.003; n = 6) and contralateral sides (p = 0.047; n = 6). Differences in cold pain threshold did not reach statistical significance (ipsilateral: p = 0.341, contralateral: p = 0.143; n = 6), but one subject had a profound decrease in both heat and cold pain responses. Pressure pain threshold was not modified by insular stimulation (ipsilateral: p = 0.1123; contralateral: p = 0.1192; n = 6). Two of the three subjects who had a postero-superior operculo-insulectomy developed central pain with contralateral thermal nociceptive deficit. CONCLUSIONS High frequency inhibitory postero-superior insular stimulation may have the potential to decrease thermal nociception. Together with previous studies, our data support the notion that the integrity of this brain region is necessary for thermal but not pressure nociceptive processing.
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Affiliation(s)
- D J Denis
- Division of Neurosurgery, Department of Surgery, Centre Hospitalier de l'Université de Montréal (Hôpital Notre-Dame), Canada
| | - R Marouf
- Department of Neuroscience, Université de Montréal, Canada
- Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Université de Montréal, Canada
| | - P Rainville
- Department of Neuroscience, Université de Montréal, Canada
- Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Université de Montréal, Canada
- Department of Stomatology, Université de Montréal, Canada
- Centre de recherche en neuropsychologie et cognition (CERNEC), Université de Montréal, Canada
- Groupe de recherche sur le système nerveux central (GRSNC), Université de Montréal, Canada
| | - A Bouthillier
- Division of Neurosurgery, Department of Surgery, Centre Hospitalier de l'Université de Montréal (Hôpital Notre-Dame), Canada
| | - D K Nguyen
- Department of Neuroscience, Université de Montréal, Canada
- Division of Neurology, Department of Medicine, Centre Hospitalier Université de Montréal (Hôpital Notre-Dame), Canada
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Hempel S, Maggard-Gibbons M, Nguyen DK, Dawes AJ, Miake-Lye I, Beroes JM, Booth MJ, Miles JNV, Shanman R, Shekelle PG. Wrong-Site Surgery, Retained Surgical Items, and Surgical Fires : A Systematic Review of Surgical Never Events. JAMA Surg 2015; 150:796-805. [PMID: 26061125 DOI: 10.1001/jamasurg.2015.0301] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Serious, preventable surgical events, termed never events, continue to occur despite considerable patient safety efforts. OBJECTIVE To examine the incidence and root causes of and interventions to prevent wrong-site surgery, retained surgical items, and surgical fires in the era after the implementation of the Universal Protocol in 2004. DATA SOURCES We searched 9 electronic databases for entries from 2004 through June 30, 2014, screened references, and consulted experts. STUDY SELECTION Two independent reviewers identified relevant publications in June 2014. DATA EXTRACTION AND SYNTHESIS One reviewer used a standardized form to extract data and a second reviewer checked the data. Strength of evidence was established by the review team. Data extraction was completed in January 2015. MAIN OUTCOMES AND MEASURES Incidence of wrong-site surgery, retained surgical items, and surgical fires. RESULTS We found 138 empirical studies that met our inclusion criteria. Incidence estimates for wrong-site surgery in US settings varied by data source and procedure (median estimate, 0.09 events per 10,000 surgical procedures). The median estimate for retained surgical items was 1.32 events per 10,000 procedures, but estimates varied by item and procedure. The per-procedure surgical fire incidence is unknown. A frequently reported root cause was inadequate communication. Methodologic challenges associated with investigating changes in rare events limit the conclusions of 78 intervention evaluations. Limited evidence supported the Universal Protocol (5 studies), education (4 studies), and team training (4 studies) interventions to prevent wrong-site surgery. Limited evidence exists to prevent retained surgical items by using data-matrix-coded sponge-counting systems (5 pertinent studies). Evidence for preventing surgical fires was insufficient, and intervention effects were not estimable. CONCLUSIONS AND RELEVANCE Current estimates for wrong-site surgery and retained surgical items are 1 event per 100,000 and 1 event per 10,000 procedures, respectively, but the precision is uncertain, and the per-procedure prevalence of surgical fires is not known. Root-cause analyses suggest the need for improved communication. Despite promising approaches and global Universal Protocol evaluations, empirical evidence for interventions is limited.
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Affiliation(s)
- Susanne Hempel
- Southern California Evidence-Based Practice Center, RAND Corporation, Santa Monica
| | - Melinda Maggard-Gibbons
- Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California3Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles
| | - David K Nguyen
- Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles
| | - Aaron J Dawes
- Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California4Robert Wood Johnson Clinical Scholars Program, University of California, Los Angeles
| | - Isomi Miake-Lye
- Evidence-Based Synthesis Program (ESP) Center, West Los Angeles Veterans Affairs Medical Center, Los Angeles, California
| | - Jessica M Beroes
- Evidence-Based Synthesis Program (ESP) Center, West Los Angeles Veterans Affairs Medical Center, Los Angeles, California
| | - Marika J Booth
- Southern California Evidence-Based Practice Center, RAND Corporation, Santa Monica
| | | | - Roberta Shanman
- Southern California Evidence-Based Practice Center, RAND Corporation, Santa Monica
| | - Paul G Shekelle
- Evidence-Based Synthesis Program (ESP) Center, West Los Angeles Veterans Affairs Medical Center, Los Angeles, California
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Sacks GD, Shannon EM, Dawes AJ, Rollo JC, Nguyen DK, Russell MM, Ko CY, Maggard-Gibbons MA. Teamwork, communication and safety climate: a systematic review of interventions to improve surgical culture. BMJ Qual Saf 2015; 24:458-67. [DOI: 10.1136/bmjqs-2014-003764] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 05/05/2015] [Indexed: 01/12/2023]
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Dawes AJ, Hemmelgarn M, Nguyen DK, Sacks GD, Clayton S, Cope J, Ganz PA, Maggard-Gibbons M. Are primary care providers prepared to care for survivors of breast cancer in the safety net? Cancer 2015; 121:1249-56. [PMID: 25536301 PMCID: PMC4393343 DOI: 10.1002/cncr.29201] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [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: 10/01/2014] [Revised: 11/10/2014] [Accepted: 11/17/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND With the growing number of survivors of breast cancer outpacing the capacity of oncology providers, there is pressure to transition patients back to primary care. Primary care providers (PCPs) working in safety-net settings may have less experience treating survivors, and little is known about their knowledge and views on survivorship care. The current study was performed to determine the knowledge, attitudes, and confidence of PCPs in the safety net at delivering care to survivors of breast cancer. METHODS A modified version of the National Cancer Institute's Survey of Physician Attitudes Regarding Care of Cancer Survivors was given to providers at 2 county hospitals and 5 associated clinics (59 providers). Focus groups were held to understand barriers to survivorship care. RESULTS Although the majority of providers believed PCPs have the skills necessary to provide cancer-related follow-up, the vast majority were not comfortable providing these services themselves. Providers were adherent to American Society of Clinical Oncology recommendations for mammography (98%) and physical examination (87%); less than one-third were guideline-concordant for laboratory testing and only 6 providers (10%) met all recommendations. PCPs universally requested additional training on clinical guidelines and the provision of written survivorship care plans before transfer. Concerns voiced in qualitative sessions included unfamiliarity with the management of endocrine therapy and confusion regarding who would be responsible for certain aspects of care. CONCLUSIONS Safety-net providers currently lack knowledge of and confidence in providing survivorship care to patients with breast cancer. Opportunities exist for additional training in evidence-based guidelines and improved coordination of care between PCPs and oncology specialists.
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Affiliation(s)
- Aaron J. Dawes
- Department of Surgery, David Geffen School of Medicine, UCLA, Los Angeles, CA
- VA Greater Los Angeles Healthcare System, Los Angeles, CA
- RWJF Clinical Scholars Program, UCLA, Los Angeles, CA
| | | | - David K. Nguyen
- Department of Surgery, David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Greg D. Sacks
- Department of Surgery, David Geffen School of Medicine, UCLA, Los Angeles, CA
- RWJF Clinical Scholars Program, UCLA, Los Angeles, CA
| | - Sheilah Clayton
- Martin Luther King, Jr./Charles R. Drew University Medical Center, Los Angeles, CA
| | | | - Patricia A. Ganz
- Department of Medicine, David Geffen School of Medicine UCLA, Los Angeles, CA
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA
| | - Melinda Maggard-Gibbons
- Department of Surgery, David Geffen School of Medicine, UCLA, Los Angeles, CA
- VA Greater Los Angeles Healthcare System, Los Angeles, CA
- Olive View/UCLA Medical Center, Sylmar, CA
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Dawes AJ, Louie R, Nguyen DK, Maggard-Gibbons M, Parikh P, Ettner SL, Ko CY, Zingmond DS. The impact of continuous Medicaid enrollment on diagnosis, treatment, and survival in six surgical cancers. Health Serv Res 2014; 49:1787-811. [PMID: 25256223 PMCID: PMC4254125 DOI: 10.1111/1475-6773.12237] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE To examine the effect of Medicaid enrollment on the diagnosis, treatment, and survival of six surgically relevant cancers among poor and underserved Californians. DATA SOURCES California Cancer Registry (CCR), California's Patient Discharge Database (PDD), and state Medicaid enrollment files between 2002 and 2008. STUDY DESIGN We linked clinical and administrative records to differentiate patients continuously enrolled in Medicaid from those receiving coverage at the time of their cancer diagnosis. We developed multivariate logistic regression models to predict death within 1 year for each cancer after controlling for sociodemographic and clinical variables. DATA COLLECTION/EXTRACTION METHODS All incident cases of six cancers (colon, esophageal, lung, pancreas, stomach, and ovarian) were identified from CCR. CCR records were linked to hospitalizations (PDD) and monthly Medicaid enrollment. PRINCIPAL FINDINGS Continuous enrollment in Medicaid for at least 6 months prior to diagnosis improves survival in three surgically relevant cancers. Discontinuous Medicaid patients have higher stage tumors, undergo fewer definitive operations, and are more likely to die even after risk adjustment. CONCLUSIONS Expansion of continuous insurance coverage under the Affordable Care Act is likely to improve both access and clinical outcomes for cancer patients in California.
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Affiliation(s)
- Aaron J Dawes
- Department of Surgery, David Geffen School of Medicine at the University of CaliforniaLos Angeles, 757 Westwood Plaza, B711, Los Angeles, CA 90095
- Robert Wood Johnson Clinical Scholars Program, University of CaliforniaLos Angeles, CAVA Greater Los Angeles Healthcare SystemLos Angeles, CA
| | - Rachel Louie
- Department of Medicine, Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at the University of CaliforniaLos Angeles, CA
| | - David K Nguyen
- Department of Surgery, David Geffen School of Medicine at the University of CaliforniaLos Angeles, CA
| | - Melinda Maggard-Gibbons
- Department of Surgery, David Geffen School of Medicine at the University of CaliforniaLos AngelesVA Greater Los Angeles Healthcare SystemLos Angeles, CA
| | - Punam Parikh
- Department of Medicine, Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at the University of CaliforniaLos Angeles, CA
- Department of Surgery, David Geffen School of Medicine at the University of CaliforniaLos Angeles, CA
| | - Susan L Ettner
- Department of Medicine, Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at the University of CaliforniaLos Angeles, CA
- Department of Health Policy and Management, Jonathan and Karin Fielding School of Public Health at the University of CaliforniaLos Angeles, CA
| | - Clifford Y Ko
- Department of Surgery, David Geffen School of Medicine at the University of CaliforniaLos AngelesVA Greater Los Angeles Healthcare SystemLos Angeles, CA
| | - David S Zingmond
- Department of Medicine, Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at the University of CaliforniaLos Angeles, CA
- Department of Surgery, David Geffen School of Medicine at the University of CaliforniaLos Angeles, CA
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Chevrier MC, Bard C, Guilbert F, Nguyen DK. Structural abnormalities in patients with insular/peri-insular epilepsy: spectrum, frequency, and pharmacoresistance. AJNR Am J Neuroradiol 2013; 34:2152-6. [PMID: 23811976 DOI: 10.3174/ajnr.a3636] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARY Between 2002 and 2010, a total of 48 patients were seen at our epilepsy clinic with insular/peri-insular cortex epilepsy. Review of their MR imaging scans revealed a neoplastic lesion in 27% of patients, a malformation of cortical development in 21%, a vascular malformation in 19%, and atrophy/gliosis from an acquired insult in 17%. MR imaging results were normal in 4 patients. Other miscellaneous findings included a case of Rasmussen encephalitis, a nonspecific insular millimetric T2 signal abnormality, a neuroepithelial cyst, and hippocampal sclerosis without MR imaging evidence of dual insular pathologic features (despite depth electrode-proven insular seizures). Refractoriness to antiepileptic drug treatment was present in 56% of patients: 100% for patients with malformations of cortical development (1.0; 95% CI, 0.72-1.0), 50.0% (0.5; 95% CI, 0.21-0.78) in the presence of atrophy/gliosis from acquired insults, 39% (0.39; 95% CI, 0.14-0.68) for neoplastic lesions, and 22.2% (0.22; 95% CI, 0.06-0.55) for vascular malformations.
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Abstract
BACKGROUND Gastric cancer is an aggressive disease, and overall changes in incidence rates have been noted. There are conflicting data on whether young patients have worse outcomes than older patients; the roles of tumor biology and access to care are critical to answering this question. Our objectives were to explore how gastric cancer rates, receipt of care, and outcomes are affected by age, poverty, and acculturation. METHODS A total of 42,187 patients were identified from the 1980-2009 Surveillance, Epidemiology, and End Results registry. We compared trends in incidence rates between patients <40, 40-64, and ≥65 years using ordinary least-squares regression. Separate multivariate regression models were used to evaluate the impact of age, poverty, and acculturation on receipt of cancer-directed therapy and hazard of mortality. RESULTS Patients <40 years had stable incidence rates over the 3-decade period compared with decreases for patients 40-64 and ≥65 years. They are also more likely to present with aggressive, advanced disease (P < .0001 for both). On unadjusted and adjusted analyses, patients <40 years were more likely to receive cancer-directed therapies and have better survival than those ≥65 years. Residing in high poverty areas was associated with not receiving appropriate cancer-directed therapy; the adjusted hazard ratio of mortality for surgically resected patients was, however, not affected by poverty. Residing in high immigration areas was associated with a low hazard ratio (HR, 0.74; 95% confidence interval [CI], 0.7-0.79) of mortality. Foreign-born patients also had a low hazard ratio (HR, 0.87; 95% CI, 0.83-0.91) of mortality. CONCLUSION Although trends in incidence rates for patients <40 years remain unchanged and their disease is aggressive and advanced at presentation, they do not experience disparities in gastric cancer-directed therapies and survival after resection. For patients residing in impoverished areas or high immigration communities, operative resection and adjustment for appropriate aftercare is associated with comparable or better survival when compared with those living in low poverty or low immigration areas. Disparities remain in receipt of appropriate cancer-directed therapies, and future efforts should focus on decreasing structural variations in care and unconscious biases regarding patients from these vulnerable communities.
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Affiliation(s)
- David K Nguyen
- Department of Surgery, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA.
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14
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Abstract
Background The insula is a small but complex structure located in the depth of the sylvian fissure, covered by the frontal, parietal and temporal operculum. Ischemic strokes limited to the insula are rare and have not been well studied. Our objective is to better define the clinical presentation and outcome of insular ischemic strokes (IIS). Methods We reviewed the institutional prospective, consecutive stroke database from two centers to identify patients with IIS seen between 2008 and 2010. We also searched the Medline database using the keywords insula(r), infarction and stroke to identify previously published IIS cases confirmed by MRI. Minimal extension to an adjacent operculum or subinsular area was accepted. Clinicoradiological correlation was performed by distinguishing IIS involving the anterior (AIC) or posterior insular cortex (PIC). We collected clinical, demographic and radiological data. The outcome was determined using the modified Rankin Scale (mRS). Results We identified 7 patients from our institutions and 16 previously published cases of IIS. Infarcts were limited to the AIC (n = 4) or the PIC (n = 12) or affected both (n = 7). The five most frequent symptoms were somatosensory deficits (n = 10), aphasia (n = 10), dysarthria (n = 10), a vestibular-like syndrome (n = 8) and motor deficits (n = 6). A significant correlation was found between involvement of the PIC and somatosensory manifestations (p = 0.04). No other statistically significant associations were found. IIS presentation resembled a partial anterior circulation infarct (n = 9), a lacunar infarct (n = 2) or a posterior circulation infarct (n = 2). However, most cases presented findings that did not fit with these classical patterns (n = 10). At the 6 month follow up, mRS was 0 in 8/23 (35%) patients, 1–2 in 7/23 (30%) and unknown in 8/23 (35%). Conclusions IIS presentation is variable. Due to the confluence of functions in a restricted region, it results in multimodal deficits. It should be suspected when vestibular-like or motor but especially somatosensory, speech or language disturbances are combined in the same patient. The outcome of IIS is often favorable. Larger prospective studies are needed to better define the clinical presentation and outcome of IIS.
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Affiliation(s)
- F Lemieux
- Service de Neurologie, Hôpital Notre-Dame, Centre Hospitalier de l'Université de Montréal, Montréal, Qué., Canada
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15
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Safi-Harb M, Salam MT, Mirabbasi S, Nguyen DK, Sawan M. A low-power high-sensitivity CMOS mixed-signal seizure-onset detector. Annu Int Conf IEEE Eng Med Biol Soc 2012; 2011:5847-50. [PMID: 22255669 DOI: 10.1109/iembs.2011.6091446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this paper, we present a new seizure detection algorithm and the associated CMOS circuitry implementation. The proposed low-power seizure detector is a good candidate for an implantable epilepsy prosthesis. The device is designed for patient-specific seizure detection with a one variable parameter. The parameter value is extracted from a single seizure that is subsequently excluded from the validation phase. A two-path system is also proposed to minimize the detection delay. The algorithm is first validated using MATLAB® tools and then implemented and validated using circuits designed in a standard 0.18-μm CMOS process with a total power dissipation of 7.08 μW. A total of 13 seizures from two drug-resistant epileptic patients are assessed using the proposed algorithm and resulted in 100% sensitivity and a mean detection delay of 9.7 s after electrical onset.
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Affiliation(s)
- M Safi-Harb
- Polystim Neurotechnologies Laboratory, École Polytechnique de Montréal, Montréal, Canada
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16
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Moeller F, Tyvaert L, Nguyen DK, LeVan P, Bouthillier A, Kobayashi E, Tampieri D, Dubeau F, Gotman J. EEG-fMRI: adding to standard evaluations of patients with nonlesional frontal lobe epilepsy. Neurology 2009; 73:2023-30. [PMID: 19996077 DOI: 10.1212/wnl.0b013e3181c55d17] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE In patients with nonlesional frontal lobe epilepsy (FLE), the delineation of the epileptogenic zone is difficult. Therefore these patients are often not considered for surgery due to an unclear seizure focus. The aim of this study was to investigate whether EEG-fMRI can add useful information in the preoperative evaluation of these patients. METHODS Nine nonlesional FLE patients were studied with EEG-fMRI using a 3 T scanner. Spike-related blood oxygen level dependent (BOLD) signal changes were compared to the topography of the spikes and to PET and SPECT results if available. The structural MRIs were reviewed for subtle abnormalities in areas that showed BOLD responses. For operated patients, postoperative resection and histology were compared to BOLD responses. RESULTS Concordance between spike localization and positive BOLD response was found in 8 patients. PET and SPECT investigations corresponded with BOLD signal changes in 6 of 7 investigations. In 2 cases, reviewing the structural MRI guided by EEG-fMRI data resulted in considering a suspicious deep sulcus. Two patients were operated. In 1, the resected cortex corresponded with the suspicious sulcus and fMRI results and histology showed cortical dysplasia. In another, histology revealed an extended microdysgenesis not visible on structural MRI. EEG-fMRI had shown activation just adjacent to the resected pathologic area. CONCLUSIONS Our study provides different types of support (topography, concordance with PET and SPECT, structural peculiarities, postoperative histology) that EEG-fMRI may help to delineate the epileptic focus in patients with nonlesional frontal lobe epilepsy, a challenging group in the preoperative evaluation.
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Affiliation(s)
- F Moeller
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.
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17
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Tremblay C, Robert M, Pascual-Leone A, Lepore F, Nguyen DK, Carmant L, Bouthillier A, Théoret H. Action observation and execution: Intracranial recordings in a human subject. Neurology 2004; 63:937-8. [PMID: 15365160 DOI: 10.1212/01.wnl.0000137111.16767.c6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- C Tremblay
- Groupe de Recherche en Neuropsychologie et Cognition, Université de Montréal, Montréal, Québec, Canada
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18
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Affiliation(s)
- M-H Dion
- Division of Neurology, Department of Medicine, Centre Hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montreal, Quebec, Canada
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19
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Buford WL, Ivey FM, Nakamura T, Patterson RM, Nguyen DK. Internal/external rotation moment arms of muscles at the knee: moment arms for the normal knee and the ACL-deficient knee. Knee 2001; 8:293-303. [PMID: 11706692 DOI: 10.1016/s0968-0160(01)00106-5] [Citation(s) in RCA: 26] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Knowledge of the three-dimensional balance of loads at the knee joint is required to adequately assess the treatment and rehabilitation of the malfunctioning knee. This report focuses upon the moment arms for the knee in internal/external (IE) rotation motion. It augments prior work that defined flexion/extension moment arms. Muscle excursions and angular motion of the lower leg during IE rotation were measured in 17 fresh-frozen hemi-pelvis specimens. Moment arms were calculated as the derivatives of excursion with respect to the angle. Rotational motion was performed for the normal and anterior cruciate ligament (ACL)-deficient knee. Of the 13 muscles measured at the knee, seven were significant contributors to IE rotation: the biceps femoris long and short head externally rotate opposite the gracilis, sartorious, semimembranosis, semitendonosus and popliteus, functioning as internal rotators. Moment arm magnitudes were greatest with the knee in a flexed position (internal [external] rotators peaked at 70 degrees [90 degrees] flexion). At 30 degrees flexion, the IE rotation moment arm minima and maxima were 10.1-11.6, 6.8-9.0, 6.0-15.7, 8.2-14.1 and 0.0-10.4 mm for the semimembranosis, semitendonosus, gracilis, sartorius and popliteus, and 14.7-27.9 and 18.5-31.5 mm for the biceps femoris short and long, respectively. Moment arms for the ACL-deficient condition were significantly changed only at extremes of flexion-extension.
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Affiliation(s)
- W L Buford
- Orthopaedic Surgery and Rehabilitation, Biomechanics Laboratory, 301 University Boulevard, University of Texas Medical Branch, Galveston, TX 77555-0892, USA.
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20
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Pétra PH, Woodcock KT, Orr WR, Nguyen DK, Sui LM. The sex steroid binding protein (SBP or SHBG) of human plasma: identification of Tyr-57 and Met-107 in the steroid binding site. J Steroid Biochem Mol Biol 2000; 75:139-45. [PMID: 11226830 DOI: 10.1016/s0960-0760(00)00169-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Tyrosine-57 (Y57) and methionine-107 (M107) have been identified in the binding site of the sex steroid binding protein (SBP) (or sex hormone binding globulin) of human plasma by replacing the two amino acids with a number of residues of varying structure. Replacement of Y57 with phenylalanine resulted in a fourfold increase in the K(d) of 5 alpha-dihydrotestosterone but left the K(d) of 17 beta-estradiol unchanged. Except in two cases, no further loss in binding took place when replacing Y57 with other residues, suggesting that the phenolic group of Y57 may form a hydrogen bond with the ligand. Replacement of M107 with isoleucine increased the 5 alpha-dihydrotestosterone K(d) fourfold to a value equal to that of rabbit SBP, which contains isoleucine at the corresponding position; however, the K(d) of 17 beta-estradiol remained unchanged. Replacement of M107 with threonine resulted in a tenfold decrease in 5 alpha-dihydrotestosterone binding affinity, whereas replacement with leucine left the K(d) unchanged. These data indicate that substitutions on the beta-carbon of the amino acid side-chain at position 107 causes significant loss of binding affinity but, as in the case of Y57, the activity was not totally eliminated. We conclude that Y57 and M107 form part of a structural motif within the steroid binding site and specifically contribute binding energy to ring A of 5 alpha-dihydrotestosterone but not to ring A of 17 beta-estradiol. We also propose that the integrated contribution of several side chains may be required to optimize the ligand affinity of the steroid binding site. This proposal may fit a 'lock and key' model where little movement of the side chains occurs during binding as might be expected for a rigid structure like the steroid nucleus.
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Affiliation(s)
- P H Pétra
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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21
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Simon JA, Szankasi P, Nguyen DK, Ludlow C, Dunstan HM, Roberts CJ, Jensen EL, Hartwell LH, Friend SH. Differential toxicities of anticancer agents among DNA repair and checkpoint mutants of Saccharomyces cerevisiae. Cancer Res 2000; 60:328-33. [PMID: 10667584] [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: 02/15/2023]
Abstract
Most cytotoxic anticancer agents damage DNA directly, interfere with DNA metabolism or chromosome segregation, and are particularly toxic in dividing cells. Although a considerable amount of information on the mechanisms of action of these agents is available, the molecular bases for selective tumor cell killing by chemotherapy are largely unknown. Many genetic alterations found in sporadic and hereditary cancers affect functions in DNA repair and cell cycle control and result in sensitivity to DNA damaging agents. We have therefore set out to determine the effects of these cancer mutations on sensitivity or resistance to various chemotherapeutic agents. Because most of the affected genes are well conserved among eukaryotes, we have carried out a comprehensive analysis of a panel of isogenic yeast strains, each defective in a particular DNA repair or cell cycle checkpoint function, for sensitivity to the Food and Drug Administration-approved cytotoxic anticancer agents. Widely different toxicity profiles were observed for 23 agents and X-rays, indicating that the type of DNA repair and cell cycle checkpoint mutations in individual tumors could strongly influence the outcome of a particular chemotherapeutic regimen.
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Affiliation(s)
- J A Simon
- Molecular Pharmacology Program, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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22
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Hendrickson L, Davis CR, Roach C, Nguyen DK, Aldrich T, McAda PC, Reeves CD. Lovastatin biosynthesis in Aspergillus terreus: characterization of blocked mutants, enzyme activities and a multifunctional polyketide synthase gene. Chem Biol 1999; 6:429-39. [PMID: 10381407 DOI: 10.1016/s1074-5521(99)80061-1] [Citation(s) in RCA: 162] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Lovastatin, an HMG-CoA reductase inhibitor produced by the fungus Aspergillus terreus, is composed of two polyketide chains. One is a nonaketide that undergoes cyclization to a hexahydronaphthalene ring system and the other is a simple diketide, 2-methylbutyrate. Fungal polyketide synthase (PKS) systems are of great interest and their genetic manipulation should lead to novel compounds. RESULTS An A. terreus mutant (BX102) was isolated that could not synthesize the nonaketide portion of lovastatin and was missing a approximately 250 kDa polypeptide normally present under conditions of lovastatin production. Other mutants produced lovastatin intermediates without the methylbutyryl sidechain and were missing a polypeptide of approximately 220 kDa. The PKS inhibitor cerulenin reacted covalently with both polypeptides. Antiserum raised against the approximately 250 kDa polypeptide was used to isolate the corresponding gene, which complemented the BX102 mutation. The gene encodes a polypeptide of 269 kDa containing catalytic domains typical of vertebrate fatty acid and fungal PKSs, plus two additional domains not previously seen in PKSs: a centrally located methyltransferase domain and a peptide synthetase elongation domain at the carboxyl terminus. CONCLUSIONS The results show that the nonaketide and diketide portions of lovastatin are synthesized by separate large multifunctional PKSs. Elucidation of the primary structure of the PKS that forms the lovastatin nonaketide, as well as characterization of blocked mutants, provides new details of lovastatin biosynthesis.
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Affiliation(s)
- L Hendrickson
- ICOS Corporation, 22021 20th Ave SE, Bothell, WA 98021, USA
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23
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Abstract
During a 15-year period, 29 children, under the age of 6 years, with acute Guillain-Barré syndrome were seen at our institution. A review of their charts revealed that pain was a symptom in all patients and was present on admission in 79% of cases. Pain was often the most important symptom and led to misdiagnosis in 20 patients (69%). In 11 of these children, symptoms were present for more than a week before the correct diagnosis was made. The most common pain syndrome was back and lower limb pain, present in 83% of patients. Pediatricians should consider Guillain-Barré syndrome in their differential diagnosis when faced with a child who has lower limb pain and areflexia.
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Affiliation(s)
- D K Nguyen
- Division of Neurology, Department of Pediatrics, Hôpital Sainte-Justine and Université de Montréal, Montreal, Quebec, Canada
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24
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Abstract
We review forms of diaschisis and their relationship with neurobehavioral and neuropsychological findings. The following forms of diaschisis are discussed: (1) cortico-cerebellar diaschisis; (2) cerebello-cortical diaschisis; (3) transhemispheric diaschisis; (4) cortico-thalamic diaschisis; (5) thalamo-cortical diaschisis; and (6) basal ganglia-cortical diaschisis. For each form, the neurobehavioral and neuropsychological findings are discussed. Diaschisis can be classified from the behavioral point of view as follows: (1) forms in which the metabolic effect at distance is not followed by neurobehavioral impairment; (2) forms in which the remote metabolic impairment could induce neurobehavioral and neuropsychological disorders; and (3) forms in which the role of the lesion itself and its remote metabolic effects on the production of neurobehavioral and neuropsychological abnormalities cannot be disentangled.
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Affiliation(s)
- D K Nguyen
- Neurobiology and Neuropsychology Research Unit, Hôtel-Dieu Hospital, Montreal, Québec, Canada
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25
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Buford WL, Ivey FM, Malone JD, Patterson RM, Peare GL, Nguyen DK, Stewart AA. Muscle balance at the knee--moment arms for the normal knee and the ACL-minus knee. IEEE Trans Rehabil Eng 1997; 5:367-79. [PMID: 9422462 DOI: 10.1109/86.650292] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Forces, moments and stresses at the knee are dependent upon external and internal loading factors including muscle forces, segmental position and velocity, load carried, and the moment arms (mechanical advantage) of the muscle-tendon units. Requisite to prediction of forces and moments is a detailed understanding of effective moment arms throughout the knee range-of-motion (ROM). Existing muscle models for the knee are based upon limited static studies of only a few preserved specimens. The objectives of this report are to develop a comprehensive description of muscle-tendon moment arms for the normal knee and the anterior cruciate ligament (ACL)-minus knee during flexion-extension motion. Recent research results describe two nonorthogonal, nonintersecting axes of motion for the knee--one describing flexion-extension (FE) and the other longitudinal rotation (LR, equivalent to internal-external rotation). The effective flexion-extension moment arms of the muscles crossing the knee were developed with respect to the FE axis in 15 fresh, hemi-pelvis cadaver specimens. The normal moment arms for each of 13 muscles plus the patellar tendon exhibited variable, yet repeatable and recognizable patterns throughout the ROM. For most muscles there was no significant difference between the normal and ACL-minus moment arms. The results provide a basis for more accurate predictions of joint reaction forces and moments as well as useful knowledge for practitioners and therapists to assist in the assessment of muscle balance at the knee following injury, repair, and throughout rehabilitation.
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Affiliation(s)
- W L Buford
- Biomechanics Laboratory, Orthopaedic Surgery and Rehabilitation, University of Texas Medical Branch, Galveston 77555, USA
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26
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Woo DD, Nguyen DK, Khatibi N, Olsen P. Genetic identification of two major modifier loci of polycystic kidney disease progression in pcy mice. J Clin Invest 1997; 100:1934-40. [PMID: 9329956 PMCID: PMC508382 DOI: 10.1172/jci119724] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [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] [Indexed: 02/05/2023] Open
Abstract
Unlike the uniform disease progression in inbred animals, polycystic kidney disease (PKD) progression within human families can be highly variable. This may be due to environmental or genetic factors or both. To determine if PKD severity can be influenced by modifier genes, we carried out an intercross between DBA/2-pcy/pcy and Mus m. castaneous involving 3,105 6-wk-old F2 mice. Large differences in PKD severity were observed in this cross. In addition, 23/ 800 phenotypically normal mice were pcy/pcy genotypically. These results demonstrated that PKD progression in pcy/ pcy mice is a quantitative trait that is strongly modulated by modifier genes. Whole genome quantitative trait loci mapping of 114 selected pcy/pcy mice (68 with the mild PKD and 46 with severe PKD) identified two loci, MOP1 and MOP2 that strongly modulate PKD progression. MOP1 (max LOD score = 10.3 at D4Mit111) and MOP2 (max LOD score = 13.8 at D16Mit1) accounted for 36.7 and 46.8% of the phenotypic variance, respectively. Two-factor ANOVA of the phenotypes and genotypes of all 673 pcy/pcy mice from our cross indicated that MOP1 and MOP2 alleles regulate PKD progression in a complex additive manner. Characterization of these novel modifying loci may provide additional insights into the pathogenesis of polycystic kidney diseases.
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Affiliation(s)
- D D Woo
- Department of Medicine, UCLA School of Medicine, Los Angeles, California 90095-1689, USA.
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27
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Nguyen DK, Bruchet A, Arpino P. Determination of Sterols in Sewage Sludge by Combined in Situ Trimethylsilylation/Supercritical Fluid Extraction and GC/MS. Environ Sci Technol 1995; 29:1686-1690. [PMID: 22276896 DOI: 10.1021/es00006a037] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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St-Denis JF, Comte B, Nguyen DK, Seidman E, Paradis K, Lévy E, van de Werve G. A conformational model for the human liver microsomal glucose-6-phosphatase system: evidence from rapid kinetics and defects in glycogen storage disease type 1. J Clin Endocrinol Metab 1994; 79:955-9. [PMID: 7962304 DOI: 10.1210/jcem.79.4.7962304] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 01/28/2023]
Abstract
Rapid kinetics of glucose-6-phosphate (G6P) uptake and hydrolysis as well as of orthophosphate uptake were investigated in microsomes prepared from normal and glycogen storage disease type 1a (GSD 1a) human livers using a fast sampling, rapid filtration apparatus and were compared to those of rat liver microsomes. As shown before with rat microsomes, the production of [U-14C]glucose from 0.2 mmol/L [U-14C]G6P by untreated normal human microsomes was characterized by a burst in activity during the first seconds of incubation, followed by a slower linear rate. The initial velocity of the burst was equal to the rate of glucose production in detergent-treated microsomes. In untreated and detergent-treated GSD 1a microsomes, no glucose-6-phosphatase activity was observed. When untreated normal human or rat microsomes were incubated in the presence of 0.2 mmol/L [U-14C]G6P, an accumulation of [U-14C]glucose was observed, whereas no radioactive compound (G6P and/or glucose) was taken up by GSD 1a microsomes. Orthophosphate uptake was, however, detectable in both GSD 1a and normal untreated vesicles. These results do not support a rate-limiting transport of G6P in untreated normal human microsomes and further show that in this case of GSD 1a, no distinct G6P transport activity is present.
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Affiliation(s)
- J F St-Denis
- Department of Nutrition, Hôpital Sainte-Justine, Quebec, Canada
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Abstract
The postulate that the hemodynamic changes produced by isoflurane (1.5%) involve release of nitric oxide (NO) was examined. Fifteen dogs were anesthetized with thiamylal (15 mg/kg) and ventilated with isoflurane and oxygen. Catheters were inserted for measurement of aortic pressure, pulmonary artery pressures, and determination of cardiac output. Left thoracotomy was performed and complete heart block was induced by injection of 37% formaldehyde (0.3 mL) into the atrioventricular node; ventricular rate was fixed at 100 beats/min by external pacing. An apical microtransducer was inserted into the left ventricle (LV) via the apex for measurement of left ventricular pressure (LVP) and its first derivative (dP/dt). Flow probes were mounted on the left circumflex (Cx) and anterior descending (AD) coronary arteries. Measurements were obtained before (control period) and during NO inhibition using IV NG-nitro-L-arginine methyl ester (L-NAME) by a 50 mg/kg bolus plus 1 mg/kg/min. Infusion of L-NAME caused immediate and sustained increases in mean arterial pressure to 145 +/- 3% (P < 0.001), mean pulmonary arterial pressure to 128 +/- 5% (P < 0.001), pulmonary capillary wedge pressure to 144 +/- 8% (P < 0.001), coronary perfusion pressure to 163 +/- 4% (P < 0.001), systemic vascular resistance to 209 +/- 9% (P < 0.001), pulmonary vascular resistance to 142 +/- 12% (P < 0.005), anterior descending flow to 115 +/- 4% (P < 0.005), and circumflex flow to 113 +/- 3% (P < 0.01) of control levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P G Moore
- Department of Anesthesiology, University of California-TB 170, Davis 95616
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30
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Abstract
In this study, it was demonstrated that site-specific suppression of T-cell-mediated immune responsiveness could indeed be achieved by topical application of cyclosporine. Evidence for site-specific immune suppression was obtained from a dual skin allograft model in rats. These animals were given an initial 10-d systemic treatment of CsA. Subsequently, one allograft was treated with topical CsA and the other was treated with the vehicle alone. Anti-inflammatory efficacy and prolonged skin allograft survival were observed both grossly and histopathologically in the presence of topically administered CsA, while contralateral vehicle-treated control grafts underwent vigorous rejection. Systemic lymphocyte DNA synthesis following Con-A and PHA stimulation was normal to elevated. Therefore, systemic T-cell-mediated immunity appeared unaffected or possibly activated even with concomitant topical CsA treatment. CsA levels were low systemically, and showed relative site-specificity in terms of tissue concentration. In conclusion, this study indicates that topical CsA is capable of locally suppressing a strong T-cell-mediated immune response after an initial short-term systemic dose of CsA. Furthermore, certain putative autoimmune and inflammatory diseases of the skin, such as psoriasis and eczematous dermatitis, which may share common mechanisms of action compared to skin allograft rejection should likewise benefit from topical CsA treatment.
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Affiliation(s)
- K S Black
- Transplantation Laboratory, University of California, Irvine 92717
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