Atopic dermatitis, educational attainment and psychological functioning: a national cohort study.

BACKGROUND: Atopic dermatitis (AD) might adversely affect academic performance, possibly through influences on psychological functioning such as stress resilience. OBJECTIVES: To investigate the association of atopic dermatitis with stress resilience, cognitive function and educational attainment. METHODS: We used data from a national cohort of men who underwent a military conscription examination at ages 17-20 years in Sweden between 1969 and 1976. All potential conscripts met a physician who assessed current or previous history of AD. Stress resilience was measured by a psychologist using a semistructured interview. The conscription assessment included a written cognitive function test. The highest level of education achieved was identified through record linkage. RESULTS: The study population included 234 715 men, 1673 (0·7%) of whom had a diagnosis of AD. AD was associated with a greater risk of low stress resilience [adjusted relative risk ratio (RRR) 1·60, 95% confidence interval (CI) 1·38-1·86]. AD was associated with higher cognitive function (ß-coefficient 0·15, 95% CI 0·05-0·24) and higher educational level (RRR 1·29, 95% CI 1·13-1·47). However, adjustment for socioeconomic characteristics of the family of origin attenuated the magnitude of the associations and eliminated the statistical significance (ß-coefficient 0·06, 95% CI -0·03 to 0·15; RRR 1·16, 95% CI 1·00-1·35). CONCLUSIONS: Swedish men with AD had lower stress resilience in late adolescence but did not have lower cognitive function or poorer educational attainment. The lower stress resilience associated with AD is consistent with an increased risk of possible long-term adverse health outcomes.

Genetic polymorphism of the human tumor necrosis factor region in insulin-dependent diabetes mellitus. Linkage disequilibrium of TNFab microsatellite alleles with HLA haplotypes.

The TNF region within the MHC includes a number of immunologically important genes. Microsatellites TNFa and TNFb adjacent to TNF exhibit extensive polymorphism. Employing a PCR-based technique, we identified TNFab haplotypes and defined their distribution in 97 controls and 48 diabetics of Caucasoid origin in a search for other genes within the MHC potentially associated with IDDM. Twenty-five different TNFab haplotypes were identified. A significant difference (p < 0.0005) in frequency between patients and controls was found for TNFa1b5 (relative risk 53). However, no other TNFab microsatellites demonstrated significantly different frequencies. Among diabetics TNFa1b5 was found to be in linkage disequilibrium with HLA-DR3-B18, a haplotype known to be associated with IDDM. Thus the increased frequency of TNFa1b5 among diabetics could reflect a linkage disequilibrium with a gene within the TNF region or with other genes, including the HLAs, which characterize this haplotype. In both controls and diabetics TNFa2b3 and TNFa7b4 were in linkage disequilibrium with DR3-B8 and DR7, respectively. Among diabetics, TNFa2b1 and TNFa6b5 were in linkage disequilibrium with DR4-B62 and DR4-B44, respectively. It is intriguing that TNFab haplotypes, represented by a short piece of about 200 nucleotides in the untranslated region upstream of TNF beta gene, maintain strong linkage disequilibria with different HLA haplotypes extending over 1 million base pairs. The identification of TNFab microsatellites exhibiting a high polymorphic index in a region lacking known polymorphic markers may provide potentially important information regarding the association of HLA haplotypes with autoimmune diseases, as they are in close proximity to other genes of immunologic importance.

Effects of calcium ions on electrical responses of gastric gland cells to histamine and pentagastrin.

The effect of Ca ions on electrical responses of gastric gland cells on histamine and pentagastrin was investigated using intracellular glass microelectrodes. It was established that in low-calcium solutions hyperpolarization induced by these secretagogues was diminished. In calcium-free solutions and in solutions with blockers of the calcium current hyperpolarization induced by histamine and pentagastrin was not observed. It was suggested that external calcium ions are necessary for hyperpolarization responses to histamine and pentagastrin actions on gastric gland cells to occur.

Two variants of the Drosophila melanogaster retrotransposon gypsy (mdg4): structural and functional differences, and distribution in fly stocks.

Two variants of the Drosophila melanogaster retrotransposon gypsy were subjected to detailed structural and functional analysis. A series of hybrid constructs containing various combinations of "active" and "inactive" gypsy copies were tested for their ability to produce new DNA copies in cultured cells by means of reverse transcription. It was shown that the previously demonstrated variations in retrotranspositional activity are associated with either one or both of two amino acid substitutions at the beginning of ORF2. The first substitution is located at the boundary between the putative protease and reverse transcriptase domains and, hence, may influence the processing of the polyprotein. The other substitution may alter reverse transcriptase activity since it is located in the second of the seven conserved domains of the RT gene. To address the question of the evolutionary relationship between the two gypsy variants, their distribution was analyzed in among various fly stocks. Southern analysis revealed that all D. melanogaster strains studied so far contain the "inactive" gypsy variant, while the "active" copies are present only in some strains; most of the latter were established from flies recently isolated from natural populations. Finally, in stocks carrying the flamenco mutation the "active" gypsy variant is much more abundant than the "inactive" form. Possible scenarios for the orgin of the "active" form of gypsy are discussed.