Biomedical subjects

E Stransky

Publications and source records attributed to E Stransky.

11 recordsLinked to original sources

PubMed1999

LeProT1, a transporter for proline, glycine betaine, and gamma-amino butyric acid in tomato pollen.

During maturation, pollen undergoes a period of dehydration accompanied by the accumulation of compatible solutes. Solute import across the pollen plasma membrane, which occurs via proteinaceous transporters, is required to support pollen development and also for subsequent germination and pollen tube growth. Analysis of the free amino acid composition of various tissues in tomato revealed that the proline content in flowers was 60 times higher than in any other organ analyzed. Within the floral organs, proline was confined predominantly to pollen, where it represented >70% of total free amino acids. Uptake experiments demonstrated that mature as well as germinated pollen rapidly take up proline. To identify proline transporters in tomato pollen, we isolated genes homologous to Arabidopsis proline transporters. LeProT1 was specifically expressed both in mature and germinating pollen, as demonstrated by RNA in situ hybridization. Expression in a yeast mutant demonstrated that LeProT1 transports proline and gamma-amino butyric acid with low affinity and glycine betaine with high affinity. Direct uptake and competition studies demonstrate that LeProT1 constitutes a general transporter for compatible solutes.

Amino Acid Sequence↗

PubMed1984

[Effect of intranasal administration of an LH-RH analog on basal gonadotropin concentrations and stimulation in patients with hypogonadotropic hypogonadism].

The effect of intranasal administration of the LHRH analogue D-Leu-6-des Gly-10 NH2EA on gonadotropin (Gn) stimulation was studied in 8 juvenile patients with ascertained hypogonadotropic hypogonadism, due to multiple pituitary deficiencies (MPD) in 5 cases and the Prader-Willi syndrome (PWS) in the remaining 3 patients. A bolus LHRH test was performed before and after a treatment period lasting between 2 and 5 weeks. In 2 MPD patients there was a transient rise in basal LH concentrations and a slight improvement in the second LHRH test; hence a hypothalamic lesion is assumed. In the other MPD patients there was no change in Gn stimulation. The sex steroid levels remained low. Gn stimulation was improved in all 3 patients with PWS after LHRH administration and in one 19-year-old boy the onset of puberty was probably induced by this therapy. However, after continuous administration of the analogue the initially increased Gn levels decreased again. In view of this inhibiting action on Gn levels the LHRH analogue does not appear suitable for the long-term treatment of hypogonadotropic hypogonadism.

Administration, Intranasal↗

PubMed1983

[The L-DOPA-propranolol test for the evaluation of reserves in secretory growth hormone].

The growth hormone (GH) reserve of 75 short probands (age 1.9 to 23.8 years) was evaluated on the basis of oral L-dopa (300 mg/m2) and propranolol (0.75 mg/kg) administration. The GH response was normal in 21 probands (20.9 +/- 1.24 ng/ml; means +/- SEM) and was found to be higher than the response to the insulin or arginine test. 39 patients failed to respond (less than 6 ng/ml) and were diagnosed as GH deficient. In 15 cases an "intermediate" response (greater than 6 less than 12 ng/ml) was found and in these patients partial GH deficiency was assumed. There was not a single false positive result with this test, which cannot be said for any of the other commonly-used stimulation tests. In two children hypoglycaemic blood glucose levels were observed during the test, whilst in one case loss of consciousness and convulsions were seen. In four patients the test had to be interrupted because of side effects. These children had the following findings in common: GH deficiency was confirmed and the patients were still very young and basal blood glucose levels were relatively low at the beginning of the test. The L-dopa-propranolol test is an effective and reliable GH stimulation test, but severe side effects may occur.

Adolescent↗

PubMed1968