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F Belleville

Publications and source records attributed to F Belleville.

At least 37 records · Page 2Linked to original sources
PubMed1995

Role of the kidney in the production of a low molecular weight growth factor (MW < 1000 Da): experimental study in the pig.

Small peptide molecules known as low molecular weight growth factor (LMW-GF) have been identified in human serum. They enhance the effect of IGF-1 (insulin-like growth factor) on proteoglycan synthesis. In the present work we investigated the role played by the kidney in the production of LMW-GF, using the pig as an experimental model. Six pigs underwent bilateral nephrectomy followed 24 h later by orthotopic autotransplantation of the kidney. Renal and liver functions were evaluated by measurement of serum creatinine, urea, electrolytes, amino transferases (ASAT, ALAT), proteins, and bilirubin. LMW-GF was measured by bioassay using 11-day-old pelvic chick embryo cartilages. We observed that LMW-GF quickly disappeared from pig serum after nephrectomy and only reappeared when transplantation was successful. Reappearance of LMW-GF can precede improvement of renal function evaluated by plasma creatinine levels. These data appear to demonstrate that the kidney is involved in LMW-GF production.

Acute Kidney Injury↗
PubMed1994

Effect of L-carnitine and acylcarnitine derivatives on the proliferation and monoclonal antibody production of mouse hybridoma cells in culture.

The effect of L-carnitine (Cn) on cell growth metabolism and antibody production rates was investigated using the murine hybridoma cell line, Mark3, in batch and fed harvest cultures. Two acylcarnitine derivatives were also tested: palmitoyl L-Cn and acetyl-DL-Cn. The addition of 20 microM L-Cn to cultures of Mark3 hybridoma cells that had been adapted to L-Cn significantly stimulated monoclonal antibody (mAb) production without affecting cell growth. In contrast, mAb secretion slightly decreased when L-Cn was added to culture of cells that had not been adapted to L-Cn. Palmitoyl L-Cn also stimulated mAb production by adapted cells, whereas the acetyl-DL-Cn, reduced mAb secretion. The presence of L-Cn in the medium did not affect glucose consumption or lactate production, but the metabolism of some amino acids was altered. The medium concentrations of valine, leucine, isoleucine and lysine were enhanced from 22% to 41% according to amino acids, whereas those of alanine, glycine and proline decreased. The mechanism by which L-carnitine affects mAb production and the metabolism of some amino acids is unknown. This effect is likely to be indirect, since there was no net entry of L-[3H]carnitine into the cells.

Acylation↗
PubMed1993

Quantification of methylmalonic acid in serum measured by capillary gas chromatography-mass spectrometry as tert.-butyldimethylsilyl derivatives.

Quantification of methylmalonic acid in serum is considered one of the most sensitive parameters for diagnosis of cobalamin deficiency. Methylmalonic acid was measured as tert.-butyldimethylsilyl derivatives formed in the presence of dimethylformamide. Under these conditions the derivative was quantified using gas chromatography-mass spectrometry with selected-ion monitoring at 403 and 406 for methylmalonic acid and methyl-d3-malonic acid, respectively. The characteristics of the method were: linearity from 0.04 to 1.7 mumol/l with linear regression equation y = -0.0199 + 0.727 x (r = 0.999); recovery 95.5 +/- 6.8%; detection threshold 17 fmol injected; within-day variation coefficient ranging from 3.10% to 5.6% according to sample concentration; and day-to-day coefficient of variation of 6.8% and 5.3% for methylmalonic acid concentrations of 0.103 mumol/l and 0.360 mumol/l, respectively. The normal range after log transformation was estimated at 0.03-0.26 mumol/l, 0.06-0.33 mumol/l and 0.02-0.40 mumol/l in children of 4-14 years (n = 39), in healthy subjects at 20-40 years (n = 70) and in healthy elderly persons older than 60 years (n = 14), respectively. The normal range in children was significantly lower than that in adults and, in contrast, normal values in the elderly were significantly higher.

Adolescent↗
PubMed1993

Search for cell proliferation markers suitable for cell count in continuous immobilized cell bioreactors.

The control of hybridoma cell cultures in bioreactors requires the use of convenient indicators to monitor the proliferation of the biomass. In order to select appropriate indications, we followed the variations of several compounds including tumoral markers, polyamines, sialic acids, purine and pyrimidine bases, enzymes and metabolites such as glucose, lactate and amino acids, and the variations of cell density during batch culture. Significant correlations were found between the number of viable cells and alkaline phosphatase, beta-glucuronidase, glucose and lactate measured in the culture medium of hybridoma strains. The correlation calculated from alkaline phosphatase and beta-glucuronidase concentrations in culture medium underestimated cell number. The correlation established with glucose and lactate gave the best indication of cell proliferation in continuous culture with an immobilized cell bioreactor. Finally, the exact quantification of the biomass in these culture conditions can be obtained using the mean of glucose and lactate correlations.

Animals↗
PubMed1993

Role of the kidney in the expression of low molecular weight factors with growth factor activity.

Small molecules of peptidic nature, called low molecular weight growth factors (LMW-GF < 1000 Da) are present in normal human serum ultrafiltrate. They enhance the somatomedin activity as measured by the incorporation of 35SO4 into chick embryo cartilages. On the basis of this in vitro test, LMW-GF activities were measured in serum ultrafiltrates of hemodialyzed patients and renal transplant recipients during the post-transplantation follow-up. LMW-GF activity was always zero in patients with chronic renal failure. It was checked that these results were not due to the presence of low molecular weight somatomedin inhibitors or to the increased sulfate concentration. After successful renal transplantation, the LMW-GF activity of patients ultrafiltrates returned to normal at the same time or before the improvement of renal function. In case of post-transplant complications, a decrease in LMW-GF activity accompanied or even occurred prior to impairment of renal function. In functioning graft, LMW-GF activity reappears rapidly, whereas its normalization is delayed in case of tubular nephropathy or episode of acute rejection. It was suggested that the kidney is involved in LMW-GF molecules production or processing. It could be speculated that LMW-GF activity might be a prognostic factor in renal transplantation.

Adult↗
PubMed1992

[L-carnitine: metabolism, functions and value in pathology].

Although L-carnitine is not considered as an essential nutrient, endogenous synthesis may fail to ensure adequate L-carnitine levels in neonates, especially those born prematurely. Free L-carnitine is found in many foods, mainly those from animal sources. Absorption of free L-carnitine is virtually complete. Lysine and methionine are necessary ingredients for the biosynthesis of L-carnitine. All tissues in the body can produce deoxy-carnitine but, in humans, the enzyme that enables hydroxylation of deoxy-carnitine to carnitine is found only in the liver, brain and kidneys. Complex exchanges of carnitine and its precursors occur between tissues. Muscles take up carnitine from the bloodstream and contain most of the body carnitine stores. L-carnitine and L-carnitine esters are eliminated mainly through the kidneys, which may play a central role in the homeostasis of this compound. Thyroid hormones adrenocorticotrophin (ACTH), and diet all influence urinary excretion of L-carnitine. Free L-carnitine can be assayed in plasma and urine and is occasionally measured in muscle biopsy specimens. Plasma L-carnitine levels may not accurately reflect L-carnitine body stores. L-carnitine ensures transfer of fatty acids to the mitochondria where they undergo oxidation. This process is associated with production of short-chain acylcarnitine which exit from the mitochondria or peroxisomes. L-carnitine ensures regeneration of coenzyme A and is thus involved in energy metabolism. L-carnitine also ensures elimination of xenobiotic substances. Carnitine deficiencies are common. Currently, these deficiencies are classified into two groups. In deficiencies with myopathy, only the muscles are deficient in L-carnitine, perhaps as a result of a primary anomaly of the L-carnitine transport system in muscles. In systemic deficiencies, L-carnitine levels are low in the plasma and in all body tissues. Systemic L-carnitine deficiencies are usually the result of a variety of disease states including deficient intake in premature infants or long-term parenteral nutrition; renal failure; organic acidemias; and Reye's syndrome. Modifications in L-carnitine metabolism have also been reported in patients with diabetes mellitus, malignancies, myocardial ischemia, and alcohol abuse. A large number of supplementation trials have been carried out.

Adolescent↗
PubMed1991

[Chromium: physiologic role and implications in human pathology].

Reported values for total body stores of chromium vary between 0.4 mg and 6 mg. Chromium stores may be higher in neonates than in adults, relative to body size, whereas tissular chromium may be depleted in the elderly. The recommended daily allowance for chromium is 50 to 200 micrograms/day but actual needs are poorly known. Digestive absorption is better for organic chromium, which is part of the "glucose tolerance factor" (GTF), than for inorganic chromium. Furthermore, chromium (VI) is better absorbed than chromium (III). In the body, chromium (VI) is rapidly reduced to chromium (III) by a number of metabolic pathways. Absorbed chromium binds to proteins, mainly to transferrin which exhibits a high affinity for chromium (III). Most absorbed chromium is eliminated through the kidneys. Renal excretion occurs according to a two or more-compartment model. Current methods used to assay chromium, i.e., atomic absorption spectrometry using a graphite furnace or neutron activation, are sufficiently sensitive and specific to evaluate chromium levels in blood, urine or hair. However, none of these levels accurately reflects chromium body stores. Chromium is part of the GTF molecule. This factor has no effect per se but may facilitate binding of insulin to insulin receptors and amplify the effects of insulin on carbohydrate and lipid metabolism. Chromium deficiency may play a role in a development of some forms of adult diabetes mellitus and of arteriosclerosis. Partial chromium deficiencies seem to be common, especially in individuals with high intakes of refined foods. Acute chromium poisoning is usually due to an excess of chromium (VI) and is sometimes seen in the chromium industry.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Application of preparative high-performance liquid chromatography to the purification of a fetal ovine insulin-like growth factor II: N-terminal sequence determinations using two different carriers.

A highly efficient procedure for the purification to homogeneity of an ovine fetal insulin-like growth factor II (IGF II) is described. Fetal sheep serum was used as the source material, and the bioactivity was followed throughout purification by an IGF II radioreceptor assay. Ovine IGF II was isolated by a combination of gel permeation, ion-exchange chromatography and reversed-phase high-performance liquid chromatography. The amino-terminal sequence of the first 36 amino acid residues was compared using two supports (polyethylenimine and polybrene) as carrier for protein sequencing. Ovine fetal IGF II was found to differ from human IGF II in three residues of the C-domain, with serine, isoleucine and asparagine substituted for alanine, valine and serine, respectively, at positions 32, 35 and 36. The final yield of highly purified ovine fetal IGF II was 134 micrograms, starting from 450 ml of serum.

Amino Acid Sequence↗
PubMed1990

Purification and characterization of three molecular forms of insulin-like growth factor II from human Cohn paste IV.

The somatomedins or insulin-like growth factors (IGFs) are a family of peptides present in human serum. They are bound to specific carrier proteins and are thought to mediate growth-promoting actions of human growth hormone. Starting from Cohn fraction IV of human plasma, we describe here a rapid and highly efficient procedure for the purification to homogeneity, in addition to IGF I. of three forms of insulin-like growth factor II: IGF IIA (10-12 kDa), IGF IIB (the "classical" 7.5 kDa IGF II) and IGF IIC, identified as the IGF II variant of Jansen by fast-atom bombardment mass spectrometry. The procedure is based on ion-exchange chromatography and gel permeation chromatography on Biogel P10. As judged by specific radioimmunoassay methods for IGF I and IGF II, one of the most striking advantages of this process at this stage is the yield of IGF I not contaminated by 7.5 kDa IGF II. Isoelectric focusing or chromatofocusing, which require affinity chromatography to separate proteins from the polybuffers, are not necessary in this procedure. Final purification was directly achieved by preparative, followed by analytical high-performance liquid chromatography. The N-terminal sequence of peptide IGF IIB (39 amino acids) and peptide IGF I (29 amino acids) showed total homology with those previously described by Rinderknecht and Humbel [FEBS Lett., 89 (1978) 283]. The final yields of purified human IGF I and IGF IIB were 15 and 25 micrograms, respectively, from 11 of serum. All peptides interact with specific receptors on human lymphocytes and red blood cells, and are biologically active (stimulation of 35S uptake, increasing [3H]thymidine incorporation in human and chick embryo fibroblasts).

Amino Acids↗
PubMed1990

[Cerebrospinal fluid amino acids in Alzheimer's disease].

Twenty-two amino acids are measured in cerebrospinal fluid of fourty patients with senile dementia of the Alzheimer type (SDAT) and of ten age matched healthy control subjects. There is no significant difference between these two groups.

Aged↗
PubMed1990

[Respective roles of high and low molecular weight serum growth factors in the metabolism of proteoglycans and other cartilage macromolecules].

35S radiolabeling allowed an evaluation to be made of neosynthesized macromolecules in chick embryo cartilage cultures. Activities for growth factors of high (serum retentate) or low (ultrafiltrate below 1,000) molecular weight (MW) were assessed in pelvic cartilage explants and in corresponding incubation media. In the absence of growth factor, 35S was mostly incorporated in glycosaminoglycans (GAGs) as regards the medium and for cartilage, in guanidinium chloride unextractable material. In retentate-enriched medium, 35S incorporation was enhanced in all cartilage GAGs while in the medium, stimulation essentially occurred in macromolecules other than GAGs. Low MW growth factors exclusively enhanced cartilage levels of macromolecules which were insoluble in guanidinium chloride. In the medium, these factors did not display any significant effect. These results indicate that human serum growth factors with high and low MW possess different metabolic targets at the cellular level.

Animals↗
PubMed1990

[Common values of serum selenium in a population in Eastern France].

Eastern France is a low selenium area. Livestock grazing on this soil had low selenium concentration. In human adults, the serum selenium levels were 0.91 +/- 0.14 mumol/l (n = 125) lower than in other european countries except Finland and Greece. However, no adult had serum concentration less than 0.57 mumol/l, a value under which the risk of death from ischemic heart disease or from cancer seem be increased. In infants, serum selenium contents were low, they increased progressively and reached adult levels at about 4 years in our study. In elderly subjects above 70 years old, serum selenium values were significantly (p less than 0.0001) below those of adults (0.83 +/- 0.17 mumol/l). The selenium values diminished when age increases in this population. 4.5 per cent of these subjects had a level under 0.57 mumol/l.

Adolescent↗
PubMed1989

Improved long-term storage of hybridomas at -80 degrees C using a bovine milk derivative.

A medium comprising 40% bovine milk fraction and 10% DMSO (medium A) was used for the long-term storage of hybridomas at -80 degrees C. The viability of the cells, their growth recovery and ability to secrete antibody were studied and the results were compared to those obtained after storage in a medium containing 40% fetal calf serum and 10% of DMSO (medium B). Hybridomas have been kept for 2 years in medium A; the viability of such cells was 75%, the cells were healthy (electron microscopy), they rapidly proliferated when they were cultured in RPMI supplemented with 10% FCS or with 9% milk fraction + 1% FCS and they released measurable levels of antibody. In contrast, hybridomas stored under the same conditions but in medium B died after 6 months.

Animals↗
PubMed1988

Serum iron and transferrin during an exhaustive session of interval training.

Conflicting data have been reported on "sports anaemia" and anaemia during physical training. Most of these results are of studies at rest before or after training. The aim of this investigation was to further study the profiles of serum iron (Se Fe) and transferrin (Se Tr), in 14 physically trained men (28 +/- 6 years) during an exhaustive interval training session. The 45 min Square-Wave Endurance Exercise Test (SWEET) was performed on a cycle ergometer. To the SWEET base, established as a % of individual VO2max, a peak of 1 min at VO2max was added every 5 minutes. Arterial blood samples were taken at rest, during the SWEET at the 14th, 15th, 29th, 30th, 44th and 45th minutes, just before and after the peaks, and at the 15th min of recovery. Lactate, acidity [H+], PaCO2, PaO2, Haematocrit (Hct), Haemoglobin (Hb), Se Fe and Se Tr were measured. After the SWEET, weight loss was 0.89 +/- 0.15 kg. Lactate and serum iron rose progressively at the base levels and at the peaks, while PaCO2 and bicarbonate fell progressively. Hct, [Hb], serum transferrin and [H+] increased significantly at the 14th min of SWEET and thereafter no change was observed. At the 45th min with respect to the value at rest, Se Fe increased as much as +32%, Se Tr +13% and [Hb] +8%. Haemoconcentration could explain the changes in Se Tr but not the total significant increase in Se, Fe, which moreover is not explained by acidosis [H+].(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Experimental conditions of a technic of in vitro transcription using placental nuclei].

To examine the expression of human placental lactogen, we investigated transcription in isolated placental nuclei. Using SH-agarose affinity chromatography, we have isolated Hg-RNA synthetized in vitro. These RNA are translated in a wheat germ cell-free system. hPL synthetized in vitro, accounting for 20% of total protein. This system should prove useful for the study of gene expression of hPL.

Female↗
PubMed1988

[Selenium: physiologic role and value in human pathology].

Selenium (Se) is a metalloid with chemical properties closed to those of sulfur, but they can not substitute for one another in vivo. Se body content reflected soil Se content (13 to 20 mg in North Americans, 3 to 6 in New Zealand residents). The daily intake recommended is 50 to 200 micrograms. In the diet Se occurs in mineral or organic forms, the bioavailability of these latter is better. Se as selenocysteine is incorporated in specific proteins such as glutathione peroxidase (GSH-Px). Se is metabolized in H2Se by reductive pathways. H2Se is methylated and methylated compounds are excreted in the urines. The Se urinary excretion represents the principal known process of Se regulation. Se bound to GSH-Px participates to free radical destruction and cellular membrane protection. Its role is complementary of vitamin E effect. Se also seems indispensable to appropriate immune response. It can chelate various metals allowing their detoxication. Se metabolism can be studied by Se assay in serum, whole blood, urine (reference values must be performed for each studied population) and by GSH-Px activity determination in erythrocytes or platelets. Vitamin E assay completes estimation of the antioxidative status of organism. Few Se intoxications have been recognized but Se deficiencies often happen. They can lead to a cardiomyopathy (Keshan disease), increase the risk of cardiovascular diseases or cancer. Se deficiencies are found in chronic renal failure, malnutrition malabsorption, long term parenteral nutrition. At the present time it is not known how Se deficiency interfers with chronic infections which often go with these diseases. A better knowledge of Se requirements and Se role could allow an appropriate supplementation in various diseases.

Animals↗