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Biomedical subjects

G Rosenfeld

Publications and source records attributed to G Rosenfeld.

At least 19 recordsLinked to original sources
PubMed2000

courtless, the Drosophila UBC7 homolog, is involved in male courtship behavior and spermatogenesis.

The courtless (col) mutation disrupts early steps of courtship behavior in Drosophila males, as well as the development of their sperm. Most of the homozygous col/col males (78%) do not court at all. Only 5% perform the entire ritual and copulate, yet these matings produce no progeny. The col gene maps to polytene chromosome band 47D. It encodes two proteins that differ in their carboxy termini and are the Drosophila homologs of the yeast ubiquitin-conjugating enzyme UBC7. The col mutation is caused by an insertion of a P element into the 3' UTR of the gene, which probably disrupts translational regulatory elements. As a consequence, the homozygous mutants exhibit a six- to sevenfold increase in the level of the COL protein. The col product is essential, and deletions that remove the col gene are lethal. During embryonic development col is expressed primarily in the CNS. Our results implicate the ubiquitin-mediated system in the development and function of the nervous system and in meiosis during spermatogenesis.

Alleles↗
PubMed1994

Activation of protein kinase C by purified bovine brain 14-3-3: comparison with tyrosine hydroxylase activation.

In the course of the purification of 14-3-3 protein (14-3-3) we found that 14-3-3 isolated from bovine forebrain activates protein kinase C (PKC), rather than the previously reported protein kinase C inhibitory activity (KCIP). We have characterized the 14-3-3 activation of PKC. The physical properties of purified PKC activator are the same as those previously reported for 14-3-3 and KCIP; i.e., (1) it is composed of subunits of molecular weight 32,000, 30,000, and 29,000; (2) it is homogeneous with respect to molecular weight, as judged by native gradient-gel electrophoresis, with a molecular weight of 53,000; and (3) it is composed of at least six isoforms when analyzed by reverse-phase HPLC. The concentration dependence of PKC activation by 14-3-3 is in the same range as that shown previously for KCIP inhibition of PKC, and as that required for 14-3-3 activation of tyrosine hydroxylase; a maximal stimulation of two- to three-fold occurs at 40-100 micrograms/ml. 14-3-3's activation of PKC is sensitive to alpha-chymotrypsin digestion but is not heat labile. Activation is specific to PKC; at least two other protein kinases, cyclic AMP- and calcium/calmodulin-dependent protein kinases, are not activated. The activation of PKC by 14-3-3 is independent of phosphatidylserine and calcium and, as such, is an alternative mechanism for the activation of PKC that obviates its translocation to membranes.

14-3-3 Proteins↗
PubMed1992

14-3-3 proteins: a highly conserved, widespread family of eukaryotic proteins.

A family of proteins known as 14-3-3 is currently receiving increased attention by investigators studying a broad range of biological systems, including plants and invertebrates. The outstanding feature of this family is the extraordinarily high sequence conservation observed. Current thinking indicates that these proteins may function as regulators in signal transduction/phosphorylation mechanisms.

14-3-3 Proteins↗
PubMed1984

Computed tomographic findings in septo-optic dysplasia: discordance between clinical and radiological findings.

The clinical and radiological findings in four children with septo-optic dysplasia are reported. All four had growth retardation associated with growth hormone deficiency, as well as varying degrees of ophthalmologic dysfunction. The CT scan findings spanned a spectrum from normal to the expected abnormalities involving the ventricular system and orbits. Only two of the four had an absent septum pellucidum. A third patient had normal CT scans except for optic nerve hypoplasia, while the fourth had entirely normal CT scans of both the brain and orbits. Because the anatomic defects of septo-optic dysplasia may be subtle, an apparently normal CT scan does not invalidate the clinical diagnosis of septo-optic dysplasia.

Brain↗
PubMed1980

Intrahepatic cholestasis for 15 years without cirrhosis.

Whether prolonged cholestasis is followed by hepatic cirrhosis is still controversial. We have studied two unrelated children who have had cholestasis for 15 years, but neither of whom have developed cirrhosis. Both have severe growth retardation, peculiar facies, pulmonic stenosis, transitory renal tubular acidosis, and vitamin D-resistant rickets. The patients presented in infancy with hepatomegaly and direct hyperbilirubinemia; liver biopsy at that time revealed cholestasis and paucity of bile ducts. Subsequent serial liver biopsies have continued to demonstrate cholestasis, but there has been no evidence of cirrhosis. Electron microscopy has revealed swollen and blunted microvilli of the canalicular membrane of the hepatocyte. The patients have had elevated bile acids in the serum as well as a reversed ration of tri- to dihydroxy bile acids. Treatment with cholestyramine and phenobarbital has brought about symptomatic relief from severe pruritus and excoriation and has lowered the level of serum bile acids, although they are still above the normal range. These findings suggest that cholestasis accompanied by an elevated and reversed bile acid ratio does not universally cause hepatic cirrhosis.

Adolescent↗
PubMed1978

Experimental defibrination and bothropase: a study on the fibrinolytic mechanism in vivo.

Fibrinogen was depleted in dogs injected with a single dose of bothropase even if pretreatment followed by a continuous infusion of antifibrinolytic drugs was performed during defibrination. The activation of the fibrinolytic system as a secondary effect of the defibrination syndrome induced by bothropase injection was blocked completely by aprotinin (Trasylol) but not by EACA. Plasmin activity in spite of the inhibition of plasminogen activator suggests that, either an excess of activator is released in circulation or a plasmin-antiplasmin complex is dissociated by the circulating fibrin, according to the hypothesis of Ambrus and Markus [1], and Back et al. [4] for the mechanism of fibrinolysis in vivo. An experimental model is suggested for the study of the fibrinolytic mechanism in vivo, by the association of defibrinating agents, antivenom and antifibrinolytic drugs.

Afibrinogenemia↗