Abnormalities of lipoprotein and carbohydrate metabolism in degenerative diseases of the nervous system--motor neuron disease and spinocerebellar degeneration

The levels of plasma high density lipoprotein (HDL) cholesterol and plasma triglyceride were determined in 44 patients with motor neuron disease (MND) and in 36 patients with spinocerebellar degeneration (SCD). In both groups the HDL cholesterol levels were significantly lower than those in healthy controls, whereas the plasma triglyceride levels were higher than those in the controls. Glucose levels during the oral glucose tolerance test (GTT) were significantly higher in both MND and SCD groups than in healthy controls. Immunoreactive insulin (IRI) levels during GTT were rather higher at 0 and 120 min in both MND and SCD groups than in healthy controls. Glycosylated hemoglobin levels were lower in MND than in the controls. These results indicate that both lipoprotein and carbohydrate metabolisms were impaired in MND and SCD groups. The possibility was presented that denervation might play a part in the pathogenesis of abnormalities of lipoprotein and carbohydrate metabolisms.

Renal disposition of moxalactam in experimental animals as revealed by stop-flow analysis

The mechanisms of moxalactam excretion were studied by stop-flow analysis in dogs, monkeys, and rabbits. In dogs, the amount of moxalactam excreted in the urine was almost equal to that estimated by glomerular filtration. There was no specific moxalactam peak corresponding to the p-aminohippuric acid (PAH) peak in the stop-flow patterns of the dogs. The PAH peak disappeared with administration of probenecid, but the moxalactam stop-flow pattern showed no change. In monkeys, no specific moxalactam peak corresponding to the PAH peak could be detected. In the stop-flow pattern of the rabbit, the peak moxalactam concentration corresponded with that of PAH and disappeared with probenecid. These results suggest that in dogs and monkeys renal excretion of moxalactam takes place mostly through glomerular filtration. In rabbits, however, there is a small renal tubular secretory component added to the primary element, glomerular filtration. These observations point to differences in the mechanisms of moxalactam excretion in different animal species.

Age-related differences in human skin collagen: solubility in solvent, susceptibility to pepsin digestion, and the spectrum of the solubilized polymeric collagen molecules

Age-related differences of human skin collagen in solubility, susceptibility to pepsin digestion, and the spectrum of collagen molecules were systematically examined. Less than .5% of the skin collagen were solubilized in a neutral salt solution. The solubility in acetic acid decreased rapidly during maturation and then slowly with age. Insoluble collagen from an infant was almost completely solubilized by pepsin digestion, whereas most of that from the elderly individuals remained insoluble even after four repeated times of pepsin digestion. The solubilized collagen was considered to contain a considerable amount of polymeric molecules. Characteristically, the amount of the Millipore-retained fraction of pepsin-solubilized collagen was prominent at the fourth decade. These differences represent the aging process of collagen.

Mutagenicity of 2,4-dinitrotoluene and its metabolites in Salmonella typhimurium

2,4-Dinitrotoluene (2,4-DNT) and its metabolites (2A4NT, 4A2NT, 2,4-DNB, 2A4NB, 4A2NB, 2,4-DAT, 2N4AAT, 2A4AAT, 2A4AABA and 2,4-DNBA), and 2,4-dinitrobenzaldehyde (2,4-DNA1), putative metabolite of 2,4-DNT, were tested for mutagenicity in Salmonella typhimurium strains TA98 and TA100. 2,4-DAT, 2N4AAT, 2A4AAT, 2A4AABA and 2,4-DNBA were inactive for strains TA98 and TA100. 2,4-DNT itself was only a weak mutagen. Two aminonitrotoluenes (2A4NT and 4A2NT), two aminonitrobenzyl alcohols (2A4NB and 4A2NB) and 2,4-dinitrobenzyl alcohol (2,4-DNB) were increasingly mutagenic in that order, in both strains, however, they were only weak or weak mutagens at mM concentrations. In contrast with these compounds, 2,4-DNA1 was mutagenic even at microM concentrations in both strains. These results suggest that a high mutagenicity of 2,4-DNA1 may be correlated to the carcinogenicity of 2,4-DNT.

A simple method for quantitative determination of high density lipoprotein 2- and 3-cholesterol concentrations by means of polyacrylamide gel electrophoresis

A simple and rapid electrophoretic method was developed to determine quantitatively the cholesterol concentration in two main subfractions of high density lipoprotein, HDL2 and HDL3. A polyacrylamide gel on which prestained serum was fractionated was directly subjected to densitometry for cholesterol concentration. The result, in conjunction with the HDL-cholesterol concentration simultaneously determined by the heparin-Ca2+ method, enabled us to calculate the HDL2- and HDL3-cholesterol concentrations. These values correlated well with those determined by the ultracentrifugal method. Hence, the present method was considered useful for routine clinical application and to be superior to the ultracentrifugal method in subjects with a high level of Lp(a) lipoprotein.