Genome-wide linkage of obstructive sleep apnoea and high-density lipoprotein cholesterol in a Filipino family: bivariate linkage analysis of obstructive sleep apnoea.

Increasing evidence supports an association between obstructive sleep apnoea (OSA) and metabolic syndrome (MeS) in both children and adults, suggesting a genetic component. However, the genetic relationship between the diseases remains unclear. We performed a bivariate linkage scan on a single Filipino family with a high prevalence of OSA and MeS to explore the genetic pathways underlying these diseases. A large rural family (n = 50, 50% adults) underwent a 10-cM genome-wide scan. Fasting blood was used to measure insulin, triglycerides, total cholesterol and high density lipoprotein (HDL) cholesterol. Attended overnight polysomnography was used to quantify the respiratory disturbance index (RDI), a measure of sleep apnoea. Body mass index z-scores and insulin resistance scores were calculated. Bivariate multipoint linkage analyses were performed on RDI and MeS components. OSA prevalence was 46% (n = 23; nine adults, 14 children) in our participants. MeS phenotype was present in 40% of adults (n = 10) and 48% of children (n = 12). Linkage peaks with a logarithm of odds (LOD) score >3 were demonstrated on chromosome 19q13.4 (LOD = 3.04) for the trait pair RDI and HDL cholesterol. Candidate genes identified in this region include the killer cell immunoglobulin-like receptor genes. These genes are associated with modulating inflammatory responses in reaction to cellular stress and initiation of atherosclerotic plaque formation. We have identified a novel locus for genetic links between RDI and lipid factors associated with MeS in a chromosomal region containing genes associated with inflammatory responses.

Retrieval of mRNA from paraffin-embedded human infant brain tissue for non-radioactive in situ hybridization using oligonucleotides.

In situ hybridization (ISH) is used to examine the spatiotemporal distribution of gene expression in a range of tissues. Neuroscience research in human brain tissue requires techniques that can be used in formalin fixed and paraffin-embedded tissue rather than frozen tissue which is recommended, but difficult to obtain. This study presents a method for non-radioactive (DIG) ISH for detecting NR1 gene expression, in human infant brain tissue. We compared three pre-treatment effects, protease digestion, autoclaving (in citrate and Tris/EDTA buffer) and microwaving (in citrate and Tris/EDTA buffer). Tissue had been fixed in formalin for 2-12 weeks. Results were compared for the hybridization and background signal intensities, and tissue morphology. We found that optimum results were obtained using 12-min microwave pre-treatment in Tris/EDTA buffer. This method produced optimum signal to background ratio in infant and adult tissue, preserved tissue morphology, and was suitable for use across a broad range of fixation times.

Engrailed is expressed in larval development and in the radial nervous system of Patiriella sea stars.

We documented expression of the pan-metazoan neurogenic gene engrailed in larval and juvenile Patiriella sea stars to determine if this gene patterns bilateral and radial echinoderm nervous systems. Engrailed homologues, containing conserved En protein domains, were cloned from the radial nerve cord. During development, engrailed was expressed in ectodermal (nervous system) and mesodermal (coeloms) derivatives. In larvae, engrailed was expressed in cells lining the larval and future adult coeloms. Engrailed was not expressed in the larval nervous system. As adult-specific developmental programs were switched on during metamorphosis, engrailed was expressed in the central nervous system and peripheral nervous system (PNS), paralleling the pattern of neuropeptide immunolocalisation. Engrailed was first seen in the developing nerve ring and appeared to be up-regulated as the nervous system developed. Expression of engrailed in the nerve plexus of the tube feet, the lobes of the hydrocoel along the adult arm axis, is similar to the reiterated pattern of expression seen in other animals. Engrailed expression in developing nervous tissue reflects its conserved role in neurogenesis, but its broad expression in the adult nervous system of Patiriella differs from the localised expression seen in other bilaterians. The role of engrailed in patterning repeated PNS structures indicates that it may be important in patterning the fivefold organisation of the ambulacrae, a defining feature of the Echinodermata.