Biomedical subjects
Publications and source records attributed to S Imada.
A rare case is reported of an osteoma protruding into the pterygomandibular space from the lateral pterygoid plate of the sphenoid bone. The procedure of the diagnosis and treatment is described. In this case, computed tomography (CT) was the most useful in making a differential diagnosis. That the pulling force of the medial pterygoid muscle might be a causative agent in the growth of this osteoma is considered.
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Cell surface proteins and glycoproteins of the CHO-K1 clone of Chinese hamster ovary cells were radiolabeled by surface-specific reactions as well as by metabolic incorporation of glycoprotein precursors. After the proteins were separated by two-dimensional gel electrophoresis, they were quantified according to the amount of radioactivity which was associated with individual proteins spots. A glycoprotein of 133,000 daltons (P133-11) wa found to increase severalfold by the elevation of the cytoplasmic level of adenosine 3':5'-cyclic monophosphate. In this paper, we report that the increase of P133-11 was more efficient in dense cultures than in sparse cultures. The use of conditioned medium or frequent medium changes during the treatment with the cyclic nucleotide did not influence the efficiency of the increase of the glycoprotein, indicating that the enrichment or exhaustion of diffusible materials was not responsible for this density-dependent phenomenon. The same conclusion was drawn from an experiment in which the amount of P133-11 was compared between homogeneously plated sparse cultures and cultures containing the same number of cells in the form of colonies with well contacted cells at an average density of 400 cells/colony. The increase of the protein was higher in the latter type of cell cultures. We, therefore, propose that the interaction of surface components upon cell-cell contact plays a role in the expression of P133-11 surface glycoprotein.
Surface expression of a membrane glycoprotein of 135,000 molecular weight (P135) was inducible by adenosine 3',5' -cyclic monophosphate in Chinese hamster ovary cells, CHO-K1 clone. Cells were cultured in the presence or absence of cyclic AMP derivatives, chemicals influencing cytoplasmic cyclic AMP levels, or inhibitors of protein or RNA synthesis. Surface proteins wre radiolabeled by a lactoperoxidase-catalyzed iodination reaction and analyzed by two-dimensional polyacrylamide gel electrophoresis. Surface expression of P135 increased 3---5-fold inthe presence of N6,O2' -dibutyryl cyclic AMP or 8-parachlorophenylthio cyclic AMP. Induction was also observed after treatment with prostaglandins E1 and F2 alpha, but not with sodium butyrate. Phosphodiesterase inhibitor, Roche compound Ro20-1724, enhanced the effect of N6,O2' -dibutyryl cyclic AMP. Metabolic incorporation of [35S]methionine into P135 was increased by N6,O2' -dibutyryl cyclic AMP. The induction was sensitive to inhibitors of protein and RNA biosynthesis. These results are consistent with a proposal that cyclic AMP controls the synthesis of this protein. Metabolic incorporation of a radioactive precursor suggested that P135 was a glucos-amine-containing glycoprotein. P135 appeared to be strongly associated with cell membrane because it was resistant to extraction of plasma membrane by cole 0.1 N NaOH.
Recombination frequencies among temperature-sensitive dna mutants from various laboratories were analyzed, and eleven dna mutants were found to be closely linked. They are classified as group B dna mutants, since these are closely linked with dnaB19, originally isolated and approximately mapped near leuA8 by KARAMATA and GROSS (1970). However, the dnaB19 mutation itself has relatively high recombination frequencies with the other mutations, thus, we propose to subdivide the dnaB group into two subgroups--dnaBI, including ten mutants (dna-1, dna-3, dna-5, dna-17, dna-27, dna-51, dna-60, dna-62, dna-103 and dna-134) and dnaBII, including dnaB19. The map order of dnaB and markers in the vicinity was determined to be argA-citH-citC-phoP-PhoR-polA-dnaBI-dnaBII-citF-leuA-pheA.
Cell walls from bacillus subtilis 168 were prepared by conventional methods and found to contain deoxyribonucleic acid (DNA). In transformation assays, after autolysis, it was found that two major regions of the chromosome were selectively enriched in the wall preparations. One region clustered around the replication origin and is represented by the markers purA16, ts8132, thiC5, sacA321, and hisA1. The other region included the replication terminus with representative loci metB10, citK5, gltA292, and pyrA1. All other (internal) loci which were examined showed no statistical enrichment. The two areas of enrichment were similar to but more extensive than those reported for membrane-DNA complexes. The wall preparations also contained protein and lipid, indicating a possible membrane involvement. Analyses of the cell walls revealed that the fatty acid composition of the membrane component was not typical of the for B. subtilis protoplast membranes or for lipoteichoic acids. In addition, radioiodination of cell wall autolysates, followed by gel electrophoresis and autoradiography, demonstrated the presence of proteins not readily detectable in bulk protoplast membranes or on the surfaces of intact cells. These data suggest that a unique component of the membrane and regions of the B. subtilis genome involved in DNA replication events are tightly associated with cell walls. The binding of DNA-membrane complexes to the "rigid" cell wall and the replication of the wall could be a mechanism by which the segregation of growing chromosomes occurs.
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