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Biomedical subjects

S Takeuchi

Publications and source records attributed to S Takeuchi.

At least 433 records · Page 24Linked to original sources
PubMed1993

Endothelin-3-induced relaxation of rat thoracic aorta: a role for nitric oxide formation.

1. Endothelin-3 (ET-3) at concentrations below those which caused contraction (30 nM) elicited endothelium-dependent relaxation followed by rebound contraction in rat isolated thoracic aorta. 2. Endothelin-1 also relaxed the rat aorta with a similar potency. 3. The nitric oxide (NO) synthase inhibitor, NG-nitro L-arginine, the radical scavenger, haemoglobin and the soluble guanylate cyclase inhibitor, methylene blue, each inhibited the ET-3-induced relaxation. 4. The calmodulin inhibitor, calmidazolium, considerably attenuated the relaxation caused by ET-3 without affecting that to nitroprusside. 5. Concentrations of ET-3 that were necessary to induce the relaxation also caused concentration-dependent elevation of guanosine 3':5'-cyclic monophosphate (cyclic GMP) levels. 6. NG-nitro L-arginine, haemoglobin, methylene blue, calmidazolium and removal of the endothelium completely abolished ET-3-stimulated cyclic GMP production. 7. These results suggest that ET-3 triggers NO formation possibly via ETB receptors on the endothelium to activate soluble guanylate cyclase, which in turn stimulates cyclic GMP production and smooth muscle relaxation. The enzyme contributing to the NO formation may be of the calcium/calmodulin-dependent, constitutive type.

Acetylcholine↗
PubMed1993

[A clinical study of chronic lower respiratory tract infections with Pseudomonas aeruginosa by transtracheal aspiration].

We investigated the yearly changes of the incidence of Pseudomonas aeruginosa (P. aeruginosa) isolated from chronic lower respiratory tract infections (CLRTI), and also performed a clinical study on CLRTI with P. aeruginosa by transtracheal aspiration (TTA) to clarify the recent trend of P. aeruginosa infection in CLRTI and the predisposing clinical factors to the acute exacerbation. The isolation rate of P. aeruginosa among the total isolated bacteria in CLRTI between December 1978 and March 1983 was 8.4%, but it increased to 23.1% between April 1988 and March 1993. In 69 episodes (40 cases) of P. aeruginosa isolated from CLRTI between April 1983 and March 1993, monomicrobial infections of P. aeruginosa were 42 episodes (60.9%) and polymicrobial infections were 27 episodes (39.1%). When the diseases were classified into acute exacerbated and non-exacerbated phases, polymicrobial infections were seen more in the former phase, and the principal organisms detected with P. aeruginosa were Haemophilus influenzae and Streptococcus pneumoniae. In the acute exacerbated cases, predisposing conditions concerning the exacerbation were divided into four patterns: 1. polymicrobial infections with H. influenzae or S. pneumoniae, 2. after acute upper respiratory tract infections due to viral superinfection, 3. early phase from bacterial replacement by P. aeruginosa, 4. immunocompromised states such as adrenal corticosteroid administration or systemic underlying diseases. These results suggest that the importance of P. aeruginosa in CLRTI is increasing year by year and we must pay attention to the fact that P. aeruginosa alone may also cause acute exacerbation in the latter 2 patterns of the condition.

Adult↗
PubMed1993

[Clinical study of anaerobic respiratory infection].

This clinical study involved 35 cases, anaerobic bacteria were detected by TTA (transtracheal aspiration) or percutaneous lung aspiration, or pleural puncture. These cases were treated over the last 8 years in our department. There were 9 empyema, 9 pneumonitis, 5 lung abscess, 1 necrotizing pneumonia and 11 chronic lower airway infection. In 13 cases (37%), anaerobic bacteria alone were detected, whereas both anaerobic and aerobic bacteria were observed in the other 22 cases (63%). Of all bacteria detected. Bacteroids and Peptostreptococcus were the most common. With respect to host factors involved in the pathogenesis of pleural and parenchymal infection, aspiration was though to be a major trigger in only 11 out of the 24 cases (46%). The other 13 cases (54%) showed no evidence of aspiration, indicating that some other triggers was responsible. In further study, these 13 cases were found either to be heavy smokers with Brinkman index of more than 600, or to show sign of chronic lower airway infection. Both conditions were characterized by an inhibition of the mucociliary transport in the lower airway. Therefore, this study suggested that in the case without apparent aspiration the failure of local defense mechanisms in the airway, as a result of heavy smoking and/or chronic lower airway infection are involved in the pathogenesis of anaerobic respiratory infection.

Adult↗
PubMed1993

[Clinical study of acute bacterial bronchitis].

Eighty-two episodes (77 cases) in which any pathogens were isolated from transtracheal aspiration (TTA) and which satisfied the new clinical criteria of acute bacterial bronchitis were clinically evaluated. Major pathogens isolated from TTA included H. influenzae, S. pneumoniae and B. catarrhalis. Fever developed in 91.5% of the patients. Sputum volume averaged 16.3 +/- 14.9 ml per day. All the patients suffered from coughs, which were so severe as to disturb sleep in 8.5% of the patients. Inflammatory indices included WBC 9738.0 +/- 3158.5/microliter, CRP 10.1 +/- 7.9 mg/dl and ESR 69.0 +/- 38.8 mm/hr on average, PaO2 fell in most cases. Compared to the group of patients with acute bacterial bronchitis from which a single pathogen was isolated, the numbers of elderly patients and smokers were significantly more in the group of multiple pathogens isolated from TTA. Prior episodes related to the development of acute bacterial bronchitis were upper respiratory inflammation in 46.3% and undergoing bronchoscopy in 4.9% of the patients. Antibiotics therapy cured acute bacterial bronchitis in 96.3% of the patients. In spite of treatment, 3 patients developed pneumonia and died.

Acute Disease↗
PubMed1993

[Pneumonia due to respiratory syncytial virus diagnosed by transtracheal aspiration in an adult].

A healthy-looking 44-year-old female was admitted to our hospital complaining of fever and hemosputum. The chest roentgenogram on admission showed patchy infiltrates of the segment 3 and 8 of the right lung. Laboratory studies showed a leukocyte count of 9700/microliters, erythrocytes sedimentation rate of 55 mm/hour and C reactive protein of 8.7 mg/dl. The arterial PO2 was 71.9 torr while the patient was breathing room air. Transtracheal aspiration was performed on admission, and strains and culture for bacteria, acid fast bacilli, fungi and mycoplasma were negative. Respiratory syncytial virus was isolated from transtracheal aspirates. The RSV complement fixing antibody titers rose from 1:40 to 1:16. She became afebrile on the fourth day after admission and her chest roentgenogram improved gradually. RSV infection should be considered in the differential diagnosis of atypical adult pneumonias.

Adult↗
PubMed1993

[Effect of erythromycin on production of cytotoxin and attachment factors of bacteria].

We studied the effect of erythromycin (EM) on the attachment of Pseudomonas aeruginosa and Neisseria gonorrhoeae to HeLa and HT-177 cell and on cytotoxin production of P. aeruginosa. 1. EM inhibited attachment of these bacteria. 2. EM inhibited manifestation of the pili of these bacteria. 3. EM inhibited production of protein II, the second attachment factor of N. gonorrhoeae. 4. EM inhibited production of 66 K cytotoxin of P. aeruginosa. On the basis of these findings, it was suggested that EM might inhibit infection by repressing manifestation of the attachment factor and production of cytotoxin of the bacteria.

Bacterial Adhesion↗
PubMed1993

[Determination of neutrophil function in the respiratory infection by chemiluminescence (CL). I: Change in neutrophil's CL by chemotherapy against the bacterial pneumonia].

We measured neutrophil's CL (CL-index) in 12 patients of the bacterial pneumonia three times per each case: before, during and after chemotherapy. Before the initiation of chemotherapy. CL-index in the six patients remained higher than that in healthy controls, while the remaining six showed lower levels of CL-index compared to the controls. In the 11 cases, their CL-indexes fell to levels lower than those obtained before treatment. Additionally, in the 11 cases their CL-indexes increased after the termination of chemotherapy. Furthermore, in the nine cases the product of the neutrophil number and CL-index was decreased by chemotherapy, and the decrease in the product correlated with improvement in their clinical conditions.

Adolescent↗
PubMed1993

Atypical beta-adrenoceptor- (beta 3-adrenoceptor) mediated relaxation of canine isolated bronchial smooth muscle.

To determine whether atypical beta-adrenoceptors (beta 3-adrenoceptors) exist in the airway smooth muscle, we studied isolated bronchial segments from dogs under isometric conditions in vitro. Addition of beta-adrenoceptor agonists produced a concentration-dependent relaxation of tissues precontracted with 10(-5) M acetylcholine, rank-order potency being isoproterenol (1) > or = salbutamol (0.95) > or = BRL 37344, a beta 3-selective adrenoceptor agonist (0.83) > norepinephrine (0.10). Under the condition that alpha- and beta 1-adrenoceptors had been blocked, the relaxant response to salbutamol was competitively antagonized by the beta 2-adrenoceptor antagonist ICI 118551 and the pA2 was 7.01 +/- 0.25 (SE), whereas the response to BRL 37344 was resistant, with an apparent pA2 of 5.66. However, cyanopindolol, an antagonist for atypical beta-adrenoceptors, antagonized the BRL-induced relaxation in a competitive manner, with a pA2 of 6.74 +/- 0.11. This pA2 was lower than that when salbutamol was used as an agonist (P < 0.05). Intracellular adenosine 3',5'-cyclic monophosphate (cAMP) levels were increased by BRL 37344 in a concentration-dependent fashion. These results suggest that beta 3-adrenoceptors may exist in canine bronchial smooth muscle and that the stimulation of this type of receptor causes a bronchodilation through a cAMP-dependent pathway.

Acetylcholine↗
PubMed1993

[Age-related alterations in the mechanism of renovascular contractility in patients with essential hypertension].

Systemic hemodynamics and renal blood flow (RBF) were studied before and during isometric exercise (IE) in 48 hypertensive patients. Of the 48 hypertensives, 21 were unmedicated and the remaining 27 patients were given one of the following drugs for 3 days prior to the study: 15 patients were treated with Enalapril (5 mg/day) and 12 patients were treated with Bunazosin (2 mg/day). Cardiac output (CO) and RBF were measured simultaneously with two different thermodilutional catheters. To elucidate the influence of aging on the renovascular response to IE, each group was divided into younger (age > 50) and older (age > or = 50) subgroups. RBF decreased and calculated renovascular resistance (RVR) increased significantly during IE in the unmedicated group, but showed no difference in the degree of changes in these parameters between the younger and older subgroups. In the Bunazosin group, RBF and RVR did not change during exercise in either subgroups. In the Enalapril group, RBF did not change in either subgroup, and RVR increased significantly in the younger subgroup, but was unchanged in the older subgroup. There was a negative linear relationship between delta RVRI (change of RVR corrected by body surface area) and age (y = -0.15x + 9.7, r = -0.59: p < 0.05). Plasma norepinephrine increased after IE, but these changes were not significant in all 3 groups. These data suggest that the enhanced renovascular contractility during IE is accomplished mainly through alpha 1-adrenoceptor, and the responsiveness of alpha 1-adrenoceptor may decrease with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Influence to organs by ten weeks tail suspension.

The subject of atrophy has been the focus of interest for morphologists as well as the scientist in the space medicine. Muscle atrophy was noted to be some influence of microgravity in the space. Using tail suspension techniques, we have studied the influence of gravity to rats. In the present study, we tried to study the influence of the long term microgravity, ten weeks tail suspension.

Adrenal Glands↗
PubMed1993

Relationship between hind-limb muscle atrophy and serum enzymes in tail suspended rats.

Many studies on the effects of gravity have been reported using animals or human being since the gravity influences the biological body in space. Especially suspension techniques for rat have been used as a microgravity simulation. This study is a report on the relation between serum enzymes such as CK and muscle atrophy, caused by tail suspension in rats.

Alanine Transaminase↗
PubMed1993

Effect of metoclopramide on muscle sympathetic nerve activity in humans.

For determining the effect of the activation of the central cholinergic system on the sympathetic nervous system, we measured muscle sympathetic nerve activity (MSNA) together with heart rate and blood pressure before and after an intravenous injection of metoclopramide. Immediately after metoclopramide injection, short-term increases in MSNA and heart rate followed a transient decrease in blood pressure, suggesting that increased sympathetic nerve activity may result from the unloading of arterial baroreceptors. Approximately 7 min after injection, MSNA and heart rate were again notably increased, followed by an increase in blood pressure. This late increase in MSNA may result from central activation of the sympathetic nervous system, but not as a result of the unloading of arterial baroreceptors. The results of this study suggest that metoclopramide activates the sympathetic nervous system by mediating the central cholinergic system in humans.

Adult↗
PubMed1993

Effect of L-dopa on human muscle sympathetic nerve activity.

This study was undertaken to clarify the mechanism of orthostatic hypotension, one of the side effects frequently encountered after administration of levodopa (L-dopa). Muscle sympathetic nerve activity (MSNA) was measured concomitantly with blood pressure (BP), heart rate (HR) and calf blood flow (calf BF). The responses of these variables to head-up tilting (HUT) were analyzed before and after intravenous administration of L-dopa (50 mg) in eight healthy subjects. L-dopa induced significant increases in MSNA, with concomitant decreases in BP and no changes in calf BF in the supine position. At each angle of HUT, both MSNA and the calf BF increased, following administration of L-dopa. The pattern of MSNA changes was dissociated from that of the calf BF under the influence of L-dopa. These results suggest that peripheral, rather than central, mechanisms are involved in L-dopa-induced orthostatic hypotension.

Adult↗
PubMed1993

[A comparative study among ftorafur, ftorafur plus tamoxifen, and tamoxifen in adjuvant therapy for breast cancer. The Chubu Cooperative Study Group of Adjuvant Chemoendocrine Therapy for Breast Cancer, Japan].

A randomized study assessing the efficacy of three treatment of ftorafur (FT), ftorafur plus Tamoxifen (TAM), and Tamoxifen in patients diagnosed as having stage II (N1b) or stage III breast cancer was carried out at 90 institutions in the Chubu district of Japan. After 10 mg of MMC administration on the day of surgery and the next day, patients were allocated to one of three treatments: FT 600 mg/day for 2 years, FT 600 mg/day plus TAM 20 mg/day for 2 years, or TAM 20 mg/day for 2 years. A total of 647 cases were analyzed. No significant differences were observed in the 5-year disease-free survival rates or in the 5-year survival rates. In the stratified analysis, however, a beneficial effect of adding FT to TAM was observed in the patients with ER-positive tumors in the 5-year survival rate, and FT plus TAM treatment was favorable compared with the other two treatments for postmenopausal patients with ER-positive tumors.

Adult↗
PubMed1993

[Effects of ascorbic acid on trace element metabolism in the choroid-retina of streptozotocin-induced diabetic guinea pigs].

In order to investigate the effect of ascorbic acid on trace element metabolism in the choroid-retina, experimental diabetes mellitus was induced in Hartley guinea pigs with intraperitoneal injection of streptozotocin. After 4 weeks, ascorbic acid-deficient feed was given for 3 weeks. Trace elements of the choroid-retina were measured with inductively-coupled plasma emission spectrometry. The activity of superoxide dismutase and lipid peroxide content also were measured. The results indicated that zinc and magnesium increased in diabetes mellitus. However, with ascorbic acid deficiency in diabetes mellitus, zinc and magnesium significantly decreased. On the other hand, the activity of superoxide dismutase showed no change between either condition and lipid peroxide content decreased under ascorbic acid deficiency in diabetes mellitus. These findings suggested that ascorbic acid played an important role in chorioretinal damage of diabetes mellitus. However, it was also suggested that lipid peroxide has little influence on the choroid-retina under these conditions.

Animals↗
PubMed1993

[Morphological study on edentulous mandibula].

For the purpose of studying morphology of edentulous mandibula, not only the bone change of edentulous alveolar part, but the whole morphological change of edentulous mandibula was examined. Thirty-three edentulous mandibulae that have no sockets owing to the bone absorption of alveolar ridge and eighty dentulous mandibulae that possess no missing teeth except wisdom teeth were measured and compared. The authors obtained the following results concerning the morphological change of edentulous mandibula: 1. Although the body height was significantly low on account of bone absorption at the alveolar ridge, bone absorption at base of mandibula was not much observed. 2. Both condylar process height and coronoid process height were significantly low. 3. Mandibular angle of edentulous mandibular was greater. 4. In dentulous mandibula a negative correlation between mandibular angle and condylar process height, coronoid process height was found. A correlation between mandibular angle and the difference of total mandibular length and body length was observed. A great mandibular angle was found because it seems that the bone deposition was less at the inferior and posterior margin of mandibular angle part. 5. It seems that bone absorption at inferior and posterior margin of edentulous mandibular angle part was due to less bone deposition. Because a bite force decreased for missing teeth.

Adolescent↗