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Nguyen NH, VuTien P, Garcia RT, Trinh H, Nguyen H, Nguyen K, Levitt B, Nguyen MH. Response to pegylated interferon and ribavirin in Asian American patients with chronic hepatitis C genotypes 1 vs 2/3 vs 6. J Viral Hepat 2010; 17:691-7. [PMID: 20002562 DOI: 10.1111/j.1365-2893.2009.01226.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Chronic hepatitis C is generally underappreciated in Asian Americans, and most pivotal studies were conducted in western countries and only included a small numbers of Asian patients. Our goal was to examine and compare treatment outcomes in these patients with genotypes 1 vs 2/3 vs 6. We performed a retrospective cohort study of 167 consecutive treatment-naïve Asian American patients treated with pegylated interferon (PEG IFN) plus ribavirin (RBV) at two community clinics in Northern California from 12/00 to 1/08. Primary outcome was sustained virological response rate by intention-to-treat analysis. The overall completion rate was 76%, and treatment adherence (completion of ≥ 75-80% PEG IFN + RBV dose for ≥ 75-80% of intended duration) was 74%. Significant depression was noted in only 4% of patients. Sustained virologic response in patients with genotype 6 treated for 48 weeks was similar to that seen in those with genotype 2/3 (74%vs 75%, P = 0.89) and significantly higher than those with genotype 1 (74%vs 49%, P = 0.016). On multivariate analysis inclusive of sex, age, body mass index (≤ 25 vs > 25) and viral load, only treatment adherence and genotype (2/3 and 6 treated for 48 weeks) were found to be significant predictors of sustained virologic response. We conclude that significant depression is rare in Asian American patients (4%). Patients with genotype 6 treated for 48 weeks appear to have a similar treatment response rate as patients with genotype 2/3 and a significantly higher response rate than those with genotype 1.
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Nguyen MH, Garcia RT, Trinh HN, Nguyen HA, Nguyen KK, Nguyen LH, Levitt B. Prevalence of hepatitis B virus DNA polymerase mutations in treatment-naïve patients with chronic hepatitis B. Aliment Pharmacol Ther 2009; 30:1150-8. [PMID: 19785624 DOI: 10.1111/j.1365-2036.2009.04151.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND One of the most important factors in treatment failure using nucleos(t)ide analogues in chronic hepatitis B is anti-viral resistance. Primary drug resistance refers to amino acid changes in the hepatitis B virus polymerase/reverse transcriptase (rt) that result in reduced susceptibility to anti-viral agents. Pre-existing drug resistance mutations may occur in untreated patients and may affect their treatment outcomes. AIM To determine the prevalence of hepatitis B DNA polymerase mutations in treatment-naïve patients. METHODS We used a direct PCR sequencing test to detect DNA polymerase mutations in 472 consecutive treatment-naïve patients at two community gastroenterology clinics in Northern California. RESULTS A majority of patients were Asians (>95%), had either genotype B or C (95%) and had no evidence of cirrhosis or liver cancer (94%). Mean age was 45 +/- 13 and mean hepatitis B virus DNA was 5.3 +/- 1.8 log(10) IU/mL. Most patients did not have any detectable mutations (82.4%). Some (16.7%) had mutations of unknown clinical significance (rtV207M/L/I) and only 4 patients had rtA181A/S, rtA194S or M250I. CONCLUSIONS No rtM204V/I or rtN236T mutations were observed in our study. Less than 1% of our patients had mutations that can be associated with primary resistance to existing anti-viral therapies for hepatitis B virus.
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De Luna W, Sze DY, Ahmed A, Ha BY, Ayoub W, Keeffe EB, Cooper A, Esquivel C, Nguyen MH. Transarterial chemoinfusion for hepatocellular carcinoma as downstaging therapy and a bridge toward liver transplantation. Am J Transplant 2009; 9:1158-68. [PMID: 19344435 DOI: 10.1111/j.1600-6143.2009.02576.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Favorable outcomes after liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) are well described for patients who fall within defined tumor criteria. The effectiveness of tumor therapies to maintain tumor characteristics within these criteria or to downstage more advanced tumors to fall within these criteria is not well understood. The aim of this study was to examine the response to transcatheter arterial chemoinfusion (TACI) in HCC patients awaiting LT and its efficacy for downstaging or bridging to transplantation. We performed a retrospective study of 248 consecutive TACI cases in 122 HCC patients at a single U.S. medical center. Patients were divided into two groups: those who met the Milan criteria on initial HCC diagnosis (n = 95) and those with more advanced disease (n = 27). With TACI treatment, 87% of the Milan criteria group remained within the Milan criteria and 63% of patients with more advanced disease were successfully downstaged to fall within the Milan criteria. In conclusion, TACI appears to be an effective treatment as a bridge to LT for nearly 90% patients presenting within the Milan criteria and an effective downstaging modality for over half of those whose tumor burden was initially beyond the Milan criteria.
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Perrin F, Nguyen MH, Vernet J. Water transport in epoxy–aliphatic amine networks – Influence of curing cycles. Eur Polym J 2009. [DOI: 10.1016/j.eurpolymj.2009.01.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Nguyen G, Garcia RT, Nguyen N, Trinh H, Keeffe EB, Nguyen MH. Clinical course of hepatitis B virus infection during pregnancy. Aliment Pharmacol Ther 2009; 29:755-64. [PMID: 19183158 DOI: 10.1111/j.1365-2036.2009.03932.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND For women with hepatitis B virus (HBV) infection, little is known about the natural progression of the disease during pregnancy or its impact on pregnancy outcomes. OBJECTIVES To investigate the natural progression of HBV infection during pregnancy or its impact on pregnancy outcomes. METHODS In this retrospective cohort study, we reviewed medical records of all patients who were pregnant and presented with HBsAg-positivity between 2000 and 2008 at a community gastroenterology practice and a university hepatology clinic. Maternal characteristics were analysed according to maternal and perinatal outcomes. RESULTS A total of 29 cases with at least 2 measurements of either HBV DNA or alanine aminotransferase (ALT) levels were included. Older age was the only predictor of a trend towards higher risk of an adverse clinical outcome [OR = 1.21 (0.97-1.51), P = 0.089], defined as either a negative foetal outcome (premature delivery, spontaneous abortion), or a negative maternal outcomes (gestational diabetes mellitus, pre-eclampsia, hepatic flare, liver failure). This trend for age remained even after adjusting for baseline ALT. Baseline serum HBV DNA, ALT, hepatitis B e antigen status, gravida and parity were not significant predictors for adverse clinical outcomes. Four patients developed liver failure. CONCLUSIONS Maternal and neonatal outcomes are highly variable in this clinic-based patient cohort. Severe complications due to HBV infection can occur during pregnancy in previously asymptomatic patients. It is unclear how generalizable the results observed in this cohort would be to the general population; therefore, further studies are needed to identify reliable predictors for significant adverse outcomes and until more data are available, pregnant patients with HBV infection should be monitored with periodic serum HBV DNA and ALT levels.
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Nguyen MH, Keeffe EB. Chronic hepatitis B: early viral suppression and long-term outcomes of therapy with oral nucleos(t)ides. J Viral Hepat 2009; 16:149-55. [PMID: 19236641 DOI: 10.1111/j.1365-2893.2009.01078.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chronic hepatitis B is a serious health problem worldwide with a substantial minority of patients experiencing premature death due to end-stage liver disease and/or hepatocellular carcinoma. Antiviral therapy may help prevent complications of chronic hepatitis B, and seven agents are currently approved in many countries. Of these agents, five are nucleos(t)ide analogs that all have a risk of antiviral drug resistance with long-term use. Efforts have been made in the recent years to prevent or to reduce the risk of viral resistance in patients treated with oral nucleos(t)ides as the majority of these patients will require therapy for 3-5 years or longer. One approach is to identify patients who would most likely develop antiviral resistance on long-term therapy using predictors obtainable early in the course of treatment, when intervention with new or additional therapy can be instituted. The most important predictors of treatment outcomes are serum HBV DNA levels at baseline and during the first 6 months of therapy. The purpose of this synopsis is to review the recent literature regarding the importance of serum HBV DNA levels in association with treatment outcomes in chronic hepatitis B, particularly the association of complete viral suppression early in the course of oral therapy with long-term treatment outcomes, particularly the incidence of antiviral drug resistance.
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Ha BY, Ahmed A, Sze DY, Razavi MK, Simpson N, Keeffe EB, Nguyen MH. Long-term survival of patients with unresectable hepatocellular carcinoma treated with transcatheter arterial chemoinfusion. Aliment Pharmacol Ther 2007; 26:839-46. [PMID: 17767468 DOI: 10.1111/j.1365-2036.2007.03424.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND Transcatheter arterial chemoembolization (TACE) has become one of the most common treatments for unresectable hepatocellular carcinoma. Published studies of TACE report a 5-16% risk of serious complications. Compared with TACE, transcatheter arterial chemoinfusion (TACI) may have similar efficacy and fewer side effects. AIM To examine the clinical outcomes of TACI. METHODS We performed a retrospective cohort study of 345 consecutive TACI cases in 165 patients performed at a single United States medical center between 1998 and 2002. Primary outcomes were tumour response and survival rates. RESULTS Only seven patients were hospitalized for more than 24 h after the procedure, and only three patients had worsening of liver function within 30 days of TACI. Survival was significantly poorer for patients with tumour-node-metastasis (TNM) IV compared to those with TNM I-III and also for patients with Child's class B/C vs. A. Following adjustment for age, gender, ethnicity and aetiology of liver diseases, independent predictors of poor survival were Child's class B/C [Hazard Ratio (HR) = 1.69, P = 0.024] and TNM IV staging (HR = 1.63, P = 0.014). CONCLUSIONS TACI appears to be safe and effective for unresectable hepatocellular carcinoma with TNM stage I-III; randomized controlled trials are needed to compare TACI to TACE.
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Nguyen MH, Annest JL, Mercy JA, Ryan GW, Fingerhut LA. Trends in BB/pellet gun injuries in children and teenagers in the United States, 1985-99. Inj Prev 2002; 8:185-91. [PMID: 12226113 PMCID: PMC1730879 DOI: 10.1136/ip.8.3.185] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To characterize national trends in non-fatal BB/pellet gun related injury rates for persons aged 19 years or younger in relation to trends in non-fatal and fatal firearm related injury rates and discuss these trends in light of injury prevention and violence prevention efforts. SETTING The National Electronic Injury Surveillance System (NEISS) includes approximately 100 hospitals with at least six beds that provide emergency services. These hospitals comprise a stratified probability sample of all US hospitals with emergency departments. The National Vital Statistics System (NVSS) is a complete census of all death certificates filed by states and is compiled annually. METHODS National data on BB/pellet gun related injuries and injury rates were examined along with fatal and non-fatal firearm related injuries and injury rates. Non-fatal injury data for all BB/pellet gun related injury cases from 1985 through 1999, and firearm related injury cases from 1993 through 1999 were obtained from hospital emergency department records using the NEISS. Firearm related deaths from 1985 through 1999 were obtained from the NVSS. RESULTS BB/pellet gun related injury rates increased from age 3 years to a peak at age 13 years and declined thereafter. In contrast, firearm related injury and death rates increased gradually until age 13 and then increased sharply until age 18 years. For persons aged 19 years and younger, BB/pellet gun related injury rates increased from the late 1980s until the early 1990s and then declined until 1999; these injury rates per 100 000 population were 24.0 in 1988, 32.8 in 1992, and 18.3 in 1999. This trend was similar to those for fatal and non-fatal firearm related injury rates per 100 000 which were 4.5 in 1985, 7.8 in 1993, and 4.3 in 1999 (fatal) and 38.6 in 1993 and 16.3 in 1999 (non-fatal). In 1999, an estimated 14 313 (95% confidence interval (CI) 12 025 to 16 601) cases with non-fatal BB/pellet gun injuries and an estimated 12 748 (95% CI 7881-17 615) cases with non-fatal firearm related injuries among persons aged 19 years and younger were treated in US hospital emergency departments. CONCLUSIONS BB/pellet gun related and firearm related injury rates show similar declines since the early 1990s. These declines coincide with a growing number of prevention efforts aimed at reducing injuries to children from unsupervised access to guns and from youth violence. Evaluations at the state and local level are needed to determine true associations.
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Beaumont C, Jamieson RA, Nguyen MH, Lee B. Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation. Nature 2001; 414:738-42. [PMID: 11742396 DOI: 10.1038/414738a] [Citation(s) in RCA: 1189] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent interpretations of Himalayan-Tibetan tectonics have proposed that channel flow in the middle to lower crust can explain outward growth of the Tibetan plateau, and that ductile extrusion of high-grade metamorphic rocks between coeval normal- and thrust-sense shear zones can explain exhumation of the Greater Himalayan sequence. Here we use coupled thermal-mechanical numerical models to show that these two processes-channel flow and ductile extrusion-may be dynamically linked through the effects of surface denudation focused at the edge of a plateau that is underlain by low-viscosity material. Our models provide an internally self-consistent explanation for many observed features of the Himalayan-Tibetan system.
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Abstract
Until recently, interferon monotherapy has been the only available therapeutic option for patients with chronic hepatitis B and hepatitis C. Lamivudine has emerged as another effective first-line therapy for chronic hepatitis B as well as a beneficial treatment option for patients with decompensated hepatitis B cirrhosis. Viral resistance with long-term lamivudine therapy remains a major concern but new data continue to show benefits despite the development of YMDD mutations. Combination therapy with ribavirin and pegylated interferon-alpha has revolutionized the treatment of chronic hepatitis C. The rate of sustained virological response can now be expected to be as high as nearly 50% for genotype 1 and 80% for non-1 genotypes of hepatitis C.
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Samsa GP, Kolotkin RL, Williams GR, Nguyen MH, Mendel CM. Effect of moderate weight loss on health-related quality of life: an analysis of combined data from 4 randomized trials of sibutramine vs placebo. THE AMERICAN JOURNAL OF MANAGED CARE 2001; 7:875-83. [PMID: 11570021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
OBJECTIVES To determine whether (1) patients who experience greater weight loss also experience correspondingly greater improvements in health-related quality of life (HRQOL); (2) the improvement in HRQOL is noticeable for patients achieving moderate (5%-10%) weight reduction; and (3) the relationship between weight reduction and HRQOL is similar for patients receiving sibutramine hydrochloride vs placebo. STUDY DESIGN We combined data from 4 double-blind, randomized, controlled trials of administration of sibutramine (20 mg/d) vs placebo. PATIENTS AND METHODS Patients (n = 555) were mildly to moderately obese and had type 2 diabetes mellitus, dyslipidemia, or hypertension that was well controlled with an angiotensin-converting enzyme inhibitor or calcium channel blocker. The HRQOL was operationalized using the Impact of Weight on Quality of Life (IWQOL) and the Medical Outcomes Study 36-Question Short-Form (SF-36) instruments. The main statistical technique was a patient-level analysis of variance predicting change in HRQOL from study, treatment, and weight change. RESULTS Moderate weight loss was associated with a statistically significant improvement in HRQOL for approximately half of the subscales evaluated (P < .05). The greatest sensitivity to change was shown by the SF-36 general health perception and change in health since last year subscales and the IWQOL overall health, mobility, and total subscales. Greater weight loss was associated with the most improvement in HRQOL. Weight losses of 5.01% to 10.00% were associated with 2-unit changes in the SF-36 general health perception subscale and 10-unit changes in the IWQOL total subscale. Results were similar across study and treatment. CONCLUSIONS Moderate weight loss is associated with noticeably improved HRQOL. Improvements in HRQOL are achievable by patients receiving sibutramine.
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Nguyen MH, Ho JM, Beattie BK, Barber DL. TEL-JAK2 mediates constitutive activation of the phosphatidylinositol 3'-kinase/protein kinase B signaling pathway. J Biol Chem 2001; 276:32704-13. [PMID: 11435425 DOI: 10.1074/jbc.m103100200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A subset of chromosomal translocations that participate in leukemia involve activated tyrosine kinases. The ets transcription factor, TEL, undergoes translocations with several distinct tyrosine kinases including JAK2. TEL-JAK2 transforms cell lines to factor independence, and constitutive tyrosine kinase activity results in the phosphorylation of several substrates including STAT1, STAT3, and STAT5. In this study we have shown that TEL-JAK2 can constitutively activate the phosphatidylinositol 3'-kinase (PI 3'-kinase) signaling pathway. The regulatory subunit of PI 3'-kinase, p85, associates with TEL-JAK2 in immunoprecipitations, and this was shown to be mediated by the amino-terminal SH2 domain of p85 but independent of a putative p85-binding motif within TEL-JAK2. The scaffolding protein Gab2 can also mediate the association of p85. TEL-JAK2 constitutively phosphorylates the downstream substrate protein kinase B/AKT. Importantly, the pharmacologic PI 3'-kinase inhibitor, LY294002, blocked TEL-JAK2 factor-independent growth and phosphorylation of protein kinase B. However, LY294002 did not alter STAT5 tyrosine phosphorylation, indicating that STAT5 and protein kinase B activation mediated by TEL-JAK2 are independent signaling pathways. Therefore, activation of the PI 3'-kinase signaling pathway is an important event mediated by TEL-JAK2 chromosomal translocations.
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Barber DL, Beattie BK, Mason JM, Nguyen MH, Yoakim M, Neel BG, D'Andrea AD, Frank DA. A common epitope is shared by activated signal transducer and activator of transcription-5 (STAT5) and the phosphorylated erythropoietin receptor: implications for the docking model of STAT activation. Blood 2001; 97:2230-7. [PMID: 11290583 DOI: 10.1182/blood.v97.8.2230] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Erythropoietin (EPO) specifically activates the Janus kinase JAK2 and the transcription factor signal transducer and activator of transcription-5 (STAT5). All members of the STAT family are tyrosine phosphorylated in response to cytokine stimulation at a conserved carboxy-terminal tyrosine, Y694, in the case of STAT5. To determine structural features important for STAT signaling, we generated an activation-specific STAT5 antibody using a phosphopeptide containing amino acids 687 to 698 of STAT5 as antigen. This antibody specifically recognizes tyrosine- phosphorylated STAT5 but not nonphosphorylated STAT5. In immunoprecipitation reactions from cell lines and primary erythroblasts, 2 distinct polyclonal activation-specific STAT5 antibodies selectively immunoprecipitate the tyrosine phosphorylated EPO receptor (EPO-R) in addition to STAT5 under native and denaturing conditions. We propose that the activation-specific STAT5 antibody recognizes the 2 substrates to which the STAT5 SH2 domain interacts, namely, the tyrosine- phosphorylated EPO-R and STAT5 itself. Several studies have implicated EPO-R Y343, Y401, Y431, and Y479 in the recruitment of STAT5. Using a series of EPO-R tyrosine mutants expressed in Ba/F3 cells, we have shown that the activation-specific STAT5 antibody immunoprecipitates an EPO-R containing only 2 tyrosines at positions 343 and 401, confirming the importance of these tyrosines in STAT5 recruitment. These data uncover a novel aspect of STAT SH2 domain recognition and demonstrate the utility of activation-specific antibodies for examining the specificity of STAT-cytokine receptor interactions.
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Zhang MY, Barber DL, Alessi DR, Bell LL, Stine C, Nguyen MH, Beattie BK, Cheung JY, Miller BA. A minimal cytoplasmic subdomain of the erythropoietin receptor mediates p70 S6 kinase phosphorylation. Exp Hematol 2001; 29:432-40. [PMID: 11301183 DOI: 10.1016/s0301-472x(00)00681-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Erythropoietin (EPO) is a lineage-restricted growth factor that is required for erythroid proliferation and differentiation. EPO stimulates the phosphorylation and activation of p70 S6 kinase (p70 S6K), which is required for cell cycle progression. Here, the minimal cytoplasmic domains of the EPO receptor (EPO-R) required for p70 S6K activation were determined.Ba/F3 cells were stably transfected with wild-type (WT) EPO-R or EPO-R carboxyl-terminal deletion mutants, designated by the number of amino acids deleted from the cytoplasmic tail (-99, -131, -221). Transfected cells were growth factor deprived and then stimulated with EPO. p70 S6K, JAK2, IRS-2, and ERK1/2 phosphorylation/activation were examined. The ability of transfected 3-phosphoinositide-dependent protein kinase 1 (PDK1) to reconstitute p70 S6K phosphorylation in EPO-R mutants also was determined. Phosphorylation and activation of p70 S6K, JAK2, IRS-2, and ERK1/2 in Ba/F3 cells transfected with EPO-R-99 or EPO-R-99Y343F were similar to WT EPO-R. In contrast, EPO-dependent p70 S6K phosphorylation/activation, as well as IRS-2 and ERK1/2 phosphorylation, were minimal or absent in cells transfected with EPO-R-131 or EPO-R-221. JAK2 phosphorylation was reduced significantly in cells transfected with EPO-R-131 and abolished with EPO-R-221. To examine the role of PDK1, a kinase known to phosphorylate p70 S6K, Ba/F3 EPO-R-131 cells were transiently transfected with PDK1. WT constitutively active PDK1 restored p70 S6K phosphorylation in Ba/F3 EPO-R-131 cells but not in Ba/F3 EPO-R-221 cells. The results demonstrate that a minimal cytoplasmic subdomain of the EPO-R extending between -99 and -131 is required for p70 S6K phosphorylation and activation. The results also demonstrate that PDK1 is a critical component in this signaling pathway, which requires the presence of domains between -131 and -221 for its activation of p70 S6K.
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Clancy CJ, Barchiesi F, Falconi DiFrancesco L, Morris AJ, Snydman DR, Yu VL, Scalise G, Nguyen MH. Clinical manifestations and molecular epidemiology of late recurrent candidemia, and implications for management. Eur J Clin Microbiol Infect Dis 2000; 19:585-92. [PMID: 11014620 DOI: 10.1007/s100960000335] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of this study was to define the epidemiology and clinical manifestations of late recurrent candidemia. For this purpose, late recurrent candidemia was defined as an episode of candidemia occurring at least 1 month after the apparent complete resolution of an infectious episode caused by the same Candida sp. A total of five patients with recurrent candidemia were investigated. For all patients, isolates from the initial and recurrent episodes of candidemia were available for in vitro susceptibility testing and genetic characterization by DNA-based techniques. The results revealed the following salient features: prolonged duration between the initial and recurrent episodes (range, 1-8 months); recurrence of candidemia despite anti-fungal therapy; importance of retained intravascular catheters, neutropenia, and corticosteroids as factors predisposing to recurrence; high morbidity and mortality; no emergence of antifungal drug resistance between the initial and recurrent episodes; and relapse of infection due to the original infecting strain, rather than reinfection with a new strain. These findings raise several issues about the management and follow-up of patients with candidemia, which require assessment in future studies.
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Nguyen MH, Tokura H. The different effects of black and white Vietnamese Aodai folk costumes on rectal temperature and heart rate in women walking intermittently in hot and sunny environment. Int J Occup Med Environ Health 2000; 13:27-38. [PMID: 10846843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
The present study was undertaken to investigate whether there is any difference in the rectal temperature and heart rate between women wearing black or white Aodai folk costume and walking intermittently in natural sunlight. The experiment was performed in the field outside buildings in Hanoi, Vietnam, between May and June, 1998. The only difference was in the colour (black or white) of clothing other physical characteristics, like materials, thickness, weight and so on, were nearly identical. Air temperature was around 39 degrees C, globe temperature around 52 degrees C and sun radiation reached 1010 W.m-2. Eight young female students (aged 20 years) participated in the experiment. They sat quietly on a chair inside the building for the first 30 min. Then they walked for 20 min at their ordinary walking speed in the sun, and rested for 10 min in the shade. This schedule was repeated three times. The main results are summarised as follows: (1) Rectal temperature was significantly lower in the black than in the white Aodai; (2) Clothing microclimate temperature at frontal chest level was also significantly lower in the black Aodai; (3) Heart rate was significantly lower in the black than in the white Aodai; (4) Clothing surface and inside temperatures measured at frontal chest level were significantly higher in the black than in the white Aodai. These results strongly suggest that the black Aodai could reduce heat strain more effectively than the white one. The physiological mechanism may result from more effective ventilation between skin and clothing in the black Aodai, due to higher temperature inside and outside this garment.
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Nguyen MH, Yu VL, Morris AJ, McDermott L, Wagener MW, Harrell L, Snydman DR. Antimicrobial resistance and clinical outcome of Bacteroides bacteremia: findings of a multicenter prospective observational trial. Clin Infect Dis 2000; 30:870-6. [PMID: 10852736 DOI: 10.1086/313805] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/1999] [Revised: 11/17/1999] [Indexed: 11/03/2022] Open
Abstract
There is debate regarding the correlation between in vitro susceptibility testing and clinical response to therapy for Bacteroides bacteremia. We conducted a prospective multicenter observational study of 128 patients with bacteroides bacteremia. Outcome was correlated with results of in vitro susceptibility testing of Bacteroides isolates recovered from blood and/or nonblood sites, determined with use of 3 end points: mortality at 30 days, clinical response (cure vs. failure), and microbiological response (eradication vs. persistence). The mortality rate among patients who received inactive therapy (45%) was higher than among patients who received active therapy (16%; P=.04). Clinical failure (82%) and microbiological persistence (42%) were higher for patients who received inactive therapy than for patients who received active therapy (22% and 12%, respectively; P=.0002 and.06, respectively). In vitro activity of agents directed at Bacteroides species reliably predicts outcome: the specificity was 97%, and positive predictive value was 82%. Antimicrobial susceptibility testing may be indicated for patients whose blood specimens yield Bacteroides species.
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Nguyen MH, Pittas F. How large should a skin trephine be for an end stoma? THE AUSTRALIAN AND NEW ZEALAND JOURNAL OF SURGERY 1999; 69:675-6. [PMID: 10515344 DOI: 10.1046/j.1440-1622.1999.01663.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Although much has been written about techniques for making a good stoma, little has been described regarding how to excise a trephine that will perfectly fit a given end stoma. METHODS A reproducible technique for making a stomal trephine to a precise fit for each stoma is described. RESULTS More than 20 stomas have been made with good results. CONCLUSION The skin trephine should have a diameter approximately two-thirds of the width of the crushed bowel end.
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Clancy CJ, Nguyen MH. Correlation between in vitro susceptibility determined by E test and response to therapy with amphotericin B: results from a multicenter prospective study of candidemia. Antimicrob Agents Chemother 1999; 43:1289-90. [PMID: 10223955 PMCID: PMC89262 DOI: 10.1128/aac.43.5.1289] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ninety-nine Candida bloodstream isolates underwent testing for susceptibility to amphotericin B by the E test, and the results were correlated with patients' responses to amphotericin B. The MICs for isolates that were associated with therapeutic failure were significantly higher than the MICs for those associated with therapeutic success. A MIC of >/=0.38 microgram/ml identified isolates likely to be associated with therapeutic failure.
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Nguyen MH, Kauffman CA, Goodman RP, Squier C, Arbeit RD, Singh N, Wagener MM, Yu VL. Nasal carriage of and infection with Staphylococcus aureus in HIV-infected patients. Ann Intern Med 1999; 130:221-5. [PMID: 10049200 DOI: 10.7326/0003-4819-130-3-199902020-00026] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Staphylococcus aureus is a common cause of serious infection in patients infected with HIV. OBJECTIVES To evaluate risk factors for and quantitative effect of S. aureus infection in HIV-infected patients, with special attention to nasal carriage. DESIGN Prospective, multihospital cohort study. SETTING Three tertiary care Veterans Affairs Medical Centers. PARTICIPANTS 231 ambulatory HIV-infected patients. RESULTS Thirty-four percent of patients were nasal carriers of S. aureus. Of these patients, 38% were persistent carriers and 62% were intermittent carriers. Twenty-one episodes of infection occurred in 13 patients: Ten were bacteremias (including 2 cases of endocarditis), 1 was pneumonia, and 10 were cutaneous or subcutaneous infections. Seventeen (85%) of these episodes occurred in patients with CD4 counts less than 100 cells/mm3. Recurrent infections occurred in 3 of 7 patients who survived an initial S. aureus infection. The mortality rate was higher among patients with S. aureus infection than among those without infection (P = 0.03). Factors significantly associated with S. aureus infection were nasal carriage, presence of a vascular catheter, low CD4 count, and neutropenia. Molecular strain typing indicated that for 6 of 7 infected patients, the strain of S. aureus isolated from the infected sites was the same as that previously cultured from the nares. CONCLUSION Nasal carriage is an important risk factor for S. aureus infection in HIV-infected patients. Controlled studies are indicated to determine whether eradication of nasal carriage in a selected subset of patients (for example, those with a low CD4 cell count) might prevent invasive S. aureus infection in patients with HIV infection.
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Nguyen MH, Yu CY. Influence of incubation time, inoculum size, and glucose concentrations on spectrophotometric endpoint determinations for amphotericin B, fluconazole, and itraconazole. J Clin Microbiol 1999; 37:141-5. [PMID: 9854079 PMCID: PMC84190 DOI: 10.1128/jcm.37.1.141-145.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We addressed the influence of the incubation time (24 h versus 48 h), starting inoculum size (standard inoculum size, approximately 10(3) CFU/ml, versus large inoculum size, approximately 10(4) CFU/ml), and supplementation with 2% glucose of RPMI 1640 medium on the spectrophotometric determination of the MICs of amphotericin B, fluconazole, and itraconazole. We compared the MICs determined spectrophotometrically with those determined by the standard broth macrodilution method (National Committee for Clinical Laboratory Standards approved guideline M27-A). The agreement between the results of the spectrophotometric and standard methods for amphotericin B testing was 100%; this agreement was independent of the inoculum size and incubation time. On the other hand, the agreement for the results for fluconazole testing and itraconazole testing was dependent on the inoculum size and incubation time. With large inoculum size, excellent agreement can be achieved at 24 h. With standard inoculum size, acceptable agreement can be achieved only at 48 h. In contrast to previous observations, the addition of 2% glucose did not have any significant impact on the growth density at 24 h, nor did it improve the agreement with the standard method. Furthermore, supplemental glucose might falsely elevate the MIC at 48 h.
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Zafar AB, Gaydos LA, Furlong WB, Nguyen MH, Mennonna PA. Effectiveness of infection control program in controlling nosocomial Clostridium difficile. Am J Infect Control 1998; 26:588-93. [PMID: 9836844 DOI: 10.1053/ic.1998.v26.a84773] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To report the effectiveness of use of comprehensive infection control measures to reduce the incidence of Clostridium difficile (CD) in an acute-care teaching hospital. METHODS All CD infections were reviewed by the infection control coordinator from 1987 to 1996. The Centers for Disease Control and Prevention's nosocomial infection definition was used. CD-inclusion criteria remained unchanged during the study period. Interventions were started in 1990. INTERVENTIONS The interventions used were: (1) Isolation policy-revision and enforcement, which included universal precautions policy, (2) educational program-monthly to all health care workers, (3) phenolic disinfectant for environmental cleaning, (4) triclosan (0.03%) soap for handwashing, (5) centralization of sterilization department, (6) cart-washer installation, and (7) aggressive surveillance activity. RESULTS From 1987 to 1989, before the interventions, a total of 466 CD infections (mean 155 per year) occurred. From 1990 to 1996, after the interventions, 475 infections (mean 67 per year) occurred. Incidence of CD decreased by 60% from 1990 to 1996. CONCLUSION The sustained decrease of nosocomial CD during the 7-year period demonstrated the effectiveness of aggressive infection control measures that involve multiple disciplines.
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Abstract
OBJECTIVES to describe the clinical, microbiological and pathological features of invasive sinus aspergillosis affecting immunocompetent hosts, and to identify the risk factors for mortality. METHODS we report three apparently immunocompetent patients with invasive sinus aspergillosis, and review all cases reported in the English literature since 1987, the year in which the triazole antifungal agents were introduced. RESULTS twenty-nine patients (including three of our own) were identified. The presenting symptoms were non-specific and indistinguishable from viral, bacterial or allergic causes of sinusitis. The findings on computed tomography scan were also non-specific, and histopathology and culture of sinus tissue biopsy had low yield. These factors, along with the mistaken impression that Aspergillus can only affect immunocompromised hosts, frequently delayed the diagnosis. Fifty-nine percent of patients either failed therapy or died. The following factors were associated with a poor prognosis: delayed diagnosis, intracranial extension of infection, and histopathology demonstrating hyphal invasion of blood vessel or tissue. Complete surgical extirpation was the key element of successful therapy; antifungal agents played an adjunctive role. CONCLUSIONS invasive sinus aspergillosis carries high morbidity and mortality, even in immunocompetent hosts. To improve outcome, the diagnosis must be recognized early, before the organism can invade the central nervous system or vascular structures. Aggressive surgical resection of the infected areas is of utmost importance in the management of this infection.
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