Polymorphisms in Factor II and Factor V thrombophilia genes among Circassians in Jordan.

Thrombosis is a major cause of morbidity and mortality worldwide. Genetic factors are one component of thrombosis. We studied the prevalence of two mutations that are known risk factors in the pathogenesis of arterial and venous thrombosis in the genetically isolated Circassian population in Jordan. Factor II G20210A and Factor V Leiden single nucleotide polymorphisms were analysed by polymerase chain reaction and restriction fragment length polymorphism method in 104 random unrelated subjects from the Circassian population in Jordan. The prevalence rates among the Circassian population in Jordan for Factor II G20210A was 12.2% and for Factor V Leiden was 7.7%. We have shown that the population is in Hardy-Weinberg equilibrium and that the prevalences of both mutations are within the range of other ethnic groups. This is the first study to describe Circassian health related genetic characteristics in Jordan. Such population-based studies will contribute to understanding the interaction between genetic and environmental risk factors. It will remain to be seen whether carriers of Factor II G20210A and Factor V Leiden are more likely to develop thrombosis. This issue should be studied in the future to determine the need for screening of these mutations particularly in thrombophilia patients.

A neural network approach for predicting and modelling the dynamical behaviour of cardiac ventricular repolarisation.

Physiological signals are usually patient specific, and they are difficult to predict, especially for the cardiovascular system. New methods capable to be adapted to each case and to learn the singular behavior of heart functions should be developed to support physicians in their decision-making. One of the most widely studied relations is the QT-RR one, between the total duration of the ventricle activation and inactivation, and the heart rate. In the past, different studies were made to approach this relation in the steady state. In this paper, a new method for modeling and predicting the transient dynamic behaviour of QT interval in relation to changing RR intervals is presented using artificial neural networks.

A single amino acid, glu146, governs the substrate specificity of a human dopamine sulfotransferase, SULT1A3.

Sulfation, catalyzed by members of the sulfotransferase (SULT) superfamily, exerts considerable influence over the biological activity of numerous endogenous and xenobiotic chemicals. In humans, catecholamines such as dopamine are extensively sulfated, and a SULT isoform (SULT1A3 or the monoamine-sulfating form of phenolsulfotransferase) has evolved with considerable selectivity for dopamine and other biogenic amines. To investigate the molecular basis for this selectivity, we identified a region of SULT1A3, which, we hypothesized, contributes to its preference for biogenic amines, and mutated two amino acids within this domain to the corresponding residues in a closely related but functionally distinct phenol sulfotransferase, SULT1A1 (H143Y and E146A). The change of a single amino acid, E146A, was sufficient to transform the catalytic properties and substrate preference of SULT1A3, such that they closely resembled those of SULT1A1. These experiments confirm the functional role of Glu146 in the selectivity of SULT1A3 for biogenic amines and suggest that this region is a key determinant of sulfotransferase substrate specificity.

Lead-glazed pottery: a potential health hazard in the Middle East.

Lead-glazed pottery produced by obsolete methods in Lebanon and other countries in the Middle East is potentially hazardous when used in contact with acidic foods. This conclusion was deduced from the testing of 423 glazed utensils for the amount of lead leached by 4% acetic acid. Control measures, surveillance, and regulations are therefore warranted.

Disinfection of oral rehydration solutions by sunlight.

PIP: The use of a salt/sugar oral solution for rehydration in cases of diarrhea is being encouraged by the World Health Organization for developing areas. 1 problem so far with this treatment has been a question as to their safety when prepared with contaminated water or stored in contaminated vessels. An experiment was tried in which the recommended solution was mixed with contaminated water. Some of the containers were exposed to direct sunlight, some kept in the dark, and some stored in normal room conditions. Although the heat in the containers stored in sunlight did not rise significantly, the solutions were found to be purified. It is speculated that the germicidal action resulted from solar radiation near the ultraviolet range. The solution, itself, did not change composition. The microorganisms were not able to regrow within 24 hours after solar irradiation. 50 additional experiments confirmed the findings. It is concluded that this technique of solar irradiation of contaminated solutions will be effective. All types of containers were effective.^ieng

Outcome after posthemorrhagic ventriculomegaly in comparison with mild hemorrhage without ventriculomegaly.

The neurodevelopmental sequelae in 33 low birth weight neonates with moderate or severe hemorrhage and ventriculomegaly (VM group) and in 39 neonates with mild hemorrhage only (non-VM group) were evaluated prospectively. Both groups were comparable in birth weight, gestational age, and socioeconomic status. Ventriculoperitoneal shunts were inserted in 23 of the 33 VM group infants at a mean age of 26 days. Eighty-two shunt revisions were performed, for obstruction (71 revisions) or infection (11 revisions), in 18 of the 23 children. At a mean age of 50 months, 19 of 33 children in the VM group had sequelae; 14 children had moderate or severe neurologic deficits, and 5 children had mild sequelae. In the non-VM group, only 3 of 39 children had deficits, all of which were mild (p less than 0.05). In the VM group, 19 of 33 children had mental developmental delay in comparison with 8 of 39 in the non-VM group (p less than 0.05), and 17 of 33 children in the VM group had motor developmental delay in comparison with 5 of 39 in the non-VM group (p less than 0.01). Within the VM group, the number of children with neurodevelopmental sequelae did not differ significantly among the 23 children with shunts, in comparison with the 10 who did not require shunting. Among the children with shunts, a higher incidence of sequelae occurred when lack of ventricular decompression was noted immediately after shunt insertion (p less than 0.005) and when shunt infections occurred (p less than 0.01). The most important predictor of mental and motor outcome in the group with shunts was lack of ventricular decompression immediately after shunt insertion. We speculate that, in some infants, loss of brain tissue, cerebral atrophy, or both may occur before insertion of the ventriculoperitoneal shunt, even when the shunt is inserted early.

Crystal structure of glycogen synthase kinase 3 beta: structural basis for phosphate-primed substrate specificity and autoinhibition.

Glycogen synthase kinase 3 beta (GSK3 beta) plays a key role in insulin and Wnt signaling, phosphorylating downstream targets by default, and becoming inhibited following the extracellular signaling event. The crystal structure of human GSK3 beta shows a catalytically active conformation in the absence of activation-segment phosphorylation, with the sulphonate of a buffer molecule bridging the activation-segment and N-terminal domain in the same way as the phosphate group of the activation-segment phospho-Ser/Thr in other kinases. The location of this oxyanion binding site in the substrate binding cleft indicates direct coupling of P+4 phosphate-primed substrate binding and catalytic activation, explains the ability of GSK3 beta to processively hyperphosphorylate substrates with Ser/Thr pentad-repeats, and suggests a mechanism for autoinhibition in which the phosphorylated N terminus binds as a competitive pseudosubstrate with phospho-Ser 9 occupying the P+4 site.

Kinetic properties of human dopamine sulfotransferase (SULT1A3) expressed in prokaryotic and eukaryotic systems: comparison with the recombinant enzyme purified from Escherichia coli.

Sulfation, catalyzed by members of the sulfotransferase enzyme family, is a major metabolic pathway which modulates the biological activity of numerous endogenous and xenobiotic chemicals. A number of these enzymes have been expressed in prokaryotic and eukaryotic systems to produce protein for biochemical and physical characterization. However, the effective use of heterologous expression systems to produce recombinant enzymes for such purposes depends upon the expressed protein faithfully representing the "native" protein. For human sulfotransferases, little attention has been paid to this despite the widespread use of recombinant enzymes. Here we have validated a number of heterologous expression systems for producing the human dopamine-metabolizing sulfotransferase SULT1A3, including Escherichia coli, Saccharomyces cerevisiae, COS-7, and V79 cells, by comparison of Km values of the recombinant enzyme in cell extracts with enzyme present in human platelets and with recombinant enzyme purified to homogeneity following E. coli expression. This is the first report of heterologous expression of a cytosolic sulfotransferase in yeast. Expression of SULT1A3 was achieved in all cell types, and the Km for dopamine under the conditions applied was approximately 1 microM in all heterologous systems studied, which compared favorably with the value determined with human platelets. We also determined the subunit and native molecular weights of the purified recombinant enzyme by SDS-PAGE, electrospray ionization mass spectrometry, dynamic light scattering, and sedimentation analysis. The enzyme purified following expression in E. coli existed as a homodimer with Mr approximately 68,000 as determined by light scattering and sedimentation analysis. Mass spectrometry revealed two species with experimentally determined masses of 34,272 and 34,348 which correspond to the native protein with either one or two 2-mercaptoethanol adducts. We conclude that the enzyme expressed in prokaryotic and eukaryotic heterologous systems, and also purified from E. coli, equates to that which is found in human tissue preparations.

X-ray crystal structure of human dopamine sulfotransferase, SULT1A3. Molecular modeling and quantitative structure-activity relationship analysis demonstrate a molecular basis for sulfotransferase substrate specificity.

Humans are one of the few species that produce large amounts of catecholamine sulfates, and they have evolved a specific sulfotransferase, SULT1A3 (M-PST), to catalyze the formation of these conjugates. An orthologous protein has yet to be found in other species. To further our understanding of the molecular basis for the unique substrate selectivity of this enzyme, we have solved the crystal structure of human SULT1A3, complexed with 3'-phosphoadenosine 5'-phosphate (PAP), at 2.5 A resolution and carried out quantitative structure-activity relationship (QSAR) analysis with a series of phenols and catechols. SULT1A3 adopts a similar fold to mouse estrogen sulfotransferase, with a central five-stranded beta-sheet surrounded by alpha-helices. SULT1A3 is a dimer in solution but crystallized with a monomer in the asymmetric unit of the cell, although dimer interfaces were formed by interaction across crystallographic 2-fold axes. QSAR analysis revealed that the enzyme is highly selective for catechols, and catecholamines in particular, and that hydrogen bonding groups and lipophilicity (cLogD) strongly influenced K(m). We also investigated further the role of Glu(146) in SULT1A3 using site-directed mutagenesis and showed that it plays a key role not only in defining selectivity for dopamine but also in preventing many phenolic xenobiotics from binding to the enzyme.