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Biomedical subjects

S Kondo

Publications and source records attributed to S Kondo.

At least 1,045 records · Page 58Linked to original sources
PubMed1986

Production and characterization of the extracytoplasmic portion of the human interleukin-2 receptor.

We made a mutant cDNA clone of the human interleukin-2 (IL-2) receptor by introducing a termination codon at the eighth amino acid residue upstream from the putative transmembrane region. Ltk- cells were transfected by this mutant cDNA and cell-lines secreting the extracytoplasmic portion of the IL-2 receptor were established. The artificial secretory molecule of the IL-2 receptor named "bottom-less" receptor was able to react with anti-Tac antibody and to bind IL-2. We purified the bottom-less receptor to homogeneity by affinity chromatography using an IL-2-Sepharose column. The affinity (Kd value) of the 125I-labeled bottom-less receptor to IL-2 coupled to Sepharose beads was estimated to be 4.5 microM. All these results confirm the putative membrane topology of the IL-2 receptor based on the primary structure, and suggest that the bottom-less receptor may maintain the basic structure and function of the extracytoplasmic portion of the IL-2 receptor.

Cell Line↗
PubMed1986

Cardiotoxic effects of maitotoxin, a principal toxin of seafood poisoning, on guinea pig and rat cardiac muscle.

Maitotoxin (MTX), a principal toxin of seafood poisoning, produced powerful cardiotoxic effects on guinea pig isolated left atria at concentrations of 5 X 10(-9) to 3 X 10(-8) g/ml. The MTX-induced increase in resting tension of atria was abolished by Co++, D600 or Ca++-free solution. The tissue Ca content and 45Ca uptake of guinea pig atria were increased by MTX (5 X 10(-9) to 3 X 10(-8) g/ml), and these increases were inhibited markedly by Co++. In isolated rat cardiac myocytes, irreversible contracture was produced by MTX (10(-8) g/ml), and this effect of MTX was suppressed by verapamil or Ca++-free solution. The intracellular free Ca++ concentration of isolated rat myocytes was increased greatly by MTX (10(-9) to 3 X 10(-8) g/ml). Furthermore, the myocardial cells sampled from guinea pig left atria were characterized ultrastructurally by severely overcontracted sarcomeres, swollen mitochondria, peripheral aggregation of nuclear chromatin and loss of granular glycogen, and these morphological changes were abolished by omitting Ca++ from the medium. These results suggest that MTX increases the Ca++ influx through the cardiac muscle membrane to create the Ca-overloaded state and thus caused the cardiotoxic effects.

Animals↗
PubMed1986

[A case of intussusception due to intestinal metastasis of renal carcinoma].

Adult intussusceptions due to metastatic intestinal-tumor are very rare. A 71-year-old man with an intussusception due to intestinal metastasis of renal carcinoma is reported. To our knowledge, this is the third such patient in the Japanese literature. The patient was suffered from an intestinal obstruction six months after his renal carcinoma was detected. Laparotomy was performed, revealing that he had developed a jejunojejunal intussusception due to metastasis of renal carcinoma. The early diagnosis of metastatic intestinal tumor is difficult. It is important to bear in mind that patients with malignant tumor may already have metastasis.

Adenocarcinoma↗
PubMed1985

Studies of Wakan-Yakus (traditional herbal drugs): especially on the effects of Gaiyoh (Artemisiae folium) on blood coagulation.

Wakan-Yakus (traditional herbal drugs) such as Akyoh (Glutinum), Gaiyoh (Artemisiae folium), Sanshishi (Gardeniae fructus), Kizutsu (Aurantii fructus), and Taisoh (Zizyphi fructus) were studied in relation to their effects on blood coagulation-fibrinolysis. (1) All of the water extracts of the Wakan-Yakus prolonged aPTT and PT. The potency of the effectiveness on aPTT was in the order of Gaiyoh (Artemisiae folium) greater than Kizutsu (Aurantii fructus) greater than Sanshishi (Gardeniae fructus) greater than Taisoh (Zizyphi fructus) greater than Akyoh (Glutinum). (2) Gaiyoh (Artemisiae folium) greater than Kizutsu (Aurantii fructus) greater than Akyoh (Glutinum) greater than Taisoh (Zizyphi fructus) showed the antifibrinolytic effects in this order. On the other hand, Sanshishi showed the accelerating effect on fibrinolysis. (3) The inhibition modes of both thrombin and plasmin by Gaiyoh (Artemisiae folium) were shown to be competitive on Lineweaver-Burk plot. (4) Gaiyoh (Artemisiae folium) was gel-filtered on Sephadex G-25 column (1.5 X 90cm) equilibrated with distilled water at room temperature. Five fractions were obtained, and in the first to fourth fraction, strong anticoagulant effects on aPTT and PT were observed. We pooled first and second to make fraction I, and make fraction II from peak 3. The recovery rate was 4.2% by weight, and 36.7% by inhibition activity, and specific activity on the basis of inhibition to aPTT was 34.8% U/mg in the case with fraction II. Fraction I was found to be the same characteristically on blood coagulation. Fraction II was further purified by Sephadex LH-20 column (1.5 X 80 cm) at room temperature. Three fractions (Fraction IIa, IIb, IIc) were obtained, and the strong inhibitory effects was observed on both aPTT and PT in each fraction. The first fraction (fraction IIa) showed the strong inhibitory effect on aPTT, and the heightened specific activity with 17.6% as the recovery rate.

Animals↗
PubMed1985

Oral administration of factor VIII concentrate preparation in von Willebrand's disease.

We investigated on how to effectively administer orally factor VIII preparation to two patients with von Willebrand's disease as volunteers, and the following results were obtained: Bleeding time and aPTT were shortened, but no change of PT was observed. Factor VIII:C increased slightly, but no significant increase was observed in factor VIIIC:Ag. The recovery of factor VIII:C was 19-40%. Factor VIIIR:Ag increased slightly, but no changes of factor VIIIR:RCo were observed. In the Ristocetin induced platelet aggregation (1.5 mg/ml of ristocetin), the collected aggregation abilities were not clear. The factor VIII concentrate preparations, entrapped with liposome, were absorbed from the intestines.

Administration, Oral↗
PubMed1985

Determination of nifedipine in human plasma by high-performance liquid chromatography with electrochemical detection.

A rapid, accurate and sensitive high-performance liquid chromatographic assay was developed for the determination of nifedipine in human plasma. A toluene extract of an alkalinized plasma sample was chromatographed on a reversed-phase column with electrochemical detection at +0.95 V. The recovery of nifedipine from plasma was about 100%. The detection limit for nifedipine in plasma was 2 ng/ml using 0.5 ml of sample. The assay gave a linear response over the concentration range 5-400 ng/ml in plasma. The coefficients of variation from 9.6 to 191.0 ng/ml varied between 5.2 to 1.0% and the accuracy did not exceed 3.0%. Photodegradation products and metabolites of nifedipine did not interfere in the analysis. This method allowed the behaviour of nifedipine in humans to be studied.

Administration, Oral↗
PubMed1985

Nucleotide sequence of mouse IL-2 receptor cDNA and its comparison with the human IL-2 receptor sequence.

We have cloned cDNA encoding the mouse interleukin-2 (IL-2) receptor from a murine T cell line, CTLL using human IL-2 receptor cDNA as probe. COS 7 cells transfected with the cDNA expressed the antigen recognized by the monoclonal antibody against the murine IL-2 receptor. The cDNA identified 4 species of mRNA (4.5, 3.5, 2.2 and 1.5 kb) of the mouse IL-2 receptor in CTLL cells. Difference in the length of mRNA seems to be ascribed to the variable length of the 3' untranslated sequence. Total nucleotide sequence (approximately 1400 bp) of this cDNA was determined and compared with the human receptor. The nucleotide and amino acid sequences of the IL-2 receptor are 70% and 60%, respectively, homologous in average between the two species. The comparison has revealed several conserved regions localized to particular exons such as transmembrane and cytoplasmic portions, suggesting that these regions are important for receptor function and its regulation.

Amino Acid Sequence↗
PubMed1985

RNA tumor virus in human thymomas and thymus hyperplasias.

Human thymomas and thymus hyperplasias were examined for retroviruses. Most of these patients were complicated by systemic immunological diseases such as myasthenia gravis and pure red cell aplasia. The thymus cells were co-cultured with allogenic B cells or peripheral blood lymphocytes (PBL) pretreated with mitomycin C. Retrovirus-like particles were demonstrated in cultured thymus cells in all cases of thymomas and thymus hyperplasias examined by electron microscopy. In most cases, these particles were detected in thymus epithelial cells. Reverse transcriptase activity sedimenting at a density of 1.15-1.17 gm/cm3 in sucrose density gradients was eluted in the culture fluids. Retrovirus-like particles were demonstrated in human T cells infected with these particles. Antibodies to virus-infected T cells were detected in sera of the patients with thymoma and thymus hyperplasia. These results suggest that in thymomas and thymus hyperplasias, retroviruses that can be induced, following a proliferative stimulus, may be involved in the genesis of thymic disorders and in the pathogenesis of systemic immunological diseases.

Adult↗
PubMed1985

Evidence for cell-replacement repair of X-ray-induced teratogenic damage in male genital imaginal discs of Drosophila melanogaster.

Male genital imaginal discs from old (late-third-instar) larvae of Drosophila that had been X-irradiated with appropriate doses developed into severely damaged adult genitalia when implanted into old larvae, but they developed into completely normal adult genitalia when transplanted into 2-day-younger larvae. The major cause of X-ray-initiated teratogenesis in the genital disc was DNA damage because development of the genital discs of strain mei-9a with defective DNA repair was twice as sensitive as that of the wild-type strain to impairment by X-irradiation, just as larvae of this strain were twice as sensitive to killing by X-irradiation as those of the wild-type strain. Complete repair of X-ray-induced teratogenic damage in the genital discs on transplantation into young host larvae was similar in the wild-type and mei-9a strains. These results are discussed in relation to the hypothesis that repair of X-ray-induced teratogenic damage depends not on DNA repair but on replacement of damage-bearing primordial cells by healthy ones after suicidal elimination of the former.

Animals↗
PubMed1985

Enhancement by estrogen treatment of -bungarotoxin binding in fetal mouse amygdala cells reaggregated in vitro.

Dissociated amygdala cells from 17-day-old mouse fetuses were cultivated in a flask for 7 days to form aggregates. In the aggregates there developed typical synaptic structures and [125I]alpha-bungarotoxin binding capacity. An addition of estradiol (100 ng/ml) in the culture medium caused a significant increase in the toxin binding capacity. From these results it is concluded that estradiol enhances alpha-bungarotoxin binding capacity in the amygdala by exerting direct effects on the developing amygdala cells.

Amygdala↗
PubMed1985

Structures of defective P transposable elements prevalent in natural Q and Q-derived M strains of Drosophila melanogaster.

Several DNA sequences with homology to the complete 2.9-kilobase (kb) P element from a P strain in the United States were isolated and characterized from two Drosophila melanogaster strains collected on Chichi Jima, an island 1000 km south of Tokyo. Except for a missing central region and trivial unsequenced regions of 38 base pairs, the 2.1-kb element isolated from a Q strain had the same DNA sequence as that of the complete P element. Seven other elements cloned from genomic DNAs of the Q strain and a Q-derived M strain all possessed the same restriction sites as those of the 2.9-kb P element except for one deleted region in each element. The finding of sequence conservation in P elements have had a common ancestor relatively recently. Thus, it is suggested that the P element family was a recent invader of the species. By contrast, no complete P element was found in these Japanese strains so far as surveyed, indicating the possibility that P elements in the Chichi Jima population are almost all defective. The implication of this possibility is discussed in relation to the uniqueness of the population on Chichi Jima where Q strains predominate and no P strains have yet been found.

Journal Article↗
PubMed1985

Analysis of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced DNA damage in tumor cell strains from Japanese patients and demonstration of MNNG hypersensitivity of Mer xenografts in athymic nude mice.

Among 15 human tumor cell strains from Japanese patients, one strain derived from a patient with thyroid cancer showed inability to support the growth of adenovirus 5 treated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). When plated on this Mer- strain, adenovirus 5 showed 3-4 times higher sensitivity to MNNG-induced killing than when plated on any of the other 14 Mer+ tumor cell strains. Biochemical analysis showed that the Mer- strain was defective in demethylation repair of O6-methylguanine produced by MNNG treatment. The sensitivities of 12 of the 15 human tumor strains, including the Mer- strain, to MNNG were compared by measuring their colony-forming abilities. All the strains tested showed the Rem- phenotype (having higher sensitivity to MNNG-produced cell killing than normal fibroblasts). The differential killing effects of MNNG on Mer- and Mer+ tumor cells under in vivo conditions were tested using the Mer+ HeLa S3 strain and its Mer- variant. Mer+ cells and Mer- cells were implanted subcutaneously into the left and right flanks, respectively, of 10 nude mice and the next day, MNNG solution (0.25 ml at 1 mg/ml) was injected into the implantation sites of eight mice. Mer- tumor cells in six of eight treated mice showed no growth and those in the other two mice did grow, but regressed after approximately 3 weeks. In contrast, Mer+ tumor cells continued to grow in all the eight mice treated, indicating that Mer- tumor cells may be selectively inactivated by suitable therapeutic regimens with appropriate methylating drugs.

Adenoviruses, Human↗
PubMed1985

Comparison of somatic reversions between the ivory allele and transposon-caused mutant alleles at the white locus of Drosophila melanogaster after larval treatment with X rays and ethyl methanesulfonate.

Somatic reversion of strains with the ivory (wi) allele, a mutation associated with a tandem duplication of a DNA sequence at the white locus, increased with the age of larvae at the time of X-irradiation as expected from the increase in the number of target cells. In contrast, two independently isolated strains with unstable w+ loci associated with insertion of transposable elements showed higher reversion frequencies after treatment with X rays or ethyl methanesulfonate (EMS) at early larval stages than at late stages. Nevertheless, both the wi strain and the two unstable w+ strains reverted at nearly equal rates after treatment with X rays or EMS at early larval stages. Possible similarity in "hot spot" structure for the high reversibility of the two types of mutations is discussed in relation to production of presumed "mutator-type" cofactors specific to the transposon-caused mutations at early larval stages.

Alleles↗
PubMed1985

Amino acid sequences of the two kinds of regulatory light chains of adductor smooth muscle myosin from Patinopecten yessoensis.

Smooth muscle myosin from scallop (Patinopecten yessoensis) adductor muscle contains two kinds of regulatory light chains (regulatory light chains a and b), and myosin having regulatory light chain a is suggested to be suitable for inducing "catch contraction" rather than myosin having regulatory light chain b (Kondo, S. & Morita, F. (1981) J. Biochem. 90, 673-681). The amino acid sequences of these two light chains were determined and compared. Regulatory light chain a consists of 161 amino acid residues, while regulatory light chain b consist of 156 amino acid residues. Amino acid substitutions and insertions were found only in the N-terminal regions of the sequences. The structural difference between the two light chains may contribute to the functional difference between myosins having regulatory light chains a and b.

Amino Acid Sequence↗