Publications by authors named "David Gravell"

Objectives: This study aimed to evaluate the cause of thrombosis in Behçet's disease (BD) patients, since abnormalities in coagulation and fibrinolytic parameters have shown contradictory results.

Methods: Haemostatic parameters were retrospectively evaluated in BD patients treated between January 2007 and January 2011 at Sultan Qaboos University Hospital, Oman. The blood samples of 35 Omani BD patients and 30 healthy controls were analysed for factor VIII:C levels, activated protein C resistance (APCR), von Willebrand factor (vWF) antigens (Ag), collagen binding and ristocetin co-factor activity (RiCoF), antithrombin (AT), protein C (chromogenic and clotting), protein S, homocysteine, tissue plasminogen activator, plasminogen activator inhibitor, plasminogen, alpha 2-antiplasmin, lupus anticoagulant and anticardiolipin and beta2-glycoprotein-1 antibodies.

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We report the presence of two different dglobin gene mutations causing d?-thalassemia in association with homozygous (-a3.7/-a3.7) genotype for the first time in an Omani child with a low hemoglobin A2 (HbA2) of 0.

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Objectives: The aim of this study was to validate the interpretation of red blood cell indices in complete blood count (CBC) and high performance liquid chromatography (HPLC) results on cord blood samples in consecutive Omani neonates.

Methods: Cord blood samples from 7,837 neonates, were analysed with CBC and HPLC using the β-thalassaemia short programme. Direct sequencing of abnormal samples with HbS, HbD, HbE and HbC was performed to validate the HPLC results.

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Placental insufficiency resulting in fetal loss has been recognized in women with thrombophilic predisposition. Recent studies indicate that there is a high prevalence of protein Z (PZ) deficiency in patients with unexplained fetal loss. The objective of this study was to measure the PZ levels in pregnant Omani women in the first, second and third trimesters and correlate with the pregnancy outcome.

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A novel β-globin gene promoter (-71 C>T) nucleotide change was recently posted to the HbVar database (ID 2701) without precision on phenotype and ethnicity. We found the same change in compound heterozygosity with Hb S [β6(A3)Glu>Val] in an Omani family with almost equal expression of Hb A and Hb S. This suggested that the -71 C to T mutation may be a mild β-thalassemic allele.

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Hb A(2)' [δ16(A13)Gly→Arg], also called Hb B2, is a δ-globin chain variant that has been identified in several populations of African origin or ancestry and is easily identifiable in alkaline acetate cellulose electrophoresis as doubling of the Hb A(2) band. However, in high performance liquid chromatography (HPLC), commonly employed nowadays, it elutes in the S window. Over a period of 2 years at the Sultan Qaboos University Hospital, Muscat, Oman, we identified 25 Omanis with this variant.

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A novel β-globin structural variant, namely Hb Sheffield [β58(E2)Pro→His], was recently found as a sporadic event in a British Subject and posted to the HbVar database (ID 2672). Here we describe the same variant in 11 Omani subjects in the heterozygous state and in one Omani woman in compound heterozygosity with Hb S [β6(A3)Glu→Val]. Hb Sheffield coelutes in the Hb A(2) window in the high performance liquid chromatography (HPLC) system as does Hb E [β26(B8)Glu→Lys], and might be erroneously diagnosed as Hb E unless additional tests including DNA analyses are done.

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To evaluate the incidence of hemoglobinopathies in Omani subjects and to forecast its future burden on health resources, we initiated a prospective neonatal screening program in two major cities of the Sultanate of Oman. Consecutive cord blood samples from a total of 7,837 neonates were analyzed for complete blood counts and for hemoglobin (Hb) profile by high performance liquid chromatography (HPLC). No case with Hb H (beta4) was detected.

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Hb Dhofar is a variant haemoglobin (beta(29 (GGC-GGT) gly-gly), beta(58 (CCT-CGT) pro-arg)) associated with a thalassaemic phenotype and unique to the Sultanate of Oman. We report clinical and haematological data on 54 subjects with Hb Dhofar (37 heterozygotes, 14 homozygotes and three compound heterozygotes with a different beta-thalassaemia mutation). In heterozygotes, the level of Hb Dhofar ranged from 8.

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Several studies have provided reference ranges for the concentration of serum transferrin receptor (sTfR) in various white populations, but there is a dearth of relevant reference sTfR data in non-whites. The aim of this investigation was to establish sTfR reference ranges and mean values for a healthy non-white Arab population that could be used also for Arabs worldwide. sTfR and serum ferritin concentrations were estimated by immunoassays and blood counts were determined by conventional methods.

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Background: Haemoglobinopathies are a major cause of morbidity in the Sultanate of Oman and premarital screening is being encouraged in order to reduce the number of affected births. The identification of β-thalassaemia carrier status is an essential prerequisite of any screening programme. However, the level of Haemoglobin (Hb) A(2), which is used to detect β-thalassaemia carriers, can be affected by other factors including iron deficiency, concurrent α thalassaemia and the type of DNA mutation present.

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