Biomedical subjects
Publications and source records attributed to K Nose.
Adenine and its related compounds stimulated the incorporation of [3H]-uridine both into acid-soluble and insoluble fractions of cultured rat liver cells. The incorporation of [3H]-thymidine or -leucine was not affected by the addition of adenine. Rate of RNA synthesis as measured by [32P]-incorporation was not increased by adenine.
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Pure clones with high alkaline phosphatase (ALP) activity were isolated from Chinese hamster ovary (CHO-K1) cells which showed no detectable ALP activity. ALP-positive cells appeared at the frequency of 10(-4) in the N-methyl-N'-nitrosoguanidine-treated cell population. With respect for cellular morphology, plating efficiency and several other enzymatic activities, no distinct difference was found between the original CHO-K1 cells and its ALP-positive variants, although some alterations in karyotype were found. Levels of ALP activity in these clones was stably maintained during serial cultivation. Some of the enzymological properties of ALP in the isolated clones were similar to those in bone or kidney.
Several subclones with high alkaline phosphatase (ALP) activity were isolated from ALP-negative Chinese hamster ovary cells (CHO-K1). When inoculated into cheek pouch membranes of Syrian golden hamsters treated with anti-hamster thymocyte serum (ATS), ALP-negative CHO-K1 cells produced progressively growing tumors, whereas the cells of ALP-positive subclones did not, although small nodules were formed temporarily. The animals injected CHO-K1 cells died of tumor by 35 days after grafting, and metastases in liver and lung were revealed on autopsy. The histological features of the resultant neoplasms were consistent with fibrosarcoma. In animals transplanted with the cells of ALP-positive subclones, neither tumor death, nor metastasis formation was observed.
Spermine, spermidine, putrescine and agmatine were examined for their cytotoxicity to mammalian cells in tissue culture. Spermine exhibited the highest cytotoxicity among them. It was followed by spermidine. Putrescine and agmatine showed little toxicity but rather acceleration of cell proliferation in some concentrations. Among 16 kinds of rat cells and strains and a mouse cell strain examined, liver cells, fibroblasts, and cells serially grown in a protein-free synthetic medium were sensitive to spermine in the order described. Normal liver cells were more sensitive than hepatoma cells, and normal fibroblasts were also more sensitive than sarcoma cells. Bovine serum albumin fraction markedly accelerated the cytotoxicity of spermine.
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Siccanin at 3 mug/ml completely inhibited the growth of Trichophyton mentagrophytes. The primary site of action of siccanin on T. mentagrophytes is succinate dehydrogenase in the terminal electron transport system. At a concentration of siccanin giving 50% inhibition of growth (0.3 mug/ml), respiration of intact cells was inhibited more strongly than any other cellular functions tested, including the syntheses of cellular ribonucleic acid, deoxyribonucleic acid, phospholipid, protein, and cell wall fractions. In addition, at the same concentration siccanin did not cause any detectable damage in the permeability of the cells. Furthermore, the oxidation of succinate in mitochondrial preparation is more sensitive to the antibiotic than respiration in intact cells. Oxidation of other substrates tested was less sensitive to siccanin than that of succinate. The antibiotic inhibited both phosphorylation and oxidation, without causing changes in the P:O ratio. Siccanin at 0.03 mug/ml, which caused 50% inhibition of succinate oxidation in mitochondria, had effect neither on the exchange reaction between inorganic phosphate (P(i)) and adenosine triphosphate (ATP) nor on that between adenosine diphosphate and ATP. An ATP phosphohydrolase activity was also insensitive to the antibiotic. At very high concentrations, however, the antibiotic slightly inhibited the P(i)-ATP exchange reaction. From those results, it was concluded that siccanin inhibits fungal growth by inhibiting the respiratory electron transport system.
Cells of Escherichia coli W3110 and its thymineless mutant, both of which are colicin E2 sensitive, were treated with colicin E2, and then converted to spheroplasts. These spheroplasts seemed to be more stable than those from untreated cells; suspensions of spheroplasts of untreated cells were lysed spontaneously and the turbidity was reduced by approximately 45% on incubation with ethylenediaminetetraacetic acid-lysozyme, whereas suspensions of spheroplasts of colicin E2-treated cells showed 25% reduction in turbidity. This change was irreversible and 5 min of treatment with colicin E2 at 37 C was necessary for stabilization. This process was inhibited by 2,4-dinitrophenol or streptomycin. Cells harboring the colicin E2 factor were not affected by treatment in this way with colicin E2. Alteration of composition of phospholipids was not observed.
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A routine prenatal sonographic examination at 36 weeks' menstrual age revealed a solid and slightly inhomogeneous soft-tissue tumor on a fetus's left upper arm. The mass in the left triceps brachii muscle measured 8 x 7 x 5 cm at birth. Because of progressive flexion contracture of the left elbow joint, at 2 months of age the infant underwent radical resection of the tumor, sparing some muscle fibers. Light microscopic and immunohistochemical studies revealed myofibromatosis. Neither tumor nor functional disorder of the arm was evident 3 years after surgery.