Diagnosis of Glanzmann thrombasthenia by whole blood impedance analyzer (MEA) vs. light transmission aggregometry.

BACKGROUND: Glanzmann thrombasthenia (GT) is a rare inherited platelet disorder that is characterized by spontaneous or postprocedural bleeding. The diagnosis of GT depends on identifying the dysfunction of the platelets. AIM: The aim of this study was to compare a whole blood impedance Multiplate analyzer (MEA) with the standard method, light transmission aggregometry (LTA) in diagnosis of GT. METHODS: Fifteen patients with GT were assessed on MEA and LTA using arachidonic acid (ASPI: 15 mm), (TRAP: 1 mm), collagen (100 µg/mL), ADP (0.2 mm), and ristocetin (Risto: 10 mg/mL). Whole blood samples were collected in sodium citrate and hirudin vacuum, blood collection tubes and tested within 4 h. Platelet-rich plasma was used for LTA using platelet agonists (ristocetin 1.5 mg/mL) (arachidonic acid 0.5 mg/mL) (ADP 2.5 mg/mL) and (collagen 1 mg/mL). RESULTS: The platelet count and PFA-100 results were (average and SD) 319 ± 93 × 10(9) L and 252 ± 34 s, respectively. Flow cytometry analysis showed that all samples are positive for CD42a and CD42b, whereas 9/15 samples were negative for CD61 and CD41. The other six patients had either partial or full expression of CD61/CD41. Aggregation analysis using both methods showed that all samples had no aggregation response to any of the agonists used apart from six samples which, using only the MEA, showed minimal aggregation in response to collagen (average = 14.3 ± 7 µg, which may suggest ability to detect qualitative abnormality of GPIIb/IIIa). CONCLUSION: These results suggest that the MEA is sensitive for the detection of Glanzmann thrombasthenia. Furthermore, MEA may also be able to differentiate between the subtypes of Glanzmann thrombasthenia.

Incremental layer shear bond strength of low-shrinkage resin composites under different bonding conditions.

The purpose of this study was to determine the incremental shear bond strength of a silorane-based composite (Filtek Silorane) repaired with silorane or a methacrylate-based composite (Filtek Z250) under various aging conditions. Also, the incremental bond strength of the silorane-based composite was compared with that of another low-shrinkage methacrylate-based composite (Aelite LS Posterior) under fresh and aged conditions, with and without the use of an adhesive resin between successive layers. The two brands of low-shrinkage composites were compared with a microhybrid, Filtek Z250, which served as the control. Substrate discs were fabricated and second layers were adhered to them immediately, after two weeks of aging, or after four weeks of aging and with and without an adhesive resin. Shear bond strengths were measured and failure modes were evaluated. The incremental bond strength of silorane to the silorane-based composite was not significantly different from that of the methacrylate-based composite. However, repairing a silorane-based composite with a methacrylate-based composite significantly reduced the bond strength. Aelite showed a lower incremental bond strength than Z250 and silorane, but the use of an adhesive significantly improved the bond strength. The absence of an oxygen-inhibited layer did not affect the bond strength of the consecutive layers of the silorane-based composite.

Watermelon chlorotic stunt virus (WmCSV): a serious disease threatening watermelon production in Jordan.

The incidence of watermelon chlorotic stunt disease and the molecular characterization of the Jordanian isolate of Watermelon chlorotic stunt virus (WmCSV-[JO]) are described in this study. Symptomatic leaf samples obtained from watermelon (Citrullus lanatus Thunb.), melon (Cucumis melo L.), squash (Cucurbita pepo), cucumber (Cucumis sativus L.), and bottle gourd (Lagenaria siceraria) plants were tested for WmCSV-[JO] infection by PCR. The virus could be detected in 8 melon and 87 watermelon samples obtained from Ghor Assafi (southern part of Jordan Valley). Three samples collected from Mafraq (eastern part of Jordan) were found mixed infected with WmCSV-[JO] and Squash leaf curl virus. The full-length DNA-A and DNA-B genomes of WmCSV-[JO] were amplified, and sequences were deposited in the GenBank under accession numbers EU561237 and EU561236, respectively. Sequence analysis reveals that WmCSV-[JO] is closely related to other virus isolates from Israel (WmCSV-[IL]), Yemen (WmCSV-[YE]), Iran (WmCSV-[IR]), Lebanon (WmCSV-[LB]), and Sudan (WmCSV-[SD]). DNA-A of WmCSV-[JO] showed highest nucleotide identity (99.42%) with WmCSV-[IL], while DNA-B had highest nucleotide identity (95.52%) with WmCSV-[YE]. Data of this study demonstrate that digestion of DNA-B genome of WmCSV isolates with ApaI enzyme can discriminate between these isolates at the molecular level. Infectious clones of WmCSV-[JO] were constructed and agroinoculated to Nicotiana benthamiana plants. Inoculated plants developed mild disease symptoms 4 weeks post inoculation, while watermelon plants biolistically inoculated with WmCSV-[JO] developed characteristic mottling, yellowing and severe leaf curling symptoms 3 weeks post inoculation.

Allogeneic stem cell transplantation in patients with ß-thalassemia: King Faisal specialist hospital and research centre experience.

From January 1998-July 2006, 62 stem cell transplantation (SCT) were performed on 60 patients with beta-thalassemia from HLA-related match donors. The overall survival (OS) and event free survival (EFS) for all patients were 94 and 77%. The outcome of allogeneic SCT in our experience is satisfactory with OS 92% and EFS 77%. Transplantation at a young age and when the disease is mild offers the best outcome. More advanced disease is associated with higher rate of rejection and severe graft versus host disease.

Allogeneic stem cell transplantation in a patient with dyskeratosis congenita after conditioning with low-dose cyclophosphamide and anti-thymocyte globulin.

Bone marrow failure is the major cause of early mortality in patients with dyskeratosis congenita (DC); early trials with conventional conditioning regimens were associated with remarkable chronic morbidity and mortality, and the optimal conditioning regimen for these patients remains undetermined. We report a case of a child afflicted with DC who underwent related full HLA-matched stem cell transplant (SCT) using a regimen of low dose cyclophosphamide and antithymocyte globulin (ATG). The regimen was well tolerated and associated with no significant short-term toxicity.

Extramedullary myeloid tumors in children: the limited value of local treatment.

PURPOSE: To determine the incidence of extramedullary tumors (EMT) in Saudi Arabian children with acute myeloid leukemia, the factors associated with these tumors and the impact of local treatment on local tumor control, complete remission and survival rates. PATIENTS AND METHODS: One hundred children, median age 6 years, who received their primary treatment for acute myeloid leukemia at King Faisal Specialist Hospital and Research Center, from 1983 to 1997 were studied. EMT at diagnosis occurred in 18 (18%) patients at 25 sites. Meningeal leukemia, hepatosplenomegaly, lymph node enlargement, gingival hypertrophy, and cutaneous infiltration were not included in the definition of EMT. With these exclusions, children with EMT were younger than those without EMT (median age, 3.5 v. 7.5 years) and were more likely to have meningeal leukemia at diagnosis (33% v. 10%). The t(8;21) translocation was associated with a 47% EMT incidence compared with 23% without the translocation. Local radiation treatment was given to 16 of 25 (64%) EMT sites. RESULTS: The overall 5-year survival rate for all patients was 28%, and this was not significantly influenced by the drug regimen used, meningeal leukemia at diagnosis, the presence of the (8;21) translocation, M4 and M5 morphology combined, or EMT at diagnosis. Significant differences were observed in the 5-year survival rates for patients who underwent allogeneic bone marrow transplantation (52%; N = 37) and those who attained complete remission (CR) but did not undergo transplantation (21%; N = 44) and those who did not achieve complete remission with initial therapy (5%; N = 19). Systemic and local EMT CR was achieved in 17 of 18 patients with EMT, including 12 patients who underwent radiation treatment and 5 of 6 of those who did not. Isolated relapse was not seen at an EMT site and was not noted at any later stage of the disease. CONCLUSIONS: Permanent local control at sites of EMT was achieved in all patients who attained a bone marrow CR, whether or not the site was irradiated. Local radiation treatment of an EMT site did not appear to contribute to overall CR and survival rates. The use of radiation treatment should be conservative and limited to patients in whom there is a real and immediate threat to vision or renal function or when the spinal cord is compromised.

Central venous access devices in children with hemophilia: an update.

The most frequent indication for placement of a central venous access device in hemophiliacs is in very young boys (ages 1-2 years) with severe hemophilia who are started on a program of long-term factor prophylaxis designed to eliminate target joint bleeding and the development of chronic musculoskeletal disease. Although expensive, this strategy is extremely successful. It involves intravenous infusion of 25-40 factor units per kg on alternate days (minimum 3 times a week) for boys with severe hemophilia A, and twice a week for boys with severe hemophilia B. To facilitate this prophylaxis regimen some hemophilia clinics routinely recommend placement of a central venous access device; others, more concerned about associated complications such as sepsis, stress the importance of using peripheral veins wherever possible, with central access devices reserved for occasional, selected cases only. A decision to use such a device should only be made after discussion of the risks/benefits with parents (or guardians) and with patients if of an appropriate age. If such a system is to be used, we recommend that a totally implantable device (Port-A-Cath) be placed because of the lower risk of infection, and because totally implantable devices allow children to take part in activities such as swimming. Important complications include catheter-related sepsis, which may occur in 25% or more of devices over time and, much less frequently, catheter-related deep vein thrombosis.

Prenatal diagnosis and management of neonatal alloimmune thrombocytopenia.

Neonatal alloimmune thrombocytopenia (NAIT) is an uncommon (1 in 2,000 livebirths) but serious disorder characterized by marked thrombocytopenia in the fetus and neonate. Platelet destruction is caused by a maternal antibody directed against a fetal platelet antigen inherited from the father and lacking in the mother's platelets. Intracranial hemorrhage (ICH) is the most devastating complication of NAIT, affecting approximately 20% of all proven cases, up to 50% of which occur antenatally. Because close to 100% of subsequent pregnancies will be equally or more severely affected, antenatal management directed at preventing ICH in utero has assumed great clinical importance. In recent years, considerable progress has been made in this regard, and although clinical uncertainties still exist, the natural history of this disease and its response to various antenatal interventions have become reasonably well understood. This review will focus on the diagnosis and current management of NAIT, including controversies surrounding current treatment modalities and future prospects for treatment and prevention.

Central venous access catheters in children with haemophilia.

Twenty-five central venous lines (two external 23 subcutaneous ports) were placed in 19 boys with haemophilia A (n = 17) or B (n = 2). The mean age of the boys was 4.9 years (range 0.2-15.3 years). The haemophilia was severe (factor level < 1%) in 18 boys and moderate (factor level 3%) in one. Three boys had circulating inhibitors and three were positive for human immunodeficiency virus (HIV)-1 antibody. Central venous lines were placed to facilitate intermittent factor replacement therapy (n = 6), long-term factor prophylaxis (n = 9), induction of an immune tolerance protocol (n = 2) or therapy for acquired immunodeficiency syndrome (AIDS)-related complications (n = 2). The ports remained in place for 15795 days (mean 687 days, range 11-2059 days). The frequency of port-related sepsis was 48% (11/23 ports in eight boys) or 0.7 port infections per 1000 patient days. Ports were removed from five boys with an unresolved infection (four with Staphylococcus aureus sepsis and one with Pseudomonas sp. sepsis). Other complications requiring port removal included a catheter tip placed too high in the venous system (n = 1), severe persistent pain associated with needle access of the port (n = 1) and a subclavian vein thrombosis (n = 1). Both the benefits and risks of a subcutaneous port should be considered when deciding whether to place this device in a very young child with haemophilia.