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Biomedical subjects

E Caspi

Publications and source records attributed to E Caspi.

At least 289 records · Page 16Linked to original sources
PubMed1968

The role of deoxycorticosterone in the biosynthesis of cardenolides in Digitalis lanata.

The role of deoxycorticosterone in the biosynthesis of digitoxigenin was investigated by the simultaneous administration of deoxy[1,2-(3)H(2)]corticosterone and [4-(14)C]progesterone to a Digitalis lanata plant. The biosynthetically formed [(3)H,(14)C]digitoxigenin and deoxy[(3)H,(14)C]corticosterone were isolated and the distribution of the two isotopes in these products was determined. The transformation of progesterone into deoxycorticosterone in vivo was established. The biosynthetic route from progesterone via deoxycorticosterone to cardenolides was found to be of little significance.

Carbon Isotopes↗
PubMed1967

Progesterone: its possible role in the biosynthesis of cardenolides in Digitalis lanata.

The incorporation of progestrone-7alpha-(3)H and pregnenolone-7alpha-(3)H into digitoxigenin, gitoxigenin, and digoxigenin in isolated, surviving leaves of Digitalis lanata was demonstrated. In addition, the conversion of pregnenolone to progesterone in the same system was proved. The results tend to indicate that progesterone is as good a precursor of cardenolides as pregnenolone It is suggested that the biosynthesis of cardenolides might proceed through the intermediacy of progesterone.

Chromatography, Paper↗
PubMedDate not supplied

Concerning the pathway from 19-oxoandrost-4-ene-3,17-dione to estrone.

The conversion of a molecule of 19-oxoandrost-4-ene-3,17-dione [1a] to estrone [2a] by human placental aromatase requires a molecule of oxygen and of NADPH. An atom of this molecule of oxygen is incorporated into the extruded formic acid derived from C-19 of [1a]. It was proposed that the O2 is utilized for the enzymatic 2 beta-hydroxylation of [1a] and the released intermediate 2 beta-hydroxy-19-oxoandrost-4-ene-3,17-dione [5a] aromatized nonenzymatically. Should [5a] be an obligatory intermediate of estrogen biosynthesis, then all the oxygen of its 2 beta-hydroxyl must be incorporated into the extruded formic acid. We have previously synthesized [2 beta-18O; 19-3H] [5c] and proved that none of its 2 beta-18O was incorporated in the formic acid extruded in the aromatization. On this basis we concluded that [5a] can not be an obligatory precursor of estrogen biosynthesis. The trapping of radioactive androst-4-ene-2 beta,3 beta,17 beta,19-tetrol in a reductively terminated incubation of a mixture of radioactive androst-4-ene-3,17-dione and [5a] with crude placental aromatase was interpreted as evidence in support of the intermediacy of [5a]. We confirmed that the tetrol can indeed be trapped in the reductively terminated incubations. However, considering that the crude placental enzyme preparation very likely contains numerous activated oxygen species capable of a variety of oxidation reactions, most of which may not be related to estrogen elaboration, and in view of our results quoted above, the origin and the eventual biosynthetic role of the parent compound of the tetrol remains to be determined.

Androstenedione↗
PubMedDate not supplied

Thin ribs in neonatal myotonic dystrophy.

The recently described thin ribs seen in a neonate suffering from myotonic dystrophy represents a valuable sign for early detection of this condition. Thin ribs were found on chest radiographs of two siblings a short time after birth. This led in retrospect to the diagnosis of neonatal myotonic dystrophy. The diagnosis was confirmed by clinical and electromyographic data of myotonic dystrophy in the mother who was not previously known to have the disease. Both children died at the age of 2 days from respiratory distress. All children of affected mothers should have a chest radiograph soon after birth in order to help in diagnosis and to establish the frequency of this sign.

Female↗
PubMedDate not supplied

A comparison of clomiphene/menotropins and D-Trp6-LH-RH/menotropins cycles of IVF-ET in the same patients.

Pituitary suppression by long-acting D-Trp6-LH-RH and concomitant hMG ovarian stimulation for in vitro fertilization and embryo transfer (ET) has been used in 19 patients who previously failed to conceive, following ovarian stimulation by clomiphene citrate and hMG. When available, up to five embryos were transferred. Compared with the previous CC/hMG cycles, D-Trp6-LH-RH/hMG cycles were associated with significantly more embryos (P less than .002), lower follicular-phase basal LH levels (P less than .05), and a higher early luteal progesterone level (P less than .05). Following D-Trp6-LH-RH/hMG cycles, 11 patients had a clinical pregnancy. The multiple pregnancy rate was 18% and the abortion rate, 18%. Thirty percent of the cycles (6/20) were associated with the ovarian hyperstimulation syndrome. These promising results warrant a further trial of D-Trp6-LH-RH-hMG stimulation.

Adult↗