Search results for "Benzene"
showing 10 items of 1701 documents
Intraoperative localization of malignant pheochromocytoma by 123-i-metaiodobenzylguanidine single probe measurement
1988
Metaiodobenzylguanidine (MIBG) imaging is a well-established method for locating intra- and extraadrenal pheochromocytomas. We investigated whether preoperative injection of 123-I-MIBG might be useful for intraoperative staging of chromaffine tumor cells. This was performed in a 46-year-old patient in whom the diagnosis of a malignant pheochromocytoma had been established by 123-I-MIBG imaging and enhanced catecholamine secretion. The rationale for intraoperative staging in this patient was a discrepancy between computed tomography (CI) of the abdomen and the radionuclide imaging, because scintigraphy revealed a mass with MIBG uptake in the right lower abdomen that could not be visualized b…
Brain met-enkephalin immunostaining after subacute and subchronic exposure to benzene
1994
Benzene is used in a wide variety of domestic and occupational activities, and due to its lipophilic nature, it accumulates in lipid-rich tissues like the brain. In this sense, neurotoxic action has long been associated with organic solvent exposure and it has been shown that benzene, injected in a single dose or during a prolongued administration, modifies the content of dopamine, noradrenaline, serotonin and its main metabolite 5-hydroxy indolacetic acid, in several brain regions of the rat, then revealing a stimulating action on brain monoamine synthesis and turnover. However, information concerning neurotoxic action of benzene exposure in vivo on peptidergic neuromodulatory systems is s…
Studies on the induction of gene mutations in bacterial and mammalian cells by the ring-opened benzene metabolites trans,trans-muconaldehyde and tran…
1990
t,t-Muconaldehyde and t,t-muconic acid have been investigated for the induction of gene mutations in Salmonella typhimurium (reversion of the his- strains TA97, TA98, TA100, TA102, TA104 and TA1535), Escherichia coli (reversion of the trp- strain WP2 uvrA) and Chinese hamster V79 cells (acquisition of resistance toward 6-thioguanine). t,t-Muconaldehyde proved weakly mutagenic in strain TA104 in the presence and absence of NADPH-fortified postmitochondrial fraction from rat liver homogenate (S9 mix). In strains TA97, TA100 and TA102, weak positive responses were observed only in the presence of S9 mix. In strains TA98, TA1535 and WP2 uvrA, the result was negative. In V79 cells, the mutation …
A novel rat model of chronic fibrosing cholangitis induced by local administration of a hapten reagent into the dilated bile duct is associated with …
2000
Abstract Background/Aim: The cholangiopathies represent hepatobiliary diseases in which bile-duct epithelial cells are targets for destructive processes, including immune-mediated damage. We describe a novel rat model of chronic fibrosing cholangitis induced by administration of the hapten reagent 2,4,6-trinitrobenzenesulfonic acid (TNBS) into the dilated bile duct. Methods: The common bile duct was dilated due to a mild stenosis in 8-week-old female Lewis rats. TNBS (50 mg/kg) was injected during a second laparotomy. Results: TNBS-treatment reproducibly resulted in chronic fibrosing cholangitis. In retrograde cholangiography the bile ducts showed irregularities, beading and strictures. Alk…
Intussusceptive Remodeling of Vascular Branch Angles in Chemically-Induced Murine Colitis
2013
Intussusceptive angiogenesis is a developmental process linked to both blood vessel replication and remodeling in development. To investigate the prediction that the process of intussusceptive angiogenesis is associated with vessel angle remodeling in adult mice, we systematically evaluated corrosion casts of the mucosal plexus in mice with trinitrobenzesulphonic acid (TNBS)-induced and dextran sodium sulfate (DSS)-induced colitis. The mice demonstrated a significant decrease in vessel angles in both TNBS-induced and DSS-induced colitis within 4 weeks of the onset of colitis (p<.001). Corrosion casts 28–30 days after DSS treatment were studied for a variety of detailed morphometric changes.…
Downregulation of nNOS and synthesis of PGs associated with endotoxin-induced delay in gastric emptying
2002
A single intraperitoneal injection of endotoxin (40 μg/kg) significantly delayed gastric emptying of a solid nutrient meal. Blockade of nitric oxide synthase (NOS) with 30 mg/kg ip N G-nitro-l-arginine methyl ester or 20 mg/kg ip 7-nitroindazole [neuronal NOS (nNOS) inhibitor] significantly delayed gastric emptying in control animals but failed to modify gastric emptying in endotoxin-treated rats. Administration of 2.5, 5, and 10 mg/kg ip N 6-iminoethyl-l-lysine [inducible NOS (iNOS) inhibitor] had no effect in either experimental group. Indomethacin (5 mg/kg sc), NS-398 (cyclooxygenase-2 inhibitor; 10 mg/kg ip), and dexamethasone (10 mg/kg sc) but not quinacrine (20 mg/kg ip) significantl…
Involvement of the P2X7 purinergic receptor in colonic motor dysfunction associated with bowel inflammation in rats
2014
Background and Purpose Recent evidence indicates an involvement of P2X7 purinergic receptor (P2X7R) in the fine tuning of immune functions, as well as in driving enteric neuron apoptosis under intestinal inflammation. However, the participation of this receptor in the regulation of enteric neuromuscular functions remains undetermined. This study was aimed at investigating the role of P2X7Rs in the control of colonic motility in experimental colitis. Experimental Approach Colitis was induced in rats by 2,4-dinitrobenzenesulfonic acid. P2X7R distribution was examined by immunofluorescence analysis. The effects of A804598 (selective P2X7R antagonist) and BzATP (P2X7R agonist) were tested on co…
Validation of a modified model of TNBS-induced colitis in rats. How to induce a chemical colitis in rats
2014
Background: there are no standard practice in the induction of colitis by 2,4,6-trinitrobenzene sulfonic (TNBS) acid. Usually, the repeated administration of TNBS is preferred, because it will result in a local Th1 response that has the characteristics of Crohn's disease. material and Methods: A total of 30 rats were randomized into two groups, consisting of a saline control group of ten rats and a TNBS groups of 20 rats. After the animals were anesthesized, 0,5 ml of either 0,9 % saline 8controls) or TNBS 50 mg/Kg dissolved in 50% ethanol were instilled into the colon through a rubber catheter. The experiment was repeated weekly for four weeks, then, the rats were killed at day 40, and the…
Consistency of effect of ezetimibe/simvastatin compared with intensified lipid-lowering treatment strategies in obese and non-obese diabetic subjects
2013
Purpose: This post hoc analysis assessed switching to ezetimibe/simvastatin 10/20 mg vs doubling the baseline statin dose to simvastatin 40 mg or atorvastatin 20 mg or switching to rosuvastatin 10 mg in subgroups of obese (BMI ≥30 kg/m 2 ) and non-obese (BMI <30 kg/m 2 ) diabetic subjects. Methods: This was a randomized, double-blind, 12-week study of adults 18–79 years with cardiovascular disease with low-density lipoprotein cholesterol (LDL-C) ≥70 and ≤160 mg/dl. Percent change in LDL-C and other lipids was estimated. Results: In obese subjects (n = 466), percent changes in LDL-C and most other lipids were greater with ezetimibe/ simvastatin vs doubling the baseline statin dose or switchi…
A comparison of efficacy and safety of an ezetimibe/simvastatin combination compared with other intensified lipid-lowering treatment strategies in di…
2013
The low-density lipoprotein cholesterol (LDL-C) lowering efficacy of switching to ezetimibe/simvastatin (EZ/S) 10/20 mg versus doubling the run-in statin dose (to simvastatin 40 mg or atorvastatin 20 mg) or switching to rosuvastatin 10 mg in subjects with cardiovascular disease (CVD) and diabetes was assessed. Endpoints included percentage change in LDL-C and percentage of patients achieving LDL-C <70 mg/dL. Significantly greater reductions in LDL-C occurred when switching to EZ/S versus statin doubling in the overall population and in subjects treated with simvastatin 20 mg or atorvastatin 10 mg (all p < 0.001). The LDL-C reduction was numerically greater when switching to EZ/S vers…