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Biomedical subjects

K Kawata

Publications and source records attributed to K Kawata.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Evaluation of an HIV screening assay kit for the combined detection of anti-HIV-1/2 antibodies and HIV p24 antigen].

We have evaluated a new HIV screening assay kit (Genscreen HIV Ag-Ab) for the HIV antigen-antibody combined test by comparing with two HIV antigen-antibody combined assay kits (VIDAS HIV DUO, Enzygnost HIV integral). Genscreen HIV Ag-Ab is a microwell plate enzyme immunoassay for the detection of HIV infection, based on the detection of anti-HIV-1/2 antibodies and HIV p24 antigen in human serum or plasma. In this study, 90 samples of HIV-1 antibody positive sera and 670 samples of HIV negative sera were examined. The sensitivity was 100% and the specificity was 99.7%. All of HIV-1 group M sera (subtypes A to G and B/D), HIV-1 group O sera and HIV-2 sera in worldwide HIV performance panel-302 were positive with Genscreen HIV Ag-Ab. Ten commercially available HIV-1 seroconversion panels were tested to evaluate sensitivity of three HIV antigen-antibody combined assay kits. Genscreen HIV Ag-Ab detected infection at the same bleeds as VIDAS HIV DUO in 8 of 10 seroconversion panels and 1 to 2 bleeds earlier than Enzygnost HIV integral in 5 of 10 seroconversion panels. However, VIDAS HIV DUO indicated false negative on 5th bleed in panel BB (PRA952). The result of the specimen was positive on 3rd bleed, equivocal on 4th bleed, negative on 5th bleed and again positive on 6th bleed. All of these specimens were positive by Genscreen HIV Ag-Ab. Therefore, Genscreen HIV Ag-Ab that shorten the window period is a useful and reliable for HIV screening test, especially in case of primary infection.

AIDS Serodiagnosis↗
PubMed2001

[The examinations associating with hepatitis C virus and medical reimbursement].

The number of persons infected with hepatitis C virus(HCV) is estimated to be about one to two million in Japan. Recently researchers have shown a growing interest in HCV, since the virus infection may cause liver cirrhosis and hepatocellular carcinoma. The examinations for HCV can be divided into host factor and virus factor detection methods. Classification and cost of HCV tests are shown. Antibody tests as host factor detection are used to screen for infection, for auxiliary diagnosis of viremia and for choosing treatment. Virus factor tests, such as the measurement of the viral load can be used for choosing treatment and determining the response to therapy. We describe that usage of laboratory tests for HCV and discuss medical insurance coverage.

Hepatitis C↗
PubMed2000

New gamma-fluoromethotrexates modified in the pteridine ring: synthesis and in vitro immunosuppressive activity.

Our continuing program to develop new antifolate drugs useful against rheumatoid arthritis led us to modify the pteridine ring of gamma-fluoromethotrexate. Pyrrolopyrimidine derivatives 1e and 1t were found to exhibit potent suppressive effects on the responses of both T and B cells to mitogens, although tetrahydropyridopyrimidine derivatives 2e and 2t and quinazoline derivatives 3e, 3t and 4e showed very weak suppressive activities. Thus, conversion of the pteridine ring of gamma-fluoromethotrexate to a pyrrolopyrimidine ring led to a new potential antirheumatic compound.

Antirheumatic Agents↗
PubMed2000

Seroprevalence of antibodies to Chlamydia spp. in human immunodeficiency virus-infected subjects in Japan.

To evaluate the seropositivity of Chlamydia spp. in human immunodeficiency virus (HIV)-infected subjects in Japan, Chlamydia-specific antibodies in sera collected from 106 HIV-infected subjects were measured by the microimmunofluorescence test. The prevalence of C. pneumoniae-specific IgA, C. trachomatis-specific IgG and IgA and mean titers were significantly higher in the homosexual and heterosexual HIV-infected subjects than in the hemophilic patients and HIV-negative controls. These data indicate that the higher C. pneumoniae and C. trachomatis seroprevalence among HIV-infected subjects is probably due to an HIV risk factor, such as promiscuous sexual behavior, rather than to HIV infection itself.

Adolescent↗
PubMed2000

[Development of patient-friendly preparations(II): Preparation and characterization of carrageenan gel containing polyethylene (oxide)].

The pharmaceutical utility of the allopurinol gel (APNgel) which consists of allopurinol (APN), carrageenan (kappa-CG or iota-CG) and polyethylene (oxide) (Alkox) was investigated as a possible material for an oral dosage preparation for ease in handling and/or swallowing. The gel formation was studied as a function of a variety of the concentration of Alkox and/or CG added. The APNgel gelled with kappa-CG was not appropriate to the oral dosage form because of its original taste and odor. In contrast, since iota-CG has no odor and/or taste, we added iota-CG as a gel material. From the investigation of the gelation behavior and the handling of the gelled material, the preferred composition of APNgel (Alkox: iota-CG% ratio) seemed to be that of 0.5:2.0, 1.0:2.0 and 2.0:2.0. The gel strength and the in vitro assessment of the adhesiveness of APNgels were evaluated using a creep meter. The gel strength of the APNgel was affected by the amount of the added Alkox. From the in vitro assessment of the adhesiveness of APNgels, the adhesiveness of APNgel increased with an increase in the amount of added Alkox. The release behavior of APN from APNgels was investigated by the paddle bead method, mimicking the chewing action in mouth. The APNgel was sheared by the beads and the release of APN completed within 480 s. From the results of the sensory test, APNgel consisting of 2.0% iota-CG and 1.0% Alkox seemed to be favorite to the jelly-like preparation.

Adult↗
PubMed2000

Pharmacokinetic consideration on administration regimen of lamivudine in japanese patients infected with HIV-1.

OBJECTIVE: The typical regimen for lamivudine is 150 mg bis in die (bid). However, pharmacokinetic values of lamivudine will differ among individual patients. In addition, few studies regarding the pharmacokinetics of lamivudine in the Japanese people have so far been reported. Therefore, we have aimed to examine the variation in the pharmacokinetic values of lamiduvine present in six Japanese patients with HIV-1 infection. PATIENTS AND METHODS: Lamivudine concentrations were measured in three hemophiliacs (HIV-1-asymptomatic carrier, AC) and three non-hemophiliacs (2 of these patients were AC and one had AIDS-related complex, ARC). In order to simulate the lamivudine plasma concentrations found in chronic oral administration, we added an absorption compartment to the two-compartment model. RESULTS: The mean +/- SD of Tmax, Cmax, AUC(0 - infinity) and t1/2beta were 1.2 +/- 0.5 (hours), 1,280 +/- 267 (ng/ml), 6,778 +/- 2,763 (ng x h/ml), and 10.3 +/- 4.7 (hours), respectively. Although these values were comparable on average to those previously reported, there were noticeable differences with respect to the various time courses of drug plasma concentration among each patient. CONCLUSION: Computations speculated that the trough and peak plasma concentrations as well as the AUC at steady-state change significantly depending on each patient. It suggests that individual pharmacokinetic values of lamivudine should be determined before deciding the optimal administration dose for specific patients.

Adult↗
PubMed2000

[A case of acupuncture needle dermatitis].

A 65-year-old female visited our clinic with painful red vesicular dermatitis of the forehead and around the left eye. She had received acupuncture for headache and shoulder stiffness 6 days before visiting our clinic. A patch test with nickel sulfate gave positive results. We treated her with the greater occipital nerve block and trigger point injection which relieved her pain. We reached the diagnosis of greater occipital trigeminal syndrome with contact dermatitis from the acupuncture needle.

Acupuncture Therapy↗
PubMed2000

[Detection of rifampin-resistant Mycobacterium tuberculosis by line probe assay (LiPA)].

A recently described reverse hybridization-based line probe assay is used for the rapid detection of the mutations in the rpoB genes of rifampin-resistant Mycobacterium tuberculosis and for the identification of the M. tuberculosis complex. A multicenter study that included 5 laboratories was performed to evaluate the line probe assay in comparison with the in vitro susceptibility test. A total of 406 mycobacteria isolates which were composed of 103 rifampin-resistant and 230 rifampin-susceptible M. tuberculosis isolates, and 73 mycobacteria other than tubercle bacilli (MOTT), were subjected to this study. All 333 M. tuberculosis isolates were discriminated correctly from MOTT bacilli by a line probe assay. Concordance rates with sequencing results for five wild-type probes (S probes) and four specific mutations (R probes) for detecting the mutations in the rpoB genes were both 100%. The overall concordance rate with the in vitro susceptibility testing results was 98.5% (328 of 333 isolates). These results indicate that a line probe assay kit may be useful for the rapid diagnosis of rifampin-resistant tuberculosis.

Antibiotics, Antitubercular↗
PubMed1999

Distribution and developmental changes of adenylate kinase isozymes in the rat brain: localization of adenylate kinase 1 in the olfactory bulb.

Changes in the levels of three adenylate kinase isozymes (AK1, AK2, and AK3) in the rat brain during development were investigated by immunoblot analysis. The levels of AK1 and AK3 of the whole brain increased after birth, while AK2 was detected only in the early embryonic period. In the adult rat brain, high levels of AK1 were present in the olfactory bulb. Immunohistochemical analysis showed that AK1 was found predominantly in the olfactory nerve layer and the glomerular layer. In the olfactory bulb, AK1 gene expression was enhanced in the early postnatal days, whereas it remained low in the cerebellum during the first 10 postnatal days. These results suggest that the AK isozymes are involved in neuronal maturation and regeneration. The understanding of the physiological actions of adenosine and ATP as neurotransmitters/neuromodulaters in the central nervous system has improved. ATP and adenosine receptors have been found to be widely distributed over the whole brain, although the intra- and extracellular metabolism of these compounds has not been well elucidated.

Adenylate Kinase↗
PubMed1999

Effect of FR167653 on small bowel ischemia-reperfusion injury in dogs.

IL-1 and TNF-alpha are known to be pleiotropic cytokines associated with various inflammatory conditions such as small intestinal injury after ischemia-reperfusion. FR167653 has been characterized as a potent suppressant of IL-1 and TNF-alpha production. The effect of FR167653 on intestinal reperfusion injury was investigated in a warm ischemia model of the canine gut. Sixteen mongrel dogs were divided into two groups: a control group and a FR group to which FR167653 was administered. Both the superior mesenteric artery and vein were clamped for 2 hr. Arterial pH, hepatic venous hemoglobin oxygen saturation, intramucosal pH, and the survival rate were well maintained in the FR group in comparison with the control group after reperfusion. FR167653 inhibited the expression of IL-1beta mRNA. Histologically, ischemia-reperfusion injury was more severe in the control group than the FR group. This study suggests that FR167653 inhibits proinflammatory cytokines and ameliorates ischemia-reperfusion injury of the small intestine.

Animals↗
PubMed1999

Effects of cyclopiazonic acid on contraction and intracellular Ca2+ in oesophageal striated muscle of normotensive and spontaneously hypertensive rats.

1. The effects of cyclopiazonic acid (CPA), a selective inhibitor of sarcoplasmic reticulum (SR) Ca2+-ATPase, on twitch contraction and on the resting state of tension and intracellular Ca2+ level ([Ca2+]i) of the oesophageal striated muscle of stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar Kyoto rats (WKY) were compared. 2. CPA (10 micronM) augmented the twitch contraction of oesophageal striated muscle preparations from both SHRSP and WKY, reducing the rate of relaxation (-dT/dt), and thus resulting in the prolongation of the time to 80% relaxation. The effect was significantly smaller in the SHRSP preparations. 3. In the resting state, CPA caused a sustained elevation of [Ca2+]i. The elevation was greater in the WKY preparations. Tension development accompanied by the elevation was observed in WKY preparations, but not in SHRSP preparations. 4. The sustained elevation of [Ca2+]i induced by CPA was eliminated by the removal of extracellular Ca2+. Both the elevated [Ca2+]i and tension in the preparations from WKY were reduced by flufenamic acid (100 micronM), mefenamic acid (100 micronM), lanthanum (La3+, 100 micronM), gadolinium (Gd3+, 100 micronM) and SK&F 96365 (100 micronM) but not by verapamil (10 micronM). 5. Thapsigargin (3 micronM), another SR Ca2+-ATPase inhibitor, produced similar effects on basal tension to those of CPA, although it reduced the amplitude of twitch contraction. 6. These results suggest that in the rat oesophageal striated muscle, (1) CPA extends the sequestrating time of Ca2+ into the SR, (2) CPA induces a Ca2+ influx mediated through verapamil-insensitive pathways, possibly nonselective cation channels, and (3) the mechanism of [Ca2+](i) modulation due to CPA-sensitive SR Ca2+-ATPase is deteriorated in the oesophageal striated muscle from SHRSP as compared with WKY preparations.

Animals↗
PubMed1999

The hemagglutinating action of Vibrio vulnificus metalloprotease.

Vibrio vulnificus protease (VVP), a 45-kDa zinc metalloprotease, consists of two functional domains: an N-terminal 35-kDa polypeptide having endoproteinase activity, and a C-terminal 10-kDa polypeptide that mediates the binding of VVP to the erythrocyte membrane. Therefore, VVP, but not its N-terminal endoproteinase domain alone, has agglutinating activity to rabbit erythrocytes. When a single zinc atom in the catalytic center was substituted by treatment with CuCl2 or NiCl2, proteolytic and hemagglutinating activities were reduced by Ni substitution but not by Cu substitution. Cu-treated 35-kDa polypeptide showed sufficient affinity of the catalytic center and weak binding ability to the erythrocyte membrane, but the Ni-treated polypeptide did not. These results suggest that the binding of endoproteinase domain to membrane is also necessary for hemagglutination.

Animals↗
PubMed1999

Relationship between coronary blood flow velocity waveform and transmural distribution of myocardial blood flow in coronary artery.

It is important to know the transmural distribution of myocardial blood flow in assessing the severity of ischemia in coronary heart disease. We analyzed the relation between phasic waveform of epicardial coronary flow velocity with a Doppler flow probe in the left anterior descending artery in dogs and regional myocardial blood flow using a colored microsphere technique. Time-velocity integral in an average of 5 cardiac cycles was measured as an index of coronary blood flow during diastole (TVId) and systole (TVIs). The diastolic fraction of coronary blood flow (%DF) was defined as TVId/(TVId + TVIs). Myocardial specimens were divided into inner (subendocardial), middle, and outer (subepicardial) layers, and the inner layer to outer layer myocardial blood flow ratio (endo/epi ratio) was used as an index of transmural distribution of myocardial perfusion. The mean endo/epi ratio and the mean %DF decreased as the pressure gradient increased. There was a moderate but significant correlation (r = 0.57) between the endo/epi ratio and the %DF. In conclusion, analysis of the phasic pattern of coronary blood flow velocity provides some information about the transmural distribution of blood flow in the myocardium. The %DF may be a useful index for evaluating subendocardial ischemia.

Animals↗
PubMed1999

A synergistic effect of serotonin transporter gene polymorphism and smoking in association with CHD.

Serotonin induces vasoconstriction in the presence of atherosclerotic lesions. Platelets acquire serotonin from the extracellular space by serotonin transporter and release it following aggregation. There is a functional polymorphism in the serotonin transporter (5-HTT) gene promoter associated with transcriptional efficacy and plasma serotonin levels. To examine whether the polymorphism is associated with coronary heart disease (CHD) in the Japanese, we analyzed 144 male CHD patients with an onset age before 65 and 222 apparently healthy men. The L allele was observed significantly more frequently in the CHD patients (26%) than in the control subjects (19%); the odds ratio was 1.48 (p <0.03). A significant interaction between the polymorphism and smoking was observed for CHD (p = 0.03), suggesting that the two have a synergistic effect on CHD. Odds ratio of the combination of the L allele and smoking was 1.95 (p <0.003). The 5-HTT gene promoter polymorphism may play a role in susceptibility to CHD, particularly when it is combined with smoking.

Adult↗
PubMed1999

Association between serotonin transporter gene polymorphism and smoking among Japanese males.

The serotoninergic system may be involved in smoking behavior because nicotine increases brain serotonin secretion, nicotine withdrawal decreases serotonin levels, and a selective serotonin reuptake inhibitor antagonizes the response to nicotine. Compared with the L allele, the S allele of the polymorphism in the upstream regulatory region of the serotonin transporter gene is associated with decreased transcription efficiency of the 5-HTT gene promoter. We examined this polymorphism in a Japanese population consisting of 387 males from two different areas in Japan. The L allele was observed significantly more often in smokers (21%) than in nonsmokers (lifetime nonsmokers + ex-smokers, 14%; P = 0.005). The presence of the L allele (the L/L + L/S genotypes) was also significantly increased in smokers (37%) compared with that in nonsmokers (24%; P = 0.003). The present study suggests that individuals with the S/S genotype are less inclined to smoke and/or can more easily stop smoking than others, supporting a role of the serotoninergic system in smoking behavior.

Adult↗
PubMed1998

Intramucosal pH and intestinal mucosal damage in ischemia-reperfusion injury.

Small bowel transplantation (SBT) has become an increasingly promising treatment for short bowel syndrome. The evaluation of graft viability after SBT, however, has not been established, except by mucosal biopsy. We monitored intestinal mucosal acidity in order to detect small intestinal ischemia-reperfusion injury. Mongrel dogs were used in this study. After laparotomy, the small bowel was isolated with a vascular pedicle. A tonometer to measure intramucosal pH (pHi) was then positioned in the terminal ileum. The superior mesenteric artery was occluded with or without concomitant superior mesenteric vein occlusion for 60 or 120 min. The value of pHi was determined from laparotomy (baseline) to 12 h after reperfusion. Whole-thickness specimens of the ileum were taken before ischemia, just before reperfusion, and 1 h afterward. Mucosal injury was graded histopathologically. pHi decreased from baseline in relation to the degree of histopathological mucosal injury. There was a significant correlation between histological findings and the change in pHi. We conclude that monitoring intestinal mucosal acidity is a reliable way of determining graft viability after SBT.

Animals↗