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G Grignon

Publications and source records attributed to G Grignon.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Expression of IL-2alpha and IL-2beta receptors on the membrane surface of human sperm.

Cytokines are secreted proteins that act as local immunological mediators. Increased seminal cytokine concentrations are associated with fertility problems. The purpose of the present study was to investigate the presence of IL-2alpha, and IL-2beta receptors on fresh and isolated sperm by flow cytometry and transmission electron microscopy. Twenty sperm samples from oligospermic men were incubated with CD25, a mouse monoclonal antibody specific for IL-2alpha-chain receptor, and CD122, a mouse monoclonal antibody specific for IL-2beta-chain receptor. The strong initial fluorescence intensity and, subsequently, a labeling index yielded by CD25 and CD122 decreased in sperm centrifuged on a Percoll gradient (p < .05). The expression of CD25 and CD122 correlated negatively with fresh sperm concentration, but in sperm centrifuged on a Percoll gradient there was no correlation. Labeling with CD25 and CD122 antibody was evident on the head and the middle piece in fresh sperm, while in sperm centrifuged on a Percoll gradient a weak labeling was observed only on the principal piece. The authors have identified and localized cytokine receptors on human sperm for the first time. Cytokine receptors may be involved in the regulation of pathophysiological events in sperm cell functions and male infertility. The exact pathway involved in modulation of these receptors requires further investigation. These results contribute to the understanding of cytokine-sperm relationships.

Flow Cytometry↗
PubMedDate not supplied

Gamma-glutamyl transpeptidase activity in the epididymis during fetal and postnatal development in rats.

The histochemical and biochemical distributions of gamma-glutamyl transpeptidase (gamma-GT) were investigated in the epididymis of rats during fetal and postnatal development. In the epididymal homogenates, gamma-GT activity was detected on the fifth day after birth. A sharp increase was observed after 30 days of life in the caput homogenates. Moderate levels of the enzyme were found in the cauda epididymis. Gamma-GT is histochemically detected from the 15th day of gestation in Wolffian ducts and in 17- to 18-day-old fetuses in newly differentiated epididymal tubules. Enzyme activity, was associated with the plasma membranes (apical, lateral, and basal), was preponderant on the apical part of the epithelial cells. During the first 15 days of the postnatal life, the histochemical reaction intensities were identical from the caput to the cauda epididymidis. From the 18th day onwards, enzyme activity decreased in the corpus and in the cauda, while gamma-GT increased in the caput epididymidis, and a strong activity was found on the apical surface of epithelial cells. Weak or moderate gamma-GT activity of spermatozoa in the caput tubules, increasing steadily from caput to cauda epididymidis, suggests that gamma-GT may be related to the functional maturation of spermatozoa.

Analysis of Variance↗
PubMedDate not supplied

Gamma-GT activity in the rat epididymis: effect of LHRH agonist (D-Trp 6-LHRH).

The aim of the present study was to follow the gamma-GT activity changes in the rat epididymis after withdrawal of androgens. Treatment of adult rats with the LHRH agonist D-Trp 6-LHRH led to reduce serum testosterone concentrations below the limit of detection of the assay. In the treated rats, specific activity of gamma-GT (nmol/min mg protein-1) drastically decreased in caput epididymidis. Histochemical reactions for gamma-GT completely disappeared in the initial and proximal segments but weak activity remained on the luminal plasma membranes of middle segment of the caput. In the corpus and cauda epididymidis, residual reaction for gamma-GT could be seen on the basal part of epithelial cells and on peritubular cells: Thus gamma-GT is confirmed to be androgen-dependent, but there is a regional responsiveness to withdrawal of androgen in the epididymis.

Animals↗
PubMedDate not supplied

Lectin-binding sites on human sperm during acrosome reaction: modifications judged by electron microscopy/flow cytometry.

Biochemical surface modifications occur during the capacitation and acrosome reaction of human sperm and among those, variations in the expression of carbohydrates moieties. A sequential study was performed with electronic microscopy and flow cytometry techniques, where the binding of 4 lectins was assessed on normal human sperm samples during in vitro induction of the acrosome reaction with calcium ionophore A-23187. Triticum vulgaris agglutinin (WGA) was shown to bind strongly the whole surface of sperm before induction of the acrosome reaction, and in lesser amounts after incubation with calcium ionophore. Arachis hypogea agglutinin (PNA) and mostly Concanavalia ensiformis agglutinin (Con-A) and Ulex europaeus agglutinin (UEA-1) binding evolved in an opposite pattern with an increase of the labeling parallel to that of GB24 antibody binding. Electron microscopy showed that the fluorescence patterns observed correlated with increased access to the inner membrane of the acrosome. This was significant 60 min after the induction of acrosome reaction. Lectin binding could be a useful tool to examine the ability of sperm samples to undergo the acrosome reaction.

Acrosome↗
PubMedDate not supplied

[The Ecole morphologique of Nancy: from Charles Morel to Paul Ancel at Pol Bouin].

The 1st October 1872, A. Thiers, french President de la Republique, gave order to transfer the Strasbourg Faculte de Medecine to Nancy. Then, Charles Morel was appointed professor for pathology and normal anatomy in Nancy where, in 1878, he got a professorship for histology. He introduced into this new Faculte the concept about cell theory and microscopic anatomy inherited from Strasbourg. He had a deep influence over A. Nicolas and A. Prenant who succeeded to him and founded the noteworthy morphological school of Nancy. Two of the most famous members of this school, P. Ancel and P. Bouin, left Nancy for Strasbourg, in 1919, when this city recovered its Faculte de Medecine. Their works about testis interstitial gland and ovary corpus luteum in Nancy were already famous. In Strasbourg, P. Bouin (histology) and P. Ancel (embryology) set up an original school of morphology. In short, Ch. Morel brought in Nancy the germs the fundamental concepts of modern morphology and a half a century later, P. Ancel and P. Bouin disciples of A. Nicolas and A. Prenant, carried back from Nancy to Strasbourg the offsprings of the impulses boosted by C. Morel.

Anatomy↗
PubMedDate not supplied

[Islet cell tumor with diarrhea and diabetes (glucagonoma?) associated with hyperparathyroidism. Long-term results of local-regional treatment with streptozotocin].

A case report of endocrine pancreatic tumour associated with diabetes and hyperparathyroidism is presented. Some arguments are in favour of a glucagonoma. Despite the absence of beta-cells in tumour, an exceptional result was obtained by use of Streptozotocin. This case brings up the relations between endocrine pancreatic tumours and parathyroid, and may be included in polyglandular adenoma syndrome.

Adenoma, Islet Cell↗