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Biomedical subjects

M Roger

Publications and source records attributed to M Roger.

At least 199 records · Page 11Linked to original sources
PubMed1981

Falsely elevated serum thyrotropin (TSH) in newborn infants: transfer from mothers to infants of a factor interfering in the TSH radioimmunoassay.

In a TSH screening program for congenital hypothyroidism we detected seven newborn infants with normal plasma T4 and T3 levels but high immunoassayable TSH. Similar findings were obtained in their mothers. Serial plasma dilution curves, with and without the addition of normal rabbit serum to the samples, showed that the result of TSH assay performed with antihuman TSH rabbit antiserum was falsely elevated in mothers and infants by an interfering factor. Follow-up of the infants demonstrated that the falsely elevated plasma TSH levels returned to normal within the first 6 months of life. On the contrary, plasma TSH levels remained high in the mothers. These results suggested a placental transfer of maternal antibodies. Indeed, the analysis of the mothers anamnesis revealed that all had previously received injections of a microbial vaccine cultured on a rabbit lung-containing medium. We conclude that placental transfer of a maternal antirabbit factor may cause an artefactual hyperthyrotropinemia in the newborn and the incorrect diagnosis of neonatal hypothyroidism. This can be avoided by the addition of normal rabbit serum or immunoglobulin to the TSH RIA tubes.

Animals↗
PubMed1981

[Recovery of preovulatory human oocytes (author's transl)].

Rapid radio-immune assaying of LH was carried out four times daily on 52 women in the preovulatory phase of the cycle. This method enables the precise detection of the LH surge and recovery of the mature oocyte by laparoscopic aspiration of the follicular content, just before ovulation, which is between 28 and 36 hours after the start of the LH surge. The oocytes was recovered in 27 out of 41 patients with a normal cycle (66%). The rate of recovery per follicle aspirated is comparable in a natural cycle to that after treatment with Clomid (80 to 84%).

Adult↗
PubMed1981

[Serum somatomedin activity in children after surgery for craniopharyngioma (authors transl)].

Serum somatomedin activity was measured in 43 sera from 22 children aged 5 to 15 years operated on for a craniopharyngioma. All had a complete growth hormone deficiency and none received growth hormone therapy. At the time of the study, hydrocortisone therapy was given 29 times and thyroid powder 33 times. In these conditions, a highly significant correlation was found (r = 0.652, p less than 0.001) between somatomedin activity and growth velocity during the past three months. A negative correlation was also found with serum cortisol in patients who did not receive hydrocortisone (r = 0.654, P less than 0,05) and a positive correlation with serum concentrations of T4 (r = 0.640, p less than 0.05) and %3 (r = 0.956, p less than 0.001) in patients who did not receive thyroid powder. In contrast, no correlation was found with serum prolactin and insulin concentrations. These data establish than in children operated for craniopharyngioma, growth is related to a generation of somatomedin independent of growth hormone secretion, and closely controlled by endogenous secretions of cortisol and thyroid hormones.

Adolescent↗
PubMed1980

Excision and repair of mismatched base pairs in transformation of Streptococcus pneumoniae.

The use of heteroduplex DNA molecules as donors in pneumococcal transformation makes it possible to follow the fate of each DNA strand. The integration efficiency of each strand depends strongly upon the single base changes it carries. The function (hex) which reduces drastically the transformation yield of markers referred to as low efficiency (LE) tends to remove either donor strand without respect ot which one is introduced. In the case of high efficiency (HE) markers the reduction in the transformation yield involves the elimination of only one donor strand. For a given locus it can be either one depending upon the mutation. The reduction in transformation yield can be less drastic for HE markers than for both strands of the LE markers. These data are discussed in terms of differences in the affinity for mismatched base pairs. We have studied the transfer of information from each donor DNA strand to the recipient genome, on the basis of differences in the rates of phenotypic expression of a given marker introduced on opposite strands. Results show that, as in the case of LE markers, the information from HE markers, when introduced on the strand recognized by the hex function, is transmitted to both strands of the recipient molecule. Correction of the recipient strand to homozygosis probably accounts for this information transfer. These results, together with earlier investigations, strongly suggest that the hex function is an excision-repair system acting on donor-recipient base pair mismatches.

Base Sequence↗
PubMed1980

Plasma gonadotropin and testosterone values in infants with cryptorchidism.

Plasma gonadotropins and testosterone levels have been studied from day 30 +/- 6 to day 120 +/- 10 in 57 term male infants born with undescended testes-bilaterally in 22 and unilaterally in 35. Clinical follow-up of these infants showed that spontaneous testicular migration occurred at 2 to 4 months in 27 of them; the 30 others remained cryptorchid at 6 months. Plasma LH and the postnatal rise in testosterone concentration were significantly lower in patients remaining cryptorchid, either unilaterally or bilaterally, than in infants with delayed spontaneous descent of one or both testes. A significant positive correlation was found betwen plasma LH and testosterone values within these two groups of subjects. Plasma FSH levels were not different in the two groups. These data suggest a primary LH deficiency in cryptorchidism, resulting in a blunted postnatal secretion of testosterone. It may be speculated that the early postnatal deficiency of the LH-Leydig cell axis in cryptorchid patients contributes to impair both testicular migration and maturation.

Cryptorchidism↗
PubMed1980

Clinical, cytogenetical, histological, immunological and hormonal studies in a case of true hermaphroditism.

A true hermaphrodite with ambiguous genitalia and 46XX karyotype was studied from 18 months of age to 17 years. At 13 years, he developed an ambiguous puberty, with marked bilateral gynaecomastia and public hair score three. A relatively high testosterone level (21 nmol/l), not increased by hCG stimulation, was associated with a high LH level (6 UI/l). In the venous blood of the right ovotestis, the steroid concentrations were in the adult male range, especially testosterone (1400 nmol/l). After removal of the right gonad, large fluctuations of oestradiol levels were observed (150-810 pmol/l). The testosterone secretion of the left ovotestis was low, concentrations begin 4.2 and 130 nmol/l in peripheral and gonadal blood respectively at 16 years. A significant LH surge was induced by oral ethinyl-oestradiol before removal of the left gonad. The 5 alpha-reductase activity was normal in pubic skin. In the left gonad the concentrations of cytosol receptors for testosterone and 5 alpha-dihydrotestosterone (DHT) were significant: 14.5 and 65.5 fmol/mg protein respectively. However the plasma DHT level was not increased by hCG. Finally, the presence of H-Y antigen was demonstrated on lymphocytes. This accords with the presence of testicular tissue in an XX subject, and with significant testosterone production. The high testosterone production did not prevent the appearance of a positive oestrogen-LH feedback. The relative peripheral insensitivity to testosterone, is, in some ways, inconsistent with the presence of receptors for androgens.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗