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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 37 records · Page 2Linked to original sources
PubMed1979

Effect of calcitonin on Ca-ATPase activity of plasma membrane in liver of rats.

The effect of calcitonin (CT) on Ca-ATPase activity in the plasma membrane fraction of rat liver was investigated. CT (80 MRC mU/100 g BW) administered subcutaneously to rats, caused a significant decrease in serum calcium, while increasing liver calcium. The administration of CT produced a rapid decrease of Ca-ATPase activity in the plasma membrane fraction of liver, whereas CT did not cause a significant alteration of p-nitrophenyl phosphatase activity. The maximal response of CT was obtained with 80 MRC mU/100 g BW. Meanwhile, the administration of imidazole (30 mg/100 g BW) which has a hypocalcemic effect, like CT, produced a significant increase in liver calcium and a corresponding fall in Ca-ATPase activity of the plasma membrane fraction. The reduction of Ca-ATPase activity produced by imidazole was significantly potentiated by the simultaneous administration of CT, and the rise in liver calcium was enhanced slightly. The present results suggest that the action of CT on liver calcium involves the decrease of Ca-ATPase activity in the plasma membrane of rat liver.

Animals↗
PubMed1979

The effect of phenoxybenzamine on the pulmonary vascular bed in surgically corrected ventricular septal defect associated with pulmonary hypertension.

From 1971 to 1977, a total of 43 cases with ventricular septal defect associated with pulmonary hypertension (VSD + PH), ranging from 3 months to 6 years of age, underwent VSD closure using cardiopulmonary bypass with a prophylactic dose of phenoxybenzamine (POB) 1 mg/Kg. Twenty of these cases are included in the present study of the effect of POB on pulmonary hypertension. The ratios of pulmonary to systemic arterial pressures (Pp/Ps) and vascular resistances (Rp/Rs) were measured before, immediately after and 1 month after VSD closure. In all cases, the Pp/Ps before VSD closure was larger than 0.75. Both Pp/Ps and Rp/Rs markedly decreased immediately after VSD closure but rose again 1 month thereafter. These results suggest the possibility of pulmonary vasodilating effect of POB, which could be potentially useful in relieving the right ventricular load in the early postoperative period. The over all mortality was 3 out of 43 cases including 2 late deaths.

Blood Pressure↗
PubMed1979

Comparative studies on actins from various sources. Fragments of actins from Ascaris muscle cleaved at cysteinyl residues in comparison with those of other actins.

Pure actins were obtained from various animal muscles: Vertebrata (skeletal, smooth, and cardiac muscles), Prochordata (smooth muscle), Nematoda (obliquely striated muscle), and Mollusca (striated, smooth and obliquely striated muscles). These actins were all identical in apparent molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. All actins treated with 2-nitro-5-thiocyanobenzoic acid yielded four major (about 33,000, 26,000, 24,000, and less than 10,000 daltons) and three minor (22,000, 17,000, and 10,000 daltons) bands in addition to intact actin on gel electrophoresis. The results suggest that all actins from various types of muscle have cysteinyl residues at similar positions on the primary structure.

Actins↗
PubMed1979

Lung pathology in infants with severe pulmonary hypertension and cardiac disease.

Lung biopsy specimens were taken from 39 infants younger than 12 months of age with congenital heart disease and severe pulmonary hypertension (Pp/Ps greater than or equal to 0.75) accompanied by respiratory distress. The pathological change in lung specimens and clinical courses were compared. These 39 infants underwent surgical treatment of patent ductus arteriosus (PDA), seven patients; ventricular septal defect (VSD), 13 patients; and complex heart anomaly, 19 patients. The common pathological findings of the lung specimens taken from these infants were lymphoid cellular infiltration and thickening of the alveolar septum, which we have called "septitis" in the present study. In most cases pulmonary vascular obstructive change was within Grade 2 of the Health-Edwards criteria. Septitis was classified into three categories: mild, moderate, and severe. Only three of the 19 infants with severe septitis survived postoperatively, whereas 10 of the 12 infants with moderate septitis and all eight with mild septitis could be successfully weaned. The cause of septitis remains unidentified. We have found the patient's age and pulmonary hypertension to be closely related to the grade of septitis in this study. Septitis plays a much more important role than pulmonary vascular obstructive change in the prognosis of pulmonary hypertensive heart disease in early infancy.

Biopsy↗
PubMed1979

[Influence of storing conditions on the amino acid concentration in human serum (author's transl)].

Whole blood, serum and deproteinized serum were stored at room temperature up to 24 h and at - 30 degrees C up to one month. The amino acid content was then determined with an automatic amino acid analyser. When whole blood is left at room temperature the concentration of citrulline, alpha-aminobutyric acid, cysteine and tryptophan remains unchanged, whereas the other amino acids show a remarkable increase or decrease. In serum stored for 24 h at room temperature, only the concentrations of aspartic and glutamic acid, serine, cysteine and phenylalanine were altered. With the exception of aspartic and glutamic acid it was possible to leave deproteinized serum up to 24 h at room temperature and up to one month at - 30 degrees C without observing a change in the concentration of the other amino acids. No change occurred, when serum was stored at - 30 degrees C for 24 h.

Amino Acids↗
PubMed1978

Characterization of NADH-cytochrome c reductase, a component of benzoate 1,2-dioxygenase system from Pseudomonas arvilla c-1.

NADH-cytochrome c reductase, a component of benzoate 1,2-dioxygenase system, was purified to homogeneity, as judged by sodium dodecyl sulfate disc gel electrophoresis and ultracentrifugation, from benzoate-induced cells of Pseudomonas arvilla. The molecular weight of the enzyme was determined to be 38,300 by sedimentation equilibrium analysis, 37,000 by Sephadex G-100 gel filtration, and 37,500 by sodium dodecyl sulfate disc gel electrophoresis, respectively, indicating that the enzyme consisted of a single polypeptide chain. The sedimentation coefficient was calculated to be 3.3 S. The Stokes radius for the enzyme was calculated to be 27 A. The isoelectric point of the enzyme was estimated to be pH 4.2. The enzyme contained 1 mol of FAD, 2 mol of iron, and 2 mol of labile sulfide/mol of enzyme. It exhibited absorption spectrum with maxima at 273, 340, 402, and 467 nm. Amino acid analysis of the enzyme revealed that it was devoid of tryptophan. The enzyme contained 9 mol of cysteine/mol of enzyme but no disulfide linkage. The turnover number of the enzyme for the NADH-dependent reduction of cytochrome c was 17,100 at 24 degrees C. Although NADPH also acted as an electron donor, NADH was highly superior to NADPH. Ferricyanide and 2,6-dichlorophenolindophenol served as electron acceptors. Certain other properties of the enzyme are also presented.

Amino Acids↗
PubMed1978

Source and hormone-dependence of Gix-gp70 in mouse serum.

The gp70 family of glycoproteins is distinguished by the role of these molecules as constituents of C-type viral envelopes and also as Mendelian cellular constituents expressed independently of virus production. The source of G(IX)-gp70 in the serum of 129 strain mice, which are not overt producers of virus, could not be traced to any organ or tissue that is known to be G(IX)-positive by serological tests. Hematopoietic tissues were excluded as source of serum G(IX)-gp70 by tests with reciprocal radiation chimeras made from 129 and 129-G(IX)(-) donors and recipients. Thymus and spleen were excluded because excision of these organs did not affect levels of G(IX)-gp70 in the serum. The serum of young adult 129 males contains roughly four times as much G(IX)-gp70 as adult 129 females and the levels rise in both sexes with increasing age. Castration of 129 males reduced the level of serum G(IX)-gp70 to that of females, and the level was fully restored by testosterone. Thus the epididymis and seminal fluid, though rich in G(IX)-gp70, do not contribute significant amounts of G(IX)-gp70 to the serum. The level of G(IX)-gp70 in the serum of testosterone-treated females, though more than double that of untreated females, did not reach the level of normal males, under the conditions tested. This may signify that G(IX)-gp70 production by males is subject to imprinting by testosterone in early life. Evidently the main source of serum G(IX)-gp70 is a tissue or organ that is common to males and females, is directly or indirectly responsive to testosterone, and has not so far been identified serologically as G(IX)- positive.

Animals↗
PubMed1978

Filamin-actin interaction. Dissociation of binding from gelation by Ca2+-activated proteolysis.

Chicken gizzard filamin has been digested with purified Ca2+-activated protease. The subunits of (Mr = 250,000) of the protein are cleaved asymmetrically into two fragments, heavy merofilamin, Mr = 240,000, and light merofilamin, Mr = 9,500. Digestion is complete at substrate to enzyme ratios of 100:1 and requires Ca2+ concentrations in excess of 0.3 mM. Heavy merofilamin binds to F-actin as evidenced by cosedimentation with F-actin, by direct observation under the electron microscope, and by its ability to inhibit actin activation of heavy meromyosin ATPase. Heavy merofilamin does not form a gel when mixed with actin, except at very low concentrations of KCl. Thus, actin binding and gelation are separable activities of filamin. We speculate that Ca2+-stimulated proteolysis may play a role in the regulation of actin-filamin interactions.

Actins↗