PubMed Health⌕ Search

Biomedical subjects

M Sherman

Publications and source records attributed to M Sherman.

At least 19 recordsLinked to original sources
PubMed2006

Requirement for Akt-mediated survival in cell transformation by the dbl oncogene.

The dbl oncogene product is the founding member of a large family of oncogenic proteins that function by activating the small GTP-binding proteins Cdc42, Rac and Rho. Through its substrate GTPases, Dbl transduces proliferative signals from cell-surface receptors to diverse cellular effectors and signaling pathways. The mechanisms by which these multiple signals are integrated, as well as their relative contribution to Dbl-induced cell transformation, are presently poorly understood. We investigated the role of the survival regulators PI3-kinase and Akt in Dbl-induced cell transformation. We found that Dbl induced the phosphorylation of Akt on threonine 308, through the GTPases Rac and Cdc42 and in a PI3-kinase dependent manner. Pharmacological or biochemical interference with this pathway lead to a marked, dose-dependent inhibition of the focus formation activity exhibited by Dbl-expressing cells. Dbl expression stimulated the phosphorylation of the anti-apoptotic Akt substrate Bad, and caused a marked decrease in basal levels of apoptosis. Finally, we found that activated Cdc42 existed in cells in complex with phosphoionositide-dependent kinase-1 (PDK1), the downstream mediator of PI3-kinase action. The data indicate that Dbl signaling stimulate the formation of a novel survival complex, through which anti-apoptotic signals are generated and propagated.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed2006

Peginterferon alfa-2a (40KD) plus ribavirin in chronic hepatitis C patients who failed previous interferon therapy.

BACKGROUND: The management of patients with chronic hepatitis C who have relapsed or failed to respond to interferon based therapies is an important issue facing hepatologists. AIMS: We evaluated the efficacy and safety of peginterferon alfa-2a (40KD) plus ribavirin in this population by conducting a multicentre open label study. PATIENTS: Data from adults with detectable serum hepatitis C virus (HCV) RNA who had not responded or had relapsed after previous conventional interferon or conventional interferon/ribavirin combination therapy were analysed. METHODS: Patients were retreated with peginterferon alfa-2a (40KD) 180 microg/week plus ribavirin 800 mg/day for 24 or 48 weeks at the investigators' discretion. The study was conceived before the optimal dose of ribavirin (1000/1200 mg/day) for patients with genotype 1 was known. The primary endpoint was sustained virological response (SVR), defined as undetectable HCV RNA (<50 IU/ml) after 24 weeks of follow up. The analysis was conducted by intention to treat. RESULTS: A total of 312 patients (212 non-responders, 100 relapsers) were included. Of these, 28 patients were treated for 24 weeks and 284 for 48 weeks. Baseline characteristics between non-responders and relapsers were similar although more non-responders had genotype 1 infection (87% v 69%). Overall SVR rates were 23% (48/212) for non-responders and 41% (41/100) for relapsers. When data were analysed by genotype, SVR rates were 24% (61/253) in genotype 1 and 47% (28/59) in genotype 2/3. CONCLUSIONS: These results in a large patient cohort demonstrate that it is possible to cure a proportion of previous non-responders and relapsers by retreating with peginterferon alfa-2a (40KD) plus ribavirin.

Adult↗
PubMed2006

Personal view: the management of chronic hepatitis B infection.

There are two new nucleoside analogues available for the management of chronic hepatitis B, adefovir and entecavir, and several more in development. In addition, pegylated interferon has become available. Large-scale population studies have re-emphasized the significance of viral load in predicting a poor outcome over the longer term. These new developments have prompted a reassessment of the indications and objectives of therapy for chronic hepatitis B. Hepatitis B virus deoxyribonucleic acid, rather than alanine aminotransferase should be the prime indication for therapy. Hepatitis B e antigen seroconversion can be achieved in 30-40% of treated patients whatever agent is used. However, it takes longer for nucleoside analogues to achieve the same seroconversion rates as interferon. In anti-HBe-positive disease long-term therapy is required for most patients because the relapse rate after withdrawal of therapy is very high, irrespective of the agent used. Viral resistance limits the use of lamivudine, and to a lesser extent adefovir. Resistance to entecavir has so far only been described in pre-existing lamivudine resistance. Although therapy with combinations of nucleoside analogues has not been investigated to any extent, this is the only way to reduce the emergence or resistance, and studies are urgently needed.

Adenine↗
PubMed2006

Treating chronic hepatitis C with pegylated interferon alfa-2a (40 KD) and ribavirin in clinical practice.

BACKGROUND: Pegylated interferon alfa-2a (40 KD) plus ribavirin therapy induces sustained virological response rates up to 63% in randomized-controlled trials. AIM: To conduct a prospective open-label programme to examine the efficacy and safety of this therapy in routine clinical practice. METHODS: Treatment-naive patients with chronic hepatitis C received, at the discretion of the investigator, pegylated interferon alfa-2a 180 microg/week + ribavirin 800 mg/day for 24 or 48 weeks. In total, 508 patients were enrolled [334 non-cirrhotic; 174 cirrhotic (defined as stage F3 and F4)]. RESULTS: In genotype 1 patients treated for 48 weeks, sustained virological response rates were 41% in non-cirrhotics and 34% in cirrhotics. Sustained virological response rates in genotype 2 or 3 non-cirrhotics were 79% (24 weeks) and 72% (48 weeks). Corresponding values for cirrhotic genotype 2/3 were 66% and 44%. The negative predictive value of an early virological response at week 12 was 94%. Predictive factors for sustained virological response on multivariate analysis were genotype (2/3 vs. 1), low viral load and degree of fibrosis. Rates of serious adverse events (<or=5%) and adverse events inducing withdrawal (<or=8%) were comparable with the phase III trials. CONCLUSION: Efficacy and safety of pegylated interferon alfa-2a + ribavirin in clinical practice is comparable with results of randomized-controlled trials.

Adult↗
PubMed2006

Transarterial chemoembolisation for advanced hepatocellular carcinoma: results from a North American cancer centre.

AIMS: In Asian countries, transarterial chemoembolisation (TACE) has long been used for palliation of unresectable hepatocellular carcinoma (HCC) without strong evidence of improved survival or quality of life. In 2002, a survival benefi of TACE was shown in two randomised controlled trials in Europe and Hong Kong. The effectiveness of interventions fo HCC is influenced by geographical factors related to diverse patient characteristics and protocols. Therefore, the validation of TACE as palliative modality for unresectable HCC requires confirmation in diverse patient populations. The aim of the present study was to assess the effectiveness of TACE for HCC in a North American population. MATERIALS AND METHODS: This was a single centre prospective cohort study. Child-Pugh A cirrhosis or better patients wit unresectable HCC and without radiological evidence of metastatic disease or segmental portal vein thrombosis wer assessed between November 2001 and May 2004. Of 54 patients who satisfied the inclusion criteria, 47 underwent 80 TACE sessions. Chemoembolisation was carried out using selective hepatic artery injection of 75 mg/m(2) doxorubicin and lipiodol followed by an injection of embolic particles when necessary. Repeat treatments were carried out at 2-3 month intervals for recurrent disease. The primary outcome was overall survival; secondary outcomes were morbidity and tumour response. RESULTS: The survival probabilities at 1, 2 and 3 years were 76.6, 55.5 and 50%, respectively. At 6 months after the first intervention, 31% of patients had a partial response and 60% had stable disease by RECIST criteria. Minor adverse events occurred after 39% of TACEs and major adverse events after 20% of sessions, including two treatment-related deaths (4% of patients). One patient had complete cancer remission after undergoing three TACE treatments. Further progression of tumour growth was prevented in 91% of tumours at the 6 month point after the first TACE. At 3 months, serum levels of the tumour marker alpha-feto protein were significantly reduced in patients with elevated levels before TACE. CONCLUSIONS: The survival probabilities at 1 and 2 years after TACE were comparable with results in randomised studies from Europe and Asia. Most patients tolerated TACE well, but clinicians need to be aware that moderately severe sideeffects require close monitoring and prompt intervention.

Aged↗
PubMed2004

A multicentre study of the usefulness of liver biopsy in hepatitis C.

The role of liver biopsy in the assessment of chronic hepatitis C is generally accepted yet there is no prospective data available to quantify its contribution. A previous single centre pilot study suggested that the clinician could predict the amount of fibrosis and to a lesser extent, inflammation with moderate accuracy. The 2002 National Institute of Health Hepatitis C Consensus Conference recommended further study of the role of liver biopsy. Our objective was to compare a prediction of biopsy findings by expert clinicians using usually available clinical and laboratory data to actual biopsy results in order to determine whether biopsy is required routinely. This was a prospective observational study conducted at seven university centres in which the accuracy of clinician's predictions of the degree of inflammation and fibrosis were compared with the actual liver biopsy using an adaptation of a standard histological scoring system. We studied 81 adults with previously untreated chronic hepatitis C, raised serum transaminases and positive HCV-RNA in serum. Clinicians predicted the inflammatory grade in 44 of 80 cases (55%) and the fibrosis stage in 46 of 81 cases (57%). Nine of 17 cirrhotic cases were predicted (sensitivity 53%, specificity 56%). No unexpected additional diagnoses were made on the biopsies. Thus despite knowledge of the clinical and laboratory investigations of patients with hepatitis C, clinicians are unable to accurately predict the hepatic inflammatory grade and fibrotic stage. Liver biopsy is an essential investigation to accurately evaluate the grade and stage of liver disease patients with hepatitis C.

Adult↗
PubMed2002

Staging of hepatocellular carcinoma: assessment of the CLIP, Okuda, and Child-Pugh staging systems in a cohort of 257 patients in Toronto.

BACKGROUND: A new staging system for hepatocellular carcinoma (HCC) has recently been reported from Italy (CLIP classification). It combines Child-Pugh staging with tumour criteria: tumour morphology, portal invasion, and alpha fetoprotein levels. AIMS: To validate the use of the CLIP staging in a cohort of HCC patients and compare it with Okuda staging. PATIENTS AND METHODS: A retrospective analysis of patients with HCC diagnosed in the Toronto General Hospital between October 1994 and December 1998. RESULTS: A total of 313 patients were identified; 19 patient with insufficient data and 37 transplant patients were excluded. Hence 257 patients in whom complete data for clinical staging were available were included in the study. The median survival of the cohort was 22.8 months. The CLIP stage 0 group (23.1% of the cohort) and the Okuda stage 1 group (50.7% of the cohort) had a five year survival rate of 67% and 35%, respectively (p<0.02). The CLIP stage 0 criteria more accurately defined patients with a good prognosis. The Okuda classification failed to identify two thirds of the 37 patients with a poor prognosis, who were identified by the CLIP criteria. Patients with a CLIP score > or =4 shared a very poor prognosis (median survival 1-3 months). Further classification above stage 4 was unnecessary. SUMMARY: The CLIP classification for HCC is easy to implement and more accurate than the Okuda classification. Our cohort was different from the CLIP cohort (more hepatitis B) but the results were still consistent.

Carcinoma, Hepatocellular↗
PubMed2001

The outbreak of West Nile virus infection in the New York City area in 1999.

BACKGROUND: In late August 1999, an unusual cluster of cases of meningoencephalitis associated with muscle weakness was reported to the New York City Department of Health. The initial epidemiologic and environmental investigations suggested an arboviral cause. METHODS: Active surveillance was implemented to identify patients hospitalized with viral encephalitis and meningitis. Cerebrospinal fluid, serum, and tissue specimens from patients with suspected cases underwent serologic and viral testing for evidence of arboviral infection. RESULTS: Outbreak surveillance identified 59 patients who were hospitalized with West Nile virus infection in the New York City area during August and September of 1999. The median age of these patients was 71 years (range, 5 to 95). The overall attack rate of clinical West Nile virus infection was at least 6.5 cases per million population, and it increased sharply with age. Most of the patients (63 percent) had clinical signs of encephalitis; seven patients died (12 percent). Muscle weakness was documented in 27 percent of the patients and flaccid paralysis in 10 percent; in all of the latter, nerve conduction studies indicated an axonal polyneuropathy in 14 percent. An age of 75 years or older was an independent risk factor for death (relative risk adjusted for the presence or absence of diabetes mellitus, 8.5; 95 percent confidence interval, 1.2 to 59.1), as was the presence of diabetes mellitus (age-adjusted relative risk, 5.1; 95 percent confidence interval, 1.5 to 17.3). CONCLUSIONS: This outbreak of West Nile meningoencephalitis in the New York City metropolitan area represents the first time this virus has been detected in the Western Hemisphere. Given the subsequent rapid spread of the virus, physicians along the eastern seaboard of the United States should consider West Nile virus infection in the differential diagnosis of encephalitis and viral meningitis during the summer months, especially in older patients and in those with muscle weakness.

Adolescent↗
PubMed2001

Molecular basis for the constitutive activity of estrogen-related receptor alpha-1.

Some orphan nuclear receptors, including estrogen-related receptor alpha-1 (ERRalpha-1), can activate gene transcription in a constitutive manner. Little is known about the molecular basis of the constitutive activity of these receptors. Our results from site-directed mutagenesis experiments have revealed that Phe-329 (analogous to Ala-350 in estrogen receptor alpha (ERalpha)) is responsible for the constitutive activity of ERRalpha-1. The ERRalpha-1 mutant F329A lost the transactivation activity and acted as a dominant negative mutant. The mammalian cell transfection experiments revealed that the ERRalpha-1 mutant F329A, like wild-type ERalpha, recognized toxaphene (an organochlorine pesticide) as an agonist. This compound was previously shown to be an antagonist of wild-type ERRalpha-1. On the other hand, like wild-type ERRalpha-1, the ERalpha mutant A350F was found to be constitutively active (as demonstrated by mammalian cell transfection and yeast two-hybrid assays). These results indicate that Phe-329 in ERRalpha-1 and Ala-350 in ERalpha play important roles in both ligand binding and transactivation function.

Alanine↗
PubMed2001

Prevalence of HTLV-I-associated T-cell lymphoma.

In order to assess the prevalence rate of HTLV-1-associated T-cell lymphomas and human retrovirus infection in general, approximately 21,000 individuals representing various patient populations, retroviral risk groups, and blood donors were examined for HTLV-I, HTLV-II, HIV-1, or HIV-2 infection using serologic and PCR assays. The prevalence rates among volunteer blood donors were 0.02% and 0% for HTLV and HIV, respectively. Significantly increased HTLV prevalence rates were observed among paid blood donors, African American health care clinic patients, Amerindians, recipients of HTLV-positive cellular blood products, intravenous drug users, sexual contacts and family members of HTLV-positive people, and patients with primary thrombocytosis and other-than-low-grade non-Hodgkin's lymphoma (NHL). Among some of these groups there were significant differences in the prevalence of HTLV-I versus HTLV-II. The eight HTLV-positive NHL patients all had mature, high-grade, CD4+ T-cell lymphomas with clonally integrated HTLV-I, for a prevalence of 4% among other-than-low-grade NHL patients. Seven of the eight died from their disease within 2 years despite treatment. Interestingly, two groups at risk for HTLV infection, namely needle stick victims and recipients of HTLV-infected and/or pooled plasma products, showed no evidence for infection. Significantly increased HIV-1 prevalence was observed among paid blood donors, African Americans, homosexuals, female prostitutes, hemophiliacs, and other-than-low-grade NHL patients. Only one patient was infected with HIV-2. Of the nine HIV-positive, other-than-low-grade NHL patients, seven HIV-1 positives had B-cell lymphomas, one HIV-1 positive had an HTLV-I-positive CD4+ T-cell lymphoma, and one infected with HIV-2 had a CD4+ T-cell lymphoma that was HTLV negative. The data indicate that HTLV-I lymphoma, while uncommon, is not necessarily rare among other-than-low-grade NHL cases in the United States and, given its poor prognosis, should probably be studied separately in clinical trials.

Black or African American↗
PubMed2001

Surveillance for hepatocellular carcinoma.

Surveillance for hepatocellular carcinoma (HCC) in patients with recognized risk factors remains controversial. The populations for whom surveillance may be appropriate include all patients with established cirrhosis, and hepatitis B (HBV) carriers, even in the absence of cirrhosis. However, even these risk groups can be stratified into patients with higher or lower risk. The most appropriate surveillance test is periodic ultrasound examination, although the optimum screening interval has not been defined. Alphafetoprotein (AFP) is a poor surveillance test, lacking in sensitivity and specificity. There are no randomized controlled trials confirming that surveillance for HCC reduces disease-specific mortality. Modeling studies, however, have suggested that screening is cost-effective and reduces group mortality by a small amount. The criteria by which cancer surveillance programs in general can be judged have been described. Surveillance for HCC meets some of these criteria, but not all. In particular, more effective treatments have to be developed to improve the outcome of surveillance. Although there is no firm evidence to support the practice of surveillance for HCC, this has become common practice, forever preventing the definitive study from being performed. Nonetheless, surveillance is recommended in order to identify patients with small HCCs, who can be entered into trials of therapy of these tumors.

Carcinoma, Hepatocellular↗
PubMed2001

Pilot study of interferon-alpha and ribavirin treatment in patients with chronic hepatitis C and normal transaminase values.

Combination interferon-alpha (IFN-alpha) and ribavirin treatment has become standard therapy for patients with chronic hepatitis C and elevated transaminase levels (> 1.5 x upper limit of normal). No previous study has specifically examined the efficacy of this treatment in patients with normal transaminase values. In this pilot study, we treated 19 patients, with normal or near-normal ALT values on at least three occasions, and histologically mild disease, with induction IFN-alpha2b, 5 mega units daily for 4 weeks, then 3 mega units thrice weekly for 44 week, plus concomitant ribavirin 1000 mg or 1200 mg daily for 48 weeks. Nine of the 19 (47%) showed sustained virological response, defined as undetectable HCV-RNA at 24 weeks after the end of treatment. No ALT flares were observed in any patient. We conclude that combination induction IFN-alpha and ribavirin therapy may be effective in patients with normal-ALT, and appears not to induce flares of ALT activity. Controlled trials of this treatment in this subgroup of patients with hepatitis C are warranted.

Adolescent↗