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Biomedical subjects

T Konishi

Publications and source records attributed to T Konishi.

At least 19 recordsLinked to original sources
PubMed1992

cAMP-mediated expression of inwardly rectifying potassium channels in cultured mouse Schwann cells.

Voltage-gated ionic currents were recorded from freshly dissociated or cultured mouse Schwann cells obtained from neonatal sciatic nerves by the whole-cell variation of the patch-clamp technique. Schwann cells virtually lost inwardly rectifying potassium (Kir) currents within 2 days after nerve transection or in culture conditions of neonatal sciatic nerves confirming the previous results that axonal signals were suggested to play an important role in the expression of functional Kir channels. To see the effects of adenosine 3',5'-monophosphate (cAMP) analogues or forskolin on the expression of Kir channels in cultured Schwann cells, these agents were added to the culture medium 4 days after the start of the culture, when Kir currents were almost eliminated from cultured Schwann cells. Cultured Schwann cells restored the expression of Kir currents by co-culture with agents which elevate intracellular cAMP level. The dose-response of 8-(4-chlorophenylthio) (CPT) cAMP for the incidence of the expression of Kir currents showed a steep increase in the percentage of cells with Kir currents between 0.02 and 0.1 mM of external CPT cAMP and approximately two thirds of cells had Kir currents in higher concentrations of more than 0.1 mM of CPT cAMP after 4 days of incubation. After removal of CPT cAMP from the culture media after 4 days of incubation, Kir currents disappeared from cells within 2 days. The simultaneous application of cycloheximide (1 microgram/ml), an inhibitor of protein synthesis, with CPT cAMP suppressed the expression of Kir currents for up to 6 days of incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Serial change of iodine-123 metaiodobenzylguanidine (MIBG) myocardial concentration in patients with dilated cardiomyopathy.

Serial change of the metaiodobenzylguanidine iodine-123 (123I-MIBG) myocardial concentration was investigated in patients with dilated cardiomyopathy (DCM). Eight DCM patients and 6 control subjects were examined. After the injection of thallium-201 and 123I-MIBG, planar chest images were obtained simultaneously for both tracers in every 30-60 min over 5 h. Serial changes of myocardial uptake ratio (MUR) were compared for both tracers. In DCM, the initial MUR of 123I-MIBG did not differ significantly from that of the controls. The washout of 123I-MIBG from the myocardium, however, was significantly increased in DCM. In particular, the decrease in the early phase (15-45 min) was significantly larger in DCM than in the controls (21.2% +/- 7.5% vs. 5.3% +/- 4.0%, P less than 0.01), showing a significant negative correlation with the left ventricular ejection fraction (r = -0.72 P less than 0.05). For 201Tl, neither the initial MUR nor the washout rate different significantly between the two. Thus, an early rapid decrease of the 123I-MIBG myocardial concentration might characterize DCM and reflect the severity of this disease.

3-Iodobenzylguanidine↗
PubMed1992

Effects of trapidil (triazolopyrimidine), a platelet-derived growth factor antagonist, in preventing restenosis after percutaneous transluminal coronary angioplasty.

Trapidil (triazolopyrimidine), a platelet-derived growth factor antagonist, is a potential inhibitor of intimal proliferation after percutaneous transluminal coronary angioplasty (PTCA). To study its efficacy, 72 patients were randomized to receive Trapidil (600 mg/day orally for 1 week before PTCA and for 4 to 6 months after PTCA; n = 36) or aspirin and dipyridamole (aspirin, 300 mg/day, and dipyridamole, 150 mg/day; n = 36). At entry, both groups were comparable with regard to age, sex, dilated vessels, severity of pre-PTCA stenosis, residual stenosis after PTCA, and prevalence of coronary risk factors. Repeat coronary angiography was performed 6 months after PTCA. Restenosis, defined as the loss of at least 50% of the gain in luminal diameter accomplished by dilation, was present in seven patients (19.4%) in the trapidil group and 15 patients (41.7%) in the aspirin-dipyridamole group (p less than 0.05). The progression of stenosis in patients with less than 30% residual stenosis was significant in both groups. Furthermore, in the patients with residual stenosis of more than 30%, progression of stenosis was less in the trapidil group than in the aspirin-dipyridamole group. Thus trapidil was useful in preventing intimal proliferation after PTCA, especially in patients with more than 30% residual stenosis after PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1992

Dependence of peak dP/dt and mean ejection rate on load and effect of inotropic agents on the relationship between peak dP/dt and left ventricular developed pressure--assessed in the isolated working rat heart and cardiac muscles.

To examine the effects of preload (mean left atrial pressure) and afterload on two so-called "contractility indices" and the effects of inotropic agents (isoproterenol and calcium) on the relationship between left ventricular developed pressure and peak dP/dt when afterload was increased, we used a modified working rat heart preparation (perfused with Krebs-Henseleit solution bubbled with a 95% O2 -5% CO2 gas mixture at 37 degrees C). The atrium was stimulated at a rate of 240/min. An increase in preload from 5 to 15 mmHg caused an increase in peak dP/dt from 1,711 +/- 293 mmHg/s to 1,971 +/- 387 mmHg/s (p less than 0.001, n = 15), and an increase in the mean systolic ejection rate from 1.28 +/- 0.31 ml/s to 2.74 +/- 0.80 ml/s (p less than 0.001). An increase in afterload (left ventricular developed pressure) from 66 to 97 mmHg produced by elevating aortic pressure caused an increase in peak dP/dt from 1,829 +/- 222 mmHg/s to 2,449 +/- 254 mmHg/s (p less than 0.001, n = 7), and a decrease in the mean systolic ejection rate from 2.12 +/- 0.36 ml/s to 1.95 +/- 0.33 ml/s (p less than 0.001). Studies using isolated rat papillary muscles ruled out the contribution of an increase in myocardial perfusion to the increase in peak dP/dt, since the maximum rate of rise in tension (dT/dt) increased with an increase in afterload during afterloaded isotonic contraction. Peak dP/dt showed a linear relationship to left ventricular developed pressure when the latter was increased by elevating the aortic reservoir and then clamping the aortic outflow tube (n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Activities of thymidylate synthetase and thymidine kinase in gastric cancer.

In a previous clinical study, sequential methotrexate and 5-fluorouracil has shown improved efficacy for treating advanced gastric cancer of the poorly differentiated type. In this study, we investigated whether difference in the levels of thymidylate synthetase (TS) and thymidine kinase (TK) activities in gastric cancer tissue account for selectivity of the treatment. Activity of TS was higher in 19 cases of the poorly differentiated type than in 16 cases of the well differentiated type (P < 0.02), whereas TK activity was lower in the poorly differentiated type than in the well differentiated type (P < 0.01). Thus, the TS/TK ratio was significantly higher in poorly differentiated gastric cancers than in well differentiated cancers (P < 0.001). These results suggest that a greater dependence upon the de novo pathway of pyrimidine synthesis in poorly differentiated gastric carcinomas may enhance the efficacy of sequential methotrexate and 5-fluorouracil treatment.

Adenocarcinoma↗
PubMed1992

Estimation of relative fecundity in Eimeria tenella strains by a mixed infection method.

The relative fecundity of populations of Eimeria tenella was estimated by means of mixed infection using electrophoretic variation of glucose-phosphate isomerases (GPIs) as a genetic marker. A decoquinate-resistant strain with GPI-9 isozyme (DR-NIAH), a decoquinate-sensitive one with GPI-1 (DS-Iwate), and three decoquinate-resistant lines (No. 3, 4, and 5) derived from cross-fertilization between DR-NIAH and DS-Iwate, were used. The GPI phenotypes of the No. 3 and No. 4 lines are GPI-9, and that of No. 5 is GPI-1. Mixed infection experiments were performed between DR-NIAH and DS-Iwate, No. 3 and No. 5, and No. 4 and No. 5. DR-NIAH was predominant over DS-Iwate in the mixed infection, whereas, in single infections, the total oocyst output of DR-NIAH was similar to or less than that of DS-Iwate. Among three lines, No. 4 was predominant over No. 5, and No. 5 was predominant over No. 3 in the mixed infection. Relative fecundity between No. 3 and No. 5 and their patterns of oocyst output in single infections were similar to those in the mixed infection. In contrast, No. 5 produced more oocysts than No. 4 in single infections, suggesting that the oocyst production in the mixed infection may be influenced by the mutual interference or competition between the populations of E. tenella in the chicken caeca.

Animals↗
PubMed1992

Carcinoid tumor of the middle ear containing serotonin and multiple peptide hormones. A case report and review of the pathology literature.

A 69-year-old man complaining of longstanding hearing loss and mild otorrhea was found to have a mass obliterating the external auditory canal and polypous tympanic mucosa with accompanying absence of the tympanic membrane and ossicular chain. Tumors excised from the external auditory canal and tympanum showed histologic features essentially characteristic of a carcinoid tumor: a ribbon or festoon arrangement of tumor cells, formation of anastomosing cords and glandular spaces, presence of numerous argyrophilic as well as argentaffin secretory granules within many of the tumor cells, and ultrastructural evidence of neurosecretory granules in the tumor cell cytoplasm. Immunohistochemically, the tumor was found to contain not only neuronal marker substances such as neuron-specific enolase, S-100 protein and chromogranin A, but also serotonin and multiple peptide hormones such as pancreatic polypeptide, glucagon, cholecystokinin and leucine-enkephalin. A review of the pathology of 17 previous cases of carcinoid of the middle ear suggested that this type of carcinoid may have a variegated hormone profile among carcinoids of foregut origin, and hormonally may resemble ileal carcinoid arising from the midgut, although their histogenetic origins may differ, because of frequent production of serotonin.

Aged↗
PubMed1992

Analysis of lymphoid follicles in liver of patients with chronic hepatitis C.

Using immunohistological methods, we studied the lymphoid follicles in liver biopsy specimens obtained from patients with chronic hepatitis C(CH-C) to determine whether they represented an autoimmune manifestation. In 84 specimens obtained by liver biopsy from 76 patients positive for C-100 antibody, we assessed the presence or absence of lymphoid follicles within the portal areas, and then compared the clinical and immunohistological profiles of the two groups defined on this basis. There were no significant differences in the serological and clinical profiles of the two groups, but the T4:T8 cell ratio within the portal areas differed significantly. A T4:T8 cell ratio > 1.0 was more common in the specimens containing lymphoid follicles. This finding resembled the distribution of T cell subpopulations in the portal areas of patients with autoimmune hepatitis, and suggested that lymphoid follicles may be worth investigating to elucidate the relationship between chronic hepatitis C and autoimmune hepatitis.

Autoimmune Diseases↗
PubMed1992

A case of malignant lymphoma accompanied by Klinefelter's syndrome.

A 66-year-old Japanese male with diffuse non-Hodgkin's lymphoma, of the pleomorphic type, complicated with Klinefelter's syndrome is reported. His phisique was characterized by a long arm span, disproportionately longer lower body dimensions and a small sized penis. He had no children. Chromosomal study revealed 47, XXY and hormonal quantification showed hypergonadtropic hypogonadism. Although chemotherapy was administered, his disease took a progressive course and he died. A discussion of chromosomal alteration and oncogenesis and review of the literature are included.

Aged↗
PubMed1992

Multiple endocrine neoplasia type 2A.

A 40-year-old woman was admitted with complaints of headache, palpitation and diaphoresis. She had undergone right hemithyroidectomy 12 years previously. Histological reexamination of the operative specimen revealed a medullary thyroid carcinoma. Abdominal ultrasonography, CT scan and angiography showed bilateral adrenal tumors. Serum catecholamine levels in both adrenal veins were high. Based on these data, bilateral adrenalectomy was performed. Histological examination confirmed the diagnosis of pheochromocytomas. After operation, serum calcitonin and urinary noradrenaline levels were still high. Further examination by 131I-metaiodobenzylguanidine (MIBG) scintigraphy is planned.

Adrenal Gland Neoplasms↗
PubMed1992

[Pulmonary arteriography and bronchial arteriography in pulmonary embolism].

Pulmonary arteriography is the most reliable technique for evaluation of pulmonary embolism and other vascular abnormalities. A definitive diagnosis of pulmonary embolism is made on the basis of direct angiographic signs of emboli of intravascular filling defect and vessel cut-off sign. To obtain these findings, pulmonary arteriography needs to be performed as soon as possible, and in acutely ill patients who are in shock and under consideration for thrombolytic therapy or emergency embolectomy, the study should be performed on an emergency basis. Digital subtraction pulmonary angiography may be an useful technique for massive pulmonary embolism, but it cannot exclude clinically important peripheral pulmonary embolism. Wedged pulmonary arteriography can demonstrate the direct signs of distal emboli, which are difficult to obtain by main pulmonary artery injection angiogram. In the chronic stage of pulmonary embolism, bronchial arteriogram shows collaterals to pulmonary arteries. This study may be useful in patients with chronic pulmonary embolism, especially when thromboembolectomy is planned.

Angiography, Digital Subtraction↗
PubMed1992

[The changes in molecular markers for hemostatic activation after t-PA therapy in case of pulmonary embolism].

We observed the changes of molecular markers for hemostatic activation in a patient with acute pulmonary embolism treated with 2 x 10(7) unit tissue plasminogen activator (t-PA). Blood samples were obtained before, just after, at 30 min, 1, 2, 6, and 24 hours after the infusion. Molecular markers included thrombin-antithrombin III complex (TAT), plasminogen-alpha 2 plasmin inhibitor complex (PIC), and thrombomodulin (TM). Marked elevation of TAT was observed from immediately after the t-PA infusion to 6 hours after, although it had been observed for only 1 hour in our previous report on the cases of acute myocardial infarction. PIC level was significantly increased during t-PA infusion but returned to almost baseline value 6 hours after the end of t-PA infusion. This finding was almost the same as the one previously reported concerning acute myocardial infarction cases. TM level increased throughout the evaluation, and remained so, even on the 7th day after t-PA infusion. Our present data revealed a clear difference between the reactive TAT increases after t-PA therapy in acute myocardial infarction cases and in acute pulmonary embolism cases. Our present data also revealed a prolonged elevation of TM during the acute period of pulmonary embolism. It is therefore necessary to keep an eye on the changes of molecular markers for hemostatic activation after t-PA therapy in acute pulmonary embolism.

Aged↗
PubMed1992

Contractile actions of endothelin-1 in isolated helical strips from rat pulmonary artery: potentiation of serotonin-induced contraction.

Endothelin-1 (ET-1) caused a concentration-dependent contraction of helical strips from rat pulmonary arteries. Removal of endothelial cells did not change the response to ET-1. ET-1 (10(-8) M) induced a small contraction of the arterial strips in the absence of extracellular Ca2+ (31.0% of the contraction in the presence of extracellular Ca2+). Pretreatment of pulmonary arterial strips with 6 x 10(-11) M ET-1 potentiated the serotonin-induced contraction (10(-7)-3 x 10(-6) M), but showed no significant effect on KCl-induced contraction. The ET-1-induced potentiation of the response to serotonin was prevented by nordihydroguaiaretic acid (3 x 10(-6) M), quinacrine (10(-6) M), and AA861 (10(-6) M), but not by indomethacin (10(-7) M) and baicalein (10(-6) M). These results suggest that ET-1 may cause pulmonary hypertension through a direct vasoconstrictor action and potentiation of serotonin-induced contraction, which may involve the 5-lipoxygenase pathway.

Animals↗
PubMed1992

[Cryosurgery for left atrial myxoma with coronary artery bypass grafting].

This is the first report of cryoblasion of atrial myxoma which was performed in conjunction with coronary artery bypass grafting. A 63-year-old man was admitted for left atrial tumor and ischemic heart disease. Following coronary artery bypass grafting and resection of left atrial myxoma, cryosurgery was carried out for the residual tumor on atrial septum and left atrial posterior wall. Ultrasonic cardiogram after 1 year revealed no signs of recurrence. Cryoablasion was effective in preventing the recurrence of atrial myxoma.

Coronary Artery Bypass↗
PubMed1992

[False aneurysm formation during the chronic phase of myocardial infarction at the margin of a previously-detected true aneurysm].

The patient was a 59-year-old man who had acute extensive anterior myocardial infarction in October, 1989. One month later, he was transferred to Kyoto University Hospital and underwent cardiac catheterization. Left ventricular aneurysm and significant stenosis in the proximal portion of the left anterior descending artery were documented. Because he experienced chest pain on slight exertion accompanied by a slight increase in the depth of the negative T wave on electrocardiogram, percutaneous transluminal coronary angioplasty (PTCA) was performed. Thereafter, chest pain disappeared, and the patient was discharged. Three months later, he was re-admitted to Kyoto University Hospital for a repeat cardiac catheterization after PTCA. PTCA site was found to be restenosed, and a small diverticulous aneurysm was found at the margin of the previously-detected ventricular aneurysm. As the diverticulous aneurysm was considered likely to precipitate the ventricular aneurysm into rupture, expeditious left ventricular aneurysmectomy was performed to prevent cardiac rupture. Ventricular aneurysms, common complications in myocardial infarction, are of two types, either true or false. Most aneurysms develop during the acute phase of myocardial infarction, and rupture of true aneurysms during the chronic phase of myocardial infarction rarely occurs. However, in the present case, a small diverticulous aneurysm, which was not demonstrated at the initial cardiac catheterization, developed during the chronic phase of myocardial infarction. Pathological examination revealed that the diverticulous aneurysm was a false aneurysm due to incomplete rupture. When the common pathogenesis of ventricular aneurysms in myocardial infarction is considered, the present report might represent an extraordinary rare case.(ABSTRACT TRUNCATED AT 250 WORDS)

Aneurysm, Ruptured↗