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Biomedical subjects

K Katayama

Publications and source records attributed to K Katayama.

At least 235 records · Page 13Linked to original sources
PubMed1995

Mononucleosis-like illness in an infant associated with human herpesvirus 6 infection.

Illnesses resembling mononucleosis, hematologically characterized by atypical lymphocytosis in the peripheral blood, are caused by other viral infections as well as by a primary Epstein-Barr virus infection. Human herpesvirus 6, a newly isolated member of the herpesvirus group, can also cause a mononucleosis-like illness. Illness associated with human herpesvirus 6 infection mostly occurs in immunocompetent adults. We observed a 3 month old infant who presented with marked atypical lymphocytosis and liver dysfunction. We examined serum samples to detect viral antibodies related to mononucleosis-like illness. Only the titers of antibody against human herpesvirus 6 were elevated. Primary human herpesvirus 6 infection cannot only cause exanthem subitum or present in an inapparent form but can also cause an illness like mononucleosis, even in an infant.

Herpesviridae Infections↗
PubMed1995

Stable expression and coupling of cardiac L-type Ca2+ channels with beta 1-adrenoceptors.

A number of neurotransmitters modulate cardiac dihydropyridine-sensitive L-type Ca2+ channels through several homologous G protein-coupled receptors. Previous studies that have examined receptor-Ca2+ channel interactions have suffered because of the coexpression of various receptor subtypes in native cells. To study the functional coupling of a particular receptor subtype to these channels, rabbit cardiac Ca2+ channel alpha 1 and skeletal beta and alpha 2/delta subunits were stably expressed in baby hamster kidney cells. In this stable cell line, Ca2+ channels remained at high levels (> 1000 fmol/mg protein, or 2700 channels per cell) over extended times. The expressed recombinant Ca2+ channels displayed the voltage dependence of activation and inactivation, unitary conductance, and pharmacology characteristic of native cardiac L-type Ca2+ channels. Subsequent coexpression of the beta 1-adrenoceptors (150 to 300 fmol/mg protein) with the Ca2+ channels resulted in cell responsiveness to the extracellular application of isoproterenol. These results indicate that heterogeneous expression in mammalian cells provides a useful system for studying both biophysical analysis of Ca2+ channel properties and receptor-coupled regulatory processes.

Animals↗
PubMed1995

Pharmacokinetic and pharmacodynamic studies of centrally acting drugs in rat: effect of pentobarbital and chlorpromazine on electroencephalogram in rat.

Electroencephalogram (EEG) alterations in rat after the i.v. administration of pentobarbital (PTB) and chlorpromazine (CPZ) were measured by power spectral analysis. The time courses of PTB concentrations in plasma, cerebrospinal fluid (CSF) and brain were determined after the i.v. administration of PTB (20, 40 mg/kg) by GC-MS. The PTB concentrations in plasma, CSF and brain could be described by a biexponential equation, a CSF model and a blood flow limited model, respectively. The relationship between the alteration of EEG and the PTB concentrations in the CSF or brain or the effect compartment were analyzed using the sigmoid Emax model. The alteration of EEG after PTB administration could be described by the PTB concentration in these compartments using the sigmoid Emax model. These results indicated that the site of action for the alteration of EEG after PTB administration is in instantaneous equilibrium with the CSF, the brain and the effect compartment. Thus, alterations in EEG after PTB administration can be predicted by monitoring the total PTB concentration in plasma. The alteration of EEG after i.v. administration of CPZ (4 mg/kg) showed a two-phase variation. Although the relationship between the alteration of EEG and the CPZ concentrations in CSF or the striatum or the effect compartment (total and free drug) were analyzed using the linear model, the Emax model or the sigmoid Emax model, the two-phase alteration of EEG after CPZ administration could not be described by any of these models. These results indicated that the pharmacokinetic and pharmacodynamic modeling of CPZ during the alteration of EEG may be complicated due to several pharmacokinetic and pharmacodynamic factors, such as an alteration of the free fraction of CPZ in the striatum, the formation of active metabolites, and two different intrinsic effects of CPZ on the EEG (one in an increase and the other in a decrease of the brain's electrical activity.

Animals↗
PubMed1995

[Study on baths with crude drug. II.: the effects of coptidis rhizoma extracts as skin permeation enhancer].

Skin permeation and its enhancing activity of Coptidis Rhizoma (Coptis japonica Makino) were studied in regard to its application as a bath agent. As a result, methanol extracts and three alkaloids (berberine, coptisine, and palmatine isolated from Coptidis Rhizoma) enhanced effectively the skin permeation of 5-fluorouracil, which is taken as a hydrophilic permeant. Furthermore, it was observed that diffusion coefficient is almost constant on the skin permeation of 5-fluorouracil and was also observed that these three kinds of alkaloids did not penetrate through the skin, but adsorbed into the skin. These results suggest that these three protoberberine type alkaloids increase the concentration of polar drugs in the skin and enhance the skin permeation similarly to surfactants.

Animals↗
PubMed1995

The effect of left ventricular chamber compliance on early diastolic filling during coronary reperfusion.

This study was designed to assess the changes in left ventricular (LV) diastolic filling and to evaluate the dynamic determinants of LV diastolic filling during coronary reperfusion after acute myocardial ischemia. We examined LV diastolic pressure-volume relations (D-PVRs) using the conductance catheter technique with a high-fidelity micromanometer, and the transmitral flow using transesophageal pulsed Doppler echocardiography in 9 open-chest anesthetized dogs with the pericardium opened. We measured early diastolic peak flow velocity (E), late diastolic peak flow velocity (A), the ratio of peak E to peak A (E/A), operational chamber compliance at the minimum LV pressure [(dV/VdP) nadir], and the time constant of LV relaxation (TC). Acute regional myocardial ischemia was produced by occluding the proximal portion of the left anterior descending coronary artery. Data were acquired at baseline, 10 min after acute myocardial ischemia, and after 15 and 90 min of reperfusion under left atrial pacing at 100 beats/min. During myocardial ischemia, D-PVRs shifted upward and rightward on the same curvilinear relationship compared with that at baseline (LV end-diastolic pressure (LVEDP) from 7.3 to 10.5 mmHg, LVEDV from 25 to 31 ml, both p < 0.01), accompanied by a decrease in peak E and E/A (E from 41 to 25 cm/sec, E/A from 1.7 to 1.1, both p < 0.01) and a prolongation of TC (from 25.4 to 30.3 msec, p < 0.01). After coronary reperfusion, D-PVRs returned to baseline accompanied by an improvement in the peak E and E/A ratio. No significant changes in peak A were observed in any of the stages. There was no correlation between peak E and TC, however, a significant positive correlation was observed between peak E and (dV/VdP) nadir (r = 0.76, p < 0.01). In conclusion, this study demonstrated that, using pulsed Doppler echocardiography, the improvement of diastolic filling after coronary reperfusion was based mainly on changes in early diastolic filling, and that LV operational chamber compliance at early diastole, rather than a LV relaxation property, might play an important role in determining early diastolic filling during coronary reperfusion.

Analysis of Variance↗
PubMed1995

[Cisapride, a gastroprokinetic agent, binds to 5-HT4 receptors].

The affinity of cisapride for 5-HT4 receptors was investigated in comparison with those of other 5-HT4 receptor agonists and antagonists, such as 5-HT, 5-MeOT, mosapride, zacopride, metoclopramide, BIMU8, GR113808, SDZ 205-557 and ICS 205-930. Cisapride and the other compounds dose-dependently inhibited specific 3H-GR113808 binding to 5-HT4 receptors in guinea pig striatal membranes, and complete inhibition of specific 3H-GR113808 binding was achieved at the high concentrations of these compounds. Cisapride was 1.9-, 7.3-, 4.3-, 11- and 26-fold more potent than 5-HT, 5-MeOT, mosapride, zacopride and metoclopramide, respectively, in competing for 5-HT4 receptors. To determine the manner of interaction between cisapride and 5-HT4 receptors, Scatchard analysis of 3H-GR113808 specific binding to striatal membranes was performed. Cisapride increased the Kd value of 3H-GR113808 in striatal membranes in a dose-dependent manner without any influence on the binding density (Bmax) of 3H-GR113808. These findings indicate that cisapride binds to 5-HT4 receptors competing with 3H-GR113808 in guinea pig striatal membranes.

Animals↗
PubMed1995

The significance of immunoglobulin M antibody response to hepatitis C virus core protein in patients with chronic hepatitis C.

The significance of immunoglobulin (Ig) M antibody to hepatitis C virus core protein (IgM anti-HCV core) was studied in 41 patients with chronic hepatitis C virus (HCV) infection diagnosed by the polymerase chain reaction (PCR). IgM anti-HCVcore was tested with a solid-phase enzyme-linked immunoassay. The results were correlated with clinical features, liver histology findings evaluated by the histological activity index, and virological features such as genotypes and viremic levels assessed by a branched DNA assay. IgM anti-HCVcore was found in 29 (71%) patients, and its occurrence was only related to viremic levels. A significant relationship was observed between viremic levels and IgM anti-HCVcore cut-off index (rs = .42, P < .01). Of the eight low viremic (branched DNA-negative) patients, only two (25%) tested positive for IgM anti-HCVcore with a low cut-off index of < 3, whereas 27 (82%) of the 33 highly viremic (branched DNA-positive) patients had IgM anti-HCVcore (P < .01). After a 28-week interferon-alpha course (IFN-alpha), sustained aminotransferase normalization after therapy withdrawal was achieved by only two (13%) of the 16 patients with IgM anti-HCVcore cut-off index > 3 compared with 11 (44%) of the 25 patients with that < 3 (P < .05). IgM anti-HCVcore cut-off index decreased after therapy in patients who cleared the virus in sera but increased again after reappearance of viremia. These findings suggest that IgM anti-HCVcore may serve as a simple serological indicator of active virus replication and have relevance to the outcome of antiviral therapy.

Adult↗
PubMed1995

[A case of duodenal duplication and a review of reported cases].

We report a case of duodenal duplication and review of literatures on 43 cases reported in Japan including ours. A 34-year-old female who was admitted with chief complaints of epigastric pain and hematoemesis. An endoscopic examination and a hypotonic duodenography revealed a protruding tumor with bleeding ulcer. Wedge resection of the duodenum, including the lesion, was performed. A diagnosis of duodenal duplication was made by histopathological examination.

Adult↗
PubMed1995

Ability of prolonged interferon treatment to suppress relapse after cessation of therapy in patients with chronic hepatitis C: a multicenter randomized controlled trial.

The aim of this study was to determine whether 12 months course of interferon alfa (IFN-alpha) therapy could improve the beneficial effect of IFN in chronic hepatitis C. Eighty-eight patients were treated with natural IFN-alpha for either 28 weeks (45 cases) or 52 weeks (43 cases). Sustained response was achieved in 15 (33.3%) of 45 cases treated for 28 weeks and in 23 (53.5%) of 43 cases treated for 52 weeks. Transient response with relapse of alanine transaminase (ALT) after completion of therapy was observed in 13 cases (28.9%) treated for 28 weeks and in 4 cases (9.3%) treated for 52 weeks. Thus, ALT relapse was suppressed by prolonged IFN treatment. No response was found in 17 cases (37.8%) treated for 28 weeks and in 16 cases (37.2%) treated for 52 weeks, indicating that approximately 38% of the patients with chronic hepatitis C were resistant to IFN therapy even with prolonged treatment. The rate of sustained response was significantly higher in patients with type 2a or 2b than in those with type 1b. Even in type 1b cases, it was higher in the 52-week treatment group than in the 28-week treatment group, and the rate of transient response was lower in the 52-week treatment group, indicating that relapse in type 1b cases was suppressed by prolonged IFN therapy. IFN therapy was not effective for patients with advanced liver fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Prostatic acid phosphatase assay with self-indicating substrate 2,6-dichloro-4-acetylphenyl phosphate.

We characterized six self-indicating substrates, synthesized as the derivative compounds of acetylphenyl phosphate, for serum prostatic acid phosphatase (PAP) activity. One of the substrates, 2,6-dichloro-4-acetylphenyl phosphate (DCAPP), is superior to others in terms of stability, affinity, and low Km for PAP. The hydrolyzed product, 2,6-dichloro-4-acetylphenol (DCAP), has a maximum absorption at 334.2 nm, a pKa of 4.15, and a molar absorptivity at 340 nm of 21,490 L.mol-1.cm-1 in citrate-HCl buffer, pH 5.4. PAP activity was assessed by subtracting tartaric acid-inhibited acid phosphatase activity from total acid phosphatase activity. Our assay system involving DCAPP is a unique kinetic method that shows good reproducibility, wide analytical dynamic range, and high specificity for PAP. Moreover, it is easily adaptable to automated analyzers because the product, DCAP, can be monitored at 340 nm.

Acid Phosphatase↗
PubMed1995

[Relationship between prognosis and electrocardiographic characteristics in patients with left bundle branch block].

The purpose of this study is to investigate the electrocardiographic characteristics that determine the prognosis in patients with CLBBB. This study included 42 patients with CLBBB who could be followed up more than 5 years. 18 patients had no structural heart disease (group A), and 24 patients had structural heart disease (group B). 12 leads ECG and body surface mapping were recorded in all patients. Cardiac event was observed in 17 patients, and 16 of them were in group B, VAT in middle back was statistically longer in cardiac event group than non cardiac event group. In group B, VAT in middle back was also statistically longer in cardiac event group. Prolongation of VAT in middle back, prolongation of QRS duration, abnormality of QRS isopotential map, and abnormality of QRST isointegral map were useful indices for predicting cardiac event in patients with CLBBB.

Aged↗
PubMed1995

[Body surface mapping in patients with hypertrophic cardiomyopathy (HCM)].

The purpose of this study is to investigate the electrocardiographic indices that estimate the site of myocardial hypertrophy and the presence of ventricular tachyarrhythmia in patients with HCM. This study included 43 patients, 11 of them had episodes of ventricular tachyarrhythmia (9; sustained ventricular tachycardia, 2; ventricular fibrillation). Three patterns of QRS isopotential map were observed, each was characterized with apical, septal, and dilated phase HCM. VAT in left lateral chest to left back was statistically longer in patients with ventricular tachyarrhythmia. QRS isopotential map was useful for estimating the site of myocardial hypertrophy, and VAT ischrone map was useful for predicting ventricular tachyarrhythmia in patients with HCM.

Body Surface Potential Mapping↗
PubMed1995

[Hemoptysis due to aortopulmonary fistula: a case report of successful surgical treatment].

A 76-year-old man was admitted for recurrent hemoptysis of 3 weeks' duration. Chest X-ray revealed lung emphysema, but no findings of thoracic aortic aneurysm. The patient's physician attributed to bronchoectasia, and he underwent angiography for the purpose of embolization of bronchial arteries. Angiography showed a small saccular thoracic descending aortic aneurysm and an aortopulmonary fistula. So aneurysmectomy and patch angioplasty was done under partial cardiopulmonary bypass. Lobectomy or wedge pulmonary resection was not necessary. His postoperative course was uneventful. In case of the patients with hemoptysis, the possibility of aortopulmonary fistula should be considered, and computed tomography or aortography should be done to rule out other pulmonary diseases.

Aged↗
PubMed1994

Stable expression of the neuronal BI (class A) calcium channel in baby hamster kidney cells.

Plasmids containing the BI (alpha 1) cDNA with the dihydrofolate reductase (DHFR) gene, skeletal muscle alpha 2-subunit cDNA with the neo marker gene, and beta-subunit cDNA were co-transfected into baby hamster kidney (BHK) cells. BHK cells lack endogenous calcium channel activity. Twenty percent of the methotrexate (MTX) and G418 resistant clones were found to express calcium channel activity using the patch-clamp technique. A single clone, BHKBI147, demonstrated stable electrophysiological characteristics over 20 passages. Ca2+ currents of the BI channel in BHKBI147 cells were largely blocked by a specific P-type blocker, omega-AgaIVA, with an IC50 of 150 nM. Unlike the BI channel, Ca2+ currents of cardiac L-type channels expressed in BHK cells were completely blocked by the L-type antagonist, nifedipine, with an IC50 of 56 nM.

Animals↗