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Biomedical subjects

R Ohnishi

Publications and source records attributed to R Ohnishi.

At least 37 records · Page 2Linked to original sources
PubMed1983

Effect of polyamines on synthesis and degradation of guanosine 5'-diphosphate 3'-diphosphate.

The effect of polyamines on the in vitro and in vivo synthesis and degradation on guanosine 5'-diphosphate 3'-diphosphate (ppGpp) has been studied in Escherichia coli. The presence of 2 mM spermidine lowered the optimal Mg2+ concentration for ppGpp formation from 17 mM to 11 mM. The formation of ppGpp in the presence of 2 mM spermidine and 11 mM Mg2+ was about 15% greater than that in the presence of 17 mM Mg2+. At a concentration of less than 11 mM Mg2+, spermidine was found to stimulate ppGpp formation greatly. Putrescine did not cause any effect. When a polyamine-requiring mutant of E. coli (EWH319) was starved for an amino acid by the addition of valine, spermidine stimulated ppGpp formation. The degradation of ppGpp was not influenced significantly by polyamines.

Bacterial Proteins↗
PubMed1983

[Effect of ACNU, a water-soluble nitrosourea, on cell cycle of cultured glioma cells--flow cytometric analysis].

Cytotoxic and cytokinetic effects of 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl) 3-nitrosourea hydrochloride (ACNU) on cultured rat and human glioma cells (C-6 and KC) were studied in vitro. Exponentially growing culture cells were exposed to ACNU at the final concentrations of 5 micrograms/ml, 20 micrograms/ml, and 80 micrograms/ml, respectively. The cytotoxic effect was evaluated by inhibition of cell growth and the cytokinetic effect was analyzed by DNA histogram using a flow cytometer. Inhibition of cell growth was dose-dependent in ACNU and C-6 cells were more resistant than KC cells. The growth of C-6 and KC cells were not inhibited at all by low concentrations of ACNU (5 micrograms/ml, 20 micrograms/ml), however, at these concentrations a marked accumulation of treated cells in S and G2+ M phases was evident. The accumulation in S and G2+M phases was dose-dependent and it was more prominent in KC than C-6 cells. ACNU-treated cells accumulated initially in S phase and then in G2+M phase. After maximum accumulation in G2+M phase, the cells seemed to be released into G1 or G0 phase. These results indicate that the cytokinetic effect of ACNU (5 micrograms/ml, 20 micrograms/ml) is more conspicuous than the cytotoxic effect on C-6 and KC cells.

Animals↗
PubMed1982

S-100 protein in human glial tumours. Qualitative and quantitative studies.

The authors studied a total of 48 human glial tumours for S-100 protein, an extremely acidic, protein specific to the nervous system, by immunohistochemistry and by micro-complement fixation assay in order to evaluate S-100 protein as an index for malignancy of glial tumours. All of 48 glial tumours analyzed in the present study demonstrated variable amounts of S-100 protein which might serve as a biochemical cell marker for glial tumours. The mean value of S-100 protein content in 3 ependymomas is higher than those of 19 low-grade (grades I, II) astrocytomas and 26 high-grade (grades III, IV) astrocytomas, being lowest in the latter. A statistically significant (P less than 0.001) difference in S-100 protein levels between low- and high-grade astrocytomas is observed, but not for ependymoma. At present, however, no correlation can be found between S-100 protein content of a tumor and the patient's survival time. Immunoperoxidase staining for S-100 protein in high-grade astrocytomas is generally weak in intensity and heterogeneous throughout the section, whereas that in low-grade astrocytomas and ependymomas is relatively strong and homogeneous, indicating that high-grade astrocytomas consist of a more heterogeneous population of tumour cells in terms of S-100 protein. These results show that the investigation of S-100 protein in a glial tumor is valuable to a certain extent in assessing the degree of differentiation or malignancy of the tumour.

Adolescent↗
PubMed1981

Endoscopic retrograde pancreatic parenchymography.

Endoscopic retrograde pancreatic parenchymography was performed using the technique of endoscopic retrograde cholangiopancreatography. Contrast material was prepared from a nonionic surfactant combined with either sodium iothalamate or sodium and meglumine diatrizoate. With this method, a smooth contour of the pancreas and homogeneous pattern of the parenchyma were shown in the normal pancreas, while an irregular contour of the pancreas, unhomogeneous pattern of the parenchyma, and diminution of the area of the pancreas were found in chronic pancreatitis. In pancreatic carcinoma, a filling defect of the pancreatic field was seen. In the 186 cases studied, the only complication observed was a transient rise in serum amylase level.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1980

Impression method of the colon using sodium alginate--an experimental evaluation in dog.

An experimental study using adult dog was conducted on the impression of the colon whereby a screening test is done by making a mold of the intestine with sodium alginate. The mold of the intestine could be obtained easily and safely in a short time. Protrusions about 2 mm in diameter corresponding to lymphoid tissue of the rectum and sigmoid colon and shallow depressions on the surface of the protrusions were exactly imprinted on the surface of the mild. Compared with the barium study and endoscopy, this method requires neither special equipment nor high-grade technique, can be done easily in a short time and was not inferior in the diagnosis accuracy. Sodium alginate used in this method is a safe substance which is being used clinically as a plasma expander and laxative in addition to being used as an additive to various foods. When injected into the intestine, it exerted no injurious action whatsoever. from these findings, the possibility of this method being used clinically was considered high.

Alginates↗
PubMed1980

Development of impression method of the colon using sodium alginate--experimental evaluation by the use of intestinal phantom.

We devised an impression method of the colon using sodium alginate as a screening method for diseases of the lower part of the colon and evaluated its usefulness by means of an intestinal phantom. Sodium alginate, when mixed with water, kept enough fluidity immediately after mixing and could easily be poured into the phantom. With this paste gelatinized sharply in the phantom about two minutes after, an impression of the intestinal phantom could easily be made. Sodium alginate is a safe substance which is already used clinically. This method is thus expected to become popular as a screening method for diseases of the lower part of the colon.

Alginates↗
PubMed1978

The outer segments of photoreceptive pinealocytes in the pineal organ of the funa, Carassius gibelio langsdorfi. A scanning electron microscopic study.

The form and size of the outer segments of photoreceptive pinealocytes in the pineal organ of the funa, Carassius gibelio langsdorfi, were observed with the scanning electron microscope. The height of the outer segments measures between 1 and 3 micrometer and the diameter varies widely from 1.5 to 8 micrometer. Various forms of outer segments, i.e. a slender type, a dome-like type, a cap-like type and a helical type, were demonstrated. The parallel-oriented filamentous processes of the inner segments have the same length as the outer segments and a diameter of approximately 100 nm; they are projections from the apical border of the inner segment and surround the cone-like outer segments. The processes make a right angle with the lamellar disks. The distance between two processes averages 100 nm. The lamellar disks of the outer segments are oriented at right angles to the modified cilium in the basal part, but the angle often changes in the peripheral part, where the lamellar disks are raised and become parallel to the cilium.

Animals↗