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Biomedical subjects

Y Menezo

Publications and source records attributed to Y Menezo.

65 records · Page 4Linked to original sources
PubMed1979

Enzyme comparative study of spermatozoa and seminal plasma in normal and subfertile man.

A semiquantitative colorimetric micromethod (APIZYM) was used to study the enzyme profiles of seminal plasma and of spermatozoa. Reactions with 65 different substrates are simultaneously tested in a single specimen. These substrates (principally naphtolic) allow the detection of hydrolytic enzymes (esterases, phosphatases, and peptidases) and of dehydrogenases potentially involved in sperm metabolism and in the process of fertilization. The usual sperm enzymes were regularly observed: C3-C4 esterases, amino acid arylamidases, acrosine, phosphatases, glutamyl transpeptidase, and various osidases. Among the dehydrogenases we observed a striking predominance of the enzymes of the hexose monophosphate shunt and of LDH. Seminal plasma has an enzyme pattern very similar to that of spermatozoa except for the absence of acrosine and of some dehydrogenases. This unexpected similarity is discussed. The gametes from subfertile donors do not at first sight differ in their enzyme pattern from those from fertile donors. Moreover, we found no marked differences between zymograms of seminal plasma from normal, subfertile, or even azoospermic patients. Deep freezing does not modify the hydrolytic enzymes of human sperm either quantitatively of qualitatively, but the dehydrogenases of the hexose monophosphate shunt are adversely affected (60% loss of activity for G 6 PDH, and 30% for 6 PGDH); LDH is not affected. The consequences on fertilizing capacity of frozen semen are discussed.

Humans↗
PubMed1978

A rapid quantitative analysis of tyrosine and its oxidation products by tyrosinase.

A new technique based on liquid phase ion exchange chromatography on short column is proposed for quantitative determination of tyrosine and Dopa. alpha-Amino,beta-guanidinopropionic acid is used as an internal standard of coloration. The role of H2O2 and ascorbic acid on tyrosine and Dopa was checked. Ascorbic acid prevents the auto-oxidation of Dopa, H2O2 has no effect on tyrosine but oxidizes Dopa even in the presence of excess ascorbic acid. This method was tested in mushroom tyrosinase, with and without ascorbic acid. Assays performed with tyrosinase from rabbit ocular extracts clearly showed that they do oxidize tyrosine. Reliability of the method is comparable to radioassay.

Alanine↗
PubMed1976

[Synthetic medium for gamete survival and maturation and for culture of fertilized eggs].

A defined medium more similar to female genital tract fluids than to blood serum is tested on bull sperm survival, calf oocyte maturation and cleavage of Rabbit and Cow fertilized eggs: -- after incubation for 24 hrs. at 38 degrees C, 20 to 40 p. 100 of the spermatozoa remain motile in two-thirds of the samples; -- 95 p. 100 of immature calf oocytes reach metaphase II after 24 hrs. of culture in the presence of gonadotropins; -- 57 p. 100 of Rabbit morulae divide during 50 hrs. culture as compared to 40 p. 100 in HAM F/10 medium; -- 65 p. 100 of the Cow blastocysts hatch in vitro as compared to 18 p. 100 with Brinster medium.

Amino Acids↗
PubMed1975

Preovulatory and ovulatory mechanisms in oocyte maturation.

Studies of the effect of gonadotrophins on the cumulus and oocyte or on the whole follicle in vitro offer a good tool for understanding the mechanisms of oocyte maturation, the ability of follicles of different sizes to respond to gonadotrophins and the processes of atresia. The birth of normal young from intrafollicular oocytes matured in vitro furnishes proof that in-vitro techniques are valuable as long as follicular integrity is maintained during the whole culture period.

Animals↗
PubMedDate not supplied

Isolation and long-term maintenance of differentiated adult chicken hepatocytes in primary culture.

Adult chicken hepatocytes were obtained by an adaptation of the two step in situ collagenase perfusion. Usually 0.5 to 1 x 10(9) cells were obtained, with 75 to 95% viability. Hepatocytes attached within 2 h when plated on plastic cell culture dishes and spread in 4 h, surviving for several months in a specific serum-free medium. These cells retained a typical parenchymal cell morphology and the ability to produce a specific protein (albumin) throughout the culture period. We hereby provide a suitable model for studying hepatic metabolism in birds.

Albumins↗
PubMedDate not supplied

Conception and realization of artificial dyed embryos for training in in vitro fertilization and embryo transfer (IVF and ET).

An artificial embryo model is proposed for current training in in vitro fertilization and embryo transfer. It consists in resin microballs of 180 micron diameter, stained either with fluoresceinamin or methylene blue. These microspheres release, even at the maximum dye concentrations tested, very negligible amounts of dye; heat stable they can be sterilized. This model, already checked for human embryo transfer, seems to be a useful tool in other reproduction studies such as embryo transport.

Education, Medical, Continuing↗
PubMedDate not supplied

Catecholamine levels in relation to number of spermatozoa inseminated "in vitro" in the human being.

We tried to understand and to explain why such a high number of sperm cells is necessary for human in vitro fertilization in relation to the possible role of catecholamines. Sperm cells, even washed several times, bring catecholamines (epinephrine, nor-epinephrine and dopamine). When incubated in a suitable medium, with Taurine and reducing agents, the catecholamine level remains constant for 5 hours. The origin of these amines and the positive vs negative effect of "in vitro" insemination with a high number of spermatozoa are discussed.

Catecholamines↗