PubMed Health⌕ Search

Biomedical subjects

Z Tashma

Publications and source records attributed to Z Tashma.

11 recordsLinked to original sources
PubMed2001

Bretazenil, a benzodiazepine receptor partial agonist, as an adjunct in the prophylactic treatment of OP poisoning.

Benzodiazepines, mainly diazepam, are commonly used as anticonvulsants in the treatment of organophosphate casualties. Although very effective, diazepam usually is not used in prophylactic treatments because of its adverse effects on task performance and its abuse liability. Benzodiazepine (BZ) partial agonists are unique in that they are able to occupy all the population of a given receptor without eliciting the maximal physiological response. The BZ receptor agonistic occupancy was found to differ among the various physiological responses in the following order: antipanic > anticonvulsion > sedation > muscle relaxation. Thus, partial agonists, by the use of which controlled levels of agonistic activity can be achieved, might serve as effective anticonvulsants, with fewer side-effects. Bretazenil, a partial agonist, was found to counteract metrazol-induced convulsions in rats. At the anticonvulsive doses (125-250 microg x kg(-1), i.p.) bretazenil, in combination with pyridostigmine (100 microg x kg(-1), i.m.) and aprophen (4 mg x kg(-1), i.m.), conferred prophylactic protection against sarin and soman poisoning (protective ratios 2.6 and 2.1, respectively). Relevant doses of bretazenil (50-400 microg x kg(-1), i.p.) also were tested for general behavioural effects in the open field and for its anti-anxiety properties in the plus maze. The incapacitation was much lower compared with diazepam. Bretazenil should be considered as a candidate for incorporating into a prophylactic mixture as a central nervous system protectant, with significant advantages concerning incapacitation.

Animals↗
PubMed1996

Catalytic antibodies: generation, nature, and possible role as chemical warfare scavengers.

Nearly three decades have passed since the idea was proposed that antibodies may provide catalytic activity as enzymes. Since then the term "catalytic antibodies" has gained more and more popularity. Numerous antibodies enhancing the rate of reactions have been described. This review will address the basic biological considerations involved in the genesis of catalytic antibodies and explore their possible role in the future providing protection in chemical warfare.

Antibodies, Catalytic↗
PubMed1989

The effect of substituted aminoalkylaminoanthraquinones on eukaryotic cells.

Nine aminoalkylaminoanthraquinones (I-IX) were evaluated for their cytotoxic potency against normal and malignant mammalian cells. The 1.8-di-(aminopropylamino) derivative (VIII) exhibited significant activity against several tumor cell systems and had some selectivity. The toxicity of this compound was also tested in growing chick embryos.

Animals↗
PubMed1987

Zwitterionic analogues of cimetidine as H2 receptor antagonists.

A series of analogues of the H2 receptor histamine antagonist cimetidine have been synthesized in which the dipolar cyanoguanidine group has been replaced by a number of zwitterionic moieties. Although none of the compounds is more effective than cimetidine in blocking histamine-stimulated tachycardia on the isolated guinea pig atrium, the activities of most of the compounds possessing rigid dipoles can be accounted for on the basis of dipole orientation relative to the common side chain and by considering the active species in each case to be the zwitterion. These findings are in general agreement with those found for analogues having conjugated groups as dipoles.

Animals↗
PubMed1986

Reaction of cimetidine with Fenton reagent. A biomimetic model for the mixed-function oxidase drug metabolism.

Cimetidine sulfoxide, N-desmethylcimetidine, N-desmethylcimetidine sulfoxide, cimetidine guanylurea, and the 5-hydroxymethylimidazole derivative of cimetidine sulfoxide were isolated from the reaction of cimetidine with Fenton reagent. The product distribution from the reaction of cimetidine with Fenton reagent clearly simulates the metabolism of cimetidine by the mixed-function oxidase.

Cimetidine↗
PubMed1984

Nmr study of theophylline-ethylenediamine interaction in aqueous solution.

The behaviour of the H(8) nmr signal of theophylline in D2O solutions containing various amounts of ethylenediamine, indicates that in no case is the latter doubly charged, and so at an ethylenediamine to theophylline molar ratio of 0.5 (corresponding to that found in aminophylline) about half of the theophylline is present in a non-ionic form. At higher ratios an increase in its degree of ionization occurs, as evident from the continued upfield shift of the H(8) signal. The behaviour of the N-methyl signals differed from that of H(8). As the proportion of ethylenediamine increased from zero to 1.2 times that of theophylline, these signals first shifted upfield, but then moved back to approximately their initial positions. It is suggested that at low ratios, including that in aminophylline, the solution is composed of monocations of ethylenediamine paired to negatively charged aggregates of theophylline, in which both neutral molecules and ions co-exist. The ions thus act as solubilizing agents for the neutral, and usually slightly soluble, form of theophylline. At high ethylenediamine to theophylline ratios, the latter is fully ionized and the aggregates disintegrate.

Chemical Phenomena↗
PubMed1983

The effect of diaminoalkyl-anthraquinone derivatives on the growth of the promastigotes of Leishmania tropica minor, L. t. major, L. donovani and L. aethiopica.

By combining knowledge of polyamine biosynthesis and its inhibition by various analogues with that on the activity of synthetic anthraquinones, a series of six anthraquinone derivatives were synthesized. Their ability to inhibit the growth of leishmanial promastigotes in vitro was used as a preliminary screen to check their potential as new antileishmanial chemotherapeutics. They were tested against four strains, representing four different species; Leishmania tropica major, L. tropica minor, L. aethiopica and L. donovani, associated with four separate disease syndromes. All six derivatives exhibited a fair degree of antileishmanial activity, some being more effective than others. They all inactivated cultures at 100 micrograms/ml and some did so at 10 micrograms/ml and even 1 microgram/ml; but taking different lengths of time to achieve this. Antileishmanial activity associated with anthraquinone derivatives might provide a new approach to the chemotherapy of leishmaniasis.

Anthraquinones↗
PubMedDate not supplied

Creatine kinase activity decrease with short-term freezing.

Freezing of serum samples at -30 degrees C without protective agents is the simplest and least expensive method of storage in serum banks. We investigated the stability of creatine kinase (CK) in human sera after freezer storage under such conditions for 24 h (n = 30) or for 2 or 4 weeks (n = 99). CK activity was measured in fresh sera and compared to matched thawed sera after freezer storage at the designated time intervals. The enzyme's median activity decreased significantly after 24 h, 2 weeks, and 4 weeks of freezer storage by 2.6, 5.9, and 8.3%, respectively (p < 0.0001, r = 0.99). Sex or high CK initial values had no significant effect on these results. We conclude that freezer storage of serum at -30 degrees C, even for short periods, causes a steady and significant decline in CK activity. These results should be taken into consideration when analyzing CK activity in frozen sera for research or clinical purposes.

Blood Banks↗