Distribution of Thiamine, Thiamine Phosphates, and Thiamine Metabolizing Enzymes in Neuronal and Glial Cell Enriched Fractions of Rat Brain

The distribution of thiamine, thiamine phosphoesters, and the thiamine pyrophosphate synthetizing [thiamine-pyrophosphokinase (TPKase)] as well as hydrolyzing [thiamine pyrophosphatase (TPPase) and thiamine monophosphatase (TMPase)] enzymes was determined in neuronal and glial enriched fractions prepared from rat brain. Nucleoside diphosphatases [inosine diphosphatase (IDPase) and uridine diphosphatase (UDPase)] and nucleoside monophosphatases [uridine monophosphatase (UMPase) and inosine monophosphatase (IMPase)] were also determined. Thiamine and thiamine mono- and pyrophosphate were present in neuronal enriched fractions at concentrations 2.8, 3.6, and 4.6 times higher than in glial fractions. TMPase was found only in glial enriched fractions, whereas the levels of TPKase, UMPase, IMPase, IDPase, UDPase, and TPPase were 2.0-, 2.2-, 1.3-, 2.8-, 3.7-, and 20.8-fold higher in neuronal than in glial fractions.     

Tubular structures associated with the endothelial endoplasmic reticulum in glomerular capillaries of Rhesus monkey and nephritic man

Summary Round bodies, tubular profiles and crystalline images have been studied by electron microscopy in the endothelium of seven normal young Rhesus monkeys and in the renal glomerular endothelium of two nephritic human patients. The crystalline images are most frequently formed by aggregation of round bodies, 200–240 Å in diameter. In Rhesus monkeys a variety of crystalline images are seen. On the contrary, in nephritic patients round bodies and tubular profiles are rare and less organized. In the glomerular endothelium of two normal men they were not found.The results obtained suggest that the round bodies, the tubular profiles and the crystalline images result from sectioning of a system of undulating tubules associated with the smooth endoplasmic reticulum. In nephritic patients the formation of such a tubular system could represent a change taking place within the affected cells as a pathologic response to the disease.This work was supported by U.S. Public Health Service (N.H.I.), Grant AI-04527-03-04, and by the Consiglio Nazionale delle Ricerche (C.N.R.), Contributo 115/0815/0-1365. The Authors are greatly indebted to Miss Hermina Spiele for skilful technical assistance.     

A re-evaluation of the mesangial cells of the renal glomerulus

Summary The topographical localization of the mesangial cells in renal glomeruli of rats, and their relationships with the structures at the hilus of the glomerulus were studied in this investigation. It was observed that the mesangial cells occupy a parietal position in the wall of the glomerular capillaries, and that they are anatomically continuous with the smooth muscle cells of the tunica media of the glomerular arterioles.This study was supported by a United States Public Health Service Grant AM 08628 (Institute of Arthritis and Metabolic Diseases).     

Stomatal and cuticular transpiration of beans (Phaseolus vulgaris M.) attacked by rust (Uromyces appendiculatus [Pers.] Link)

The changes of stomatal and cuticular transpiration of bean plants were investigated by graphical transpiration curves method (Slavík 1958). Bean leaves were infected by fungusUromyces appendiculatus (Pers.) Link. After the infection the intensity of stomatal transpiration had a decreasing tendency. Beginning with the sixth day after infection, the proportion of stomatal and cuticular transpirations becomes more expressive, i.e. the leaves transpire more by cuticles than by stomata. The higher share of cuticular transpiration brings extensive water relations to the diseased plants.     

Presence of telomeric and subtelomeric sequences at the fusion points of ring chromosomes indicates that the ring syndrome is caused by ring instability

In situ hybridization of a telomeric (TTA-GGG) _n sequence to metaphases from three cases of ring chromosome, involving respectively chromosomes 4, 16, and 20, showed the presence of the cognate sequences in all three rings. To investigate whether these ring chromosomes originated by telomere-telomere fusion, we determined, by in situ hybridization, whether telomere-associated sequences and/or specific distal sequences were still present in the ring chromosomes. The finding that these sequences were preserved in all the ring chromosomes strongly indicates that they originated by telomere-telomere fusion. All three subjects carrying the ring chromosomes are affected by the so-called ring syndrome, with failure to thrive, minor dysmorphic signs and no major anomalies. The r(4) patient has the ring in mosaic form with a normal cell line and has normal intelligence. The r(16) and the r(20) patients have moderate mental retardation and suffer from seizures. We conclude that the ring syndrome, even in its more severe manifestation, is caused by ring chromosome instability.     

Enhanced erythroid burst formation in mice after testosterone treatment

A single administration of testosterone propionate (TP) in ex-hypoxic polycythemic mice induces, at 24 hr after androgen, an amplification of the erythroid burst-forming unit (BFU-E or B) pool in marrow. This phenomenon is not associated with an amplification of the erythroid colony-forming unit (CFU-E or E) compartment and is followed by its depletion. In the other hand, the 36–49 hr rise of erythropoietin (Ep) levels in serum is followed by a 60-hr amplification of the E pool. It is suggested that the latter phenomenon is mediated by enhanced Ep production, whereas the early amplification of the B compartment may derive from a direct influence of TP at the stem cell level.     

Influence of sialic acid groups on the retention of glycosphingolipids in blood plasma.

The removal of several glycosphingolipids from the circulation and their disposal in different tissue and fluid compartments was studied in adult rats. 3H-labeled dihydro analogs of several glycosphingolipids were injected intravenously and radioactivity was measured in arterial blood samples at subsequent time intervals, to obtain half life values for the labeled compound in the plasma. Half life values of less than 1 min were obtained for neutral glycosphingolipids whereas the half lives of labeled gangliosides were much longer and ranged from 3.8 to 21 h. The prompt removal of labeled neutral glycosphingolipids but not of the gangliosides indicates that sialic acid groups play a significant role in the retention of glycosphingolipids in the circulation. The results suggest that neutral glycosphingolipids are rapidly exchanged with their counterparts in a large extraplasma pool and that a major portion of this exchange could occur between plasma and liver. The detection of only a minute fraction of the injected glycosphingolipids in the cerebrospinal fluid indicates that a blood-cerebrospinal fluid barrier exists for these compounds in the rat.