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《Drug and chemical toxicology》2013,36(3):267-279
ABSTRACTThe long term effects of percutaneous, subcutaneous and intraperitoneal administration of sodium–ATP (NaATP) and ferric iron–ATP (FeATP) were studied on an animal model. Both compounds induce a generalized lymphoadenitis which in the case of FeATP led to lymphomas. The analytical study of the involved target tissues showed intracellular composition changes that result from the impairment of the cell membrane permeability. The morbidity and mortality rate were higher with FeATP which seems to be the result of two different, in intensity and duration, interactions with the cell plasma membrane. The influence of the changes in cellular calcium homeostasis, and its relationship with carcinogenesis and immuno response are discussed. 相似文献
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苦参碱及氧化苦参碱的药代动力学与药效动力学 总被引:39,自引:0,他引:39
以QTc延长率为效应指标,用药代动力学-药效动力学结合模型对苦参碱、氧化苦参碱iv后在免体内的处置和效应动力学作定量分析,两药的血浓时程均符合二房室模型,两药的效应与效应室浓度之间的关系均符合S形Emax模型。两药彼此的药动学和药效学性质均有明显差异,但它们各自的劳动学和药效学性质在所用剂量范围内均为非剂量依赖性。 相似文献
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1. The in vitro effects of histamine, some other Hi- and H2-receptor agonists and some antagonists were studied on the specific activities and kinetics of rat liver alcohol dehydrogenase (ADH), and cytoplasmic and mitochondrial liver aldehyde dehydrogenase (ALDH). 2. Histamine (H1- and H2-agonist) non-competitively inhibited ADH and ALDH, 2-(2-aminoethyl) pyridine (Hi-receptor agonist) non-competitively inhibited ADH. There were no changes of cytoplasmic and mitochondrial liver ALDH activities in the presence of 2-(2-aminoethyl) pyridine. 3. Betazole (H2-receptor agonist) produced a competitive inhibition of mitochondrial ALDH but not of ADH or cytoplasmic ALDH. 4. Diphenhydramine (H1-receptor antagonist) non-competitively inhibited ADH at a lower concentration. It stimulated mitochondrial ALDH activity without changes in cytoplasmic ALDH from control values. 5. Burimamide (H2-receptor antagonist) produced a biphasic and dose-dependent stimulation and non-competitive inhibition of ADH and it non-competitively inhibited ALDH in both cytoplasmic and mitochondrial fractions. Metiamide (H2-receptor antagonist) non-competitively inhibited all ADH and ALDH of both liver fraction studied. 6. It is concluded that liver ADH and ALDH activity can be altered by compounds which affect both Hi- and H2-histamine receptors and that these compounds may cause an in vivo potentiation and/or reduction of the toxic effect of ethanol. 相似文献
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目的:了解冰毒吸食者焦虑抑郁情绪和自我概念状况,探讨二者之间的关系,为临床心理干预提供依据。方法:采用抑郁自评量表(SDS),焦虑自评量表(SAS)和田纳西自我概念量表(TSCS)对36例强制戒毒的冰毒吸食者(研究组)和36例健康人群(对照组)进行调查,将结果进行统计学处理分析。结果:(1)研究组SDS,SAS评分明显高于对照组,差别具有统计学意义(P<0.01);(2)TSCS评分比较,研究组除自我批评因子分高于对照组外,其余各因子分均低于对照组,差异具有统计学意义(P<0.01);(3)TSCS与SAS和SDS之间具有高度相关性(r=0.411-0.462,P<0.01)。结论:冰毒吸食者焦虑抑郁情绪明显,表现为消极的自我概念;焦虑抑郁情绪影响自我概念。临床治疗中应关注戒毒者负性情绪和自我概念,采取有效措施帮助他们消除负性情绪,树立积极的自我概念,促进心理康复。 相似文献
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Günter Oberdörster 《Inhalation toxicology》2013,25(1):29-56
Chronic inhalation of fibrous and nonfibrous particles by rats at high concentrations results in lung tumor formation if the particles are poorly soluble in the lung. Even rather benign nonfibrous particles such as TiO 2 produce this result. One significant change during a chronic inhalation exposure of poorly soluble particles of low cytotoxicity (PSP) is an impairment of normal clearance mechanisms in the alveolar region of the lung in rats, resulting in a continued buildup to high lung burdens accompanied by chronic alveolar inflammation, fibrosis, and mutational events. Since these are obviously high-dose effects, questions about their extrapolation to humans exposed to much lower concentrations have been raised. Results of key studies reported for chronic inhalation of PSP in rats indicate that mechanisms of PSP-induced lung tumors at high doses do not operate at low dose levels. Furthermore, the existence of two thresholds can be postulated: One is a dosimetric threshold for the endpoint alveolar macrophage-mediated clearance, which is related to lung particle overload. The other is a mechanistic threshold for the endpoint mutation, which is determined by the level of antioxidant defenses to counter-balance reactive oxidant species released by activated inflammatory cells. A no-observed-adverse-effect level (NOAEL) could therefore be based on avoiding alteration of the toxicokinetic of the particles such that the lung burdens stay below the dosimetric threshold. The suggestion that PSP-associated organic compounds (e.g., diesel particulate matter) contribute to the lung tumor responses in rats observed in chronic inhalation studies is not supported by experimental data from in vivo studies. It can be concluded that high-dose rat lung tumors due to PSP should not be used for low-dose extrapolations, and no significant contribution to human lung cancer risk can be predicted from levels of PSP below lung overload. With respect to the pulmonary toxicokinetics of inhaled fibrous particles, the biopersistence of long fibers (>20 µm) which cannot be phagocytized by alveolar macrophages is a key parameter related to long-term carcinogenic effects. Long fibers with a very low biopersistence should not be considered as carcinogenic. Since the clearance kinetics of fibers can generally be described by a biphasic or multiphasic pattern - fast initial and slow final phase - it is essential that the slow phase of the retention kinetics of fibers longer than 20 µm is considered in a biopersistence assay. Based on the results of such assay, fibers can be classified into one of two categories: a biopersistent fiber that cannot be dissolved in the lung within an acceptable time period; or a biosoluble fiber when even long nonphagocytizable fibers will be disappearing rapidly from the lung. However, in addition to biopersistence, it should be mandatory to evaluate fiber toxicity in an appropriate assay relative to a fiber whose long-term effects are well known. Moreover, for organic fibers it is likely that different rules may have to be established for characterization of their toxic and carcinogenic potential. 相似文献
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头孢菌素产生菌顶头孢霉菌株229的沉没培养或斜面培养都可形成分生孢子,并可用普通滤纸将它们与菌丝及节孢子分开,但是它们成活率极低.这种成活的分生孢子的数量与培养基成分有关.菌丝培养基成分对制备顶头孢霉原生质体有显著影响.用一种MM培养基培养的菌丝,不经巯基化合物预处理,酶解(1%纤维素酶)3小时后,可得到大量原生质体.原生质体的再生频率为1.8~4.6%.与分生孢子形成的菌落相比,原生质体再生菌落的产抗生素能力显示出较大的变异性.本文还讨论了山梨醇与Nikkomycin对菌丝生长形态及原生质体形成的影响. 相似文献
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Yuhei Kawano Kaoru Yoshida Minoru Kawamura Hiroki Yoshimi Terunao Ashida Hitoshi Abe Masahito Imanishi Genjiro Kimura Shunichi Kojima Morio Kuramochi Teruo Omae 《Clinical and experimental pharmacology & physiology》1992,19(4):235-241
1. The effects of dietary sodium on blood pressure and levels of sodium, other electrolytes and noradrenaline (NA) in the cerebrospinal fluid (CSF) and blood of 15 patients with essential hypertension were studied. The CSF and blood sampling was carried out after 7 days of a high salt intake (16-18 g/day) and after 7 days of a low salt intake (1-3 g/day). 2. Blood pressure and sodium concentrations in CSF and serum were significantly higher in the high salt period than the low salt period (CSF Na+ concentration: 147.7 +/- 0.4 mmol/L vs 145.3 +/- 0.5 mmol/L; P less than 0.001). Levels of CSF pressure and potassium or calcium concentrations were not different between the two periods. Plasma NA and plasma renin activity (PRA) were lower and CSF NA levels tended to be lower in the high salt period. 3. The levels and the changes in sodium and NA in CSF were not significantly different between the salt-sensitive (n = 8) and the non-salt-sensitive (n = 7) subjects, but the changes in plasma NA and PRA were smaller in the salt-sensitive subjects. 4. These results indicate that the sympathetic nervous system is less suppressed in salt-sensitive subjects during high salt intake. This may be due to altered neural responsiveness to sodium loading rather than being greater increases in sodium concentration in the central nervous system. 相似文献
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B. K. H. Tan J. S. Hutchinson 《Clinical and experimental pharmacology & physiology》1987,14(10):797-803
1. The effects on blood pressure (BP) and plasma and pituitary prolactin (PRL) of a 13 day intraperitoneal infusion of bromocriptine delivered by osmotic minipump were investigated in spontaneously hypertensive rats (SHR) and their normotensive controls, the Wistar-Kyoto rats (WKY). 2. In the SHR, a fall in BP which was steepest over the initial few days and sustained up to day 12 was observed in the bromocriptine-treated group compared with the lack of a change in BP observed in the vehicle-treated group. The plasma PRL level taken on day 13 was found to be significantly lower in the bromocriptine-treated group than in the vehicle-treated group. 3. In the WKY, bromocriptine had no significant effect on either BP or plasma PRL. 4. Pituitary PRL content was significantly lower in the SHR than in the WKY. The suppression by bromocriptine treatment was greater in the SHR than in the WKY. 5. These results provide further evidence for a central dopaminergic insufficiency in the SHR and raise the possibility that PRL may, either directly or indirectly by interacting with other factors in the SHR, influence BP. 相似文献
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《Clinical Research and Regulatory Affairs》2013,30(1):67-81
ABSTRACTAs online healthcare delivery gains momentum in the new millennium, it is going to pose greater challenges for the regulators internationally so that the consumer's best interest is maintained. It will become increasingly important to identify and inform consumers regarding reputable websites that can address some health-related issues for the consumer. This paper discusses some of the evolving issues and dilemmas facing private sector companies, Internet advertisers, and government regulatory agency's role in promoting public health and safety. Some of the challenges involved in cultivating the benefits of electronic commerce, while at the same time preventing abuse, fraud, and deceptive and dangerous online practices, are also explored.The paper outlines some of the early efforts of regulatory bodies, particularly the Food and Drug Administration (FDA), to keep abreast of rapidly changing developments and complex issues involved in the growth of “internet pharmacies.” In part, this paper offers a snapshot of the unruly, chaotic birth and nascent development of both an industry and a technology that threaten to outrun the ability of the law and public agencies to monitor and regulate. Some of the issues related to online healthcare delivery are also discussed. 相似文献
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MEASUREMENT AND IDENTIFICATION OF PRORENIN AND RENIN IN OVARIAN FOLLICULAR FLUID FROM CATTLE AND PIG
Arne Hagemann Arne Høj Nielsen Vibeke Dantzer Birthe Avery Knud Poulsen 《Clinical and experimental pharmacology & physiology》1992,19(4):267-273
1. In previous studies we have demonstrated and solved several methodological problems in relation to the measurement of prorenin by trypsin activation in rat, bovine, hog and horse plasma. 2. The aim of the present study was to develop a method for the measurement of prorenin in bovine and porcine ovarian follicular fluid. 3. Trypsin activation of follicular fluid generated angiotensin I immunoreactive material (AI IM) in both species. 4. The AI IM interfered with the renin assay, but could be completely removed by a cation exchange resin in a batch-wise technique. 5. The enzymatic activity of trypsin-activated prorenin and pre-existing active renin was completely inhibited by a specific inhibitor of renin. 6. The reactions were optimized and an accurate measurement of prorenin in ovarian follicular fluid was developed. 7. The existence of prorenin and renin in bovine ovarian follicular fluid was established. Prorenin and renin in porcine ovarian follicular fluid was demonstrated for the first time. 8. The ratio between ovarian follicular fluid and plasma was 43 for prorenin and 19 for active renin in cattle. The same ratios in pigs were 1.3 and 0.4, respectively. These findings indicate a species difference with respect to the amount of prorenin or active renin present in ovarian follicular fluid. 相似文献
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1. The effects of acute and chronic treatment of methaqualone on ethanol preference, the rate of disappearance of ethanol and on toxicity were studied in mice and rats. 2. Acute treatment with methaqualone showed a dose-dependent suppression in the voluntary intake of ethanol in C57B1/6J mice and rats. No significant change in ethanol intake was observed during chronic methaqualone treatment and withdrawal. 3. Methaqualone pretreatment significantly (P < 0.005) delayed the disappearance of ethanol in the blood and brain over a period of 50 to 200 min after a loading dose of 2.0 g/kg, i.p., of ethanol. 4. Methaqualone pretreatment at doses of 140 and 200 mg/kg significantly increased ethanol toxicity by 11% and 28%, respectively. Co-administration of ethanol using 6.0, 7.0 and 8.0 g/kg also reduced the LD50 of methaqualone by 19%, 24% and 40%, respectively. 5. Chronic administration with ethanol decreased the toxicity due to methaqualone. Potentiation of ethanol toxicity by methaqualone may be of clinical importance in view of the narrow range of safety margin of ethanol. 相似文献