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Biomedical subjects

T Onat

Publications and source records attributed to T Onat.

At least 19 recordsLinked to original sources
PubMed2000

Antioxidant enzyme activities and total nitrite/nitrate levels in the collar model. Effect of nicardipine.

There is a large body of literature describing the causative role of oxidative stress mediated by increased levels of reactive oxygen species in the pathogenesis of cardiovascular disease such as atherosclerosis, hypertension, and restenosis after angioplasty. The positioning of a soft silicone collar around the rabbit carotid artery elicits intimal thickening. The findings from recent studies demonstrated that both intimal thickening and atherosclerosis lead to synthesis of inducible nitric oxide synthase, resulting in abundant amounts of nitric oxide. We investigated the effects of collaring and nicardipine treatment on the activities of antioxidant enzymes, superoxide dismutase and catalase, and total nitrite/nitrate levels, stable products of nitric oxide. Placing the collar increased the total nitrite/ nitrate levels and decreased superoxide dismutase activity in collared arteries. Treatment with nicardipine (20 mg/kg/day, s.c.) prevented enhanced nitric oxide degradation without affecting superoxide dismutase and catalase activities. Our results suggest that enhanced nitric oxide production and superoxide anion are generated in response to the collaring, resulting in oxidative stress within the segment in this model.

Animals↗
PubMed1995

[Not Available].

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History, 20th Century↗
PubMed1994

Post-axial hexodactily and single atrium: a new syndrome?

A 3 1/2 year old boy is presented with postaxial hexodactily in all extremities, a persisting large left vena cava superior (VCS) draining into the left part of a single atrium and a mild dextroversio cordis. All extra fingers and the lateral parts of the fused metatarsals were amputated. At age 10, the cardiovascular anomalies were surgically corrected successfully by separating the atrium with a pericardial patch and by draining the left VCS to the right atrium with a graft. The patient seems to represent a new syndrome, since the combination of postaxial hexodactily with single atrium had previously been observed by the author in another patient in 1970.

Angiocardiography↗
PubMed1994

Ethanol induced oxidative stress and membrane injury in rat erythrocytes.

The aim of this study was to observe membrane injury and to investigate the mechanism of antioxidant defence systems against acute ethanol toxicity. Erythrocyte superoxide dismutase and Na+, K(+)-ATPase activities were significantly decreased and catalase levels were significantly increased one hour after ethanol intoxication of male swiss albino rats. These data demonstrated that superoxide dismutase and catalase are susceptible to lipid peroxidation and that these enzymes protect tissues from free radicals. The possible mechanism involved in Na+, K(+)-ATPase and Ca(2+)-ATPase inhibition are discussed in relation to the development of ethanol toxicity and the role of lipid peroxidative processes.

Alcoholic Intoxication↗
PubMed1992

[Lupus anticoagulant and antiphospholipid antibody values in a family with systemic lupus erythematosus].

The Lupus Anticoagulant (LA) is an immunoglobulin directed towards the phospholipid portion of the prothrombin activator complex. This immunoglobulin because first identified in the plasma of patients with Systemic Lupus Erythematodes, was named as Lupus Anticoagulant. Although initially described in patients with SLE, it was subsequently observed in other diseases and also in patients without any manifest disease. SLE or similar diseases are present in 35% of LA (+) patients. The LA prevalence in SLE patients has been found as 34% whereas ACA prevalence was found as 44%. While searching for the presence of LA and the levels of APA in cases having unexplained recurrent fetal losses, a family (a mother and 3 daughters) was discovered, whose each member has been diagnosed as SLE at different times and with different symptoms. Data suggesting the presence of LA and high APA levels were determined in all the members of the family and also it was realised that cause who had recurrent fetal losses had the highest APA levels. In addition to immunoassay methods to detect APA, examination of coagulation tests in patients with unexplained thrombosis and/or fetal losses, would be of great help.

Abortion, Habitual↗
PubMed1990

Serum and aqueous humor sialic acid levels in Behçet's disease.

Serum and aqueous humor sialic acid (SA) levels were determined in 27 patients with Behçet's disease (Bd). Serum SA levels were elevated significantly during the active episode (mean, 113.4 +/- 4.12 mg/dl) and in the remission stages (mean, 85.4 +/- 4.79 mg/dl; P less than 0.001). A significant increase was also detected in active episodes when compared to chronic stages (P less than 0.02). Aqueous humor levels were also evaluated but could only be determined in the six eyes at the end-stage of the disease (mean, 2.65 +/- 0.60 mg/dl; P less than 0.05).

Acute Disease↗
PubMed1984

Discrete subaortic stenosis as part of a short stature syndrome.

Observations in a family point to the existence of autosomal dominant inheritance for discrete subaortic stenosis (DSS), which made up part of a multisystem disorder. Both parents, offspring of two full siblings, had short stature, obstructive lung disease (OLD), hoarseness and upturned nose. The father alone had aortic stenosis and inguinal hernia. The six offspring, aged from 13 to 28 years, were followed up for up to 8 years. While one of them was virtually normal, and one had only minor abnormalities, four siblings displayed clinical signs of progressive aortic stenosis. Of the two eldest siblings who eventually died, necropsy in one showed a discrete subaortic stenosis, which was hemodynamically proven in one and surgically corrected in another sibling. Upturned nose was present in each examined member of the family, short stature and hoarseness in five of the siblings, DSS in four, OLD, inguinal hernia and congested episcleral veins in three, kyphoscoliosis in two, while epicanthus, strabismus, microphthalmos and widely spaced teeth were noted in the deceased female. The prevalence of some of these traits in roughly three-quarters of the sibship was consistent with an underlying single gene abnormality in affected heterozygous parents. We proposed that this constitutes a new syndrome.

Adolescent↗
PubMed1979

The relationship between somatic growth and psychological development in Turkish adolescents.

The relationship between somatic and psychological development, such as intellectual capacity, introversion--extroversion, neuroticism and anxiety, has been investigated with the aid of 148 Turkish adolescents and preadolescents from a middle-level school in Istanbul. The results revealed no relationship between the rate of somatic growth and psychological development. The level of parental cultural environment seemed to have a certain influence upon the degree of intellectual capacity to the disadvantage of those originating from lower levels. The present findings obtained from this study lead to the conclusion that the variations of psychological characteristics in adolescents may not be accepted as only due to factors within the organism, such as the tempo and degree of somatic development independent of cultural, environmental effects, but that a more intensive investigation of also the external, social-environmental factors is necessary.

Adolescent↗