Rapid and simultaneous typing of hemoglobin S, hemoglobin C, and seven Mediterranean beta-thalassemia mutations by covalent reverse dot-blot analysis: application to prenatal diagnosis in Sicily

The molecular lesions causing beta-thalassemia in Sicily can be subdivided into two groups. One that occurs at a 71% frequency and consists of the beta 39, IVS 1,110 and IVS 1,6 mutations and the other group at a 20% frequency comprising the -87, beta s, IVS 1,1 and IVS 2,745 mutations. The identification of all these mutations by polymerase chain reaction (PCR) and conventional dot-blot hybridization has been time consuming and expensive. In this article, we describe the implementation of the reverse dot-blot (RDB) hybridization as a rapid nonradioactive method for the identification of the nine most frequent molecular lesions in the beta-globin gene (-87, beta s, beta c, IVS 1,1, IVS 1,6, IVS 1,110, beta 39, IVS 2,1, IVS 2,745) in Sicily. Sixty prenatal diagnoses were performed by this RDB assay, each of which was confirmed by dot-blot/ASO hybridization; thus demonstrating the accuracy of the RDB. The main advantage of this assay is the rapid typing of an individual's DNA for many mutations in a single working day. Because the mutations in this assay are representative for the Mediterranean region, this mutational panel can also be extended to the screening of beta-thalassemia from other Mediterranean regions.     

Inhibition of tissue factor/factor VIIa activity in plasma requires factor X and an additional plasma component

A study was carried out to explore requirements for the inhibition of tissue factor-factor VIIa enzymatic activity in plasma. Reaction mixtures contained plasma, 3H-factor IX or 3H-factor X, tissue factor (vol/vol 2.4% to 24%), and calcium. Tissue factor-factor VIIa activity was evaluated from progress curves of activation of factor IX or factor X, plotted from tritiated activation peptide release data. With normal plasma, progress curves exhibited initial limited activation followed by a plateau indicative of loss of tissue factor-factor VIIa activity. With hereditary factor X-deficient plasma treated with factor X antibodies, progress curves revealed full factor IX activation. Adding only 0.4 micrograms/mL factor X (final concentration) could restore inhibition. Inhibition was not observed in purified systems containing 6% to 24% tissue factor, factor VII, 0.5 micrograms/mL, factor IX, 13 micrograms/mL, and factor X up to 0.8 micrograms/mL, but could be induced by adding barium-absorbed plasma to the reaction mixture. Thus, both factor X and an additional material in plasma were required for inhibition. The amount of factor X needed appeared related to the concentration of tissue factor; adding more tissue factor at the plateau of a progress curve induced further activation. These results also indicate that inhibited reaction mixtures contained active free factor VII(a). Preliminary data suggest that inhibition may stem from loss of activity of the tissue factor component of the tissue factor- factor VII(a) complex.     

Pediatric Transplantation in the United States, 1996–2005

Solid organ transplantation is accepted as a standard lifesaving therapy for end-stage organ failure in children. This article reviews trends in pediatric transplantation from 1996 to 2005 using OPTN data analyzed by the Scientific Registry of Transplant Recipients. Over this period, children have contributed significantly to the donor pool, and although the number of pediatric donors has fallen from 1062 to 900, this still accounts for 12% of all deceased donors. In 2005, 2% of 89 884 candidates listed for transplantation were less than 18 years old; in 2005, 1955 children, or 7% of 28 105 recipients, received a transplant. Improvement in waiting list mortality is documented for most organs, but pretransplant mortality, especially among the youngest children, remains a concern. Posttransplant survival for both patients and allografts similarly has shown improvement throughout the period; in most cases, survival is as good as or better than that seen in adults. Examination of immunosuppressive practices shows an increasing tendency across organs toward tacrolimus-based regimens. In addition, use of induction immunotherapy in the form of anti-lymphocyte antibody preparations, especially the interleukin-2 receptor antagonists, has increased steadily. Despite documented advances in care and outcomes for children undergoing transplantation, several considerations remain that require attention as we attempt to optimize transplant management.     

Fetal intracranial teratoma: US diagnosis of three cases and a review of the literature

We describe three cases of fetal intracranial teratoma diagnosed by ultrasound and review the literature. Sonographic features include cranial enlargement, gross distortion of normal cerebral architecture by a hyperechoic, multicystic mass, and polyhydramnios. Despite early diagnosis, the cesarean section rate is high and the overall prognosis is dismal.