PubMed Health⌕ Search

Biomedical subjects

H Gerard

Publications and source records attributed to H Gerard.

34 records · Page 2Linked to original sources
PubMed1988

Electron microscope radioautographic evidence of in vivo androgen-binding protein internalization in the rat epididymis principal cells.

The androgen-binding protein (ABP) has been purified from rat testes with a yield of 14% using four steps of HPLC and was subsequently iodinated to a specific activity of 0.1 mCi/mg protein. Using a micromanipulator, [125I] iodo-ABP-dihydrotestosterone was injected intraluminally into the proximal caput of the rat epididymis. Epididymides were sampled from 3 to 120 min after the injection of the tracer and processed for transmission electron microscopy autoradiography. Our results showed the accumulation of detectable radioactive sources in the apical cytoplasm of only one of the epithelial cell type lining the ductus, the principal cells. In the interval from 3 to 120 min, the iodinated ABP was mainly present in the supranuclear region and was especially concentrated over coated structures, endosomes, multivesicular bodies, and over the Golgi apparatus. The same pattern was obtained using [3H]dihydrotestosterone-ABP complex instead of iodinated ABP. In addition, there was a negative correlation between the log time and the distribution of the silver grains in the luminal border and in the compartment of the apical vesicles. On the contrary, there was a positive correlation between the log time and the distribution of the silver grains in the Golgi apparatus. These results provide, for the first time, direct histological evidence of the in vivo ABP internalization by the principal cells. Since horseradish peroxidase, a fluid-phase endocytosis marker, when injected under the same conditions was internalized in both apical and principal cells, since labeled radioactive ABP appeared to be bound to the membrane of the endocytic apparatus rather than to its content, and since this binding and uptake could be prevented in the presence of an excess of unlabeled ABP, it is concluded that the internalization of ABP could not be a nonspecific fluid-phase endocytosis but should be dependent on its interaction with the apical plasma membrane of the principal cell. It still remains to be determined if these mechanisms involve the binding of ABP to a specific membrane receptor.

Androgen-Binding Protein↗
PubMed1988

[Possibilities and limits of pronatalist policies in the Western world: possible fields of intervention and determinants of fertility].

"Two questions are discussed in this paper: (1) what are, according to theory, the possible fields of intervention if one wants to act on the determinants of fertility? (2) according to those theories which seem to be validated by empirical analysis, what are the main determinants of the present fertility trend, on which it would be necessary to act in order to stop the decline and obtain an upward movement? The author concludes that, according to the present state of knowledge, a pronatalist policy is out of reach, except as a mere experimental exercise." (SUMMARY IN ENG AND SPA)

Demography↗
PubMed1987

Modifications of the thymus and splenic thymic dependent zones after in utero exposure to phenytoin: qualitative and quantitative analysis in C3H mice.

Pregnant female mice were randomly distributed in two groups and received twice a day by gavage either 25 mg/kg Dilantin in 0.2 ml distilled water or 0.2 ml distilled water till full term. The offspring were sacrificed on day 5. In the exposed group, the thymic cortex was reduced with a low mitotic activity in the lymphoid population while reticuloepithelial tissue was enlarged; numerous interdigitated reticular cells accumulate at the cortico/medulla border. In the spleen, the white pulp was enlarged because of lymphocytes accumulation in the periarteriolar sheets. In these two organs, the relative number of Thyl-2+, Lyt 1+ and Lyt 2+ T cell subsets were also modified showing especially a decrease in the thymus and an increase in the spleen of the Lyt 1+ cells. Since at the same time the thymus and the spleen of the females which reproduced the neonates are quite unchanged, it is concluded that the developing immune system of the fetal mouse is more susceptible to diphenylhydantoin than the immune system of the adult. This raises the question of the reversibility of this in utero acquired immune impairment.

Animals↗
PubMed1986

Purification of androgen-binding protein from rat testis using high-performance liquid chromatography and physicochemical properties of the iodinated molecule.

The androgen-binding protein (ABP) has been purified 87,500-fold from rat testis using 4 steps of HPLC, with a yield of 14%. The molecule was 99% pure with a specific activity estimated to 16,600 pmol/mg protein. The iodinated molecule was eluted in 2 peaks in Sephacryl S300 gel filtration with a molecular mass estimated to be 92,600 +/- 3300 and 50,300 +/- 4000 Da. The column isoelectrofocusing of 125I-ABP demonstrated 3 isoproteins isoelectric at pH 4.7, 4.9 and 5.3 and the sedimentation coefficient was estimated to be 4.7 S in sucrose gradient ultracentrifugation. The 125I-ABP had similar physiochemical properties to the non-labelled ABP of epididymis.

Androgen-Binding Protein↗
PubMed1986

In-utero gentamicin-induced nephrotoxicity in rats.

Aminosides lead to a well-known nephrotoxicity. The possibility of the developing kidney being altered in utero after the pregnant mother's administration has been investigated. We gave gentamicin (75 mg/kg/day) to pregnant rats during periods of organogenesis (days 7-11) and the beginning of glomeruli differentiation (days 14-18). A group of nonpregnant females was also treated for the same period and at the same time each day. Gentamicin-treated mothers presented only minor modifications of the blood biology with no acute renal failure when treated nonpregnant females have a hypercreatininemia. The deep cortical area, containing the fully formed nephrons of neonates, presented less glomeruli that were differentiated in the gentamicin group than in the control group. Moreover with both light and electron microscopy, glomeruli and proximal tubules showed evidences of nephrotoxicity in the juxtamedullary cortex. This finding of an in utero aminoside nephrotoxicity demonstrates the possible toxicity of gentamicin on fetus kidneys when given during the pregnancy.

Abnormalities, Drug-Induced↗
PubMed1985

Does the in-utero exposure to furosemide delay the renal maturation?

Two groups of pregnant Wistar rats were constituted, one treated with Furosemide IP and one with saline. The drug was given on days 7-11 and 14-18 of the pregnancy. Litters from the two groups were not different in number of pups, body weight, and/or kidney weight, but exposed in-utero neonates, studied shortly after birth, exhibited a significant lower number of differentiated glomeruli than those of the control group. As well as the difficulty of explaining this phenomenon, this condition raises the problem of a possible compensation by the postnatal nephrogenesis, which is important in the rat, and leads to the question of what will be the total amount of nephrons for the adult life in species with or without complete in utero nephrogenesis.

Animals↗
PubMed1981

[The human basophils degranulation test (HBDT). Leucoconcentration and statistical calculation applied to the degranulation rate (author's transl)].

The technique using hemolysis and vital coloration described by Benveniste permits the human basophils to be studied in immediate type allergies : HBDT. In almost 25% of the cases, the test cannot be carried out because the basophils are less than 20 per mm(3). In 700 but one case, the HBDT could be carried out using a leucoconcentration technique by means of a 100 to 200 g centrifugation of 10 mn duration, followed by tangential extraction, thus obtaining an increased number of basophils. The authors were lent to apply a statistical calculation to a significant degranulation rate due to the number of observable cells by means of an unilateral statistical test suggesting a distribution according to Poisson's law. Thus tests are interpreted more rapidly and are more reliable. On the other hand, comparison with the results obtained with or without leucoconcentration in different types of allergies due to reagins (drugs, hymenoptera, foods) do not show any cellular fragilization. It may be concluded to the reliability of the degranulation observed in presence of an antigen.

Basophils↗
PubMed1977

[Conditions affecting the application of the method of determining blood volume by the injection of labeled (iodine 131) serum albumin to small animals (chick embryo)].

The isotopic dilution method is really suitable for the determination of blood volume in small animals. The main purpose of this study is to find the limits of measuring errors made during the injection procedures (injected volumes about one microliter) and the sampling of blood (blood samples less than one milliliter). After evaluation of the extravascular rate of diffusion of the radioactive iodinated human serum-albumin, the blood volume of the 17 days incubated chick embryo is measured by this method for control purposes.

Animals↗
PubMedDate not supplied

Effect of in utero infusion route on lymphocyte distribution in fetal rat tissues.

Infusion of cells into the fetus is a new form of intrauterine therapy for several genetic disorders. The effect of in utero infusion routes on labelled lymphocyte distribution in fetal rat organs was investigated. Fetuses, 14-16 days of gestation, were infused in utero with a Hoechst 33342 (bis-benzamide) labelled lymphocyte and FITC-labelled polystyrene bead mixture via four routes: intraperitoneal, intraplacental, intra-amniotic, and intravenous. The distribution within tissues was evaluated in frozen sections of placenta and fetal organs. Our results suggest that among the four routes tested, the intravenous route offered the possibility to reach easily fetal organs without any cell loss and yielded higher cell and bead concentrations in fetal organs, especially in the liver and in the kidney. In conclusion, the intravenous route seems to be appropriate for hematopoietic cell transplantation in the developing fetus.

Animals↗