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b-Talassemia - Lipidoperoxidacao - Antioxidantes

By Maria Gertrudes Ferreira Gomes da Costa

Abstract

In general the first part of this study dealt with some of the theoretical considerations in relation to history, epidemiology, genetics, clinical and standard treatment of Homozygous b- Thalassemia, Major form, as followed in the Hematology Dept., Hospital D. Estefania. In the second part we decribe the alterations in the erythrocytic membrane in b-Thalassemia mechanism and importance of lipidoperoxidation, in this hemoglobinopathy outlining the action of antioxidant agents as membrane protectors. The last part of this research study is experimental. Twenty four patients were studied, 18 with homozygous bdeg Thalassemia, Major form, and 6 with the associated sickle-bdeg Thalassemia, most of them originating from Central and Southern Portugal, submited during one year to the standard treatment A and during the following year the standard treatment B, equal in all respects, (hypertranfusion programs, iron chelation, splenectomy and other side therapies), execpet in the simulteneous association of two antioxidant medications, Cantaxantine (oral daily dose of 50 to 70 mg) and Vitamin E (oral daily dose of 500 to 1.000 mg) administered in standard treatment B. The results obtained showed an important role of lipidoperoxidation in Thalassemia syndromes and a failure in physiological processes of control and resistance to tjhe free radicals produced in excess, in these clinical situations, that result in a diminishement of the half life of the erythrocytes and lead to an early hemolysis due to failure of membrane functions. We would also point out the benefits of the use of antioxidant medications, during treatment B, in the resistance to lipidoperoxidation present in these syndromes. We evaluated, as an indication of lipidoperoxidation, the erythrocytic MDA-the stable product resulting form lipidic breakdown of lipids from thelassemic erythrocytic membrane - the uricemia and the tocopherolemia. The results obtained from teatment Groups "a and B" and a Control Group of normal individuals, were analyzed using Student t test. The MDA levels, found in treatment Group A were significant much higher in relation to these of treatment group B [853,7 n moles/grHb-521,1 n moles/ grHb (p<0,0019] whereas no significant variations were observed betweem MDA levels of treatment group B and the control Group, [521,1 n moles/grHb-406,7 n moles/grHb(pNS)]. The levels of uricemie obtained from treatment Group A were significantly less than those of treatment Group B [3,7 mg/dl-4,9 mg/dl (p<0,001)]. No significant variations were found between observations of treatment B and the control Group [4,9 mg/dl 5,1 mg/dl (p-NS)]. The levels of tocopherolomie in treatment Group A were significantly lower in comparison to treatment Group B [0,18 mg/dl-1,34 mg/dl (p<0,001)] and also in relation to the control group [0,18 mg-0,71 mg/dl (p<0,0019]. The levels of the annual average /Hb were higher during treatment group B the average different being 1,44 hr/dl (annual average/Hb: 10,52 gr/dl in treatment A; 11,96 gr/dl in treatment group B), maintaining an equal annual use of blood, which is confirmed by the normalization of osmotic globular resistance, and an increase of the half-life erythricites, assessed by Cr"51 [half life 16,1 dyas for treatment group A and 20,8 days in treatment group B (p<0,001)]. We determined that the use of antioxidants during treatment B, originated a notable decrease of the lipidoperoxidation phenomenon, which is normally increased in all patients, proved by: - Normalization of the levels of the erythrocytic MDA in relation to the initial levels and to those of the normal individuals. - Increase of uricemie and tocopherolemie - Increase of the half-life of erythrocytes with consequent increase of the annual average hemoglobin, for an annual blood inatake main-taining the same quantities and frequencyAvailable from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1200 Lisboa / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga

Topics: 06A - Biochemistry
Year: 1986
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Provided by: OpenGrey Repository
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