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Biomedical subjects

M Okazaki

Publications and source records attributed to M Okazaki.

At least 487 records · Page 27Linked to original sources
PubMed1985

Cell age-dependent changes in deformability and calcium accumulation of human erythrocytes.

The deformability of human erythrocytes was measured in a rheoscope, as a function of intracellular calcium content (varied with ionophore (A23187) and CaCl2) without complete ATP depletion and echinocytic transformation. Loading calcium into intact erythrocytes (calcium content: 16.8 mumol/1 packed cells = 1.48 amol per cell), the cell volume and energy charge gradually decreased. Further, the membrane fluidity of the lipid portion decreased without crosslinking of membrane proteins. A distinct transition from deformable to undeformable cells was observed by the rheoscope technique: i.e., 50% transition occurred at 40-50 mumol calcium/1 packed cells (= 3.5-4.0 amol per cell) and more than 90% above 100 mumol/1 packed cells (= 6.5 amol per cell) at a shear stress of 140 dyn/cm2. The deformable cells maintained their deformability to ellipsoidal disks independent of the average calcium content. The underformable cells, separated as high-density cells by density gradient centrifugation after calcium-loading, showed lower glucose-6-phosphate dehydrogenase activity than low-density-deformable cells; thus, the calcium-loaded, undeformable cells were presumably in vivo aged cells. The younger cells, fractionated as low-density cells from intact erythrocytes, were more deformable than aged cells. Upon calcium-loading, the younger cells restored their cell volume and deformability, while the aged cells, containing originally more calcium and less ATP, decreased their volume and became undeformable. Therefore, calcium accumulation by ionophore-CaCl2 takes place in preference to aged cells of lower energy metabolism, and leads to cellular dehydration and loss of deformability, due to condensed hemoglobin and altered membrane organization.

Adenosine Triphosphate↗
PubMed1985

Electron spin relaxation of synthetic melanin and melanin-containing human tissues as studied by electron spin echo and electron spin resonance.

Electron spin lattice relaxation times (T1) and the phase memory times (Tm) were obtained for the synthetic melanin system from 3-hydroxytyrosine (dopa) by means of electron spin echo spectroscopy at 77 degrees K. Saturation behavior of the ESR spectra of melanins in melanin-containing tissue and of the synthetic melanin was also determined at the same temperature. The spin lattice relaxation time and the spectral diffusion time of the synthetic melanin are very long (4.3 ms and 101 microseconds, respectively, in the solid state), and the ESR signal saturates readily at low microwave powers. On the other hand, ESR spectra of natural melanins from the tissues chosen for this study, as well as those of synthetic melanins which contain Fe3+ of g = 4.3 and Mn2+ of g = 2, are relatively difficult to saturate compared with samples without such metal ions. These results show clearly that a large part of those two metal ions in sites responsible for the ESR spectral components with these particular g values are coordinated to melanin in melanin-containing tissue, and modify the magnetic relaxation behavior of the melanin. Accumulations of these metal ions in melanins are different from system to system, and they increase in the order: hair (black), retina and choroid (brown), malignant melanoma of eye and skin, and lentigo and nevus of skin.

Copper↗
PubMed1985

Promotion of bone dissolution by excessive fluoride in acidic buffer solution.

In order to quantitatively examine fluoride uptake by bone and the effect on its chemical and physical properties, rat bone was incubated in acidic buffer solutions (pH 5) with fluoride concentrations of 0-1000 ppm F. After 1 wk incubation, there was a substantial increase in the crystallinity of the bone mineral with increasing fluoride concentration in the solution. The calcium concentration in the solutions used for incubation decreased dramatically, with increased levels of fluoride in the solution, approaching a plateau. The phosphate concentration initially decreased, with increasing levels of fluoride in proportion to the decrease of calcium concentration, and then increased when the fluoride concentration of the solution was above 200-300 ppm. These phenomena, when considered with X-ray diffraction data, reflected the formation of CaF2. The increase of the phosphate concentration in the solution suggests that the presence of excessive fluoride in the acidic buffer solution may promote the dissolution of soluble bone apatites, in spite of the dissolution-preventive activity of fluoride.

Animals↗
PubMed1985

Function of reticuloendothelial system on CCl4 induced liver injury in mice.

Phagocytic activity as a function of the reticuloendothelial system (RES) has been studied in CCl4-induced liver injury by using the carbon clearance test. Liver damage in mice was induced by administration of 20% CCl4 in olive oil (p.o.). After a single administration of CCl4, significant increases in liver/body weight ratio, serum GOT and GPT levels, alpha, beta and gamma-globulins and BSP retention, and decreases in serum albumin, an activity of the hepaplastintest and the correct phagocytic activity, alpha value, were found. After 15 administrations of CCl4 (3 times a week), mild increases in serum GPT level and BSP retention and decreases in the activity of the hepaplastintest and both phagocytic indices, K and alpha values, were observed. However, zymosan treatment 3 days before sacrifice induced an increase in K value depressed by multiple administrations of CCl4. The depression of carbon uptake by Kupffer cells can be seen by light microscopy after multiple administrations of CCl4 compared with that of saline and olive oil. These findings indicate that the RES phagocytosis is suppressed more strongly in chronic liver injury by 15 CCl4 administrations than in acute injury by a single one, although the biochemical parameters indicating liver injury are shown to have an opposite tendency. A clear correlation between the alteration of RES activity and the degree of liver injury was not noted.

Alanine Transaminase↗
PubMed1985

[Intra-arterial infusion chemotherapy with anticancer agents for advanced breast cancer--effect and toxicity of mitomycin C and adriamycin].

In 23 cases of primary advanced breast cancer, intra-arterial infusion chemotherapy of Adriamycin (ADR) and Mitomycin C (MMC), which were injected jointly or individually, was performed and its effects and side effects were studied. As for the clinical effects, the response rate (CR + PR) was 73.9% (17/23 cases) and the histological response rate (greater than grade IIb) was 82.6% (19/23 cases). ADR alone (100-150 mg) and MMC (28 mg) + ADR (42 mg) combined regimens were especially superior in both their clinical and histological effects. In metastatic lymph nodes, the histological response rate was 78.9% (15/19 cases). As for the side effects, in the cases treated with MMC, bone marrow suppression such as leukocytopenia and thrombocytopenia was remarkable and took a long time to recover. The above results suggested that the most effective regimen for primary advanced breast cancer using intra-arterial infusion chemotherapy is ADR alone, in single doses of 50 mg up to a total dose of 150-200 mg. Histological examination of the effective cases revealed that the central region of the tumor was more markedly recrotic than the periphery. It was suggested that the grade of the effects on tumor tissues is related to the mechanism of anticancer agents.

Alopecia↗