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Biomedical subjects

K Koike

Publications and source records attributed to K Koike.

At least 829 records · Page 46Linked to original sources
PubMed1981

Effects of smooth muscle relaxant (aspaminol) on Ca-uptake by mitochondrial and microsomal fractions from rat uterus.

A smooth muscle relaxant, Aspaminol (1,1-diphenyl-3-piperidinobutanol hydrochloride) relaxed a KCl-depolarized rat uterus and shifted a dose response curve of CaCl2 towards higher doses. Asparminol, a teritary amine, may penetrate into the KCl-depolarized muscle cells. In order to study mechanisms for relaxation of the KCl-depolarized rat uterus by Aspaminol, effects of Aspaminol on Ca-uptake by mitochondrial and microsomal fractions from the rat uterus were studied. Aspaminol inhibited Ca-uptake by both fractions. Inhibition of Ca-uptake by the mitochondrial fraction seems to increase intracellular Ca2+. Therefore, inhibition of Ca-uptake by the mitochondrial fraction is considered to be not associated with relaxation of uterus induced by Aspaminol. Since the microsomal fraction is known to form microsacs, the microsomal fraction was used as smooth muscle models. Inhibitory effect of Aspaminol on Ca-uptake by the microsomal fraction suggest a decrease in the intracellular concentration of Ca2+ of the uterine smooth muscle relaxed under the influence of Aspaminol.

Animals↗
PubMed1981

Inhibition of Ca-movement and mechanical movement in rabbit taenia coli by a smooth muscle relaxant (suloctidil).

A smooth muscle relaxant (suloctidil) relaxed a contractile response of taenia coli to acetylcholine and noncompetitively depressed a dose response curve of Cacl2 Ca-uptake by the microsomal fraction was inhibited by suloctidil. Its noncompetitive antiacetylcholine activity and inhibitory action on Ca-uptake were not influenced by an increase of external Ca-concentration. Ca-release from the Ca-incorporated microsomal fraction was not significantly influenced by suloctidil. These results suggest that suloctidil inhibit Ca-influx noncompetitively, thus inducing smooth muscle relaxation.

Animals↗
PubMed1981

Possible mechanisms of stimulatory action of papaverine on calcium-uptake by rat uterine microsomal fraction.

Effects of papaverine and cyclic AMP on Ca-uptake by the microsomal fraction from rat uterus were studied. Papaverine (3 x 10(-5) M) potentiated Ca-uptake by the microsomal fraction in the presence of potassium oxalate. However, cyclic AMP and MIX (3-isobutyl-1-methylxanthine; 1 mM), a potent phosphodiesterase inhibitor, did not influence Ca-uptake by the microsomal fraction in the presence of potassium oxalate. Cyclic AMP in concentrations of 10(-8) to 10(-4) M did not influence Ca-uptake by the microsomal fraction in the presence of potassium oxalate. In the absence of potassium oxalate, papaverine and Aspaminol (1,1,-diphenyl-3-piperidinobutanol hydrochloride), a nonspecific smooth muscle relaxant, inhibited Ca-uptake by the microsomal fraction and cyclic AMP had no influence on this uptake. These results suggest that papaverine potentiated Ca-uptake by membranes such as sarcoplasmic reticulum, in the presence of potassium oxalate and inhibited Ca-uptake by the plasma membrane-derived vesicles in the absence of potassium oxalate. These results suggest that relaxation of smooth muscle by papaverine is related to a cyclic AMP-independent mechanism as well as to a mechanism mediated via cyclic AMP.

Animals↗
PubMed1981

The TC double socket above-knee prosthesis.

The conventional total contact suction AK prosthesis presents several disadvantages, such as difficulty in wearing the socket in a sitting position, difficulty in obtaining a favourable disposition of the stump soft tissues in the socket and difficulty in avoiding stump perspiration problems. In an attempt to solve these disadvantages, a new AK prosthesis with a thermoplastic double socket was developed at the Tokyo Metropolitan Rehabilitation Center for the Physically and Mentally Handicapped. The double socket is composed of an external socket attached to the lower parts and a detachable internal socket, and appears to solve all the disadvantages of the conventional prosthesis. This prosthesis is called the TC prosthesis, and abbreviation for the Tokyo Metropolitan Rehabilitation Center. The first model of this prosthesis, (TC-1) has a metal valve. A new rubber sheet valve was developed to solve several disadvantages of the metal valve in the TC-2 prosthesis. Since November 1978 the TC-1 has been fitted to 295 AK amputees, including 9 bilateral AK amputees, and since March 1980, 145 AK amputees have received the TC-2, including 6 bilateral amputees. Satisfactory results have been obtained with both prostheses.

Amputation Stumps↗
PubMed1980

Nucleotide sequence of a cloned fragment of rat mitochondrial DNA containing the replication origin.

The nucleotide sequence was determined for the 717 bp HapII subfragment (HapEcoA5) of the EcoRI-A fragment of rat mitochondrial DNA, which contains the heavy-strand replication origin. Analysis of the heavy-strand initiation segments released from the D-loop molecules has revealed that some 5'-ends of these initiation segments are linked to ribonucleotide(s) and are heterogeneous. Sequence analysis of the 5'-end portion of the initiation segment indicated that one of the start points of the deoxyribonucleotide polymerization corresponds to the 425th bp on the HapEcoA5. Two-fold rotational symmetry and palindrome structures, and a G-cluster sequence around the start point have been discussed in connection with unidirectional replication.

Animals↗
PubMed1980

Subcellular action of Neocarzinostatin. Intracellular incorporation, DNA breakdown and cytotoxicity.

The subcellular site of action of a proteinaceous antitumor antibiotic neocarzinostatin (NCS) was studied using normal human lymphocytes, Epstein-Barr virus transformed lymphoblastoid cells, osmotically burst lymphoblastoid cells, and colicin E1 plasmid DNA. The rate of DNA strand break in these different types of DNA was found to be in the following order: Colicin DNA > burst cell DNA > lymphoblastoid cell DNA > normal lymphocyte DNA. Furthermore, fluorescence microscopy revealed that lymphoblastoid cells incorporated more fluorescein isothiocyanate labeled NCS than normal cells. High uptake of NCS in lymphoblastoid cells coincided with a high killing rate; low uptake of NCS in lymphocytes resulted in very little cell killing. Uptake velocity using fluorescein diacetate (FDA) also showed that the lymphoblastoid cells exhibited a higher uptake of FDA coinciding with a higher killing rate. The cell killing activity of NCS appears to be closely associated with the rate of intracellular uptake of NCS and subsequent direct degradation of DNA by the drug. This notion is reinforced by the reported finding that the dose required for DNA strand scission is only about 1/100 of that for the inhibition of cap formation. Thus DNA strand scission, rather than the cell membrane, appears to be the primary target of NCS. Enhanced incorporation of many substances is commonly observed upon transformation of cells by viruses, and our present results may provide an important clue toward the explanation of the selective toxicity toward tumor cells of NCS.

Antibiotics, Antineoplastic↗
PubMed1980

Effects of nonspecific smooth muscle relaxants on calcium-uptake by microsomal fraction and their inhibitory action in rabbit taenia coli.

Effects of nonspecific smooth muscle relaxants, papaverine and Aspaminol (1,1-diphenyl-3-piperidinobutanol hydrochloride) on Ca-uptake by a microsomal fraction and mechanical activity in the rabbit taenia coli were studied. Papaverine which inhibits cyclic AMP phosphodiesterase increased Ca-uptake by the microsomal fraction in a concentration of 10(-5) M but not in a concentration of 10(-4) M. Potentiation of Ca-uptake by papaverine is considered to be due to the increase of cyclic AMP as the results of the inhibition of phosphodiesterase. Aspaminol which is found to have little inhibitory action on phosphodiesterase activity inhibited Ca-uptake by the microsomal fraction. This inhibition by Aspaminol was abolished by the increase of Ca-concentration in the reaction medium. Non-competitive antihistaminic activity of Aspaminol was considerably reduced by an increase of external Ca-concentration, while the increase of external Ca-concentration slightly decreased antihistaminic activity of papaverine. Furthermore, contraction of KCl-depolarized taenia coli induced by CaCl2 was inhibited competitively by Aspaminol and noncompetitively by papaverine. These results suggest that Aspaminol competes with Ca ions at a surface site of muscle membrane concerned with Ca-uptake process, thus decreasing the supply of Ca ions to the contractile elements and that papaverine may have inhibitory actions on Ca-uptake by the microsomal fraction in addition to stimulatory action which seems to be mediated through cyclic AMP. These actions on Ca-uptake may induce smooth muscle relaxation.

Action Potentials↗
PubMed1980

[Effect of anti-human alpha-fetoprotein serum on human endodermal sinus tumor transplanted in nude mice (author's transl)].

The effects of horse anti-human alpha-fetoprotein (AFP) immunoglobulin (IgG) on growth, serum AFP concentration and histopathology of human endodermal sinus tumor serially xeno-transplanted in nude mice were examined. Anti-AFP IgG given in amounts sufficient to neutralize the serum AFP secreted by the tumor moderately reduced tumor size and significantly decreased the serum AFP levels of treated nude mice. On histopathologic examination, spindle shaped tumor cells of reticular pattern often fell into the state of necrosis. But little change was observed on the cells consisting of both solid patterns and Schiller-Duval bodies. With a growth rate of re-transplanted tissues respectively, which were obtained from both antibody administrated and control tumors, no disparity was found between two groups. Indeed this result is preliminary report, but inhibitory effects of anti-AFP IgG against tumor growth and AFP producing ability of endodermal sinus tumor xeno-transplanted in nude mouse is hopeful to apply these data on clinical cancer immunochemotherapy.

Animals↗