An analysis of fetal hemoglobin variation in sickle cell disease: the relative contributions of the X-linked factor, beta-globin haplotypes, alpha-globin gene number, gender, and age

Five factors have been shown to influence the 20-fold variation of fetal hemoglobin (Hb F) levels in sickle cell anemia (SS): age, sex, the alpha-globin gene number, beta-globin haplotypes, and an X-linked locus that regulates the production of Hb F-containing erythrocytes (F cells), ie, the F-cell production (FCP) locus. To determine the relative importance of these factors, we studied 257 Jamaican SS subjects from a Cohort group identified by newborn screening and from a Sib Pair study. Linear regression analyses showed that each variable, when analyzed alone, had a significant association with Hb F levels (P < .05). Multiple regression analysis, including all variables, showed that the FCP locus is the strongest predictor, accounting for 40% of Hb F variation. beta-Globin haplotypes, alpha-globin genes, and age accounted for less than 10% of the variation. The association between the beta-globin haplotypes and Hb F levels becomes apparent if the influence of the FCP locus is removed by analyzing only individuals with the same FCP phenotype. Thus, the FCP locus is the most important factor identified to date in determining Hb F levels. The variation within each FCP phenotype is modulated by factors associated with the three common beta-globin haplotypes and other as yet unidentified factor(s).     

Can sensitization to aeroallergens disappear over time in children with allergic disease?

Background: Remittance of aeroallergen sensitization has been shown in population‐based studies, but there is a common perception that sensitization to aeroallergens rarely if ever disappears in children with allergic disease. Methods: We retrospectively reviewed all specific IgE tests carried out in children aged 0–18 years at our hospital laboratory over a 14‐year period. Of 3115 children sensitized to one or more aeroallergens, 244 (7.8%) were retested after a mean (SD) period of 45 (28) months at their physician’s discretion. Results: Disappearance of sensitization to individual aeroallergens did occur, with remittance rates ranging from 3.1% for house dust mite to 17.5% for cat. However, complete remittance of aeroallergen sensitization was found in only one subject. In up to 35% of cases, remittance of sensitization was offset by the appearance of one or more new aeroallergen sensitizations. Remittance was only observed in children sensitized to multiple allergens (with a median of 3 aeroallergen sensitizations), and their median degree of sensitization was low (median 2.1 kU/L). Conclusion: Aeroallergen sensitization can disappear in children with allergic disease, but only in polysensitized individuals. Complete remittance of sensitization to aeroallergens is rare in symptomatic children.     

NADH-dependent prostaglandin E2-9-ketoreductase activity and prostaglandin synthesis in the Brattleboro rat kidney: effects of the antidiuretic hormone

The activity of prostaglandin (PG)E2-9-ketoreductase (9KR), an enzyme catalyzing the conversion of PGE2 to PGF2 alpha, was significantly increased in glomerular and cortical homogenates of diabetes insipidus (DI) rats, as compared to normal Long Evans (LE) rats, and did not change with ADH treatment. Medullary 9KR was similar in the three groups and papillary 9KR was increased, but not significantly, in both groups of DI rats. Km values for PGE2 and NADH were compared in the various compartments of the kidney. Levels of 9KR were not correlated with the PGE/PGF ratio in urine or supernatants. The synthesis of PGE2 and PGF2 alpha by isolated glomeruli was increased in DI rats. This was not reversed by ADH treatment, PGE2 synthesis increasing even further, especially in the presence of arachidonic acid. In contrast, medullary slices produced significantly less PGs in DI than in LE rats and returned to normal with ADH treatment. Papillary slices produced similar quantities of prostaglandins in all groups. The results do not support the concept that the alterations in PG synthesis observed in DI rat are related only to changes in 9KR activity, but do not exclude the possibility that the enzyme participates in the regulation of PG biosynthesis.     

Phylogeny and Disease Association of Shiga Toxin�Cproducing Escherichia coli O91

The diversity and relatedness of 100 Shiga toxin–producing Escherichia coli O91 isolates from different patients were examined by multilocus sequence typing. We identified 10 specific sequence types (ST) and 4 distinct clonal groups. ST442 was significantly associated with hemolytic uremic syndrome.     

颠茄类生物碱的毛细管气相色谱和色—质联用分析

本文用毛细管气相色谱和气相色谱-质量选择检测器分析颠茄生物碱类(莨菪碱、东莨菪碱、山莨菪碱和樟柳碱)的研究。对颠茄生物碱与不同硅烷化试剂、反应能力、反应时间以及反应温度作了探索。结果表明,MSTFA是最好的硅烷化试剂。文内给出了这些生物碱的原型和硅烷化衍生物的保留值和它们的特征性碎片离子。这些数据有助于该类生物碱的鉴定。方法已初步应用于这些生物碱在生物合成中的转化研究。此外,还讨论了颠茄生物碱类TMS衍生化的优点。     

Shiga toxin-producing Escherichia coli serogroups in food and patients, Germany

We compared 61 Shiga toxin-producing Escherichia coli (STEC) serogroups from 448 food isolates with 71 STEC serogroups from 1,447 isolates from patients in Germany. Two thirds (41/61), representing 72% of food isolates, were also found in patients. Serogroups typically isolated from patients with hemolytic uremic syndrome were rarely found in food.