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Biomedical subjects

F Gasser

Publications and source records attributed to F Gasser.

12 recordsLinked to original sources
PubMed1992

Gonadotropins induce accumulation of insulin-like growth factor I mRNA in pig granulosa cells in vitro.

Pig granulosa cells have been shown to synthesize insulin-like growth factor (IGF) I peptide in vitro, and this expression is regulated by gonadotropins via the cAMP pathway. By hybridizing an IGF I cDNA probe with total RNA isolated from pig granulosa cells cultured in vitro, we show that these cells contain two IGF I transcripts of about 0.9 kb and 9 kb in size. Treatment of the cells with gonadotropins (follicle-stimulating hormone, luteinizing hormone) or cAMP agonists (dibutyryl-cAMP, forskolin) induces an accumulation of the transcripts which can be abolished by transcriptional inhibitors, but not by translational inhibitors. We thus provide new evidence that pig granulosa cells are a site of IGF I synthesis, and we conclude that (1) gonadotropins increase IGF I mRNA levels; (2) the accumulation of IGF I mRNA results from an increased transcription; (3) the stimulation of IGF I gene transcription does not require ongoing protein synthesis; (4) these effects of follicle-stimulating hormone can be mimicked by cAMP agonists.

Animals↗
PubMed1991

Complementation of Methylobacterium organophilum mutants affected in pyrroloquinoline quinone biosynthesis genes pqqE and pqqF by cloned Escherichia coli chromosomal DNA.

The hybrid plasmid pBGT3, a derivative of pLA2917 containing a 7.8-kb fragment of Escherichia coli DNA, was found to complement pqqE and pqqF mutants of Methylobacterium organophilum, both impaired in PQQ biosynthesis. The cloned fragment of E. coli DNA did not hybridize with DNA fragments containing pqqE or pqqF previously cloned from M. organophilum. Yet, in M. organophilum mutants, expression of pqqE and pqqF genes from E. coli resulted in a PQQ production estimated at 9-16% of the production observed in M. organophilum wild-type. The growth rate in methanol medium of the complemented M. organophilum mutants was about 60% of that of the wild-type.

Chromosomes, Bacterial↗
PubMed1991

Mutants of Escherichia coli producing pyrroloquinoline quinone.

In glucose minimal medium a PTS- strain of Escherichia coli [delta (ptsH ptsI crr)] could grow slowly (doubling time, d = 10 h). When the population reached 5 x 10(6) to 2 x 10(7) cells ml-1, mutants growing rapidly (d = 1.5 h) appeared and rapidly outgrew the initial population. These mutants (EF mutants) do not use a constitutive galactose permease for glucose translocation. They synthesize sufficient pyrroloquinoline quinone (PQQ) to yield a specific activity of glucose dehydrogenase (GDH) equivalent to that found in the parent strain grown in glucose minimal medium supplemented with 1 nM-PQQ. Membrane preparations containing an active GDH oxidized glucose to gluconic acid, which was also present in the culture supernatant of EF strains in glucose minimal medium. Glucose utilization is the only phenotypic trait distinguishing EF mutants from the parent strain. Glucose utilization by EF mutants was strictly aerobic as expected from a PQQ-dependent catabolism. The regulation of PQQ production by E. coli is discussed.

Aerobiosis↗
PubMed1991

[Evaluation of thyroid function after myocardial infarction].

The myocardial infarction (M.I.) constitutes an exemplary acute severe affection able to modifie hormonal concentrations. The total and unbound thyroid hormones, reverse T3 (rt3), TSH, and cortisolemia were determined in 24 patients during a period of 21 days in order to compare them to different markers of severity of MI. The initial phase of the disease is characterized by low concentrations of total and free T3 and high concentrations of rT3 combined with more often than not normal total and free T4 and TSH values contrasting with an increase in cortisol levels. The abnormalities were more pronounced the day after admission and then progressively amend. There are several statistic relationship between the marker of severity of MI and thyroid hormones. In the same way total T3 is all the more decreased especially since myoglobin, CPK-MB, ST amplitude and ventricle ejection fraction are more disturbed. Severe forms of MI induces a pseudo central thyroid insufficiency with low T3, low T4 and a tendency to TSH decrease. Total T3 blood levels may usefully contribute to the elaboration of an MI severity index.

Adult↗
PubMed1975

[Impression methods].

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Dental Impression Technique↗
PubMedDate not supplied

Changes in serum testosterone levels after myocardial infarction.

To evaluate the effect of a severe non-endocrine disease on testosterone levels we determined the total testosterone (T), free testosterone (fT), myoglobin and myosin plasmatic levels in 18 men at the time of hospitalization for acute myocardial infarction (AMI), and 1, 3, 7 and 21 days later. Five different methods for determining fT were applied and compared; 1) radioimmunoassay after ultrafiltration, 2) direct analogue based radioimmunoassay (RIA), 3) calculation from total T, sex-hormone-binding globulin (SHBG) and albumin concentrations, 4) calculation from total T, SHBG concentrations with albuminemia fixed at 40 g/L, and 5) evaluation by the (total T)/(SHBG) ratio (fT index). After AMI the total T and fT decreased rapidly (minimum at day 1) and then increased until day 21. While a lower sensitivity in detecting small changes was noted for the direct analogue based fT RIA and for the calculation using a fixed albuminemia, the evolving pattern of the 5 different fT determinations was similar despite different absolute values. However, there was a wide scattering in the results from the different methods used to determine fT. Compared to ultrafiltration, the fT values were lower by direct analogue based assay and higher by calculation. There was a trend of correlation between changes in total T and the maximum myosin concentration (r = 0.557, p = 0.02), showing a relationship between the hormonal changes and the severity of the myocardial infarction.

Adult↗