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Biomedical subjects

M Ledoux

Publications and source records attributed to M Ledoux.

At least 19 recordsLinked to original sources
PubMed1992

Obesity and its relation to cardiovascular disease risk factors in Canadian adults. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To describe the distribution of weight and abdominal obesity among Canadian adults and to determine the association of obesity with other risk factors for cardiovascular disease. DESIGN: Population-based cross-sectional surveys. Survey nurses administered a standard questionnaire and recorded two blood pressure measurements during a home visit. At a subsequent visit to a survey clinic two further blood pressure readings were made, anthropometric measurements recorded and a blood specimen taken for plasma lipid determination. SETTING: Nine Canadian provinces, from 1986 to 1990. PARTICIPANTS: A probability sample of 26,293 men and women aged 18 to 74 years was selected from the health insurance registration files of each province. Anthropometry was performed on 17,858 subjects. OUTCOME MEASURES: Body mass index (BMI), ratio of waist to hip circumference (WHR), mean plasma lipid levels, prevalence of high blood pressure (diastolic greater than or equal to 90 mm Hg or patient on treatment) and self-reported diabetes mellitus. MAIN RESULTS: The prevalence of obesity (BMI greater than or equal to 27) increased with age and was greater in men (35%) than in women (27%). Abdominal obesity was likewise higher in men and increased with both age and BMI. The prevalence of high blood pressure was greater in those with higher BMI, especially in those with a high WHR. Although total plasma cholesterol levels increased only modestly with BMI, levels of low density lipoprotein (LDL) cholesterol and triglycerides and the ratio of total cholesterol to high density lipoprotein (HDL) cholesterol increased steadily, while HDL-cholesterol decreased consistently with increasing BMI. High total cholesterol levels (greater than or equal to 5.2 mmol/L) were more prevalent among people with high BMI, especially those with a high WHR. The prevalence of diabetes increased with BMI among those 35 years or older, especially those with abdominal obesity. About half of men and two-thirds of women who were obese were trying to lose weight. CONCLUSION: Obesity remains common among Canadian adults. There is a need for broad-based programs that facilitate healthy eating and activity patterns for all age groups. Health professionals should incorporate measurement of BMI and WHR into their routine examinations of patients to enhance their evaluation of health risk.

Adult↗
PubMed1992

Epidemiological evidence of an interaction between calcium and sodium intake impacting on blood pressure. A Montréal study.

Nutritional calcium and sodium are considered to be important regulators of blood pressure. This study was performed on 182 randomly selected Canadians from Montréal to test the relative contribution of these ions to systolic and diastolic blood pressure, as well as their interaction with other demographic indices. Multiple analysis of the total study population revealed that 28% (P less than .001) of systolic blood pressure was predicted by gender sodium, and calcium interaction (P = .003), weight, and the additive effect of age and weight. The same characteristics contributed to 37% (P less than .001) of diastolic blood pressure with an additional contribution of alcohol intake. Analysis by terciles of sodium and calcium intake indicated that the positive effect of sodium on blood pressure occurred only in subjects given a low calcium diet, whereas blood pressure was lowest in the tercile of both high calcium and sodium intake. The impact of the sodium and calcium interaction on blood pressure represented as much as a 10 mm Hg decrement of systolic blood pressure with 400 mg calcium/1000 kcal intake at the highest level of sodium consumption and a 6 mm Hg decrease for diastolic blood pressure. In subjects without a family history of hypertension, the same indices contributed up to 53% of systolic and 55% of diastolic blood pressure with a synergetic effect of sodium and calcium, indicating that blood pressure was lowest in subjects given a high calcium and sodium diet. For subjects with a family history of hypertension, there was no significant impact of sodium, whereas calcium intake contributed negatively to both systolic and diastolic blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Chronic treatment with pentazocine or SFK 10047 decrease proenkephalin mRNA levels in the rat striatum and nucleus accumbens.

In order to assess the effect of sigma (sigma) receptor activity on striatal and limbic enkephalinergic cells we measured proenkephalin mRNA levels by in situ hybridization histochemistry after chronic treatment with the sigma-receptor agonist drugs SKF 10047 or pentazocine. Chronic treatment with SKF 10047 decreased proenkephalin mRNA levels in the anterior aspect of the caudate-putamen (CPU) and the nucleus accumbens by 20-22% relative to controls. No significant effect was observed in the medial aspect of the CPU. Treatment with pentazocine decreased proenkephalin mRNA levels by 20-25% in all 3 brain regions. The results demonstrate that sigma-receptor activity can exert tonic effects on proenkephalin mRNA expression in the striatum and the nucleus accumbens of the rat.

Animals↗
PubMed1991

Isolation stress increases tyrosine hydroxylase mRNA in the locus coeruleus and midbrain and decreases proenkephalin mRNA in the striatum and nucleus accumbens.

Isolation of adult animals represents a form of psychological stress from which the animals cannot escape. In order to assess the effect of this stressor on neurochemical substrates in the brain, we assessed behavior and measured tyrosine hydroxylase and proenkephalin mRNA levels in selected brain areas by in situ hybridization histochemistry. Tyrosine hydroxylase (TH) mRNA levels in the locus coeruleus (LC) were significantly and progressively increased by 18, 42 and 68% after 7, 14 or 28 days of isolation, respectively. TH mRNA in the midbrain was transiently increased by isolation. Levels were significantly elevated by 34 and 48% above group-housed controls in the ventral tegmentum and the substantia nigra, respectively, after 14 days of isolation. In the forebrain, proenkephalin (PE) mRNA levels were found to be transiently decreased by 29% in the anterior and medial aspects of the caudate-putamen and the nucleus accumbens after 7 or 14 days of isolation stress, but the levels returned toward control levels after 28 days of isolation. Behavioral tests indicate that isolated animals progressively became more aggressive with duration of stress and showed a small but significant decrease in locomotor activity. The results demonstrate that a physically noninvasive stressor such as isolation of adult male rats can produce significant alterations in brain neurochemistry. The neurochemical responses observed may represent a brain mechanism designed to help the organism adapt to or protect from the deleterious effects of chronic psychological stress.

Animals↗
PubMed1991

Regulation by dopaminergic neurotransmission of dopamine D2 mRNA and receptor levels in the striatum and nucleus accumbens of the rat.

The effect of dopamine depletion or pharmacological blockade of dopamine receptors on striatal and accumbens dopamine D2 mRNA and receptor levels was assessed by in situ hybridization histochemistry and receptor autoradiography. The time course of pharmacological blockade with haloperidol demonstrates a complex mode of regulation of dopamine D2 mRNA and receptor levels. By day 8 of haloperidol treatment, D2 mRNA and receptor levels were decreased (up to 20%) in the medial and anterior aspects of the caudate-putamen (mCPU and aCPU) and the nucleus accumbens (NAc). However, by day 21 of haloperidol treatment, D2 mRNA and receptor were increased relative to vehicle-injected controls. Likewise, unilateral dopamine depletion due to 6-hydroxydopamine (6-OHDA) lesions of mesencephalic dopaminergic neurons resulted in decreased levels of D2 receptor mRNA by day 8 post-lesion in the ipsilateral mCPU, aCPU and the NAc. However, at days 14 or 21 post-lesion, there was a reversal of the effect with increases of up to 22% in all brain regions ipsilateral to the lesion. Although no decreases in receptor level were observed at day 8, significant increases in receptor level in all three brain regions were detected at days 14 and 21 post-lesion. The results demonstrate that midbrain dopaminergic innervation exerts tonic effects on the levels of dopamine D2 receptor and mRNA in the caudate-putamen and the nucleus accumbens of the rat. Changes in receptor level are frequently accompanied by comparable changes in mRNA level, indicating a mass action relationship between receptor level and receptor biosynthesis in these forebrain regions in the rat.

Animals↗
PubMed1991

Genomic effects of cold and isolation stress on magnocellular vasopressin mRNA-containing cells in the hypothalamus of the rat.

We assessed the effects of cold and isolation stress on arginine vasopressin (AVP) mRNA in the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus. Vasopressin mRNA levels were determined by in situ hybridization histochemistry at the cellular level. In posterior magnocellular neurons of the PVN isolation stress for 7 or 14 days increased vasopressin mRNA levels 28 and 29%, respectively, compared to group-housed controls. No significant alterations in vasopressin gene expression were observed in the SON after 7 or 14 days of isolation stress. Scattered magnocellular AVP mRNA-expressing cells of the medial parvocellular PVN showed increases of 19 and 34% after 7 and 14 days of isolation, respectively. We also studied the effect of cold or combined cold and isolation stress on vasopressin gene expression in the PVN and SON. Cold stress for 3 h daily for 4 consecutive days increased AVP mRNA levels in the posterior magnocellular PVN by 15%. Cold-isolated animals showed an increase of 21%. No significant effect on AVP mRNA levels in the SON was observed. In contrast to the posterior magnocellular PVN, cold or cold-isolation stress increased AVP mRNA in magnocellular neurons of the medial parvocellular region of the PVN by 25 and 43%, respectively, relative to control rats. These results suggest that psychological and metabolic stress may be added to the list of stressors that activate the hypothalamo-neurohypophysial system.

Animals↗
PubMed1991

Interactions among calcium, sodium, and alcohol intake as determinants of blood pressure.

It has been reported that calcium intake may effectively modulate the expression of hypertension affected by sodium. The present study extends our previous analysis of this calcium-sodium interaction, additionally demonstrating that calcium, sodium, and alcohol intake further contribute to both systolic and diastolic blood pressures in normotensive subjects. Calcium intake was related to lower blood pressure over all ranges of sodium and alcohol intake, and alcohol intake contributed positively and significantly to both systolic and diastolic blood pressures. However, sodium was associated with increased blood pressure only at low calcium intake, particularly in subjects who consumed large amounts of alcohol. This study points to a significant interaction among sodium, calcium, and alcohol intake as determinants of blood pressure, which, together with gender and weight, contribute to 31% of systolic blood pressure and with the addition of age to 36% of the variance in diastolic blood pressure.

Adult↗
PubMed1991

[Recurrent erysipelas].

Erysipelas is clinically defined as a febrile skin infection with a sudden onset of a red indurated expanding plaque with distinct border. A typical erysipelas presents various degrees of cutaneous erythema, oedema and is characterized by less well-defined margins. The responsible agent can be a beta-hemolytic streptococcus (group A), Staphylococcus aureus and other streptococci (group B, C and D). Common predisposing factors are venous insufficiency, lymphatic obstruction and underlying illnesses. Guidelines for the diagnosis and the management of erysipelas are proposed. The episodes of erysipelas ordinarily respond promptly to penicillin or a beta-lactamase resistant antibiotic. Prevention of recurrent erysipelas by means of an antibiotic prophylaxis is discussed.

Anti-Bacterial Agents↗
PubMed1991

[Prevention and treatment of pressure ulcers].

Pressure is the primary pathogenic factor in the development of ulcers but other major factors are shearing forces, friction and moisture. Significant risk factors are immobility, nutritional status and age-related diseases. Complications of pressure ulcers can be life threatening. The authors wish to stress preventive measures and also recommend a therapeutic approach based on the grade of ulcer present. Prevention is best achieved by identification of high risk patients, alleviation of causative and predisposing factors and early detection of ischemic skin changes. The treatment includes local wound care that eliminates necrotic tissue, decreases bacterial load and provides a physiologic environment allowing the wound to heal, and systemic treatment: adequate nutrition, correction of underlying illnesses and systemic antibiotics (in case of sepsis, cellulitis, osteomyelitis or the prevention of bacterial endocarditis).

Aged↗
PubMed1991

[Immunohistology of bullous autoimmune skin diseases].

Autoimmune bullous dermatoses undertake frequently oropharyngeal mucous membranes and the skin surface, either in succession or simultaneously. Actual observation technics by photon and electron microscopy, by immunofluorescence and immunohistochemistry (with specific antibodies) have allowed to differentiate more particularly pemphigus, bullous pemphigoid, cicatricial pemphigoid, acquired bullous epidermolysis, all autoimmune bullous affections.

Autoimmune Diseases↗
PubMed1990

["Insect bite" and Borrelia].

A case of insect bite with a peculiar evolution is presented. The simultaneous inoculation of Borrelia burgdorferi and the treatment are discussed.

Borrelia burgdorferi Group↗
PubMed1989

Patterns of experimental contamination by Protogonyaulax tamarensis in some French commercial shellfish.

As a result of the proliferation of toxic marine dinoflagellates along European coasts and the recent discovery of paralytic poisons in French shellfish, experimental studies were conducted on four species of shellfish from the Brittany coasts. Contamination rates of a culture of toxic Protogonyaulax tamarensis, were determined for Mytilus edulis, Crassostrea gigas, Pecten maximus and Ruditapes philippinarum. Mussels and scallops were very rapidly contaminated showing high toxin accumulation rates, whereas rates for oysters and clams were low. During the decontamination phase, two stages were observed in mussels and scallops: a fast decrease in toxin, of the same order of magnitude as the accumulation, followed by a slow decrease, with the toxic rate remaining above the quarantine level of 80 micrograms/100 g. Toxin analysis, both in the culture and in the shellfish, was performed using high performance liquid chromatography. GTX3 and GTX8/epiGTX8 were the dominant toxins in the early stage of the decontamination phases, whereas GTX2 was the predominant compound during the slow phase of decontamination.

Animals↗
PubMed1989

Iron deficiency among active men.

Iron deficiency in active men is well documented. To assess the relative importance of dietary iron intake, iron absorption, and iron loss in the pathogenesis of this iron deficiency, we compared a group of iron-deficient athletes to a group with normal iron stores. Iron absorption was assessed by an iron tolerance test. Serum haptoglobin was used as a measure of hemolysis. The presence of hemoglobinuria reflected urinary iron loss. Iron intake was determined by a 3-day dietary record as well as a food frequency questionnaire. Results showed iron absorption to be inversely correlated with iron stores. Iron-deficient athletes had higher absorption, suggesting a normal regulation mechanism. Major hemolysis (serum haptoglobin below 40 mg/dl) was found in 28% of subjects with no relationship to iron stores. No hemoglobinuria was detected after a usual training session. Iron intake was elevated in relation to high caloric intake, but iron intake in the form of meat was lower in iron-deficient athletes, as compared to those with normal or repleted iron stores. It is our opinion that inadequate iron intake is an important determinant of iron deficiency in athletes.

Absorption↗
PubMed1989

Oculocerebral hypopigmentation syndrome (Cross syndrome) in a Gipsy child.

A boy aged 2 years, born prematurely to Gipsy parents, presented with hypopigmentation severe encephalopathy with athetoid movements, bilateral ocular anomalies including cloudy corneas, iris atrophy and cataracts, as well as dental defects. Ultrastructural examination of the skin disclosed scare melanosomes. Although the neurologic and ocular anomalies might have been accounted for by his extreme prematurity, their association with hypomelanogenesis and dental defects support, in this patient the diagnosis of the oculocerebral hypopigmentation syndrome (Cross syndrome).

Albinism↗
PubMed1989

[Lesions of the acetabular rim. Clinical manifestations, therapeutic strategies and perspectives].

Partial rupture of the acetabular rim have usually been described as accompanying traumatic or dysplasic dislocations of the hip. The five cases reported here are in favor of a specific pathology of this fibrocartilage as it is in the knee or the shoulder. Besides, the functional symptoms are not without reminding that of these two joints with sudden onset of cracks, jerks, blockings and even a real joint instability. The pain is never isolated, but may accompany other disorders. The cases were selected in order to evaluate the clinical manifestations and the therapeutic consequences of such a lesion according to the articular history. The diagnosis can only be confirmed with arthrography, which, in addition, permits to evaluate the size of the rim and the condition of the cartilage. The three patients who underwent surgery presented the lesions shown on arthrography. The problem lies in the possible arthrogenic potential of a tear, left in place because minimally disabling for the patient.

Acetabulum↗