Search PubMed⌕ Search

Biomedical subjects

M Renaud

Publications and source records attributed to M Renaud.

At least 37 records · Page 2Linked to original sources
PubMed1991

[A new approach for transfusion of neocytes: the Neocel system].

Young red cells (neocytes) were prepared in a double transfer pack having a long, narrow separation bag that allows for a density gradient column to be established during centrifugation. The lighter fraction of red cells (neocyte fraction) was then expressed into a second delivery bag. Phthalate ester density distribution curves showed that 87.1% of the neocyte units had greater than 85% enrichment, i.e. more than 85% of the cells had densities lower than the midpoint density of the original red cell unit, thalassemic patients receiving neocytes had an average decrease of 21.1% in red cells per kg/yr as compared to their frozen red cell requirement, and an average of 6.9% fewer transfusions.

Blood Transfusion↗
PubMed1990

Proton and carbon-13 nuclear magnetic resonance spectroscopy of diastereoisomeric 3- and 17 beta-tetrahydropyranyl ether derivatives of estrone and estradiol.

Protection of 3- and 17 beta-hydroxyl groups of estrone and estradiol as tetrahydropyranyl ether derivatives led to mixtures of 2'(R)- and 2'(S)-diastereoisomers which were separated by crystallization (3-tetrahydropyranyl ethers), or by thin-layer chromatography (17-tetrahydropyranyl ethers), and characterized by 1H and 13C nuclear magnetic resonance (NMR). Assignments for NMR signals of estradiol 3,17 beta-ditetrahydropyranyl ether were facilitated by comparison with those of its 15 zeta, 16 zeta-dideuterio analog and by 2D 1H-13C heteroshift correlation experiments. Diastereoisomers of 3-tetrahydropyranyl ether derivatives could be identified through the 13C NMR doublet signals of the anomeric C-2' and the aromatic C-4 carbon atoms in CDCl3. Diastereoisomers of 17-tetrahydropyranyl ether derivatives were recognized from characteristic modifications of 1H NMR signals of H-2', H-6', H-1, H-17, and 18-CH3 protons as well as from the 13C NMR doublet signals corresponding to C-2', C-4', C-6', C-12, C-13, C-16, and C-17 carbon atoms. Low-temperature experiments showed a splitting of the C-2', C-6', and C-17 13C NMR signals of each of the two 17-tetrahydropyranyl ether isomers. The downfield signal (equatorial conformer) of the three resulting doublets was more intense for the 17-tetrahydropyranyl ether 2'(S)-isomer, whereas the upfield signal (axial conformer) was more intense for the 2'(R)-isomer.

Carbon Isotopes↗
PubMed1990

Mitochondrial development during Drosophila oogenesis: distribution, density and in situ RNA hybridizations.

The changes in distribution and density of mitochondria and the level of mitochondrial RNA during Drosophila oogenesis were studied simultaneously in the 3 cell types ie follicle cells, nurse cells and oocyte, making up the egg chamber. Up to stage 6, mitochondrial density (mitochondrial and cellular areas ratio) was elevated and increased similarly in both follicle and nurse cells. Thereafter the mitochondrial density of follicle cells continued to increase and that of the nurse cells declined markedly while the nurse cell mitochondria assembled in dense groups and decreased in size. This can be related to a transfer of nurse cell cytoplasm, including mitochondria, to the oocyte. In the oocyte from stage 4 to stage 7 we observed a significant decrease of the mitochondrial density due to the absence of mitochondrial biogenesis. Then the cytoplasm transfer caused mitochondrial density to increase up to the level found in the nurse cells at the end of oogenesis. The mature oocyte contains enough mitochondria to supply 15,000 somatic cells. Our results strongly suggest that the variations in size, distribution and density of mitochondria relate to the particular energetic requirements of the different cell types during the first half of oogenesis. Later they relate to the developmental requirements of the nurse cells and the oocyte, in particular the storage of mitochondria in the oocyte. The level of mitochondrial RNA was studied through in situ hybridization. Throughout oogenesis the follicle and nurse cell RNA evolved similarly. Up to stage 9, there was no change in RNA densities in these cells, suggesting a correlation with the cell volume and/or the nuclear DNA content. Thereafter the cellular RNA concentration declined rapidly. In the oocyte the RNA concentration evolved differently especially from stage 10 to the end, the RNA density being stabilized. This can be related to the injection of nurse cell mitochondria, followed by their assignment to reserve status. Our results suggest that the mt RNA density is under extramitochondrial control mechanisms.

Animals↗
PubMed1990

Expression of six mitochondrial genes during Drosophila oogenesis: analysis by in situ hybridization.

We have done a comparative analysis of RNA from six mitochondrial genes (rDNA, ND2, COI, COIII, ND4-ND5, Cyt b) during Drosophila oogenesis, using in situ hybridization. This study showed the same variation for each of these transcripts, which is similar to that obtained with the total mitochondrial RNA (Tourmente et al. (1990) Biol. Cell 60, 119-127). A constant RNA density until stage 9, followed by a rapid decline, was observed in follicle and nurse cells. These results confirm those previously obtained (Tourmente et al., (1990) Biol. Cell 60, 119-127), in favor of the existence of a correlation between the mtRNA level and the cell volume and/or the nuclear DNA content, and suggest a global extra-mitochondrial, transcriptional control mechanism. We also show that the relative proportions of the different RNA are similar, whatever the stage and cell type examined, even though the total mtRNA quantity is different. They are comparable to those previously obtained by Northern analysis of Drosophila embryos (Berthier et al. (1986) Nucleic Acids Res. 14, 1400-1412, suggesting a posttranscriptional control independent of the cell type. Surprisingly, we have detected an extra-mitochondrial hybridization for COIII, both in light and electron microscopy. Northern analysis of poly(A)+RNA from ovaries or cultured cells revealed an 1.7 kb extra-mitochondrial RNA, which is probably of nuclear origin.

Animals↗
PubMed1990

Postcataract extraction ptosis: effect of the bridle suture.

Postcataract extraction ptosis is a common complication of cataract surgery. While many factors have been implicated in its etiology, trauma to the superior rectus/levator complex is considered the most important factor. We prospectively evaluated the effect of two superior rectus bridling techniques on the degree and severity of ptosis present three months after cataract surgery. All other potential variables were controlled for. Bridling the tendon of the superior rectus muscle using the direct, subconjunctival (open) approach results in significantly less severe ptosis than the standard technique of indirect transconjunctival (closed) bridling.

Adult↗
PubMed1990

[Development of fetal semiology in North America].

A survey of the emergence of fetal semiology in the 17 editions of the Williams' Textbook of Obstetrics used by North-American medical students since 1900 was carried out. Three periods were identified: 1906-1950: the fetus, seen as a part of its mother, is ignored until birth and is of no interest to the obstetricians. From the fifties', the decrease in maternal mortality and progress in physiology and therapeutics permitted to study the fetus and a greater attention given to the care of the sick newborn. Since 1970, the availability of ultrasonography has contributed in making the fetus the second patient for obstetricians. It is now possible to study its growth, integrity, health, and well-being. Furthermore, the fetus is now accessible to establish a prenatal diagnosis.

Embryonic and Fetal Development↗
PubMed1989

Characterization of rabbit lactate dehydrogenase-M and lactate dehydrogenase-H cDNAs. Control of lactate dehydrogenase expression in rabbit muscle.

Two cDNA clones were isolated, one corresponding to the mRNA coding for lactate dehydrogenase-M (LDH-M), the other to the mRNA coding for lactate dehydrogenase-H (LDH-H). The cDNA inserts consist of the entire open reading frame for LDH-M and a partial sequence, from amino acid 117 to 332, for LDH-H. Using these two clones as probes we demonstrate that: (a) the abundance of mRNA is muscle-type dependent; (b) the ratio M/H subunit for protein and mRNA is well related in the muscles studied; and (c) the M + H mRNA level is not relative to the total LDH activity.

Amino Acid Sequence↗
PubMed1988

A new approach to neocyte transfusion: preliminary report.

A method has been developed using phthalate oils to quality control units of young red cells (neocytes). Neocytes prepared by the NEOCEL system have a mean young red cell enrichment of 90% with only 3.4% less than 80%. Neocytes prepared in a blood cell processor have an average enrichment of 81% with 27% less than 75%. Based on a 12 month period, the patients as a group have received an average of 14% fewer transfusions and an 18% decrease in red cells per kg/yr as compared to frozen red cells.

Blood Component Removal↗
PubMed1988

The right to refuse in Québec: five-year evolution of a new mode of expressing risk.

In this article, the authors trace the outstanding stages in the institutionalization in Québec of the right to refuse, from its conception in 1978 to its application in more than 1200 cases (as of July 1985) since 1981. The major issue over the first five years of application has been the evolution of norms used as guidelines by inspectors in justifying or not justifying a refusal. The notions of danger and of normality of working conditions and personal conditions were widely debated and clarified. As a new mode of expressing risks for workers and a new mode of regulation for the state, the right to refuse has undergone a reduction in its scope through this process.

Accidents, Occupational↗
PubMed1987

[From social epidemiology to the sociology of prevention: 15 years' research on the social etiology of disease].

Social epidemiology is this field of inquiry that regards the role of social and psychological factors in the aetiology of chronic diseases. In his examination of the evolution of the field, the author stresses the reconceptualization efforts that have been done in the 70's and that gave meaning to research on stress, traits or types of personalities and social support. In conclusion, this research tradition is viewed as perhaps overemphasizing the identification of risk factors while underemphasizing the explanation of the conditions under which good health is maintained.

Disease↗
PubMed1986

RNA mapping on Drosophila mitochondrial DNA: precursors and template strands.

Drosophila melanogaster mitochondrial DNA (mtDNA) is closely related to the mammalian and amphibian mtDNA except for gene organization. In Drosophila, genes are distributed in clusters alternatively coded on each strand. Besides the eleven major foreseeable transcripts previously described (MERTEN and PARDUE, 1981, J. Mol. Biol., 153, 1-21), we have characterized two poly A+ transcripts, one major and one minor which could correspond respectively to the ND3 and ND6 reading frames, and 27 poly A+ minor transcripts (0.2 to greater than 3.2 kb) which are distributed along the mtDNA except in the rRNAs, ND 1 and A+ T rich regions. The mapping and length of 25 of these transcripts strongly suggest a precursor role. They would be processed at the level of tRNA or tRNA-like sequences. Most of them are transcribed from the template strand of each gene cluster and their distribution is in agreement with the hypothesis of several transcription origins and terminations located near the extremities of each gene cluster. Quantitatively our results show a large variation in each presumptive mature transcript compared to the other, even in a given gene cluster, suggesting a specific degradation of some of the mature transcripts.

Animals↗
PubMed1986

Cross-blot and cross-dot system: a high-performance system for the detection of antigen-antibody complexes on nitrocellulose.

We present a reliable, simple, and quick system for screening antibody-antigen complexes on nitrocellulose. The apparatus necessary for this system is inexpensive and easy to use, and it can be adapted to blot or dot analysis without any modification. The number of antibody-antigen combinations that can be tested in one experiment ranges from 25 to 31 for blot analysis and from 345 to 600 for dot analysis. This system also offers numerous experimental advantages: it makes it possible to estimate with only one experiment the contribution of the different reaction stages to background noise and so allows unambiguous interpretation of the antibody-antigen reaction. Furthermore, this system can be used for any hybridization experiment on nitrocellulose.

Animals↗
PubMed1986

In situ hybridization at the electron microscope level: localization of transcripts on ultrathin sections of Lowicryl K4M-embedded tissue using biotinylated probes and protein A-gold complexes.

A technique has been developed for localizing hybrids formed in situ on semi-thin and ultrathin sections of Lowicryl K4M-embedded tissue. Biotinylated dUTP (Bio-11-dUTP and/or Bio-16-dUTP) was incorporated into mitochondrial rDNA and small nuclear U1 probes by nick-translation. The probes were hybridized to sections of Drosophila ovaries and subsequently detected with an anti-biotin antibody and protein A-gold complex. On semi-thin sections, probe detection was achieved by amplification steps with anti-protein A antibody and protein A-gold with subsequent silver enhancement. At the electron microscope level, specific labeling was obtained over structures known to be the site of expression of the appropriate genes (i.e., either over mitochondria or over nuclei). The labeling pattern at the light microscope level (semi-thin sections) was consistent with that obtained at the electron microscope level. The described nonradioactive procedures for hybrid detection on Lowicryl K4M-embedded tissue sections offer several advantages: rapid signal detection: superior morphological preservation and spatial resolution; and signal-to-noise ratios equivalent to radiolabeling.

Animals↗
PubMed1985

Hospital system management in France and Canada: national pluralism and provincial centralism.

Since the mid-1960s, France and Canada have developed different ways of managing their hospital systems. In Canada, each provincial government has gradually imposed technocratic control with the aim of planning the allocation of health-care resources. In spite of attempts to do the same in France, the hospital system has grown with few restrictions other than those set by the medical profession itself. Consequently, health expenditures have risen at one of the fastest paces in Europe. The provincial monopoly over hospital care in Canada contrasts with the juxtaposition of local 'cartels' throughout France resulting, for the latter, in a much more uncoordinated system. After a description of each country's hospital system and its historical origins, the advantages and disadvantages of each system are assessed so as to understand current public debate in each country.

Canada↗
PubMed1985

Presence of an allelic EcoRI restriction fragment of the c-mos locus in leukocyte and tumor cell DNAs of breast cancer patients.

Structure of the human c-mos protooncogene in DNAs from breast tumors, leukemic cells, and lymphocytes from normal individuals was analyzed by restriction enzyme digestion and Southern blot. In 6 of 75 breast tumor DNAs, we found an EcoRI 5-kilobase extra band hybridizing with a human c-mos probe containing all of the sequences homologous to v-mos oncogene. This band was also found in lymphocyte DNA from 3 of these patients, indicating a restriction fragment length polymorphism. This polymorphism was not found in a series of 69 lymphocyte DNAs from the unaffected population. Moreover, 1 of 73 leukemic cell DNAs exhibited the 5-kilobase band. These results indicate that this rare polymorphism is significantly more frequently found in patients with breast cancer than in the rest of the population (P less than 0.05, by a chi 2 test with Yates correction.

Alleles↗
PubMed1984

Mastication after surgical reconstruction of the mandibular residual ridge.

A group of thirty-one female denture patients who underwent surgical reconstruction of their deficient residual ridges with ridge extension and skin graft or ridge augmentation with bone graft were evaluated with regard to their masticatory function before surgery, then at 8 months and 12 months post-operative with their new dentures. Two objectives tests of masticatory efficiency were used. The masticatory efficiency index (MEI), based on the size of chewed almond particles, determined the potential capacity of patients to masticate while the masticatory performance (MP) based on the time required to masticate food before swallowing assessed the individual ability of each patient to chew food. A subjective index of difficulty (SD) provided information on the patient's own assessment of chewing difficulty of certain foods selected for their hard texture. The evolution of each index and their interrelationship were statistically evaluated. It was shown that the masticatory performance (MP) and the subjective index of difficulty (SD) both improved significantly during the rehabilitation period and even more rapidly than the masticatory efficiency index (MEI). The discrepancy between the objective and the subjective tests and the overestimation from the patients indicate that the real benefit of the rehabilitation is not limited to improved chewing, but also to an acquired self-confidence in mastication.

Adult↗
PubMed1984

[Isolation of the RNA-poly A+ fraction from mitochondria of Drosophila melanogaster embryos. Incorporation of methionine-35S into newly-synthesized proteins in whole and lysed mitochondria].

The poly A+ RNA fraction of embryos mitochondria of Drosophila melanogaster was prepared by fractionation by oligo dT-cellulose chromatography. It accounted for 5% of total insoluble RNA. 15 bands were identified by electrophoresis, from 500 to 2,000 base pairs. This poly A+ RNA fraction hybridizes with mitochondrial DNA clones. It contains mitochondrial transcripts: messenger RNA and the large ribosomal RNA. The sum of the transcripts (29 kb) exceed the coding capacities of the mitochondrial DNA. Some of the transcripts may be precursors, greater in size, of the mRNA corresponding to a gene. Our results are compared to those previously published (9, 11, 12). The relationship between mitochondrial transcripts and proteins was studied in whole and lysed isolated mitochondria. In the former, incubated in the presence of 35S-methionine, 20 to 30 radioactive bands were identified (M. Wt. 100 to 16 kd). This incorporation was totally inhibited by chloramphenicol. When the mitochondria were opened in the presence of detergent (lysis). 35S-methionine incorporation was markedly enhanced. In all cases the number of proteins identified was greater than the number of potential genes (12). This finding is discussed.

Animals↗