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Biomedical subjects

T Okamura

Publications and source records attributed to T Okamura.

At least 703 records · Page 39Linked to original sources
PubMed1984

Intraoperative radiotherapy for advanced carcinoma of the pancreas.

A detailed retrospective analysis of the efficacy of intraoperative radiotherapy (IOR) in advanced carcinoma of the pancreas is presented. During a 10-year period from 1973 through 1982, 70 patients with advanced carcinoma of the pancreas were treated by multimodal methods, separate or combined therapy of surgery, IOR, and chemotherapy in two different institutions. Among these, 33 patients underwent IOR, mostly combined with additive surgery. A single dose of 20.1 to 40.0 Gy with 8 to 25 meV electrons was delivered through radiation cones ranging from 6 to 10 cm in diameter. Excellent relief was noticed in 50% of the patients who had complained of pain. Among Stage IV patients, a significant difference of survival rate was observed between IOR and control groups (P less than 0.05); the mean survival time of the IOR group was 4.6 +/- 2.6 (SD) and that of the control group 2.5 +/- 1.4 (SD) months. Intraoperative radiotherapy proved to be effective in prolonging the survival of patients with advanced stage of the lesion.

Adult↗
PubMed1984

Heterogeneity in the response to vasoconstrictors of isolated dog proximal and distal middle cerebral arteries.

Responses to vasoconstrictor agents were compared in helical strips of proximal and distal middle cerebral arteries isolated from the same dogs. Contractions induced by 30 mM K+ per cross-sectional areas in the large and small artery strips did not differ significantly so that contractions induced by the agents could be compared relative to those induced by K+. The contractions induced by serotonin were greater in the proximal than in the distal arteries. Histamine produced a greater contraction in the proximal arteries under resting conditions. Distal arteries partially precontracted with prostaglandin F2 alpha responded to histamine with relaxations. The histamine-induced contraction was attenuated by chlorpheniramine, whereas the relaxation was suppressed by cimetidine. Prostaglandin F2 alpha or carbocyclic thromboxane A2 produced similar magnitudes of contractions in the proximal and distal arteries. Thrombin contracted the distal arteries to a greater extent. Contractions induced by norepinephrine or bradykinin did not differ in the proximal and distal arteries. It may be concluded that the ratio of histaminergic H1 and H2 receptor functions decreases peripherally along middle cerebral arteries, whereas the contractile response to bradykinin was not influenced in these arteries of a relatively short distance. The functions of receptor sites for serotonin and thrombin appear to be quite different in large and small cerebral arteries of such a short distance, but alpha-adrenoceptor functions seem to be identical.

Animals↗
PubMed1984

Effects of intravesical instillation of antitumor chemotherapeutic agents on bladder carcinogenesis in rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine.

The effects of intravesical instillation of Adriamycin (doxorubicin) (ADR), and mitomycin C (MMC), as inhibitors of development of rat bladder tumors, were examined in rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). Intravesical instillation of ADR or MMC once a week for 12 weeks into rats pretreated with BBN for 4 weeks markedly enhanced development of bladder tumors. That is, one week after the end of intravesical instillation of these compounds the incidence of papillary or nodular hyperplasias, namely preneoplastic lesions, was significantly increased, and at the end of the experiment the incidence of not only papillary or nodular hyperplasias but also of papillomas and cancers was significantly increased. These results indicate that the intravesical instillation of ADR or MMC promotes two-stage bladder carcinogenesis in rats.

Animals↗
PubMed1984

Cytophotometric DNA analysis of mucosal and submucosal carcinoma of the esophagus.

Cell nuclear deoxyribonucleic acid (DNA) content was microspectrophotometrically determined in 35 cases of mucosal and submucosal carcinoma of the esophagus. DNA distribution pattern was classified into types I, II, III, and IV, according to the degree of dispersion on the DNA histogram, in the order of wider distribution. Patients with types I and II (relatively regular in DNA distribution) had an uneventful postoperative course and no recurrence, whereas 3 of 15 (20%), and 5 of 9 (55.6%) with type III and type IV, respectively (widely scattered DNA distribution), died following a recurrence. Cytophotometric DNA analysis of the cancer cells reflected well the outcome in patients with esophageal carcinoma. These results suggest the potential usefulness of cytophotometric DNA analysis for assessing the prognosis, even in the early stage of esophageal carcinoma.

Adult↗
PubMed1984

Generation of angiotensins in cultured pheochromocytoma cells.

Cultured rat pheochromocytoma cells, PC-12, were found to contain renin-like activity. The activity which was inhibited by monospecific antibodies to rat renal renin showed a pH optimum between 6 and 7, indicating that it was a specific renin. The cells also contained angiotensin I and angiotensin I converting enzyme. Angiotensin II/III were also detected in lysate. These findings indicated an intrinsic pathway of angiotensin formation in pheochromocytoma. The formation of angiotensins in pheochromocytoma cells suggests modulating functions of angiotensin on neurotransmitter release from adrenal medulla.

Adrenal Medulla↗
PubMed1984

Modification by yohimbine and prazosin of the mechanical response of isolated dog mesenteric, renal and coronary arteries to transmural stimulation and norepinephrine.

Some functions of pre- and postsynaptic alpha-receptors were compared in isolated dog arteries. In mesenteric and renal arteries, contractile responses to transmural electrical stimulation were potentiated by yohimbine, a selective alpha 2-antagonist; the potentiation was greater in mesenteric arteries. Concentration-response curves for norepinephrine were shifted to the right by high concentrations of yohimbine. Prazosin, a selective alpha 1-antagonist, in low concentrations preferentially attenuated the contractile response to transmural stimulation, when compared with the response to equiactive concentrations of norepinephrine. Relaxant responses of coronary arteries to transmural stimulation were also potentiated by yohimbine. Relaxations induced by norepinephrine were not influenced by yohimbine but were potentiated by prazosin. Contractile responses of coronary arteries treated with propranolol to transmural stimulation were abolished by prazosin. It is concluded that the involvement of presynaptic alpha 2-receptors in the negative feedback mechanism in transmitter release differs in a variety of dog arteries and that the adrenoceptors subserving contraction are of both subtypes (alpha 1 and alpha 2) in the mesenteric and renal arteries, but only of the alpha 1 subtype in coronary artery.

Animals↗
PubMed1984

Growth patterns of gastric carcinoma detected by mass survey.

Two hundred and sixty-seven cases of gastric carcinoma detected by mass survey included 196 discovered at the first examination (Group A) and 71 noted at the annual sequential examination (Group B) were analyzed in terms of growth pattern and prognosis. The incidence of early carcinoma was 54.9 per cent in Group B higher than 35.7 per cent in Group A. In early carcinoma, the superficially spreading (SUPER) type of carcinoma was more common in Group A than in Group B. On the contrary, the penetrating growth (PEN) type of carcinoma was more frequently found in Group B than in Group A. About eighty per cent of those with an advanced carcinoma, in both groups, was the advanced PEN type. The outcome of the patients in Group B was more favorable. These results support the hypothesis that the majority of advanced carcinoma is derived from the PEN type of early carcinoma. Early detection of the PEN type of carcinoma is mandatory.

Humans↗
PubMed1984

Combined treatment of coenzyme Q10 and aprotinin with intraaortic balloon pumping following aorto-coronary bypass surgery.

The effect of combined treatment of coenzyme Q10 (CoQ10) and aprotinin with intra-aortic balloon pumping (IABP) was evaluated in patients who underwent aorto-coronary bypass surgery. Forty-one patients were divided into two groups. Group A (27) were treated by IABP only and Group B (14) were treated by the concomitant use of CoQ10 and aprotinin with IABP. Both groups were subdivided into two groups with regard to the ability to be weaned from IABP (Group A-I, Group B-I) or the inability (Group A-II, Group B-II). CoQ10 was administrated intravenously at doses of 5-10 mg/kg/day and aprotinin was infused at doses 5,000-10,000 KU/kg/day. The percentile incidence of ability to be weaned from IABP was 93 per cent (13/14) in Group B was higher than that of 74 per cent (20/27) in Group A. There were no significant differences among Group A-I, Group A-II, and Group B-I with regard to preoperative and intraoperative factors. Serum GOT and CPK levels on the first postoperative day were significantly higher in Group A-II and Group B-I than those in Group A-I but there was no significant difference between GOT or CPK levels in Group A-II and Group B-I. These results suggest that concomitant treatment of CoQ10 and aprotinin with IABP leads to an improvement in postoperative low cardiac output syndrome.

Aprotinin↗
PubMed1984

Bidirectional effects of splenectomy on the growth of syngeneic tumor in mice.

The effects of splenectomy on tumor growth following inoculation with a relatively large number of cells (1 X 10(7) ) and a smaller number of cells (5 X 10(5) ) of Meth I tumor were studied. When 1 X 10(7) tumor cells were inoculated, tumor growth in splenectomized mice was depressed, while tumor in sham-operated mice grew progressively. On the contrary, when 5 X 10(5) tumor cells were inoculated, the tumor take was lower in sham-operated than in splenectomized mice. The spleen cells from mice inoculated with either a large or small number of tumor cells, showed an equally potent cytotoxic activity, but no detectable suppressor cell activity. On the other hand, the activity of immunosuppressive factor was detected in sera from mice inoculated with 1 X 10(7) tumor cells, but not in those given 5 X 10(5) cells. The effect of splenectomy on tumor growth is, thus, bidirectional, depending on the dose of tumor cells inoculated.

Animals↗
PubMed1984

Inhibitor of plasminogen activator in human arterial wall. I. Histochemical study.

An inhibitor of urokinase, human urinary plasminogen activator, was found in the media of human arteries using a histochemical method (fibrin slide sandwich technique). Arteriosclerotic lesions, especially atherosclerosis, apparently contained the urokinase inhibitor. The inhibitor did not alter plasmin activity. This inhibitor of urokinase may be involved in regulation of fibrinolysis in arterial wall and thus a significant role in atherogenesis.

Aorta↗
PubMed1984

Inhibitor of plasminogen activator in human arterial wall. II. Biochemical characterization.

Fibrinolytic inhibitor was prepared from human aortas and some of its biochemical properties were investigated. The fibrinolytic inhibitor suppressed urokinase activity, but did not inhibit plasmin activity when assayed by fibrin plate method and synthetic fluorogenic substrate method. The urokinase inhibitor was a glycoprotein and migrated similar to alpha-globulin upon fibrin-agar electrophoresis. The molecular weight determined by gel filtration was approximately 98,000. The urokinase inhibitor was immunologically different from other known plasma protease inhibitors, such as alpha 2-plasmin inhibitor, alpha 2-macroglobulin, and alpha 2-antitrypsin. The interaction of urokinase with the inhibitor was dose-dependent. Progressive inactivation of urokinase occurred by increasing time of incubation with the inhibitor at 37 degrees C, and over 90% inhibition of urokinase required 30 min of incubation. The inhibitor of plasminogen activator in human aorta may be noteworthy in relation to thrombogenesis and atherogenesis.

Arteries↗
PubMed1984

Release of active and inactive renin from hog renal cortical slices in vitro.

Both inactive and active renin were released from renal cortical slices of the hog. Isoproterenol, prostaglandin E1, and dibutyryl cAMP stimulated the release of both inactive and active renin. Renal kallikrein caused selective stimulation of the release of active renin and suppressed the release of inactive renin. Bradykinin and kallidin did not stimulate renin release. The effect of kallikrein was abolished by aprotinin but not by indomethacin. These observations indicate that the effect of kallikrein is not mediated via kinin formation or prostaglandin generation. The data suggest that there may be at least two types of mechanism for renin release from hog kidney. One is of the nonselective type by which both active and inactive renin are released, as in the case of beta-adrenergic or prostaglandin stimulation. The other is a selective mechanism by which only active renin is preferentially released, as in the case of urinary or renal kallikrein stimulation.

1-Methyl-3-isobutylxanthine↗
PubMed1984

[Two cases of cerebral aneurysms combined with polycystic kidneys].

Two cases of cerebral aneurysm combined with polycystic kidneys (PCKs) were presented. Case 1, a 24-year-old hypertensive male, was referred to our clinic owing to sudden onset of severe headache at August 20, 1982. Neurological findings on admission were stuporous, right vitreous hemorrhage (so-called Terson's syndrome), and hypertension. CT scans showed subarachnoid hemorrhage, and right MCA bifurcation aneurysm with marked vasospasms by cerebral angiography was revealed. Intentional delayed operation with V-P shunt was performed. He discharged with mild left upper limb paresis, and visual impairment on the right. Bilateral PCKs were confirmed by postoperative DIP and CT scan. Case 2, a 51-year-old female, who suddenly complained of severe headache, was referred to our department 3 days after subarachnoid hemorrhage. One year previously, she had been pointed out PCKs. Neurological findings on admission at February 29, 1980, were drowsy, left third cranial nerve palsy, and hypertension. Cerebral angiography showed multiple aneurysms (bilateral IC-PC & A-com). Neck clipping (1-IC-PC & A-com) and coating (r-IC-PC) were performed at the next day of admission, and V-P shunt operation was followed about 8 weeks after first operation. About 2 weeks after discharge, she suddenly became loss of consciousness and expired. Autopsy revealed intracerebral hemorrhage in left basal ganglia and thalamus. Both kidneys were PCKs of Potter type 3 and cysts of the liver were also noted. In young hypertensive patients with cerebral aneurysms, it should be in mind whether PCKs may be combined or not, and cerebral angiography in PCKs were reasonable to find out harbored cerebral aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗