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排序方式: 共有628条查询结果,搜索用时 15 毫秒
1.
Yasushi Tohi Takashi Nakano Haruyuki Makio Shigekazu Matsui Terunori Fujita Tsutomu Yamaguchi 《Macromolecular chemistry and physics.》2004,205(9):1179-1186
Summary: Bis(phenoxy‐imine) Zr complexes with MAO activation can produce polyethylenes with well‐defined bimodal molecular weight distributions. Polymerization behavior indicates that minor changes in the ligand structures can have a significant effect on the modality of the resulting polyethylenes. Although there is no direct relationship between the bimodal catalytic behavior and the structure of a precatalyst complex in solution, a precatalyst complex having a methyl or methoxy group para to the phenoxy‐oxygen inclined to exhibit bimodal behavior whereas that with a pentafluorophenyl group on the imine‐nitrogen displayed unimodal behavior. Polymerization results suggest that bimodal behavior is linked to the presence of two kinds of cationic active species, which arise from different modes of ligand coordination. A qualitative correlation was found between the calculated amounts of possible cationic active species and the uni‐ and bimodal catalytic behavior. Based on the results obtained, we concluded that the bimodal polyethylenes are produced by two kinds of cationic active species having two available cis‐located sites with cis‐N, trans‐O and cis‐N, cis‐O arrangements. The results introduced herein are rare examples of the production of well‐defined bimodal polyethylenes using a single precatalyst.
2.
Atsuo Murata Hitoshi Toda Ken -Ichi Uda Hirohito Hayashida Takeshi Kato Hidewaki Nakagawa Shigekazu Yokoyama Hideaki Morishita Toru Yamakawa Jiro Hirose Takesada Mori Nariaki Matsuura 《Inflammation》1994,18(4):337-347
Severe inflammatory responses after major surgeries, trauma, and infection develop multiple organ dysfunction. In the mechanisms of the pathogenesis of these responses, activated neutrophils are thought to be important in terms of their ability to produce various kinds of proteinases, which can degrade various proteins constructing human tissues. Among their proteinases, neutrophil elastase is the strongest serine proteinase secreted from activated neutrophils. Thus, we examined in this study the inhibitory effect and therapeutic efficacy of newly produced recombinant human Kunitz-type proteinase inhibitor (R-020), which coded the second domain of human urinary trypsin inhibitor. R-020 was effective in significantly improving the survival rate after induction of the rat lethal peritonitis model (cecal ligation and punctureinduced septic shock model). We suggest that various serine proteinases are implicated in the pathogenesis of neutrophil-related multiple organ failure and that recombinant human Kunitz-type proteinase inhibitor might be effective in the treatment of these kinds of organ dysfunction. 相似文献
3.
Lethal anemia caused by interferon-beta produced in mouse embryos carrying undigested DNA 总被引:1,自引:0,他引:1
The livers of DNase II-deficient mouse embryos contain many macrophages carrying undigested DNA, and the embryos die in utero. Here we report that erythroid precursor cells underwent apoptosis in the livers of DNase II-deficient embryos and that in the liver, interferon-beta mRNA was expressed by the resident macrophages. When the DNase II-deficient mice were crossed with mice deficient in type I interferon receptor, the resultant 'double-mutant' mice were born healthy. The double-mutant embryos expressed interferon-beta mRNA, but the expression of a subset of the interferon-responsive genes dysregulated in DNase II-deficient embryos was restored to normal. These results indicate that the inability to degrade DNA derived from erythroid precursors results in interferon-beta production that induces expression of a specific set of interferon-responsive genes associated with embryonic lethality in DNase II-deficient mice. 相似文献
4.
Sinuhe Hahn Thomas Stalder Marion Wernli Diana Bürgin Jürg Tschopp Shigekazu Nagata Peter Erb 《European journal of immunology》1995,25(9):2679-2685
Fas was recently demonstrated to be the major target molecule engaged by CD4+ cytolytic T lymphocytes (CTL). We examined Fas expression on various cloned T cell subpopulations and their susceptibility to lysis by CD4+ or CD8+ CTL. A reciprocal relationship in Fas and Fas-ligand expression was observed in CD4+ T helper (Th)1- and Th2-type clones, and Fas mRNA was predominantly detected in Th2 clones, whereas Fas-ligand mRNA was principally found in Th1 clones. The two Th0 clones tested expressed both Fas and Fas-ligand, but only one exhibited cytolytic activity, whereas both were sensitive to CD4-mediated lysis. A functional consequence of the inverse Fas-Fas-ligand expression pattern was that Th2 and Th0 cells were sensitive to lysis by both Th1 CD4+ CTL and a CD8+ CTL clone in a Fas-dependent manner. These results suggest that cytolytic CD4+ Th1 cells may play an immunomodulatory role, regulating a Th2/Th0 response by Fas-mediated lysis. 相似文献
5.
Hiroji Shinkawa Shogo Tanaka Shigekazu Takemura Ryosuke Amano Kenjiro Kimura Masahiko Kinoshita Kanae Takahashi Shuichiro Matsuzaki Shoji Kubo 《Surgery》2021,169(4):922-928
BackgroundExtrahepatic recurrence and early intrahepatic recurrence of hepatocellular carcinoma after hepatic resection are indicative of poor prognoses. We aimed to develop nomograms to predict extrahepatic recurrence and early intrahepatic recurrence after hepatic resection.MethodsThe participants of this study were 1,206 patients who underwent initial and curative hepatic resection for hepatocellular carcinoma. Multivariate logistic regression analyses using the Akaike information criterion were used to construct nomograms to predict extrahepatic recurrence and early intrahepatic recurrence (within 1 year of surgery) at the first recurrence sites after hepatic resection. Performance of each nomogram was evaluated by calibration plots with bootstrapping.ResultsExtrahepatic recurrence was identified in 95 patients (7.9%) and early intrahepatic recurrence in 296 patients (24.5%). Three predictive factors, α-fetoprotein >200 ng/mL, tumor size (3–5 cm or >5 cm vs ≤3 cm), and image-diagnosed venous invasion by computed tomography, were adopted in the final model of the extrahepatic recurrence nomogram with a concordance index of 0.75. Tumor size and 2 additional predictors (ie, multiple tumors and image-diagnosed portal invasion) were adopted in the final model of the early intrahepatic recurrence nomogram with a concordance index of 0.67. The calibration plots showed good agreement between the nomogram predictions of extrahepatic recurrence and early intrahepatic recurrence and the actual observations of extrahepatic recurrence and early intrahepatic recurrence, respectively.ConclusionWe have developed reliable nomograms to predict extrahepatic recurrence and early intrahepatic recurrence of hepatocellular carcinoma after hepatic resection. These are useful for the diagnostic prediction of extrahepatic recurrence and early intrahepatic recurrence and could guide the surgeon’s selection of treatment strategies for hepatocellular carcinoma patients. 相似文献
6.
Shigekazu Uga Hideo Nishigori Satoshi Ishikawa 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》1994,232(7):415-420
Nishigori et al. reported a transient cataract model after administering glucocorticoid to a 15-day-old chick. Biochemically, the mechanism of onset of this cataract was thought to be related to damage caused by the formation of oxidative stresses and by a protein-water phase separation. There appear to be no reports on changes in the fine structure. After hydroocortisone succinate sodium was administered to 15-day-old chick embryos, the lenses were removed at 12, 24, 30, 48, 72 and 96 h and put in 4% gluraldehyde. The specimens were examined by light, transmission and scanning electron microscopy. Twelve to 24 h after administration to chick embryos, lens fibers containing electron-dense cytoplasm began to appear in the bow area of the equator and were still present thereafter. Thirty to 48 h after administration, numerous vacuoles of varying sizes began to appear in the lens in sites corresponding to the opaque region. These vacuoles, ranging from 2 to 8 m in diameter, were distributed in the intercellular spaces between the lens fibers. The vacuoles had disappeared by 96 h after administration, but during that period, the height of the epithelial cells in the equatorial region and the elongation of the equatorial lens fibers had become irregular. Transient opacity was due to the presence of vacuoles of various sizes, occurring in the intercellular space between the lens fibers around the lens nucleus. Moreover, the effect of glucocorticoid administration was noted in the lens epithelium and the lens fibers in the equatorial region. 相似文献
7.
Perioperative Oral Administration of Cystine and Theanine Enhances Recovery After Distal Gastrectomy
Tomohiro Miyachi MD Takashi Tsuchiya MD PhD Atsushi Oyama MD PhD Takahiro Tsuchiya MD Naomi Abe RD Atsuko Sato RD Yasumasa Chiba MSc Shigekazu Kurihara PhD Tetsuro Shibakusa PhD Takashi Mikami BVSc 《JPEN. Journal of parenteral and enteral nutrition》2013,37(3):384-391
Background: It has been reported that cystine and theanine, amino acids related to glutathione synthesis, have immunomodulatory effects, such as suppressing inflammation after strenuous exercise. In this study, we examined the effects of oral administration of cystine and theanine during the perioperative period as a pilot study. Methods: Forty‐three cases of distal gastrectomy for cancer conducted in our department were assigned to the cystine and theanine group (CT group) or to the placebo control group (P group), and a randomized, single‐blind, parallel‐group study was then performed. Cystine (700 mg) and theanine (280 mg) or a placebo was administered to participants for 10 continuous days (4 days before to 5 days after surgery). Changes in pre‐ and postoperative interleukin (IL)–6, C‐reactive protein (CRP), albumin, white blood cell (WBC) count, neutrophil count, total lymphocyte count, resting energy expenditure (REE), and body temperature were compared and examined. Results: Ten patients were excluded, leaving 33 patients in the study. The CT group had significantly lower IL‐6 values (postoperative day [POD] 4), CRP levels (POD 7), neutrophil counts (POD 4), and body temperatures (POD 5) than the P group (P < .05). In addition, REE in the P group peaked on day 1 (1.14 ± 0.16 [pre‐ and postoperative ratio]), whereas the CT group did not show any increase on POD 1 (0.99 ± 0.21, P < .05 vs P group). Conclusions: This study suggests that oral administration of cystine and theanine during the perioperative period may alleviate postgastrectomy inflammation and promote recovery after surgery. 相似文献
8.
Serum markers of liver fibrosis and histologic severity of fibrosis in resected liver 总被引:5,自引:0,他引:5
Tsukamoto T Yamamoto T Ikebe T Takemura S Shuto T Kubo S Hirohashi K Kinoshita H 《Hepato-gastroenterology》2004,51(57):777-780
BACKGROUND/AIMS: Serum concentrations of the 7S fragment of type IV collagen (7S collagen), amino-terminal propeptide of type III procollagen (PIIIP), and hyaluronic acid (HA) have been reported to serve as serologic markers of liver fibrosis in hepatitis and cirrhosis. We investigated whether these fibrosis markers reliably reflect histologic changes in the livers of patients with hepatocellular carcinoma. METHODOLOGY: Subjects included 165 patients undergoing liver resection for hepatocellular carcinoma. Most were seropositive for chronic hepatitis B or C. Histopathologic changes in liver tissue resected with the tumor were scored according to Knodell's histologic activity index. Serum was sampled for assays shortly before surgery. RESULTS: Significant correlations were found between hepatitis activity score and 7S collagen, PIIIP, and HA. Concentrations of 7S collagen differed significantly between activity grades, but differences were not significant for PIIIP or HA. Significant correlations were found between fibrosis staging score and all these three markers. When patients were divided according to activity grade, 7S collagen showed stronger correlation with fibrosis staging score than did PIIIP or HA. CONCLUSIONS: The 7S collagen fragment correlated more strongly than PIIIP or HA with stage and activity grade in patients with hepatocellular carcinoma. However, overlapping of results between histologically defined groups appeared to limit clinical diagnostic usefulness of all markers in individual patients. 相似文献
9.
Nanashima A Kinoshita N Nakanuma Y Zen Y Sumida Y Abo T Hidaka S Takeshita H Yasutake T Hayashi T Nagayasu T 《Hepato-gastroenterology》2008,55(85):1167-1173
BACKGROUND/AIMS: Intraductal papillary neoplasm of the bile duct (IPNB) represents a biliary papillary tumor mainly growing in the bile duct lumen resembling intraductal papillary mucin-producing neoplasm of the pancreas. However, its clinical spectrum and characteristics have not been fully evaluated. METHODOLOGY: To define the clinicopathologic characteristics and prognosis of IPNB patients, 6 cases of IPNB who underwent surgical resection are presented. RESULTS: Patients were 3 males and 3 females, aged between 47 and 79 years. Five patients had histories of hepatobiliary disease. Imagery showed cystic or diffuse dilatation of the bile ducts. Tumor markers were not valuable for diagnosis. All patients underwent hemihepatectomy with or without resection of the caudate lobe or extrahepatic bile duct. Examination showed polypoid tumors in 5 cases though 1 case had no evident tumor. Mucin was observed in 3 cases. Five cases were well-differentiated adenocarcinoma and 1 had poorly differentiated adenocarcinoma. Vascular invasion was rare and lymph node metastasis was not observed. In-situ spread of carcinoma was seen along biliary mucosa in 3 cases. Five cases survived without tumor relapse for long periods but 1 died of tumor recurrence at 31 months. CONCLUSIONS: Complete resection of IPNB based on accurate preoperative assessment of tumor extension provides a good prognosis. 相似文献
10.