Bayesian Wavelet Shrinkage of the Haar-Fisz Transformed Wavelet Periodogram.

It is increasingly being realised that many real world time series are not stationary and exhibit evolving second-order autocovariance or spectral structure. This article introduces a Bayesian approach for modelling the evolving wavelet spectrum of a locally stationary wavelet time series. Our new method works by combining the advantages of a Haar-Fisz transformed spectrum with a simple, but powerful, Bayesian wavelet shrinkage method. Our new method produces excellent and stable spectral estimates and this is demonstrated via simulated data and on differenced infant electrocardiogram data. A major additional benefit of the Bayesian paradigm is that we obtain rigorous and useful credible intervals of the evolving spectral structure. We show how the Bayesian credible intervals provide extra insight into the infant electrocardiogram data

The chrondoprotective actions of a natural product are associated with the activation of IGF-1 production by human chondrocytes despite the presence of IL-1β

BACKGROUND: Cartilage loss is a hallmark of arthritis and follows activation of catabolic processes concomitant with a disruption of anabolic pathways like insulin-like growth factor 1 (IGF-1). We hypothesized that two natural products of South American origin, would limit cartilage degradation by respectively suppressing catabolism and activating local IGF-1 anabolic pathways. One extract, derived from cat's claw (Uncaria guianensis, vincaria(®)), is a well-described inhibitor of NF-κB. The other extract, derived from the vegetable Lepidium meyenii (RNI 249), possessed an uncertain mechanism of action but with defined ethnomedical applications for fertility and vitality. METHODS: Human cartilage samples were procured from surgical specimens with consent, and were evaluated either as explants or as primary chondrocytes prepared after enzymatic digestion of cartilage matrix. Assessments included IGF-1 gene expression, IGF-1 production (ELISA), cartilage matrix degradation and nitric oxide (NO) production, under basal conditions and in the presence of IL-1β. RESULTS: RNI 249 enhanced basal IGF-1 mRNA levels in human chondrocytes by 2.7 fold, an effect that was further enhanced to 3.8 fold by co-administration with vincaria. Enhanced basal IGF-1 production by RNI 249 alone and together with vincaria, was confirmed in both explants and in primary chondrocytes (P <0.05). As expected, IL-1β exposure completely silenced IGF-1 production by chondrocytes. However, in the presence of IL-1β both RNI 249 and vincaria protected IGF-1 production in an additive manner (P <0.01) with the combination restoring chondrocyte IGF-1 production to normal levels. Cartilage NO production was dramatically enhanced by IL-1β. Both vincaria and RNI 249 partially attenuated NO production in an additive manner (p < 0.05). IL-1β – induced degradation of cartilage matrix was quantified as glycosaminoglycan release. Individually RNI 249 or vincaria, prevented this catabolic action of IL-1β. CONCLUSION: The identification of agents that activate the autocrine production of IGF-1 in cartilage, even in the face of suppressive pro-inflammatory, catabolic cytokines like IL-1β, represents a novel therapeutic approach to cartilage biology. Chondroprotection associated with prevention of the catabolic events and the potential for sustained anabolic activity with this natural product suggests that it holds significant promise in the treatment of debilitating joint diseases

Growth And The Growth Hormone-Insulin Like Growth Factor 1 Axis In Children With Chronic Inflammation:Current Evidence, Gaps In Knowledge And Future Directions

Growth failure is frequently encountered in children with chronic inflammatory conditions like juvenile idiopathic arthritis, inflammatory bowel disease and cystic fibrosis. Delayed puberty and attenuated pubertal growth spurt is often seen during adolescence. The underlying inflammatory state mediated by pro-inflammatory cytokines, prolonged use of glucocorticoid and suboptimal nutrition contribute to growth failure and pubertal abnormalities. These factors can impair growth by their effects on the growth hormone-insulin like growth factor axis and also directly at the level of the growth plate via alterations in chondrogenesis and local growth factor signaling. Recent studies on the impact of cytokines and glucocorticoid on the growth plate studies further advanced our understanding of growth failure in chronic disease and provided a biological rationale of growth promotion. Targeting cytokines using biologic therapy may lead to improvement of growth in some of these children but approximately one third continue to grow slowly. There is increasing evidence that the use of relatively high dose recombinant human growth hormone may lead to partial catch up growth in chronic inflammatory conditions, although long term follow-up data is currently limited. In this review, we comprehensively review the growth abnormalities in children with juvenile idiopathic arthritis, inflammatory bowel disease and cystic fibrosis, systemic abnormalities of the growth hormone-insulin like growth factor axis and growth plate perturbations. We also systematically reviewed all the current published studies of recombinant human growth hormone in these conditions and discuss the role of recombinant human insulin like growth factor-1

Presenting features of inflammatory bowel disease in Great Britain and Ireland

Background: Reports from individual referral centres suggest that a significant proportion of children with inflammatory bowel disease (IBD) present after prolonged delays and with impaired growth. Aims: To prospectively document the presenting features, delay in presentation, disease localisation, and growth in newly diagnosed cases of IBD. Methods: For 13 months, between June 1998 and June 1999, 3247 paediatricians, adult gastroenterologists, and surgeons across the UK and Ireland were prospectively surveyed each month and asked to report every newly diagnosed case of childhood IBD. Results: A total of 739 new IBD cases aged less than 16 years were identified. Only one quarter of Crohn's disease (CD) cases presented with the "classic triad" of diarrhoea, weight loss, and abdominal pain; nearly half did not report diarrhoea. The median delay from onset of symptoms to diagnosis was 5 months (mean 11 months), with one fifth having symptoms of more than one year. Delays were most common in CD and in younger children. Short stature was noted only in those with CD and not with ulcerative colitis. One fifth of CD cases had disease activity in the jejunum and this group had significantly reduced stature. Ileo-colonic involvement was documented in most CD cases, with only a small minority having isolated ileal or isolated colonic disease. Pan-colitis was reported in most UC cases, with very few having only an isolated proctitis. Conclusions: Many children are diagnosed after prolonged delays and have growth failure. Improved knowledge of the presenting features of IBD, and earlier investigation of suspected cases, may help reduce the delays noted

Variations in initial assessment and management of inflammatory bowel disease across Great Britain and Ireland

Background: There are no published data from Great Britain and Ireland detailing the initial management of children with inflammatory bowel disease (IBD). Aims: To prospectively record the initial investigation and treatment of children aged less than 16 years with newly diagnosed IBD. Methods: For 13 months, between June 1998 and June 1999, 3247 paediatricians, adult gastroenterologists, and surgeons across the UK and Ireland were prospectively surveyed each month and asked to report every newly diagnosed case of childhood IBD. Reporters subsequently completed a postal questionnaire about each case. Results: A total of 739 new IBD cases were reported from 172 institutions. Significant variations were observed in the investigation and treatment of these cases, when examined by number of cases reported per institution, or by the specialists providing care. There were wide regional variations in the proportion of children having access to paediatric gastroenterology services. Overall, one third of children received care from an adult service, and a tenth care exclusively from an adult gastroenterologist. Children with Crohn's disease who had some or all of their care from adult services were more likely to receive systemic steroids and less likely to receive dietary therapy; those with ulcerative colitis were more likely to receive rectal steroids and to have surgery. Height and weight were also less likely to be recorded in those whose care involved adult services. Conclusion: Current specialist provision, and initial investigation and treatment of IBD, is heterogeneous. Optimisation of care is likely to be achieved by greater access to specialist paediatric gastroenterology services for all those with suspected IBD