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Biomedical subjects

D Kershenobich

Publications and source records attributed to D Kershenobich.

At least 19 recordsLinked to original sources
PubMed2002

Pentoxifylline diminished acetaldehyde-induced collagen production in hepatic stellate cells by decreasing interleukin-6 expression.

The effect of pentoxifylline (PTX), a methylxanthine derivative, on collagen induction and secretion and on the production of mRNA of two fibrogenic cytokines: interleukin-6 and transforming growth factor-beta(1) (IL-6 and TGF-beta(1)) in a rat hepatic stellate cell line (CFSC-2G) exposed to acetaldehyde was studied. CFSC-2G cells were treated with 175 microM acetaldehyde for 24h. The cells were then exposed to a medium containing 200 microM PTX. Collagen secretion, increased 2.6 times in acetaldehyde treated cells. Cells exposed to acetaldehyde and treated with PTX diminished collagen secretion to control values and decreased alpha(1)(I) collagen mRNA by 15%. Reverse transcriptase-polymerase chain reaction (RT-PCR) assays of TGF-beta(1) mRNA showed no variation in different experimental conditions. However, PTX induced a decrease of 32% in IL-6 mRNA in acetaldehyde-treated cells. CFSC-2G cells treated with anti-IL-6 monoclonal antibody, 15min before acetaldehyde was added, did not present an increase in alpha(1)(I) collagen mRNA. These results show that PTX inhibits the expression of alpha(1)(I) collagen via the inhibition of IL-6 in acetaldehyde treated cells. The effect herein reported on IL-6 and alpha(1)(I) collagen mRNA adds to the previously described effect of PTX, which could be useful in the fibrogenic process induced by acetaldehyde.

Acetaldehyde↗
PubMed2001

Expression of urokinase-type plasminogen activator in an experimental model of hepatocarcinoma.

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver. Molecular genetic analyses have clarified that accumulation of genome changes provides important steps in carcinogenesis. Urokinase type plasminogen activator (uPA) forms part of an important enzymatic system that degraded the extracellular matrix in process of invasion and metastasis. In order to study the kinetics of uPA cellular expression during this process, we used specific polyclonal antibodies against uPA in an immunohistochemistry assay in liver sections from a HCC in rats. The neoplastic transformation induced with this model was preceded by the appearance of numerous hyperplastic nodules during early stages, after time lesions progressed to well-differentiated HCC. The morphological changes of premalignant and malignant lesions were associated with a progressive increment of uPA expression, which reached its peak at 5 and 6 months after the administration of the carcinogenic drugs. Of the enzymatic markers analyzed, the gamma glutamyl transpeptidase showed correlationship with the histological findings. Our results suggest that the increase in the uPA expression should not only be considered as the hallmark of metastasis, but may also be related to early events in the neoplastic transformation and with the proliferation of vessels and biliary ducts.

Animals↗
PubMed2001

Metadoxine prevents damage produced by ethanol and acetaldehyde in hepatocyte and hepatic stellate cells in culture.

Metadoxine (pyridoxine-pyrrolidone carboxylate) has been reported to improve liver function tests in alcoholic patients. In the present work we have investigated the effect of metadoxine on some parameters of cellular damage in hepatocytes and hepatic stellate cells in culture treated with ethanol and acetaldehyde. HepG2 and CFSC-2G cells were treated with 50 mM ethanol or 175 microM acetaldehyde as initial concentration in the presence or absence of 10 microg ml(-1) of metadoxine. Twenty-four hours later reduced and oxidized glutathione content, lipid peroxidation damage, collagen secretion and IL-6, IL-8 and TNF- alpha secretion were determined. Our results suggest that metadoxine prevents glutathione depletion and the increase in lipid peroxidation damage caused by ethanol and acetaldehyde in HepG2 cells. In hepatic stellate cells, metadoxine prevents the increase in collagen and attenuated TNF- alpha secretion caused by acetaldehyde. Thus, metadoxine could be useful in preventing the damage produced in early stages of alcoholic liver disease as it prevents the redox imbalance of the hepatocytes and prevents TNF- alpha induction, one of the earliest events in hepatic damage.

Acetaldehyde↗
PubMed2001

Effect of endotoxin pretreatment on hepatic stellate cell response to ethanol and acetaldehyde.

BACKGROUND AND AIM: The role of endotoxin in alcohol-induced liver damage is well recognized. How pre-exposure to endotoxin might affect alcohol injury is not known. We herein studied the effect of endotoxin pretreatment on hepatic stellate cell (HSC) response to ethanol and acetaldehyde. METHODS: Rat HSC (CFSC-2G) were exposed to media supplemented with 1 microg/mL lipopolysaccharide (LPS). This was followed by a 24 h exposure to media containing LPS plus 50 mmol/L ethanol or 175 micromol/L acetaldehyde. Lipid peroxidation, collagen, and tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and transforming growth factor (TGF)-beta1 secretion were determined at the end of both periods of exposure. RESULTS: Lipopolysaccharide pretreatment did not modify lipid peroxidation induced by ethanol or acetaldehyde alone. Glutathione (GSH) content decreased to 4.2 +/- 0.5 and 16.3 +/- 0.8 nmol protein after exposure to ethanol or acetaldehyde alone, and decreased further with LPS pretreatment (2.4 +/- 0.2 and 2.7 +/- 0.3 nmol/mg protein, respectively). Oxidized GSH (GSSG) content increased in ethanol and acetaldehyde LPS-pretreated cells only. Collagen secretion increased to 988 +/- 82 and 1169 +/- 91 microg/10(6) cells after exposure to acetaldehyde or LPS alone. Lipopolysaccharide pretreatment enhanced collagen secretion significantly in both ethanol- and acetaldehyde-treated cells (969 +/- 56 and 1360 +/- 72 microg/10(6) cells, respectively). Interleukin-6 production increased to 288 +/- 48, 1195 +/- 86 and 247 +/- 35 pg/mL per 10(6) cells after ethanol, acetaldehyde and LPS exposure, and increased further with LPS pretreatment in ethanol-exposed cells (680 +/- 23 pg/mL 10(6) cells). CONCLUSION: Lipopolysaccharide pretreatment of HSC adds to the damage produced by ethanol and acetaldehyde by diminishing GSH content and increasing GSSG content, collagen and IL-6 secretion.

Acetaldehyde↗
PubMed2001

Cytokine response and oxidative stress produced by ethanol, acetaldehyde and endotoxin treatment in HepG2 cells.

BACKGROUND: Inflammatory mediators, including cytokines and reactive oxygen species, are associated with the pathology of chronic liver disease. Hepatocytes are generally considered as targets but not producers of these important mediators. OBJECTIVES: To investigate whether cells of hepatocellular lineage are a potential source of various cytokines we estimated the expression and secretion of tumor necrosis factor alpha, transforming growth factor beta 1, and interleukins 1 beta, 6 and 8 in the culture of well-differentiated human HepG2 cells treated for 24 hours with ethanol, acetaldehyde and lipopolysaccharide. Lipid peroxidation damage, glutathione content and glutathione peroxidase, catalase and superoxide dismutase activity were also determined. METHODS: HepG2 cells were treated for 24 hours with ethanol (50 mM), acetaldehyde (175 microM) and LPS (1 microgram/ml). TNF-alpha, TGF-beta, IL-1 beta, IL-6 and IL-8 mRNA were determined by reverse transcriptase polymerase chain reaction and secretion by enzyme-linked immunoassay. Lipid peroxidation damage, glutathione content and antioxidant enzyme activities were determined spectrophotometrically. RESULTS: Exposure to ethanol for 24 hours induced the expression of TNF-alpha and TGF-beta 1, secretion of IL-1 beta and TGF-beta 1 and decreased catalase activity. Acetaldehyde markedly increased TNF-alpha and IL-8 expression, stimulated IL-1 beta and IL-8 secretion, increased lipid peroxidation damage and decreased catalase activity, while LPS exposure induced the expression of TNF-alpha, TGF-beta 1, IL-6 and IL-8, the secretion of TGF-beta 1, IL-1 beta, IL-6 and IL-8, and a decrease in catalase activity. No change in GSH, GSHPx or SOD was found in any experimental condition. CONCLUSIONS: The present studies confirm and extend the notion that hepatocytes respond to ethanol, acetaldehyde and LPS-producing cytokines. Oxidative stress produced by the toxic injury plays an important role in this response through up-regulation of inflammatory cytokines.

Acetaldehyde↗
PubMed2001

Viral dynamics in hepatitis C.

The hepatitis C virus is an enveloped positive-sense single-stranded RNA virus, which has been classified into 6 major genotypes and over 100 subtypes. HCV replicates mainly in the hepatocyte. Recently, infectious HCV cDNA clones have been generated. Despite evidence that innate and adaptative humoral and cellular immune responses are activated as part of an antiviral defense, HCV has a remarkable ability to establish persistent infection. The analysis of viral kinetics using mathematical modeling shows a relative steady state without treatment, while an immediate biphasic HCV decline occurs in blood during successful treatment, the latter being predictive of clearance of HCV by the end of treatment.

Hepacivirus↗
PubMed1999

Cytokines, growth factors, and oxidative stress in HepG2 cells treated with ethanol, acetaldehyde, and LPS.

Inflammatory mediators, including cytokines, growth factors, and reactive oxygen species, are associated with the pathology of chronic liver disease. In the liver, cytokine and growth factor secretion are usually associated with nonparenchymal cells, particularly Kupffer cells. In the present studies, the effect of 24 and 72 h administration of ethanol (50 mM). acetaldehyde (175 microM), and LPS (1 microg/ml) were studied on the expression and secretion of TNF-alpha, IL-1beta, IL-6, and TGF-beta3, lipid peroxidation damage and glutathion content in HepG2 cell cultures. A 24 h exposure to ethanol induced the expression of TNF-alpha and TGF-beta1, and the secretion of IL-1beta and TGF-beta1. With the same period of treatment, acetaldehyde markedly increased TNF-alpha expression, and stimulated IL-1beta secretion, while LPS exposure induced the expression of TNF-alpha, IL-6, and TGF-beta1, and the secretion of IL-1beta, IL-6, and TGF-beta1. A reduced in TNF-alpha response and TGF-beta1 expression were observed after 72 h exposure to ethanol. A 72 h acetaldehyde exposure decreased markedly TNF-alpha expression and stimulated a previously absent TGF-beta1 response. With the same time of exposure, LPS reduced slightly TGF-beta1 expression, and decreased its secretion. IL-1beta and IL-6 were not detected under 72 h exposure conditions. Lipid peroxidation damage was increased in all treatments, but higher values were found in 72 h treatments. Glutathion content diminished in all treatments. These findings suggest that HepG2 cells, independent of other cells such as Kupffer or macrophages, participate in a differential cytokine, growth factor and oxidative stress response, which differs according to the toxic agent and the time of exposure.

Acetaldehyde↗
PubMed1999

Pyogenic Liver Abscess.

The percutaneous approach-specifically, ultrasound-guided percutaneous catheter drainage-associated with intravenous administration of antibiotics is the therapy of choice in patients with single or multiple pyogenic liver abscesses. The initial empiric antibiotic therapy should be modified based on results of blood and pus cultures. Surgery should be reserved for patients in whom antibiotic therapy and percutaneous drainage is unsuccessful.

Journal Article↗
PubMed1998

MHC class II sequences of susceptibility and protection in Mexicans with autoimmune hepatitis.

BACKGROUND/AIMS: Autoimmune hepatitis has a genetic background associated with different HLA DRB1 alleles depending on the ethnic group. The aim of this study was to analyse the immunogenetics of type I autoimmune hepatitis in Mexicans. METHODS: Thirty Mexican Mestizo patients and 175 healthy controls were HLA typed as follows: class I antigens were determined by microlymphocytotoxicity and class II typing was done on DNA samples using PCR-SSO and PCR-SSP for DRB1, DQA1 and DQB1 loci. RESULTS: A significant association of autoimmune hepatitis with DRB1*0404 was found, (chi2Y=19.95, pc=0.002, RR=7.71), suggesting the presence of a susceptibility gene located at the DRB1 locus. Resistance was at least partially due to a DQB1 gene, since a significant decrease in DQB1*0301 was also detected (chi2Y=8.21, pc=0.04). Analysis of subgroups according to age at onset showed an association with DRB1*0404 (chi2Y=4.31, p=0.04) in patients with late onset (after 30 years), while DQA1*0501 (chi2Y=5.12, p=0.02) was increased in the early onset group. CONCLUSIONS: The possible mechanism of HLA association is due to "shared epitopes", since DRB1*0404, and those found in other populations namely, DRB1*0401, *0405 and *0301 share almost the same sequence at position 67-72 (LLEQRR, R or K at 71). Valine-86 is also relevant to the age at onset because DRB1*0404 is increased in the patients with an average age at onset of 32. These findings are relevant in determining which peptides in the liver are targets for T cells.

Adult↗
PubMed1997

Helicobacter pylori infection among patients with alcoholic and nonalcoholic cirrhosis.

BACKGROUND: The prevalence of Helicobacter pylori in patients with alcoholic and nonalcoholic cirrhosis is uncertain. The present study was aimed at determining the prevalence of H. pylori infection among cirrhotic patients and to explore its relationship to demography, etiology of cirrhosis, and liver function. MATERIALS AND METHODS: Thirty-three cirrhotic patients were included. H. pylori infection was determined by the 14C urea breath test (n = 30) and endoscopy with antral biopsy (n = 4). Etiology of cirrhosis was classified as alcoholic or nonalcoholic. The rate of H. pylori infection was related to age, gender, etiology, Child-Pugh grading, portal hypertension, and portal-systemic encephalopathy (PSE). None of the patients received antibiotics for at least the last 3 months. RESULTS: Twelve alcoholic and 21 nonalcoholic cirrhotics, with a median age of 57 years and a male:female ratio of 1:1.4 were studied. Overall H. pylori prevalence was 45.5%. This prevalence varied from 47.1% to 43.8% in those younger and older than the median age, and from 35.7% to 52.6% in men and women, respectively. Fifty percent of alcoholic and 42.9% of nonalcoholic cirrhotics were H. pylori-positive. According to Child-Pugh grading, 69% of grade A, 40% of grade B, and 0% of grade C were infected (p = .03). Among patients with PSE, 25% were H. pylori-positive compared to 52% of those without PSE (p = .24). CONCLUSIONS: The prevalence of H. pylori infection in cirrhotics is 45.5%. Prevalence was unrelated to age, gender, and etiology of cirrhosis. An inverse relation to the Child-Pugh grading and a tendency to a lower prevalence in PSE was found.

Adult↗
PubMed1996

Epitope mapping and reactivity of autoantibodies to the E2 component of 2-oxoglutarate dehydrogenase complex in primary biliary cirrhosis using recombinant 2-oxoglutarate dehydrogenase complex.

Five different target mitochondrial autoantigens recognized by sera from patients with primary biliary cirrhosis (PBC) have been identified as subunits of the following 2-oxo acid dehydrogenase complexes: the pyruvate dehydrogenase complex (PDC), the branched chain 2-oxo acid dehydrogenase complex (BCOADC), and the 2-oxoglutarate dehydrogenase complex (OGDC). Unlike the E2 subunits of PDC (PDC-E2) and BCOADC (BCOADC-E2), the E2 subunits of OGDC (OGDC-E2) reactivity of PBC sera and the reactive epitope of OGDC-D2 have not hitherto been studied in detail. In this report, we took advantage of a recombinant fusion protein for OGDC-E2 to address these issues. Eighty of 268 (29.9%) PBC patient sera but none of the 45 controls reacted with recombinant OGDC-E2. The recombinant OGDC-E2 was judged to express the immunodominant epitope, because when sera from patients with PBC were preabsorbed with the recombinant fusion protein, such sera were depleted of reactivity against 48 kD OGDC-E2 when probed on beef heart mitochondria (BHM) but retained reactivity toward PDC-E2 and/or BCOADC-E2. Furthermore, affinity-purified PBC sera against recombinant OGDC-E2 reacted only with native OGDC-E2 and not with any other enzyme components of the 2-oxo acid dehydrogenase complex. Antimitochondrial autoantibodies (AMA) against OGDC-E2 included immunoglobulin (Ig)G2, IgG3 and IgM and the relative titers were as follows: IgG2 > IgG3 > IgM. Finally, using overlapping recombinant polypeptides, it was determined that a minimum of 81 amino acids (residues 67-147) corresponding to the lipoyl domain of OGDC-E2 are necessary for reactivity, suggesting that a conformational autoepitope is recognized by AMA. These data suggest that each of the 2-oxo acid dehydrogenase enzymes has distinct antigenicity despite their similarities in structure and function. The availability of recombinant OGDC-E2 autoantigen will allow the design of additional studies to further our understanding of the role of mitochondrial autoantigens in the pathogenesis of PBC.

Animals↗
PubMed1995

The dopamine D2 receptor gene TaqI A1 polymorphism and alcoholism in a Mexican population.

The suggested association between the TaqI A1 allele of the dopamine D2 receptor (DRD2) gene with alcoholism was studied comparing the genotypes of 38 controls and 38 ethnic matched alcoholics, drawn from the Mexican population. The alcoholics in our sample suffered from one of the following conditions: delirium tremens, alcohol hallucinosis or uncomplicated alcohol withdrawal. Eighty-eight percent of the controls carried the A1 allele. The frequency of the DRD2 A1 allele in the Mexican sample was higher than reported in Caucasians, but similar to those described in Amerindian groups. There was not any difference in the prevalence or allele frequency between alcoholics and controls. Also, there was no significant differences when alcoholics were subtyped according to severity, age of onset, or positive family history. Alcoholics showed higher scores than controls in the neuroticism and psychoticism subscales on the Eysenck Personality Inventory. However, no relationship between personality traits and genotypes was found. Our results do not support a consistent association between the D2 receptor gene and alcoholism.

Adult↗
PubMed1992

Phase II study of the safety and efficacy of a 5-lipoxygenase inhibitor in patients with ulcerative colitis.

We examined the effects of an inhibitor of 5-lipoxygenase (A-64077) in 11 patients with mild to moderately active ulcerative colitis (UC). Treatment was a daily oral dose of 800 mg for 28 days. Physicians global rating (scale 1-50) included stool characteristics, rectal bleeding, abdominal and rectal pain, urgency, and general well being; sigmoidoscopic evaluation (scale 1-15) included mucosal vascular pattern, erythema, granularity/ulcerations, friability, and exudate. All of the patients experienced a decrease in discomfort of their disease, and the gross appearance in the sigmoidoscopy improved in eight of them, but were not accompanied by histologic improvement. No significant side effects occurred. A long-term controlled double-blind and dose-effect trial using 5-lipoxygenase inhibitors is needed which may lead to a new therapeutic approach in UC.

Administration, Oral↗
PubMed1990

Effect of colchicine on lymphocyte and monocyte function and its relation to fibroblast proliferation in primary biliary cirrhosis.

Lymphocyte and monocyte function was investigated in eight patients with primary biliary cirrhosis and in age-matched and sex-matched controls. In three of the eight cirrhotic patients, two were in the late stage of the disease (stage III) and concanavalin A-induced suppressor cell function was markedly decreased; it returned to normal levels after 1 mo of treatment consisting of 5 mg per week of orally administered colchicine. The relative percentage of T cell subsets (CD3, CD4 and CD8) and the mean percentage of the helper and the suppressor phenotype were similar in cirrhotic patients and in controls. Basal production of interleukin-1 activity by a monocyte-enriched fraction of peripheral blood mononuclear cells of cirrhotic patients was three-fold above control values: after stimulation with endotoxin, interleukin-1 values increased tenfold above basal levels in monocyte-enriched fraction of peripheral blood mononuclear cells of both normal and cirrhotic patients. Colchicine normalized the basal production of interleukin-1 and inhibited its stimulation by endotoxin by 50%. Culture supernatants of endotoxin-stimulated monocyte-enriched fraction of peripheral blood mononuclear cells increased the proliferation of cultured human skin fibroblasts by 50%. In contrast, supernatants from stimulated monocyte-enriched fraction of peripheral blood mononuclear cells obtained from colchicine-treated patients significantly inhibited fibroblast proliferation. These findings suggest that stimulated chronic inflammatory cells may play an important role in liver fibrosis. Some of the actions of colchicine could be related to its effects on lymphocyte and monocyte function.

Adult↗