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Biomedical subjects

J Mandelbaum

Publications and source records attributed to J Mandelbaum.

At least 91 records · Page 5Linked to original sources
PubMed1986

Nucleologenesis in the human embryo developing in vitro: ultrastructural and autoradiographic analysis.

Nucleolar development during cleavage of human embryos in vitro was analyzed using combined autoradiographic and ultrastructural approaches. Human 2- to 4-cell embryos lack functionally active nucleoli. They possess nucleolus-like bodies formed by a homogeneous mass composed of densely packed fine fibrils. The nucleolus-like bodies contain no recently replicated embryonic DNA and do not show any detectable RNA synthesis. Their transformation into nucleoli is a relatively rapid process characterized by progressive infiltration of these bodies by adjacent chromatin, followed by the beginning of RNA synthesis and processing reflected by the appearance of the first nucleolar granules. These changes take place in 6- to 8-cell embryos, probably starting after the third cleavage division. Finally, most frequently in 10- to 12-cell embryos, typical nucleolar structure is established as a result of intranucleolar differentiation giving rise to distinct fibrillar and granular components as well as to nucleolar interstices. It is suggested that this pattern of nucleologenesis, different from that pertinent to mouse embryos (M. Geuskens and H. Alexandre (1984). Cell Differ. 14, 125-134), might be related to the relatively late activation of embryonic rRNA genes transcription and to the expressed rapidity of this process.

Blastomeres↗
PubMed1986

Steroid profiles during cycles with HCG stimulation of luteal function during in-vitro fertilization cycles.

178 in-vitro fertilization cycles have been explored for luteal function. Clomiphene and human menopausal gonadotrophins were used for ovarian stimulation and some patients were supplemented with human chorionic gonadotrophin (HCG) (5000 IU) on the day of laparoscopy, and also 2 and 4 days later. An imbalance of luteal function was observed in non-supplemented stimulated cycles, with hyperoestrogenicity and a relatively low production of progesterone. The administration of HCG reduced this imbalance by improving the production of progesterone without affecting the production of oestradiol-17 beta.

Adult↗
PubMed1986

Timing of in-vitro fertilization of cumulus-free and cumulus-enclosed human oocytes.

In humans, in contrast to other species, sperm capacitation requires a very short time, as in-vitro fertilization has been obtained after only 45 min of contact between oocytes and spermatozoa capacitated for 1 h. No fertilization occurred, whatever the duration of sperm capacitation, when gamete mixing did not exceed 30 min. On the contrary, 85% of cumulus-free mature oocytes exposed to sperm for 1-4 h were fertilized. The presence of the pre-ovulatory, fully-expanded or compact cumulus mass did not represent a physical barrier to sperm progression, as we observed no delay in fertilization when oocytes were enclosed in the cumulus. The use of a short insemination protocol (1-4 h instead of 17-20 h) did not reduce the fertilization rate of denuded or cumulus-enclosed oocytes and had no significant effect on the morphological appearance of the embryos or their cleavage rates.

Fertilization in Vitro↗
PubMed1986

Chromosome investigations in early life. I. Human oocytes recovered in an IVF programme.

Fifty-five oocytes recovered in an in-vitro fertilization (IVF) programme and remaining unfertilized when observed 42 h after insemination were prepared for chromosomal analysis. Sixteen oocytes displayed no polar body at the time of fixation and were supposed to be in metaphase I. In fact only two of them were in diakinesis, the others containing a diploid set of metaphase II chromosomes indicating that in 89% of the cases oocytes achieved meiosis without any extrusion of the first polar body. Thirty-nine oocytes in metaphase II were analysed. Nine were abnormal showing three D nullosomies, one G disomy, one double disomy for a 3 and a D chromosome, one deletion of the long arm of a G chromosome, one cell with extra chromosomes and/or chromosome breaks, one endoreduplication and one tetraploidy. The overall rate of abnormalities reached 22%. This high rate of chromosome anomalies can be explained by the nature of this population of fertilization failure, the frequently advanced maternal age and the use of superovulation treatments.

Chromosome Aberrations↗
PubMed1986

Activation of nucleolar and extranucleolar RNA synthesis and changes in the ribosomal content of human embryos developing in vitro.

RNA synthetic activity of human 2-16-cell embryos developing in vitro was studied by [3H]uridine light-microscope autoradiography. Parallelly cut thin sections were examined in the electron microscope. The first extranucleolar RNA synthesis was detected in 4-cell embryos, but nucleoli were never labelled until the 3rd cleavage (6-8-cell embryos). In 6-cell embryos the nucleolar labelling was mostly confined to a narrow peripheral zone. In later cleavage stages most of the blastomeres showed intensive labelling of nucleoli and extranucleolar chromatin. However, rather low levels of extranucleolar RNA synthesis and the absence of nucleolar activity were often seen even in blastomeres of fully compacted morulae. The activation of nucleolar RNA synthesis entailed a noticeable increase in the number of ribosomes (estimated by electron microscope morphometry) that followed a marked drop during the period between the 2-cell and 8-cell stages. The results indicate that the concentration of ribosomes in the preovulatory oocyte is a major factor of its developmental potential.

Autoradiography↗
PubMed1985

[Induction of ovulation by a luteinizing hormone releasing hormone pump. Principles, indications and results].

A new treatment of hypothalamic amenorrhea is based mainly on Knobil's data demonstrating the physiological pulsatile secretion of GnRH. This hormone can be administered intravenously in a chronic intermittent (pulsatile) fashion. Nine women suffering from hypothalamic amenorrhea received 1 pulse of GnRH 5 to 20 micrograms every 90 minutes via a portable infusion pump. Nine pregnancies were induced after a mean 1.5 cycle. Three precocious miscarriages occurred. At this moment two children are born and four other pregnancies are undelivered. Venous tolerance was excellent, except in one patient who developed repeated venitis. Pulsatile administration of GnRH is very effective in inducing ovulation without risk of hyperstimulation frequently observed with HMG-hCG.

Abortion, Spontaneous↗
PubMed1985

Sequential use of clomiphene citrate, human menopausal gonadotropin, and human chorionic gonadotropin in human in vitro fertilization. I. Follicular growth and oocyte suitability.

Sequential treatment with clomiphene citrate, human menopausal gonadotropin, and human chorionic gonadotropin was successfully applied to 149 women in the framework of an in vitro fertilization and embryo transfer program and led to the birth of normal children. An average of 3.5 follicles was promoted at each cycle. Oocyte maturity was evaluated at recovery either histologically or with respect to cumulus-oocyte complexes (COC) and correlated to oocyte fertilizability. Three types of COC are described according to cell dissociation and mucification. The most expanded cumulus mass (type I) was highly fertilizable, compared with granular and poorly dissociated cumulus complexes (types II and III, respectively). No improvement in the type II and III oocyte fertilizability was obtained when type I follicular fluid was added to the incubation medium. Moreover, incubation of type III oocytes in medium containing type III follicular fluid seemed to decrease their fertilizability.

Adult↗
PubMed1985

[Characteristics of pregnancies obtained by in vitro fertilization].

193 patients had 212 cycles induced for in vitro fertilisation between May 1983 and May 1984. 20 pregnancies of which 10 are still in progress were obtained with 6 spontaneous abortions. There were 2 so-called biochemical pregnancies and 3 extra-uterine pregnancies. The figure of 17% pregnancies where embryos were replaced totals less than 10% if one considers those pregnancies that really carry on. The number of extra-uterine pregnancies is disturbing. Finally, 2 multiple pregnancies continued, one of them being a quadruple pregnancy. The authors have made a special study to see the parameters of the conditions under which the pregnancies were obtained and the prognosis for such pregnancies.

Abortion, Spontaneous↗
PubMed1985

[Extrauterine pregnancy following in vitro fertilization, 2 of these associated with a developing intrauterine pregnancy].

Five cases of extra-uterine pregnancy occurred after in vitro fertilisation and embryo transfer. The case histories are given. All pregnancies occurred in the ampullary portions of the tubes. In two of the cases there was an on-going intra-uterine pregnancy as well as the ectopic. After the extra-uterine pregnancy had been operated on the intra-uterine pregnancies continued normally to term. In considering the tubal physiology the authors attempt to draw conclusions about the factors causing ectopic pregnancies after in vitro fertilisation.

Adult↗
PubMed1984

Sequential use of clomiphene citrate, human menopausal gonadotropin, and human chorionic gonadotropin in human in vitro fertilization. II. Study of luteal phase adequacy following aspiration of the preovulatory follicles.

The 88 patients included in the in vitro fertilization program during 113 cycles were submitted to superovulation by sequential use of clomiphene citrate, human menopausal gonadotropin, and human chorionic gonadotropin. No correlation was found between estradiol and progesterone levels during the luteal phase and estradiol on the days preceding administration of human chorionic gonadotropin. Nineteen biopsies of the endometrium were carried out. The importance of the increase of estradiol between the day before and the day of administration of human chorionic gonadotropin is positively correlated with the quality of the endometrium.

Chorionic Gonadotropin↗
PubMed1984

Acrosome reaction of human sperm used for in vitro fertilization.

The acrosomal reaction of human spermatozoa was assessed, according to a triple-stain technique, at the end of a 17-hour capacitation period in the search for a predictive test of sperm efficiency in an in vitro fertilization program. A 400% increase in the acrosomal reaction rate of the living spermatozoa was observed (4.2% +/- 3.2% before incubation versus 16% +/- 11% after incubation). No correlation could be evidenced between the abilities for spermatozoa to react and to fertilize mature human oocytes in vitro, whatever the initial semen quality. The acrosome reaction rate was not enhanced by the presence of the cumulus oocyte complex, by the selection of motile spermatozoa, or by the increase in albumin concentration of the culture medium.

Acrosome↗
PubMed1984

[In vitro parthenogenesis in the human species].

During the examination of some 800 oocytes prior to in vitro fertilization, twelve exhibited evidence of parthogenetic activation. Four of these twelve underwent cleavage, the cleavage of one being normal. In vitro parthenogenesis is compared with two forms of parthenogenesis observed in vivo, namely ovarian teratomas and hydatidiforms moles.

Female↗
PubMed1982

[In vitro fertilization].

The results of 36 follicular punctures for in vitro fertilization (IVF) performed at the Maternity unit of Hôpital Tenon, Paris, between January and June 1981 are reported. To collect a pre-ovulatory ovocyte by follicular puncture through laparoscopy requires extremely accurate monitoring of ovulation to make sure that the ovocyte collected has completed its nuclear and cytoplasmic maturation in vivo. The criteria for puncture time are the beginning of LH plasma peak level in spontaneous cycles and injection of HCG in stimulated cycles. In this series the ovocyte collection rate was 60% on average. Failures were mostly due to the local status of the genital tract in the women selected for attempted IVF, since all of them had permanent tubal sterility consecutive to severe pelvic inflammatory lesions. The percentage of ovocytes found to be mature was higher in spontaneous than in stimulated cycles. Out of 13 pre-ovulatory ovocytes collected, 8 were fertilized in vitro. Four could be transferred into the uterus, resulting in two pregnancies which had to be interrupted at an early stage. IVF demands full availability of the surgical and laboratory teams concerned.

Adult↗
PubMed1982

[Evaluation of the fertility of human sperm by interspecies (man-hamster) in vitro fertilization].

An "in vitro" fertilization test employing zona-free hamster eggs was used to analyse human spermatozoal fertilizing ability. Sperms from 28 men (group 1) whose wives were candidates for "in vitro" fertilization and embryo transfer, and from 5 men belonging to infertile couples (group 2), were evaluated for their ability to penetrate and decondense in zona-free hamster ova. All men had spermiograms in the normal range. A total of 529 eggs were inseminated with spermatozoa from group 1 and the fertilization rate was found to range from 8% to 100% with an average of 57.5%. Of the 130 ova tested with sperm from group 2 individuals, only one showed any evidence of penetration. The fertilization rate and the degree of polyspermy failed to show a significant correlation with sperm concentration in the ejaculate or motility. This cross-species system is a useful additional test to the classic spermiogram and may have a potential value as a diagnostic tool in evaluating human spermatozoal fertilizing capacity, avoiding the ethical and logistical problems associated with fertilization of human eggs "in vitro".

Animals↗