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Biomedical subjects

B Lejeune

Publications and source records attributed to B Lejeune.

At least 55 records · Page 3Linked to original sources
PubMed1996

Comparisons of intravaginal and intrauterine insemination of bitches with fresh or frozen semen.

To compare the importance of the route of insemination when using fresh or frozen semen, six groups of five bitches were inseminated either into the uterus (groups 4, 5 and 6) or the vagina (groups 1, 2 and 3) with fresh (groups 1 and 4) or frozen semen (groups 2, 3, 5 and 6). The fresh semen was collected when needed from the same dog. The frozen semen used in groups 2 and 5 was obtained from seven dogs on the same day, and pooled and processed simultaneously so that the groups were inseminated with exactly the same semen. The frozen semen used in groups 3 and 6 was obtained from different dogs and processed independently to evaluate not only the effect of the route of insemination but also the potential effect of the dog. The mean concentration of the fresh semen was 310 x 10(6) spermatozoa/ml, its motility was greater than 80 per cent and the percentage of normal live spermatozoa was 80 to 92 per cent. The mean spermatozoal concentration of the frozen semen was 200 x 10(6) spermatozoa/ml, its motility was greater than 60 per cent and the percentage of normal live spermatozoa was 80 per cent. In all the groups there were fewer than 15 per cent abnormal spermatozoa. The animals inseminated with fresh semen received significantly more spermatozoa than the others. The bitches were inseminated twice, three and five days after the estimated peak of luteinising hormone, with a total volume of 5 ml for the vaginal inseminations and 2 ml for the intrauterine inseminations. Sixty per cent of the bitches inseminated with frozen semen and 100 per cent of the bitches inseminated with fresh semen became pregnant, irrespective of the insemination technique used.

Animals↗
PubMed1996

Two essential steps for a successful intracytoplasmic sperm injection: injection of immobilized spermatozoa after rupture of the oolema.

A total of 740 cycles of intracytoplasmic sperm injection (ICSI) were performed: 625 cycles when < 6 x 10(5) total motile spermatozoa were harvestable from the ejaculate and 115 cycles in cases with a history of previous fertilization failure after classic in-vitro fertilization or subzonal sperm injection. An average of two pronuclei were observed in 63% of the injected oocytes, allowing 725 transfers of a maximum of three embryos (98%). Of 214 pregnancies initiated, 179 were established (25% of ICSI attempts). Because the fertilization rates from our initial 80 ICSI cycles were 2-fold less than those achieved previously, we changed the injection procedure and analysed, in 740 ICSI attempts, the importance of interfering technical factors and how to establish a successful ICSI programme. A remarkable change in the fertilization rate up to 68% (595 cycles) occurred when two steps in the injection procedure were performed well, i.e. immobilization of the spermatozoon and placement of the spermatozoon into the ooplasm after cytoplasmic aspiration into the pipette until oolema rupture. This immobilization, by touching the tail with the pipette, is mandatory for increasing the percentage of fertilization, even with totally non-motile spermatozoa (41%). Because aspiration of the cytoplasm is an invasive part of the ICSI procedure and influences the quality of the embryos, it is essential to reduce the amount of cytoplasm drawn into the pipette. This could be attained by using a spikeless injection pipette with the smallest possible internal diameter.

Cytoplasm↗
PubMed1996

Fertilizing ability of immotile spermatozoa after intracytoplasmic sperm injection.

Sometimes spermatozoa from ejaculate, epididymis or testis show a total absence of motility. For some patients, however, very few spermatozoa with very poor motility can be found after several hours of incubation (initially immotile spermatozoa). Other samples show no motility at all even after extended culture (totally immotile spermatozoa). Intracytoplasmic sperm injection (ICSI) is the only method available to select and retrieve a single immotile or initially immotile spermatozoon and inject it into the oocyte. A total of 103 patients with asthenozoospermia underwent ICSI in this study. It was shown that initially immotile and totally immotile spermatozoa, whatever their origin, have the capacity to fertilize an oocyte after ICSI. No significant difference could be observed between the fertilizing capacity of testicular or epididymal spermatozoa. Totally immotile ejaculated spermatozoa, however, fertilized significantly fewer oocytes after ICSI when compared with initially immotile ejaculated spermatozoa. Embryos of lower quality tended to be produced when totally immotile spermatozoa of any origin were used, compared with embryos resulting from initially immotile spermatozoa. Ongoing pregnancies were conceived after ICSI with initially immotile spermatozoa from any origin and totally immotile spermatozoa retrieved from testis only. One biochemical pregnancy was the result of embryo transfer after ICSI with totally immotile ejaculated spermatozoa. No supernumerary embryos could be cryopreserved for patients with totally immotile spermatozoa from ejaculate or epididymis. For a Kartagener patient, subzonal insemination (SUZI) seemed to be a better approach for obtaining fertilization and pregnancy than ICSI because no fertilization occurred after ICSI on sibling oocytes. Hence a healthy pregnancy was obtained after SUZI.

Cryopreservation↗
PubMed1995

A phylogenetic analysis of monocotyledons based on the chloroplast gene rps4, using parsimony and a new numerical phenetics method.

We have sequenced the chloroplast gene rps4 of 72 species; the sequence of 6 more species was found in the databanks. The 78 species were chosen so as to be representative of two taxonomic levels: the family, with 39 Poaceae, and the class, with 28 additional monocot species. Eleven dicots and other land plants were used as outgroups to the monocots. The 78 sequences were aligned by eye. Phylogenetic reconstruction was performed using the Wagner parsimony method: our first results were in contradiction with classical systematics, due to a local minimum. We then used the results obtained with the new distance method Anataxis to redraw a new tree and carry on further the parsimony calculations starting from this Anataxis tree. Up to 20,000 most parsimonious trees were thus obtained. The robustness of our results was checked by the bootstrap test and decay analyses. The Anataxis and the strict consensus tree fitted the general features of land plant evolution. Some of our results concerning relationships within the monocots corroborated those obtained with the chloroplast gene rbcL. Both genes raise questions concerning the monocot superorders as defined in a previous classification. This study proves the rps4 gene to be a useful phylogenetic tool within the Poaceae family and the Monocotyledonae order.

Base Sequence↗
PubMed1995

Hydrosalpinges in in-vitro fertilization: an unfavourable prognostic feature.

The aim of this study was to determine whether the presence of a hydrosalpinx influences in-vitro fertilization (IVF) prognosis. Comparisons were made between 69 IVF cycles in 37 patients carrying hydrosalpinges (hydrosalpinx group) and 67 IVF cycles in 41 patients without tubes or surgically sterilized (control group). Twenty-two patients carrying hydrosalpinges underwent salpingectomy or salpingoplasty (operated group); they then underwent 42 IVF trials which were compared with the two former groups. In the hydrosalpinx group, pregnancy rates by oocyte retrieval were 10.1% for clinical and ongoing pregnancies. In the control group, the corresponding pregnancy rates were 23.0 and 21.3% respectively. The implantation rate per embryo was 4.2% for clinical and ongoing pregnancies in the hydrosalpinx group and 11.0 and 10.4% respectively in the control group. The operated group had pregnancy rates of 38.1% for clinical pregnancies and 31.0% for ongoing pregnancies, with implantation rates of 17.4 (clinical) and 14.8% (ongoing) respectively. Pregnancy and implantation rates were statistically lower in the hydrosalpinx group as compared with controls and with the operated group. The differences between control and operated groups were not significant. In conclusion, the presence of a hydrosalpinx is thus associated with poor prognosis in IVF treatment. Surgical correction of such lesions appears to restore high success rates.

Adult↗
PubMed1995

A randomized trial for the treatment of mild iodine deficiency during pregnancy: maternal and neonatal effects.

One hundred and eighty euthyroid pregnant women were selected at the end of the first trimester of gestation on the basis of biochemical criteria of excessive thyroid stimulation, defined as supranormal serum thyroglobulin (TG > 20 micrograms/L) associated with a low normal free T4 index (< 1.23) and/or an increased T3/T4 ratio (> 25 x 10(-3)). Women were randomized in a double blind protocol into three groups and treated until term with a placebo, 100 micrograms potassium iodide (KI)/day, or 100 micrograms iodide plus 100 micrograms L-T4/day. Parameters of thyroid function, urinary iodine excretion, and thyroid volume were monitored sequentially. Neonatal thyroid parameters, including thyroid volume by echography, were also assessed in the newborns from mothers of the three groups. In women receiving a placebo, the indices of excessive thyroid stimulation worsened as gestation progressed, with low free T4 levels, markedly increased serum TG and T3/T4 ratio. Serum TSH doubled, on the average, and was supranormal in 20% of the cases at term. Urinary iodine excretion levels were low, around 30 micrograms/L at term. The thyroid volume increased, on the average, by 30%, and 16% of the women developed a goiter, confirming the goitrogenic stimulus associated with pregnancy. Moreover, the newborns of these mothers had significantly larger thyroid volumes at birth as well as elevated serum TG levels. In both groups of women receiving an active treatment, the alterations in thyroid function associated with pregnancy were markedly improved. The increase in serum TSH was almost suppressed, serum TG decreased significantly, and changes in thyroid volume were minimized (group receiving KI) or almost suppressed (group receiving KI combined with L-T4). Moreover, in the newborns of the mothers in the two groups receiving an active treatment, serum TG was significantly lower, and thyroid volume at birth was normal. The effects of therapy were clearly more rapid and more marked in the group receiving a combination of T4 and KI than in the women receiving KI alone. The differences could be partly attributed to the slightly higher amount of iodine received by women in the combined treatment. However, the main benefits of the combined treatment were almost certainly attributable to the hormonal effects of the addition of L-T4. Furthermore, the study demonstrated that the administration of T4 did not hamper the beneficial effect of iodine supplementation. In conclusion, the present work emphasizes the potential risk of goitrogenic stimulation in both mother and newborn in the presence of mild iodine deficiency.(ABSTRACT TRUNCATED AT 400 WORDS)

Double-Blind Method↗
PubMed1994

Mitochondrial DNA variability detected in a single wheat regenerant involves a rare recombination event across a short repeat.

The mitochondrial genome of the selfed progeny of a plant regenerated from long-term somatic tissue culture displays specific structural rearrangements characterized by the appearance of novel restriction fragments. A mitochondrial DNA library was constructed from this selfed progeny in the SalI site of cosmid pHC79 and the novel fragments were subsequently studied. They were shown to arise from reciprocal recombination events involving DNA sequences present in the parental plant. The regions of recombination were sequenced and the nucleotide sequences were aligned with those of the presumptive parental fragments. We characterized an imperfect short repeated DNA sequence, 242 bp long, within which a 7-bp DNA repeat could act as a region of recombination. The use of PCR technology allowed us to show that these fragments were present in both parental plants and tissue cultures as low-abundance sequence arrangements.

Base Sequence↗
PubMed1993

The nad6 gene and the exon d of nad1 are co-transcribed in wheat mitochondria.

The exon d of nad1 is located 993 bp upstream of the nad6 gene in the wheat mitochondrial genome. Transcription analyses of both sequences (nad1 exon d and the nad6 gene) were done by Northern hybridization using RNA from wheat seedlings and tissue cultures derived from immature embryos. A complicated pattern was generated with a probe including exon d of nad1 and the whole nad6 gene. An 0.71-kb transcript is specific to nad1 exon d whereas a 1.2-kb transcript is specific to the nad6 gene. Three larger transcripts hybridize to both probes suggesting that nad1 exon d and nad6 are co-transcribed. This co-transcription has been directly demonstrated by cDNA synthesis on mtRNAs and sequencing of the PCR amplification product.

Base Sequence↗
PubMed1993

Serum levels of intact human chorionic gonadotropin (HCG) and its free alpha and beta subunits, in relation to maternal thyroid stimulation during normal pregnancy.

The main objective of the present study was to present additional evidence of the potentially important thyrotropic role of hCG to regulate the maternal thyroid gland during normal pregnancy. Sequential determinations (first and last trimesters) of intact hCG, free alpha and beta-hCG subunits concentrations (using monoclonal IRMAs), and assessment of parameters of thyroid function and thyroid volume were carried out in 62 pregnant women who exhibited during the first trimester of gestation low TSH levels (< or = 0.20 mU/L), and compared to 276 pregnant women with normal TSH levels. The prevalence of having low serum TSH represented 18% of all pregnancies, with almost one half of cases who transiently had undetectable TSH levels. Lowering of TSH was associated with high hCG levels, and occurred primarily during the first trimester. About 10% of women with low TSH presented transient gestational thyrotoxicosis, frequently associated with vomiting. In comparison to control subjects, women with a suppressed serum TSH had significantly and markedly higher intact hCG and free beta-hCG subunit concentrations. The results suggest that TSH reduction may result from a relative oversecretion of both intact hCG and free beta-hCG subunits, compatible with three hypotheses: a) transient overexpression of the beta-hCG gene, leading to enhanced production of hCG heterodimer; b) increased glycosylation of circulating hCG, with in turn a prolonged half life; c) larger syncytiotrophoblast mass with increased hCG production.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Antithyroid antibodies underlying thyroid abnormalities and miscarriage or pregnancy induced hypertension.

OBJECTIVE: To assess whether asymptomatic abnormalities, including thyroid auto-antibodies, were associated with an abnormal miscarriage rate or a poor obstetric outcome. DESIGN: Prospective study of thyroid auto-antibodies and thyroid function in an unselected obstetric population. SETTING: Saint-Pierrie Hospital, Brussels, Belgium. SUBJECTS: Seven hundred and thirty consecutive pregnant women attending the antenatal clinic. MAIN OUTCOME MEASURES: Miscarriage and pregnancy induced hypertension. RESULTS: Elevated antithyroperoxidase (TPO-Ab) and antithyroglobulin (TG-Ab) antibody titres are associated with an increased miscarriage rate. Also, asymptomatic thyroid abnormalities, mainly abnormal echo-structure but not antithyroid antibodies, are associated with pregnancy induced hypertension. CONCLUSION: The presence of thyroid auto-antibodies during pregnancy constitutes a marker of increased risk of miscarriage and poor obstetric prognosis.

Abortion, Spontaneous↗
PubMed1992

The wheat mitochondrial genome contains an ORF showing sequence homology to the gene encoding the subunit 6 of the NADH-ubiquinone oxidoreductase.

A region of the mitochondrial (mt) DNA of wheat was studied because of its homology with other plant mtDNAs. Sequence analysis revealed an open reading frame encoding a polypeptide of 247 amino acids. Comparison of the sequence of the putative polypeptide with the protein sequence data of the Swiss-Prot library reveals homology with subunit 6 of the NADH-ubiquinone complex of mitochondria from Marchantia polymorpha, Podospora anserina, Chlamydomonas reinhardtii and of chloroplasts from M. polymorpha and Oryza sativa. No similarity was detected when compared with the subunit 6 of animal mitochondria, probably due to the rapid evolution of the sequence. A single 1.2 kb transcript appears in northern RNA blots. We found 15 edited sites of which only 13 give amino acid changes. This is the first report of a mt nad6 gene in higher plants.

Amino Acid Sequence↗
PubMed1992

The higher plant nad5 mitochondrial gene: a conserved discontinuous transcription pattern.

The single copy nad5 gene has been identified in the mitochondrial genomes of cauliflower, chicory, potato, fennel, and common bean. In these five dicot species the same organization as in Oenothera, Arabidopsis, wheat, and maize has been found for the gene: it consists of five exons organized into three independent groups. The first group comprises exons I and II, separated by a highly conserved group II intron, while the second group consists of exon III only. In the third group exons IV and V are separated by a group II intron of variable, species-specific, length. Transcription analysis of the nad5 gene in chicory and in cauliflower shows that the five exons are assembled as a mature mRNA through intermolecular interactions and multiple splicing events. Comparison of transcription in the gene with that of wheat and maize suggests that a common mechanism exists in higher plants for nad5 transcript processing.

Base Sequence↗
PubMed1992

Maternal and neonatal thyroid function at birth in an area of marginally low iodine intake.

Thyroid function was evaluated in cord serum of healthy full-term newborns and compared to that of mothers immediately after parturition. The study was carried out in an area without overt iodine deficiency, but with a marginal iodine supply (less than 100 micrograms/day in 80% of women). The aim of the study was to delineate the interrelationships between the thyroid statuses of mother and child at birth. Maternal thyroid function was characterized at delivery by relative hypothyroxinemia; increased T3/T4 ratios, indicating preferential T3 secretion; slightly increased TSH levels within the normal range in 97% of women; increased serum thyroglobulin (TG) values, which were above normal in 60% of women; and also goiter formation in almost 10% of women. The findings indicated glandular stimulation and confirmed our earlier reports that pregnancy constitutes a stress for the maternal thyroid economy, enhanced by the limited availability of iodine in the diet. By contrast, newborns showed a strikingly distinct pattern: there was no relative hypothyroxinemia and free T4 levels were significantly higher than in the respective mothers (19.4 vs. 14.7 pmol/L; P less than 0.001). In spite of these differences, however, mean neonatal TSH and TG levels were significantly higher than maternal values, respectively 6.0 vs. 1.9 mU/L for TSH (P less than 0.001) and 70 vs. 40 micrograms/L for TG (P less than 0.001). Furthermore, neonatal TG and TSH levels increased in parallel and were highly correlated with maternal data, suggesting a regulatory link between both thyroid economies. The results suggested that the common regulatory link is the limited availability of the iodine supply. In conclusion, the present study demonstrates that even in conditions with a marginally low iodine intake, pregnancy constitutes a stimulus for both the maternal and newborn thyroids. Changes in both groups are associated and the abnormalities in TSH and TG are amplified in the newborns. The TSH and TG alterations at birth in full-term healthy newborns, associated with similar alterations in maternal thyroid function, provide evidence for a common stimulatory factor, relative iodine deficiency. The data emphasize the hypersensitivity of neonatal thyroid function to marginal iodine deficiency and point to the need to increase the iodine supply in groups at risk, such as women during pregnancy, and also newborns in the perinatal period.

Cohort Studies↗