PubMed Health⌕ Search

Biomedical subjects

C Lapointe

Publications and source records attributed to C Lapointe.

At least 19 recordsLinked to original sources
PubMed2004

Elastic torque and the levitation of metal wires by a nematic liquid crystal.

Anisotropic particles suspended in a nematic liquid crystal disturb the alignment of the liquid crystal molecules and experience small forces that depend on the particles' orientation. We have measured these forces using magnetic nanowires. The torque on a wire and its orientation-dependent repulsion from a flat surface are quantitatively consistent with theoretical predictions based on the elastic properties of the liquid crystal. These forces can also be used to manipulate submicrometer-scale particles. We show that controlled spatial variations in the liquid crystal's alignment convert the torque on a wire to a translational force that levitates the wire to a specified height.

Journal Article↗
PubMed2001

Home care of malaria-infected children of less than 5 years of age in a rural area of the Republic of Guinea.

OBJECTIVES: To assess the ability of mothers in a rural area of the Republic of Guinea to identify fever in their children, and to estimate the proportion of children who received antimalarial drugs. METHODS: Children under 5 years of age in 41 villages were selected by a two-step cluster sampling technique. During home visits we examined the children and questioned their mothers about the child's symptoms and treatment. FINDINGS: Of 784 children examined, 23% were febrile and more than half of them also had a positive smear result for Plasmodium. Mothers reported 63% of children with a temperature > or = 37.5 degrees C as sick. Among all children reported as feverish by their mother, 55% had a normal temperature (< 37.5 degrees C). In contrast, a temperature > or = 37.5 degrees C was found in 38% of children identified as sick but afebrile by their mother and in 13% of children considered healthy. Among febrile children, 18% were given chloroquine at home or had consulted at the health centre or a dispensary. CONCLUSION: In areas where malaria is endemic, recognition of fever and its presumptive treatment with antimalarial drugs is an essential part of the strategy of the World Health Organization (WHO) to reduce the morbidity due to this disease. This population study shows that mothers often failed to identify fever in their children and to consult or to provide antimalarial treatment. Without great efforts to improve home care, it is unlikely that the morbidity and mortality due to malaria in young children will be greatly reduced.

Antimalarials↗
PubMed2000

Who needs individual bioequivalence studies for narrow therapeutic index drugs? A case for warfarin.

Warfarin is, among drugs, considered to have a narrow therapeutic index for which individual bioequivalence has been suggested. To establish the propriety of "switching," an individual bioequivalence study involving a replicate-design study and three "switchings" in healthy subjects was undertaken using the U.S.-brand warfarin sodium tablet and a generic product. A randomized, single-center, open-label, single-dose, four-way crossover replicate bioequivalence study was performed in 24 healthy male volunteers in which each subject received the same 5 mg warfarin test and reference tablets twice on different occasions under fasting conditions. Concentrations of warfarin in plasma were measured by a validated specific HPLC method. The individual pharmacokinetic parameters obtained with test and reference products were compared using pooled data and Liu's method. Bioequivalence was shown with both average and individual bioequivalence methods. The individual bioequivalence assessment did not show a subject-by-formulation interaction, nor did it add value to the bioequivalence assessment of warfarin.

Adolescent↗
PubMed1997

High blood cadmium levels are not associated with consumption of traditional food among the Inuit of Nunavik.

High levels of cadmium in the liver and kidneys of caribous and sea mammals of the Canadian Arctic have led to recommendations to remove such offal from the traditional diet. Blood cadmium levels have been found to be very high in samples of Inuit volunteers, hence the hypothesis that the Inuit might be exposed to cadmium through their diet. This survey of a population-based random sample of Nunavik residents (n = 518) confirms that blood cadmium of Inuit is indeed very high by comparison to published reports. Blood cadmium levels are closely associated with the current smoking status and are independent of dietary patterns among nonsmokers. Plasma omega-3 fatty acids concentrations have been used to assess the reliability of the dietary information collected by questionnaires and to test for any association of blood cadmium with the consumption of sea mammals. Blood cadmium levels are not related to the reported consumption of sea mammals. Blood cadmium levels are very high among smokers and are associated with levels of exposure to tobacco. Among nonsmoking Inuit, blood cadmium levels are comparable with those reported in nonsmokers elsewhere in the world. In reference to international standards, blood cadmium concentrations are high enough among the Inuit to warrant energetic public health interventions.

Adolescent↗
PubMed1996

Sequential analysis of early hematopoietic reconstitution following allogeneic bone marrow transplantation with fluorescence in situ hybridization (FISH).

Using in situ hybridization with an X and Y chromosome probe mixture, we have sequentially studied peripheral blood samples from 10 patients (four males/six females) in an HLA-matched allogeneic setting in order to monitor the kinetics of early hematopoietic reconstitution. Interphase cells from smears consisting of purified granulocytic and lymphocytic populations respectively were studied in three patients at 24, 48, 72 and 96 h post-transplant. This period was arbitrarily defined as the immediate post-transplant period. These three patients plus seven others were studied sequentially at days 5, 10, 15, 20, 25 and 50 post-transplant, defined as the intermediate post-transplant period. The X and Y probes were indirectly labelled with rhodamine and fluoresceine isothiocyanate, respectively. Donor neutrophils were detected as early as 24 h post marrow infusion followed by a significant expansion at 48 h. At 96 h post-transplant, the median percentage of donor neutrophils was > 90%. In the immediate post-transplant period, most of the lymphocytes were of recipient origin. However, we have documented a significant expansion in donor lymphocytes, starting at day 5 post-transplant in most patients. Almost complete chimerism for the myeloid and lymphoid lineages was established at days 10 and 25 post-transplant, respectively. All patients engrafted normally according to standard clinical criteria. Follow-up data for those surviving > or = 100 days (eight patients), showed persistence of this pattern of hematopoietic reconstitution in all but one patient. Molecular monitoring of early engraftment has enabled us to unravel a distinct biphasic pattern of myeloid and lymphoid engraftment.

Bone Marrow Transplantation↗
PubMed1990

Variability in the ingestion of toothpaste by preschool children.

The amount of dentifrice used and ingested on three occasions by a group of 48 children aged between 3 and 5 years was measured. The purpose of the present study was to investigate the variability in the amount of dentifrice used and ingested. The quantity of toothpaste ingested was derived from the differences between the amounts used and rejected. On average, the difference in the amount used between any two brushings was less than 0.250 g for 66% of the subjects, and the difference in the amount ingested was less than 0.100 g for 69% of the children. There were no statistically significant differences in the quantities used and ingested between the three brushings.

Analysis of Variance↗
PubMed1989

[Eating disorders in a population of students of a college environment: correlation with 2 psychosocial characteristics].

The aims of this study were to measure the extent of severe eating disorders among female college students, to verify if there is a correlation with two indicators of "pressure to perform" while evaluating a screening instrument. Of 1144 female students, 16.3% scored 20 or above on the EAT-26 scale. Interviews allowed to determine that the positive predictive value of the EAT-26 when coupled with a low self-reported weight is considerably heightened. It was possible to estimate that over the last three years one girl out of 12 has presented severe eating disorders and one in 65 has suffered from anorexia nervosa. The EAT score was significantly correlated with the mother's level of schooling but not with the student's academic discipline.

Achievement↗
PubMed1988

[Relation between blood pressure and smoking in a population of Quebec workers].

Relations between blood pressure and cigarette smoking were investigated on the basis of a health survey conducted in a population of 3034 mine workers from Quebec Province. Blood pressure was found to be lower among smokers than among non-smokers, the difference between these two groups being: systolic pressure 2.3 mmHg, diastolic pressure 3.0 mmHg. After adjustment for age and bodyweight this relation persisted but only as far as diastolic pressure was concerned. The prevalence of hypertension was 1.5 times higher in non-smokers than in smokers. On the other hand, the number of cigarette-smoking years and the number of cigarettes smoked per day seemed to have little effect on mean arterial pressure.

Adult↗