Effects of amino acids on bile acid-dependent and independent bile flow in the isolated perfused rat liver.

Background/aims: Conflicting data on the effects of amino acids on biliary function led us to investigate their interaction with taurocholate in the perfused rat liver model.

Methods: To investigate the influence of amino acids on the bile acid-independent component of bile flow, 12 livers were perfused with (n = 6) and without (n = 6) amino acid addition from t30 min. For the study of bile acid-dependent bile flow, 24 livers were perfused under 8 experimental conditions according to the perfusate taurocholate concentration (12.

Intestinal absorption and permeability in human immunodeficiency virus-infected patients.

Background: Impaired intestinal function could account for diarrhoea and weight loss, which are common features of advanced human immunodeficiency virus (HIV) infection.

Methods: We assessed intestinal permeability to lactulose and mannitol and absorption of D-xylose in 96 HIV-infected patients (group I: asymptomatic subjects (CDC-A); group II: symptomatic subjects (CDC-B or C) without body weight loss and/or diarrhoea; group III: 25 acquired immunodeficiency syndrome (AIDS) patients (CDC-C) with severe body weight loss and/or diarrhoea) and 10 healthy subjects as controls.

Results: An incremental decrease in urinary D-xylose recoveries was observed, with all groups statistically different from each other.

Is the L-arginine-nitric oxide pathway involved in endotoxemia-induced muscular hypercatabolism in rats?

We investigated the role of the nitric oxide (NO) synthase (NOS) pathway in muscular metabolism during endotoxemia in four groups of male Wistar rats. Two groups were injected with the lipopolysaccharide (LPS) of Escherichia coli (3 mg/kg), with one group treated using N(G)-nitro-L-arginine methylester ([L-NAME] 85 mg/kg/d) and the other not. The two control groups included one treated with L-NAME and the other not.

Direct cytotoxicity of hypoxia-reoxygenation towards sinusoidal endothelial cells in the rat.

Aims/background: Sinusoidal endothelial cells are the primary target of ischemia-reperfusion injury following liver preservation. The present study was undertaken to examine the susceptibility of sinusoidal endothelial cells to hypoxia-reoxygenation and the potential role of oxygen free radicals in the induction of cell injury.

Methods: Sinusoidal endothelial cells were isolated from rat liver.

Plasma concentration, kinetic constants, and gene polymorphism of angiotensin I-converting enzyme in centenarians.

We have determined serum activity and kinetic constants of angiotensin I-converting enzyme (ACE), parallel to an insertion/deletion (I/D) polymorphism in its gene, in French centenarians and controls 20-70 years of age because this enzyme could have an impact on cardiovascular risk, and thus on longevity. Both the ACE D allele and ACE D/D genotype were more frequent in centenarians in comparison with controls, without sex-related differences nor significant correlation with a cardiovascular pathology. In centenarians, I/D polymorphism was correlated with circulating ACE activity (D/D genotype, 89.

TNF-alpha and IL-6 synergistically inhibit ketogenesis from fatty acids and alpha-ketoisocaproate in isolated rat hepatocytes.

Background: During sepsis, lipid metabolism is shunted toward triacylglycerol synthesis and hepatic lipogenesis. A decrease in ketogenesis from free fatty acids also is observed, probably mediated by cytokines involved in host response to infection. Whether such an inhibition of ketogenesis occurs with other ketone body precursors such as ketoacids is not known.

Qualitative and quantitative analysis of hemoglobin variants by capillary isoelectric focusing.

We developed two capillary isoelectric focusing (CIEF) assays, in narrow pH gradients, with the aim of routinely separating and quantitating normal and abnormal hemoglobins (Hbs): a one-step CIEF assay where residual electroosmotic flow mobilizes the proteins during focalization, and a two-step CIEF assay where focused Hbs are mobilized by low pressure by maintaining high-voltage. The resolution of 0.10 pH unit obtained with the one-step assay allowed the separation of the Hbs A, F, S and C; but Hb A2, which represents about 2-3% of whole Hb, could not be quantitated.

A randomized controlled trial of the influence of the mode of enteral ornithine alpha-ketoglutarate administration in burn patients.

To investigate appropriate mode and daily dose of enteral ornithine alpha-ketoglutarate (OKG) administration, 54 burn patients (total burn surface area: 20-50%) were included in a randomized controlled trial and assigned to receive either a supplement of OKG (10, 20 or 30 g/d) as bolus or continuous infusion, or a continuous infusion of an isonitrogenous amount of a soy protein mixture (Protil-1: 10, 20 or 30 g/d) in addition to their enteral diet. The influence of these treatments on clinical outcome and biological indices was evaluated. OKG administration significantly improved nitrogen balance and reduced 3-methylhistidine and hydroxyproline urinary elimination.

Standardization of the lactulose-mannitol test in rats: application to burn injury.

Intestinal permeability can be assessed by measuring urinary mannitol and lactulose excretion after oral administration. This test may be useful as a tool in experimental studies to explore the effects of specific diets intended to promote the repair of the integrity of the gut barrier. In this study we standardized the lactulose-mannitol test in rats and applied it to a burned-rat model.

Pharmacokinetic assessment of an oligopeptide-based enteral formula in abdominal surgery patients.

The specific effect of the molecular form of the nitrogen supply (oligopeptides and whole proteins) on amino acid kinetics during enteral feeding after surgery has not been assessed previously. In a prospective, randomized study, patients having undergone esophagectomy or gastrectomy for cancer received jejunal infusions of oligopeptide-based or whole-protein-based complete formulas (OPD and WPD, respectively) during two 9-h periods on 2 consecutive days in a crossover design. The OPD and WPD had identical energy compositions and amino acid profiles.

Capillary isoelectric focusing and high-performance cation-exchange chromatography compared for qualitative and quantitative analysis of hemoglobin variants.

We have developed two assays for complete analysis of hemoglobins (Hbs) in the field of hemoglobinopathies: a high-performance cation-exchange liquid chromatography (HPLC) assay on the weak cation-exchanger Poly Cat A and a two-step capillary isoelectric focusing (CIEF) assay on the neutral-coated capillary from Beckman in a narrow pH gradient. The resolution was satisfactory for both HPLC and CIEF and allowed separation of normal and common abnormal Hbs, i.e.

Amino acid determination in biological fluids by automated ion-exchange chromatography: performance of Hitachi L-8500A.

The Hitachi L-8500A is a newly available apparatus for amino acid (AA) analysis that allows automatic on-line mixing of the ninhydrin reagent. The within-run precision (human plasma pools at three different concentrations) showed CVs < 3.8% except for the lowest concentration of citrulline (4.

[Fibronectin and hyaluronic acid in seminal fluid: relationship with sperm count and percentage of typical forms].

Two components of the extra cellular matrix, hyaluronic acid (HA) and fibronectin (Fbn), were assessed in the seminal fluids of 29 patients submitted for diagnosis of infertility. The concentrations of HA and Fbn were elevated in seminal plasma in comparison to their ranges of concentration in normal sera. No correlations were found between seminal Fbn and sperm count per ml and/or ejaculate, normal sperm cytology and multiple anomaly index (MAI).

Structural and biological roles of glycosylations in pulmonary angiotensin I-converting enzyme.

We enzymatically deglycosylated pig lung angiotensin I-converting enzyme (ACE) to study the involvement of its glycanic chains in its physicochemical and catalytic properties. The effects of endoglycosidases F2 and H, and of N-glycanase were assessed by ACE mobility in SDS-PAGE. N-Glycanase only was completely effective with or without previous denaturation, leading to a shift in ACE M(r) from 172 to 135 kDa; endoglycosidase F2 produced the same shift but only without previous denaturation.

Deletion of hydroxyethylstarch from University of Wisconsin solution induces cell shrinkage and proteolysis during and after cold storage of rat liver.

Among the numerous components of the University of Wisconsin (UW) solution used for organ preservation, the usefulness of hydroxyethylstarch (HES), the colloido-osmotic support of this solution, is controversial. The aim of our study was to determine the influence of HES on hepatic metabolism and intracellular hydration state during hypothermic preservation and after reperfusion in a model of isolated perfused rat liver. Three groups of eight livers were perfused either immediately or after 18 hours of cold storage in a UW-based preservation solution with or without HES.

Ornithine alpha-ketoglutarate metabolism after enteral administration in burn patients: bolus compared with continuous infusion.

Ornithine alpha-ketoglutarate (OKG) has been successfully used as an enteral supplement in the treatment of catabolic states, including burn injury. However, specific questions remain unanswered concerning burn patients, including OKG metabolism and metabolite production, appropriate mode of administration, and dose. We thus performed a kinetic study and followed plasma ornithine and OKG metabolite concentrations on day 7 postburn in 42 (35 men, 7 women) consecutive burn patients aged 33 +/- 2 y with a mean (+/-SEM) total burn surface area (TBSA) of 31 +/- 1%.

Cytotoxicity of amiodarone in cultured human endothelial cells.

As damage to the pulmonary vascular endothelium may be responsible for the lung toxicity of amiodarone, we evaluated the cytolytic toxicity of the drug in cultures of endothelial cells. Cells were cultured from human umbilical cord veins. Amiodarone caused a vacuolization of the cells with liberation of both lactate dehydrogenase (LDH) and angiotensin-converting enzyme (ACE) in the culture medium.

Serum levels of endothelial injury markers creatine kinase-BB and soluble thrombomodulin during human liver transplantation.

Endothelial damage within the sinusoids of the liver probably plays a key role in primary liver dysfunction following transplantation. The aim of this work was to study the serum levels of two potential markers of endothelial damage, creatine kinase-BB and soluble thrombomodulin, during human graft revascularization. Thirteen human liver grafts were preserved in UW solution (mean time: 13.

Kinetic nephelometric determination of albumin produced by rat hepatocytes in culture.

A kinetic immunonephelometric method for the determination of albumin produced by rat hepatocytes in culture is described. This assay is simple, rapid and sensitive. The methodology allows detection of 0.

Diagnostic accuracy of hyaluronan and type III procollagen amino-terminal peptide serum assays as markers of liver fibrosis in chronic viral hepatitis C evaluated by ROC curve analysis.

Diagnostic accuracy of two serum markers of liver fibrosis, hyaluronan (HA) and amino-terminal peptide of type III procollagen (P-III-P), was studied in a cohort of 326 untreated patients with chronic viral hepatitis C. Both P-III-P (RIA-gnost P-III-P, Behring Diagnostic) and HA (HA-test, Pharmacia) serum concentrations correlated with the histological grades of liver fibrosis (P < 0.001).

Plasma alpha-glutathione S-transferase assessed as a marker of liver damage in patients with chronic hepatitis C.

alpha-Glutathione S-transferase (alpha-GST; EC 2.5.1.

Changes in systemic gonadal and adrenal steroids in asymptomatic human immunodeficiency virus-infected men: relationship with the CD4 cell counts.

Serum sex hormone-binding globulin (SHBG), testosterone, non-SHBG-bound testosterone, androstenedione, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and cortisol were measured in 58 homosexual men seropositive for human immunodeficiency virus (HIV), all clinically asymptomatic (Centers for Disease Control 1993 classification stage A). The HIV patients were divided into four groups according to the CD4 lymphocyte count--group 1 (more than 500/microliters, N = 14), group 2 (between 350 and 500/microliters, N = 16), group 3 (between 200 and 349/microliters, N = 22) and group 4 (less than 200/microliters, N = 6)--and compared with 11 antibody-negative men as controls. The SHBG levels were significantly increased in groups 1, 2, 3 (p < 0.

Evidence for the detrimental role of proteolysis during liver preservation in humans.

Background/aims: Proteolysis may persist in the liver allograft during cold storage. The aim of this study was to determine the significance of proteolysis within liver allografts stored at 4 degrees C in University of Wisconsin preservation fluid.

Methods: Thirty recipients of 32 liver allografts were studied prospectively.

No evidence for a tumor necrosis factor alpha stimulated 2-methylaminoisobutyric acid uptake in hepatocyte monolayer.

This study investigates the short-term effects of glucagon and human recombinant tumor necrosis factor alpha (TNF alpha) singly and in association on 2-methylaminoisobutyric acid (MeAIB) transport in hepatocyte monolayers. As expected, glucagon induced a time-dependent stimulation of MeAIB transport. In our experimental conditions, TNF alpha did not induce cytolysis.