Combination schemes for turning point prediction

We propose new forecast combination schemes for predicting turning points of business cycles. The combination schemes deal with the forecasting performance of a given set of models and possibly providing better turning point predictions. We consider turning point predictions generated by autoregressive (AR) and Markov-Switching AR models, which are commonly used for business cycle analysis. In order to account for parameter uncertainty we consider a Bayesian approach to both estimation and prediction and compare, in terms of statistical accuracy, the individual models and the combined turning point predictions for the United States and Euro area business cycles

In vitro modulation of inflammatory cytokine and IgG levels by extracts of Perna canaliculus

BACKGROUND: Inflammation is a predominant characteristic of autoimmune diseases which is characterized by the increased expression of pro-inflammatory cytokines. Soon to be published work from our laboratory has shown that ingestion of Perna canaliculus prevents the development of autoimmune diseases such as Systemic Lupus Erythematosus and rheumatoid arthritis in laboratory animals. The current paper attempts to illustrate how Perna can alleviate inflammation by modulating inflammatory cytokines, cyclooxygenase enzymes and Immunoglobulin-G (IgG) levels. METHODS: In the present study, hydrochloric acid [HCl] and Tween-20 were used to develop extracts of Perna. These extracts were assayed for protein content. Increasing concentrations of these extracts were then tested in cell culture for modulation of inflammatory cytokine, cyclooxygenase enzymes and IgG levels. Parallel tests were run using an available glycogen extract of Perna as a comparison to our in-house laboratory preparations. RESULTS: Tween-20 Perna extracts were found to be more stable and less toxic in cell culture than HCl digest of Perna. They also assayed higher in protein content that HCl extracts. Although both extracts inhibited IgG production in V2E9 hybridomas, Tween-20 extracts were more consistent in IgG suppression than HCl extracts. Overall Tween-20 extracts effectively decreased levels of TNF-α, IL-1, IL-2 and IL-6 as observed using cytokine bioassays. Twenty micrograms of Tween-20 Perna extracts induced such significant decreases in inflammatory cytokine production that when tested on sensitive cell lines, they very nearly abolished the decrease in viability induced by these cytokines. Tween-20 extracts effectively inhibited both COX-1 and COX-2 cyclooxygenase activity. As a comparison, the glycogen extract also demonstrated a similar though weaker effect on COX-1 and COX-2 enzymes. The active components of both extracts (Tween-20 and glycogen) were observed to possess molecular weights above 100 kDa. Although the anti-cytokine activity of the Tween-20 extract was destroyed by Proteinase-K treatment, the anti-COX-1 and anti-COX-2 activity of both the extracts were not sensitive to protease treatment. CONCLUSION: We have successfully demonstrated modulation in the levels of inflammatory cytokines, cyclooxygenase enzymes and immunoglobulins by our in-house laboratory preparations of Perna canaliculus, whereby suggesting an immunomodulatory role of Perna canaliculus in regulating inflammation

Chromosome abnormalities, mental retardation and the search for genes in bipolar disorder and schizophrenia

Genetic factors contribute to schizophrenia and bipolar disorder, and linkage and association studies have been successful in identifying several candidate genes. However these genes explain only a very small part of the total population risk and the psychoses appear to be very heterogeneous with several models of genetic inheritance relevant to different groups of patients, including some cases caused by multiple common genetic variants, while others are single gene disorders. Studying chromosomal abnormalities is a useful strategy for identifying genes in illness, and patients with both mental retardation and psychosis form a special group where large chromosomal abnormalities detected by routine cytogenetic analysis are more prevalent than in patients with schizophrenia or bipolar disorder alone, or in the general population. Studying these patients provides valuable opportunities to identify genes contributing to psychoses. This review of the literature on large chromosomal rearrangements in patients with mental retardation and psychotic illness illustrates how schizophrenia and bipolar phenotypes are associated with a large number of different chromosomal disruptions. Recent genome wide association studies have identified an excess of small chromosomal deletions and duplications in schizophrenia, adding further support to the importance of chromosomal structural variation in psychotic illness. The genes GRIK4 and NPAS3, each associated with psychosis in patients with mental retardation are discussed to illustrate the value of rare cytogenetic events as a means to signpost neurobiological pathways of general importance for illness in the wider population