PubMed Health⌕ Search

Biomedical subjects

F Chevalier

Publications and source records attributed to F Chevalier.

24 records · Page 2Linked to original sources
PubMed1982

Glucose-stimulated insulin secretion in rats with normal plasma calcium levels: effects of calcium deficiency.

Weanling Wistar rats were pair-fed for 9 days a control or a calcium-deficient diet. After a 12-hour fast the rats were injected intraperitoneally with glucose (250 mg/100 g body weight), and blood was collected 15, 30 and 60 minutes after the injection. Before injection, calcium (9.7 +/- 0.2 mg/100 ml), glucose and insulin plasma levels were identical in the control and deficient animals, although calcium-deficient animals showed a small but significant increase in blood plasma magnesium levels. Blood glucose levels were higher in the calcium-deficient rats than in control rats 15 to 30 minutes after the glucose injection (15.4 +/- 1.4 vs. 9.7 +/- 0.4 mM, P less than 0.01, 30 minutes after). Plasma insulin levels were significantly lower 15 minutes after the glucose injection (24 +/- 4 vs. 73 +/- 8 microU/ml; P less than 0.01). Calcium deficiency is therefore associated with a decreased response to the glucose tolerance test in the absence of any change in the blood plasma calcium levels.

Animals↗
PubMed1982

Ultrasonic echography in the mare.

Ultrasonic echography in the mare allows pregnancy diagnosis as early as Day 14 after ovulation. In the 1980 and 1981 breeding seasons, a total of 7438 examinations of 4688 mares were performed on several farms with the same apparatus. The accuracy of positive pregnancy diagnosis was estimated to be greater than 95% and of non-pregnancy diagnosis greater than 84%. When abnormal pictures of vesicles are found, it has to be decided whether it is a conceptus or a cystic structure. Most small vesicles do not develop, whereas large ones, deformed shapes, presence of some echoes, or a division inside the vesicle most often represent a growing conceptus or sometimes twins. Twinning rate in early pregnancy (before Day 30) lies between 2.6 and 2.8%. Twins are suspected when there are 2 vesicles of equal size (observed successively rather than simultaneously) (50-60% are confirmed), unequal size (less than 9%) or one oversized vesicle (23%), one of an irregular shape (5%) or a divided vesicle (33%). No effect of the month of mating on the rate of twin conceptions was found. Early pregnancy loss (between mean Days 23 and 43) was estimated at 5.3% and total embryonic loss (early and late) at 9%. Rate of embryonic death increased in proportion to the interval between the two successive diagnoses. No critical period of early mortality or effect of the reproductive status on embryonic or fetal mortality was found.

Animals↗
PubMed1978

Evidence for independent genetic regulation of the expression of different antibody classes in anti-sheep red blood cell responses.

Three levels of variation are described in the response to sheep red blood cells (SRBC). Inbred strains of mice are distinguishable in terms of early or late kinetics of IgM response, high or low overall IgG response, and the relative expression of IgG1, IgG2a and IgG2b antibody in their response to SRBC. Results using C57BL/10 hybrid progeny strongly suggest a genetic control of these different aspects of the anti-SRBC response. The IgM kinetic pattern and the quantitative IgG response are regulated by two independent multigenic systems. Evidence is also presented for a distinction between the genes controlling the quantitative IgG response and those which control the 7 S isotypic pattern. IgG2a antibody expression seems regulated by a single gene. Neither group of genes involved in these various types of regulation seems directly linked to the H-2 complex or to the CH allotype. The hypothesis that 4 different sets of genes might control IgM, IgG1, IgG2a and IgG2b expression is discussed.

Animals↗