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Biomedical subjects

A Bernard

Publications and source records attributed to A Bernard.

At least 361 records · Page 20Linked to original sources
PubMed1991

Absorption and intestinal catabolism of fatty acids in the rat: effect of chain length and unsaturation.

Simultaneous portal blood absorption and intestinal mucosal catabolism of labelled fatty acids were investigated. Anaesthetized adult Wistar rats were infused intraduodenally either with 90 mumol of capric (C10:0), oleic (C18:1), linoleic (C18:2) or arachidonic (C20:4) 1-14C acids or with 30 mumol of each labelled fatty acid in addition to 30 mumol of oleic acid and 30 mumol of monopalmitin. For mixed infusates, experiments were carried out with two additional long-chain fatty acids: palmitic (C16:0) and erucic (C22:1) 1-14C acids. Radioactivity was quantified in the lipids and in the catabolic products in portal blood recovered at 5 min intervals for 1 h after infusion. At the end of the experiment, the disappearance of radioactivity from the mucosa was quantified. When labelled fatty acids were infused alone, 49% of the radiolabelled lipid disappearing from the mucosa was recovered in the blood for C10:0, but only 7.8% for C18:1, 6.4% for C18:2 and 10.6% for C20:4. With mixed infusates, 41% of the radiolabelled lipid disappearing from the mucosa was recovered in the blood for C10:0 compared with 12% for C18:1, 10.2% for C18:2, 10.5% for C20:4 and 2.7% for C16:0 and 2% for C22:1. Labelled catabolites appear with the same profiles as those of the respective fatty acids in blood. These studies confirm a minor absorption into blood of long-chain fatty acids compared to the medium-chain fatty acids and highlight differences in the catabolism of the fatty acids according to their chain length and their degree of unsaturation. The differences might be related to the differences in the fatty acid hydrosolubility and to their different affinities for the I- and L-cytosolic fatty acid binding proteins. These phenomena may be important in nutrition in relation to the availability of essential fatty acids.

Absorption↗
PubMed1991

Effects of exposure to cadmium on calcium metabolism: a population study.

The objective was to investigate the hypothesis that environmental exposure to cadmium may affect calcium metabolism in the population at large. The 1987 participants (965 men and 1022 women), from 20 to 80 years old, constituted a random sample of the population of four Belgian districts. The urinary excretion of cadmium, a measure of lifetime exposure, averaged 9.3 nmol/24 h in men (range 0.4-324 nmol/24 h) and 7.1 nmol/24 h (range 0.1-71 nmol/24 h) in women. Serum alkaline phosphatase activity and the urinary excretion of calcium correlated significantly and positively with urinary cadmium excretion in both men and women, and serum total calcium concentration negatively with urinary cadmium excretion in men only. The regression coefficients obtained after adjustment for significant covariates indicated that when urinary cadmium excretion increased twofold, serum alkaline phosphatase activity and urinary calcium excretion rose by 3-4% and 0.25 mmol/24 h respectively, whereas in men serum total calcium concentration fell by 6 mumol/l. After adjustment for significant covariates the relation between serum total calcium concentration and urinary cadmium excretion was not significant in women. The findings suggest that even at environmental exposure levels calcium metabolism is gradually affected, as cadmium accumulates in the body. The morbidity associated with this phenomenon in industrialised countries remains presently unknown and requires further investigation.

Adult↗
PubMed1991

Linoleic acid chyloportal partition and metabolism during its intestinal absorption.

1-14C linoleic acid intestinal absorption and simultaneous biochemical events were followed up on rats under vascular perfusion and on main mesenteric lymphatic duct fistulated rats. 1-14C linoleic acid was introduced in the duodenum alone in doses from 1.2 to 90 mumol or in the presence of oleic acid and monopalmitin (30/30/30 mumol/mumol/mumol). Mesenteric portal venous blood and chyle, respectively, were collected continuously for 1 and 6 h after the infusions. Blood-labeled lipid recovery varied from 4.7 to 2.2% of the 14C linoleic acid infused as the 14C linoleic acid dose infused increased, and dropped to 1.8% with the mixed lipid infusate. Lymph-labeled lipid recovery increased from 25.7 to 31.8% of the 14C linoleic acid infused as the dose infused increased, and rose to 48.1% with the mixed lipid infusate. The oxidation of 1-14C linoleic acid remained low: 0.8-3% of the infused radioactivity. A desaturation and elongation of 14C linoleic acid into 14C arachidonic acid was detected and discussed. We can conclude that the linoleic lymph absorption pathway remained preferential in our experimental conditions, simultaneous to a low rate of oxidation and an eventual ability for the enterocyte to convert this essential fatty acid arachidonic acid.

Animals↗
PubMed1991

Proteinuria: changes and mechanisms in toxic nephropathies.

During the last few decades, considerable progress has been made in the understanding of the pathophysiological mechanisms of proteinuria. A great variety of hemodynamic or biochemical mechanisms acting at different sites of the nephron have been shown to alter the renal handling and the urinary excretion of proteins. The finding which perhaps has had most practical implications is that the pattern of protein excretion quantitatively and qualitatively varies with the site and severity of renal damage. This has led to the development of a large array of methods for the identification and quantitation of specific urinary proteins. These methods have been most extensively used by toxicologists in experimental, epidemiological, or clinical studies on potentially nephrotoxic chemicals (e.g., drugs, heavy metals, solvents, etc.). The present review summarizes the current state of knowledge on the mechanisms of proteinuria and the use of urinary proteins as indicators of nephrotoxicity.

Animals↗
PubMed1991

[Dumbbell-shaped nerve-tissue tumors of the posterior mediastinum. Apropos of 5 cases].

The authors present 5 cases of dumbbell neurogenic tumors with intraspinal extension. There were 4 neurilemmomas in four adults and 1 ganglioneuroma in one child. These tumors were benign. Neurological signs were observed in two cases. Widening of the intervertebral foramen at the level of the tumor is a very suggestive sign of dumbbell tumor confirmed by CT-Scan or MRI. Precise morphologic features must be assessed before embarking on the operation. The procedures used were: thoracotomy only in two cases, laminectomy then thoracotomy because of neurological signs in two cases, thoracotomy then laminectomy to fully remove tumor remnants in one case. No major morbidity was noted. The neurological symptoms resolved in two cases. A combined two-team approach with thoracic and neurosurgeons working together has not been used so far, but this possibility is probably the best choice for the future.

Adult↗
PubMed1991

[Dumbbell neurogenic tumors of the posterior mediastinum. Apropos of five cases].

The authors present 5 cases of dumbbell neurogenic tumors with intraspinal extension. There were 4 neurilemmomas in four adults and 1 ganglioneuroma in one child. These tumors were benign. Neurological signs were observed in two cases. Widening of the intervertebral foramen at the level of the tumor is a very suggestive sign of dumbbell tumor confirmed by CT-Scan or MRI. Precise morphologic features must be assessed before embarking on the operation. The procedures used were: thoracotomy only in two cases, laminectomy then thoracotomy because of neurological signs in two cases, thoracotomy then laminectomy to fully remove tumor remnants in one case. No major morbidity was noted. The neurological symptoms resolved in two cases. A combined two-team approach with thoracic and neurosurgeons working together has not been used so far, but this possibility is probably the best choice for the future.

Adult↗
PubMed1991

[Practical role of ultrasonography and clinical examination for the diagnosis of acute appendicitis. Prospective study].

The aim of this 100-patient prospective study was to compare three types of investigations in the diagnosis of acute appendicitis: initial clinical examination, initial appendicular ultrasound examination, and final results of repeated clinical examinations carried out within the first 48 hours. Final results included initial evaluation, obvious clinical results and definitive results from patients under 48 hour observation for uncertain diagnosis. Clinical initial or appendicular ultrasound examinations were poorly contributive to diagnosis (overall accuracy: 76 percent). On the contrary, repeated clinical examinations yielded a 100 percent sensitivity, a 94 percent specificity, a 94 percent positive predictive value, a 97 percent negative predictive value and a 97 p. 100 overall accuracy. No morbidity was noted in observing patients for 48 hours. Unwarranted appendectomies were carried out in 3 percent of cases. Ultrasonography of the appendix seems useful for the differential diagnosis of acute appendicitis.

Acute Disease↗
PubMed1991

[Demonstration of viral proteins and RNA in hypothalamus of mice infected by canine distemper virus].

There are a number of reports suggesting that neurological disorders may be due to infectious agents, such as viruses. In order to study the role of viruses on cellular plasticity in the central nervous system, we established a model of virus infection in the mouse. Inoculation of mouse with canine distemper virus (CDV) led to an acute encephalitis, late neurological disorders and an obesity syndrome. To analyse the role of viral replication on the development of this syndrome we studied the cerebral distribution of viral products during the course of infection. Viral proteins and RNA accumulated in mouse brain from the 9th day to the 6th week post-inoculation, particularly in hypothalamus, a cerebral structure implicated in obesity. Such selective viral tropism may explain some of the unexpected features of viral-induced disorders.

Animals↗
PubMed1991

Is intraperitoneal tobramycin ototoxic in CAPD patients?

In 40 CAPD patients treated for peritonitis, the authors did a prospective study of ototoxic effects of intraperitoneal tobramycin. They evaluated cochlear function in pure-tone threshold audiograms over a range of frequencies from 250-10,000 Hz, in the speech-reception threshold test and in the speech-discrimination test. These tests were performed within 48 hours of initiation of tobramycin treatment and within 2 or 3 weeks of the drug's discontinuation. With the aminoglycoside doses used in this study, no statistical difference between the mean baseline and mean follow-up hearing levels was seen in these 40 patients. However, according to the standard criteria of ototoxicity, the hearing in 10 of 40 patients (25%) deteriorated after tobramycin, while it improved in seven patients (17.5%). In the remaining 23 (57.5%), hearing remained stable. With respect to the risk factors for ototoxicity such as advanced age, increased duration of treatment, elevated plasma aminoglycoside levels, concomitant treatment with other ototoxic drugs, pre-existing hearing loss, renal dysfunction and hyperthermia, no statistically significant difference was demonstrated between the patients with deteriorated, stable or improved hearing. The results of this study do not confirm that tobramycin given intraperitoneally to CAPD patients produces auditory toxicity. The hearing deterioration observed in 10 patients may be due to synergistic factors. The improvement observed in 7 patients could not be explained.

Audiometry, Pure-Tone↗
PubMed1991

[Quantification of mRNA coding for enterocyte fatty acid binding proteins (FABP) in rats: effect of high lipid diet and starvation].

We have tested in adult rat the specificity and the sensitivity of two cDNA probes derived from recombinant plasmids pJG19 and pJG418. The Northern blot analysis of total RNA extracted from small bowel reveals 0.9 and 0.7 kb mRNA corresponding respectively to the I and L-FABPc mRNA. A linear relation occurs between the amounts of input total RNA and the quantities of specific mRNA found by hybridization with cDNA probes (r = 0.991 and r = 0.998 for I and L-FABPc respectively). We have also evaluated the effect of drastic nutritional status: a high fat diet containing 45% of lipids and a starvation of three days. A two fold increase in I and L-FABPc mRNA occurs in starved rats. By contrast, only the I-FABPc mRNA are slightly enhanced after the hyperlipidic diet (50%). These preliminary results, which must be confirmed by further experiments, suggest a differential nutritional regulation of I and L-FABPc gene expression in rat intestine.

Animals↗
PubMed1991

[Prevention of postoperative wound dehiscence. Comparative study of polyglactin 910 mesh and total reinforced extraperitoneal sutures].

Postoperative wound dehiscence is a serious complication. Various surgical procedures have been proposed to prevent it but only few studies have compared their effectiveness. The authors report a retrospective study on 292 high risk patients operated between 1980 and 1988. These patients were divided in two groups according to the methods of abdominal wall support: 226 patients (group I) with total reinforced extraperitoneal sutures and 66 (group II) with a polyglactin 910 mesh. Preoperative risk factors, surgical pathology and the incisions performed were similar in the two groups. Only two parameters were different: the number of previous operations and emergency surgery which were more frequent in group II (p less than 0.05). Fourteen patients in group I developed postoperative wound dehiscence and none in group II (p = 0.02). Nine of these patients were reoperated with a mortality of 28.5%. The frequency of the other complications was similar in the two groups. Polyglactin 910 mesh was more effective than total reinforced extraperitoneal sutures in the prevention of post operative wound dehiscence justifying its use in high risk patients.

Aged↗
PubMed1991

[Cavernous hemangioma of the liver associated with angiosarcoma: malignant transformation?].

Angiosarcoma of the liver is a rare tumor. Its treatment is usually regarded as unsuccessful and its prognosis extremely poor. The authors report the case of a solitary and encapsulated hepatic tumor characterized by the association of a cavernous hemangioma surrounded by an angiosarcoma. The hypothesis of an eventual malignant transformation of cavernous hemangiomas of the liver is raised.

Adult↗
PubMed1990

Urinary proteins and red blood cell membrane negative charges in diabetes mellitus.

The nature and origin of proteinuria in diabetes mellitus have been investigated by measuring the urinary excretion of seven specific proteins of low (beta 2-microglobin, retinol-binding protein) or high molecular weight (albumin, transferrin, hemopexin and IgG). Using the Alcian Blue binding test, we also measured negative charges on red blood cell (RBC) membrane which according to recent studies might mirror the glomerular polyanion charge. A group of 190 diabetics was examined, including 90 patients with type I diabetes, 23 type II diabetics treated with diet and/or hypoglycaemic agents and 77 longstanding type II diabetics requiring insulin therapy. With the exception of beta 2-microglobulin all proteins measured were excreted in the urine of diabetics in significantly higher amounts than in controls. The assay of transferrin proved the most sensitive (58% positive) followed by albumin (49%), IgG (34%), hemopexin (28%) and retinol-binding protein (26%). Practically the same ranking was obtained when only type I diabetics were considered. RBC membrane negative charges were diminished in diabetics and negatively correlated with the urinary excretion of albumin (r = -0.61, n = 190). RBC charges were also negatively correlated with other urinary proteins of high molecular mass (r between - 0.5 and - 0.2) but presented no relation with urinary beta 2-microglobulin or retinol-binding protein. The loss of RBC charges in diabetics most likely reflects the concomitant depletion of the glomerular polyanion responsible for the increased glomerular leakage of high molecular mass plasma proteins. The preferential increase in transferrin excretion together with the progressive rise in the urinary excretion of IgG lead us to postulate that the loss of glomerular polyanion in diabetes is accompanied, from the early stage, by a progressive decrease in the size-selectivity of the glomerular filter. The urinary excretion of retinol-binding protein was weakly correlated with albuminuria (r = 0.26, n = 186). Eight % of diabetics showed an elevation of urinary retinol-binding protein without evidence of microalbuminuria, which clearly demonstrates that a proximal tubular impairment can occur independently of the glomerular alterations in the course of diabetic nephropathy.

Adult↗
PubMed1990

Renal effects of cadmium body burden of the general population.

In a cross-sectional population study to assess whether environmental exposure to cadmium is associated with renal dysfunction, 1699 subjects aged 20-80 years were studied as a random sample of four areas of Belgium with varying degrees of cadmium pollution. After standardisation for several possible confounding factors, five variables (urinary excretion of retinol-binding protein, N-acetyl-beta-glucosaminidase, beta 2-microglobulin, aminoacids, and calcium) were significantly associated with the urinary excretion of cadmium (as a marker of cadmium body burden), suggesting the presence of tubular dysfunction. There was a 10% probability of values of these variables being abnormal when cadmium excretion exceeded 2-4 micrograms/24 h. Excretion reached this threshold in 10% of non-smokers. There was also evidence that diabetic patients may be more susceptible to the toxic effect of cadmium on the renal proximal tubule.

Acetylglucosaminidase↗
PubMed1990

Preparation and characterization of human interleukin-5 expressed in recombinant Escherichia coli.

The gene coding for human interleukin-5 was synthesized and expressed in Escherichia coli under control of a heat-inducible promoter. High-level expression, 10-15% of total cellular protein, was achieved in E. coli. The protein was produced in an insoluble state. A simple extraction, renaturation and purification scheme is described. The recombinant protein was found to be a homodimer, similar to the natural murine-derived protein. Despite the lack of glycosylation, high specific activities were obtained in three 'in vitro' biological assays. Physical characterization of the protein showed it to be mostly alpha-helical, supporting the hypothesis that a conformational similarity exists among certain cytokines.

Amino Acids↗
PubMed1990

[Glomerular erythrocytes, albuminuria, glycosaminoglycans and exposure to hydrocarbons].

As part of a study on the possible nephrotoxicity of hydrocarbons, the urinary erythrocyte concentration and the percentage of glomerular erythrocytes were assessed. Albumin excretion rate, glycosaminoglycan and retinol-binding protein concentration, and N-acetyl-beta-glucosaminidase activity were measured simultaneously. The results show that the erythrocyte concentration and the percentage of glomerular erythrocytes tend to increase with hydrocarbon exposure, and that a nephrotoxic effect of occupational hydrocarbon exposure deserves consideration.

Acetylglucosaminidase↗
PubMed1990

Helper or cytolytic functions can be selectively induced in bifunctional T cell clones.

By using bifunctional T cell populations, we have shown in this report that elicitation of helper versus cytolytic function depends on the stimulatory signal at the membrane. Interestingly enough, the transduction of these signals is likely to be achieved via different metabolic pathways. Thus, helper function is associated with intracellular Ca2+ mobilization and PLC activation, while cytolysis can occur even in the absence of detectable levels of these second messengers. These results indicate that selective activation through the same membrane-transducing molecule may orientate T cell function through qualitatively or quantitatively different second messengers. This would be an important part of immune regulation.

Antibodies, Monoclonal↗