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Biomedical subjects

R Landry

Publications and source records attributed to R Landry.

10 recordsLinked to original sources
PubMed1998

Groundwater contamination by nitrates associated with intensive potato culture in Québec.

In rural areas, groundwater contamination by nitrates is a problem related to the spreading of organic and chemical fertilizers by farmers and, to some extent, to effluents from domestic sewage systems. Health effects of groundwater contamination by nitrates have been assessed several times and may lead to important consequences for infants. Following pressures from citizens in 1990, a survey of well water quality around potato fields of the Portneuf county (Québec) found that nitrate contamination was frequently above the 10 mg-N/1 standard. Because this first survey was limited to areas of intensive potato culture, it was not possible to evaluate the real impact on the groundwater quality for the whole county and the subsequent public health intervention was spread over the entire region. A second survey was carried out in 1995 to reevaluate the situation using random sampling methods. This latter study took into account drinking water habits of the population, the relative importance of potato culture as a source of nitrogen loading, the effects of soil types, and waste-water disposal systems as well as land use on nitrate concentration in private well water. The data analysis was carried out by combining GIS and statistical methods to test hypotheses about the spatial relationship linking measured nitrate concentrations with their immediate environment. This paper presents the major findings from this second study which confirm the impact of intensive potato culture on groundwater nitrate concentrations, mainly localized in sandy soil areas within 2 km of fields. Finally, it illustrates the usefulness of GIS to focus public health interventions.

Agriculture↗
PubMed1991

The prevalence of the retrocuspid papilla among three indigenous groups of patients. Study of the subjects in Ecuador, Honduras and Nicaragua.

The retrocuspid papilla (RCP) is a soft well circumscribed nodule located lingually to the mandibular cuspid on the gingival tissue surface. The RCP is observed more frequently in young children and regresses or disappears with age. Little information is available in the literature on this structure. The prevalence of the RCP is discussed as it relates to its distribution among three groups of Latin American patients: those of southern Ecuador, northeastern Honduras and eastern Nicaragua. The distribution by age, sex, symmetry and gingival position is evaluated. Based on the analysis of the results, it was determined that: the RCP is most prevalent in under-five age group at a relative frequency of 25 per cent; its prevalence decreases progressively with age; it is present significantly more often among females in the Honduras group; a unilateral distribution is more frequent than a bilateral distribution, except for the Nicaragua group, where a bilateral distribution prevails; and it is most frequently located on the attached gingiva as compared to free gingiva and mucosa. The clinical significance of the RCP resides in the fact that it may simulate pathological gingival conditions from which it must be differentiated.

Adolescent↗
PubMed1985

Comparison of isometric exercise and high volt galvanic stimulation on quadriceps femoris muscle strength.

The purpose of this study was to compare the effectiveness of both high volt galvanic current (HVG) and isometric exercise to strengthen the quadriceps femoris muscles in 17 healthy subjects. The subjects were divided into three groups. The Control Group (n = 6) received no exercise or stimulation. The Isometric Exercise Group (n = 5) performed 15 sessions of maximum isometric contractions, and the Electrical Stimulation Group (n = 6) engaged in 15 sessions of electrically stimulated isometric contractions. The Isometric Exercise Group was found to have an increase in strength significantly greater (p less than .05) than either the Control or Electrical Stimulation Group. No increase in strength was observed in either the Control or Electrical Stimulation Group. This study indicates that HVG stimulation is not as effective as isometric exercise in increasing strength in muscle.

Adult↗
PubMed1984

Venous pressure in man during weightlessness.

To determine whether the body fluid shift from the lower limbs toward the head that occurs during spaceflight leads to lasting increases of venous pressure in the upper body, venous pressure and hematocrit measurements were made on four astronauts before flight and 1 and 12 hours after recovery and compared with measurements in space. During the mission the hematocrit was elevated and the venous pressure lowered by 1 to 8 centimeters of water as compared with the preflight data. One hour after landing the hematocrit decreased, indicating a hemodilution, venous pressures were unexpectedly high, and a body weight loss of 4 to 5 percent was observed. Twelve hours later the venous pressures were the lowest recorded during the study. The fluid shift apparently takes place during the first several hours of spaceflight. Thereafter, the pressure in the peripheral veins and the central circulation is lower than that measured before flight.

Body Fluids↗
PubMed1979

Effect of a group perceptual-motor training program on kindergarten children.

For 21 boys and 24 girls in a middle-class kindergarten no differences in Identification of Body Parts, Copy Forms, or Motor Skills Test of the Rosner-Richman Perceptual Survey were noted. Scores increased from September to May testing on copying and motor skills, e.g., walking a rail, balancing, handling balls, as expected.

Child Development↗