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Biomedical subjects

T Katoh

Publications and source records attributed to T Katoh.

At least 127 records · Page 7Linked to original sources
PubMed1999

Prediction of graft prolongation by mixed lymphocyte culture following anti-CD4 monoclonal antibody treatment among different donor-recipient combinations.

This study was conducted to examine whether mixed lymphocyte culture (MLC) could be used as a predictor of the efficacy of anti-CD4 monoclonal antibody (MAb) immunosuppression in vivo in a mouse model. C57BL/10 or BALB/c hearts were transplanted into C3H.He recipients. Anti-CD4 MAb administration prolonged graft survival, but there was a clear difference between the two donor-recipient combinations studied, the median survival time (MST) being >100 days in the C57BL/10 --> C3H group, and 17 days in the BALB/c --> C3H group. Anti-CD8 MAb prolonged the survival of C57BL/10 hearts slightly to a MST of 22 days, but the BALB/c hearts were rejected at control rates. Combining anti-CD4 and anti-CD8 antibody therapy prolonged the survival of C57BL/10 hearts indefinitely, but had little effect on the survival of BALB/c grafts, achieving an MST of only 24 days. Next, MLCs were performed in the presence and absence of the MAbs and compared with the graft survival data. The inhibition rates in the MLC, being the C3H lymph node cell responder, correlated well with graft survival. When three kinds of C3H responder cells, namely lymph node (LN) cells, T cells, and CD4+ cells, were examined to determine which was the most suitable for predicting graft survival, the MLC results showed that the responses of LN cells correlated most closely with graft outcome. In conclusion, MLC using LN cells as the responder is a useful tool for predicting allograft survival induced by anti-CD4 MAb therapy.

Animals↗
PubMed1999

An ascending aortic aneurysm caused by giant cell arteritis: report of a case.

A 69-year-old woman was referred to our hospital for investigation of an abnormality detected by a chest roentgenogram, and was subsequently found to have an ascending aortic aneurysm. She had not suffered any symptoms such as headache or polymyalgia rheumatica. Aneurysmectomy and reconstruction of the ascending aorta was performed using cardiopulmonary bypass, and pathological examination of the aneurysmal wall revealed giant cell arteritis (GCA). Preoperatively, she had not suffered any temporal pain, and no signs of inflammation were detected serologically. GCA is a rare cause of aortic aneurysm in the Japanese population, and a brief review of the literature on this unusual entity is presented following this case report.

Aged↗
PubMed1999

Coronary bypass surgery after renal transplantation.

We report, herein, cases of two renal transplantation patients who underwent coronary artery bypass grafting and discuss the perioperative management of this clinical situation. The first case was a 43-year-old male who underwent coronary artery bypass grafting 50 days after renal transplantation, and the second was a chronic case of a 49-year-old male who underwent coronary artery bypass grafting 17 years after renal transplantation. Prior to the operation, the first patient was continuously administered 2 mg/kg/day of cyclosporin A with the dosage regulated according to the plasma level. The second patient was administered 50 mg/day of cyclophosphamide intravenously instead of an oral dosage of 50 mg/day of azathioprine just prior to the operation. In both patients, perfusion pressure during cardiopulmonary bypass was maintained at approximately 80 mmHg in order to obtain optimal urine output. The CD4/CD8 ratio was monitored for indication of graft rejection, but no remarkable changes were observed perioperatively in either patient. Both patients followed a good clinical course and their postoperative renal function was well maintained. The urine output during cardiopulmonary bypass was 300 ml and 650 ml, respectively. The patients were discharged 15 and 27 days after their operation, respectively. In conclusion, coronary artery bypass grafting can be safely performed in patients who have undergone renal transplantation, if there is appropriate perioperative usage of immunosuppressive agents and maintenance of perfusion pressure during cardiopulmonary bypass.

Adult↗
PubMed1999

Long-term treatment with antipsychotic drugs in conventional doses prolonged QTc dispersion, but did not increase ventricular tachyarrhythmias in patients with schizophrenia in the absence of cardiac disease.

OBJECTIVE: The aim of this study was to examine the hypothesis that long-term treatment with antipsychotic drugs in conventional doses prolongs QTc dispersion and increases ventricular tachyarrhythmias in patients with schizophrenia in the absence of cardiac disease. METHODS: We measured QTc and QTc dispersion and ventricular tachyarrhythmias in 64 patients with schizophrenia, including 59 patients who received psychiatric medications, and five patients who did not receive psychiatric medications, and 45 healthy volunteers. None of the subjects had a history of cardiac disease or showed any abnormality in chest radiograph and transthoracic echocardiographic studies. None of the subjects had electrolyte abnormality. None of the subjects were taking drugs known to influence the QT interval, other than psychiatric medications. RESULTS: QTc and QTc dispersion were significantly (P < 0.017) increased in patients who received psychiatric medications compared with patients who did not receive psychiatric medications, or with healthy volunteers [QTc: 0.442 (0.029), 0.418 (0.029), 0.417 (0.028) s, QTc dispersion: 0.054 (0.013), 0.038 (0.017), 0.038 (0.009) s]. Daily ventricular premature beats were 183 (689), 77 (23), and 86 (149), respectively. No ventricular tachycardia was observed. There were no correlation between QTc and QTc dispersion and ventricular premature beats. CONCLUSION: Long-term treatment with antipsychotic drugs in conventional doses prolonged both QTc and QTc dispersion in patients with schizophrenia, but did not increase ventricular tachyarrhythmias in patients with schizophrenia in the absence of cardiac disease. However, despite the negative findings, ventricular tachyarrhythmias may occur as a rare side-effect of antipsychotic drugs, particularly if a patient has additional risk factors.

Adult↗
PubMed1999

A study for the proper application of urinary naphthols, new biomarkers for airborne polycyclic aromatic hydrocarbons.

Urinary naphthols, 1- and 2-naphthol, recently have been suggested as route-specific biomarkers for exposure to airborne polycyclic aromatic hydrocarbons. For the proper application of urinary naphthols as biomarkers, we studied effects of lifestyle on urinary naphthols levels in 119 Japanese male workers. After improving the detection limit of urinary naphthols up to 0.27 microg/L by high-resolution capillary gas chromatography/mass spectrometry/selected ion monitoring, urinary naphthols were detectable in approximately 90% of the subjects. Among detectable samples, the geometrical mean (GM) of urinary 1-naphthol concentration was 5.13 microg/L (geometrical standard deviation, GSD, 4.90), while the GM of urinary 2-naphthol concentration was 3.16 microg/L (GSD, 5.61). We observed that urinary 1- and 2-naphthol level were three- and sevenfold higher, respectively, among smokers than among nonsmokers (p < 0.01). The ratios of urinary 2-naphthol to 1-naphthol were significantly higher among smokers than nonsmokers (p < 0.05). The number of cigarettes smoked and urinary cotinine levels were also positively related to the concentration of urinary naphthols (p < 0.01), while other lifestyle factors, i.e., age and consumption of alcohol, greasy or salty food, sweets, fruits, vegetables, meat, or fish, were not. We also studied whether genetic polymorphisms of enzymes, which were involved in naphthalene metabolism, affected urinary naphthols levels. The cytochrome P450 (CYP) 1A1 exon 7 genetic polymorphism was not related to urinary naphthol levels. Among smokers, the subjects with c1/c2 or c2/c2 type of CYP2E1, which was determined by CYP2E1 RsaI polymorphism in 5'-flaking region, showed higher concentrations of urinary 2-naphthol than the subjects with c1/c1 type regardless of creatinine-correction (p < 0.05) and the subjects with glutathione S-transferase (GST) M1 deficient type showed higher concentrations of both urinary 1- and 2-naphthol than those with GSTM1 normal type but only without creatinine-correction (p < 0.05). Thus, when urinary naphthols are used as biomarkers, smoking and the genetic polymorphisms of CYP2E1 and GSTM1 should be considered.

Adult↗
PubMed1999

Nitric oxide release from coronary vasculature before, during, and following cardioplegic arrest.

Nitric oxide (NO) is known as a vasodilatory molecule synthesized by vascular endothelium. The NO-dependent vasodilatory response of coronary artery is impaired after ischemia and reperfusion. In the present study, the release of NO from coronary vasculature was evaluated before and during cardioplegic arrest and after reperfusion. Nine patients undergoing heart surgery were studied. Multidose crystalloid cardioplegics were used for myocardial protection. The coronary affluent and effluent were obtained simultaneously before cardioplegic arrest, at each cardioplegic administration, and after reperfusion; and the levels of nitrite and nitrate, the stable end-products of NO, were measured. The NO release from the coronary vasculature was determined as the difference in the levels of nitrite and nitrate between the coronary effluent and affluent. The level of nitrite/nitrate release from coronary vasculature was 6.8 +/- 3.7 microM before cardioplegic arrest. During cardioplegic arrest the nitrite/nitrate release decreased, reaching 1.3 +/- 1.3 microM (p < 0.05, vs. before cardioplegic arrest) at the fourth administration of the cardioplegic. At 3 to 5 minutes after reperfusion, nitrite/nitrate release further decreased to 0.36 +/- 0.34 microM (p < 0.05, vs. before cardioplegic arrest). During cardioplegic arrest the NO release decreased and reached significance at approximately 70 minutes of cardioplegic arrest compared to that before cardioplegic arrest. After reperfusion, NO release was further reduced, with statistical significance compared to that before cardioplegic arrest. Our data may indicate that cardioplegic arrest and reperfusion cause endothelial dysfunction.

Aged↗
PubMed1999

Effects of sevoflurane anesthesia on plasma inorganic fluoride concentrations during and after cardiac surgery.

PURPOSE: Sevoflurane metabolism results in the production of inorganic fluoride, which is known to be nephrotoxic. Since marked changes in body temperature and hemodynamics in cardiac surgery affect sevoflurane metabolism, plasma inorganic fluoride concentrations may differ in this situation compared with other types of surgery. We therefore measured plasma inorganic fluoride concentrations during and after sevoflurane anesthesia in patients undergoing cardiac surgery. METHODS: Sixteen patients undergoing coronary artery bypass grafting or valve replacement were premedicated with 5-10 mg midazolam and 0.5 mg scopolamine injected intramuscularly. Anesthesia was induced with 5-10 mg midazolam, 0.5-1 mg fentanyl, and 0.12-0.15 mg.kg(-1) vecuronium. Following tracheal intubation, anesthesia was maintained with oxygen, sevoflurane, and fentanyl. At the onset of cardiopulmonary bypass (CPB), sevoflurane was discontinued, and additional fentanyl, midazolam, and pancuronium were administered. Plasma inorganic fluoride concentrations were measured before anesthesia, immediately before and after CPB, and at 0, 2, 6, 12, 24, and 48 h after anesthesia. RESULTS: The individual maximum plasma inorganic fluoride concentration was 19.2 +/- 7.2 micromol.l(-1) (mean +/- SD; range, 9.2-36.7). The mean plasma inorganic fluoride concentrations increased during anesthesia, but the rate of increase decreased after the initiation of CPB. Concentrations peaked at 2 h after anesthesia and decreased thereafter. The concentrations in three cases continued to increase 2 h after anesthesia. CONCLUSION: The plasma inorganic fluoride concentrations observed in patients undergoing cardiac surgery were below nephrotoxic levels. However, the decrease in mean fluoride concentration after anesthesia was slower than that in the previous study in general surgical patients.

Journal Article↗
PubMed1999

The preoperative administration of lentinan ameliorated the impairment of natural killer activity after cardiopulmonary bypass.

The aim of this study was to determine whether the preoperative administration of lentinan, which is used clinically to activate T cell function in cancer patients, prevents the impairment of lymphocyte function after cardiopulmonary bypass (CPB). A total of 25 adults undergoing coronary artery bypass grafting were enrolled in this study. Lentinan (2 mg) was given to 10 randomly selected patients 7 d before surgery, while the other 15 patients were considered as a control. The white blood cell count, percentage of lymphocytes, subsets of lymphocytes, and natural killer cell activity were measured preoperatively, immediately after CPB and 1, 3, and 6 d after surgery. The white blood cell counts and the percentage of lymphocytes were not significantly different between the two groups; however, the percentage of CD4-positive cells in the lentinan group recovered to normal more rapidly than in the control group. Although natural killer cell activity was impaired in the control group after CPB, it maintained a nearly normal level in the lentinan group. The preoperative administration of lentinan for patients undergoing CPB ameliorated the impairment of natural killer activity and promoted the rapid recovery of CD4-positive cells.

Adjuvants, Immunologic↗
PubMed1999

Coronary arteriovenous fistulas with giant aneurysm: two case reports.

Coronary arteriovenous fistulas are rare, particularly in association with coronary aneurysms. Two rare cases of patients with coronary arteriovenous fistulas and giant aneurysmal formation are described. A right coronary fistula that drained into the superior vena cava was demonstrated in one patient. The remaining patient had a documented left coronary fistula that drained into a main pulmonary artery and had evidence of several plexal vessels that transversed through the pulmonary trunk and toward the pericardial reflex. Under cardiopulmonary bypass, the fistulas and plexal vessels were successfully ligated without any injury to the native coronary circulation.

Adult↗
PubMed1999

NAT2 gene polymorphism as a possible marker for susceptibility to bladder cancer in Japanese.

BACKGROUND: N-acetyltransferase (NAT) is known to metabolize the carcinogen arylamine. The polymorphism of the NAT2 gene is an important determinant of individual susceptibility to bladder cancer. There are significant interethnic differences in NAT2 allele frequencies. The relationship between NAT2 genotypes and bladder cancer in a Japanese population was investigated. METHODS: A case control study on 85 bladder cancer patients and 146 control subjects was conducted. NAT2 alleles were differentiated by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) methods using originally created PCR primers and genomic DNA extracted from peripheral white blood cells. The NAT2 genotypes were determined by the combination of three known NAT2 mutant type alleles (M1, M2, M3) and the wild type allele. RESULTS: NAT2 slow genotypes were associated with bladder cancer risk (odds ratio adjusted for age and gender, 4.23; 95% confidence interval [CI], 1.76-10.81). Among those with NAT2 slow genotypes/smoker, there was a significantly increased risk of 7.80 (95% CI, 1.66-57.87) when the NAT2 rapid genotypes/non-smoker were considered the reference group. This suggested a possible interaction between NAT2 slow genotypes/smoking status and bladder cancer risk. It was also shown that bladder cancer patients with NAT2 slow genotypes were more likely to have a high grade tumor (G3) or an advanced stage tumor (pT2-pT4) [corrected]. However, no association between NAT2 genotypes and the survival rate of invasive bladder cancer patients was recognized. CONCLUSION: It was demonstrated that the NAT2 slow acetylation genotype is an important genetic determinant for bladder cancer in a Japanese population.

Acetylation↗
PubMed1999

A newly designed adapter for testing an ex vivo mitral valve apparatus.

Few instruments are currently available to test mitral valve function in an ex vivo state due to the technical difficulties involved. To investigate the native ex vivo mitral valve or prosthetic mitral valve with chordae, we developed a mitral valve adapter with an annulus suturing portion and 2 papillary muscle suturing sites that can be changed in angle, direction, and length of chordae. We used this adapter to test an ex vivo mitral apparatus in beagle dogs and evaluated the morphology and function of the mitral apparatus by endoscopy. Our newly designed mitral valve adapter proved extremely useful for examining the ex vivo mitral valve anatomy and function and for testing stentless mitral prostheses with annular-papillary muscle continuity.

Animals↗
PubMed1999

Deletion polymorphism in the gene for angiotensin-converting enzyme is not a risk factor predisposing to abdominal aortic aneurysm.

OBJECTIVE: to establish whether deletion of the angiotensin-converting enzyme (ACE) gene is a risk factor predisposing to abdominal aortic aneurysm (AAA) or not. METHODS: the study included 125 patients with AAA and 153 controls randomly selected from 328 individuals. The control subjects were confirmed not to have an AAA, but matched with the AAA group for age, sex, hypertension, diabetes mellitus, and hyperlipidaemia. The presence of ACE polymorphism was detected by a polymerase chain reaction using DNA extracted from blood. RESULTS: the distribution of ACE genotypes and allele frequencies in the control and AAA groups was not significantly different. CONCLUSION: the deletion polymorphism in the ACE gene is not a risk factor for AAA.

Aged↗
PubMed1999

Immunolocalization of transcription factor AP1 in human ocular surface epithelia.

PURPOSE: The present study examined whether normal human ocular surfcae epithelia express AP1 components. Changes in expression patterns of these components in a case of ocular surface epithelial dysplasia was also evaluated before and after topical mitomycin C treatment. METHODS: Specimens of normal corneas (n = 2) and conjunctiva (n = 4) were obtained from 4 patients during cataract surgery or post mortem, while specimens of dysplastic epithelial tissue from the limbus were obtained from one patient. Specimens were immunohistochemically studied using antibodies against components of AP1. RESULTS: The normal corneal epithelium showed no staining with antibodies against c-Fos, Fra-2, FosB, c-Jun or JunB, whereas the limbal and bulbar conjunctival epithelia were positive for c-Fos, Fra-2, and c-Jun. Anti-FosB and -JunB antibodies reacted weakly with the conjunctival epithelium. JunD was absent in normal corneal and conjunctival epithelia. The dsyplastic epithelium showed positive labelling for c-Fos, Fra-2, c-Jun, and JunD throughout its thickness. Fra-1 was present in all specimens of epithelia examined. The dysplastic epithelium treated with mitomycin C was not labeled by anti-c-Fos or -Fra-2 antibody. CONCLUSION: Individual AP1 components show specific expression patterns in normal ocular surface epithelia and a case of dysplastic epithelium before and after topical MMC treatment, implying that these factors may play important roles in modulating epithelial cell function, e.g., proliferation and differentiation.

Adult↗
PubMed1999

Sevoflurane requirements for tracheal intubation with and without fentanyl.

We studied 80 healthy ASA 1 patients (aged 20-52 yr) to determine if fentanyl affects sevoflurane requirements for achieving 50% probability of no movement in response to laryngoscopy and tracheal intubation (MAC-TI). Patients were allocated randomly to one of four fentanyl dose groups (0, 1, 2 and 4 micrograms kg-1). Patients in each group received sevoflurane at a pre-selected end-tidal concentration according to an 'up-down' technique. After steady state sevoflurane concentration had been maintained for at least 10 min, fentanyl was administered i.v. Tracheal intubation was performed 4 min after administration of fentanyl, and patients were assessed as moving or not moving. Heart rate (HR) and mean arterial pressure (MAP) were recorded before induction of anaesthesia, just before administration of fentanyl, just before laryngoscopy for intubation, and after intubation. The MAC-TI of sevoflurane was 3.55% (95% confidence intervals 3.32-3.78%), and this was reduced markedly to 2.07%, 1.45% and 1.37% by addition of fentanyl 1, 2 and 4 micrograms kg-1, with no significant difference in the reduction between 2 and 4 micrograms kg-1, showing a ceiling effect. Fentanyl attenuated haemodynamic responses (HR and MAP) to tracheal intubation in a dose-dependent manner, even with decreasing concomitant sevoflurane concentration. Fentanyl 4 micrograms kg-1 suppressed the changes in HR and MAP more effectively than fentanyl 1 or 2 micrograms kg-1 at sevoflurane concentrations close to MAC-TI.

Adult↗
PubMed1999

Conformations of vertebrate striated muscle myosin monomers in equilibrium with filaments.

Porcine cardiac myosin monomers in equilibrium with filaments under physiological conditions were observed to have two conformations, extended and folded forms, upon electron microscopy and gel filtration HPLC. The conformational state was independent of ATP and the phosphorylation of regulatory light chain. The folded monomers of cardiac myosin were mainly in an open conformation with only one bend in the tail, and may not trap the hydrolysis products of ATP, as assessed by single turnover experiments. These properties are similar to those of the folded monomers of rabbit skeletal myosin [Katoh, T., Konishi, K., and Yazawa, M. (1998) J. Biol. Chem. 273, 11436-11439]. The conformational states of skeletal and cardiac myosin monomers were not affected by pH between 7.0 and 8.5. Although significant disassembly of filaments and thus an increase in the monomer concentration were observed with an increase in pH. The results indicate that the pH-dependent change in filament assembly is due to a shift of equilibrium between the filaments and extended monomers toward filament disassembly. The Mg2+-ATPase activity of these myosin monomers decreased with a decrease in the salt concentration below approximately 0.1 M, suggestive of the formation of a closed conformation similar to the conformation of 10S smooth myosin. The results suggest that the conformational change from the extended to the folded form is a common property of various myosin IIs.

Actin Cytoskeleton↗
PubMed1999

Sulfating-activity and stability of cDNA-expressed allozymes of human phenol sulfotransferase, ST1A3*1 ((213)Arg) and ST1A3*2 ((213)His), both of which exist in Japanese as well as Caucasians.

We recently found single amino acid substitutions ((213)Arg/His and (223)Met/Val) in polymorphic human phenol-sulfating phenol sulfotransferase (SULT: cDNAs encoding ST1A3, P PST or HAST1/2) among Caucasians and African-Americans. In a Japanese population (n = 143), allele frequencies of (213)Arg and (213)His were 83.2 and 16. 8%, respectively, but the (223)Val allele was not found. (213)His homozygosity was reportedly associated with both very low (>7-fold) sulfating activities of p-nitrophenol (at 4 microM) and low thermostability in platelets. Sulfating-activity determinations using recombinant (213)Arg- and (213)His-forms (ST1A3*1 and ST1A3*2, respectively) did not, however, reveal appreciable deficiency in [(35)S]3'-phosphoadenosine 5'-phosphosulfate (PAPS)-dependent sulfation of p-nitrophenol (4 microM) by ST1A3*2 (7.5 vs. 10.2 nmol/min/nmol SULT for ST1A3). Kinetic parameters for p-nitrophenol for p-nitrophenol sulfation supported the slight decrease in sulfating activities at 4 microM (K(m), 0.82 vs. 1.75 microM; V(max), 13.2 vs. 13.1 nmol/min/nmol SULT, respectively, for ST1A3*1 and *2). p-Nitrophenyl sulfate-dependent 2-naphthol sulfation by ST1A3*2 was 69% of that by ST1A3*1 (p<0.05). However, ST1A3*2 was remarkably unstable at 45 and 37 degrees C as compared to ST1A3*1. The lower p-nitrophenol sulfating activity of ST1A3*2 may explain the lower platelet p-nitrophenol sulfation in ST1A3*2 homozygotes. Protein instability and ST1A3 gene regulation may be both involved in the polymorphism of p-nitrophenol sulfation in human tissues.

Arylsulfotransferase↗
PubMed1999

The effect of fentanyl on sevoflurane requirements for somatic and sympathetic responses to surgical incision.

BACKGROUND: Fentanyl produces a reduction in the minimum alveolar concentration (MAC) of isoflurane and desflurane needed to blockade adrenergic response (BAR) to surgical incision in 50% of patients (MAC-BAR). MAC-BAR of sevoflurane and the reduction in MAC-BAR of sevoflurane by fentanyl have not been described previously. The purpose of this study was to determine the MAC and MAC-BAR reduction of sevoflurane by fentanyl with and without nitrous oxide (N2O). METHODS: Two hundred twenty-six patients were randomly assigned to one of two groups: a sevoflurane group and a sevoflurane/N2O group. Patients in each group were randomly assigned to one of five different fentanyl concentration subgroups. Patients were anesthetized with sevoflurane and fentanyl in the sevoflurane group and with sevoflurane, fentanyl, and N2O (66 vol%) in the sevoflurane/N2O group. Somatic and sympathetic responses to surgical incision were observed for MAC and MAC-BAR assessment at predetermined concentrations of sevoflurane. RESULTS: Fentanyl produced an initial steep reduction in the MAC and MAC-BAR of sevoflurane, with 3 ng/ml resulting in a 61% reduction in MAC and an 83% reduction in MAC-BAR. A ceiling effect was observed for MAC and MAC-BAR, with 6 ng/ml fentanyl providing only an additional 13% and 9% reduction in MAC and MAC-BAR, respectively. In the presence of 66 vol% N2O, MAC and MAC-BAR of sevoflurane were reduced with increasing concentrations of fentanyL A ceiling effect was not observed for reduction in MAC and MAC-BAR in the presence of N2O. CONCLUSIONS: MAC and MAC-BAR decreased similarly with increasing concentrations of fentanyl in plasma, showing an initial steep reduction followed by a ceiling effect. In the presence of N2O, MAC and MAC-BAR decreased similarly but did not exhibit a ceiling effect.

Adult↗