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Biomedical subjects

K Shimura

Publications and source records attributed to K Shimura.

At least 109 records · Page 6Linked to original sources
PubMed1987

Goats as natural intermediate hosts of Hammondia hammondi.

The infectivity of Hammondia hammondi (the G-8 strain) to goats was studied to determine the origin of this strain, because it was originally isolated from feces of a cat fed goat muscles. No clinical signs except fever were observed in kids after oocyst inoculation. When cat fed muscles of these kids, the cats excreted oocysts. The prepatent period was 7 to 9 days and the patent period was 6 to 12 days. From these experiments it became clear that the G-8 strain was infectious to goats. The origin of this strain is very probably the goat, which thus is one of the natural intermediate hosts of H. hammondi.

Animals↗
PubMed1987

Further evidence for importance of the subunit combination of silk fibroin in its efficient secretion from the posterior silk gland cells.

A locus responsible for the Nd-s mutation of the silkworm, Bombyx mori, has been mapped very close to or within the fibroin light (L) chain gene on the 14th chromosome (Takei, F., K. Kimura, S. Mizuno, T. Yamamoto, and K. Shimura, 1984, Jpn. J. Genet., 59:307-313). A strain of B. mori carrying the homozygous Nd-sD mutation (Nd-sD/Nd-sD; Nd-sD is allelic to Nd-s) secretes less than 0.3% of fibroin into the lumen of the posterior silk gland compared with a strain carrying the homozygous wild-type alleles (+/+). The small amount of fibroin that is secreted in the Nd-sD/Nd-sD strain consists of the heavy (H) chain only and lacks the L chain, although the L chain mRNA and the proteins that are cross-reactable with the anti-L chain serum are present in the posterior silk gland cells. In the hybrid silkworm, Nd-sD/+, the H chain derived from either the Nd-sD or + allele forms disulfide linkage with the L chain derived from the + allele and these fibroins are secreted into the lumen with an equal efficiency, but the L chain derived from the Nd-sD allele remains in the cell unbound to the H chain. Some evidence suggesting structural abnormality of the L chain derived from the Nd-sD allele is presented. These results, together with the previous results on the effect of the H chain gene-linked Nd(2) mutation (Takei, F., F. Oyama, K. Kimura, A. Hyodo, S. Mizuno, and K. Shimura, 1984, J. Cell Biol., 99:2005-2010), strongly suggest that the H-L subunit combination of silk fibroin is important for its efficient secretion.

Alleles↗
PubMed1987

A rapid and sensitive analytical procedure for human plasminogen subspecies. Combination of high-performance affinity chromatography and specific monitoring of proenzymes.

Human plasminogens specifically separated by high-performance affinity chromatography were specifically detected by a newly devised, on-line monitoring system, in which the proenzymes were activated by urokinase and plasmin activity thus generated was assayed. Presence of Lys-plasminogen as a constituent in the blood was demonstrated by both chromatographic patterns and biochemical experiments. This system made it possible to estimate rapidly not only Glu-plasminogen but also Lys-plasminogen in the plasma without any pretreatment. Its utility as a tool for clinical analysis of fibrinolytic system was suggested.

Chromatography, High Pressure Liquid↗
PubMed1987

Anemia-inducing substance (AIS) in advanced cancer: inhibitory effect of AIS on the function of erythrocytes and immunocompetent cells.

The effects of anemia-inducing substance (AIS), found in the plasma of tumor-bearing subjects, on red blood cells (RBC) and cellular immunity were examined. The results obtained may be summarized as follows: 1) The osmotic resistance and the deformability of RBC were decreased in patients with terminal cancer. 2) Normal human RBC were made less deformable and their membrane was made fragile by treatment with cachectic plasma from those patients, and these changes in physical properties were irreversible. 3) Energy metabolism in RBC was affected by AIS, that is, ATP concentration and pyruvate kinase activity in RBC were lowered and transmembrane glucose influx was suppressed. 4) AIS was removed from cachectic plasma by repeated adsorption with normal RBC, and the inhibitory effect on cellular immunity was lessened as AIS was removed. 5) AIS was detected in cachectic RBC membrane, monocytes, and tumor tissue by indirect immunofluorescence assay using rabbit anti-AIS antibody prepared by us. These observations suggest strongly that tumor-derived AIS appears in the blood of patients with terminal cancer, shows cytotoxicity to RBC and immunologically competent cells, and plays a role in the pathogenesis of cancer cachexy.

Adenosine Triphosphate↗
PubMed1986

Transposable genetic element found in the 5'-flanking region of the fibroin H-chain gene in a genomic clone from the silkworm Bombyx mori.

A transposable genetic element was found in the 5'-flanking region of the fibroin H-chain gene in one of the genomic clones from the silkworm Bombyx mori. This element, named K-1.4, is about 1 X 4 X 10(3) base-pairs long, contains an open reading frame of only 225 base-pairs and has inverted repeats of 12 base-pairs at both ends. Duplication of three base-pairs seems to have occurred when this element was integrated into the silkworm genome. About 15 copies of K-1.4 are present per haploid genome of various silkworm strains. Genomic loci of some of these elements are different among different strains or even among individual offspring of the same parents. K-1.4 is present also in the genome of Bombyx mandarina. The K-1.4-related sequences are present in some species belonging to the family Saturniidae.

Animals↗
PubMed1986

Effects of a blended Chinese medicine, xiao-chai-hu-tang, on Lewis lung carcinoma growth and inhibition of lung metastasis, with special reference to macrophage activation.

The antitumor effects of Xiao-Chai-Hu-Tang (Shosaiko-To: SHX) with or without 5-fluorouracil (5-FU) or cyclophosphamide (CY) were examined in an experimental system of lung metastasis induced by Lewis lung carcinoma in C57BL/6crSlc mice. Lewis lung carcinoma cells were implanted into the footpads of the mice. Ten days later, the implanted tumors were surgically removed. The effects of SHX were evaluated by the number of lung surface nodules present 14 days after removal of the implanted tumor. The administration of SHX, p.o. (300 mg/kg X 2/day X 10) caused the antimetastatic effect. Therapy with SHX plus 5-FU or CY significantly inhibited the development of lung metastases. The number of peritoneal macrophages and the degree of the binding of C3 cleavage products (C3b) to macrophages were enhanced in the mice treated with SHX. Lung metastases were inhibited by the i.v. administration of peritoneal macrophages activated with SHX, p.o. These findings raise the possibility that SHX may have clinical value in the prevention of cancer metastasis.

Animals↗
PubMed1985

Separation of human Glu-plasminogen, Lys-plasminogen and plasmin by high-performance affinity chromatography on Asahipak GS gel coupled with p-aminobenzamidine.

Human Glu-plasminogen, Lys-plasminogen and plasmin were effectively separated by high-performance affinity chromatography. The affinity adsorbent was prepared by using a micro-particulate polyvinyl alcohol gel (Asahipak GS-gel) as the supporting material and p-aminobenzamidine as the specific ligand. All of the active enzyme and proenzymes were adsorbed. Glu-plasminogen was eluted by changing the pH of the eluent and Lys-plasminogen by using an eluent containing 6-amino-hexanoic acid. This affinity adsorbent recognized the difference between these proenzyme species. For the elution of plasmin, addition of urea was necessary. Plasmin may have been adsorbed through a two-site interaction with the adsorbent. All proteins were eluted as sharp peaks and the time required for one cycle was about 1 h. Fluorimetric detection of eluted protein and on-line assay of enzyme activity using a fluorigenic substrate made it possible to analyse microgram amounts of proteins specifically.

Animals↗
PubMed1985

High-performance affinity chromatography of trypsins on Asahipak GS-gel coupled with p-aminobenzamidine.

An adsorbent for high-performance affinity chromatography of trypsins was prepared, based on a micro-particulate polyvinyl alcohol gel for high-performance liquid chromatography, Asahipak GS-gel. After the hydroxyl groups had been activated with 1,1'-carbonyldiimidazole, 6-aminohexanoic acid was coupled as a spacer, then p-aminobenzamidine, a specific ligand for trypsin-family enzymes, was immobilized on the spacer. Fluorometric detection of eluted protein and on-line assay of enzyme activity using a fluorogenic substrate, peptidylmethylcoumarylamide, made it possible to attain very high sensitivity. Microgram amounts of bovine trypsin and Streptomyces griseus trypsin could easily be analyzed in a short time (less than 1 h).

Adsorption↗
PubMed1985

Molecular cloning of the fibroin light chain complementary DNA and its use in the study of the expression of the light chain gene in the posterior silk gland of Bombyx mori.

Fibroin light chain (L-chain) mRNA (mol. wt 4.0 X 10(5) daltons) was purified from the posterior silk gland of the silkworm, Bombyx mori (J-131 strain). Double-stranded complementary DNA was synthesized and inserted into the PstI site of pBR322 employing the oligo(dC)-oligo(dG) tailing method. Several recombinant plasmids containing the inserts of about 800 base pairs were isolated. Hybridization-translation assay demonstrated that these clones hybridized specifically with the fibroin L-chain mRNA. One of these clones (pLA23) was used as a probe to investigate relative concentrations of the fibroin L-chain gene and mRNA in the posterior silk glands at different stages of late larval development.

Animals↗
PubMed1985

Affinity gel titration: quantitative analysis of the binding equilibrium between immobilized protein and free ligand by a continuous titration procedure.

A new method, called affinity gel titration, for analyzing the specific interaction between an immobilized protein and a ligand molecule is presented. Only one or two experimental runs permit the determination of not only the equilibrium constant but also the amount of immobilized protein. A suspension of the immobilized protein on agarose gel beads is confined in a constant volume mixing cell. A solution of a specific ligand molecule of constant concentration is introduced into the cell so that its concentration in the cell increases continuously (as in a mixing chamber for forming a convex gradient). The correlation between the concentration of the ligand in the efflux and the cumulative volume of the efflux can be analyzed either by regression to a theoretical curve or by a graphical method. Specific binding of p-aminobenzamidine to immobilized Streptomyces griseus trypsin was studied by this method. The dissociation constant and the amount of active trypsin were determined. The values obtained were in good agreement with the inhibition constant obtained by a kinetic experiment with free trypsin and with the amount of active site measured by using p-nitrophenyl p'-guanidinobenzoate, respectively. A single run of the titration procedure could be completed within 1 h.

Autoanalysis↗
PubMed1985

Sequence polymorphisms around the 5'-end of the silkworm fibroin H-chain gene suggesting the occurrence of crossing-over between heteromorphic alleles.

Nucleotide sequences around the 5'-ends of the silkworm fibroin H-chain genes of the three strains, Nd(2), J-139, and F1(Gunka X Hoshun), of Bombyx mori were determined. Comparison of the sequences among these strains and the sequences reported previously for the two other strains, F1(Gunpo X Shugyoku) and Daizo, indicates that polymorphisms are present in the 5'-flanking and intron regions and that each region has at least two sequence variants independent of each other. These results suggest that crossing over between the heteromorphic H-chain alleles has occurred during the breeding of these strains.

Alleles↗
PubMed1985

Effects of insecticidal carbamates on brain acetylcholine content, acetylcholinesterase activity and behavior in mice.

Mice showed no toxic signs after a single injection of o-sec-butylphenyl methylcarbamate (BPMC, 10 mg/kg) or 2-isopropoxyphenyl-N-methylcarbamate (propoxur, 2 mg/kg). Each dose of BPMC or propoxur caused an increase in acetylcholine content and a decrease in acetylcholinesterase activity in the forebrain of mice at 10 min, followed by an almost complete recovery in the content at 60 min. Spontaneous motor activity was depressed 10 min after and recovered 60 min after, injection of BPMC or propoxur. Neither rotarod performance nor rectal temperature showed any change after injection of BPMC or propoxur. Spontaneous motor activity may therefore be a simple method for assessing small changes in the cholinergic system.

Acetylcholine↗
PubMed1985

Detection of mucosal and serum antibodies specific for the capsular polysaccharide of Haemophilus influenzae type b by enzyme-linked immunosorbent assay.

A sensitive enzyme-linked immunosorbent assay (ELISA) with rough-surfaced glass beads used as the solid phase was developed for detection of IgG, IgM, and IgA antibodies to Haemophilus influenzae type b capsular polysaccharide (HITB-CP). A successful method for indirect coating of glass bead surfaces with HITB-CP, and parameters affecting the specificity and sensitivity of the assay are described. This ELISA system proved to be 100 times as sensitive as the standard indirect fluorescent-antibody assay. The assay was applied to the measurement of antibodies to HITB-CP in serum and nasal secretions and proved to be a useful tool in the evaluation of immunological response to HITB infection.

Animals↗