Biomedical subjects

K Kishimoto

Publications and source records attributed to K Kishimoto.

At least 19 recordsLinked to original sources

PubMed1996

SFA-2, a novel bZIP transcription factor induced by human T-cell leukemia virus type I, is highly expressed in mature lymphocytes.

A novel cellular gene, SFA-2, was isolated by differential hybridization of a cDNA library, using probes obtained from an adult T-cell leukemia cell line in comparison with normal CD4+ T cells and MOLT-4 cell line. The mRNA of the SFA-2 gene is approximately 0.9-kb in size and encodes a protein of 125 amino acids, containing a basic region-leucine zipper DNA-binding domain. The N-terminal region of SFA-2 is rich in serine and contains a consensus sequence for casein kinase II phosphorylation. The SFA-2 gene was strongly expressed in mature T and B lymphocytes, and was up-regulated after transformation by human T-cell leukemia virus type I. The SFA-2 did not homodimerize efficiently but formed heterodimer preferentially with c-Jun. The SFA-2/c-Jun heterodimer bound preferentially to the AP-1 and CRE sites.

Amino Acid Sequence↗

PubMed1996

Suicide inactivation of porcine leukocyte 12-lipoxygenase associated with its incorporation of 15-hydroperoxy-5,8,11,13-eicosatetraenoic acid derivative.

Two isozymes of arachidonate 12-lipoxygenase, platelet-type and leukocyte-type, which were distinguished by their substrate specificities and primary structures, were investigated with reference to 'suicide' inactivation. Upon reaction with arachidonic acid the leukocyte-type enzyme was inactivated rapidly during the catalysis, whereas the platelet-type enzyme did not show such a rapid inactivation. The two 12-lipoxygenase isozymes were incubated with various hydroperoxy and hydroxy products from arachidonic acid. (15S)-Hydroperoxy-5,8,11,13-eicosatetraenoic acid (15-HPETE) was found to be a unique substrate of the leukocyte-type 12-lipoxygenase as follows. (1) 15-HPETE was an active substrate for porcine leukocyte 12-lipoxygenase, and converted anaerobically to a 14,15-epoxy compound (14,15-leukotriene A4). (2) A rapid inactivation of the enzyme was observed within 2 min upon aerobic and anaerobic incubations with 15-HPETE. (3) 15-HPETE was rapidly incorporated into the enzyme in a nearly equimolar amount under both aerobic and anaerobic conditions. (4) Several findings suggested a covalent binding of 15-HPETE or its derivative to the enzyme. (5) Such a rapid and stoichiometric incorporation of 15-HPETE was not observed with the platelet-type 12-lipoxygenase. On the basis of these findings we presumed that 15-HPETE was transformed to 14,15-leukotriene A4, which was covalently bound to the leukocyte-type 12-lipoxygenase leading to the suicide inactivation of the enzyme.

Animals↗

PubMed1996

Serum levels of soluble interleukin-2 receptor in patients with perennial allergic rhinitis before and after immunotherapy.

BACKGROUND: Interleukin-2 receptor (IL-2R) exists in soluble form in sera, and the rate of release of the soluble form of IL-2R (soluble IL-2R) reflects T cell activation in vivo. Since T lymphocytes play a central role in respiratory allergic disorders, the measurement of serum levels of soluble IL-2R may be useful in analyzing the disease state of allergic disorders. OBJECTIVE: To investigate the serum concentrations of soluble IL-2R in 48 patients with perennial allergic rhinitis and 14 nonatopic healthy controls, with special reference to the possible changes following long-term immunotherapy. METHODS: This retrospective study included 48 patients who had had variable periods of long-term immunotherapy with Dermatophagoides farinae extracts. The duration of immunotherapy ranged from 5 to 15 years. Serum samples were collected twice from each patient, before the initiation of immunotherapy and at the time of clinical assessment of immunotherapy. All the serum samples were simultaneously used for determination of soluble IL-2R concentrations, by the use of an enzyme-linked immunosorbent assay. To serve as controls, 14 nonallergic subjects of the same age range and sex were chosen. RESULTS: Patients with allergic rhinitis before immunotherapy had significantly higher serum levels of soluble IL-2R than nonatopic subjects. Elevated serum levels of soluble IL-2R decreased significantly following immunotherapy and the serum levels of soluble IL-2R in patients with allergic rhinitis after immunotherapy were not statistically different from those of nonatopic subjects. In addition, the percent decrease in serum soluble IL-2R correlated significantly with the duration of immunotherapy. CONCLUSIONS: Hyperactivity of helper T cells of atopic patients is altered after long-term immunotherapy, and such immunoregulatory changes could be theoretically involved in the mechanisms of immunotherapy.

Adolescent↗

PubMed1996

Serum level of interleukin-4 in patients with perennial allergic rhinitis during allergen-specific immunotherapy.

Interleukin-4 (IL-4) may play a central role in the IgE synthesis system, the development of Th-2-like cells, and co-ordination as well as the persistence of airway inflammatory process in allergic disorders. Therefore, IL-4 plays a key role in airway allergic disorders. This study aimed at investigating the serum concentrations of IL-4 in patients with perennial allergic rhinitis, with special reference to the possible changes and the clinical relevance following long-term immunotherapy. The study has demonstrated that the serum level of IL-4 in allergic rhinitis patients before immunotherapy is significantly higher than that in non-atopic individuals. However, the serum IL-4 level in allergic rhinitis patients did not decrease following anti-allergic medications but significantly decreased following immunotherapy. The percentage decrease in IL-4 was correlated significantly with the percentage decrease in specific IgE antibodies following long-term immunotherapy. Immunotherapy also significantly decreased specific IgE anti-bodies, but this reduction in specific IgE antibodies was not significantly correlated with the clinical improvement. In contrast, the percentage decrease in serum IL-4 was significantly correlated with the percentage decrease in symptomatic scores. The authors interpret these data to mean that immunotherapy alters T-cell cytokine profiles in the long-term, and a decline of IL-4 following immunotherapy could modulate not only production of specific IgE antibodies but also inflammatory cellular events, leading to symptomatic relief in allergic rhinitis.

Adolescent↗

PubMed1996

SFA-1, a novel cellular gene induced by human T-cell leukemia virus type 1, is a member of the transmembrane 4 superfamily.

A novel cellular gene termed SFA-1 was isolated by differential hybridization of a cDNA library, using probes obtained from an adult T-cell leukemia cell line in comparison with probes obtained from normal CD4+ T cells and the MOLT-4 cell line. The mRNA of the SFA-1 gene is approximately 1.6 kb in size and encodes a protein of 253 amino acids, containing four putative transmembrane domains, a number of cysteine residues, and one potential N-glycosylation site in a major hydrophilic region between the third and fourth transmembrane domains. Expression of the SFA-1 gene was either absent or present at a low level in lymphoid cells but was up-regulated after transformation by human T-cell leukemia virus type 1 and transactivated by Tax. SFA-1 was broadly expressed in many human cell types and conserved in different species. Computer-aided comparison showed that SFA-1 had significant sequence homology and common structural features with members of the transmembrane 4 superfamily. SFA-1 antigen was detected as a 29-kDa membrane protein by immunoblotting, using anti-SFA-1 monoclonal antibody.

3T3 Cells↗

PubMed1996

Effect of ferrous ion on mildiomycin production by Streptoverticillium rimofaciens.

A specific regulatory effect of ferrous ion on a biosynthesis of mildiomycin by Streptoverticillium rimofaciens was investigated. The minimal concentration of ferrous ion necessary for the maximal production of mildiomycin was about 8 micrograms/ml. The physiological effects of ferrous ion on the mildiomycin production were examined in the media with and without the ferrous ion. Addition of ferrous ion to the culture medium increased both the mildiomycin production (10 times) and an assimilation of ammonium-nitrogen, activities of peptidase and protease.

Antifungal Agents↗

PubMed1996

Effect of phosphate ion on mildiomycin production by Streptoverticillium rimofaciens.

Effect of inorganic phosphate and ammonium nitrogen on mildiomycin production by Streptoverticillium rimofaciens was investigated in culture with and without addition of ferrous ion. In the presence of ferrous ion, the suitable supply of inorganic phosphate increased the intracellular ATP, but that was not observed without ferrous ion addition. The intracellular ATP remarkably affected ammonium nitrogen assimilation and mildiomycin production, and its concentration in the ferrous-sufficient culture was about 2 approximately 3 times higher than that in the ferrous-deficient culture. The low concentration of intracellular ATP in the ferrous-deficient culture resulted in the reduction of ammonium nitrogen assimilation and mildiomycin biosynthesis. This phosphate ion effect on the intracellular ATP concentration was demonstrated only when ferrous ion was added into the medium. These suggest that mildiomycin biosynthesis is regulated through the concentration of intracellular ATP related to the ammonium nitrogen assimilation.

Adenosine Triphosphate↗

PubMed1996

[A case of penile cancer treated with combination of chemotherapy, radiation and radical operation].

A 60-year-old [correction of 68] male was referred to our hospital because of a penile tumor with necrosis. Pathological examination of the penile tumor and superficial inguinal lymph nodes in biopsy revealed well differentiated squamous cell carcinoma (SCC) and the SCC tumor marker was elevated. TNM classification was T2, N2, M0 according to findings obtained by computed tomography (CT) and magnetic resonance imaging (MRI). We diagnosed the tumor inoperable radically and administered 10 mg peplomycin once a week for 10 weeks intravenously. The SCC marker level was not reduced and the tumor was not changed on MRI. Then, we performed combined pirarubicin treatment and radiotherapy. The patient received linac radiotherapy between 40 Gy/4 weeks/20 fractions. Pirarubicin, 10 mg/m2, was administered once a week for 4 weeks during irradiation intravenously. After the combined therapy, the SCC marked level was reduced to the normal range and the tumor was reduced. We performed radical operation. Pathological diagnosis revealed no viable tumor cells. The patient was alive with no evidence of disease a year later. This combined therapy is suggested to be useful.

Antibiotics, Antineoplastic↗

PubMed1995

Role of leucine 201 of thermostable D-amino acid aminotransferase from a thermophile, Bacillus sp. YM-1.

We studied the catalytic role of leucine 201 residue of the thermostable D-amino acid aminotransferase: the residue was shown crystallographically to be in the vicinity of the active site to interact with the bound pyridoxal phosphate. We replaced the leucine 201 by alanyl or tryptophanyl residues by means of site-directed mutagenesis. The L201A and L201W mutant enzymes showed anomalous kinetic behavior in the overall reaction. The reaction rates of the L201A and L201W mutant enzymes gradually decreased with an increase in the reaction time to become practically zero at a high concentration of substrates. The mutant enzymes were also inactivated in the half reaction with D-alanine, although more slowly than in the overall reaction. The absorption spectra of the mutant enzymes in the presence of D-alanine and alpha-ketoglutarate suggest that the enzyme molecules were mostly in the pyridoxamine form under the conditions employed. These phenomena were explained by assuming two (or more) enzyme species showing kinetically different catalysis for pyridoxamine form of the mutant enzymes, and the rate of conversion from one of these pyridoxamine forms to the pyridoxal form should be very low. The leucine 201 residue probably regulates the function of cofactor during the reaction of D-amino acid aminotransferase.

Alanine↗

PubMed1995

Clinical, microbiological and host defense parameters associated with a case of localized prepubertal periodontitis.

A 4-year-old Japanese boy was referred to Osaka University Dental Hospital because of severe mobility and pain of the right lower primary canine. The canine had severe bone loss and a pocket depth exceeding 5-6 mm. The left lower canine showed slight mobility and moderate alveolar bone loss. The other primary teeth showed no pathogenic findings. The subgingival microflora from the right lower canine was dominated by gram-negative rods, especially capnocytophaga and fusobacterium, while actinomyces sp. were the most common gram-positive bacteria. While neutrophil functions of the patient were within the normal ranges of healthy subjects, some lymphocyte functions such as IL-2 production and IgG and IgM syntheses were lower in the patient. 7 months after the extraction of the right lower primary canine, the patient complained of pain around the right lower primary lateral incisor. In 3-4 weeks, the alveolar bone was lost rapidly and mobility of the lower anterior teeth increased significantly. The primary lateral incisor was extracted and the other primary teeth were treated by sealing and systemic and local administration of antibiotics. After treatment, the lower anterior teeth became less mobile and the gram-positive cocci predominated.

Actinomyces↗

PubMed1995

[Quinolone-resistant mutations in Neisseria gonorrhoeae].

For 10 strains of Neisseria gonorrhoeae exhibiting decreased susceptibility to new quinolones (MIC, > or = 0.1 microgram/ml) isolated and preserved from patients with gonococcal urethritis during the period from February 1991 through January 1992. We investigated the mechanisms for development of resistance to new quinolones. After selecting 3 PCG-sensitive and new quinolone-resistant strains from among these strains, we first carried out transformation experiments of N. gonorrhoeae using a plasmid carrying the E. coli gyrA gene. We then determined the base sequence on the N. gonorrhoeae gyrA gene by PCR method. Of the 3 strains in which transformation experiments were carried out, 2 strains yielded transformants, one of which was 8 times more sensitive to norfloxacin (NFLX) than the original strain, and it was assumed that this strain has a mutation in the gyrA gene. In our study of the base sequence on the N. gonorrhoeae gyrA gene using the PCR method, both strains had the mutation of Ser 83 (TCC)-->Phe (TTC), and in addition to this mutation of Ser-->Phe, one other strain had the mutation of Asp-87 (GAC)-->Gly (GGC). This type of mutation of quinolone-resistant N. gonorrhoeae on the gyrA gene has high homology with the mutations reported for Escherichia coli and other strains and there appears to be a close correlation between the increasing frequency of use of the new quinolones in this country and the spread of such resistant strains of N. gonorrhoeae.

Drug Resistance, Microbial↗

PubMed1995

Immunocytochemical localization of platelet-type arachidonate 12-lipoxygenase in mouse blood cells.

Arachidonate 12-lipoxygenase is an enzyme that oxygenates the 12 position of arachidonic acid to produce its 12-hydroperoxy derivative. We were interested in the tissue distribution and subcellular localization of the platelet-type 12-lipoxygenase, which is distinguished from the leukocyte type by several criteria. Antiserum was raised in rabbits against purified recombinant arachidonate 12-lipoxygenase of human platelets. When mouse bone marrow cells and lung were immunostained and observed by light and electron microscopy, the positively stained cells were platelets, megakaryocytes, and eosinophils. 12-Lipoxygenase was localized in the cytoplasm of platelets but was hardly detectable in the plasma membrane and intracellular organelles. The enzyme was found in the cytoplasm of immature megakaryocytes with kidney-shaped nuclei and a few profiles of demarcation membranes, as well as in the mature form with well-developed demarcation membranes. These results indicated the expression of 12-lipoxygenase at an early stage in the course of megakaryocytopoiesis.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1995

Influence of daily subcutaneous administration of reserpine for 4 weeks or 9 weeks before mating on testis, sperm and male fertility in rats.

To determine the optimum period of drug treatment and assessment parameters to evaluate male fertility in rats, different methods of examination and periods of treatment before mating were investigated in Sprague-Dawley (Crj:CD) male rats treated with a testicular oxicity-inducing agent, reserpine. The rats were given reserpine subcutaneously at daily doses of 0.05, 0.1 and 0.2 mg/kg for 4 and 9 weeks (4-week test and 9-week test). Reproductive performance was tested and after mating, the testes, epididymides, prostate and pituitary weights were measured. Sperm analysis and histopathological examinations of the genital organs were also performed in the 4-week test case. After 4 weeks, prostate weight was decreased and the implantation rate showed a tendency for decrease. Histopathological examination of the testes revealed changes such as retention of step 19 spermatids in the seminiferous tubules of stages IX to XII, although sperm analysis showed no abnormal findings. In the 9-week test, testes and prostate weights were decreased along with the implantation rate was decreased. In conclusion, of the approaches used to evaluate the effects of reserpine on male fertility, histopathological examination and measurement of genital organ weights proved more sensitive than reproductive performance testing and sperm analysis. Regarding the optimum treatment period, 4 weeks was found to be sufficient for detection of histopathological and genital organ weight changes.

Animals↗

PubMed1995

[Method for daily administration of low-dose CDDP and 5-FU combined with radiotherapy for oral squamous cell carcinoma].

Daily administration of low-dose CDDP and 5-FU combined with radiotherapy was performed in three cases of oral squamous cell carcinoma in aged patients whose general condition was poor. One course of chemotherapy consisted of daily administration of CDDP (10 mg iv, days 1-5) and 5-FU (250-500 mg iv, days 1-5) with radiotherapy (total dose of 60-64 Gy). Two or three courses were performed at some interval. There were no severe side-effects except for mucositis. Tumors disappeared in all three cases, and a complete response was achieved in two cases. The method appeared to be safe and useful for oral squamous cell carcinoma patients of advanced age and poor general condition.

Aged↗

PubMed1994

Site-directed mutagenesis studies on the iron-binding domain and the determinant for the substrate oxygenation site of porcine leukocyte arachidonate 12-lipoxygenase.

cDNA for arachidonate 12-lipoxygenase of porcine leukocytes was expressed in Escherichia coli. The recombinant 12-lipoxygenase was purified by immunoaffinity chromatography to near homogeneity with a specific activity of about 1.5 mumol/min per mg protein. Each of eight histidine residues, which were well-conserved among various mammalian lipoxygenases and presumed as ligands for non-heme iron, was substituted with leucine by site-directed mutagenesis. Each mutant enzyme was immunoaffinity-purified to near homogeneity. Mutations of His-361, -366 and -541 caused a total loss of enzyme activity, and the iron content was much lower (0.10, 0.06 and 0.06 g atom/mol protein) than that of the wild-type enzyme (0.53). Mutations of His-128 and -356 gave 159% and 162% specific activity of the wild-type enzyme, and the iron contents were 0.55 and 0.52 g atom/mol protein. Substitution of His-426 decreased the activity to 5%, but the iron content was 0.4 g atom/mol protein. The expression level of mutants at His-384 and -393 was too low to precisely determine the iron content. Taken together, His-361, -366 and -541 may play important roles for iron-binding in catalytically active 12-lipoxygenase. Since a high homology of amino acid sequence was known between porcine leukocyte 12-lipoxygenase and mammalian 15-lipoxygenases, we attempted to convert the 12-lipoxygenase to a 15-lipoxygenase. A double mutation of Val-418 and -419 to Ile and Met increased the ratio of 15- and 12-lipoxygenase activities from 0.1 to 5.7.

Amino Acid Sequence↗

PubMed1994

Interleukin-4 in chronic myelomonocytic leukemia. Growth suppression of hematopoietic precursors in the chronic phase and stimulation in the acute phase.

We examined the effects of interleukin-4 (IL-4) on the growth of hematopoietic precursors from a patient with chronic myelomonocytic leukemia (CMMoL). In the chronic phase of the disease, IL-4 inhibited spontaneous colony formation by CMMoL cells in semi-solid culture. However, in the acute phase, IL-4 promoted colony formation. These effects of IL-4 were abolished completely by the addition of anti-IL-4 neutralizing antibodies. The spontaneous colony formation by CMMoL cells in both the chronic and acute phases was inhibited by the addition of anti-IL-6 antibodies. On the other hand, neither anti-IL-6, anti-granulocyte macrophage colony-stimulating factor (GM-CSF), anti-IL-1 beta nor anti-tumor necrosis factor alpha (TNF alpha) antibodies inhibited IL-4-induced colony formation by CMMoL cells in the acute phase. IL-4 suppressed the production of IL-6 by CMMoL cells in both the chronic and acute phases. These results suggest that in the present patient, IL-4 suppressed the IL-6-mediated autocrine growth of CMMoL cells in both the chronic and acute phases, but directly stimulated their growth in the acute phase.

Antibodies↗

PubMed1993

Regulation of expression of the ligand for CD40 on T helper lymphocytes.

Activated Th cells deliver contact-dependent signals to resting B lymphocytes that initiate and drive B cell proliferation. Recently, a ligand for the B lymphocyte membrane protein, CD40, has been identified that delivers contact-dependent Th cell signals to B cells. A dimeric soluble form of CD40 was produced and used to further characterize the regulation of expression of the CD40 ligand. Expression of the CD40 ligand was rapidly induced after Th lymphocyte activation, and its stability depended upon whether Th cells were activated with soluble or plastic-bound stimuli. Th cells activated with soluble stimuli rapidly turned over cell-surface CD40 ligand whereas Th cells activated with plastic-bound stimuli exhibited more stable CD40 ligand expression for up to 48 h. Removal of activated Th cells from the plastic-bound stimulus resulted in a rapid turnover of CD40 ligand, suggesting that continuous stimulation could maintain CD40 ligand expression. Ligation by soluble CD40 could also stabilize expression of CD40 ligand on the Th cell surface. Both CD40 ligand and IL-2 were transiently synthesized from 1 to 12 h after Th cell activation and had similar kinetics of synthesis. In Con A-activated Th cells newly synthesized CD40 ligand exhibited an initial high turnover (1.5 h t1/2) and after 5 h of Th cell activation became more stable (10-h t1/2). In Th cells activated with plastic-bound anti-CD3, CD40 ligand exhibited a similar biphasic turnover except that the rapid turnover phase began significantly later. This delay could allow more time for newly synthesized CD40 ligand to assemble or associate with other molecules and thus become stabilized on the cell surface. Newly synthesized CD40 ligand in Con A-activated Th cells appeared to not be efficient in delivering Th cell-dependent contact signals to resting B cells, implying the need for assembly or accessory proteins. Regulation of CD40 ligand expression was consistent with all the characteristics of Th cell-delivered contact signals to B cells and may contribute to the high degree of specificity in B cell responses.

Animals↗

PubMed1992

Molecular structure and function of the porcine arachidonate 12-lipoxygenase gene.

The gene encoding arachidonate 12-lipoxygenase was cloned from a porcine EMBL3 genomic library using a cDNA probe of the enzyme, and its nucleotide sequence was determined. The gene consists of 14 exons with 13 introns, and spans approximately 8 kilobases. Analysis of splice junctions indicated that all of the splice donor and acceptor sites conformed to the GT/AG rule. An approximately 1-kilobase region upstream of the coding sequence contains nine GC-boxes for potential Sp1-binding sites at positions -77, -135, -145, -165, -214, -636, -643, -684, and -813. There are two sets of AP-2 binding sequence at positions -234 and -402. Neither typical TATA box nor CCAAT box is found in this region. The transcriptional start site was determined by primer extension analysis, and was tentatively identified as a cytidine residue located 19 bases upstream from initiation codon. Southern blot analysis revealed the presence of one copy of 12-lipoxygenase gene per haploid genome. We found striking similarities in genomic organization as well as the promoter sequences between the porcine 12-lipoxygenase and the rabbit 15-lipoxygenase genes, suggesting that these genes are evolutionarily related.

Amino Acid Sequence↗