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Kiyoaki Watanabe

Publications and source records attributed to Kiyoaki Watanabe.

At least 19 recordsLinked to original sources
PubMed2004

High throughput multiple combination extraction from large scale polymorphism data by exact tree method.

Single nucleotide polymorphisms (SNPs) are increasingly becoming important in clinical settings as useful genetic markers. For the evaluation of genetic risk factors of multifactorial diseases, it is not sufficient to focus on individual SNPs. It is preferable to evaluate combinations of multiple markers, because it allows us to examine the interactions between multiple factors. If all the combinations possible were evaluated round-robin, the number of calculations would rapidly explode as the number of markers analyzed increased. To overcome this limitation, we devised the exact tree method based on decision tree analysis and applied it to 14 SNP data from 68 Japanese stroke patients and 189 healthy controls. From the obtained tree models, we succeeded in extracting multiple statistically significant combinations that elevate the risk of stroke. From this result, we inferred that this method would work more efficiently in the whole genome study, which handles thousands of genetic markers. This exploratory data mining method will facilitate the extraction of combinations from large-scale genetic data and provide a good foothold for further verificatory research.

Adult↗
PubMed2004

Genetic analyses and expression studies identified a novel mutation (W486C) as a molecular basis of congenital coagulation factor XII deficiency.

We analyzed the factor XII (FXII) gene of a patient with congenital FXII deficiency and identified a novel amino acid substitution (W486C) in the catalytic domain. The proband was an asymptomatic 49-year-old Japanese female with abnormal coagulation test, discovered by chance. The FXII activity and antigen level were both under 10%, suggesting a cross-reacting material-negative FXII deficiency. Sequence analysis of the proband's FXII gene revealed a homozygous nucleotide substitution G --> C in exon 12, resulting in the amino acid substitution W486C in the catalytic domain. We constructed the mutant FXII cDNA in an expression plasmid vector and transfected it into Chinese hamster ovary cells. The recombinant wild-type FXII antigen was detected in the culture medium by immunoprecipitation assay, but the mutant FXII (W486C) was not observed. On the other hand, both the wild-type FXII and W486C cell lysates contained FXII antigen and FXII mRNA, as estimated by western blotting and quantitative reverse transcriptase-polymerase chain reaction. These findings suggest that the W486C substitution of FXII impairs intracellular processing of the protein and/or transport system.

Amino Acid Substitution↗
PubMed2004

[Genetic risk factors for ischemic cerebrovascular disease--analysis on fifteen candidate prothrombotic gene polymorphisms in the Japanese population].

Accumulating evidence suggests that several polymorphisms in factors regulating blood coagulation, platelet function, and lipid metabolism are relevant for susceptibility to ischemic cerebrovascular diseases (CVD). The present study analyzed 15 genetic polymorphisms possibly associated with atherosclerosis and thrombosis in a case-control study involving a total of 200 genetically unrelated Japanese patients with ischemic CVD (mean age 58.3 +/- 7.6 y) and 281 age- and gender-matched control subjects (59.0 +/- 4.1 y). Control subjects were randomly selected from unrelated donors with no history of documented CVD or any type of cardiovascular disease with normal resting electrocardiograms. Among the factors genotyped, two factors, platelet glycoprotein (GP) Ib alpha (Thr145Met) and NADPH oxidase p22phox (His72Tyr), were significantly associated with CVD after adjustment for acquired risk factors including hypertension, diabetes mellitus, hyperlipidemia, and smoking. For those with age < 60 y, 10.6% of the CVD patients and 2.9% of the control subjects had both of the two risk genotypes (GPIb alpha 145Met and p22phox 72Tyr, p < 0.05). The mean onset-age of CVD was 58.6 +/- 7.7 y for those having no or only one risk genotype, while 53.3 +/- 5.5 y for those having both of the risk genotypes (p < 0.05). Thus, GPIb alpha 145Met and p22phox 72 Tyr are the genetic factors associated with the risk of ischemic CVD in the Japanese. Carrying both of the two mutations might be associated with developing CVD at a younger age.

Aged↗
PubMed2004

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2002). I. Susceptibility distribution].

The bacterial strains isolated from 491 patients diagnosed as having urinary tract infections (UTIs) in 13 institutions in Japan were supplied between August 2002 and July 2003. The susceptibilities of them to many kinds of antimicrobial agents were investigated. Of them, 578 strains were estimated as causative bacteria and used for the investigation. The number of them was 578 strains consisting of 177 gram-positive bacterial strains (30.6%) and 401 gram-negative bacterial strains (69.4%). Against Staphylococcus aureus, vancomycin (VCM) showed a strong activity and prevented the growth of all strains with 1 microg/mL. The susceptibility of Staphylococcus epidermidis to cephems including cefotiam (CTM) was relatively good. Against Enterococcus faecalis, ampicillin (ABPC), imipenem (IPM), and VCM showed the strongest antibacterial activity (MIC90: 2-4 microg/mL). In addition, the low sensitive strains (MIC: > or = 256 microg/mL) to clarithromycin (CAM) were detected at 48.3% but none to cefozopran (CZOP). The antibacterial activity of cephems to Escherichia coli was generally good, and especially CZOP and cefpirome (CPR) showed the highest activity (MIC90: < or = 0.125 microg/mL). Quinolone resistant E. coli was detected at frequency of 13.5%, which was higher than that in the last year. The antibacterial activity of cephems to Citrobacter freundii was generally low but CZOP and CPR had a strong acitivity (MIC90: 0.25 and 0.5 microg/mL, respectively). The antibacterial activity of cephems to Klebsiella pneumoniae was good and especially cefmenoxime (CMX), cefixime (CFIX), flomoxef (FMOX), CPR, and CZOP showed stronger activity (MIC90: < or = 0.125 microg/mL). Against Serratia marcescens, meropenem (MEPM) had the highest antibacterial activity followed by CPR and CZOP. Against Proteus mirabilis, CMX, ceftazidime (CAZ), CPR, MEPM, carumonam (CRMN), and levofloxacin (LVFX) showed the strongest activity (MC90: < or = 0.125 microg/mL). Among other cephems, CZOP and CFIX were also strong (MIC90: 0.25 microg/mL). The antibacterial activity of the drugs to Pseudomonas aeruginosa was generally low, and MIC90 of all the drugs were ranged from 64 to > or = 256 microg/mL except IPM and amikacin (AMK) having 16 microg/mL. The antibacterial activity of CZOP was relatively good (MIC50: 8 microg/mL).

Anti-Bacterial Agents↗
PubMed2004

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2002). II. Background of patients].

A total of 615 bacterial strains isolated from 491 patients diagnosed as having urinary tract infections (UTIs) in 13 institutions in Japan were supplied between August 2002 and July 2003. Then, the clinical background of patients were investigated such as sex, age, and type of infections and kind of bacteria, frequency of bacteria isolation by age and infections, bacteria and infections by timing of antibiotics administration, and bacteria and infections by surgical procedures. The bacterial strains were divided by the age and sex of the patients and the types of infections. In males, the number of patients aged less than 50 years was few and the complicated UTIs without indwelling catheter was observed most frequently. In the present time, the bacteria most frequently isolated were Escherichia coli. Pseudomonas aeruginosa and Enterococcus faecalis were also relatively frequently isolated. E. coli decreased and P. aeruginosa increased with the complication of the infections. E. faecalis tended to be isolated more frequently in the complicated UTIs than in the uncomplicated UTIs. With respect to the relation of these results to the age of the patients, in the uncomplicated UTIs, the isolation frequency of E. coli was the highest in all age groups, accounting for 70.8% in 20-49 years old. In the complicated UTIs without indwelling catheter, the isolation frequency of E. coli decreased with aging of the patients and was lower than that of E. faecalis in the patients aged 70 or more (18.3 vs 20.6%). In the complicated UTIs with indwelling catheter, the isolation frequency of E. coli was lower than in the uncomplicated UTIs in all age groups and P. aeruginosa and E. faecalis were more frequently isolated. In comparison of causative bacteria in UTIs between before and after the administration of antibiotics, E. coli decreased and P. aeruginosa increased after the administration in any UTIs. In comparison of causative bacteria in UTIs with or without surgery, E. coli was more frequently isolated in the patients without surgery, while P. aeruginosa was more in the patients with surgery in any UTIs. E. faecalis was more frequently isolated in the patients with surgery in uncomplicated and complicated UTIs without indwelling catheter and in the patients without surgery in complicated UTIs with indwelling catheter.

Age Factors↗
PubMed2003

Reference values for urinary steroids in Japanese newborn infants: gas chromatography/mass spectrometry in selected ion monitoring.

Urinary steroid profile analysis using gas chromatography/mass spectrometry (GC/MS) has been reported for the diagnosis of abnormal steroidogenesis in newborn infants with some success. We tried to establish the reference values of 63 urinary steroids in Japanese newborn infant, using GC/MS in selected ion monitoring (SIM) that utilizes two characteristic mass ions for each steroid for definitive identification. We studied 36 healthy full-term newborn infants (1-56 days of age) on spot urine samples to define the reference values (mg/g creatinine, median and 10-90 percentile range) and to investigate the possible difference between daytime and nighttime levels. We also studied 23 healthy adult females (20-24 years of age) on 24-hour-urine for the comparison of the reference values of newborn infants. Fifty metabolites of DHEA, pregnenolone, 17-hydroxypregnenolone, androstenedione, progesterone, 17-hydroxyprogesterone, 21-deoxycortisone, corticosterone, 18-hydroxycorticosterone, aldosterone, 18-hydroxycortisol, 11-deoxycortisol, cortisone, cortisol, and estrogen in each infant were measurable without interference, but 13 metabolites of 11-hydroxyandrostenedione, pregnenolone, 11-deoxycorticosterone, corticosterone, 11-dehydrocorticosterone, 21-deoxycortisol, 11-deoxycortisol and cortisol were unmeasurable in each infant due to the interference of fetal cortex steroids as confirmed by abnormal peak area ratios of two mass ions. All 63 metabolites in each control adult were measurable without interference. 16alpha-, 16beta-, and 15beta-hydroxy metabolites of 3beta-hydroxy-5-en-steroids, and 6beta-, 18-hydroxy and 11-oxo-metabolites of corticosteroids were significantly higher in full-term newborn infants than those in adults as previously reported. Urinary steroids showed little circadian variation in the newborn infants, indicating that spot urine can substitute for 24-hour urine.

Adult↗
PubMed2003

[Effective cooperation between clinical physicians and laboratory consultation division].

With the increase in clinical examination items, and with the specialization of clinical medicine, physicians' requests for consultations on laboratory medicine is getting more evident. However, at present in many hospitals laboratory staff do not always make appropriate answers to the questions from physicians in various fields because the laboratories are divided in terms of examination fields. In our hospital, we established a consultation division responding to every inquiry from clinical staff with a full-time technologist. At present the division is functioning very well, suggesting that laboratory technologists must build close relations with clinical staff and that the technologist's task is very diverse, not confined to just analyzing samples.

Clinical Laboratory Information Systems↗
PubMed2003

[Measurement of plasma von Willebrand factor cleaving protease in patients with varied thrombotic microangiopathy].

Thrombotic thrombocytopenic purpura(TTP) is a multisystem disorders characterized by thrombocytopenia, microangiopathic hemolytic anemia associated with red cell fragmentation, and neurological and renal symptoms. Plasma of patients with TTP has been shown to contain unusually large von Willebrand factor(vWF) multimers that may cause platelet agglutination in vivo. Recently, a metalloprotease responsible for cleavage of vWF multimers has been isolated from normal human plasma and was found to be deficient in some patients with TTP. We examined the activity of the vWF-cleaving protease(vWF-CP), by modified Furlan's method, in plasma from patients with a familial TTP, 3 acquired TTP, 4 thrombotic microangiopathy(TMA) and 2 veno-occlusive disease(VOD) associated after allo-BMT. Diluted plasma samples of patients were incubated with protease-free vWF purified from normal human plasma, in the presence of urea and barium ions. The extent of vWF degradation was assayed by electrophoresis in SDS-agarose gels and immunoblotting. Activity of vWF-CP from 12 normal plasma have been shown as 77-180%(average 115%), whereas, no vWF-CP(below 5%) was observed in plasma from familial TTP, before and after plasma exchange, although FFP infusion therapy has been effective for this patient to recover thrombocytopenia. In 3 acquired TTP, 2 patients showed lack of vWF-CP activity in plasma, and inhibitors against vWF-CP have been elucidated by plasma cross-mixing test. After extensive plasma exchange and FFP infusion followed by corticosteroid therapy, normal vWF-CP was recovered in plasma from 2 acquired TTP patients. Among BMT patients, plasma from 4 BMT-TMA showed normal vWF-CP activities as 55-111%, whereas plasma from 2 BMT-VOD revealed low vWF-CP activity, as 24% and 37%, respectively. Thus, measurement of vWF-CP is crucial to predict differentiation of primary forms of TMA to establish the pathogenesis in varied endothelial dysfunction.

ADAM Proteins↗
PubMed2003

[Pitfalls in laboratory testing for autoantibodies].

Quantitative autoantibody determination has recently can be widely used to confirm the diagnosis of autoimmune diseases, however, there are several problems with the assay methods. As pitfalls in terms of measurement methods, in this report we describe actual examples of a problem related to the analysis and of a large discrepancy between the data obtained by different methods of measurement. In the first example, the reaction solution in the microplate evaporated during the reaction process in automated analysis using an Eitest CA-RF ELISA kit, causing the values in the outermost wells to be significantly higher than in the inner wells. In the second example, there was a large discrepancy between the values obtained when the anti-dsDNA antibody of a systemic lupus erythematosus(SLE) patient was measured by radioimmunoassay(RIA) and by enzyme-linked immunosorbent assay(ELISA). The reason for the discrepancy in the second example may have been related to the method of the RIA, which used 50% ammonium sulfate in the B/F separation, and the possibility that certain patients have autoantibody that recognizes the ELISA solid-phase antigen more strongly. Accordingly, quantitative assay data for anti-dsDNA antibody, which possesses such diversity, should be evaluated with due consideration of the characteristics of the assay method and by checking them against the clinical data.

Antibody Diversity↗
PubMed2003

[Activities of antimicrobial agents against 8,474 clinical isolates obtained from 37 medical institutions during 2000 in Japan].

A survey was conducted to determine the antimicrobial activity of fluoroquinolones and other antimicrobial agents against 8,474 clinical isolates obtained from 37 Japanese medical institutions in 2000. A total of 25 antimicrobial agents were used, comprising 4 fluoroquinolones, 13 beta-lactams, minocycline, chloramphenicol, clarithromycin, azithromycin, gentamicin, amikacin, sulfamethoxazole-trimethoprim, and vancomycin. A high resistance rate of over 85% against fluoroquinolones was exhibited by methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium. Isolates showing resistance to fluoroquinolones among methicillin-resistant coagulase-negative Staphylococci, Enterococcus faecalis, and Pseudomonas aeruginosa from UTI accounted for 30-60%. However, many of the common pathogens were still susceptible to fluoroquinolones, such as Streptococcus pneumoniae (including penicillin-resistant isolates), Streptococcus pyogenes, methicillin-susceptible S. aureus (MSSA), methicillin-susceptible coagulase-negative Staphylococci, Moraxella catarrhalis, the Enterobacteriaceae family, and Haemophilus influenzae (including ampicillin-resistant isolates). About 85% of P. aeruginosa isolated from RTI were susceptible to fluoroquinolones. In conclusion, this survey of sensitivity to antimicrobial agents clearly indicated trend for increasing resistance to fluoroquinolones among MRSA, Enterococci, and P. aeruginosa isolated from UTI, although fluoroquinolones are still effective against other organisms and P. aeruginosa from RTI as has been demonstrated in previous studies.

Anti-Bacterial Agents↗
PubMed2003

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2001). I. Susceptibility distribution].

The bacterial strains isolated from patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between the period of September and December 2001. Then, the susceptibilities of them to a variety of antimicrobial agents were investigated. The number of them were 496 strains. The breakdown of these strains was Gram-positive bacteria as 29.6% and Gram-negative bacteria as 70.4%. Susceptibilities of these bacteria to antimicrobial agents were as follows; against Staphylococcus aureus, vancomycin (VCM) showed a strong activity, and this drug also had a strong activity against MRSA in preventing growth of all strains at 1 microgram/mL. In addition, arbekacin (ABK) showed strong activity with the MIC90 of 2 micrograms/mL against MRSA and prevented growth of all strains at 4 micrograms/mL. ABK also showed a strong activity against Staphylococcus epidermidis in preventing growth of all strains at 0.5 microgram/mL. Ampicillin (ABPC) and cefozopran (CZOP) showed a relatively strong activity against S. epidermidis (MIC90: 8 micrograms/mL). ABPC, imipenem (IPM), and VCM showed strong activities against Enterococcus faecalis. No increase of low-susceptible strains in E. faecalis was observed against these antimicrobial agents. Against Escherichia coli, carbapenems showed the highest activities: meropenem (MEPM) prevented growth of all strains at 0.25 microgram/mL; IPM prevented growth of all strains at 0.5 microgram/mL. CZOP and cefotiam (CTM) also showed strong activities against E. coli: MIC90 of CZOP was within 0.125 microgram/mL; MIC90 of CTM was within 0.5 microgram/mL. Quinolone-resistant E. coli was detected at frequency of 9.3%, which was lower than that in the last year, and was higher level than those in up to 1999. MEPM showed the strongest activity against Citrobacter freundii in preventing growth of all strains at 0.125 microgram/mL. Almost all drugs showed strong activities against Klebsiella pneumoniae and Proteus mirabilis, and MEPM prevented growth of all strains within 0.125 microgram/mL. Against Serratia marcescens, the MIC90 of gentamicin (GM) was the lowest value being 2 micrograms/mL, and those of IPM and carumonam were 8 and 16 micrograms/mL, respectively. Against Pseudomonas aeruginosa, almost all drugs were not so active. The MIC90 of GM was 8 micrograms/mL, those of IPM and amikacin were 16 micrograms/mL, and those of all other drugs were over than 32 micrograms/mL.

Anti-Bacterial Agents↗
PubMed2003

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2001). II. Background of patients].

Five-hundred thirty one bacterial strains isolated from 412 patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between September and December 2001. Then, the clinical background of patients were investigated such as sex, age, and type of infections, infections and kind of bacteria, frequency of bacteria isolation by age and infections, bacteria and infections by timing of antibiotics administration, and bacteria and infections by surgical procedures. With regard to the relationship between age and sex of patients and type of infections, the number of cases aged lower than 50 years was few and complicated UTIs without indwelling catheter was the most frequent in male patients. In females, the number of patients aged lower than 20 years was few. Most of female patients aged lower than 80 years had uncomplicated UTIs. As for the relationship between type of infections and kind of bacteria, Escherichia coli decreased as the infections were more complicated, and Pseudomonas aeruginosa and Enterococcus faecalis increased as the infections were more complicated. In relation of these results to age of patients, isolation frequency of E. coli gradually decreased with aging in patients aged 20 years and older with uncomplicated UTIs. The isolation frequencies of E. faecalis decreased with aging in the patients with complicated UTIs without indwelling catheter while P. aeruginosa decreased with aging in the patients with complicated UTIs with indwelling catheter. E. coli was isolated a few after administration of antibiotics, and P. aeruginosa and E. faecalis were frequently isolated after administration in the patients with all types of infections. As for type of causative organisms in UTIs and with or without surgical operation, E. coli was frequently isolated in the patients without surgery in the patients with uncomplicated UTIs and complicated UTIs without indwelling catheter, while P. aeruginosa was frequently isolated in the patients who underwent surgery in the patients with uncomplicated UTIs and complicated UTIs with indwelling catheter. In uncomplicated UTIs, isolation frequencies of Klebsiella spp., P. aeruginosa, and E. faecalis were significant in the patients with surgery. In complicated UTIs without indwelling catheter, Klebsiella spp. was frequently isolated in the patients with surgery. In complicated UTIs with indwelling catheter, S. aureus and Staphylococcus spp. were frequently isolated in the patients without surgery.

Adolescent↗
PubMed2003

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2001). III. Secular changes in susceptibility].

The bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella spp. and Pseudomonas aeruginosa) isolated from patients diagnosed as urinary tract infections (UTIs) in 10 institutions in Japan were supplied between September and December, 2001. Then, the susceptibilities of these bacteria to various antimicrobial agents were examined, and the results were compared with those obtained between 1992 and 2000. Comparison was made by classifying strains isolated from patients into those in uncomplicated UTIs and those in complicated UTIs (including with or without indwelling catheter). The drug sensitivity of S. aureus in this year was comparable to those in up to the previous year, and S. aureus showed the best susceptibility to vancomycin (VCM). E. faecalis showed good susceptibility to ampicillin and imipenem, and the MIC90s were 2 micrograms/mL. The susceptibility of E. faecalis to VCM was also good. E. coli showed good susceptibility to the drugs except penicillins. Among cephems, the susceptibility to cefozopran (CZOP) was better (MIC90: < or = 0.125 microgram/mL). Just as the last report, the decreases in susceptibility of E. coli to quinolones were also observed in the patients with complicated UTIs. The susceptibility of Klebsiella spp. to all the test drugs did not significantly change in 2001 and was generally good but not to penicillins. Among cephems, Klebsiella spp. showed good susceptibility to flomoxef, cefpirome, cefixime, and CZOP with < or = 0.125 microgram/mL of MIC90s either in uncomplicated or complicated UTIs. Although the drug sensitivity of P. aeruginosa was generally low, the detection of the strains that showed good susceptibility to quinolones and carbapenems (MIC: < or = 0.125-2 micrograms/mL) were relatively frequent.

Anti-Bacterial Agents↗
PubMed2003

Determination of laboratory reference ranges for lymphocyte immunophenotype subsets in healthy adult Japanese using flow cytometry.

This study represents a comprehensive evaluation of normative values for lymphocyte immunophenotype subsets using flow cytometry techniques in a Japanese population. Lymphocyte reference ranges were determined for percentage and absolute count of T, B, and NK cells in healthy adult Japanese using an extensive two-color immunophenotyping panel and consistently applied quality control methodology. Reference values were also determined for activation markers on CD3+ lymphocytes CD3+/CD25+, CD3+/CD38+ and CD3+/HLA-DR+. Differences in age and gender were observed for specific lymphocyte subsets. Comparison of the Japanese study with a Thai multi-center study that used similar methodology also demonstrated ethnic differences in lymphocyte reference ranges. The results in this study strongly suggest that reference values derived from studies in one population may not be applied to another population even when similar protocols for reagents, instruments and procedures are used although such studies do appear useful for epidemiological comparisons.

ADP-ribosyl Cyclase↗
PubMed2002

Novel statistical classification model of type 2 diabetes mellitus patients for tailor-made prevention using data mining algorithm.

To estimate the usefulness of data mining algorithms for extracting risk predictors of diabetic vascular complications in proper order in the future, we tried applying the Classification and Regression Trees (CART) method to the prevalence data of 165 type 2 diabetic outpatients and already known risk factors. Among the 6 categorical and 15 continuous risk factors, age (cutoff: 65.4) was the best predictor for classifying patients into groups with and without macroangiopathy (p=0.000). Body weight (cutoff: 53.9) was the best predictor (p=0.006) in the older group (age >65.4), whereas systolic blood pressure (cutoff: 144.5) was the best predictor in the remaining group (p=0.002). Age (cutoff: 64.8) was also the best predictor for categorizing them into groups with and without microangiopathy (p=0.000). In the older group (age >64.8), BMI (cutoff: 21.5) was the best predictor (p=0.001), whereas morbidity term (cutoff: 15.5) was the best predictor in the other group (p=0.01 0). Because the orders and values of all risk factors and cutoff points mined were reasonable clinically, this method may have the potential to highlight predictors in order of importance to apply tailor-made prevention of diabetic vascular complications.

Algorithms↗