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Biomedical subjects

Y Menezo

Publications and source records attributed to Y Menezo.

At least 55 records · Page 3Linked to original sources
PubMed1986

A tetrapeptide isolated from hamster embryo with central opiate properties on gastrointestinal motility but not on pain perception.

The effects of centrally administered kentsin (H-Thr-Pro-Arg-Lys-OH) on intestinal motility and on pain perception were investigated in rats chronically equipped with lateral ventricle catheters. Intestinal motility was recorded electromyographically from electrodes placed on the duodeno-jejunum; analgesia was evaluated by the hot-plate and tail-flick tests. Kentsin (4.0 ug/kg), injected intracerebroventricularly (ICV) 2 hours after the beginning of a meal, restores the "fasted" i.e. the migrating myoelectric complex of intestinal motility, while a 5 times higher dose administered subcutaneously was inactive. The ICV effect of kentsin was blocked by previous ICV administration of naloxone (400 ug/kg). In contrast, kentsin administered ICV (40 ug/kg) or SC (200 ug/kg) did not affect significantly (P greater than 0.05) the time latency in the two analgesic tests during 90 minutes after its administration and did not significantly modify the analgesic effects of (D5-Ala2, Met5) enkephalinamide. We conclude that kentsin when centrally administered acts on opiate receptors to alter gastrointestinal motility but without effects on pain perception.

Animals↗
PubMed1986

The use of synthetic culture medium and patient serum for human in vitro fertilization and embryo replacement.

The use of heat-inactivated patient serum as both fertilization and embryo replacement medium was compared in a prospective randomized study with a fully synthetic culture medium containing human serum albumin without serum addition (B3 INRA Menezo). Another series of the author's IVF program was analyzed retrospectively when a commercially available synthetic medium with bovine serum albumin (B2 INRA Menezo) or B3, as mentioned above, was used without serum addition for fertilization but with 50-100% patient serum as embryo replacement medium. Fertilization rates were significantly higher in the synthetic culture media (70%) than in serum (57%). The rate of polyploid fertilization was significantly lowest in B3 medium. There was a clear trend toward better pregnancy rates when high-percentage or 100% patient serum was used for embryo replacement, no matter if one, two, three, four or more embryos were replaced. We conclude that there should be no need for any kind of serum addition to fertilization media. The present study proves our previous observation that the use of serum seems to be beneficial as embryo replacement medium. This might well be explained by a "protein stick effect" due to the high macromolecular contents of serum rather than by viscosity measurements, since no significant increase in viscosity was observed when a high percentage of serum was added to culture media.

Blood↗
PubMed1985

Central opioid-like influence of a tetrapeptide from hamster embryo (kentsin) on gastrointestinal motility in dogs.

The effects of intracerebroventricular (i.c.v.) vs. intravenous (i.v.) administration of kentsin (H-Thr-Pro-Arg-Lys-OH) on gastrointestinal motility were investigated in fasted dogs. Administered i.c.v. at doses of 20 and 100 ng/kg, this peptide inhibited by 51.2 and 76.1% the antral motility index and disrupted the jejunal migrating motor complex for 2 and 4 h respectively. Similar effects were only obtained after a 25 fold higher dose administered i.v. and these effects were abolished after a previous i.c.v. administration of naloxone (50 micrograms/kg) suggesting that they are mediated through opiate receptors.

Animals↗
PubMed1985

Influence of skin illumination on serum acetylcholinesterase of the rabbit.

The effects of skin illumination (continuous or discontinuous colorless or yellow filtered white light) on acetylcholinesterase levels are tested on rabbit serum. Significant increases in acetylcholinesterase are observed with continuous and discontinuous colorless filtered white light as compared to controls.

Acetylcholinesterase↗
PubMed1984

Purification and characterization of ubiquitin from mammalian testis.

Ubiquitin was extracted from testis of 4 mammals and purified to homogeneity by gel filtration chromatography. Amino acid compositions and NH2-terminal sequences were found to be identical in the 4 species and with calf thymus ubiquitin. Ubiquitin conformation was shown to be very sensitive to oxidation. Improved methods for radioimmunoassay of ubiquitin in tissue extracts are also discussed.

Amino Acid Sequence↗
PubMed1984

Serum is not necessary in human in vitro fertilization, early embryo culture, and transfer.

Human in vitro fertilization (IVF), embryo culture (EC), and embryo transfer (ET) are commonly performed in various media supplemented with blood serum. To determine whether serum is really necessary, the results of IVF, EC, and ET were compared by using two types of media: B2 medium supplemented with human cord serum and B3 medium without any serum. B3 medium is similar to B2, except that it contains 1% pure controlled human serum albumin in place of 1% bovine serum albumin. We did not observe any difference between the results obtained by using B2 or B3 at any phase of IVF, EC, and ET processes. Both media give an overall evolutive pregnancy rate of about 16%. B3 medium with serum seems to increase slightly the cleavage speed. Our results indicate that there are no positive effects when serum is used for human IVF-ET. To avoid serum supplementation is of evident interest for the homogeneity of the results. This will also lead to a better understanding of human early development and control of the egg quality by metabolic analysis of the media following in vitro EC.

Animals↗
PubMed1984

Human preovulatory follicular fluid: the lipids. Are they the trigger for capacitation?

The lipid content of human follicles within 6 h of ovulation was determined. Levels for triglycerides, phospholipids, and total cholesterol were 1/4 to 1/3 of those in serum. An uncommonly high level of free cholesterol was observed, possibly resulting from a high synthetic rate by the granulosa. Follicular lipids appear to be of serum origin since the relative proportions of the various fatty acids are the same. Arachidonic acid was not found to be present at the high levels reported for "large" porcine follicles, possibly due to its active utilization in the synthesis of prostaglandins necessary for the ovulation process. Precise timing relative to ovulation is clearly essential for follicular classification in order to distinguish between before and after the triggering of the ovulation process. A possible role for lipids in the induction of capacitation is proposed.

Adult↗
PubMed1983

[Free and peptide amino acid composition in the seminal fluid of the carp (Cyprinus carpio)].

Free and peptidic amino acids were measured in the seminal plasma of carp. Some acids such as glutamic acid and glutamine, taurine, glycine and proline were exceptionally abundant, while others like lysine, arginine and histidine were found in small amounts. Generally, the amino acid level was higher in carp seminal plasma than in that of other Vertebrate species. As this level was systematically higher than in the blood plasma, it is supposed that there was neoformation of an original fluid in the genital tract.

Amino Acids↗
PubMed1983

Influence of cations and albumin on human spermatozoa.

The effects of potassium, calcium and magnesium cations, and albumin on motility of spermatozoa, were tested after 15 min, 4 hr, and 24 hr of incubation using laser Doppler velocimetry. The optimal concentration of K+ was found to be 11 mM; higher values decreased motility more severely than did lower ones, even when K+ was completely removed. Motility was increased in the presence of small amounts of calcium (from 0.8-1.7 mM) but was depressed by magnesium concentrations above 0.8 mM. Moderate concentrations of albumin (0.5-1%) improved motility, but the protecting effect of this compound--leading to a best sperm survival--appeared with higher concentrations (4%). In conclusion we observed that optimal ionic conditions presently found were corresponding well to the tubal environment in preovulatory phase.

Albumins↗
PubMed1982

Kinetic study of fatty acid composition of day 7 to day 14 cow embryos.

Day 7 to Day 14 cow embryos were analyzed by gas chromatography and mass spectrometry for their fatty acid content. The total amount per embryo does not change between Day 7 and Day 10, but then increases sharply between Days 11 and 13, suggesting that it is related to blastocyst volume or weight. With increasing embryonic age, there is an increase in the fatty acid elongation and desaturation. Arachidonic acid is present in significant amounts on Day 14 which may indicate that prostaglandin synthesis has started. The composition of the fatty acids bound to bovine serum albumin (BSA) is similar to that for embryos. Therefore, this macromolecule may be of special value for adding lipids in culture media for mammalian embryos.

Animals↗
PubMed1982

Influence of skin illumination on plasma biogenic amines in the rabbit.

The effects of skin illumination on plasma catecholamines were tested in the rabbit. The values observed for epinephrine, nor-epinephrine and dopamine, dosed by the radioenzymatic technique, were in accordance with those generally published. However, variability is important. Discontinuous skin illumination significantly increased (P less than or equal to 0.05) only the level of dopamine in plasma. No evident demonstration can explain this elevation, but the role of the important interrelations between L-dopa, involved in melanogenic activity, and dopamine is discussed as the first step in the understanding of such a phenomenon.

Animals↗
PubMed1982

The preovulatory follicular fluid in the human: influence of hormonal pretreatment (clomiphene-hCG) on some biochemical and biophysical variables.

Some biochemical and biophysical variables of human follicular fluid have been studied both in normal women after the LH peak (preovulatory follicles) and in women treated with clomiphene and hCG (clomiphene treated follicles). The results showed that lactate and glucose levels are different from those found in serum but are not influenced by the clomiphene treatments. Osmolarity and enzymatic contents are neither different from those of serum nor modified by the hormonal treatments. The transfer of water across the follicle wall was found to be closely regulated because only slight variations were observed in the wide range of volumes collected in the samples examined.

Adult↗
PubMed1981

Enzymes in the seminal plasma from azoospermic men: correlation with the origin of their azoospermia.

Semi-quantitative estimations of the activities of 65 enzymes were studied for cases of azoospermia in an attempt to correlate the seminal enzyme profile with the origin of the azoospermia. One single enzyme--alpha-glucosidase--showed variation. All other specificities tested gave identical results for all the azoospermic samples and for normal controls. The alpha-glucosidase activity that is present in normal semen was absent from samples from patients with azoospermia associated with a complete obstruction of the genital tract, and also from all semen samples from vasectomized subjects. This enzyme appears to be secreted by the epididymis, and the activity present in azoospermic semen can provide information concerning the origin of the azoospermia and the functional state of the epididymis. Positive but reduced alpha-glucosidase activity appears to be frequently associated with inflammatory disease. The consequences of these findings are discussed.

Follicle Stimulating Hormone↗
PubMed1981

["In vitro" culture of the oviduct of women, rats and rabbits. Preliminary results (author's transl)].

A continuous flow perfusion system which has been improved for the culture of large pieces of tissue, e.g. epididymis and ovarian follicles was tested for the entire oviduct in women, rabbits and rats. The histological properties of the organ were maintained after a day or two of culture; but only in the presence of oestrogens. Progesterone seems to induce a weakness of epithelial cell attachment and these become scattered in the lumen. In women the cultures seemed to be more or less permanently contamined, probably due to commensals, because this problem did not occur with rat or rabbit oviducts.

Animals↗
PubMed1980

In-vitro uptake of glucose by bovine blastocysts.

Blastocysts, obtained from cows on Day 10-11 after oestrus, were cultured for 20 h. Most (81.3%) blastocysts grew in culture and about 50% took up glucose. There was no morphological difference between the blastocysts which did or did not take up glucose but development in vivo was better for blastocysts which had taken up glucose (69.2%) than for those which did not (14.2%).

Animals↗
PubMed1980

[Energy metabolism of spermatozoa: present status of the subject].

The energetic metabolism of the human sperm is characterized by the predominant importance of glycolytic pathway, with the probable participation of the pentose shunt. The participation of the aerobic pathway is very small since the oxidative phosphorylation seems to be partially uncoupled at time of ejaculation. There is no correlation between the respiratory activity and the mobility of the sperm. The effects of several physicochemical conditions were studied, indicating that the spermatozoon is indeed very resistant to variations of its environment. Seminal plasma seems to be a rather unsuitable medium for investigations of the glycolytic pathway, with the probable participation of the pentose shunt.

Adenosine Triphosphate↗
PubMed1979

Cholinesterases isoenzymes: a comparative study in the skin and plasma.

Acetylcholinesterase (Ache) and pseudocholinesterase (BUche) activities were studied quantitatively in healthy skin by spectrophotometric methods and qualitatively by polyacrylamide gel electrophoresis. The results were compared to those obtained in plasma. The substrates used to reveal enzyme activities were acetylthiocholine (ATC) iodide and butyrylthiocholine (BTC) iodide, respectively. A linear relationship exists between the values of BUche and Ache activities in plasma and those in skin. Six isoenzymes of different electrophoretic mobility were observed in the skin. One of them, which is never found in plasma extracts, appears to be specific to the skin. On gradient gel electrophoresis, with both substrates (ATC and BTC), a single band of enzyme activity, corresponding to a molecular weight of 600,000 was observed. These results suggest that in the skin there is only one enzyme, most probably butyryl cholinesterase, which cleaves BTC somewhat faster than ATC. This methodology, when applied to the study of dermatoses in which abnormalities of cutaneous nerve terminals are suspected, should furnish precise functional pathophysiological details.

Acetylcholinesterase↗