International Journal of Hematology

International Journal of Hematology | Vol. 4, No. 2, February 2013 | pp. 9–16
DOI: 10.46882/2013/IJH/000038

Original Article

Title: Assessment of hemostatic parameters and microparticle generation in stored whole blood units

Names of Authors: Q. S. Abubakar¹, U. T. Maina²

Authors’ Affiliations: ¹Department of Haematology, National Hospital, Abuja, Nigeria; ²Department of Pathology, Bayero University, Kano, Nigeria

Abstract: Blood storage lesions involve functional degradation and the accumulation of procoagulant cellular microparticles over time. This study analyzed sequential alterations in coagulation factors, platelet function, and microparticle generation in 50 whole blood units collected in citrate-phosphate-dextrose-adenine anticoagulant and stored at 4 °C for 35 days. Serial samples collected at days 1, 7, 14, 21, 28, and 35 measured factor VIII, factor V, prothrombin time, and erythrocyte-derived microparticles using flow cytometry. Factor VIII activity fell by 55.4% by day 14 and reached a low of 18.2% on day 35 (P < 0.01). Factor V activity exhibited a similar decline, decreasing by 42.1% by day 21. Concurrently, concentrations of procoagulant erythrocyte microparticles increased six-fold by day 28, correlating with a shortening of the baseline plasma clotting time in vitro (r = -0.52, P < 0.05). These results indicate that while labile coagulation factors decline rapidly, whole blood units accumulate highly procoagulant microparticles during storage. This supports the use of fresh whole blood (< 7 days stored) for correcting active coagulopathies, while older units may contribute to a prothrombotic risk in vulnerable recipients.

Keywords: Whole blood storage, factor VIII, blood storage lesion, microparticles, coagulation

Manuscript Timeline: Received: November 12, 2012; Revised: December 20, 2012; Accepted: January 10, 2013; Published: February 15, 2013

International Journal of Hematology | Vol. 4, No. 6, June 2013 | pp. 41–48
DOI: 10.46882/2013/IJH/000042

Original Article

Title: Evaluation of thrombopoietin receptor expression and reticulated platelets in chronic immune thrombocytopenia

Names of Authors: G. M. Babalola¹, I. N. Nwosu², K. S. Abubakar³

Authors’ Affiliations: ¹Department of Haematology and Blood Transfusion, Lagos University Teaching Hospital, Lagos, Nigeria; ²Department of Pathology, University of Nigeria, Nsukka, Nigeria; ³Department of Pathology, Bayero University, Kano, Nigeria

Abstract: Mechanisms driving thrombocytopenia in chronic immune thrombocytopenia include both accelerated platelet clearance and impaired megakaryocyte production. This study evaluated the relationship between surface thrombopoietin receptor (MPL) expression on platelets, plasma thrombopoietin levels, and the percentage of circulating reticulated platelets in 48 adult patients with chronic immune thrombocytopenia. Flow cytometry quantified thrombopoietin receptor density and thiazole orange-positive reticulated platelets, while plasma thrombopoietin was measured via enzyme-linked immunosorbent assay. Patients with immune thrombocytopenia exhibited an elevated mean percentage of reticulated platelets (14.6 ± 3.8%) compared to healthy controls (3.2 ± 0.9%, P < 0.001), reflecting increased bone marrow thrombopoietic activity. However, surface thrombopoietin receptor expression density on immune thrombocytopenia platelets was reduced by 52.4% relative to controls. Plasma thrombopoietin concentrations were only mildly elevated (mean 42.6 ± 12.4 pg/ml), which is inappropriately low for the degree of thrombocytopenia. The downregulation of surface thrombopoietin receptors combined with blunted plasma thrombopoietin responses highlights an underlying defect in megakaryocyte stimulation. These findings support using thrombopoietin receptor agonists to overcome relative bone marrow insufficiency in patients refractory to immunosuppressants.

Keywords: Immune thrombocytopenia, thrombopoietin receptor, reticulated platelets, megakaryopoiesis, flow cytometry

Manuscript Timeline: Received: March 08, 2013; Revised: April 14, 2013; Accepted: May 10, 2013; Published: June 19, 2013

International Journal of Hematology | Vol. 3, No. 2, February 2012 | pp. 9–16
DOI: 10.46882/2012/IJH/000026

Original Article

Title: Association between plasma von Willebrand factor antigen levels and vaso-occlusive crises in sickle cell nephropathy

Names of Authors: E. F. Chinedu¹, G. H. Haruna², I. J. Balogun³

Authors’ Affiliations: ¹Department of Haematology, University of Nigeria Teaching Hospital, Enugu, Nigeria; ²Department of Medicine and Nephrology, Lagos State University Teaching Hospital, Ikeja, Nigeria; ³Department of Chemical Pathology, University of Ilorin, Ilorin, Nigeria

Abstract: Endothelial activation and microvascular dysfunction drive the development of sickle cell nephropathy. This case-control study investigated the association between plasma von Willebrand factor antigen levels, microalbuminuria, and the frequency of acute painful crises in 80 patients with sickle cell anemia (HbSS) and 40 healthy hemoglobin AA controls. Plasma von Willebrand factor antigen concentrations were quantified using an enzyme-linked immunosorbent assay. Patients with sickle cell anemia exhibited significantly higher steady-state von Willebrand factor antigen levels (184.5 ± 32.4%) compared to controls (94.2 ± 12.6%, P < 0.001). Among the sickle cell cohort, patients with microalbuminuria (urine albumin-to-creatinine ratio 30 to 300 mg/g) showed a substantial elevation in von Willebrand factor antigen levels compared to those with normoalbuminuria (212.6% versus 161.4%, P < 0.01). Furthermore, von Willebrand factor antigen levels correlated positively with the annual frequency of vaso-occlusive crises (r = 0.54, P < 0.01). Elevated plasma von Willebrand factor antigen acts as a biomarker for endothelial stress, correlating with microvascular renal injury and severe vaso-occlusive phenotypes in sickle cell disease.

Keywords: Sickle cell nephropathy, von Willebrand factor, endothelial activation, microalbuminuria, vaso-occlusive crisis

Manuscript Timeline: Received: November 02, 2011; Revised: December 14, 2011; Accepted: January 05, 2012; Published: February 14, 2012

International Journal of Hematology | Vol. 3, No. 6, June 2012 | pp. 41–48
DOI: 10.46882/2012/IJH/000030

Short Communication

Title: Baseline activated partial thromboplastin time and prothrombin time reference intervals in a healthy adult population

Names of Authors: B. C. Akpan¹, D. E. Usman²

Authors’ Affiliations: ¹Department of Haematology, University of Calabar, Calabar, Nigeria; ²Department of Clinical Pharmacology, Ahmadu Bello University, Zaria, Nigeria

Abstract: Coagulation screening reference intervals vary due to differences in reagent sensitivities, instrumentation, and local population characteristics. This study established local reference intervals for prothrombin time and activated partial thromboplastin time in 120 healthy, non-pregnant adult blood donors and hospital staff aged 18 to 50 years. Plasma samples were analyzed on an automated coagulation analyzer using standard thromboplastin and actin reagents. The computed 95% reference intervals for prothrombin time were 11.2 to 14.5 seconds (mean = 12.8 ± 0.8 seconds). For activated partial thromboplastin time, the reference interval was 28.4 to 40.2 seconds (mean = 34.3 ± 2.9 seconds). No significant differences were observed across gender or age groups (P > 0.05). These calculated local ranges differed from manufacturer package inserts, which tended to underestimate upper limits. Establishing population-specific reference intervals prevents the over-investigation of healthy individuals and improves the accuracy of pre-operative coagulation assessments.

Keywords: Prothrombin time, activated partial thromboplastin time, reference intervals, coagulation, blood donors

Manuscript Timeline: Received: March 18, 2012; Revised: April 25, 2012; Accepted: May 14, 2012; Published: June 20, 2012

International Journal of Hematology | Vol. 3, No. 4, April 2012 | pp. 25–32
DOI: 10.46882/2012/IJH/000028

Original Article

Title: Evaluation of bleeding scores and platelet aggregation profiles in patients with suspected von Willebrand disease

Names of Authors: Q. S. Abubakar¹, U. T. Maina²

Authors’ Affiliations: ¹Department of Haematology, National Hospital, Abuja, Nigeria; ²Department of Pathology, Bayero University, Kano, Nigeria

Abstract: Characterizing von Willebrand disease phenotypes requires a combination of clinical bleeding standardized assessment scores and functional platelet aggregation studies. This study evaluated 55 patients presenting with unexplained mucocutaneous bleeding, menorrhagia, or recurrent epistaxis using the International Society on Thrombosis and Haemostasis bleeding score instrument. Laboratory assays quantified von Willebrand factor antigen levels, ristocetin cofactor activity, and platelet aggregation responses to ristocetin, adenosine diphosphate, and collagen. A high bleeding score (≥ 4 in males, ≥ 5 in females) was recorded in 41.8% (23 of 55) of the patients. Reduced ristocetin cofactor activity (< 30 IU/dl) and impaired ristocetin-induced platelet aggregation confirmed von Willebrand disease in 12.7% (7 of 55) of the cases, all consistent with Type 1 or Type 2 phenotypes. Bleeding scores correlated inversely with ristocetin cofactor functional activity values (r = -0.48, P < 0.05). Utilizing standardized clinical bleeding scores helps prioritize high-risk patients for advanced, specialized diagnostic platelet aggregation profiles.

Keywords: von Willebrand disease, bleeding score, ristocetin cofactor, platelet aggregation, menorrhagia

Manuscript Timeline: Received: January 08, 2012; Revised: February 18, 2012; Accepted: March 10, 2012; Published: April 15, 2012

International Journal of Hematology | Vol. 3, No. 8, August 2012 | pp. 57–64
DOI: 10.46882/2012/IJH/000032

Original Article

Title: Efficacy and safety of standard-dose versus low-dose low-molecular-weight heparin for venous thromboembolism prophylaxis in orthopedic surgery

Names of Authors: G. M. Babalola¹, I. N. Nwosu², K. S. Abubakar³

Authors’ Affiliations: ¹Department of Haematology and Blood Transfusion, Lagos University Teaching Hospital, Lagos, Nigeria; ²Department of Orthopaedic Surgery, University of Nigeria, Nsukka, Nigeria; ³Department of Pathology, Bayero University, Kano, Nigeria

Abstract: Major orthopedic procedures carry an exceptionally high risk of deep vein thrombosis, requiring robust pharmacological prophylaxis. This randomized controlled trial compared the efficacy and safety of standard-dose enoxaparin (40 mg subcutaneously daily) versus a low-dose regimen (20 mg subcutaneously daily) in 140 adult patients undergoing total hip or knee arthroplasty. Prophylaxis was initiated 12 hours post-operatively and maintained for 14 days. Objective screening using venous duplex ultrasonography was performed on day 14. The incidence of deep vein thrombosis was 4.3% (3 of 70) in the standard-dose group and 11.4% (8 of 70) in the low-dose group (P = 0.12). However, major bleeding episodes, defined by a hemoglobin drop exceeding 2.0 g/dl or requiring transfusion, were significantly higher in the standard-dose cohort (7.1% versus 0.0% in the low-dose cohort, P < 0.05). Minor wound hematomas occurred in 15.7% of standard-dose patients. While standard-dose enoxaparin provides numerically superior antithrombotic protection, the low-dose regimen demonstrates a significantly reduced bleeding risk. Clinicians should carefully weigh individual bleeding risks against thrombotic factors when selecting prophylactic doses in indigenous orthopedic patients.

Keywords: Deep vein thrombosis, enoxaparin, thromboprophylaxis, arthroplasty, hemorrhage

Manuscript Timeline: Received: May 05, 2012; Revised: June 15, 2012; Accepted: July 02, 2012; Published: August 14, 2012