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Biomedical subjects

R Wolter

Publications and source records attributed to R Wolter.

61 records · Page 4Linked to original sources

Molecular characterisation of GTP1, a Saccharomyces cerevisiae gene encoding a small GTP-binding protein.

DNA sequence analysis upstream of the yeast DNA repair gene SNM1 revealed gene GTP1 with an ORF of 573 bp on chromosome XIII. The putative amino-acid sequence of the encoded protein shows homology to proteins of the ARF-class of small GTP-binding proteins. Homology within GTP-binding motifs is highly conserved. Gene disruption showed that GTP1 is not an essential gene and that it has no influence on the expression of the DNA repair gene SNM1 with which it shares a 191-bp promoter region.

ADP-Ribosylation Factors↗

Partial 17, 20-desmolase and 17 alpha-hydroxylase deficiencies in a 16-year-old boy.

Thirteen plasma steroids as well as ACTH, LH and FSH were measured by specific RIAs under basal and dynamic conditions in a 16-year-old boy (normal external genitalia, 46, XY karyotype) who presented slowness and unachievement of pubertal development. On the delta 4-pathway: basal levels of testosterone and dihydrotestosterone were low- with a normal ratio-, delta 4-androstenedione and 11 beta-hydroxyandrostenedione were in the low normal range. Meanwhile, 17 alpha-hydroxyprogesterone and progesterone levels were markedly elevated. On the delta 5-pathway: dehydroepiandrosterone was extremely low while 17 alpha-hydroxypregnenolone and pregnenolone were almost normal; dehydroepiandrosterone sulfate was subnormal while pregnenolone sulfate was normal. Cortisol, aldosterone were normal while ACTH was moderately increased. Basal and responsive levels of LH and FSH were markedly increased. ACTH stimulation induced a subnormal rise of cortisol and 11 beta-hydroxyandrostenedione, a low or absent rise of dehydroepiandrosterone, 17 alpha-hydroxypregnenolone, androstenedione and 17 alpha-hydroxyprogesterone contrasting with a marked rise of pregnenolone and progesterone. After hCG stimulation, responses were low for testosterone, extremely high for 17 alpha-hydroxyprogesterone with a normalisation of the 17 alpha-hydroxyprogesterone/progesterone ratio. Fluoxymesterone dramatically reduced the pathologically high basal levels of progesterone and 17 alpha hydroxyprogesterone. Dexamethasone induced only a minute decrease in the delta 4-progestagens, a marked decrease in pregnenolone, with a more than 80% reduction of 17 alpha- hydroxypregnenolone, dehydroepiandrosterone, dehydroepiandrosterone sulfate and androstenedione. These data suggest a defect involving the cytochrome P450 common to both 17 alpha-hydroxylase and 17, 20-desmolase activities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Prolactin secretion in anorexia nervosa.

Twenty-nine anorectic female patients were subdivided in three groups: group I when primary amenorrhoea; group II when secondary amenorrhoea together with a weight (for their height) equal or above the 10th percentile of the ratio of total water over body weight (TW/B Wt); group III when secondary amenorrhoea was associated with a weight below this 10th percentile. Despite very low mean oestradiol levels (respectively 22, 36 and 32 pg/ml), prolactin secretion remained normal both in basal conditions as well as after 200 micrograms TRH iv. For group III patients, a delay in the peak prolactin response to TRH was observed but it was not statistically significant.

Adolescent↗