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Biomedical subjects

K Koike

Publications and source records attributed to K Koike.

At least 811 records · Page 45Linked to original sources
PubMed1982

The density and distribution of intramembrane particles in erythrocytes from persons with muscular dystrophies.

Intramembrane particles in the freeze-fractured faces of erythrocyte membranes from persons with several different types of muscular dystrophy are examined. The density of particles in the protoplasmic face was lower than that of controls, although not at a statistically significant level. No altered pattern of aggregation of these particles was observed.

Erythrocyte Membrane↗
PubMed1982

Quantitative assessment of water content of human lung: a study on open lung biopsy specimen.

Quantitative assessments of human lung water are necessary to evaluate lung water changes, but little knowledge is available about a human "normal" lung. To determine a "normal" lung water content, pieces of lung tissue were obtained from lungs which should be resected for solitary nodular lung diseases, and the water content was assessed in terms of the ratio of extravascular lung water to blood free dry lung weight (Qw1), using the gravimetric methods. Among 152 patients who underwent open thorax surgeries for their solitary nodular lung diseases, 35 lung specimens were obtained from lungs which were free from any abnormal lesions. Since the postoperative histological examination did not reveal any pathological findings except for the solitary nodules in the resected lobes of 35 patients, the 35 pieces were also considered to be "normal". The value of Qw1 was 3.66 +/- 0.29 (mean +/- S.D.) g/g blood free dry lung. This value would serve as a reference of Qw1 in human "normal" lung.

Adult↗
PubMed1982

Effects of irradiation on the pulmonary vascular fluid and protein exchange.

In anesthetized sheep, ventilated by positive pressure, pulmonary arterial and left atrial pressures, cardiac output, and lung lymph flow (Qlym) were measured and lymph-to-plasma protein concentration ratio (L/P) was determined. For sheep were irradiated with 60Co on the bilateral lower lobes, avoiding irradiation on the heart and the caudal mediastinal lymph node. Qlym increased during and after irradiation, and reached a new steady state (160% increase), while pulmonary arterial or left atrial pressure did not change. In 4 control experiments, pulmonary hemodynamics, Qlym or L/P did not change. Therefore the increased fluid or protein flux after irradiation cannot be ascribed only to abnormal pulmonary hemodynamics. Endothelial damages seem to play a role in the increase of fluid filtration and protein permeability.

Animals↗
PubMed1981

Properties of a DNA-dependent ATPase from rat mitochondria.

A DNA-dependent ATPase has been highly purified from rat liver mitochondria and characterized. The enzyme catalyzes the hydrolysis of ATP or dATP in the presence of single-stranded DNA cofactor and a divalent cation. The Km values for ATP and dATP are 0.15 mM and 0.35 mM, respectively. The enzyme activity is highly sensitive to N-ethylmaleimide. The sedimentation coefficient of the enzyme is 8.3 S in a glycerol gradient. From this and data on Sephadex G-200 gel filtration, the molecular weight of the native enzyme was calculated to be about 190,000. All the natural single-stranded DNAs tested were equally effective for the ATPase activity, but synthetic deoxyhomopolymer poly(dC) was found to be more effective than natural single-stranded DNAs. Synthetic and natural RNAs had no effect on the activity.

Adenosine Triphosphatases↗
PubMed1981

A dual action of papaverine on calcium uptake by microsomal fraction isolated from rat uterus.

The effects of papaverine, cyclic AMP and MIX(3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor) on calcium uptake by a microsomal fraction from rat uterus were tested in the presence of 3 mM ATP. Papaverine potentiated calcium uptake in the presence of oxalate but inhibited it in the absence of oxalate. However, cyclic AMP and MIX did not influence calcium uptake, neither in the presence nor the absence of oxalate. These results suggest that calcium uptake by plasma membrane-derived vesicles in the absence of oxalate is inhibited by papaverine and that papaverine potentiated calcium uptake by the internal membranes in the presence of oxalate. They suggest also that the stimulatory action of papaverine involves a cyclic AMP-independent mechanism in addition to the mechanism via cyclic AMP.

Animals↗
PubMed1981

Nucleotide sequences of small ribosomal RNA and adjacent transfer RNA genes in rat mitochondrial DNA.

The nucleotide sequences of genes for small 12 S ribosomal RNA and two transfer RNAs (tRNAPhe and tRNAVal) and their common upstream region in cloned rat mitochondrial DNA were determined. This DNA sequence of 1709 bp extends between the HindII and HindIII cleavage sites in the EcoRI-A and EcoRI-D fragments, respectively. There is no long reading frame for protein synthesis starting from the HindIII site and extending all the way to the HindII site, or vice versa. The heavy strand was found to be the template for these RNA transcripts. The 5' and 3' ends of the 12 S ribosomal RNA gene are contiguous with the tRNAPhe and tRNAVal genes, respectively. The structural features of the two tRNA genes are significantly different from the standard prokaryotic tRNA pattern. Since similar contiguous natures of these genes in human (Crews and Attardi, Cell 19 (1980) 775; Eperon et al., Nature 286 (1980) 460) and mouse (Van Etten et al., Cell 22 (1980) 157) mitochondrial DNA have been reported, comparative studies on the structures of these genes were performed by computer analysis and the characteristic features are discussed.

Animals↗
PubMed1981

Induction of ovulation in patients with normoprolactinemic amenorrhea by combined therapy with bromocriptine and clomiphene.

Bromocriptine is known to be effective in the treatment of women with hyperprolactinemic anovulation or amenorrhea-galactorrhea. A new schedule of combined treatment with bromocriptine and clomiphene citrate was applied to 23 patients with normoprolactinemic amenorrhea who failed to respond to clomiphene alone. Ovulation was restored by treatment in 14 of these patients (60.9%), resulting in pregnancy in 3 women. Treatment resulted in immediate suppression of serum prolactin levels and a gradual increase in serum luteinizing hormone levels and estradiol levels followed by a luteinizing hormone surge. The present results indicate that bromocriptine/clomiphene combination therapy is effective in the treatment of amenorrheic patients with normoprolactinemia who do not respond to clomiphene alone, and suggest that bromocriptine restores the responsiveness of the hypothalamic-pituitary-ovarian system to clomiphene.

Adult↗