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Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 847 records · Page 47Linked to original sources
PubMed1984

Alterations in erythrocyte membrane lipids in abetalipoproteinemia: phospholipid and fatty acyl composition.

Scanning electron microscopic observation revealed that there were wide variations including typical acanthocytes in morphology of erythrocytes from a patient with abetalipoproteinemia. The erythrocyte membrane phospholipids and cholesterol contents from a patient was higher by 25% compared to an age-matched control subject. Analysis of phospholipid composition of red blood cells showed an increase of sphingomyelin (25.1----30.1%) with a concomitant decrease of lecithin (27.5----21.0%). Thus, the sphingomyelin/lecithin ratio was increased dramatically (0.91----1.43). As for fatty acyl chain composition of main phospholipids, an increased percentage of palmitic acid and docosahexaenoic acid and a decreased proportion of arachidonic acid and lignoceric acid were observed for sphingomyelin. There was an increment of palmitic acid which was accompanied with a decrease of linoleic acid in lecithin. On the other hand, no significant difference was shown in the fatty acid composition of phosphatidylethanolamine and phosphatidylserine plus phosphatidylinositol between a patient and control.

Abetalipoproteinemia↗
PubMed1984

Prostaglandin D2 lowers nuclear DNA polymerase activity in cultured mastocytoma cells.

Prostaglandin D2 strongly inhibited growth of cultured mastocytoma P-815, 2-E-6 cells, which were established and cloned from mouse mast tumor cells. The inhibition was dose-dependent (IC50=2.09 x 10-5 M). Prostaglandin D2 also inhibited the DNA synthesizing activity of the cells dose-dependently. We next measured the activities of endogenous DNA polymerases extracted from untreated and prostaglandin D2-treated cells. Prostaglandin D2-treated cells were the same suggesting there was no gross change in the size of the enzyme. Prostaglandin D2 pretreatment of the cells reduced endogenous DNA polymerase beta activity to 68% of the control value; the sedimentation coefficients of the enzymes from treated and untreated cells were both 3.5 S. Interestingly, prostaglandin D2 had no direct inhibitory effect on the activity of either DNA polymerase alpha or beta. Our results indicate that the activities of DNA polymerase alpha and beta are lower in prostaglandin D2-treated mastocytoma cells. This finding accounts for the lower level of DNA synthesis in these cells.

Animals↗
PubMed1984

Kallikrein-kinin and renin-angiotensin systems in rat renal lymph.

Rat renal lymph contains 254 +/- 17 ng/ml (means +/- SEM, N = 20) of immunoreactive glandular kallikrein. Like the immunoreactive glandular kallikrein in plasma, it is biologically inactive. Gel filtration of renal lymph reveals profiles for immunoreactive glandular kallikrein, protein, and inhibition of trypsin and kallikrein which resemble those seen for plasma except that high molecular weight plasma components are reduced or missing in renal lymph. In contrast, gel filtration of thoracic lymph reveals immunoreactive glandular kallikrein and protein profiles which are indistinguishable from those seen with plasma. Renin levels are 170-fold higher in renal lymph than in thoracic lymph while angiotensin-converting enzyme levels are only 16% those of thoracic lymph. In keeping with the high renin and low converting enzyme activities, renal lymph contains high levels of angiotensin I. Immunoreactive glandular kallikrein levels in renal lymph, thoracic lymph and plasma do not show the striking differences observed for renin.

Angiotensin I↗
PubMed1984

A study of sequential anastomoses in aortocoronary bypass surgery--internal configuration by the casting injection technique.

Presently, sequential aortocoronary bypass grafting is a widely used method for the revascularization of multiple coronary vessel disease. In this study, the internal configurations of the anastomosed portions were investigated by casting models and the following results were obtained: In crossed side-to-side anastomoses with longitudinal incisions, the anastomosed area for the incised length was larger than in the other anastomosis techniques. Interrupted sutures produced a larger anastomosed area for the incised length than other suture techniques. Crossed side-to-side anastomoses with one longitudinal and one transverse incision resulted in the most frequent reoccurrence of narrowings.

Animals↗
PubMed1984

Excretion and metabolism of dopa and dopamine by isolated perfused rat kidney.

The renal metabolism and handling of dopa and dopamine were studied with the use of the isolated perfused rat kidney to elucidate the source of urinary dopamine. Dopa added to the perfusate was rapidly metabolized, and a significant amount of urinary dopamine excretion was observed, whereas dopa was not detected in the urine. When the perfusate dopa concentration was near the plasma dopa concentration in normal rats, urinary dopamine excretion was comparable with physiological values. Carbidopa, a dopa decarboxylase blocker, added to the perfusate markedly reduced the urinary excretion of dopamine. When the physiological concentration of dopamine was added to the medium, the perfusate dopamine rapidly decreased and urinary dopamine excretion was much less than that seen in normal rats. In studies with nonfiltering kidneys, a marked decrease of dopa and slight increase of dopamine in the perfusate were observed. It is suggested that the process of glomerular filtration and tubular reuptake of dopa is not essential for renal dopamine formation. These data indicate that urinary free dopamine is mainly derived from plasma dopa, which is converted by dopa decarboxylase in the kidney.

Animals↗
PubMed1984

Intrarenal beta-adrenergic stimulation enhances excretion of urinary lysosomal enzyme in anesthetized dogs.

The effects of intrarenal administration of isoproterenol on excretion of urinary enzymes were examined in dogs. Urinary N-acetyl-beta-D-glucosaminidase (NAG) and glutamyl transpeptidase (gamma-GTP) originated from lysosomes and the brush border membrane of the kidney, respectively. NAG excretion was elevated for 10 min by isoproterenol (0.2 microgram/kg/min) without a drastic change in glomerular filtration rate and renal blood flow. This elevation was inhibited by pretreatment with d,l-propranolol (0.6 mg/kg bolus injection 0.3 mg/kg/30 min) but less so by d-propranolol. Urinary gamma-GTP excretion was little affected by isoproterenol. In light of these findings, the possibility that beta-receptors may be involved in the excretion of NAG has to be considered.

Animals↗
PubMed1984

Roles of endogenous angiotensin II or kinin in the mechanism of altered renal vascular responsiveness to angiotensin II following acute blood volume expansion in the dog.

To examine the role of endogenous angiotensin II or kinins in the mechanism of the increased renal vascular reactivity to exogenous angiotensin II following acute blood volume expansion, we examined whether captopril, a converting enzyme inhibitor, can prevent the increase in renal vascular response in anesthetized dogs. Pretreatment of dogs with captopril increased plasma renin activity, but it did not affect systemic blood pressure, renal blood flow and renal vascular resistance. Acute blood volume expansion with saline suppressed plasma renin activity in dogs with or without pretreatment with captopril. Basal level of renal vascular reactivity to angiotensin II was increased by pretreatment with captopril. In the control animals, acute blood volume expansion enhanced renal vascular reactivity to angiotensin II but not norepinephrine. The enhanced renal vascular reactivity to angiotensin II, however, was not prevented by the captopril treatment. The failure of captopril to prevent an increase in renal vascular reactivity to angiotensin II following acute blood volume expansion was associated with an increase in urinary excretion of bradykinin. These data suggest that endogenous angiotensin II level is not necessarily a determinant for vascular reactivity to exogenous angiotensin II, especially in the case of acute blood volume expansion.

Angiotensin II↗
PubMed1984

Effect of adrenaline on steroidogenesis in primary cultured bovine adrenocortical cells.

In primary 2-day cultured bovine adrenocortical cells, adrenaline stimulated the steroidogenesis, while the effect of adrenaline did not appear in the freshly isolated cells. Thus the primary 2-day cultured cells were used to study the effect of adrenaline on steroidogenesis. Adrenaline showed the steroidogenesis-stimulating effect at concentrations higher than 10(-9) M, and the maximum effect was obtained between 10(-6) M and 10(-5) M in the primary 2-day cultured cells. The maximum effect of adrenaline was 50-70% of that of adrenocorticotropic hormone (ACTH). Noradrenaline, isoproterenol and phenylephrine also stimulated the steroidogenesis. However, the order of the potency was isoproterenol much greater than adrenaline = noradrenaline much much greater than phenylephrine. Propranolol and alprenolol inhibited the effect of adrenaline, but phenoxybenzamine and phentolamine did not inhibit the effect. Moreover, adrenaline stimulated the cyclic AMP production dose-dependently at concentrations higher than 10(-8) M. These results suggest that there are steroidogenesis-linked adrenergic receptors in primary 2-day cultured bovine adrenocortical cell membrane and that the steroidogenesis-stimulating effect of adrenaline occurs through the beta-adrenergic receptor.

Adrenal Cortex↗
PubMed1984

[Plasma gastrin and secretin levels in patients with carcinoma of the esophagus before and after operation].

Twenty-two patients with esophageal cancer (8: preoperative, 8: one-month after surgery, and 6: more than 3 months after surgery) were orally loaded with 50 g of glucose, to determine the plasma gastrin levels. They were also loaded with oral 0.1N hydrochloride preoperatively and also one month after operation to examine the secretion kinetics of plasma secretin. In addition, the correlation between the G-cell (gastrin secretory cell) population in the pyloric region of the postoperative intrathoracic stomach and the plasma gastrin was investigated. The following results were obtained. Hypergastrinemia developed one month after surgery, but after 3 months or later, plasma gastrin levels almost returned to normal. Plasma secretin levels tended to decrease postoperatively; however, no statistically significant differences were observed. G-cell stain by the enzyme antibody method revealed hyperplasia of G-cells in some of the hypergastrinemic cases without accompanying atrophy of the pyloric mucosa and/or the intestinal epithelial metaplasia, although there were some hypergastrinemic cases with a decrease of G-cells due to the atrophy of the pyloric mucosa and/or the intestinal epithelial metaplasia. In the latter cases, gastrin was thought to be secreted probably from the duodenal mucosa.

Aged↗
PubMed1984

[Control of multiple skin and lung metastasis of malignant melanoma by combined DAV and OK-432 chemoimmunotherapy in association with large-scale administration of indomethacin].

Skin metastasis of malignant melanoma has been difficult to control by chemoimmunotherapy. We report a case of melanoma with marked reduction of multiple skin and lung metastasis and an improved cell-mediated immunity using combined DAV (DTIC, ACNU, Vincristine) and OK-432 chemoimmunotherapy in association with doses of indomethacin administered over a long period (250 mg/day, 6 months) to relieve the cancerous pain.

Aged↗