Search PubMed⌕ Search

Biomedical subjects

S W French

Publications and source records attributed to S W French.

At least 91 records · Page 5Linked to original sources
PubMed1993

Expression of the beta 1 chain (CD29) of integrins and CD45 in alcoholic liver disease. The VA Cooperative Study Group No. 275.

OBJECTIVES: In the active stages of alcoholic liver disease (ALD), we have shown previously an enhanced expression of either CD4 or CD8 molecules on CD3+T cells. Class I and II MHC molecules expression were enhanced on lymphocytes, and on the cell membrane of hepatocytes, thus suggesting that an intrahepatic antigen-dependent lymphocyte-hepatocyte interaction occurs. Here we report the pattern of expression of several additional molecules known to participate in nonspecific cell-cell adhesion preceding alloantigen recognition i.e., the beta 1 chain of integrins (CD29) and the isoforms of the leukocyte common antigen CD45RA and CD45RO. METHODS: Frozen liver samples from 38 patients with advanced ALD were examined immunohistochemically by the avidin-biotin-peroxidase complex method using monoclonal antibodies. Nine patients with alcoholic fatty liver and six patients with only hepatitis C infection were included as controls and studied in a similar manner. RESULTS: CD29 was strongly expressed on the cell membrane of hepatocytes in 18/20 patients with cirrhosis, in 17/18 with alcoholic hepatitis without cirrhosis, in 5/9 of fatty liver and in all six with hepatitis C. CD45RA was present in 5/18 cases of alcoholic hepatitis and in 3/20 cases of cirrhosis on the hepatocytes plasma membrane, in none of the controls, and rarely on lymphocytes. CD45RO was expressed on the surface of lymphocytes in 14/18 cases of alcoholic hepatitis, 13/20 patients with cirrhosis, in 5/9 of fatty liver and in one with hepatitis C. The CD45RO lymphocytes were predominantly CD8 positive. CONCLUSIONS: Our results indicate that in ALD the hepatocytes exhibit on their plasma membrane an enhanced expression of the beta 1 chain of the integrins and less commonly CD45RA. Furthermore, the expression of only CD45RO on the surface of lymphocytes favors the postulate that the intrahepatic lymphocytes in ALD are most likely of the "memory" type. The results of this study lend further support to the contention that a cell-cell contact precedes a cell-mediated mechanism in the pathogenesis of ALD.

Antigens, CD↗
PubMed1993

Nutrition in the pathogenesis of alcoholic liver disease.

The data and experimental results reviewed here allow the construction of the following hypothesis: alcohol-induced liver disease results from a combination of two phenomena. The first is the induction of the maximum activity of CYP 2E1 by several dietary factors, i.e. (1) low carbohydrate-high fat diet; and (2) the dietary fats composed of PUFA (Yang et al., 1992). The second is the production of lipid peroxidation induced by CYP 2E1 oxidation of ethanol maintained at high blood alcohol levels (> 200 mg %) with the availability of PUFA as substrate (Ekstrom and Ingelman-Sundberg, 1988; Koop, 1992). Thus, lipid peroxidation may be the final common pathway which supports the induction of ALD. Further, it may provide the common denominator which links ALD pathogenesis to non-alcoholic steato-hepatitis (NASH) (French et al., 1989b), where CYP 2E1 is induced by high fat diet and/or diabetes (Dong et al., 1988).

Alcohol Drinking↗
PubMed1992

Cytokeratin of apparent high molecular weight in livers from griseofulvin-fed mice.

Livers from mice fed griseofulvin (GF) for 12 months contain abnormal cytokeratin (CK) intermediate filaments (IFs) that aggregate to form Mallory bodies (MBs). Sections from control and GF-treated livers were extracted with Triton X-100. IF-enriched fractions were analyzed by gel electrophoresis and IF proteins were identified by Western blotting using anti-CK 55 (TROMA 1) and CK 49 (TROMA 2), and the anti-'universal' IF known as aIF. Western blotting on control and GF-treated livers with TROMA 1 and TROMA 2 obtained with gels loaded with 2 micrograms of protein revealed the presence of CK 55 and CK 49. In contrast, when a larger amount of protein was loaded on the gel (10 or 12 micrograms) the results were different. In the control we detected bands corresponding to CK 55 and CK 49 plus a faint band at approx. 97 kDa. In the GF-treated animals, we detected a more pronounced reaction with the 97 kDa band and in addition we now detected several higher molecular weight bands which reacted with anti-CK antibodies. These results demonstrated that the induced changes in CKs in the GF liver are associated with the increase of apparent high molecular weight CK. These apparent high molecular weight CKs could be obtained by a pathological cross-linking of the preexisting liver CK monomers in different combinations such as CK 55-55, CK 49-49 and/or with other proteins.

Animals↗
PubMed1992

Differential phosphorylation of CK8 and CK18 by 12-O-tetradecanoyl-phorbol-13-acetate in primary cultures of mouse hepatocytes.

The phosphorylation of cytokeratin was investigated in primary cultures of hepatocytes. The two hepatocyte cytokeratins CK8 and CK18 (55,000 and 49,000 M(r) respectively) were phosphorylated, CK8 being more phosphorylated than CK18. Treatment of the hepatocytes with 150 nM 12-O-tetradecanoyl-phorbol-13-acetate (TPA) an activator of protein kinase C induced a transient increase in the level of phosphorylation of CK8 but not CK18. This effect was maximal after 15 min of TPA treatment and was maintained for up to 3 h. After 22 h of treatment with TPA, which down-regulates protein kinase C, CK8 phosphorylation was returned to the basal level. Further addition of TPA to the 22-h treated cells did not cause an increase in CK8 phosphorylation. Indirect immunofluorescence microscopy with a monoclonal antibody to CK8 indicated that while the addition of TPA induced the formation of granular cytokeratin aggregates in some hepatocytes, in most hepatocytes no major changes in the intermediate filament network were observed. Staining for actin showed that actin microfilaments were rapidly reorganized after the treatment and a loss of stress fibres were observed. We propose that CK8 is an in vivo substrate for protein kinase C and that the specific phosphorylation of CK8 plays a role in protein kinase C signal transduction.

Animals↗
PubMed1992

Effects of dietary fat composition on activities of the microsomal ethanol oxidizing system and ethanol-inducible cytochrome P450 (CYP2E1) in the liver of rats chronically fed ethanol.

We studied the effects of dietary fat composition on the activities of the microsomal ethanol oxidizing system (MEOS), paranitrophenol hydroxylase (PH) activity and ethanol-inducible cytochrome P450 isozymes (CYP2E1 and CYP2B1) in the liver of rats to determine the role of this ethanol metabolizing pathway in the pathogenesis of alcoholic liver disease (ALD). Wistar male rats were pair-fed a liquid diet, containing either tallow (TF) or corn oil (CF) as the fat component, and ethanol or an isocaloric amount of dextrose, through an implanted intragastric cannula. Liver pathology of rats fed ethanol (CF-ALC) and CF diet showed severe fatty change whereas the rats fed TF-alcohol and the TF and CF controls did not. MEOS activity of the CF-ALC group was 8 times of that in the CF-CTL group (P less than 0.01). In TF-ALC rats, MEOS activity was increased to 2.6 times compared to that of TF-CTL (P less than 0.01). ApoCYP2E1 in CF-ALC and TF-ALC were 818 +/- 63 and 433 +/- 1- pmol/mg protein, respectively, and these values were significantly higher when compared with those of the pair-fed controls (P less than 0.005). In contrast, apoCYP2B1 was increased to an equal degree in both CF-ALC and TF-ALC. When PH-activity was measured, the level of activity on TF-ALC rats did not differ from that of CF-ALC rats. Thus, ethanol-induction of apoCYP2B1 (2x) and PH (6-8x) were the same for CF and TF (2x); but not for apoCYP2E1 (21 and 8x, respectively) and MEOS activity (8 and 2.6x, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Oxidoreductases↗
PubMed1992

Biochemistry of alcoholic liver disease.

The biochemistry of alcohol liver disease as it relates to clinical medicine and experimental alcohol liver disease is presented. Clinical features are emphasized in the diagnosis of alcohol liver disease, particularly as it relates to staging the disease and predictors of prognosis. Currently, it is true that the biochemical diagnosis of alcohol liver disease is at best very limited in terms of the sensitivity tests and specificity of the test. It is particularly difficult to detect alcohol liver disease biochemically in the early stages when steatohepatitis is not severe. Consequently, 50% of the patients have already developed cirrhosis at the time they are diagnosed clinically. In this review indicators of malnutrition are emphasized because they have the strongest implications regarding survival during the acute hospitalization stage of the disease. They are also the best indicators of response to therapy during the recovery phase. With respect to experimental work on the pathogenesis of alcohol liver disease, it appears that necrosis is due to the inability to increase blood flow to compensate for increased oxygen utilization. The hypothesis that mitochondrial damage is the cause of liver cell damage is regarded as less important in the pathogenesis of necrosis. The shift in the redox state during alcohol metabolism accounts for the fatty change noted in the central lobular area of the liver in animals fed alcohol. Apparently, there is strong experimental evidence that highly reactive intermediates are important in the pathogenesis of liver damage due to the induction of the isozyme cytochrome P450 IIE1 by alcohol ingestion. This mechanism is enhanced by a diet high in polyunsaturated fatty acids.

Animals↗
PubMed1991

Distinctive infrared spectral features in liver tumor tissues of mice: evidence of structural modifications at the molecular level.

Mice were treated with griseofulvin (GF) containing diet or control diet for 12 months. The livers from mice fed griseofulvin showed large tumors that were excised and used for analysis. The infrared spectra from control liver tissue and tumor tissue from GF livers were measured and compared as a function of pressure up to 27 kbar. Many changes in the infrared spectral features of the tumor tissue were observed. Results showed that neoplasm formation involved structural modifications of nucleic acids, lipids, carbohydrates, and proteins in the liver cells, which were detected from the abnormal vibrations of the functional groups in these biomolecules. The amount of glycogen was dramatically decreased in the tumor tissue compared to the control tissue. Important changes in the strength of hydrogen-bondings in the phosphodiester backbone of the nucleic acids and in the C-O groups of tissue proteins and carbohydrates were observed. Stronger interchain interactions and thus close interchain packing among the lipids in the GF liver were evident. These results showed very close similarities with those obtained with other types of tumors such as human colon cancer, suggesting that a common pattern of molecular changes has been identified in neoplastic transformation.

Amides↗
PubMed1991

Alteration in molecular structure of cytoskeleton proteins in griseofulvin-treated mouse liver: a pressure tuning infrared spectroscopy study.

Different liver diseases are associated with modifications in hepatocyte cytoskeletal organization and formation of Mallory bodies (MBs). Since the structure of a protein is critical for its function, we studied the changes in the molecular structure of the cytoskeletal protein in the liver from mice fed griseofulvin (GF), which is a good animal model for studying liver disease. Using pressure-tuning infrared spectroscopy we compared the infrared spectra of the cytoskeletal proteins from control liver and griseofulvin treated liver. The results show that the overall structure of the cytoskeletal protein was modified by the griseofulvin treatment. A relative increase in the amount of alpha-helices to beta-sheets was observed in the liver cytoskeleton from the GF-treated mice. Moreover, the random coil and the turn segments were dramatically decreased compared to controls. Pressure-induced modifications including denaturation were irreversible in the control samples whereas they were reversible in the griseofulvin-treated samples. These changes reflect important fundamental modifications in the molecular structure of the cytoskeletal proteins in the griseofulvin-treated hepatocytes. We suggest that these changes are related to the modification of the organization of intermediate filaments and the formation of MBs that occur in the GF-treated liver.

Animals↗
PubMed1991

Antibodies to hepatitis B virus and hepatitis C virus in alcoholic hepatitis and cirrhosis: their prevalence and clinical relevance. The VA Cooperative Study Group (No. 119)

Patients with overt alcoholic liver disease who had participated in a multicenter therapeutic trial and subgroups of controls (i.e., alcoholic patients without liver disease and patients with neither alcoholism nor liver disease) were tested for hepatitis B virus and hepatitis C virus antibodies to determine the prevalence of these antibodies to determine the prevalence of these antibodies and any clinical association in the progression and outcome of alcoholic liver disease. Antibodies to hepatitis B (anti-HBs and/or anti-HBc) were found in 29.2% of patients with alcoholic liver disease, in 26.1% of hospitalized alcoholic patients without liver disease and in 24.2% of hospitalized nonalcoholic patients without liver disease; frequencies were not significantly different from one another. HBsAg was not evaluated because HBsAg+ patients had been excluded from the original trial. The presence of these antibody markers correlated with ethnic origin of and immunoglobulin levels in the patients. In contrast, antibody to hepatitis C, as detected by enzyme immunoassay, was positive in 27.1%, 4.8% and 3.0% of the three groups, respectively, the first differing significantly from the other two. Antibody to hepatitis C virus positivity correlated significantly with clinical severity of the disease and with the presence of histological features that imply chronic viral infection (periportal inflammation, cirrhosis), despite the fact that the supplementary assay for antibody to hepatitis C virus, using recombinant immunoblot assay, reduced the positive rate by 79%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Alpha-fetoprotein alterations in alcoholics with liver disease. V.A. Cooperative Study Groups.

Sera on 409 male alcoholics with liver injury were assayed for alpha-fetoprotein (AFP) as part of a VA co-operative study on the natural history and therapy of alcoholic liver disease. In 78% of the patients values below normal were observed and 42% had undetectable levels. Clinically the lowest AFP concentrations were observed in the more severely ill patients with the poorest 1 year survival. Furthermore, improvement in AFP was associated with improved survival. Correlation analysis showed a relationship of AFP to (1) visceral protein concentrations (i.e. albumin, transferrin, retinal binding protein); (2) variables related to hepatic fibrogenesis (i.e. Ito cell activity, quantitative estimates of fibrosis and Kupffer cell abnormalities); and (3) changes in immunoglobulin levels particularly IgG. These findings suggest that AFP is a good index of disease prognosis.

Alcoholism↗
PubMed1991

Alterations in hepatic lipids and proteins by chronic ethanol intake: a high-pressure Fourier transform infrared spectroscopic study on alcoholic liver disease in the rat.

Using high-pressure Fourier transform infrared (FT-IR) spectroscopy, alterations of hepatic lipids and proteins in alcoholic liver disease of the rat were examined. FT-IR spectra were obtained from the liver tissues of the rats pair-fed a nutritionally adequate liquid diet and ethanol/dextrose via an implanted intragastric tube for 6 months. The pressure on the liver samples was raised up to 10 kbar, taking FT-IR spectra at regular increments as the pressure was raised. Total lipids measured by the band derived from the stretching mode of carbonyl groups in lipid (v C = O) were increased 4 times in the liver of ethanol-fed rats (E) compared with the pair-fed control rats (C). The frequency of the C = O band of E decreased with increasing pressure, which indicated that hydrogen-bonding was present on the C = O groups of lipids in E. The intensity of the CH stretching bond of the HC = CH groups was 2.8 times higher in E than that in C, which means that there was an increase in the population of unsaturated double bonds in acyl chains of lipids in E. The conformational structure of the protein molecules was slightly changed in E. The reactivity of carboxylate side groups in proteins observed by reaction with Ba++ ions was higher in E than that in C. These infrared spectroscopic results suggest that chronic ethanol intake induces not only an increase in the amount of total lipid but also changes the composition of lipids and the conformation of protein molecules in the liver of rats.

Alcoholism↗
PubMed1991

Effect of dietary fat on Ito cell activation by chronic ethanol intake: a long-term serial morphometric study on alcohol-fed and control rats.

We studied the effects of long-term ethanol ingestion and dietary fat on Ito cell activation morphometrically in rats. Sixteen pairs of Wistar male rats were divided into two groups, one fed tallow and the other fed corn oil as the source of dietary fat. Each group of rats were pair-fed a nutritional adequate liquid diet containing either corn oil (CF) or tallow (TF) as fat as well as protein and carbohydrate. Half of each group received ethanol, the rest were pair-fed isocaloric amounts of dextrose via an implanted gastric tube for up to 5 months. Morphometric analysis of the change in fat and rough endoplasmic reticulum (RER) of Ito cells was performed on electron micrographs obtained from monthly biopsies including baseline. Ito cell activation was assessed by a decrease in the ratio of fat/RER in Ito cells. The ratio of fat/RER in Ito cells of alcoholic rats fed the CF diet (CFA) gradually decreased. The ratio was found to be lower than in the pair-fed control rats (CFC) at 5 months of feeding. CFA: 1.74 +/- 0.57, vs. 7.46 +/- 2.05, respectively, p less than 0.05, mean +/- SE). Ito cell fat also significantly decreased at 5 months of feeding (p less than 0.05). The fat/RER ratio in CFA significantly decreased only subsequent to the development of fatty change, necrosis, and inflammation followed by fibrosis of the liver. In contrast, the TFA rats did not show a significant decrease in the fat/RER ratio in the Ito cells throughout the study, while TFC rats showed an increase in the fat/RER ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Ito cell activation induced by chronic ethanol feeding in the presence of different dietary fats.

Bronfenmajer et al. (1966) first studied Ito cells in alcoholic hepatitis (AH) by light microscopy (LM). The number of Ito cells and the number of fat droplets were increased. Okanoue et al. (1983) found that Ito cells were reduced by LM but increased by electron microscopy (EM) in scars in AH. Ito cells were activated in scars (increased RER and decreased fat in Ito cells with transition to fibroblasts). Minato et al. (1983) showed that increased RER in Ito cells correlated with increased collagen synthesis of liver biopsies in vitro. Mak et al. showed increased RER correlated with the degree of fibrosis in alcoholic baboons (1984) and alcoholic cirrhosis in man (1988). French et al. (1988b) showed morphometrically that Ito cell fat was decreased and RER was increased only in scars but not in normal sinusoids so that Ito cell activation was restricted to the scars. There was no correlation of sinusoidally located Ito cell fat or RER with the amount of perisinusoidal collagen. In rats fed ethanol and a nutritionally adequate diet including corn oil (25% of calories) by intragastric cannula for five months the fatty liver progressed to focal central fibrosis, and Ito cell activation (fat/RER) was increased. When tallow was substituted for corn oil the Ito cells were not activated and the liver histology was normal. Thus, the type of dietary fat and the local environment (scars) are important factors in the activation of Ito cells by alcohol in vivo.

Alcoholism↗
PubMed1991

The mechanism of organ injury in alcoholics: implications for therapy.

Organ damage due to alcohol abuse includes especially the CNS and the GI tract. The mechanism of liver injury has been studied in depth. Alterations in membrane fluidity, signal transduction, cytochrome, P-450 induction, oxidative stress, acetaldehyde adducts, eicosanoid metabolism, cytoskeletal function, energy metabolism, O2 consumption, microcirculation, Kupffer cell and ito cell activation, immune injury, and gene expression have been documented. Therapeutic implications of these studies include oxandrolone, PTU and colchicine. Pancreatic injury has been studied in vivo and with isolated acini. Amylase release is enhanced directly by ethanol probably by increasing cytosolic Ca2+. Chronic alcohol feeding decreases the CCK receptor sensitivity and affinity for CCK and the pkc response is reduced as is Ca2+ mobilization. Eicosanoids may mediate the damage to the gastric microcirculation. Inhibitors of leukotriene A4 synthesis reduce the ethanol-induced mucosal damage. Exogenous prostaglandins protect the gastric mucosa from ethanol damage and microvascular stasis. In the CNS, alterations induced by ethanol include changes in membrane fluidity and receptor transduction modulation.

Alcoholism↗
PubMed1991

Prognostic factors in alcoholic liver disease. VA Cooperative Study Group.

Two hundred eighty-one alcoholic patients were prospectively evaluated by clinical, biochemical, and histologic parameters during a 4-yr period to assess their prognosis. They were stratified into four categories of injury: 1) fatty liver (26 patients), 2) acute alcoholic hepatitis (106), 3) cirrhosis (39), and 4) cirrhosis with superimposed alcoholic hepatitis (111). The rate of survival and variables correlating with survival varied according to the group. At 48 months, 70% of the patients with fatty liver were alive, 58% in the alcoholic hepatitis group, 49% in cirrhosis, and 35% in alcoholic hepatitis superimposed upon cirrhosis. Within group one, deaths were due to causes unrelated to liver disease. In the alcoholic hepatitis group, factors significantly correlating with survival were ascites, alanine amino-transferase levels, grams of alcohol consumed, continuation of alcohol intake, and clinical severity of disease. Survival in patients of group three correlated significantly with prothrombin time and histologic severity score. Patients with combined cirrhosis and alcoholic hepatitis exhibited the worst prognosis, with the most significant predictors of survival being age, grams of alcohol consumed, the ratio of serum aminotransferases (AST:ALT) and the histologic and clinical severity of the disease. Although a different pattern of correlates was observed for each pathologic level of injury, knowledge of the various correlates aids in prognostic assessment.

Acute Disease↗
PubMed1990

In vivo hepatic energy metabolism during the progression of alcoholic liver disease: a noninvasive 31P nuclear magnetic resonance study in rats.

We investigated serially in vivo the ratios of phosphorylated metabolites and the intracellular pH in the livers of rats fed ethanol chronically to evaluate the relation between changes in energy metabolism and the progression of alcoholic liver disease with 31P nuclear magnetic resonance spectroscopy. 31P nuclear magnetic resonance spectra of the liver were acquired noninvasively from rats pair-fed a nutritionally adequate liquid diet containing ethanol or an isocaloric amount of dextrose with an implanted intragastric cannula for up to 24 wk. A high blood alcohol level was constantly maintained. The spectra were obtained using a surface coil combined with a ferrite screen to eliminate nuclear magnetic resonance signals derived from the superficial muscles. Contaminating 31P nuclear magnetic resonance signals arising from abdominal tissues other than the liver were eliminated from the spectra by digital subtraction. Throughout the study the inorganic phosphate/beta-ATP peak area ratio observed in alcohol-fed rats was found to be consistently elevated in comparison with the control rats (at 3 to 5 wk alcohol-fed rats = 1.20 +/- 0.10, control rats = 0.78 +/- 0.04, p less than 0.05.; at 22 to 24 wk alcohol-fed rats = 1.23 +/- 0.10, control rats = 0.81 +/- 0.06, p less than 0.05.; mean +/- S.E.). The phosphomonoesters/beta-ATP ratio tended to be higher in alcohol-fed rats when compared with control rats. The intracellular pH measured by the chemical shift of the inorganic phosphate peak showed no significant differences between alcohol-fed rats and control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1990

Role of cytokeratin intermediate filaments in transhepatic transport and canalicular secretion.

The role of cytokeratin filaments in the function of hepatocytes was investigated using a nickel-treated hepatocyte in vitro model. Cytokeratin intermediate filaments were selectively dissociated from the cell cortex by nickel treatment. Cytokeratins and ubiquitin were observed using immunofluorescence and immunoelectron microscopy. Hepatocytic function was assessed by visualizing uptake, transhepatic transport and secretion of fluorescein diacetate and horseradish peroxidase into the bile canaliculi. In control primary cultures, most of the bile canaliculi were surrounded by an inner layer of actin filaments and an outer pericanalicular sheath of cytokeratin filaments and microtubules. The cytoplasmic distribution of ubiquitin was diffuse and particulate. After treatment with NiCl2 (150 micrograms/ml) for 24 hr, the cytokeratin filaments and desmoplakin became focally detached from the cell cortex and retracted to form an aggregate around the nucleus. These aggregates were associated with intense ubiquitin immunoreactivity. Only a few attachments of the cytokeratin filaments to the cell cortex remained. F-actin remained attached to the cell cortex in the areas where the cytokeratin filaments had become detached. The pericanalicular sheath of cytokeratin filaments and the bile canaliculi disappeared and actin was dispersed over the entire cell periphery. Fluorescein diacetate secretion and horseradish peroxidase uptake were almost completely absent in the hepatocytes treated with nickel. The effects of nickel persisted 24 hr after its removal from the medium. It is concluded that cytokeratin intermediate filaments play a critical role in the formation of the bile canaliculus, secretion of fluorescein diacetate and uptake of horseradish peroxidase. Further, our study indicates that cytokeratin ubiquitination occurs during collapse and aggregation of the cytokeratin filaments. The formation of cytokeratin-ubiquitin conjugates during aggregation suggests a role of ubiquitin in the control of cytokeratin organization in hepatocytes in the response to cell stress.

Animals↗