A multi-center study in order to further define the molecular basis of beta-thalassemia in Thailand, Pakistan, Sri Lanka, Mauritius, Syria, and India, and to develop a simple molecular diagnostic strategy by amplification refractory mutation system-polymerase chain reaction.

The spectrum of the beta-thalassemia mutations of Thailand, Pakistan, India, Sri Lanka, Mauritius and Syria has been further characterized by a multi-center study of 1,235 transfusion-dependent patients, and the mutations discovered used to assess the fidelity of a simple diagnostic strategy. A total of 44 beta-thalassemia mutations were identified either by allele-specific oligonucleotide hybridization, amplification with allele-specific primers, or DNA sequencing of amplified product. The results confirm and extend earlier findings for Thailand, Pakistan, India, Mauritius and Syria. This is the first detailed report of the spectrum of mutations for Sri Lanka. Two novel mutations were identified, codon 55 (-A) and IVS-I-129 (A-->C), both found in Sri Lankan patients. Two beta-thalassemia mutations were found to coexist in one beta-globin gene: Sri Lankan patients homozygous for the beta0 codon 16 (-C) frameshift were also homozygous for the beta+ codon 10 (C-->A) mutation. Studies of Sri Lankan, Pakistani, and Indian carriers suggest the codon 10 (C-->A) mutation is just a rare polymorphism on an ancestral allele, on which the beta0 codon 16 (-C) mutation has arisen. Each country was found to have only a few common mutations accounting for 70% or more of the beta-thalassemia alleles. A panel of primers to diagnose the majority of the mutations by the amplification refractory mutation system was developed, enabling a simple molecular diagnostic strategy to be introduced for each country participating in the multi-center study.

Molecular characterization of beta-thalassemia in Syria.

This study concerns the determination of beta-thalassemia alleles and other hemoglobin variants in 82 patients from Syria. We have characterized 146 chromosomes and found 17 different beta-thalassemia mutations, and one beta-globin chain variant that gives rise to the abnormal Hb S. The eight most common beta-thalassemia mutations were the IVS-I-110 (G-->A), IVS-I-1 (G-->A), codon 5 (-CT), -30 (T-->A), codon 39 (C-->T), IVS-I-6 (T-->C), IVS-II-1 (G-->A), and codon 15 (TGG-->TAG). These mutations accounted for almost 75% of the total beta-thalassemia chromosomes. We identified 34 different genotypes with a high level of homozygosity. The various beta-thalassemia mutations were characterized using gene amplification with specific oligonucleotide primers, restriction enzyme analysis, denaturing gradient gel electrophoresis and direct sequencing. By combining these three approaches we were able to detect mutations in almost 90% of the chromosomes studied. Our findings provide a sound foundation on which to base a preventive program for thalassemia and we believe that the data that we present will facilitate the improvement of medical services such as carrier screening, genetic counseling, and prenatal diagnosis. Furthermore a detailed knowledge of the molecular pathology of beta-thalassemia will strongly improve the prenatal diagnosis services in Syria.

Catalase evaluation in different human diseases associated with oxidative stress.

OBJECTIVE: Catalase is an enzyme present in most of the aerobic cells, it protects them from oxidative stress by catalyzing the rapid decomposition of hydrogen peroxide (H2O2) in two types of reactions depending on its peroxidatic and catalatic activities. The aim of this study was to measure the erythrocytes catalase activity by a reliable method in normal subjects with different age categories, and patients whom suffer from different diseases associated with oxidative stress (inflammatory, tumor, diabetes, cardiovascular diseases, anemia and Wilson's disease). METHODS: Erythrocytes catalase activity was measured, by peroxidatic method (Johansson-Borg method), in 210 apparently healthy subjects, (117 males and 93 females). The range of their ages was from 7 months to 65 years, and in 454 patients their ages ranged from 3 months to 74 years, whom suffer from the above mentioned diseases which resulted in oxidative stress. The comparison had been made between the Johansson-Borg and the UV catalase methods. RESULTS: Strong correlation was found between the two methods, peroxidatic and catalatic (r=0.99, P<0.0001), but the catalase solutions were unstable when the temperature was raised. The normal range of catalase was found to be 2869+1039 u/g Hb. It was found that the catalase activity increased in the studied morbidity groups (eg. 188% in oxidative anemia). An accepted decrease 50% was noted in catalase activity when Vitamin E was administered to anemic patients suffering from oxidative stress. CONCLUSION: There was an increase in catalase activity in all studied patients suffering from oxidative stress (cardiovascular diseases, diabetes, tumor, inflammation, dermatological diseases, anemia and Wilson's disease). The catalase activity was not affected by age, sex or the anticoagulant agent, which was used to collect the blood samples. It was found that the Vitamin E supplement decreased the catalase activity and improved the state of anemic oxidative stress patients.

Relationship between serum leptin and obesity.

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