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Biomedical subjects

C Mathieu

Publications and source records attributed to C Mathieu.

At least 145 records · Page 8Linked to original sources
PubMed1994

[Therapeutic hopes in excretory azoospermia and genetic risks in congenital aplasia of the vas deferens].

Therapeutical solutions now can be proposed to some excretory azoospermia, using in vitro-fertilization with epididymal sperm. The encouraging results obtained with this new approach should be analyzed with the genetic risk, sometimes encountered in the specific form of azoospermia due to the congenital absence of the vas deferens. This abnormality is to day supposed to represent a moderate form of cystic fibrosis (CF), corresponding to a genital phenotype of this disease. This suggestion has been firstly induced by similar anatomical findings in the male individuals presenting a classical form of CF. The hypothesis has mainly been confirmed by the real progress in the genetic analysis of this disease. So an abnormally high percentage of known mutations of CF has been demonstrated in the patients with congenital absence of vas deferens. Other arguments such as positive sweat chloride tests, high percentage of sinusitis or presence of anti-pseudomonas antibodies, reinforce this hypothesis. It is the reason why a clinical and biological check-up, prior to any decision of therapy for infertility, in this specific indication should be done in order to propose a genetic counselling to the couple.

Adult↗
PubMed1993

Lack of disease recurrence in diabetic BB/Pfd rats after syngeneic islet transplantation.

Restimulation of autoreactivity in two different BB rat sublines of the same origin (Ottawa, Canada) was investigated by syngeneic islet transplantation into diabetic animals. Despite identical methods and conditions recurrence of hyperglycaemia was observed in BB/OK rats (Karlsburg, Germany) but not in BB/Pfd rats (Leuven, Belgium). Pancreatic morphology at the time of transplantation revealed significant differences in islet volume density and the degree of insulitis. Additionally, marked differences in the phenotypical composition of cells infiltrating the islets were observed. A loss of autoimmune memory in BB/Pfd rats is discussed as a probable reason for the lack of disease recurrence in those animals.

Animals↗
PubMed1993

[Value of plasma progesterone (rapid assay) during ovarian stimulation for in vitro fertilization using LHRH agonists and hMG].

We have studied all the cycles (= 276) induced for in vitro fertilization using a LHRH agonist and the hMG (113 short protocols, 163 long protocols) from 01.90 to 07.90 to know the plasmatic profiles of the estradiol (E2), of the LH and specially of the progesterone (P) between J-7 and the day of the hCG (= J0). We observe in the short protocol an elevation (effect flare up) and afterwards a fall concomitant of the P and of the LH up to J-5, J-6 (effect of pituitary down regulation), in the short and long protocols a progressive elevation of J-3 up to J0 of the P parallel to E2, so that the LH remain stable or decrease. The LH of J0 is higher in short protocol than in long protocol (10.14 +/- 2.9 versus 4.72 +/- 1.3 Ul/l, p < 0.00001). We found the same progressive elevation of the P of J-3 up to J0 in pregnant and not pregnant patients. The surveillance of the P coupled to the E2 and to the follicular ultrasonography could help in the choice of the day of the hCG and avoid a post-maturity of oocyte. The consequences of the elevation of P In the morning of J0 have been study for P levels < 1 ng/ml (73 cases) and P > or = 1 ng/ml (203 cases) and afterwards for progressive elevation of P levels (1.5-2-2.5-3 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Amplification of substoichiometric recombinant mitochondrial DNA sequences in a nuclear, male sterile mutant regenerated from protoplast culture in Nicotiana sylvestris.

A Nicotiana sylvestris plant regenerated from protoplast culture was found to be mutated in both the mitochondrial (mt) and nuclear genomes. The novel mt DNA organization, called U, is due to the amplification of recombinant substoichiometric DNA sequences that preexist in the parent line. The recombination event involves two 404 bp repeats, which hybridize to a 2.1 kb transcript. Although the sequence of both repeats was not altered by the recombination, an additional transcript of 2.5 kb was detected in U mitochondria. In addition to this mitochondrial reorganization, the protoclone carried a recessive nuclear mutation conferring male sterility (ms4). A possible role of ms4 in the appearance of the U mt DNA organization was investigated by introducing this gene into normal N. sylvestris cytoplasm. No mt DNA change could be found in homozygous ms4/ms4 plants of the F2 generation.

Amino Acid Sequence↗
PubMed1992

Motility and fertilizing capacity of epididymal human spermatozoa in normal and pathological cases.

OBJECTIVE: To investigate different factors involved in the outcome of in vitro fertilization (IVF) with epididymal spermatozoa in cases of vas deferens agenesis, with particular emphasis on sperm movement parameters. DESIGN: Prospective study in which sperm movement characteristics, level of puncture, and sperm preparation technique were studied relative to the outcome of IVF. SETTING: Département de Gynécologie, Oncologie Gynécologique, Sénologie, Médecine de la Reproduction, Hôpital Edouard-Herriot, Lyon France. PATIENTS: Thirteen couples underwent 15 IVF cycles. In 14 cycles (12 patients) epididymal spermatozoa could be recovered by surgical punctures. Epididymides were taken from 10 subjects in state of cerebral death to study epididymal spermatozoa under physiological status of the epididymis. RESULTS: The cleavage rate in IVF was low (25/158: 15.8%). In seven cases, embryo transfer was possible, leading to two twin pregnancies (4 infants born). Fertilization could be achieved with spermatozoa from the epididymis caput. Motility was paradoxically higher in the proximal epididymis than in the distal epididymis. In healthy epididymides, spermatozoa collected from the caput did not exhibit any progressive motility, whereas progressive motility was always present in the epididymis corpus. CONCLUSIONS: Our study showed that forward motility could be observed in the epididymis caput in patients with congenital absence of the vas deferens and that fertilization and ongoing pregnancies could be obtained from caput spermatozoa. On the other hand, in physiological status of the epididymis, forward motility was observed only as from the corpus area, confirming observations in other species.

Adult↗
PubMed1992

Variations in the glycoforms of serum alpha 1-antichymotrypsin in liver diseases and after liver transplantation.

1. Using crossed immunoaffinity electrophoresis with free concanavalin A in the first dimension, we studied the microheterogeneity of alpha 1-antichymotrypsin due to various glycoforms in sera from patients with various liver diseases and after liver transplantation. 2. Studies by isoelectric focusing and immunoblotting and by crossed immunoelectrophoresis without concanavalin A in the first dimension allowed us to show that there is no dramatic variation in electrophoretic heterogeneity of alpha 1-antichymotrypsin in the serum of patients with liver diseases or after liver transplantation when compared with that of normal subjects. Therefore the heterogeneity observed in crossed immunoaffinity electrophoresis is due to various interactions with concanavalin A. 3. The results were expressed as the ratio of concanavalin A non-reactive glycoforms plus concanavalin A weakly reactive glycoforms to concanavalin A reactive glycoforms, called R alpha 1-ACT. R alpha 1-ACT was significantly higher in patients with cirrhosis (n = 53) when compared with normal subjects (n = 30). The median R alpha 1-ACT was 1 (range 0.72-1.25) in normal subjects. It was 1.6 (range 1.18-3.02), 1.45 (range 0.65-4.12) and 2.24 (range 1.03-19) in cirrhosis of Child's grade A, B and C, respectively. There was a dramatic decrease in glycoforms with mostly biantennary glycans in some patients with Child's grade C cirrhosis. Serum levels of alpha 1-antichymotrypsin were lower than normal only in some patients with Child's grade C cirrhosis. 4. Among the patients with acute viral hepatitis studied (n = 17), five were studied longitudinally.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

1,25-Dihydroxyvitamin D3 prevents insulitis in NOD mice.

The active form of vitamin D, 1,25(OH)2D3, can prevent various forms of experimentally induced autoimmune disorders. The aim of this study was to confirm these findings in NOD mice that spontaneously develop an autoimmune type of diabetes mellitus. Therefore, the effect of a long-term 1,25(OH)2D3 treatment on the incidence of insulitis, the histological lesion preceding diabetes, was studied. Forty-three NOD mice were treated with 1,25(OH)2D3 (5 micrograms/kg) i.p. every other day from age 21 days on, when no insulitis was present yet. At day 100, 16 control mice receiving the treatment vehicle (arachis oil) had an incidence of insulitis of 75%, whereas only 41% of the 1,25(OH)2D3-treated animals developed insulitis (P < 0.025). Calcemia, determined 24 h after the last 1,25(OH)2D3 injection was 2.5 +/- 0.1 mM, which was higher than in control animals (2.3 +/- 0.1 mM), but was well tolerated. Cellular immunity, as assessed with the mixed lymphocyte reaction performed at day 100, was not impaired significantly. This study demonstrates that long-term treatment with high doses of 1,25(OH)2D3 is able to decrease the incidence of insulitis in spontaneous autoimmune diabetes without major side effects.

Animals↗
PubMed1991

Developmental expression of fibrillarin and U3 snRNA in Xenopus laevis.

Fibrillarin is one of the protein components that together with U3 snRNA constitute the U3 snRNP, a small nuclear ribonucleoprotein particle involved in ribosomal RNA processing in eucaryotic cells. Using an antifibrillarin antiserum for protein detection and a fibrillarin cDNA and a synthetic oligonucleotide complementary to U3 snRNA as hybridization probes, the expression of these two components has been studied during Xenopus development. Fibrillarin mRNA is accumulated early in oogenesis, like many other messengers, and translated during oocyte growth. Fibrillarin protein is thus progressively accumulated throughout oogenesis to be assembled with U3 snRNA and used for ribosome production in the amplified nucleoli. After fertilization, the amount of U3 snRNA decreases while the maternally accumulated fibrillarin mRNA is maintained and utilized to produce more protein. After the mid-blastula transition, stored fibrillarin is assembled with newly synthesized U3 snRNA and becomes localized in the prenucleolar bodies and reforming nucleoli.

Animals↗
PubMed1990

Transfers of frozen-thawed human embryos in cycles stimulated by HMG.

A total of 130 transfers of frozen-thawed (F-T) human embryos was carried out after moderate ovarian stimulation with human menopausal gonadotrophin (HMG). Embryos were replaced 3 days after the spontaneous luteinizing hormone (LH) surge or 4 days if ovulation was induced by human chorionic gonadotrophin (HCG). Embryos were thawed a few hours prior to transfer. One-hundred-and-twenty-three transfers were effective and 23 pregnancies were achieved. The rate of ongoing pregnancies per transfer was 17.9% (22/123). The survival rate of embryos originating from cycles stimulated by a combination of an LHRH analogue and HMG in a long protocol (LA-HMG protocol) was significantly lower when compared with the rate of embryos retrieved from clomiphene citrate-HMG (CC-HMG protocol) stimulated cycles (52 versus 67%, P less than 0.05). When fresh embryos originated from cycles stimulated with an LHRH analogue and HMG in a short protocol (SA-HMG protocol), the survival rate was not affected (59 versus 67%, NS). Although the difference was not significant, the ongoing pregnancy rate per transfer according to the three protocols from which the embryos originated seemed to be better with the SA-HMG protocol: 16% with the CC-HMG protocol, 14.5% with the LA-HMG protocol versus 27.6% with the SA-HMG protocol. The success rate was independent of the number of F-T transferred embryos if at least one embryo with 100% intact blastomeres was replaced.

Cryopreservation↗
PubMed1990

Molecular cloning of Xenopus fibrillarin, a conserved U3 small nuclear ribonucleoprotein recognized by antisera from humans with autoimmune disease.

Autoantibodies against U3 small nuclear ribonucleoprotein are associated with scleroderma autoimmune disease. They were shown to react with fibrillarin, a 34- to 36-kilodalton protein that has been detected in all eukaryotes tested from humans to yeasts. We isolated a 1.6-kilobase cDNA encoding fibrillarin from a Xenopus laevis cDNA library. The protein contains a 79-residue-long Gly-Arg-rich domain in its N-terminal region and a putative RNA-binding domain with ribonucleoprotein consensus sequence in its central portion. This is the first report of cloning of fibrillarin, and the deduced protein sequence is in agreement with the involvement of the protein in a ribonucleoprotein particle.

Amino Acid Sequence↗
PubMed1989

Protein kinase NII and the regulation of rDNA transcription in mammalian cells.

Transcription of ribosomal RNA genes is generally accepted to correlate with cell growth. Using primary cultures of adult bovine aortic endothelial (ABAE) cells, we have shown that transcription of rDNA in confluent cells falls to 5% of the transcription level in growing cells. Protein kinase NII appears to be a limiting factor to promote rDNA transcription in isolated nuclei of confluent cells. Protein kinase NII was detected by immunocytochemistry in the cytoplasm, nuclei and nucleoli of growing cells while it was no longer present in nucleoli of confluent cells. The kinase activity, in isolated nuclei, was estimated by endogenous phosphorylation of a specific substrate, nucleolin. A 10% residual activity was present in confluent cell nuclei compared to growing cell nuclei. Concomitantly, the transcription 'in vitro' of rDNA in the corresponding nuclei was also highly reduced (by 85%). Addition of exogenous protein kinase NII to confluent cell nuclei induced a strong increase in the phosphorylation of specific proteins including nucleolin. In parallel, the transcription of rDNA was increased by a factor of 5, to nearly the level observed in nuclei prepared from growing cells. These data suggest that, in confluent cells, factors necessary for rDNA transcription machinery are present but inactive in the nucleolus and that the phosphorylation of one or several of these factors (nucleolin, topoisomerase I,...) by protein kinase NII is a key event in the regulation of rDNA transcription.

Alkaline Phosphatase↗