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Biomedical subjects

O Rennert

Publications and source records attributed to O Rennert.

13 recordsLinked to original sources
PubMed2005

Congenital generalized lipodystrophy: profile of the disease and gender differences in two siblings.

Congenital generalized Lipodystrophy (BSCL) or Berardinelli-Seip syndrome (Mendelian inheritance in man, catalog no. 269700) is a rare autosomal recessive syndrome characterized by paucity of body fat since birth and insulin resistance. The pathophysiology of this condition is unclear, but defects in insulin function and impaired adipogenesis have been described as important factors in the etiology of the disease. Recently, two gene loci have been identified to harbor the mutations causing this disorder: BSCL1 mapped to human chromosome 9q34 (1, 2) and BSCL2 mapped to human chromosome 11q13 (1, 3). This report describes the natural history of the disease in two siblings (female and male) of Lebanese origin who have mutations in the BSCL2 locus (669delGTATC).

Child↗
PubMed1986

Dominantly inherited craniodiaphyseal dysplasia: a new craniotubular dysplasia.

We describe a mother and her male infant affected with a craniotubular dysplasia characterized by severe craniofacial hyperostosis and sclerosis with obliteration of paranasal sinuses and foramina of the skull base. Subsequent severe bilateral hearing loss and facial diplegia with relative sparing of the optic nerves were noted. The long bones show extreme asymmetric hyperostosis and sclerosis of the diaphyses and evidence of a modelling defect in the metaphyses. The spine, ribs, clavicles, and pelvis all show some degree of sclerosis and defective modelling, but are less severely involved. According to the definition by Gorlin, this disorder would best be classified as craniodiaphyseal dysplasia. Distinguishing features in these two patients as contrasted to previously described cases include a greater degree of hyperostosis and sclerosis than that described for other patients with craniodiaphyseal dysplasia, apparent dominant transmission, and significant metaphyseal involvement.

Adult↗
PubMed1983

Effects of amino acid infusions on cell metabolism in hemodialyzed patients with uremia.

Eighteen uremic patients received i.v. infusions of a mixture of amino acids three times per week for 3 months in an effort to improve cellular amino acid imbalance and related cell bioactivities. They were a subset of 42 uremic patients stabilized by maintenance hemodialysis and were characterized by reduced cellular levels of threonine, isoleucine, methionine, and ornithine, with increased levels of aspartate, glycine, arginine, tyrosine, and phenylalanine. Protein synthesis (3H-leucine incorporation), energy level [energy charge = (ATP + 1/2 ADP)-(ATP + ADP + AMP)], and activity of the rate-limiting glycolytic enzyme pyruvate kinase were reduced in these patients compared with 32 control normal subjects. The circulating leukocyte (88 +/- 5% granulocytes) was used as a cell model. Previously, multiple regression best-subset analysis showed that a combination of the cell levels of aspartate, valine, isoleucine, ornithine, lysine, and tryptophan could "explain" 40% of the variance in protein synthesis in these patients. Similarly, a combination of the levels of aspartate, glutamic acid, glycine, ornithine, and arginine were "predictive" of the level of energy charge. We hypothesized that protein synthesis and energy level would be improved if the amino acid infusions normalized the intracellular levels of those amino acids that were predictive of the bioactivities. After 3 months of amino acid infusions, levels of the predictive intracellular amino acids were not improved, but deviated further from baseline values. Failure to detect significant improvement in the cell bioactivities is attributed to inability to correct the imbalance in the intracellular amino acid pool.

Amino Acids↗
PubMed1976

Polyamine concentrations in bone marrow aspirates of children with leukemia and other malignancies.

High-pressure liquid chromatography analysis of polyamines in bone narrow from leukemic and nonleukemic subjects demonstrated increased concentrations of putrescine, spermidine, and spermine associated with increased cellularity. The most striking abnormality was the marked elevation of putrescine. Bone marrow polyamine analysis may be an adjunct for evaluation of leukemia patients.

Bone Marrow↗
PubMed1976

Effect of polyamines and cystic fibrosis serum on glucose transport.

The effect of plasma or serum from homozygotes and heterozygotes for the cystic fibrosis (CF) gene on the active uptake of 3-0-14C-methyl-D-glucose (3-0-14C-MDG) by rat jejunal epithelium was studied. Furthermore, the role of the polyamine, spermidine, and its products of metabolic degradation on glucose transport were investigated, and a relationship to the pathogenesis of membrane dysfunction in cystic fibrosis was postulated. Glucose transport in everted rat jejunal rings was used in the study. Results were expressed as 3-0-14C-MDG concentration ratio between the intracellular (ICF) and the extracellular fluid spaces (ECF) of the jejunal rings at the end of a 60 min incubation period. The mean ratio obtained from incubations of the rat jejunal rings in medium consisting of Krebs-Ringer-bicarbonate buffer and the labeled sugar was considered as 100% uptake. When plasma or serum, with or without spermidine, was mixed with the medium in a volume ratio of 1:3, a decrease in the active uptake of 3-0-14C-MDG was observed, expressed as percent inhibition. Percent inhibition of 3-0-14C-MDG uptake obtained when the rat jejunal rings were incubated in normal plasma was compared to that obtained with plasma from cystic fibrosis genotypes. It was found that: 1) plasma from 25 homozygous children had greater inhibitory effect on glucose uptake than plasma from 26 normal children; 2) plasma from 9 heterozygous women had greater inhibitory effect than that from 6 normal women; 3) the inhibitory effect of plasma from 3 homozygous children was not influenced by dialysis; 4) the inhibitory effects of paired plasma and serum samples from 9 homozygotes were comparable; 5) spermidine added to the incubating electrolyte solution did not affect glucose transport; 6) the addition of spermidine to reaction mixtures containing normal plasma potentiated the inhibitory effect; and 7) mixing and incubation of fresh bovine serum with reaction mixtures containing plasma from homozygotes decreased the inhibitory effect. The predominant inhibitory effect of plasma or serum from homozygotes and heterozygotes for the CF gene appears to be related to a nondialyzeable molecule(s). It does not seem to reflect the presence of high plasma glucose levels in cystic fibrosis nor to be the result of competitive inhibition between sugars. It does not seem to be the result of sodium or other electrolyte differences. A similar inhibitory effect is acquired by normal plasma after the addition of spermidine. On the other hand, plasma from CF homozygotes loses its inhibitory effect after incubation with fresh bovine serum. These findings may indicate that products of metabolic degradation of spermidine are responsible for the inhibitory effect of glucose transport and suggest the possibility of a role in abnormal polyamine metabolism in the pathogenesis of cystic fibrosis.

Adult↗