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Biomedical subjects

M Okazaki

Publications and source records attributed to M Okazaki.

At least 577 records · Page 32Linked to original sources
PubMed1981

[Effect of soedomycin (M3) on the phagocytosis in the mouse (author's transl)].

Effect of M3, an anticancer agent, on the phagocytic activity of the mouse reticuloendothelial system was studied by the carbon clearance method. Lysosomal enzyme activities of peritoneal exudate cells solution (PECs) and peritoneal macrophage (Mp), and morphological changes of Mp were also examined. The K index (phagocytic index) was significantly increased 24 hr after the administration of M3 (250,300 mg/kg, i.p. X 3) as well as that of zymosan (Z: 50 mg/kg, i.p. X 3). The time course on phagocytic activity of Me (300 mg/kg) was also investigated. The index was increased 2, 4, and 96 hr after i.p. administration, but on i.v. administration the index was decreased at 2 and 4 hr, although increased at 72 hr. Microscopically, carbon particles were internalized by Mp of marginal zones between white and red pulp in the spleen, and in the liver, mainly by Kupffer cells. Lysosomal enzyme activities (acid phosphatase and beta-glucuronidase) and cell numbers of PECs were increased as follows: Z greater than M3 greater than Na2HPO4. These enzyme activities in Mp were also increased significantly 72 and 96 hr after i.p. administration. Observing of morphology by Giemsa staining, saline and Na2HPO4 groups showed round monocytes, but in the M3 and Z groups there were enlarged cells with many projections. These results suggest that M3 promotes the phagocytic activity on the reticuloendothelial system in mice and has a stimulatory effect on Mp because of the increase in the lysosomal enzyme activities and morphological changes in the cells.

Acid Phosphatase↗
PubMed1981

[Cast fractures of dental Ni-Cr alloys (author's transl)].

Cast fractures of Ni-Cr alloys were investigated by means of scanning electron microscopy, energy dispersive X-ray spectrometry, electron-probe microanalysis, density measurements, setting and thermal expansion measurements and compressive tests. Three-Ni-Cr alloys for crowns and bridges were cast in spiral configurations by an argon-arc pressured type or an induction argon-pressured type-casting machine. The amount of cast fracture increase with an increase in cast temperature, but not with an increase of holding time at cast temperature. Ni-Cr alloys have more cast fractures in a phosphate-bonded investment than in a gypsum-bonded cristobalite investment. Fracture surfaces have an exposed dendrite structure, indicating the presence of cast porosity. The trigger of cast crack can be a cast porosity and the propagation of crack to fracture may be mainly due to the strength of investments.

Chromium Alloys↗
PubMed1981

Detoxification of ammonia by immobilized urea cycle enzymes.

Detoxication of ammonia was performed by dialysis of ammonia through a hollow fiber unit and by conversion to urea in a column reactor packed with immobilized urea cycle enzymes. Enzymes in the urea cycle could be immobilized by covalently binding on CNBr-activated Sepharose 4B. Ammonia was sequentially converted to urea by immobilized urea cycle enzymes with an ATP-regenerating system. Optimum conditions for the cyclic reaction were obtained theoretically and experimentally for performing continuous urea synthesis in a packed column reactor. Detoxication of ammonia of similar concentration to that in the blood in hepatic insufficiency was analyzed and performed experimentally in an extracorporeal model.

Adenosine Triphosphate↗
PubMed1980

High-performance aqueous gel permeation chromatography of human serum lipoproteins.

A new application of high-performance aqueous gel permeation chromatography was developed for the analysis of human serum lipoproteins. A good combination of columns (TSK GEL, type PW and type SW) was found for the separation of serum lipoproteins: very low-density lipoprotein, low-density lipoprotein and high-density lipoproteins. Analyses of serum lipoproteins from individual normal subjects and pathological subjects were performed by this combination of columns. The effects of pH and salt concentration fo the eluent on the separation of lipoproteins were also investigated.

Chromatography, High Pressure Liquid↗
PubMed1980

Rapid analysis of cholesterol of high density lipoprotein and low density lipoprotein in human serum by high performance liquid chromatography.

A simple and rapid method for the determination of cholesterol in human serum lipoproteins (VLDL, LDL, HDL2, and HDL3) was described. The contents of cholesterol of lipoprotein fractions from a very small amount of serum (20 microliter) can be determined by the enzymatic assay after separation by high performance liquid chromatography in less than 50 min. The method is very useful for studying lipoprotein metabolism and related diseases.

Cholesterol↗
PubMed1980

Analysis of cholesterol in high density lipoprotein subfractions by high performance liquid chromatography.

We succeeded in the separation of human serum high density lipoprotein into their subfractions (HDL2 and HDL3) by high performance liquid chromatography with gel permeation columns (1, 2). The cholesterol contents in HDL2 and HDL3 for normal men and women (n = 42) and for the patients with atherosclerotic heart disease (n = 20) were measured by this separation method. The results in our experiment agree closely with those reported by other investigators using the ultracentrifugal method.

Adult↗
PubMed1980

Orientations of carbonate ions in human tooth enamel studied with use of the CO3-3 radical ions as probes.

With the use of CO3-3 radical ions as probes, it is concluded that the carbonate ions substitute in the apatite lattice of human tooth enamel in two different ways. Most of the carbonate ions in the apatite lattice are aligned with their symmetry axis parallel to the c axis, whereas the remaining carbonate ions are aligned with their symmetry axis perpendicular to the c axis.

Apatites↗
PubMed1980

[Effect of pyrithiamine on rat sciatic nerve. (I) Morphological changes during the early stage of thiamine deficiency (author's transl)].

We observed under light and electron microscopes morphological changes in the rat sciatic nerve during the early stages of a thiamine deficient state as induced by a pyrithiamine (PT: 50 microgram/100g X 6 days) and thiamine deficient diet (TDD). We simultaneously determined thiamine levels in the whole sciatic nerve of rats. Experiments were undertaken with normal control, TDD (rats fed a TDD), PT (PT treated rats) and PTD (PT treated rats fed a TDD) groups. Microscopically, there were numerous shrunken myelinated axons with myelin ovoids of folds in the PT group and many swollen ones in the PTD group. Electron microscopically, we found more advanced lesions in the PTD group than in the other groups. These ultrastructural changes were swelling of Schwann cells, enlarged rough-surfaced endoplasmic reticulum, axonal degeneration with shrinkage, loss of organelle or abnormal myelin sheath, and proliferation of fibroblasts. The thiamine level in the PTD group decreased to 18 approximately 30% that of control in proportion to the morphological changes. On the other hand, the thiamine level in the PT group (55 approximately 61%) decreased slightly more than that of the TDD group (50 approximately 56%), but changes in morphology were vice versa. These results suggest that the morphological changes in the sciatic nerve caused by PT-induced thiamine deficiency differs from changes seen in cases of dying-back neuropathy caused by TDD-induced deficiency, and that PT itself directly affects the nervous system

Animals↗
PubMed1980

[Effect of pyrithiamine on rat sciatic nerve. (II) Morphological changes during the last stages of thiamine deficiency (author's transl)].

We observed under light and electron microscopes morphological changes in the rat sciatic nerve during the last stages of a thiamine deficient state as induced by pyrithiamine (PT: 50 microgram/100g X 11 days) and thiamine deficient diet (TDD), in which rats experienced severe tetanic convulsions. Experiments were undertaken with normal control, PT (PT treated rats) and PTD (PT treated rats fed a TDD) groups. Grossly, 4 out of 9 rats in the PTD group had severe tetanic convulsions on the 12th day and there were no neurologic signs in the PT group. Microscopically, many of the myelinated axons in the animals in the PT group showed shrinkage with myelin ovoids and folds, but in the PTD group, there was swelling as well as shrinkage. Despite the difference in general-symptoms between the PT and the PTD groups, axonal degeneration in the both groups, as determined electron microscopically was almost to the same degree and the convulsed rats in the PTD group showed the severest changes in the myelin sheath. These ultrastructural changes included swelling or vacuolation of Schwann cells, axonal degeneration with the appearance of a myelin like structure, collection of neuro-tubules or vacuoles, invasion of Schwann cell or/and myelin fragments into the periaxonal space, and active phagocytosis by the macrophages. These results suggest that PT directly affects the nervous system and that the dysfunction of the sciatic nerve following PT-induced thiamine deficiency originates from the central nervous system.

Animals↗