Net primary productivity and litter decomposition rates in two distinct Amazonian peatlands.

Measurements of net primary productivity (NPP) and litter decomposition from tropical peatlands are severely lacking, limiting our ability to parameterise and validate models of tropical peatland development and thereby make robust predictions of how these systems will respond to future environmental and climatic change. Here, we present total NPP (i.e., above- and below-ground) and decomposition data from two floristically and structurally distinct forested peatland sites within the Pastaza Marañón Foreland Basin, northern Peru, the largest tropical peatland area in Amazonia: (1) a palm (largely Mauritia flexuosa) dominated swamp forest and (2) a hardwood dominated swamp forest (known as 'pole forest', due to the abundance of thin-stemmed trees). Total NPP in the palm forest and hardwood-dominated forest (9.83 ± 1.43 and 7.34 ± 0.84 Mg C ha-1 year-1, respectively) was low compared with values reported for terra firme forest in the region (14.21-15.01 Mg C ha-1 year-1) and for tropical peatlands elsewhere (11.06 and 13.20 Mg C ha-1 year-1). Despite the similar total NPP of the two forest types, there were considerable differences in the distribution of NPP. Fine root NPP was seven times higher in the palm forest (4.56 ± 1.05 Mg C ha-1 year-1) than in the hardwood forest (0.61 ± 0.22 Mg C ha-1 year-1). Above-ground palm NPP, a frequently overlooked component, made large contributions to total NPP in the palm-dominated forest, accounting for 41% (14% in the hardwood-dominated forest). Conversely, Mauritia flexuosa litter decomposition rates were the same in both plots: highest for leaf material, followed by root and then stem material (21%, 77% and 86% of mass remaining after 1 year respectively for both plots). Our results suggest potential differences in these two peatland types' responses to climate and other environmental changes and will assist in future modelling studies of these systems.

Mediciones de la productividad primaria neta (PPN) y la descomposición de materia orgánica de las turberas tropicales son escasas, lo que limita nuestra capacidad para parametrizar y validar modelos de desarrollo de las turberas tropicales y, en consecuencia, realizar predicciones sólidas sobre la respuesta de estos sistemas ante futuros cambios ambientales y climáticos. En este estudio, presentamos datos de PPN total (es decir, biomasa aérea y subterránea) y descomposición de la materia orgánica colectada en dos turberas boscosas con características florísticas y estructurales contrastantes dentro de la cuenca Pastaza Marañón al norte del Perú, el área de turberas tropicales más grande de la Amazonia: (1) un bosque pantanoso dominado por palmeras (principalmente Mauritia flexuosa) y (2) un bosque pantanosos dominado por árboles leñosos de tallo delgado (conocido como 'varillal hidromórfico'). La PPN total en el bosque de palmeras y el varillal hidromórfico (9,83 ± 1,43 y 7,34 ± 0,84 Mg C ha­1 año­1 respectivamente) fue baja en comparación con los valores reportados para los bosques de tierra firme en la región (14,21­15,01 Mg C ha­1 año­1) y para turberas tropicales en otros lugares (11,06 y 13,20 Mg C ha­1 año­1). A pesar de que la PPN total fue similar en ambos tipos de bosque, hubo diferencias considerables en la distribución de la PPN. La PPN de las raíces finas fue siete veces mayor en el bosque de palmeras (4,56 ± 1,05 Mg C ha­1 año­1) que en el varillal hidromórfico (0,61 ± 0,22 Mg C ha­1 año­1). La PPN de la biomasa aérea de las palmeras, un componente ignorado frecuentemente, contribuyó en gran medida a la PPN total del bosque de palmeras, representando el 41% (14% en el varillal hidromórfico). Por el contrario, la tasa de descomposición de materia orgánica de Mauritia flexuosa fue la misma en ambos sitios: la más alta corresponde a la hojarasca, seguida por las raíces y luego el tallo (21%, 77% y 86% de la masa restante después de un año, respectivamente para ambos sitios). Nuestros resultados sugieren diferencias potenciales en la respuesta de estos dos tipos de turberas al clima y otros cambios ambientales, y ayudarán en futuros estudios de modelamiento de estos sistemas.

Long-term decline of the Amazon carbon sink.

Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.

Characterising recovery following abdominal aortic aneurysm repair using cardiopulmonary exercise testing and patient reported outcome measures.

PURPOSE: Surgery is associated with a post-operative stress response, changes in cardiopulmonary reserve, and metabolic demand. Here recovery after abdominal aortic aneurysm repair is investigated using cardiopulmonary exercise testing and patient-reported questionnaires. MATERIALS AND METHODS: Patients undergoing open (n = 21) or endovascular (n = 21) repair undertook cardiopulmonary exercise tests, activity, and health score questionnaires pre-operatively and, 8 and 16 weeks, post-operatively. Oxygen uptake and ventilatory parameters were measured, and routine blood tests were undertaken. RESULTS: Recovery was characterised by falls in anaerobic threshold, peak oxygen uptake, and oxygen pulse at 8 weeks which appeared to be associated with operative severity; the fall in peak oxygen uptake was greater following open vs. endovascular repair (3.5 vs. 1.6 ml.kg-1.min-1) and anaerobic threshold showed a similar tendency (3.1 vs. 1.7 ml.kg-1.min-1). In the smaller number of patients re-tested these changes resolved by 16 weeks. Reported health and activity did not change. CONCLUSIONS: Aortic repair is associated with falls in the anaerobic threshold, peak oxygen uptake, and oxygen pulse of a magnitude that reflects operative severity and appears to resolve by 16 weeks. Thus, post-operatively patients may be at higher risk of further metabolic insult e.g. infection. This further characterises physiological recovery from aortic surgery and may assist in defining post-operative shielding time.IMPLICATIONS FOR REHABILITATIONAbdominal aortic aneurysm repair is a life-saving operation, the outcome from which is influenced by pre-operative cardiopulmonary reserve; individuals with poor reserve being at greater risk of peri-operative complications and death. However, for this operation, the physiological impact of surgery has not been studied.In a relatively small sample, this study suggests that AAA repair is associated with a significant decline in cardiopulmonary reserve when measured 8 weeks post-operatively and appears to recover by 16 weeks. Moreover, the impact may be greater in endovascular vs. open repair.

Mapping socio-economic scenarios of land cover change: a GIS method to enable ecosystem service modelling.

We present a GIS method to interpret qualitatively expressed socio-economic scenarios in quantitative map-based terms. (i) We built scenarios using local stakeholders and experts to define how major land cover classes may change under different sets of drivers; (ii) we formalized these as spatially explicit rules, for example agriculture can only occur on certain soil types; (iii) we created a future land cover map which can then be used to model ecosystem services. We illustrate this for carbon storage in the Eastern Arc Mountains of Tanzania using two scenarios: the first based on sustainable development, the second based on 'business as usual' with continued forest-woodland degradation and poor protection of existing forest reserves. Between 2000 and 2025 4% of carbon stocks were lost under the first scenario compared to a loss of 41% of carbon stocks under the second scenario. Quantifying the impacts of differing future scenarios using the method we document here will be important if payments for ecosystem services are to be used to change policy in order to maintain critical ecosystem services.

Weighing trees with lasers: advances, challenges and opportunities.

Terrestrial laser scanning (TLS) is providing exciting new ways to quantify tree and forest structure, particularly above-ground biomass (AGB). We show how TLS can address some of the key uncertainties and limitations of current approaches to estimating AGB based on empirical allometric scaling equations (ASEs) that underpin all large-scale estimates of AGB. TLS provides extremely detailed non-destructive measurements of tree form independent of tree size and shape. We show examples of three-dimensional (3D) TLS measurements from various tropical and temperate forests and describe how the resulting TLS point clouds can be used to produce quantitative 3D models of branch and trunk size, shape and distribution. These models can drastically improve estimates of AGB, provide new, improved large-scale ASEs, and deliver insights into a range of fundamental tree properties related to structure. Large quantities of detailed measurements of individual 3D tree structure also have the potential to open new and exciting avenues of research in areas where difficulties of measurement have until now prevented statistical approaches to detecting and understanding underlying patterns of scaling, form and function. We discuss these opportunities and some of the challenges that remain to be overcome to enable wider adoption of TLS methods.

Genomewide association study reveals a risk locus for equine metabolic syndrome in the Arabian horse.

Equine obesity can cause life-threatening secondary chronic conditions, similar to those in humans and other animal species. Equine metabolic syndrome (EMS), primarily characterized by hyperinsulinemia, is often present in obese horses and ponies. Due to clinical similarities to conditions such as pituitary pars intermedia dysfunction (formerly equine Cushing's disease), conclusive diagnosis of EMS often proves challenging. Aside from changes in diet and exercise, few targeted treatments are available for EMS, emphasizing the need for early identification of at-risk individuals to enable implementation of preventative measures. A genomewide association study (GWAS) using Arabian horses with a history of severe laminitis secondary to EMS revealed significant genetic markers near a single candidate gene () that may play a role in cholesterol homeostasis. The best marker, BIEC2-263524 (chr14:69276814 T > C), was correlated with elevated insulin values and increased frequency of laminitis ( = 0.0024 and = 9.663 × 10, respectively). In a second population of Arabian horses, the BIEC2-263524 marker maintained its associations with higher modified insulin-to-glucose ratio (MIRG) values ( = 0.0056) and BCS ( = 0.0063). Screening of the predicted coding regions by sequencing identified a polymorphic guanine homopolymer and 5 haplotypes in the 3' untranslated region (UTR). An 11 guanine (11-G) allele at was correlated with elevated insulin values in the GWAS population ( = 0.0008) and, in the second population, elevated MIRG and increased BCS > 6.5 ( = 0.0055 and = 0.0162, respectively). The BIEC2-263524-C and the 3' UTR -11(G) polymorphisms were correlated at a 98% frequency, indicating strong linkage disequilibrium across this 150-kb haplotype. Assays for these markers could diagnose horses with a genetic predisposition to develop obesity. Additionally, discovery of FAM174A function may improve our understanding of the etiology of this troubling illness in the horse and warrants investigation of this locus for a role in metabolic- and obesity-related disorders of other species.

Successful lung transplantation in spite of cystic fibrosis-associated liver disease: a case series.

Lung transplantation has recently offered hope for prolonged survival in patients with cystic fibrosis. Patients with cystic fibrosis have a 7% prevalence of associated liver disease and portal hypertension. These patients have been previously excluded from consideration for lung transplantation. The natural history of cystic fibrosis-associated liver disease suggests a benign and protracted course in most cases. At the University of Washington, 14 of 53 patients (26%) have undergone lung transplantation for cystic fibrosis-related respiratory failure. We report the outcome of double lung transplantation in four of these 14 patients who also had cystic fibrosis-associated liver disease and portal hypertension, all of whom were symptom free from their liver disease. All four patients are alive and well without complications 4 to 31 months after transplantation. We conclude that the presence of cystic fibrosis-associated liver disease with portal hypertension, in the setting of good synthetic function (albumin > 3.0 gm/L and normal prothrombin time), normal serum bilirubin, minimal varices, without ascites or encephalopathy, should not be an absolute contraindication to lung transplantation. We recommend that other transplantation centers also include this patient population in consideration for lung transplantation.

Alterations in chemotactic factor-induced responses of neutrophils and monocytes from chronic dialysis patients.

Chronic renal failure patients on dialysis have an increased susceptibility to infection. Previous studies have demonstrated that these patients have a decreased in vitro neutrophil (PMN) chemotactic response and a reduction in C5a receptor availability on both PMN and monocytes. This study was designed to determine if other chemotactic factor-mediated responses of PMN and monocytes from hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients are abnormal. The responses investigated included in vitro chemotaxis, superoxide generation, H2O2 production, and myeloperoxidase (MPO) release. These studies showed that PMN from HD and CAPD patients are significantly decreased in their chemotactic response to both C5a and fMLP when compared to normal controls. The response of HD patient's PMN to C5a was decreased by an average of 55.1% (p less than 0.005) and for CAPD patients by 49.7% (p less than 0.01). Similarly, chemotactic responses to fMLP were decreased by an average of 44.7% (p less than 0.005) for HD patients and 36.3% (p less than 0.02) for CAPD patients. Superoxide anion production by PMN and monocytes from HD and CAPD patients in response to C5a and fMLP was also significantly decreased compared to controls. PMN superoxide production in response to C5a was decreased by an average of 36.5% (p less than 0.001) for HD patients and 32.0% (p less than 0.001) for CAPD patients. fMLP-stimulated production of superoxide was also decreased but to a lesser degree with a mean decrease of 18.0% (p less than 0.01) for HD patients and 24.1% decrease (p less than 0.01) for CAPD patients. This decreased responsiveness was restricted to C5a- and fMLP-stimulated superoxide production since phorbol myristate acetate (PMA)-stimulated responses were comparable to controls. A similar pattern of decreased superoxide production was found with monocytes from these patients. Comparable decreases in chemotactic factor-stimulated responses were also observed in a flow cytometric assay of H2O2 production in both PMN and monocytes and an in vitro assay of MPO release from PMN. Analysis of the binding of fluorescent C5a to PMN showed a direct correlation between decreased C5a binding and decreased O2- production and MPO release. Since all of these chemotactic factor-stimulated events are involved in the inflammatory process and the killing of microorganisms, alterations in these WBC functions in dialysis patients may contribute to their increased susceptibility to infection.

C5a receptor modulation on neutrophils and monocytes from chronic hemodialysis and peritoneal dialysis patients.

Chronic renal failure patients have an increased risk for infection which may partially be due to altered chemotactic ability of their white blood cells. This study was designed to evaluate chemotactic factor and Fc receptor expression on neutrophils (PMN) and monocytes from chronic renal failure patients on hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). Analysis of these receptors was performed using flow cytometry and fluorescent chemotactic factors (C5a, f-Met-Leu-Phe-Lys [fMLPL] and casein) and heat-aggregated human IgG. Peripheral blood PMN and monocytes obtained from 14 HD patients (in the predialysis period) and 14 CAPD patients were analyzed for their ability to bind each of the fluoresceinated ligands. PMN and monocytes from both patient groups had a significant reduction in their ability to bind C5a. The average percentage (+/- s.e.m.) of PMN that bound C5a was 93.9 +/- 1.1 for the controls, 72.9 +/- 3.8 for HD patients, and 79.3 +/- 4.0 for CAPD patients. Similar results were obtained with monocytes with 69.7 +/- 1.9% for controls, 54.6 +/- 4.5% for HD patients, and 31.0 +/- 4.5% for CAPD patients. These differences in C5a binding were also reflected in the average intensity of fluorescence. There was no significant difference in the percentage or fluorescence intensity of PMN or monocytes that bound casein or aggregated IgG when either group of dialysis patients was compared to the control values. Binding of fMLPL by PMN and monocytes from the HD patients and PMN from the CAPD patients were similar to control values but the binding of fMLPL by monocytes from CAPD patients was significantly suppressed (p less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Pitfalls of bone scintigraphy in suspected hip fractures.

In a review of 2617 patients who were admitted with a suspected fractured neck of femur over a period of five years, 213 had normal or equivocal plain radiographs, and were subsequently investigated by bone scintigraphy. Normal scans were obtained in 127 (60%) cases. Of the remaining 86 cases, 82 (38%) were reported to show fractures of the proximal femur, three showed pubic ramus fractures, and one acetabular fracture was demonstrated. Review and follow-up has revealed eight false positive and two false negative scans. The various factors accounting for these errors are considered, and the clinical implications discussed. Careful analysis of accompanying plain radiographs is stressed when interpreting scintigrams.

Demonstration of specific receptors for fluoresceinated casein on human neutrophils and monocytes using flow cytometry.

Casein is chemotactic for human neutrophils (PMNs) and monocytes. The binding of fluorescein (FITC)-conjugated casein (mixture of alpha, beta, and kappa-casein) and purified alpha-casein to PMNs, monocytes, and lymphocytes was analyzed using flow cytometry. These studies demonstrate that 75-95% of PMNs and 46-85% of monocytes have membrane receptors for casein while lymphocytes lack these receptors. The binding of FITC-casein and FITC-alpha-casein was specific and was blocked only by unlabeled casein and alpha-casein, but not by ovalbumin, bovine or human serum albumin, beta-casomorphin, C5a, or formyl-methionyl-leucylphenylalanine (fMLP). The binding of FITC-casein was reversible when PMNs were stained with this fluorescent agent and subsequently incubated with unlabeled casein. Double-labeling studies of mononuclear cells using FITC-casein and the OKM1 monoclonal antibody in conjunction with a rhodamine conjugated anti-Ig second antibody demonstrate that mononuclear cells binding FITC-casein also stain with the OKM1 monoclonal antibody, indicating a specificity for monocytes.

Coronal fractures of the lateral femoral condyle.

We reviewed seven patients with coronal fractures of the lateral femoral condyle and studied the mechanism of injury and the radiological features. The influence of soft tissue attachments on the displacement and the blood supply were investigated by clinical and cadaveric studies. All three fractures which were initially undisplaced lost position early during conservative management. Internal fixation gave good results at review, and is recommended to avoid the risk of malunion and possible secondary osteoarthritis.

Calcium metabolism in blood and peritoneal lymphocytes from continuous ambulatory peritoneal dialysis patients.

OBJECTIVE: Cellular immune function in peritoneal dialysis patients has been shown to be depressed, but the mechanism of this immunosuppression has not been ascertained. Because calcium is an important mediator of lymphocyte activation, this study was designed to investigate if there was an alteration of calcium metabolism in the lymphocytes of continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN: Sixteen CAPD patients were studied at the initiation of CAPD and after two months of treatment. Twenty-three normal controls were also enrolled in the study. Cytoplasmic calcium changes were investigated in response to the mitogen phytohemagglutinin (PHA) in peripheral blood and peritoneal lymphocytes, using the intracellular calcium probe indo-1 and flow cytometry. Baseline cytoplasmic calcium levels and changes in cytoplasmic calcium in response to PHA were assessed at the initiation of CAPD and after two months of therapy. RESULTS: Peripheral lymphocytes of patients and controls had similar calcium baseline levels, but the peritoneal lymphocytes had baseline cytoplasmic calcium levels averaging 81% higher than the corresponding calcium levels of the patients' peripheral blood lymphocytes. As compared to peripheral lymphocytes, the response to PHA stimulation was significantly less in the peritoneal lymphocytes, increasing an average of only 46.8% above baseline. Peripheral blood lymphocytes of the patients responded by an average increase of 78.9% over baseline. Control cells increased an average of 66.3% over baseline. Follow-up studies done two months after the initiation of CAPD indicated there were no significant changes (as compared to month 0) that occurred in baseline or stimulated intracellular calcium concentrations. CONCLUSIONS: While the peripheral lymphocytes of CAPD patients respond adequately to PHA, the high baseline calcium levels of the peritoneal lymphocytes suggest that these cells may be in a state of chronic activation and may respond minimally to an antigenic challenge.

Characteristics of peripheral and peritoneal lymphocytes from continuous ambulatory peritoneal dialysis patients.

The role of peritoneal lymphocytes in host immunity for continuous ambulatory peritoneal dialysis (CAPD) patients is just beginning to be understood. CAPD therapy increases the proportion of peritoneal lymphocytes, most of which demonstrate signs of activation. There are decreased peritoneal T cells and increased peritoneal B cells as compared to the patients' peripheral blood. When studies examine immunophenotypes of peripheral and peritoneal lymphocytes over time, no significant changes are found. Although changes in peritoneal lymphocyte subsets occur during peritonitis episodes, there are no changes in peripheral blood lymphocytes. The purpose of this article is to provide a brief review of research that has studied lymphocytes in CAPD patients.

Lymphocyte phenotypes in infants are altered by separation of blood on density gradients.

Flow cytometry techniques for immunophenotyping have revolutionised the diagnosis and monitoring of paediatric immunological disorders. Although recent studies in adult subjects discourage the use of density gradients for cell preparation prior to phenotyping, these procedures continue to be used. The purpose of this study was to determine the effect of density gradient separation on lymphocyte phenotypes from neonates, infants, and adults as compared to whole blood determinations. Subset distributions were different with the two procedures. In all three groups, CD19+ (B cell) and CD8+ (suppressor/cytotoxic T cell) percentages were significantly lower and CD3-CD56+ (NK cell) percentages were significantly higher in the density gradient separated cells. The loss of CD8+ cells in density gradient separation was shown to be a selective event. The CD8+CD11b- (cytotoxic T) subset percentages were lower in the density gradient separated cells, while the percentages of CD8+CD11b+ (suppressor T) cells were not affected by separation procedure. Because of the selective loss of lymphocytes on density gradients, the use of a whole blood technique for immunophenotyping in paediatric subjects is recommended.

Conservative surgery for vesicocolic fistula.

Vesicocolic fistula due to diverticular disease of the colon is conventionally treated by resection of the diseased bowel and closure of the vesical defect. Three cases are described in which separation of the viscera and simple suture of the vesical and colonic defects was carried out. A greater omental graft was interposed between the rectum and bladder. Two of the patients are well 12 and 26 months postoperatively. The third patient died a year postoperatively from a complication of her diverticular disease.

Pediatric and family HIV. Psychosocial concerns across the continuum of disease.

In this article, the authors examine the spectrum of HIV disease as it affects parents and their children from the initial diagnosis through the progression of the disease. The psychosocial factors affecting access to health care, family relationships, and issues of loss are focused on. Practitioner guidelines for assisting families to deal with the psychosocial challenges presented by HIV infection are provided.

Individualizing fortification of human milk using real time human milk analysis.

OBJECTIVE: To use real-time human milk macronutrient analysis to calculate final composition following fortification. STUDY DESIGN: Preterm HM (PHM) and pooled donor human milks (DHM) were analyzed by mid-infrared spectroscopy for protein, fat and lactose. Energy content was calculated from macronutrient results. Three lactation stages were constructed. DHM was compared to PHM. Four milk sample profiles were selected to demonstrate individualized fortification results. RESULTS: Lactose was similar in PHM and DHM. Protein in PHM showed the expected decline as lactation progressed. DHM protein was significantly lower vs. PHM. Fat was highly variable and lowest in DHM. Using standard fortification protocols, not all fortified milks met targets for protein and energy. Individualized fortification resulted in milks closer to target recommendations. CONCLUSIONS: Real-time analysis of HM provides assessment of the macronutrient content of the milk and can guide fortification. Individualized protocols, based on actual milk macronutrient profiles, may need to be considered to avoid unexpected nutrient content.