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R Labarre

Publications and source records attributed to R Labarre.

4 recordsLinked to original sources
PubMed1994

Testing for inter-group contamination in a controlled longitudinal study of added physical education.

OBJECTIVE: This case report examines whether there was any cross-contamination between students enrolled in classes that received additional physical education, and their siblings who were enrolled in preceding and succeeding class-cohorts. EXPERIMENTAL DESIGN: A controlled longitudinal study extending over 6 years of primary school. SETTING: An urban and a rural primary school in Québec. PARTICIPANTS: 546 primary students, comprising approximately equal numbers of boys and girls from the urban and the rural school. INTERVENTION: Entire class-cohorts were given and hour of additional physical education ach day throughout their primary schooling, with immediately preceding and succeeding class-cohorts serving as controls. MEASURES: The measured data included standing height, body mass, maximal oxygen intake (direct treadmill test) and PWC170. RESULTS: We found no evidence of cross-contamination between siblings in experimental and control class-cohorts. CONCLUSION: Although a theoretical possibility, cross-contamination between students in preceding and succeeding class-cohorts does not seem an important source of error in primary school students, presumably because such children prefer to play with friends from their immediate age cohort.

Bias↗
PubMed1983

Alternative forms of lethality in mitomycin C-induced bacteria carrying ColE1 plasmids.

We have studied the physiological effects of mitomycin C induction on cells carrying ColE1 plasmids with differing configurations of three genes: the structural gene coding for colicin (cea), a gene responsible for mitomycin C lethality (kil) that we located as part of an operon with cea, and the immunity (imm) gene, which lies near cea but is not in the same operon. kil is close to or overlaps imm. When cea(+) plasmids are present mitomycin C induction results in 100-fold or greater increases in the level of colicin. Within an hour after induction more than 90% of cells carrying cea(+)kil(+) plasmids are killed and macromolecular synthesis stops, capacity for transport of proline, thiomethyl beta-D-galactoside, and alpha-methyl glucoside is lost, and the membrane becomes abnormally permeable as indicated by an increased accessibility of intracellular beta-galactosidase to the substrate o-nitrophenyl beta-D-galactoside. All of these events occur when a cea(-)kil(+)imm(+) plasmid is present and none does when the plasmid is cea(+)kil(-)imm(+), so the damage can be attributed solely to the Kil function and not to the presence of colicin. However, cells carrying a cea(+)kil(-)imm(-) plasmid are killed upon induction, apparently by action of endogenous colicin on the nonimmune cytoplasmic membrane. The pattern of accompanying physiological damage is distinguished from the kil(+)-associated damage by an enhancement of alpha-methyl glucoside uptake and accumulation and efflux of alpha-methyl glucoside 6-phosphate and by an absence of the alteration in membrane permeability for o-nitrophenyl beta-D-galactoside. These features are typical of colicin E1 action on the membrane. The induced damage is not prevented by trypsin and occurs in cells of a strain specifically tolerant to exogenous colicin E1, indicating that the attack is from inside the cell.

Antibiotics, Antineoplastic↗
PubMed1979

[Bone maturity and physical performance].

We have examined the relation between physical performance (as measured with the CAHPER tests), bone age (Greulich and Pyl's wrist evaluation) and dental age (Garn's method). Our study included 164 boys and 149 girls aged from 7 to 11. In spite of interesting significant simple correlation between most of the CAHPER tests and bone age measurements for the pre-pubescent period, the latter remains of negligible value in predicting physical performance in the studied children when variables like chronological age, body height and body weight are already included in the prediction equation.

Age Determination by Skeleton↗