Idiopathic portal hypertension.

Idiopathic portal hypertension is reported in five cases including one case of chronic arsenical intake and one case of chronic industrial vinyl chloride exposure. In all five cases the patients presented with gastrointestinal bleeding as the chief complaint. Physical examination was within normal limits except for splenomegaly in all. Results of liver function tests were normal, except for the relative clearance of sulfobromophtalein. A surgical liver biopsy specimen was obtained in all cases and showed moderate degrees of portal fibrosis, but no cirrhosis. Combined umbilicoportal, hepatic vein and superior mesenteric artery catheterization was performed in all cases. Hepatoportographies showed distortion of the intrahepatic portal venous system and cut-off of small portal venules. Porto-hepatic gradients ranged from 14.0 to 20.5 mm Hg. The portal hypertension was both sinusoidal and presinusoidal in nature but mainly presinusoidal. Hepatic extraction of indocyanine green and of albumin microaggregates was normal, thereby suggesting normal functional portal blood supply to the liver. The patients with arsenical or vinyl chloride exposure could not be differentiated from the other three patients with idiopathic portal hypertension. These results suggest that idiopathic portal hypertension may be related to domestic or industrial exposure to other hepatotoxins.

Effects of chronic acetone administration on ethanol-inducible monooxygenase activities in the rat.

Liver microsomal monooxygenase activities known to be ethanol-inducible were determined in female Sprague-Dawley rats after 2-week treatment with 1% (v/v) acetone. Daily acetone intake was in the order of 1.2 g/kg. The final body weight, liver weight and microsomal protein content of acetone-treated rats were identical to those of untreated controls. Microsomal NADPH-cytochrome c reductase activity was also unaffected, while cytochrome P-450 content was only increased 12-18%. Ethanol-inducible p-nitrophenol hydroxylation, aniline hydroxylation and 7-ethoxycoumarin O-deethylation activities were enhanced 5.3-, 4.4- and 2.6-fold, respectively, by chronic acetone treatment. The sex-dependent inducing effect of ethanol on benzphetamine N-demethylation activity in female rats was not observed however, after acetone. Addition of acetone in vitro had a stimulatory effect on aniline hydroxylation by microsomes from control and acetone-induced rats. Acetone, however, was found to be a competitive inhibitor of p-nitrophenol hydroxylation activity (apparent Ki = 1.8 mM), an observation suggesting that p-nitrophenol is a more selective substrate than aniline for rat liver ethanol- and acetone-inducible cytochrome P-450j. Interruption of the chronic acetone treatment for 24 hr resulted in the almost complete disappearance of its inducing affects, this treatment apparently reproducing only the rapidly reversible preferential inducing effects of chronic ethanol administration. This experimental model of induction by acetone in the rat, when compared to chronic ethanol administration, would thus permit a more selective look at the consequences of these common inducing effects in particular, with respect to drug metabolism and toxicity in vivo, and this, in the absence of the hepatotoxic effects of ethanol itself.

Differences in the duration of the enhancement of liver mixed-function oxidase activities in ethanol-fed rats after withdrawal.

Liver microsomal mixed-function oxidase activities were determined in female Sprague-Dawley rats after 3 weeks of ethanol feeding and for up to 10 days after withdrawal. Ethanol (36% of total calories) was administered in a high fat liquid diet and was replaced isocalorically by carbohydrates in controls. Chronic ethanol feeding similarly enhanced both microsomal cytochrome P-450 content and benzphetamine N-demethylase activity, per mg of protein, and resulted in a disproportionate increase in both aniline hydroxylase and 7-ethoxycoumarin O-deethylase activities. A 6- to 7-day withdrawal period was apparently necessary for the overall disappearance of these effects of ethanol. Marked differences, however, were seen in the time courses of return of these variables to control levels, as also indicated by changes, during this period and specially during the first 24 hr after withdrawal, in the apparent molar activity of the microsomal fraction with the three substrates tested. The results were interpreted as indicating that the distinct ethanol-inducible cytochrome P-450 isozyme, with a high specific activity toward aniline, undergoes a very rapid turnover in liver microsomes. Induction of another form of cytochrome P-450, differing from the former by its slower turnover rate, would explain the induction by ethanol of 7-ethoxycoumarin O-deethylase activity. The withdrawal of ethanol was followed by a rapid but transient increase in benzphetamine N-demethylase activity above the ethanol-induced level, at a time when other activities were rapidly declining. This could suggest that the microsomal content of other cytochrome P-450 isozyme(s), with high specific activity toward this substrate, would also be temporarily altered during ethanol withdrawal. Important alterations in microsomal cytochrome P-450-dependent mixed-function oxidase activities occurred during the initial 24-hr period of withdrawal, even in the absence of a change in microsomal cytochrome P-450 content, indicating that the effects of chronic ethanol ingestion on hepatic drug-metabolizing enzyme activities may also be highly dependent on the proximity of ethanol intake.

Comparison of three methods for the elimination of the labile fraction of HbA1.

Three different procedures were used to remove the "labile" fraction in the chromatographic quantitation of hemoglobin A1 (HbA1) by a minicolumn assay: (a) preincubation of the erythrocytes at 37 degrees C in isotonic saline for 4 h, (b) preincubation in the presence of semicarbazide-aniline at pH 5.0 for 30 min, and (c) preincubation in acetate buffer at pH 5.5 for 30 min. The results show that the two latter methods are not only more rapid but are also slightly more effective. The use of the acetate buffer is preferred because this reagent is more easily prepared and also because the presence of semicarbazide and aniline did not markedly accelerate the dissociation of Hb pre-A1c at pH 5.5. The procedure relies simply on the greater instability of Schiff base in acidic solution. There is a significant correlation between the "labile" fraction and the plasma glucose concentration at sampling time. The results support the view that the elimination of the "labile" precursor is essential to preserve the utility of the assay.

Ethanol-inducible liver cytochrome P-450 in the rat: relative specificity for ethanol oxidation activity in vitro.

Ethanol induces in rat liver microsomes a form of cytochrome P-450 differing in substrate specificity from cytochrome P-450 species present in controls or in rats treated with phenobarbital or 3-methylcholanthrene. Its relative capacity to oxidize ethanol remained to be determined and was studied using highly purified cytochrome P-450 preparations and comparing their activity in a reconstituted microsomal ethanol oxidizing system (MEOS). On a molar basis, reconstituted MEOS activity was found to be highest when assayed with ethanol-inducible cytochrome P-450, intermediate with cytochrome P-450 from phenobarbital-treated rats, and lowest with cytochrome P-450 from controls or 3-methylcholanthrene-treated rats. A decrease in apparent Km for ethanol was also found to be associated with higher MEOS activity of ethanol-inducible cytochrome P-450. The induction by ethanol of a catalytically distinct form of cytochrome P-450, and the comparatively high ethanol oxidizing activity of this cytochrome P-450 species, are in accordance with the MEOS hypothesis.

[Histochemical and ultrastructural study of the rat oral mucosa, after chronic administration of alcohol]. / Etude histochimique et ultrastructurale de la muqueuse buccale du rat, après administration chronique d'alcool.

In order to study the action of alcohol on the oral mucosa, Sprague-Dawley female rats, receiving an alcohol rich diet, were sacrifical as well as their controls, 98, 200 and 290 days after the experiment start and their oral mucosa studied histochemically and ultrastructurally. In the alcoholic animal, 1) the epithelium was thickened from day 98 on and SS and SH groups were detected in the keratin; 2) at this time interval, positive acid phosphatase areas were noted. Under the electron microscope, myelin figures were observed phosphatase areas were noted. Under the electron microscope, myelin figures were observed between cells on days 98 and 200. Cells undergoing autolysis could explain the lysosomial enzyme activity; 3) the DNA activity assessed by methyl-pyronine green stain was increased after 200 and 290 days. This activity was correlated at these time intervals with the increase of the mitosis number; 4) succinodeshydrogenase showed an increased activity on days 200 and 290. The mitochondria often of large size showed no ultrastructural changes even on day 290; 5) the vessels, already on day 98, then on days 200 and 290, showed a decrease in alkaline phosphatase reactivity with occasional thinnings of the wall. These modifications suggested that alcohol was able to modify the integrity of oral mucosa cells in the rat, perhaps by modifying the quality of the cell walls.

Effects of chronic ethanol administration in the rat: relative dependency on dietary lipids. II. Paradoxical role of linoleate in the induction of hepatic drug-metabolizing enzymes in vitro.

The effect of chronic ethanol administration on the hepatic microsomal cytochrome P-450 content and activities of NADPH - cytochrome P-450 reductase (EC 1.6.2.4), benzphetamine demethylase, aniline hydroxylase (EC 1.14.14.1), and of the microsomal ethanoloxidizing system were studied in various dietary models. When ethanol was given with linoleate as the only source of dietary lipid, the ethanol induction of these parameters was greater with diets containing 2 or 5% of total calories as linoleate than with diets containing 10% of total calories as linoleate. By contrast, when ethanol was given with high fat (35% of total calories) diets, the ethanol induction of these same parameters was slightly greater when linoleate provided 10% of total calories than when it provided 3% of calories. The apparent effect of dietary linoleate on the induction, by ethanol, of microsomal drug-metabolizing enzymes is markedly different when linoleate is given as the only source of dietary lipid as opposed to when it is given with other dietary lipids. Thus, conclusions on the effect of ethanol on hepatic microsomal drug-biotransformation enzymes, drawn from studies with dietary models in which linoleate provides the only source of dietary lipid, connot be extended to dietary modles of more complex lipid composition. When given as the only source of lipid, 2% of total calories in linoleate appears optimal for basal activity and inductibility, by ethanol, of mixed-function oxidases.

Alcohol induced changes of carbohydrate metabolism [author's transl]. / Alkoholbedingte störungen des kohlenhydratstoffwechsels.

It is evident that ethanol by itself or one of its metabolites produces alterations in transport, metabolism and disposition of carbohydrates. Ethanol acts via changes in the redox state of co-factors; e.g. ethanol-induced hypoglycemia is due, partly, to the inhibition of hepatic gluconeogenesis by ethanol as a consequence of the increased NADH2/NAD ratio in patients whose glycogen stores are already depleted. On the other hand, hyperglycemia has also been described in patients with alcoholism. Although its mechanism is still obscure, abnormal hormonal secretion of insulin, catecholamines and glucocorticoids has been incriminated. Finally, structural changes of the liver and pancreas such as cirrhosis and pancreatitis produced by chronic alcohol consumption should also be considered as pathogenetic factors in a variety of clinical states involving deranged carbohydrate metabolism.

Effect of chronic ethanol administration on bromobenzene liver toxicity in the rat.

Female Sprague-Dawley rats were pair-fed a nutritionally adequate liquid diet containing either ethanol or isocaloric carbohydrate for 3 weeks. In vitro studies showed that chronic ethanol pretreatment preferentially increased the liver microsomal biotransformation of bromobenzene to p-bromophenol (via the toxic 3,4-epoxide) rather than to o-bromophenol (via the nontoxic 2,3-epoxide) and could thus potentiate bromobenzene hepatotoxicity. Bromobenzene administration (500 mg/kg body weight, ip), after an overnight fast, was associated in ethanol-pretreated rats with greater and accelerated liver glutathione depletion and subsequent decrease in liver cytochrome P-450 content than in controls. As assessed histologically and by determination of the rise in activities of serum enzyme markers of liver necrosis, chronic ethanol pretreatment, however, mainly resulted in earlier onset and resolution of bromobenzene-induced liver necrosis, with only a mild increase in the maximal severity of liver lesions. These results suggest that the twofold increase in liver microsomal bromobenzene 3,4-epoxidation by ethanol, being much less than that seen after phenobarbital pretreatment in our animal model and in that of others, is apparently not sufficient to markedly affect the severity of bromobenzene-induced liver toxicity.

Influence of ethanol on hepatic glutathione content and on the activity of glutathione S-transferases and epoxide hydrase in the rat.

Chronic ethanol administration to female rats for 3 weeks was associated with a 60% increase in liver microsomal cytochrome P-450 content. This effect was accompanied by a similar increase in microsomal epoxide hydrase activity, in the presence of styrene oxide, and by significant increases in liver glutathione concentration and cytosolic glutathione S-transferase activities. A time-course study showed that the elevation of liver glutathione concentration seen after 3 weeks of ethanol consumption was a transient phenomenon, not observed after prolonged (23 weeks) ethanol intake and preceded, in the first 10-12 days of ethanol administration, by a decrease below control levels. The latter occurred at a time when the cytochrome P-450 content and the activity of glutathione S-transferases reached maximal increases to levels twice as high as those seen from 3 to 23 weeks of ethanol consumption. These observations show that chronic ethanol consumption may thus affect the hepatotoxicity of xenobiotics susceptible to cytochrome P-450-dependent bioactivation by influencing both this pathway and those involved in the inactivation of reactive metabolites. They also suggest that vulnerability of the liver to such hepatotoxins may be influenced by the duration of exposure to ethanol.

Inhibition of liver regeneration by chronic alcohol administration.

Liver regeneration is the common mechanism whereby a patient recovers form a liver injury. In the western world, ethanol is the single most important aetiological factor associated with liver disease, and it appears crucial to determine if ethanol interferes with liver regeneration. We studied the response to a 70% hepatectomy in 240 rats receiving a nutritionally adequate diet containing 36% of their calories as ethanol for three weeks and their pair-fed controls receiving a liquid diet where ethanol is isocalorically replace with carbohydrates. Criteria of liver regeneration were: incorporation of 3H-thymidine in hepatocyte DNA (cpm/10 microgram DNA) and number of hepatocyte labelled nuclei on autoradiography per 100 high power fields. Controls displayed the usual response with peak activity of liver regeneration at 24 hours. Consumption of ethanol was associated with a statistically significant reduction of liver regeneration by both criteria for up to 72 hours after a 70% hepatectomy and delayed the peak of regenerative activity by 24 hours. This inhibiting effect was not related to the presence of alcohol in blood nor to hepatic microsomal enzyme induction by ethanol nor to widespread necrosis of hepatocytes. This effect was reversible after one week of abstinence. This impairment of liver cell renewal by ethanol may be of major significance in the severity and outcome of alcohol-related liver injury.

Aniline hydroxylation and 7-ethoxycoumarin O-deethylation activities in solubilized and partially resolved liver cytochromes P-450 from ethanol-fed rats.

Chronic ethanol administration in female rats enhances the apparent molar activity of liver microsomes for aniline hydroxylation and 7-ethoxycoumarin O-deethylation. Microsomal cytochromes P-450 from ethanol-fed and control rats have been solubilized and partially resolved in six fractions by anion-exchange chromatography. Induction of aniline hydroxylase activity by ethanol was associated with marked increases in the turnover numbers of the more basic cytochrome P-450 containing fractions in a reconstituted aniline hydroxylation system. Cytochrome P-450, exhibiting by far the highest 7-ethoxycoumarin O-deethylase activity, was eluted in a relatively acidic fraction; its turnover number with 7-ethoxycoumarin after ethanol consumption, however, did not differ significantly from that of the corresponding fraction from control microsomes. These observations suggest that induction of liver microsomal mixed function oxidases by ethanol may reflect the contribution of more than one cytochrome P-450 isozyme.

Morphologic changes of the esophageal mucosa in the rat after chronic alcohol ingestion.

Fifteen litter-matched pairs of Sprague-Dawley rats were divided into two groups, one fed an alcoholic diet and the other fed an isocaloric but non-alcoholic diet. 5 animals each of the experimental and control groups were sacrificed at 98, 200 and 290 d. The upper part of esophagus was fixed for morphological analysis of semi-fine sections. The following histological observations were made on the oral-esophageal mucosa of the alcohol-consuming animals: An epithelial atrophy was observed between 200 and 290 d of alcoholisation . This atrophy was not the result of a decrease in the number of epithelial layers, but was associated with a decrease in basal cellular size. A basal cell pleomorphism and a tendency towards epithelial dysplasia were the rule after long time alcohol consumption. These observations reflect features resembling to those seen in Plummer- Vinson syndrome, a precancerous state in humans.

Light chain disease and massive proteinuria.

We describe the case of a 64-year-old man with lambda type light chain disease, in whom panhypogammaglobulinemia was associated with anemia, massive Bence Jones proteinuria (24.6 g/L), and renal failure. Lambda type light chains were present in the serum.