PubMed Health⌕ Search

Biomedical subjects

M C Clavequin

Publications and source records attributed to M C Clavequin.

27 records · Page 2Linked to original sources
PubMed1984

Ontogeny of the neuroglandular system revealed with HPGRF 44 antibodies in human hypothalamus.

Using the indirect immunofluorescence technique, an antiserum to synthetic hpGRF 44 (the 44 residue peptide with high growth hormone releasing activity isolated from a human pancreatic tumor), antibodies of which interact with 40-44 C terminal amino acid sequence, stains a novel neuron system in the adult human hypothalamus. HpGRF-like immunoreactivity (GLI) containing neurons are different from previously known peptidergic systems. GLI perikarya are few in number and located mainly in the infundibular nucleus. In the median eminence, abundant GLI fibers terminate against portal capillaries in the same areas as somatostatin fibers which are morphologically different. No GLI staining was observed in hypothalami before 18 weeks of fetal development. GLI perikarya and intraeminential nerve terminals were simultaneously detected in 18-week-old fetuses attesting to a possible release of this peptide in the portal vessels as early as this stage. GLI neuron system was steadily revealed in 19- to 30-week-old fetuses. It was not detectable in 6 out of the 7 studied hypothalami from newborn infants. In most infant and adult hypothalami, it is well developed. Results presented here support the hypothesis (1) that hpGRF antiserum stains the neuron system producing the somatocrinin and (2) that this neuron system may begin in controlling pituitary somatotrophs at the 18th week of fetal development, which is in agreement with previous hypotheses.

Adult↗
PubMed1983

Immunocytochemical demonstration of a novel peptidergic neurone system in the cat brain with an anti-growth hormone-releasing factor serum.

In 15-day-, 1-month- and 1.5-month- old cats an antiserum against hpGRF-44 stained a novel hypothalamo-infundibular neuroglandular system. Its intra-eminential processes present an important development between 15 and 30 days of age. Perikarya and nerve fibres, which are abundant in several brain areas as early as the 15th day, suggest that the peptide revealed by hpGRF-44 antibodies also acts as a neuromodulator.

Animals↗
PubMed1983

[Comparative immunocytochemical study of the neuroglandular hypothalamic CRF system in the postnatal period in dogs and cats].

Immunocytochemical visualization, and comparative morphological analysis of the paraventriculo-infundibular CRF-positive system was performed in new-born dogs and young cats. Our studies underline the identity of this system and its structural similarity among Mammals. They confirm the interspecificity of the antigenic sites recognized by our ovine CRF-antibodies.

Aging↗
PubMed1983

[Human ontogeny of the hypothalamic neuroglandular system immunoreactive to an anti-hpGRF 44 immune serum].

An hypothalamo-infundibular neuroglandular system stained by an anti-hpGRF 44 serum is described in human brain. Perikarya are located in the infundibular nucleus, and their fibres end in posterior and lateral territories of the zona externa of the Median Eminence . Somatostatin fibres, morphologically different, also end in the same areas. Fibres giving intra- eminential terminals, so as hypothalamic perikarya are revealed as early as the 18 th week of fetal life.

Adult↗
PubMed1982

[Immunocytochemical study of the ontogenesis of the CRF-containing neuroglandular system in the human hypothalamus (author's transl)].

In the human fetus, the first anti CRF-stained fibres appear in the median eminence during the 16th week. From the 17th week, they are more numerous and they establish neurohemal terminals close to the superficial capillaries and around some of the developing intra-eminential vascular loops. In new born infants infundibular CRF-containing processes and terminals are strongly immunoreactive and very few CRF-containing perikarya can be detected in the paraventricular nucleus.

Corticotropin-Releasing Hormone↗
PubMed1982

Quantitative immunocytochemical studies on the gonadotrophs isolated from the pituitary of the male rat.

Quantitative studies on the population of the gonadotropic cells in the pituitary of adult male rats were performed after trypsic dissociation of the pituitary glands and immunoenzymatic staining with anti-beta-LH or anti-beta-FSH antisera. Number, area and extinction of labelled cells were measured by use of an image analyser and a cytophotometer. The gonadotrophs represent approximately 14% of the pituitary cells. The mean area of gonadotrophs is significantly larger after staining with anti-beta-LH serum than after staining with anti-beta-FSH serum. Planimetric measurement of the gonadotrophs reveals their variability in size ranging between 30 and 160 microns2. Moreover, the size distribution depends on the staining serum used: more numerous small-sized cells (less than 75 microns2) are stained with anti-beta-FSH serum than with anti-beta-LH serum, which conversely stains more numerous large-sized cells. Cytophotometric measurements indicate that immunostaining varies greatly among cells of the same size class and that the staining intensity appears to increase according to the cell size. These results emphasize the morphofunctional heterogeneity of the gonadotropic cell population.

Animals↗
PubMed1980

[In vitro effects of glycolytic substrates and some nucleotides (ATP, ADP, AMP, cyclic AMP) on the motility of spermatozoids of human sperm, asthenospermic or normal].

The effects of several drugs upon normal and asthenospermic human sperms were tested: cyclic AMP significantly and constantly increased the rate of motile spermatozoa in most samples having an initial motility rate between 20 and 60%. ATP kept up high the motility rate, particularly in sperm displaying the highest initial motility. Other drugs (glycolytic substrates, pyruvate, ADP, AMP, caffeine had inconstant effects upon a few sperms. None drug was efficient upon sperms with initial motility rate lower than 20%; this was probably due to important lesions of the locomotor apparatus of the spermatozoa, as shown by electron microscopy investigations.

Adenine Nucleotides↗