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Biomedical subjects

F Vidal

Publications and source records attributed to F Vidal.

At least 271 records · Page 15Linked to original sources
PubMed1982

Meiotic and synaptonemal complex studies in 45 subfertile males.

We describe the results of meiotic and synaptonemal complex (SC) studies in a selected series of 45 subfertile males with different meiotic and seminal alterations. SC anomalies (pairing anomalies, fragmented SCs, or presynaptic arrest) were observed in 32 cases (71.1%). In 31% of the abnormal cases, meiotic anomalies could only be detected through the study of SCs. The origin of synaptic anomalies may be related to the assembly of myosin molecules along the chromosomes. SC analysis should become routine in the study of subfertile males.

Biopsy↗
PubMed1982

Meiotic and synaptonemal complex studies in a 14/21 translocation carrier.

Meiotic studies in a sterile carrier of a 14/21 translocation showed a meiotic arrest, with degeneration of primary spermatocytes. Silver staining of pachytene cells revealed the presence of a trivalent. Its synaptonemal complex was quite similar to that described in previous light and electron microscopy studied in mammalian species. The observation of a trivalent with pairing in trans-configuration and the presence of desynaptic synaptonemal complexes in early pachytene could explain the relatively high incidence of non-disjunction in human D/G translocations and the spermatogenic disintegration sometimes seen in these cases.

Adult↗
PubMedDate not supplied

Influence of pH, malic acid and glucose concentrations on malic acid consumption by Saccharomyces cerevisiae.

Malic acid consumption by Saccharomyces cerevisiae was studied in a synthetic medium. The extent of malic acid degradation is affected by its initial concentration, the extent and the rate of deacidification increased with initial malate concentration up to 10 milligrams. For malic acid consumption, an optimal pH range of 3-3.5 was found, confirming that non-dissociated organic acids enter S. cerevisiae cells by simple diffusion. A full factorial design has been employed to describe a statistical model of the effect of sugar and malic acid on the quantity of malate degraded (milligrams) by a given amount of biomass (milligrams). The results indicated that the initial malic acid concentration is very important for the ratio of malate consumption to quantity of biomass. The yeast was found to be most efficient at higher levels of malate.

Biomass↗
PubMedDate not supplied

Preimplantation genetic screening and human implantation.

In recent years, preimplantation genetic screening (PGS) has been used and recommended to increase the implantation rate in older women or in couples with previous assisted reproduction (ART) failures, to try to increase pregnancy rates in couples with recurrent abortions, to prevent the transmission of chromosome anomalies to the offspring of carriers of balanced chromosomal rearrangements, or even to try to decrease the incidence of trisomic births in older women. So far, PGS has contributed to increase the implantation rate in older women; however, the rate of clinical pregnancies has not increased, either in older women or in couples with previous ART failures. In couples with recurrent abortions, the pregnancy rate seems to increase, but only when the woman is young (< or =35). In carriers of balanced reorganizations, the prognosis is poor. Attempts to decrease the birth of trisomic children to older women are difficult to evaluate. This absence of relevant results is not related to the technique itself, which is quite safe, but to other still largely unknown factors.

Abortion, Habitual↗