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Biomedical subjects

M Krempf

Publications and source records attributed to M Krempf.

At least 91 records · Page 5Linked to original sources
PubMed1995

Measurement of mevalonic acid in human urine by bench top gas chromatography-mass spectrometry.

Urinary excretion of mevalonate was reported to be correlated with endogenous cholesterol biosynthesis. A method is described whereby mevalonate (MVA) concentration in urine is determined by bench top gas chromatography-mass spectrometry after extraction as mevalonalactone (MVL) and conversion to mevalonolactone mono-TMS derivative. Within- and between-assay coefficients of variation were 4.02% and 8%, respectively. The mean concentration of MVA in 24-h urine collections from ten normolipidemic urinary subjects was 203 +/- 49.6 ng/ml (range: 44-576 ng/ml). Administration of 40 mg of Pravastatin (an HMG-CoA reductase inhibitor) significantly decreased (approximately 50%) the night concentration of MVA in five healthy volunteers. This assay could be useful for investigation of endogenous cholesterol synthesis rate in various dyslipidemias and in response to drug treatment.

Adult↗
PubMed1995

[Disseminated aspergillosis with pulmonary and cardiac localization in an HIV-infected patient].

The authors report a case of invasive aspergillosis with pulmonary and cardiac involvement revealed by a pericarditis in a seropositive patient (VIH1). Clinical findings, differential diagnosis and outcome underly the issues encountered in the management of aspergillosis in AIDS patients. Indeed, the low prevalence of aspergillosis in AIDS and the insidious features of aspergillosis locations make the early diagnosis difficult. It is though essential for a favourable outcome under specific treatment. The risk factors, clinical characteristics and diagnostic procedures are mentioned as well as the various available treatments.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Effect of acetate and propionate on fasting hepatic glucose production in humans.

OBJECTIVE: Short chain fatty acids (SCFA, e.g. acetate and propionate) produced from bacterial colonic fermentation may be involved in the improvement of fasting glucose concentration observed with high dietary fibre diets. Because fasting blood glucose is related to hepatic glucose production, we have tested the effect of propionate and acetate on hepatic glucose production. SETTING: The study was carried out in the Clinical Research Center for Human Nutrition. SUBJECTS: Six healthy young volunteers. INTERVENTIONS: The subjects received, in a random order: acetate (12 mmol/h), or propionate (4 mmol/h), or acetate+propionate (12 mmol/h + 4 mmol/h), or an isotonic sodium salt solution (saline) in 3 h gastric infusions. Blood glucose and plasma insulin was monitored. Hepatic glucose production was measured with an isotopic method using [6,6-2H2] glucose. RESULTS: No changes were observed in blood glucose, plasma insulin concentrations or hepatic glucose production with any of the infused solutions. An increase in free fatty acid (FFA) plasma concentration related to the fasting state was observed with the saline solution, but not with the SCFA infusions (P < 0.05). There was also an increase in beta-hydroxybutyrate concentration with the saline and the acetate solutions, but not with the propionate or acetate+propionate solutions. CONCLUSIONS: SCFA, administered at a rate calculated on the basis of a continuous daily fermentation of 30 g dietary fibres, do not change hepatic glucose production or fasting blood glucose. Propionate and acetate decrease plasma FFA, and further studies are needed to explore this effect on glucose tolerance and insulin sensitivity.

Acetates↗
PubMed1995

[Multiple bronchial artery aneurysms in a patient with silicosis].

We report a case of haemoptysis in a long-standing silicotic in whom arteriography revealed saccular aneurysms of the bronchial arteries. Embolisation was satisfactory in excluding the aneurysms and leading to a favourable outcome. The mechanism of the formation of these aneurysms which is extremely rare was discussed with reference to the few reports and literature.

Aged↗
PubMed1995

[Palliative percutaneous treatment under x-ray computed tomographic control of inoperable pulmonary aspergilloma. Apropos of 30 cases].

The authors report 30 cases of the percutaneous treatment of symptomatic pulmonary aspergilloma by injection of amphotericine paste in patients who were not considered to be operable. The treated aspergillomas had developed as a sequel to bacilliary infection and pulmonary fibrosis. Surgery was contraindicated in these patients on account of severe respiratory failure. The authors specify the technique for the preparation of the paste and for the type of percutaneous injection, the aim being to obtain complete filling of the cavity and creating an anaerobic environment for the aspergillus. The contribution of this technique for the non-surgical treatment of patients appears interesting but should be carried on a larger series to identify the exact indications and the interaction with other new treatments which have just appeared.

Aged↗
PubMed1994

Minimal model for determination of insulin sensitivity: repeatability in control and obese subjects.

A mathematical model was recently developed (minimal model) to estimate insulin sensitivity from the analysis of blood glucose and insulin concentration after a modified intravenous glucose tolerance test. This approach was successfully compared with the euglycemic glucose clamp in humans. In this study, we have analysed the distribution and reproducibility of this method in 10 healthy subjects and seven obese patients. We have observed a lower insulin sensitivity (SI) in obese patients (1.96 +/- 0.38 x 10(-4)/min/microU/ml) than in healthy subjects (8.19 +/- 1.16 x 10(-4)/min/microU/ml) with a small overlap between the two groups. The test was repeated twice and good repeatability was found with the method of Blank and Altman when a log transformation was applied to the data.

Adult↗
PubMed1994

[Discovery of an insulinoma during the first trimester of pregnancy].

Insulinoma is a rare tumour reported in 10 cases during pregnancy. In most cases, hypoglycaemia occurred during the first trimester and no fetal malformations were noted. We report a new clinical case of insulinoma diagnosed at 6 weeks of amenorrhoea in a 25-year-old woman. Surgery performed at 17 weeks of amenorrhoea confirmed the presence of a 7 mm diameter endocrine tumour in the head of the pancreas and led to a cure. The pregnancy continued without complications, and at 35 weeks the patient gave birth to a 3.5 kg infant with no malformation. This case was investigated in terms of a possible physiopathological cause of insulinoma during pregnancy. There is good evidence that insulin secretion increases rapidly from the beginning of pregnancy because of beta-cell proliferation and enhanced beta-cell sensitivity to glucose stimulus as a result of hormonal changes, i.e., prolactin and/or placental lactogen secretion. Moreover, some studies have suggested that insulin sensitivity is enhanced during early pregnancy. Taken together, these phenomena may explain why insulinoma occurs early during pregnancy. Although repeated hypoglycaemia has caused teratogenic effects in animal models, no fetal malformation has been described in previous reports of insulinoma during pregnancy, whether cured or not. This is in agreement with prospective studies in insulin-treated pregnant diabetic women showing no correlation between hypoglycaemia and malformations. These results are encouraging with respect to such pregnancies which, however, require careful supervision.

Adult↗
PubMed1994

Measurement of whole body acetate turnover in healthy subjects with stable isotopes.

Colonic fermentation of dietary fibres produces short-chain fatty acids (e.g. acetate, propionate). Measurements of whole body acetate turnover was used in order to estimate the production of colonic short-chain fatty acids in human subjects. However, higher flux rates for acetate have been reported in human studies with stable isotopes as compared to radioactive tracers. The reasons for this discrepancy are unclear. In this study, the stable isotope (1-13C)acetate was used and a method was developed to measure its enrichment in plasma. Variations between and within assays were less than 5%. The standard curve was linear from 0.5% to 10% enrichment. When this tracer was infused for 160 min in six healthy volunteers, acetate turnover was found to be 7.5 +/- 1 mumol kg-1 min-1, which is similar to data reported with radioactive tracers. We assumed that the higher flux rate previously observed with stable isotope tracers was related to differences in the physiological status of the subjects involved in these studies.

Acetates↗
PubMed1994

Rate of [15N]leucine incorporation and determination of nitrogenous fractions from gastro-jejunal secretion in fasting humans.

The aim of this study was to quantify the nitrogen fraction flow rates in gastro-jejunal secretions in fasting humans and to determine the [15N]leucine incorporation into the secreted proteins. A double lumen intestinal perfusion method was used in 5 healthy volunteers. Plasma and gastro-jejunal juices were collected during a 15-h intravenous [15N]leucine infusion. Total, soluble and insoluble nitrogen, amino acids and [15N]leucine enrichment were measured. The total nitrogen flow rate was 7.2 +/- 1.9 mmol.h-1 and 58% was ethanol soluble. The amino-acid composition remained constant and glycine was the most abundant. The plasma [15N]leucine enrichment at the isotopic plateau was 4.8 +/- 0.9 mol% excess. The [15N]leucine enrichment in the intestinal chyme increased asymptotically to reach a plateau after 5 h. The [15N]leucine enrichment at the plateau and the fractional synthesis rate of secreted proteins were 1.6 +/- 0.5 mol% excess and 21.5 +/- 3.3%.h-1, respectively. These results show that the composition of the basal gastro-jejunal secretion is very stable. A part of this secretion is composed of proteins with rapid synthesis rates.

Adult↗
PubMed1994

Comparative study of the acute effects of resistant starch and dietary fibers on metabolic indexes in men.

The effect of ingestion of the same amount (30 g) of a resistant starch (lintner) and cellulose on energy expenditure (EE), colonic fermentation (breath-hydrogen test), and blood glucose, insulin, and free fatty acid (FFA) concentrations were compared in seven healthy volunteers in a first experiment. In a second experiment the same indexes were measured in six healthy volunteers after the ingestion of diets composed of 50 g glucose alone or mixed with 30 g lintner, or cellulose, or pectin. In the first experiment no differences between lintner and cellulose were observed on the measured indexes. The notable difference was the increased apparent colonic fermentation with lintner after 6 h. In experiment 2, although insulin response was significantly lower in the pectin-added diet, the results obtained with the four different diets were not significantly different. The metabolic characteristics of lintner were closer to cellulose than to pectin. In conclusion, the acute effect of the ingestion of a resistant starch (lintner) on the measured metabolic indexes is similar to that of a known insoluble fiber--cellulose.

Adult↗
PubMed1994

Role of viscous guar gums in lowering the glycemic response after a solid meal.

The aim of the present study was to investigate how guar gum viscosity acts on starch digestion and glucose absorption in humans. Six healthy subjects received a mixed diet composed of 60.4% carbohydrate in the form of maize glucose or pregelatinized starch, to which was added 5.6% low- or high-viscosity guar gums. Meals were ingested or instilled in the duodenum and postprandial insulin and glucose responses were monitored for 3 h. Infusion of meals containing glucose showed that the delay in the diffusion rate to the duodenal mucosa due to bolus viscosity was not significant. Infusion of meals containing starch showed that a decrease in the digestion rate of starch in the upper small intestine accounted for part of the effect of viscosity on glycemic response, whereas the main effect of guar gum was apparently to slow gastric emptying.

Adult↗
PubMed1993

[Current data on the physiopathology of massive obesity].

It is now believed that the factors leading to massive obesity are a caricature of those which are responsible for common obesity. The lipid component of daily diet is as important as the amount of calories ingested. Putting on weight occurs only in subjects with metabolic abnormalities or with genetically determined neuro-hormonal anomalies. The weight increase tends to correct the initial metabolic disturbances, and in fact obesity is nothing but a phenomenon of adaptation. The development of molecular biology techniques should help us, in the near future, to understand these major physiopathological disorders.

Adult↗
PubMed1993

Effects of colonic fermentation on respiratory gas exchanges following a glucose load in man.

Colonic fermentation produces short-chain fatty acids (SCFA). In humans, the amount of energy produced from the oxidation of these compounds is unknown and could modify the metabolic utilization of energetic fuels (eg, carbohydrates and lipids). If it were so, the equations used to evaluate the oxidation of nutrients from indirect calorimetry data should include the contribution of SCFA, which is not usually the case. Indeed, this fermentation process is usually considered as a minor and neglected energetic pathway. In this study, we have addressed the reliability of this assumption. Six normal subjects received orally either 50 g glucose or 50 g glucose plus 20 g lactulose. Their respiratory gas exchanges, breath hydrogen, methane, and 13CO2 concentrations, and plasma glucose, insulin, and free fatty acid (FFA) concentrations were monitored for 8 hours. CO2 production and breath hydrogen concentration were significantly greater with lactulose. No differences in oxygen consumption, breath 13CO2 production, or plasma concentrations of blood glucose, FFA, and insulin could be found between the two experiments. This suggests that the fermentation process induced by lactulose generates extra fuels going through an oxidation pathway. Therefore, the classic equations used to calculate carbohydrate and lipid oxidation and energy expenditure (EE) from indirect calorimetry data are probably not valid when fermentation is taking place. Indeed, in this experiment we could have overestimated glucose oxidation (12.5%) if the fermentation process were not considered. In conclusion, colonic fermentation in humans of nondigestible carbohydrates produces energetic substrates that could be used and oxidized as energetic fuels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

An isotopic study of the effect of dietary carbohydrate on the metabolic fate of dietary leucine and phenylalanine.

The fate of dietary leucine and phenylalanine was studied in five healthy, young adult men, by using a dual, stable isotope-tracer infusion approach to estimate amino acid fluxes, splanchnic (Sp) uptake, and dietary of absorbed amino acid to the peripheral circulation. Subject received two, 4-h tracer infusions of [1-13C]leucine and [15N]phenylalanine infused through a feeding tube placed in the duodenum, and [5,5,5-2H3]leucine, [ring-2H5]phenylalanine, and [6,6-2H2]glucose infused simultaneously by vein. In one experiment subjects received an amino acid mixture (83 mg amino acid.kg-1.h-1) via the feeding tube and in the other experiment amino acids were supplied with carbohydrate (CHO) (167 mg.kg-1.h-1). Sp uptake of dietary leucine decreased with added dietary CHO (29% of ingested leucine for amino acids alone vs 20% with CHO; P < 0.05) but was not different for phenylalanine (P > 0.05). Addition of CHO decreased both release of leucine via protein breakdown and leucine oxidation and increased body leucine balance (P < 0.05).

Adult↗
PubMed1993

Bronchoalveolar lavage phospholipid abnormalities in HIV-infected patients.

Our aim was to evaluate the quality of pulmonary surfactant, a nonspecific defence system, during the course of human immunodeficiency virus) infection. Protein and phospholipid composition were determined in 127 bronchoalveolar lavage (BAL) fluids from 89 HIV seropositive patients (54 acquired immune deficiency syndrome (AIDS), 35 non-AIDS) and 11 healthy controls. In all of the HIV BAL samples, biochemical abnormalities were found. In subjects with pulmonary infection or Kaposi's sarcoma, the phospholipid/protein ratio was decreased, mainly because of elevated protein levels (15.8 and 20, respectively, vs 7.2 mg.100 ml-1 for controls, p < 0.05). In subjects without obvious pulmonary involvement, phospholipid was decreased (1.3 +/- 0.2 vs 2.9 +/- 0.3 mg.100 ml-1 for controls, p < 0.001), whereas the protein was not altered. Phospholipid composition was also altered: the phosphatidylcholine percentage was decreased, whilst the other main phospholipids were increased. We conclude that the alveolar lining is altered, whatever the stage of HIV disease. In most patients, it results from an increase of vascular permeability, with an influx of serum proteins. However, changes in phospholipid composition suggest that, in some cases, surfactant is also altered.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Effect of a protein-sparing diet on responses to exercise in obese subjects.

We have studied muscular work efficiency and VO2 peak in seven obese individuals (body mass index: 38.9 +/- 5.8 kg.m-2) before and after twelve days of a low-caloric diet (protein-sparing modified fast) providing about 2460 kJ/day. Respiratory gas exchanges were measured at rest and during an exercise protocol through a rubber mask connected to a pneumotachograph and a mass spectrometer. A significant reduction in body mass was observed with the diet therapy (109 +/- 12 vs 105 +/- 14 kg; p < 0.02). No significant differences were observed in VO2 peak (1.78 +/- 0.32 vs 1.88 +/- 0.43 l/min, p > 0.05) and work efficiency (26 +/- 5 vs 24 +/- 4%, p > 0.05), after the diet protocol. It is concluded that the low-caloric diet used had no effect on muscular work efficiency.

Adolescent↗