The island species-area relationship (ISAR) describes how species richness increases with increasing area of a given island or island-like habitat, such as freshwater lakes. While the ISAR is one of the most common phenomena observed in ecology, there is variation in both the form of the relationship and its underlying mechanisms. We compiled a global data set of benthic macroinvertebrates from 524 shallow freshwater lakes, ranging from 1 to 293,300 ha in area.
View Article and Find Full Text PDFIn northern Alaska nearly 65% of the terrestrial surface is composed of polygonal ground, where geomorphic tundra landforms disproportionately influence carbon and nutrient cycling over fine spatial scales. Process-based biogeochemical models used for local to Pan-Arctic projections of ecological responses to climate change typically operate at coarse-scales (1km-0.5°) at which fine-scale (<1km) tundra heterogeneity is often aggregated to the dominant land cover unit.
View Article and Find Full Text PDFObjective: Altered immune reactivity precedes and accompanies type 1 and type 2 diabetes. We hypothesized that the metabolic phenotype relates to the systemic cellular immune status.
Research Design And Methods: A total of 194 metabolically well-controlled patients with type 1 diabetes (n = 62, mean diabetes duration 1.
A series of α7 nicotinic acetylcholine receptor full agonists with a 1,3,4-oxadiazol-2-amine core has been discovered. Early lead 1 was found to have a limited therapeutic index with respect to its potential for cardiovascular side effects. Further optimisation of this series led to the identification of 22 a potent full agonist showing efficacy at a dose of 0.
View Article and Find Full Text PDFA series of α7 nicotinic acetylcholine receptor full-agonists with a 1,3,4-oxadiazol-2-amine core has been discovered. Systematic exploration of the structure-activity relationships for both α7 potency and selectivity with respect to interaction with the hERG channel are described. Further profiling led to the identification of compound 22, a potent full agonist showing efficacy in the novel object recognition model of cognition enhancement.
View Article and Find Full Text PDFBackground: Type 1 diabetes (T1D) is a cell-mediated autoimmune disease characterized by destruction of the pancreatic islet cells. The use of cryopreserved cells is preferable to the use of freshly isolated cells to monitor clinical trials to decrease assay and laboratory variability.
Methods: The T-Cell Workshop Committee of the Immunology of Diabetes Society compared two widely accepted T-cell freezing protocols (warm and cold) to freshly isolated peripheral blood mononuclear cells from patients with T1D and controls in terms of recovery, viability, cell subset composition, and performance in functional assays currently in use in T1D-related research.
The peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated nuclear receptor, thought to play a role in energy metabolism, glucose homeostasis and microglia-mediated neuroinflammation. A novel benzimidazole series of centrally penetrant PPARγ partial agonists has been identified. The optimization of PPARγ activity and in vivo pharmacokinetics leading to the identification of GSK1997132B a potent, metabolically stable and centrally penetrant PPARγ partial agonist, is described.
View Article and Find Full Text PDFCapsaicin (vanilloid) sensitivity has long served as the functional signature of a subset of nociceptive sensory neurons. Mutagenesis studies have revealed seemingly distinct regions involved in mediating ligand binding and channel activation at the capsaicin binding site. Residue 547 (transmembrane region 4) mediates significant species differences in resiniferatoxin (RTX) sensitivity, and the Ser(512) residue is critical in discriminating between pH and capsaicin gating.
View Article and Find Full Text PDFIn undisturbed bone marrow, most hemopoietic stem cells are nonproliferating despite the presence of multiple growth factors. Endogenous inhibitory factors are responsible for maintenance of this quiescence. Previously we sequenced and synthesized the inhibitory pentapeptide pGlu-Glu-Asp-Cys-Lys (pEEDCK), which originally derives from granulocytes, and investigated the role of this peptide in stem cell quiescence.
View Article and Find Full Text PDFCongenital myasthenic syndrome comprises a heterogeneous group of inherited disorders of neuromuscular transmission. Acetylcholine receptor (AChR) deficiency is the most common form of congenital myasthenic syndrome and in most cases results from mutations within the coding region of the AChR epsilon subunit. However, studies in mice have established that synapse-specific expression of AChR is dependent on a sequence contained within the AChR-subunit promoter regions, termed an N-box.
View Article and Find Full Text PDFAm J Orthod Dentofacial Orthop
February 1990
The correction of two Class II, Division 2 malocclusions during the mixed dentition phase with the use of a Bionator appliance is presented. The suggestion that correction of Class II, Division 2 malocclusions may be achieved in the absence of fixed appliances is supported in these case reports.
View Article and Find Full Text PDFThe nucleo-, phospho- and matrix protein of measles virus were localized at high resolution within infected cells by use of post-embedding immunogold labelling techniques. In general, labelling with monospecific antibodies as well as with a polyvalent rabbit anti-measles hyperimmune antiserum revealed measles virus polypeptides to be distributed non-randomly within infected cells with the label largely confined to specific sites, namely inclusions of nucleocapsids and assembled virus structures at the plasma membrane. Immunogold double labelling indicated that the phosphoprotein strictly co-localized with the nucleoprotein in cytoplasmic inclusions of nucleocapsids and in budding virions, whereas intranuclear inclusions of nucleocapsids were devoid of phosphoprotein labelling.
View Article and Find Full Text PDFThe pathogenesis of macrovascular disease in diabetes mellitus is still incompletely understood. Within the various pathomechanisms abnormal growth of vascular cells is well established as an intrinsic part of the angiopathic process. In this regard, there are different groups of vascular growth factors that are of potential relevance for the development of macrovascular disease in diabetes : hormones, locally released growth factors of platelet and of arterial wall cell origin.
View Article and Find Full Text PDFPremature atherosclerosis in hypercholesterolemic patients may be due, in part, to increased growth of vascular cells. Therefore, the growth stimulating effect of serum and serum fractions from patients with primary hyper-LDL-cholesterolemia (LDL-cholesterol: 7.5 +/- 1.
View Article and Find Full Text PDFDiabetic angiopathy may be due, in part, to increased growth in vascular cells. We have investigated serum growth factors in Type 2 (non-insulin-dependent) diabetic and healthy subjects and their effect on cultured human arterial smooth muscle cells and fibroblasts. Removal of the dialyzable serum fraction (mol.
View Article and Find Full Text PDFHorm Metab Res Suppl
February 1986
There are two different classes of humoral growth factors for arterial smooth muscle and endothelial cells that age of potential relevance for the development of macrovascular disease inn diabetes mellitus: hormones (growth hormone, insulin like growth factor I and II, insulin) and locally released growth factors of platelet origin. The following hormones have to be considered: Increased growth hormone plasma levels might contribute to macrovascular disease, but its actual relevance remains to be determined. Insulin like growth factor I and II are present in vivo and stimulate growth of vascular cells in vitro but their relevance for macrovascular disease in diabetes is unproven.
View Article and Find Full Text PDFThe green primary compound of chloroperoxidase was prepared by freeze-quenching the enzyme after rapid mixing with a 5-fold excess of peracetic acid. The electron paramagnetic resonance (EPR) spectra of these preparations consisted of at least three distinct signals that could be assigned to native enzyme, a free radical, and the green compound I as reported earlier. The absorption spectrum of compound I was obtained through subtraction of EPR signals measured under passage conditions.
View Article and Find Full Text PDFWe report Mössbauer and EPR measurements on horseradish peroxidase in the native state and the reaction intermediates with peroxide and chlorite. A detailed analysis of the electronic state of the heme iron is given, and comparisons are drawn with related systems. The native enzyme is high-spin ferric and thus has three Kramers doublets.
View Article and Find Full Text PDFThe electron paramagnetic resonance (EPR) and Mössbauer properties of native horseradish peroxidase have been compared with those of a synthetic derivative of the enzyme in which a mesohemin residue replaces the natural iron protoporphyrin IX heme prosthetic group. The oxyferryl pi cation radical intermediate, compound I, has been formed from both the native and synthetic enzyme, and the magnetic properties of both intermediates have been examined. The optical absorption characteristics of compound I prepared from mesoheme-substituted horseradish peroxidase are different from those of the compound I prepared from native enzyme [DiNello, R.
View Article and Find Full Text PDFFrom the temperature dependence of the Orbach relaxation rate of the paramagnetic center in horseradish peroxidase (HRP), we deduce an excited-state energy of 40.9 +/- 1.1 K.
View Article and Find Full Text PDFThe electron paramagnetic resonance spectra of chloroperoxidase Compound I and native enzyme are compared. Upon the formation of Compound I, the g = 2.62, 2.
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