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Biomedical subjects

F Watanabe

Publications and source records attributed to F Watanabe.

337 records · Page 19Linked to original sources
PubMedDate not supplied

Blood level of mitochondrial aspartate aminotransferase as an indicator of the extent of ischemic necrosis of the rat liver.

To assess the severity of ischemic liver injury, we examined release of mitochondrial aspartate aminotransferase (EC 2.6.1.1) and its cytoplasmic isozyme from the ischemic rat liver into the circulation. Their patterns of leakage were quite different: the level of cytoplasmic aspartate aminotransferase reached a peak soon after the circulation to the ischemic liver was restored, while that of mitochondrial aspartate aminotransferase increased slowly, reaching a maximum after more than 10 hr. On anoxic incubation of mitochondria isolated from the normal liver, oxidative phosphorylation capacity was lost within 2 hr, at which time no leakage of matrix enzymes was observed: more than 10 hr after-loss-of-oxidative phosphorylation were needed for the matrix enzymes to leak out of the mitochondrial membrane. Since the viability of cells is considered to depend on the capacity of oxidative phosphorylation, it is highly likely that the delayed appearance of mitochondrial aspartate aminotransferase in blood indicates the postmortem changes of injured cells. In fact, the cumulative activity of mitochondrial aspartate aminotransferase but not cytoplasmic aspartate aminotransferase in circulation after ischemic liver injury correlated fairly well with the decrease of total adenine nucleotides which were monitored to measure viable cells. The difference between mitochondrial aspartate aminotransferase and cytoplasmic aspartate aminotransferase as quantitative indices of hepatic necrosis may be due to the relative stability of the former and significant inactivation of the latter during hepatic ischemia. Therefore, the determination of mitochondrial aspartate aminotransferase in blood may be useful in the assessment of liver necrosis after ischemic injury.

Adenine Nucleotides↗
PubMedDate not supplied

Enzyme immunoassay for cortisol in serum using cortisol 21-amine.

Cortisol 21-amine (21-amino-11beta,17-dihydroxy-4-pregnene-3,20-dione) was prepared and an enzyme immunoassay for cortisol in serum was established using cortisol 21-amine conjugated with alkaline phosphatase. The minimal amount of cortisol detected was 1ng/tube and the measurable range was from 1 to 80 microgram/d1, using 10 mu 1 of serum sample. This enzyme immunoassay satisfied the standard criteria of dilution, accuracy and precision. The values correlated well with those obtained by radioimmunoassay. This enzyme immunoassay is applicable to the routine determination of serum cortisol in any clinical laboratory. Cortisol 21-amine was found to be a useful derivative for preparing cortisol-enzyme conjugate in enzyme immunoassay.

Amines↗
PubMedDate not supplied

Accelerated conversion of dehydroepiandrosterone sulfate to estrogen in a patient with Crow-Fukase syndrome and diabetes mellitus.

About 28% of patients with the Crow-Fukase syndrome exhibit glucose intolerance which may be induced by low serum levels of dehydroepiandrosterone (DHEA). We report a patient with the Crow-Fukase syndrome who exhibited non-insulin dependent diabetes mellitus (NIDDM) worsened prior to admission. He received the DHEA sulfate (DHEA-S) infusion test to evaluate aromatase activity. This patient exhibited an increase in aromatase activity measured by the conversion of the intravenously loaded DHEA-S to estrogen, and low serum levels of DHEA and DHEA-S. These abnormalities returned to nearly normal during the administration of prednisolone, 60 mg per day. No adverse effect on his diabetes was observed during the corticosteroid treatment. Five control patients with diabetes but without the Crow-Fukase syndrome showed no increase in the conversion of DHEA-S to estrogen, which suggests that aromatase activity is normal in diabetes. The increase in aromatase activity in our patient may have led to a low serum concentration of DHEA that in turn caused glucose intolerance and a deterioration of the diabetes prior to admission. Glucocorticoid therapy may be beneficial in Crow-Fukase syndrome to improve the distorted metabolism of DHEA with no adverse effect on the diabetes.

Aromatase↗
PubMedDate not supplied

The effects of recombinant interleukin 2 on HBe antigen positive chronic hepatitis B.

Recombinant interleukin (IL-2) was administered to 16 patients with HBe antigen-positive chronic active hepatitis in which the diagnosis was ascertained histologically. In 7 of the 16 patients, a decrement of the serum HBe antigen value was observed (Group A). In group A, the findings showed an increment of peripheral Leu 11-positive cells and NK and LAK cell activity, an acute exacerbation during and after IL-2 administration, disappearance of HBc antigen observed in liver biopsy histology, and decrement of serum DNA-p activity. However, seroconversion of HBs antigen was not observed and no case showed the elimination status of continuous HB virus infection. On the other hand, in the other 9 patients (Group B), these changes were not observed and the existence of a HLA type difference between Group A and B was shown by HLA analysis. These results indicated that the immune responses mediated by IL-2 may play an important role in the development of chronic hepatitis B, and these results may be regulated genetically.

Adult↗
PubMedDate not supplied

Analysis of stress distribution in a screw-retained implant prosthesis.

Four types of implant superstructures were screwed onto implant bodies, and the strains created around the implant bodies were compared and analyzed within the IMZ Implant System. Three IMZ implants were embedded in the center of a polyurethane block (30 x 40 x 30 mm), and a total of 16 superstructures was fabricated by 4 methods: 1-piece cast, 1-piece cast/split soldering, soldering, and passive fit. Six strain gauges were placed on the surface of the block 1 mm apart. Three embedded implants were numbered, and a fixed partial denture was placed on these implants and screwed by a torque wrench using 14.5 Ncm torque. This procedure was repeated 7 times for each fixed partial denture, and each created strain was measured when the last screw was tightened. In all fixed partial dentures, strains were produced around the implant bodies when screws retaining the prosthesis were tightened, and the strain was relieved with unscrewing. The magnitude of strain was greater with the 1-piece cast method or the section/solder method than with the soldering and passive-fit methods. Of the 2 soldering methods, when the screw on the middle implant was tightened before those on the terminal 2 implants, the magnitude of strain was lower with the soldering method than with the 1-piece cast/split soldering method. When the order of screw tightening was changed, there were significant differences in the magnitude of strain at each gauge with the soldering method. With the passive-fit method, no differences in the magnitude of strain attributable to the order of screw tightening could be detected. The magnitude of strain produced around a screw-retained implant prosthesis was significantly lower with the passive-fit method when compared to the other 3 fabricating methods. Furthermore, the implants prepared by the passive-fit method were not affected by the order of screw tightening.

Analysis of Variance↗