Gene frequency of human platelet alloantigens-1 to -6 and -15 in Saudi blood donors.

BACKGROUND: Human platelet antigens (HPAs) are involved in the pathogenesis of several clinical conditions, such as platelet transfusion purpura (PTP), refractoriness to platelet transfusion and neonatal alloimmune thrombocytopenia (NAITP). Typing of HPA (1-6 and 15) has not been carried on the Saudi population. This is the first study of all the seven HPA systems on Arabs. The aim of this prospective study was to determine the frequency of HPA (1-6 and 15) in Saudis. STUDY DESIGN AND METHODS: A total of 100 randomly selected Saudi blood donor samples were genotyped using the polymerase chain reaction with sequence-specific primers (PCR-SSP). RESULTS: The most common HPA genotypes among Saudis were HPA-1 a + b- (75%), HPA-2 a + b- (62%), HPA-3 a + b- (51·5%), HPA-4 a + b- (99%), HPA-5 a + b- (76·5%), HPA-6 a + b- (100%) and HPA-15 a + b + (50%). The prevalent allele among the HPA systems was (a), except in the HPA-15 system where the (b) allele was found in 52% of the subjects. Comparisons with other ethnic populations uncovered marked differences in the distribution of HPA alleles. CONCLUSION: Studying the prevalence of HPA antigens in Saudi population will help in the understanding of its role in platelet-related disorders. It will also enable the blood bank to establish an HPA-based donor registry that will be a valuable source of compatible platelet-therapeutic products to alloimmunised patients. This will also enhance the safety and efficacy of platelet transfusion. This data obtained will form an addition to the existing body of literature in transfusion research.

Plasma homocysteine levels in cardiovascular disease, malaria and protein-energy malnutrition in Sudan.

This study investigated the role of hyperhomocysteinaemia as a risk factor in Sudanese adults suffering from cardiovascular disease or malaria and children with protein-energy malnutrition. Mean total plasma homocysteine levels (micromol/L) were significantly higher in patients with coronary heart disease (17.64; SD 11.68) recurrent venous thrombosis (5.06; SD 10.55) and recurrent malaria (13.61; SD 4.82) than in healthy adult controls (7.85; SD 3.39). The mean homocysteine level was also significantly higher in children with protein-energy malnutrition (8.41; SD 1.61) than in healthy control children (5.72; SD 1.99).

Plasma homocysteine levels in cardiovascular disease, malaria and protein-energy malnutrition in Sudan

This study investigated the role of hyperhomocysteinaemia as a risk factor in Sudanese adults suffering from cardiovascular disease or malaria and children with protein-energy malnutrition. Mean total plasma homocysteine levels [micro mol/L] were significantly higher in patients with coronary heart disease [17.64; SD 11.68] recurrent venous thrombosis [5.06; SD 10.55] and recurrent malaria [13.61; SD 4.82] than in healthy adult controls [7.85; SD 3.39]. The mean homocysteine level was also significantly higher in children with protein-energy malnutrition [8.41; SD 1.61] than in healthy control children [5.72; SD 1.99]

Retinal periphlebitis resembling frosted branch angiitis with nonperfused central retinal vein occlusion.

PURPOSE: To report the unusual association between severe retinal periphlebitis resembling frosted branch angiitis and nonperfused central retinal vein occlusion (CRVO). METHODS: Observational case reports. RESULTS: Patient 1 was a 28-year-old man who presented with extensive sheathing involving all retinal veins in one eye followed by nonperfused CRVO. Twenty-seven months after initial presentation, he developed perfused CRVO in the other eye followed by periphlebitis that progressed into nonperfused CRVO. Patient 2 was a 47-year-old man who presented with unilateral severe retinal periphlebitis associated with nonperfused CRVO. Despite systemic administration of corticosteroid therapy, rubeosis iridis developed in both patients and neovascular glaucoma developed in Patient 1 despite full panretinal photocoagulation. Extensive systemic workup and coagulation studies were unremarkable except for the presence of antiphospholipid antibodies in both patients and elevated plasma homocysteine level in Patient 2. CONCLUSIONS: Severe retinal periphlebitis complicated by nonperfused CRVO is associated with poor visual outcome despite appropriate medical and surgical treatment.

Hyperhomocysteinemia and retinal vascular occlusive disease.

PURPOSE: Elevated plasma homocysteine is an independent risk factor for thrombosis and vascular disease. This prospective study compared plasma total homocysteine levels in patients with retinal vascular occlusive disease and in matched healthy controls. METHODS: We measured plasma total homocysteine in 56 consecutive patients with recently diagnosed retinal vascular occlusive disease: 36 had central retinal vein occlusion, 12 branch retinal vein occlusion, and 8 retinal artery occlusion, and compared them with 59 age- and sex-matched healthy controls. Homocysteine levels were determined by high-performance liquid chromatography with electrochemical detection. Hyperhomocysteinemia was defined as a plasma homocysteine level above the 95th percentile in the control group (13.6 micromol/L). RESULTS: Mean plasma total homocysteine levels were significantly higher in patients than controls (16.1 +/- 8.3 vs. 8.96 +/- 5.6 micromol/L p < 0.001). Mean homocysteine levels were significantly higher in the retinal vein occlusion and retinal artery occlusion groups than the control group (15.3 +/- 8.2 and 20.95 +/- 6.9 vs 8.96 +/- 5.6 micromol/L, p < 0.001). Estimates of the relative risk indicated that the risk of hyperhomocysteinemia was significantly higher in patients with retinal vascular occlusive disease than controls. Hyperhomocysteinemia was present in 37 (66.1%) of the 56 patients with retinal vascular occlusive disease but only 2 (3.4%) controls (odds ratio [OR] 47.5, 95% confidence interval [CI] 9.8-149.9). Hyperhomocysteinemia was present in 29 (60.4%) of the patients with retinal vein occlusion (OR 43.5, 95% CI 8.77-141.93) and in 6 (75%) patients with retinal artery occlusion (OR 85.5, 95% CI 7.49-1,173.1). CONCLUSIONS: High plasma homocysteine is a risk factor for retinal vascular occlusive disease so it may be useful to measure homocysteine in the management of these patients. A randomized, controlled trial is required to study the effect of lowering with homocysteine folic acid and other B vitamins on the risk of recurrent vascular occlusion in the same eye or its development in the fellow eye.