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M Volante

Publications and source records attributed to M Volante.

48 records · Page 3Linked to original sources
PubMed1995

Cytogenetic analysis of uncleaved oocytes after intracytoplasmic sperm injection.

PURPOSE: This work analyzes the causes of cleavage failure after intracytoplasmic sperm injection (ICSI) and the effect of the procedure on the chromosomes of the oocytes. METHODS: Ninety-seven uncleaved oocytes from 39 patients with severe male infertility or repeated IVF failure were fixed; 79 were analyzable. We checked the decondensation stage of spermatozoa nucleus and the chromosomal abnormalities of the oocytes. RESULTS: Among the fixed oocytes, the spermatozoa nucleus was present in 97% of the cases, and it was undecondensed in 89% of the cases, showing no evolution at all. A low rate (2.6%) of premature chromosome condensation (PCC) of the spermatozoa and a low rate (2.5%) of female diploïdy were observed. Among the oocytes that could be karyotyped, we observed a high rate (45%) of chromosome breakage. CONCLUSION: ICSI fertilization failure was due mostly to the complete lack of evolution of the spermatozoa nucleus. Oocyte selection before ICSI seemed to lower the PCC rate. The high rate of oocyte chromosomal breakage rate has to be confirmed.

Chromosome Aberrations↗
PubMed1995

Physicochemical properties of crystalline silica dusts and their possible implication in various biological responses.

The effect of grinding, heating, and etching was investigated on polymorphs of silicon dioxide exhibiting different biological responses. Diatomaceous earths were converted into cristobalite at 1000 degrees C. Dusts obtained by grinding crystalline minerals exhibited different micromorphology and a propensity to originate surface radicals which decrease in the sequence cristobalite --> quartz --> coesite --> stishovite. The production of surface radicals was suppressed by grinding in the presence of water. Thermal treatments selectively quenched the radicals and decreased surface hydrophilicity. Quartz treated with aluminum lactate exhibited higher surface acidity when compared with pure quartz, with a reduction in fibrogenicity. Etching by hydrofluoric acid smoothed the particles with loss of specific surface. Adsorption of water on three cristobalite dusts of different origin (ground mineral, ex-diatomite, heated quartz) indicated a loss in heated quartz (1300 degrees C) that was relatable to the corresponding reduction in fibrogenicity.

Chemical Phenomena↗
PubMed1994

[Value of cryopreservation of human embryos during the blastocyst stage].

The recent development of co-culture technique has permitted to cryopreserve human embryos at the blastocyst stage. The aim of the present study was to compare pregnancy rates after transfers of embryos frozen at an early embryo stage (2-8 cell stage, group A; n = 175) with others frozen at blastocyst stage (group B; n = 98). Our results demonstrated that the frozen/thawed blastocyst survival is approximately 100%. In comparison the early embryos survival rate was 59% (P < 0.05). Moreover, pregnancy rates/embryo transfer in group A (16.4%) were significantly improved by comparison to those observed with early embryos (6.2%) (P < 0.05). In conclusion, our results demonstrate that embryo frozen/thawed at the blastocyst stage can be useful for improving pregnancy rates after cryopreservation.

Blastocyst↗
PubMed1990

Chemical functionalities at the silica surface determining its reactivity when inhaled. Formation and reactivity of surface radicals.

Reactive radicals at the surface of quartz or other SiO2 polymorphs have been studied by EPR in relation to their possible role in pathogenicity. All the examined dusts bear the characteristic radicals of silica ground in air: Si, SiO., SiO.2 (peroxyradical) and O2.- (superoxide ion), but some also show additional spectral lines belonging to other radical forms. Comparison of standard quartz dusts (DQ-12, Min-u-sil 5) with a natural quartz and with what obtained by grinding a very pure quartz crystal indicates that to a higher purity corresponds a higher radical population. Cristobalite and vitreous silica exhibit similar spectra, with larger proportion by respect to quartz, of partially reduced oxygen forms. The reactivity of the silica surface towards O2 and NaClO aqueous solutions are investigated by examining the modification in the EPR spectra induced by these treatments. A possible mechanism for fibrogenicity is proposed whereby, within the activated macrophage, a catalytic reaction occurs between surface functionalities and macrophage oxygen metabolites. This reaction would trigger the abnormal production of fibroblast stimulating factors, ending up with silicosis.

Administration, Inhalation↗
PubMed1989

Embryo quality and uterine receptivity in in-vitro fertilization cycles with or without agonists of gonadotrophin-releasing hormone.

The proportion of abnormal oocytes or embryos per recovered oocyte in in-vitro fertilization (IVF) cycles had no influence on the occurrence of pregnancy following the transfer of normal embryo(s) derived from oocytes capable of fertilization. There were more implantations per transferred embryo in stimulated IVF cycles using long-acting buserelin (30.0%) compared with short-acting decapeptyl (17.3%) or no gonadotrophin-releasing hormone agonist (GnRHa, 15.2%) treatments. However, the chances of implantation per embryo transferred being in excess of one in patients who became pregnant tended to be higher in non-GnRHa (23.5%) compared to buserelin- (16.4%) or decapeptyl- (13.3%) treated IVF cycles. Moreover, frozen--thawed embryos had a higher implantation rate (P less than 0.05) when originating from IVF cycles without GnRHa (11.7%) compared to GnRHa-treated cycles (buserelin, 4.3%; decapeptyl, 5.9%). It can be concluded that GnRHa associated with gonadotrophins produced embryos of a poorer aptitude for development than stimulation treatments without GnRHa. The clinical efficacy of GnRHa in IVF--ET cycles could be the result of an improved uterine receptivity to the transferred embryos.

Adult↗
PubMed1988

[In vivo and in vitro fertilizing ability of immature human epididymal spermatozoa].

In cases of congenital absence of vas deferens (9 patients) or after failure of previous epididymovasostomy (2 patients), in vitro fertilization (IVF) was attempted with spermatozoa surgically obtained at the epididymal caput level. These sperm populations showed little progressive motility (5.9 +/- 6.5%) and an marked necrozoospermia (19.3 +/- 17.4%). Stimulation by caffeine (4.5 mM) alone or associated with heterologue normal seminal fluid resulted in most of the cases in an initiation of motility with an improvement of the progressive velocity. In 9 IVF attempts, 31 mature oocytes were inseminated with 5.10(3) to 1.5.10(6) motile spermatozoa. The dynamic characteristics in 3 inseminated sperm populations were Vp (24.2 +/- 8.3 microns/s), Ah (8.6 +/- 2.0 microns) at room temperature. Sperm binding to zona pellucida was decreased (0 to about 20 spermatozoa per oocyte) and there was no fertilization. In the same period, 21 attempts of intra uterine insemination and 14 attempts of intracervical inseminations were made in 5 couples who remained infertile after patent high epididymovasostomy (4) or vasovasostomy (1) and having immature spermatozoa stimulated as previously described. Antisperm antibodies were detected on the ejaculated spermatozoa in four men. No pregnancy was obtained with these immature stimulated spermatozoa. The fertility of the female partners was confirmed in 3 women after insemination with donor sperm.

Adult↗
PubMed1987

Human embryo viability related to freezing and thawing procedures.

Freezing and thawing procedures did not affect the chances of successful transfer of human embryos. The postimplantation viability of frozen-thawed embryos was equivalent to that of fresh, immediately transferred embryos. Selection of the embryos that were more suitable for freezing did influence the pregnancy rate after transfer of the remaining fresh embryos. The therapeutic efficacy of in vitro fertilization and embryo transfer programs will be greatly increased if only one embryo is transferred in the in vitro fertilization cycle, the others being separately frozen for further embryo transfer in subsequent cycles.

Embryo Transfer↗
PubMed1987

Importance of semen preparation in avoidance of reduced in vitro fertilization results attributable to bacteria.

Although the physical treatment of semen for IVF and related procedures is sufficient to remove most organisms present in semen, the pathogenic varieties tend to be more resistant. The supplementation of oocyte culture medium with both penicillin and streptomycin was associated with the eradication of 100% of organisms in the current study. In these circumstances, the presence of pathogenic organisms in the untreated semen is not associated with reduced oocyte fertilization in vitro.

Bacteria↗
PubMed1984

In vitro fertilization and embryo transfer program in Clamart, France.

Our in vitro fertilization and embryo transfer program really began in September 1980. Yet attempts to collect oocytes had been performed since 1978, and the first in vitro fertilizations were obtained in May 1979. The first pregnancy was obtained in April 1981, but it ended on the 12th week by a spontaneous abortion of a 45,X fetus. We have distinguished two periods in our program. The initial phase was from September 1980 until November 1982: ovulation monitoring of 365 cycles, spontaneous or stimulated, 276 laparoscopies, and 121 embryos transfers were performed, and 12 early pregnancies obtained (4.3% per laparoscopy and 9.9% per embryo transfer). Seven normal healthy infants were born (five boys and two girls); four cases were limited to biochemical pregnancies and one spontaneous abortion (yet described) was observed. The second and actual phase, December 1982-June 1983, is described more precisely: ovulation monitoring of 329 cycles, after stimulation protocols with clomiphene citrate and human menopausal gonadotropin, 230 laparoscopies, and 162 embryos transfers have been performed and have led to 34 pregnancies (14.8% per laparoscopy and 20.9% per embryo transfer). Eighteen of these 34 pregnancies are actually in progress (more than 12 weeks), 9 were limited to an increase in plasma human chorionic gonadotropin, and 7 cases ended in spontaneous abortions between 6 and 12 weeks.

Adult↗
PubMedDate not supplied

Tissue arrays as fiducial markers for section alignment in 3-D reconstruction technology.

Combination of conventional histology and the three-dimensional spatial view of tissue structures offers new prospects for understanding and diagnosing nature and development of human diseases. The essential technical problem related to three-dimensional reconstruction in histopathology is represented by the correct alignment of serial sections. During the past years several methods have been proposed but failed to become popular because of their limits in terms of time consume and restricted applicability. We aimed to overcome this problem by applying the technology of Tissue Array, thus by positioning adequate fiducial markers from specific "donor" blocks into the "recipient" paraffin block of interest. Digitized pictures of serially cut sections were aligned according to the tissue markers embedded by Tissue Array, and then processed with specific softwares for three-dimensional reconstruction. Thirteen models, including fetal hearts, breast and thyroid carcinomas, were elaborated. We found the procedure to be easy, fast and reproducible. Moreover, by selectively embedding the fiducial markers according to specific angles, the Tissue Arrays can be exploited in order to establish the distance between sections. This original methodology of incorporating Tissue Arrays into paraffin blocks as fiducial markers for three-dimensional reconstruction has a potential impact on histology for research purposes and diagnostic applications.

Algorithms↗
PubMedDate not supplied

[An etiological definition of a case of mixed pneumoconiosis due to silicates and coal in the absence of anamnestic data].

A case of pneumoconiosis with unknown occupational history was examined both pathologically and mineralogically by means of a variety of techniques, including analytical scanning and transmission electron microscopy with electron diffraction and energy dispersive x-ray analysis, and electron resonance spectroscopy. The pathologic features consisted of a diffuse interstitial fibrosis with deposits of amorphous and crystalline particles and granulomatous reaction. The identification of minerals, mainly talc, halloysite, coal and chlorite, allowed a definite diagnosis of mixed silicate pneumoconiosis to be made. This is an example of complete pathologic, mineralogic and physico-chemical analysis of a case of pneumoconiosis.

Aged↗