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Biomedical subjects

R Olinescu

Publications and source records attributed to R Olinescu.

16 recordsLinked to original sources
PubMed1992

The negative impact of oxidative stress in chronic cardiac failure and coronary heart disease calls for a new pathophysiologic and therapeutic approach.

Oxidative stress, when associated with ECG aspects of "coronary disease", indicates an accelerated course of atherosclerosis in the onset phase (by cellular involvement, migration, proliferation, etc.) and an additional thrombogenic risk in the "ischemic disease" phase, when associated with chronic cardiac failure, it indicates a progressive form with "replacement fibrosis". The therapy that reduces the oxidative stress can slow down the physiopathologic process, and clinically improves the patients' condition and prognosis.

Adult↗
PubMed1991

Melatonin involvement in oxidative processes.

The fact that the pineal gland, by its melatonin (MT) production, responds to environmental light variations (the day-night cycle), being also a modulator of the body adaptation to these conditions, may lead to the assumption of its involvement in the body oxidative processes. The redox capacity of melatonin was followed-up in vitro by the chemiluminescence phenomenon. The system generating chemiluminescence as well as free radicals was made up of luminol and H2O2. Incubation of melatonin in doses of 0.08-0.5 microM/ml with the generating system showed that in doses under 0.25 microM/ml melatonin has a pro-oxidative effect while in doses above this value it has an antioxidative effect. The diagram of the results shows the answer specific to a modulator. The study of the correlation between the dose of melatonin with highest pro-oxidative properties and the various peroxide concentrations in the generating system showed that melatonin gets antioxidative properties with the increase in peroxide concentrations (less than 8 mM/ml). In the presence of a hypothalamic homogenate, which is a stimulant of the chemiluminescence-generating system (PXI = 16), melatonin has a dose-dependent antioxidative effect. Similar results were also obtained by adding tryptophan--a free radicals acceptor (PXI = 0.1) and the substrate in melatonin synthesis to the reaction medium. Melatonin in low concentrations (greater than 0.1 microM/ml) has an antioxidative effect while in higher doses it has a dose-dependent pro-oxidative effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

Endogenous biochemical factors affecting the efficiency of some radioprotective or radiosensitizing drugs: sulfhydryl groups and lipid peroxides.

The changes in the amounts of blood and tissular sulfhydryl groups and lipid peroxides were investigated in lethally gamma-irradiated rats treated with cystamine, AET (radioprotectors) or alpha-methyl-dopa (a radiosensitizer). The results of experiments revealed the following findings: 1. The ionizing radiation generally causes increases in the levels of tissular sulfhydryl groups and lipid peroxides (excepting the hepatic levels of these compounds). 2. AET and, especially, cystamine are able to reverse the radiation-induced changes in the tissular amounts of sulfhydryl groups and lipid peroxides; there are close relationships between this effect (including its intensity and extension) and the radioprotective action of these drugs. 3. In spite of its radiosensitizing action, alpha-methyl-dopa induces approximately similar changes in the tissular amounts of sulfhydryl groups and lipid peroxides, suggesting that biochemical processes other than an excessive yield of free radicals are also involved in radiosensitivity.

Animals↗
PubMedDate not supplied

Age-dependent variations of the plasma peroxides and total antioxidants in women with obesity and hypothyroidism.

The concentrations of peroxides, total antioxidants and free sulfhydryl (SH) groups in the plasma of normal persons vary depending on age and sex. The most significant differences for peroxides were found between young and old people over 60 years in both sexes. For the SH groups, significant differences were observed only between young and older women, while in men, similar differences were found only for total antioxidants. In women, the association of obesity with hypothyroidism induces a significant increase of peroxides even at the age of 35 years. This significant increase goes in parallel with a increase of uric acid and a decrease of the total antioxidants. Considering the inclusion of uric acid and of free SH groups among the natural antioxidants, the changes observed in obesity associated with hypothyroidism may suggest a tendency of an adaptation of the organism since hypothyroidism favors the peroxidation of lipids. Up to a certain age, varying according to the individuals, the rise of lipid peroxides is compensated by the increase of certain antioxidants, especially of uric acid.

Adult↗
PubMedDate not supplied

Induction of chemiluminescent emission in polymorphonuclear leucocytes stimulated by Sendai virus.

Sendai virus (SV) stimulates in vitro the chemiluminescent emission (CHL) of human polymorphonuclear leucocytes (LPMN). The kinetics of CHL produced by LPMN depends on the structure of stimulus, the intensity being dependent of the immunological status of the subject. CHL induced by Sendai virus is similar to that given by phorbol-myristate (PMA) as regards the induction of an early maximum. To obtain CHL significant emission, an optimum ratio between LPM concentration and Sendai virus dilution is required. The maximum effect is obtained in a large scale of dilution of Sendai virus ranging from 6,000 to 16,000 uHA.

Cells, Cultured↗
PubMedDate not supplied

Antiviral activity of some copper complexes of symmetrical triazines.

Copper complexes of hydrazones derived from symmetrical triazines inhibit the multiplication of three different types of viruses (Sendai, HSV and VSV) showing as well a scavenger activity on O2- radicals. The results emphasize the antiviral activity of these complexes which have at the same time a O2- radical scavenger activity.

Antiviral Agents↗
PubMedDate not supplied

Variations of peroxides and total antioxidants from the plasma of normal blood donors, as a function of sex, age and blood group.

The level of peroxides and total antioxidants in normal individuals varies with sex, age and the type of blood group. The most significant differences were noticed in peroxide between young and aged subjects (over 60) of both sexes. For the free SH groups, significant differences were found, only in women, in whom it decreased with age. Similar changes were observed in men for the total antioxidants. High peroxide values were observed in donors with blood group 0-I and the lowest levels appeared in subjects with blood groups A and B, in parallel with increased values of total antioxidants. The latter results might be correlated with recent data on favourable prognosis in cancer related to the expression of group A antigens, as well as with the involvement of the glycoproteins in the characterization of blood groups (AB0 system). Our data could also be correlated with the preventive role of antioxidants in the etiology of cancer.

Adult↗
PubMedDate not supplied

Comparative study of the variations of the phagocytic capacity of polymorphonuclear leukocytes and of total plasma antioxidants in patients with pneumoconioses and lung cancer.

A comparative, preliminary study of the phagocytic capacity of polymorphonuclear leukocytes, and of the total plasma antioxidants was carried out in a group of workers professionally exposed to mineral dusts and in a group of patients with lung cancer. Both groups exhibited advanced respiratory failure stages II and III. The phagocytic capacity of polymorphonuclear leukocytes was found significantly increased in workers with pneumoconioses and moderately increased in patients with lung cancer. On the other hand, the peroxides and total plasma antioxidants exhibited great individual variations. Thus in lung cancer it was observed that peroxides had a tendency to decrease and antioxidants to increase. The individual study of the variations of these three parameters might be able to differentiate the reversible from the irreversible stages of the respiratory changes.

Adolescent↗
PubMedDate not supplied

The changes of peroxides and total antioxidants in the plasma of patients who received 131I therapeutically.

Fifty patients with thyroid cancer were studied during administration of high doses of 131I (5-50 mCi). Peroxides, total antioxidants and free sulphydryl-groups were measured in the blood samples obtained before and after administration of radioactive iodine. After the administration of iodine, significant increases of peroxides and free SH groups were observed, as well as the decrease of total antioxidants. These biochemical changes were in agreement with significant decreases of blood platelets and lymphocytes. The data obtained brought forward again the much debated problem of peroxidation and antioxidants in cancer, since comparatively, the patients with other localizations of tumors presented decreases of peroxides and variable amounts of antioxidants. The influence of iodine and thyroid hormones is discussed, with reference to a previous paper in which high levels of peroxides had been found both in hyper- and in hypothyroidism but with different mechanisms. The biochemical changes observed in the patients treated with radioactive iodine confirmed the involvement of peroxides in the consequences of internal irradiation.

Adult↗
PubMedDate not supplied

Effects of some prostaglandins on the main phosphorylating, electron transporting and peroxidative systems of the erythrocyte membrane.

Investigations regarding the main biochemical systems of the erythrocyte membrane were performed on rat erythrocyte ghosts after treating the animals with PGA1, PGE1 and PGF2alpha. These investigations have shown that the prostaglandins which were found to induce changes in the erythrocyte flexibility (PGE1 and PGF2ALPHA) also induce significant changes in the concentrations of lipid peroxides, SH groups, proteins and nicotinamide adenine nucleotides, as well as in the activity of some electron transportors belonging to the nicotinamide proteins, in the erythrocyte membrane.

Adenine Nucleotides↗
PubMedDate not supplied

Evaluation of the therapeutic efficiency of Voltarene by using the in vitro chemiluminescence emitted by leukocytes polymorphonuclear.

It is known that antiinflammatory drugs inhibit the chemiluminescence produced by polymorphonuclear leukocytes (PMNL). In this respect, we studied in vitro, in standardized conditions (1.0 x 10(6) PMNL), the inhibitory effect of Voltarene on the chemiluminescence produced by PMNL from patients with rheumatic diseases, before and after treatment with the above drug. The stimulation index, as a quantitative measure of PMNL phagocytosis is higher in patients with rheumatic diseases than in controls. After treatment with Voltarene, the stimulation index further increases, especially in the patients with arthritis, suggesting a raised PMNL reactivity. A great differentiation of the in vitro inhibitory effect of Voltarene was observed especially for higher concentrations, function of age and the severity of disease. According to our results, Voltarene acts mainly by increasing the PMNL reactivity. The in vitro inhibitory effect of Voltarene on PMNL seems to be correlated with the in vivo action, the younger patients showing the greatest reactivity.

Adolescent↗
PubMedDate not supplied

The significance of the peroxides increase in the plasma of the patients with liver failure.

200 patients with varied types of liver failure were biochemically and clinically investigated. Beside the usual biochemical analyses (transaminases, glutamyl transpeptidase, triglycerides, bilirubin), some special parameters such as lipid peroxides, glutathione, ceruloplasmin and the total antioxidative capacity of plasma were measured. High levels of lipid peroxides appear especially in severe cases of liver failure such as acute viral hepatitis, coma. The persistence of a high level of peroxides in plasma suggests the presence of severe, irreversible lesions. The increase of peroxides in the plasma is mainly due to the overridden production of antioxidative systems, localized especially in the liver. In severe liver failure, the mechanism of the increased formation of peroxides seems to involve bilirubin, due to induction of liver heme oxygenase. The data presented showed inverse correlations between the increase of peroxides and the decrease of glutathione and ceruloplasmin.

Alanine Transaminase↗