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Biomedical subjects

C Petitclerc

Publications and source records attributed to C Petitclerc.

At least 37 records · Page 2Linked to original sources

Familial articular chondrocalcinosis in Quebec.

The existence of articular chondrocalcinosis was documented in 9 members of 3 generations of a Quebec family. No associated or secondary forms of the disease were found. The clinical manifestations appeared early in life, and extensive radiologic involvement was apparent. We determined that genetic transmission was dominant, either autosomal or sex-linked, and not related to the HLA system.

Chondrocalcinosis↗

Automated quantification of bone and liver alkaline phosphatase isoenzymes of human serum.

Coupling two Technicon AAII samplers synchronised at 50 per hour with a 2 : 1 sample to wash ratio, sera are denatured and collected automatically. The incubation is done in continuous flow by passage through a U device made of large metallic needles soaked in a water bath at 60 +/- 0.1 degree C. This allows a very quick temperature equilibration and a very reproducible incubation time of 35 sec. Initial and residual activities of alkaline phosphatase (ALP: EC 3.1.3.1) are measured on a Rotochem II (Aminco) with the procedure recommended by the Société Française de Biologie Clinique (SFBC). For a mixture of bone and liver ALP, the initial rate constant of heat denaturation Kapp = (A X Kb) + (B X Kl), where A and B are the fractions of each isoenzyme in the mixture, and Kb and Kl the rate constants for bone (b) and liver (l) experimentally determined as 1.8 min-1 and 0.45 min-1 respectively. An equation was derived which converts the percent residual activity to a percentage of bone and liver isoenzyme: % bone ALP = 183--2.38 X % residual activity. This automated method was applied to 2700 people of both sexes from 4 to 100 years old.

Adolescent↗

Enzymatic activity patterns in probability population samples. Serum lactate dehydrogenase.

Sex- and age-specific serum lactate dehydrogenase values provided by a natural population of 2,378 individuals selected by a multistage area cluster probability sampling scheme are given. The activity of this enzyme has definite sex and age associations over the age range studied (larger than or equal to 10 years). In both sexes, it is characterized by elevations in preadolescents, by a sharp decrease in adolescent groups, and by a gradual increase in adult and senescent groups, which, however, does not bring it back to earlier levels. Males have higher mean serum lactate dehydrogenase activities than females in most age groups until about 50 years of age. Unusually high activities have been found in this study, compared with those found in two other widely separated areas in North America using the same assay procedures.

Adolescent↗

Serum urate levels between ages 10 and 14: changes in sex trends.

Urate levels were assayed in sera of 292 subjects between 10 and 14 years of age identified through a probability sample of a natural population. The sex trends in serum urate concentrations characteristic of childhood were seen to continue into early adolescence, with girls maintaining slightly higher means. Between 10 and 14 years there was first an overlap of male and female values followed by a reversal of trends, with much higher means in boys. Serum urate concentrations peaked in girls at age 11 and gradually stabilized at lower levels. Boys, on the other hand, showed little age variation in serum urate at 10 and 11 years but by age 12 showed sharp upward trends which continued throughout adolescence. Since age and body weight are known to be important covariates of serum urate, boys were matched to girls of the same age and body weight. Significant sex differences in urate levels persisted (after matching) only for 14-year-old adolescents and thus at this age could not be ascribed to weight differentials. The study highlights a peripubertal phenomenon whose mechanism might be endocrine related.

Adolescent↗

Population serum urate levels and their correlates. The Sherbrooke regional study.

A natural population has been studied for its serum urate levels and for host factors associated with these levels. Householdhood, ethnicity, drug and alcohol use were found to be negligible behavioral attributes with respect to population serum urate concentrations. Of interest among significant correlates of serum urate are smoking behavior, serum protein, creatinine, calcium and monocyte count. Predominant statistically significant host factors, however, are sex, body weight and age, body weight being linearly related in both sexes and age in females only.

Adult↗