Identification of a low molecular weight inhibitor of osteoblast mitogenesis in uremic plasma

Identification of a low molecular weight inhibitor of osteoblast mitogenesis in uremic plasma. A low molecular weight inhibitor of cartilage sulfation has been detected in the plasma of dialysis patients. Preliminary studies of this inhibitor have suggested that it may have a role in decreasing bone mass, possibly by suppressing bone cell proliferation. Since the in vitro bioassay of crude sulfation inhibitor preparations is relatively nonspecific, we investigated whether there might also be an inhibitor Of osteoblast mitogenesis in uremic plasma. We fractionated plasma and plasma ultrafiltrates from dialysis patients by gel filtration chromatography and looked for inhibition of mitogenesis in cultured osteoblasts. Material from fractions with a molecular weight range of 750 to 900 inhibited osteoblast mitogenesis. The inhibitory effect, however, could be overcome with serum or insulin-like growth factor-I, suggesting that the mechanism of inhibition was not growth factor dependent. Further characterization of the inhibitor revealed that it was not a peptide or a polar lipid. We conclude that uremic plasma contains a bone cell mitogenic inhibitor which may have a role in regulating bone remodeling in adults and bone growth in children

Glycosylation reduces the bioactivity of calcitonin

The biological significance of peptide hormone glycosylation is uncertain. To examine the effect of Asn-linked glycosylation on calcitonin's bioactivity we purified glycosylated calcitonin from a transplantable rat medullary thyroid carcinoma. Glycosylated calcitonin constituted 2.3% of the total extracted immunoreactive calcitonin. The structure of this peptide differed from nonglycosylated calcitonin only by the oligosaccharide modification of asparagine 3. Affinity of glycosylated calcitonin for lentil lectin indicated that the oligosaccharide was a complex processed form. In a standard in vivo bioassay glycosylated calcitonin had a markedly reduced hypocalcemic activity compared to nonglycosylated calcitonin, an effect most likely due to the presence of the oligosaccharide

The everyday experience of living with and managing a neurological condition (the LINC study): study design

Background: The impact of neurological conditions on individuals, families and society is increasing and having a significant economic impact in Canada. While some economic data is known, the human costs of living with a neurological condition are poorly understood and rarely factored into future burden analyses. The “Living with the Impact of a Neurological Condition (LINC)” study aims to fill this gap. It seeks to understand, for children and adults with neurological conditions, the supports and resources that make everyday life possible and meaningful. Methods/design: The LINC study is a nested study using mixed methods. We are interested in the following outcomes specifically: health status; resource utilization; self-management strategies; and participation. Three studies captured data from multiple sources, in multiple ways and from multiple perspectives. Study One: a populationbased survey of adults (n = 1500), aged 17 and over and parents (n = 200) of children aged 5 to 16 with a neurological condition. Study Two: a prospective cohort study of 140 adults and parents carried out using monthly telephone calls for 10 months; and Study Three: a multiple perspective case study (MPCS) of 12 adults and 6 parents of children with a neurological condition. For those individuals who participate in the MPCS, we will have data from all three studies giving us rich, in depth insights into their daily lives and how they cope with barriers to living in meaningful ways. Discussion: The LINC study will collect, for the first time in Canada, data that reflects the impact of living with a neurological condition from the perspectives of the individuals themselves. A variety of tools will be used in a combination, which is unique and innovative. This study will highlight the commonalities of burden that Canadians living with neurological conditions experience as well as their strategies for managing everyday life

Genome-wide association study identifies five susceptibility loci for glioma

To identify risk variants for glioma, we conducted a meta-analysis of two genome-wide association studies by genotyping 550K tagging SNPs in a total of 1,878 cases and 3,670 controls, with validation in three additional independent series totaling 2,545 cases and 2,953 controls. We identified five risk loci for glioma at 5p15.33 (rs2736100, TERT; P = 1.50 x 10(-17)), 8q24.21 (rs4295627, CCDC26; P = 2.34 x 10(-18)), 9p21.3 (rs4977756, CDKN2A-CDKN2B; P = 7.24 x 10(-15)), 20q13.33 (rs6010620, RTEL1; P = 2.52 x 10(-12)) and 11q23.3 (rs498872, PHLDB1; P = 1.07 x 10(-8)). These data show that common low-penetrance susceptibility alleles contribute to the risk of developing glioma and provide insight into disease causation of this primary brain tumor