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Biomedical subjects

F Belleville

Publications and source records attributed to F Belleville.

At least 55 records · Page 3Linked to original sources
PubMed1987

Isolation and characterization of a low molecular weight growth-promoting factor from human plasma.

A low molecular weight growth factor (LMW-GF) enriched preparation was purified from human plasma after ultrafiltration or gel filtration by means of molecular sieving chromatography low pressure reversed phase chromatography (LP-RPLC) and electrophoresis. Purification was monitored by a biological assay testing the capacity of the fractions to enhance the sulfation activity of the somatomedins/insulin-like growth factors on chick embryo cartilage. Analysis of its chemical nature show that it is hydrophilic, stable to heat, resistant to most of the proteases but that it is degraded by acid hydrolysis or carboxypeptidase Y action. UV absorption spectrum and ion-exchange chromatographic retention behavior support the hypothesis that the most purified active preparation includes a peptide structure. The presence of sugar is suggested by concanavalin A binding experiments. The fact that the purification fractions also enhance thymidine uptake by other cell lines (fibroblasts, activated lymphocytes) widens the role of such small plasma molecules in the field of growth factor activities.

Animals↗
PubMed1987

Liquid chromatographic determination of cyclosporin A in serum with use of a solid-phase extraction. Comparison between high-performance liquid chromatography and radioimmunoassay levels in clinical investigations.

A simple reliable liquid chromatographic method for assay of cyclosporin A in serum or urine is described. Samples were cleaned up on a solid-phase extraction system (cyanopropyl column). The system involved a reversed-phase C18 Ultrasphere column maintained at 72 degrees C and an acetonitrile linear gradient (65 to 95%) in 0.14% triethylammonium phosphate. Liquid chromatographic analysis of radioimmunoassay standards shows that some samples contain a contaminant peak. Comparison of cyclosporin A levels obtained by radioimmunoassay and high-performance liquid chromatography in clinical investigations show that the former values are generally, but not always, higher than the latter, and that cyclosporin A is very differently metabolized depending on the patient, disease and treatment.

Adolescent↗
PubMed1987

[Sulfation and mitogenic activities of growth factors in human serum: importance of compounds of molecular weight lower than 1,000 in the global expression of activity of this serum on 3 different cellular types].

A human serum ultrafiltrate contains compounds needed for a maximal expression of sulfation and mitogenic activities of the corresponding retentate. These low molecular weight (less than 1,000) molecules have no effect, by their own, on 35SO4(2-) uptake in chick embryo cartilage, but show a significant synergistic effect with serum growth polypeptides. Tested alone, they display a slight mitogenic activity as measured by 3H-thymidine incorporation in chick embryo fibroblasts or in lymphocytes activated by phytohemagglutinin. Here they also act in a synergistic way on mitogenic activities of growth factors from human retentate. A fraction (P2B), partially purified from human plasma ultrafiltrates, produces the same synergistic response with human retentate in the three cellular systems (cartilages, fibroblasts, activated lymphocytes). However, concentrations which lead to optimum responses are very different according to the cell type studied. These results suggest the existence of several compounds which can each act specifically on a cellular system.

Cartilage↗
PubMed1984

The biological assay of human somatomedin A: improvement by small molecular weight natural molecules.

Somatomedin activity is often measured by 35SO4 uptake in pelvic chick embryo cartilage. This assay gives good results when the somatomedin activity is measured in serum, but often gives uninterpretable results for purified somatomedin. An ultrafiltrate (UF 1000) obtained from human normal serum, added to the incubation medium allows measurement of biological somatomedin activity even when somatomedin is highly purified. UF 1000 contains some compounds of molecular weight lower than 1000 daltons. UF 1000 acts either when used simultaneously with somatomedin or in pre-incubation with cartilage before testing biological activity. So, we chose to use it in pre-incubation (1 h) at the optimal concentration of 10% (v/v), the standard curves being realized with normal serum retentates . In these conditions, the proper action of UF 1000 does not interfere with calculation of somatomedin activity. This method has enabled us to show that a diminution of serum somatomedin activity can be linked either to an anomaly of UF 1000 or to a somatomedin deficiency.

Animals↗
PubMed1983

Determination of free and total polyamines in human serum and urine by ion-pairing high-performance liquid chromatography using a radial compression module. Application to blood polyamine determination in cancer patients treated or not treated with an ornithine decarboxylase inhibitor.

A sensitive and rapid determination of free and total polyamines (putrescine, cadaverine, spermidine and spermine) in urine and serum is described. The procedure is based on reversed-phase high-performance liquid chromatographic separation using radial compression module (Radialpak C 8). The samples are purified with a silica gel Sep-Pak cartridge. The polyamines are converted to dansyl chloride derivatives and separated using a linear gradient of triethylammonium phosphate-methanol within 15 min. The lower limits of detection are 10 pmoles for spermine and 5 pmoles for other polyamines. This method is applied to cancer patients treated by cytotoxic chemotherapy with or without difluoromethylornithine (DFMO). All four polyamines are significantly increased in these patients before treatment. On day 8, after onset of treatment, the levels of polyamines in patients not treated with DFMO are more elevated than on day 1, while in patients treated with DFMO the levels are decreased. However, DFMO does not seem to modify the treatment result. The patients which have a low level of putrescine before and during treatment, do not respond to treatment. Perhaps this low level is the consequence of conjugation of this polyamine?

Aged↗
PubMed1983

[Effect of somatomedin A and its serum cofactor on human fibroblasts in culture. Relation between mitogenic activity and effects on the biosynthesis of collagen and other proteins].

It was demonstrated in a previous paper that the sulfation activity of somatomedin A (SM-A) depends on the presence of a low molecular weight cofactor (CoF) present in human serum. In this paper, the effects of the two factors on human dermis fibroblast proliferation and syntheses of proteins and collagen were studied. The addition of SM-A alone to the culture medium had no mitogenic effect but modified the distribution of newly synthesized proteins, since 14C-proline incorporation was increased into proteins of the cell layer and decreased into proteins of the medium. The addition of CoF alone had no significant effect. Simultaneous addition of SM-A and CoF restarted cell divisions and increased the inhibiting activity of SM-A on the secretion of proteins into cell supernatant.

Cell Cycle↗
PubMed1981

[Preparation of nuclei from human placenta].

The authors describe a method of isolation and purification of nuclei from human placenta. The use of an homogenization containing divalent cations, an homogeneization method using a stepwise procedure, allow us to obtain nuclei free of cytoplasmic contaminants. Electronic microscopy shows that the material has kept morphological aspects of the nuclei of fresh tissue and these nuclei have kept an transcriptional activity.

Cell Fractionation↗
PubMed1981

[Isolation of various fractions of human placental nuclei and their utilization in an in vitro transcription system].

A new approach to isolating chromatin and DNA from human placental nuclei is described. Criteria of purity are given by spectrophotometry and chemical analysis. Chromatin and DNA keep their template efficiencies after isolation. We used them in a transcription system where wheat germ RNA polymerase intervenes. The role of histones was tested on this system.

Cell Fractionation↗
PubMed1981

[Translation of mRNA extracted from human placenta in a wheat germ cell free system].

The mRNA were isolated from total RNA extracted from placenta by affinity chromatography on poly U Sepharose 4 B and were tested with wheat germ cell free system. The neosynthesized hPL is isolated by specific immunoprecipitation using 2 antibodies from the CEA (hPLK1 and hPLK3). It represented 7% of the total radioactive synthesized proteins. Two components were separated by gel electrophoresis. One is the natives hormone while the other which is the major component, migrated with a molecular weight of 25 000. These results are in accordance with a functionally cell free system which could be used study the non histone protein's role in the hPL synthesis.

Cell-Free System↗
PubMed1980

Determination of oxalates in plasma and urine using gas chromatography.

A gas-chromatographic procedure for the analysis of oxalic acid is described. The procedure requires relatively small quantities of urine (1 ml) or plasma (5 ml). The procedure consists of three steps: (1) extraction of exalic acid by acidified diethyl ether; (2) esterification by isopropanol; and (3) final analysis by gas chromatography. The oxalic acid was found to have an elution temperature of 107 degrees C and a retention time of 14 min. The standard curve is linear up to 800 nmol. In the described condition the lower limit of detection is 20 nmol. The mean normal plasma and urine oxalate levels (mean +/- 2 S.D.) were found to be 20 mumol/l +/- 17.5 and 275 mumol/24 h +/- 200 respectively.

Chromatography, Gas↗
PubMed1979

HCS regulation in cultured placenta: action of glucose.

The regulation of HCS secretion on placenta cultures in the presence of [3H] leucine was studied. When Eagle's medium containing 0.0055 M of glucose per liter is used, it is noted that the HCS increases regularly in the culture medium, whereas it diminishes in the explants. [3H] HCS represents about 50% of the [3H] proteins, and among these proteins HCS is preferentially secreted in the culture medium. The absence of glucose in the medium provokes a decrease in all of the cellular metabolism as well as a decrease in protein and HCS secretions, with an accumulation of preformed HCS in the tissues. An increase in the glucose level in the medium 0.011 and 0.027 M provokes a selective decrease of HCS secretion with an accumulation of preformed HCS in the tissues, determing a long term decrease in HCS synthesis. Insulin added in the mediums (60 microU/ml) does not change the results significantly. The use of structural analogues of the glucose shows that the point of impact of the HCS secretion regulation by the glucose is membranous; however, it seems that at a second stage one or some glucose metabolites also interven. There is no self regulation of HCS secretion in vitro.

Culture Media↗
PubMed1978

HCS-HCG regulation in cultured placenta.

Tissue culture has been used to study the action of different substrates on the secretion of HCG and HCS in human placental explants. The following compounds have been studied: prostaglandins E2 and F2alpha, adrenaline and noradrenaline, oestriol and progesterone, glucose concentration. The investigators first measured the normal secretion of three term placentas and 2 months placentas. The activity of the compounds tested is expressed in per cent of the normal values. The investigators have checked that the cultivated cells were always viable by measuring the oxygen consumption during all the experiments. PG E2 and F2alpha are without action on term placentas. Adrenaline and noradrenaline reduce significantly the secretion HCS by full term placentas and have no action on HCG secretion. Oestriol always stimulates HCS secretion by full term placentas and 2 months old placentas, whereas progesterone stimulates young placentas and inhibits full term placentas. Both steroids have no action on HCG secretion. Glucose is essential for HCS secretion by placentas but high values of glucose in the medium signficantly reduce the HCS secretion by full term placentas.

Cells, Cultured↗
PubMed1978

[Laron type familial dwarfism; genetic primary somatomedin deficiency].

Five children from 3 different families presented with severe dwarfism and the morphological and biological features described by Laron: familial occurrence, small stature, peculiar facies, high levels of plasma HGH and resistance to treatment by GH. This therapeutic inefficiency is expressed by an absence of physical growth and unchanged nitrogen balance, during a prolonged treatment. The plasma levels of somatomedine were very low (K. Hall's biological method) and not influenced by administration of exogenous HGH. These findings suggest that the fundamental disorder is not an abnormal structure of the molecules of GH. This hypothesis seems further confirmed by the structural analysis of plasma HGH, which gave the same results as those of the reference GH.

Child↗
PubMed1978

[beta2-Microglobulin and monoclonal gammapathies (author's transl)].

145 Determinations of beta2-microglobulin (beta2m) have been realized in 111 patients with a monoclonal gammapathy. The level of beta2m is significantly higher (p = 0,0001) in the group with monoclonal gammapathy (M = 4,75 mg/l +/- 5,62) than in normal subjects (M 1,38 mg/l +/- 0,38). In a group with monoclonal gammapathy with renal failure, the level of beta2m is higher (M = 7,07 mg/l +/- 7,76) than in a group with renal failure alone (M = 3,45 mg/l +/- 1,91). The difference is significant (p = 0,005). The level of beta2m is higher in IgA monoclonal gammapathies (M = 5,61 mg/l) than in IgG (M = 4,18 mg/l) or IgM (M = 4,37 mg/l) gammapathies, but the differences of the means between the three groups are not significant. The assay of beta-2m does not allow to distinguish myeloma (M = 3,18 mg/l +/- 1,83) from benign monoclonal gammapathy (M = 3,22 mg/l +/- 1,32) and is not useful when the diagnosis is difficult.

Beta-Globulins↗