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Biomedical subjects

M Kasai

Publications and source records attributed to M Kasai.

At least 541 records · Page 30Linked to original sources
PubMed1979

Determination of reflection coefficients for various ions and neutral molecules in sarcoplasmic reticulum vesicles through osmotic volume change studied by stopped flow technique.

Osmotic volume change of sarcoplasmic reticulum vesicles was studied by following the change in light-scattering intensity using a stopped flow apparatus. From the analysis of the initial rate of scattering change, reflection coefficients for various ions and neutral molecules were determined. The following are typical results: K+, 0.72; Tris+, 0.98; choline 1; NO3-, 0.32; Cl-, 0.46; methanesulfonate, 0.62; gluconate, 0.96; glycerol, 0.86; and glucose, 1. When the K+ permeability was increased in the presence of 10(-6) g valinomycin/ml, the reflection coefficient for K+ changed from 0.72 to 0.31. It was found that there was a close relationship between the reflection coefficients and the permeabilities of the solutes. Hydraulic conductivity was also determined from the initial rate of light scattering change and was not different for the different solutes. The water permeability was estimated to be 2.1 x 10(-3) cm/sec at 23 degrees C.

Animals↗
PubMed1979

Inhibition of anion permeability of sarcoplasmic reticulum vesicles by 4-acetoamido-4'-isothiocyanostilbene-2,2'-disulfonate.

The permeabilities of sarcoplasmic reticulum vesicle membrane for various ions and neutral molecules were measured by following the change in light scattering intensity due to the osmotic volume change of the vesicles. 4-Acetoamido-4'-isothiocyanostilbene-2,2'-disulfonate (SITS), which is a potent inhibitor for the anion permeability of red blood cells membrane, inhibited the permeability of sarcoplasmic reticulum for anions such as Cl-, Pi and methanesulfonate, while it slightly increased that for cations and neutral molecules such as Na+, K+, choline and glycerol. Binding of 5 mumol SITS/g protein was necessary for the inhibition of anion permeability. These results suggest the existence of a similar anion transport system in sarcoplasmic reticulum membrane as revealed in red blood cell membrane.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1979

Direct evidence that natural killer cells in nonimmune spleen cell populations prevent tumor growth in vivo.

Relatively large numbers of nonimmune spleen cells do not protect against the local growth of two lymphomas. However, this heterogeneous population of splenic lymphocytes contains a subset of cells that efficiently protects against in vivo tumor growth. This cell population (cell-surface phenotype Thyl.2(-)Ig(-)Ly5.1(+)) represents less than 5 percent of the spleen cell population and is responsible for in vitro NK-mediated lysis. Although these studies clearly and directly demonstrate that Ly5(+) NK cells selected from a heterogeneous lymphoid population from nonimmune mice can protect syngeneic mice against local in vivo growth of two different types of tumor cells (in contrast to other lymphocyte sets within the spleen), they do not directly bear upon the role of NK cells in immunosurveillance. They do indicate that highly enriched Ig(-)Thyl(-)Ly5(+) cells, which account for virtually all in vitro NK activity, can retard tumor growth in vivo. It is difficult to ascribe all anti-tumor surveillance activity to NK cells, because they probably do not recirculate freely throughout the various organ systems of the body. Perhaps NK ceils may play a role in prevention of neoplastic growth within discrete anatomic compartments where there is rapid differentiation of stem cells to mature progeny (e.g., bone marrow, spleen, and portions of the gastrointestinal tract)and may normally act to regulate the growth and differentiation of non-neoplastic stem cells. Long-term observation of chimeric mice repopulated with bone marrow from congenic or mutant donors expressing very low or very high NK activity may help to answer these questions.

Animals↗
PubMed1979

Preoperative assessment of resectability for carcinoma of the thoracic esophagus. Part I. Esophagogram and azygogram.

The length and radiologic type of tumor, esophageal axis and azygogram were examined in 208 patients with carcinoma of the thoracic esophagus who underwent esophageal resection from 1965 to 1975. An histologic examination was performed on all resected specimens. These examinations were used as diagnostic aids to determine the resectability of esophageal carcinoma before surgery. Tumor length did not seem an adequate parameter on deciding resectability; nor did the radiologic type of tumor. Examination of the esophageal axis was in determining resectability. The azygogram gave the most accurate information about resectability of these 4 parameters. The probability of a correct diagnosis regarding differentiation of noncurative a3 lesions from other resectable lesions was 85.6%.

Adult↗
PubMed1979

Neuromuscular defect after suppression of ion conductance.

In rat skeletal muscle, trimetazidine (TMZ) caused a transmission defect without directly blocking binding of acetylcholine--ionophore impairment. In vivo, TMZ produced low-amplitude and cumulative depression of successive muscle responses, and immediate posttetanic exhaustion. These features differed from the effects of alpha-bungarotoxin (alpha-BuTx) or immunization with acetylcholine receptor (experimental autoimmune myasthenia gravis [EAMG]). In vitro, TMZ-induced block was similar to both alpha-BuTx-induced block and EAMG in many respects, but there were differences in endplate potentials evoked during and after rapid repetitive activations. These differences suggest that antibodies to the acetylcholine receptor do not affect the ionophore.

Acetylcholine↗
PubMed1979

Experimental autoimmune myasthenia gravis and cholinergic ionophore: an electrophysiologic study.

Rabbits were immunized with purified acetylcholine receptor from Narke electroplax japonica. A defect of neuromuscular transmission, physiologically identical to human myasthenia gravis, developed when antibodies against the receptor were found in serum. To clarify the mode of action of these antibodies, changes in the endplate current of frog muscle fibers were recorded after exposure to immune rabbit sera. The rabbit sera depressed the amplitude of the endplate current, but caused no change in the time course or the dependence of amplitude and half-decay time on membrane potential. Antibodies may affect acetylcholine binding without impairing ionophore function.

Animals↗
PubMed1979

The screening test of various chemotherapeutic drugs in primary malignant melanoma cells and human malignant melanoma cell line (TM-1).

The sensitivities to various chemotherapeutic drugs of the primary malignant melanoma cell of the esophagus and the malignant melanoma cells established from human skin were studied by determining the incoporation of 3H-thymidine into tumor cells using the tissue culture method. The incorporation of 3H-thymidine was depressed by a low concentration of Actinomycin D in malignant melanoma cells of the esophagus and by a low concentration of Adriamycin or Actinomycin D in the established malignant melanoma cells. When Actinomycin D was clinically used according to the experimental results, the subcutaneously metastasized tumor was remarkably reduced.

Aged↗
PubMed1979

On a new continuous cell line (TM-1) derived from malignant melanoma.

A continuous cell line of malignant melanoma has been established. The tumor specimen was obtained from a left axillary lymph node of a malignant melanoma originating in the abdominal skin of a 67-year-old woman. The cell line has been designated TM-1. Explant specimens showed positive dopa staining, but after 2 years and 4 months, or 60 generations of cell passage, the dopa staining is now weakly positive. Treatment with DBcAMP that causes marked morphological changes induces melanin production and lowers the proliferative ability of the cells. These changes were reversible. Transplantation of the cells to nude mice resulted in the formation of large tumors consisting of epithelioid cells and spindle cells. Morphologically, the majority of the cell population in vitro was polygonal epithelioid cells, but the cell passage produced a large number of spindle cells. The shape of the TM-1 cells was examined by scanning electron microscopy. Depending upon the culture conditions, either of these cell types could be predominated, indicating that both cells are of the same origin.

Aged↗
PubMed1979

Prolonged survival time of allogeneic skin grafts in host pretreated with somatic cell hybrids and prednisolone.

By applying somatic cell hybrids to transplantation immunity, the prolongation of survival time of mouse skin allografts was investigated. The hybrid cells (LJ) were made by cell fusion between L cells derived from C3H/He mouse and JLS-V9 cells derived from BALB/c mouse with UV-irradiated Sendai viruses. Skin grafts from female (C3H/He . JmsX BALB/c . Slc) F1 donors were transplanted to male BALB/c . Slc. The survival of the transplant in BALB/c pretreated with the LJ cells and prednisolone showed a significant prolongation, compared with that in animals pretreated with only prednisolone or the LJ cells. The mean survival time and standard deviation of the grafts in mice injected with 1 X 10(5) LJ cells i.v. 4 days before the grafting, and subsequently treated with prednisolone 50 mg/kg i.p. 1 day before and at the time of the grafting were 17.3 +/- 2.2 days. Controls were 9.2 +/- 0.4 days. The mechanisms of prolongation of skin grafts were discussed in terms of cell-mediated immunity and humoral factors. Somatic cell hybrids are useful, not only for inducing immunological enhancement, but also for studying the function of major histocompatibility antigens in cellular immunity and can be applied to clinical organ transplantation.

Animals↗
PubMed1979

Structure of nanaomycin E, a new nanaomycin.

A new component, nanaomycin E, has been isolated from the culture broth of Streptomyces rosa var, notoensis, which had been found to produce nanaomycins A, B, C and D. Nanaomycin E was an epoxy derivative of nanaomycin A and was converted into nanaomycin A and 4a-epi-nanaomycin B by treatment with sodium hydrosulfite in an acidic aqueous solution. 4a-epi-Nanaomycin B was quantiatively converted into nanaomycin A under alkaline conditions.

Anti-Bacterial Agents↗
PubMed1979

Serological characterization of rat leukemia lines, DBLA-1, -6, and -9.

Three lines of rat leukemia, DBLA-1, -6, and -9, were studied serologically by complement-dependent cytotoxicity test. DBLA-1, -6, and -9 were killed by anti-lymphocyte sera, anti-Thy-1.1 sera, and rabbit anti-rat brain sera absorbed with AKR/J brain. However, anti-T and anti-B lymphocyte sera had no cytotoxic effect on DBLA-1, -6, and -9. Furthermore, DBLA-6 and -9 did not absorb the cytotoxic activity of anti-T serum on thymocytes, while DBLA-1 slightly absorbed the cytotoxic activity. These results indicate that DBLA-1, -6, and -9 are of lymphoid origin and possess rat Thy-1 antigens, but lack mature T-lymphocyte antigens. On the other hand, peroxidase-positive myelogenous leukemia L1005 failed to react with any of the antisera used.

Animals↗
PubMed1979

Heterologous antiserum to a subpopulation of thymocytes and lymphomas in rats.

Immunization of rabbits with rat leukemia DBLA-6 resulted in the production of antisera which upon absorption with hepatoma cells were specific for rat immature T lymphocytes. The antisera showed cytotoxicity against thymocytes and killed 75 approximately 90% of them, whereas the antisera had no cytotoxic effect on peripheral lymphocytes from the spleen, lymph node, and bone marrow of rats. The antisera also showed cytotoxicity against rat lymphatic leukemia and lymphoma cells of all lines tested but not against rat myelogenous leukemia and erythroleukemia cells. The cytotoxic activity of anti-DBLA-6 serum was completely absorbed with rat brain or thymocytes.

Animals↗