Cytotoxic action

Many of the toxins obtained from coelenterates and echinoderms, because of their hemolytic or cytotoxic actions, are assumed to have a general disruptive action on cell membranes. However, since many of these toxins are capable of forming pores or channels in the plasma membrane of cells, their cytolytic actions may be a result of this highly selective action. On the other hand, the saponins from starfish and sea cucumbers have a direct lytic action as a result of their detergent action on the integrity of cells. 

H and HD are blister and alkylating agents, producing cytotoxic action on the hematopoietic (blood-forming) tissues. The rate of detoxification of H and... 

HD is a vesicant (blister agent) and alkylating agent producing cytotoxic action on the hematopoietic (blood-forming) tissues which are especially sensitive. The rate of detoxification of HD in the body is very slow, and repeated exposures produce a cumulative effect. It causes blisters, irritates the eyes, and it is toxic when inhaled. HD has been determined to be a human carcinogen by the International Agency for Research on Cancer. 

Mata, J. F., et al. Role of the human concentrative nucleoside transporter (hCNTl) in the cytotoxic action of 5[Prime]-deoxy-5-fluorouridine, an active intermediate metabolite of capecitabine, a novel oral anticancer drug. Mol. Pharmacol. 2001, 59, 1542— 1548. 

Obrig TG, Del Vecchio PJ, Brown JE, Moran TP, Rowland BM, Judge TK, Rothman SW Direct cytotoxic action of Shiga toxin on human vascular endothelial cells. Infect Immun 1988 56 2373-2378. 

Another amino acid taurine (Figure 29.21) is an effective scavenger of hypochlorous acid, which is known to participate in tissue damage associated with reperfusion injury mediated by neutrophils. Thus, taurine protected against the cytotoxic action of HOC1 in neuronal cells... 

Dick et al. [88] studied the antioxidant effects of NADPH-dependent alkenal/one oxidor-eductase (AO), also known as leukotriene B4 12-hydroxydehydrogenase, 15-oxoprostaglan-din 13-reductase, and dithiolethione-inducible gene-1. It was found that AO catalyzed the hydrogenation of many a,(3-unsaturated aldehydes and ketones and protected against cytotoxic action of 4-hydroxy-2-nonenal. 

The answer is c. (Hardman, p 15230 Administration of intravenous CaG would immediately correct the tetany that might occur in a patient in whom a thyroidectomy was recently performed. Parathyroid hormone would act more slowly but could be given for its future stabilizing effect. Long-term control of a patient after a thyroidectomy can be obtained with vitamin D and dietary therapy Calcitonin is a hypocalcemic antagonist of parathyroid hormone. Plicamycin (mithramycin) is used to treat Paget s disease and hypercalcemia. The dose employed is about one-tenth the amount used for plicamycin s cytotoxic action. 

A dose-related depression in testosterone production at doses not producing any general toxic or significant cytotoxic action... 

Chalcones (including 11) contain a l,3-diaryl-a,/)-unsaturated ketone moiety and have anti-cancer properties [38]. As analogs of CA-4, 7, the mode of cytotoxic action of chalcones has been shown to be similar to the com-bretastatins. They bind to the colchicine site of tubulin and inhibit tubulin polymerization [39]. 

A number of reports, both old and recent, describe antiviral, antimicrobial, an-tiparasitic, and antitumoral properties of a number of furoxan derivatives [7, 11, 12]. Since it is known that nitric oxide displays potent cytotoxic actions in the immune... 

Eropkin MYu, Eropkina EM, Kiselev OI (2007) Studying the effect of antioxidants and/or anti-hypoxants on cell cultures under conditions of cytotoxic action of rimantadine. Exp Clin Pharmacol. 70 56-61 (Russian). 

Umata T, Moriyama Y, Futai M, Mekada E. The cytotoxic action of diphtheria toxin and its degradation in intact Vero cells are inhibited by bafilo-mycin Al, a specific inhibitor of vacuolar-type H(+)-ATPase. J Biol Chem 1990 265(35) 21940-21945. 

The first step of this sequence, which is not unique to de novo purine nucleotide biosynthesis, is the synthesis of 5-phosphoribosylpyrophosphate (PRPP) from ribose-5-phosphate and adenosine triphosphate. Phosphoribosyl-pyrophosphate synthetase, the enzyme that catalyses this reaction [278], is under feedback control by adenosine triphosphate [279]. Cordycepin interferes with thede novo pathway [229, 280, 281), and cordycepin triphosphate inhibits the synthesis of PRPP in extracts from Ehrlich ascites tumour cells [282]. Formycin [283], probably as the triphosphate, 9-0-D-xylofuranosyladenine [157] triphosphate, and decoyinine (LXXlll) [284-286] (p. 89) also inhibit the synthesis of PRPP in tumour cells, and this is held to be the blockade most important to their cytotoxic action. It has been suggested but not established that tubercidin (triphosphate) may also be an inhibitor of this reaction [193]. 

Etoposide and teniposide are synthetic derivatives of the extract of the American mandragora plant (May Apple). The mechanism of their action has not been completely explained however, they act on the enzyme topoisomerase II, which disturbs the twisting of DNA. In addition, they inhibit DNA and RNA synthesis, as well as transport of nucleotides to cells. Cytotoxic action on normal cells is observed only in very high doses. These drugs exhibit significant activity in lymphomas, leukemia, Kaposi s sarcomas, and in testicular cancer. 

Hormonal drags do not cure cancer, although they do exhibit pronounced palliative action, with the exception of the cytotoxic action of glucocorticoids on lymphoid cells. In particular, this concerns predinsone, which is used to treat lymphomas and certain leukemias in combination therapy. 

Chibber R. Radiosensitizing and cytotoxic action of some Rh(II) carboxylates in vitro a comparison with Pt(II) complexes. Ph.D. Dissertation 1984 Department of Chemistry, Hatfield Polytechnic, Hatfield, Hertfordshire, England. 

Kohn KW, Pommier Y. Molecular and biological determinants of the cytotoxic actions of camptothecins. Perspective for the development of new topoisomerase I inhibitors. Ann NY Acad Sci 2000 922 11-26. 

The cytotoxic action of Glyo II was thus elixsidated by its reaction with RSH. 

A number of organs are affected adversely by chronic ethanol use, the result of a direct cytotoxic action. Hepatic fatty infiltration and cirrhosis are common... 

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