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K Takagi

Publications and source records attributed to K Takagi.

At least 361 records · Page 20Linked to original sources
PubMed1994

Noninvasive measurement of left ventricular myocardial elasticity.

We examined Advani and Lee's equation (ALeq) and a dimension analysis-derived equation (DAeq), both of which treat vibration of the elastic spherical shell and are able to estimate elasticity of the shell noninvasively when the sizes and eigen-frequency are provided. We confirmed that ALeq was numerically identical to DAeq and that both equations gave the precise elasticity of the silicone shell. Then we estimated left ventricular (LV) myocardial elasticity noninvasively at the moment of the first heart sound emission (1HS) in 25 healthy subjects and 14 hypertrophic cardiomyopathy (HCM) patients, based on the LV eigen-frequency detected by an intraesophageal miniature vibration sensor. HCM patients had a higher mean value of LV myocardial elasticity at 1HS than healthy subjects [102.3 +/- 33.4 vs. 70.7 +/- 24.4 kPa, P < 0.01 (Pa = N/m2 = 10 dyn/cm2)]. We thereby demonstrated the possibility of a noninvasive estimate of myocardial elasticity.

Adult↗
PubMed1994

Effect of hyperthermia on glutamate release in ischemic penumbra after middle cerebral artery occlusion in rats.

Using microdialysis, we investigated the effect of hyperthermia on glutamate release in penumbral cortex of rats with 2 h of either normothermic (37 degrees C) or hyperthermic (39 degrees C) middle cerebral artery (MCA) occlusion. Penumbral blood flow (CBF) was measured by laser-Doppler flowmetry. CBF values (expressed as % preischemic values) in normothermic and hyperthermic groups were 24 +/- 11 (SD) and 24 +/- 16%, respectively, during ischemia and 102 +/- 81 and 147 +/- 79% during recirculation. Average extracellular glutamate in the hyperthermic group increased from a baseline of 7 +/- 2 microM to a peak of 217 +/- 184 microM at 10-20 min after onset of ischemia but returned to near baseline after 60 min. Glutamate in the normothermic group increased from 4 +/- 2 microM to a peak of 26 +/- 17 microM at 10-20 min after MCA occlusion but fell to near-baseline before recirculation. Thus reuptake systems appeared to remain functional in ischemic penumbra, even during hyperthermia. Ischemic glutamate release was significantly higher in hyperthermic than in normothermic rats: average values of individual rats' peak levels were 251 +/- 221 microM and 37 +/- 34 microM, respectively. The ischemic CBF threshold value for glutamate release was 33% of control in the normothermic group but 61% in the hyperthermic group.

Analysis of Variance↗
PubMed1994

The effect of ritanserin, a 5-HT2 receptor antagonist, on ischemic cerebral blood flow and infarct volume in rat middle cerebral artery occlusion.

BACKGROUND AND PURPOSE: In a previous study from our laboratory, ritanserin, a specific 5-HT2 serotonin receptor antagonist, reduced ischemic damage in the setting of transient global ischemia. In this study, we examined the effect of ritanserin on ischemic cerebral blood flow, systemic blood pressure, and infarct volume in the model of permanent focal ischemia with brain temperature controlled at 35.0 degrees C to 36.0 degrees C. METHODS: Thirty-seven male Sprague-Dawley rats were used. The right middle cerebral artery was permanently occluded. Ritanserin (8 mg/kg) or vehicle was continuously administered intravenously for 90 minutes starting 10 minutes after middle cerebral artery occlusion. Cerebral blood flow was monitored by laser Doppler flowmetry in the ischemic cortex before and for 2 hours after arterial occlusion. Brains were perfusion-fixed 3 days later, and infarct volumes were measured. RESULTS: Mean arterial blood pressure was not affected by treatment. In the vehicle and ritanserin groups, mean ischemic cerebral blood flow (percent of preischemic values) was 34.6 +/- 14.7% (mean +/- SD) and 26.6 +/- 15.0%, respectively. Hemispheric infarct volumes were 119.3 +/- 49.4 mm3 and 136.6 +/- 49.6 mm3, respectively. No significant differences were recognized. CONCLUSIONS: Intravenous administration of ritanserin did not affect mean arterial blood pressure or cerebral blood flow in the ischemic region during the acute phase of ischemia. No protective effect of ritanserin was apparent in the setting of permanent focal ischemia when treatment was begun shortly after the onset of ischemia.

Animals↗
PubMed1994

Beta-adrenergic agonists regulate KCa channels in airway smooth muscle by cAMP-dependent and -independent mechanisms.

Stimulation of calcium-activated potassium (KCa) channels in airway smooth muscle cells by phosphorylation-dependent and membrane-delimited, G protein actions has been reported (Kume, H. A. Takai, H. Tokuno, and T. Tomita. 1989. Nature [Lond.]. 341:152-154; Kume, H., M. P. Graziano, and M. I. Kotlikoff. 1992. Proc. Natl. Acad. Sci. USA. 89:11051-11055). We show that beta-adrenergic receptor/channel coupling is not affected by inhibition of endogenous ATP, and that activation of KCa channels is stimulated by both alpha S and cAMP-dependent protein kinase (PKA). PKA stimulated channel activity in a dose-dependent fashion with an EC50 of 0.12 U/ml and maximum stimulation of 7.38 +/- 2.04-fold. Application of alpha S to patches near maximally stimulated by PKA significantly increased channel activity to 15.1 +/- 3.65-fold above baseline, providing further evidence for dual regulatory mechanisms and suggesting that the stimulatory actions are independent. Analysis of channel open-time kinetics indicated that isoproterenol and alpha S stimulation of channel activity primarily increased the proportion of longer duration events, whereas PKA stimulation had little effect on the proportion of short and long duration events, but resulted in a significant increase in the duration of the long open-state. cAMP formation during equivalent relaxation of precontracted muscle strips by isoproterenol and forskolin resulted in significantly less cAMP formation by isoproterenol than by forskolin, suggesting that the degree of activation of PKA is not the only determinant of tissue relaxation. We conclude that beta-adrenergic stimulation of KCa channel activity and relaxation of tone in airway smooth muscle occurs, in part, by means independent of cyclic AMP formation.

Adenylyl Imidodiphosphate↗
PubMed1994

Synergistic enhancement of nitrite on lysophospholipid-mediated cytolysis.

Nitrogen oxide, which is produced by activated macrophages, has been demonstrated to possess anti-tumor activity. We report herein the synergistic effect of sodium nitrite (NO2-) and/or sodium nitroprusside (SNP) on lysophospholipid (LysoPL)-mediated cytolysis. The incubation of 51Cr-labeled mouse melanoma (B16) cells with NO2- alone for 3 h at 37 degrees C did not induce cytolysis. On the other hand, NO2- significantly enhanced the cytolysis of B16 cells in the presence of lysophosphatidylcholine (LysoPC; 2.0 microM). A similar effect of NO2- on B16-cytolysis was also observed in the presence of 1-O-alkyl-sn-glycero-3-phosphocholine (LysoPAF). In addition, SNP (0.05-0.5 mM) synergistically enhanced B16-cytolysis in the presence of LysoPC. However, nitrate had no effect on the cytolysis of B16 cells treated with LysoPC. Furthermore, NO2- synergistically enhanced the hemolysis of sheep erythrocytes in the presence of LysoPC, but not in the presence of an anti-sheep erythrocyte antibody and complement. These findings suggest that NO2- directly affects membrane damage in the presence of LysoPL.

Animals↗
PubMed1994

Serum levels of soluble IL-2R, IL-4, and soluble Fc epsilon RII in adult bronchial asthma.

Examination was made of the serum levels of interleukin 4 (IL-4), soluble Fc epsilon RII (sFc epsilon RII), and soluble interleukin 2 receptor (sIL-2R) in 77 adult patients with bronchial asthma. All the patients had mild to moderate asthma and their symptoms were well controlled. The results were compared with values for 75 control subjects to clarify the involvement of these factors in the pathogenesis of bronchial asthma. Serum sIL-2R was elevated in asthmatics compared with control subjects (459.0 +/- 30.4 U/ml vs 251.5 +/- 10.0 U/ml; p < 0.001). The IL-4 and sFc epsilon RII levels were also elevated beyond those in the controls (IL-4: 1.89 +/- 0.13 pg/ml vs 1.08 +/- 0.15 pg/ml; p < 0.001) (sFc epsilon RII: 313.2 +/- 18.8 U/ml vs 228.8 +/- 6.7 U/ml, p < 0.001). A weak but significant correlation was observed between sIL-2R and sFc epsilon RII (r = 0.46, p < 0.001). Correlation among other parameters was not found. The patients were divided into atopic and nonatopic groups, based on the presence or absence of positive reaction to skin prick tests using extracts of common aeroallergens and positive specific IgE against house dust mite (Dermatophagoides pteronyssinus [Dp]). Mean IL-4 in the atopic group, with positive skin reaction and > 0.7 kU/L specific IgE against Dp was significantly elevated compared with the nonatopic group (2.35 +/- 0.26 pg/ml vs 1.56 +/- 0.12 pg/ml; p < 0.005). Such differences could not be detected in sIL-2R, sFc epsilon RII levels among the two groups. No significant correlation could be found among IL-4, sFc epsilon RII, and total IgE level. The activation of T cells and B cells would thus appear essential to the pathogenesis of bronchial asthma and the hypothesis that atopic status is associated with the preferential activation of TH2 cells which selectively produce IL-4 could be supported. The regulatory mechanism of IgE synthesis would not appear to be the only responsible factor.

Adult↗
PubMed1994

3 beta-Hydroxysteroid dehydrogenase activity and gestagen concentrations in bovine cotyledons and caruncles during gestation and parturition.

3 beta-Hydroxysteroid dehydrogenase (3 beta-HSD) activity in bovine cotyledons was much higher than in caruncles throughout the gestation period. The activity of this enzyme in cotyledons increased greatly to 150.6 +/- 5.8 pmol min-1 mg-1 protein during the seventh month of gestation, reached a peak of 221.0 +/- 34.9 pmol min-1 mg-1 protein during the eighth month, and decreased at parturition. Progesterone and 20 alpha-hydroxyprogesterone concentrations in cotyledons also increased sharply to 2.69 +/- 0.30 and 2.15 +/- 0.42 ng mg-1 protein, respectively, during the seventh month of gestation, reaching peaks of 2.86 +/- 0.47 and 2.51 +/- 0.36 ng mg-1 protein, respectively, during the eighth month and decreasing at parturition, in a manner similar to the activity of 3 beta-hydroxysteroid dehydrogenase. The fluctuation of 17 alpha-hydroxyprogesterone concentration in cotyledons was different from that of progesterone and 20 alpha-hydroxyprogesterone. These findings indicate that the activity of 3 beta-hydroxysteroid dehydrogenase in the placenta is enhanced during the third trimester, and progesterone synthesized in the cotyledons is converted concurrently to 20 alpha-hydroxyprogesterone before progesterone is transferred to the fetal blood.

17-alpha-Hydroxyprogesterone↗
PubMed1994

Lymphoid interstitial pneumonia as a pulmonary lesion of idiopathic plasmacytic lymphadenopathy with hyperimmunoglobulinemia.

A case of idiopathic plasmacytic lymphadenopathy with hyperimmunoglobulinemia is reported. A 71-year-old man was admitted to the hospital because of the abnormal shadow on chest roentgenogram. Chest X-ray taken on admission showed remarkable diffuse infiltration and pleural thickening. Laboratory examinations revealed an elevated total protein level of 10.1 g/dl, and a gammaglobulin level of 7.0 g/dl including 6,790 mg/dl IgG. Mediastinal lymphadenopathy was observed on a chest CT. The patient underwent open lung biopsy. Heavy infiltration of lymphocytes and plasma cells were seen in the moderately fibrotic pulmonary interstitium. LIP was diagnosed. Lymph node biopsy was also performed. Follicular hyperplasia with prominent germinal centers and plasma cell proliferation in the interfollicular area were seen. Treatment with prednisolone resulted in an improvement in the chest X-ray findings, as well as a diminished polyclonal hypergammaglobulin level.

Aged↗
PubMed1994

Development of a neutralizing monoclonal antibody against rabbit IL-1 receptor antagonist and utilization for ELISA and measurement of masked IL-1 activity in biological materials.

We developed a monoclonal antibody with neutralizing activity against the rabbit IL-1 receptor antagonist (IL-1ra) and a sandwich ELISA for rabbit IL-1ra. Using this ELISA, we measured IL-1ra contents in inflammatory exudate cells and culture supernatants of LPS-stimulated macrophages. The production of IL-1ra occurred rapidly after the onset of inflammation in vivo and after stimulation of macrophages in vitro and was sustained for a long period. The time interval for detection of IL-1 activity overlapped with the above mentioned period of IL-1ra production. In the presence of this neutralizing monoclonal IgG, the effect of IL-1ra in these biological specimens was nil and heretofore unrecognized IL-1 activity in the samples was measurable; the rate of this increment in activity ranging between 1.5- and 4.8-fold. We conclude that underestimations of IL-1 activity have been made and previously reported results on IL-1 activities in many biological materials have to be re-examined.

Animals↗
PubMed1994

Reduction of the severity of bronchial hyperresponsiveness by the novel leukotriene antagonist 4-oxo-8-[4-(4-phenyl-butoxy)benzoylamino]-2- (tetrazol-5-yl)-4H-1-benzopyran hemihydrate.

There is much evidence that the cysteinyl-leukotrienes (C-LTs) are important in the pathogenesis of asthma. The clinical effect of a new leukotriene antagonist, ONO 1078 (4-oxo-8-[4-phenylbutoxy)benzoylamino]-2-(tetrazol-5-yl)-4H- 1-benzopyran hemihydrate, CAS 103177-37-3) on symptoms, pulmonary lung function and bronchial hyperresponsiveness was evaluated in patients with bronchial asthma. Eleven patients were treated for 24 weeks with 450 mg of ONO 1078 twice daily. The score of asthma symptom severity and the number of inhaled procaterol were significantly reduced after 2 weeks of ONO 1078 treatment and remained decreased for another 22 weeks. Their FEV1 and PC20 to histamine significantly improved 12 and 24 weeks after ONO 1078 treatment. The effectiveness of ONO 1078 suggests that the C-LTs play an important role in the pathogenesis of asthma. ONO 1078 might help to favorably modify the pathophysiologic condition in patients with bronchial asthma.

Adult↗
PubMed1994

Histamine release induced by pituitary adenylate cyclase activating polypeptide from rat peritoneal mast cells.

Pituitary adenylate cyclase activating polypeptide 38 (PACAP 38) and its fragments PACAP 27, PACAP 16-38, PACAP 28-38, PACAP 31-38 were compared for their histamine releasing effects on rat peritoneal mast cells. PACAP 38 and PACAP 16-38 were the most active peptides, followed by PACAP 27. PACAP 38 and PACAP 16-38 dose-dependently increased histamine release at a concentration of 1 x 10(-8) mol/l or higher, and these releasing activities were more than 100 times more potent than that of substance P. Extracellular calcium inhibited the substance P-induced histamine release. In contrast, PACAP 38- and PACAP 27-induced histamine releases were hardly inhibited by extracellular calcium.

Animals↗
PubMed1994

[Thoracoscopic anatomy, significance of pathologic findings in thoracoscopic open lung biopsy, and pleural mesothelioma].

To better understand diseases of the thoracic space, pathologic findings of thoracoscopic open lung biopsy are described based on thoracoscopic anatomy and pleural mesothelioma. A positive colloidal iron stain in the plasma membrane of the mesothelial cells indicates the presence of hyaluronic acid, which appeared to decrease the friction between the lung and thoracic cavity. Excess fluid in the pleural cavity was removed from specific sites in the parietal pleura with stomas. We evaluated the pathologic features of 57 video-thoracoscopic open lung biopsies. Specific diagnoses were established in 89%, and of these half were pneumothorax. Nonspecific pathologic changes were found in 11%, of which interstitial pneumonia was the most common. This procedure is useful in taking a large number of specimens for diagnosis, and to evaluate the degree and progress of fibrosis. The differential diagnosis of mesothelioma from pulmonary adenocarcinoma, reactive mesothelial hyperplasia, and sarcoma of the pleura are described. Also, to understand mutations of the p53 tumor-suppressor gene in mesothelioma, mesothelial lesions were studied with immunostaining for p53 antibody (DO-7) and with in situ hybridization for p53 mRNA. In immunohistochemical staining for DO-7, all reactive mesothelial cells were positive, and 75% of mesotheliomas including epithelial, biphasic, and sarcomatous types were positive, and 75% of mesotheliomas including epithelial, biphasic, and sarcomatous types were positive. mRNA for p53 was expressed in all reactive mesothelial cells, and in 55% of allmesotheliomas.

Biopsy↗
PubMed1994

[A case of Castleman's disease that recurred nine years after initial surgical removal].

Castleman's disease (CD) is a lymphoproliferative disorder with resemblance in histopathology of thymoma. Here we describe a 48-year-old man with bloody sputum and a mass lesion of the right hilum on chest roentgenogram. He had undergone an incomplete surgical removal of a mediastinal tumor nine years earlier, which proved to be CD with characteristics of hyaline-vascular type pathology. The regrown mass lesion as well as the right upper and middle lobes were removed surgically. Histological examination of the tumor specimen revealed characteristics of hyaline-vascular type CD which were nearly identical to those of the tumor removed nine years earlier. Recurrence of CD as observed in the present report is very uncommon, since only 5 cases, including this one, have been reported. We suggest that in CD the primary tumor as well as regional lymph nodes should be completely removed, and the patients should be kept under long-term postoperative observation to check for recurrence.

Castleman Disease↗
PubMed1994

[Spontaneous regression of lumbar hernia of the nucleus pulposus. Follow-up study of 4 cases by repeated magnetic resonance imaging].

INTRODUCTION: As yet there have been no consistent magnetic resonance (MR) imaging studies on spontaneous regression of herniated lumbar nucleus pulposus (HNP). We present four patients in whom follow-up MRI images demonstrated spontaneous regression or complete disappearance of a herniated lumbar nucleus pulposus. One patient presented with a large extruded type, and the rest had the sequestrated type. All patients made evolved favorably with conservative therapy. RESULTS: Follow-up MRI images revealed a remarkable regression of the HNP in the extrusion case and complete disappearance in the sequestration cases. In the extrusion case, follow-up MRI images showed rapid shrinkage of the portion extruded into the epidural space. In the sequestration cases, MR images with Gadolinium DTPA (enhanced MR images) showed that the enhanced lesion around the HNP had reduced its size as the HNP diminished. Final MR images could not detect the HNP in any view of the spinal canal. CONCLUSION: We therefore concluded that the regression of HNP in MR images might have been due more to resorption than to dehydration.

Adult↗
PubMed1994

Giant cell tumor of bone: analysis of proliferative cells by double-labeling immunohistochemistry with anti-proliferating cell nuclear antigen antibody and culture procedure.

Giant cell tumor of bone (GCT) consists of multinucleated giant cells, fibroblast-like cells, and macrophage-like cells, but what constitutes the principal neoplastic cells and their histogenesis remains controversial. Proliferating cells in GCT have been immunophenotypically characterized with the cell cycle-related antigen proliferating cell nuclear antigen (PCNA). In seven cases, PCNA monoclonal antibody was applied by double-labeling immunohistochemical methods together with other cell-specific monoclonal antibodies. Many proliferating PCNA-positive cells were found in the vimentin-positive fibroblast-like cells, while almost all macrophage-like cells were negative for PCNA. The study of cultured cells showed that the fibroblast-like spindle-shaped cells were a neoplastic element. In addition, osteoclast-like cells were detected in co-culture systems of cells cultured from GCT with spleen cells. These studies support the concept that GCT is seen as a neoplasm of fibroblast-like cells with a strong reactive infiltration of cells from the mononuclear phagocyte system.

Antibodies, Monoclonal↗
PubMed1994

Parental origin of 11p15 deletions in human lung cancer.

Frequent occurrence of 11p deletions has been reported for diverse types of human cancers including lung cancers and Wilms' tumors. In contrast to the well documented identification of preferential retention of the paternal allele in Wilms' tumors, no data have hitherto been available for cancers of adults. Taking advantage of the paternal allele-specific expression of IGF2 in the normal lung, we examined 79 lung cancer cases to investigate allelic loss at 11p15 and the parental origin of the retained alleles. While 11 of 36 (31%) informative lung cancer cases exhibited 11p15 deletions, only seven of these (64%) retained the paternal allele in tumors (P = 0.274), showing a contrast to the strong paternal bias in childhood tumors. Our strategy eliminates the need for parental DNAs for the determination and should be applicable to other adulthood tumors carrying 11p deletions such as breast and bladder cancers.

Adult↗