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Biomedical subjects

S Takeyama

Publications and source records attributed to S Takeyama.

At least 91 records · Page 5Linked to original sources
PubMed1984

Perfusion preservation of cadaver rat pancreas: II. Culture after perfusion and successful transplantation.

We designed a new process for culturing pancreatic islets and applied this method to cultures of rat pancreatic islets which had degenerated during preservation by the perfusion-method for 6 hours under the condition of hypothermia and oxygenation. The objective was to determine the extent of the original function. Transplantation of these so-treated islets was also attempted. When pancreatic islets isolated from the pancreas after 6-hour-perfusion were cultured, morphological restoration was apparent within the first 3-4 days. Insulin contents of the culture media renewed every 3 days, ranged from 851 to 1,134 microU/ml/two islets during culture period of 21 days. In the glucose-loading test, insulin secretion of the islets was the same as that of islets in the control experiments. Transplantation of these islets into the portal vein of streptozotocin-induced diabetic rats resulted in a good recovery from the diabetic state.

Animals↗
PubMed1984

Effects of diltiazem on the physicochemical properties of rat erythrocyte and liposome membrane: comparison with pentoxifylline and propranolol.

In vitro effects of the coronary vasodilator diltiazem on rat erythrocytes and liposomes were studied in comparison with propranolol and pentoxifylline. Diltiazem improved the deformability of rat erythrocytes, reduced the viscosity of rat erythrocyte suspensions, and protected the erythrocyte against hypotonic hemolysis at concentrations above 10(-4) M, 10(-5) M and 5 X 10(-7) M, respectively. Diltiazem at 5 X 10(-4) M also improved the impaired deformability of ATP-depleted erythrocytes, whereas it affected neither the adenine nucleotide level nor the phosphorylation of spectrin in the erythrocytes. Diltiazem enhanced the interaction of 1-anilino-naphthalene-8-sulfonate, a fluorescent probe, with erythrocyte ghosts at concentrations above 5 X 10(-6) M and, above 5 X 10(-5) M, inhibited the (Na+ + K+)-ATPase activity of the erythrocyte ghosts. Diltiazem reduced the microviscosity of both erythrocyte ghosts and liposomes prepared from rat erythrocyte lipids. Diltiazem induced aggregation of the liposomes prepared from rat erythrocyte lipids, phosphatidylserine or phosphatidylinositol, but it did not affect the liposomes prepared from a mixture of phosphatidylethanolamine and phosphatidylcholine (1:1). I-Diltiazem, a stereo-isomer of diltiazem, exhibited equipotent effects, compared with diltiazem, on these parameters. Propranolol showed similar properties, but pentoxifylline shared none of the above properties, except that it improved the deformability of erythrocytes. From these results, it is suggested that diltiazem may affect the erythrocyte membrane by interacting with acidic phospholipids and thus reduce the microviscosity of the membrane, improve erythrocyte deformability and protects the erythrocyte against hypotonic hemolysis.

Animals↗
PubMed1983

Hypoglycemic activity of 1-alpha-(3,4-dimethoxyphenethylaminomethyl) -2-hydroxybenzylalcohol 1/2 fumarate (TA-078) in the mouse, rat and dog.

1-alpha-(3,4-Dimethoxyphenethylaminomethyl)-2-hydroxybenzylalcohol 1/2 fumarate (TA-078) is a new hypoglycemic agent structurally different from any existing hypoglycemic drug. It depresses the rise of blood glucose when it is orally administered to glucose-loaded mice, rats and beagle dogs at minimal doses of 1, 10 and 2.5 mg/kg, respectively. In contrast with tolbutamide, TA-078 hardly affected fasting blood glucose levels in rats and dogs and only weakly reduced fasting blood glucose levels in mice. Oral administration of TA-078 to KK mice also improved glucose tolerance, while no improvement was observed in streptozotocin-diabetic rats. TA-078 elevated plasma immunoreactive insulin (IRI) levels in mice and rats soon after its oral administration. In fasted rats, TA-078 caused only a transient increase in plasma IRI but did not affect plasma immunoreactive glucagon (IRG) levels in the early phase after its administration. On the other hand, tolbutamide induced a sustained increase in plasma IRI and a transient but marked decrease in plasma IRG. In perfused rat pancreas, TA-078 stimulated insulin secretion. The stimulation by 10 micrograms/ml TA-078 in the perfusion liquid required the presence of a normal concn (5.6 mM) of glucose, whereas the same concn of tolbutamide stimulated insulin release even at a low glucose concn (2.8 mM).

Animals↗
PubMed1983

[Determination of malignancy of cartilaginous tumors (2). Determination of malignancy by nuclear DNA contents and their distribution patterns in cartilaginous tumors].

In 40 different types of cartilaginous tumors, the number of binuclear cells was calculated and DNA content was examined using fluorescent Feulgen cytophotometric technique. In 7 enchondromas and 1 synovial chondromatosis, the DNA content was diploid in 7 and hypotetraploid in 1, and showed a unimodal normal distribution. The number of binuclear cells was 0.1-0.45%, and the mean DNA content was below 4. These cases showed no evidence of disease after curettage and bone graft. The follow-up period was from 4 years 6 months to 7 years 1 month, averaging 6 years 2 months. In 2 enchondromatoses and 2 benign chondroblastomas, the DNA content was diploid and showed a unimodal normal distribution. One chondromyxoid fibroma showed a broad-unimodal tetraploid distribution, and one benign chondroblastoma showed a broad-aneuploid distribution. The nuclear DNA content was sometimes histologically similar to that of chondrosarcoma in some benign cartilaginous tumors. In 5 secondary chondrosarcomas, the DNA content was hypo- or hypertetraploid, hexaploid, and showed broad-unimodal or broad-bimodal distribution. The number of binuclear cells was from 13% to 23%. Although the size of the nucleus was small, the number of binuclear cells was evidently numerous. The preferred treatment for secondary chondrosarcoma is principally wide resection, but amputation is sometimes indicated in cases of recurrence and large tumor size. The follow-up period was from 2 years 2 months to 18 years 11 months, averaging 9 years 11 months. All 5 patients were surviving at the time of follow-up. The DNA content in chondrosarcoma was mostly hypo- or hypertetraploid, hexaploid, or octaploid and showed broad-unimodal, broad-bimodal or broad-aneuploid distribution. The number of binuclear cells was 0.55-3.5%. The mean DNA content was proportional to the number of binuclear cells, the positive correlation between the mean DNA content and the number of binuclear cells was found (p less than 1%).

Adolescent↗
PubMed1982

Quantitative determination of trimetoquinol in plasma as its mixed pentafluoropropionyl-trimethylsilyl derivative by gas chromatography mass spectrometry.

A method is described for the determination of the bronchodilator trimetoquinol in plasma, based on selected ion monitoring gas chromatography mass spectrometry employing a deuterated trimetoquinol as internal standard. N-methyl-(trimethylsilyl)pentafluoropropionamide and N-methyl-bis-pentafluoropropionamide were prepared for derivatization of trimetoquinol into a mixed O-TMS-N-PFP derivative, which was found to be the most suitable form in terms of sensitivity, specificity and efficiency. The calibration curve was linear in the range of 2-50 ng ml-1, and the lower limit of detection was 0.1 ng ml-1 of rat plasma.

Animals↗
PubMed1982

Experimental studies on cryopreservation combined with the cultural process of isolated rat pancreatic islets.

Recently many investigators have attempted transplantation of isolated islets of Langerhans in an expectation of therapeutic effects in patients with diabetes. In the course of time, preservation of the islets was found to be a prerequisite for successful transplantation. In the present studies, we used our newly designed method of preserving islets, i.e., cryopreservation combined with the cultural process before and after freezing, and we examined the insulin-releasing activity of the islets and attempted transplantation of the islets so-obtained. As to the insulin-releasing activity, the islets cryopreserved after short-term culture increased insulin output as compared with those cryopreserved without culture. Damage to Langerhans' islets resulting from isolation and cryopreservation was overcome during the culture. Transplantation of Langerhans' islets cultured for 3-4 days before and after the cryopreserving process produced favorable results.

Animals↗
PubMed1981

[Clinicopathological study of twenty-two cases of benign chondroblastoma (author's transl)].

Benign chondroblastoma, a rare bone tumor clinically and histologically resembles giant cell tumor. We have experienced twenty-two cases of histologically confirmed benign chondroblastoma over the 25 year period from 1952 to 1978. The age of the patients ranged from 10 to 46 years, with an average of 20 years. Fifteen cases were in the second decade. Males were predominant to females with a ratio of 2.7:1. Location of the tumor varied widely. The tumor was located in the long bones in 18 out of 22 and limited to the epiphysis in 15. Detailed histological examination in twelve cases with hematoxylin-eosin, alucian blue, toluidine blue, silver impregnation and safranin-O staining, revealed positive staining with alucian blue and PAS. PAS positive granules wee found within cytoplasm and identified as glycogen granules by electron microscopy. However, metachromasia was not always positive and none of these cases stained positive with safranin-O. Rich reticulin fibers encircled each tumor cell and each group of cells. Electronmicroscopic study of 4 cases revealed two types of giant cells. The cell membrane had many microvilli-like protrusions, and the nuclei of the tumor cells were irregular in appearance and had large indentations. Sometimes many fine filaments and electron dense fine granules were observed in intercellular chondroid space. Morphological study of cultured cells was done in two cases. Morphology of these tumor cells proved to be different from fibroblasts, cultured chondrocytes and macrophages. Tumor cells moved rapidly and had undulating membranes at the pseudopodia. From these findings, we speculated that the origin of the benign chondroblastoma cell may be histiocytic cells. Surgical treatment of this tumor was carried out as follows. Curettage was performed in 16 cases, with bone graft in 15, resection 4 and amputation in two. Recurrence was noted on two cases, although no further recurrence occurred after reoperations for nine and twelve years respectively.

Adolescent↗
PubMed1980

Analysis of gas chromatography/electron capture detector sensitive substances in human serum in relation to the determination of iodochlorhydroxyquin concentration.

We found that human sera can be divided into five types depending on the gas chromatography/electron capture detector (GC/ECD) chromatogram pattern. A preliminary GC/MS study on one of the GC/ECD peaks has suggested the presence of a hitherto unknown iodine-containing substance of probably endogenous origin.

Chromatography, Gas↗
PubMed1980

Studies of hypolipidemic agents. 1. Synthesis and hypolipidemic activities of alkoxycinnamic acid derivatives.

More than 110 derivatives of alkoxycinnamic acids were synthesized and their hypolipidemic activities were evaluated in a screening system with rats. Cinnamic acids, alpha-methylcinnamic acids, and their various esters with a higher p-alkoxy substituent were found to possess hypolipidemic activities higher than or comparable to that of clofibrate. The proper length (C12--C16) and the para position of the alkoxy substituent seem to be essential for activity. Chloroethyl and methacryloxyethyl esters and monoglycerides of some of the active p-alkoxycinnamic acids were more active than the corresponding free acids.

Animals↗
PubMed1979

Typical and atypical osteosarcomas: a clinicopathologic study of sixty-two cases.

Of 62 cases of histologically confirmed osteosarcomas, 50 long bone cases aged under 30 years were grouped as "typical" osteosarcoma, and the other 4 long bone cases and 8 short and flat bone cases were grouped as "atypical" osteosarcoma. Gross and microscopic findings of the lesions, postmortem findings, and survival of the patients were compared between the two groups. Small round cell-type tumor cells and relatively well-differentiated foci resembling osteoblastoma were more often found in the atypical than in the typical osteosarcomas. Although patterns of metastasis were not very different between the two groups, 2 of 6 autopsied short and flat bone cases showed no metastasis. Five-year survival rates of both groups were similar, each about 25%. Six patients of the typical and only one of the atypical osteosarcomas are alive without recurrence more than 6 years after amputation.

Adolescent↗