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1.
The mechanisms of histamine-induced contraction and relaxation were investigated in rings isolated from a middle part of the left descending coronary arteries of horses. Intact and endothelium-denuded preparations were compared. Rings of horse coronary arteries contracted in response to histamine in a concentration dependent manner, but some of them relaxed with lower concentrations and contracted with higher concentrations. Removal of the endothelium abolished the relaxation and potentiated the contraction. The pD2 values were 4.70 +/- 0.08 in the rings with intact endothelium and 4.95 +/- 0.08 in endothelium-denuded rings. Histamine-induced contractions in intact and denuded preparations were not affected by an H2-antagonist, cimetidine, but were inhibited by an H1-antagonist, diphenhydramine in non-competitive manner in the rings with endothelium and in competitive manner in denuded rings. After precontraction with PGF2 alpha or norepinephrine, histamine relaxed preparations with intact endothelium (pD2 value, 7.80 +/- 0.11), although histamine-induced relaxations were not observed in denuded preparations. The relaxation was competitively inhibited by diphenhydramine. Relaxing response was significantly attenuated by methylene blue, quinacrine, L-nitro-arginine, gossypol and AA861 but not by indomethacin. These results suggest that the histamine-induced contraction and relaxation in horse coronary arteries are mediated mainly by H1-receptors in the smooth muscle and endothelium, respectively, and H1-receptor activation of endothelial cells may liberate vasodilator substances.  相似文献   
2.
Colonic mucosal mast cells are implicated in the pathogenesis of visceral hypersensitivity associated with irritable bowel syndromes. This study was designed to investigate the roles of mucosal mast cells in development of an experimental visceral hypersensitivity induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in rats. TNBS, when injected into the proximal colon through laparotomy, produced a significant decrease in pain threshold of the distal colon to mechanical distention, indicating a visceral hypersensitivity. In the proximal colon that was directly insulted by TNBS, mucosal necrosis and extensive inflammatory cell infiltration were observed with concomitant increase in tissue myeloperoxide (MPO) activity. In the distal colon where distention stimuli were applied, the number of mucosal mast cells significantly increased following TNBS treatment, although neither mucosal injury nor increase in tissue MPO activity was observed. In an organ culture, spontaneous release of a mucosal mast cell-specific protease (RMCP-2) from the distal colon tissue of TNBS-treated rats was significantly larger than that of sham animals. Furthermore, TNBS-induced visceral hypersensitivity was significantly suppressed by subcutaneous pretreatment with a mast cell stabilizer doxantrazole in a dose-dependent manner. These findings suggest that prominent colonic mast cell infiltration associated with an enhanced spontaneous mediator release is responsible, at least partly, for development of visceral hypersensitivity induced by TNBS in rats.  相似文献   
3.
A series of novel 4,5-dihydropyrazole-5-thiones (DHPs) was synthesised by treating the corresponding dihydropyrazolones with ‘Lawesson’s reagent and evaluated for miticidal activity against two-spotted spider mites (Tetranychus urticae Koch). Of these, 3-(4-chlorophenyl)-4,4-dimethyl-1-phenyl-4,5-dihydropyrazole-5-thione, 3-(4-chlorophenyl)-4-ethyl-4-methyl-1-phenyl-4,5-dihydropyrazole-5-thione, 3-(4-chlorophenyl)-1-phenyl-4,5-dihydropyrazole-5-thione-4-spirocyclopentane and 4,4-dimethyl-1-phenyl-3-(4-trifluoromethyl-phenyl)-4,5-dihydropyrazole-5-thione were highly active (pEC50>4·0) and were more effective than the miticide dicofol (pEC50=3·879), which has traditionally been used for the control of phytophagous mites. Structure–activity relationship (SAR) studies were performed on each position of the pyrazole ring of DHPs. The results indicated that the unsubstituted phenyl, 4-substituted phenyl and thioxo groups on the 1-, 3- and 5-positions of DHPs respectively were required for activity. Quantitative SAR studies using physicochemical parameters of substituents and the capacity factor k′ as a hydrophobicity index suggested that: (a) the activities of all types of DHPs examined were mainly dominated by hydrophobicity, (b) the bulkiness of 4-substituents of the 3-phenyl ring favoured the activity and (c) the log k′ optimum for all DHPs was 1·675, equivalent to a log Pow value of c. 5·0.  相似文献   
4.
5.
In this study, we showed that feeding rats the organic extract of scallop shells (scallop shell extract) caused a decrease in the weights of white adipose tissues in rats fed a high-fat diet. In addition, the cholesterol concentration in the serum of rats that received a diet containing scallop shell extract was significantly lower than that in the serum of rats on the control diet. Feeding this scallop shell extract to rats increased the fecal weight as well as the fecal excretion of bile acids. The amino acid composition of the feces from rats fed the scallop shell extract was different from that of feces from rats fed the control diet, and treatment of the extract with pepsin and pancreatin identified a protein with a molecular weight of 90 kDa (90-kDa protein) as one of the indigestible proteins. Interestingly the 90-kDa protein was found to be identical to a free radical-scavenging protein we previously identified and showed the ability to bind bile acids. These results suggest that indigestible proteins (resistant proteins) in the scallop shell extract, including the 90-kDa protein, inhibit the absorption of bile acid by binding to it and cause increased excretion of fecal bile acid, which subsequently may decrease the serum cholesterol level.  相似文献   
6.
ABSTRACT:   In molluscs, mantle epithelial cells secrete organic matrix proteins to form shells. In this study, we established a culture of mantle epithelial cells by using the mantle pallial layer of scallops. We aimed to identify the mantle epithelial cells expressing scallop shell matrix proteins and establish a culture system of epithelial cells. After the mantle pallial layer was carefully isolated from the mantle tissue, explant culture was performed at 4°C. Most cells that migrated from the explant tissue were round cells. Most of the adhered cells retained round morphology, while some of the cells adhered to the dish and showed morphology similar to that of epithelial-like and fibroblast-like cells. When the cultured cells were immunostained with a polyclonal antibody against the shell matrix protein, the antibody recognized many of the adhered cells. An estimation of the number of epithelial cells revealed that approximately 70% of the adhered cells were epithelial cells. This is the first report to describe epithelial cells in cultured mantle cells, which express shell matrix proteins. This culture system may be a useful method for characterization of the mantle epithelial cells.  相似文献   
7.
We have previously reported that the scallop shell extract possesses free radical scavenging activity. In this study, we isolated a glycoprotein with a molecular weight of approximately 90 kDa (named 90-kDa protein) which showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide anion radical scavenging, reducing, and ferrous ion-chelating activities. Amino acid composition analysis showed that the 90-kDa protein was rich in Asx (Asp or Asn), Ser and Gly residues. A BLAST search of partial amino acid sequences determined by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry revealed that the 90-kDa protein is a novel protein. The 90-kDa protein is a yellow protein that contains fluorescent substances. To the best of our knowledge, this is the first report of a radical scavenging protein from the scallop shell.  相似文献   
8.
Papaya seed represents a rich source of biologically active isothiocyanate   总被引:1,自引:0,他引:1  
In the present study, papaya (Carica papaya) seed and edible pulp were carefully separated and then the contents of benzyl isothiocyanate and the corresponding glucosinolate (benzyl glucosinolate, glucotropaeolin) quantified in each part. The papaya seed with myrosinase inactivation contained >1 mmol of benzyl glucosinolate in 100 g of fresh seed. This content is equivalent to that of Karami daikon (the hottest Japanese white radish) or that of cress. The papaya seed extract also showed a very high activity of myrosinase and, without myrosinase inactivation, produced 460 micromol of benzyl isothiocyanate in 100 g of seed. In contrast, papaya pulp contained an undetectable amount of benzyl glucosinolate and showed no significant myrosinase activity. The n-hexane extract of the papaya seed homogenate was highly effective in inhibiting superoxide generation and apoptosis induction in HL-60 cells, the activities of which are comparable to those of authentic benzyl isothiocyanate.  相似文献   
9.
Bacterial tests were used to assess bacterial contamination of game meat from Japanese wild boars. The bacterial contamination of wild boar meat was less than that of domestic pork, as determined by aerobic plate counts (APC) and coliform counts. None of the meat examined in this study was contaminated by Salmonella or E. coli O-157. To detect adulteration by domestic pig meat or European wild boar meat, 46 samples of game meat sold as Japanese wild boar were examined genetically. A total of 17 samples showed genetic haplotypes of European and Asian domestic pigs in the D-loop of mitochondrial DNA (mtDNA), and 16 samples showed nuclear glucosephosphate isomerase-processed pseudogene (GPIP) genotypes of European domestic pigs. The European GPIP genotypes of these samples were confirmed by PCR-RFLP analysis. These results indicate that some game meat sold as Japanese wild boar is adulterated by cross-breeding between pigs and wild boars or by contamination with meat from domestic pigs or European wild boars.  相似文献   
10.
When crude enzymes prepared from some vegetables and fruits were incubated with bisphenol A (2,2-bis(4-hydroxyphenyl)propane, BPA) at 37 degrees C, BPA was oxidized by crude enzymes from potato, eggplant, and lettuce. The crude enzyme prepared from potato (Solanum tuberosum) had the strongest oxidative activity for BPA. Its optimal temperature and pH were 40-45 degrees C and 8.0, respectively. More than 95% of BPA was oxidized after the incubation with potato enzyme for 60 min. BPA gave two oxidation products besides insoluble compounds during the oxidation by potato enzyme. The oxidation products were identified to be 4[1-(4-hydroxyphenyl)-1-methyl-ethyl]-benzene-1,2-diol and 4[1-(4-hydroxyphenyl)-1-methyl-ethyl]-benzene-1,3-diol. Enzymatically oxidized BPA lost the estrogen-like activity to enhance the growth of human breast cancer (MCF-7) cells.  相似文献   
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