Effects of medical history and clinical factors on serum lipase activity and ultrasonographic evidence of pancreatitis: Analysis of 234 dogs

Background: Lipase measurements and ultrasonographic (US) evidence of pancreatitis correlate poorly. Objectives: Identify explanations for discrepant lipase and pancreatic US results. Animals: Two hundred and thirty-four dogs with gastrointestinal signs. Methods: A retrospective study was conducted, in which lipase activity and US were performed within 30 hours. Medical history, clinical examination results, lipase activity, and US results were recorded. Results: Lipase and US results were weakly correlated (rs = .25, P 2 days, 118 U/L; P = .03; ≤7 days, 334 U/L; >7 days, 99 U/L; P = .004), but US was not significantly more frequently positive. For both cut-offs (>216/≤216 U/L, >355/≤355 U/L; reference range, 24-108 U/L), median disease duration was significantly shorter (3 vs 4 days) with higher lipases. Previous pancreatitis episodes were significantly associated with an US diagnosis of pancreatitis (P = .04), but median lipase activities were not significantly higher (386 U/L vs 153 U/L; P = .06) in these dogs. Pancreatic US was significantly more often positive when the request contained "suspicion of pancreatitis" (P < .001) or "increased lipase" (P = .01). Only changes in pancreatic morphology, echogenicity, and peripancreatic mesentery were significantly associated with a positive US diagnosis, and also had significantly higher lipase activities. Conclusions and clinical importance: Duration of clinical signs before presentation differently affects laboratory and US evidence of pancreatitis. Previous pancreatitis episodes and information given to radiologists influence US results. These findings can be helpful for future studies on pancreatitis in dogs

Mesenchymal stromal/stem cells as potential therapy in diabetic retinopathy

Diabetic retinopathy (DR) is a multifactorial microvascular disease induced by hyperglycemia and subsequent metabolic abnormalities. The resulting cell stress causes a sequela of events that ultimately can lead to severe vision impairment and blindness. The early stages are characterized by activation of glia and loss of pericytes, endothelial cells (EC) and neuronal cells. The integrity of the retinal microvasculature becomes affected, and, as a possible late response, macular edema may develop as a common reason for vision loss in patients with non proliferative DR. Moreover, the local ischemia can trigger vasoproliferation leading to vision-threating proliferative DR (PDR) in humans. Available treatment options include control of metabolic and hemodynamic factors. Timely intervention of advanced DR stages with laser photocoagulation, intraocular anti-vascular endothelial growth factor (VEGF) or glucocorticoid drugs can reduce vision loss. As the pathology involves cell loss of both the vascular and neuroglial compartments, cell replacement strategies by stem and progenitor cells have gained considerable interest in the past years. Compared to other disease entities, so far little is known about the efficacy and potential mode of action of cell therapy in treatment of DR. In preclinical models of DR different cell types have been applied ranging from embryonic or induced pluripotent stem cells, hematopoietic stem cells, and endothelial progenitor cells to mesenchymal stromal cells (MSC). The latter cell population can combine various modes of action (MoA), thus they are among the most intensely tested cell types in cell therapy. The aim of this review is to discuss the rationale for using MSC as potential cell therapy to treat DR. Accordingly, we will revise identified MoA of MSCs and speculate how these may support the repair of the damaged retina

Pro-angiogenic Activity Discriminates Human Adipose-Derived Stromal Cells From Retinal Pericytes: Considerations for Cell-Based Therapy of Diabetic Retinopathy

Diabetic retinopathy (DR) is a frequent diabetes-associated complication. Pericyte dropout can cause increased vascular permeability and contribute to vascular occlusion. Adipose-derived stromal cells (ASC) have been suggested to replace pericytes and restore microvascular support as potential therapy of DR. In models of DR, ASC not only generated a cytoprotective and reparative environment by the secretion of trophic factors but also engrafted and integrated into the retina in a pericyte-like fashion. The aim of this study was to compare the pro-angiogenic features of human ASC and human retinal microvascular pericytes (HRMVPC) in vitro. The proliferation and the expression of ASC and HRMVPC markers were compared. Adhesion to high glucose-conditioned endothelial extracellular matrix, mimicking the diabetic microenvironment, was measured. The angiogenesis-promoting features of both cell types and their conditioned media on human retinal endothelial cells (EC) were assessed. To identify a molecular basis for the observed differences, gene expression profiling was performed using whole-genome microarrays, and data were validated using PCR arrays and flow cytometry. Based on multiplex cytokine results, functional studies on selected growth factors were performed to assess their role in angiogenic support. Despite a distinct heterogeneity in ASC and HRMVPC cultures with an overlap of expressed markers, ASC differed functionally from HRMVPC. Most importantly, the pro-angiogenic activity was solely featured by ASC, whereas HRMVPC actively suppressed vascular network formation. HRMVPC, in contrast to ASC, showed impaired adhesion and proliferation on the high glucose-conditioned endothelial extracellular matrix. These data were supported by gene expression profiles with differentially expressed genes. The vessel-stabilizing factors were more highly expressed in HRMVPC, and the angiogenesis-promoting factors were more highly expressed in ASC. The vascular endothelial growth factor receptor-2 inhibition efficiently abolished the ASC angiogenic supportive capacities, whereas the addition of angiopoietin-1 and angiopoietin-2 did not alter these effects. Our results clearly show that ASC are pro-angiogenic, whereas HRMVPC are marked by anti-angiogenic/EC-stabilizing features. These data support ASC as pericyte replacement in DR but also suggest a careful risk-to-benefit analysis to take full advantage of the ASC therapeutic features

Pro-angiogenic Activity Discriminates Human Adipose-Derived Stromal Cells From Retinal Pericytes: Considerations for Cell-Based Therapy of Diabetic Retinopathy

Diabetic retinopathy (DR) is a frequent diabetes-associated complication. Pericyte dropout can cause increased vascular permeability and contribute to vascular occlusion. Adipose-derived stromal cells (ASC) have been suggested to replace pericytes and restore microvascular support as potential therapy of DR. In models of DR, ASC not only generated a cytoprotective and reparative environment by the secretion of trophic factors but also engrafted and integrated into the retina in a pericyte-like fashion. The aim of this study was to compare the pro-angiogenic features of human ASC and human retinal microvascular pericytes (HRMVPC) in vitro. The proliferation and the expression of ASC and HRMVPC markers were compared. Adhesion to high glucose-conditioned endothelial extracellular matrix, mimicking the diabetic microenvironment, was measured. The angiogenesis-promoting features of both cell types and their conditioned media on human retinal endothelial cells (EC) were assessed. To identify a molecular basis for the observed differences, gene expression profiling was performed using whole-genome microarrays, and data were validated using PCR arrays and flow cytometry. Based on multiplex cytokine results, functional studies on selected growth factors were performed to assess their role in angiogenic support. Despite a distinct heterogeneity in ASC and HRMVPC cultures with an overlap of expressed markers, ASC differed functionally from HRMVPC. Most importantly, the pro-angiogenic activity was solely featured by ASC, whereas HRMVPC actively suppressed vascular network formation. HRMVPC, in contrast to ASC, showed impaired adhesion and proliferation on the high glucose-conditioned endothelial extracellular matrix. These data were supported by gene expression profiles with differentially expressed genes. The vessel-stabilizing factors were more highly expressed in HRMVPC, and the angiogenesis-promoting factors were more highly expressed in ASC. The vascular endothelial growth factor receptor-2 inhibition efficiently abolished the ASC angiogenic supportive capacities, whereas the addition of angiopoietin-1 and angiopoietin-2 did not alter these effects. Our results clearly show that ASC are pro-angiogenic, whereas HRMVPC are marked by anti-angiogenic/EC-stabilizing features. These data support ASC as pericyte replacement in DR but also suggest a careful risk-to-benefit analysis to take full advantage of the ASC therapeutic features

Marked isotopic variability within and between the Amazon River and marine dissolved black carbon pools

Riverine dissolved organic carbon (DOC) contains charcoal byproducts, termed black carbon (BC). To determine the significance of BC as a sink of atmospheric CO2 and reconcile budgets, the sources and fate of this large, slow-cycling and elusive carbon pool must be constrained. The Amazon River is a significant part of global BC cycling because it exports an order of magnitude more DOC, and thus dissolved BC (DBC), than any other river. We report spatially resolved DBC quantity and radiocarbon (Δ14C) measurements, paired with molecular-level characterization of dissolved organic matter from the Amazon River and tributaries during low discharge. The proportion of BC-like polycyclic aromatic structures decreases downstream, but marked spatial variability in abundance and Δ14C values of DBC molecular markers imply dynamic sources and cycling in a manner that is incongruent with bulk DOC. We estimate a flux from the Amazon River of 1.9–2.7 Tg DBC yr−1 that is composed of predominately young DBC, suggesting that loss processes of modern DBC are important

Alternative Splicing in the Differentiation of Human Embryonic Stem Cells into Cardiac Precursors

The role of alternative splicing in self-renewal, pluripotency and tissue lineage specification of human embryonic stem cells (hESCs) is largely unknown. To better define these regulatory cues, we modified the H9 hESC line to allow selection of pluripotent hESCs by neomycin resistance and cardiac progenitors by puromycin resistance. Exon-level microarray expression data from undifferentiated hESCs and cardiac and neural precursors were used to identify splice isoforms with cardiac-restricted or common cardiac/neural differentiation expression patterns. Splice events for these groups corresponded to the pathways of cytoskeletal remodeling, RNA splicing, muscle specification, and cell cycle checkpoint control as well as genes with serine/threonine kinase and helicase activity. Using a new program named AltAnalyze (http://www.AltAnalyze.org), we identified novel changes in protein domain and microRNA binding site architecture that were predicted to affect protein function and expression. These included an enrichment of splice isoforms that oppose cell-cycle arrest in hESCs and that promote calcium signaling and cardiac development in cardiac precursors. By combining genome-wide predictions of alternative splicing with new functional annotations, our data suggest potential mechanisms that may influence lineage commitment and hESC maintenance at the level of specific splice isoforms and microRNA regulation

Analysis and fate of combustion residues in soil

Combustion residues from biomass and fossil fuel burning, called black carbon (BC), make up a small but very significant part of the global carbon cycle. These residues are universally found in soils, lacustrine and marine sediments and the atmosphere. They can be involved in important global processes, including carbon sequestration, pollutant binding, solar radiation reactions and can also be used to reconstruct fire histories. Black carbon does not have a defined structure, and since it represents combustion residues and condensates from various sources, it is viewed as a combustion continuum, ranging from slightly charred biomass to highly condensed soot, rather than one substance. There are a variety of methods, each quantifying a different part of the combustion continuum and overlapping in detection regions in some cases. Results from these different methods are not comparable, and therefore compiling a composite picture of BC concentrations in the environment is difficult. Reference materials analysed for BC with different methods would assist in drawing conclusions from and elucidating incomparable results. A structured means of achieving such a goal would be an intercomparative study where a number of laboratories employing different methods, all measure these reference materials for black carbon, and compare results. In this study, 12 reference materials from different environments were chosen to serve as reference materials in standardising and validating BC results from various methods. The materials are divided into three sets: (i) laboratory-produced BC-rich materials (n-hexane soot, wood char, grass char); (ii) non-BC materials that could potentially interfere with analysis (melanoidin, shale, bituminous coal, lignite coal); and (iii) environmental matrices that probably contain BC (urban aerosol, harbour marine sediment, two soils, dissolved organic matter). Char reference materials did not exist, and were specifically synthesised. They were chemically characterised, compared to other synthesised and natural chars and found to represent charcoal from typical low temperature fires. All twelve materials were used in a intercomparative study of black carbon quantification techniques, involving 17 international laboratories, employing seven different thermal and chemical oxidation methods. The results for all the materials analysed with the different methods were very disparate. Most methods quantified black carbon in the BC-rich materials, except two, whose harsh oxidation techniques oxidised all the carbon in the charcoals. Many methods found BC in the non-BC materials, thereby failing to exclude biases from these potential interfering materials. There was a large variation in concentrations of BC measured in the environmental samples. The chemical and physical properties of the materials were studied to elucidate how they influenced the BC quantification with different methods. The BC-rich materials were very similar, but the soot had a more condensed structure than the chars. The non-BC potentially interfering materials share properties with the BC-rich materials, which could lead to false positive data from non-BC materials and an overestimation of BC. The environmental matrices have relatively high amounts of inorganic matter and metal oxides, which have the potential to catalyse or inhibit thermal and chemical reactions in black carbon analysis. This study shows that any attempt to merge data generated via different methods must consider the different, operationally defined analytical windows of the BC continuum detected by each technique, as well as the limitations and potential biases of each technique. The benzene polycarboxylic acid markers method, employed in the ring trial by our laboratory, gave reasonable results for all the materials, in particular the soil matrices, for which this method was designed. We used this method in a case study to quantify the BC stock in a BC-rich steppe soil in Russia. This soil was sampled twice, 100 years apart, and we determined a BC stock loss of 25% over the whole soil profile (up to 130 cm). We used these stock values to calculate a BC turnover rate of 212-541 years for this soil, according to different assumptions, which is two to five times faster than the turnover (100 years) currently ascribed to inert carbon by the Intergovernmental Panel on Climate Change. Thus, BC in soil is not as stable as is currently assumed. Because fossil fuel burning and vegetation fires will probably increase in future, it will be important to quantify the potential of BC as a carbon sink in soils and sediments. In the foreseeable future, BC method standardisation and calibration will be a continuing process