Gene expression studies in multiple sclerosis

Multiple sclerosis (MS) is a serious neurological disorder affecting young Caucasian individuals, usually with an age of onset at 18 to 40 years old. Females account for approximately 60x of MS cases and the manifestation and course of the disease is highly variable from patient to patient. The disorder is characterised by the development of plaques within the central nervous system (CNS). Many gene expression studies have been undertaken to look at the specific patterns of gene transcript levels in MS. Human tissues and experimental mice were used in these gene-profiling studies and a very valuable and interesting set of data has resulted from these various expression studies. In general, genes showing variable expression include mainly immunological and inflammatory genes, stress and antioxidant genes, as well as metabolic and central nervous system markers. Of particular interest are a number of genes localised to susceptible loci previously shown to be in linkage with MS. However due to the clinical complexity of the disease, the heterogeneity of the tissues used in expression studies, as well as the variable DNA chips/membranes used for the gene profiling, it is difficult to interpret the available information. Although this information is essential for the understanding of the pathogenesis of MS, it is difficult to decipher and define the gene pathways involved in the disorder. Experiments in gene expression profiling in MS have been numerous and lists of candidates are now available for analysis. Researchers have investigated gene expression in peripheral mononuclear white blood cells (PBMCs), in MS animal models Experimental Allergic Encephalomyelitis (EAE) and post mortem MS brain tissues. This review will focus on the results of these studies.

A pharmacogenomic evaluation of migraine therapy

Migraine is a common idiopathic primary headache disorder with significant mental, physical and social health implications. Accompanying an intense unilateral pulsating head pain other characteristic migraine symptoms include nausea, emesis, phonophobia, photophobia and in approximately 20-30% of migraine cases, neurologic disturbances associated with the aura phase. Although selective serotonin (5-HT) receptor agonists (i.e., 5-HT(1B/1D)) are successful in alleviating migrainous symptoms in < or = 70% of known sufferers, for the remaining 30%, additional migraine abortive medications remain unsuccessful, not tested or yet to be identified. Genetic characterization of the migrainous disorder is making steady progress with an increasing number of genomic susceptibility loci now identified on chromosomes 1q, 4q, 5q, 6p, 11q, 14q, 15q, 17p, 18q, 19p and Xq. The 4q, 5q, 17p and 18q loci involve endophenotypic susceptibility regions for various migrainous symptoms. In an effort to develop individualized pharmacotherapeutics, the identification of these migraine endophenotypic loci may well be the catalyst needed to aid in this goal. In this review the authors discuss the present treatment of migraine, known genomic susceptibility regions and results from migraine (genetic) association studies. The authors also discuss pharmacogenomic considerations for more individualized migraine prophylactic treatments.

Multi-gene phylogenetic analysis of south-east Asian pest members of the Bactrocera dorsalis species complex (Diptera: Tephritidae) does not support current taxonomy

Bactrocera dorsalis sensu stricto, B. papayae, B. philippinensis and B. carambolae are serious pest fruit fly species of the B. dorsalis complex that predominantly occur in south-east Asia and the Pacific. Identifying molecular diagnostics has proven problematic for these four taxa, a situation that cofounds biosecurity and quarantine efforts and which may be the result of at least some of these taxa representing the same biological species. We therefore conducted a phylogenetic study of these four species (and closely related outgroup taxa) based on the individuals collected from a wide geographic range; sequencing six loci (cox1, nad4-3′, CAD, period, ITS1, ITS2) for approximately 20 individuals from each of 16 sample sites. Data were analysed within maximum likelihood and Bayesian phylogenetic frameworks for individual loci and concatenated data sets for which we applied multiple monophyly and species delimitation tests. Species monophyly was measured by clade support, posterior probability or bootstrap resampling for Bayesian and likelihood analyses respectively, Rosenberg's reciprocal monophyly measure, P(AB), Rodrigo's (P(RD)) and the genealogical sorting index, gsi. We specifically tested whether there was phylogenetic support for the four 'ingroup' pest species using a data set of multiple individuals sampled from a number of populations. Based on our combined data set, Bactrocera carambolae emerges as a distinct monophyletic clade, whereas B. dorsalis s.s., B. papayae and B. philippinensis are unresolved. These data add to the growing body of evidence that B. dorsalis s.s., B. papayae and B. philippinensis are the same biological species, which poses consequences for quarantine, trade and pest management.

Phenotypical characterisation of the isolated Norfolk Island population focusing on epidemiological indicators of cardiovascular disease

Objectives Only 193 people from Pitcairn Island, all descended from 9 ‘Bounty’ mutineers and 12 Tahitian women, moved to the uninhabited Norfolk Island in 1856. Our objective was to assess the population of Norfolk Island, several thousand km off the eastern coast of Australia, as a genetic isolate of potential use for cardiovascular disease (CVD) gene mapping. Methods A total of 602 participants, approximately two thirds of the island’s present adult population, were characterized for a panel of CVD risk factors. Statistical power and heritability were calculated. Results Norfolk Islander’s possess an increased prevalence of hypertension, obesity and multiple CVD risk factors when compared to outbred Caucasian populations. 64% of the study participants were descendents of the island’s original founder population. Triglycerides, cholesterol, and blood pressures all had heritabilities above 0.2. Conclusions The Norfolk land population is a potentially useful genetic isolate for gene mapping studies aimed at identifying CVD risk factor quantitative trait loci (QTL).

Association of the NuMA region on chromosome 11q13 with breast cancer susceptibility

The development of breast cancer is a complex process that involves multiple genes at many stages, from initial cell cycle dysregulation to disease progression. To identify genetic variations that influence this process, we conducted a large-scale association study using a collection of German cases and controls and >25,000 SNPs located within 16,000 genes. One of the loci identified was located on chromosome 11q13 [odds ratio (OR)=1.85, P=0.017]. The initial association was subsequently tested in two independent breast cancer collections. In both sample sets, the frequency of the susceptibility allele was increased in the cases (OR=1.6, P=0.01). The susceptibility allele was also associated with an increase in cancer family history (P=0.1). Fine mapping showed that the region of association extends approximately 300 kb and spans several genes, including the gene encoding the nuclear mitotic apparatus protein (NuMA). A nonsynonymous SNP (A794G) in NuMA was identified that showed a stronger association with breast cancer risk than the initial marker SNP (OR=2.8, P=0.005 initial sample; OR=2.1, P=0.002 combined). NuMA is a cell cycle-related protein essential for normal mitosis that is degraded in early apoptosis. NuMA-retinoic acid receptor alpha fusion proteins have been described in acute promyelocytic leukemia. Although the potential functional relevance of the A794G variation requires further biological validation, we conclude that variations in the NuMA gene are likely responsible for the observed increased breast cancer risk.

Genetic polymorphisms in DPF3 associated with risk of breast cancer and lymph node metastases

Background Several studies have identified rare genetic variations responsible for many cases of familial breast cancer but their contribution to total breast cancer incidence is relatively small. More common genetic variations with low penetrance have been postulated to account for a higher proportion of the population risk of breast cancer. Methods and Results In an effort to identify genes that influence non-familial breast cancer risk, we tested over 25,000 single nucleotide polymorphisms (SNPs) located within approximately 14,000 genes in a large-scale case-control study in 254 German women with breast cancer and 268 age-matched women without malignant disease. We identified a marker on chromosome 14q24.3-q31.1 that was marginally associated with breast cancer status (OR = 1.5, P = 0.07). Genotypes for this SNP were also significantly associated with indicators of breast cancer severity, including presence of lymph node metastases ( P = 0.006) and earlier age of onset ( P = 0.01). The association with breast cancer status was replicated in two independent samples (OR = 1.35, P = 0.05). High-density association fine mapping showed that the association spanned about 80 kb of the zinc-finger gene DPF3 (also known as CERD4 ). One SNP in intron 1 was found to be more strongly associated with breast cancer status in all three sample collections (OR = 1.6, P = 0.003) as well as with increased lymph node metastases ( P = 0.01) and tumor size ( P = 0.01). Conclusion Polymorphisms in the 5' region of DPF3 were associated with increased risk of breast cancer development, lymph node metastases, age of onset, and tumor size in women of European ancestry. This large-scale association study suggests that genetic variation in DPF3 contributes to breast cancer susceptibility and severity.

A typical migraine susceptibility region localizes to chromosome 1q31

Migraine (with and without aura) is a prevalent neurovascular disease that shows strong familial aggregation, although the number of genes involved and the mode of inheritance is not clear. Some insight into the disease has been gained from genetic studies into a rare and very severe migraine subtype known as familial hemiplegic migraine (FHM). In this study, we took a family-based linkage and association approach to investigate the FHM susceptibility region on chromosome 1q31 for involvement in typical migraine susceptibility in affected Australian pedigrees. Initial multipoint ALLEGRO analysis provided strong evidence for linkage of Chrlq31 markers to typical migraine in a large multigenerational pedigree. The 1-LOD* unit support interval for suggestive linkage spanned approximately 18 cM with a maximum allele sharing LOD* score of 3.36 obtained for marker D1S2782 (P=0.00004). Subsequent analysis of an independent sample of 82 affected pedigrees added support to the initial findings with a maximum LOD* of 1.24 (P=0.008). Utilising the independent sample of 82 pedigrees, we also performed a family-based association test. Results of this analysis indicated distortion of allele transmission at marker D1S249 [global chi2 (5) of 15.00, P=0.010] in these pedigrees. These positive linkage and association results will need further confirmation by independent researchers. However, overall they provide good evidence for the existence of a typical migraine locus near these markers on Chrlq3l, and reinforce the idea that an FHM gene in this genomic region may also contribute to susceptibility to the more common forms of migraine.

Dopamine receptor genes and migraine with and without aura : an association study

OBJECTIVE: To investigate the role of the dopamine receptor genes, DRD1, DRD3, and DRD5 in the pathogenesis of migraine. BACKGROUND: Migraine is a chronic debilitating disorder affecting approximately 12% of the white population. The disease shows strong familial aggregation and presumably has a genetic basis, but at present, the type and number of genes involved is unclear. The study of candidate genes can prove useful in the identification of genes involved in complex diseases such as migraine, especially if the contribution of the gene to phenotypic expression is minor. Genes coding for proteins involved in dopamine metabolism have been implicated in a number of neurologic conditions and may play a contributory role in migraine. Hence, genes that code for enzymes and receptors modulating dopaminergic activity are good candidates for investigation of the molecular genetic basis of migraine. METHODS: We tested 275 migraineurs and 275 age- and sex-matched individuals free of migraine. Genotypic results were determined by restriction endonuclease digestion of polymerase chain reaction products to detect DRD1 and DRD3 alleles and by Genescan analysis after polymerase chain reaction using fluorescently labelled oligonucleotide primers for the DRD5 marker. RESULTS: Results of chi-square statistical analyses indicated that the allele distribution for migraine cases compared to controls was not significantly different for any of the three tested gene markers (chi2 = 0.1, P =.74 for DRD1; chi2 = 1.8, P =.18 for DRD3; and chi2 = 20.3, P =.08 for DRD5). CONCLUSIONS: These findings offer no evidence for allelic association between the tested dopamine receptor gene polymorphisms and the more prevalent forms of migraine and, therefore, do not support a role for these genes in the pathogenesis of the disorder.

Clinically-indicated replacement versus routine replacement of peripheral venous catheters

BACKGROUND: US Centers for Disease Control guidelines recommend replacement of peripheral intravenous (IV) catheters no more frequently than every 72 to 96 hours. Routine replacement is thought to reduce the risk of phlebitis and bloodstream infection. Catheter insertion is an unpleasant experience for patients and replacement may be unnecessary if the catheter remains functional and there are no signs of inflammation. Costs associated with routine replacement may be considerable. This is an update of a review first published in 2010. OBJECTIVES: To assess the effects of removing peripheral IV catheters when clinically indicated compared with removing and re-siting the catheter routinely. SEARCH METHODS: For this update the Cochrane Peripheral Vascular Diseases (PVD) Group Trials Search Co-ordinator searched the PVD Specialised Register (December 2012) and CENTRAL (2012, Issue 11). We also searched MEDLINE (last searched October 2012) and clinical trials registries. SELECTION CRITERIA: Randomised controlled trials that compared routine removal of peripheral IV catheters with removal only when clinically indicated in hospitalised or community dwelling patients receiving continuous or intermittent infusions. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data. MAIN RESULTS: Seven trials with a total of 4895 patients were included in the review. Catheter-related bloodstream infection (CRBSI) was assessed in five trials (4806 patients). There was no significant between group difference in the CRBSI rate (clinically-indicated 1/2365; routine change 2/2441). The risk ratio (RR) was 0.61 but the confidence interval (CI) was wide, creating uncertainty around the estimate (95% CI 0.08 to 4.68; P = 0.64). No difference in phlebitis rates was found whether catheters were changed according to clinical indications or routinely (clinically-indicated 186/2365; 3-day change 166/2441; RR 1.14, 95% CI 0.93 to 1.39). This result was unaffected by whether infusion through the catheter was continuous or intermittent. We also analysed the data by number of device days and again no differences between groups were observed (RR 1.03, 95% CI 0.84 to 1.27; P = 0.75). One trial assessed all-cause bloodstream infection. There was no difference in this outcome between the two groups (clinically-indicated 4/1593 (0.02%); routine change 9/1690 (0.05%); P = 0.21). Cannulation costs were lower by approximately AUD 7.00 in the clinically-indicated group (mean difference (MD) -6.96, 95% CI -9.05 to -4.86; P ≤ 0.00001). AUTHORS' CONCLUSIONS: The review found no evidence to support changing catheters every 72 to 96 hours. Consequently, healthcare organisations may consider changing to a policy whereby catheters are changed only if clinically indicated. This would provide significant cost savings and would spare patients the unnecessary pain of routine re-sites in the absence of clinical indications. To minimise peripheral catheter-related complications, the insertion site should be inspected at each shift change and the catheter removed if signs of inflammation, infiltration, or blockage are present. OBJECTIVES: To assess the effects of removing peripheral IV catheters when clinically indicated compared with removing and re-siting the catheter routinely. SEARCH METHODS: For this update the Cochrane Peripheral Vascular Diseases (PVD) Group Trials Search Co-ordinator searched the PVD Specialised Register (December 2012) and CENTRAL (2012, Issue 11). We also searched MEDLINE (last searched October 2012) and clinical trials registries. SELECTION CRITERIA: Randomised controlled trials that compared routine removal of peripheral IV catheters with removal only when clinically indicated in hospitalised or community dwelling patients receiving continuous or intermittent infusions. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data. MAIN RESULTS: Seven trials with a total of 4895 patients were included in the review. Catheter-related bloodstream infection (CRBSI) was assessed in five trials (4806 patients). There was no significant between group difference in the CRBSI rate (clinically-indicated 1/2365; routine change 2/2441). The risk ratio (RR) was 0.61 but the confidence interval (CI) was wide, creating uncertainty around the estimate (95% CI 0.08 to 4.68; P = 0.64). No difference in phlebitis rates was found whether catheters were changed according to clinical indications or routinely (clinically-indicated 186/2365; 3-day change 166/2441; RR 1.14, 95% CI 0.93 to 1.39). This result was unaffected by whether infusion through the catheter was continuous or intermittent. We also analysed the data by number of device days and again no differences between groups were observed (RR 1.03, 95% CI 0.84 to 1.27; P = 0.75). One trial assessed all-cause bloodstream infection. There was no difference in this outcome between the two groups (clinically-indicated 4/1593 (0.02%); routine change 9/1690 (0.05%); P = 0.21). Cannulation costs were lower by approximately AUD 7.00 in the clinically-indicated group (mean difference (MD) -6.96, 95% CI -9.05 to -4.86; P ≤ 0.00001). AUTHORS' CONCLUSIONS: The review found no evidence to support changing catheters every 72 to 96 hours. Consequently, healthcare organisations may consider changing to a policy whereby catheters are changed only if clinically indicated. This would provide significant cost savings and would spare patients the unnecessary pain of routine re-sites in the absence of clinical indications. To minimise peripheral catheter-related complications, the insertion site should be inspected at each shift change and the catheter removed if signs of inflammation, infiltration, or blockage are present.

The GSTM1 null genotype confers an increased risk for Solar Keratosis Development in an Australian Caucasian Population

Solar keratoses affect approximately 50% of Australian Caucasians aged over 40 y. Solar keratoses can undergo malignant transformation into squamous cell carcinoma followed by possible metastasis and are risk factors for basal cell carcinoma, melanoma, and squamous cell carcinoma. The glutathione-S-transferase genes play a part in detoxification of carcinogens and mutagens, including some produced by ultraviolet radiation. This study examined the role of glutathione-S-transferase M1, T1, P1, and Z1 gene polymorphisms in susceptibility to solar keratoses development. Using DNA samples from volunteers involved in the Nambour Skin Cancer Prevention Trial, allele and genotype frequencies were determined using polymerase chain reaction and restriction enzyme digestion. No significant differences were detected in glutathione-S-transferase P1 and glutathione-S-transferase Z1 allele or genotype frequencies; however, a significant association between glutathione-S-transferase M1 genotypes and solar keratoses development was detected (p=0.003) with null individuals having an approximate 2-fold increase in risk for solar keratoses development (odds ratio: 2.1; confidence interval: 1.3-3.5) and a significantly higher increase in risk in conjunction with high outdoor exposure (odds ratio: 3.4; confidence interval: 1.9-6.3). Also, a difference in glutathione-S-transferase T1 genotype frequencies was detected (p=0.039), although considering that multiple testing was undertaken, this was found not to be significant. Fair skin and inability to tan were found to be highly significant risk factors for solar keratoses development with odds ratios of 18.5 (confidence interval: 5.7-59.9) and 7.4 (confidence interval: 2.6-21.0), respectively. Overall, glutathione-S-transferase M1 conferred a significant increase in risk of solar keratoses development, particularly in the presence of high outdoor exposure and synergistically with known phenotypic risk factors of fair skin and inability to tan.

Diurnal variation of small and large ion concentrations in an urban location

A Neutral cluster and Air Ion Spectrometer (NAIS) was used to monitor the concentration of airborne ions on 258 full days between Nov 2011 and Dec 2012 in Brisbane, Australia. The air was sampled from outside a window on the sixth floor of a building close to the city centre, approximately 100 m away from a busy freeway. The NAIS detects all ions and charged particles smaller than 42 nm. It was operated in a 4 min measurement cycle, with ion data recorded at 10 s intervals over 2 min during each cycle. The data were analysed to derive the diurnal variation of small, large and total ion concentrations in the environment. We adapt the definition of Horrak et al (2000) and classify small ions as molecular clusters smaller than 1.6 nm and large ions as charged particles larger than this size...

The null allele of GSTM1 does not affect susceptibility to solar keratoses in the Australian white population

Solar keratoses (SKs) are induced by exposure to UV radiation and are capable of undergoing transformation to squamous cell carcinoma (SCC).1 The two main factors influencing the occurrence of SK are the sensitivity of the skin to sunlight and the total duration of solar exposure. These factors are responsible for the high incidence of SK in Australia. Although the influence of genetic factors is not defined, there is evidence that the gene encoding the enzyme, glutathione S-transferase, may be implicated in cancer predisposition and therefore SK. Glutathione S-transferase Mu-1 (GSTM1) is an isoenzyme involved in the detoxification of carcinogens. The GSTM1 protein is completely absent in approximately 50% of white persons. This absence is caused by a homozygous gene deletion on chromosome 1p resulting in a null genotype.2 Katoh3 showed that the frequency of the GSTM1 null genotype was significantly higher in 85 patients with urothelial cancer (61.2%; p < 0.05), suggesting that the null genotype may increase cancer susceptibility. This finding was supported by Lafuente et al.4 who found evidence that persons who lack the GSTM1 gene have approximately twice the chance of experiencing malignant melanoma. Further research in the United Kingdom found that patients with two or more skin tumors of different types, basal cell carcinoma (BCC) and SCC, had a significantly higher frequency of GSTM1 null genotypes than controls (71%; p = 0.033). However the GSTM1 genotype in patients with only SCC was not excessive in this population.5 Persons residing in northern Australia have the highest incidence of nonmelanoma skin cancer (SCC and BCC) in the world6 and receive far greater solar exposure than persons residing in the United Kingdom. It is possible that the GSTM1 null genotype may affect susceptibility to SK, which may act as SCC precursors, in Australians exposed to these high levels of solar radiation.

The biology of the glutamatergic system and potential role in migraine

Migraine is a common genetically linked neurovascular disorder. Approximately ~12% of the Caucasian population are affected including 18% of adult women and 6% of adult men (1, 2). A notable female bias is observed in migraine prevalence studies with females affected ~3 times more than males and is credited to differences in hormone levels arising from reproductive achievements. Migraine is extremely debilitating with wide-ranging socioeconomic impact significantly affecting people's health and quality of life. A number of neurotransmitter systems have been implicated in migraine, the most studied include the serotonergic and dopaminergic systems. Extensive genetic research has been carried out to identify genetic variants that may alter the activity of a number of genes involved in synthesis and transport of neurotransmitters of these systems. The biology of the Glutamatergic system in migraine is the least studied however there is mounting evidence that its constituents could contribute to migraine. The discovery of antagonists that selectively block glutamate receptors has enabled studies on the physiologic role of glutamate, on one hand, and opened new perspectives pertaining to the potential therapeutic applications of glutamate receptor antagonists in diverse neurologic diseases. In this brief review, we discuss the biology of the Glutamatergic system in migraine outlining recent findings that support a role for altered Glutamatergic neurotransmission from biochemical and genetic studies in the manifestation of migraine and the implications of this on migraine treatment.

Immunosuppressive properties of mesenchymal stromal cell cultures derived from the limbus of human and rabbit corneas

Background aims Mesenchymal stromal cells (MSCs) cultivated from the corneal limbus (L-MSCs) provide a potential source of cells for corneal repair. In the present study, we investigated the immunosuppressive properties of human L-MSCs and putative rabbit L-MSCs to develop an allogeneic therapy and animal model of L-MSC transplantation. Methods MSC-like cultures were established from the limbal stroma of human and rabbit (New Zealand white) corneas using either serum-supplemented medium or a commercial serum-free MSC medium (MesenCult-XF Culture Kit; Stem Cell Technologies, Melbourne, Australia). L-MSC phenotype was examined by flow cytometry. The immunosuppressive properties of L-MSC cultures were assessed using mixed leukocyte reactions. L-MSC cultures were also tested for their ability to support colony formation by primary limbal epithelial (LE) cells. Results Human L-MSC cultures were typically CD34−, CD45− and HLA-DR− and CD73+, CD90+, CD105+ and HLA-ABC+. High levels (>80%) of CD146 expression were observed for L-MSC cultures grown in serum-supplemented medium but not cultures grown in MesenCult-XF (approximately 1%). Rabbit L-MSCs were approximately 95% positive for major histocompatibility complex class I and expressed lower levels of major histocompatibility complex class II (approximately 10%), CD45 (approximately 20%), CD105 (approximately 60%) and CD90 (<10%). Human L-MSCs and rabbit L-MSCs suppressed human T-cell proliferation by up to 75%. Conversely, L-MSCs from either species stimulated a 2-fold to 3-fold increase in LE cell colony formation. Conclusions L-MSCs display immunosuppressive qualities in addition to their established non-immunogenic profile and stimulate LE cell growth in vitro across species boundaries. These results support the potential use of allogeneic L-MSCs in the treatment of corneal disorders and suggest that the rabbit would provide a useful pre-clinical model.

Mathematical model of counter flow v-grove solar air collector

Double-pass counter flow v-grove collector is considered one of the most efficient solar air-collectors. In this design of the collector, the inlet air initially flows at the top part of the collector and changes direction once it reaches the end of the collector and flows below the collector to the outlet. A mathematical model is developed for this type of collector and simulation is carried out using MATLAB programme. The simulation results were verified with three distinguished research results and it was found that the simulation has the ability to predict the performance of the air collector accurately as proven by the comparison of experimental data with simulation. The difference between the predicted and experimental results is, at maximum, approximately 7% which is within the acceptable limit considering some uncertainties in the input parameter values to allow comparison. A parametric study was performed and it was found that solar radiation, inlet air temperature, flow rate and length has a significant effect on the efficiency of the air collector. Additionally, the results are compared with single flow V-groove collector.