Search PubMed⌕ Search

Biomedical subjects

A Bini

Publications and source records attributed to A Bini.

At least 55 records · Page 3Linked to original sources
PubMed1995

Effect of S-adenosyl-L-methionine on ethanol cholestasis and hepatotoxicity in isolated perfused rat liver.

We investigated whether S-adenosyl-L-methionine (SAMe) influences the inhibitory effect of ethanol on bile secretion and ethanol hepatotoxicity in the isolated perfused rat liver. SAMe (25 mg/kg intramuscularly three times a day) was administered for three days consecutively. Liver was then isolated and perfused with taurocholate to stabilize bile secretion and exposed to 1% ethanol for 70 min. The effect of ethanol on bile flow, bile salt biliary secretion, oxygen liver consumption, AST and LDH release in the perfusate, and hepatic concentration of glutathione, malondialdehyde, and diene conjugates was compared between SAMe-treated livers (N = 11) and paired controls (N = 11). Control experiments without ethanol were also performed (N = 6). Exposure to 1% ethanol induced a significantly (P < 0.03) higher inhibition of bile flow (-35% vs 17%) and bile salt secretion (-28% vs 16%) in untreated compared with SAMe-treated livers. During 1% ethanol exposure, the release of LDH and AST in the perfusate was significantly lower (P < 0.02) in SAMe-treated livers. Oxygen liver consumption was markedly inhibited by 1% ethanol administration (P < 0.02 vs controls without ethanol), an effect almost totally prevented by SAMe treatment (P < 0.02 vs ethanol controls). The hepatic concentration of total glutathione was significantly (P < 0.02) decreased by 1% ethanol exposure, but this effect was less pronounced in SAMe-treated than in untreated controls (P < 0.02). The hepatic levels of malondialdehyde and diene conjugates were not significantly changed by ethanol exposure in either SAMe-treated or control livers in comparison to ethanol-free controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Mortality among drug users in the AIDS era.

BACKGROUND: Infection with human immunodeficiency virus type 1 (HIV-1) causes progressive immune deficiency, the acquired immunodeficiency syndrome (AIDS), and death. Mortality, however, particularly with causes other than AIDS, deserves further study. A retrospective cohort study among drug users in Italy was performed to estimated absolute and proportional mortality rates due to AIDS and other causes, with or without HIV-1 infection. METHODS: All subjects who enrolled between January 1980 and July 1990 in the drug treatment programme in the Province of Bologna, Italy, were included in the cohort. Each subject was categorized for HIV-1 antibody status (positive, negative, untested), vital status (in 1990 by national surveillance), and causes of death (by death certificate). Data were analysed with actuarial and time-dependent covariate methods. RESULTS: There were 332 deaths among 4962 drug users who were followed for 21,130 person-years. This mortality rate (1.57 per 100 person-years) was increased 18-fold compared to the general population. Actuarial 10-year mortality estimates were 28.2% for the 2040 HIV-1 positive subjects, 12.1% for the 1859 HIV-1 untested subjects, and 2.5% for the 1063 HIV-1 negative subjects. AIDS contributed to 150 deaths, followed by drug overdose (64 deaths) and trauma (39 deaths). Compared to others in the cohort, mortality with AIDS and non-AIDS causes was reduced for HIV-1 negative subjects. In contrast, mortality for HIV-1 positive subjects was increased with AIDS, trauma, overdose, various bacterial infections, hepatitis, and cirrhosis. CONCLUSIONS: Mortality with HIV-1 infection was associated not only with opportunistic infections and malignancies but also with competing causes of death, particularly hepatic disease. Further investigation is needed to clarify whether alcohol, analgesics, hepatitis viruses, or other agents have enhanced hepatotoxicity for HIV-1 infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Effect of glucagon on intracellular pH regulation in isolated rat hepatocyte couplets.

To elucidate mechanisms of glucagon-induced bicarbonate-rich choleresis, we investigated the effect of glucagon on ion transport processes involved in the regulation of intracellular pH (pHi) in isolated rat hepatocyte couplets. It was found that glucagon (200 nM), without influencing resting pHi, significantly stimulates the Cl-/HCO3- exchange activity. The effect of glucagon was associated with a sevenfold increase in cAMP levels in rat hepatocytes. The activity of the Cl-/HCO3- exchanger was also stimulated by DBcAMP + forskolin. The effect of glucagon on the Cl-/HCO3- exchange was individually blocked by two specific and selective inhibitors of protein kinase A, Rp-cAMPs (10 microM) and H-89 (30 microM), the latter having no influence on the glucagon-induced cAMP accumulation in isolated rat hepatocytes. The Cl- channel blocker, NPPB (10 microM), showed no effect on either the basal or the glucagon-stimulated Cl-/HCO3 exchange. In contrast, the protein kinase C agonist, PMA (10 microM), completely blocked the glucagon stimulation of the Cl-/HCO3- exchange; however, this effect was achieved through a significant inhibition of the glucagon-stimulated cAMP accumulation in rat hepatocytes. Colchicine pretreatment inhibited the basal as well as the glucagon-stimulated Cl-/HCO3- exchange activity. The Na+/H+ exchanger was unaffected by glucagon either at basal pHi or at acid pHi values. In contrast, glucagon, at basal pHi, stimulated the Na(+)-HCO3- symport. The main findings of this study indicate that glucagon, through the cAMP-dependent protein kinase A pathway, stimulates the activity of the Cl-/HCO3- exchanger in isolated rat hepatocyte couplets, a mechanism which could account for the in vivo induced bicarbonate-rich choleresis.

Animals↗
PubMed1995

Functional and ultrastructural features of ethanol/bile salts interaction in the isolated perfused rat liver.

We investigated whether bile salts (BS) with different hydrophobic-hydrophilic properties interact with ethanol on bile secretion, enzyme (aspartate transaminase [AST], lactate dehydrogenase [LDH]) release in the perfusate, liver ultrastructure, and vesicular exocytosis in the isolated perfused rat liver. Ethanol (0.1 or 1%) promoted a rapid decrease of bile flow and BS secretion in livers perfused with taurocholate (TCA), the physiologic BS in the rat (-28% decrease of baseline values with 0.1% and -34% with 1% ethanol). The inhibitory effect of ethanol on bile flow and BS secretion was significantly (P < .02) attenuated by perfusing liver with the hydrophilic BS, tauroursodeoxycholate (TUDCA), and it was exacerbated (P < .02) by perfusion with the hydrophobic BS, taurodeoxycholate (TDCA). The release of AST and LDH in the perfusate was unaffected by 0.1% ethanol, but increased threefold to fivefold by 1% ethanol in TCA-perfused livers. This cytolitic effect of ethanol was not observed in TUDCA-perfused livers, but it was enhanced (P < .03) by perfusion with TDCA. No ultrastructural abnormalities were found in either TCA- or TUDCA-perfused livers, with or without 1% ethanol. Only minimal changes were found in livers perfused with TDCA alone, but, in the presence of TDCA, 1% ethanol induces marked mitochondrial damage. The biliary excretion of the fluid phase marker horseradish peroxidase was inhibited by ethanol, an effect reversed by TUDCA (P < .02) and exacerbated by TDCA (P < .04). In conclusion, this study demonstrates that hydrophilic BS such as TUDCA counteract the inhibitory effect of ethanol on bile secretion and vesicular exocytosis as well as the ethanol-induced cytolitic effect in the isolated perfused rat liver. In the presence of hydrophobic BS such as TDCA, the exposure to ethanol promotes a marked inhibition of bile secretion and vesicular exocytosis as well as prominent mitochondrial damage.

Animals↗
PubMed1995

Effect of Brefeldin A on transcytotic vesicular pathway and bile secretion: a study on the isolated perfused rat liver and isolated rat hepatocyte couplets.

This study investigated the effect of Brefeldin A (BFA) on the transcytotic vesicular pathway labeled with horseradish peroxidase (HRP) in both isolated rat hepatocyte couplets (IRHC) and the isolated perfused rat liver (IPRL). To evaluate the role of the transcytotic vesicular pathway on bile secretion, the effect of BFA on bile secretion in the IPRL was then investigated. In the basolateral area of IRHC, BFA showed no effect on the density and percentage of area of HRP-labeled vesicles. However, HRP-labeled vesicles tended to accumulate in the juxtanuclear area of BFA-treated hepatocytes (P < .001 vs. controls). In the pericanalicular area, on the other hand, HRP-labeled vesicles were depleted compared with controls (P < .001). In keeping with these findings, although the early peak remained unchanged, BFA inhibited as much as 50% of the late peak of HRP excretion in bile, after a pulse load of HRP in the IPRL. Bile flow and the biliary secretion of bile salts (BS) and phospholipids were not modified by BFA in isolated livers perfused without BS in the perfusate or with 1 mumol/min taurocholate (TCA). In BFA-treated livers, peak bile flow and BS output decreased by 20% (P < .05 vs. controls) only when a 5 mumol TCA bolus was administered. In conclusion, this study demonstrates that BFA inhibits the transcytotic vesicular pathway in the liver. However, BFA has no significant effect on bile secretion either in basal conditions or during perfusion with physiological amounts of BS. BFA slightly decreases bile flow and BS output only after an overload of BS, providing evidence against the physiological relevance of the transcytotic vesicular pathway in the process of bile formation.

Animals↗
PubMed1995

Recombinant interferon-alpha and ursodeoxycholic acid versus interferon-alpha alone in the treatment of chronic hepatitis C: a randomized clinical trial with long-term follow-up.

OBJECTIVES: The purpose of this study was to compare, within a randomized controlled trial, the efficacy of recombinant interferon-alpha in combination with ursodeoxycholic acid versus interferon-alpha alone in the treatment of chronic HCV hepatitis. METHODS: Forty anti-HCV positive chronic hepatitis patients with ALT levels persistently greater than 3 times the upper normal level were randomized to receive either interferon-alpha (6 million units three times/wk for 6 months) plus ursodeoxycholic acid (10 mg/kg/day for 9 months) (n = 20) or interferon-alpha (6 million units three times/wk for 6 months) alone (n = 20). Disease activity was monitored monthly by ALT measurement until 18 months after interferon-alpha cessation. Serum HCV-RNA was measured at baseline and after 6, 9, and 24 months. Liver biopsies (basal and at the 9th month) were evaluated blindly and scored by Knodell's criteria. RESULTS: The probability of full or partial response during interferon-alpha treatment was similar in the two groups. The probability of biochemical relapse (i.e, any persistent return of ALT above normal) after 18-month of posttreatment follow-up was 75% in both the combination and the monotherapy group. Relapse, however, occurred significantly later in the combination than in the monotherapy group (6.6 +/- 5.4 [SD] months and 1.8 +/- 1.6 months after IFN-alpha cessation, respectively, p < 0.02). Severe biochemical relapse (i.e., a persistent ALT elevation greater than 3 times normal) occurred more frequently and earlier (p = 0.05) in patients treated with interferon-alpha (58.3%) than in those receiving the combination therapy (27.3%). The cumulative duration of normalized ALT periods during and after treatment was significantly greater (p = 0.005, chi 2) in patients treated with IFN-alpha + UDCA than with monotherapy (189/354 months vs 136/323 months. Lobular necrosis improved in both groups (p = 0.056 and p = 0.001, respectively), whereas portal inflammation improved (p = 0.009) only in the combination therapy group. Among the 30 patients who were viremic at entry, plasma HCV-RNA was no longer detectable after 6 months in four from the combination group and in five from the monotherapy group, yet all patients but one returned HCV-RNA positive 3 months after interferon-alpha cessation and were still viremic after 18 months. Cox's multiple regression identified the histological degree of posttreatment portal inflammation as the sole positive indicator of relapse. CONCLUSIONS: The combination of interferon-alpha and ursodeoxycholic acid prolongs the efficacy of interferon-alpha alone in chronic hepatitic C by delaying the probability of biochemical relapse and/or by reducing its severity, without affecting HCV viremia.

Adult↗
PubMed1994

Flow and antibody binding properties of hydrated fibrins prepared from plasma, platelet rich plasma and whole blood.

Previous studies, using cross-linked fibrin prepared from purified fibrinogen, showed low binding of a fibrin-specific monoclonal antibody designated T2G1 (Procyk et al., Blood 77:1469-75, 1991). In this study we investigated the binding of T2G1 and one other antibody to clots prepared from platelet poor plasma (PPP), platelet rich plasma (PRP) and whole blood. In contrast to our previous study, we used unlabelled antibodies and quantitated the level bound by ELISA, measuring antibody concentration in the non-adsorbed fraction. Antibody T2G1 bound 1.35 +/- 0.10 pmol/pmol fibrin (n = 11) to whole blood columns, 1.64 +/- 0.18 (n = 10) to PRP columns and 1.58 +/- 0.13 (n = 8) to PPP columns. The binding of T2G1 to columns made from purified fibrinogen was 0.78 +/- 0.05 pmol/pmol fibrin (n = 15). An antibody to a conformation-dependent epitope on Fragment D (Fd4-7B3) bound in comparable amounts to the different fibrins. Flow data show that whole blood columns, and also, but to a lesser extent those made with plasma, had a higher flow rate, permeability and fiber mass-length ratio than columns prepared from fibrinogen indicating a more coarse fibrin network. These data show that the presence of other proteins and blood cells, similar to what might occur in vivo, not only lead to an increase in the permeability of gels but also allow for better exposure of some epitopes.

Antibodies, Monoclonal↗
PubMed1993

In vivo total body water assessment by total body electrical conductivity in rats suffering perturbations of water compartment equilibrium.

Total body electrical conductivity (TOBEC) is a simple and non-invasive method for the assessment of body composition in vivo. Information regarding the applicability of TOBEC in the condition of abnormal fluid balance is scarce. In the present paper we give the results of the comparison between TOBEC and total body water (TBW; assessed by the tritium dilution technique) in three groups of animals: (1) healthy (n 17), (2) expanded fluid volume by secondary biliary cirrhosis (SBC; n 9) and (3) Furosemide-treated rats (n 9). The TOBEC score and TBW by tritium dilution were found to be highly correlated in the pooled sample (r 0.90) and in normal (r 0.87), SBC (r 0.73) and Furosemide-treated (r 0.89) rats. However, the relationship between TOBEC and TBW, described by least-squares regression analysis, was found to be similar for SBC and normal rats but was significantly different for Furosemide-treated and normal rats. These findings suggest that TOBEC is unable to track TBW accurately when the ratio between intracellular and extracellular water is chronically or acutely altered.

Animals↗
PubMed1993

Tert-butylhydroperoxide bioactivation to methyl radical in rat liver mitochondria and submitochondrial particles.

Electron paramagnetic resonance spectroscopy (EPR) coupled to the spin trapping technique was used to detect carbon-centered radicals in rat liver mitochondria and submitochondrial particles exposed to t-butyl-hydroperoxide (TBH), using the spin trapping agent 3,5-dibromo-4-nitroso-benzenesulfonic acid (DBNBS). The signal recorded was unambiguously assigned to the methyl radical adduct. DBNBS was added to isolated rat liver mitochondria energized with succinate, and the methyl radical adduct was observed. The addition of NADH, NADPH, inhibitors of the respiratory chain, and of monoaminoxidase (MAO) inhibitors did not cause any relevant modification in the yield of radical adduct formation. Boiling and the addition of a non-ionic detergent inhibited the formation of the radical adduct, while experiments carried out under hypoxic conditions generated a significant increase in methyl radical formation. Further experiments were carried out on sub-mitochondrial particles (SMP) giving rise to, basically, the same results. From the above results, we are proposing that haem prosthetic groups are the likely source of TBH bioactivation in mitochondria.

Animals↗
PubMed1993

[Left ventricular free wall rupture during a myocardial infarct: its incidence, clinical presentation, evolution].

Of 554 patients hospitalized for acute myocardial infarction, 61 (11%) died in the Intensive Care Unit. Echocardiography (performed at admission, at discharge and in every case of modification of the clinical course) allowed the diagnosis of left ventricular free wall rupture (RPLVS) in 20. The clinical course was acute in 13 of the latter, presenting with electromechanical dissociation (DEM). Pericardiocentesis allowed survival of one patient of this group. In 6 patients RPLVS had a subacute pattern, with progressive hypotension (in 2 cases preceded by syncope): pericardiocentesis allowed temporary stabilization of 4 patients; 2 had surgical repair with 1 long-term survivor. In 1 patient RPLVS began with lipothymia, and then he stabilised spontaneously. Many physiopathological mechanisms are discussed which could explain the great clinical variability of RPLVS. Awareness that RPLVS can appear with patterns different from DEM is fundamental for the diagnosis of subacute RPLVS. Indeed, this form of RPLVS, when recognized, can be treated with an encouraging prognosis.

Aged↗
PubMed1992

Low molecular weight fibrinogen degradation products stimulate the release of growth factors from endothelial cells.

Cultured porcine aortic endothelial cells (PAEC) constitutively produce and secrete in their culture medium mitogens collectively called endothelial cell-derived growth factors (EDGFs). Incubation of PAEC with fibrinogen-degradation products (FDPs) obtained by plasmin digestion of highly purified fibrinogen caused an increased release of EDGFs, as assessed by [3H]-thymidine incorporation in 3T3 mouse fibroblasts. The effect was time-dependent and correlated with the degree of fibrinogenolysis. It was accompanied by elongation of the cells. Neither increase in EDGFs release nor cell damage was observed when non-degraded fibrinogen was incubated with endothelial cells. Low molecular weight fibrinogen degradation products (LMWFDPs) (M(r) less than or equal to 10,000), and the higher molecular weight fibrinogen fragments D and E were tested under the same conditions. Only the LMWFDPs caused elongation and damage to PAEC and a marked stimulation (up to 12 fold) of EDGFs release. A low density growth assay revealed that the released EDGFs were mitogenically active on the same PAEC. The activity of the released EDGFs was time and dose dependent on both 3T3 fibroblasts and PAEC, indicating that LMWFDPs caused enhanced release of EDGFs that can act in paracrine and autocrine fashion. This study suggests an additional role for fibrinogenolysis contributing to wound healing, and possibly to atherosclerosis.

Animals↗
PubMed1992

Activation of cholinergic tone by pyridostigmine reverses the inhibitory effect of corticotropin-releasing hormone on the growth hormone-releasing hormone-induced growth hormone secretion.

Previous studies have shown that corticotropin-releasing hormone (CRH) is capable of inhibiting growth hormone (GH) secretion in response to GH-releasing hormone (GHRH). In an attempt to clarify the mechanism of the CRH action, we have studied the effect of enhanced cholinergic tone induced by pyridostigmine on the CRH inhibition of the GH response to GHRH in a group of six normal men and six normal women. All subjects presented a normal GH response to 50 micrograms i.v. GHRH administration (mean peak +/- SEM plasma GH levels 20 +/- 2.9 micrograms/l in men and 28.9 +/- 2.9 micrograms/l in women) with a further significant increase after pyridostigmine pretreatment (60 mg orally given 60 min before GHRH) in men (GH peaks 43.1 +/- 6.9 micrograms/l, p less than 0.005) but not in women (GH peaks 39.2 +/- 3.0 micrograms/l). In the same subjects, peripherally injected CRH (100 micrograms) significantly inhibited the GH response to GHRH (GH peaks 8.1 +/- 0.6 micrograms/l in men, p less than 0.005 and 9.9 +/- 0.7 micrograms/l in women, p less than 0.005). Pyridostigmine (60 mg) given orally at the same time of CRH administration (60 min before GHRH) reversed the CRH inhibition of GHRH-induced GH secretion (GH peaks 35.3 +/- 8.2 micrograms/l in men and 35 +/- 3.3 micrograms/l in women) with a response not significantly different to that seen in the pyridostigmine plus GHRH test. Our data confirm that pyridostigmine is capable of potentiating the GHRH-induced GH release in normal male but not female subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Rupture of the free wall of the left ventricle as the first manifestation of a myocardial infarct. A clinical case operated on with success].

A case of an undetected myocardial infarction in a patient with diabetes mellitus in which the first clinical sign was a syncope due to rupture of the left ventricular inferior wall is described. Survival was enhanced by a fast diagnosis (aided by the availability of an ECO 2D in the emergency room), by emergency pericardiocentesis with temporary haemodynamic stabilization and by prompt access to the Cardiosurgical Unit. A prompt diagnosis and treatment can allow the survival of patients, even in the extreme case that the ventricular wall rupture represents the first clinical manifestation of the myocardial infarction. The left ventricular free wall rupture in the course of myocardial infarction has a subacute pattern in about 30%, due to various mechanisms such as thrombosis or pericardial adherence over the ruptured wall.

Coronary Angiography↗