Association between endoscopic findings related to colonic diverticula and bowel habits: A multicenter study in Japan.

BACKGROUND AND AIM: Few studies have shown the associations between colonic diverticula and endoscopic findings such as location, inflammation, number of diverticula, sigmoid colon rigidity, and bowel habits. METHODS: Japanese subjects who underwent total colonoscopies at six centers in Japan from November 2015 to October 2016 were analyzed. Bowel habits were evaluated using the Gastrointestinal Symptom Rating Scale. Location and number of diverticula, inflammation, and sigmoid colon rigidity were evaluated from endoscopy results. RESULTS: A total of 762 subjects (486 men and 276 women [ratio, 1.76:1]) whose mean age was 65.5 ± 11.4 years were evaluated. In multivariate analysis, presence of constipation was associated with a significantly lower likelihood of left-sided colonic diverticula (odds ratio = 0.40, 95% confidence interval 0.20-0.82, P = 0.012), whereas right-sided and bilateral-sided colonic diverticula, multiple colonic diverticula, inflammation findings, and sigmoid colon rigidity were not related to bowel habits. CONCLUSIONS: Among endoscopic findings related to colonic diverticula and bowel habits, only left-sided colonic diverticula were inversely associated with constipation, whereas inflammation findings, multiple diverticula, and sigmoid colon rigidity were not related to bowel habits. However, the association of inflammation findings with colonic diverticula and bowel habits should be further studied. Investigation of changes in left-sided colonic diverticula may lead to new treatments for constipation.

Metformin for chemoprevention of metachronous colorectal adenoma or polyps in post-polypectomy patients without diabetes: a multicentre double-blind, placebo-controlled, randomised phase 3 trial.

BACKGROUND: The prevalence of, and mortality from, colorectal cancer is increasing worldwide, and new strategies for prevention are needed to reduce the burden of this disease. The oral diabetes medicine metformin might have chemopreventive effects against cancer, including colorectal cancer. However, no clinical trial data exist for the use of metformin for colorectal cancer chemoprevention. Therefore, we devised a 1-year clinical trial to assess the safety and chemopreventive effects of metformin on sporadic colorectal cancer (assessed by adenoma and polyp recurrence) in patients with a high risk of adenoma recurrence. METHODS: This trial was a multicentre, double-blind, placebo-controlled, randomised phase 3 trial. Non-diabetic adult patients who had previously had single or multiple colorectal adenomas or polyps resected by endoscopy were enrolled into the study from five hospitals in Japan. Eligible patients were randomly assigned (1:1) to receive oral metformin (250 mg daily) or identical placebo tablets by a stratified computer-based randomisation method, with stratification by institute, age, sex, and body-mass index. All patients, endoscopists, doctors, and investigators were masked to drug allocation until the end of the trial. After 1 year of administration of metformin or placebo, colonoscopies were done to assess the co-primary endpoints: the number and prevalence of adenomas or polyps. Our analysis included all participants who underwent random allocation, according to the intention-to-treat principle. This trial is registered with University Hospital Medical Information Network (UMIN), number UMIN000006254. FINDINGS: Between Sept 1, 2011, and Dec 30, 2014, 498 patients who had had single or multiple colorectal adenomas resected by endoscopy were enrolled into the study. After exclusions for ineligibility, 151 patients underwent randomisation: 79 were assigned to the metformin group and 72 to the placebo group. 71 patients in the metformin group and 62 in the placebo group underwent 1-year follow-up colonoscopy. The prevalence of total polyps (hyperplastic polyps plus adenomas) and of adenomas in the metformin group was significantly lower than that in the placebo group (total polyps: metformin group 27 [38·0%; 95% CI 26·7-49·3] of 71 patients, placebo group 35 [56·5%; 95% CI 44·1-68·8] of 62; p=0·034, risk ratio [RR] 0·67 [95% CI 0·47-0·97]; adenomas: metformin group 22 [30·6%; 95% CI 19·9-41·2] of 71 patients, placebo group 32 [51·6%; 95% CI 39·2-64·1] of 62; p=0·016, RR 0·60 [95% CI 0·39-0·92]). The median number of polyps was zero (IQR 0-1) in the metformin group and one (0-1) in the placebo group (p=0·041). The median number of adenomas was zero (0-1) in the metformin group and zero (0-1) in the placebo group (p=0·037). 15 (11%) of patients had adverse events, all of which were grade 1. We recorded no serious adverse events during the 1-year trial. INTERPRETATION: The administration of low-dose metformin for 1 year to patients without diabetes was safe. Low-dose metformin reduced the prevalence and number of metachronous adenomas or polyps after polypectomy. Metformin has a potential role in the chemoprevention of colorectal cancer. However, further large, long-term trials are needed to provide definitive conclusions. FUNDING: Ministry of Health, Labour and Welfare, Japan.

The crystal structure of maleylacetate reductase from Rhizobium sp. strain MTP-10005 provides insights into the reaction mechanism of enzymes in its original family.

Maleylacetate reductase plays a crucial role in catabolism of resorcinol by catalyzing the NAD(P)H-dependent reduction of maleylacetate, at a carbon-carbon double bond, to 3-oxoadipate. The crystal structure of maleylacetate reductase from Rhizobium sp. strain MTP-10005, GraC, has been elucidated by the X-ray diffraction method at 1.5 Å resolution. GraC is a homodimer, and each subunit consists of two domains: an N-terminal NADH-binding domain adopting an α/ß structure and a C-terminal functional domain adopting an α-helical structure. Such structural features show similarity to those of the two existing families of enzymes in dehydroquinate synthase-like superfamily. However, GraC is distinct in dimer formation and activity expression mechanism from the families of enzymes. Two subunits in GraC have different structures from each other in the present crystal. One subunit has several ligands mimicking NADH and the substrate in the cleft and adopts a closed domain arrangement. In contrast, the other subunit does not contain any ligand causing structural changes and adopts an open domain arrangement. The structure of GraC reveals those of maleylacetate reductase both in the coenzyme, substrate-binding state and in the ligand-free state. The comparison of both subunit structures reveals a conformational change of the Tyr326 loop for interaction with His243 on ligand binding. Structures of related enzymes suggest that His243 is likely a catalytic residue of GraC. Mutational analyses of His243 and Tyr326 support the catalytic roles proposed from structural information. The crystal structure of GraC characterizes the maleylacetate reductase family as a third family in the dehydroquinate synthase-like superfamily. Proteins 2016; 84:1029-1042. © 2016 Wiley Periodicals, Inc.

Risk factors for small-bowel mucosal breaks in chronic low-dose aspirin users: data from a prospective multicenter capsule endoscopy registry.

BACKGROUND: To develop appropriate management strategies for patients who take low-dose aspirin, it is important to identify the risk factors for GI injury. However, few studies have described the risk factors for small-bowel injury in these patients. OBJECTIVE: To investigate factors influencing the risk of small-bowel mucosal breaks in individuals taking continuous low-dose aspirin. DESIGN: Capsule endoscopy data were collected prospectively from 5 institutions. SETTING: Yokohama City University Hospital and 4 other hospitals. PATIENTS: A total of 205 patients receiving treatment with low-dose aspirin for over 3 months. INTERVENTIONS: Colonoscopic and upper GI endoscopy had been performed in all of the patients before the capsule endoscope evaluation. MAIN OUTCOME MEASUREMENTS: Risk factors for small-bowel mucosal breaks. RESULTS: Of the 198 patients (141 male; mean age 71.9 years) included in the final analysis, 114 (57.6%) had at least 1 mucosal break. Multivariate analysis identified protein pump inhibitor (PPI) use (OR 2.04; 95% confidence interval [CI], 1.05-3.97) and use of enteric-coated aspirin (OR 4.05; 95% CI, 1.49-11.0) as independent risk factors for the presence of mucosal breaks. LIMITATIONS: Cross-sectional study. CONCLUSION: PPI use appears to increase the risk of small-bowel injury in patients who take continuous low-dose aspirin. Clinicians should be aware of this effect of PPIs; new strategies are needed to treat aspirin-induced gastroenteropathy.

Metabolic factors accelerate colorectal adenoma recurrence.

BACKGROUND: Metabolic factors have been reported to increase the prevalence of colorectal adenomas, however, whether metabolic factors might also accelerate the recurrence after removal of adenomas has not yet been discussed. In this retrospective multicenter study, we clarified the risk factors for adenoma recurrence focusing on metabolic factors. METHODS: We analyzed the medical records of 43,195 patients who had undergone colonoscopy between January 2005 and December 2011 at 5 hospitals in Japan. Of these, the data of 1111 patients who had undergone removal of adenomas at the first screening colonoscopy, and then been followed up by colonoscopy 1 year and 2 years later were analyzed. RESULTS: The following 8 factors were demonstrated with a multivariate analysis as being associated with colorectal adenomas recurrence: for adenoma-related factors, 5 factors (villous features, grade of dysplasia, location and size of the largest removed adenoma, and number of the removed adenomas) were identified; for metabolic factors and other factors, 3 factors (age, body mass index (BMI), and fasting blood glucose (FBG)) were identified. A risk score (0-10 points) was developed based on these 8 factors. The risk of adenoma recurrence increased as the risk score increased. When the risk score was ≥3 (3-10) points, the odds ratio relative to <3 (0-2) points was 7.07 (95% CIs 5.30-9.43). CONCLUSIONS: In addition to adenoma-related factors (villous features, grade of dysplasia, location, size and number), 3 factors (age, BMI and FBG) were demonstrated to influence the recurrence rate of colorectal adenoma. When the risk score was ≥3, the risk of recurrence was significantly elevated.

Frequency and risk factors for rebleeding events in patients with small bowel angioectasia.

BACKGROUND: Small bowel angioectasia is reported as the most common cause of bleeding in patients with obscure gastrointestinal bleeding. Although the safety and efficacy of endoscopic treatment have been demonstrated, rebleeding rates are relatively high. To establish therapeutic and follow-up guidelines, we investigated the long-term outcomes and clinical predictors of rebleeding in patients with small bowel angioectasia. METHODS: A total of 68 patients were retrospectively included in this study. All the patients had undergone CE examination, and subsequent control of bleeding, where needed, was accomplished by endoscopic argon plasma coagulation. Based on the follow-up data, the rebleeding rate was compared between patients who had/had not undergone endoscopic treatment. Multivariate analysis was performed using Cox proportional hazard regression model to identify the predictors of rebleeding. We defined the OGIB as controlled if there was no further overt bleeding within 6 months and the hemoglobin level had not fallen below 10 g/dl by the time of the final examination. RESULTS: The overall rebleeding rate over a median follow-up duration of 30.5 months (interquartile range 16.5-47.0) was 33.8% (23/68 cases). The cumulative risk of rebleeding tended to be lower in the patients who had undergone endoscopic treatment than in those who had not undergone endoscopic treatment, however, the difference did not reach statistical significance (P = 0.14). In the majority of patients with rebleeding (18/23, 78.3%), the bleeding was controlled by the end of the follow-up period. Multiple regression analysis identified presence of multiple lesions (≥3) (OR 3.82; 95% CI 1.30-11.3, P = 0.02) as the only significant independent predictor of rebleeding. CONCLUSION: In most cases, bleeding can be controlled by repeated endoscopic treatment. Careful follow-up is needed for patients with multiple lesions, presence of which is considered as a significant risk factor for rebleeding.

Assessment of small bowel motility in patients with chronic intestinal pseudo-obstruction using cine-MRI.

OBJECTIVES: Chronic intestinal pseudo-obstruction (CIPO) is a rare, serious motility disorder, with life-threatening complications over time. However, lack of an established, non-invasive diagnostic method has caused delays in the diagnosis of this intractable disease. Cine-magnetic resonance imaging (MRI) is an emerging technique, with a potential to evaluate the motility of the entire bowel. We compared small bowel motility in healthy volunteers, patients with irritable bowel syndrome (IBS), and those with CIPO, using cine-MRI, and evaluated the usefulness of cine-MRI as a novel diagnostic method for CIPO. METHODS: Twelve healthy volunteers, IBS patients, and CIPO patients prospectively underwent cine-MRI at 1.5 T. Luminal diameter, contraction ratio, and contraction cycle were measured and compared between the groups. RESULTS: Cine-MRI provided sufficient dynamic images to assess the motility of the entire small bowel. Luminal diameter (mean±s.d.) in CIPO patients was significantly higher than that in healthy volunteers and IBS patients (43.4±14.1, 11.1±1.5, and 10.9±1.9 mm, respectively), and contraction ratio was significantly lower in CIPO patients than that in healthy volunteers and IBS patients (17.1±11.0%, 73.0±9.3%, and 74.6±9.4%, respectively). No significant differences were observed in the contraction cycle. CONCLUSIONS: This study is the first to assess the clinical utility of cine-MRI in CIPO patients. Cine-MRI clearly detected contractility impairments in CIPO patients. Cine-MRI is noninvasive, radiation-free, and can directly evaluate the entire small bowel peristalsis, and can detect the affected loops at a glance; therefore, it might be extremely useful for the diagnosis and follow-up of CIPO patients in clinical practice.

Factors predicting the presence of small bowel lesions in patients with obscure gastrointestinal bleeding.

AIM: To identify the predictive factors for the presence of small bowel lesions in patients with obscure gastrointestinal bleeding (OGIB). METHODS: A total of 242 patients with OGIB (overt 149: occult 93) were retrospectively included in the present study. Capsule endoscopy (CE) was carried out to investigate the small bowel, and detected lesions were classified according to the P0-P2 system. Only P2 lesions were defined as significant lesions. Univariate and multivariate logistic regression analyses were carried out to define the predictive factors for the presence of small bowel lesions. RESULTS: In patients with overt OGIB, chronic kidney disease (CKD) ≥stage 4 (odds ratio [OR] 4.03; 95% confidence interval [CI] 1.45-11.1, P = 0.007) was identified as an independent predictor of the presence of vascular lesions, and a history of non-steroidalanti-inflammatory drug (NSAID) use as that of erosive/ulcerated lesions (OR 4.73; 95% CI 1.47-15.2, P = 0.009). However, in patients with occult OGIB, no significant predictors of the presence of vascular lesions were identified, whereas a history of low-dose aspirin (LDA) (OR 3.57; 95% CI 1.21-10.5, P = 0.02) and proton pump inhibitor (PPI) use (OR 3.18; 95% CI 1.02-9.92, P = 0.05) were identified as independent predictors of the presence of erosive/ulcerated lesions. CONCLUSIONS: Our results indicated that bleeding pattern and clinical characteristics could contribute to predicting the origin of OGIB.

[A case of HER2-positive gastric cancer successfully treated with trastuzumab plus capecitabine plus cisplatin chemotherapy as third-line treatment].

A 67-year-old woman was diagnosed as having advanced gastric cancer(poorly differentiated adenocarcinoma)with multiple liver metastases. She had received combined S-1 plus cisplatin chemotherapy as first-line treatment and weekly paclitaxel chemotherapy as second-line treatment, however, both had eventually proved ineffective. Because the gastric cancer was HER2-positive, she was treated with trastuzumab plus capecitabine plus cisplatin(XP)chemotherapy as third-line treatment. The primary lesion and liver metastatic lesions were confirmed to show remarkable regression. The ToGA trial revealed increased efficacy of trastuzumab in first-line treatment of cancers showing high expression levels of the HER2- protein. This case suggested the increased efficacy of trastuzumab in third-line treatment. Neutropenia and hand foot syndrome of grade 2 were all reported adverse events. She could receive trastuzumab plus XP chemotherapy safely by dose reduction or dormancy temporarily of capecitabine.

Metformin efficacy and safety for colorectal polyps: a double-blind randomized controlled trial.

BACKGROUND: Colorectal cancer is one of the major neoplasms and a leading cause of cancer death worldwide, and new preventive strategies are needed to lower the burden of this disease. Metformin, a biguanide, which is widely used for treating diabetes mellitus, has recently been suggestive to have a suppressive effect on tumorigenesis and cancer cell growth. In a previous study conducted in non-diabetic subjects, we showed that oral short-term low-dose metformin suppressed the development of colorectal aberrant crypt foci (ACF). ACF have been considered as a useful surrogate biomarker of CRC, although the biological significance of these lesions remains controversial. We devised a prospective randomized controlled trial to evaluate the chemopreventive effect of metformin against metachronous colorectal polyps and the safety of this drug in non-diabetic post-polypectomy patients. METHODS/DESIGN: This study is a multi-center, double-blind, placebo-controlled, randomized controlled trial to be conducted in non-diabetic patients with a recent history of undergoing colorectal polypectomy. All adult patients visiting the Yokohama City University hospital or affiliated hospitals for polypectomy shall be recruited for the study. Eligible patients will then be allocated randomly into either one of two groups: the metformin group and the placebo group. Patients in the metformin group shall receive oral metformin at 250 mg per day, and those in the placebo group shall receive an oral placebo tablet. At the end of 1 year of administration of metformin/placebo, colonoscopy will be performed to evaluate the polyp formation. DISCUSSION: This is the first study proposed to explore the effect of metformin against colorectal polyp formation. Metformin activates AMPK, which inhibits the mammalian target of rapamycin (mTOR) pathway. The mTOR pathway plays an important role in the cellular protein translational machinery and cell proliferation. Patients with type 2 diabetes taking under treatment with metformin have been reported to be at a lower risk of cancer development than those not taking under treatment with metformin. We showed in a previous study that metformin suppressed the formation of human colorectal ACF. We therefore decided to conduct a study to determine whether metformin might suppress the formation of human colorectal polyps. TRIAL REGISTRATION: This trial has been registered in the University hospital Medical Information Network (UMIN) Clinical Trials Registry as UMIN000006254.

Capsule endoscopy with flexible spectral imaging color enhancement reduces the bile pigment effect and improves the detectability of small bowel lesions.

BACKGROUND: Capsule endoscopy with flexible spectral imaging color enhancement (CE-FICE) has been reported to improve the visualization and detection of small-bowel lesions, however, its clinical usefulness is still not established. Therefore, we conducted a study to evaluate whether CE-FICE contributes to improve the detectability of small-bowel lesions by CE trainees. METHODS: Four gastroenterology trainees without prior CE experience were asked to read and interpret 12 CE videos. Each of the videos was read by conventional visualization method and under three different FICE settings. To evaluate whether the lesion recognition ability of the CE trainees could be improved by the FICE technology, the lesion detection rate under each of the three FICE settings was compared with that by conventional CE. CE trainees tend to miss small-bowel lesions in bile-pigment-positive condition, therefore we evaluated whether CE-FICE contributes to reducing the bile-pigment effect. The bile-pigment condition was determined by the color values around the small-bowel lesions according to the results of the receiver-operating-characteristic analysis. Moreover, we also evaluated whether poor bowel preparion might affect the accuracy of lesion recognition by CE-FICE. RESULTS: Of a total of 60 angioectasias, CE trainees identified 26 by conventional CE, 40 under FICE setting 1, 38 under FICE setting 2, and 31 under FICE setting 3. Of a total of 82 erosions/ulcerations, CE trainees identified 38 by conventional CE, 62 under FICE setting 1, 60 under FICE setting 2, and 20 under FICE setting 3. Compared with conventional CE, FICE settings 1 and 2 significantly improved the detectability of angioectasia (P = 0.0017 and P = 0.014, respectively) and erosions/ulcerations (P = 0.0012 and P = 0.0094, respectively). Although the detectability of small-bowel lesions by conventional CE (P = 0.020) and under FICE setting 2 (P = 0.0023) was reduced by the presence of bile-pigments, that under FICE setting 1 was not affected (P = 0.59). Our results also revealed that in poor bowel visibility conditions, CE-FICE yielded a high rate of false-positive findings. CONCLUSIONS: CE-FICE may reduce the bile-pigment effect and improve the detectability of small-bowel lesions by CE trainees; the reliability of CE-FICE may be improved by good bowel preparation.

Single-agent gemcitabine in elderly patients with unresectable biliary tract cancer.

BACKGROUND/AIMS: This study examined the effect of systemic chemotherapy with gemcitabine (GEM) on survival in elderly patients (aged > or = 70 years) with unresectable biliary tract cancer as compared with best supportive care (BSC). METHODOLOGY: We conducted a retrospective study of consecutive patients with unresectable biliary tract cancer administered GEM (800-1,000 mg/m2) on days 1, 8 and 15 every 4 weeks as a first-line treatment. Eligibility included age 70 years and over, and bile duct carcinoma or gallbladder cancer. RESULTS: Twenty-eight patients were enrolled: 13 (46.4%) received chemotherapy with GEM and 15 (53.6%) received BSC. No cases of complete or partial response were observed. Stable and progressive disease was observed in 9 (69.2%) and 2 patients (15.4%), respectively. Disease control rate was 69.2%. The median overall survival time of patients treated with GEM and BSC was 9.1 and 2.9 months, and the 1-year survival rates were 15.4% and 6.7%, respectively. Grade 3/4 neutropenia occurred in three (23.1%), leukopenia in two (15.4%) and anemia in one patient (7.7%). Grade 3 non-hematologic toxicities were constipation (7.7%) and fatigue (7.7%). CONCLUSIONS: Chemotherapy with single-agent GEM is a safe and well tolerated regimen for elderly patients with unresectable biliary tract cancer.

Single-agent gemcitabine in elderly patients with unresectable biliary tract cancer.

BACKGROUND/AIMS: This study examines the effect of systemic chemotherapy with gemcitabine (GEM) on survival in elderly patients (aged > or =70 years) with unresectable biliary tract cancer and compares it with best supportive care (BSC). METHODOLOGY: We conducted a retrospective study of consecutive patients aged > or =70 years, with unresectable biliary tract cancer who were administered GEM (800-1000 mg/m2) on days 1, 8, and 15 every 4 weeks as a first-line treatment. RESULTS: Twenty-eight patients were enrolled: 13 (46.4%) received chemotherapy with GEM and 15 (53.6%) received BSC. No cases of complete or partial response were observed. Stable disease was observed in 9 patients (69.2%) and progressive disease in 2 patients (15.4%). Disease control rate was 69.2%. The median overall survival time of patients treated with GEM and BSC was 9.1 and 2.9 months, and the 1-year survival rates were 15.4% and 6.7% respectively. Grade 3/4 neutropenia occurred in three patients (23.1%), leukopenia in two patients (15.4%) and anemia in one patient (7.7%). Grade 3 non-hematologic toxicities were constipation (7.7%) and fatigue (7.7%). CONCLUSIONS: Chemotherapy with single-agent GEM is a safe and well tolerated regimen for elderly patients with unresectable biliary tract cancer.

Incidence of and risk factors for upper gastrointestinal complications in patients taking low-dose aspirin in Japan.

BACKGROUND/AIMS: Low-dose aspirin is widely used for the prevention of cardiovascular and cerebrovascular diseases. However, administration of low-dose aspirin is associated with an increased risk of upper gastrointestinal complications, such as upper gastrointestinal erosions, ulcers and bleeding. The aim of this study was to clarify the prevalence and various clinical factors of upper gastrointestinal complications associated with low-dose aspirin treatment. METHODOLOGY: A total of 1213 patients taking low-dose aspirin were evaluated with upper endoscopic examinations. We studied retrospectively the incidence of and risk factors for upper gastrointestinal complications associated with low-dose aspirin use. RESULTS: Of the 1213 patients taking low-dose aspirin, 598 patients and 72 patients were found to have gastroduodenal erosions (57.3%) and peptic ulcers (5.9%), respectively. Of these 72 peptic ulcers, 27 were diagnosed as hemorrhagic ulcers. Previous ulcer history was identified as a risk factor for peptic ulcer and upper gastrointestinal bleeding during low-dose aspirin therapy. Upper gastrointestinal symptoms and no use of gastroprotective agents were also identified as risk factors for peptic ulcers. In this study, the use of a histamine-2 receptor antagonist was indicated as a protective factor for peptic ulcers. CONCLUSIONS: Low-dose aspirin therapy is associated with an increased risk of developing upper gastrointestinal complications. Administration of a histamine-2 receptor antagonist was effective for the prevention of low-dose aspirin induced peptic ulcers.

Crystallization and preliminary X-ray diffraction studies of maleylacetate reductase from Rhizobium sp. strain MTP-10005.

Maleylacetate reductase (EC 1.3.1.32), which catalyzes the reduction of maleylacetate to 3-oxoadipate, plays an important role in the aerobic microbial catabolism of resorcinol. The enzyme has been crystallized at 293 K by the sitting-drop vapour-diffusion method supplemented with a microseeding technique, using ammonium sulfate as the precipitating agent. The crystal belonged to the monoclinic space group C2, with unit-cell parameters a = 56.85, b = 121.13, c = 94.09 A, beta = 101.48 degrees , and contained one dimeric molecule in the asymmetric unit. It diffracted to 1.79 A resolution.

Crystallization and preliminary X-ray diffraction studies of tetrameric malate dehydrogenase from the novel Antarctic psychrophile Flavobacterium frigidimaris KUC-1.

Flavobacterium frigidimaris KUC-1 is a novel psychrotolerant bacterium isolated from Antarctic seawater. Malate dehydrogenase (MDH) is an essential metabolic enzyme in the citric acid cycle and has been cloned, overexpressed and purified from F. frigidimaris KUC-1. In contrast to the already known dimeric form of MDH from the psychrophile Aquaspirillium arcticum, F. frigidimaris MDH exists as a tetramer. It was crystallized at 288 K by the hanging-drop vapour-diffusion method using ammonium sulfate as the precipitating agent. The crystal diffracted to a maximum resolution of 1.80 A. It contains one tetrameric molecule in the asymmetric unit.

Oral esomeprazole vs injectable omeprazole for the prevention of hemorrhage after endoscopic submucosal dissection.

AIM: To evaluate the effectiveness of oral esomeprazole (EPZ) vs injectable omeprazole (OPZ) therapy to prevent hemorrhage after endoscopic submucosal dissection (ESD). METHODS: A case-control study was conducted using a quasi-randomized analysis with propensity score matching. A total of 258 patients were enrolled in this study. Patients were treated with either oral EPZ or injectable OPZ. The endpoint was the incidence of hemorrhage after ESD. RESULTS: Data of 71 subjects treated with oral EPZ and 172 subjects treated with injectable OPZ were analyzed. Analysis of 65 matched samples revealed no difference in the incidence of hemorrhage after ESD between the oral EPZ and injectable OPZ groups (OR = 0.89, 95%CI: 0.35-2.27, P ≥ 0.99). CONCLUSION: We conclude that oral EPZ therapy is a useful alternative to injectable PPI therapy for the prevention of hemorrhage after ESD.

Is a fecal occult blood test a useful tool for judging whether to perform capsule endoscopy in low-dose aspirin users with negative colonoscopy and esophagogastroduodenoscopy?

BACKGROUND: Aspirin use is reportedly not to be associated with fecal immunochemical occult blood test (FIT) false-positive results for the detection of colorectal cancer. The need for additional small bowel exploration in FIT-positive, low-dose aspirin users with a negative colonoscopy is controversial. The aim of this study was to assess the ability of FIT to judge whether capsule endoscopy (CE) should be performed in low-dose aspirin users with negative colonoscopy and esophagogastroduodenoscopy findings by comparing FIT results with CE findings. METHODS: A total of 264 consecutive low-dose aspirin users with negative colonoscopy and esophagogastroduodenoscopy who were scheduled to undergo CE at five hospitals in Japan were enrolled. Patients had been offered FIT prior to the CE. The association between the FIT results and the CE findings was then assessed. RESULTS: One hundred and fifty-seven patients were included in the final analysis. Eighty-four patients (53.5 %) had positive FIT results. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of positive FIT results for small bowel ulcers were 0.56, 0.47, 0.30, and 0.73, respectively. Furthermore, the NPV of positive FIT results for severe small bowel injury (Lewis score ≥790) was markedly high (0.90). When the analysis was performed only in low-dose aspirin users with anemia, the sensitivity of the positive FIT results was notably improved (0.72). CONCLUSIONS: Small bowel evaluation using CE is not recommended for FIT-negative, low-dose aspirin users. However, small bowel evaluation using CE should be considered in both FIT-positive and anemic low-dose aspirin users.

Structure of the carboxypeptidase Y inhibitor IC in complex with the cognate proteinase reveals a novel mode of the proteinase-protein inhibitor interaction.

Carboxypeptidase Y (CPY) inhibitor, IC, shows no homology to any other known proteinase inhibitors and rather belongs to the phosphatidylethanolamine-binding protein (PEBP) family. We report here on the crystal structure of the IC-CPY complex at 2.7 A resolution. The structure of IC in the complex with CPY consists of one major beta-type domain and a N-terminal helical segment. The structure of the complex contains two binding sites of IC toward CPY, the N-terminal inhibitory reactive site (the primary CPY-binding site) and the secondary CPY-binding site, which interact with the S1 substrate-binding site of CPY and the hydrophobic surface flanked by the active site of the enzyme, respectively. It was also revealed that IC had the ligand-binding site, which is conserved among PEBPs and the putative binding site of the polar head group of phospholipid. The complex structure and analyses of IC mutants for inhibitory activity and the binding to CPY demonstrate that the N-terminal inhibitory reactive site is essential both for inhibitory function and the complex formation with CPY and that the binding of IC to CPY constitutes a novel mode of the proteinase-protein inhibitor interaction. The unique binding mode of IC toward the cognate proteinase provides insights into the inhibitory mechanism of PEBPs toward serine proteinases and into the specific biological functions of IC belonging to the PEBP family as well.

Crystal structure of thermostable aspartase from Bacillus sp. YM55-1: structure-based exploration of functional sites in the aspartase family.

The crystal structure of the thermostable aspartase from Bacillus sp. YM55-1 has been solved and refined for 2.5A resolution data with an R-factor of 22.1%. The present enzyme is a homotetramer with subunits composed of three domains. It exhibits no allosteric effects, in contrast to the Escherichia coli aspartase, which is activated by divalent metal cation and L-aspartate, but is four-times more active than the E.coli enzyme. The overall folding of the present enzyme subunit is similar to those of the E.coli aspartase and the E.coli fumarase C, both of which belong to the same superfamily as the present enzyme. A local structural comparison of these three enzymes revealed seven structurally different regions. Five of the regions were located around putative functional sites, suggesting the involvement of these regions into the functions characteristic of the enzymes. Of these regions, the region of Gln96-Gly100 is proposed as a part of the recognition site of the alpha-amino group in L-aspartate for aspartase and the hydroxyl group in L-malate for fumarase. The region of Gln315-Gly323 is a flexible loop with a well-conserved sequence that is suggested to be involved in the catalytic reaction. The region of Lys123-Lys128 corresponds to a part of the putative activator-binding site in the E.coli fumarase C. The region in the Bacillus aspartase, however, adopts a main-chain conformation that prevents the activator binding. The regions of Gly228-Glu241 and Val265-Asp272, which form a part of the active-site wall, are suggested to be involved in the allosteric activation of the E.coli aspartase by the binding of the metal ion and the activator. Moreover, an increase in the numbers of intersubunit hydrogen bonds and salt-bridges is observed in the Bacillus aspartase relative to those of the E.coli enzyme, implying a contribution to the thermostability of the present aspartase.