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Biomedical subjects

C Gaudin

Publications and source records attributed to C Gaudin.

At least 55 records · Page 3Linked to original sources
PubMed1994

Hemodynamic responses to selective blockade of beta 2- and beta 1-adrenoceptors in conscious rats with cirrhosis.

This study examined the hemodynamic effects of selective beta 2-adrenergic blockade (ICI 118,551, 100 micrograms/kg intravenous (i.v.)), selective beta 1-blockade (atenolol, 2 mg i.v.) and nonselective beta-blockade (propranolol, 2 mg i.v.) in conscious rats with cirrhosis. Pressure and blood flow measurements (radioactive microsphere method) were performed before and following drug administration. ICI 118,551 significantly decreased portal tributary blood flow (21%), portal pressure (4%) and cardiac index (12%). Portal tributary blood flow decreases were significantly more marked than changes in cardiac index. Atenolol significantly decreased portal tributary blood flow (27%), portal pressure (15%), cardiac index (17%) and arterial pressure (7%). Propranolol significantly decreased portal tributary blood flow (37%), portal pressure (17%), cardiac index (30%), and arterial pressure (9%). Portal tributary blood flow decreases due to ICI 118,551, but not those due to atenolol, were significantly less marked than the decreases caused by propranolol. ICI 118,551- and atenolol-induced cardiac index decreases were significantly less marked than propranolol-induced decreases. In conclusion, in rats with cirrhosis, selective beta 2-blockade reduces portal pressure and portal tributary blood flow mainly by a direct effect on splanchnic vessels. This portal hypotensive action, however, was slight. Propranolol decreases portal tributary blood flow by the combination, but not the summation, of its beta 1- and beta 2-blocking effects.

Adrenergic beta-Antagonists↗
PubMed1994

Cytofluorometric analysis of chondrotoxicity of fluoroquinolone antimicrobial agents.

To better understand quinolone-related arthropathy, we conceived an experimental ex vivo model using cell cultures of articular chondrocytes issued from pretreated New Zealand White rabbits (NZW). Juvenile (4- to 5-week-old) NZW were orally dosed with ofloxacin or pefloxacin (300 mg/kg of body weight for 1 day) or with pefloxacin (300 mg/kg for 7 days). Adult (5-month-old) NZW were treated with pefloxacin (300 mg/kg for 1 day). Chondrocytes were enzymatically recovered from cartilage and were analyzed by cytofluorometry using 2',7'-dichlorofluorescein diacetate (DCFH-DA) and dihydrorhodamine 123 (DHR), reflecting cellular respiratory-burst activity, and rhodamine 123 (Rh123) and 10-N-nonyl-acridine orange (NAO), specific for the mitochondrial activity and mass, respectively. A significant increase in the respiratory burst was detected by DCFH-DA and DHR in all treated groups of young animals, compared with untreated control groups. No significant increase of respiratory burst was noted in older treated rabbits. The 7-day treatment resulted in a decrease in mitochondrial uptake of Rh123 and an increase in NAO uptake. Fluoroquinolone arthrotoxicity seems to involve in its early phase the respiratory burst of immature articular chondrocytes.

Animals↗
PubMed1994

[Relationships between plasma concentrations of endothelin and the severity of liver cirrhosis].

OBJECTIVES: Results of studies on plasma endothelin concentrations in patients with cirrhosis are conflicting. Moreover, the relationships between plasma endothelin concentrations and the severity of cirrhosis have not yet been studied. The aim of this study was to measure plasma endothelin concentrations in controls and in patients with cirrhosis. In addition, this study examined the relationships between plasma endothelin concentrations, and the severity of liver disease, splanchnic and systemic hemodynamics. METHODS: Plasma endothelin concentrations (in the hepatic vein and the right atria), hepatic venous pressures, arterial pressure, cardiac output, pulmonary pressures and plasma concentrations of sodium and creatinine were measured in 7 controls and 28 patients with cirrhosis. RESULTS: Plasma endothelin concentrations in the hepatic vein and the right atria were significantly higher in patients with cirrhosis (18.9 +/- 2.9 and 20.2 +/- 3.1 pg/mL, respectively) than in controls (6.1 +/- 1.1 and 7.2 +/- 1.1 pg/mL, respectively). In these patients, hepatic venous plasma endothelin concentrations were significantly correlated with Pugh's score (r = 0.49), hepatic venous pressure gradient (r = -0.44), and plasma sodium concentrations (r = -0.46). No significant correlation was found between plasma endothelin concentrations and systemic hemodynamics. CONCLUSION: Plasma endothelin concentrations are increased in patients with cirrhosis. Moreover, this increase is more marked in patients with severe liver disease than in patients with no or moderate impairment of liver function.

Blood Chemical Analysis↗
PubMed1993

Purification and characterization of endoglucanase C from Clostridium cellulolyticum. Catalytic comparison with endoglucanase A.

An Escherichia coli clone was constructed to overproduce endoglucanase C (CelCCC) from Clostridium cellulolyticum. This construction made it easier to isolate the enzyme but, as observed in the case of endoglucanase A (CelCCA) from the same organism, the purification led to the isolation of two forms of the cellulase differing in their molecular masses, 48 kDa and 41 kDa. N-terminal sequence analysis of both purified enzymes showed that the shorter form was probably the result of partial proteolysis near the COOH-extremity. The difference in mass indicated that the shorter protein lacks the C-terminal reiterated domains (20-24-amino-acid twice-repeated sequences). These particular domains are characteristic of clostridial cellulases acting on cellulose by the mean of cellulosomal particles. Biochemical and enzymic studies were performed on each form of CelCCC, and revealed that their temperature and pH optima were identical, but their catalytic parameters were quite different. Furthermore, the differences of enzymic behavior observed between the two forms of CelCCC are almost identical to those already noted in the case of the two forms of CelCCA. The stereoselectivity of the reaction catalysed by CelCCC and CelCCA was determined using proton NMR spectroscopy; CelCCC acts by configuration inversion, whereas CelCCA acts by configuration retention. The degradation patterns on cellodextrins (ranging from cellotriose to cellohexaose) and chromophoric cellodextrins (from p-nitrophenyl-cellobiose to p-nitrophenyl-cellopentaose) were also investigated in both forms of CelCCC and CelCCA. It emerged that the natural cellodextrins degradation patterns of CelCCC and CelCCA were very similar but the utilization of p-nitrophenyl-cellodextrins showed the existence of considerable differences between these two endoglucanases in terms of cleavage-site position and catalytic parameters. CelCCC and CelCCA were found not to act synergistically on the tested substrates.

Base Sequence↗
PubMed1993

Crystallization and preliminary X-ray analysis of the catalytic domain of endoglucanase from Clostridium cellulolyticum.

The catalytic domain of an endoglucanase belonging to family A (CelCCA) from an anaerobic bacterium (Clostridium cellulolyticum) has been crystallized in a form suitable for X-ray diffraction analysis. The crystals have been grown in the presence of polyethylene glycol 4000 using the vapour diffusion technique. The crystals, which diffract to 2.0 A resolution, belong to the orthorhombic space group P2(1)2(1)2(1) and have the following cell constants: a = 52.4 A, b = 76.2 A and c = 113.5 A.

Amino Acid Sequence↗
PubMed1993

Early colchicine administration reduces hepatic fibrosis and portal hypertension in rats with bile duct ligation.

Chronic administration of colchicine has been suggested as a potential treatment for hepatic fibrosis. The purpose of this study was to examine the effects of chronic oral administration of colchicine on the histological and hemodynamic abnormalities of bile duct ligation in the rat. Forty-eight rats with ligation-section of the common bile duct were randomly and blindly assigned to receive either colchicine (50 mu/kg day) or placebo by gavage for 4 weeks. At the end of the treatment period, morphometric analysis showed that hepatocyte and sinusoidal volume fractions were significantly higher in rats treated with colchicine than in rats receiving placebo (42.4 +/- 1.3 vs. 32.1 +/- 2.6% (mean +/- S.E.) and 8.3 +/- 0.6 vs 4.7 +/- 0.4%, respectively), while bile duct volume fractions (reflecting bile ductular proliferation) and connective tissue fractions were significantly lower in rats treated with colchicine than in rats receiving placebo (12.1 +/- 0.9 vs. 17.0 +/- 0.1% and 37.2 +/- 0.9 vs. 46.1 +/- 2.0%, respectively). Portal pressure (13.4 +/- 0.7 vs. 17.8 +/- 0.5 mmHg), portal tributary blood flow (5.8 +/- 0.4 vs. 8.7 +/- 0.5 ml.min-1.100 g-1) and cardiac index (40.8 +/- 2.3 vs. 50.6 +/- 1.5 ml.min-1.100 g-1) were significantly lower in colchicine-treated rats than in placebo treated animals. In conclusion, in rats with bile duct ligation, colchicine limits the severity of liver lesions and, consequently, of portal hypertension and hyperkinetic syndrome.

Administration, Oral↗
PubMed1993

Reduced splanchnic vasoconstriction to angiotensin II in conscious rats with biliary cirrhosis.

Decreased pressor reactivity to angiotensin II has been demonstrated in portal hypertension due to cirrhosis. The present study investigated the respective roles of portal hypertension and cirrhosis and the hemodynamic mechanisms of the depressor response in different models of portal hypertension in conscious rats. Dose-pressor curves were studied in sham-operated, portal vein stenosed (portal hypertension without cirrhosis) and biliary cirrhotic rats following angiotensin II administration. Decreased pressor response was observed in cirrhotic rats but not in portal vein stenosed rats. The hemodynamic effects of angiotensin II administration (11 ng.100 g-1 body wt.min-1, i.v.) were studied in conscious sham-operated and biliary cirrhotic rats (radioactive microsphere method). The percentage of change from basal values following angiotensin II administration were significantly more marked in sham-operated rats than in cirrhotic rats for mean arterial pressure (+34 vs. +6%), cardiac index (-36 vs. -22%), systemic vascular resistance (+117 vs. +40%). After angiotensin II, portal tributary and hepatic artery blood flows significantly decreased in sham-operated rats (-31 and -14%, respectively) but not in cirrhotic rats (+1 and +23%), whereas changes in renal blood flow were not significantly different between the two groups (-44 vs. -34%). In conclusion, in biliary cirrhotic rats, decreased pressor response to angiotensin II depends on the presence of liver disease rather than on portal hypertension or basal hemodynamic alterations. It also depends on the decreased vasoconstrictive effect which predominates in the splanchnic vascular bed.

Angiotensin II↗
PubMed1993

Renal hemodynamics in patients with cirrhosis: relationship with ascites and liver failure.

In patients with cirrhosis and ascites decreased renal blood flow might be related to the severity of liver disease but the relationship between the severity of cirrhosis and renal perfusion has not yet been established. Thus we measured renal, systemic and splanchnic hemodynamics in 63 patients with ascites and in 28 without ascites. When compared to patients without ascites, patients with ascites had lower renal blood flow (1,170 +/- 100 vs. 935 +/- 55 ml/min/1.73 m2; mean +/- SEM, p < 0.05) and renal perfusion pressure (78 +/- 2 vs. 72 +/- 1 mm Hg, p < 0.05 and higher inferior vena cava pressure (6.5 +/- 0.7 vs. 10.7 +/- 0.7 mm Hg, p < 0.05). Patients with ascites had significantly higher serum bilirubin concentrations, hepatic venous pressure gradient and lower serum albumin concentrations, indocyanine green (ICG) extraction than patients without ascites. Renal vascular resistance, glomerular filtration rate, mean arterial pressure, cardiac index and systemic vascular resistance were not significantly different between the two groups. By multiple regression analysis no significant correlation was found between liver tests (i.e., prothrombin time, serum bilirubin and albumin concentrations, ICG extraction), hepatic venous pressure gradient, cardiac index and systemic vascular resistance on the one hand and renal blood flow on the other. No significant correlation was found between glomerular filtration rate and liver tests. In conclusion, in patients with cirrhosis and ascites, renal hypoperfusion is not related to the severity of liver disease.

Ascites↗
PubMed1993

Persistence of systemic and splanchnic hyperkinetic circulation in liver transplant patients.

Portal pressure and portal-systemic collateral circulation after orthotopic liver transplantation have not been investigated. We studied systemic and splanchnic hemodynamics in 17 patients with cirrhosis before and 205 +/- 146 days after orthotopic liver transplantation. Among the 17 orthotopic liver transplantation patients, 12 had undergone hemodynamic study in the 6 mo before orthotopic liver transplantation. Controls were 50 patients with normal liver architecture. Cardiac index remained elevated in orthotopic liver transplantation patients compared with controls (3.6 +/- 0.9 vs 3.1 +/- 0.4 L/min.m2; p < 0.05). Azygos blood flow, which was elevated before orthotopic liver transplantation (585 +/- 402 ml/min), remained elevated after orthotopic liver transplantation (553 +/- 343 ml/min). In transplant patients, hepatic blood flow was higher than it was in controls (2.26 +/- 0.86 vs. 1.38 +/- 0.57 L/min; p < 0.05). Elevated hepatic blood flow correlated with cardiac index (r = 0.647, p < 0.025). In patients with normal graft function, hepatic venous pressure gradient was normal (2 +/- 1 mm Hg). In a patient with acute rejection, a sharp elevation in the hepatic venous pressure gradient was observed; it returned to normal 45 days after treatment. We conclude that despite normal portal pressure, portal-systemic collateral blood flow remains elevated after orthotopic liver transplantation. Possibly because of persistent collateral circulation, which may keep portal tributary blood flow elevated, hepatic blood flow is increased after orthotopic liver transplantation. Elevated splanchnic blood flow, in turn, contributes to the high cardiac index in liver recipients. Finally, a sharp elevation in portal pressure, which may be observed during acute rejection and subsides after treatment, merits further study.

Adult↗
PubMed1992

Sequence analysis of a gene cluster encoding cellulases from Clostridium cellulolyticum.

The sequence of a 5633-bp EcoRI-PvuII DNA fragment from Clostridium cellulolyticum was determined. This fragment contains two complete endo-beta-1,4-glucanase-encoding genes, designated celCCC and celCCG. These two genes are flanked by two other partial open reading frames (ORF1 and celCCE) that probably encode two cellulases or related enzymes. The celCCC and celCCG genes appear to be present in a polycistronic transcriptional unit. Northern blot hybridisations with intragenic probes derived from celCCC and celCCG gave similar patterns. Two transcripts of about 5 and 6 kb were identified. The celCCC and celCCG ORFs extend over 1380 bp and 2175 bp, respectively. They are separated by only 87 nt. A typical signal sequence is present at the N terminus of the deduced polypeptides. The mature CelCCC and CelCCG proteins have M(r)s 47,201 and 76,101, respectively. Comparisons between their amino acid (aa) sequences and other known cellulase sequences revealed that: first, they both contain the repeated 24-aa sequence characteristic of clostridial beta-glycanases, secondly, the N-terminal catalytic domains of CelCCC and CelCCG can be classified into the D and E2 families, respectively, and thirdly, the largest CelCCG contains an additional internal domain which is very similar to that of the Bacillus-type cellulose-binding domain (CBD). The ORF1-C-terminal-encoded sequence also contains the clostridial 24-aa repeat. The CelCCE N-terminus consists of a typical signal sequence followed by a 168-aa domain homologous to the N-terminal repeated domain of Cellulomonas fimi CenC. This domain is connected to an incomplete catalytic domain of family E1 by a Pro-rich junction linker.

Amino Acid Sequence↗
PubMed1992

[Identification of alcoholism and therapeutic proposals: a study in a general hospital].

Alcoholism is a frequent condition in patients admitted to general hospitals. The rate of identification of patients suspected to be alcoholic, the therapeutic measures proposed to such patients and their destination at hospital discharge were among the issues studied in the general wards of a department of internal medicine of an hospital in the French-speaking region of Switzerland. The Michigan Alcoholism Screening Test (MAST) was utilized systematically among all patients aged 20-75 years who where admitted consecutively to the department. Two cohorts matched for age and sex were thus formed: 102 alcoholics (MAST greater than or equal to 8) and 102 non-alcoholics (MAST less than or equal to 4). A diagnosis of alcoholism or of a syndrome of alcohol dependence was found in only 50% of all exit reports of the alcoholic cohort, whereas alcohol-related problems were identified on a verbal basis by the attending physician in 89% of cases. Therapeutic measures were proposed to 69% of female alcoholics and to 43% of male alcoholics, more frequently among patients with the highest MAST scores. In addition, at hospital discharge, alcoholic patients were more likely to be sent to a destination other than their place of residence than were the non-alcoholic patients. This study illustrates the low rate of identification and subsequent treatment of alcoholism among hospitalized patients. It also suggests that hospital stays should be used more frequently to increase the systematic identification of alcohol problems, increase awareness of alcoholism and provide information to both patients and those caring for them.

Adult↗
PubMed1992

Pharmacokinetics of lomefloxacin in patients with cirrhosis.

The effect of liver failure on the pharmacokinetics of lomefloxacin was studied in 12 patients with cirrhosis. Patients received a single oral dose of 400 mg lomefloxacin, and blood and urine samples were collected at intervals over the next 48 hours. The concentrations of lomefloxacin in all samples were measured using high-pressure liquid chromatography (HPLC). The mean (+/- standard deviation) maximum plasma concentration (Cmax) in these patients was 3.9 +/- 1.20 micrograms/mL. The mean time to maximum serum concentration (Tmax) was 2.1 +/- 2.6 hours, and the mean elimination half-life (t1/2) was 9.16 +/- 1.93 hours. Mean renal clearance was 88.9 +/- 38.0 mL/min/1.73 m2, and the mean nonrenal clearance was 61.6 +/- 19.0 mL/min/1.73 m2, which corresponded to 41% of the total body clearance. No correlations were observed between nonrenal clearance and hepatic insufficiency (Pugh score) or nonrenal clearance and plasma bilirubin. These results show that liver failure does not per se affect lomefloxacin kinetics. Thus, no adjustments in lomefloxacin dosages appear to be necessary for patients with impaired liver function tests.

Adult↗
PubMed1992

Plasma catecholamine concentrations are a reliable index of sympathetic vascular tone in patients with cirrhosis.

In patients with cirrhosis, the significance of elevated plasma catecholamine concentrations is unclear. Thus we investigated the relationship between plasma catecholamine concentrations and the hemodynamic effect of pindolol (an index of sympathetic vascular tone) in 10 patients with cirrhosis. Systemic and splanchnic hemodynamics and plasma catecholamine concentrations in the pulmonary artery and the splanchnic veins (hepatic and azygos veins) were studied before and after the oral administration of pindolol (20 mg). In basal conditions patients exhibited a hyperkinetic circulatory syndrome and elevated plasma catecholamine concentrations. Alterations in basal hemodynamics were correlated with plasma epinephrine concentrations but not with norepinephrine. Pindolol administration significantly decreased heart rate and increased right atrial pressure. After pindolol administration, individual hemodynamic changes (cardiac index, systemic vascular resistance, wedged hepatic venous pressure) were significantly correlated with plasma catecholamine concentrations. In conclusion, this study shows that in cirrhotic patients epinephrine may play a role in hemodynamic alterations, and plasma catecholamine concentrations are an index of sympathetic vascular tone.

Epinephrine↗
PubMed1992

Hemodynamic effects of terbutaline, a beta 2-adrenoceptor agonist, in conscious rats with secondary biliary cirrhosis.

The hemodynamic responses to terbutaline - a selective beta 2-adrenoceptor agonist - were studied in conscious normal rats and in conscious rats with secondary biliary cirrhosis. Compared with those of normal rats, dose-response curves in cirrhotic rats indicated significantly decreased reactivity in arterial pressure and heart rate. Half-maximal effective dose was not significantly different between the two groups. Terbutaline induced significant, dose-dependent decreases in portal pressure in both normal rats (9.3%) and cirrhotic rats (13.8%). In normal rats, terbutaline administration (32 micrograms.min-1.kg-1 body wt) increased both cardiac output and portal tributary blood flow, thus mimicking hemodynamic changes in cirrhotic rats. In cirrhotic rats, despite a significant increase in portal tributary blood flow (from 19.9 +/- 1.7 ml/min to 22.7 +/- 1.5 ml/min), terbutaline decreased portal pressure from 17.4 +/- 1.0 mm Hg to 15.0 +/- 0.8 mm Hg. This study indicates that increased beta 2-adrenoceptor stimulation in cirrhotic rats may be involved in hyperdynamic circulation. The association of a decreased portal pressure and increased splanchnic blood flow suggests that beta 2-adrenoceptor stimulation may modulate hepatic and portal collateral vascular resistance.

Adrenergic beta-Agonists↗
PubMed1992

Total effective vascular compliance in patients with cirrhosis: a study of the response to acute blood volume expansion.

Although arterial vasodilation is a well-known feature in patients with cirrhosis, the venous system remains unexplored. To measure total effective vascular compliance, a reflection of the properties of the venous system, rapid volume expansion (300 ml of a gelatin solution in 3 min) was performed in 23 patients. Eleven patients had compensated cirrhosis (Child-Pugh grade A or B), and eight had decompensated cirrhosis (Child-Pugh grade C). Four control patients had mild chronic hepatitis, normal hepatic venous pressure and normal liver architecture. Cardiac index, hepatic venous pressures, hepatic and azygos blood flow and renal plasma flow were measured before and immediately after volume expansion. Right atrial pressure was recorded during volume expansion. This allowed the calculation of total effective vascular compliance, which was higher in patients with decompensated cirrhosis than in those with compensated cirrhosis (4.65 +/- 4.21 vs. 1.34 +/- 0.63 ml.mm Hg-1.kg-1; p less than 0.05). In response to volume expansion, renal vascular resistance decreased significantly in patients with compensated cirrhosis, but not in those with decompensated cirrhosis (-30% +/- 33% vs. +2% +/- 23%; p less than 0.05). No change was seen in glomerular filtration rate. Systemic oxygen consumption increased in patients with compensated cirrhosis, but not in those patients with decompensated cirrhosis (25% +/- 33% vs. -4% +/- 9%; p less than 0.05). Although in all patients with cirrhosis volume expansion increased central venous pressures, azygos blood flow and the hepatic venous pressure gradient did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Persistence of a hyperdynamic circulation in cirrhotic rats following removal of the sympathetic nervous system.

The sympathetic nervous system is thought to play a role in the pathogenesis of the hyperdynamic circulation associated with portal hypertension. However, the extent of this role is unknown. After elimination of all neurological control by pithing, systemic and regional hemodynamics were studied in rats with portal hypertension caused by either portal vein stenosis or biliary cirrhosis. In normal rats, pithing induced a two-thirds decrease in mean arterial pressure and cardiac index. Compared with pithed normal rats, pithed portal vein-stenosed rats showed similar values for mean arterial pressure, cardiac index, and portal tributary blood flow. In contrast, pithed cirrhotic rats still showed hyperdynamic circulation with increased cardiac index and portal tributary blood flow. Although pithing dramatically reduced portal pressure in all groups, portal pressure remained significantly higher in portal hypertensive rats than in normal rats. These results indicate that in rats with portal vein stenosis, the sympathetic nervous system plays a major role in hemodynamic alterations, whereas in rats with cirrhosis, nonneurogenic factors participate in the pathogenesis of the hyperdynamic circulation.

Animals↗
PubMed1992

Hemodynamic, neurohumoral, and metabolic responses to amino acid infusion in patients with cirrhosis.

In patients with cirrhosis the renal response to amino acid infusion is controversial. In addition, the renal and systemic metabolic effects of amino acids are unknown. Therefore, the present study examined the effects of amino acids on renal hemodynamics, renal and systemic oxygen (O2) consumption, and hormones in patients with cirrhosis. Twelve patients received an 8% amino acid solution for 30 minutes at a rate providing 250 mg of amino acids/kg body wt. Renal blood flow increased by 45% (P less than 0.05) and the glomerular filtration rate by only 9% (P greater than 0.05). Renal vascular resistance decreased by 23% (P less than 0.05), and renal perfusion pressure did not change significantly. Renal and systemic O2 consumption and pulmonary artery plasma glucagon level significantly increased. There were no significant changes in plasma osmolality, plasma volume, and plasma atrial natriuretic peptide concentrations. In conclusion, the results show that amino acid-induced renal vasodilation caused hyperperfusion but not renal hyperfiltration in patients with cirrhosis. In addition, renal hyperemia was associated with renal and systemic hypermetabolism.

Amino Acids↗