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Biomedical subjects

David Kershenobich

Publications and source records attributed to David Kershenobich.

17 recordsLinked to original sources
PubMed2006

Colchicine delays the development of hepatocellular carcinoma in patients with hepatitis virus-related liver cirrhosis.

BACKGROUND: Hepatocellular carcinoma (HCC) is a malignant neoplasm associated with liver cirrhosis, with an annual incidence of 3% to 9%, which is one of the main causes of death in patients with cirrhosis. Viral hepatitis is associated with an increased risk of HCC, probably due to an inflammatory reaction. Colchicine is an antiinflammatory agent that inhibits the formation of intracellular microtubules, affecting mitosis and fibrogenesis. Diverse clinical studies have failed to demonstrate the benefit of colchicine over the progression of fibrosis in patients with liver cirrhosis; nevertheless, to the authors' knowledge there are no studies that evaluate its effect in the development of HCC. METHODS: The effect of the administration of colchicine on the development of HCC was evaluated in 186 patients with hepatitis virus-related liver cirrhosis in a retrospective cohort study. The minimum follow-up time was 3 years (median, 84 months +/- 2.8 months). One hundred sixteen patients received treatment with colchicine. The characteristics of both groups were similar. RESULTS: The percentage of patients who developed HCC was significantly smaller in the colchicine group when compared with the noncolchicine group (9% vs. 29%; P = .001). On multivariate analysis, an alpha-fetoprotein level > or = 5 ng/dL (P = .03), a platelet count < 100,000 at diagnosis (P = .05), alanine aminotransferase > or = 52 IU (P = .006), and a lack of treatment with colchicine (P = .0001) were found to be associated with an earlier development of HCC. The average time for the development of HCC was 222 months +/- 15 months and 150 months +/- 12 months in the patients who received and who did not receive colchicine, respectively. CONCLUSIONS: The results suggest that treatment with colchicine prevents and delays the development of HCC in patients with hepatitis virus-related cirrhosis. The protective mechanisms of colchicine over the development of HCC could be related to antiinflammatory properties and inhibition of mitosis. Prospective studies to confirm this observation with a greater number of patients and long-term follow-up may be indicated.

Adult↗
PubMed2006

Association of alcohol-metabolizing genes with alcoholism in a Mexican Indian (Otomi) population.

Association studies provide a powerful approach to link DNA variants and genetic predisposition to complex diseases. In this study, we determined the genotype and allelic frequencies of genes encoding enzymes involved in alcohol metabolism in alcoholic and nonalcoholic subjects of related ethnicity. A total of 118 individuals of Otomi Mexican Indian ancestry were included. Fifty-nine were chronic alcoholics according to WHO criteria and alcohol dependents according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM IV) criteria. They were compared to 59 teetotalers or alcohol consumers of <10 g per day. The restriction fragment length polymorphisms analyzed were ADH1B/MaeIII, ALDH2/MboII, CYP2E1/DraI, CYP2E1/RsaI, and CYP2E1/TaqI. Of the studied polymorphisms, a significant difference between alcoholic and nonalcoholic Otomies was observed only in the CYP2E1/TaqI. The common genotype in alcoholics was A1/A2 (54%), and in nonalcoholics the homozygous A2/A2 (63%) (odds ratio [OR]: 0.28; 95% confidence interval [CI]: 0.13-0.60; P=.002). The frequency of the mutant allele A1 was significantly higher in alcoholics than in nonalcoholics (41 vs. 21%; OR: 2.4; 95% CI: 1.3-4.3; P=.003). This documents the presence of a polymorphism of CYP2E1 that is overexpressed in alcoholic Otomies, in which the variant allele (A1 of CYP2E1/TaqI) is associated with increased susceptibility to alcoholism. The appreciation that this finding may be an additional factor contributing to the high frequency of liver cirrhosis in Otomies requires further investigation.

Adult↗
PubMed2005

Differential effect of interleukin-10 on hepatocyte apoptosis.

Current data suggests that hepatocyte apoptosis is an essential feature contributing to several chronic liver diseases. It has been shown that IL-10 has diverse and potentially pleiotropic actions that suggest that it may have a direct effect on apoptosis. It has been established that NF-kappaB activation is essential to protect hepatocytes from apoptosis. The purpose of the present work is to evaluate the effect of the anti-inflammatory cytokine, IL-10 on the activation of NF-kappaB in primary cultured rat hepatocytes and hepatoblastoma (HepG2) cell line and explore its consequences on apoptosis. Apoptosis was induced by TNF-alpha and cicloheximide in HepG2 hepatoblastoma cells and by ethanol and a glutathione depletor in primary cultured rat hepatocytes. NF-kappaB activation was determined by EMSA. IL-10 increased ethanol induced apoptosis in primary culture rat hepatocytes (28%). These effects were enhanced when the cells were pre-treated with IL-10 under conditions of oxidative stress (glutathione depletion). The effects of IL-10 on primary cultured hepatocytes were independent of NF-kappaB activation. When apoptosis was induced by cicloheximide and TNF-alpha in hepatoblastoma cells, pretreatment with IL-10 was accompanied by a decrease of 38% in apoptosis. IL-10 did not have any effect on the signaling cascade of apoptosis but caused a significant increase in NF-kappaB activation. When NF-kappaB activation was inhibited by sulfazalazine the decrease in apoptosis was reversed. The present study demonstrates the importance of differential cell marking when trying to characterize the effects of cytokines in their contribution to liver cell apoptosis. The study provides insight into the mechanisms by which IL-10 affects apoptosis through a differential effect on NF-kappaB activation.

Animals↗
PubMed2005

Differential modulation of interleukin 8 by interleukin 4 and interleukin 10 in HepG2 cells treated with acetaldehyde.

BACKGROUND/AIM: Pro-inflammatory cytokines and chemokines, such as interleukin (IL) 8, are important mediators of hepatic injury and repair following an insult. The purpose of this work was to study the regulation of IL-8 by IL-10 and IL-4 in HepG2 cells treated with acetaldehyde (Ac). METHODS: HepG2 cells were pretreated with IL-10 or IL-4 before exposure to Ac, examining IL-8 expression by reverse transcription polymerase chain reaction and Western blot. RESULTS: Ac treatment produced an increment in IL-8 induction and secretion that was prevented by IL-4 pretreatment, while IL-10 pretreatment failed to decrease Ac-induced IL-8 production. Consistent with these findings Ac increased NF-kappa B and AP-1 activation that were prevented by IL-4 but not by IL-10, findings accompanied by greater I kappa B-alpha levels in IL-4 but not IL-10 pretreated cells. In contrast to the pro-inflammatory role of IL-10 in HepG2, IL-10 did not show any change in the activation of NF-kappa B by Ac in WRL-68 cells, a human fetal hepatic cell line. Moreover, IL-10 did not induce the degradation of I kappa B-alpha in cellular extract from rat primary cultured cells. CONCLUSIONS: While the present findings demonstrate the anti-inflammatory role of IL-4 in preventing the expression of IL-8 by Ac, the regulation of chemokines by anti-inflammatory cytokines is complex and depends on the cellular lineage.

Acetaldehyde↗
PubMed2004

Matching strategies for genetic association studies in structured populations.

Association studies in populations that are genetically heterogeneous can yield large numbers of spurious associations if population subgroups are unequally represented among cases and controls. This problem is particularly acute for studies involving pooled genotyping of very large numbers of single-nucleotide-polymorphism (SNP) markers, because most methods for analysis of association in structured populations require individual genotyping data. In this study, we present several strategies for matching case and control pools to have similar genetic compositions, based on ancestry information inferred from genotype data for approximately 300 SNPs tiled on an oligonucleotide-based genotyping array. We also discuss methods for measuring the impact of population stratification on an association study. Results for an admixed population and a phenotype strongly confounded with ancestry show that these simple matching strategies can effectively mitigate the impact of population stratification.

Case-Control Studies↗
PubMed2003

Interleukin 8 response and oxidative stress in HepG2 cells treated with ethanol, acetaldehyde or lipopolysaccharide.

The aim of this work was to study the induction and secretion of interleukin 8 (IL-8) and some oxidative stress parameters after ethanol (EtOH), acetaldehyde (Ac) or lipopolysaccharide (LPS) treatment on HepG2 cells. Cells were treated with 50 mM EtOH, 175 &mgr;M Ac or 1 &mgr;g/ml of LPS. IL-8 induction and secretion were determined in the presence of the toxics, and the effect of antioxidants N-acetyl-L-cysteine and 1,1,3,3-tetramethyl-2-thiourea was evaluated. Further, the effect of adding polyclonal anti-human tumor necrosis factor alpha (TNF-alpha) and H(2)O(2) was studied, and catalase, superoxide dismutase and glutathione peroxidase activities were determined. Lipid peroxidation increased significantly only in Ac-treated cells. All toxics failed to decrease significantly the intracellular levels of reduced GSH. Catalase activity was diminished in all treatments, while other enzyme activities did not present changes. No change in peroxide production was found with any treatment. IL-8 secretion increased in Ac (41%) and in LPS (38%)-treated cells. Antioxidant and anti-TNF-alpha treatments decreased IL-8 secretion. H(2)O(2) (0.25 mM)-treated cells increased IL-8 secretion. IL-8 reverse transcriptase-polymerase chain reaction results correlated with secretion values. Our results show that Ac and LPS treatment produced an increased IL-8 induction and secretion. Oxidative stress and TNF-alpha are mediators in IL-8 response. This observation suggests that in the in vivo liver, the mechanism of ethanol-induced IL-8 production requires ethanol metabolism, and hepatocytes do not require the interaction among different populations of liver cells to respond.

Journal Article↗
PubMed2002

Trefoil factor 1 (TFF1/pS2) deficiency activates the unfolded protein response.

BACKGROUND: The trefoil factor 1 (TFF1/pS2) is a secreted gastrointestinal peptide that is often altered or lost in human gastric cancers. Consistently, mouse TFF1 deficiency leads to antropyloric tumors. MATERIALS AND METHODS: To investigate the gene expression alterations in response to the lack of TFF1, we performed differential expression analyses of TFF1 null antropyloric tumors using an array containing 588 cDNAs. RESULTS: Using total and enriched probes, 22 genes were found to be up-regulated. The identification of the genes for endoplasmic reticulum (ER)-resident GRP78, ERp72, and p58IPK proteins connected TFF1 deficiency to the unfolded protein response (UPR). Accordingly, CHOP10, a transcription factor induced early in response to ER stress, and the pleiotropic Clusterin, involved in protein folding, were also overexpressed. Northern blot analyses of 8 weeks and 1 year TFF1 null tumors confirmed that GRP78, ERp72, p58IPK, CHOP10, and Clusterin overexpression is a common and permanent feature shared by all TFF1 null antropyloric tumors. Finally, consistent with UPR, ultrastructural analyses showed that tumor rough ER was enlarged and contained dense material, supporting the hypothesis that TFF1 deficiency leads to the accumulation of misfolded proteins in the ER. CONCLUSION: Together, our data provide the first evidence of a relationship between a member of the TFF family and the ER machinery. Whereas to date TFF1 is believed to act as an extracellular molecule, our results suggest a possible additional function for TFF1 in protein folding and/or secretion.

Animals↗
PubMed2002

[Mechanisms and cofactors of hepatitis C fibrosis].

The development of quantitative methods to measure the degree of necrosis, inflammation and fibrosis in liver biopsies favored the knowledge of the natural course of liver fibrosis. Two of the most important methods are the Knodell index and the Metavir index. These indexes are also useful to monitor the effects of the diverse therapeutic alternatives. There are no satisfactory studies that confirm why progression of fibrosis is slower in women, or why it's faster when the diagnosis is made at an older age. All the therapeutic schemes decrease the progression of fibrosis, in at least one degree compared with the degree of fibrosis before the treatment. Moreover, combination therapy with pegylated interferon and ribavirin reduces the progression of fibrosis even more in patients with hepatitis C.

Hepatitis C↗
PubMedDate not supplied

Emerging concepts in inflammation and fibrosis.

Hepatic and pancreatic response to several insults commonly includes similar pathways of inflammation, fibrogenesis/regeneration, which may occur simultaneously and without appropriate coordination, resulting in chronic inflammation, scarring, and organ dysfunction. This review highlights the opinion of experts gathered for the Mexican Digestive Disease Week (2001) to analyze these molecular events with emphasis on identifying possible therapeutic opportunities. Inflammatory response encompasses leukocyte infiltration, favored by adhesion molecules of the selectin family, chemokines, integrins, and activated stellate cells (SC). Quiescent SC undergo activation mediated by mechanical stress and expression of cytokines, oxidative stress products, and growth factors and play a significant role in fibrosis and in reparation toward synthesis of extracellular matrix components. Also, hepatocytes and acinar cells contribute to the inflammatory and fibrotic response. Molecules that down-regulate this response are overexpressed. Therapeutic strategies with targeting to such mechanisms underlying chronic hepatic and pancreatic injury are an emerging reality.

Fibrosis↗
PubMedDate not supplied

Health-related quality of life and depression in patients with chronic hepatitis C.

BACKGROUND: Hepatitis C is a major cause of liver disease worldwide. It has been associated with decreased health-related quality of life (HRQL) and psychiatric symptoms. Our aim was to assess HRQL, depression, and illness understanding in patients with chronic hepatitis C without previous interferon therapy. METHODS: Consecutive patients attending a referral center were enrolled. HRQL was measured using SF-36 questionnaire, depression with Zung self-rating depression scale, and illness understanding with self-applied knowledge test. RESULTS: Of 157 patients enrolled, 112 were female (71%) and 45 male (29%). Ninety-seven patients (61.8%) had cirrhosis. HRQL was significantly decreased in chronic hepatitis C patients compared to historical normal controls in all eight domains of the SF-36 (p < 0.001). In hepatitis C cirrhotic patients, HRQL was significantly lower among Child-Pugh class B and C subjects in domains reflecting physical health (p <0.05). Ninety-two patients (58.6%) had depression that resulted in lower HRQL when compared to nondepressed patients (p <0.05). One hundred fourteen patients (72.6%) had poor illness understanding of hepatitis C. These subjects had significantly lower HRQL scores in six of eight SF-36 domains when compared to patients with better understanding of the disease (p <0.05). CONCLUSIONS: Chronic hepatitis C patients attending a tertiary-referral center had significant decrease in HRQL associated with depression (58.6%) and poor illness understanding (72.6%). Educational programs and their impact on HRQL need to be addressed in detail, particularly for the pre-treatment scenario.

Attitude to Health↗
PubMedDate not supplied

Early HCV RNA changes in patients with chronic hepatitis C treated with peginterferon alfa 2b and ribavirin.

INTRODUCTION: Currently, interferon alfa and ribavirin are the mainstay of therapy for patients with chronic hepatitis C. Recently the pegylation of interferon has allowed a once weekly application, resulting in an increased sustained viral response rate. The analysis of serum HCV dynamics has been shown to be useful in predicting clinical effects and optimizing the treatment regimen. AIM: The aim of the present study was to assess early serum HCV RNA changes in patients with chronic hepatitis C treated with peginterferon alfa 2b plus ribavirin. METHODS: Male and female patients aged 18 to 65 years with chronic hepatitis C were eligible for the study. All patients received peginterferon alfa 2b 1.5 micrograms/kg once-weekly for 4 weeks and then peginterferon alfa 2b 0.5 microgram/kg once-weekly until the completion of the 48 week trial period, plus ribavirin orally with meals, adjusted to body weight. HCV RNA was determined at base-line, 48 hours, 4 and 12 weeks of therapy. RESULTS: Data were obtained from 20 patients with chronic hepatitis C treated with peginterferon alfa 2b and ribavirin; 16 male, 4 female, with a mean age of 44.4 +/- 11.9 years, 16 patients (80%) were infected with HCV genotype 1, the remainder were infected with genotype 2. Mean baseline HCV RNA for the total group was 1,091,405 +/- 972,715 IU/mL. Mean reductions in viral load at 48 hours, 4 and 12 weeks for the 20 patients were 1.31 +/- 0.91 log, 1.99 +/- 1.27 log and 2.31 +/- 1.25 log, respectively. A > 2 log reduction in HCV RNA was noticed in 12/20 patients (60%) at 4 weeks (early viral responders), in 9 of them (45%) HCV RNA was undetectable. This response in HCV RNA persisted at 12 weeks of therapy. Early viral responders had a significant reduction in HCV RNA at 48 hours after the initial peginterferon alfa 2b injection (> 1 log reduction). Early viral response was observed in 8/16 patients with HCV genotype 1, and in all genotype 2 patients. CONCLUSION: Treatment with peginterferon alfa 2b and ribavirin produces significant changes in the early HCV viral dynamics supporting the concept that such changes may be pivotal in achieving a sustained viral response.

Adolescent↗
PubMedDate not supplied

Amebic liver abscess.

Amebic liver abscess (ALA) highly endemic in most developing tropical countries is being encountered more frequently in other geographical areas maybe secondary to increased travel to areas where the disease is endemic as well as in the homosexual population. We report a classical clinical case of ALA in a 44 years old man diagnosed by ultrasound and positive seroameba titers who responded to oral imidazoles.

Administration, Oral↗
PubMedDate not supplied

[Comparison of two different vaccination schemes against Hepatitis A and B in Mexican children and adolescents].

BACKGROUND: Development of multiple antigens in combined vaccines offers the advantages of reducing costs, increasing compliance and provides dual protection. Hepatitis A is an endemic disease in Mexico and hepatitis B, notwithstanding low prevalence, confers risk of progression to cirrhosis, hepatocellular carcinoma, and high medical costs in consequence. OBJECTIVE: Determine immunogenicity and reactogenicity of a combined vaccine when compared with use of conventional vaccines simultaneously. METHODS: The present study was a prospective, open, and randomized trial; 73 healthy children and adolescents were included, all with negative serologic markers. They were assigned to one of the following groups: Group 1, combined vaccine (n = 49) Twinrix (HAV 720 UE/HBV 20 micrograms), and group 2, separate vaccines (n = 24) Engerix B 20 micrograms/Havrix 720 UE. Both groups were given two-dose series at months 0 and 6. Geometric titles of antibody production (GMT) anti-HAV and anti-HBV were determined in months 1, 2, 6 and 7. Adverse reactions were registered during the study. RESULTS: No difference was observed between the two groups in age or gender. Immunogenicity anti-HAV: 100% of vaccines in both groups reached seroprotective levels (> or = 33 mUI/mL). Antibody titles in group 1 were three times higher than those in group 2 (9,696 mIU/mL vs. 3,940 mIU/mL [p = 0.003]) at the end of the study. Immunogenicity anti-HBV: All subjects in both groups reached seroprotective levels (> or = 10 mIU/mL) with similar antibody titles at the end of the study (group 1: 5,603 mIU/mL vs. group 2: 5,201 mIU/mL [p = 0.55 NS]). Reactogenicity: No serious adverse reactions were observed; main were local, and frequency and characteristics were similar in both groups. CONCLUSIONS: Seroprotective levels and reactogenicity obtained from use of a combined vaccine against hepatitis A/B are acceptable when compared with use of conventional vaccines administered separately.

Adolescent↗