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Y Niwa

Publications and source records attributed to Y Niwa.

At least 19 recordsLinked to original sources
PubMed2006

Pit patterns in rectal mucosa assessed by magnifying colonoscope are predictive of relapse in patients with quiescent ulcerative colitis.

BACKGROUND: Relapse of ulcerative colitis is difficult to predict by routine colonoscopy. A high-resolution video-magnifying colonoscope with chromoscopy enables the observation of colorectal mucosal pit patterns. AIMS: To investigate the association of pit patterns as assessed by magnifying colonoscopy (MCS) with histological inflammation and mucosal chemokine activity in patients with quiescent ulcerative colitis, and to prospectively analyse the prognostic factors that may predict exacerbations. METHODS: MCS was performed in 113 patients with ulcerative colitis in remission. Pit patterns in the rectal mucosa were classified into four MCS grades on the basis of size, shape and arrangement. Mucosal interleukin (IL) 8 activity was measured in biopsy specimens of rectal mucosa and the specimens were assessed for histological disease activity. The patients were then followed until relapse or for a maximum of 12 months. Multivariate survival analysis was carried out to determine the independent predictors of clinical relapse. RESULTS: A positive correlation was identified between MCS grade, histological grade (p = 0.001) and mucosal IL8 activity (p<0.001). Multivariate proportional hazard model analysis showed that MCS grade was a significant predictor of relapse (relative risk 2.06, p = 0.001). Kaplan-Meier estimate of relapse during 12 months of follow-up was found to increase with increasing MCS grade, with values of 0% for grade 1, 21% for grade 2, 43% for grade 3 and 60% for grade 4. CONCLUSION: MCS grading is associated with the degree of histological inflammation and mucosal IL8 activity in patients with quiescent ulcerative colitis, and may predict the probability of subsequent disease relapse in patients with ulcerative colitis in remission.

Adolescent↗
PubMed2006

DNA hypermethylation in colorectal neoplasms and inflammatory bowel disease: a mini review.

DNA hypermethylation is one of major epigenetic changes. Hypermethylation of many genes has been reported to be related with carcinogenesis and tumor progression of colorectal cancer. Some genes including estrogen receptor is associated with ageing, and changes related with ageing may be accelerated in inflammatory bowel disease. Furthermore, fecal DNA methylation will be able to be used as a marker of colorectal cancer and inflammatory bowel disease. Evaluation of hypermethylation potentially contributes diagnosis of colorectal diseases.

Animals↗
PubMed2006

Preliminary comparison of capsule endoscopy and double-balloon enteroscopy in patients with suspected small-bowel bleeding.

BACKGROUND AND STUDY AIMS: Capsule endoscopy (CE) and double-balloon enteroscopy (DBE) have been introduced as modalities for examining the entire small bowel. The aim of the present study was to assess the clinical effects of CE and DBE to consider the roles of CE and DBE and the indications for the procedures in patients with suspected small-bowel bleeding. PATIENTS AND METHODS: Between June 2004 and January 2005, 32 patients in whom a site of bleeding in the gastrointestinal tract had not been identified were enrolled in the study. Twenty-eight patients were examined with both methods. Bleeding sources were categorized as either A1 lesions (immediate hemostatic procedures required) or A2 lesions (close observation required). CE and DBE were evaluated with regard to whether or not they were capable of accessing the entire small bowel and provided a diagnosis, and the access and diagnostic rates were calculated. RESULTS: On CE, 13 patients were diagnosed with A1 lesions and six with A2 lesions; on DBE, 11 had A1 lesions and one had an A2 lesion. The access rate for the entire small intestine on CE was 90.6 % (29 of 32), significantly higher than with DBE at 62.5 % (10 of 16; P < 0.05). The diagnostic rate on CE was 59.4 % (19 of 32), higher than with DBE at 42.9 % (12 of 28; P = 0.30), but not significantly different. Among patients with A1 lesions who were diagnosed with DBE, histological diagnoses were obtained in six of the 11, and three patients were treated. CONCLUSIONS: In many suspected small-bowel bleeding cases, CE should be selected for the initial diagnosis and DBE for treatment or histopathological diagnosis after detection of the bleeding site on CE.

Adult↗
PubMed2006

Confocal endomicroscopy for the diagnosis of gastric cancer in vivo.

BACKGROUND AND STUDY AIMS: Advances in endoscopy have led to imaging of the details of the gastric mucosa, but the histological diagnosis usually has to be confirmed by endoscopic biopsy. A method of confocal endomicroscopy that has recently been developed allows the observation of living cells in vivo. Several investigators have reported that the technique is of value, but there have as yet been no studies describing its application in gastric cancer. PATIENTS AND METHODS: Twenty-seven patients with early gastric cancer underwent confocal endomicroscopy (Pentax EG-3870CIK; Pentax, Tokyo, Japan). After intravenous administration of fluorescein sodium, confocal images obtained from the normal mucosa and from cancerous lesions were interpreted by two pathologists independently and compared with the histological findings, including CD34 immunostaining of biopsy specimens or resected specimens from the same sites. RESULTS: Fluorescein yielded high-quality confocal images of the gastric mucosa; if cancer could be targeted (59%) images were mostly graded good. The images corresponded to the hematoxylin-eosin staining of transverse sections of specimens from the same sites. In the results for the interpretation by the two pathologists, the accuracy for the diagnosis of gastric cancer was 94.2% (pathologist A), and 96.2% (pathologist B), respectively. The accuracy decreased substantially when poor images and inaccessible lesions were included. CONCLUSIONS: Confocal endomicroscopy is useful in the diagnosis of gastric cancer but good quality images cannot always be obtained. In the future, it may allow virtual biopsy and help reduce unnecessary biopsies.

Adenocarcinoma↗
PubMed2005

Temporal changes in postural sway caused by ultrashort-acting hypnotics: triazolam and zolpidem.

Two ultrashort-acting hypnotics, triazolam 0.25 mg and zolpidem 10 mg, were studied for their effects on equilibrium function in humans. Eight healthy male subjects participated in a double-blind, placebo-controlled study after informed consent. They subjected to static equilibrium tests, oculomotor tests and an assay of drug concentrations in the blood. Zolpidem was statistically significant in postural sway in tandem stance test, as defined by parametric values of tracing sum length and polygonal area of foot pressure center measured by a gait analysis system. In the tandem stance test, triazolam was statistically significant in postural sway only as defined by the polygonal area. However, in the Romberg test, the only statistically significant difference in zolpidem use was observed in polygonal area values. Blood concentrations of triazolam and zolpidem were found to closely correlate with the extent of postural sway in both tandem stance and Romberg tests. In this study, zolpidem with minimal muscle-relaxant effect incurred imbalance more extensively than triazolam, which is known for its effect of muscle relaxation. In addition, gaze deviation nystagmus was observed only in zolpidem use in 5 of 8 subjects (62.5%). From these results, it is suggested that in the use of hypnotics, sway derives from the suppression of the central nervous system relevant to awakening rather than from muscle relaxation. The prior reference to blood concentrations of hypnotics should help improve safety care in minimizing loss of balance control and possible fall.

Accidental Falls↗
PubMed2005

The use of endoscopic ultrasound-guided fine-needle aspiration for investigation of submucosal and extrinsic masses of the colon and rectum.

BACKGROUND AND STUDY AIM: Ensdoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been reported as a useful technique for histological diagnosis of submucosal or extrinsic gastrointestinal and pancreatic lesions. The aim of this study was to evaluate the use of EUS-FNA for the diagnosis of lesions either within or adjacent to the wall of the colon and rectum. PATIENTS AND METHODS: A total of 22 patients with a lesion within the wall of, or adjacent to, the colon or rectum underwent EUS-FNA. They were divided into two groups: patients who had previously had a malignancy (the "previous +ve" group, n = 11), and patients who had not previously had a malignancy (the "previous -ve" group, n = 11). In the four patients who had lesions located proximal to the sigmoid colon, EUS-FNA was performed using a guide wire and overtube. The success rates for adequate tissue sampling and for detecting malignant and benign masses by EUS-FNA were evaluated and the success rate for detection was compared with the success rate of EUS and computed tomography. RESULTS: Sufficient tissue for evaluation was obtained from 21 of the 22 patients (95.5 %). The overall rate of detection of malignant and benign masses was 95.5 % (21/22) for EUS-FNA and 81.8 % (18/22) for pre-EUS-FNA imaging investigations. Of the 11 patients in the previous +ve group, ten were diagnosed with recurrences of primary malignancies; of the 11 patients in the previous -ve group, four were diagnosed with primary malignancies and seven were diagnosed with benign lesions. There were no complications related to the EUS-FNA procedure. CONCLUSIONS: EUS-FNA is a safe technique which is useful in the planning of treatment for patients who have a mass within the wall or adjacent to the wall of the entire length of the colon or rectum.

Adult↗
PubMed2005

Quantitative analysis of the microvascular architecture observed on magnification endoscopy in cancerous and benign gastric lesions.

BACKGROUND AND STUDY AIMS: Gastric cancer remains a common malignant tumor in Japan. The aim of this study was to attempt a quantitative evaluation of the microvascular architecture observed by magnification endoscopy using image analysis, and to investigate whether this method is able to distinguish between gastric cancers and benign lesions. PATIENTS AND METHODS: A total of 132 patients were studied using magnification endoscopy, and image analysis was performed in 71 patients (32 patients with early gastric cancer, 39 patients with benign lesions). Analysis was not possible in the other 61 patients because the quality of the image was not good enough. A square region of interest was selected from the magnified images of the gastric mucosa. From this we extracted the vascular images corresponding to microvessels and calculated the mean caliber of vessels in the region of interest. RESULTS: Image analysis provided good-quality images of microvessels and enabled evaluation of the microvascular architecture. The mean caliber of vessels was 4.454 pixels in 17 differentiated adenocarcinomas, 4.319 pixels in 15 undifferentiated adenocarcinomas, and 4.034 pixels in the 39 benign lesions. This represented a significant difference between gastric cancers and benign lesions (P<0.0001). Histopathological investigation of surgically resected tumors demonstrated the mean caliber of microvessels in cancerous lesions to be greater than that of microvessels in the surrounding mucosa. CONCLUSIONS: Image analysis was useful for evaluating the microvascular architecture of the gastric mucosa, and calculation of the mean caliber of the vessels may prove helpful in the differential diagnosis of gastric cancers. However, analysis was not possible in 61 of the 132 patients studied because of inadequate image quality, and this represents a significant limitation of this diagnostic method.

Adult↗
PubMed2005

Effects of edaravone on human neutrophil function.

BACKGROUND: Neutrophils play a crucial role in the antibacterial host defence system. Edaravone is used in critically ill patients who are often immuno-compromised secondary to concomitant disease or immunosuppressive therapy. The aim of the current study was to assess the effect of edaravone, a novel free-radical scavenger, on several aspects of human neutrophil function using an in vitro system. METHODS: Chemotaxis, phagocytosis, reactive oxygen species (ROS) production by neutrophil (cellular) and xanthine-xanthine oxidase (acellular) systems, and intracellular calcium ion levels ([Ca(2 +) ]i) were measured in the absence and in the presence (at a clinically relevant concentration, and 0.1-fold, and 10-fold this concentration) of edaravone. RESULTS: The clinically relevant concentration of edaravone did not inhibit chemotxais, phagocytosis, or superoxide production of neutrophils. Even at its ordinary clinical plasma concentration, the drug inhibited hydrogen peroxide (H(2)O(2)) and hydroxyl radical (OH*) generation in the cellular (neutrophil) as well as in the cell-free (xanthine-xanthine oxidase) system (P < 0.05). Edaravone did not affect elevation of [Ca(2 +) ]i in neutrophils stimulated by a chemotactic factor. CONCLUSIONS: These findings suggest that edaravone quenched H(2)O(2), and OH* generated rather than impaired the ability of neutrophils to produce the ROS. However, further studies using in vivo systems are required to elucidate the effects of edaravone on neutrophil function in clinical settings.

Antipyrine↗
PubMed2004

Usefulness of magnifying endoscopy in the diagnosis of early gastric cancer.

BACKGROUND AND STUDY AIMS: We investigated the characteristic findings of early gastric cancer revealed by magnifying endoscopy, and clarified their relationship with histopathological features. PATIENTS AND METHODS: A total of 74 patients with early gastric cancer underwent magnifying endoscopy ( x 80) between March 2000 and December 2001. The endoscopic findings demonstrated 11 elevated-type carcinomas and 63 depressed-type, and histological examination showed 56 differentiated carcinomas and 18 undifferentiated carcinomas. The histopathological results were compared with findings from magnifying endoscopy regarding minute surface structure and microvessels. RESULTS: We were able to roughly classify the minute surface structure of early gastric cancer as shown by magnifying endoscopy into three patterns, as follows: (i). a small regular pattern of sulci and ridges; (ii). an irregular pattern of sulci and ridges; and (iii). a lack of visible structure. Abnormal microvessels observed in cancerous lesions were classified according to two patterns: irregular minute vessels and variation of vessel caliber. The small regular pattern of sulci and ridges was significantly more frequently observed in differentiated carcinoma (30/56, 53.6 %) than in undifferentiated carcinoma (2/18, 11.1 %). Lack of visible structure and irregular minute vessels were significantly more frequently observed in undifferentiated carcinoma (44.4 % and 77.7 %) than in differentiated carcinomas (5.4 % and 51.8 %). CONCLUSION: The minute surface structure and microvessels observed by magnifying endoscopy were related to histopathological findings. Magnifying endoscopy is valuable for predicting the histological nature in the diagnosis of early gastric cancer.

Adenocarcinoma↗
PubMed2004

Pilot study of pancreatoscopic lithotripsy using a 5-fr instrument: selected patients may benefit.

BACKGROUND AND STUDY AIMS: Despite advances in endoscopic procedures and extracorporeal shock wave lithotripsy (ESWL), the removal of impacted pancreatic duct stones demands a certain amount of time. The aim of this study was to determine which patient group might suitable for our single-session treatment. PATIENTS AND METHODS: The study included 17 patients who were symptomatic due to relapsing pancreatitis with pancreatic duct stones. A 5-Fr miniscope was inserted via the papilla to the impacted pancreatic duct stone and pancreatoscopic laser lithotripsy (PSLL) was performed, under direct vision, in only one session. If complete extraction of the pancreatic duct stones was not achieved with PSLL, ESWL was adopted in subsequent sessions. RESULTS: Complete extraction of the pancreatic duct stones using PSLL in a single session was achieved in eight of 17 patients. Single-session PSLL was only suitable for patients with pancreatic duct stones smaller than 17 mm in diameter and with no severe stricture or sharp bend in the pancreatic duct proximal to the stones. CONCLUSIONS: Our single-session endoscopic treatment of pancreatic duct stones was useful in a selected patient group.

Adult↗
PubMed2003

Effects of ropivacaine on human neutrophil function: comparison with bupivacaine and lidocaine.

BACKGROUND AND OBJECTIVE: Neutrophils are important both for the immunological defence system and for the inflammatory tissue autoinjury mechanism. However, many local anaesthetics impair certain neutrophil functions. The aim was to assess the effects of ropivacaine, bupivacaine and lidocaine on human neutrophils from adult volunteers. METHODS: Chemotaxis, phagocytosis, reactive oxygen species production, intracellular calcium ion ([Ca2+]i) concentrations and protein kinase C activity were measured in the absence and presence of ropivacaine, bupivacaine or lidocaine. The lowest concentrations of the local anaesthetics were similar to those clinically observed in the plasma. RESULTS: Bupivacaine did not affect any neutrophil function (P > 0.05). Ropivacaine failed to change chemotaxis or phagocytosis, while lidocaine suppressed both these neutrophil functions. Ropivacaine (15, 150 microg mL(-1)) and lidocaine (20, 200 microg mL(-1)) impaired neutrophil production of O2-, H2O2 and OH- (P < 0.05) at similar rates (by 7-10%). These same concentrations of ropivacaine and lidocaine suppressed [Ca2+1i elevation. Finally, neither ropivacaine nor bupivacaine inhibited protein kinase C activity, while lidocaine did. CONCLUSIONS: Suppression of the [Ca2+]i response in neutrophils by ropivacaine may represent one of the mechanisms responsible for the impairment of neutrophil functions. It should be emphasized that the inhibitory effects of ropivacaine are minor and are attained only at high concentrations, which may minimize the clinical implication of ropivacaine-associated impairment of reactive oxygen species production. Further studies using in vivo systems are required to identify the inhibitory effects of ropivacaine on reactive oxygen species production in clinical settings.

Adult↗
PubMed2003

Protein oxidative damage in the stratum corneum: Evidence for a link between environmental oxidants and the changing prevalence and nature of atopic dermatitis in Japan.

BACKGROUND: The incidence of atopic dermatitis (AD) has increased in Japan, along with the number of patients with severe and treatment-resistant AD in urban and industrial areas. We hypothesize that these changes could be due to increased reactive oxygen species (ROS) generated from environmental pollution and solar radiation. OBJECTIVES: To demonstrate whether direct oxidative protein damage of the stratum corneum of the biopsied skin from AD patients is increased when compared with controls. PATIENTS AND METHODS: Carbonyl moieties in skin biopsies from 75 patients with AD were assessed using both spectrophotometric and immunohistochemical detection of the formation of dinitrophenylhydrazone (DNP) from dinitrophenylhydrazine (DNPH). These were compared with diseased and normal controls. Lipid peroxidation was also assessed by staining with antibody to 4-hydroxy-2-nonenal (4-HNE), an aldehyde product of oxidized omega-6-fatty acids. In addition, the activity of superoxide dismutase (SOD), an effective scavenger of ROS, was assessed and compared with controls. RESULTS: The level of protein carbonyl moieties in patients' skin was elevated and correlated directly with the severity of the disease. In contrast, DNP formation was not significantly increased in diseased controls, when compared with healthy volunteers, and no statistical significance was found between the two control groups. SOD activity was increased except for those with extra-severe disease. Positive staining with anti-DNP antibody and anti-4-HNE antibody were found in the most superficial layers of the stratum corneum. CONCLUSIONS: This study has found an association between AD severity and markers of ROS-associated damage, adding weight to the hypothesis that environmentally generated ROS may induce oxidative protein damage in the stratum corneum, leading to the disruption of barrier function and exacerbation of AD.

Adult↗
PubMed2003

Topical application of the immunosuppressant tacrolimus accelerates carcinogenesis in mouse skin.

BACKGROUND: Tacrolimus, produced by the fungus Streptomyces tsukabaensis, is a potent macrolide immunosuppressant widely used in liver and kidney transplantation. Topical tacrolimus has recently been found to be an effective treatment for atopic dermatitis (AD). OBJECTIVES: Because of the well-known association between T-cell immunosuppression and an increased risk of carcinogenesis, we investigated the effect of topical tacrolimus on skin carcinogenesis in 117 mice. METHODS: Approximately 8 cm2 of the shaved dorsal skin of 7-week-old female CD-1 mice was treated with 7,12-dimethylbenz[alpha]anthracene (DMBA) dissolved in acetone, which is in general use as a tumour initiator, or acetone alone, on day 1 of the experiment, followed by promoting treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) with or without tacrolimus, or acetone with or without tacrolimus, for 20 weeks. The mice were divided into six treatment groups: (1) DMBA followed by acetone; (2) DMBA followed by TPA; (3) DMBA followed by acetone + tacrolimus; (4) DMBA followed by TPA + tacrolimus; (5) acetone followed by acetone + tacrolimus; and (6) acetone followed by acetone (control). RESULTS: The induction of skin tumours was significantly greater in the TPA-treated groups than in the absence of TPA. However, after 14 weeks there was marked synergy between tacrolimus and the DMBA/TPA regimen, with 0.47 +/- 0.13 (mean +/- SD) new tumours per mouse per week in group 4 vs. 0.10 +/- 0.025 in group 2 (P < 0.01), and 0.01 +/- 0.002 in group 3. A significant reduction in the CD4/CD8 ratio was found in axillary and inguinal lymph nodes in tacrolimus-treated mice, supporting the presumption that the immunosuppressive effect of the drug was responsible for its effect in promoting tumorigenesis. The major increase in tumours caused by topical tacrolimus was of papillomas, not squamous cell carcinomas. Papillomas are uncommon in humans, and are benign. However, 8.5% of the tumours found in the experiment were squamous cell carcinomas, and a considerable synergy between topical tacrolimus and conventional carcinogens was observed, raising the spectre of some risk of skin carcinogenesis in AD patients undergoing prolonged treatment with tacrolimus. CONCLUSIONS: Caution and careful surveillance are required with regard to skin lesions in patients treated with tacrolimus for prolonged periods.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2003

Associations between tumor diameter and prognostic variables of epithelial ovarian cancer.

PURPOSE: Associations of tumor diameter in epithelial ovarian cancer with clinical and pathological prognostic variables were investigated. METHODS: The clinical and pathological records of 233 patients diagnosed with epithelial ovarian cancer and treated at Aichi Cancer Center were studied. RESULTS: Tumor diameters of 44 patients (18.9%) were < 5 cm, 90 (38.6%) were 5-10 cm, and 99 (42.5%) were > 10 cm. While 90.9% (40/44) of < 5 cm tumors presented with FIGO stage III-IV, 40.4% (40/99) of > 10 cm tumors were advanced. Intra-abdominal disease was also significantly associated with tumor diameter, although differences among lymph-node status were not significant. The incidence of serous and endometrioid adenocarcinoma in < 5 cm tumors were 75.0% (33/44) and 11.4% (5/44), respectively, while those of > 10 cm tumor were 32.3% (32/99) and 17.2% (17/99). Multivariate analysis revealed that tumor diameter was not an independent prognostic variable. CONCLUSION: Tumor diameter of ovarian cancer is associated closely with histological subtypes and stage of disease, especially intra-abdominal disease.

Aged↗
PubMed2002

Simultaneous multiple early cancers of esophagus and stomach treated by endoscopic mucosal resection.

Endoscopic mucosal resection (EMR) has been accepted as a completely curative treatment of gastrointestinal mucosal cancers. With advances in diagnostic techniques, the tendency to detect simultaneous multiple primary cancers is increasing. Patients with another cancer coexisting with esophageal cancer have had a poor prognosis, but if both cancers are detected in the early stage, complete treatment consisting only of endoscopic surgery, with a good prognosis, is expected. We describe two cases of simultaneous multiple early cancers of the stomach and esophagus, treated by EMR.

Adenocarcinoma↗