Effects of aging on hydroxyproline in human heart muscle

Hydroxyproline concentration in the NaCl-soluble, TCA-soluble, and residual fractions of heart muscle was chemically determined in 40 autopsy subjects (25 men and 15 women), to study the effects of aging. In the left ventricle, the total hydroxyproline content of the endocardium and papillary muscle increased significantly in relation to age; the increase was greatest in the TCA-soluble fraction, followed by the residual fraction. Statistical analysis revealed that hydroxyproline in the residual fraction increased from the epicardium to the endocardium and then to the papillary muscle. Significant negative correlations were found between heart weight and total hydroxyproline in the epicardium and endocardium. In the right ventricle, a significant negative correlation was noted between heart weight and total hydroxyproline content. Though no correlations were evident between age and hydroxyproline content in females, significant correlations were observed between age and the total hydroxyproline content of the endocardium and papillary muscle in males. Furthermore, soluble collagen increased in most parts of the heart in females, but insoluble collagen increased in all parts of the heart in males. It is concluded that the hydroxyproline content of heart muscle increases in proportion to age and is in inverse proportion to heart weight. The increase occurs in the TCA-soluble and residual fractions, and extends from the endocardium to the papillary muscle. More profound changes in collagen metabolism are observed in males.

2,3-Bisphosphoglycerate in developing rabbit erythroid cells

Rabbits were made anemic to different extents by phenylhydrazine injections so as to vary the developmental stages of the erythroid cells in their peripheral blood and bone marrow. It was found that the more severe the anemia, the lower the concentration of glycerate-2,3-P2 in the bone marrow cells and in the circulating erythroid cells. The glycerate-2,3-P2 level was shown to rise during erythroid differentiation in a linear relationship to the hemoglobin level, corresponding to the equation Y = 0.03x + 0.29, where y is the concentration of glycerate-2,3-P2 (micromoles per ml packed cells) and x is the concentration of hemoglobin (milligrams per packed cells). The bone marrow cells were fractionated on a size (i.e. maturity) basis and enzyme activities in the fractionated cells were measured. The accumulation of glycerate-2,3-P2 was found to be primarily attributable to the increase in glycerate-2,3-P2 synthase activity. Glycerate-2,3-P2 phosphatase and phosphofructokinase increased as the cells matured from the polychromatic stages to become reticulocytes while pyruvate kinase and phosphoglyceromutase decreased. The changes in phosphofructokinase and pyruvate kinase appear to be advantageous for glycerate-2,3-P2 accumulation. The two enzyme activities directly responsible for the synthesis and the breakdown of glycerate-2,3-P2 are probably manifested by a single protein, glycerate-2,3-P2 synthase-phosphatase.

Terminal deoxynucleotidyl transferase activity and B cell markers in chronic myelogenous leukemia blast crisis

High terminal deoxynucleotidyl transferase activities were found in blast cells having B cell markers in 3 patients suffering from chronic myelogenous leukemia. The blast cells from these patients were lymphoblastic in appearance. Two of these cases were treated with vincristine and prednisolone. They responded well to this therapy.

Essential arginyl residues in yeast phosphoglyceromutase

Inactivation of yeast phosphoglyceromutase (tetramer) with 1,2-cyclohexanedione correlates with the modification of six arginyl residues per mole of the enzyme. Protection experiments using 3-phosphoglycerate suggest that four arginyl residues (one residue per subunit) are involved in the binding of the substrate to the enzyme. The modified enzyme reversibly regained its activity upon incubation with hydroxylamine. The reactivity of lysyl residues which have been shown to be involved in the active site is markedly reduced in the enzyme inactivated with 1,2-cyclohexanedione, indicating that the lysyl and arginyl residues are in close proximity in the active site.

[The tentorial meningioma fed by "marginal tentorial artery" arising from the external carotid artery--a case report and review of literature (author's transl)]

It is well known that a Bernasconi-Cassinari artery is an important finding at diagnosis of the abnormality in tentorium. Since Bernasconi and Cassinari reported the artery in 1956, many reports have been presented and showed that the artery arose from the intracavernous portion of the internal carotid artery. We presented a 54-year-old female with tentorial meningioma. In selective external carotid angiography, the artery feeding the tumor was revealed arising from the accessory meningeal artery, which came off the internal maxillary artery and passed into the carnium through the foramen ovale, and took the same course of "Bernasconi-Cassinari artery". This angiographic finding suggests that it is possible for marginal tentorial artery to arise from an external carotid arterial system. It is said in the anatomical studies, when the trunk of primitive maxillary artery which is one of maxillo-carotid anastomotic arteries in fetus regresses, "marginal tentorial artery" usually remains linked to the internal carotid artery. But, if this transition of "the artery" from the external to the internal carotid artery failed, it is easily conceived the artery results in the origin of accessory meningeal artery, a branch of the external carotid artery.

Subunit structure and multifunctional properties of yeast phosphoglyceromutase

1. A new and efficient method for preparation of pure phosphoglyceromutase from baker's yeast (Saccharomyces cerevisiae) is described. Proteolytic alterations of the enzyme during extraction can be minimized by grinding the dried yeast with aluminium oxide at low temperature. 2. Yeast phosphoglyceromutase contains four highly similar, probably idential subunits of molecular weight 28000, a conclusion based on the following observations. Polyacrylamide gel electrophoresis containing dodecylsulphate or urea gives a single band, indicating that the enzyme is composed of four subunits similar in their molecular weight and net charge. Cyanogen bromide cleavage and tryptic digestion of the enzyme yield the number of peptides expected for identical subunites from the amino acid composition analysis. 3. The purified phosphoglyceromutase preparation has bisphosphoglyceromutase activity synthesizing 2,3-bisphosphoglycerate from 1,3-bisphosphoglycerate and 3-phosphoglycerate. It has been reported that yeast phosphoglyceromutase catalyzes the hydrolysis of 2,3-bisphosphoglycerate at the same active site which catalyzes the phosphoglyceromutase reaction [Sasaki, R. et al (1971) Biochim. Biophys, Acta, 227, 584-594, 595-607]. Immunological studies and chemical modification experiments indicate that bisphosphoglyceromutase activity also is due to the phosphoglyceromutase protein and involves amino groups which have been shown to be essential for the other two activities.

Multifunctional enzyme, bisphosphoglyceromutase/2,3-bisphosphoglycerate phosphatase/phosphoglyceromutase, from human erythrocytes. Evidence for a common active site

Bisphosphoglyceromutase and 2,3-bisphosphoglycerate phosphatase activities responsible for 2,3-bisphosphoglycerate metabolsim in human red cells are displayed by the same enzyme protein which has phosphoglyceromutase activity [Sasaki, R., et al. (1975) Eur J. Biochem. 50, 581-593]. This enzyme was subjected to chemical modification by trinitrobenzenesulfonate. The three enzyme activities were inactivated by trinitrobenzenesulfonate at the same rate. The sulfhydryl content of the enzyme was unchanged during trinitrophenylation, indicating that derivatization was through the amino group. Trinitrophenylation of about one amino group per mole of the enzyme resulted in complete loss of the three activities. Both 2,3-bisphosphoglycerate and 1,3-bisphosphoglycerate inhibited trinitrophenylation and effectively protected the enzyme from inactivation. Although monophosphoglycerates did not show any protective effect at concentrations which should be adequate based upon their kinetic constants, they were protective at higher concentrations. Inactivation by trinitrophenylation was an apparent first-order reaction. The dissociation constant of the enzyme - 2,3-bisphosphoglycerate complex was determined by analyzing the first-order reaction on the assumption that the protective effect of 2,3-bisphosphoglycerate was due to competition with trinitrobenzenesulfonate. The dissociation constant was in good agreement with kinetic constants of 2,3-bisphosphoglycerate in the enzyme reactions, which indicated that 2,3-bisphosphoglycerate did indeed exert its protective effect through competition with trinitrobenzenesulfonate for an amino group of the enzyme. The protective effect of monophosphoglycerates could be rationalized with kinetic evidence that 2-phosphoglycerate at high concentrations interacts with the 2,3-bisphosphoglycerate binding site. These results indicate that the enzyme exhibits the three enzyme activities at a common active site at which one amino group essential for binding of bisphosphoglycerates is located. Based on the multifunctional properties of this enzyme, a possible mechanism was discussed for regulation of 2,3-bisphosphoglycerate metabolism in human red cells.

Premature induction of amylase in pancreas and parotid gland of growing rats by dexamethasone

Studies were made on changes in the contents of alpha-amylase (EC 3.2.1.1) in the pancreas and parotid gland of rats during postnatal development, on the premature induction of this enzyme by hormones and on the existence of specific glucocorticoid receptors in these tissues. The amylase content in the pancreas increased from the 9th day after birth and reached the adult level on the 28th day, its content in the parotid gland increased rapidly from the 16th to the 28th day after birth and then rose more gradually to the adult level. Injection of dexamethasone into rats 6--8 days after birth induced increase in the amylase of the pancreas but not the parotid gland. However, injection of dexamethasone into weanling rats 21--23 days after birth resulted in precocious induction of amylase in both tissues. Specific glucocorticoid receptors were detectable in the parotid gland of rats from 6 days after birth but were almost undetectable in the pancreas until adolescence.