Search PubMed⌕ Search

Biomedical subjects

J Selva

Publications and source records attributed to J Selva.

At least 55 records · Page 3Linked to original sources
PubMed1992

The incidence of chromosomal abnormalities in frozen-thawed mouse oocytes after in-vitro fertilization.

Cryopreservation of mouse oocytes induced a high rate of atresia. Frozen oocytes observed immediately after thawing did not exhibit any alteration in the frequency of chromosomal abnormalities, aneuploidy or polyploidy. After in-vitro fertilization attempts, the cleavage rate of frozen-thawed mouse oocytes was decreased. Cytogenetical observations of inseminated eggs also confirmed this decrease in fertilization rate. First and second cleavages were delayed compared to fresh controls but subsequent development to the 4-cell stage was not altered. Freeze-thawing increased the incidence of chromosomal abnormalities in inseminated oocytes but this only concerned the frequency of triploidy and not monosomic or trisomic aneuploidy. The increase in triploidy seemed to be largely due to the presence of digynic embryos. Second polar body retention seemed to be mainly responsible for this high rate of polyploidy.

Aneuploidy↗
PubMed1991

Chromosome analysis of multipronuclear human oocytes after in vitro fertilization.

Multipronuclear human eggs are frequent after in vitro fertilization. Their chromosome analysis can provide useful information. Before cleavage it can confirm the suspected polyploidy. Among the cleaved multipronuclear eggs it provides an estimation of the incidence of the possible return to diploidy. Ninety-four multipronuclear eggs were fixed at the first, second, or third cleavage according to the air-drying method of Tarkowski with or without colchicine exposure: 60 were successfully analysed. Twelve were stopped before cleavage (six without colchicine treatment and six with colchicine treatment). They were polyploid, confirming the cytological observation. Forty-eight eggs cleaved and were stopped by colchicine treatment and karyotyped. Seventeen eggs (35 per cent) had produced diploid embryos. Mosaicism was frequent (15 cases, 31 per cent). Triploidy was not frequent (8 eggs, 17 per cent). Haploidy constituted the remaining cases (8 eggs, 17 per cent). Our data indicate that the initial count of pronuclei is a reliable test. Multipronuclear one-cell oocytes were confirmed to be polyploid. Furthermore, the developmental capacity of the multipronuclear oocytes is variable. Most of them cleaved. However, many multipronuclear oocytes led to diploid cleaving eggs.

Adult↗
PubMed1991

Cytogenetic study of human oocytes uncleaved after in-vitro fertilization.

Chromosome analysis of oocytes uncleaved after IVF allows the cause of the failure of cleavage to be determined and shows the incidence of chromosome disorders among human oocytes. A total of 198 uncleaved oocytes fixed 40 h after insemination were successfully analysed according to Tarkowski's air-drying method: 78.3% were unfertilized and arrested in metaphase II. Among them, 70% were normal (23,X) and 30% aneuploid (16% were hypohaploid, 14% were hyperhaploid). The incidence of chromosome breaks was 18%. In 12.1% of the oocytes, sperm chromosome condensation appeared premature usually in the G1 phase. This was especially observed in idiopathic infertility (7% of fertilized oocytes versus 2% in tubal infertility cases). In 8.1% of the cases, chromosome analysis showed diploidy which may be interpreted by either an absence of extrusion or a reintrusion of the polar body or by first cleavage failure during mitosis. In 1% of the cases triploidy was observed. Our results show that the main reason for failure of cleavage is related to failure of fertilization (78.3%). However, premature condensation of sperm chromosomes at the G1 phase appears to be quite frequent. This may be involved in the aetiology of some cases of idiopathic infertility. Finally, the high rate of chromosomal disorders (30%) in human oocytes may explain the high rate of chromosomal abnormalities in preimplantation embryos.

Adult↗
PubMed1990

A protocol for satisfying the ethical issues raised by oocyte donation: the free, anonymous, and fertile donors.

A new protocol was developed to provide participants of our oocyte donation program with oocytes donated by donors who were not financially rewarded, were anonymous, and fertile. Each participant provided an oocyte donor selected among fertile friends or family members. The retrieved oocytes were anonymously exchanged between phenotypically matched donor-recipient pairs. In the first 30 months of activity, we obtained 111 embryos suitable for transfer or cryopreservation from 52 retrievals, and 40 embryo transfers (ETs) were performed. Recipients received oral Estradiol-valerate and vaginal micronized progesterone. Fifteen embryos were transferred in 8 ETs conducted after donor-recipient synchronization. This resulted in four pregnancies, all ongoing (ongoing pregnancy rate 50% per transfer). Of the 96 cryopreserved embryos, 82 were thawed for ET, and 45 surviving embryos were transferred in 32 ETs. This resulted in eight pregnancies, with six ongoing or delivered (ongoing pregnancy rate 19% per transfer). The overall ongoing pregnancy rate of 25% per transfer indicates that our approach is a viable method for obtaining donated oocytes while respecting the ethical guidelines that recommended that donation of human gametes should be free, and from anonymous and fertile donors. Furthermore, guaranteeing anonymous oocyte donation had practical importance because, for many volunteer donors, it played a crucial role in their decision to donate.

Adult↗
PubMed1989

Genetic aspects of artificial insemination with donor semen: the French CECOS Federation guidelines.

The genetic problems raised by assisted reproduction using donor gametes (AID) are numerous and often complex. They concern the legitimacy and the appropriate forms of genetic screening for both gamete donors and recipients; the identification of genetic indications justifying the use of this method of reproduction; and ascertainment of the state of health of the conceptus at birth. The experience and guidelines of the French CECOS Federation, which comprises 20 AID treatment centers, are described. The discussion emphasizes the need for an international exchange of view on this subject.

Eugenics↗
PubMed1988

Collection of circulating stem cells and their use for autograft in adults with acute lymphoblastic leukaemia.

The level of peripheral blood granulocyte-monocytic precursors (PB CFU-GM) was studied serially in 10 adult patients with acute lymphoblastic leukaemia (ALL) in early complete remission after induction chemotherapy. The patients were distributed into 2 main groups according to the morphological French-American-British classification: ALL2 and ALL3. Collection of circulating stem cells (CSC) by cytapheresis was performed in 7 of these 10 patients with satisfactory results, except in 2 ALL2 patients, both of whom had chromosome translocation, which could have been a contributing factor. It appears, moreover, that even with 2 or 3 inductions courses, the more intensive the chemotherapy regimen in previously non-treated patients, the higher the peak of PB CFU-GM and the better the collection of CSC. The measurement of CFU-GM is certainly a less effective indicator of pluripotent stem cells in blood than in bone marrow, and it is probably necessary, but sufficient, to inject 5 times more CFU-GM than normally injected in marrow transplants to allow prompt and stable engraftment. The feasibility of this new graft technique seems for the moment undeniable, the main problem in ALL is the risk of relapse.

Adult↗
PubMed1986

[Genetic aspects of artificial insemination. Choice of donors].

Artificial insemination with donors has genetic repercussions which increase with its impact on demography. Genetic control of semen donors offers a possibility of preventing the main genetic handicaps. The French Federation of Human Semen Study and Preservation Centres (CECOS) is currently organizing such a control system. The reasons for this and the modalities of the system are given in this article.

Female↗
PubMed1986

Genetic screening for artificial insemination by donor (AID). Results of a study on 676 semen donors.

We report the results of our ten-year experience in the Centre for Study and Conservation of Human Semen (CECOS) in Paris-Bicêtre. A total of 676 potential semen donors were interviewed by a geneticist and karyotyped; 6.0% were excluded, i.e. 2.6% for a cytogenetic reason and 3.4% for a genic reason. Our experience stresses the subjectivity and difficulty of the exclusion decision. It also shows how useful it is to take into account the recipient's familial pathology when choosing the donor. Finally, it reveals the importance of the geneticist's participation in the functioning of a centre.

Chromosome Aberrations↗
PubMed1986

Hypotrophic and dying-back nerve fibers in Friedreich's ataxia.

Eight patients with Friedreich's ataxia showed profound reduction in the density of large myelinated fibers in sural nerve biopsies. The density of small myelinated fibers was normal, but the axonal size and myelin thickness were reduced. Demyelination, presumably secondary to axonal dysfunction, was observed in 3% of the isolated fibers. There was axonal degeneration, including dying-back axons isolated in three specimens, in 2.6% of the isolated fibers. The low incidence of degenerating fibers did not account for loss of myelinated fibers in children. There is probably a defect in maturation of fibers, followed by a dying-back process.

Adult↗
PubMed1986

[Collection of circulating stem cells during remission after chemotherapy in acute leukemia].

The level of circulating myeloid progenitor cells (CFU-G), considered to be a good index of the quantity of circulating hemopoietic stem cells, was measured in the peripheral blood of 5 patients with acute leukemia as they entered first remission. High levels of circulating CFU-G were found in 4 of these 5 patients, depending on the intensity and the number of courses of induction chemotherapy. Repeated cytaphereses were done on 3 of these patients in order to collect and to cryopreserve circulating stem cells, to be used later for autologous transplantation. We propose a model which calculates the number of cytaphereses sufficient to obtain a level of 10(5) CFU-G/kg of weight, considered necessary to achieve a good hemopoietic reconstitution after transplantation.

Acute Disease↗
PubMed1985

Peripheral nerve involvement in children with chronic cholestasis and vitamin E deficiency. A clinical, electrophysiological and morphological study.

Seven children with early onset cholestasis who developed signs of peripheral neuropathy were investigated before and after one and a half to three years of treatment by vitamin E. This neuropathy appeared to be due to neuronoaxonal degeneration, but unusual Schwann cell inclusions were also observed. Although the treatment stabilized or improved the condition of all patients, no striking changes were noted neither in the EMG nor in the second nerve biopsy of a patient treated for three years. As the pathological process concerned it is probably both a developmental disorder and a degenerative phenomenon, substitutive vitamin E treatment should be proposed very early in life.

Adolescent↗
PubMed1983

A new method for automatic metaphase finding adaptable to different chromosome preparations.

A FORTRAN computer program, running on a Digital PDP 11-34 minicomputer, has been developed for use in conjunction with a Cambridge Quantimet 720 image analyzer for the investigation of metaphase preparations in routine cytogenetics. During a short initiation phase the program is adapted to the type of metaphase being analyzed. The program is fast and its performance is good, even at low microscopic magnifications. It has other uses in biology for all investigations and characterizations of small distinct elements widely spread within a preparation (e.g., autoradiography, bacteriology).

Chromosome Banding↗
PubMed1983

Progressive centripetal degeneration of axons in small fibre diabetic polyneuropathy.

A clinicopathological study is presented of 5 patients with a pseudosyringomyelic dissociation of sensory loss and severe autonomic disturbances related to diabetic polyneuropathy. Sensory loss which followed a pattern that suggested a length-related degeneration of fibres was associated with spontaneous pains in 3 patients. Plantar ulcers and neurogenic arthropathies were also present in 3 patients. The pathological changes in sural nerve biopsies included a severe loss of unmyelinated and small myelinated axons which appeared to be involved earlier than larger myelinated fibres. Distal degeneration of single fibres with subsequent axonal sprouting from the proximal axon was demonstrated in all patients. This severe axonal neuropathy was associated with primary and secondary segmental demyelination. Our observations are consistent with a progressive centripetal degeneration of axons in predominantly sensory diabetic polyneuropathy.

Adult↗
PubMed1983

Different patterns of uremic polyneuropathy: clinicopathologic study.

Ten patients with a uremic polyneuropathy were investigated. Chronic renal failure was associated with a variety of neuropathies, including an acute axonal neuropathy, a progressive axonal neuropathy with secondary segmental demyelination, and a predominantly demyelinative neuropathy. All patterns were associated with distal degeneration of fibers evidenced by axonal sprouting observed on single-fiber preparations. The etiology of such variations in pathology of uremic neuropathy is still not clearly understood.

Adolescent↗