Biomedical subjects

T Katoh

Publications and source records attributed to T Katoh.

At least 163 records · Page 9Linked to original sources

PubMed1999

[Is left ventricular regional wall motion after CABG influenced by cardioplegic protection?].

This clinical study was conducted to determine whether different techniques of cardioplegic protection reflected left ventricular regional wall motion after CABG. A total of 43 patients with more than 90% stenosis of the LAD (seg 6 and/or 7) before CABG, who had patent grafts were allocated to two groups: namely, the crystalloid group, comprised of 23 patients given cold crystalloid cardioplegia and topical ice slush, and the blood group, comprised of 20 patients given tepid blood cardioplegia delivered intermittently antegrade. Each group was divided into two subgroups according to whether the left ventricular regional wall motion showed no change or deterioration after CABG. We also examined the relationship between the grading of the collateral artery before CABG and the postoperative ventricular regional wall motion. The number of patients who showed deterioration after CABG was higher in the crystalloid group than in the blood group (p = 0.008). Moreover, patients in the crystalloid group whose collateral artery had been graded as 0 before CABG tended to show deterioration of left ventricular local wall motion after CABG (p = 0.07). Whereas those patients in the blood group did not. In conclusion, the incidence of deterioration after CABG was higher in the crystalloid group than in the blood group.

Aged↗

PubMed1999

[Dynamic generation of diagnostic knowledge from a database of well defined case clinical records].

To promote an evidence-based practice of laboratory medicine, we created a database of 1584 typical case records consisting of 30 common diseases. Cases without therapy or major complication were carefully selected. Characteristic clinical symptoms and signs indicating the severity were recorded together with general laboratory test results. A user-friendly computer system for interpretive laboratory diagnosis was also created. It features (1) automatic graphics for visualizing distributions of laboratory values and/or prevalence of clinical symptoms and signs, (2) simultaneous display of distributions of common test values for any combination of diseases, (3) quick subclassification of cases within a disease group by any clinical characteristic, (4) diagnostic guidance by dynamic calculation of a novel similarity index that represents matching of a given set of signs/values with those of typical cases in the database.

Clinical Laboratory Techniques↗

PubMed1999

[p-Nitrophenol].

Explore the source record for details and available documents.

Environmental Monitoring↗

PubMed1998

A novel inhibitory effect on prostacyclin synthesis of coupling factor 6 extracted from the heart of spontaneously hypertensive rats.

The possible presence of an unknown prostacyclin synthesis inhibitory substance has been reported in some strains of rats. We purified the inhibitory substance from the heart of spontaneously hypertensive rats by collecting active fractions after gel-filtration column chromatography and two steps of reverse-phase high performance liquid chromatography. The amino acid composition and automated gas-phase sequencing of the full-length substance and fragments cleaved by AspN indicated that the prostacyclin-inhibitory peptide was identical to coupling factor 6. Recombinant rat coupling factor 6, which was synthesized using a cleavable fusion protein strategy, attenuated base-line and bradykinin (10(-6) M)-induced prostacyclin synthesis and [3H]arachidonic acid (AA) release in human umbilical vein endothelial cells in a dose-dependent manner (10(-9)-10(-7) M). Exogenous AA- and prostaglandin H2-induced prostacyclin synthesis were unchanged even after treatment with 10(-7) M recombinant coupling factor 6. Base-line and bradykinin-induced [3H]AA release were suppressed by arachidonyltrifluoromethyl ketone, a relatively specific inhibitor of cytosolic phospholipase A2 at 40 microM, and simultaneous administration of coupling factor 6 showed no further effect. Neither oleyloxyethyl phosphorylcholine at 1 microM nor bromoenol lactone at 1 microM affected AA release. Preincubation (1 min) with 10(-7) M recombinant coupling factor 6 had no influence on adenosine diphosphate- and collagen-induced platelet aggregations. We conclude that coupling factor 6 possesses a novel function of prostacyclin synthesis inhibition in endothelial cells via suppression of Ca2+-dependent cytosolic phospholipase A2, although it is unclear whether coupling factor 6 functions in normal conditions or only in pathophysiological states.

Adenosine Triphosphatases↗

PubMed1998

Effects of glutathione S-transferase (GST) M1 and GSTT1 genotypes on urothelial cancer risk.

The M1 member of the mu class of the glutathione S-transferase (GSTM1) gene is present in about 50% of individuals. GSTT1, a member of the theta class, which has been recently shown to be polymorphic, is expressed in 35-90% of individuals. In this study, 145 Japanese patients with urothelial transitional cell carcinoma and 145 healthy controls, frequency-matched for age and gender, were compared for frequencies of GSTM1 and GSTT1 genotypes. The urothelial cancer risk increased due to the GSTM1 null genotype (odds ratio (OR) 1.71, 95% confidence interval (CI) 1.05-2.79). On the other hand, the OR tended to decrease due to the GSTT1 null genotype, although not significantly. Among individuals of the GSTM1 null genotype, those of the GSTT1-positive genotype had a two-fold risk (OR 2.62, 95% CI 1.36-5.05) compared with the GSTT1 null genotype (OR 1.25, 95% CI 0.62-2.51). A significant interaction between the GSTM1 genotype and smoking status was found; the GSTM1 null genotype was associated with an increased risk of urothelial cancer among smokers (OR 1.98, 95% CI 1.10-3.57).

Aged↗

PubMed1998

PCR on cerebrospinal fluid to show influenza-associated acute encephalopathy or encephalitis.

BACKGROUND: Except for Reye's syndrome, influenza-associated acute encephalopathy or encephalitis is not universally recognised. We did a multicentre study of laboratory and clinical data for patients with influenza-associated acute encephalopathy or encephalitis. METHODS: In Nagoya, Japan, ten patients with acute encephalopathy or encephalitis associated with influenza-like illness were admitted to our hospitals between April, 1996, and March, 1997. We collected clinical, laboratory and serological data and assessed cerebrospinal fluid samples by PCR for influenza A and B. FINDINGS: Seven patients, aged 22 months to 4 years, had evidence of recent influenza infection, six with type-A/Hong Kong (H3N2) and one with type B. The first sign in the central nervous system appeared within 2 days of fever in all but one patient. The first sign of involvement of the central nervous system was generalised convulsions in all patients. Two patients died, one had sequelae, and four survived without sequelae. PCR for influenza type A was positive for five patients. INTERPRETATION: The results of PCR suggest that at least part of the influenza type A genome existed in the central nervous system. Influenza-associated acute encephalopathy or encephalitis in young children deserves wider recognition.

Acute Disease↗

PubMed1998

Skeletal muscle myosin monomer in equilibrium with filaments forms a folded conformation.

Rabbit skeletal myosin forms stable filaments under physiological conditions, and only a small amount stays as a monomer in equilibrium with filaments. The myosin monomers were observed in two conformational states, as extended and folded forms upon electron microscopy and gel filtration high performance liquid chromatography. The fraction of monomers in the folded conformation increased with a decrease in the concentration of NaCl below 0.2 M, and the conformational state was affected neither by the presence of ATP nor by the phosphorylation of regulatory light chain. In most of the folded monomers, the tail bent back toward the heads at one region, 45 nm apart from the head-tail junction, and the remaining tail portion containing the C-terminal tip appeared to interact with the head-tail junction. Only a small percentage of the folded monomers was in a more compact conformation close to the 10 S conformation of vertebrate smooth muscle and non-muscle myosins. The folded monomers, however, may not trap the products of ATP hydrolysis as assessed by single turnover experiments. The percentage of monomers in the 10 S-like conformation was increased by the exchange of a regulatory light chain with the smooth muscle light chain, indicating the participation of head-tail junction, including the regulatory light chain in the formation of folded conformation. The folded conformation may be common to various myosin IIs, suggestive of common roles for the folded monomers.

Animals↗

PubMed1998

Synchrotron radiation direct photo-etching of polymers and crystals for micromachining.

Synchrotron radiation etching of polymers and optical crystals which are transparent throughout the spectral range from visible to ultraviolet has been carried out without using any chemicals, successfully creating high-aspect-ratio microstructures for micromachining. A detailed study of the etching rates by varying the synchrotron beam current, sample temperature, beam size and aspect ratio showed that this synchrotron radiation process is essentially different from laser ablation, while an in situ mass spectrometric analysis of gaseous etching products showed that the dissociation mechanism involved with the synchrotron radiation processing, even with heating, is completely different from the thermal dissociation of the laser ablation.

Journal Article↗

PubMed1998

The response of blood flow between the internal thoracic and ileocecal arteries to inotropic agents in a canine model.

The pharmacologic response of coronary artery bypass conduits is of great importance. This study was designed to clarify the response of blood flow between the internal thoracic artery (ITA) and the ileocecal artery (ICA) to inotropic agents. The responses of the ITA and ICA to epinephrine, dopamine, isoproterenol, and dobutamine were examined by collecting free-flowing blood from a canine model. There were no significant differences in the response to inotropic agents between the ITA and the ICA. Epinephrine and dopamine increased the graft flow, whereas isoproterenol and dobutamine decreased the graft flow percentages of the cardiac output. These results suggest that the flow response to inotropic agents is equivalent in canine ITA and ICA grafts.

Animals↗

PubMed1998

Recovery after prolonged cross-clamping tepid blood cardioplegia: report of a case.

Despite a prolonged repetitive aortic cross-clamp time of 411 min, a patient who suffered a left ventricular rupture after undergoing mitral valve replacement following mitral valvuloplasty and Maze procedure recovered without any permanent residual left ventricular dysfunction. During the aortic cross-clamping we used tepid blood cardioplegia for myocardial protection. This case report serves to demonstrate the potential of tepid blood cardioplegia as an effective method of myocardial protection.

Aged↗

PubMed1998

[Experimental study of coronary artery anastomosis using VCS clips].

The experiment was intended to test the feasibility of VCS clips for coronary anastomosis during minimally invasive direct coronary artery bypass grafting (MIDCAB). Six dogs were anesthetized under endotracheal intubation and were placed on right lateral position. Three 10.5-mm ports were placed on the left lateral chest wall (3rd, 5th and 7th intercostal space) and the left internal thoracic artery (LITA) was dissected completely from its root to bifurcation under thoracoscope. Chest was opened through the left 6th intercostal space. The anastomotic site of LAD was dissected and was then occluded temporally for 5 minutes to obtain ischemic preconditioning. The anastomosis was performed by the following procedure; horizontal mattress sutures of 8-0 polypropylene were placed on heel, toe and the center of both lateral sides. Two VCS clips (8 in total), 0.9-mm in size, were applied between every two sutures. After the measurement of graft flow, the pedicle was transected and an angiography was done. Graft flow was 12-17 ml/min (mean 14.7 +/- 2.1 ml/min) and cineangiogram showed good patency of LITA and no anastomotic stenosis. VCS clips were supposed to have a potential for facilitating port access coronary artery bypass grafting.

Anastomosis, Surgical↗

PubMed1998

Arterial reconstruction: justified for patients with intermittent claudication?

The objective of this study was to evaluate the effects of arterial reconstruction in patients with intermittent claudication. A total of 243 patients (305 limbs) underwent lower extremity vascular reconstruction at our institution from 1979 to 1995. They were assessed by physical examination, pulse volume recordings, segmental pressure, Duplex ultrasonography, and intravenous subtraction arteriography to evaluate the effects of arterial reconstruction. Surviving patients (220 limbs) were enrolled for evaluation of outcome during the follow-up period. There were 59 deaths during the follow-up period. The cumulative life-table 5-year patency rates were 90% +/- 3%, 73% +/- 6%, and 74% +/- 10% for aortoiliac, infrainguinal, and aortofemorodistal arterial reconstructions, respectively. Among 129 repairs in the aortoiliac region, Fontaine stages I, II, and III were found in 109 limbs (84.5%), 17 limbs (13.2%), and 2 limbs (1.5%), respectively. There was one (0.7%) minor amputation. There was Fontaine stage I in 50 limbs (76.9%), Fontaine stage II in 14 limbs (21.5%), and Fontaine stage III in 1 limb (1.5%) for repairs in the infrainguinal region. Among the 26 aortofemorodistal repairs, there was Fontaine stage I in 21 limbs (81%) and Fontaine stage II in 5 limbs (19%). There was a statistically significantly higher incidence of Fontaine stage I than Fontaine stage II or III in aortofemoral, infrainguinal, and aortofemorodistal arterial reconstructions (p < 0.0001). Arterial reconstruction for patients at Fontaine stage II offered benefits and improved quality of life at follow-up. Arterial reconstruction for patients at Fontaine stage II offers benefits and improved quality of life at follow-up. It was concluded that the significant improvement in quality of life after arterial reconstruction warrants continued use of the procedure in patients with intermittent claudication.

Adult↗

PubMed1998

Increased serum interleukin-8: correlation with poor prognosis in patients with postoperative multiple organ failure.

This study investigated whether cytokines and colony-stimulating factors can predict prognosis in patients with postoperative multiple organ failure (MOF). We evaluated 14 patients with postoperative MOF who underwent operation for cardiovascular disease. Seven patients recovered from MOF (survivors) and seven did not recover and died (nonsurvivors). The white blood cell (WBC) count, granulocyte colony-stimulating factor, monocytic colony-stimulating factor, interleukin-6 (IL-6), and IL-8 were measured on the day the patients were judged to be in MOF and each week thereafter until the patients recovered or died. Survivors and nonsurvivors were equivalent in terms of age, gender, proportion of use of extracorporeal circulation, operation time, volume of blood transfusion, time from operation to the onset of MOF, the MOF score, proportion of bacteremia, duration of MOF, and number of failed organs. The mean duration of MOF was less than 2 weeks in both groups; therefore the measurements were compared on the first day of MOF and 1 week later. No significant differences between the two groups in terms of WBC counts, colony-stimulating factors, and IL-6 levels were noted. However, the serum level of IL-8 was significantly higher in nonsurvivors than in survivors. Patients with a high serum levels of IL-8 at the time of MOF had a poor prognosis.

Aged↗

PubMed1998

Subretinal administration of tissue-type plasminogen activator to speed the drainage of subretinal hemorrhage.

BACKGROUND: Bleeding into the subretinal space in the vicinity of the macula is associated with age-related macular degeneration or retinal arterial macroaneurysm. The prognosis for restoration of vision is poor in the presence of blood clots. METHODS: Using a simple device composed of three disposable syringes we injected tissue-type plasminogen activator (tPA) into the subretinal space during conventional vitrectomy in six patients to assist the draining of subretinal clots. RESULTS: Four of six patients recovered their visual acuity postoperatively, while visual acuity in the other patients was stabilized. CONCLUSION: Early drainage of subretinal hemorrhage assisted by the introduction of tPA into the subretinal space led to uncomplicated surgery and favorable postoperative results.

Aged↗

PubMed1998

Granulocyte elastase release and pulmonary hemodynamics in patients with atrial septal defect.

BACKGROUND: In patients with increased pulmonary artery pressure, the pulmonary vascular endothelium is morphologically and functionally abnormal and may be vulnerable to neutrophil-mediated injury induced by cardiopulmonary bypass (CPB). We investigated the relation between levels of granulocyte elastase (GEL), interleukin-6, or interleukin-8 after CPB and preoperative pulmonary hemodynamics or changes in pulmonary function after the operation. METHODS: We measured plasma levels of GEL, interleukin-6, and interleukin-8 before and after CPB in patients who underwent closure of an atrial septal defect. Preoperative and postoperative respiratory index were evaluated. Preoperative pulmonary hemodynamics were determined within 1 month before the operation. RESULTS: The level of GEL rose significantly after CPB from baseline (164.8 +/- 81.3 versus 819.4 +/- 320.3 microg/L; p < 0.01). Levels of interleukin-6 and interleukin-8 showed no significant changes after CPB. Peak level of GEL was significantly correlated with preoperative systolic pulmonary artery pressure (r = 0.76; p = 0.017), mean pulmonary artery pressure (r = 0.75; p = 0.021) and pulmonary-to-systemic arterial pressure ratio (r = 0.77; p = 0.016), but not with the hemodynamic variables for pulmonary blood flow or pulmonary resistance. Moreover, the value of (postoperative respiratory index - preoperative respiratory index)/preoperative respiratory index was positively correlated with the peak level of GEL (r = 0.72; p = 0.030). CONCLUSIONS: The increase in GEL level after CPB is proportional to the increase in preoperative pulmonary artery pressure, which may cause the accordant pulmonary vascular damage.

Adult↗

PubMed1998

Wavelet transform system makes one-beat analysis possible in late potential evaluation.

High-frequency components of the QRS complex, including late potentials, can be analyzed by signal averaging (SA). However, this method may fail to detect transient changes as a result of cancellation. The wavelet transform, which has a superior time-frequency resolution, was used to analyze beat-to-beat changes of the QRS components in 50 normal subjects and 50 patients who showed positive late potentials. The transformed data, displayed in three dimensions and in color, were highly reproducible in each patient. Measurement of high-power duration at a frequency of 50 Hz (WD50) showed a significant correlation between WD50 and filtered QRS duration in both groups. When the mean +/- SD of WD50 in normal subjects was defined as normal, 96% of patients with late potentials were out of the normal range. The wavelet signals in patients with late potentials were more inhomogeneous than those of normal subjects. It is concluded that this newly developed color display, three-dimensional wavelet transform system showed extremely good time-frequency resolution in analyzing every beat without signal averaging.

Action Potentials↗

PubMed1998

Mechanism of atrial escape-capture bigeminy: second-degree sinoatrial exit and entrance block.

Two women with atrial escape-capture bigeminy were reported in whom sinus P waves and escape P waves alternated with each other. Their electrocardiographic findings showed that, during the bigeminal rhythm, 2:1 exit block of sinus impulses associated with entrance block of escape impulses occurred in the sinoatrial junction. Three phenomena are suggested to explain the observations. (1) Seeming bradycardia-dependent sinoatrial exit block may have occurred, probably as a result of phasic changes in vagal tone due to respiration, with decreased vagal tone depressing conductivity in the sinoatrial junction to a greater degree than automaticity in the sinus node. (2) In case 1, type II second-degree entrance block in the sinoatrial junction may have occurred, reflecting the presence of sinus parasystole with incomplete entrance block. (3) Sinus escape also may have occurred, especially in case 2. These phenomena have never been reported before.

Aged↗

PubMed1998

Apparent bradycardia-dependent block in the accessory pathway in intermittent Wolff-Parkinson-White syndrome.

A case of intermittent Wolff-Parkinson-White syndrome is reported, which is the first report of an apparent bradycardia-dependent block in the accessory pathway. When the P-P interval gradually lengthened to a critical value of 0.89 second or more, preexcitation failed to occur, but thereafter, when the P-P interval gradually shortened to 0.89 second or less, preexcitation again occurred. These findings seem to suggest that bradycardia-dependent block occurred in the accessory pathway. In the electrocardiogram taken on another day, however, when a ventricular extrasystole was followed by a compensatory pause, the ensuing QRS complex showed preexcitation, although the pause was markedly longer than the critical period of 0.89 second. This indicates that this case is not one of true bradycardia-dependent block in the accessory pathway. Rather, the effect occurred because increased vagal tone depressed conductivity in the accessory pathway to a greater degree than automaticity in the sinus node.

Arrhythmia, Sinus↗