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Biomedical subjects

M Tsukada

Publications and source records attributed to M Tsukada.

At least 145 records · Page 8Linked to original sources
PubMed1987

Detection of antibodies to anterior pituitary cell surface membrane with insulin dependent diabetes mellitus and adrenocorticotropic hormone deficiency.

Autoantibodies for anterior pituitary cell surface membrane (PitCSA) were assayed by immunofluorescence method using GH3 cells (rat GH and prolactin secreting cell) and AtT-20 cells (mouse adrenocorticotropic hormone secreting cell) as antigens. Out of 18 insulin dependent diabetic patients who were positive for antibodies to islet cell surface membrane (ICSA), 3 cases (16.7%) were positive for antibodies to GH3 cells and 12 cases (66.7%) were positive for antibodies to AtT-20 cells. Moreover, out of 18 insulin dependent diabetic patients who were negative for ICSA, 2 (11.1%) and 6 cases (33.3%) were positive for antibodies to GH3 cells and AtT-20 cells, respectively. Among 5 adrenocorticotropic hormone (ACTH) deficient patients, all of the sera were positive for antibodies to AtT-20 cells. These results suggested that PitCSA and ICSA have independent features, though both are closely related, and that PitCSA was one of the significant immunological markers often observed in the sera of the patients with insulin dependent diabetes mellitus (IDDM) and ACTH deficiency.

Adrenocorticotropic Hormone↗
PubMed1986

Thrombolytic effect of single-chain pro-urokinase in a rabbit jugular vein thrombosis model.

The thrombolytic effect of single-chain pro-urokinase (SCPU) was examined in the rabbit using a jugular vein thrombosis model. Infusion of a low dose (120,000 IU/kg) of either urokinase (UK) or SCPU did not produce any significant thrombolysis. However, UK administration at such a low dose caused 20% degradation of circulating fibrinogen. A high dose (480,000 IU/kg) caused significant thrombolysis. The degree of fibrinogenolysis was about 20% in SCPU, but about 80% in UK. The thrombolytic efficiency of SCPU was thus about 3 times larger than that of UK. Analysis of fibrinolytic parameters such as plasminogen, alpha 2-plasmin inhibitor, etc. suggested that UK caused systemic activation of the fibrinolytic system, but SCPU, locally limited activation on the fibrin surface (fibrinolysis). These results indicate that SCPU represents a highly efficient thrombolytic agent without producing fibrinogenolysis.

Animals↗
PubMed1986

Enhancement of vasoconstrictor responses to thiopental and barium chloride by intraluminal treatment with saponin in isolated canine mesenteric arteries.

Using a cannula-insertion method for isolated arteries, the effects of thiopental, barium chloride, and prostaglandin F2 alpha were investigated on isolated canine mesenteric arteries with and without saponin treatment. Thiopental caused a vasoconstriction in a dose-related manner. The observed vasoconstriction was not influenced by phentolamine in doses which inhibited norepinephrine-induced vasoconstriction. After intraluminal saponin treatment, thiopental- and barium chloride-induced constrictions were significantly enhanced, but prostaglandin F2 alpha-induced constriction was not potentiated. It is suggested that vasoconstrictor responses to thiopental and barium chloride may be enhanced by an increase in calcium influx after disrupting the endothelium of the artery.

Animals↗
PubMed1986

Comparison of vasoconstrictor actions of norepinephrine and potassium chloride before and after damage of endothelium by saponin.

Using isolated and perfused mesenteric arterial preparations of dogs, vasoconstrictor responses to intraluminal norepinephrine and potassium chloride were investigated in the presence and absence of the endothelium. Intraluminal administration of saponin readily removed the endothelium. Saponin (1-3 mg) caused an increase in perfusion pressure, and then approximately 20 min later perfusion pressure became stable at a somewhat higher level than that of the control. A larger dose of saponin (10 mg) caused a tremendous but temporary increase of perfusion pressure. KCl-induced vasoconstriction was significantly enhanced by pretreatment with 0.3, 1, and 3 mg saponin, but norepinephrine-induced constriction was not modified significantly. Moreover, it was demonstrated that diltiazem, a potent Ca antagonist, inhibited the KCl-induced vasoconstriction more readily in the absence than in the presence of the endothelium.

Animals↗
PubMed1986

Testicular histology and function following long-term chemotherapy of acute leukemia in children and outcome of the patients who received testicular biopsy.

Wedge biopsy of the testis was performed in 46 children who had received long-term chemotherapy for acute lymphoblastic leukemia. Occult testicular infiltration was noted in three children (6.5%). Two of three children with biopsy-proven infiltration died of systemic disease in spite of local irradiation and reinduction chemotherapy. Six of 43 children shown to be negative by testicular biopsy relapsed 11 months to 15 years later, and 3 of 6 patients died of systemic disease, but none of the cases developed testicular disease. Chemotherapy-induced gonadal damage was observed in 30 of 46 children, and tubular damage was occasionally still seen 4 years after cessation of treatment. Although gonadal damage usually depends on the cumulative dosage of cyclophosphamide, intact tubular fertility index was found in several children who had received a greater dose of cyclophosphamide intermittently. Induction and maintenance chemotherapy for acute lymphoblastic leukemia had little influence on hormonal function. Testicular biopsy at the time of cessation of chemotherapy seems to be worthwhile for the subsequent strategy of treatment, and long-term surveillance for gonadal damage of long-term survivors will be required.

Age Factors↗
PubMed1986

Potentiating effects of angiotensin II on norepinephrine-induced vasoconstriction in isolated and perfused dog mesenteric arteries.

Effects of angiotensin II on norepinephrine- and KCl-induced vasoconstrictions were investigated in isolated canine mesenteric arteries which were perfused with Krebs' solution at 37 degrees C. Angiotensin Ii at 0.03-0.3 microgram showed tachyphylaxis in the injection intervals used (10, 20 or 30 min intervals). After treatment with angiotensin II (0.18-1.8 microgram), norepinephrine- and KCl-induced constrictions were consistently potentiated. Imipramine which blocked tyramine-induced action did not significantly influence norepinephrine-induced constriction. pretreatments with both angiotensin II and indomethacin enhanced norepinephrine-induced constriction much greater than that with angiotensin II alone. It is suggested that angiotensin II may modify intracellular Ca movements and prostaglandin production induced by norepinephrine.

Angiotensin II↗
PubMed1986

Angiotensin II-induced tachyphylactic constrictions in isolated and perfused canine mesenteric arteries.

The stainless steel cannula inserting method was used to investigate the effects of angiotensin II on isolated and perfused dog mesenteric arteries with and without indomethacin treatment, or with and without intraluminal saponin-treatment which removed the endothelium. In non-treated preparations, angiotensin II was intraluminally administered repetitively at 10, 20, 30 or 60 min inervals. Each period of angiotensin II causes tachyphylaxis. The order of degree of tachyphylaxis was 10 greater than 20 greater than 30 greater than 60 min intervals. Relatively large doses much readily caused tachyphylaxis. Tachyphylaxis was not affected by phentolamine-treatment preparations. In indomethacin (5 mg)-treated preparations, the angiotensin II-induced tachyphylaxis was significantly less than that in non-treated ones. In small doses of angiotensin II, tachyphylaxis did not appear in the majority of cases in indomethacin-treated preparations. In deendothelial preparations which were induced by intraluminal administration of saponin (1 and 3 mg), the tachyphylaxis was induced similar to non-saponin treated preparations. It is concluded that prostaglandin may partially participate in induction of angiotensin-induced tachyphylaxis, the prostaglandin may be synthesized in the inside of vasculature, and a large dose of angiotensin II induces tachyphylaxis unrelated to production of prostaglandin.

Angiotensin II↗
PubMed1986

Heterogeneity of anterior pituitary cell antibodies detected in insulin-dependent diabetes mellitus and adrenocorticotropic hormone deficiency.

A sensitive assay method for pituitary cell antibodies (PitCA) was established by a biotin/avidin system using rat pituitary. Results in 24 cases out of 81 insulin-dependent diabetic patients and 10 cases of 21 adrenocorticotropic hormone (ACTH) deficient patients were positive for autoantibodies to anterior pituitary cell cytoplasm. PitCA observed in the sera of insulin-dependent diabetic patients were suspected of being pituitary specific and independent with islet cell antibodies (ICA) and islet cell surface antibodies (ICSA). In the sera of ACTH deficient patients, PitCA were frequently absorbed with liver acetone powder. Populations of insulin-dependent diabetes mellitus (IDDM) are almost equal in males and females. A total of 16 cases out of 21 ACTH deficient patients were female. These results suggest that heterogenous PitCA are involved in the sera of those patients with IDDM and ACTH deficiency.

Adrenocorticotropic Hormone↗
PubMed1986

Pharmacological analysis of vasoconstrictor responses to ATP of isolated, perfused dog mesenteric arteries.

The stainless steel cannula inserting method was used to analyze the characteristics of the vasoconstriction induced by ATP in isolated, perfused dog mesenteric arteries. A dose of 100-1000 micrograms of ATP induced vasoconstriction. It was produced repetitively at 20-min intervals. The vasoconstriction was not modified by phentolamine in doses which completely inhibited norepinephrine-induced vasoconstriction. Aminophylline significantly suppressed ATP-induced vasoconstrictions. KCl-induced vasoconstriction was significantly depressed by a potent Ca antagonist, diltiazem. ATP-induced vasoconstriction was also significantly suppressed by diltiazem but to a lesser degree. ATP-induced vasoconstriction was not significantly suppressed by 30 and 100 micrograms of dipyridamole. After treatment with intraluminal saponin (0.3-3 mg) which caused a disappearance of the vascular endothelium, the ATP-induced vasoconstrictor response was significantly enhanced. From these results it is concluded that ATP-induced vasoconstriction may be mediated via P1-purinoceptors and be partially due to increases in activation of Ca inward current.

Adenosine Triphosphate↗
PubMed1985

Effect of chronic administration of acetaldehyde by inhalation on (Na+ + K+)-activated adenosine triphosphatase activity of rat brain membranes.

The effect of chronic acetaldehyde inhalation on (Na+ + K+)-ATPase (EC 3.6.1.3) activities of subcellular fractions of the rat cerebral cortex was studied. Chronic administration of acetaldehyde by inhalation for 4-21 weeks caused significant increases in the enzyme activities of both the synaptosomal plasma membrane (SPM) fraction and the microsomal (MC) fraction. This indicates the change in neural membrane functions of the brain after acetaldehyde treatment. Mg2+-ATPase activities of both subcellular fractions remained unchanged after acetaldehyde treatment.

Acetaldehyde↗