Biomedical subjects

K Iwata

Publications and source records attributed to K Iwata.

At least 127 records · Page 7Linked to original sources

PubMed1997

Immunolocalization of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human chondrosarcomas.

We have immunohistochemically examined the localization of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in human chondrosarcomas (CHS) (23 cases) and benign chondroid lesions (BCL) (16 cases of osteochondromas and 11 cases of enchondromas). In CHS, all the MMPs and TIMPs examined were positive. Among them, MMP-1 was immunolocalized in more than 90% of both CHS and BCL, but positive score of MMP-1 was significantly higher in CHS than that in BCL (p < 0.01). Compared with BCL, CHS expressed MMP-3 at a low level, and more often positive in MMP-9. It is possible that chondrosarcoma might have a tendency to lose the ability to secrete MMP-3, which is a metalloproteinase that can degrade cartilage proteoglycans and is related to normal cartilage turnover. MMP-2, TIMP-1 and TIMP-2 were immunolocalized in more than 70% of the cases of both BCL and CHS, but the positive scores of these were not statistically different between the two groups. Interestingly, in several cases of CHS, both MMP-1 and MMP-9 immunostains were observed preferentially within the cells at the marginal areas of cartilaginous lobules. These findings suggest that increased expression of MMP-1 and MMP-9 and decrease in MMP-3 expression are associated with the malignant phenotype of the cartilaginour tumors.

Adult↗

PubMed1997

Serial quantitation of serum core protein and viral RNA of hepatitis C virus after interferon therapy: increase in viral loads in biochemical responders.

OBJECTIVES: Interferon (IFN) therapy is often ineffective in eradicating hepatitis C virus (HCV). Some patients show normal serum ALT levels for a long time after IFN therapy despite the presence of HCV. These patients are considered not virological responders but biochemical responders. We investigated the changes in the amount of HCV after IFN therapy in biochemical responders. METHODS: Nine biochemical responders and 11 nonresponders were studied. Serum HCV amount was measured by fluorescence enzyme immunoassay for HCV core (pg/ml) and Amplicor HCV Monitor test for HCV RNA (logarithms of copy numbers per milliliter). RESULTS: In biochemical responders, core protein and HCV RNA were increased significantly at 1 month after IFN therapy (291 +/- 191 pg/ml and 5.4 +/- 0.9, respectively; p < 0.05 for both) and at 1 yr (324 +/- 189 pg/ml and 5.6 +/- 0.7, respectively; p < 0.01 for both) compared with pretreatment values (122 +/- 114 pg/ml and 4.8 +/- 0.9, respectively). The change ratios of core protein at 1 month and 6 months after therapy to the pretreatment values were significantly higher in biochemical responders (3.2 +/- 2.4 and 2.9 +/- 2.3, respectively) than in nonresponders (0.9 +/- 0.7 and 1.1 +/- 0.8, respectively) (p < 0.05 for both). Similarly, the change ratios of HCV RNA at 1 month and 1 yr after IFN therapy were significantly higher in biochemical responders (9.9 +/- 14.6 and 12.8 +/- 15.1) than in nonresponders (0.6 +/- 0.5 and 1.2 +/- 1.2) (p < 0.05 for both). CONCLUSIONS: HCV amount increased significantly after IFN therapy in biochemical responders, whereas it did not change notably in nonresponders.

Alanine Transaminase↗

PubMed1997

[Coronary artery spasm during anesthetic induction in a patient with bronchial asthma].

A 68-year-old man was scheduled for subtotal gastrectomy. He had bronchial asthma, but had no history of ischemic heart disease and showed normal ECG. He stopped taking antiasthmatic drugs after the admission. His operation had been postponed for 10 days for an attack of bronchial asthma. The asthmatic attack was suppressed by infusing aminophilline. Before the operation, general anesthesia combined with epidural anesthesia (mepivacaine; 60 mg) was induced. At the time of the insertion of a stomach tube, bradycardia (48 bpm) and hypotension (48/30 mmHg) with an elevation of ST-segment in ECG were observed. We administrated 10 mg of isosorbide dinitrate followed by continuous intravenous injection (0.5 mg.kg-1.min-1) of dopamine (6 mg.kg-1.min-1). After 20 minutes, increases of both blood pressure (82/49 mmHg) and heart rate (89 bpm) were achieved and ST-segment in ECG was reversed. The operation was postponed again. Although the patient had refused to take coronary angiogram, the episode was explained by coronary artery spasm. Pathogenesis of the spasm was likely to be 1) elevation of endogenous cathecolamine due to asthma, 2) inhibition of cardiac sympathetic system by epidural anesthesia and 3) stimulation of vagal system by the insertion of a stomach tube.

Aged↗

PubMed1997

[Cyst of the tunica albuginea associated with intraabdominal testes: a case report].

A case of cyst of the tunica albuginea associated with intraabdominal testes is reported. A 35-year-old man was referred for further examination of azoospermia. Bilateral testes were nonpalpable in the scrotum and inguinal region. Ultrasonography and MR imaging demonstrated a 9 x 8 cm cystic lesion in the median suprapubic area. An open operation showed the cystic lesion to extend to the right spermatic cord and vas deferens. Left intraabdominal testis was also identified. Right orchiectomy and left orchiopexy were performed. Histopathological diagnosis was a cyst of the tunica albuginea. Atrophic seminiferous tubules were recognized at the junction of the cyst and the spermatic cord.

Adult↗

PubMed1996

Morphological and electrophysiological properties of ACCx nociceptive neurons in rats.

A total of 33 neurons with cutaneous receptive fields were recorded from the anterior cingulate cortex (ACCx) and successfully injected with neurobiotin. All neurons were in area 24 of the ACCx. Neurons from the ACCx had large receptive fields (RFs), usually bilateral, and some had RFs covering the whole body surface. Most of the neurons were in the deep laminae and had a pyramidal soma with thick apical dendrites and many spines. Thirteen of 33 neurons were classified as pyramidal nociceptive specific (NS) neurons and 12 as noxious-tap neurons, 3 neurons received inhibitory input and were in lamina V. Two non-pyramidal noxious-tap neurons were located in lamina V and 1 pyramidal noxious-tap neuron was located in lamina VI, and 2 pyramidal NS neurons were in lamina III. Axon collaterals of NS neurons were mainly distributed around the soma, whereas those of noxious-tap neurons were also distributed far from the soma. A large number of varicosities were observed on the axon collaterals of both NS and noxious-tap neurons. Our results suggest that NS neurons in the ACCx send information locally to the vicinity of the soma, while noxious-tap neurons send information to a wider area of the ACCx.

Animals↗

PubMed1996

Differential regulation of vitamin D receptors in clonal populations of a chronic myelogenous leukemia cell line.

RWLeu4 is a chronic myelogenous leukemia cell line that is sensitive to the antiproliferative and differentiation-inducing actions of 1alpha,25(OH)2-vitamin D3 (VD3). The JMRD3 cell line is a VD3-resistant variant of RWLeu4 that was selected by continuous passage of RWLeu4 in the presence of VD3. The isolation of a spontaneous VD3-resistant variant suggests that phenotypically different cells exist within the RWLeu4 cell population. Therefore, single-cell clones of RWLeu4 cells were isolated and characterized. Four clonal cell populations that fall into three groups differing in response to the antiproliferative and differentiation-inducing actions of VD3 were examined. Surprisingly, the extent of response of the clones to VD3 does not show a correlation with the basal level of the vitamin D receptor (VDR). RWLeu4-3 and RWLeu4-4 are the clones most sensitive to the antiproliferative actions of VD3 (ED50 approximately equal to 1 nM); however, RWLeu4-3 expresses basal levels of VDRs similar to those found in the parental cells and the RWLeu4-2 clone, while in RWLeu4-4, VD3 binding and VDR protein are below the limits of detection. Furthermore, RWLeu4-10 expresses the highest basal level of VDR protein but is relatively resistant to the antiproliferative actions of VD3 (ED50 > or = 30 nM). Like JMRD3, RWLeu4-10 is still capable of differentiating in response to VD3, as judged by the induction of biochemical processes and cell-surface antigen expression. Although VD3 treatment increases VDR protein levels and DNA-binding activity in all clones, altered DNA-protein complexes are detected in RWLeu4-4. Our results suggest that sensitivity to the antiproliferative and differentiation-inducing actions of VD3 is not dependent solely upon the level of VDR expressed, but may also require posttranslational modification of the VDR or complex interactions with other nuclear transcription factors.

Base Sequence↗

PubMed1996

Characterization of c-myc-transformed rat fibroblasts resistant to apoptosis induced ny growth factor deprivation.

Under appropriate conditions (e.g., growth factor withdrawal), the deregulated expression of c-myc in rodent fibroblasts leads to substantial cell death due to apoptosis. To better understand this process, we selected for c-myc-transformed Rat1A fibroblasts that were resistant to growth factor deprivation-induced cell death. One clonal isolate exhibited prolonged survival in serum-free medium and displayed reduced levels of apoptosis-related DNA fragmentation. These cells were also resistant to induction of apoptosis by the protein kinase inhibitor staurosporine. They retained a transformed cell phenotype and expressed the proviral human c-myc allele in an unaltered fashion, strongly indicating that the mutation of a cellular gene other than c-myc accounts for the apoptosis-resistant phenotype. The results of somatic cell hybrid analysis of this cell line are consistent with a recessive mutation. Our findings suggest a novel mechanism for abrogation of apoptosis in neoplastic cells and provide a model system for the study of its role in tumorigenesis and resistance to antineoplastic therapy.

Alkaloids↗

PubMed1996

Interaction between tissue inhibitor of metalloproteinases-2 and progelatinase A: immunoreactivity analyses.

By immunoreactivity analysis using monoclonal antibodies, we showed that the C-terminal domain [R415-631; R is residue] of progelatinase A [pro-matrix metalloproteinase-2 (proMMP-2); EC 3.4.24.24] affected the immunoreactivity of a one-step sandwich enzyme immunoassay (sandwich EIA) for tissue inhibitor of metalloproteinases-2 (TIMP-2) in exactly the same way as does proMMP-2 [Fujimoto, Zhang, Iwata, Shinya, Okada and Hayakawa (1993) Clin. Chim. Acta 220, 31-45], confirming that the C-terminal domain ("tail" portion of TIMP-2 participates in the binding with the C-terminal domain of proMMP-2. We also demonstrated that not only the C-terminal domain but also the N-terminal domain (R1-417) of proMMP-2 bound to TIMP-2 in a 1:1 molar ratio. The binding of each individual domain to TIMP-2, however, was weak enough that either domain could be fully replaced by proMMP-2 through the same binding sites as does proMMP-2, and also that the high-order structure of proMMP-2 allows a more stable binding to TIMP-2. We further confirmed that TIMP-2 complexed with the N-terminal domain of pro-MMP-2 had fully inhibitory activity against the collagenolytic activity of MMP-1. We also demonstrated that either the interstitial collagenase-TIMP-2 complex or the gelatinase B(MMP-9)-TIMP-2 complex was able to form a ternary complex with proMMP-2 in a 1:1 molar ratio, clearly indicating that there are two distinct binding sites, one specific for proMMP-2 complex, but the binding seemed to be less stable than the binding with TIMP-2 alone. Even in the presence of a 10-fold molar excess of the N-terminal domain, ternary complex formation was not observed between the N-terminal domain and the MMP-9--TIMP-2 complex. These clear differences might be ascribed to some significant conformational change(s) evoked in the TIMP-2 molecule, or hindrance of a part of the N-terminal domain binding site of TIMP-2 by complex formation with MMP-9.

Animals↗

PubMed1996

A one-step sandwich enzyme immunoassay for human matrix metalloproteinase 8 (neutrophil collagenase) using monoclonal antibodies.

A one-step sandwich enzyme immunoassay (EIA) system for human matrix metalloproteinase 8 (MMP-8, neutrophil collagenase, EC 3.4.24.7) has been established with a pair of monoclonal antibodies prepared against the zymogen of MMP-8 purified from human neutrophils. MMP-8 in samples simultaneously reacted with both solid-phase and peroxidase-labeled antibodies. Sensitivity of this EIA system was 0.34 micrograms/l (5.7 pg/assay) and linearity was obtained between 0.5 and 500 micrograms/l (8.3-8300 pg/assay). The EIA system recognized both precursor and active forms of MMP-8 but not MMP-8 complexed with tissue inhibitors of metalloproteinases. There was no difference in the MMP-8 levels between the plasma samples from patients with rheumatoid arthritis or osteoarthritis and those from healthy subjects (median 6.2 micrograms/l, range 1.5-28 micrograms/l). However, the level in synovial fluids from patients with rheumatoid arthritis (median 345 micrograms/l, range 84-2860 micrograms/l) was shown to be higher than that from osteoarthritic patients. MMP-8 levels in human whole saliva from patients with periodontal diseases (median 282 micrograms/l, range 0-1420 micrograms/l) were also significantly higher than those from clinically healthy subjects (median 25 micrograms/l, range 0-100 micrograms/l). Immunoreactivity analyses showed that MMP-8 species in normal human plasma exists as a precursor but not as a complex form with tissue inhibitor of metalloproteinases (TIMP)-1 or TIMP-2.

Animals↗

PubMed1996

A one-step sandwich enzyme immunoassay for human matrix metalloproteinase 7 (matrilysin) using monoclonal antibodies.

A one-step sandwich enzyme immunoassay (EIA) system for human matrix metalloproteinase 7 (MMP-7, matrilysin, EC 3.4.24.23) was established with a pair of monoclonal antibodies prepared against the zymogen of MMP-7 (proMMP-7) purified from CaR-1 human rectal carcinoma cells and against an oligopeptide corresponding to the C-terminal domain of human proMMP-7. ProMMP-7 in samples was allowed to simultaneously react with both solid-phase and peroxidase-labeled antibodies. Sensitivity of the EIA system in the presence of EDTA was 0.05 microgram/l (1.5 pg/assay) and linearity was obtained between 0.156-10 micrograms/l (4.68-300 pg/assay). ProMMP-7 levels in human sera from healthy subjects were shown to be in the range of 10.7 +/- 18.8 micrograms/l. Gel filtration analyses indicated that proMMP-7 makes polymers after treatment with EDTA and suggested that proMMP-7 exists as polymers in normal human sera.

Amino Acid Sequence↗

PubMed1996

Serial analysis of hepatitis B virus core nucleotide sequence of patients with acute exacerbation during chronic infection.

Recent studies suggest that hepatitis B virus (HBV) core region could be an immunological target and that amino acid (aa) substitutions are mostly restricted to a small segment located in the middle of the core region. We sequenced the middle portion of HBV core gene during the course of acute exacerbation of chronic hepatitis B, and compared aa variations between the region including ideal HLA-A2 binding motifs and the nonbinding region. Five HBeAg+ chronic hepatitis patients with subtype adr (three with HLA-A2 and two without HLA-A2) were selected and using polymerase chain reaction (PCR) and cloning system, the central part of core region (nt 2063 to 2365, 303 bp) was sequenced in sera from each patient at three time points; before, at the peak of, and after exacerbation of hepatitis. The second set of sera showed higher aa substitution rates in five and in three out of five patients compared with those of the first and third sera, respectively. No significant difference was found in the aa substitution rates for the region with ideal HLA-A2 binding motifs between patients with and without HLA-A2. In asymptomatic HBV carriers with persistently normal aminotransferase values, alterations of the aa sequence were not observed within the same time frame. The results suggest that aa substitutions often occur at some particular positions in the middle of HBV core region during acute exacerbation of the disease under possible host immune pressures. Furthermore, unidentified epitopes appear to exist in the central part of HBV core region and HLA-unrestricted lymphocytes may play a role in the immune response of chronic HBV carriers.

Adult↗

PubMed1996

High seroprevalence of anti-HTLV-I antibody in rheumatoid arthritis.

OBJECTIVE: To investigate the association between human T lymphotropic virus type I (HTLV-I) infection and rheumatoid arthritis (RA) in Nagasaki, an area highly endemic for HTLV-I infection. METHODS: Sera from 113 female patients with RA and 19,796 female blood donors were screened for anti-HTLV-I antibodies with a gelatin particle agglutination kit and confirmed using an immunoblotting kits. RESULTS: The age-adjusted summary odds ratio of HTLV-I infection among RA patients, as compared with blood donors, was 2.8 (95% confidence interval [95% CI] 1.8-4.6). The etiologic fraction, i.e., the proportion of RA in the study population that is attributable to HTLV-I infection, was estimated to be 13.2% (95% CI 5.1-21.2). There was no significant difference in the clinical and laboratory findings between HTLV-I- infected and HTLV-I-uninfected RA patients. CONCLUSION: These epidemiologic findings support the idea that HTLV-I infection is a risk factor for RA, and suggest that approximately 13 % of the cases of RA in females living in Nagasaki are associated with HTLV-I infection.

Adult↗

PubMed1996

Hypervariable region sequence in cryoglobulin-associated hepatitis C virus in sera of patients with chronic hepatitis C: relationship to antibody response against hypervariable region genome.

Essential mixed cryoglobulinemia is frequently associated with hepatitis C virus (HCV) infection, with the formation of HCV antigen/antibody complexes. The hypervariable region (HVR) of the HCV E2/NS1 region is thought to include epitopes for neutralizing antibodies, but it remains uncertain whether cryoglobulins (CGs) contain such antibody-bound HCV. Thus, we studied HVR clones isolated from cryoprecipitate and supernatant in the sera of four chronic hepatitis C patients with cryoglobulinemia, and expressed as fusion proteins with glutathione S-transferase (GST). Patients' sera were tested for antibody binding to the proteins. The rate of anti-HVR antibody-positive clones was significantly higher in cryoprecipitate (89% +/- 13%, P < .05) than in supernatant (41% +/- 25%). Both HCV RNA and anti-HVR antibody were more concentrated in cryoprecipitates compared with those of serum and supernatant in two patients tested. Anti-HVR antibody-positive clones in cryoprecipitate showed common amino acid (aa) sequences in each of the four patients. Similarly, all the antibody-positive clones in supernatant showed the same aa sequences for three of the four patients. When aa sequences were compared with those of reported isolates with genotype 1b, the mean percentage of aa difference was greater in the clones from supernatant and in anti-HVR antibody-negative clones than in the clones from cryoprecipitate and in the antibody-positive clones, respectively. These findings indicate that serum CG contains anti-HVR antibody-bound HCV in patients with chronic hepatitis C. Anti-HVR antibody-free individual clones, which were more frequently noted in supernatant, showed closely related sequences, but which were of a heterogeneous quasispecies nature.

Adult↗

PubMed1996

Epitope mapping of capsid proteins VP2 and VP3 of infectious bursal disease virus.

Twenty hybridoma cell lines producing monoclonal antibodies (MAbs) against serotype 1 infectious bursal disease virus (IBDV) of GBF-1 and the attenuated GBF-1E strains were produced. The MAbs recognized major structural proteins VP2 and VP3. MAb recognition sites were mapped using recombinant Escherichia coli clones which expressed N-terminal and (or) C-terminal truncated virus antigens, and competitive-binding assays. At least 3 conformation-dependent serotype 1 specific virus neutralizing antigenic sites and a linear antigenic site were defined on VP2 and VP3, respectively. Two of the conformational virus neutralizing antigenic sites were localized in the central area of VP2 consisting of 156 amino acid residues, and the linear epitope was localized in C-terminal 105 amino acid residues of VP3. Another conformational virus neutralizing antigenic site recognized with the virus neutralizing MAb GK-5 was not defined because GK-5 did not react with virus antigen expressed in recombinant E. coli. The conformational antigenic site was supposed to be composed of tertiary or quaternary protein structure, which may not be constructed in recombinant E. coli.

Animals↗

PubMed1996

Surfactant therapy for respiratory failure due to near-drowning.

We report a nearly drowned 3-year-old boy who was treated successfully with exogenous bovine surfactant. Exogenous surfactant should be administered to patients with refractory respiratory failure based on the pulmonary pathophysiology in near-drowning.

Biological Products↗

PubMed1996

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in colonic adenomas-adenocarcinomas.

UNLABELLED: Colonic adenocarcinomas evolve through a multistep process from tubular adenomas to invasive adenocarcinomas. Matrix metalloproteinases (MMPs) have been implicated in proteolysis of basement membrane for initiation of metastatic cascade. METHODS: By immunocytochemical staining, hyperplastic polyps, tubular adenomas, tubovillous adenomas, villous adenomas to adenocarcinomas were systematically examined for the presence of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) and tissue inhibitor of MMP (TIMP)-1 and TIMP-2, respectively. RESULTS: MMP-2 and MMP-9, and TIMP-1 and TIMP-2 were immunolocalized in scattered stromal cells, whereas epithelial cells of normal mucosa and hyperplastic polyps were weakly stained. From tubular adenomas to villous adenomas, immunolocalization of gelatinases and TIMPs showed increasing gradually, and in situ carcinomas showed a definite positive, immunolocalization of gelatinases and TIMPs. CONCLUSION: Increasing immunolocalization of gelatinases and TIMPs from tubular adenomas to adenocarcinomas coincides with a multistep process of colonic tumorigenesis.

Adenocarcinoma↗

PubMed1996

Utilization of DNA as functional materials: preparation of filters containing DNA insolubilized with alginic acid gel.

Thin films composed of DNA and alginic acid were prepared by casting their mixed solution on glass plate followed by coagulation with aqueous solution of calcium chloride. DNA could be conveniently insolubilized by this method. DNA in the films adsorbed intercalating materials, such as ethidium bromide. This phenomenon was successfully applied to the preparation of filters for the selective removal or accumulation of harmful intercalating pollutants.

Adsorption↗

PubMed1996

Vasoinhibitory effect of leminoprazole, a H+,K(+)-ATPase inhibitor, on rat aortic rings.

1. In isolated rat aortic rings, leminoprazole (2-[2-N-methyl-N-(2-methylpropyl)amino]benzylsulfinyl benzimidazole) (10(-6) - 10(-4) M) inhibited contractile responses to phenylephrine (PE), KCl and Ca2+ in KCl-depolarized tissues in a Ca2+ free medium. Leminoprazole also relaxed the aorta contracted by PE and KCl. 2. The relaxing effect of leminoprazole was markedly inhibited by nifedipine and verapamil (inhibitors of voltage operated Ca2+ channels). Relaxation induced by verapamil, but not by nifedipine, was inhibited by pre-treatment by leminoprazole. 3. The relaxing effect of leminoprazole was also inhibited by NG-monomethyl-L-arginine (a nitric oxide synthase inhibitor), methylene blue (a guanylate cyclase inhibitor) or endothelium removal but not by indomethacin (a cyclooxygenase inhibitor), glyburide (a KATP channel inhibitor) or iberiotoxin (a KCa channel inhibitor). 4. Zaprinast (a cGMP-phosphodiesterase inhibitor) also inhibited the relaxing action of leminoprazole. In addition, relaxation induced by nitroglycerin was potentiated by leminoprazole. 5. Further, in the presence of methylene blue, residual relaxation induced by leminoprazole was still potentiated by verapamil. 6. These results suggest that the vasoinhibitory effect of leminoprazole in rat aortic rings is due to the increased level of cGMP through inhibition of cGMP-phosphodiesterase and also due to inhibition of voltage operated Ca2+ channels.

Animals↗