Biomedical subjects
N Shimada
Publications and source records attributed to N Shimada.
[Electromyographic study of small intestinal motility after jejunotomy].
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[Infectious erythema and hydrops fetalis].
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[ECMO (extracorporeal membrane oxygenation)].
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[A case of pseudolymphoma of the lung with cough and fever].
This case report presents a 48-year-old woman who had been suffering from cough and fever for 5 years. A large mass in the right lung was pointed out. Even after various examinations, we couldn't resolve the difficult diagnostic problems involved, but it was clear that there were no signs of a malignant tumor. We suspected a large benign tumor or pulmonary sequestration. Right lower lobectomy was performed and histological examinations of the resected tumor revealed lymphoproliferative disorder. Microscopic examinations of the specimen disclosed monotonous lymphoid cells proliferation (small to medium size) without definite lymph follicles or germinal centers. Lymph follicles were clearly demonstrated with the immunoperoxidase method. These findings were interpreted to be consistent with what has been recently called pseudolymphoma of the lung and prompted discussions on the reasonableness of criteria for the diagnosis of various pseudolymphoma and effective immunological examinations for the clarification of the etiology.
[Application of NST (non-stress test) to detect low risk class 3].
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[Extracellular purine catabolites and tissue nucleotides and purine catabolites during progression and recovery of ischemia].
During progression and recovery of ischemia, extracellular purine catabolites were measured and compared with purine catabolites and adenine nucleotide levels in the tissue. Ischemia was induced by bilateral occlusion of the common carotid arteries in gerbil. Extracellular purine catabolites were sampled by in vivo brain microdialysis technique, and tissue adenine nucleotides and purine catabolites were extracted from in situ frozen and lypholized brain tissue. These metabolites were measured with simple method of isoclatic condition by HPLC system. Ischemia depleted tissue ATP and ADP, whereas AMP and purine catabolites accumulated strikingly. In parallel, extracellular purine catabolites increased as consecutive degradation on the biochemical metabolic pathway in the same animal. Levels of tissue ATP and adenosine normalized in the recovery phase of ischemia immediately. However, extracellular purine catabolites during the recovery are much higher than those during the progression of ischemia. These data indicated extracellular high levels of purine catabolites during the ischemic insult, and especially adenosine as neuromodulator which may turn off spontaneous neuronal activity and exert antiepileptic effects during the recovery rather than the progression of ischemia.
Membrane-associated nucleoside diphosphate kinase from rat liver. Purification, characterization, and comparison with cytosolic enzyme.
Previous studies from this laboratory have proposed that membrane-associated nucleoside diphosphate kinase (m-NDP kinase) may play a role in regulation of adenylate cyclase by channeling GTP, an essential cofactor of adenylate cyclase regulation, into GTP-binding protein (Gs) in a hormone-dependent manner. To understand the true role of m-NDP kinase, in the present study, the m-NDP kinase was solubilized and purified to apparent homogeneity from rat liver purified plasma membranes and characterized in comparison with the cytosolic enzyme purified from the same tissue (s-NDP kinase). Some physical properties determined were: molecular weight (monomer), 18,300; sedimentation coefficient (s20,w), 6.2 S; isoelectric point (pI), 6.0. These values and kinetic parameters of the m-NDP kinase were almost identical to those of the s-NDP kinase whose characteristics were more extensively studied. A peptide mapping study of the 125I-labeled m- and s-NDP kinases gave essentially identical patterns. Polyclonal antibodies against the s-NDP kinase, which also cross-reacted with the m-NDP kinase, were prepared. Immunoblotting studies with the affinity-purified antibodies revealed that the monomer molecular weight of the purified m- and s-NDP kinases was identical to the values of unpurified enzymes present in membranes and crude extract. These results demonstrate that the purified m-NDP kinase underwent no remarkable modification during solubilization and purification, and that the m- and s-NDP kinases are quite similar in protein structure, if at all different. The physiological relevance of the m-NDP kinase in relation to the adenylate cyclase system is discussed.
Direct interaction between membrane-associated nucleoside diphosphate kinase and GTP-binding protein(Gs), and its regulation by hormones and guanine nucleotides.
In previous studies we have proposed that the membrane-associated nucleoside diphosphate kinase (m-NDP kinase) may play a role as a GTP channeling machinery for adenylate cyclase regulation by hormones. In this study, whether the m-NDP kinase has a direct interaction with the component (GTP-binding protein (Gs)) of the glucagon- and beta-adrenergic agonist-sensitive adenylate cyclase systems in rat liver membranes was examined by extraction with octylglucoside, followed by immunoprecipitation by affinity-purified monospecific anti-NDP kinase antibodies. The results demonstrated that the m-NDP kinase and the Gs were extractable as a complexed form and that the complex formation was reversibly regulated, through cell surface receptors, by hormones which had an ability to cause activation of the rat liver adenylate cyclase. Also, it was suggested that guanine nucleotides rather than hormones were primary regulators of the m-NDP kinase-Gs interaction. These results were discussed in relation to the regulatory cycle of the Gs of adenylate cyclase system.
Infiltrating ductal carcinoma developing within cystosarcoma phyllodes--a case report.
Malignancy in cystosarcoma phyllodes is uncommon and often confined to the stromal element. An extremely rare case of infiltrating ductal carcinoma developing within the stroma of cystosarcoma phyllodes is reported herein. A breast tumor with a diameter of 15 cm, which was diagnosed as cystosarcoma phyllodes, was excised from the right breast of a 47-year old woman. The histopathological examination revealed that hyperplastic ductal epithelial cells with dark cytoplasm and enlarged hyperchromatic nuclei were infiltrating the stroma. Thus, a diagnosis of ductal carcinoma within cystosarcoma was made. Subsequently, a standard radical mastectomy was performed. No recurrence or metastasis has been observed over the post-operative period of 5 years and 6 months.
Selective inhibition of human cytomegalovirus replication by a novel nucleoside, oxetanocin G.
A novel nucleoside with an oxetanosyl-N-glycoside has been recently isolated from a culture filtrate from Bacillus megaterium and named oxetanocin A (N. Shimada, S. Hasegawa, T. Harada, T. Tomisawa, A. Fujii, and T. Takita, J. Antibiot. 39:1623-1625, 1986). In this study, we evaluated the antiherpesvirus activity of oxetanocin A and its derivatives and found that 9-(2-deoxy-2-hydroxymethyl-beta-D-erythro-oxetanosyl)guanine (OXT-G) was very potent and selective in inhibiting the replication of human cytomegalovirus (HCMV) in vitro. The median effective concentration for HCMV strain AD169 was 1.0 microgram/ml, and that for herpes simplex virus type 2 strain 186 was 3.5 micrograms/ml. The selectivity index, based on the ratio of the median inhibitory concentration for cell growth of human diploid fibroblasts to the median effective concentration for HCMV plaque formation, was more than 300. The synthesis of HCMV-induced late polypeptides such as the 150,000-molecular-weight capsid and the 68,000-molecular-weight major matrix proteins was strongly suppressed when OXT-G (5 micrograms/ml) was added to the cultures at the beginning of infection. At this concentration of OXT-G, the amount of HCMV DNA detected in the drug-treated infected cells was less than 1/10 of that detected in the infected control cells. The results suggest that the mode of action of OXT-G is inhibition of viral replication by impairing the viral DNA synthesis.
Mode of action of deoxypheganomycin D on Mycobacterium smegmatis ATCC 607.
Deoxypheganomycin D, a specific inhibitor of mycobacteria, inhibits the growth in vitro of Mycobacterium smegmatis ATCC 607 (M. 607) bacteriostatically at concentrations as high as 7 X 10(-5) M. It shows no cross-resistance to paromomycin, capreomycin, viomycin, streptothricin, kanamycin and streptomycin. Deoxypheganomycin D at 2.8 X 10(-7) M where the cell growth of M. 607 is only partially inhibited does not significantly inhibit DNA, RNA or protein synthesis but leads to marked decrease (13% of control) in [14C]glycerol-derived radioactivity in cell-walls. In the presence of 7 X 10(-6) M deoxypheganomycin D, the influx of leucine but not thymidine is affected while the reverse is true with efflux. The data suggest that the effect of deoxypheganomycin D on M. 607 may be related to both the cell membrane and specific mycobacterial lipid like components of the cell-wall.
[Determination of anti-ATLA antibody in plasma].
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[Prostaglandin metabolism in glomeruli from streptozotocin diabetic rats and glomerular mesangial cells].
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[Fetal chylothorax (congenital chylothorax)].
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[Application of hysteroscopy to CVS (chorionic villi sampling)].
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[Midwifery education of the future].
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[Expectant mothers and seat belts].
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