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Biomedical subjects

T Wada

Publications and source records attributed to T Wada.

At least 811 records · Page 45Linked to original sources

Entrainment of human circadian rhythms by artificial bright light cycles.

Artificial bright light cycles (LD 8:16) of about 5000 lux during the light period were applied to two subjects in a temporal isolation unit, who had shown free-running circadian rhythms in sleep-wakefulness and rectal temperature. The circadian rhythms were successfully entrained by the artificial light cycle, but the phase relation of the rhythms to the light cycle was substantially different between the two subjects. The result indicated that the artificial bright lights are able to reset human circadian rhythms.

Adult↗

Measurement of blood pressure and heart-rate variation while resting supine and standing for the evaluation of autonomic dysfunction.

Blood pressure and R-R interval variation were studied during postural changes using a tilting table. The subjects were 64 normal controls and 52 patients with various disorders. None of the normal controls showed postural falls of more than 15 mm Hg in mean blood pressure. The mean loge coefficient of variation of 100 R-R intervals was significantly reduced in groups with Parkinson's disease, spinocerebellar degeneration, Shy-Drager syndrome and diabetes mellitus, compared with a normal control group. Reduced heart-rate variation was frequently associated with sphincter disturbance and orthostatic hypotension.

Adolescent↗

Cell-mediated cytotoxic activity of regional lymph node cells from patients with gastric carcinoma.

The cell-mediated cytotoxic activities of cells from the perigastric lymph nodes (LNC) were assayed in patients with gastric carcinoma. These activities were compared with those of the peripheral blood mononuclear cells (PBM), and also with the LNC of patients with benign lesions. The capacity of LNC to be converted to cytotoxic cells in mixed cell culture was significantly impaired in the cancer patients as compared to that of either the PBM from the same patient, or the LNC from patients with benign lesions. The natural killer cell (NK) activity of LNC was significantly lower than that of the PBM in both groups of patients. The cytotoxic activity induced by phytohemagglutinin activation (PAK) in the LNC from patients with carcinoma, as well as from those with benign lesions was also significantly decreased, when compared to that of the PBM, although the ability of LNC to produce interleukin 2 (IL 2) was significantly increased. The ability of these cells to generate cytotoxicity after activation with IL 2 (LAK) was therefore examined, and a decreased capacity in LNC was observed. These results indicated that the ability of T cells in LNC to develop into cytotoxic cells in patients with gastric carcinoma was impaired, and that the nonspecific cytotoxicity, including NK or PAK, as well as LAK activity, was essentially low in the perigastric lymph nodes.

Carcinoma↗

Natural killer activity in patients with chronic hepatitis treated with OK432, interferon, adenine arabinoside and glycyrrhizin.

Natural killer (NK) activity in the peripheral blood of patients with chronic liver disease was measured using 51Cr labeled K562 cells as target cells. NK activity was elevated but not significantly in patients with chronic hepatitis compared with healthy controls and significantly lower in the patients with hepatocellular carcinoma. The activity decreased in the order of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Although the level of NK activity in patients with chronic hepatitis did not correlate with the level of alanine aminotransferase (ALT), it tended to be elevated in association with elevation of ALT in patients treated with OK432, interferon-beta, glycyrrhizin or adenine arabinoside. In chronic liver disease, phytohemagglutinin (PHA) skin test showed a positive correlation with NK activity. In all patients who were treated with the immunopotentiator, OK432, and whose HBeAg became negative, NK activity was elevated during the treatment. These results suggest that the NK activity in peripheral blood may be related to hepatocytic injury even if this is not the effector mechanism of the injury.

Adult↗

Digital image processing of dentomaxillofacial radiographs.

The improvement in the image quality of dentomaxillofacial radiographs (panoramic radiographs) with the use of a digital image-processing system was examined. Linear and nonlinear unsharp masking techniques were employed for image processing. The quality of the processed images was found to be markedly improved over that in original radiographs. The detail visibility of linearly enhanced images, especially in low-density areas, was superior to that of nonlinearly enhanced images, although the presence of more artifacts and more noise was noted in linearly enhanced images. Radiographic diagnosis in the dentomaxillofacial region can be improved with this system.

Humans↗

Expression of the human adenovirus E1a product in yeast.

We synthesized the 13S mRNA-encoded protein of the early region 1a (E1a) of human adenovirus in Saccharomyces cerevisiae under the control of the yeast GAL7 gene promoter. Similar to the case in HeLa cells, the E1a protein in yeast was phosphorylated and formed multiple bands on sodium dodecylsulfate-polyacrylamide gel electrophoresis. These bands migrated more slowly than expected from the Mr calculated on the basis of the nucleotide sequence of the gene. Synthesis of the E1a protein caused induction of a specific family of heat-shock proteins (Hsp70), which, however, did not confer heat resistance to the yeast. In addition, the E1a production resulted in an elongation of the generation time of yeast from 2.4 h to 3.9 h, which was attributed specifically to elongation of the G1 interval in the cell cycle. In the light of these findings, we suggest that the E1a protein synthesized in yeast exerts a specific function.

Adenovirus Early Proteins↗

Relative deficiency of serine proteinase activities in spleens of aged mice.

We examined the relation of hydrolytic enzymes in spleen to the aging process in mice over a period of 30 months. When the enzymatic activities were expressed as activities per milligrams protein, those of serine proteinases and dipeptidyl peptidase IV (Gly-Pro-AP) significantly decreased with age, whereas that of L-leucine aminopeptidase (Leu-AP) increased significantly. However, when expressed as total activities, the enzymatic activities in spleen generally tended to increase with age, except in the case of serine proteinases, because of the age-related increase in spleen weight. The results were taken to indicate that the activities of serine proteinases become relatively more deficient in the spleen as age increases. The results of a multivariate study maintained this peculiarity of serine proteinases in comparison with other enzymes. The relative deficiency of serine proteinases in spleen may be somehow related to immunodeficiency in aged animals, as judged from similar findings in animal models of systemic erythematodes.

Aging↗

Characterization of rat T cell subset antigen by monoclonal antibody.

6B2-B8 T cell hybridoma cells were used to immunize mice, and immune spleen cells were fused with NS/1 myeloma cells. One clone, designated RTH-7, reacted with 89.5% of rat thymocytes, 30.2% of rat spleen cells, and 42.3% of rat lymph node cells. The RTH-7 reacted with a subset of rat T cells but not with B cells. Double staining analysis demonstrated that RTH-7 stained a rat T cell subset distinct from R1-10B5-positive cells that were known to be equivalent to mouse Lyt-2. It was revealed that RTH-7 and W3/25 recognize different antigenic epitopes on the same molecule. The RTH-7 as well as W3/25 substantially inhibited the production of interleukin 2 by cells in mixed lymphocyte reaction and the lymphocyte proliferation induced by mixed lymphocyte reaction. The RTH-7 inhibited the lymphocyte proliferation induced by Con A whereas W3/25 failed to do so. The RTH-7 defined antigen has a molecular weight of 53,000 under reducing condition and 47,000 under nonreducing condition. The RTH-7 defined antigen showed a wide range of heterogeneity in pI (6.2-8.8). The associated molecule of approximate molecular weight of 27,000 was occasionally detected with the RTH-7 defined antigen in 6B2-B8 T cell hybridoma cells as well as peripheral T cells but not in thymocytes. Thus, RTH-7 detects a cell surface antigen of a functional T cell subset of rat origin.

Animals↗

A survey of 37 cases with basal ganglia calcification (BGC): CT-scan findings of BGC and its relationship to underlying diseases and epilepsy.

Thirty-seven cases that showed bilateral basal ganglia calcification (BGC) were found in 5987 patients. These cases (0.6%) were studied in relation to their CT findings, underlying diseases and epilepsy. CT findings of BGC were divided into "localized" type (33 cases) and "diffuse" type (4 cases). The number of patients with the "localized" type clearly seemed to increase with age. The M:F ratio of the "localized" type was 1:2. The "localized" type was seen in both idiopathic BGC and familial BGC. The "diffuse" type was seen in hypoparathyroidism only. The specific relationship of these two types of BGC to underlying diseases, however, does not fully agree with results so far reported. We experienced a case with familial BGC during this study that appears to be only the 15th so far reported. Partial epilepsy occurred in 75% of epilepsy with BGC, but there seemed to be no direct relationship between BGC and epileptogenicity.

Basal Ganglia Diseases↗