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Biomedical subjects

A Simon

Publications and source records attributed to A Simon.

At least 199 records · Page 11Linked to original sources
PubMed1997

Comparison of cardiovascular risk profile between male employees of two automotives companies in France and Sweden. The Coeur Project Group.

To determine whether or not the lower rate of coronary disease in France, in comparison with Sweden, might be explained by different cardiovascular risk profiles, a cross-sectional analysis (first step of a longitudinal study) of comparable samples of automotive workers was carried out in corporate occupational health clinics of Renault and Volvo. Traditional cardiovascular risk factors were evaluated and the Framingham coronary risk was estimated for 1000 randomly selected 45-50 years old Caucasian males from each company. Compared with the Frenchmen, the Swedish men consisted of more white collar workers and were slightly older. After adjustment for age and blue/white collar status, the Swedish men showed lower body mass indexes, waist to hip rations and heart rates, lower frequency of treatment of hypercholesterolemia and diabetes than the Frenchmen. The Swedish males also exhibited higher averages of blood cholesterol, low density lipoprotein (LDL) cholesterol and glucose, but lower frequencies of hypercholestrolemia and diabetes, and a higher frequency of family histories of cardiovascular disease. Blood pressure, hypertension prevalence, triglycerides level, and high density lipoprotein (HDL) did not differ between the groups. The average number of traditional risk factors was 1.1/person for the Frenchmen and 0.8/person for the Swedes. However, the coronary risk as estimated using the Framingham index was not different between the groups. This, together with the more frequent family history of cardiovascular disease in Swedish men, suggests a lower susceptibility to risk factors as a possible explanation for the lower cardiovascular disease prevalence reported in France, and/or the possibility that factors not measured were involved.

Age Factors↗
PubMed1997

[Glycerol supplementation in broiler rations with low crude protein content].

In connection with the utilization of glycerol, which could become available as a by-product of the fuel production from rapeseed the influence of glycerol feeding with rations of low crude protein content was proved. 61 male day old broiler chickens received ad libitum 8 experimental rations based on maize and soybean meal. The experimental design included 3 factors: 15 or 18% CP; supplementation of essential amino acids or not and a content of pure glycerol of 0 or 10%. During the experimental feeding of 23 days body weight gain, feed conversion ratio, N-balance and the intake and excretion of glycerol was obtained. At the end of the trial the utilization of 15N-methionine and the glycerol content of blood plasma, liver and breast muscle was estimated. Due to the low crude protein content of the rations the body weight gain and N-balance was very low (BWG day 1 to 23: 8.6 to 17 g/animal.d; N-balance day 19 to 23: 0.4 to 1.0 g N/animal.d). The supplementation of essential amino acids was the factor with the highest improving effect on the body weight gain, feed conversion ratio and N-balance. Especially at the begin of the trial animals which received 10% glycerol had have an increased feed intake. The excretion of the supplemented glycerol by excreta amounted to 26% of the intake. However, the glycerol content of the rations did not effect body weight gain, feed conversion ratio, N-balance or utilization of 15N-methionine significantly. The assumption of a saving effect on glucoplastic amino acids due to glycerol feeding could not be manifested. In the mean feeding of glycerol elevated the glycerol level in blood plasma in comparison to the basal level up to 23 times (from 0.6 to 13.6 mumol/ml) and in the breast muscle up to 19 times (from 0.4 to 7.5 mumol/g). Nevertheless, these values were lower than the basal level of glycerol in the liver (17.1 to 19.0 mumol/g), which was significantly increased by glycerol feeding to 128%. Regarding the utilization of glycerol as a by-product of the production of renewable fuels it can be concluded that on the basis of the estimated parameters 10% pure glycerol in broiler rations instead of corn starch is without adverse effects.

Amino Acids, Essential↗
PubMed1997

In vivo angiotensin II receptor blockade and converting enzyme inhibition on canine aortic viscoelasticity.

The influence of the renin-angiotensin system (RAS) on the aortic wall mechanical properties under angiotensin I converting enzyme inhibition (enalaprilat, 0.3 mg/kg iv) or angiotensin II receptor (AT1) blockade (E-3174, 1 mg/kg iv) was examined in eight normotensive and eight renovascular hypertensive conscious dogs. Aortic diameter (D; sonomicrometry)-pressure (P; microtransducer) hysteresis loops during steady state and during rapid distal aortic occlusion allowed (after hysteresis elimination) calculation of the aortic wall viscosity index, the purely elastic P-D relationship, and derivation into compliance-pressure curves. At the early stage ofrenovascular hypertension when activation of RAS is more pronounced, aortic wall stiffness and wall viscosity were increased as compared with normotensive states. Blood pressure remained unchanged in normotensive animals and was reduced during hypertension after antihypertensive treatments. In hypertensive animals, enalaprilat and E-3174 decreased viscosity index and shifted the compliance-pressure curve upward with respect to pretreatment conditions. In normotensive dogs, whereas E-3174 did not change the compliance-pressure curve and viscosity index, enalaprilat increased compliance and reduced viscosity index. We concluded that in normotensive dogs converting enzyme inhibition modifies arterial viscoelastic parameters by angiotensin-independent mechanisms that contribute to the modulation of the buffering function of large arteries.

Angiotensin I↗
PubMed1997

Fibrinogen and its relations to subclinical extracoronary and coronary atherosclerosis in hypercholesterolemic men.

The association between plasma fibrinogen and the presence of carotid, femoral, and aortic plaque (high-resolution B-mode ultrasonography) and coronary calcium deposit (ultrafast computed tomography scanner) was determined in 693 hypercholesterolemic, never-treated men free of previous or current clinical symptoms of cardiovascular disease. The number of subjects with extracoronary disease sites and coronary calcification deposits was significantly higher in the upper than in the lower tertile of fibrinogen. Plasma fibrinogen increased according to the number of diseased sites. The odds ratio of the upper to lower fibrinogen tertile for the presence of arterial lesions was 2.6 (1.7 to 4) for carotid, 2.2 (1.5 to 3.2) for aorta, 2.2 (1.5 to 3.1) for femoral, 1.8 (1.3 to 2.6) for coronary, and 3.6 (2.3 to 6.1) for one of four diseased sites. Adjustment for age, total cholesterol, HDL cholesterol, triglycerides, current smoking, and systolic pressure slightly reduced the association between fibrinogen and atherosclerosis. A synergistic effect between fibrinogen and total cholesterol/ HDL cholesterol (TC/HDL) ratio seemed to be operating on atherosclerosis, because nearly all of the individuals (98%) had a diseased site when fibrinogen and TC/HDL tertiles were the highest. This result suggests that fibrinogen is involved in the subclinical phase of extracoronary and coronary atherosclerosis and may potentiate the atherogenic effect of hyperlipidemia.

Adult↗
PubMed1997

A cystic fibrosis transmembrane conductance regulator splice variant with partial penetrance associated with variable cystic fibrosis presentations.

Some patients express various features of cystic fibrosis (CF) even though essential characteristics of the disease might be absent. Such patients may suffer from respiratory disease without pancreatic insufficiency and normal sweat chloride levels. Others may present as male infertility because of congenital bilateral aplasia of the vas deferens (CBAVD) with no other signs of CF. The 5T allele, a DNA variant in a noncoding region of the cystic fibrosis transmembrane conductance regulator (CFTR) gene that reduces the level of the normal CFTR transcripts, was found in increased frequency among male patients with CBAVD. The purpose of this study was to investigate the possibility that the 5T allele is associated with dysfunction of organs other than the male reproductive system, leading to CF or atypical CF. Analysis of the 5T allele was performed on 148 subjects (29 with CF, 61 with atypical CF, and 58 with CBAVD) carrying 232 chromosomes with unidentified CFTR mutations, and on 142 non-CF chromosomes from healthy subjects of Ashkenazi origin. The frequency of the 5T allele among chromosomes from patients of Jewish Ashkenazi origin with CF and atypical CF (six of 33; 18%) was significantly higher than the frequency in the normal Ashkenazi population (eight of 142; 6%; p = 0.03). Analysis of the clinical presentation of the five patients with CF and the 12 patients with atypical CF carrying the 5T allele indicated that most patients suffered from respiratory disease presenting as asthma like symptoms, nasal polyposis, chronic sinusitis, chronic bronchitis, or bronchiectasis. Six patients had pancreatic insufficiency, two with meconium ileus. Sweat Cl- levels ranged from normal to elevated. Of the six male patients with respiratory disease who were old enough to be evaluated for fertility status, five were fertile and one had pancreatic insufficiency. Among male patients with CBAVD, 41% suffered from respiratory symptoms. Thus, the 5T allele is a variant with partial penetrance causing disease with an extreme variability of clinical presentation: from normal healthy fertile subjects or male patients with CBAVD to those with atypical or typical clinical phenotype of CF.

Adolescent↗
PubMed1997

Plasma and erythrocyte vitamin E content in asymptomatic hypercholesterolemic subjects.

The present study was designed to assess plasma and erythrocyte vitamin E concentrations in 57 asymptomatic hypercholesterolemic (HC) men compared with 56 normocholesterolemic (NC) men. Vitamin E concentrations were determined by using a reversed-phase HPLC method. Compared with NC subjects, HC men had a significantly lower red blood cell (RBC) vitamin E content in spite of their normal plasma vitamin E concentration. This study demonstrates that total plasma vitamin E concentration is not a suitable predictor of cell vitamin E status and suggests an abnormal transfer of tocopherol between plasma and RBCs in HC men. Moreover, the RBCs of HC men were more susceptible to a peroxidative stress. The strong correlation between RBC susceptibility to oxidation and RBC vitamin E content suggests that the low RBC vitamin E content found in HC men has physiological consequences on the RBC oxidation.

Amidines↗
PubMed1997

[Ultrasonographic study of the arterial walls: application to the detection of preclinical atherosclerosis].

Ultrasonography of the arterial wall allows detection of structural (thickening, plaque) and/or functional (rigidity, reactivity) changes associated with preclinical atherosclerosis. Thickening of the arterial wall may be observed by measuring the intima-media thickness of the posterior wall of the common carotid or superficial femoral arteries. Hypertension, hypercholesterolaemia, diabetes and cigarette smoking induce carotid (and femoral) intima-medial thickening, the atherogenic nature of which however has not been clearly demonstrated. An atheromatous plaque results in a localised echogenic thickening which intrudes into the lumen and which may be assessed qualitatively by its presence or absence in peripheral arteries at risk of atherosclerosis (carotids, abdominal aorta, femorals). The number of these peripheral sites involved increases in parallel with the number of traditional risk factors in a given individual. The elasticity of the arterial walls may be evaluated at carotid or femoral levels by measuring systolo-diastolic distension by a technique known as "echotracking". The increased rigidity of the arterial wall observed in hypertension or diabetes is a marker of the sclerotic component of atherosclerosis. Arterial reactivity, dependent on changes in blood flow, is assessed by pulsed Doppler at the humeral and femoral arteries by changes in diameter induced by ischaemia/hyperameia. Changes in arterial reactivity are observed in hypercholesterolaemia even in the absence of atherosclerosis. Structural and functional changes detected by arterial ultrasonography and associated with atherosclerosis have a prognostic value which may contribute to a more accurate assessment of global vascular risk and may be useful in evaluating the efficacy of antihypertensive or lipid lowering therapy.

Arteriosclerosis↗
PubMed1996

Carotid artery and left ventricular structural relationship in asymptomatic men at risk for cardiovascular disease.

To determine whether a relationship between echographically assessed carotid artery and left ventricular (LV) structures existed in asymptomatic men at risk for cardiovascular disease, we evaluated carotid and LV parameters in 69 subjects (23-62 years) without LV hypertrophy. The right common carotid far wall intima-media thickness (IMT) was measured using an automated technique and the cross-sectional intima-media complex area (IMC-CSA) was calculated, assuming a circular profile of carotid wall layers, as (IMC-CSA = pi x IMT x (IMT + D)), D being the lumen diameter. LV mass was evaluated using the M-mode echocardiography. Among study subjects 30% were hypertensive, 67% hypercholesterolemic, 21% current smokers and 52% had a positive smoking history. In the study population LV mass correlated both with IMT (r = 0.54, P < 0.001) and IMC-CSA (r = 0.62, P < 0.001). In multivariate analysis LV mass was associated with IMC-CSA (P < 0.001), body mass index (P < 0.01), lifelong smoking dose (P < 0.01) and systolic blood pressure (P < 0.05), r2 = 0.58, P < 0.001. Therefore, IMC-CSA may be a clinically relevant independent indicator of LV mass even within its normal ranges.

Adult↗
PubMed1996

Primary structure of human 11-cis retinol dehydrogenase and organization and chromosomal localization of the corresponding gene.

The universal chromophore of visual pigments in higher animals is 11-cis retinaldehyde. The final step in the biosynthetic pathway generating this compound is catalyzed by 11-cis retinol dehydrogenase, a membrane-bound enzyme abundantly expressed in the retinal pigment epithelium of the eye. In this work we demonstrate that the primary structure of human 11-cis retinol dehydrogenase is highly conserved with 91% identity to the bovine enzyme. The gene encoding 11-cis retinol dehydrogenase spans over approximately 4.1 kb of DNA and is divided into four translated exons. Analysis of a panel of somatic cells hybrids and fluorescence in situ hybridization on metaphase chromosomes revealed that the gene is located on chromosome 12q13-q14. Due to the unique role of 11-cis retinol dehydrogenase in the generation of visual pigments, it is a candidate gene for involvement in hereditary eye disease.

Alcohol Oxidoreductases↗
PubMed1996

Inhibitory effect of ursolic acid on B16 proliferation through cell cycle arrest.

The effects of ursolic acid on the proliferation of B16, a mouse melanoma cell line, were studied. During investigations of the anti-proliferative effects of this triterpene, we observed that MTT colorimetric and colony forming assays show that ursolic acid is a potent inhibitor of B16 cell growth. Cell cycle analysis was performed by propidium iodide staining and flow cytometry technique. This triterpene exerts an early effect on cell cycle at G1, which explains its anti-proliferative activity. These results suggest that alterations in cell cycle phase redistribution of B16, by ursolic acid, may significantly influence the proliferation of B16, melanoma cells.

Animals↗
PubMed1996

Decreased erythrocyte deformability in glycogen storage disease.

Liver glycogen storage diseases (GSD) are disorders associated with severe dyslipidaemia which can induce cell membrane alterations and possibly reduced cell deformability. Since decreased erythrocyte deformability is known to disturb blood flow in capillaries and may promote ischaemic diseases, this study was designed to investigate erythrocyte deformability using a new filtration system, the Cell Transit Analyser (CTA), and to examine lipid compounds in the blood of 23 patients affected with GSD, aged from 1 to 20 years and 18 controls aged from 1 to 17 years. The patients showed a mixed hyperlipidaemia with predominant hypertriglyceridaemia and an increase in erythrocytes mean transit times (TT) due to the presence of more rigid erythrocytes subpopulations when compared to controls. Thus the erythrocyte rigidity, in addition to the lipid abnormalities must be taken into account for long-term evolution of GSD patients. Moreover this cellular alteration may contribute to shortened erythrocyte survival.

Adolescent↗
PubMed1996

The effects of prenatal exposure to cocaine on the dopaminergic cells in the rat retina. An immunocytochemical and neurochemical study.

There is a growing consensus that the development of the eye is affected by prenatal exposure to cocaine. Considering that the retina is affected by prenatal cocaine exposure, that this drug affects the dopaminergic systems, that the dopaminergic cells in the retina show a well-defined pattern of development and that they can be specifically stained in wholemounts by the antibody anti-tyrosine hydroxylase (TH), this study was undertaken to evaluate the effects of in utero cocaine exposure on the dopaminergic cells of the rat retina. Pregnant Wistar rats were given 60 mg (kg body weight)-1 day-1 of cocaine hydrochloride, subcutaneously, from gestational days 8 to 22. Control groups of pregnant rats were pair-fed. At PND14, 30 and 90, male offspring from different litters were perfused with fixative and the retinas processed as wholemounts and immunostained with the antibody anti-TH. Rats from other groups were decapitated at the same post-natal ages, the retinas dissected and processed by neurochemical techniques to measure the concentrations of dopamine, its metabolites and the turnover of dopamine. There was a significant increase of the retina surface area between PND14-30 in the control group, which was not found in the cocaine group. The density of the immunostained small TH cells was lower in the cocaine groups. No drug-effects were detected in the density of the large TH cells. The densities of the total large and small cells in the superior, inferior and nasal hemiretinas were similar to those found in the whole retinas; however, in the temporal hemiretinas of the cocaine groups, the density of the large TH cells was higher and of the small TH cells was lower than in controls, resulting in an absence of effects on the total density of TH-cells in this hemiretina. A transient increase in the level of dopamine metabolite (DOPAC) and of the turnover of dopamine at PND14 was detected in the cocaine groups. All quantitative parameters reached normal values, in all groups, at PND90. These results show that, during the critical periods in which catecholamines can influence the development of neurons, cocaine transiently affects the pattern of dopaminergic neurons in the retina. This may have functional importance due to the role of this neurotransmitter as a regulatory and/or trophic factor in developing neuronal circuitries.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Blood lipids and rheological modifications in glycogen storage disease.

OBJECTIVES: Hyperlipidemia is a feature of liver glycogen storage disease (GSD). Recent studies have suggested that rheological mechanisms such as elevated erythrocyte aggregation may be involved in the pathogenesis of ischemic syndromes associated with hyperlipidemia. DESIGN AND METHODS: We investigated erythrocyte aggregation, lipids, and circulatory proteins in the blood of 24 patients affected with GSD, aged from 1 to 23 years (mean = 8) and 26 controls aged from 1 to 28 years (mean = 9). RESULTS: The aggregation results were much higher in patients than controls. The lipid data showed a mixed hyperlipidemia with predominant hypertriglyceridemia, low HDL-C, apoA-I and LpA-I/A-II, and high apoB as compared with controls. However, the LpA-I was not significantly different from controls. CONCLUSIONS: In conclusion, patients with GSD presented hyperlipidemia and elevated erythrocyte aggregation such that they are at long-term risk of ischemic complications.

Adolescent↗