ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00325.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The primary physiological mode of action of nearly all drugs used to control helminth parasites is not well understood. Examination of the general modes of action in terms of parasite requirements for survival may, however, provide guidelines to continue our present investigations and direct us for future research.Two general areas of drug activity are (1) interference with energy‐generating metabolism, and (2) interference with proper neuromuscular coordination. Few exceptions are found to these areas because the target organisms require little else for survival.The target of most previously effective and many presently effective anthelmintics is an adult parasite. Adult helminth parasites must maintain an advantageous feeding site and must transport and metabolize substrates (primarily glucose) to generate life‐maintaining energy. Adult worms have almost no other short‐term requirements for survival because they have little or no metabolic activity in either lipid synthesis or oxidation, nucleic acid synthesis, or protein synthesis (except egg‐laying).Examination of specifics of energy‐generating metabolism and putative neurochemical transmitters allows us certain predictions in relating a given drug activity to an individual species. These examinations indicate that such diversity exists among helminth metabolic or nervous systems that a broad‐spectrum anthelmintic would most likely inhibit at several sensitive points.Published information on drug action and differences in data interpretation are discussed. Two novel areas for future anthelmintic investigations may be (1) juvenile hormone or ecdysone analogs, and (2) pheromones. A combined empirical and rational approach to the development of new drugs may be the most efficient avenue of futu

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00326.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A total of forty‐eight dogs were utilized to titrate and evaluate the activity of a new miticide, amitraz. The treatment was applied dermally and evaluated for efficacy against experimentally inducedDemodex canisandSarcoptes scabieiinfestations. Five different concentrations (2000, 1000, 500, 250, 125 p.p.m.) of the active drug, N'—(2, 4‐dimethylphenyl)N—{[(2, 4‐dimethylphenyl) imino] methyl} ‐N‐methyl‐methanimidamide, were tested. The activity of amitraz was compared to a standard treatment, placebo treatment, and no treatment.A single dermal treatment with amitraz (all concentrations) indicated activity against bothD. canisand S. scabiei. The lowest concentration of active drug (125 p.p.m.) was significantly less efficacious than the four higher concentrations (250, 500, 1000, 2000 p.p.m.). At the 250 p.p.m. (or higher) level the effectiveness of this new miticide was comparable to the standard treatment. The data indicate the 250 p.p.m. concentration is the optimal level and the recommended dilution for treatment of mange mites. Drug reactions related to amitraz we

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00327.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Cerebral blood flow (CBF) was measured in sheep by measuring clearance of directly injected133Xenon from the cerebral cortex. The influence of ketamine at various dose levels on the CBF was measured and compared to the effects produced by pentobarbitone and CT1341. It was found that ketamine caused an initial depression of CBF followed by a rise, pentobarbitone produced a profound long lasting depression whilst CT1341 caused an initial depression which was rapidly followed by a return to control values.

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00328.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Thein vitroinactivation of crude endotoxins (lipopolysaccharides) of fourEscherichia colistrains by polymyxin B and colistin in mastitic milk was investigated utilizing theLimulusamebocyte lysate test. Although minor differences were observed among the endotoxins in respect to susceptibility to inactivation, activity of each was markedly reduced by both drugs.

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00329.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The ulcerogenic and secretogenic properties of betazole, (an H2agonist), and/or reserpine on pig stomachs were studied. (1) Betazole (50 mg/body) and reserpine (0.02 mg/kg) were successively injected (i.m.) for 5–10 days into starved animals. Gastroesophageal ulcers, pathologically similar to naturally occurring ulcers were observed in all pigs (10/10), whether a nutrient solution (5% glucose, 1 litre/day) was supplied or not. In the starved pigs given either betazole or reserpine, only a small ulcer or erosion was observed. (2) In four pigs which were given commercial mash at a rate of 3% of body weight per day and killed on the 6th or 10th day of successive injections of both drugs, the incidence of ulcers was 2/4. (3) The gastric secretogenic effect of betazole and/or reserpine was confirmed in pigs with Heidenhain gastric pouches. (4) From these data, a new method for the experimental induction of pig gastroesophageal ulcers, by means of simultaneous injections of betazole and reserpine for 5 days under the nutrient (glucose solution) drinking condition, is proposed. The authors consider that this method may be superior to the repository histamine method, with respect to the absence of adverse effects, practical convenience and pathological and etiological similarities with naturally occurring ulcer

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00330.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The changes induced in the electrical activity of the small intestine by atropine sulphate, diphemanil methylsulphate, hyoscine butylbromide and prifinium bromide were studied in conscious sheep fitted with chronically implanted electrodes. Increased spike potential activity was induced by carbachol. The mean slow‐wave frequency of the antrum was 7.35 ± 0.18/min with burst of spike potentials randomly superimposed on about 63% of the slow waves. The occurrence of the spike bursts was inhibited for 18—30 min after an intravenous injection of atropine (0.75 mg/kg) and during its infusion at the rate of 0.05 mg/kg/min. The activity of the proximal part of the small intestine, which is characterized by migrating myoelectric complexes moving down slowly at hourly intervals, was replaced by irregular series consisting of spike bursts of about 3 min duration, at intervals of about 12 min for a total of 110 min. Such an effect, in which the level of spike activity was reduced, was also observed with hyoscine, diphemanil and prifinium during 80, 120 and 180 min periods respectively. The injection of carbachol was followed by continuous spike activity in which the mean spike level was nearly doubled, as occurs at the onset of diarrhoea. An inhibitory effect was observed at both antral and duodeno‐jejunal levels with the four drugs used, that of hyoscine being least marked. The effect of prifinium was more pronounced than that of atropine or diphemanil, especially on the jejunum. The results suggest that the ability of these drugs to reduce the level of spike activity accompanying disruption of migrating myoelectric complexes and to inhibit the carbachol‐induced increased level of spiking may account for the antispasmodic effects observed after the use of anticholinergic drugs in gastrointestinal disorders. Prifinium had the longest lasting effect at both antral and duodeno‐jejunal levels and seemed to be a good atropine substitute to alleviate gastro‐intestinal h

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00331.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The tissue distribution of tetraethylammonium (TEA), a highly polar drug which does not undergo biotransformation, was studied in intact and nephrectomized dogs and goats. Values for β, the overall elimination rate constant, were significantly reduced by nephrectomy but species differences were not significant. Values for apparent specific volume of distribution (V'd) were unexpectedly large and tissue to plasma ratios were 4.0 and 5.0 in the nephrectomized goat and dog, respectively. The distribution of TEA to various tissues followed closely the expected pattern of regional blood flow, although TEA attained concentrations in liver, heart, lungs and viscera in excess of the concentration in the plasma

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00332.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00333.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1978.tb00334.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY