Imbalance of the autonomic nervous system at night in women with gestational diabetes

AIMS

Autonomic nervous system dysfunction is observed in Type 2 diabetes. As gestational diabetes is a potent risk factor of later Type 2 diabetes, we set out to determine whether autonomic nervous system imbalance could already be observed in women with this condition. Because activity of the sympathetic nervous system tends to be relatively stable in the nocturnal hours, we performed the study at night.

RESEARCH DESIGN AND METHODS

We studied 41 women with gestational diabetes, 22 healthy pregnant controls and 14 non-pregnant controls. We assayed plasma noradrenaline at 24.00, 04.00 and 07.00 h and performed an overnight Holter recording for heart rate variability analysis. In addition, we assayed plasma adrenomedullin, a cardiovascular protective hormone.

RESULTS

Compared with non-pregnant controls, plasma noradrenaline levels were increased at 04.00 and 07.00 h in the gestational diabetic (P = 0.003) and pregnant control (P = 0.002) groups, with no difference between them. Heart rate variability, very-low-frequency and low-frequency power were lower in pregnant groups compared to the non-pregnant controls. Heart rate variability remained unchanged between specified sampling times in the gestational diabetic group, in contrast to fluctuation seen in the control groups.

CONCLUSIONS

Gestational diabetes, compared with normal pregnancy, seems not to be a state of overall sympathetic nervous system activation. At the heart level, however, an inhibitory effect on autonomic nervous system modulation was seen. Plasma noradrenaline and heart rate variability correlated well, supporting the use of this function in future studies of overall sympathetic activity during pregnancy.

Common candidate gene variants are associated with QT interval duration in the general population

OBJECTIVES

QT interval prolongation is associated with increased risk of sudden cardiac death at the population level. As 30-40% of the QT-interval variability is heritable, we tested the association of common LQTS and NOS1AP gene variants with QT interval in a Finnish population-based sample.

METHODS

We genotyped 12 common LQTS and NOS1AP genetic variants in Health 2000, an epidemiological sample of 5043 Finnish individuals, using Sequenom MALDI-TOF mass spectrometry. ECG parameters were measured from digital 12-lead ECGs and QT intervals were adjusted for age, gender and heart rate with a nomogram (Nc) method derived from the present study population.

RESULTS

The KCNE1 D85N minor allele (frequency 1.4%) was associated with a 10.5 ms (SE 1.6) or 0.57 SD prolongation of the adjusted QT(Nc) interval (P=3.6 x 10(-11)) in gender-pooled analysis. In agreement with previous studies, we replicated the association with QT(Nc) interval with minor alleles of KCNH2 intronic SNP rs3807375 [1.6 ms (SE 0.4) or 0.08 SD, P=4.7 x 10(-5)], KCNH2 K897T [-2.6 ms (SE 0.5) or -0.14 SD, P=2.1 x 10(-7)] and NOSA1P variants including rs2880058 [4.0 ms (SE 0.4) or 0.22 SD, P=3.2 x 10(-24)] under additive models.

CONCLUSIONS

We demonstrate that each additional copy of the KCNE1 D85N minor allele is associated with a considerable 10.5 ms prolongation of the age-, gender- and heart rate-adjusted QT interval and could thus modulate repolarization-related arrhythmia susceptibility at the population level. In addition, we robustly confirm the previous findings that three independent KCNH2 and NOSA1P variants are associated with adjusted QT interval.

Non-endoscopic diagnosis of atrophic gastritis with a blood test. Correlation between gastric histology and serum levels of gastrin-17 and pepsinogen I: a multicentre study

BACKGROUND AND AIMS

Serum levels of gastrin-17 (S-G-17) and pepsinogen I (S-PGI) are biomarkers of gastric antral and corpus mucosa, respectively. In a prospective multicentre investigation, we determined whether these tests, together with the assay of Helicobacter pylori antibodies, are a non-endoscopic tool for the diagnosis of atrophic gastritis.

MATERIALS AND METHODS

The series comprised 404 consecutive adult outpatients undergoing diagnostic upper-gastrointestinal endoscopy for various dyspeptic symptoms in five outpatient clinics. Gastric biopsies from the antrum and corpus (at least two biopsies from both sites) were available from all patients, and they were evaluated according to the guidelines of the updated Sydney system. S-PGI and S-G-17 were assayed with ELISA methods using monoclonal antibodies to pepsinogen I and amidated gastrin-17. In addition to the fasting level (S-G-17(fast)), a postprandial S-G-17 (S-G-17(prand)) level was measured 20 min after ingestion of a protein-rich drink. H. pylori antibodies were determined using a polyclonal EIA method.

RESULTS

S-G-17(prand) (and S-G-17(fast)) and S-PGI levels decreased with increasing grade of atrophy of the antrum or corpus, respectively. S-G-17(prand) levels were significantly lower in patients with advanced (moderate or severe) atrophic antral H. pylori gastritis than in those with non-atrophic H. pylori gastritis. All patients with a resected antrum demonstrated S-G-17(prand) levels that were almost undetectable. Of the nine patients with an H. pylori-positive moderate or severe atrophic antral gastritis, six had S-G-17(prand) levels below 5 pmol/l. Similarly, S-PGI levels were significantly lower in patients with advanced corpus atrophy than in those without. Of the 45 patients with moderate or severe corpus atrophy in endoscopic biopsies, 35 patients had S-PGI levels < 25 microg/l. By using the cut-off levels for S-G-17(prand) and S-PGI with the best discrimination, the sensitivity and specificity of the blood test panel in delineation of patients with advanced atrophic gastritis (either in the antrum or the corpus, or both) were 83% and 95%, respectively. The predictive values of the positive and negative test results were 75% and 97%, respectively. In the diagnosis of atrophic gastritis, the application of S-G-17(fast) showed a slightly lower sensitivity and specificity than the application of S-G-17(prand) as a biomarker for antral atrophy.

CONCLUSIONS

The diagnosis of atrophic gastritis obtained with the blood test panel of S-G-17, S-PGI and H. pylori antibodies is in good agreement with the endoscopic and biopsy findings. The panel is a tool for non-endoscopic diagnosis and screening of atrophic gastritis.

Postmyocardial infarction patients susceptible to ventricular tachycardia show increased T wave dispersion independent of delayed ventricular conduction

INTRODUCTION

Experimentally, both delayed ventricular conduction and nonhomogeneous ventricular repolarization contribute to reentrant arrhythmias. We tested the hypothesis that increased T wave dispersion is independent of delayed ventricular conduction associated with arrhythmia vulnerability in postmyocardial infarction (post-MI) patients.

METHODS AND RESULTS

We studied 32 post-MI patients with clinical or inducible monomorphic ventricular tachycardia (VT group), 28 post-MI patients without arrhythmias (MI group), and 13 healthy controls, using magnetocardiographic (MCG) mapping with signal averaging. Twelve-lead ECG was the reference. Filtered QRS duration (fQRS) and T wave peak to T wave end interval (TPE) were used as measures of ventricular conduction and nonhomogeneity in ventricular repolarization, respectively. In MCG, the VT group showed the longest fQRS (135+/-34 msec vs 114+/-22 msec in the MI group; P = 0.012). Mean TPE and maximum TPE in VT versus MI groups were 78+/-9 msec versus 70+/-6 msec (P < 0.001) and 117+/-23 msec versus 104+/-19 msec (P = 0.020), respectively. Maximum TPE did not correlate with fQRS in the VT group (r = 0.063; P = NS) but did correlate in the MI group (r = 0.396; P = 0.037). For identification of post-MI patients prone to VT, selection of cutoff values for fQRS >140 msec and mean TPE >81 msec gave sensitivity and specificity of 41% and 89%, and 31% and 96%, respectively. Their combination increased sensitivity to 63% while maintaining 89% specificity.

CONCLUSION

Post-MI patients susceptible to VT show increased T wave dispersion independent of delayed ventricular conduction.

Variable protection of beta 3-integrin--deficient mice from thrombosis initiated by different mechanisms

Platelet integrin alpha IIb beta 3 (GPIIb/IIIa) plays a central role in the initiation of arterial thrombosis, but its contribution to disseminated microvascular thrombosis is less well defined. Therefore, wild-type mice (beta 3(+/+)), beta 3-integrin-deficient mice (beta 3(-/-)), and wild-type mice treated with a hamster monoclonal antibody (1B5) that blocks murine alpha IIb beta 3 function were tested in models of large-vessel and microvascular thrombosis. In the large-vessel model, ferric chloride was used to injure the carotid artery, and the time to thrombosis was measured. In beta 3(+/+) mice, the median time to occlusion was 6.7 minutes, whereas occlusion did not occur in any of the beta 3(-/-) mice tested (P <.001). Fab and F(ab')(2) fragments of 1B5 increased the median time to occlusion. To initiate systemic intravascular thrombosis, prothrombotic agents were administered intravenously, and platelet thrombus formation was monitored by the decrease in circulating platelet count. Three minutes after the injection of adenosine diphosphate (ADP), collagen + epinephrine, or tissue factor, the platelet counts in beta 3(+/+) mice decreased by 289, 424, and 429 x 10(3)/microL, respectively. beta 3(-/-) mice and wild-type mice pretreated with 1B5 Fab (1 mg/kg, IP) were nearly completely protected from the effects of ADP. In contrast, beta 3(-/-) mice were only partially protected from the effects of collagen + epinephrine and minimally protected from the effects of tissue factor. In all cases, less fibrin became deposited in the lungs of beta 3(-/-) mice than in wild-type mice. These results suggest that though alpha IIb beta 3 plays a dominant role in large-vessel thrombosis, it plays a variable role in systemic intravascular thrombosis. (Blood. 2001;98:1055-1062)

Repolarization abnormalities detected by magnetocardiography in patients with dilated cardiomyopathy and ventricular arrhythmias

INTRODUCTION

Abnormal repolarization is one of the acknowledged mechanisms leading to malignant ventricular arrhythmias. We used a novel magnetocardiographic technique to investigate the role of inhomogeneous repolarization in patients with nonischemic dilated cardiomyopathy prone to sustained ventricular arrhythmias.

METHODS AND RESULTS

Forty-nine dilated cardiomyopathy patients were studied, 18 with a history of sustained ventricular tachycardia (n = 6) or ventricular fibrillation (n = 12) and 31 with no ventricular arrhythmias. The magnetocardiogram was registered and QT apex and QT end intervals were determined by a computer algorithm. Inhomogeneity of repolarization was characterized with indices describing QT apex and QT end dispersion, and T wave end duration. In addition, time-domain late fields of the QRS complex in magnetocardiography and QT dispersion in 12-lead ECG were determined. T wave end was longer in the arrhythmia group in patients with sinus rhythm (87 +/- 15 msec vs 73 +/- 12 msec; P = 0.005) and in those not having bundle branch block. Magnetocardiographic late fields of the QRS complex were not different between groups. QT apex and end dispersion on magnetocardiography or 12-lead ECG showed no difference.

CONCLUSION

Prolongation of the end part of the T wave revealed by magnetocardiography is related to malignant ventricular arrhythmias in dilated cardiomyopathy. The results suggest that abnormal repolarization rather than delayed conduction underlies the arrhythmias in this disease.

In vitro acetaldehyde formation by human colonic bacteria

Incubation of human colonic contents with various ethanol concentrations (2.75-44 mM) in vitro at 37 degrees C resulted in significant accumulation of acetaldehyde--a toxic and highly reactive compound. At pH 9.6, all samples produced notable acetaldehyde concentrations (58 (13) microM; mean (SEM)) even from the lowest (2.75 mM) ethanol concentration, and the production of acetaldehyde increased lin-early with rising ethanol concentration (r = 0.97; p < 0.005), reaching a peak concentration of 238 (37) microM at 44 mM ethanol. The formation of acetaldehyde took place rapidly, as almost 50% of acetaldehyde formed during the total eight hour incubation was detectable after one hour, and 75% of the total after four hours. Maximal acetaldehyde production from 22 mM ethanol occurred at pH 9.6 (160 (35) microM) but appreciable concentrations were also seen at pH 7.4 (110 (38) microM) and pH 6.0 (63 (19) microM). At pH 4.0, by contrast, acetaldehyde formation was negligible (17 (5) microM). 4-Methylpyrazole, a potent inhibitor of alcohol dehydrogenase, showed a decreasing effect on acetaldehyde production in vitro but first at a concentration of 100 mM. Considerable acetaldehyde production by human colonic bacteria--if it occurs also in vivo--could constitute a risk factor for rectal cancer in heavy drinkers and also provide a pathogenetic mechanism for alcohol induced diarrhoea.

Lateral mobility of lipid analogues and GPI-anchored proteins in supported bilayers determined by fluorescent bead tracking

Lipid analogues and glycosylphosphatidylinositol (GPI)-anchored proteins incorporated in glass-supported phospholipid bilayers (SBL) were coupled to small (30 nm diameter) fluorescent beads whose motion in the liquid phase was tracked by intensified fluorescence video microscopy. Streptavidin (St), covalently attached to the carboxyl modified surface of the polystyrene bead, bound either the biotinylated membrane component, or a biotinylated monoclonal antibody (mAb) directed against a specific membrane constituent. The positions of the beads tethered to randomly diffusing membrane molecules were recorded at 0.2 sec intervals for about 1 min. The mean square displacement (rho) of the beads was found to be a linear function of diffusion time t, and the diffusion coefficient, D, was derived from the relation, rho(t) = 4Dt. The values of D for biotinylated phosphatidylethanolamine (Bi-PE) dispersed in an egg lecithin:cholesterol (80:20%) bilayer obtained by this methodology range from 0.05 to 0.6 micron 2/sec with an average of mean value of D = 0.26 micron 2/sec, similar to the value of mean value of D = 0.24 micron 2/sec for fluorescein-conjugated phosphatidylethanolamine (Fl-PE) linked to St-coupled beads by the anti-fluorescein mAb 4-4-20 or its Fab fragment. These values of D are comparable to those reported for Fl-PE linked to 30 nm gold particles but are several times lower than that of Fl-PE in the same planar bilayer as measured by fluorescence photobleaching recovery, D = 1.3 microns 2/sec. The mobilities of two GPI-anchored proteins in similar SBL were also determined by use of the appropriate biotinylated mAb and were found to be mean value of D = 0.25 and 0.56 micron 2/sec for the decay accelerating factor (DAF, CD55) and the human Fc gamma RIIIB (CD16) receptors, respectively. The methodology described here is suitable for tracking any accessible membrane component.

The distribution of intracellular calcium chelator (fura-2) in a population of intact human red cells

Using quantitative fluorescence microscopy of red cells loaded non-disruptively with 1-2.5 mmol/l cells of fura-2, we examined the distribution of the incorporated free chelator among and within individual cells. Cytoplasmic hemoglobin quenched the effective fluorescence yield of fura-2 by a factor of about 100. All red cells were found to fluoresce upon excitation at 380 nm, and the fluorescence intensities they emitted at 510 nm were approximately +/- 20% about the mean intensity, indicating a fairly uniform distribution of incorporated chelator among the cells. Red cells loaded with these high levels of fura-2 retained their biconcave shape, and a comparison between their transmission images at 415 nm and their fura-2 fluorescence images suggests that the concentration of fura-2 was also uniform throughout the cytosol. These results validate assumptions made in earlier experiments with non-fluorescent incorporated Ca2+ chelators, and demonstrate the feasibility of fura-2 and Ca2+ imaging of intact red cells, despite considerable quenching of probe fluorescence by hemoglobin.

Triple therapy of Helicobacter pylori infection in peptic ulcer. A 12-month follow-up study of 93 patients

This study was undertaken to evaluate the success of triple therapy in peptic ulcer patients and ulcer relapses. One hundred and one consecutive Helicobacter pylori-positive peptic ulcer patients were assigned to an open trial with 2 weeks of treatment with colloidal bismuth subcitrate, amoxicillin, and metronidazole. At the 6-week follow-up only 1 duodenal ulcer was unhealed of 57 active ulcers, and H. pylori was found to be eradicated in 84% of the 100 subjects. The sensitivity to metronidazole was determined from 71 pretreatment strains of H. pylori. Eradication of H. pylori succeeded in 89% of the patients with metronidazole-susceptible strains and in 61% of patients with metronidazole-resistant strains (p < 0.03). All 16 patients in whom the treatment failed to eradicate the organism had metronidazole-resistant strains after treatment. The ulcer relapse rate was low. At the 12-month follow-up of 93 patients only 1 of the 84 H. pylori-negative patients (including 4 patients after new successful therapy) had relapsing ulcers (2 asymptomatic episodes), and 1 had H. pylori reinfection, whereas 3 of the 9 bacteria-positive patients relapsed (p = 0.002); at the 2-year control 2 more patients had ulcer relapses. The eradication of H. pylori infection clearly prevents relapses of peptide ulcer, but the success of triple therapy depends on the frequency of pretreatment metronidazole-resistant H. pylori strains.

Distribution of erythrocyte free porphyrin content in erythropoietic protoporphyria

Erythrocytes of patients suffering from erythropoietic protoporphyria (EPP) contain high levels of unchelated protoporphyrin IX (PP) molecules when they enter circulation, and the leakage of PP that leaks from the circulating cells is responsible for the patients' cutaneous photosensitivity. The level of PP in EPP blood has long been used as an indicator of the severity of the disease and is useful in its management. The present study investigates what additional information may be obtained by determining the distribution of the PP content of individual EPP red cells. Absorption and fluorescence images of fields of the dispersed and immobilized red cells from nine patients with EPP were acquired under computer control by use of an inverted fluorescence microscope equipped with a cooled slow-scan charge-coupled device camera. The distribution functions of the fluorescence emitted by individual red blood cells (IRBC) were derived by a suitable image analysis program and were converted to the distributions of the cellular PP content by relating the average value of the distributions (Iav) to the PP level of packed cells, as determined by an extraction assay. The IRBC distributions show that a small percentage of the red cells is responsible for most of the PP fluorescence, and the distributions of IRBC/Iav for the nine patients with EPP were found to be very similar. This is consistent with the leakage rate during circulation being approximately proportional to the cells' PP content.

Cholesterol malabsorption in pancreatic insufficiency: effects of enzyme substitution

Defective lipolysis, steatorrhea, and hypocholesterolemia characterize pancreatic insufficiency. Lipid metabolism in pancreatic insufficiency was studied by measuring serum lipoproteins, cholesterol absorption with double labels and serum plant sterols, and bile acid and cholesterol synthesis with fecal and dietary steroid analysis and cholesterol precursor sterols before and during exogenous pancreatic enzyme substitution. Baseline fecal fat, masses, bile acids and neutral steroids, and cholesterol synthesis were increased, whereas cholesterol absorption was markedly reduced. In fact, the present data suggest that sterol absorption may be disturbed more sensitively than fat absorption in pancreatic insufficiency. Enzyme substitution significantly reduced fecal fat, masses, bile acids and neutral steroids, and synthesis of cholesterol and improved cholesterol absorption in relation to serum cholesterol, although normal values were not obtained. Serum level of high-density lipoprotein cholesterol was significantly elevated by exogenous enzymes, whereas levels of cholesterol or triglycerides in other lipoproteins remained unchanged. Improved sterol absorption increased also serum levels of plant sterols and reduced levels of cholesterol precursors and cholesterol synthesis and precursor sterol-plant sterol ratios. Thus, reduced intestinal lipolysis with expanded oil phase appears to be a major reason for impaired cholesterol absorption, causing enhanced cholesterol and, consequently, bile acid synthesis and reduced serum cholesterol level. Exogenous enzyme substitution seems partly to correct these abnormalities, improvements of which can be monitored by the gas-liquid chromatographic determination of serum plant sterols or cholesterol precursor-plant sterol ratios.

Distribution of non-heme porphyrin content of individual erythrocytes by fluorescence image cytometry and its application to lead poisoning

The quantitation of the non-heme porphyrin content of circulating erythrocytes is an important tool in the screening, diagnosis, and management of lead disease, iron deficiency anemia, and certain porphyrias. Useful information about these pathological conditions may be obtained from the distribution of the non-heme porphyrin content of individual red blood cells. An image-based cytometry system was developed and used to determine the cellular distributions of zinc protoporphyrin (ZPP) in the erythrocytes of normal and lead-exposed human subjects. The fluorescence cytometry system described here lends itself to a wide range of statistical studies of cell populations, in which extrinsic fluorescent probes or antibodies may be used instead of porphyrin. Image-based cytometry appears to offer a number of important advantages over the more conventional flow cytometry systems, including greater sensitivity, applicability to a wider range of cellular parameters, and the ability to retain images of each cell used in the survey for subsequent examination. Pairs of absorption and fluorescence images of many fields of dispersed immobilized red cells were acquired by means of a program which controls the microscope stage, focussing, shutters, filter wheels, and a cooled, slow-scan CCD camera. The observed marked differences in the ZPP distributions of erythrocytes from donors with chronic and acute lead exposure are discussed in terms of the metabolism of internalized lead.

The distribution of cytochrome P-450-mediated drug oxidation and glutathione in periportal and perivenous rat hepatocytes after phenobarbital treatment

The effect of phenobarbital pretreatment on acinar distribution of microsomal drug metabolizing enzymes was investigated by analysis of periportal (pp) and perivenous (pv) enriched rat hepatocytes isolated by collagenase gradient perfusion. In untreated animals the activities of cytochrome P-450, NADPH-cytochrome c reductase and microsomal ethanol oxidation were significantly higher in pv cells. Phenobarbital produced a 45% increase of the yielded microsomes related to the hepatocytic protein but did not change their relative distribution. The content of reduced glutathione (GSH) was lower in hepatocytes from the pv area. The GSH content was more than 20% increased after phenobarbital treatment in both subclasses of cells, but the distribution pattern remained unchanged. The higher activity of drug metabolizing enzymes in the pv area of untreated animals may account for the higher cytotoxicity of numerous drugs to the perivenous hepatocytes. A 3-day treatment with phenobarbital equalized the pp-pv difference by producing more induction of the periportal cytochrome P-450-mediated drug and ethanol oxidation capacities in microsomes derived from periportally enriched hepatocytes.

Comparison of ethanol metabolism in isolated periportal or perivenous hepatocytes: effects of chronic ethanol treatment

Ethanol metabolism in rat hepatocytes isolated either from the periportal (pp) or the perivenous (pv) area by collagenase gradient perfusion was compared to reveal metabolic factors that could be associated with the development of perivenous alcoholic liver damage. Cells were also isolated from rats given ethanol (E) chronically by addition to the drinking fluid. One group (EM) received in addition the alcohol dehydrogenase inhibitor 4-methylpyrazole, which potentiated the ethanol treatment by causing sustained elevated diurnal blood ethanol levels. Fatty degeneration ensued in only one-third of the E rats but in all of the EM rats. The periportal/perivenous activity distributions of alanine aminotransferase (ALAT) and glutamate dehydrogenase (GLDH) were 2.2 and 0.75, respectively. Both ethanol treatments significantly decreased the ALAT and increased the GLDH activities, but did not change their pp/pv distributions. Ethanol treatment also increased ethanol and acetaldehyde oxidation, but to the same extent in pp and pv cells. The increase was more marked in cells from EM rats despite their more severe liver fatty degeneration. Ethanol incubation also increased the lactate/pyruvate ratio to the same extent in pp and pv cells both from control or ethanol-treated rats. Our results indicate that periportal and perivenous hepatocytes convert ethanol via acetaldehyde to acetate equally well and with similar effects even after chronic ethanol treatment. Consequently, preferential damage of the perivenous area after chronic ethanol intake is not caused by inherent or acquired differences in ethanol metabolism between perivenous and periportal hepatocytes. Rather, sinusoidal gradients only established in the intact liver may exaggerate the metabolic imbalance by ethanol in the perivenous area, thus explaining its greater vulnerability to damage by alcohol abuse.

The effect of chronic ethanol ingestion on ethanol metabolizing enzymes in isolated periportal and perivenous rat hepatocytes

Periportal (pp) and perivenous (pv) hepatocyte populations were separated using a two-directional closed perfusion technique with selective addition of collagenase either to direct or retrograde perfusions (Väänänen, H. et al., Liver 1983; 3:131). The activity of GPT in hepatocytes from the pp-area was 1.9 times higher than in cells from the pv-area (p less than 0.01). The distribution of glutamate dehydrogenase and pyruvate kinase activities was reversed; pp/pv ratios of 0.7 and 0.5, respectively, were observed (p less than 0.001, p less than 0.05). Chronic ethanol consumption for 12 weeks (mean daily ethanol intake 11.4 gm per body weight corresponding to 29% of total energy intake) did not cause histological changes but decreased GPT activity, increased glutamate dehydrogenase and pyruvate kinase activities and did not alter their pp/pv distribution. Alcohol dehydrogenase and aldehyde dehydrogenase activities were evenly distributed in pp- and pv-hepatocytes. Chronic ethanol treatment slightly decreased alcohol dehydrogenase activity (p less than 0.05) and increased the activity of low Km aldehyde dehydrogenase (p less than 0.001, p less than 0.05). The specific activity of NADPH-dependent microsomal ethanol oxidation was 50% higher in pv-hepatocytes (p less than 0.05). Chronic ethanol treatment did not increase the specific activity of microsomal ethanol oxidation but reduced the pp-pv activity difference. The results indicate that the enzymatic capacity to oxidize ethanol is evenly distributed in the acinus and that, after long-term moderate ethanol treatment, despite lack of parenchymal lesions, changes in the activity of enzymes involved in ethanol metabolism are observed.(ABSTRACT TRUNCATED AT 250 WORDS)

A simple procedure using 4-methylpyrazole for developing tolerance and other chronic alcohol effects

Young rats given ethanol chronically by gradually increasing the concentration in the drinking fluid to 17.5% reached a maximal daily consumption of 15-17 g ethanol/kg body wt., which corresponded to 35-40% of their energy intake. This chronic treatment was markedly potentiated by additional supplementation of the drinking fluid with a low dose of the alcohol dehydrogenase inhibitor 4-methylpyrazole. Rats on this regimen exhibited higher and more sustained blood ethanol levels. Consequently, more pronounced functional and metabolic tolerance developed and more frequent signs of physical dependence was observed than in rats drinking only ethanol solution. Simple provision of drinking fluid supplemented with ethanol and 4-methylpyrazole appears to provide a nutritionally adequate and easy way to produce tolerance and other chronic alcohol effects.

Uninterrupted prolonged ethanol oxidation as a main pathogenetic factor of alcoholic liver damage: evidence from a new liquid diet animal model

Marked fatty infiltration and degenerative or mild inflammatory changes including eosinophilic cytoplasmic degeneration in centrilobular cells and focal inflammatory changes with cell necrosis were observed in livers of rats maintained for 12 weeks on a nutritionally adequate and balanced liquid ethanol diet. The animals continuously oxidized ethanol due to the supplementation of the diet with a low dose of 4-methylpyrazole (4-MP, an alcohol dehydrogenase inhibitor), that decreased ethanol elimination by about 20%. In other, equicalorically pair-fed groups of rats receiving (a) a similar ethanol-containing liquid diet without 4-MP or (b) a diet with 4-MP and 20% less ethanol, only a few minor changes were seen. The liver histology of rats pair-fed a control diet with a 4 times higher doses of 4-MP was completely normal. The results indicate that the prolonged imbalance of hepatic metabolism due to the uninterrupted oxidation of ethanol is a crucial factor in the development of alcoholic liver injury.

Qualitative study on the Kupffer cells in the liver of ethanol- and carbon tetrachloride-treated rats

The treatment of rats with ethanol or CCl4 caused in addition to an increase in numbers, qualitative changes in the Kupffer cells. The rate of phagocytosis of opsonized erythrocytes was greatly increased in the Kupffer cells from CCl4-treated rats, compared with a slightly decreased phagocytosis in similar cells taken from ethanol-treated rats. The number of Fc-receptors per cell was slightly higher in the Kuppffer cells from ethanol- and CCl4-treated rats than in normal rats. Although the nonparenchymal cell fraction from the livers of ethanol- and CCl4-treated rats contained more mononuclear phagocytes than the respective control samples, both the adhering and nonadhering subfractions from the livers of ethanol-treated rats contained proportionally fewer mononuclear phagocytes following an assessment of adhesiveness than the other samples. No difference in esterase staining was observed between the groups.

Effects of ethanol on liver regeneration after partial hepatectomy in rats

The effect of ethanol on hepatic regeneration after partial hepatectomy was studied. Ethanol was administered in a nutritionally adequate liquid diet 4 times daily by gastric intubation. The dose of ethanol was selected to maintain a continuous level of ethanol in the animals throughout the experiment. Treatment was started 24 hours before the operation and continued for 6 days. Control animals were pair-fed on a diet in which ethanol was isocalorically replaced by carbohydrate. On the 1st, 2nd, 3rd and 5th day after the operation the incorporation of [3H]-labelled thymidine into liver DNA and [14C]-labelled leucine into liver proteins and the mitotic index of the regenerating liver was assessed. On the 2nd and 3rd day the incorporation of labelled thymidine into DNA in the regenerating livers of alcohol-fed animals was significantly (P less than 0.05) lower than in pair-fed controls. The inhibition was most pronounced (60%) on the 2nd day after the operation. This was associated with a significant (P less than 0.01) decrease in mitotic activity, which was most pronounced in the periportal area. At the end of the experiment, however, DNA content was similar both in ethanol-treated and in control livers. It is concluded that the continuous presence of ethanol retards DNA synthesis and cell division of regenerating rat liver after partial hepatectomy. The incorporation of [14C]-leucine into liver proteins was inhibited by ethanol on the second day of regeneration (P less than 0.01), and at the end of the experiment the livers of ethanol-fed rats contained more protein than the control livers. This accumulation of proteins was accompanied by hepatomegaly.

Inhibition of the synthesis of macromolecules by ethanol in regenerating rat liver

The effects of ethanol on DNA and protein synthesis of regenerating rat liver has been studied. A single dose of ethanol, when given either before, at the time or 1 h after the partial hepatectomy significantly inhibited the accelerated synthesis of ornithine decarboxylase protein which was used as a marker of protein synthesis. Ethanol seemed to inhibit the synthesis of ornithine decarboxylase at transcriptional level of protein synthesis and the inhibition appeared to be directly due to the presence of ethanol molecules. When rats were chronically fed with ethanol-containing liquid diet also the total protein synthesis was inhibited during the two first days of regeneration. In this experiment also the rate of DNA synthesis was greatly inhibited by ethanol treatment. The results show that the ethanol-induced inhibition of the synthesis of tissue macromolecules is ideally demonstrated in regenerating rat liver. Furthermore they suggest that this effect may be of importance in the progression of alcoholic liver injury.