摘要:

AbstractBaboons fed ethanol (50% of total calories) chronically develop ultrastructural alterations of hepatic mitochondria. To determine whether mitochondrial functions are also altered, mitochondria were isolated from nine baboons fed ethanol chronically and their pair‐fed controls. At the fatty liver stage, ADP‐stimulated respiration was depressed in ethanol‐fed baboons by 59.4% with glutamate, 43.2% with acetaldehyde, 45.1% with succinate and 51.1% with ascorbate as substrates. A similar decrease was noted in the ADP/O ratio (14 to 28%) and respiratory control ratio (20 to 44%) with all substrates. Similar alterations of mitochondrial functions were observed in baboons with more advanced stages of liver disease, namely fibrosis. These changes after ethanol treatment were associated with decreases in the enzyme activities of mitochondrial respiratory chain: glutamate, NADH and succinate dehydrogenase (42, 24 and 28%, respectively), glutamate‐, NADH‐or succinate‐cytochrome c reductase (42, 27 and 32%, respectively) and cytochrome oxidase (59.6%). The content of all cytochromes was also decreased in ethanol‐fed baboons, especially aa3(57%). Moreover, [14C] leucine incorporation into mitochondrial membranes was depressed by 21% after ethanol treatment. On the other hand, glutamate dehydrogenase activities of serum and cytosol in ethanol‐fed baboons were significantly higher than those in pair‐fed controls. Morphologically, mitochondria of ethanol‐fed baboons were larger than those of pair‐fed controls. However, the mitochondrial protein content per mitochondrial DNA was unchanged. From these results, we conclude that, morphologically and functionally, hepatic mitochondria in baboons are altered by chronic ethanol consumption; it is noteworthy that these changes are fully developed already at the fatty liver stage, and that morphological alteration appears to reflect the damage of mitochondrial membranes rather than an

ISSN:0270-9139    

DOI:10.1002/hep.1840040201

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

AbstractA Bolivian population of squirrel monkeys,Saimiri sciureus, exhibits several features of Gilbert's syndrome in man, and is proposed as a nonhuman primate model of the condition. The Bolivian population was found to have higher fasting (40.6 ± 2.7μM;mean ± S.E.) and postcibal (9.9 ± 0.9μM)plasma unconjugated bilirubin concentrations (p<0.001) than a closely related Brazilian population (fasting 5.5 ± 0.7μM);postcibal (2.4 ± 0.7μM).After intravenous administration of [3H]bilirubin as a tracer dose or at 3.4 μmoles per kg body weight, there was delayed plasma clearance in the Bolivian monkeys. Hepatic UDP‐glucuronyl transferase activity for bilirubin (164 ± 25 nmoles per 30 min per gm liver) and biliary bilirubin diglucuronide to monoglucuronide ratios (2.9 ± 0.2) were lower in Bolivian monkeys than in Brazilians (421 ± 36 nmoles per 30 min per gm liver‐p<0.01 and 4.1 ± 0.1–p<0.02, respectively). Hepatic cytosol glutathione‐S‐transferase B activity (ligandin) levels were similar for the two populations. After phenobarbital therapy, fasting (11.1 ± 0.9μM)and postcibal (5.3 ± 1μM)plasma bilirubin concentrations in Bolivian monkeys were significantly reduced (p<0.001). Sulfobromophthalein clearance was slightly slower in the Bolivian than in the Brazilian monkeys. SGOT, lactate dehydrogenase, ‐γ‐glutamyl transpeptidase and alkaline phosphatase activities were not increased in Bolivians. Fasting serum conjugated bile salt concentrations in Bolivian monkeys were lower than that in Brazilian monkeys (p<0.01). Erythrocyte survival and hematological measurements wer

ISSN:0270-9139    

DOI:10.1002/hep.1840040202

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

Abstractγ‐Aminobutyric acid (GABA) is a potent inhibitory neurotransmitter which is synthesized by the enteric bacterial flora and delivered into portal venous blood. To determine whether the liver is likely to play an important role in regulating serum GABA levels, the uptake and metabolism of [3H]GABA by three populations of cells isolated from rat liver were studied. GABA was specifically taken up by hepatocytes but not by endothelial or Kupffer cells. Uptake by hepatocytes was saturable, as well as time and sodium dependent. At 0.5°C, a temperature at which binding of GABA to the cell surface is considered to be the predominant component of the uptake process, the apparent affinity constant (Km) was 0.82μMand a minimum value for binding velocity (Vmax) was 0.13μMper min per 5 ± 105cells. Uptake of [3H]GABA by hepatocytes was markedly inhibited by excess unlabeled GABA (95%), a‐aminoisobutyric acid (66%) and bicuculline (58%), but was inhibited much less by alanine (16%) and leucine (29%). These findings suggest that GABA binds specifically to the high affinity acceptor of the A amino acid transport system of rat hepatocytes. Impaired function of this transport system in liver failure could contribute to increased circulating levels

ISSN:0270-9139    

DOI:10.1002/hep.1840040203

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

AbstractIt has previously been shown in an animal model of hepatic encephalopathy (HE) that the number of receptors for the inhibitory neurotransmitter, γ‐aminobutyric acid (GABA), increases and that the number of receptors for the excitatory neurotransmitter, glutamate, decreases. To determine the functional status of other neurotransmitter systems in HE, measurements were made of the specific binding of other neurotransmitters to synaptic membranes prepared from the brains of normal rabbits and rabbits in HE due to galactosamine‐induced acute liver failure. The development of HE was associated with: (i) a decrease in the density (Bmax) of receptors for the two excitatory amino acid neurotransmitters, aspartate and kainic acid; (ii) an increase in the Bmaxof both the low and high affinity binding site for strychnine, a marker for the inhibitory neurotransmitter glycine; (iii) a decrease in the affinity (Kd) of receptors for dopamine, and (iv) no appreciable change in either the specific binding of [3H]D‐ala2‐methionine enkephalinamide or [3H]naloxone, markers for opiate receptors, or in the Bmaxor the Kdof receptors for acetylcholine. If it is assumed that the sensitivity of the brain to neurotransmitters varies directly with the density of neurotransmitter receptors, HE may be associated with increased sensitivity to inhibitory amino acid neurotransmitters and decreased sensitivity to excitatory amino acid neurotransmitters. Thus, the observed changes in neurotransmitter receptors in HE afford a feasible pathophysiological basis for the mediation of the neural inhibiti

ISSN:0270-9139    

DOI:10.1002/hep.1840040204

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

AbstractHybrid cell lines which secreted antibodies to liver‐specific membrane lipoprotein (LSP) were obtained by immunizing SMA and BALB/c mice with human LSP and fusing their splenocytes with the myeloma cell line P 3‐NSI/l‐Ag 4‐l. The secretion of antibody to LSP (anti‐LSP) was monitored by binding to a human hepatocellular carcinoma cell line, SK‐Hep‐1, which possesses surface membrane LSP, and to125I‐antimouse F(ab')2antibody in radiobinding assay, and by reacting with125I‐LSP in double‐antibody radioimmunoassay. From four separate cell fusions, seven secreting hybrids were cloned by dilutional techniques. Of these, four cell lines produced antibodies reacting with a wide variety of cells. The culture supernatants of the remaining three (6D6, 6G3 and 8F10) demonstrated the strongest binding activities against SK‐Hep‐1 among the various kinds of cell lines tested. However, binding with other cell lines, including renal cancer cells (SK‐RC‐6) and myeloid cell (HL‐60) also occurred. Absorption test of ascitic fluids derived from 6D6 showed that ascitic fluids lost their capacity to bind to target SK‐Hep‐1 cells when absorbed with SK‐Hep‐1. Similarly absorption by SK‐RC‐6 and HL‐60 removed almost all of the binding activity of ascitic fluids. Moreover, the binding activities of the ascitic fluids to SK‐RC‐6 and HL‐60 were eliminated when absorbed with SK‐RC‐6, HL‐60 and SK‐Hep‐1. The present study indicates that our LSP preparation contains nonspecific organ antigens, and although LSP exists on liver cell membrane, It is also f

ISSN:0270-9139    

DOI:10.1002/hep.1840040205

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

AbstractIn this study, we describe a radioimmunoassay to detect liver membrane binding antibodies. The assay was designed to exclude binding of aggregated IgG or immune complexes to Fc 7 receptors of hepatocytes. When this assay was applied to sera from 142 patients, antibodies were found in highest titer in patients with autoimmune chronic active hepatitis, rarely in patients with hepatitis B virus‐induced chronic active liver disease, and in 32% of patients with primary biliary cirrhosis. IgM antibodies were found in 100% of patients with acute Type A but not B or non‐A, non‐B hepatitis. IgA class antibodies were found in the sera of 57% of patients with alcohol‐induced hepatitis. All patient groups showing significant titers of liver membrane antibodies display the lesion of piecemeal necrosis except those with alcohol‐induced hepatitis. Further studies are needed to determine whether this antibody is the cause of t

ISSN:0270-9139    

DOI:10.1002/hep.1840040206

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

AbstractHepatocytes incubated with 25μM.[3H]taurocholate rapidly deplete the extracellular medium of [3H]taurocholate and achieve a steady‐state level of intracellular bile salt within 15 min. Exposure of cells at steady state ith extracellular taurocholate to the catecholamines norepinephrine or epinephrine results in release of3H from the cells into the incubation medium; the3H released represents almost exclusively unmetabolized [3H]taurocholate. The hierarchy of effectiveness of the catecholamines, norepinephrine ≈ epinephrine>phenylephrine ≫ isoproterenol, is indicative of an α‐adrenergic mechanism. Induction of [3H]taurocholate release by norepinephrine is inhibited by the β‐antagonists phenoxybenzamine and phentolamine and by chlorpromazine, but is not affected by the β‐antagonist propranolol, further supporting an α‐adrenergic basis for this phenomenon. Arginine vasopressin, at concentrations of 1 ± 10−9M and greater, also induces bile salt release. Classicalα‐and β‐antagonists have minimal effects on vasopressin induced bile salt release. While the peptide hormones angiotensin and oxytocin are, alone, relatively ineffective inducers of bile salt release, oxytocin potentiates the induction of bile salt release by vasopressin, suggesting complex interactions with membrane receptor function. Further studies assessing the interaction of sympathetic neurotransmitters and peptide hormones with bile salt transport and release in the hepatocyte may provide insight into the regulation of hepatic secretory fu

ISSN:0270-9139    

DOI:10.1002/hep.1840040207

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

AbstractPartial hepatectomy and a single intravenous injection of zymosan were used to provoke expansion of the Kupffer cell population in rat liver. The number of Kupffer cells per microscopic field increased exponentially for 4 to 5 days after either stimulation. During this exponential growth phase, high mitotic activity of Kupffer cells was observed.The rate of mitosis, based on counts of cells arrested in metaphase by vinblastin, was compared with the increase in total cell population. During the first 3 days after partial hepatectomy, local proliferation was sufficient to explain the increase in population since the mean potential doubling time was 1.3 days compared to an observed doubling time of 3.7 days. During the first 3 days after zymosan stimulation, observed doubling time was 4.3 days compared with the mean potential doubling time of 5.2 days which led to the conclusion that growth is largely due to local proliferation of Kupffer cells. In both experimental situations, extrahepatic recruitment of “resident‐type” macrophages was required during the last 2 days of the growth phase, since mitotic activity became too low to explain the observed growth. Proliferating Kupffer cells had characteristics of mature resident macrophages and were, therefore, considered to be different from elicited “exudate‐type” cells, such a

ISSN:0270-9139    

DOI:10.1002/hep.1840040208

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

AbstractAn antibody, which is distinct from the HBsAg, and reacts with antigenic sites on Dane particles HBcAg and HBeAg, was studied by radioimmunoprecipitation of radioactive intact hepatitis B virions in sera obtained early in the course of acute hepatitis type B. The antibody, previously termed anti‐Dane particle (anti‐DP) antibody, was reactive with Dane particles and HBsAg particles obtained from HBeAg‐positive sera but not with HBsAg particles from anti‐HBe containing sera. The expression on virus particles of the evoking antigen correlated with levels of binding sites for polymerized human serum albumin (pHSA) as detected by solid‐phase radioimmunoassay. In acute hepatitis B sera, levels of anti‐DP antibody activity showed inverse correlation with expression of pHSA receptors on circulating virus particles, although the two reactivities were not mutually exclusive. In inhibition experiments, pHSA blocked precipitation of Dane particles by anti‐DP positive sera, while native human albumin and polymerized bovine albumin had no effect. The inhibition by pHSA of the anti‐DP reaction appeared specific since identical concentrations of pHSA did not interfere with precipitation of virus particles by anti‐HBs. Affinity chromatography studies with anti‐DP insolubilized on Sepharose 4B columns showed selective binding to the gel of radioactive Dane particles;125I‐HBsAg was not reactive. The binding of Dane particles to anti‐DP columns was completely inhibited when virus particles were applied to the gel in pHSA; pretreat‐ment of the column with pHSA did not affect the reaction. These results and the demonstration that anti‐DP positive sera were free of anti‐pHSA antibodies indicate that anti‐DP reacts with antigenic determinants on Dane particles that are involved in or by pHSA binding sites. Anti‐DP positive sera and IgG fractions inhibited expression of pHSA receptors on purified virus particles. Our findings support suggestions that the anti‐DP response may be relevant to the phase of virus neutralization, on the basis of the hypothesis that the virus receptor for pHSA could play a role in mediating virus access to hepatocytes which may have similar

ISSN:0270-9139    

DOI:10.1002/hep.1840040209

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY

摘要:

AbstractThe two subtypes of pigment gallstones, black and brown stones, differ in chemical composition and pathogenesis. We examined a black bilirubinate stone and a black phosphate stone (which represented opposite ends of the compositional spectrum of black noncarbonate stones), a black carbonate stone, and a brown pigment stone using scanning electron microscopy and microchemical techniques to determine if stone microstructure and microcomposition reflected different patterns of formation. The cross‐sectional surfaces of the black bilirubinate and black phosphate stones were smooth and homogenous. Electron probe microanalysis demonstrated high concentrations of sulfur and copper in the center of the black bilirubinate stone; sulfur was in a low valence state consistent with disulfide linkages in proteins. The brown stone was rough‐surfaced with lamellated bands on cross‐section. The lighter‐colored bands in this stone contained virtually all of the detected calcium palmitate, while the darker sections contained much more calcium bilirubinate. Plasma oxygen etching demonstrated a network of protein interdigitating with calcium bilirubinate salts in the black bilirubinate and black phosphate stones but not in the black carbonate or brown stones. Argon ion etching demonstrated that calcium bilirubinate was in a closely packed rod‐shaped arrangement in all three black stones but not in the brown stone. We conclude that the marked differences in structure and composition between the black noncarbonate and brown pigment gallstones support the hypothesis that the two major pigment gallstone types form by different mechanisms. In addition, the layered structures of the black carbonate and brown stones suggest that stone growth is affected by cyclic changes in biliary co

ISSN:0270-9139    

DOI:10.1002/hep.1840040210

出版商:W.B. Saunders    

年代:1984

数据来源: WILEY