Search PubMed⌕ Search

Biomedical subjects

P Paysant

Publications and source records attributed to P Paysant.

At least 19 recordsLinked to original sources
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↗
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↗
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↗
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↗
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↗
PubMed1977

[Glucose role in regulation of placental lactogen hormone (hPL) secretion].

The authors have studied the role of glucose on the excretion of hPL in the medium by explants of placenta in culture. 1. The glucose is necessary for this excretion and cannot be replaced by lactate. 2. At concentrations higher than 1.5 g/l, the glucose inhibits the excretion of hPL. 3. This inhibition is shown for long periods of action of the glucose (4 days) as well as for short periods (1, 2 and 4 hours).

Dose-Response Relationship, Drug↗
PubMed1977

[Circulating molecular forms of prolactin in the normal nursing mother and during tumoral amenorrhea-galactorrhea].

The authors have studied by gel chromatography and radioimmuno assay, the molecular forms of prolactine in the serum of normal lactating women and in serum of three subjects having an hypophyseal tumor. 1. In the normal women, one find two pics of prolactine : one migrating like the monomere (M.W. 20000), and the other as a trimere (M.W. : 60000). There is small amounts of a large molecule migrating in the dead volume of the column. 2. In the patients having a tumor, one find not only the monomere but also a large molecule (M.W. greater than 100000) which is the principal form in the serum. The results are compared with these of the literature.

Adenoma↗
PubMed1977

[Study of molecular forms of ovine and human prolactin].

After labelling of human and ovine prolactine by the lactoperoxydase method, each prolactine shows at least three molecular forms : amorphous aggregates of large molecular weight, one dimere (M.W. no. 50 000) and one monomere (M.W. no. 25 000). The monomere and the dimere can spontaneously give rise to the aggregates. But the dimere never give monomere and monomere never give dimere. Urea 8 M alone have not dissociating action on the polymeres or on the dimere. But urea 8 M plus mercaptoethanol transforms polymeres into dimeres and monomeres.

Animals↗
PubMed1976

[Study of a placental protein binding AMPc. Its subcellular distribution. Hypothesis of a relationship with chorionic somatommamotropin hormone].

The authors have shown the presence in the human placenta of a binding activity for cAMP. This activity is protein like substances bound and is principaly located in cytosol and in nucleus. The authors have tried to purified this protein by gel filtration and chromatography on DEAE cellulose. Whatever the method employed, there is always in the protein a mixed activity: cAMP binding activity and HCS immunological activity. Purified HCS by classical method shows no binding activity. However when cAMP is added in immunological system HCS-immun-serum anti-HCS, the reaction is modified in an inhibitory way. This behaviour seem to be specific since never HGH nor TSH have the same. This behaviour has been confirmed several times as well during competition curves which shift toward left in presence of cAMP, as for assays of individual serums or amniotic fluids. In this last cases, the results are twice as eleveted depending if the lecture is done on a curve done without cAMP or with cAMP.

Cytosol↗
PubMed1976

[Induction of N-acetyllactosamine synthetase activity in the mouse mammary gland by prolactin and placental lactogen hormone].

The authors show that the ovine prolactine promote induction of N. acetyl lactosamine synthetase in tissue culture of mammary glands of pregnant mice. A crude extract of human placenta has also a lactogenic activity as tested by the same method, but in this case the blank values are very high for large concentration of crude extract. The molecular forms of HCS are tested: the slow band has a lactogenic activity, the intermediate band has no activity and the rapid band seems to be inhibitory.

Animals↗
PubMed1976

[Molecular forms of human growth hormone (HGH) secreted by cultured fetal pituitary cells].

Cultures of foetal human pituitary cells excrete and synthetize different molecular forms of proteins with HGH immunological activity. These cells incorporate tritiated-leucine in these proteins. Gel chromatography on sephadex using different length of column allow us to separate: One form excluded in front of the dead volume and which has a high molecular weight. This form is not dissociated by treatment with urea 8 M, guanidine 6 M and dithiothreitol. Nor this form is modified by treatment by ribonuclease. One form excluded within the dead volume and which is probably a dimere. This form is no more modified by the different treatments. One form which is excluded like a monomere--it is the more important form--. This form is dissociated in fragments of lower molecular weight by urea 8 M. This dissociation is partially reversible by dialysis.

Cells, Cultured↗