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Biomedical subjects

T Katoh

Publications and source records attributed to T Katoh.

At least 55 records · Page 3Linked to original sources
PubMed2001

Auditory evoked potential index predicts the depth of sedation and movement in response to skin incision during sevoflurane anesthesia.

BACKGROUND: The auditory evoked potential (AEP) index, which is a single numerical parameter derived from the AEP in real time and which describes the underlying morphology of the AEP, has been studied as a monitor of anesthetic depth. The current study was designed to evaluate the accuracy of AEPindex for predicting depth of sedation and anesthesia during sevoflurane anesthesia. METHODS: In the first phase of the study, a single end-tidal sevoflurane concentration ranging from 0.5 to 0.9% was assigned randomly and administered to each of 50 patients. The AEPindex and the Bispectral Index (BIS) were obtained simultaneously. Sedation was assessed using the responsiveness portion of the observer's assessment of alertness-sedation scale. In the second phase of the study, 10 additional patients were included, and the 60 patients who were scheduled to have skin incisions were observed for movement in response to skin incision at the end-tidal sevoflurane concentrations between 1.6 and 2.6%. The relation among AEPindex, BIS, sevoflurane concentration, sedation score, and movement or absence of movement after skin incision was determined. Prediction probability values for AEPindex, BIS, and sevoflurane concentration to predict depth of sedation and anesthesia were also calculated. RESULTS: The AEPindex, BIS, and sevoflurane concentration correlated closely with the sedation score. The prediction probability values for AEPindex, BIS, and sevoflurane concentration for sedation score were 0.820, 0.805, and 0.870, respectively, indicating a high predictive performance for depth of sedation. AEPindex and sevoflurane concentration successfully predicted movement after skin (prediction probability = 0.910 and 0.857, respectively), whereas BIS could not (prediction probability = 0.537). CONCLUSIONS: Auditory evoked potential index can be a guide to the depth of sedation and movement in response to skin incision during sevoflurane anesthesia.

Acoustic Stimulation↗
PubMed2001

Multicenter prospective nonrandomized study of long-term antiarrhythmic drug therapy in patients with tachyarrhythmias: Japanese Antiarrhythmics Long-Term Study-2 (JALT-2 Study).

Based on the results of the Cardiac Arrhythmia Suppression Trial (CAST), strategies for the treatment of tachyarrhythmias have changed rapidly. The Japanese Antiarrhythmics Long-Term (JALT) study was planned to investigate the present methods for choosing antiarrhythmic drugs, and the effects on long-term prognosis in patients with tachyarrhythmias in Japan. Following a 6-month preliminary study (JALT-1), there was a multicenter nonrandomized prospective study (JALT-2), with a 2-year follow-up, of patients with paroxysmal atrial fibrillation (PAF), sustained ventricular tachycardia (SVT) and nonsustained VT (NSVT). Four hundred fifty-five patients were registered, and 361 of them (79%) were analyzed. Cerebral infarction occurred in 10 of 193 patients (5.2%) with PAF. Transition to chronic AF was observed in 21 patients (10.9%), but in none of the patients receiving Ca antagonist therapy. Twenty-five patients died: 5 deaths were arrhythmic, 10 were because of pump failure, and 9 were noncardiac. The most significant difference in drug selection between JALT-1 and JALT-2 was the increase in the use of slow kinetic Na channel blockers for PAF and the decrease in the use of the same agents for VT in the JALT-2 study. A marked change of therapeutic strategy occurred in JALT-2 compared with JALT-1. Most patients with a poor prognosis had underlying heart diseases and heart failure, but the per annum rate of death by arrhythmia and pump failure in JALT-2 was less than that in JALT-1.

Adult↗
PubMed2001

Non-invasive diagnosis of concealed Wolff-Parkinson-White syndrome by detection of concealed anterograde pre-excitation.

Electrophysiological findings suggest that concealed anterograde conduction through accessory pathways may exist even during sinus rhythm in patients with so-called concealed Wolff-Parkinson-White (WPW) syndrome. To evaluate the pre-excitation characteristics in various types of WPW syndrome, high-resolution electrocardiograms were analyzed in 81 consecutive WPW syndrome patients and 50 age-matched normal subjects. The WPW group consisted of 30 cases of concealed WPW diagnosed by electrophysiological study, 38 cases of manifest WPW in which apparent delta waves were constant, and 13 cases of intermittent WPW in which the delta waves appeared periodically. The duration of the low-amplitude, high-frequency components of the signal-averaged filtered QRS complex that preceded the earliest upstroke of the surface QRS, including any delta waves (preceding potential duration, PPD), and the duration of low amplitude signals less than 10 microV (I-LAS10) or 20 microV (I-LAS20) were measured as parameters of pre-excitation. The PPDs in concealed and intermittent WPW were both significantly longer than in manifest WPW or in control subjects (6.8+/-2.7 ms, 7.9+/-3.5 ms vs 2.3+/-3.2 ms, 1.0+/-1.6 ms, both p<0.0001). Abnormally prolonged PPDs (>4 ms) were observed in 90% of concealed WPW cases and 76.9% of intermittent WPW, but in only 4% of normal subjects and 31.6% of manifest WPW. Both I-LAS10 and I-LAS20 in the 3 types of WPW syndrome were significantly longer than in normal subjects. The initial portion of the filtered QRS in concealed WPW closely resembled that of intermittent WPW. These results strongly suggest that in concealed WPW anterograde conduction through accessory pathways does occur and produces small amounts of pre-excitation even during sinus rhythm. The study concluded that, despite its name, concealed WPW is not completely concealed, and that non-invasive diagnosis during sinus rhythm is possible by using high-resolution electrocardiography to detect the concealed anterograde pre-excitation.

Electrocardiography↗
PubMed2001

Molecular phylogeny of butterflies Parnassius glacialis and P. stubbendorfii at various localities in East Asia.

The phylogeny of butterflies, Parnassius stubbendorfii and P. glacialis, collected at various localities in the Japan archipelago and the eastern part of the Asian continent was analyzed using mitochondrial DNA sequences coding for NADH dehydrogenase subunit 5 (805 bp). The molecular phylogenetic trees revealed that P. glacialis and P. stubbendorfii diverged from a common ancestor, and then the populations inhabiting the Japan archipelago and the Asian continent diverged in each species. The reliability of these divergences was supported by high bootstrap values. The divergences within the Japan archipelago and within the Asian continent in each species were unclear because of low bootstrap values. The genetic distance and a rough time-estimation in the UPGMA tree suggest that the both populations of P. glacialis and P. stubbendorfii may have been isolated in the Japan archipelago at the early time (about 1.7-2.0 Mya) of the glacial period in the Pleistocene. The genetic distance between the Japanese and the continental subspecies may be large enough that they can be classified as different species, in comparison with the genetic distances among some other parnassian species.

Animals↗
PubMed2001

[Detection of beat-to-beat changes in high frequency components of the QRS complex using a free optimal signal averaging system: relationship with ventricular arrhythmias].

In this study, we evaluated the relationship between beat-to-beat changes in high frequency components of the QRS complex and ventricular arrhythmias by using a newly developed event-related (ER) signal averaging technique. The study involved 82 patients with premature ventricular contractions (PVC), 56 of whom, including 16 with ventricular tachycardia (VT), were enrolled in Analysis I. In Analysis I, averaged sinus beats were classified into three patterns: 1) the sinus beat immediately before PVC (BEF); 2) that immediately after PVC (AFT); and 3) all sinus beats (ALL). Analysis II covered the remaining 26 patients, and involved five modes of event-related signal averaging, using: 1) the second beat preceding PVC (2-B); 2) the beat immediately preceding PVC (1-B); 3) the beat immediately after PVC (1-A); 4) the second beat after PVC (2-A); and 5) the beat isolated (ISO) from PVC. The filtered QRS duration (F-QRS) and the integral voltage of the terminal 40 msec (RMS 40-I) were measured using these averaging patterns. F-QRS in the VT group was longer than that in the non-VT group, but RMS 40-I was shorter. The F-QRS of BEF (1-B) was significantly longer than that of AFT (1-A). The transient difference in the F-QRS was observed in both VT and non-VT groups. This difference was almost eliminated at AFT (1-A) in the non-VT group, but was stable at AFT (1-A) in the VT group. Simultaneousely, RMS 40-I in BEF was significantly shorter than that in AFT. This transient decrease of RMS 40-I was observed in both VT and non-VT groups. Although RMS 40-I after this decrease showed a return almost to the control level at AFT in the non-VT group, it tended to remain even at AFT in the VT group. The sudden prolongation of F-QRS that occurred with the RMS 40-I decrease in BEF was related to the appearance of PVCs. We attributed the fact that these changes in F-QRS and RMS 40-I were observed even at AFT in the VT group to electrophysiologically preferable conditions for reentry.

Electrocardiography↗
PubMed2001

Clinical and pathological significance of vitamin D receptor gene polymorphism for prostate cancer which is associated with a higher mortality in Japanese.

The purpose of this study was to investigate the TaqI vitamin D receptor (VDR) polymorphism in both Japanese prostate cancer patients and Japanese noncancer controls in order to determine if an association exists between VDR genotype with clinical and pathological risk of prostate cancer patients. This study involved 115 patients with prostate cancer and 133 male age-matched noncancer controls genotyped for a previously described TaqI restriction fragment length polymorphism (RFLP) at codon 352 in exon 9 of the VDR gene. Products were digested into T allele or t allele according to the absence or presence of TaqI restriction site with individuals being classified as TT, Tt, or tt. The genotype tt was higher among the control group (6.0%) compared to the patients with prostate cancer (1.8%), but not so (OR=0.28; 95%o CI, 0.06-1.33; p=0.081). In addition, the genotype TT was statistically higher among patients with locally advanced or metastatic disease (T3/T4/NI/M1) compared to controls (OR=2.52; 95%o CI, 1.21-5.27; p=0.009). Lastly, the genotype TT was statistically higher among patients with poorly differentiated adenocarcinoma compared to controls (OR=5.38; 95%o CI, 1.57-18.50; p=0.002). These data demonstrate that VDR genotype plays an important role in determining the risk of more clinically advanced and pathologically aggressive prostate cancer which is associated with a higher mortality rate in Japanese men.

Aged↗
PubMed2001

Plasma natriuretic peptide levels and daily physical activity in patients with pacemaker implantation.

To determine whether plasma ANP and/or BNP levels can be used to detect limitations in daily physical activity after pacemaker implantation, we measured plasma ANP and BNP levels at a pacemaker follow-up clinic in 56 patients (62+/-15 yrs, 2AAI, 9VVI, 34DDD, 7VDD and 4 rate-responsive modes), daily physical activity evaluated by a specific activity scale questionnaire (METs) and VO2 max obtained by expired gas analysis during ergometer exercise. A very close correlation (n=6, r=0.89, p<0.05) was obseved between. ANP in patients with daily physical activity class III (2-4 METs, n=21) was significantly higher than class II (5-6 METs, n=23, p<0.01) and class I (>7 METs, n=8, p<0.01), while BNP in class III patients was significantly higher than in class II (p<0.0001) and class I (p<0.0001) patients. Significant correlations between daily physical activity and BNP (r=-0.64, p<0.0001) and ANP (r=-0.43, p<0.001) were observed. Physiological pacing mode did not necessarily offer a better profile for BNP levels compared with non-physiological pacing modes. Patients with ventricular pacing (wide QRS: VDD, RR-VVI and VVI) showed significantly high ANP (p<0.01) and BNP (p<0.01) levels compared with those in patients with atrial pacing (narrow QRS: AAI and RR-AAI). During exercise, plasma catecholamines and ANP levels were significantly elevated, however, BNP levels, which were already elevated at rest, did not change significantly, and reflected a limitation of daily physical activity. The present study revealed that 37.5% of the patients displayed an elevation in BNP and this was judged to be a limitation of physical activity class III being equivalent to NYHA II or more. Elevated resting BNP levels reflected a limitation in daily physical activity in these patients. These findings suggested a third condition for physiological pacing--synchronization of ventricular contraction (narrow QRS pacing)--in addition to the two conventional conditions of atrioventricular synchrony and rate-responsiveness.

Aged↗
PubMed2001

Renal tubular dysfunction in male inhabitants of a cadmium-polluted area in Toyama, Japan--an eleven-year follow-up study.

An eleven-year follow-up study was carried out to elucidate the changes in the level of environmental exposure to cadmium (Cd) from rice after soil replacement of polluted paddy fields and these effects on urinary excretion of Cd in male inhabitants of a Cd-polluted area in Toyama, Japan. In addition, the prevalence of renal tubular dysfunction (RTD) was examined to clarify the progress of Cd-induced RTD. One hundred and twenty-seven male inhabitants born between 1914 and 1929 in 11 districts of the Cd-polluted Jinzu River basin and 31 reference subjects in 2 adjacent districts were examined twice in 1985-86 and 1996-97. The geometric means of Cd concentrations in polished rice (Cd-R) in the Cd-polluted areas were 0.18 ppm in 1985 and 0.21 ppm in 1986; these values were significantly higher than those of the reference areas (0.13 ppm in 1985 and 0.12 ppm in 1986). After 11 years, the Cd-R levels were significantly decreased to approximately half (0.08 ppm in 1996, 0.12 ppm in 1997) due to soil replacement of polluted paddy fields, which has been carried out since 1980. The mean Cd levels in urine (Cd-U) were significantly reduced from 7.9 and 9.5 microg/g creatinine in the initial study to 6.9 and 6.8 microg/g creatinine in the follow-up study. However, the prevalence of RTD, which was determined by urinary beta2-microglobulin exceeding 1 mg/g creatinine and urinary glucose exceeding 150 mg/g creatinine, increased from 18 and 23% in the 1985-86 study to 25 and 32% in the 1996-97 study, and a total of 12 new cases (12%) of RTD were found. Whereas, only one subject (4%) in the reference control areas was identified as RTD. Cd-induced RTD was prevalent, progressive and irreversible for male inhabitants of the Cd-polluted Jinzu River basin, although the environmental exposure to Cd through rice was significantly reduced by soil replacement of polluted paddy fields.

Aged↗
PubMed2001

[Epidemiological investigation of tinea pedis in groups of healthy students, research workers and females wearing boots].

The infection rate, causative dermatophytes, and dermatophyte dissemination of tinea pedis in young healthy Japanese were studied by direct microscopic examination, slant cultures, and foot-press culture method. Questionnaires on subjective symptoms and treatments were also distributed. Among fifty-eight medical students with a mean age of 23.9 years, thirteen (22.4%) showed positive by direct microscopic examination and T. mentagrophytes was more dominant than T. rubrum by slant cultures. In one hundred and sixteen student feet, twelve were infected and disseminating dermatophytes, four were infected but not disseminating, three were not infected but adhering dermatophytes. The infection rate of tinea pedis was thus 24.1%. Among thirty-seven research workers (mean age: 34.8), twenty-one (56.8%) showed positive by direct microscopic examination. All the dermatophytes isolated by slant cultures were T. mentagrophytes. In seventy-four feet, twenty-nine were infected and disseminating, ten were infected but not disseminating, and three were adhering dermatophytes. The infection rate was 64.9%. Among thirty-one females wearing boots (mean age: 21.0), seven (22.6%) were infected and T. mentagrophytes was more dominant. In sixty-two feet, eight were infected and disseminating, one was infected but not disseminating, and five were adhering dermatophytes. The infection rate of tinea pedis was quite high and T.r/T.m rate was low in the three groups. Most of the patients had had no treatment and were disseminating dermatophytes.

Adult↗
PubMed2001

[The efficacy and safety of terazosin and tamsulosin in patients with urinary disturbance accompanying prostatic hypertrophy].

Terazosin (TE) and tamsulosin (TA) were allocated randomly to 38 patients who had urinary disturbance accompanying prostatic hypertrophy, and the efficacy and safety of the drugs were examined. Subjective symptoms due to I-PSS were improved significantly in both TE and TA groups. On the other hand, objective symptoms such as the maximum urinary flow and mean urinary flow were improved more in the TE group. TE showed hypotensive and cholesterol-decreasing effects in patients who also had hypertension and hyperlipemia. No unknown adverse reactions were observed in either groups, and the drugs were shown to be highly safe. TE was considered to be useful as the first choice drug for the patients with hypertension and or hyperlipemia and those with severe objective symptoms. TA was considered to be useful for the patients with impaired drug compliance or those with severe subjective symptoms though objective symptoms were not so severe.

Adrenergic alpha-Antagonists↗
PubMed2001

Individual differences in urinary cotinine levels in Japanese smokers: relation to genetic polymorphism of drug-metabolizing enzymes.

Urinary cotinine, one of the main metabolites of nicotine, has been widely used as a biomarker for assessment of direct or passive exposure to cigarette smoke. However, there is wide variation of the cotinine level among smokers who smoke the same number of cigarettes. To use urinary cotinine as a proper exposure-biomarker for cigarette smoke, interindividual variations of cotinine formation must be considered. Therefore, we studied the effects of genetic polymorphisms in drug metabolic enzymes on urinary cotinine levels among 190 male Japanese smokers (ages 19-66 years; mean, 40.6 years). Genetic polymorphisms in cytochrome P-450s (CYP1A1, CYP2A6, CYP2E1), and aldehyde dehydrogenase 2 (ALDH2) were determined by analyzing DNA isolated from peripheral blood. Cotinine in morning spot urine was analyzed by high-performance liquid chromatography. Lifestyle, i.e., smoking, alcohol consumption, and intake of coffee or tea, was examined using a questionnaire. The number of cigarettes smoked and CYP2A6 polymorphism were significantly associated with the urinary cotinine level. Especially, the urinary cotinine levels was drastically lower in CYP2A6-deleted homozygous (CYP2A6*4/*4) subjects than in CYP2A6*1 allele-positive subjects. The polymorphism in the CYP2E1 5'-flanking region was related to the urinary cotinine level in intermediate smokers (who smoke 11-20 cigarettes/day; P < 0.01). Polymorphisms in CYP1A1 or ALDH2, and consumption of alcohol, coffee, or tea were not associated with the urinary cotinine level.

Adult↗
PubMed2001

Population pharmacokinetics, protein binding and antiarrhythmic effects of disopyramide enantiomers in arrhythmic patients.

Disopyramide (DP) is widely used as an antiarrhythmic agent. The antiarrhythmic effects of its enantiomers differ from each other and its metabolism and protein binding are also stereoselective. Population pharmacokinetic parameters of DP racemate, enantiomers (S(+)-DP, R(-)-DP), and their unbound concentrations (uDP, S(+)-uDP and R(-)-uDP) were analyzed using the nonlinear mixed effect model (NONMEM) program. Data were available from 108 points of 33 arrhythmic patients on maintenance therapy with DP racemate. We evaluated the factors to which pharmacokinetic parameters are attributed and the relationships between each serum concentration and the antiarrhythmic effect. A one-compartment model was fitted to the data using NONMEM. For DP, S(+)-DP and R(-)-DP, elimination rate constants (kes) were estimated as 0.0648, 0.0663 and 0.0691/h, respectively and the mean apparent volume of distribution (Vd/F) were estimated as 63.2, 54.1 and 71.6 l, respectively. Using the ke and Vd/F values estimated by NONMEM, time-concentration curves were well fitted to the observed data. Unbound fractions of both DP enantiomers showed nonlinearity and the binding ratio of S(+)-DP was 0.84 +/- 0.07, which was higher than that of R(-)-DP [0.70 +/- 0.11 (p < 0.01)]. Unbound fractions of both DP enantiomers correlated with alpha1-acid glycoprotein (AGP) (p < 0.01). On the other hand, using NONMEM, a significant proportion of the variability of Vd/F could be attributed only to AGP (p < 0.001). NONMEM was able to clarify the pharmacokinetic features in the protein binding of DP. Individual steady state concentrations were estimated by NONMEM using the Bayesian method. The average unbound concentrations of all nine responders were higher than those of the four non-responders, even though this difference was not significant. Unbound concentrations may reflect drug concentrations in the tissue, which suggests that these concentrations may indicate an antiarrhythmic effect rather than the total concentration.

Adolescent↗
PubMed2000

Hinokitiol, a selective inhibitor of the platelet-type isozyme of arachidonate 12-lipoxygenase.

Hinokitiol (4-isopropyltropolone), a constituent of Japanese cypress, reversibly inhibited platelet-type 12-lipoxygenase with an IC(50) of 0.1 microM, and the enzyme activity was almost lost at 1 microM. The compound was much less active with other lipoxygenase enzymes with higher IC(50) values (leukocyte-type 12-lipoxygenase, 50 microM; soybean lipoxygenase, 17 microM; 15-lipoxygenase-1, >100 microM; 5-lipoxygenase, 17 microM). Hinokitiol up to 100 microM had almost no effect on cyclooxygenases-1 and -2. Their structure-activity relationship examined with various tropolone derivatives indicated the requirements of the 2-hydroxyl group and 4-alkyl group for the potent and selective inhibition of platelet-type 12-lipoxygenase.

Animals↗
PubMed2000

Neurological accidents caused by repetitive breath-hold dives: two case reports.

We report two Japanese male professional breath-hold divers (33 and 39 years of age) who experienced neurological disorders during repetitive dives to over 20 m of seawater. One patient had right homonymous hemianopsia, and the other presented with right hemiparesis with facial involvement and sensory deficit. In addition, they each had a history of neurological problems following such dives. Magnetic resonance images of their brains disclosed multiple T2-weighted hyperintensities corresponding to their neurological symptoms. Their brain lesions suggest a multiple cerebral infarction caused by occlusion of the cerebral arteries. We conclude that the repetitive deep breath-hold dives induced the brain involvement.

Adult↗
PubMed2000

Structural analysis of Arabidopsis thaliana chromosome 3. II. Sequence features of the 4,251,695 bp regions covered by 90 P1, TAC and BAC clones.

To deduce the entire sequence of the top arm of the Arabidopsis thaliana chromosome 3, the sequence determination was performed on a total of 90 P1, TAC and BAC clones chosen according to our sequencing strategy. Sequence features of the resulting 4,251,695 bp regions were analyzed with various computer programs for similarity search and gene modeling. As a result, a total of 941 potential protein-coding genes were identified. The average density of the genes identified was 1 gene per 4210 bp. Introns were observed in 73% of the genes, and the average number per gene and the average length of the introns were 3.6 and 159 bp, respectively. These sequence features are essentially identical to those of chromosomes 3 and 5 in our previous reports. The regions also contained 14 tRNA genes when searched by similarity to reported tRNA genes and the tRNA scan-SE program. The sequence data and information on the potential genes are available through the World Wide Web database KAOS (Kazusa Arabidopsis data Opening Site) at http://www.kazusa.or.jp/kaos/.

Arabidopsis↗
PubMed2000

Magnetic order in the heavy fermion compound CeCu6 at mK temperatures

We have measured the ac magnetic susceptibility in various fields and thermal expansion of single crystals of the heavy fermion compound CeCu6 at temperatures down to 250 &mgr;K. The susceptibility of CeCu6 shows a peak at about 2 mK and has a large anisotropy. We also detected an anomaly of thermal expansion at the same temperature. The observed behaviors of the susceptibility and the thermal expansion in CeCu6 indicate the occurrence of an antiferromagnetic order.

Journal Article↗