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A J Hedges

Publications and source records attributed to A J Hedges.

25 records · Page 2Linked to original sources
PubMed1967

Kinetics of lethal adsorption of colicin E-2 by Escherichia coli.

The kinetics of lethal adsorption of colicin E2 by Escherichia coli C6 were studied by means of survivor plots. These were determined by a method which allowed rapid sampling of the reaction mixture and estimation of approximate confidence limits for the plotted data. The results were consistent with the predictions of a hypothetical model that assumed a single-hit mechanism of colicin action upon a bacterial population whose cells varied in their number of specific (lethal) receptors for colicin. The possibility of nonlethal adsorption is discussed.

Adsorption↗
PubMed1965

Daily penicillin serum concentrations following injection of 1.2 mega-units of "all-purpose" penicillin.

In view of evidence suggesting that 1.2 mega-units of "all-purpose" penicillin (300 000 IU potassium penicillin G, 300 000 IU procaine penicillin G and 600 000 IU benzathine penicillin) did not maintain treponemicidal serum concentrations during the week following injection-which if true, might necessitate a reappraisal of prophylactic and treatment schedules in wide use against syphilis-daily assays were performed to determine the penicillinaemia levels in ambulant adult males for one week following intramuscular injection with this dosage of two "all-purpose" products (168 assays in all, 24 each day).Statistical evaluation of the results showed that the mean daily serum concentrations were, in fact, treponemicidal during the whole week after injection. The means of groups of 24 assays fell within narrow daily ranges on each of the seven post-injection days, suggesting that the long-acting component (benzathine penicillin) gives reliable and predictable daily levels in a high proportion of cases. This is in contrast to those penicillins which rely for their long-acting property on the oily gel in which they are suspended. On the other hand, the extremes of penicillinaemia for any individual in a large group were shown to cover a very wide range, demonstrating that a particular patient's failure to respond to standard treatment or prophylaxis can be due to factors quite unrelated to the quality or specificity of the product or to the sensitivity of the organism causing disease.

Adult↗