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951.
A conflict procedure in pigeons was used to characterize the antipunishment effects of the putative mixed 5-hydroxytryptamine (5-HT)1A agonist/5-HT2A/2C antagonists WY 50,324, CGS 18102A, LEK 8804 and FG 5974 and to further investigate interactions between the antipunishment effects of the 5-HT1A agonists buspirone and 8-OH-DPAT [8-hydroxy-2-(di-n-propylamino)tetralin] administered in combination with the mixed 5-HT2A/2C antagonist ritanserin and the alpha 1 antagonist prazosin. The 5-HT1A agonists, buspirone and 8-OH-DPAT, which lack affinity for 5-HT2A/2C receptors, produced dose-related increases in punished responding. Of the compounds with a mixed binding profile, only WY 50,324 showed effects that were comparable to those observed after 8-OH-DPAT, whereas FG 5974 and CGS 18102A exhibited limited effects on punished responding, and LEK 8804 was ineffective. Administration of a relatively low, behaviorally active dose of ritanserin (0.16 mg/kg) significantly enhanced the potency of 8-OH-DPAT and buspirone to increase punished responding from 8 to 50-fold without altering their effects on unpunished responding. Importantly, ritanserin failed to increase the number of doses of 8-OH-DPAT that significantly increased punished responding. In contrast, prazosin (2.5 mg/kg) significantly enhanced the potency and increased the number of doses of buspirone exerting significant effects on punished responding, but did not alter the effects of 8-OH-DPAT. Taken together, the results neither explain the suggested greater efficacy in producing anxiolytic effects of compounds with putative mixed 5-HT1A agonist and 5-HT2A/2C antagonist properties, nor confirm a proposed interaction between alpha1 adrenoreceptors and 5-HT1A agonists in preclinical tests of anxiolytic activity. 相似文献
952.
953.
M Ansaruzzaman M Rahman AK Kibriya NA Bhuiyan MS Islam MJ Albert 《Canadian Metallurgical Quarterly》1995,33(5):1339-1340
The sucrose-containing selective medium thiosulfate-citrate-bile salt-sucrose agar missed a sucrose nonfermenting and four sucrose late-fermenting variant strains of Vibrio cholerae O139 Bengal from diarrheal stools. These strains were, however, correctly identified as V. cholerae O139 on a sucrose-deficient selective medium, taurocholate-tellurite-gelatin agar. 相似文献
954.
B Ault MS Miller MD Kelly LM Hildebrand WG Earley D Luttinger JP Mallamo SJ Ward 《Canadian Metallurgical Quarterly》1995,34(12):1597-1606
NMDA channel blockers are potentially advantageous therapeutic agents for the treatment of ischemia and head trauma, which greatly elevate extracellular glutamate, because they should most effectively inhibit high levels of receptor activation. A novel high affinity TCP site ligand, WIN 63480, does not produce MK-801- or PCP-like behavioral activation at anti-ischemic doses. While WIN 63480, MK-801 and PCP were all observed to be effective blockers of open NMDA channels, WIN 63480 had much less access to closed NMDA channels. This difference may be due to the fact that WIN 63480 is hydrophilic (logD = -4.1) while MK-801 and PCP are lipophilic (logD = +1.8). In vivo, closed channel access may result in a non-competitive profile of antagonism for MK-801 and PCP compared to a more uncompetitive profile for WIN 63480. Release of glutamate, and depolarization, are likely to produce a high level of NMDA receptor activation in ischemic areas compared to normal tissue. Consequently, at anti-ischemic doses, WIN 63480 may produce less inhibition of physiological NMDA-mediated processes in neural systems involved in behavioral regulation than MK-801 or PCP, leading to an improved side effect profile. 相似文献
955.
Evidence for the relationship of calcium to blood pressure 总被引:1,自引:0,他引:1
956.
H Vais MS Williamson CA Hick N Eldursi AL Devonshire PN Usherwood 《Canadian Metallurgical Quarterly》1997,413(2):327-332
As a model for establishing an optimized medium for human in vitro fertilization (IVF), modified human tubal fluid (HTF) media containing amino acids at concentrations found in human serum and follicular fluid were prepared, and the effect of the media on development of random-bred (ICR) and F1 hybrid (CBF1) mice embryos was studied. The total concentrations of amino acids found in serum and follicular fluid were about one-third to one-half the concentrations present in two conventional media used in human IVF: Ham's F-10 and Eagle's minimal essential medium (MEM). When ICR mouse embryos were cultured in the HTF medium containing 21 amino acids at concentrations found in follicular fluid, the number of embryos developing to morulae at 72 h and to blastocysts at 96 h increased in comparison with those cultured in HTF medium. When HTF containing amino acids at concentrations found in serum was used, only induced morula formation at 72 h was enhanced. The number of hatching blastocysts at 96 h also increased when CBF1 mouse embryos were cultured with HTF supplemented with amino acids at concentrations found in follicular fluid. When ICR mouse embryos were cultured in modified HTF media containing concentrations of amino acids found in Ham's F-10 and MEM that contained higher concentrations of glutamine, embryo development was inhibited. The amount of ammonium produced during incubation for 3 days was significantly less when embryos were cultured in media containing concentrations of amino acids found in follicular fluid compared with when Ham's F-10 or MEM was the culture medium. Ammonium is produced by the breakdown of glutamine in the culture medium during incubation with or without embryos. These results suggest that the concentrations of amino acids found in follicular fluid are more effective and safer for embryo culture than those in other media currently in use. 相似文献
957.
Struma has called for treatment very early in medical history due to its appearance. At the beginning of our calendar, the physicians dealt with this problem already. This paper gives a historical review about the surgical treatment of struma. 相似文献
958.
The objective of the study was to evaluate the chronic cytotoxic effect of very low nontoxic aluminum (Al) in the drinking water of rats. The control group (10 rats) received deionized water, whereas the two experimental groups (10 rats each) received Al in a dose of 5 mg and 20 mg/kg bw/day, respectively. Al was applied in their drinking water during the 6-month duration of the study. Light and electron microscopy (EM) was performed on several body tissues (i.e., kidney, liver muscle, brain). The results showed distinct dose-dependent changes in kidney and brain. In tubulo-interstitial part of the kidney many proximal tubules were hyperdilated. Their cells were swollen and the microvilli were largely lost. Atrophy of some tubules, surrounded by focal areas of interstitial fibrosis was also observed. Some of the glomeruli were undergoing partial sclerosis and in many focal mesangial hypercellularity was found. No distinct morphological changes in other peripheral tissues were observed. In brain, most pronounced changes were observed in hippocampus: they include spongioform changes in pyramidal layer, nuclear deformity and presence of vaculoes in the nuclei. Neurofibrillary degeneration, similar to neurofibrillary tangles in Alzheimer's disease, was also observed. It can thus be concluded that despite very low gastrointestinal absorption (less than 1%), Al in drinking water might accumulate in the long term in vital organs such as kidney and brain, with distinct cytotoxic and neurotoxic effects. 相似文献
959.
960.