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Biomedical subjects

C Prévost

Publications and source records attributed to C Prévost.

26 records · Page 2Linked to original sources
PubMed1990

[Motor and sensory neuropathies with or without agenesis of the corpus callosum: a radiological study of 64 cases].

In 1971, Andermann and Andermann described an autosomal recessive syndrome found within the Charlevoix and the Saguenay populations (Quebec, Canada) characterized by agenesis of the corpus callosum (ACC) associated with motor and sensory neuropathy, mental retardation and dysmorphic features. A study of CT in 64 patients demonstrated a total ACC in 37 cases (57.8%), partial ACC in 6 cases (9.4%) and the presence of the corpus callosum in 21 cases (32.8%). The latter was confirmed by MRI in 3 cases. CT of patients without ACC revealed a high frequency of developmental or degenerative midline anomalies, particularly interhemispheric fissure enlargement and posterior fossa atrophy. The clinical presentation and the natural course of the neuropathy, the intellectual impairment and the behavioural manifestations are identical amongst individuals with or without ACC. Individuals with or without ACC are found within the same family and often within the same sibship. These observations support the hypothesis of a single genetic syndrome in which the constant manifestation is the motor and sensory neuropathy.

Adolescent↗
PubMed1989

Myotonic dystrophy: linkage with apolipoprotein E and estimation of the gene carrier status with genetic markers.

The genes for myotonic dystrophy (MD) and for apolipoprotein E (ApoE) belong to a chromosome 19 synthenic group of markers. A familial linkage analysis between MD and ApoE was performed using the J Ott LIPED program (IBM PC/XT, April 1984) to estimate the genetic distance between these 2 genes. Of a total of 136 individuals in 11 MD families, 81 were confirmed to be affected by the disease and 41 were asymptomatic. ApoE phenotypes were determined in 115 of these 122 individuals. No recombinant was observed out of 74 meioses which were informatives for both MD and the ApoE isoproteins. A global maximal lod score Z of 19.00 was obtained at the recombination fraction theta = 0. The upper theta value at the confidence interval corresponding to the peak lod score (Z max) - 1 was 0.03. This suggests that the loci for MD and ApoE are at a distance of 0 to 0.03 Morgan. Since ApoE and apolipoprotein C2 (ApoC2) have been shown by others to be about 40 kb apart, our data are therefore consistent with the distance estimate of 0.02 Morgan reported between MD and ApoC2. The D19S19 (LDR152) polymorphic DNA sequence is also tightly linked to MD on chromosome 19. The segregation of ApoE isoproteins and of ApoC2 and D19S19 DNA polymorphism was utilized for evaluating the probability for individuals at risk of inheriting the disease gene in MD families. Data are presented on 3 families to emphasize the usefulness of genetic markers to estimate the MD gene carrier status of asymptomatic individuals and also for those presenting a partial syndrome. The limitations of such approach are also discussed.

Apolipoproteins E↗
PubMed1989

Tertatolol increases glomerular filtration and urinary sodium in anesthetized rats.

Tertatolol is a new beta-adrenergic blocking agent that possesses unique actions on kidney function. In the present study, the effect of increasing doses of tertatolol (0.025, 0.05, 0.1, 0.2 and 0.3 mg) was examined in different groups of anesthetized rats and the results compared with injection of the vehicle. Bolus i.v. injections of tertatolol resulted in a dose-related elevation of urine volume (UV), from 4.1 +/- 0.3 to 6.0 +/- 0.4, 10.2 +/- 1.3, 13.8 +/- 1.2, 18.8 +/- 1.9 and 16.4 +/- 1.8 microliters/min, respectively. Similarly, urine Na increased from 0.4 +/- 0.1 to 0.8 +/- 0.2, 1.2 +/- 0.2, 2.2 +/- 0.3, 3.4 +/- 0.7 and 2.9 +/- 0.6 mueq/min. These changes were associated with a progressive rise in glomerular filtration rate (GFR) from a mean control value of 1.15 +/- 0.10 to 1.28 +/- 0.09, 1.41 +/- 0.07, 1.50 +/- 0.10, 1.62 +/- 0.16 and 1.48 +/- 0.07 ml/min. No change in urinary phosphate excretion was observed. In a separate group of studies, the effect of tertatolol was compared with propranolol (1 mg): the maximal elevation on UV and urine Na was less than 25% of that obtained with tertatolol. Elevation of GFR was also 30% higher in animals receiving tertatolol. The effect of tertatolol on UV and urine Na resulted in part from the rise in GFR but also from tubular inhibition of Na transport, since fractional Na excretion increased from 0.24 +/- 0.09 to a maximal value of 1.76 +/- 0.10%. This tubular action presumably occurs beyond the proximal nephron, because no effect on urinary phosphate excretion was obtained during tertatolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1987

Diuretic and natriuretic properties of prestegane B, a mammalian lignan.

The effect of increasing doses of prestegane B, a synthetic lignan, was examined in the anesthetized normal rat, using clearance methodology. Increasing doses of prestegane B 0.5, 1.0, 2.0, and 5.0 mg) were administered intravenously in our separate groups of hydropenic rats. Urine flow increased by 2.8 +/- 0.3, 4.5 +/- 0.5, 7.7 +/- 0.5, and 18.2 +/- 0.8 microliters/min, respectively, above control values. The rise of urinary sodium secretion was of similar magnitude and averaged 0.4 +/- 0.1, 0.8 +/- 0.2, 1.1 +/- 0.3, and 2.4 +/- 0.3 mu eq/min, respectively. No significant change in urinary phosphate excretion was obtained in all groups of rats, and glomerular filtration rate remained constant from control to experimental clearance periods. The natriuretic effect of prestegane B observed in this in vivo model could be related to the inhibition of the Na+-K+-adenosine triphosphate activity demonstrated in vitro in previous studies from our laboratory. The action of this substance is likely to be situated beyond the proximal tubule, since urinary phosphate was not altered. Prestegane B mimics the effects of other endogenous diuretic and natriuretic hormones, but its site of action and its effect on renal hemodynamics are obviously different.

4-Butyrolactone↗
PubMed1985

[Endoscopy for exploration for foreign bodies of the lower respiratory tract of the child. Apropos of 668 cases].

From 1980 to 1984, 335 foreign bodies (FB) were extracted from lower respiratory tract of children: two-thirds were boys, 77% were under 3 years of age, 79% presented signs of penetration. The FB was mainly of alimentary origin, particularly peanuts. Radiologic imaging provided inconstant signs, atelectasis increasing in frequency with duration after inhalation. Laryngeal and tracheal FB were rare (15 and 19 cases respectively), and the site of impaction was divided equally between the left and right bronchi. Multiple, sometimes bilateral FB are frequent and FB of a vegetable nature are of serious omen. During the same period, 283 endoscopies for suspected FB gave negative results, and FB was found in 6 of 50 cases undergoing endoscopy for repeated pulmonary infections. In this latter group the percentage of boys was lower and the age of the children a little higher than in the group with a detected FB. These findings suggest the need for endoscopy under general anesthesia and the use of a rigid tube in all suspected cases of FB in the lower respiratory tract.

Adolescent↗
PubMed1980

Regluating factors in helper T-cell maturation.

The effect of soluble and insoluble thymic fractions (STF and ITF, respectively) on the antibody response to sheep red blood cells (SRBC) was tested at different times after injection in mice. In normal mice, a temporary increase in the number of plaque forming cells (PFCs) was observed after injecting either ITF and STF, this increase being more prolonged when both fractions were injected together. In thymectomized, lethally irradiated mice repopulated with syngeneic untreated bone marrow, full reconstitution of T helper function was achieved only if both ITF and SFT were injected, partial reconstitution being obtained when either of these fractions was administered alone. In thymectomized, lethally irradiated mice repopulated with T-depleted bone marrow, reconstitution of the T helper function was only achieved when both ITF and SFT were administered. These results show that ITF and STF together constitute all the essential elements of the thymic microenvironment necessary to support the entire differentiation process of prethymic precurosors into helper T cells.

Animals↗
PubMedDate not supplied

Suicides associated with the Jacques Cartier Bridge, Montreal, Quebec 1988-1993: descriptive analysis and intervention proposal.

Falls from heights represent an uncommon means of suicide. Regional variations are attributable to the presence of particular sites which attract suicidal individuals. The Jacques Cartier Bridge in Montreal is one such site, though less well known than North American sites such as the Golden Gate Bridge or Niagara Falls. According to Coroner's records, 54 suicides were associated with the bridge for the period 1988 to 1993. All but one of the suicides were the result of jumps from the bridge. The median age of victims was 30 years, and 46 of the victims were male. Bridge-specific verbalization of suicidal intent and prior history of medically diagnosed psychiatric disorders are frequently noted. Based on a review of the effectiveness of preventive measures, we propose limiting access to jumping by means of a fence along the bridge railing.

Adolescent↗