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Biomedical subjects

I Nishimura

Publications and source records attributed to I Nishimura.

88 records · Page 5Linked to original sources
PubMed1982

T cell-mediated cytotoxicity against HBsAg-coated Chang cells in patients with chronic hepatitis: evidence for cytotoxicity mediated by delayed hypersensitivity T cell reaction.

T lymphocytes from 7 (21%) of 34 patients with chronic hepatitis showed positive cytotoxicity against HBsAg-coated Chang cells. This positivity was observed in HBsAg-negative patients having positive blast transformation responses to HBsAg, as well as in patients convalescing and recovered from acute B hepatitis. Levels of S-GPT in these patients were not different from those showing no cytotoxicity. T cell-mediated cytotoxicity against HBsAg-coated hepatocytes in HBsAg-negative patients thus may have no significant pathogenetic role in destruction of hepatocytes and may represent anamnestic response of sensitized T lymphocytes to HBsAg. Positive cytotoxicity against HBsAg-coated Chang cells was also found in 3 of 17 patients with HBsAg-positive chronic hepatitis. All positive cases exhibited blast transformation responses to HBsAg and low HBsAg titers in their sera. Levels of S-GPT in these patients were significantly higher than in those showing no cytotoxicity, suggesting possible presence of T cell-mediated liver cell damage in these patients. T lymphocytes from asymptomatic HBsAg carrier showed no cytotoxicity to HBsAg-coated hepatocytes and no blast transformation responses of lymphocytes to HBsAg. From the results of the parallel occurrence of T cell-mediated cytotoxicity and blast transformation responses to HBsAg, and of presence of lymphotoxin in the supernatant co-cultured HBsAg and cytotoxicity-positive lymphocytes, it seemed likely that T cell-mediated cytotoxicity in our system might be mediated by lymphokine produced by T cells as a result of delayed hypersensitivity reaction in vitro.

Cells, Cultured↗
PubMed1978

Change of glucagon reacting to 30 K antibody in totally depancreatized dogs.

Total pancreatectomy was performed in dogs; and arginine test was conducted at the first, second and third weeks after surgery, and measurement was made of blood glucose, glucagon and insulin on a time-course basis for a comparative study with normal dogs. 1) After total pancreatectomy, glucagon reacting to 30 K antibody decreased once but increased with the lapse of time when no insulin was administered. 2) In the arginine test, glucagon showed a biphasic reaction in normal dogs, but a monophasic reaction in totally depancreatized dogs. This reaction declined three weeks after surgery. 3) When blood samples were taken from the pancreaticoduodenal vein, the left-gastroepiploic and mesenteric veins, during and after arginine was infused for 30 minutes. Glucagon in the pancreaticoduodenal vein increased markedly, but there were no such prominent changes in the left-gastroepiploic or mesenteric veins, Meanwhile, the level of glucagon in the left-gastroepiploic vein increased remarkably in dogs one week after total pancreatectomy.

Animals↗
PubMed1978

Effect of exogenously administered glucagon on plasma glucose levels in totally depancreatized dogs.

Glucagon was administered exogenously via a subcutaneous route to totally depancreatized adult mongrel dogs and studies were made with major emphasis on glucagon effect on the plasma glucose levels. 1. In the totally depancreatized dogs, the plasma glucose levels determined 90 minutes after glucagon injection (40 micrograms/kg s.c.). were compared with the pretreatment fasting plasma glucose levels. The rate of increase in the plasma glucose levels was 5.13 +/- 0.48 times (M +/- SEM) in dogs with low pretreatment level (lower than 100 mg/dl). In dogs with higher pretreatment levels (100-400 mg/dl), the increase was 1.62 +/- 0.40 times. And in dogs with the pretreatment levels higher than 400 mg/dl, the value was 0.90 +/- .07 times. 2. Ninety minutes after regular insulin injection (0.25 U/kg i.v.), glucagon was administered (40 micrograms/kg s.c.), and the changes in the plasma glucose levels were determined. 3. In totally depancreatized dogs, a transient increase in the plasma insulin level was noted when glucagon was administered (40 micrograms/kg s.c.) under infusion of a mixture of glucose and insulin. 4. There was no significant difference in the rate of disappearance of glucagon from the blood between normal and totally depancreatized dogs. 5. It is considered that glucagon would be useful for the treatment of hypoglycemia encountered after total pancreatectomy.

Animals↗
PubMed1977

Changes in polymorphic gene frequencies in strains of chickens selected for resistance to Marek's disease.

Resistance to Marek's disease (MD) was selected over five generations in three strains and their four substrains. 2. MD mortality decreased consistently on natural exposure, but in birds artificially inoculated the mortality increased again in later generations. 3. Changes of gene frequencies at five polymorphic loci--blood group A, B and D, plasma esterase and alkaline phosphatase loci--were examined. 4. The frequencies of blood group A6 and B8 alleles showed a consistent trend of increase and the B11 allele gradually decreased in most strains. The Akp allele of alkaline phosphatase increased significantly in two of seven strains. 5. Comparisons of homozygotes and heterozygotes revealed a significant difference only at the A locus.

ABO Blood-Group System↗
PubMed1976

Leucocyte migration inhibition with inner and outer membranes of mitochondria and insoluble hepatocyte surface membranes prepared from rat liver in patients with chronic hepatitis and cirrhosis.

Patients with chronic liver disease were tested for delayed hypersensitivity to the outer and the inner membranes of mitochondria (OMM and IMM) and the insoluble hepatocyte-surface membranes (IHSM), prepared from rat livers, by means of leucocyte migration inhibition technique. Positive reaction to OMM was found in 37% of patients with chronic persistent hepatitis and 35% of those with chronic active hepatitis and 43% of those with liver cirrhosis (P less than 0-05). That to IMM was 55%, 43% and 36% (P less than 0-05) and to IHSM was 37%, 47% and 45% respectively (P less than 0-05). IHSM was found to contain liver-specific components and patients with positive response to IHSM did not reveal at all a positive reaction to rat renal cell-surface membranes. The incidence of positive response to IHSM was significantly higher (54-2%) in patients with the present or previous infection with HBAg than in HBAg-non-infected patients (21-4%) (P less than 0-05). And there seemed to be a good correlation between a degree of cellular response to purified HBsAg and that to IHSM in these HBAg-infected patients. No correlation, however, was found between that to purified HBsAg and that to OMM or IMM in the same patients. This suggested that the cellular response to either HBsAg or IHSM, both related closely, may play a role in the perpetuation of chronic liver disease.

Cell Membrane↗
PubMedDate not supplied

Evaluation of floating impeller phenomena in a gyro centrifugal pump.

The Gyro centrifugal pump, developed as a totally implantable artificial heart, was designed with a free impeller in which the rotational shaft (male bearing) of the impeller was completely separated from the female bearing. For this type of pump, it is very important to keep the proper magnet balance (impeller-magnet and actuator-magnet balance) to prevent thrombus formation or bearing wear. When the magnet balance is not proper, the impeller is jerked down into the bottom bearing. On the other hand, if magnet balance is proper, the impeller is lifted off the bottom of the pump housing within a certain range of pumping conditions. In this study, this floating phenomenon was investigated in detail. The floating phenomenon was proven by observation of the impeller behavior by means of a transparent acrylic pump. The impeller floating phenomenon was mapped on a pump performance curve. The impeller floating phenomenon is affected by the magnet-magnet coupling distance and the rotational speed of the impeller. To keep the proper magnet balance and to maintain the impeller floating phenomenon at the driving conditions of right and left pumps, the magnet-magnet coupling distance was altered by a spacer that was installed between the pump and actuator. It became clear that the same pump could handle different conditions (right and left ventricular assist) by changing the thickness of the spacer. When magnet balance is proper, the floating impeller phenomenon occurs automatically in response to the impeller revolution. This is called "the dynamic revolutions per minute suspension."

Centrifugation↗
PubMedDate not supplied

Modification of the frictional surfaces of artificial joints.

To overcome the wear problems associated with artificial joint materials, new surface structures with regular patterning were designed and fabricated. The lubrication properties were studied to evaluate the wear of the frictional surfaces. The surface structure was a pattern of "dents" with a diameter of 0.2-1.0 mm and a pitch of 0.6-2.0 mm. The pattern was fabricated on the stainless steel (SUS) surface by a photochemical etching technique with 3 microns depth, and on an ultrahigh molecular weight polyethylene (UHMWPE) surface by mechanical processes. The time dependent changes of frictional force between SUS and UHMWPE were measured, and the surface morphologic changes were observed. The patterned surface showed lower frictional force than the smooth non-patterned surface, and less wear occurred on the patterned sample than on the sample without a pattern. There were optimum sizes for the diameter and the pitch of the pattern. These results demonstrated that lubrication properties could be improved by patterning of the frictional surfaces. The surface patterning was effective in preventing wear of the frictional surface, and the life of an artificial joint could be extended by such patterning.

Biomechanical Phenomena↗