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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Inflammation research 45 (1996), S. 531-540 
    ISSN: 1420-908X
    Keywords: Antiinflammatory ; Analgesic ; Antipyretic ; pKa ; Octanol-water partition coefficient ; NSAIDs ; Animal models ; Carrageenin ED50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective and Design: Relevance of the preclinical pharmacodynamic, toxicity and pharmacokinetic parameters predicting the clinical potency of nonsteroidal antiinflammatory drugs (NSAIDs) was evaluated. Material: Data for oral potencies of 24 NSAIDs in rats were collected from the literature and from New Drug Applications with respect to the following parameters: antiinflammatory, analgesic, antipyretic, acute ulcerogenic activities, acute toxicity, in vitro inhibition of prostaglandin synthesis, acid dissociation constant (pKa), octanolwater partition coefficient and elimination half-life. Treatment: Data for most of the in vivo parameters in rats were collected following single dose administration with the exception of adjuvant arthritis. Single and daily clinical doses were considered. All of these NSAIDs have been approved for marketing although not all have been sold in the USA. Methods: The preclinical data were compared to human dose (unit or daily doses) using single and multiple stepwise regression analyses. Results: Analyses suggest that NSAIDs are effective in all models of preclinical tests for fever, pain and inflammation, however, carrageenin-induced rat paw edema model is clearly the best predictor of human dose. Rank order of preclinical models for predicting human dose is carrageenin 〉yeast induced fever〉pressure induced pain=adjuvant arthritis in rats. The analysis suggested that the pain and adjuvant arthritis models in rats may also involve a prostaglandin independent mechanism. Of the two physicochemical factors tested, pKa contributed best to the carrageenin model towards predicting the clinical potency of NSAIDs. Mathematical relationships between human dose, carrageenin ED50 and pKa were established that may assist in the future clinical development of NSAIDs. Conclusions: Carrageenin-induced paw edema model in rats is the most robust predictor of the clinical potency of NSAIDs. Acid dissociation constant (pKa) appears to be a secondary contributor to the potency of NSAIDs. The relevance of the data analyses for developing cyclooxygenase-2 (COX-2) selective NSAIDs is discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-675X
    Keywords: Apoptosis ; bcl-2 ; dopamine ; Parkinson's disease ; PC-12 ; proto-oncogene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract It is currently believed that excessive oxidant stress induced by metabolism of dopamine (DA), plays a major role in the pathogenesis of the selective nigrostriatal neuronal loss in Parkinson's disease. We recently showed that the neurotransmitter DA, in physiological concentrations, is capable of initiating apoptosis in cultured, post-mitotic sympathetic neurons. Bcl-2 is a proto-oncogene that blocks apoptosis. We now report that Bcl-2 is a powerful inhibitor of DA toxicity in PC-12 pheochromocytoma cells. We induced stable expression of Bcl-2 in PC-12 cells by transfection with recombinant pCMV5 expression vector, containing mouse bcl-2 (coding-sequence) cDNA. Cells expressing Bcl-2 manifested marked resistance to otherwise lethal (300 uM) in vitroconcentrations of DA. This protective effect was reflected in the trypan-blue test of cell survival, 3 H-thymidine incorporation and inhibition of the characteristic apoptotic morphologic alterations in scanning electron microscopic studies. Bcl-2 and associated control systems of apoptosis may have an important physiological role in restraining the apop-tosis-triggering potential of DA in nigrostriatal neurons. This novel field of research may yield insights into the pathogenesis of Parkinson's disease and lead to development of novel therapeutic approaches.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular neurobiology 17 (1997), S. 289-304 
    ISSN: 1573-6830
    Keywords: Parkinson's disease ; dopamine ; dopamine-melanin ; apoptosis ; bcl-2 ; antioxidants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. Degeneration of nigrostriatal dopaminergic neurons is the major pathogenic substrate of Parkinson's disease (PD). It is assumed that the lethal trigger is the accumulation of oxidative reactive species generated during metabolism of the natural neurotransmitter dopamine. 2. We have recently shown that dopamine is capable of inducing programmed cell death (PCD) or apoptosis in cultured postmitotic chick sympathetic neurons and rat PC12 pheochromocytoma cells. 3. The bcl-2 gene encodes a protein which blocks physiological PCD in many mammalian cells. In an attempt to elucidate further the mechanism of dopamine toxicity, we examined the potential protective effect of bcl-2 in PC12 cells which were transfected with the protooncogene. 4. In our experiments, Bcl-2 producing cells showed a marked resistance to dopamine toxicity. The percentage of nuclear condensation and DNA fragmentation visualized by the end-labeling method following dopamine treatment was significantly lower in bcl-2 expressing cells. Bcl-2 did not protect PC12 cells against toxicity induced by exposure to dopamine-melanin. Extracts of PC12 cells containing Bcl-2 inhibited dopamine autooxidation and formation of dopamine-melanin. Furthermore, the presence of Bcl-2 protected cells from thiol imbalance and prevented thiol loss following exposure to dopamine. 5. The protective effects of Bcl-2 against dopamine toxicity may be explained, in part, by its action as an antioxidant and by its interference in the production of toxic agents. The possible protection by Bcl-2 against neuronal degeneration caused by dopamine may play a role in the pathogenesis of PD andmay provide a new direction for the development of neuroprotective therapies.
    Type of Medium: Electronic Resource
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