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Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 919 records · Page 51Linked to original sources
PubMed1981

Hormone-sensitive lipase in differentiated 3T3-L1 cells and its activation by cyclic AMP-dependent protein kinase.

Differentiation of 3T3-L1 fibroblasts to adipocyte-like cells was accompanied by a 19-fold increase in neutral triglyceride lipase activity, a 12-fold increase in diglyceride lipase activity, a 10-fold increase in monoglyceride lipase activity, and a 280-fold increase in cholesterol esterase activity. In contrast, acid acylhydrolase activities did not increase during differentiation. The rate of glycerol release from unstimulated intact cells increased by more than 1 order of magnitude upon differentiation. Isoproterenol (1 microM) and 1-methyl-3-isobutylxanthine (0.1 mM) further stimulated this rate of glycerol release 3-fold. The neutral triglyceride lipase activity in cell-free preparations of differentiated cells was activated 105% by cyclic AMP-dependent protein kinase. Neutral cholesterol esterase, diglyceride lipase, and monoglyceride lipase were also activated (117%, 10%, and 37+, respectively) by cyclic AMP-dependent protein kinase. In contrast, protein kinase had no effect on any of the four lysosomal acid acylhydrolase activities. Thus, hormone-sensitive lipase, the most characteristic and functionally important enzyme of adipose tissue, has been characterized in differentiated 3T3-L1 cells. The 3T3-L1 cell should be a valuable model system in which to study regulation of hormone-sensitive lipase, particularly its long-term regulation.

Adipose Tissue↗
PubMed1981

Effects of vagotomy and gastrectomy on pancreatic glucagon release.

The effects of gastrectomy and vagotomy on pancreatic glucagon release were investigated clinically. The study included 20 men and eight women, who ranged in age from 28 to 69 years, and who were divided into the following four groups: 1) patients with gastroduodenal ulcers treated with partial gastrectomy, by the Billroth I method, whose hepatic branch was preserved (n = 7). 2) Patients with gastroduodenal ulcers treated with partial gastrectomy, by the Billroth II method, whose hepatic branch was preserved (n = 7). 3) Patients with gastric carcinoma treated with subtotal gastrectomy, by the Billroth I method. In these cases lymphadenectomy required section of the hepatic branch (n = 7). 4) Patients with gastric carcinoma treated with subtotal gastrectomy, by the Billroth II method. In these cases lymphadenectomy required section of the hepatic branch (n = 7). Oral glucose tolerance tests were performed in 10 patients, before operation, and in 28 gastrectomized and vagotomized patients. In the preoperative patients and in the first group, oral glucose (50g) suppressed pancreatic glucagon release, but in the other groups pancreatic glucagon levels were markedly increased.

Adult↗
PubMed1981

A new method of blood galactose estimation for mass screening of galactosemia.

A new method for quantitative determination of galactose in blood by fluorescence of NADH was described. The assay system consisted of beta-galactose dehydrogenase, NAD, buffer and a denatured blood disc (3 mm diameter), and the reaction was carried out for 1 hr at 37 degrees C. Denaturation of hemoglobin was accomplished by exposing the blood disc to a vapor of formic acid in an air-tight container; this procedure completely eliminated false positive cases of galactosemia. This method can be applied in a wide range of galactose concentration from low (0 mg%) to high levels (200-1,000 mg%) with the accuracy of 8.0 +/- 0.3 mg% from a coefficient of variation of 3.5%. Semi-quantitative assay was also possible by using a spot test like Beutler's method. The galactose content in one disc paper (3 mm diameter) of blood containing 5 mg% galactose is approximately 0.1 micrograms. The newly developed method is satisfactorily applicable in neonatal mass screening and clinical cases.

False Positive Reactions↗
PubMed1981

The responses of rat intestinal mucosa, epithelial cell renewal and plasma lipoprotein to intravenous feeding.

Healthy young rats were fed on fat-free diets, 85% of the energy of which derived from glucose and 15% from amino acids. The composition of the intravenous infusates was adequate to maintain body weight during a 6-day experimental period. Mucosal wet and dry weight, and mucosal protein content were highest when the diet was given orally, intermediate when given intravenously, and lowest when fasting. The DNA content of mucosa was significantly lower following intravenous feeding or fasting than after oral feeding, and there was no significant difference between intravenous feeding and fasting. The composition of mucosal protein following intravenous feeding differed from that following oral feeding or fasting. The migration of jejunum epithelial cells was prolonged following intravenous feeding compared with that after oral feeding. The values of plasma albumin and glucose concentration showed no differences between the intravenous and oral feeding groups. In contrast, intravenous feeding greatly lowered the total plasma cholesterol, HDL-cholesterol and HDL-cholesterol/LDL-cholesterol ratio. LDL-cholesterol levels were not changed.

Animals↗
PubMed1981

[Clinical experience with cefotiam in the field of pediatrics (author's transl)].

A clinical study on cefotiam (CTM) was performed in the field of pediatric infection, and the following results were obtained: The number of cases studied were six including 2 cases of U.T.I., 1 case of vaginitis and vulvitis, 1 cervical lymphadenitis, 1 absence of thigh and coxitis. Clinical responses to CTM were excellent in 3 cases, good in 1 cases but there was 1 exception who dropped out because of concurrent use of other antibiotics. As for bacteriological responses, CTM eliminated the pathogens E. coli and P. mirabilis from U.T.I., Staph. epidermidis and P. morganii, from vaginitis and vulvitis, H influenzae and Str. pneumoniae from cervical lymphadenitis and Staph. aureus from abscess of thigh. No side effect was observed except 1 case who showed an elevation of GOT, GPT and LDH. It is uncertain, however, wether this abnormality was resulted from the use of CTM or not, because the other antibiotics were used also.

Age Factors↗
PubMed1980

Sodium n-butyrate induces prostaglandin synthetase activity in mastocytoma P-815 cells.

Cultured mouse mastocytoma P-815 cells were treated with 1 mM sodium n-butyrate for 40 h. The treated cell homogenate showed high activities in synthesizing prostaglandin D2, E2, and F2 alpha. Such activities were virtually absent in untreated cell homogenate. Direct addition of sodium n-butyrate to the homogenate showed no effects. Pre-exposure of cells to acetylsalicylic acid did not diminish the effect of the subsequent treatment with sodium n-butyrate. These data suggest that sodium n-butyrate induces fatty acid cyclooxygenase in P-815 cells.

Animals↗
PubMed1980

Safe limit of hemodilution in cardiopulmonary bypass -comparative analysis between cyanotic and acyanotic congenital heart disease.

A safe limit of hemodilution in cardiopulmonary bypass (CPB) for open heart surgery was investigated by analyzing of the perfusion results of 100 patients with tetralogy of Fallot (TOF) and ventricular septal defect (VSD). The higher perfusion flow was necessary to compensate for the reduced oxygen carrying capacity and to maintain adequate arterial pressure in proportion to the increase in hemodilution. Once the dilution ratio reached over 40% in TOF and 50% in VSD, however, adequate oxygen transfer and stable hemodynamic conditions could not be maintained. The former was due to inadequate oxygen delivery and the latter to an impaired venous return. In these cases, various complications caused by residual diluent in the body space despite of extensive diuretic therapy occurred immediately postop. The safe limit of hemodilution is 50%. However, that of cyanotic disease, even in the presence of remarkable polycythemia, must be limited to less than 40%.

Cardiopulmonary Bypass↗
PubMed1980

Enhancement of prostaglandin synthesizing activity by the treatment with sodium n-butyrate on cloned mastocytoma cells and various other tissue cell lines.

We have compared the effects of n-butyrate on the prostaglandin synthesizing activities of cloned mouse mastocytoma cells, and various other tissue culture cell lines. Cells were treated with 1 mM n-butyrate for 40 hrs before harvesting. Prostaglandin synthesizing activities of the treated and the control cells were examined in a cell-free assay system. The treatment of some of the cloned mastocytoma cells with n-butyrate brought about the synthesis of prostaglandin D2, E2 and F2 alpha that were not synthesized by the control cells. The treatment of epithelial liver cells (BC-90) also resulted in the formation of 6-keto-prostaglandin F1 alpha which was not formed by the control cells. However, n-butyrate caused relatively small changes in the prostaglandin synthesizing activities of other clones of mastocytoma cells, mouse hepatoma cells, HeLa cells, rat granuloma cells and human embryonic fibroblasts. These data suggest differential effects of n-butyrate on different types of cultured cells.

Animals↗
PubMed1980

Prostaglandin analogues possessing antinidatory effects. 2. Modification of the alpha chain.

Additional double bonds were introduced into the alpha chain in 16-phenoxy-, 16-(3-chlorophenoxy)-, 16-[3-(tri-fluoromethyl)phenoxy]-, and 16-(4-chlorophenoxy)-17,18,19,20-tetranorprostaglandins which have antinidatory effects. Of these analogues, the delta 3-cis-delta 5 analogues 23b is 1200 times more potent than prostaglandin F2 alpha in antinidatory effect in the rat and more potent than any other known prostaglandin analogues.

Abortifacient Agents, Nonsteroidal↗
PubMed1980

Preliminary evidence for the conversion of dog renin into a higher-molecular-weight form by cold storage.

1. A soluble fraction of renal cortical homogenate (cytosol) and renin extracted from isolated renin granules of the dog kidney were kept at 0 degrees C. 2. Although the molecular weight of the renin in the cytosol on day 1 was estimated to be about 40 000 by gel filtration, the renin was completely converted into a higher-molecular-weight form (60 000) by day 7. The renin in the granules kept its molecular size of 40 000 during cold storage. 3. This type of molecular-weight conversion could be performed without protease inhibitors. 4. Dithiothreitol neither inhibited the conversion into the higher-molecular-weight form of renin during cold storage nor led to a reduction in the molecular weight of renin, although the oxidation of thiol groups has been proposed as the mechanism for the molecular-weight conversion of renin. 5. Keeping a mixture of renin from the granules and crude renin-binding substance at 0 degrees C for 7 days resulted in the conversion of the renin into the higher-molecular-weight form, indicating that the renin-binding substance we have previously described is required for the conversion during cold storage. 6. Acidification caused the higher-molecular-weight form of renin formed in the cytosol to change to the lower-molecular-weight form, with a concomitant increase in activity of about 50%.

Animals↗
PubMed1980

Interconversion between high- and low-molecular-weight forms of renin in dog kidney.

1. The low-molecular-weight (40 000) form of renin was converted into the high-molecular-weight (60 000) form of renin with sulphydryl oxidation, and the high-molecular-weight form of renin was re-converted into the low-molecular-weight form with a reduction of disulphide bonds in the renal cortical homogenate of the dog. Therefore, the low- and high-molecular-weight forms of renin were interconvertible. 2. The formation of high-molecular-weight form of renin required a renin binding substance which was found to be included in the cytosol fraction of kidney cortex of the dog. 3. The renin binding substance of the dog was unstable to heat and low pH, but vitally resistant to Triton X-100 and chloroform. It did not bind to concanavalin A Sepharose 4B. 4. The renin binding substance was eluted in the molecular-weight region between 156 000 and 60 000 on Sephadex G-200, and such apparent molecular weight was not altered by urea at 4 mol/l; thus molecular weight greater than the theoretically expected value of 20 000 was indicated.

Animals↗
PubMed1980

Effect of reducing agents on the solubilization of renal sodium and potassium dependent ATPase with detergent.

A high concentration (0.5 M) of a reducing agent such as dithiothreitol or 2-mercaptoethanol inactivated both crude (microsomal) and purified preparations of Na+,K+-ATPase only in the presence of detergent. The concentration of SDS needed for inactivation by a reducing agent was low (around 0.3 mg/ml), and was similar to that required for activation in the absence of reduction. The subunits of the enzyme after inactivation with a reducing agent were not sedimented by centrifugation at 100,000 x g for 1 h. Electron microscopic observation of the inactivated enzyme revealed that membranous structures were dominant in the pellet obtained by centrifugation, whereas many particles were present in the supernatant. These results suggest that Na+,K+-ATPase was inactivated by reduction of disulfide bond(s) embedded within the lipid bilayer in the presence of detergent, and that the subunits of the resulting enzyme were no longer bound to the membrane.

Animals↗
PubMed1980

Combined use of phenoxybenzamine and dopamine for low cardiac output syndrome in children at withdrawal from cardiopulmonary bypass.

The combined use of phenoxybenzamine and dopamine was applied in infants and children when it was difficult to come off cardiopulmonary bypass for low cardiac output. The rationale of this method is to prevent the alpha-adrenergic action of dopamine by phenoxybenzamine and to encourage the beta-adrenergic and direct specific action of dopamine. Dopamine was used in dosage of 10 to 30 micrograms/kg per min after the additional administration of a half of the initial dosage of phenoxybenzamine; this was infused by drip always in a dosage of 0.5 to 1.0 mg/kg during the first half of cardiopulmonary bypass. It was possible to come off cardiopulmonary bypass with a stable haemodynamic state (mean arterial pressure more than 60 mmHg and total peripheral vascular resistance less than 2000 bynes s cm-5) and a good urinary output.

Cardiac Output, Low↗