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Biomedical subjects

Jun Kato

Publications and source records attributed to Jun Kato.

At least 19 recordsLinked to original sources

Risk factors and indications for colectomy in ulcerative colitis patients are different according to patient's clinical background.

PURPOSE: Despite progress in medical treatment for ulcerative colitis, a considerable fraction of ulcerative colitis patients undergo colectomy. We analyzed the clinical variables of ulcerative colitis patients and determined the risk factors and indications for colectomy. METHODS: The clinical records of 981 consecutive Japanese patients with ulcerative colitis were reviewed both retrospectively and prospectively. RESULTS: Of 981 patients with ulcerative colitis, 85 patients underwent colectomy. Multivariate analysis indicated that male gender (risk ratio, 2.16; 95 percent confidence interval, 1.37-3.42), onset year during and after 2000 (risk ratio, 2.85; 95 percent confidence interval, 1.31-6.22), severe disease activity (risk ratio, 2; 95 percent confidence interval, 1.15-3.48), corticosteroid resistance (risk ratio, 7.05; 95 percent confidence interval, 4.29-11.59), and complications because of corticosteroid administration (risk ratio, 3.55; 95 percent confidence interval, 2.08-6.06) were significant risk factors for colectomy. In patients with disease duration of more than five years, only corticosteroid resistance and complications because of corticosteroid were significant risk factors for colectomy. When we stratified indications for colectomy for the 85 cases via patient disease duration, massive hemorrhage was a relatively frequent cause of colectomy in patients with a disease duration of less than five years (P = 0.091). On the other hand, colon dysplasia or cancer was a major cause for colectomy in patients with a disease duration of more than ten years (P = 0.0001). CONCLUSIONS: In ulcerative colitis patients, the risk factors and indications for colectomy were different according to the patient's clinical background. Our findings may help to predict patients with ulcerative colitis who have a high risk for colectomy.

Adrenal Cortex Hormones↗

Risk assessment for delayed hemorrhagic complication of colonic polypectomy: polyp-related factors and patient-related factors.

BACKGROUND: Hemorrhage is among the most serious complications of colorectal polypectomy and may occur after a longer postprocedure interval. OBJECTIVE: We aimed to elucidate the risk factors for delayed postpolypectomy hemorrhage, including both polyp characteristics and the general condition of the patients. DESIGN: Retrospective cohort study. PATIENTS: A total of 6617 cases of colorectal polypectomy was performed in 3138 consecutive patients in Japan. MAIN OUTCOME MEASUREMENTS: The risk factors for delayed postpolypectomy hemorrhage were assessed among polyp characteristics (form, size, histologic features) and the method of resection by unconditional logistic regression. Patient conditions (smoking, alcohol, hypertension, diabetes mellitus, hyperlipidemia) were compared between case-control pairs matched on polyp-related characteristics by conditional logistic regression. RESULTS: Hemorrhage occurred in 38 lesions (0.57%) of 37 patients (1.2%): 22 required endoscopic hemostasis and 1 required blood transfusion. Although polyp size was associated with the occurrence of delayed hemorrhage (10.0 +/- 6.9 mm in hemorrhage cases vs 5.6 +/- 3.8 mm in others, P < .0001), other polyp-related factors were not significant. Hypertension was a complication in 25 of 37 (68%) cases and in 21 of 74 (28%) matched controls, showing an adjusted odds ratio of 5.6 (95% CI 1.8-17.2, P = .001). Other patient characteristics were not significant. The interval between polypectomy and hemorrhage was significantly longer in patients with hypertension (median 6 days, range 2-14 days) than in those without hypertension (2.5 days, 1-9 days; P = .019). LIMITATIONS: This study does not provide information regarding prevention of hemorrhage. CONCLUSIONS: Hypertension is a significant risk factor for delayed colorectal postpolypectomy hemorrhage. The interval between polypectomy and hemorrhage can be as long as 14 days in the presence of hypertension.

Aged↗

Laterally spreading type of colorectal adenoma exhibits a unique methylation phenotype and K-ras mutations.

BACKGROUND & AIMS: Laterally spreading tumors (LST), characterized by superficial extension along the colonic lumen, have recently been detected by colonoscopy. However, genetic and epigenetic characteristics of these tumors were scarcely reported. METHODS: A total of 205 sporadic colorectal adenoma tissues (157 protruded-type, 23 granular-type LST (G-LST), 12 flat-type LST (F-LST), and 13 flat-type smaller than 1 cm) were collected. CpG island methylator phenotype (CIMP) was determined by examination of methylation status at p16, methylated in tumor (MINT) 1, 2, 12, and 31 loci. K-ras codon 12 and 13 point mutations were also examined. The relationship between macroscopic appearance and CIMP status or K-ras mutations was analyzed. RESULTS: Among adenomas larger than 1 cm, CpG island methylation involving 2 or more loci (CIMP-high) was more likely to be observed in G-LST (14/23, 61%) than in protruded-type adenomas (18/73, 25%) (P = .002). The prevalence of K-ras mutations in G-LST (18/23, 78%) was significantly higher than that in protruded-type adenomas (18/73, 25%) (P < .0001). Moreover, the prevalence of CIMP-high and K-ras mutations in G-LST located in the proximal colon was much higher (11/13, 85%; and 12/13, 92%, respectively). In contrast, F-LST exhibited low prevalence of CIMP-high (1/12, 8%) and K-ras mutations (2/12, 16%). CONCLUSIONS: High prevalence of CIMP-high and K-ras mutations in G-LST, especially in the proximal colon, could strongly suggest that G-LST appearance is associated with a unique carcinogenic pathway.

Adenoma↗

PKCI-W forms a heterodimer with PKCI-Z and inhibits the biological activities of PKCI-Z in vitro, supporting the predicted role of PKCI-W in sex determination in birds.

The two chicken genes, PKCI-W on the W chromosome and PKCI-Z on the Z chromosome, belong to the gene family encoding the Hint (histidine triad nucleotide-binding protein)-branch proteins in the widely conserved HIT (histidine triad)-family. It has been speculated that PKCI-W is involved in the sex determination of birds by forming a heterodimer with PKCI-Z and inhibiting the function of PKCI-Z in female embryos. In this study, both PKCI-W and PKCI-Z were expressed in fusion [maltose-binding protein (MBP) or glutathione-S-transferase (GST)] and tagged [(His)(6) or FLAG] forms (FT-forms) in Escherichia coli and purified. Formation of homodimers of PKCI-W-containing or the PKCI-Z-containing FT-protein and the formation of a heterodimer between the PKCI-W-containing and the PKCI-Z-containing FT-proteins were demonstrated by Western blotting after GST-pulldown or binding to and elution from the Co(2+)-resin. The homodimer of PKCI-Z, but not PKCI-W, bound to an N(6)-(3- aminopropyl) adenosine affinity column and hydrolyzed adenosine 5'-monophosphoramidate. Both of these activities were inhibited in vitro in a dominant-negative manner by the formation of a heterodimer containing PKCI-W. These in vitro experimental results support the predicted role of PKCI-W in the process of sex determination in birds.

Amino Acid Sequence↗

Centrifugal leukocytapheresis therapy for ulcerative colitis without concurrent corticosteroid administration.

Corticosteroid administration is an important therapy for active ulcerative colitis. However, long-term corticosteroid use is associated with serious complications such as osteoporosis, diabetes, and growth retardation. The effect of combination therapy corticosteroid plus leukocytapheresis has been previously reported, but that of leukocytapheresis with no corticosteroid is unknown. We carried out a preliminary study of six patients (two men and four women) with active ulcerative colitis (severe in two, moderately severe in four) who did not respond to 5-aminosalicylate derivatives, but refused corticosteroid use. Centrifugal leukocytapheresis was carried out once per week totaling four sessions per course. Treatment was considered effective when patients experienced clinical remission, which was defined as a frequency of diarrhea of four times or less and absence of visible blood in the stool, after one course. Leukocytapheresis was effective in five of six patients(83%). With cases stratified by severity, both severe cases and three of four moderately severe cases showed effectiveness. Clinical activity scores according to Lichtiger et al. in cases where leukocytapheresis was effective decreased from 9.8 to 6.6 at 1 week (P < 0.0001), declining further 2.4 at the end of the course. No obvious complications of leukocytapheresis were noted except for a decrease in hemoglobin by 1 g/dL. Centrifugal leukocytapheresis without corticosteroid treatment can induce remission in patients with active ulcerative colitis, and might be particularly beneficial for patients in whom adverse effects preclude the use of corticosteroids.

Adolescent↗

Nosocomial outbreak of ceftazidime-resistant Serratia marcescens strains that produce a chromosomal AmpC variant with N235K substitution.

Serratia marcescens is a Gram-negative bacterium that is often associated with nosocomial infections. Here we analyzed the resistance mechanism of the ceftazidime-resistant S. marcescens nosocomial strains. The five S. marcescens urinary tract infection-associated isolates were positive for chromosomal ampC and bla(TEM-1). Four of the five strains, ES11, ES31, ES42, and ES46, were single clone and ceftazidime resistant. The fifth strain, ES71, was susceptible to ceftazidime. Analysis of the deduced amino acid sequence revealed a Glu-235-Lys substitution in the third amino acid of the third motif of AmpC from both ES46 and ES71, and a site-directed mutagenesis experiment confirmed that this substitution is involved in the ceftazidime resistance phenotype. However, the resistance phenotypes of strains ES46 and ES71 to ceftazidime were quite different from one another, indicating that another mechanism, in addition to the AmpC mutation, is also involved in the determination of the resistance phenotype of these strains. Basal AmpC activity was more than two times higher in strain ES46 than in ES71, which could result in the differing resistance phenotypes of these two strains. The clinical significance and prevalence of extended-spectrum cephalosporin-resistant S. marcescens strains harboring the mutated chromosomal ampC gene are unclear in Japan and remain to be elucidated.

Amino Acid Sequence↗

Leukotriene D4 potentiates fibronectin-induced migration of human lung fibroblasts.

Fibroblasts play an important role in the repair and remodeling processes following injury. Leukotriene D4 (LTD4) is a potent mediator in inflammatory processes, but the direct effect of cysteinyl leukotrienes on fibroblast migration remains unelucidated. In this study, the effect of the LTD4 on normal human lung fibroblasts (NHLF) chemotaxis induced by human plasma fibronectin (HFn) was investigated using the modified Boyden's chamber technique. LTD4 potentiated NHLF chemotaxis to HFn in concentration-dependent manner. A specific cysteinyl leukotriene receptor type 1 antagonist, pranlukast inhibited this effect, indicating that LTD4 affected cell migration via its specific receptor. The potentiating effect of LTD4 on fibroblast chemotaxis was completely abolished by pertussis toxin (PTX), suggesting that LTD4-induced effect was dependent on PTX-sensitive Gi/o signaling. These findings suggest that LTD4 has a potential to augment fibroblast chemotaxis, and to contribute to regulation of the wound healing and following remodeling in fibrotic processes of the lung.

Adjuvants, Immunologic↗

Rectosigmoid findings are not associated with proximal colon cancer: analysis of 6 196 consecutive cases undergoing total colonoscopy.

AIM: To review the risk of proximal colon cancer in patients undergoing colonoscopy. METHODS: We estimated the risk of advanced proximal adenomas and cancers in 6 196 consecutive patients that underwent colonoscopy (mean age 60 years, 65% males, without prior history of colorectal examination). Neoplasms were classified as diminutive adenoma (5 mm or less), small adenoma (6-9 mm), advanced adenoma (10 mm or more, with villous component or high-grade dysplasia) and cancer (invasive adenocarcinoma). The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal colon (from cecum to descending colon). RESULTS: The trend of the prevalence of advanced proximal adenoma was to increase with severe rectosigmoid findings, while the prevalence of proximal colon cancer did not increase with severe rectosigmoid findings. Among the 157 patients with proximal colon cancer, 74% had no neoplasm in the rectosigmoid colon. Multivariate logistic-regression analysis revealed that age was the main predictor of proximal colon cancer and existence of rectosigmoid adenoma was not a predictor of proximal colon cancer. CONCLUSION: Sigmoidoscopy is inadequate for colorectal cancer screening, especially in older populations.

Adenoma↗

Flat-type early colorectal cancer preferentially develops in right-sided colon in older patients.

BACKGROUND: Flat-type colorectal cancer is frequently reported in Japan and Europe, but its clinical features remain obscure. Thus, we investigated the clinical features of flat-type early colorectal cancer with respect to tumor location and patient age and compared them with those of polypoid-type early and advanced cancer. METHODS: Between January 1999 and June 2001, total colonoscopy was performed in 6,178 patients (mean age, 61 years; 4,290 males and 1,888 females). Of these patients, 402 patients with 429 colorectal cancers were found: 202 at advanced stage (invading beyond muscularis propria) and 227 at early stage (carcinoma in situ or invading within submucosa). Early-stage cancer was classified into two macroscopic subgroups: flat-type and polypoid-type. RESULTS: Out of 227 early cancers, 44 were flat type and 183 were polypoid. Flat-type early cancer was more frequently located in the right colon (57 percent, 25/44) than polypoid-type cancer (19 percent, 35/183; P < 0.001). Adenomatous component in flat-type early cancer was less frequent than in polypoid-type cancer (23 percent vs. 92 percent, P < 0.001). The proportion of right-sided colon in flat-type early cancer increased with age (33 percent in patients < or = 59 years, 50 percent in patients between 60 and 69 years, and 72 percent in patients > or = 70 years), whereas polypoid-type early cancer showed minimal change (16 percent, 18 percent, and 25 percent, respectively). An increase in the proportion of right-sided colon with age was also found in advanced cancer (20 percent, 38 percent, and 52 percent, respectively). CONCLUSION: The incidence of flat-type early cancer in right-sided colon increased with age, similar to the pattern of advanced cancer. This suggests that flat-type early cancer may be a precursor of advanced cancer in the right colon, especially in older people.

Adenoma↗

A comparison of the immunochemical fecal occult blood test and total colonoscopy in the asymptomatic population.

BACKGROUND & AIMS: The fecal occult blood test (FOBT) is recommended as a screening test for colorectal cancer, but there are few reliable studies on the accuracy of immunochemical FOBT. The aim of this study was to analyze the sensitivity of immunochemical FOBT and to compare the results with the findings from complete colonoscopy. METHODS: Asymptomatic adults underwent 1-time immunochemical FOBT and total colonoscopy simultaneously. The prevalence and location of colorectal neoplasia were determined by colonoscopy. The results of immunochemical FOBT and the colonoscopic findings were compared. RESULTS: Of 21,805 patients, immunochemical FOBT was positive in 1231 cases (5.6%). The sensitivity of 1-time immunochemical FOBT for detecting advanced neoplasia and invasive cancer was 27.1% and 65.8%, respectively. In addition, the sensitivity for invasive cancer according to Dukes' stage showed 50.0% for Dukes' stage A, 70.0% for Dukes' stage B, and 78.3% for Dukes' stages C or D. The sensitivity for detecting advanced neoplasia at the proximal colon was significantly lower than that detected in the distal colon (16.3% vs 30.7%, P = .00007). CONCLUSIONS: Although the screening of asymptomatic patients with immunochemical FOBT can identify patients with colorectal neoplasia to a certain extent, the sensitivity is relatively low and different according to the tumor location. Therefore, programmatic and repeated screening by immunochemical FOBT may be necessary to increase sensitivity for colorectal cancer detection.

Adult↗

Ultrathin colonoscope with a diameter of 9.8 mm for total colonoscopy.

BACKGROUND: The pediatric colonoscope is superior to the standard colonoscope in some patients with a fixed, angulated colon. A colonoscope thinner than the pediatric one is thought to outperform even the pediatric colonoscope in such cases. This study was conducted to assess the efficacy of an ultrathin colonoscope, 9.8 mm in diameter, comparing it with pediatric and standard colonoscopes. METHODS: Three types of colonoscopes were used: ultrathin, pediatric, and standard. A total of 287 consecutive patients were assigned to three groups: ultrathin (n=94), pediatric (n=98), and standard (n=95). First assessment was the ratio of cecal intubation and the reasons for unsuccessful colonoscopy. The second was the time to cecal intubation. RESULTS: Cecal intubation rates were not different among three groups (96% in each). The main reasons for failed colonoscopy were looping in the ultrathin group, and angulation or stricture in the pediatric and standard groups. Mean time to the cecum was slightly longer in the ultrathin group (6.5 minutes) than the pediatric group (5.6 minutes) and standard group (6.1 minutes), but there were no significant differences among three groups. CONCLUSION: Colonoscopy with the ultrathin colonoscope was as successful as with the pediatric and standard colonoscopes. The advantage of the ultrathin colonoscope might be notable in cases with stricture or severe angulation.

Adult↗

Determination of ultratrace amounts of ruthenium(III) by the delayed autocatalytic reaction using citric acid.

A method for determination of ultratrace amounts (ppq levels) of ruthenium(III) was developed using a copper(II)-phthalocyanine-3,4',4",4"'-tetrasulfonic sodium salt (Cu-PTS) as an indicator in a potassium bromate autocatalytic reaction system. A satisfactory calibration curve of ruthenium(III) ion was obtained by the time measurement in the concentration range of 1 x 10(-13) M to 5 x 10(-12) M with the relative standard deviation (RSD) of 2.8% (n=5). The determination limits (3sigma) were 3.30 x 10(-14) M (3.34 ppq).

Journal Article↗

[In vitro susceptibilites to levofloxacin and various antibacterial agents of 11,475 clinical isolates obtained from 52 centers in 2002].

The susceptibilities of bacteria to fluoroquinolones (FQs), especially levofloxacin, and other antimicrobial agents were investigated using 11,475 clinical isolates collected in Japan during 2002. Methicillin susceptible staphylococci, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis, the family of Enterobactericeae, Haemophilus influenzae and Acinetobacter spp. exhibited stable and high susceptibilities to FQs. The rate of FQs-resistant MRSA was 80 approximately 90%, being markedly higher than that of FQs-resistant MSSA. The FQs-resistance rate of MRCNS was also higher than that of MSCNS, however, it was lower than that of MRSA. No FQs-resistant clinical isolates of Salmonella spp. were detected in any of the surveys. Thirteen of Escherichai coli 696 isolates, 8 of Klebsiella pneumoniae 630 isolates and 33 of Proteus mirabilis 373 isolates produced extended-spectrum beta-lactamase (ESBL), furthermore 6 of 13 in E. coli, 1 of 8 in K. pneumoniae and 14 of 31 ESBL-producing isolates, and in P. mirabilis were FQs resistant. Attention should be focused in the future on the emergence of ESBL in relation to FQs resistance. The rate of FQs-resistant P. aeruginosa isolated from urinary tract infection (UTI) was 40 approximately 60%, while 15 approximately 25% of isolates from respiratory tract infection (RTI) were resistant. IMP-1 type metallo beta-lactamase producing organisms were found in 49 of P. aeruginosa 1,095 isolates, 7 of S. marcescens 586 isolates and 4 of Acinetobacter spp. 474 isolates, respectively. Glycopeptide-resistant enterococci or S. aureus was not found.

Anti-Bacterial Agents↗