Synergy between the genes for butyrylcholinesterase K variant and apolipoprotein E4 in late-onset confirmed Alzheimer's disease

The allelic frequency of the gene for the K variant of butyrylcholinesterase (BCHE-K) was 0.17 in 74 subjects with late-onset (age > 65 years) histopathologically diagnosed Alzheimer's disease (AD), which was higher than the frequencies in 104 elderly control subjects (0.09), in 14 early-onset cases of confirmed AD (0.07) and in 29 confirmed cases of other dementia (0.10). The association of BCHE-K with late-onset AD was limited to carriers of the epsilon 4 allele of the apolipoprotein E gene (APOE), among whom the presence of BCHE-K gave an odds ratio of confirmed late-onset AD of 6.9 (95% C.I. 1.65-29) in subjects > 65 years and of 12.8 (1.9-86) in subjects > 75 years. In APOE epsilon 4 carriers over 75 years, only 1/22 controls, compared with 10/24 confirmed late-onset AD cases, had BCHE-K. We suggest that BCHE-K, or a nearby gene on chromosome 3, acts in synergy with APOE epsilon 4 as a susceptibility gene for late-onset AD.      

ATRX encodes a novel member of the SNF2 family of proteins: mutations point to a common mechanism underlying the ATR-X syndrome

It was shown recently that mutations of the ATRX gene give rise to a severe, X-linked form of syndromal mental retardation associated with alpha thalassaemia (ATR-X syndrome). In this study, we have characterised the full-length cDNA and predicted structure of the ATRX protein. Comparative analysis shows that it is an entirely new member of the SNF2 subgroup of a superfamily of proteins with similar ATPase and helicase domains. ATRX probably acts as a regulator of gene expression. Definition of its genomic structure enabled us to identify four novel splicing defects by screening 52 affected individuals. Correlation between these and previously identified mutations with variations in the ATR-X phenotype provides insights into the pathophysiology of this disease and the normal role of the ATRX protein in vivo.      

Identification of non-amplifying CYP21 genes when using PCR-based diagnosis of 21-hydroxylase deficiency in congenital adrenal hyperplasia (CAH) affected pedigrees

Steroid 21-hydroxylase deficiency is among the most common inborn errors of metabolism in man. Characterization of mutations in the 21- hydroxylase gene (CYP21) has permitted genetic diagnosis, facilitated by the polymerase chain reaction (PCR). The most common mutation is conversion of an A or C at nt656 to a G in the second intron causing aberrant splicing of mRNA. Homozygosity for nt656G is associated with profoundly deficient adrenal cortisol and aldosterone synthesis, secondary hypersecretion of adrenal androgens, and a severe form of congenital adrenal hyperplasia (CAH) characterized by ambiguous genitalia and/or sodium wasting in newborns. During the course of genetic analysis of CYP21 mutations in CAH families, we and others have noticed a number of relatives genotyped as nt656G homozygotes, yet showing no clinical signs of disease. A number of lines of evidence have led us to propose that the putative asymptomatic nt656G/G individuals are incorrectly typed due to dropout of one haplotype during PCR amplification of CYP21. For prenatal diagnosis, we recommend that microsatellite typing be used as a supplement to CYP21 genotyping in order to resolve ambiguities at nt656.      

Regulatory Th2-type T cell Lines Against Insulin and GAD Peptides Derived from Orally- and Nasally-Treated NOD Mice Suppress Diabetes

Non-obese diabetic (NOD) mice spontaneously develop diabetes. Ourselves and others have previously shown that oral and nasal administration of insulin or glutamic acid decarboxylase (GAD) suppresses development of diabetes in the NOD mouse and that this suppression appears secondary to the generation of regulatory T cells that act by secreting anti-inflammatory cytokines such as IL-4 and TGF-beta. In the present study, we analysed cytokine patterns associated with mucosal administration of insulin B-chain, B-chain peptide 10-24 and GAD peptide 524-543 and derived lines and clones from mucosally-treated animals. Mice were fed five times (400-600 microg/feed) or nasally-treated three times (60 microg/application), and 2 days after the last treatment were immunized in the footpad with the mucosally administered antigen in CFA. Primary immune responses in the popliteal lymph node were measured 10 days after immunization and lines and clones were then established from the primary cultures. There was significantly less IFN-gamma production in mucosally-treated mice associated with increased production of IL-10 and TGF-beta. The nature of the antigen appeared to determine cytokine production as the B-chain given either orally or nasally primed for TGF-beta responses, whereas mucosally administered B-chain peptide 10-24 primed for IL-10. T cell clones, established from draining lymph nodes of fed or nasally-treated animals, secreted IL-4, IL-10 and TGF-beta whereas those from non-fed mice secreted IL-2 and IFN-gamma. Transfer of Th1 lines with splenocytes from diabetic NOD mice into NOD or NOD/SCID animals accelerated diabetes, whereas transfer of Th2 lines suppressed the development of diabetes. Our results further support a role for Th2-type cells in the regulation of diabetes in NOD mice.     

Qualitative analysis by interviews and video recordings to establish the components of a skilled low-cavity non-rotational vacuum delivery

Objectives  The objectives of this study were to define the components of a skilled low-cavity non-rotational vacuum delivery (occiput anterior, vertex at station +2 or below and less than 45-degree rotation from midline) and to facilitate the transfer of skills from expert to trainee obstetricians.
Design  Qualitative study using interviews and video recordings.
Setting  Two university teaching hospitals (St Michael's Hospital, Bristol, and Ninewell's Hospital, Dundee).
Participants  Ten obstetricians and eight midwives identified as experts in conducting or supporting operative vaginal deliveries.
Methods  Semi-structured interviews were carried out using routine clinical scenarios. The experts were also video recorded conducting low-cavity vacuum deliveries in a simulation setting. The interviews and video recordings were transcribed verbatim and analysed using thematic coding. The anonymised data were independently coded by three researchers and compared for consistency of interpretation. The experts reviewed the coded interviews and video data for respondent validation and clarification. The themes that emerged following the final coding were used to formulate a list of skills.
Main outcome measures  Key technical skills of a low-cavity non-rotational delivery.
Results  The final list included detailed technical skills required for conducting a low-cavity vacuum delivery. The combination of semi-structured interviews and simulation videos allowed the formulation of a comprehensive skills tool for future evaluation.
Conclusion  This explicitly defined skills list could aid trainees understanding of the technique of low-cavity vacuum delivery. This is an important first step in evaluating clinical competence in intrapartum procedures.