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Biomedical subjects

M L McConville

Publications and source records attributed to M L McConville.

5 recordsLinked to original sources

Matching training procedures to outcomes. A behavioral and quantitative analysis.

To analyze the effects of matching the prompting procedure used in training to the specific behavior chain to be taught, 3 students with mild to moderate retardation were taught four independent tasks: making a bagged lunch, playing a matching game with a peer, ordering food at a restaurant, and participating in a social conversation. Following baseline, all 3 students were exposed to one of two types of training procedures for each task: a least-to-most prompting procedure or a most-to-least prompting procedure. The type of training procedure was counter-balanced across students and tasks, whereas performance on the tasks was evaluated within a combination of a multiple-baseline design across participants and multiple-probe design across tasks. When the method of prompting was matched to the naturally occurring discriminative stimulus (SD) of the training stimulus, it greatly affected acquisition and maintenance of the skill in terms of differences in levels of and variability of performance. The most-to-least method of prompting, the matched method in these cases, was more efficient and effective for acquisition and generalization of the bagged-lunch and matching-game skills. The least-to-most method, the matched method in these cases, was more efficient and effective for social questions and ordering-food skills.

Activities of Daily Living↗

Effects of sarafloxacin hydrochloride on human enteric bacteria under simulated human gut conditions.

The effects of sarafloxacin, a newly developed veterinary fluoroquinolone antimicrobial, on 15 strains of aerobic and anaerobic bacteria of human origin were assessed under simulated human gut conditions. An in vitro gut simulation model was designed to mimic the situation of sarafloxacin (free and bound to meat) passing through the human gastrointestinal tract. The survival of bacteria in the simulation model and any subsequent change in the sensitivity of isolates to sarafloxacin were measured. The inhibitory level of sarafloxacin for the tested bacteria was strain dependent. It appeared that in broth culture Escherichia coli isolates were sensitive to sarafloxacin concentrations 5-fold lower than the concentrations present in the simulated gut model, suggesting that sarafloxacin may be partially unavailable due to absorption to organic matter in the model. There was no significant observed change in the sarafloxacin sensitivity of the bacterial strains exposed to the compound in the model.

Animals↗

Mutants of Escherichia coli K12 accumulating porphobilinogen: a new locus, hemC.

Mutants of Escherichia coli K12 which accumulated the haem precursor porphobilinogen are described. The mutants grew very slowly on carbon and energy sources which K12 uses only oxidatively, and they had low catalase activities, suggesting that they were deficient in haem. Extracts had one-tenth of the parental activity of the enzyme porphobilinogen deaminase. In transduction, the mutation mapped close to genes ilvD and metE at minute 84. The gene was tentatively identified as hemC, coding for porphobilinogen deaminase. The gene symbol hemC replaces the earlier and temporary symbol popE.

Chromosome Mapping↗

Isolation of haemin-requiring mutants of Escherichia coli K12.

Fifty-five haemin-requiring mutants were isolated from haemin-permeable mutants. According to their growth responses to haem precursors and their patterns of porphyrin accumulation, the 55 mutants fell into three groups which were judged to have defects in 5-aminolaevulinate dehydratase, ferrochelatase, and uroporphyrinogen III cosynthase or uroporphyrinogen decarboxylase. In mutants of the group deficient in 5-aminolaevulinate dehydratase, the mutations were adjacent to lac, and evidence is presented that the mutations were in hemB and were commonly deletions extending into proC.

Aminolevulinic Acid↗

Mutants of Escherichia coli K12 permeable to haemin.

Mutants of Escherichia coli which require 5-aminolaevulinic acid (5-ALA), the first intermediate of haem biosynthesis, do not respond to haemin and porphyrins. The probable explanation of the lack of response is that E. coli may be impermeable to haemin and porphyrins. Mutants are described which responded to haemin and porphyrins as well as to 5-ALA. Indirect evidence is presented that the mutants were permeable to haemin. The mutants showed other phenotypic changes, and resembled some mutants which are known to have changes in the cell envelope.

Aminolevulinic Acid↗