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Biomedical subjects

N Ikeda

Publications and source records attributed to N Ikeda.

At least 181 records · Page 10Linked to original sources
PubMed1997

Arrhythmia curve interpretation using a dynamic system model of the myocardial pacemaker.

A problem of identifying the phase response curve of the myocardial pacemaker was investigated using a simple dynamic system model of cardiac arrhythmia. A hybrid optimization method of a genetic algorithm and a local optimization technique was employed to obtain a solution of the model fitting. The method was applied to two categories of arrhythmias, ventricular parasystole and high-degree AV block. The present study offered a new insight into the mechanism of cardiac arrhythmias.

Animals↗
PubMed1997

Plasma concentrations of antipsychotic drugs in psychiatric inpatients.

In current psychiatric therapy, two or more kinds of antipsychotic drugs are usually prescribed in Japan. However, there are few data on the therapeutic plasma concentrations of antipsychotic drugs or on the correlation between the daily dose and the plasma concentration, in cases where several antipsychotic drugs had been prescribed for each patient. We measured the therapeutic plasma concentrations of 9 antipsychotic drugs in 24 psychiatric inpatients during a 6-month period. They were treated with fixed dosages of antipsychotic drugs. Plasma samples were collected early in the morning once a month, and the concentrations of antipsychotic drugs were determined by gas chromatography with nitrogen phosphorus detection, high-performance liquid chromatography (HPLC) with fluorescence detection and HPLC with UV detection. The plasma levels of chlorpromazine, levomepromazine, thioridazine, haloperidol, bromperidol, zotepine, oxypertine, sulpiride and sultopride were 21.8-92.4, 31.7-156, 101-203, 16.4-56.2, 2.72-11.7, 13.6-84.0, 29.9-80.4, 70.1-1,120 and 35.7-2,990 ng/ml, respectively. A linear correlation between the daily dose and the plasma concentration was noted for sultopride, levomepromazine, sulpiride, haloperidol, chlorpromazine and zotepine.

Adult↗
PubMed1996

Novel insight into molecular mechanism of endotoxin shock: biochemical analysis of LPS receptor signaling in a cell-free system targeting NF-kappaB and regulation of cytokine production/action through beta2 integrin in vivo.

Lipopolysaccharide (LPS), a constituent of gram-negative bacteria cell wall, plays an essential role in the pathogenesis of septic shock by generating endogenous mediators such as cytokines, nitrous oxide, superoxide anions, and lipid mediators. In vitro, LPS induces the transcription of a set of genes involved in inflammatory reactions by activating several types of transcription factors, particularly nuclear factor-kappaB (NF-kappaB). An analysis of NF-kappaB activation using a cell-free system demonstated that two pathways converge to activate NF-kappaB; one is staurosporine-sensitive, the other is staurosporine-insensitive and tyrosine kinase-dependent. Furthermore, the latter pathway culminates in IkappaBalpha phosphorylation at serine/threonine residues in its carboxyl-terminal acidic region with dissociation of IkappaBalpha from NF-kappaB, thereby activating NF-kappaB. The requirement for the phosphorylation at this site was confirmed by the specific inhibition of NF-kappaB activation in a cell-free system by the synthetic peptide corresponding to this site. The in vivo administration of an anti-CD18 antibody prevented elevation of plasma tumor necrosis factor (TNF) levels and acute lethality induced by injection of a low dose of LPS into Propionibacterium acnes-primed rabbits or by the administration of a single high dose of LPS into animals. Anti-CD18 also prevented acute lethality induced by one of the main mediators of endotoxin shock, TNF-alpha. Furthermore, an antibody to a ligand for CD18, intercellular adhesion molecule-1, also prevented TNF-induced shock as well as endotoxin shock in rabbits. These observations suggest that the interaction between leukoytes and endothelium through beta2- integrin adhesion molecules may be of primary importance in mediating LPS signals in vivo.

Animals↗
PubMed1996

Epithelial cell proliferation during colonic chemical carcinogenesis in the rat.

To define the significance of alterations in epithelial cell proliferation as a marker of high risk mucosa for colorectal cancer, we examined cell proliferative events in the colonic mucosa during chemical carcinogenesis using in vitro bromodeoxyuridine labelling and by analysing serial colonoscopic biopsy specimens from dimethylhydrazine (DMH)-treated rats. In both the rectum and flexure of the colon, an increased labelling index of colonic epithelial cells, an upward extension of the proliferating zone and an upward shift of the major area of DNA synthesis of epithelial cells were observed during DMH-induced colonic carcinogenesis in rats. These changes preceded the development of the colonic tumour and were observed in endoscopically normal rectal mucosa where the tumour was absent. We confirmed the altered cell proliferative events preceding the development of the tumour by examining serial colonoscopic biopsies. The results suggest that these alterations are features that identify premalignant colonic mucosa in DMH-treated rats.

Animals↗
PubMed1996

[Quality evaluation on Paeoniae radix. I. Quantitative analysis of monoterpene glycosides constituents of Paeoniae radix by means of high performance liquid chromatography. Comparative characterization of the external figures, processing method and the cultivated areas].

The constituents of monoterpene in Paeoniae Radix were analyzed by means of high performance liquid chromatography (HPLC) using hitherto elucidated eight monoterpene glycosides, paeoniflorin 1, oxypaeoniflorin 2, benzoylpaeoniflorin, 3, benzoyloxypaeoniflorin 4, galloylpaeniflorin 5, galloyloxypaeoniflorin 6, albiflorin 7 and lactiflorin 8 and a monoterpene paeoniflorigenone 9. In sixty seven kinds of Paeoniae Radix collected in Japan, China, and South and North Korea those monoterpene constituents 1-9 were found to exist in the amounts of ranging 0.12-9.61% 1, 0.06-10.8% 2, 0.02-0.79% 3, 0.24-0.47% 4, 0.25-2.53% 5, 0.05-2.86% 6, 0.09-2.76% 7, 0.35-0.64% 8 and 0.01-0.49% 9 respectively. In addition, these results obtained by the quantitative analysis were discussed from the viewpoint of the external figures and processing methods.

China↗
PubMed1996

[The role of catalase in histologic changes of acute experimental pancreatitis].

We produced acute biliary reflux pancreatitis by an injection of auto-bile in 31 young mongrel dogs. We divided into control group (n = 10), catalase administration group (B1 group, n = 17) and no-administration group (B2 group, n = 14). We studied the histologic changes of the brain tissue in those groups. There was no significant difference in the survival rate between group B1 and B2. In the histologic findings, ischemic cell changes were dominant in both groups within one month, but after 3 or 6 months after operation in group B2, satellitosis and/or neuronophagia was recognized as the irreversible changes. The lipid peroxides level was significant high in group B2. Consequentially, it is natural to think that the production of free radicals have been inhibited by catalase and the histologic changes in the brain in group B1 have been light.

Acute Disease↗
PubMed1996

[The characteristics of clinical features of pulmonary tuberculosis in female].

We studied the clinical features of culture-positive, previously untreated patients with pulmonary tuberculosis (77 in females and 200 in males), with special reference on the gender differences in clinical features. The mean age was 50.8 y.o. for female and 54.4 y.o. for male, and the age distribution was almost similar to that of newly-registered patients of whole Japan in 1993, namely, small peak in 20s decade and large peaks in the age group over 50 in female, and gradual increase up to 50 years and get to plateau in male. Thirty-nine % in female and fifty-four % in male had various past histories and/or complications which might affect to the deterioration of tuberculosis, such as diabetes mellitus, liver function distress, respiratory failure, malignancy, stomach resection and so on. The rates with each complication were, in general, higher in male than in female. The positive rate to Mantoux reaction was higher in female than in male, and stronger reactions were observed in female than in male. According to the classification of pulmonary tuberculosis designed by the Japanese Society for Tuberculosis (GAKKAI classification), the site(s) of affected lung, the stage and the extent of lesions were more advanced in male than in female, and the positive rate and the amount of bacilli on smear were higher in male than in female. The most marked difference was the location of the main lesions, 80% in the apical and posterior segments of upper lobe (S1,2) and 8% in the superior segments of lower lobe (S6) in male, while 60% in S1,2 and 25% in S6 in female. The rate of complete resistance against to anti-tuberculosis agents was higher in male than in female, but the combination chemotherapy of isoniasid and refampicin with streptomycin or ethambutol was almost equally effective both in males and females, and almost all patients converted to bacilli negative within three months after the initiation of the chemotherapy, except in a few male patients.

Adult↗
PubMed1996

[DNA analysis of a case of so-called blood group chimerism].

A 46-year-old woman who has three children, whose red blood cells exhibit a dual population of groups A and B, was investigated. Her lymphocytes had an XX/XY karyotype and Y chromosome markers were detected from buccal cells and hair root cells in DNA analysis. Three bands were detected in D1S80 VNTR locus (MCT118), two bands from father and one from mother. Her ABO genotype should be genetically AO, however, the PCR-RFLP method revealed a pattern of BO genotype. From these findings, it is concluded that she is a so-called dispermic chimera which is the result of the fertilization by two sperms and that DNA analysis is useful for distinguishing between twin and dispermic chimerism.

ABO Blood-Group System↗
PubMed1996

[A case report of volatile solvent psychosis].

A case (male, 27 years old) with chronic thinner intoxication, whose mental condition was reexamined in accord with a court order, is reported. He had been sniffing thinner from age 12 to 27. Since the age of 17, he experienced visual and auditory hallucinations without sniffing thinner. He had no family history of schizophrenia. The psychiatric examination revealed that he had positive symptoms of schizophrenia, especially the first rank symptoms, such as auditory hallucinations (i.e. voices commenting and voices arguing), experience of influence (withdrawal of thought, thought insertion and influence of thought) and delusional perception, but did not show negative symptoms (i.e. blunting thought). Furthermore, he could maintain good emotional contact with others. Hallucinations, which appeared in acute intoxication with thinner, were second rank symptoms, different from those observed in the sober period when he was not under the influence of the thinner. Judging from above facts it was difficult to diagnose this case as schizophrenia or the flashback phenomenon of thinner dependence. Although the disease concept of volatile solvent psychosis has not been clearly established, this case may suggest that the first rank symptoms are important manifestations of volatile solvent psychosis.

Adult↗
PubMed1996

[A case of tuberculous infection of emphysematous bulla in the superior segment of left lower lobe].

We report a case of tuberculous infection of emphysematous bulla, who is a 71-years-old male and ex-smoker. He had no past-history and had been treated for chronic obstructive pulmonary disease. At the periodical consultation on Sept 28 '95, abnormal shadow was found in left middle lung field on plain chest X-ray without any exacerbation of symptoms. Nearly alllaboratory tests on admission were within normal limit, except of slight elevation of inflammatory markers and slight hypoxemia. The Mantoux's skin test was positive. Roentogenologically, the air-fluid level was detected in the bulla of superior segment of left lower lobe. By percutaneous thoracentesis of the bulla under fluoloscopy and ultrasonic echo-guide, the fluid in the bulla was obtained. The fluid was exudate, the activities of ADA and LDH were elevated, but neutrophils were more dominant than lymphocytes in the fluid. The MTD test was positive, which amplifies rRNA of Mycobacterium tuberculosis (MTB), and MTB were cultered after four weeks from the fluid. However, MTB was not cultured from sputum and bronchial washing of left S6 via bronchoscope. After the administration of RFP, INH and EB, the fluid gradually disappeared with reduction of the size of bulla. We discussed the usefulness of the examination of the fluid in the bulla, especially the measurement of the activity of ADA and the MTD test for the confirmation of diagnosis as tuberculosis.

Adenosine Deaminase↗
PubMed1996

[Forensic application of biochemical blood analysis--studies on CPK and LDH isozymes].

We analyzed CPK and LDH isozymes of the plasma of cadavers, which give indication of muscle damage in normal blood. The isozyme patterns in cadaveric plasma were different from those in normal plasma. The patterns were classified into five groups in CPK and four groups in LDH, respectively. We could not detect obvious correlation between the cause of death and each classified groups in CPK. In comparison with CPK, we detect the clear relation between the cause of death and isozyme patterns in LDH. All cases of LDH 1 and 5 predominant or LDH 1, 2 and 5 predominant groups had myocardial infarction or other myocardial damage. So LDH isozyme pattern was informative for antemortem cardiac conditions of the cadaver and considered to be useful for conjecturing myocardial damage of the cadaver at least within 24 hours after death.

Blood Chemical Analysis↗
PubMed1996

Training examiners for a national epidemiological survey of oral mucosal lesions.

Ensuring the validity and reliability of data collected in epidemiological surveys is an important consideration. The purpose of the present report is to describe a training and calibration programme for 16 examiners taking part in a national survey of oral mucosal lesions and to present an evaluation of the results. The programme included the distribution of a pictorial manual to participants and a series of lectures followed by three diagnostic sessions, two using slides and the last involving patients. At the final session, the trainees classified 88 per cent of 16 patients correctly in comparison with the definitive diagnoses of the trainer, and their sensitivity on recording oral carcinoma, leukoplakia and lichen planus was at least 0.88. However, correctly classifying submucous fibrosis on the basis of slides alone proved problematic. At the conclusion, the diagnostic accuracy of two examiners for all types of lesion remained appreciably lower than the majority. Training strategies for various types of study are discussed. The method reported is considered to represent a model approach to training and calibrating examiners for this type of survey work.

Dental Health Surveys↗
PubMed1995

Prevention of endotoxin shock by an antibody against leukocyte integrin beta 2 through inhibiting production and action of TNF.

Septic shock remains a serious disorder associated with high mortality. Accumulating evidence indicates that TNF is a major and essential mediator of endotoxin shock. We report here that administration of an antibody against CD18 dramatically reduced endotoxin-induced shock in rabbits as revealed by prevention of severe hypotension, metabolic acidosis and a pathological change suggestive of disseminated intravascular coagulation with concomitant inhibition of elevation of plasma TNF activity. The anti-CD18 antibody also inhibited the hypotension induced by administering recombinant TNF. Furthermore, an antibody against a ligand for CD18 complexes, intercellular adhesion molecule-1, also prevented TNF-induced shock as well as endotoxin shock in rabbits. These observations suggest that adhesion of leukocytes to endothelium may be of primary importance in the action of TNF as well as in the production of TNF in vivo and that the antibody against adhesion molecules could be of therapeutic benefit in life-threatening septic shock in humans.

Acute-Phase Reaction↗
PubMed1995

Prevalence study of oral mucosal lesions in a selected Cambodian population.

The aim of this study was to investigate the epidemiology of oral mucosal lesions in a selected Cambodian population to obtain pilot data useful in planning an oral health data base for the country. Due to unstable conditions in Cambodia, the validity of population data related to present census information is highly questionable. Therefore, prior to this investigation a census registration was carried out using local health workers as registrars in nine villages of a commune. In the period July 4-31, 1991, a total of 1319 individuals (953 women, 366 men, 15-99 yr) were examined by one oral surgeon in the nine villages of Kok Trop Commune, Kandal Stung District, southwest of the capital Phnom Penh. Clinical diagnoses were based on WHO criteria. Information on smoking habits, betel nut chewing habits, and alcohol use was collected by 4 Khmer dental personnel. In total, 71 lesions were recorded in 64 (4.9%) individuals. Leukoplakia was found in 1.1%, lichen lesions in 1.8%, candidosis in 1.4%, submucous fibrosis in 0.2%, cancer in 0.1% and other diagnoses in 0.8%. The prevalence of leukoplakia was 2.2% and 0.6% among men and women respectively, a statistically significant difference (P < 0.05). There were significantly more smokers (P < 0.01) among subjects with leukoplakia (64.3%) than among those without this lesion (28.6%). All subjects with lichen lesions were women. The age-adjusted relative risk for developing lichen among betel nut chewers as compared to non-chewers was 3.3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Serotypes and antimicrobial susceptibility of Streptococcus pneumoniae from clinical specimens].

Studies were made on 66 strains of Streptococcus pneumoniae which were obtained from clinical specimens in 1991 through 1993 and showed 19 mm or less of disk inhibition zone diameter (DIZD) against 1 microgram oxacillin (MPIPC) disk. The studies included the determination of their serotypes, antimicrobial susceptibility, and comparison between microbroth dilution (MD) method and Kirby-Bauer (K-B) method. In the study of distribution of serotypes, additional 32 strains which showed 20 mm or more in DIZD were included for study. The results were as follows. 1) About 70% of 98 strains of S. pneumoniae were serotyped by 6 kinds of antisera. Among penicillin-susceptible S. pneumoniae (PSSP), type 3 were 20.6%, type 19, 15.9%, type 6, 14.3%, type 18, 9.5%, type 14, 7.9%, and type 4, 1.6%. Among penicillin-intermediate S. pneumoniae (PISP), and penicillin-resistant S. pneumoniae (PRSP), type 19 were 60%, and type 18, 8.6%. In PISP and PRSP, more than half were type 19, which indicates they are distinctly different from PSSP in serotypical distribution. 2) As to the difference between screening by MPIPC disk and minimum inhibitory concentration (MIC) by benzylpenicillin (PCG), among 66 MPIPC resistant strains, PSSP strains were 31 in number (47%). 3) MIC showed that PISP and PRSP strains were more resistant than PSSP against cefaclor (CCL), cefazolin (CEZ), cefotiam (CTM), cefotaxime (CTX), imipenem (IPM), minocycline (MINO), and erythromycin (EM), but no difference was found in the 2 groups of strains in MIC with clindamycin (CLDM) and ofloxacin (OFLX). 4) All type 3 strains formed mucoid colonies and were resistant to MINO and highly resistant to EM and CLDM. 5) By NCCLS, category of antimicrobial susceptibility is determined against CCL, EM, OFLX, in MD method and K-B method. Against these antibiotics, the complete agreement rates were 75.8%, 92.4% and 86.4% respectively.

Cefaclor↗
PubMed1995

Prevention of endotoxin-induced acute lethality in Propionibacterium acnes-primed rabbits by an antibody to leukocyte integrin beta 2 with concomitant reduction of cytokine production.

Acute lethality was induced in rabbits by the sequential injection of Propionibacterium acnes and lipopolysaccharide (LPS). P. acnes induced the infiltration of inflammatory cells into the liver lobules during the early phase, and LPS in the late phase caused death in association with pathological changes mimicking hepatocellular necrosis or degeneration around infiltrated mononuclear cells and fibrin deposition in the liver, lung, and kidney, suggestive of a systemic Schwartzman-like reaction. These pathological changes were accompanied by the elevation of plasma tumor necrosis factor (TNF) and interleukin-8 (IL-8) levels. A neutralizing antibody to a leukocyte adhesion molecule, integrin beta 2 (CD18), administered at the time of LPS challenge, prevented reduced the elevation of plasma TNF and IL-8 levels. An anti-TNF alpha antibody but not an anti-IL-8 mediator in this model. These results indicate that CD18 is critically involved in vivo in activating leukocytes to produce cytokines in response to LPS.

Animals↗
PubMed1995

The occurrence of nicked human chorionic gonadotropin (hCG) by a thermolytic endoprotease.

A nicked form of human chorionic gonadotropin (nicked hCG), in which only one peptide bond between residues 47 and 48 (-Gly-Val-) of beta-subunit is cleaved, has been found in the urine and blood of pregnant women. In this study, we investigated the occurrence of nicked hCG and the localization of the nicking enzyme for hCG. First, to determine what type of protease nicks hCG, an in vitro proteolytic study using various proteases was performed. Amino-terminal amino acid sequence analysis of the beta-subunit purified from protease-treated hCG indicated that thermolysin actively nicks hCG. Secondly, to determine which tissues are related to the formation of nicked hCG, the distribution of radioactivity in various tissues after i.v. administration of radiolabeled hCG to female rats was examined. The radioactivity accumulated predominantly in the kidney (17%), liver (9.3%) and ovary (0.9%) after 30 min of injection. Analysis of molecular species of beta-radiolabeled hCG in various tissues and body fluids, using sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by autoradiography, indicated that a nicked hCG-like molecule was found in the kidney, predominantly, as well as in the serum and urine. To examine the role of the kidney in producing nicked hCG, hCG was incubated with rat kidney particulate fraction (KPF). Immunoblot analysis of KPF-treated hCG indicated that KPF produced a nicked hCG-like molecule. Furthermore, the possibility that placental trophoblast cells produce nicked hCG was also examined using the choriocarcinoma cell BeWo.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗