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Biomedical subjects

A Sima

Publications and source records attributed to A Sima.

52 records · Page 3Linked to original sources
PubMedDate not supplied

The hyperlipemic hamster - a model for testing the anti-atherogenic effect of amlodipine.

Male Golden Syrian hamsters were subjected to a hyperlipemic diet. At intervals ranging from 2 to 14 weeks, the animals were examined for changes in serum constituents and structural modifications of lesion-prone areas: the cardiac valves, coronary arteries and aortic arch. Serum was characterized by a gradual increase in cholesterol, triglycerides and a decrease in total peroxyl-radical trapping potential. The sequence of modifications of the endothelial cells, smooth muscle cells, and migrating plasma monocytes as well as of the extracellular matrix were established. Amlodipine treatment of hyperlipemic hamster was assessed. Amlodipine exhibited an athero-protective effect, acting as antioxidant, reducing the LDL uptake by the vessel wall and consequently, limiting the size and extent of lesioned areas. The hyperlipemic hamster is a reliable model to unravel the cellular alterations leading to atheroma formation, and for testing the effect of drugs in this process.

Amlodipine↗
PubMedDate not supplied

The total peroxyl radical trapping potential in serum - an assay to define the stage of atherosclerosis.

Lipid peroxides were identified among the factors that contribute to the atherosclerotic plaque formation in the arterial wall. We hypothesised that a correlation may exist between the content of antioxidant constituents in the serum and the gravity of atherosclerosis. To this purpose, we have determined the serum total peroxyl radical- trapping potential (TRAP), which is the combined capacity of all antioxidants to neutralize free radicals in serum and followed its variation in hyperlipemic animals in correlation with the stage of atherosclerosis. In addition, we compared TRAP values in the sera of coronary heart disease (CHD) patients, with or without type II diabetes mellitus. Results showed that after 18 weeks of hyperlipemic diet, the mean TRAP values measured in sera isolated from hyperlipemic hamsters exhibited an about 44% decrease, in good agreement with the increase of serum cholesterol and triglycerides. In the 3 groups of CHD patients, TRAP values decreased with about 10% in sera of stable angina patients, 20% in unstable patients, as compared with normal subjects. The lowest TRAP values were detected in the sera of patients with acute myocardial infarction. The results obtained for different experimental animals and for CHD patients sera indicate that the TRAP method, as adapted in our laboratory, is a reliable and reproducible assay, fit to be used in clinical studies as an ex vivo measurable parameter that correlates with the stage of the atherosclerosis.

Animals↗
PubMedDate not supplied

Statins: mechanism of action and effects.

The beneficial effects of statins are the result of their capacity to reduce cholesterol biosyntesis, mainly in the liver, where they are selectively distributed, as well as to the modulation of lipid metabolism, derived from their effect of inhibition upon HMG-CoA reductase. Statins have antiatherosclerotic effects, that positively correlate with the percent decrease in LDL cholesterol. In addition, they can exert antiatherosclerotic effects independently of their hypolipidemic action. Because the mevalonate metabolism generates a series of isoprenoids vital for different cellular functions, from cholesterol synthesis to the control of cell growth and differentiation, HMG-CoA reductase inhibition has beneficial pleiotropic effects. Consequently, statins reduce significantly the incidence of coronary events, both in primary and secondary prevention, being the most efficient hypolipidemic compounds that have reduced the rate of mortality in coronary patients. Independent of their hypolipidemic properties, statins interfere with events involved in bone formation and impede tumor cell growth.

Cholesterol Esters↗
PubMedDate not supplied

[Imported tropical parasitosis in Rumania].

The frequency of intestinal parasitoses among subjects coming from warm countries is high and its range is similar to that found by other parasitologists in Europe as well as by those who made investigations in groups of individuals in various warm countries. Bearing in mind the pathogenous role--even limited--of certain parasites, their systematic detection and the treatment of every individual infested with parasites appears necessary. The hereby investigations point out the importance of a complex coproparasitologic examination and the high efficiency of some special diagnosis methods. Every laboratory must perform in rarallel several ovoscopic and larvoscopic methods of investigation in view of an accurate parasitologic diagnosis or for a prophylactic control of subjects coming from warm countries. The high frequency of ankylostomiasis raises peculiar problems related to its systematic detection and its compulsory treatment up to the parasitologic sterilization, bearing in mind the past evolution in Rumania of an underground focus, which does not exist any more, having been entirely eradicated.

Ancylostomiasis↗
PubMedDate not supplied

Pseudotumor cerebri: risk factors, clinical course, prognostic criteria.

UNLABELLED: Eighty-five patients with the diagnosis of pseudotumor cerebri were retro- and prospectively studied. For clinical evaluation, the following criteria were used: neurological--headache, ophthalmological--visual acuity, visual field, ophthalmoscopy and psychic--memory. Each patient was assigned 2 categories of results expressed by: neuropsychic and ophthalmological scores which were statistically processed. The following conclusions related to the aim of our paper can be drawn: I. RISK FACTORS: pregnancy (8% of cases), obesity (15%), generalized infections or located in the pelvic region+operated on (6%), hormonal treatment (cortisol (12%), estrogens (6%)); II. The clinical course was significantly favourable for: headache (51% of cases), defects of visual acuity (54%) and papilledema (63%). The long-lasting effects of the treatment applied showed: recovery (for the 2 parameters) in 27% of patients and improvement with sequelae for one and/or the other parameter in 73% of the cases; III. Among the more significant prognostic criteria were the ophthalmological symptoms and signs at onset of the disease. The ophthalmological sequelae (visual acuity, visual field defects, chronic papilledema and optic atrophy) are important factors in the prognosis of the disease and represent predictors for the surgical management.

Follow-Up Studies↗
PubMedDate not supplied

Catamnestic study of cases with tardive decompensated hydrocephalus.

One hundred patients with decompensated hydrocephalus (60 operated, 40 nonoperated) were studied both retrospectively and prospectively at 3 moments of the disease course. The indicators were clinical: neurologic, psychic and social, and paraclinical: results of pneumoencephalography, encephalography, radioisotope cisternography. The effects of surgical treatment (ventriculocardiac derivation) and of medical treatment were evaluated at short and long term. In surgical treatment, favourable short-term outcome (headache, gait and micturition disorders, improved consciousness, psychomotor activity, social behaviour) was found in 88% of the patients; long-term favourable outcome was present in 60% of the patients and implied only the psychic and social indicators. In medical treatment the favourable short-term outcome was nonsignificant and the long-term outcome was favourable in only 32% of the patients. In the remaining cases evaluated as unfavourable, the cognitive disorders increased progressively. The predictors for favourable therapeutic outcome were: early diagnosis, early surgical intervention, the clinical form of hydrocephalus, the sequelae and short-term effects of surgical treatment.

Adult↗
PubMedDate not supplied

The interaction between human low density lipoproteins and bovine aortic endothelial cells. Measurements of membrane fluidity.

Bovine aortic endothelial cells in culture have been incubated with human low density lipoproteins (LDL) characterized in their cholesterol content. The incubation was done at different time intervals up to 72 h and various LDL concentrations. It began after endothelial cells had been starved for 24 h in lipoprotein deficient serum. The transfer of some LDL-components to endothelial cells plasmalemma was monitored by measurements of membrane fluidity. Namely, the fluorescent probe trimethylamonio-diphenyl hexatriene was inserted in the cell membrane and fluorescence anisotropy was determined; a higher fluorescence anisotropy means a higher rigidity of the plasmalemma. The results show that the rigidity of the endothelial cell plasmalemma increased progressively with the time of incubation (+11% to +19.5% after 24 h and 72 h, respectively for the concentration of 200 micrograms. LDL-cholesterol/dish) and with the greater amount of cholesterol in LDL (+10.9%) for 200 micrograms LDL-cholesterol/dish to +15% for 800 micrograms LDL-cholesterol/dish after 24 h incubation). In order to see if the LDL material transfer proceeded by receptor-mediated endocytosis of LDL and/or directly through aqueous solution a lysosomal inhibitor, chloroquine, was used at the concentration of 20 microM for preventing the lysosomal hydrolase activity. In the presence of this inhibitor the fluorescence anisotropy in treated endothelial cells increased by a lesser amount, suggesting an approx. 30% participation of intracellular route. Therefore, the transfer of material (probably cholesterol) from LDL to endothelial plasmalemma could take place both by receptor-mediated endocytosis and directly through the aqueous solution.

Animals↗
PubMedDate not supplied

Correlated biochemical modifications of plasma lipoproteins in coronary heart disease: an accelerating pathologic factor.

We investigated the presence of biochemically modified plasma lipoproteins as pathologic factor for coronary heart disease in 15 patients with angina pectoris (CHD-P) vs 20 normal subjects (N). Decreased HDL were the most significant pathological feature present in P over 66 years old, while, P under 66 had, in addition to low HDL-Cholesterol (HDL-C), high levels of plasma cholesterol (C), LDL-Cholesterol (LDL-C), and lipid peroxides (TBARS), together with the presence of desialylated LDL and VLDL. We demonstrated by statistic analysis that these risk factors are correlated: high plasma C with a more pronounced imbalance between LDL and HDL, which, in turn, is associated with high TBARS levels, and also with circulating desialylated VLDL; high plasma TBARS values with desialylated LDL. We detected an increased level of autoantibodies towards autologous LDL and VLDL, in P vs N. The level of autoantibodies anti-LDL correlated with LDL-C level and with LDL desialylation, thus modified circulating LDL being most probably atherogenic. Circulating anti-LDL autoantibodies together with the low level of HDL might contribute to acceleration and aggravation of the atherosclerotic process.

Adult↗
PubMedDate not supplied

[Tetanus in Libreville: hospital analysis of 30 cases].

We investigated 34 cases of tetanus in patients younger than 75 years old in Libreville. We found that the incidence of tetanus was 8 cases for every million people. The disease mostly affected people younger than 50 (85%). Only two neonatal tetanus cases were reported. The death rate was 74%, despite the availability of intensive care and respiratory assistance. We stress the benefits of tetanus immunization, which must be continued, and suggest the use of intrathecal serotherapy for the cure of tetanus in Libreville.

Adolescent↗
PubMedDate not supplied

Immunodetection of modified lipoproteins in plasma and arterial walls of patients with coronary heart disease.

Data from literature indicate that immune processes play an important role in atherogenesis. Modified lipoproteins might be immunogenic and generate autoantibodies in plasma. To determine whether the level of such circulating autoantibodies correlates with the extent of atherosclerosis expressed as cholesterol values in plasma (C), very low density (VLDL-C), low density (LDL-C), and high density lipoproteins (HDL-C), we compared the level of plasma autoantibodies of a group of coronary heart disease patients (CHD-P) with that of normal, age-matched donors, with no history of cardiac disease (N). All CHD-P (even normocholesterolemic) were characterized by an LDL-C/HDL-C ratio > 4, while all N (even hypercholesterolemic) had this ratio < 4. A double level of circulating autoantibodies against VLDL and LDL in CHD-P as compared to N group was detected. The anti-LDL antibodies level correlated well with LDL-C level and was negatively correlated with the age of patients. For tissue localization of native and modified LDL (as well as other possibly modified proteins) we used immunohistochemical techniques, employing antihuman LDL, antihydroxynonenal-lysine (HNE-Lys), and antiadvanced glycation end-products (AGE) proteins. Antibodies were applied on consecutive cryosections of the aortic arch, valves and coronary arteries of CHD-P. The immunodetected antigens were colocalized in focal deposits, in the cap and shoulders of the atheroma. Native LDL and modified proteins (AGE, HNE-Lys) were detected either diffuse-extracellularly or associated with macrophage-derived foam cells and smooth muscle cells of the intima. These data indicate the following: a) the existence of an elevated level of circulating autoantibodies against VLDL and LDL, which correlates negatively with the age of CHD patients; b) the presence of LDL (possibly glycated or oxidized) in detectable amounts in the intima of atherosclerosis-affected arteries; c) the modified lipoproteins are immunoactive components in the atherosclerotic process.

Aged↗