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Biomedical subjects

M Okada

Publications and source records attributed to M Okada.

At least 1,567 records · Page 87Linked to original sources
PubMed1984

Early ultrastructural changes in choroidal arterioles of spontaneously hypertensive rats.

Ultrastructural changes in the vascular smooth muscle cells of spontaneously hypertensive rats (SHR) aged 7-9 months were studied in the long posterior ciliary artery (LPCA) and they were compared with the findings in the same aged control Wistar Kyoto rats (WKY). The systolic blood pressure was higher than 200 mmHg in the SHR at the postnatal fourth month. The muscle cells in the media of the LPCA in the SHR could be divided into three types according to the electron density of their sarcoplasm, i.e., dark, intermediate or light cells. The electron density depended on the content of actin filaments; the number of the filaments per one micron 2 was determined in the specimens where cross sections of the filaments prevailed, and it averaged 48.7 in the dark cells, 34.1 in the light cells. In WKY, all the muscle cells showed the intermediate density and the number of actin filaments averaged 37.9 per micron 2. It was also observed that the muscle cells migrated into the intima and they were called the intimal cells. These cells in SHR appeared as an aggregated mass underneath the endothelium, but in WKY the individual intimal cells were scattered. These findings were thought to be early ultrastructural changes in response to a rapid elevation of the arterial pressure.

Animals↗
PubMed1984

[Quantitation of left-sided valvular regurgitation by gated cardiac blood pool scan: evaluation of a new approach using the Fourier amplitude ratio].

Utilizing the Fourier amplitude ratio (FA ratio), we evaluated a new approach for quantitating valvular regurgitation by the gated cardiac blood pool scan. The subjects consisted of 36 patients with documented left ventricular regurgitation of grade I-IV (group 1), 24 patients with myocardial infarction including severe cardiac dysfunction (group 2), and 15 normal persons (group 3). From each pixel of the gated cardiac blood pool scan, a time-activity curve was obtained and the first-harmonic Fourier analysis was performed. Two functional images; namely, the phase and amplitude images, were generated. To generate the FA ratio, the region of interest was drawn around each ventricle in the amplitude image. The FA ratio was calculated using the following formula; FA ratio = left ventricular amplitude value/right ventricular amplitude value. The FA ratio was 2.66 +/- 1.75 (mean +/- S.D.) in group 1; 1.29 +/- 0.27 in group 2; and 1.11 +/- 0.19 in group 3. The FA ratio for group 1 was significantly higher than those of groups 2 and 3 (p less than 0.001). There was no significant difference between the FA ratios of groups 2 and 3. In patients with regurgitation, the FA ratio was 1.50 +/- 0.37 in patients with grade I, 1.97 +/- 0.34 in grade II, 2.73 +/- 0.95 in grade III; and 6.65 +/- 2.14 in grade IV. There was a good agreement between the FA ratios and quantitative angiographic estimates of regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Purification and characterization of an antibacterial protein from haemolymph of Sarcophaga peregrina (flesh-fly) larvae.

Three antibacterial proteins were induced when the body wall of Sarcophaga peregrina (flesh-fly) larvae was injured with a hypodermic needle. These proteins were separated and one was purified to homogeneity. The molecular weight of the purified protein was 5000 and its amino acid composition was similar to that of cecropins, which are antibacterial proteins in Hyalophora cecropia (cecropia moth) pupae. This protein was found to have bactericidal activity and to be effective at a concentration of 0.1 micrograms/ml against certain Gram-negative and Gram-positive bacteria.

Amino Acids↗
PubMed1983

Calcium and fibrin gel structure.

Calcium ions (Ca), when present in the gel forming system, were shown to influence liquid permeation of the gels formed, as judged from the Ks-values (permeability coefficients) of the final gels. On increasing Ca concentration, the Ks-values for Fibrin I and Fibrin II gels increase and a maximum is reached at about 10-20 mM for gels formed at ionic strengths between 0.18 and 0.24. For both gels, clotting times (Ct) were shortened on increasing Ca concentration and the shortening was accompanied by increase in Ks. Magnesium also shortened Ct but had no appreciable effect on Ks. The rate of activation of fibrinogen (release of FPA and FPB) was not much affected by Ca, but the activation required for gelation at Ct, decreased with increasing Ca concentration. After the gels were formed, the removal of Ca by EDTA did not change the flow properties. Our results showed that Ca is of importance for formation of the fibrin gel structure, but it may be of minor importance for preservation of the gel structure after its formation. There is a difference between Fibrin I and Fibrin II gels with regard to Ca dependence. The role of calcium in gelation as well as its physiological implications is discussed.

Batroxobin↗
PubMed1983

B cell growth factors and B cell differentiation factor from human T hybridomas. Two distinct kinds of B cell growth factor and their synergism in B cell proliferation.

Human T hybridomas secreting B cell growth factors (BCGF) and B cell differentiation factor (BCDF) have been established. Hybrid clones 77-A, 94-C, and 98-F secreted BCGF that induced proliferation of anti-IgM-stimulated normal B cells. The culture supernatant from 77-A cells could also maintain continuous proliferation of colony-forming B cells, but the factor from 94-C could not. The addition of the supernatant from 94-C cells to that from 77-A cells, however, synergistically augmented the proliferation of colony-forming B cells, demonstrating the existence of two distinct kinds of BCGF and the synergism between them. These supernatants, however, showed no interleukin 2 (IL-2) or BCDF activity. A hybrid clone, 90-E, secreted BCDF. The culture supernatant induced Ig production in Cowan I-stimulated normal B cells or in a transformed B cell line, CESS. However, the supernatant had no BCGF or IL-2 activity. Anti-Ig-stimulated B cells, but not IL-2-dependent T cells, absorbed BCGF activity and CESS cells absorbed BCDF activity but not BCGF activity in the culture supernatants from T hybridomas. Taken collectively, the results demonstrated that IL-2, BCGF, and BCDF were different molecules and acceptors specific for the each molecule are present on the each target cell.

Absorption↗
PubMed1983

Hypophosphatemia induced by intravenous administration of Saccharated iron oxide.

Forty milligrams saccharated iron oxide was given intravenously, daily, to nine iron-deficient patients with moderate to severe anemia. During the 14-42 days of treatment, levels of serum inorganic phosphorus (Pi) decreased significantly and in a stepwise manner (before vs 1 week, P less than 0.005; 1 week vs 2 weeks, P less than 0.01). Seven of the nine patients became hypophosphatemic within 2 weeks and the other two within 4 weeks. In parallel with the decline in serum Pi, the phosphate clearance increased and tubular reabsorption of phosphate decreased. Reversion to normal levels was delayed in patients treated for the longer period.

Anemia, Hypochromic↗
PubMed1983

Paroxysmal nocturnal hemoglobinuria terminating in TdT-positive acute leukemia.

A case of paroxysmal nocturnal hemoglobinuria (PNH) which developed terminal transferase (TdT)-positive leukemia 5 years after the diagnosis of PNH was studied. Most of the leukemic cells were suggestively lymphoid by cytochemistry and electron microscopy, and TdT-positive by immunofluorescence studies. The development of acute lymphoblastic leukemia during the course of PNH suggests that in PNH the clonal abnormality may involve lymphoid cells as well as myeloid cells, thus raising the possibility of the disease being a disorder of the pluripotential stem cell.

Aged↗
PubMed1983

A method for quantification of alternate pronation and supination of forearms.

A method for quantitative evaluation of diadochokinesia test (alternate pronation and supination of forearms) has been developed. Ten parameters that quantify features of movements were established. The method was applied to a group of healthy people and a group of patients with methylmercury poisoning. Significant differences between the two groups were noted in many parameters. To interpret the parameters synthetically, principal component analysis was applied and a scatter diagram on the first two principal components indicated the difference in distribution between the two groups. Among the established parameters, there were six related to regularity. They were combined in a linear form to define a summarized measure for regularity. The measure agreed very well with visual judgment. The obtained results demonstrated the usefulness of the method in daily clinical practices.

Forearm↗