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Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 865 records · Page 48Linked to original sources
PubMed1990

Regional blood flow in transected rat spinal cord during hypothermia.

Regional blood flow (RBF) increases in the spinal cord and sciatic nerve of acutely hypothermic rats. To determine whether cord transection affects this response, we measured RBF in rat spinal cord and sciatic nerve 2 h after cord transection at vertebrae T8 (n = 18 rats) and T11 (n = 18 rats) using [14C]butanol distribution. Nine in each group were normothermic controls. In T11 transection-hypothermia (25-27 degrees C rectal temperature), RBF increased in the three rostral cord segments by 28-40% (P less than 0.05); caudally, cord RBF was depressed in two segments (P less than 0.05), unchanged in the other; RBF fell in nerve (P less than 0.05). In T8 transection-hypothermia, RBF was unchanged in the two rostral cord segments; caudally, RBF was depressed in one cord segment (P less than 0.05) and unchanged in the others; RBF was unchanged in nerve. We conclude that RBF does not rise in caudal spinal cord segments or in sciatic nerve during hypothermia in rats with prior spinal cord transection.

Animals↗
PubMed1990

Isolation of cytotoxic substance, kalafungin from an alkalophilic actinomycete, Nocardiopsis dassonvillei subsp. prasina.

An alkalophilic actinomycete, strain OPC-553 regarded as Nocardiopsis dassonvillei subsp. prasina, produced the cytotoxic substance, TS-1, which showed a marked inhibitory activity against L5178Y mouse leukemic cell in vitro. The cytotoxicity of TS-1 on this cell was very strong and its ID50 was 0.018 micrograms/ml. Through direct comparison of its spectral data with those of an authentic sample, TS-1 was identified as the antifungal antibiotic, kalafungin, already isolated from the culture broth of Streptomyces tanashiensis. However, the isolation of kalafungin from an alkalophilic actinomycete and its cytotoxicity are reported for the first time in this paper.

Actinomycetales↗
PubMed1990

Cardiac magnetic resonance imaging in evaluation of anatomical structure and function of the ventricles.

Cardiac magnetic resonance imaging (MRI) is being widely employed for evaluation of cardiovascular anatomies and functions. However, the indications for cardiac MRI to obtain information which cannot be obtained using other conventional methods have not yet been determined. To demonstrate of usefulness of MRI in delineating the apex of the left ventricle and free wall of the right ventricle, end-diastolic short axis MRI images were obtained in 20 patients with apical hypertrophy and in 9 normal volunteers. To compare the accuracy of estimations of left ventricular volumes obtained using the modified Simpson's method of MRI with that using the MRI area length method, 19 patients, in whom left ventriculography had been performed, were studied. The apex of the left ventricle was evaluated circumferentially and distribution of hypertrophied muscles was defined. Sixty-five percent of the length of the right ventricular free wall was clearly delineated. Correlation coefficients of the ejection fraction between MRI and angiography were 0.85 with the modified Simpson's method of MRI, and 0.62 with the area length method of MRI. Three themes were chosen to demonstrate good clinical indications for cardiac MRI.

Cardiac Volume↗
PubMed1990

Significance of left atrial pressure and left ventricular relaxation as determinants of left ventricular early diastolic filling flow in man.

We analyzed the relationships among parameters of left ventricular (LV) early diastolic filling flow (EDF) obtained with pulsed Doppler echocardiography, mean pulmonary wedge pressure (PCWP) and the time constant of LV pressure fall calculated by either Weiss' (Tw) or Thompson's (Tb) method. PCWP correlated with the peak velocity (R) (r = 0.537, p less than 0.05), acceleration (Ac) (r = 0.545, p less than 0.05) and deceleration (Dc) (r = 0.606, p less than 0.01) of LVEDF. In contrast, Tb correlated only with the time to the peak of LVEDF (TPF) (r = 0.487, p less than 0.05), and Tw did not correlate with the Doppler-derived indices significantly. After correcting for the effect of PCWP, significant partial correlations between R and Tw (r = -0.535, p less than 0.05), and between Ac and both Tw (r = -0.606, p less than 0.01) and Tb (r = -0.569, p less than 0.05) were found. Dc did not correlate with Tw or Tb. These results suggest that the level of left atrial pressure may mask the relationship between parameters of LVEDF and LV relaxation, and that the relations among these variables vary with individual indices of LVEDF.

Adult↗
PubMed1990

[Relationship between exercise-induced changes in serum and hepatic cholesterol metabolism in rats].

The purpose of the present study was to determine the effects of exercise training on serum cholesterol level and hepatic cholesterol metabolism in rats. Twenty-four male Wistar strain rats, aged 6 weeks, were assigned to one of three experimental groups; control (n = 8), exercised 20 minutes a day (E20, n = 8), and exercised 60 minutes a day (E60, n = 8). Rats were sacrificed after ten weeks exercise. The levels of serum total cholesterol and HDL-cholesterol in the group E20 and group E60 were lower than that of control, 8% and 24% (p less than 0.01) for the total cholesterol and 10% and 24% (p less than 0.05) for the HDL-cholesterol, respectively. The activity of HMG-CoA reductase in liver microsome was significantly higher in the group E60 than that of control. The hepatic microsomal HMG-CoA reductase activity was negatively related to serum total (r = -0.62, p less than 0.01) and HDL (r = -0.58, p less than 0.01) cholesterol levels. From these results, we concluded that the enhancement of the cholesterol metabolism in the liver by exercise is a major course of the exercise-induced change in serum cholesterol of Wistar rats.

Animals↗
PubMed1990

Primary pituitary carcinoma with spinal cord metastasis--case report.

The authors report a rare case of non-functioning pituitary carcinoma with spinal cord metastasis. A 37-year-old female presented with a 2-month history of right retro-orbital ache and vomiting. She had a pituitary adenoma removed 3 years prior to admission. Neuroradiologically, a mass lesion was demonstrated in the right middle cranial fossa. The tumor was removed through craniotomy and was histologically diagnosed as pituitary carcinoma. One week after the operation, tetraplegia developed and CT scans demonstrated a spinal canal lesion. Although the tumor was removed through C3-C7 laminectomies, she gradually deteriorated and died. At autopsy, a tumor was disclosed in the right temporal lobe and basal ganglia. Moreover, the tumor invaded into the middle cranial fossa and the parasellar region.

Adult↗
PubMed1990

Immunohistochemical studies of Vogt-Koyanagi-Harada disease with sunset sky fundus.

We studied Vogt-Koyanagi-Harada disease (VKH) with sunset sky fundus using histopathology and immunohistochemical methods. The materials examined were 4 eyes obtained at autopsy on two patients with VKH. The first patient died 32 months after the onset of VKH, and the other 7 years after onset. Histopathology of the eyes showed scattering infiltration of lymphocytes in the thickened choroid with a remarkable disappearance of choroidal melanocytes. T and B lymphocytes were identified by immunohistochemistry, using monoclonal antibodies. Approximately 70% of the lymphocytes were T cells. In the case 1 patient, the ratio of CD4+ to CD8+ T cells was 2 to 3. Thus, the evidence of T and B lymphocytes in these uveal tissues indicates that the inflammation remained active even at the convalescent stage.

Aged↗
PubMed1990

Severe hypersensitivity to mosquito bites associated with natural killer cell lymphocytosis.

A 2-year-old girl showed exaggerated skin reactions to mosquito bites and associated general symptoms, including a high temperature, lymphadenopathy, and hepatosplenomegaly. Peripheral blood lymphocytes contained a high percentage of CD2+, CD3-, CD4-, CD8-, CD11b+, CD16+, CD38+, CD56+, CD57-, and HLA-DR+ large granular lymphocytes that exhibited a marked natural killer cell activity. Immunohistochemically, biopsy specimens taken from the lesional skin demonstrated an infiltrate of the cells bearing the natural killer cell phenotype, indicating a role of these cells in the development of the abnormal skin reactions to mosquito bites and other systemic manifestations. Our case suggests that natural killer cell lymphocytosis may show severe hypersensitivity to mosquito bites as the most outstanding manifestation.

Animals↗
PubMed1990

[Immunohistochemical study of the surface membrane on a intra-ocular lens].

Surface membranes of intraocular lenses implanted in three rabbit, were studied immunohistochemically with anti-rabbit fibronectin serum and anti-rabbit whole serum antiserum. The specimens were embedded in an epoxy resin and cut at 1 micron. Before the immunostaining procedure, the sections were placed in a solution of saturated NaOH in absolute ethanol to remove the epoxy resin. Immunostaining procedure was performed by routine avidin-biotin-peroxidase technique. The surface membranes showed positive reactions against both anti-sera. These results indicated that the surface membrane of implanted intraocular lenses was composed of fibronectin with some other serum proteins.

Animals↗
PubMed1990

[Blood pressures at work, home and during sleep in patients with essential hypertension: analysis by ambulatory blood pressure monitoring].

Blood pressure (BP) recordings were obtained every 30 min using a noninvasive ambulatory BP recorder during 24 hours in 93 subjects with hypertension. Recordings were analyzed in four different situations: (1) annual check up at the health service center, (2) at work, (3) at home, and (4) during sleep. Subjects with BP higher than 160/95 mmHg in any of the three situations were defined as established hypertensive (n = 36); Subjects with 140-159/90-94 mmHg, as the borderline hypertensive (n = 32); and subjects with BP lower than 139/89 mmHg, as the normotensive (n = 25). Four successive systolic and diastolic BP values were averaged and served as 24-hour BP patterns. Systolic BP over 140 mmHg, diastolic BP over 90 mmHg and mean BP over 107 mmHg were defined as a s-hyperbaric index (s-HBI), d-HBI and m-HBI, respectively. The normotensive group showed a marked decrease of BP after recordings explained by the "white coat phenomenon". The 24-hour recordings in all the three groups showed the highest BP at work and the lowest during sleep. The situational BP changes were generally similar, but the established hypertensive group showed larger BP differences between work and home (SBP 8.8 +/- 9.0 mmHg, 7.8 +/- 8.3 mmHg). For differentiating the three groups, the hyperbaric index was better than the 24-hour average BP. The average home BP showed a good correlation with the 24-hour average BP [SBP: r = 0.94 (p less than 0.01), DBP: r = 0.85 (p less than 0.01)]. Especially, BPs recorded before sleep predicted well the 24-hour average BP. An average of multiple BP measurements before sleep is thought to represent a 24-hour average BP more closely than a conventionally used single recording at home or after awakening.

Adult↗
PubMed1990

[Paradoxical left ventricular blood flow during the isovolumic relaxation period in non-obstructive hypertrophic cardiomyopathy: Doppler and M-mode echocardiographic study].

The left ventricular blood flow pattern during the isovolumic relaxation period was investigated in 17 patients with apical hypertrophy (mean 54 +/- 8 years) and 30 with asymmetric septal hypertrophy without left ventricular outflow obstruction (mean 54 +/- 14 years). Thirty-five age-matched normal subjects served as controls (mean 51 +/- 10 years). All cases were examined by pulsed Doppler echocardiography simultaneously with phonocardiography. In all the control subjects, an apically-directed flow was observed, which occurred simultaneously with the onset of the second heart sound. In contrast, a basally-directed flow was detected during the isovolumic relaxation period in 13 patients (76%) with apical hypertrophy and in 28 (93%) with asymmetric septal hypertrophy. In these cases, an apically-directed flow was often observed before the second heart sound. Standard M-mode echocardiography revealed a significant increase in the left ventricular short-axis dimension at the base during the isovolumic period in patients with hypertrophic cardiomyopathy, while the normal controls showed no significant change. Moreover, peak velocity of the basally-directed flow correlated significantly with the rapidity of dilatation of the basal dimension (r = 0.61, p less than 0.01). Thus, this basally-directed blood flow in the left ventricle during the isovolumic relaxation period may be caused by the asynchronous left ventricular dilatation during the isovolumic period.

Adult↗
PubMed1990

[Flow cytometric cell cycle analysis of lymphocytes in patients with drug eruption].

DNA synthesis of lymphocytes was analyzed by flow cytometry in patients with drug eruption, eczema, viral eruption, and normal individuals. Lymphocytes were taken from the patients having fresh skin rash. In the patients with drug eruption, the percentages of lymphocytes in the G0G1 phase were lower and those in S + G2M phase were higher than the values in other groups, indicating the occurrence of blastogenic reaction. We considered that this method was helpful for diagnosis of drug eruption.

Adult↗
PubMed1990

Beta-adrenergic regulation of gastrin release from gastrinoma cells.

The effect of epinephrine on the plasma gastrin level was investigated in three patients with Zollinger-Ellison syndrome (ZES) and in 14 normal subjects. Two ZES patients had undergone total gastrectomy, and the third had undergone subtotal gastrectomy before our study. A significant increase in plasma gastrin, from 23 +/- 5 pg/ml to 53 +/- 20 pg/ml, in response to intravenous epinephrine (40 ng/kg.min), was observed in the normal subjects. This response was completely abolished by beta-blockade. In the ZES patients, epinephrine (40 ng/kg.min) also resulted in an increase in the plasma concentration of gastrin. The basal and maximum concentrations of gastrin were 580 and 1680 pg/ml in patient 1, 145000 and 320000 pg/ml in patient 2, and 200 and 1800 pg/ml in patient 3, respectively. beta-Adrenergic blockade suppressed the epinephrine-stimulated gastrin release in these patients as well. Graded intravenous doses of epinephrine given to the ZES patients resulted in elevation of the plasma gastrin in a dose-dependent manner. Insulin hypoglycemia caused an increase in both plasma epinephrine and plasma gastrin in ZES patients and normal subjects. A significant correlation between plasma gastrin and epinephrine during insulin hypoglycemia was observed in both groups. Exercise, with use of a bicycle ergometer, resulted in an increase in plasma epinephrine. An increase in plasma gastrin with exercise was observed in the ZES patients, and this was also suppressed by beta-blockade. The results suggest that gastrinoma cells, like normal G cells, are equipped with beta-adrenergic receptors that regulate gastrin release.

Adult↗
PubMed1990

[Results of the treatment of intracranial germ cell tumors].

Presented is a retrospective study of 20 patients with intracranial germ cell tumors who the authors have treated during past 10 years. The cases among these patients included thirteen germinomas, three teratomas, two embryonal carcinomas, and two malignant teratomas. A ventriculoperitoneal shunt was installed in 15 cass and the tumor was surgically removed in four cases. All cases were irradiated with 33 to 61 Gy; in 18 cases, more than half of the total dose was delivered to the whole brain, and in 9 cases, spinal irradiation was given because of a verified CSF dissemination. Chemotherapy was the regimen for four cases. The tumor responded to therapy in 16 (84%) of 19 evaluable cases. Overall, the median and five year survival were 102 months and 83%, respectively. The survival rate was found to vary between the benign group (germinoma, teratoma) and the malignant group (embryonal carcinoma, malignant teratoma, germinoma with STGC) (p less than 0.01).

Adolescent↗
PubMed1990

[Fundamental studies on the subrenal capsule assay as chemosensitivity test for nonsolid tumors].

Fundamental evaluation of the subrenal capsule assay (SRCA) method in nonsolid tumors was made, using two types of murine malignant ascites. Malignant ascites were obtained from mice bearing M-5076 ovarian reticular cell sarcoma or MH-134 hepatoma. These tumor cells were allowed to settle by standing at 4 degrees C to form a jelly-like clot. This clot was cut into fragments about 1mm3 in size and one of these fragments was mashed in trypan blue to estimate the viability grade of the implanted tumor cells. The rest of the fragments were implanted beneath the renal capsule of the mice. On the 6th day after implantation, the assay mice were killed, the increase in the size of the tumor was determined and histological examination was carried out. The results were as follows: (1) The clot was formed reproductively by allowing ascites to settle for one or two days and there was a high viability rate for the tumor cells: 79.9 +/- 11.0% of M-5076 and 90.1 +/- 5.9% of MH-134. (2) The ascites clot thus implanted grew rapidly in the control groups but growth was inhibited by chemotherapy: Tumors were reduced significantly (p less than 0.05-0.005) in the group treated with a single agent. This trend towards a suppressive effect of carcinocidal agents on the tumor growth was more conspicuous as a combination regimen was utilized, a combination of three agents producing the maximum effect. (3) The clot grew more quickly than the solid tumor in both the control and the treated groups. There was a high correlation (r = 0.93 in M-5076, and r = 0.64 in MH-134) between the growth rates of ascites and solid tumor in SRCA. (4) Histological examination revealed that viable tumor cells infiltrated widely under the renal capsule in both types of tumors. These results suggest that ascites and solid tumor are useful materials for the subrenal capsule assay method.

Animals↗
PubMed1990

MRSA meningitis in postoperative patients. Report of 4 cases.

Four cases of postoperative meningitis caused by methicillin-resistant Staphylococcus aureus (MRSA) are reported together with a review of the literature. These 4 cases were treated successfully by intravenous administration of minomycin, fosfomycin, and cefmetazole. Factors associated with the development of meningitis included multiple craniotomies, the presence of ventricular drainage or a ventriculo-peritoneal shunt, and irradiation.

Adult↗
PubMed1990

[Study on the frequency and clinical significance of positive RAST for mould allergen in asthmatic patients].

Recently, moulds are considered to be important allergens for bronchial asthma. To confirm this fact, 76 asthmatic patients (mean age 12.5, range 6-17 years) admitted to National Chubu Hospital were investigated for 16 different mould allergens by Pharmacia RAST RIA to measure specific-IgE for moulds. The results were as follows. 1) The frequency of positive RASTs (score greater than or equal to 2) varied from 4% to 21% depending on the allergen. Because 21 patients were RAST positive to one or more allergens, ultimately 26 patients (34%) appeared to be RAST positive to more than one of the 16 mould allergens. 2) According to the number of positive RASTs, the patients were divided into 3 groups, i.e. group 1 with more than five, group 2 with less than four and group 3 with zero. The ratio of patients with severe and moderate asthma to the total subjects was not significantly different between three groups before admission, but significantly high in group 1 and group 2 in order compared to groups 3 (chi 2(4)df = 18.81, p less than 0.005) one year after admission. This tendency was already apparent even one month after admission. 3) The frequency of positive RASTs for mould allergens was higher in patients with atopic dermatitis than in those without it. From these results, positive RAST for mould allergen seems to have considerable influence to intractable asthma and atopic dermatitis in young asthmatic patients.

Adolescent↗