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Biomedical subjects

M Kasai

Publications and source records attributed to M Kasai.

At least 523 records · Page 29Linked to original sources
PubMed1980

Magnesium permeability of sarcoplasmic reticulum vesicles monitored in terms of chlortetracycline fluorescence.

The Ca2+ and Mg2+ permeabilities of sarcoplasmic reticulum vesicles were measured by using a fluorescence chelate probe, chlortetracycline. The Mg2+ permeability was studied extensively. The data were analyzed under the assumption that the increment of fluorescence intensity is proportional to the amount of the divalent cations inside the vesicles. The validity of this assumption was confirmed by the tracer method with Ca2+. The presence of Ca2+ or Mg2+ had little effect on the Mg2+ efflux, but greatly affected the Ca2+ efflux. In the absence of extravesicular divalent cations, the permeabilities for Ca2+ and Mg2+ were almost the same, but the Ca2+ permeability was slightly reduced by the presence of Mg2+ and greatly reduced by Ca2+. In the absence of extravesicular divalent cations, the Ca2+ and Mg2+ permeabilities increased in parallel with increasing pH. For example, the permeation times for Mg2+ and Ca2+ were about 3 min at pH 6.5 and 20 s at pH 8.1 at room temperature. Kinetic analysis of the fluorescence change suggested the existence of two kinds of vesicles with different permeabilities.

Animals↗
PubMed1980

Phosphorylation of gizzard myosin light chain and the ATPase reaction and superprecipitation of skeletal acto-gizzard myosin as functions of ATP concentration.

Three different reactions are known to occur in a combined system of skeletal actin, gizzard myosin, and gizzard native tropomyosin. They were studied as functions of ATP concentration. (a) At around 1 microM ATP in the presence of an ATP-regenerating system, two of the three reactions, superprecipitation and ATPase reaction, occurred independently of calcium and were not accompanied by the third reaction, phosphorylation of myosin light chains. (b) Relatively high concentrations of ATP were required for calcium-dependent phosphorylation and for calcium-activated ATPase reaction. It is suggested that the apparent Km value for myosin light-chain kinase and that for acto-phosphorylated myosin-ATPase are approximately 10(-4.0) M and 10(-5.5) M, respectively. (c) The calcium-dependent phosphorylation and the calcium- activated ATPase reaction were closely coupled, but they were only indirectly coupled with superprecipitation. (d) In some of the responses to change in ATP concentration, (a)-(c), skeletal acto-gizzard myosin was similar to skeletal acto-skeletal myosin. It was also similar in that sulfhydryl groups of myosin are involved in the calcium regulation of actomyosin-ATPase and its superprecipitation in both cases.

Adenosine Triphosphatases↗
PubMed1980

Inulin exclusion volume of sarcoplasmic reticulum vesicles under various solvent conditions.

The inulin exclusion volume of sarcoplasmic reticulum vesicles was studied using the ultracentrifugation method, after equilibrium penetration of solutes had been established under various solvent conditions. The intravesicular volume in equilibrium decreases with increasing salt concentration, while it does not change with neutral molecules. The concentrations of salt ions which caused the intravesicular volume to decrease to a half of the maximal volume were as follows; about 200 mM for KCl and NaCl, about 30 mM for CaCl2 and MgCl2. The mechanism of the volume change can be explained in terms of the Donnan pressure model on the basis of the existence of fixed charges inside the vesicles.

Animals↗
PubMed1980

Donnan potential in sarcoplasmic reticulum vesicles measured by using a fluorescent cyanine dye.

The Donnan potential in sarcoplasmic reticulum vesicles prepared from rabbit skeletal muscle was measured by using a fluorescent cyanine dye, diS-C3-(5) (3,3'-dipropylthiadicarbocyanine iodide). The Donnan potential is caused by the existence of negative fixed charges inside the vesicles. On average, sarcoplasmic reticulum vesicles have internal negative fixed charges of 420 nmol/mg protein at pH 6.8. The fixed charges are mainly due to low affinity Ca2+ binding proteins. The Donnan potential in sarcoplasmic reticulum vesicles was about -72 mV in 5 mM K-MES buffer (pH 6.8). When Ca2+ was accumulated into sarcoplasmic reticulum vesicles with ATP, the concentration of negative fixed charges decreased from 140 mM to 95 mM due to Ca2+ binding to the negative fixed charges, and sarcoplasmic reticulum vesicles were depolarized by about 10 mV. It was found that there are two types of sarcoplasmic reticulum vesicles, one type (60%) having many negative fixed charges inside the vesicles and the other (40%) having few fixed charges.

Animals↗
PubMed1980

Antiglycolipid autoantibody detected in the sera from systemic lupus erythematosus patients.

A high incidence of autoantibody against the neutral glycolipid "asialo GM1" was observed in sera from patients with systemic lupus erythematosus (SLE) with neurological disorders, using an immunoflocculation test. The sera from 14 out of 17 cases of SLE with neurological disorders showed antibody activity against asialo GM1 but not against the following glycolipids: asialo GM2 GM1, and galactocerebroside. In another 87 cases of SLE without any history of seizures, as well as 61 cases of other autoimmune diseases (rheumatoid arthritis, progressive systemic sclerosis, mixed connective tissue disease, etc.) and 20 cases of various neurological diseases (epilepsy, multiple sclerosis, etc.), no antibody could be detected. In general, the antibody titer was high several months, even years, before and/or after the seizure, though the titer was low at the time that patients showed definite neurological symptoms. Immunochemical characterization with Sephadex G-200 chromatogrphy and protein A-Sepharose CL-4B affinity column indicated that the antiasialo GM1 was probably an autoantibody belonging to the immunoglobulin G class. The above results suggest that this newly found autoantibody plays a role in the pathogenesis of neurological disorders accompanying SLE.

Autoantibodies↗
PubMed1980

Effects of epinephrine, ouabain, and insulin in experimental autoimmune myasthenia gravis.

To gain a clue to the target of anti-AChR antibody, rats with acute and chronic experimental autoimmune myasthenia gravis (EAMG) that was induced by immunization with Narke anti-acetylcholine receptor (AChR) were studied using agents acting on active Na-k transport. Postsynaptic response to epinephrine was defective in chronic EAMG with high titers of antibody, suggesting that active Na-K transport system modulated by cyclic adenosine monophosphate (AMP) may be affected primarily by antibody. Sensitivity to ouabain was less than normal in acute EAMG and became close to normal when treated with anticomplementary factor. Findings suggest that acute EAMG is a case of functional denervation. Normal response to insulin occurred in all phases of EAMG.

Animals↗
PubMed1980

Survival of mouse embryos frozen and thawed rapidly.

Mouse morulae were frozen rapidly to -196 degrees C in the presence of 1.0-2.5 M-DMSO by a 3-step procedure; the samples were seeded at -4 to -8 degrees C, held at -20 degrees C in an ethanol bath for 10 min, suspended over liquid nitrogen at approximately -100 degrees C for 10 min and then plunged directly into liquid nitrogen at -196 degrees C. The cooling rate between -20 and -75 degrees C was approximately 17 degrees C/min. In all concentrations of DMSO significantly higher proportions of embryos developed to fully expanded blastocysts after 48 h in culture after rapid thawing (360 degrees C/min) than after slow thawing (25 degrees C/min). The highest survival rates were obtained for the embryos frozen rapidly in the presence of 1.5 and 2.0 M-DMSO (36 and 53% respectively). Various methods for removal of DMSO (2.0 M) were tested with the 3-step freezing and rapid thawing procedures. The best results for development to fully expanded blastocysts were obtained with PBS + 2.0 M DMSO + 0.5 M-sucrose (2 min) followed by PBS + 0.5 M-sucrose (2 min) at room temperature (82%) and with stepwise dilution in PBS at 30 degrees C (70%). When 26 embryos developed to blastocysts in culture after rapid freezing and thawing were transferred into 2 recipients, 11 newborn young (42%) were obtained.

Animals↗
PubMed1980

Differentiative and proliferative effects of (But)2cAMP, n-butyric acid and prednisolone on the malignant melanoma cell line (TM-1) in vitro and in vivo.

Both (But)2cAMP and n-butyric acid suppressed the proliferation of TM-1 cells and induced the formation and elongation of the cellular processes in vitro. Prednisolone stimulated the proliferation of TM-1 cells and increased the number of polygonal cells in vitro. These results indicated that (But)2cAMP and n-butyric acid induce the differentiation of TM 1 cells, whereas prednisolone brings the cells in an undifferentiated state. The growth of TM-1 cell tumor transplanted into nude mice was suppressed by 5 mg of (But)2cAMP and 1 mg of theophylline. Remarkable histological changes were seen in the tumors treated with these agents as compared with untreated tumors. This suggests that (But)2cAMP suppresses the proliferation of TM-1 cells in vivo.

Animals↗
PubMed1980

Correlation between the mixed lymphocyte tumor cell culture reaction (MLTR) and some histological characteristics in esophageal cancer.

The mixed lymphocyte tumor cell culture reaction (MLTR) using autochthonous peripheral and lymph node lymphocytes was performed on 21 patients with esophageal cancer. Ten of 16 cases (62%) in peripheral lymphocytes and 9 of 16 cases (56%) in the lymph node lymphocytes showed positive reaction. There was no correlation between stimulation index (SI) and the degree of lymph node metastasis which is one of the determinants of clinical stage (Guide Lines for the Clinical and Pathologic Studies on Carcinoma of the Esophagus, 1976). Many cases showed positive reaction in MLTR even if their tumors were at advanced stage. SI of MLTR on the patients who died of a relapse in a short time within one year after operation was found to be low levels. There was no remarkable correlation between MLTR and PPD skin reaction. The results of MLTR were compared with histologic differentiation grades of tumor tissues; intraepithelial spread, vascular invasion, sinus histiocytosis of the regional lymph nodes, and follicular hyperplasia of the regional lymph nodes. There was a minor correlation between the results of MLTR and sinus histiocytosis of the regional lymph nodes, and follicular hyperplasia of the regional lymph nodes. There was a minor correlation between the results of MLTR and sinus histioction. The results of MLTR were compared with histologic differentiation grades of tumor tissues; intraepithelial spread, vascular invasion, sinus histiocytosis of the regional lymph nodes, and follicular hyperplasia of the regional lymph nodes. There was a minor correlation between the results of MLTR and sinus histiocytosis of the regional lymph nodes.

Carcinoma, Squamous Cell↗
PubMed1980

Tetrocarcins, novel antitumor antibiotics. II. Isolation, characterization and antitumor activity.

Novel antitumor antibiotics, tetrocarcin complex composed of three components (A, B and C) were isolated from the culture broth of Micromonospora chalcea KY11091 through various procedures. Tetrocarcins showed marked activity against experimental tumors such as mouse sarcoma 180 and mouse leukemia P388. Multiple injections showed better therapeutic effect against tumors. Mode of action of tetrocarcin A against Bacillus subtilis was found to be through the inhibition of RNA synthesis.

Aminoglycosides↗
PubMed1980

Burkitt's lymphoma cell line bearing surface IgA and negative for nuclear antigen of Epstein-Barr virus (EBNA).

A new continuous cell line, TL-1, was established in tissue culture from Burkitt's lymphoma arising at the ileocecal region. It has been maintained for the past two years. The cells were small and round, and grew in a suspension culture. Population doubling time was approximately 36 hours, The cells revealed the chromosomal abnormality i.e. translocation between 8 and 14 chromosomes, which was reported on some Burkitt's lymphomas. This line was negative for nuclear antigen of EB virus (EBNA) and bore surface IgA and not any receptors. Inoculums of 10(7) cells produced tumors in the athymic nude mice. The histological appearance of the tumor was consistent with the Burkitt's lymphoma. Ultrastructural findings showed nuclear blebs and clefts. As far as we know, this was the first cell line of Burkitt's lymphoma with t(8q-; 14q+) in Japan and perhaps the first lymphoma cell line with surface IgA.

Animals↗
PubMed1980

Characterization of immunosuppressor cells in rats immunized with solubilized tumor-associated antigens prepared from a methylcholanthrene-induced fibrosarcoma.

Antiimmune responses in rats previously immunized with soluble tumor antigens prepared by sodium deoxycholate (DOC-STA) from chemically induced fibrosarcoma KMT-17 were measured by the Winn assay. Enhancement of tumor growth was demonstrated at a tumor:effector ratio of 1:500 with DOC-STA-immune spleen cells, although inhibition of tumor growth was demonstrated at a tumor:effector ratio of 1:100. The tumor-neutralizing ability of KMT-17-immune spleen cells was abrogated when DOC-STA-immune spleen cells were added to a mixture of KMT-17 cells and KMT-17-immune spleen cells. This suppressor activity of the spleen cells was diminished by the treatment with rabbit anti-rat T-cell serum and immune complement. The suppressor activity of DOC-STA-immune spleen cells was also shown in 51Cr release assay and was specific for the tumor line used. After fractionation of spleen cells from DOC-STA-immune rats by the Ficoll density gradient, the cells in the light layer showed an enhancing effect on tumor growth detected by the Winn assay, whereas the cells in the heavier region of the gradient had an inhibiting effect.

Animals↗
PubMed1980

The glycolipid asialo GM1 as a new differentiation antigen of fetal thymocytes.

Antibody directed to the neutral glycolipid "asialo GM1" was found to react with the majority of thymus lymphoid cells lacking characteristic T cell markers in mice at an early embryonic stage (13 days of gestation). The proportion of these asialo GM1-positive cells (asialo GM1+ cells) decreased strikingly thereafter, contrasting with an increased fraction of lymphocytes possessing T cell surface markers such as Thy-1, Lyt-1, and Lyt-2. After about 18 gestational days, only a few asialo GM1+ cells were detected in the thymus as well as in other lymphoid organs. Double-staining analysis of the embryonic thymocytes (13 days of gestation) with anti-asialo GM1 and anti-Thy-1 demonstrated that thymocytes stained with anti-asialo GM1 did not react with anti-Thy-1, and vice versa. Morphologic examination by immunoelectronmicroscopy demonstrated that these asialo GM1+ cells were mainly composed of immature, large lymphoid cells having large nucleoli and relatively abundant cytoplasm with many polysomes. These results suggest that asialo GM1 is present on very early thymocytes and is lost as the mature murine T cell protein antigens Thy-1, Lyt-1, and Lyt-2 develop on these cells. The antibody to this glycolipid is a useful tool for studying embryonic thymic differentiation.

Animals↗
PubMed1980

Retroperitioneal lymphangiomyomatosis with lymphedema of the legs.

Retropertioneal tumor is demonstrated by lymphangiography in a 28 year old woman with lymphedema of both legs. Retroperitioneal tumor was subtotally extirpated, with subsequent subsidence of the swelling of both legs. According to the pathologic examination of the extirpated specimens, lymphangiomyomatosis was confirmed. This is the fisrt case reported in the literature of lymphangiomatosis presenting with lymphedema of the leg in the absence of pulmonary involvement, pleural or abdominal effusion.

Adult↗