Search results for "Hamster"
showing 10 items of 141 documents
Stable expression of human cytochrome P450 1A1 cDNA in V79 Chinese hamster cells and metabolic activation of benzo[a]pyrene
1993
A V79 Chinese hamster cell line stably expressing human cytochrome P450 1A1 (CYP1A1) was obtained by chromosomal integration of the human CYP1A1 cDNA under the control of the SV40 early promoter. Chromosomal integration was verified by Southern analysis, and effective transcription of the human CYP1A1 cDNA was demonstrated by Northern analysis. The CYP1A1 cDNA-encoded protein was characterized by Western analysis using anti-rat CYP1A1. Intracellular association of CYP1A1 with the endoplasmic reticulum could be visualized by in situ immunofluorescence. Crude cell lysates of the V79 derived cell line was able to catalyze 7-ethoxyresorufin-O-deethylation (EROD) with an activity of about 50 pmo…
Genetically engineered V79 chinese hamster cell expression of purified cytochromeP-450iib1 monooxygenase activity
1989
Chinese hamster V79 fibroblasts, frequently used as target cells in short-term tests for mutagenicity, do not possess measurable monooxygenase activity; in particular, enzymatic oxidation of testosterone (T) cannot be demonstrated. If these V79 cells, however, had been transfected with the cDNA-encoding rat liver cytochrome P-450IIB1 under control of the SV40 early promoter, they stably expressed monooxygenase activity. These so-called SD1 cells then oxidatively metabolized T at a rate of 27 pmol/mg protein/min, converting it to 16 alpha- and 16 beta-hydroxy-T as well as 4-androsten-3,17-dione as sole metabolites in a ratio of 1.1:1.0:1.6. The regio- and stereoselective conversion of T by S…
Echinostoma caproni: intestinal pathology in the golden hamster, a highly compatible host, and the Wistar rat, a less compatible host.
2005
The histopathological changes induced by Echinostoma caproni (Trematoda: Echinostomatidae) in a high (golden hamster) and a low compatible host (rat) were compared at 15 and 30 days post-infection. Infection of rats was characterized by a progressive increase in erosion of villi and elevated numbers of goblet cells, which could be related to the early expulsion of the parasite in a host of low compatibility. In contrast to rats, the number of goblet cell in E. caproni-infected hamsters was low, but increased numbers of neutrophils and mesenteric inflammatory cells were observed. This indicated that local inflammatory responses in hamsters were greater than in rats. An immunohistochemical st…
Photoperiod effects on bombesin- and cholecystokinin-like immunoreactivity in the suprachiasmatic nuclei of the Djungarian hamster (Phodopus sungorus)
1991
The immunocytochemical distribution of the putative satiety peptides bombesin (BBS) and cholecystokinin (CCK) were studied in the hypothalamic suprachiasmatic nuclei (SCN) of male and female Djungarian hamsters (Phodopus sungorus) held under either long (light/dark, LD 16:8 h) or short (LD 8:16) photoperiod. The animals were killed by perfusion with a fixative at the middle of the light period and the tissue was processed by routine immunohistochemical methods. Perikarya exhibiting BBS- or CCK-like immunoreactivity (LI) were found in the SCN of animals of all groups. Sex-related differences were not observed. In contrast, long-term exposure to short days decreased the number of neurons exhi…
Use of monoclonal and polyclonal antibodies as structural and topographical probes for hepatic epoxide hydrolase
1983
AbstractMonoclonal antibodies have been prepared against rat liver epoxide hydrolase (EH), some of which gave precipitation lines on immunodiffusion against pure EH suggesting the presence of repetitive structural domains on the enzyme. Using ELISA, with polyclonal antibodies to rat and rabbit liver EH, reactivity and therefore structural similarities between EH of all species tested, including human, were observed. This was in contrast to immunodiffusion results demonstrating the limitations of the latter technique. Using monoclonal antibodies in ELISA, greatest structural similarity was between rat, mouse, and Syrian hamster EH and relatively little between rat and human. Two of the antib…
Metabolic activation to a mutagen of 3-hydroxy-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene, a secondary metabolite of benzo[a]pyrene
1987
3-Hydroxy-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (3-OH-BP-7,8-diol) was isolated from arylsulfatase/beta-glucuronidase-treated bile of rats to which 3-hydroxybenzo[a]pyrene (3-OH-BP) has been administered. This triol was investigated for mutagenicity in Salmonella typhimurium (reversion to histidine prototrophy of strains TA 97, TA 98, TA 100 and TA 1537) and in V79 Chinese hamster cells (acquisition of resistance to 6-thioguanine). When no exogenous metabolizing system was added the triol was inactive, while 3-OH-BP showed weak mutagenic effects with all four bacterial strains. In the presence of NADPH-fortified postmitochondrial supernatant fraction (S9 mix) of liver homogenate fro…
Biphenyl and fluorinated derivatives: liver enzyme-mediated mutagenicity detected in Salmonella typhimurium and Chinese hamster V79 cells.
1992
Abstract Hepatocarcinogenic polychlorinated and polybrominated biphenyls usually show negative results in in vitro mutagenicity assays. Problems in their testing result from their low water solubility and their slow rate of metabolism. We therefore investigated better soluble model compounds, namely biphenyl and its 3 possible monofiuorinated derivatives. In the direct test, these compounds proved tobe nonmutagenic in Salmonella typhimurium TA98 and TA100 (reversion to histidine prototrophy) and in Chinese hamster V79 cells (acquisition of resistance to 6-thioguanine). However, when the exposure was carried out in the presence of NADPH-fortified postmitochondrial fraction of liver homogenat…
Development and validation of a radioimmunoassay for serum melatonin.
1989
A radioimmunoassay using N-[3-(4-hydroxy-3-[4-hydroxy-3- [125I]iodophenylpropionyl)]-5-methoxytryptamine as tracer for determination of melatonin in the serum of different species is described. Melatonin antisera were raised in rabbits by immunization with a bovine serum albumin conjugate of N-[3-(2-aminoethyl)-5-methoxy indole] hemisuccinamide. A single high affinity, specific antiserum was obtained. In contrast to previous studies, the tracer was synthesised in one step in the absence of water, giving an excellent yield of highly pure product. No chromatographic purification step was needed. Polyethylene glycol in combination with goat antirabbit immunoglobulins was used to separate bound…
The new radioligand [H-3]-L 748,337 differentially labels human and rat beta(3)-adrenoceptors
2013
As no suitable radioligand exists for the detection of β3-adrenoceptors, we have explored the radioligand binding properties of a tritiated version of the selective β3-adrenoceptor antagonist L 748,337. Kinetic and equilibrium saturation and competition binding experiments were performed with [(3)H]-L 748,337 on membrane fractions of HEK and CHO cells stably transfected with human and rat β-adrenoceptor subtypes. Based on both association/dissociation kinetic and equilibrium saturation binding studies in transfected HEK cells, [(3)H]-L 748,337 exhibited an affinity of approximately 2 nM for human β3-adrenoceptors. Competition studies with agonists and subtype-selective antagonists validated…
Activation of propane 2-nitronate to a genotoxicant in V79-derived cell lines engineered for the expression of rat hepatic sulfotransferases
1999
2-Nitropropane (2-NP) is a genotoxic hepatocarcinogen in rats. The genotoxicity of the compound has been attributed to a sulfotransferase-mediated formation of DNA-reactive species from the anionic form of 2-NP, propane 2-nitronate (P2N). Several observations have suggested that sulfotransferases (SULTs) 1A1 and/or 1C1 may be important in the activation of P2N to a genotoxicant in rat liver, but a definite proof is lacking. In order to identify the sulfotransferase(s) of rat liver that are capable of activating P2N, we have investigated the genotoxicity of P2N in various V79-derived cell lines engineered for expression of individual forms of rat hepatic sulfotransferases. Genotoxicity was a…