Biochemical medicine最新文献

In our previous research, we found that the level of the plasminogen activity in the plasma from Duchenne-type patients with progressive muscular dystrophy was higher than of the normal boys, though the level of the plasmin inhibitors was lower. Therefore, in the present study, we investigated the differences in the fractions of plasmin inhibitors.

The subjects were nine patients (the average age being 17.1 years) who had been diagnosed, by clinical and biochemical tests, as having PMD; serving as controls were normal boys (the average age being 15 years), the patients' mothers, and the mothers of the normal boys.

The plasmin inhibitors were separated from plasma using lysine-Sepharose columns according to the method of Urita et al. (6). The determination was performed based on the method of Aoyagi et al. (7) and an immunoreactive assay.

The results were as follows: (1) No significant differences were seen between patients with PMD and control subjects with respect to either α₁-antichymotrypsin, antithrombin III, and α₁-antitrypsin or α₂-macroglobulin and inter-α-trypsin inhibitors. These results suggested that the low level of plasmin inhibitors in patients was due to the low activity of the C₁ inactivator. (2) The patients with PMD showed lower values than the normal boys in the levels of C₁ inactivator in plasma; similarly, the mothers of these patients showed lower values than the normal mothers.

The acid proteinases, neutral proteinases, protein, RNA, and DNA were estimated along with the ammonia content in muscle in rats subjected to experimental hyperammonemic states (acute and chronic) by the administration of ammonium acetate intraperitoneally. It was observed that there was a decrease in the activities of acid proteinases and neutral proteinases in muscle in acute as well as in chronic hyperammonemic states. A rise in protein content was observed in muscle under these conditions. No changes were seen in the DNA content while RNA showed a slight increase in muscle. These results were discussed with reference to the possible role of ammonia in lysosomal protein degradation as well as to its probable effect on protein synthesis through its action on transcription.

The specific activity of NAD- and NADP-linked isocitrate dehydrogenase and their regulation by thyroxine in the brain and liver of female rats of various ages were studied with the ultimate goal of better understanding the decreased physiological functioning of the brain and liver during old age. Both thyroidectomy and thyroxine treatment have differential age-dependent effects on the activities of these enzymes in both tissues. The activity of NAD-ICDH decreases whereas both cytoplasmic and mitochondrial NADP-ICDH increase simultaneously following thyroidectomy. Thyroxine administration induces NAD-ICDH and depresses NADP-ICDH. The degree of induction and/or repression is lowest in old rats. These effects of thyroxine are actinomycin D sensitive in both the tissues of rats.

Growth of brewer's yeast in the presence of Cr³⁻ led to increased yields of substances with GTF activity in assays performed with isolated adipocytes. The formation of these substances may be a means of diminishing the toxic effects of Cr on yeast. During fractionation of extracts of brewer's yeast the Cr was easily dissociated from any complexes that may have been present. The GTF activity for both yeast and adipocytes was isolated in cationic and anionic small amino-acid or peptide-like molecules. These substances caused increased glycolysis in yeast and increased glycolysis and fatty acid synthesis in adipocytes. No evidence was found that GTF aided the binding of insulin to its receptor. The GTF activity could only be demonstrated with adipocytes from rats fed a torula yeast—high sucrose diet, which may have caused the rats to have a decreased sensitivity to insulin.

The elevated phenylalanine concentration in the blood of untreated phenylketonuric children is known to be paralleled by decreased concentrations of other amino acids in the blood and brain tissue. Due to the low availability of other large, neutral amino acids in the brain, protein synthesis in, and the normal development of, the brain are disturbed. A similar effect is observed in suckling rats rendered hyperphenylalaninemic by the daily injection of phenylalanine plus α-methylphenylalanine, an in vivo inhibitor of the phenylalanine-hydroxylating pathway in the liver. In this study, the simultaneous injection of lysine is shown to prevent the depletion of amino acids from the blood and brain tissue, and the retardation of brain growth, in suckling hyperphenylalaninemic rats. It is suggested that both amino acids, phenylalanine and lysine, are important rate-limiting substrates for the rapid protein anabolism of developing tissues. In the presence of an excess of phenylalanine, other amino acids, and in relation to its requirement during the phase of hyperplastic growth in particular lysine, are less available from the circulation and limit phenylalanine-stimulated protein synthesis in developing tissues. The supplementation of lysine to developing hyperphenylalaninemic rats prevents the consequences of this effect, i.e., the depletion of amino acids in the blood, and therefore, in the brain tissue, and the retardation of brain growth.

An ion-pairing high performance liquid chromatography method is described for the separation and quantitation of malondialdehyde in plasma. The MDA is determined as the thiobarbiturate chromogen formed by reaction of the plasma with 2-thiobarbituric acid under acid and heating conditions. However, under these conditions other interfering chromogens can also be formed. Using DEAE-cellulose chromatography followed by ion-pairing HPLC, we have been able to separate and quantitate the levels of MDA-TBA chromogen formed in plasma from other interfering chromogens. Measurements of MDA levels in the plasma of six normal individuals by HPLC gives a mean value of 4.57 ± 0.33 nmole/ml, whereas the spectrophotometric determined value is 8.83 ± 1.15 nmole/ml. These data suggest that some reevaluation of the numerous papers published on MDA levels in plasma using spectrophotometric methods may be necessary.

Human liver arylsulfatase A was resolved into six fractions by narrow pH range preparative isoelectric focusing. Analytical isoelectric focusing revealed that most enzyme fractions were composed of two adjacent charge isomers. Nevertheless, there was considerable enrichment of charge species which allowed a comparative study of selected properties. Except for the most cationic fraction, neuraminidase treatment converted enzyme in all fractions to the three most cationic species. The most electronegative enzyme species had the highest molecular mass being made up of 64-kDa subunits. As electronegativity decreased, there was concomitant decrease in molecular mass and increase in complexity of subunit composition. Two subunits—61 and 55 kDa—prevailed with increasing proportions of the smaller unit with loss of electronegativity. There was also an increasing amount of a 26-kDa fraction which became a substantial component of the most cationic subfraction. Only enzyme in the two fractions containing the largest and most anionic species were taken up by cultured fibroblasts at higher efficiency than unfractionated enzyme. It is suggested that processing or maturation of arylsulfatase A incurs stepwise removal of charge groups and/or peptide segments leading to smaller, less-charged enzyme species.

Numerous investigations have been made on the biochemistry of mammalian colostrum and milk, and previous studies have documented the presence of proteinase inhibitors in human and bovine milk (1–4). Collagenase inhibitors, however, have not yet been described in human breast milk. This preliminary report documents the presence of collagenase inhibitory activity in a fraction of human breast milk (molecular weight of 72,000 or less) collected 7 weeks postpartum.

Adjuvant arthritis was induced in rats by the injection of Mycobacterium tuberculosis, and its severity was scored according to the macroscopic findings of the legs, tail, and ears. The average score so obtained was lower in SOD-injected rats than in the control group. The depression of albumin/globulin ratio was inhibited significantly in rats treated with 10.0 mg/kg of SOD. The levels of acid phosphatase and β-glucuronidase were elevated after the administration of an adjuvant, and these lysosomal enzymes showed a remarkable increase in the control rats, while the elevation was inhibited in rats injected with 10.0 mg/kg of SOD. The levels of TBA-reactive substance in the sera and synovia were elevated at 2 weeks after the injection of adjuvant and decreased thereafter. In rats injected with 5.0 mg/kg or 10.0 mg/kg of SOD, the increase in both serum and synovial levels of TBA reactants was inhibited significantly.

These observations suggest that the aggravation of adjuvant arthritis may be associated with lipid peroxidation due to superoxide, and that SOD may be beneficial for the treatment of arthritis.

Wolman's disease is a genetic disease in which deficiency of an acid lipase results in the accumulation of cholesteryl esters, and in some tissues, of triacylglycerols (1,2). Other, uncommon lipid esters have been found in a few cases of Wolman's disease. Glyceryl ether lipids were identified in a single case of Wolman's disease (3). 7α- and 7β-hydroxycholesteryl esters, 7-ketocholesteryl esters, 5,6α- and 5,6β-epoxycholesteryl esters were found in the livers, adrenals, and spleens of two unrelated patients (4). This is the first report of the accumulation of both glyceryl ether lipids and oxygenated cholesteryl esters in Wolman's disease. The patient, a new case, was a sibling of the case we presented earlier (3,5).