Hemophilia A: carrier detection and prenatal diagnosis by DNA analysis

In this study, we used DNA polymorphisms for carrier detection and prenatal diagnosis of hemophilia A in a large group of Italian families. The restriction fragment length polymorphisms (RFLPs) investigated were the intragenic polymorphic Bc/I site within the factor VIII gene; the extragenic multiallelic Taq I system at the St14 locus; and the extragenic Bg/II site at the DX13 locus. The factor VIII probe was informative in 30%, St14 in 82%, and DX13 in 60% of obligate carriers. The combination of factor VIII-Bc/I and St14-Taq I showed that 91% of obligate carriers were heterozygotes for one or both; with all three probes, only 4% of obligate carriers were noninformative. In families clearly segregating for hemophilia A, RFLP analysis allowed us to define the carrier status for the hemophilia A gene in all 27 women tested. RFLP analysis allowed us to exclude the carrier status in 39 of 45 female relatives of sporadic patients. The combination of RFLP analysis and biological assay of factor VIII allowed us to identify a de novo mutation in the maternal grandfather in 7 of 12 of the families with sporadic cases, for which members of three generations were available for study. Nine of 10 couples requesting prenatal diagnosis provided informative RFLP DNA pattern. Carrier status was excluded in two women, two fetuses were shown to be female, and prenatal diagnosis was carried out in five pregnancies by DNA analysis. Prenatal testing was successful in three instances and failed in two because a sufficient amount of chorionic villous DNA was not obtained for the analysis.     

Hereditary nonspherocytic hemolytic anemia and hexokinase deficiency

An 11-yr-old child with mild chronic hemolytic anemia was found to have decreased red cell hexokinase activity in spite of the reduced mean age of her red cell population. Similar decreases in red cell hexokinase activity were documented in the patient's parents and in one sib. The red cells were morphologically normal. Red cell 2,3-DPG levels were normal and ATP and glucose-6-phosphate levels were diminished. The kinetic properties, electrophoretic mobility, and thermal stability of the residual red cell hexokinase were normal or nearly so. Glucose consumption of the hexokinase-deficient cells was not appreciably decreased, probably because less of the potent inhibitor glucose-6- phosphate was present in the erythrocytes. It is likely, although not certain, that in this patient nonspherocytic hemolytic anemia resulted from hexokinase deficiency.     

Interatrial and sinoatrial block,with an illustrative case

Sinoatrial block of two types has been described; (1) with progressive prolongation of sinoatrial conduction time leading to a dropped beat; and (2) dropped beats without such preceding conduction changes. These are strictly analogous to the Wenckebach and the Mobitz types of atrioventricular block. The literature on this subject has been surveyed, together with available information on the postulated anatomic and functional pathways of inter- and intra-atrial conduction.We have postulated that, in the present case, both varieties of sinoatrial block coexist, thus explaining the variable distance between the two types of P waves. Such a hypothesis also requires the assumption of functional pathways between the S-A node and the two atria, with dissociation of the two atria, and with partial dissimilar block between each atrium and the S-A node. Although interatrial dissociation, both partial and complete, and each variety of sinoatrial block have been previously described, so far as we have been able to learn, their coexistence has not been previously noted.     

Possible relationships between changes in body weight set-point and stress metabolism after treating rats chronically with D-fenfluramine. Effects of feeding rats acutely with fructose on the metabolism of corticosterone, glucose, fatty acids, glycerol and triacylglycerol

Rats were maintained on a corn oil diet and treated with D-fenfluramine at doses of 2.5 mg/kg twice a day for 11 days or with 10 mg or 25 mg/kg once a day for 12 days. The lower dose of D-fenfluramine produced no marked changes in body weight and after 11 days of treatment the weights of the rats on average were only 2% lower than the controls. The food intake of these rats was only decreased on the first day. The two higher doses of D-fenfluramine decreased the food consumption for about 3 days but thereafter it was similar to that of the control rats. The body weight of these rats fell on the first day, but after about four days the gain in body weight paralleled rather than approached that of the control rats. Increasing the dose of D-fenfluramine progressively decreased the relative size of the epididymal fat pad. At the end of the treatment period the rats were fed acutely with fructose to increase the circulating concentrations of corticosterone and to stimulate triacylglycerol synthesis. All three doses of D-fenfluramine decreased the concentration of circulating triacylglycerol after fructose feeding. The 10 mg/kg dose also decreased the basal concentration of triacylglycerol. The two higher doses of fenfluramine decreased the rises in the circulating concentrations of corticosterone, glycerol and fatty acids that are produced by fructose feeding. The basal concentrations of these compounds in the absence of fructose feeding were not significantly affected by the 10 mg/kg dose of D-fenfluramine. The possible relationship between the effect of chronic treatment with D-fenfluramine in decreasing a metabolic stress response and lipolysis is discussed relative to its hypotriglyceridaemic action and its effect on body weight-set point. The results demonstrate that D-fenfluramine produced persistent changes in metabolism at a time when the treated rats were growing at the same rate as the control rats and when they were eating similar quantities of food.     

Role of transforming growth factor beta in peritoneal fibrosis

SUMMARY: Technique survival of peritoneal dialysis is seriously limited by the development of peritoneal fibrosis. the mesothelial cell layer lining the peritoneum is important in the pathogenesis of peritoneal fibrosis. Mesothelial cells are able to produce transforming growth factor beta (TGF-β), and respond to stimulation by this cytokine. In this review, we will detail the evidence available so far for the role of the complex interaction between TGF-β and mesothelial cells in the development of peritoneal fibrosis.     

Tandemly repeated genomic sequence demonstrates inter- and intra-strain genetic variation in Schistosoma japonicum*

Genetic variability within and among four geographical strains of Schistosoma japonicum was examined using a novel repetitive element. The element, termed Sjrh1.0, was isolated from genomic DNA of a Philippine strain of S. japonicum using a combination of restriction fragment PCR and band-stab PCR. Sjrh1.0 is a tandemly repeated element, the sequence of which appears to be species-specific, in that it hybridized to DNA from S. japonicum but not to DNA from S. mansoni . Its sequence does not match previously deposited sequences in GenBank. When employed as a probe in Southern hybridization analysis, radiolabelled Sjrh1.0 revealed sex-specific and strain-specific differences in genomic DNA of individual worms. We also found individual genetic variation within geographical isolates of the Asian schistosome.     

Polystyrene-Poly (Ethylene Glycol) (PS-PEG2000) Particles as Model Systems for Site Specific Drug Delivery. 2. The Effect of PEG Surface Density on the in Vitro Cell Interaction and in VivoBiodistribution

The effect of differing densities of poly (ethylene glycol-2000) (PEG2000) at the particle surface of polystyrene-poly (ethylene glycol-2000) (PS-PEG2000) particles was assessed in terms of hydrophobic interaction chromatography (HIC) and the in vitro and in vivo behaviour of the particles. The particles, with different surface densities of PEG, were prepared by varying the copolymerizing reaction of styrene with a PEG macromonomer. There is a clear relationship between the surface density of PEG as determined by X-ray photoelectron spectroscopy and surface hydrophobicity as assessed by hydrophobic interaction chromatography (HIC). Similarly, the interaction of the particles with non-parenchymal liver cells in in vitro studies was shown to decrease as the surface density of PEG increases. The in vivo study investigating the biodistribution of the PS-PEG particles after intravenous injection into rats reveals that a relationship exists between the surface density of PEG and the extent to which the particles remain in the circulation, avoiding recognition by the reticuloendothelial system. Particles with the higher surface densities show increased circulatory times which compared well with data for particles prepared with the surface adsorbed PEO-PPO block copolymer, Poloxamine 908.