MicroRNA-150 alleviates acute myocardial infarction through regulating cardiac fibroblasts in ventricular remodeling.

OBJECTIVE: The aim of this study was to investigate the effect of microRNA-150 on the regulation of myocardial fibrosis and ventricular remodeling in rats with acute myocardial infarction (AMI). MATERIALS AND METHODS: The AMI rats model was established by the ligation of the left anterior descending coronary artery (LAD) in vivo. After AMI procedures, the rats were injected with microRNA-150 lentivirus overexpression or negative control, respectively. Cardiac function of rats was evaluated by echocardiography. Hematoxylin and eosin (HE) staining and Masson trichrome were performed to evaluate myocardial fibrosis in each rat. Meanwhile, cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) method. The expression levels of microRNA-150, col1α1, col1α2, col3 and α smooth muscle actin (α-SMA) in the border zone of rat infarct myocardium were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot, respectively. RESULTS: MicroRNA-150 expression in the border zone of infarct myocardium decreased significantly at day 28 after AMI (p<0.05). Overexpressing microRNA-150 significantly improved cardiac function, decreased collagen volume fraction (CVF) and attenuated cardiomyocyte apoptosis in rats. Furthermore, the expression levels of col1ɑ1, col1ɑ2, col3 and α-SMA in the border zone of infarct myocardium were remarkably down-regulated in rats overexpressing microRNA-150 compared with those of controls (p<0.001). CONCLUSIONS: MicroRNA-150 expression in the border zone of rat infarct myocardium decreased at day 28 after AMI. In addition, the upregulation of microRNA-150 in myocardial tissue could inhibit myocardial fibrosis and improve ventricular remodeling at post-AMI.

An expert consensus for the management of chronic hepatitis B in Asian Americans.

BACKGROUND: Hepatitis B virus (HBV) infection is common with major clinical consequences. In Asian Americans, the HBsAg carrier rate ranges from 2% to 16% which approximates the rates from their countries of origin. Similarly, HBV is the most important cause of cirrhosis, hepatocellular carcinoma (HCC) and liver related deaths in HBsAg positive Asians worldwide. AIM: To generate recommendations for the management of Asian Americans infected with HBV. METHODS: These guidelines are based on relevant data derived from medical reports on HBV from Asian countries as well as from studies in the HBsAg positive Asian Americans. The guidelines herein differ from other recommendations in the treatment of both HBeAg positive and negative chronic hepatitis B (CHB), in the approach to HCC surveillance, and in the management of HBV in pregnant women. RESULTS: Asian American patients, HBeAg positive or negative, with HBV DNA levels >2000 IU/mL (>104 copies/mL) and ALT values above normal are candidates for anti-viral therapy. HBeAg negative patients with HBV DNA >2000 IU/mL and normal ALT levels but who have either serum albumin <3.5 g/dL or platelet count <130 000 mm3 , basal core promoter (BCP) mutations, or who have first-degree relatives with HCC should be offered treatment. Patients with cirrhosis and detectable HBV DNA must receive life-long anti-viral therapy. Indications for treatment include pregnant women with high viraemia, coinfected patients, and those requiring immunosuppressive therapy. In HBsAg positive patients with risk factors, life-long surveillance for HCC with alpha-fetoprotein (AFP) testing and abdominal ultrasound examination at 6-month intervals is required. In CHB patients receiving HCC treatments, repeat imaging with contrast CT scan or MRI at 3-month intervals is strongly recommended. These guidelines have been assigned to a Class (reflecting benefit vs. risk) and a Level (assessing strength or certainty) of evidence. CONCLUSIONS: Application of the recommendations made based on a review of the relevant literature and the opinion of a panel of Asian American physicians with expertise in HBV treatment will inform physicians and improve patient outcomes.

Clinical course of chronic hepatitis B (CHB) presented with normal ALT in Asian American patients.

The clinical course for chronic hepatitis B (CHB) patients with normal ALT and with or without minimal histologic activity remains unclear. We assessed frequency, amplitude, disease activities, and associated factors of ALT and/or AST flares in this subpopulation. Forty-seven consecutive treatment naïve Asian patients with CHB were enrolled from two liver clinics between December 2003 and January 2013, who had normal baseline ALT by routine clinical biochemical testing performed 6 weeks before or after the liver biopsy. We defined a flare as elevation of ALT/AST above the upper limit of normal of ALT/AST. The mean follow-up was 37.6 (CI = 12, 88) months, and the mean age at entry into the study was 43.3 (CI = 19, 65); 22/47 (46.8%) were males; 15/45 (33.3%), HBeAg+; 68.1% had stage 0-1 fibrosis; 63.8% had grade 0-1 inflammation. During follow-up, 13/47 (27.7%) cases developed ALT flare at least once in a mean of 13.5 (CI = 2, 43) months after liver biopsy; ALT flare was not associated with baseline ALT level, fibrosis stage, inflammation grade, hepatitis B virus (HBV) DNA load, HBeAg status, HBV genotype, HBV precore and basal core promoter mutations. 11/13 (84/6%) of ALT flares resolved during follow-up. 13/13 (100%) of ALT flares met AASLD treatment criteria, but only 6/13 (46.2%) were on HBV treatment. Serum ALT and/or AST flares occur frequently in CHB carriers who initially presented with normal ALT during pretreatment period. Thus, regular follow-up is warranted despite status of ALT/AST. No clinical factors were found to be associated with ALT flares.

Response to tenofovir monotherapy in chronic hepatitis B patients with prior suboptimal response to entecavir.

Both entecavir (ETV) and tenofovir (TDF) are potent antiviral agents for hepatitis B virus (HBV). Suboptimal response (SOR) following antiviral therapy is associated with an increased risk of subsequent treatment failure and viral resistance. It remains unclear whether switching to TDF is a reasonable approach in patients with SOR to ETV treatment. This study was aimed to determine how HBV patients with SOR to ETV respond to TDF monotherapy. Data of patients with SOR to ETV (failure to achieve >1 log(10) HBV-DNA reduction during the last 24 weeks of ETV treatment) who were switched to TDF monotherapy during 2005 and 2010 were reviewed. Treatment adherence was assessed by pill-count. Fourteen patients (2.9%) were identified from a total cohort of 482 ETV-treated patients. All 14 patients were Chinese and were infected with HBV genotype C (71%) or B (29%). Nine patients were men, and the median age was 41.5 years (19-64). Twelve were treatment naïve (one lamivudine- and one peginterferon-experienced patient); 85.7% were HBeAg positive. The median baseline HBV-DNA was 7.55 (5.30-9.40) log(10) copies/mL, and 57% had abnormal serum alanine aminotransferase (ALT) levels. Precore and/or basal core promoter mutations were detected in four patients, whereas no genotypic resistance was detected at baseline and before switching to TDF. The median duration of ETV treatment was 64.5 (26-126) weeks. The median HBV-DNA at the time of switching to TDF was 3.69 (3.00-4.90) log(10) copies/mL. The median HBV-DNA reduction from baseline and during the last 6-month observation period prior to switching to TDF was 4.04 (0.51-6.06) log(10) and 0.43 (-0.09-1.13) log(10) copies/mL, respectively. After the switching to TDF, all 14 patients (100%) achieved undetectable HBV-DNA and ALT normalization within a median duration of 30 weeks. In 12 patients who were HBeAg positive, HBeAg seroconversion was observed in two patients after TDF treatment of 75- and 84-weeks duration. There was no virological breakthrough observed after switching to TDF with a median follow-up period of 50 (24-160) weeks. TDF treatment was safe and well tolerated. In conclusion, suboptimal response to ETV is rare (approximately 3%). TDF monotherapy is safe and very effective in the management of HBV patients with SOR to ETV.

Hepatitis C treatment among racial and ethnic groups in the IDEAL trial.

Previous studies of chronic hepatitis C virus (HCV) treatment have demonstrated variations in response among racial and ethnic groups including poorer efficacy rates among African American and Hispanic patients. The individualized dosing efficacy vs flat dosing to assess optimaL pegylated interferon therapy (IDEAL) trial enrolled 3070 patients from 118 United States centres to compare treatment with peginterferon (PEG-IFN) alfa-2a and ribavirin (RBV) and two doses of PEG-IFN alfa-2b and RBV. This analysis examines treatment response among the major racial and ethnic groups in the trial. Overall, sustained virologic response (SVR) rates were 44% for white, 22% for African American, 38% for Hispanic and 59% for Asian American patients. For patients with undetectable HCV RNA at treatment week 4, the positive predictive value of SVR was 86% for white, 92% for African American, 83% for Hispanic and 89% for Asian American patients. The positive predictive values of SVR in those with undetectable HCV RNA at treatment week 12 ranged from 72% to 81%. Multivariate regression analysis using baseline characteristics demonstrated that treatment regimen was not a predictor of SVR. Despite wide-ranging SVR rates among the different racial and ethnic groups, white and Hispanic patients had similar SVR rates. In all groups, treatment response was largely determined by antiviral activity in the first 12 weeks of treatment. Therefore, decisions regarding HCV treatment should consider the predictive value of the early on-treatment response, not just baseline characteristics, such as race and ethnicity.

Extended criteria donor and severe intraoperative glucose variability: association with reoperation for hemorrhage in liver transplantation.

Reoperations for hemorrhage following liver transplantation (OLT) are commonly associated with increased morbidity and mortality. We sought to determine the incidence and risk factors for reoperation for hemorrhage among adult liver transplantations. We retrospectively analyzed 668 patients transplanted between January 2004 and November 2007. Within 30 days following transplantation one hundred eleven patients (16.6%) underwent 156 reoperations for hemorrhage, averaging 1.4 reoperations per patient. More than half of the reoperations occurred during the first 2 postoperative days. One-third of patients required 2 or more reoperations. Multivariate logistic regression analysis showed 4 independent risk factors: grafts from donors with multiple extended criteria, severe intraoperative glucose variability, intraoperative use of vasopressors, and red blood cell transfusion requirement. In conclusion, we identified several independent risk factors for reoperation due to hemorrhage following OLT. Avoidance of severe intraoperative glucose variability and careful evaluation of the benefits and risks of utilizing extended criteria donors must be considered before transplantation.

Black patients with chronic hepatitis C have a lower sustained viral response rate than non-Blacks with genotype 1, but the same with genotypes 2/3, and this is not explained by more frequent dose reductions of interferon and ribavirin*.

In previous hepatitis C virus (HCV) treatment studies, Black patients not only had a lower sustained viral response (SVR) rate to interferon and ribavirin (RBV) than non-Black patients but also a higher frequency of HCV genotype 1 (GT-1) infection. The aim of this community-based study was to determine whether Black patients have a lower SVR rate independent of genotype. We prospectively enrolled 785 patients (24.8% Black, 71.5% White, 3.7% others) who received interferon alpha-2b 3 MU three times weekly + RBV 1000-1200 mg/day for 24 weeks (GT-2/3) or 48 weeks (GT-1). Black patients were more commonly infected with GT-1 (86.8%vs 64.8%, P < 0.001) and less frequently had an SVR compared with non-Black patients (8.4%vs 21.6%, P < 0.001). Within GT-1, Black patients had a lower SVR rate than non-Black patients (6.1%vs 14.1%, P = 0.004) but not within GT-2/3 (50.0%vs 36.5%, P = 0.47). Black patients had lower baseline haemoglobin levels (14.8 vs 15.3 g/dL, P < 0.001) and neutrophil counts (2900 vs 4100/mm(3), P < 0.001) and required more frequent dose reductions of RBV (29.8%vs 18.5%, P < 0.001) and interferon (4.7%vs 1.6%, P = 0.012). However, dose reductions were not associated with lower SVR rates while early treatment discontinuations were (2.9%vs 25.7%, P < 0.001). Independent predictors of SVR were GT-1 [odds ratio (OR) 0.33; 95% confidence interval (CI) 0.20-0.55; P < 0.001], Black race (OR 0.45; 95% CI 0.22-0.93; P = 0.030), and advanced fibrosis, stages 3 + 4 (OR 0.53; 95% CI 0.31-0.92; P = 0.023). In conclusion, Black patients infected with HCV GT-1 (but not GT-2/3) have a lower SVR rate than non-Black patients. This is not explained by their lower baseline haemoglobin levels and neutrophil counts that lead to higher rates of ribavirin and interferon dose reductions.

Management of ascites.

The evaluation of ascites includes a directed history, focused physical examination, and diagnostic paracentesis with ascitic fluid analysis. Dietary sodium restriction and oral diuretics are the mainstay of therapy for the majority of patients with cirrhotic ascites. Transjugular intrahepatic portocaval shunt has emerged as the treatment of choice for selected patients with refractory ascites, although serial large-volume paracenteses should be attempted first. Early diagnosis, broad-spectrum antibiotics, and albumin infusion contribute to the successful management of spontaneous bacterial peritonitis (SBP). Referral for liver transplant evaluation should be considered at the first sign of decompensation and should not be delayed until development of ominous clinical features, such as refractory ascites and SBP.

Hyperfibrinolytic activity in hospitalized cirrhotic patients in a referral liver unit.

OBJECTIVE: Increased frequency of hyperfibrinolytic activity was reported in patients with cirrhosis. However, the incidence, clinical presentation, and the parameters related to hyperfibrinolysis remain largely unknown in these patients. By utilizing euglobulin lysis time (ELT) and other clinical coagulation tests, the present study investigated the incidence of and clinical parameters related to hyperfibrinolytic activity, and assessed predicting factors to epsilon-aminocaproic acid (EACA) treatment in cirrhotic patients with hyperfibrinolysis in a liver unit. METHODS: The study included 86 consecutive patients who were referred and admitted to a referral liver unit for various liver diseases. The mean age was 50.0 yr, with a male: female ratio of 60:26. Sixty-six patients (76.7%) were Hispanic and 75 (87.2%) were cirrhotic. The etiologies of liver diseases included alcoholic liver disease (n = 68, 79.1%), hepatitis B (n = 2, 2.3%), hepatitis C (n = 6, 7.0%), autoimmune hepatitis (n = 3, 3.5%), cryptogenic liver disease (n = 4, 4.7%), and hepatocellular carcinoma (n = 3, 3.5%). Coagulation studies included ELT, PT, PTT, fibrinogen, D-dimer, and fibrin degradation product levels. RESULTS: Hyperfibrinolytic activity as reflected by shortened ELT was present in 27/75 cirrhotic (31.3%) but 0/11 noncirrhotic patients, which was significantly correlated with higher Child-Pugh (C-P) class, abnormal levels of PT, PTT, fibrinogen, platelet count, and total bilirubin. Shortened ELT was more frequently seen in patients with hepatic decompensation and mucocutaneous bleeding, although these relationships were not statistically significant. In 27 patients with hyperfibrinolysis, five (18.5%) required EACA treatment for progressive mucocutaneous bleeding and/or hematoma. EACA treatment was significantly associated with higher C-P scores; greatly shortened ELT (< or =50% of normal value); and abnormal levels of fibrinogen, total bilirubin, and PT, indicating that these factors may serve as predictors for EACA treatment. CONCLUSION: Hyperfibrinolytic activity was seen in 31.3% of patients with cirrhosis, which is correlated with higher C-P scores; abnormal PT, PTT, fibrinogen level, and platelet count; and hyperbilirubinemia. Patients who received EACA treatment usually have a more severe hyperfibrinolytic activity as indicated by shortened ELT and low level of fibrinogen, and more severe liver disease as indicated by higher C-P scores and hyperbilirubinemia.

Viral, host and interferon-related factors modulating the effect of interferon therapy for hepatitis C virus infection.

The estimated prevalence of hepatitis C virus infection in the US is approximately 1.8%. Although interferon monotherapy and combination therapy of interferon with ribavirin represent mainstay for treating HCV infection, the rate of sustained virologic response remains suboptimal. The growing evidence suggested that the clinical sequence and treatment response of chronic hepatitis C are determined by a dynamic, complex tripartite relationship among HCV infection, the host immune response, and the effect of different interferon regimens. The treatment response is associated with various viral factors including the pretreatment viral level, dynamic change of viral level during treatment, viral genotype quasispecies and nucleotide mutation in nonstructural protein 5A of hepatitis C virus. Host factors that may affect treatment response include age, gender, race, HLA alleles and the host immune responses. Interferon regimens, including type, dose, frequency and duration of treatment and combination of interferon with other anti-HCV agents also alter the therapeutic response. Understanding these complicated interaction may provide better insights into the mechanism(s) of interferon response, leading to more effective clinical application of interferon therapy.

The adhesion signaling molecule p190 RhoGAP is required for morphogenetic processes in neural development.

Rho GTPases direct actin rearrangements in response to a variety of extracellular signals. P190 RhoGAP (GTPase activating protein) is a potent Rho regulator that mediates integrin-dependent adhesion signaling in cultured cells. We have determined that p190 RhoGAP is specifically expressed at high levels throughout the developing nervous system. Mice lacking functional p190 RhoGAP exhibit several defects in neural development that are reminiscent of those described in mice lacking certain mediators of neural cell adhesion. The defects reflect aberrant tissue morphogenesis and include abnormalities in forebrain hemisphere fusion, ventricle shape, optic cup formation, neural tube closure, and layering of the cerebral cortex. In cells of the neural tube floor plate of p190 RhoGAP mutant mice, polymerized actin accumulates excessively, suggesting a role for p190 RhoGAP in the regulation of +Rho-mediated actin assembly within the neuroepithelium. Significantly, several of the observed tissue fusion defects seen in the mutant mice are also found in mice lacking MARCKS, the major substrate of protein kinase C (PKC), and we have found that p190 RhoGAP is also a PKC substrate in vivo. Upon either direct activation of PKC or in response to integrin engagement, p190 RhoGAP is rapidly translocated to regions of membrane ruffling, where it colocalizes with polymerized actin. Together, these results suggest that upon activation of neural adhesion molecules, the action of PKC and p190 RhoGAP leads to a modulation of Rho GTPase activity to direct several actin-dependent morphogenetic processes required for normal neural development.

Acute hepatitis induced by bupropion.

As an antidepressant, bupropion is considered to be a safe agent that usually causes infrequent and mild increase of serum liver enzymes. Asymptomatic elevation of serum transaminases was previously reported only in a single case. We describe a patient who developed typical acute hepatitis after receiving six weeks of bupropion for depression. His presentation was characterized with acute onset of symptoms associated with significantly elevated ALT, AST, and LDH and acute hepatic inflammation. The clinical course of our patient, including incubation period, pattern of liver enzyme elevation, and time of recovery, was similar to, but much more severe than, the case reported by Oslin and Duffy. Discontinuation of bupropion was followed by a rapid resolution of clinical symptoms and liver enzymes. The incidence of bupropion-induced hepatitis remains to be defined even though it appears to be relatively low. Since the clinical application of bupropion is broader, we must be aware of the clinical entity of bupropion-induced hepatitis.

The long-term outcomes of patients with compensated hepatitis C virus-related cirrhosis and history of parenteral exposure in the United States.

It is well known that hepatitis C virus (HCV) infection may progress to cirrhosis and is linked to the development of hepatocellular carcinoma (HCC). Previous studies have shown that compensated HCV-cirrhosis is related to a certain morbidity and mortality in European patients, but little is known in regard to the clinical outcomes of a similar group of patients in the United States. This study investigated this category of patients in terms of the incidence of decompensation, development of HCC, mortality, and the predictive risk factors for morbidity and mortality. The potential effects of interferon (IFN) therapy on outcomes of the disease also were assessed. A total of 112 patients with compensated HCV-cirrhosis and a documented history of either intravenous drug abuse (IVDA) or transfusion were consecutively enrolled. The mean follow-up interval was 4.5 (2-7.7) years. The cumulative probabilities for decompensation and development of HCC were 22.2% and 10.1% in 5 years, with an estimated yearly incidence of 4.4% and 2.0%, respectively. The cumulative survival probability was 82.8% from entry and 51.1% from decompensation in 5 years, with estimated yearly events of mortality and liver transplantation of 3.4% and 9. 8%, respectively. It was found that age at entry and initial exposure, initial levels of albumin, platelet count, and prothrombin time (PT) were predictive risk factors for developing decompensation, whereas age at entry and initial exposure, history of transfusion, lower initial levels of albumin, platelet count, and viral load were predictive risk factors for events of mortality and liver transplantation. The incidence of decompensation was significantly lower in patients treated with IFN, but age may have played a contributory role. In contrast, neither HCC development nor mortality was significantly altered by IFN therapy. In conclusion, our study indicated that patients with compensated HCV-cirrhosis in the United States progressed slowly and experienced eventual morbidity and mortality. Once decompensation develops, the disease will be more progressive and result in even higher mortality. Further studies will be required to determine the efficacy of IFN on clinical outcomes in this group of patients.

Myoblast city, the Drosophila homolog of DOCK180/CED-5, is required in a Rac signaling pathway utilized for multiple developmental processes.

The Rac and Cdc42 GTPases share several regulators and effectors, yet perform distinct biological functions. The factors determining such specificity in vivo have not been identified. In a mutational screen in Drosophila to identify Rac-specific signaling components, we isolated 11 alleles of myoblast city (mbc). mbc mutant embryos exhibit defects in dorsal closure, myogenesis, and neural development. DOCK180, the mammalian homolog of Mbc, associates with Rac, but not Cdc42, in a nucleotide-independent manner. These results suggest that Mbc is a specific upstream regulator of Rac activity that mediates several morphogenetic processes in Drosophila embryogenesis.

Tandem SH2 binding sites mediate the RasGAP-RhoGAP interaction: a conformational mechanism for SH3 domain regulation.

Many cellular signaling proteins contain SH3 (Src homology 3) domains that mediate protein interactions via specific proline-containing peptides. Unlike SH2 domains, whose interactions with tyrosine-containing peptides are promoted by phosphorylation of the SH2 binding site, the regulatory mechanism for SH3 interactions is unclear. p120 RasGAP (GTPase-activating protein), which contains an SH3 domain flanked by two SH2 domains, forms an abundant SH2-mediated complex with p190 RhoGAP in cells expressing activated tyrosine kinases. We have identified two closely linked tyrosine-containing peptides in p190 that bind simultaneously to the RasGAP SH2 domains upon p190 phosphorylation. This interaction is expected to bring the two SH2 domains into close proximity. Consequently, RasGAP undergoes a conformational change that results in a 100-fold increase in the accessibility of the target binding surface of its SH3 domain. These results indicate that the tandem arrangement of SH2 and SH3 domains found in a variety of cellular signaling proteins can provide a conformational mechanism for regulating SH3-dependent interactions through tyrosine phosphorylation. In addition, it appears that the role of p190 in the RasGAP signaling complex is to promote additional protein interactions with RasGAP via its SH3 domain.

Identification of a novel human Rho protein with unusual properties: GTPase deficiency and in vivo farnesylation.

We have identified a human Rho protein, RhoE, which has unusual structural and biochemical properties that suggest a novel mechanism of regulation. Within a region that is highly conserved among small GTPases, RhoE contains amino acid differences specifically at three positions that confer oncogenicity to Ras (12, 59, and 61). As predicted by these substitutions, which impair GTP hydrolysis in Ras, RhoE binds GTP but lacks intrinsic GTPase activity and is resistant to Rho-specific GTPase-activating proteins. Replacing all three positions in RhoE with conventional amino acids completely restores GTPase activity. In vivo, RhoE is found exclusively in the GTP-bound form, suggesting that unlike previously characterized small GTPases, RhoE may be normally maintained in an activated state. Thus, amino acid changes in Ras that are selected during tumorigenesis have evolved naturally in this Rho protein and have similar consequences for catalytic function. All previously described Rho family proteins are modified by geranylgeranylation, a lipid attachment required for proper membrane localization. In contrast, the carboxy-terminal sequence of RhoE predicts that, like Ras proteins, RhoE is normally farnesylated. Indeed, we have found that RhoE in farnesylated in vivo and that this modification is required for association with the plasma membrane and with an unidentified cellular structure that may play a role in adhesion. Thus, two unusual structural features of this novel Rho protein suggest a striking evolutionary divergence from the Rho family of GTPases.

Detection of hepatitis C virus with RNA polymerase chain reaction in fulminant hepatic failure.

The role of hepatitis C virus (HCV) infection in fulminant hepatic failure is controversial. The frequency of serum HCV RNA positivity in previously reported patients with fulminant hepatic failure (FHF) of indeterminate cause ranged from 0 to 12% in the United States and Europe and from 43% to 59% in Asia. We assessed serum HCV RNA using polymerase chain reaction (PCR) and oligoprimers from the 5'UTR of the HCV genome in 26 consecutive patients with FHF. Another laboratory independently performed PCR on 21 of the serum samples using different oligoprimers from the 5'UTR and NS3 region of the HCV genome. Serum HCV RNA was detected in two of seven (28%) patients with hepatitis B, 9 of 15 (60%) with an indeterminate cause, and in none with hepatitis A (n = 2) or drug-induced hepatotoxicity (n = 2). HCV RNA PCR results were concordant between both laboratories in 17 of 21 (81%) of samples. In patients with an indeterminate cause, HCV RNA positivity was significantly associated with the transmission risk factor of low socioeconomic status and Hispanic ethnicity. Eighteen patients underwent liver transplantation (LT) and 15 (83%) survived. Among patients with FHF of indeterminate cause, recurrent or acquired HCV infection after transplantation occurred in three of five (60%) and one of four (25%) patients, respectively. Three of four (75%) patients with hepatitis C virus infection post-LT also developed histologic hepatitis. HCV appears to be the causative agent of a substantial number of cases of FHF classified as indeterminate in the Los Angeles area. Differences in patient populations or risk factors may explain the discordant incidences of HCV infection in FHF observed among different programs.

Simultaneous detection of both hepatitis B virus DNA and hepatitis C virus RNA using a combined one-step polymerase chain reaction technique.

Hepatitis C virus (HCV) RNA polymerase chain reaction (PCR) is widely used for diagnosis of HCV infection and evaluation of therapy. The sensitive hepatitis B virus (HBV) DNA PCR is often reserved for detection of quantities of HBV DNA that are insufficient for hybridization. Application of both PCR techniques is limited by their labor-intensity, potential for contamination, and substantial time required for analysis. To study HCV and HBV infections, occurring alone or in combination, we developed a combined one-step PCR method to detect HCV RNA and HBV DNA in a single serum specimen using oligoprimers from the HCV 5' untranslated region and the HBV preS/S region. Specificity of the HBV and HCV PCR products was confirmed on the basis of their molecular sizes in positive samples, Southern blot hybridization, and negative controls. The sensitivities of the combined PCR were assessed using samples containing a wide range of defined amounts of HBV DNA and HCV RNA and were comparable with those obtained with conventional HBV DNA or HCV RNA PCR methods. The sensitivity of the combined method was further validated by the 100% concordance between results of its HBV and HCV components and those of conventional PCR methods in patients with HBV and/or HCV infections. The combined one-step HBV/HCV PCR is a sensitive, specific, rapid, and cost-effective method, especially suited for epidemiological screening and clinical diagnosis of HBV and HCV infections occurring alone or in combination.

Characterization of rho GTPase family homologues in Drosophila melanogaster: overexpressing Rho1 in retinal cells causes a late developmental defect.

The rho family of GTPases has been implicated in regulating changes in cell morphology in response to extracellular signals. We have cloned three widely expressed members of this family from Drosophila melanogaster; a rho homologue (Rho1) and two rac homologues (Rac1 and Rac2). Flies harbouring a Rho1 transgene that is specifically expressed in the eye exhibit a dramatic dose dependent disruption of normal eye development. Flies bearing at least two copies of the transgene display a severe rough eye phenotype characterized by missing secondary and tertiary pigment cells, a substantial reduction in the number of photoreceptor cells and a grossly abnormal morphology of the rhabdomeres. Cell fate determination in the imaginal disc occurs normally and abnormalities become manifest late in pupariation, coincident with the phase when the cells undergo major morphological changes. This phenotype is modified by mutations at several other loci that have been implicated in signal transduction, but not by mutations in ras pathway components.