Search PubMed⌕ Search

Biomedical subjects

M Okuno

Publications and source records attributed to M Okuno.

234 records · Page 13Linked to original sources
PubMed1976

Mechanical stimulation of starfish sperm flagella.

1. The responses of starfish sperm flagella to mechanical stimulation with a microneedle were analysed. Flagellar movement was recorded by high-speed microcinematography and by stroboscopic observation. 2. The amplitude of the bending wave of a flagellum was restricted over its entire length when the microneedle was brought near to the flagellum at its proximal region. Beyond the restricted part, the amplitude of the wave, and the bend angle, became smaller than those of a normally beating flagellum, while the curvature was practically unchanged. 3. When the tip of the microneedle was in contact with the flagellum, propagation of the bending wave beyond the microneedle was inhibited. The part of the flagellum between the base and the microneedle continued beating in some cases and stopped beating in other cases. The flagellum beyond the arrested part stopped beating and remained straight. When the microneedle was removed, the bending wave which existed in the part of the flagellum proximal to the microneedle, or the wave which was passively formed de novo at the time of the removal of the microneedle, propagated over the arrested part towards the tip. 4. A flagellum amputated by a microneedle in a medium containing ATP continued beating with a small amplitude, small curvature, small bend angle and low frequency. When the amputated flagellum was passively bent by a microneedle at the region near the point of amputation, this bend propagated towards the tip with a constant bend angle. 5. The beating frequency of the flagellum could be modulated by the application of a rhythmic external force generated by vibrating a microneedle near the flagellum. The beating was completely synchronized with vibration of the microneedle in the frequency range from 23 Hz to 43 Hz.

Adenosine Triphosphate↗
PubMed1975

Amino acid composition of dynein and comparison with myosin.

A comparison is made between dynein [flagellar ATPase; EC 3.6.1.3], purified from sea urchin sperm flagella, and muscle myosin. The amino acid composition of dynein was found to be statistically different from that of myosin. The same was true of their tryptic fragments retaining ATPase activity, i.e., Fragment A of dynein and heavy meromyosin. At low ionic strength, no superprecipitation took place when ATP was added to a mixture of dynein and actin, and stimulation of the Mg2+-ATPase activity of dynein remained below 50% even when a one-hundred-fold excess of actin was present. No viscosity drop was caused by adding ATP to a solution containing dynein and actin. Anti-myosin antiserum did not react with dynein, while anti-Fragment A antiserum formed no precipit-n line against myosin. Furthermore, the amount of dynein that combined with F-actin was less than one-fifth of the amount of dynein that fully combined with microtubules. These results are consistent with the dissimilarity in enzymatic and other physiocochemical properties of these two proteins.

Actins↗
PubMedDate not supplied

Application of stains-all staining to the analysis of axonemal tubulins: identification of beta-tubulin and beta-isotubulins.

The cationic dye, Stains-all, is known to stain brain beta-tubulin blue and alpha-tubulin red (Serrano, L. et al. (1986) J. Biochem. Biophys. Methods 12, 281-287; Serrano, L. et al. (1989) Biochem. Int., 19, 235-246). The present experiments show that this stain can also be applied to detect beta-tubulin in axonemal tubulins from various sources such as cilia of protozoa, sperm flagella of echinoderm, and sperm flagella of mollusc. Furthermore, these experiments showed that it selectively stains isoforms of axonemal beta-tubulin blue following isoelectric focusing, whereas those of alpha-tubulin are stained red. These results indicate that Stains-all staining is a useful tool for electrophoretic analysis of axonemal tubulins.

Animals↗
PubMedDate not supplied

Changes in serum and hepatic levels of immunoreactive prolyl hydroxylase in two models of hepatic fibrosis in rats.

Changes in serum and hepatic levels of immunoreactive prolyl hydroxylase (IRPH) as well as cellular localization of the enzyme were studied in 2 models of hepatic fibrosis, which was induced in male rats either by subcutaneous administration of CCl4 (Group A) or by intraperitoneal injection of porcine serum (Group B). Hepatic fibrosis appeared at the 8th week in Group A and at the 12th week in Group B, and liver cirrhosis developed at the 16th week in both models. Although tissue contents of hydroxyproline (HP) and IRPH increased in both models, only HP levels correlated with the degree of fibrosis. Serum IRPH levels and serum asparate aminotransferase (AST) activities increased, showing a significant positive correlation, in group A, whereas both remained in a control range in Group B. Moreover, in another model which received a single intraperitoneal injection of CCl4, serum IRPH showed a marked increase and then a rapid decrease in parallel with the change in serum AST. Immunohistochemical analysis also showed a difference between the two fibrosis models: in group A, IRPH was positive mainly in parenchymal cells in the peripheral zone of the pseudolobulus, while in group B the staining was diffuse. These results indicate that the elevation of serum IRPH is, at least in part, due to the parenchymal cell damage, and that IRPH levels should be carefully evaluated when being used as a parameter to estimate the activity of fibrogenesis in the liver.

Alanine Transaminase↗
PubMedDate not supplied

Cyclin D1 overexpression and prognosis in colorectal adenocarcinoma.

Recently, it has been reported that cyclin D1 plays a major role in oncogenesis in various cancers; however, there have been few studies on the association of cyclin D1 overexpression and prognosis of patients with malignant tumors. We evaluated the prognostic significance of cyclin D1 overexpression in colorectal adenocarcinoma. One hundred twenty-three specimens resected from patients with colorectal adenocarcinomas were investigated by staining with a monoclonal antibody against cyclin D1. As a result, both overall survival and disease-free survival were significantly poorer in the patients with tumors strongly positive for cyclin D1 than in those with cyclin-D1-negative or weakly positive tumors. The 5-year survival rate of the patients with tumors strongly positive for cyclin D1 was 53.3%, while the 5-year survival rates of patients with cyclin-D1-negative and weakly positive tumors were 96.2 and 78.8%, respectively. Moreover, multivariate analysis indicated that cyclin D1 overexpression is an independent predictor of disease recurrence in our patients. In conclusion, cyclin D1 overexpression may be useful as a predictor of disease recurrence in colorectal adenocarcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Effect of fat emulsion in patients with liver disorders.

The effect of fat emulsion in preoperative patients (n = 17) with liver disorders was studied by liver-function tests, intraoperative liver biopsy specimens, intravenous fat tolerance tests, and serum fatty acid analyses. There was no difference between liver-function tests before and after the administration of fat emulsion. Before the administration of fat emulsion, the levels of serum lipids were relatively low, and serum fatty acid patterns were abnormal. However, after the administration of fat emulsion, serum lipid levels increased, and serum fatty acid patterns became nearly normal. There was a significant correlation between the total fat intake and serum linoleic acid change before and after the administration of fat emulsion. From this equation, the total fat intake required for a normal range of serum linoleic acid was calculated to be 7 g/kg fat. These results suggest that the administration of fat emulsion improves serum fatty acid patterns without a deterioration of liver function in preoperative patients with liver disorders, but total intake of 10% fat emulsion greater than 70 ml/kg might induce higher serum fatty acids than in healthy control subjects and cause overload in these patients.

Adult↗
PubMedDate not supplied

A single-blind comparison of bromperidol and sulpiride in hospitalized schizophrenics.

Fourty-five schizophrenic inpatients were randomly assigned to bromperidol or sulpiride in an 8 week single-blind clinical trial. No statistically significant differences were observed for final global improvement rating. Regarding BPRS items and compared to sulpiride, bromperidol was particularly effective to relieve emotional withdrawal and hallucinatory behavior, although the only significant between group difference was in favour of sulpiride for improvements of somatic concern. No significant differences were observed for all PES items, although sulpiride was found more effective for hypochondriasis and neurotic complaint as was bromperidol for hallucination and disturbance of self-conscious. The rate of side-effects and abnormal laboratory test results were comparable in the two groups. They were not severe enough to require termination of administration. Bromperidol and sulpiride are concluded to have different clinical profile in the treatment of schizophrenic hospitalized patients.

Adult↗