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T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 883 records · Page 49Linked to original sources
PubMed1990

[Allergenicity of the osmophilic fungus Aspergillus restrictus evaluated by skin prick test and radioallergosorbent test].

Recently large amounts of Aspergillus restrictus, a species of osmophilic fungi, have been detected in house dust using culture media with low water activity. But little attention has been paid to this fungus as an allergen. In the present study, the authors examined the allergenic activity of A. restrictus by skin prick tests and radioallergosorbent tests (RAST) on 94 asthmatic patients (mean age 12.0, range 3-18). Aspergillus fumigatus, Alternaria alternata and house dust were used for comparison. In the skin prick tests, A. restrictus, A. fumigatus, A. alternata and house dust elicited positive reactions in 8 (8.5%), 8 (8.5%), 15 (16.0%) and 69 (73.4%) patients, respectively. RAST showed positive reactions in 27 (28.7%) subjects for A. restrictus, 22 (23.4%) for A. fumigatus, 35 (37.2%) for A. alternata, and 75 (79.8%) for house dust. These results indicated that some asthmatic individuals showed immediate-type hypersensitivity to A. restrictus, and the prevalence of hypersensitivity of A. restrictus determined by skin prick tests and RAST was comparable with that of A. fumigatus but lower than that of A. alternata or house dust. This indicates that this fungal species may be of importance as a causative agent in atopic diseases.

Adolescent↗
PubMed1990

[Inhalation therapy of antibiotics].

We produced experimental murine Klebsiella pneumoniae pneumonia by air-borne infection using exposure apparatus (LD50: 9.7 X 10 C.F.U./lung). The MIC value of cefazolin was 1.56 micrograms/ml, and that of gentamicin was 0.39 micrograms/ml. We treated this murine pneumonia with aerosolized antibiotics. The infected mice received inhalation of 50 mg (5 mg/ml), 100 mg (10 mg/ml), 200 mg (20 mg/ml) and 400 mg (40 mg/ml) gentamicin were alive. Survival rate of the infected mice treated with inhalation of 1000 mg (100 mg/ml) cefazolin was low, but that of them received inhalation of 500 mg (50 mg/ml) cefazolin was high. On the basis of these experiments it is suggested that aerosol of 50 mg/ml cefazolin gets to alveoli, and inhalation therapy of low level of cephems is proper for bacterial respiratory infections. Inhalation therapy of 50 mg/ml cephem for chronic bronchitis had a marked clinical effect. This proves that aerosol of cephem gets to infected bronchi.

Administration, Inhalation↗
PubMed1990

[Long-term follow-up of tetralogy of Fallot corrected by Okamura's method under simple deep hypothermia].

Corrective surgeries for TOF (Tetralogy of Fallot) were performed in 350 patients from 1967 to 1983 by Okamura's method under simple deep hypothermia. Radical operations were done in all patients, including very young children. The operative techniques had several differences from the standard procedure. Patients were operated on without any extracorporeal perfusion, the VSD was closed by a patch which was attached firmly to the margin of VSD using cross mattress sutures and the right ventricular outflow tract was dilated by infundibular myectomy only, with no use of outflow-patch-plasty. One hundred ten out of 350 patients were investigated by questionnaire and their responses showed that they had few long-term problems. ECG, X-ray, echocardiography and stress test by treadmill were performed in 26 cases. They were divided into two groups by the presence or absence of pulmonary regurgitation (PR). The CTR of the PR (+) group was larger than the PR (-) group (p less than 0.05). There was no statistical difference in cardiac function between the two groups. Few arrhythmias were observed during the exercise test. No residual shunts were found in any of the cases. The occurrence of PR was relatively rare in those who were operated on before their second birthdays. These results suggest that our surgical techniques under simple deep hypothermia are adequate to correct TOF.

Adult↗
PubMed1990

[Diagnosis of acute gastrointestinal bleeding using scintigraphy with 99mTc-labeled red blood cells].

To evaluate the usefulness and clinical significance of scintigraphy using 99mTc-RBC in urgent abdominal bleeding, we performed abdominal bleeding scintigraphy in 20 patients with melena. These patients were admitted to the critical care center. Nine of 20 patients showed positive images with bleeding scintigraphy. Five of 20 patients were referred because of small intestinal bleeding. Four of these 5 patients revealed positive images. Seven of 9 patients who had positive image and four of 11 patients who were negative had open-surgery performed. While angiography was done in 8 patients, only 3 of the 8 patients were proven to have bleeding. These 3 patients also revealed positive images by bleeding scintigraphy. This technique facilitates the screening of bleeding in the ileum, where endoscopic techniques may prove difficult to detect the site of bleeding. We emphasize that abdominal scintigraphy should be performed on patients with G.I. bleeding since this is a more accurate examination than angiography.

Adolescent↗
PubMed1989

Site-specific postural and locomotor changes evoked in awake, freely moving intact cats by stimulating the brainstem.

Locomotor behaviors evoked by stimulating the hypothalamus and the brainstem were studied in freely moving, awake cats. To do this, stimulating microelectrodes were chronically implanted into the subthalamic locomotor region (SLR) in the lateral hypothalamic area (LHA), the mesencephalic locomotor region (MLR) corresponding to the nucleus cuneiformis, the dorsal tegmental field (DTF) and the ventral tegmental field (VTF) of caudal pons along its midline. After recovery from surgery (2-3 days), open field tests were performed to study stimulus effects upon posture and locomotor movements. The stimuli consisted of pulses of 0.2 ms duration of less than 80 microA delivered at 50 pulses/s for 5-20 s. DTF stimulation resulted in suppression of postural support by the hindlimbs. When the cat was in a standing posture, DTF stimulation simply resulted in a sequential alteration of posture to a squatting and then to a final lying posture. In contrast, VTF stimulation evoked an almost opposite series of postural changes to those induced by DTF stimulation. With VTF stimulation, the cat changed from a lying or a squatting position, and then started to walk during continuation of the stimulation. With MLR stimulation, the cat invariably exhibited fast walking and then running movements. It ran straight forward, avoiding collision with walls or other obstacles, and even tried to jump over a fence placed in front of it. With LHA stimulation, the cat started to walk slowly extending its head forward and looking around repeatedly. It tended to walk with a stoop and stealthy steps along the corners of the room. Induced postural and locomotor changes were always accompanied by behavioral arousal reactions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Functional role of the sensory cortex in learning motor skills in cats.

The functional role of corticocortical input projecting to the motor cortex in learning motor skills was investigated by training 3 cats with and without the projection area. After unilateral removal of areas 1, 2, 2 praeinsularis and a part of 5, the cat was placed in a box and trained to pick up a small piece of food from a beaker in front of the box. Since the beaker and the edge of the box had a space in between, the cat had to develop a new motor skill to being the food back to the box across the space. This skill consisted of combined supination and flexion of the paw to hold the food over the gap. In all 3 cats, the training period necessary for acquisition of the motor skill for the forelimb contralateral to the lesioned brain was significantly longer than the period necessary for the forelimb ipsilateral to the lesioned cortex. Ablation of the remaining projection area after completion of the training did not impair the learned motor skill. The results suggest that the input from the lesioned area to the motor cortex participates in learning motor skills.

Animals↗
PubMed1989

[Cellular immune dysfunction in the NOD mouse: suppression of concanavalin A-induced responses in spleen cells by activated macrophages].

It is generally accepted that T lymphocyte-mediated autoimmunity contributes to the pathogenesis of Type 1 diabetes in humans and animals. Using spleen cells from nonobese diabetic (NOD) mice, a model of human Type 1 diabetes, we have analyzed the subset of T lymphocytes by flow cytometry and investigated concanavalin A (Con A)-induced interleukin 2 (IL-2) production and cell proliferation. NOD mice showed a higher percentage of Thy1.2+, L3T4+, and Lyt2+ T lymphocytes than did control ICR mice through the whole age examined. Spleen cells from a large majority of NOD mice were found to generate very low IL-2 production and cell proliferation in response to Con A. However, a few mice preserved their responsiveness to Con A. The following reasons may indicate that macrophage-mediated suppression participates in the deficient function of NOD spleen cells. (a) Macrophage depletion from NOD spleen cells retrieved Con A-induced IL-2 production. (b) Thioglycollate-induced peritoneal exudate cells containing many activated macrophages could completely suppress cell proliferation. (c) Prostaglandin synthetase inhibitor indomethacin reversed the suppression of IL-2 production by macrophages. (d) Conversely, exogenous prostaglandins could show the partial suppression of IL-2 production. These results suggest that activated macrophages suppress the response of NOD spleen cells to Con A mostly through prostaglandins. This impairment may contribute to the pathogenesis of Type 1 diabetes in NOD mice.

Animals↗
PubMed1989

Suppressor T-cell abnormality in NOD mice before onset of diabetes.

To investigate the pathological role of suppressor T-cells in non-obese diabetic (NOD) mice, we stimulated splenic T-lymphocytes from diabetes-prone NOD mice with concanavalin A (ConA) and then evaluated their ability to suppress the lymphocyte-proliferative responses to mitogen and allogenic cells. Lymphocytes from NOD mice showed significantly less suppressor ability than did those from BALB/c mice and non-obese non-diabetic (NON) mice, the corresponding non-diabetic sister strain of the NOD mouse, both in the mitogen response and in the mixed lymphocyte reaction (MLR). We used monoclonal antibodies and flow cytometry to analyze the lymphocytic surface phenotypes, and found markedly fewer Lyt2+ T-lymphocytes (suppressor/cytotoxic T-lymphocyte) in the NOD mice than in both controls after exposure to ConA. These results suggest that suppressor T-cell activity is already depressed in NOD mice before diabetes begins and that a substantial decrease in the number of suppressor T-cells induced by ConA may explain this depressed suppressor activity. This impairment may contribute to the pathogenesis of type 1 diabetes in NOD mice.

Animals↗
PubMed1989

[Changes in muscarinic cholinergic receptors and cholinergic neurons in experimental hydrocephalic rat brain].

Recently, the relationship between neurological disorders and neurotransmitters has received much attention. Many studies have been reported about the changes of neurotransmitters and their metabolites in cerebrospinal fluid (CSF) in hydrocephalus, and it is presumed that neurotransmitters may play a role in the regulation of CSF dynamics. We injected kaolinum suspension into the cisterna magna of rats and created experimental hydrocephalus. Here we define the acute hydrocephalic stage to be the seventh day after injection and the chronic to be the twenty-first day after injection. We made studies about the changes of muscarinic cholinergic receptors in experimental hydrocephalic rat brains using binding assay, macroautoradiography, and microautoradiography with 3H-quinuclidinyl benzilate (QNB), which has a high and specific affinity for muscarinic receptors. We also studied the changes of cholinergic neurons in experimental hydrocephalic rat brains by immunohistochemical methods with anti-choline acetyltransferase (CAT), the antibody for the synthetic enzyme of acetylcholine which is thought to exist only in cholinergic neurons. Muscarinic cholinergic receptors were increased in acute hydrocephalus, and tended to normalize in chronic hydrocephalus but no change was observed in its distribution. There seemed to be no difference in the number of CAT positive cells between normal and hydrocephalic rat brains, but in hydrocephalic rat brain, CAT positive cells were compressed by the dilated ventricles, and they might have fallen into hypofunction. It is thought that muscarinic receptors were increased by some mechanism like denervation hypersensitivity because of the reduction of ACh production or release. Recent advancement of PET or SPECT has made it possible to investigate the changes of neurotransmitter receptors in human brain. Such biochemical examination may offer some information to assess the functional state of hydrocephalus and to find a new approach to its treatment.

Animals↗
PubMed1989

Demonstration of neutrophil chemotactic anaphylatoxins in human dandruff.

In contrast to scales collected from the scalps of nine healthy individuals where a few parakeratotic cells are observable, a large number of parakeratotic cells associated with some infiltrated polymorphonuclear leukocytes (PMNLs) were found in the scales obtained from 11 individuals complaining of dandruff. Therefore, we determined the neutrophil chemotactic properties of the water-soluble extracts of dandruff scales and normal control scalp scales. Aqeous extracts fractionated by Sephadex G-75 showed a potent chemotactic activity only in the fractions of the dandruff patients that eluted with cytochrome C marker (cyt C; molecular weight, 12 kDa). It was comparatively stable to heat but was greatly inhibited by the addition of anti-C5 antiserum. Radioimmunoassay demonstrated that, although small amounts of C5a and C4a anaphylatoxins were demonstratable even in the extracts of normal scalp, they were found in significantly increased amounts in the extracts of dandruff. Moreover, there was a significantly positive correlation between C5a and C4a concentrations in these extracts. These results suggest that classical complement pathway activation with resultant production of C5a anaphylatoxin is involved in the migration of PMNLs into the lesional skin of dandruff.

Adult↗
PubMed1989

Intracranial invasion of scalp carcinoma. Report of five cases.

Among 10 patients with squamous cell carcinoma admitted to our hospital, 5 showed intracranial invasion and 4 died with regrowth of intracranial tumour 9 to 24 months after incomplete extirpation of tumour. We reviewed our experience in the management of advanced scalp carcinoma, from neurosurgical and neuroradiological points of view. Dural invasion failed to be removed completely because of involvement of the middle part of the superior sagittal sinus. Therefore, total resection, facilitated by early detection prior to intracranial invasion, is mandatory for successful treatment of these scalp carcinomas.

Aged↗
PubMed1989

Release of neurotensin by selective perfusion of the jejunum with oleic acid in dogs.

Plasma neurotensin concentrations are rapidly elevated after oral ingestion or intraduodenal infusion of fat, apparently before fat reaches the ileum where neurotensin is highly concentrated. The purpose of this study was to investigate the site of neurotensin release and to determine whether neurotensin is released by direct luminal stimulation by fat in conscious dogs. Dogs were prepared with isolated jejunal or ileal segments and portal vein catheters. Release of neurotensin into the portal venous blood was examined by selective perfusion of each intestinal segment with sodium oleáte. The results of this study show that selective perfusion of the jejunum, but not the ileum, with sodium oleate, caused a significant release of neurotensin. We speculate that release of ileal neurotensin is not due to direct luminal stimulation, but is mediated by local neural or humoral intermediates.

Animals↗
PubMed1989

Effects of exercise on hypocholesterolemia of stroke-prone spontaneously hypertensive rats.

The effects of exercise on hypocholesterolemia, one of the risk factors of cerebrovascular disorders, were examined. 47-51-day-old stroke-prone spontaneously hypertensive rats (stroke-prone SHRs) were assigned to 2 groups, sedentary or exercise, and raised for 8 weeks. The total serum cholesterol level of the exercised group was 17-18% higher (P less than 0.01) than the control group, and the level of cholesterol synthesis in the liver of the former group significantly higher than in the latter. On the other hand, the level of intestinal cholesterol synthesis in the exercised group was significantly lower. The activity of HMG-CoA reductase in the liver microsomes was significantly increased by exercise, but the activity of this enzyme in the small intestine was not affected. A significant correlation was observed between the rate of cholesterol synthesis in the liver and the amount of radiolabeled cholesterol released into the serum. From these results, we conclude that the enhancement of the synthesis and the release of cholesterol in the liver by exercise is a major cause of the exercise-induced increase in serum cholesterol of stroke-prone SHRs.

Animals↗