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Biomedical subjects

H O COLLIER

Publications and source records attributed to H O COLLIER.

At least 37 records · Page 2Linked to original sources
PubMed1959

Assay of suxamethonium and laudexium on the frog rectus abdominis.

Suxamethonium, like acetylcholine, causes contracture of the isolated rectus abdominis muscle of the frog, whereas laudexium antagonizes this effect. These actions may be used to assay both drugs with reasonable speed and fiducial limits, provided that changes in responsiveness of the preparation during the course of assay are met by suitable design and analysis. Small quantities of suxamethonium and laudexium may be assayed in certain body fluids.

Acetylcholine↗
PubMed1958

Local action of some antibacterial substances against Corynebacterium ovis in guinea-pig skin.

When a suspension of living Corynebacterium ovis was injected intradermally in guinea-pigs, a lesion of roughly circular outline developed within 24 hr. Lesions of smaller diameter arose if benzylpenicillin, dequalinium, hedaquinium, cetrimide, or oxytetracycline were injected at the identical site, either before, with, or after C. ovis. Evidence has been obtained that such reductions of lesion diameter are due to direct action of drugs on bacteria and not to antitoxic or anti-inflammatory actions. Lesion diameters became less as drug dosage increased up to a limit, and these reductions provided a measure of local antibacterial action in vivo. Intradermal injection of higher concentrations of antibacterials, without C. ovis, produced comparable but somewhat flatter lesions, diameters of which increased with increasing concentration of drug and provided a measure of intradermal toxicity.

Animals↗
PubMed1957

Detection and measurement of antagonism to folic acid.

Methods of testing competitive antagonism in bacterial systems are considered and evaluated with particular reference to antifolic acids. Four antifolic acids-pteridine O/129, methotrexate, CB2295 and CB2335-were examined for competitiveness and potency in three test systems-Leuc. citrovorum and folinic acid, Str. faecalis and folinic acid, and Str. faecalis and pteroylglutamic acid. For comparison, phenol and formaldehyde were studied in the Leuc. citrovorum and folinic acid system. Interpretation of results was based on families of log. concentration/growth curves obtained in each system in the presence and absence of each antagonist. These curves were usually simple sigmoids. From these families of curves, pA values were derived and reciprocal growth/reciprocal concentration curves were drawn. Pteridine O/129 was fully competitive in all systems, while methotrexate was fully competitive in the Str. faecalis and folinic acid system, but did not give simple sigmoids in the other two systems. CB2295 showed some competitive features in all and CB2335 in the two systems in which it was active. It is concluded that the methods adopted, based on those used in vertebrate pharmacology, provide a stringent test of competitiveness in bacterial systems.

Folic Acid↗