Optimizing gamma-ray spectrometers for UAV-borne surveys with geophysical applications

Heavy duty unmanned aerial vehicles (UAVs) have made it possible to fly with large gamma-ray spectrometers that weigh several kilograms. Moreover, they can be purchased at an affordable price. These large UAV-borne gamma-ray detection systems are used to map the naturally occurring radionuclides ⁴⁰K, ²³⁸U, ²³²Th. Such platforms have the advantage that they can be deployed over terrain that is difficult to access, while still maintaining a high spatial resolution. In contrast to UAV-borne radioactive pollution studies, the naturally occurring radionuclides have a much lower activity and therefore require longer integration time, slower flying speed or a larger detector, in order to effectively determine the spatial radionuclide distribution. Therefore, the question arises: what is the minimum practical detector size required to successfully map ⁴⁰K, ²³⁸U and ²³²Th concentrations from UAV platforms. In this study an agricultural field has been mapped with three different scintillator-based gamma-ray spectrometers: a 2000 ml, 1000 ml, and 350 ml detector. They were mounted together on the same UAV. At a flying height of 20 m and a speed of 5.6 m s^-1 the field was mapped. The various aerial measurements were compared to each other and to the ground-based measurements. The field had a low spatial variation in the ⁴⁰K concentration (relative standard deviation (RSD) = 9%) and a larger variation for ²³⁸U and ²³²Th concentrations (RSD = 24% and 31% respectively). Radionuclide concentrations have been extracted from the survey data by Full Spectrum Analysis (FSA). Uncertainties and variances of the radionuclides have been determined by using two methods. Firstly, they are calculated directly from the FSA output and secondly they are extracted from a variogram. The latter incorporates spatial variation and was shown to provide a lower uncertainty. When using small detectors, the former approach could lead to the conclusion that the uncertainty is larger than the variance, while the variogram approach does capture the spatial variation. All three detectors were able to characterize the spatial distribution of the ²³²Th concentration. It is shown that the ²³²Th concentration is a good predictor of the sand and clay fraction of the topsoil in the field. By comparing the UAV-borne measurements to the ground-based measurements it is found that UAV-borne measurements at 20 m height are less sensitive to extreme values than ground-based measurements and they have the tendency to shift to the mean concentration of the area. The results of this study can be used to optimize the detector volume, survey height, and survey speed to maintain an acceptable accuracy for gamma-ray studies with small UAV-borne detectors.

Estimating spatially distributed SOC sequestration potentials of sustainable land management practices in Ethiopia

The sustainable land management program (SLMP) of Ethiopia aims to improve livelihoods and create resilient communities and landscape to climate change. Soil organic carbon (SOC) sequestration is one of the key co-benefits of the SLMP. The objective of this study was to estimate the spatial dynamics of SOC in 2010 and 2018 (before and after SLMP) and identify the SOC sequestration hotspots at landscape scale in four selected SLMP watersheds in the Ethiopian highlands. The specific objectives were to: 1) comparatively evaluate SOC sequestration estimation model building strategies using either a single watershed, a combined dataset from all watersheds, and leave-one-watershed-out using Random Forest (RF) model; 2) map SOC stock of 2010 and 2018 to estimate amount of SOC sequestration and potential; 3) evaluate the impacts of SLM practices on SOC in four SLMP watersheds. A total of 397 auger composite samples from the topsoil (0-20 cm depth) were collected in 2010, and the same number of samples were collected from the same locations in 2018. We used simple statistics to assess the SOC change between the two periods, and machine learning models to predict SOC stock spatially. The study showed that statistically significant variation (P < 0.05) of SOC was observed between the two years in two watersheds (Gafera and Adi Tsegora) whereas the differences were not significant in the other two watersheds (Yesir and Azugashuba). Comparative analysis of model-setups shows that a combined dataset from all the four watersheds to train and test RF outperform the other two strategies (a single watershed alone and a leave-one-watershed-out to train and test RF) during the testing dataset. Thus, this approach was used to predict SOC stock before (2010) and after (2018) land management interventions and to derive the SOC sequestration maps. We estimated the sequestrated, achievable and target level of SOC stock spatially in the four watersheds. We assessed the impact of SLM practices, specifically bunds, terraces, biological and various forms of tillage practices on SOC using partial dependency algorithms of prediction models. No tillage (NT) increased SOC in all watersheds. The combination of physical and biological interventions ("bunds + vegetations" or "terraces + vegetations") resulted in the highest SOC stock, followed by the biological intervention. The achievable SOC stock analysis showed that further SOC stock sequestration of up to 13.7 Mg C ha--1 may be possible in the Adi Tsegora, 15.8 Mg C ha-1 in Gafera, 33.2 Mg C ha-1 in Azuga suba and 34.7 Mg C ha-1 in Yesir watersheds.

Footprint and height corrections for UAV-borne gamma-ray spectrometry studies

Advancements in the development of gamma-ray spectrometers (GRS) have led to small and lightweight spectrometers that can be used under unmanned aerial vehicles (UAVs). Airborne GRS measurements are used to determine radionuclide concentrations in the ground, among which the natural occurring radionuclides ⁴⁰K, ²³⁸U, and ²³²Th. For successful applications of these GRS sensors, it is important that absolute values of concentrations can be measured. To extract these absolute radionuclide concentrations, airborne gamma-ray data has to be corrected for measurement height. However, the current analysis models are only valid for the height range of 50-250 m. The purpose of this study is to develop a procedure that correctly predicts the true radionuclide concentration in the ground when measuring in the UAV operating range of 0-40 m. An analytical model is developed to predict the radiation footprint as a function of height. This model is used as a tool to properly determine a source-detector geometry to be used in Monte-Carlo simulations of detector response at various elevations between 0 and 40 m. The analytical model predicts that the smallest achievable footprint at 10 m height lies between 22 and 91 m and between 40 and 140 m at 20 m height. By using Monte-Carlo simulations it is shown that the analytical model correctly predicts the reduction in full energy peak gamma-rays, but does not predict the Compton continuum of a spectrum as a function of height. Therefore, Monte-Carlo simulations should be used to predict the shape and intensity of gamma-ray spectra as a function of height. A finite set of Monte-Carlo simulations at intervals of 5 m were used for the analysis of GRS measurements at heights up to 35 m. The resulting radionuclide concentrations at every height agree with the radionuclide concentration measured on the ground.

Outcome after Hybrid Outflow Interventions for Chronic Limb-threatening Ischemia

BACKGROUND AND AIMS

Because chronic limb-threatening ischemia (CLTI) is often associated with multilevel arterial disease, it usually requires revascularization at different sites of the limb vasculature. We aim to assess the outcome of the hybrid interventions including open surgical revascularization together with outflow segment percutaneous transluminal angioplasty (PTA) in patients with chronic limb-threatening ischemia.

MATERIAL AND METHODS

This study included all hybrid outflow-PTA interventions (n = 80) on patients suffering from CLTI performed in Helsinki University Hospital between 2003 and 2015. Follow-up ended on 31 December 2019. Patient data were prospectively collected into our vascular registry and scrutinized retrospectively. Thirty-one patients (39%) suffered from rest pain (Rutherford category IV) and 49 patients (61%) had ischemic ulcers (Rutherford category V-VI). The most common open surgical procedure was femoral endarterectomy (n = 63, 79%) and the most common endovascular procedure was superficial femoral artery percutaneous transluminal angioplasty (n = 65, 81%). Mean follow-up time was 56 months (range: 4 days-183 months).

RESULTS

Limb salvage was at 30 days-92%, at 1 year-91%, and at 5 and 10 years-86%. Survival and amputation-free survival were at 30 days-93% and 86%, at 1 year-80% and 76%, at 5 years-51% and 48%, and at 10 years-21% and 21%. Wound healing at 3, 6, and 12 months was 48%, 71%, and 87%. Freedom from target lesion revascularization was at 30 days-97%, at 1 year-88%, at 5 years-72%, and at 10 years-66%.

CONCLUSION

Hybrid outflow revascularization is an important tool in the vascular surgeon's armamentarium for treatment of patients with multilevel arterial disease causing chronic limb-threatening ischemia.

Predictions of Cu, Zn, and Cd Concentrations in Soil Using Portable X-Ray Fluorescence Measurements

Portable X-ray fluorescence (PXRF) measurements on 1520 soil samples were used to create national prediction models for copper (Cu), zinc (Zn), and cadmium (Cd) concentrations in agricultural soil. The models were validated at both national and farm scales. Multiple linear regression (MLR), random forest (RF), and multivariate adaptive regression spline (MARS) models were created and compared. National scale cross-validation of the models gave the following R² values for predictions of Cu (R² = 0.63), Zn (R² = 0.92), and Cd (R² = 0.70) concentrations. Independent validation at the farm scale revealed that Zn predictions were relatively successful regardless of the model used (R² > 0.90), showing that a simple MLR model can be sufficient for certain predictions. However, predictions at the farm scale revealed that the non-linear models, especially MARS, were more accurate than MLR for Cu (R² = 0.94) and Cd (R² = 0.80). These results show that multivariate modelling can compensate for some of the shortcomings of the PXRF device (e.g., high limits of detection for certain elements and some elements not being directly measurable), making PXRF sensors capable of predicting elemental concentrations in soil at comparable levels of accuracy to conventional laboratory analyses.

Herd and environmental determinants of reproductive performance in Swedish dairy herds, 2001-2009

This was a retrospective cohort study of Swedish dairy herds. Summary measures of production and reproductive performance, details of soil, moss mineral concentrations, and temperature and rainfall measurements at each herd location were available for the period September 2001 to August 2009. A Bayesian mixed-effects regression model including spatial and non-spatial heterogeneity terms was developed to quantify associations between hypothesised explanatory variables and mean herd breeding interval, defined as the difference between mean calving to last service interval and mean calving to first service interval for each fiscal year. Mean herd breeding intervals were shorter in herds with greater than 80% Swedish Red Cattle, herds with lower mean age at first calving, herds comprised of older cows and in larger herds. None of the soil composition or moss mineral concentration estimates were associated with mean herd breeding interval and the effect of temperature and rainfall on mean herd breeding interval was small. We conclude that environmental conditions (soil composition, moss mineral concentrations, environmental temperature and rainfall) had relatively minor effects on dairy herd reproductive performance in Sweden between 2001 and 2009.

Risk assessment of high concentrations of molybdenum in forage

Molybdenum is toxic to ruminants when present in high levels in forage, causing physiological copper deficiency. A critical level for ruminants is 3-10 mg Mo kg^-1 dry matter. The average Mo level varies considerably between different arable soils, depending mainly on soil parent material. This study investigated the possibility of using various existing sources of geospatial information (geophysical, biogeochemical and soil chemical) to develop a geography-based risk assessment system. Forage samples (n = 173) were collected in 2006-2007. Three types of national geoscientific datasets were tested: (1) SEPA topsoil, comprising data from arable land within the Swedish environmental monitoring programme; (2) SGU biogeochemical, containing data from aquatic plant root material collected in small streams; and (3) SGU geophysical, consisting of data from airborne gamma-ray scanning. The digital postcode area map was used for geocoding, with Mo concentrations in forage assigned to arable parts of the corresponding postcode area. By combining this with the three national geoscientific databases, it was possible to construct a risk map using fuzzy classification depicting High-risk, Intermediate-risk, Low-risk and Very-low-risk areas. The map was validated using 42 randomly selected samples. All samples but one with Mo > 3 mg kg^-1 were found in postcode areas designated High risk. Thus, the risk map developed seems to be useful as a decision support system on where standard forage analyses need to be supplemented with Mo analyses.

Platelet-induced growth of human fibroblasts is associated with an increased expression of 5-lipoxygenase

Proliferation of fibroblasts is vital for adequate wound healing but is probably also involved in different hyperproliferative disorders such as atherosclerosis and cancer. The regeneration of tissue usually starts with coagulation, involving release of mitogenic and inflammatory factors from activated platelets. This study focuses on the role of eicosanoids in the proliferative effects of platelets on human fibroblasts. We show that the phospholipase A2 inhibitor 7,7-dimethyl-5,8-eicosadienoic acid (DMDA), the combined cyclooxygenase (COX) and lipoxygenase (LOX) inhibitor 5,8,11,14-eicosatetraynoic acid (ETYA) and the LOX inhibitor 5,8,11-eicosatriynoic acid (ETI) block the platelet-induced proliferation of serum starved subconfluent human fibroblasts. Anti-proliferative effects were also obtained by specific inhibition of 5-LOX with 5,6-dehydro arachidonic acid (5,6-dAA), whereas the 12-LOX inhibitor cinnamyl-3,4-dihydroxy-α-cyanocinnamate (CDC) did not affect the platelet-stimulated growth of fibroblasts. The expression of 5-LOX was analyzed by reverse-transcriptase-mediated PCR (RT-PCR), Western blotting and HPLC. 5-LOX message and protein was detected in fibroblasts but not in platelets. Incubation with platelets markedly increased, already after one hour, the expression of 5-LOX in the fibroblast culture. The increased 5-LOX activity was associated with an elevated level of the 5-LOX metabolite 5-hydroxyeicosatetraenoic acid (5-HETE) reaching its maximum after 1–2 hours of co-incubation of fibroblasts and platelets. The 5-HETE production was reduced by the inhibitors DMDA, ETYA and ETI. In conclusion, this study suggests that platelet-stimulated proliferation of fibroblasts is mediated by an increased 5-LOX activity, which supports recent findings indicating a crucial role for this enzyme in proliferative disorders such as atherosclerosis.

In vivo imaging of Lyme arthritis in mice by [18F]fluorodeoxyglucose positron emission tomography/computed tomography

OBJECTIVE

Lyme borreliosis (LB) is a tick-borne infectious disease caused by Borrelia burgdorferi spirochaetes, which are able to disseminate from the tick-bite site to distant organs. Mouse models are widely used to study LB and especially Lyme arthritis (LA), but only a few whole-animal in vivo imaging studies on the pathogenesis of B. burgdorferi infection in mice have been published so far. The existing imaging techniques have their drawbacks and, therefore, novel tools to complement the array of available LB imaging methodologies are needed.

METHOD

The applicability of positron emission tomography combined with computed tomography (PET/CT) imaging was evaluated as a method to monitor LB and especially LA in the C3H/HeN mouse model infected with wild-type B. burgdorferi N40 bacteria. The imaging results were compared with the traditional LA analysis methods, such as tibiotarsal joint swelling and histopathological assessment of joint inflammation.

RESULTS

PET/CT imaging provided high-resolution images with quantitative information on the spatial and temporal distribution of the [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) tracer in B. burgdorferi-infected mice. The [¹⁸F]FDG accumulated in the affected joints and activated lymph nodes of infected mice, while the tracer signal could not be visualized in these organs in uninfected control animals. Importantly, in vivo PET/CT imaging data were in agreement with the histopathological scoring of inflammation of mouse joints.

CONCLUSION

PET/CT imaging with [¹⁸F]FDG is a reliable method to longitudinally monitor the development and progression of B. burgdorferi infection-induced inflammation in vivo in mouse joints.

Predicting deoxynivalenol in oats under conditions representing Scandinavian production regions

Deoxynivalenol (DON) in cereals, produced by Fusarium fungi, cause poisoning in humans and animals. Fusarium infections in cereals are favoured by humid conditions. Host species are susceptible mainly during the anthesis stage. Infections are also positively correlated with a regional history of Fusarium infections, frequent cereal production and non-tillage field management practices. Here, previously developed process-based models based on relative air humidity, rain and temperature conditions, Fusarium sporulation, host phenology and mycelium growth in host tissue were adapted and tested on oats. Model outputs were used to calculate risk indices. Statistical multivariate models, where independent variables were constructed from weather data, were also developed. Regressions of the risk indices obtained against DON concentrations in field experiments on oats in Sweden and Norway 2012-14 had coefficient of determination values (R²) between 0.84 and 0.88. Regressions of the same indices against DON concentrations in oat samples averaged for 11 × 11 km grids in farmers' fields in Sweden 2012-14 resulted in R² values between 0.27 and 0.41 for randomly selected grids and between 0.31 and 0.62 for grids with average DON concentration above 1000 μg kg^-1 grain in the previous year. When data from all three years were evaluated together, a cross-validated statistical partial least squares model resulted in R² = 0.70 and a standard error of cross-validation (SECV) = 522 μg kg^-1 grain for the period 1 April-28 August in the construction of independent variables and R² = 0.54 and SECV = 647 μg kg^-1 grain for 1 April-23 June. Factors that were not accounted for in this study probably explain large parts of the variation in DON among samples and make further model development necessary before these models can be used practically. DON prediction in oats could potentially be improved by combining weather-based risk index outputs with agronomic factors.

Performance Evaluation of Proximal Sensors for Soil Assessment in Smallholder Farms in Embu County, Kenya

Four proximal soil sensors were tested at four smallholder farms in Embu County, Kenya: a portable X-ray fluorescence sensor (PXRF), a mobile phone application for soil color determination by photography, a dual-depth electromagnetic induction (EMI) sensor, and a LED-based soil optical reflectance sensor. Measurements were made at 32–43 locations at each site. Topsoil samples were analyzed for plant-available nutrients (N, P, K, Mg, Ca, S, B, Mn, Zn, Cu, and Fe), pH, total nitrogen (TN) and total carbon (TC), soil texture, cation exchange capacity (CEC), and exchangeable aluminum (Al). Multivariate prediction models of each of the lab-analyzed soil properties were parameterized for 576 sensor-variable combinations. Prediction models for K, N, Ca and S, B, Zn, Mn, Fe, TC, Al, and CEC met the setup criteria for functional, robust, and accurate models. The PXRF sensor was the sensor most often included in successful models. We concluded that the combination of a PXRF and a portable soil reflectance sensor is a promising combination of handheld soil sensors for the development of in situ soil assessments as a field-based alternative or complement to laboratory measurements.

Multiple sclerosis: expression of C D1a and production of IL-12 p70 and IFN-γ by blood mononuclear cells in patients on combination therapy with IFN-β and glatiramer acetate compared to monotherapy with IFN-β

Current therapy of multiple sclerosis (MS) with interferon-beta (IFN-b) or glatiramer acetate (GA) has modest effects on the course of MS. Both compounds affect several immune variables, like expression of cell surface molecules and cytokine levels. Here we compared untreated MS, therapy with IFN-b alone and combined with GA, and healthy controls (HC), regarding expression on HLA -DR+ blood mononuclear cells (MNC) of C D1a that is a cell surface molecule with capacity to present glycolipids to T cells, and of C D80 and C D86 which are costimulatory molecules that activate Th1 and Th2 responses. C ytokine production by MNC was also measured. Flow cytometry and ELISA were used. C ross-sectional comparisons revealed that untreated MS patients had higher C D1a+ HLA -DR+ MNC and lower IL-10 production compared to patients treated with IFN-b or IFN-b+G A or HC. Untreated MS patients also had higher spontaneous IFN-g and IL-12p70 production compared to MS patients treated with IFN-b+G A or HC, but not when compared to MS patients on monotherapy with IFN-b. Low C D1a+ HLA -DR+ MNC and low spontaneous production of IL-12p70 and IFN-g were more pronounced in patients treated with IFN-b+G A than with IFN-b alone. In order to clarify whether these changes reflect disease activity or treatment effects, we performed a follow up study. Nineteen MS patients with disease progression, despite monotherapy with IFN-b for more than one year, were re-examined after one to three and four to six months of treatment with IFN-b+G A. This combination therapy was associated with normalization of C D1a+ HLA -DR+ MNC, IL-12p70 and IFN-g. It remains to be shown whether these immunological changes imply a clinical benefit. Follow up studies of immune variables versus clinical effects during combined therapy of MS with IFN-b+G A are ongoing.

Multiple sclerosis-associated retrovirus and optic neuritis

One prognostic factor for early multiple sclerosis (MS) patients to develop a definite MS may be the presence of the MS-associated retrovirus (MSRV) in the cerebrospinal fluid (CSF). We designed a specific study on a cohort of optic neuritis (ON) patients to evaluate the MSRV-dependent conversion to MS relative to the prediction conferred by magnetic resonance imaging (MRI) and CSF abnormalities. At follow-up, 33.3% MSRV+ and 0% MSRV− ON patients developed MS ( P=0.03). The prediction value is lower than that given by CSF and MRI abnormalities (42.3%). This intriguing finding is discussed in the light of the abundant discrepancies observed in the MSRV literature.

Cerebrospinal fluid levels of brain specific proteins in optic neuritis

This study evaluates levels of cerebrospinal fluid (C SF) brain-specific proteins (BSP) in subjects with optic neuritis (O N) who are at high risk of progression to multiple sclerosis (MS). Forty-one subjects had acute O N and 17 subjects with other neurological diseases (OND) served as controls. Twenty-o ne subjects with O N had white matter lesions on magnetic resonance imaging (MRI) and intrathecal synthesis of oligoclonal IgG bands (OB) consistent with being at high risk of progression to MS; eight of whom later were diagnosed with clinically definite MS (C DMS). Levels of S100B, ferritin and two neurofilament heavy chain phosphoforms (NfHSMI34 and NfHSMI35) were analysed using ELISA technique. A putative index of ‘axonal health’ was expressed as a ratio of NfHSMI34 to NfHSMI35. NfHSMI34 and the NfHSMI34:SMI35 were significantly elevated in subjects with O N compared to controls. No significant differences in levels of C SF BSP were seen between O N subjects with C DMS plus those at high risk of progression to MS and O N subjects with normal MRI and negative C SF analysis. In conclusion, there is evidence of axonal damage in subjects who present with O N, which is independent of the diagnosis of C DMS.

Cdc20 and securin overexpression predict short-term breast cancer survival

BACKGROUND

Cdc20 is an essential component of cell division and responsible for anaphase initiation regulated by securin degradation. Cdc20 function is strongly regulated by the spindle assembly checkpoint to ensure the timely separation of sister chromatids and integrity of the genome. We present the first results on Cdc20 in a large clinical breast cancer material.

METHODS

The study was based on 445 breast cancer patients with up to 20 years of follow-up (mean 10.0 years). DNA content was determined by image cytometry on cell imprints, and Cdc20 and securin immunohistochemistry on tissue microarrays of breast cancer tissue.

RESULTS

In our results, high Cdc20 and securin expression was associated with aneuploid DNA content. In prognostic analyses, high Cdc20 immunoexpression alone and in combination with high securin immunoexpression indicated aggressive course of disease and up to 6.8-fold (P<0.001) risk of breast cancer death. Particularly, high Cdc20 and securin immunoexpression identified a patient subgroup with extremely short, on average 2.4 years, breast cancer survival and triple-negative breast cancer (TNBC) subtype.

CONCLUSIONS

We report for the first time the association of high Cdc20 and securin immunoexpression with extremely poor outcome of breast cancer patients. Our experience indicates that Cdc20 and securin are promising candidates for clinical applications in breast cancer prognostication, especially in the challenging prognostic decisions of TNBC.

Casein hydrolysate diet controls intestinal T cell activation, free radical production and microbial colonisation in NOD mice

AIMS/HYPOTHESIS

Dietary and microbial factors and the gut immune system are important in autoimmune diabetes. We evaluated inflammatory activity in the whole gut in prediabetic NOD mice using ex vivo imaging of reactive oxygen and nitrogen species (RONS), and correlated this with the above-mentioned factors.

METHODS

NOD mice were fed a normal diet or an anti-diabetogenic casein hydrolysate (CH) diet. RONS activity was detected by chemiluminescence imaging of the whole gut. Proinflammatory and T cell cytokines were studied in the gut and islets, and dietary effects on gut microbiota and short-chain fatty acids were determined.

RESULTS

Prediabetic NOD mice displayed high RONS activity in the epithelial cells of the distal small intestine, in conjunction with a proinflammatory cytokine profile. RONS production was effectively reduced by the CH diet, which also controlled (1) the expression of proinflammatory cytokines and colonisation-dependent RegIIIγ (also known as Reg3g) in ileum; (2) intestinal T cell activation; and (3) islet cytokines. The CH diet diminished microbial colonisation, increased the Bacteroidetes:Firmicutes ratio, and reduced lactic acid and butyric acid production in the gut.

CONCLUSIONS/INTERPRETATION

Epithelial RONS production and proinflammatory T cell activation appears in the ileum of NOD mice after weaning to normal laboratory chow, but not after weaning to an anti-diabetogenic CH diet. Our data suggest a link between dietary factors, microbial colonisation and mucosal immune activation in NOD mice.

The quality of the outdoor environment influences childrens health -- a cross-sectional study of preschools

AIM

To test how the quality of the outdoor environment of child day care centres (DCCs) influences children's health.

METHODS

The environment was assessed using the Outdoor Play Environmental Categories (OPEC) tool, time spent outdoors and physical activity as measured by pedometer. 172/253 (68%) of children aged 3.0-5.9 from nine DCCs participated in Southern Sweden. Health data collected were body mass index, waist circumference, saliva cortisol, length of night sleep during study, and symptoms and well-being which were scored (1-week diary - 121 parent responders). Also, parent-rated well-being and health of their child were scored (questionnaire, 132 parent responders). MANOVA, ANOVA and principal component analyses were performed to identify impacts of the outdoor environment on health.

RESULTS

High-quality outdoor environment at DCCs is associated with several health aspects in children such as leaner body, longer night sleep, better well-being and higher mid-morning saliva cortisol levels.

CONCLUSION

The quality of the outdoor environment at DCCs influenced the health and well-being of preschool children and should be given more attention among health care professionals and community planners.

End-stage renal disease and critical limb ischemia: a deadly combination?

OBJECTIVES

This study was planned to evaluate the prognostic impact of end-stage renal disease (ESRD) in patients with critical leg ischemia (CLI) undergoing infrainguinal revascularization.

MATERIALS AND METHODS

1425 patients who underwent infrainguinal revascularization for CLI were the subjects of the present analysis. Ninety-five patients had ESRD (eGFR < 15 ml/min/m²), and of them 66 (70%) underwent percutaneous transluminal angioplasty and 29 (30%) underwent bypass surgery.

RESULTS

ESRD patients had significantly lower overall survival (at 3-year, 27.1% vs. 59.7%, p < 0.0001), leg salvage (at 3-year, 57.7% vs. 83.0%, p < 0.0001), and amputation free survival (at 3-year, 16.2% vs. 52.9%, p < 0.0001) than patients with no or less severe renal failure. The difference in survival was even greater between 86 one-to-one propensity matched pairs (at 3-year, 23.1% vs. 67.3%, p < 0.0001). ESRD was an independent predictor of all-cause mortality (RR 2.46, 95%CI 1.85-3.26). Logistic regression showed that age ≥ 75 years was the only independent predictor of 1-year all-cause mortality (OR 4.92, 95%CI 1.32-18.36). Classification and regression tree analysis showed that age ≥ 75 years and, among younger patients, bypass surgery for leg ulcer and gangrene were associated with significantly higher 1-year mortality

CONCLUSIONS

Lower limb revascularization in patients with CLI and end-stage renal failure is associated with favourable leg salvage. However, these patients have a very poor survival and this may jeopardize any attempt of revascularization. Further studies are needed to identify ESRD patients with acceptable life expectancy and who may benefit from lower limb revascularization.

Tile drain losses of nitrogen and phosphorus from fields under integrated and organic crop rotations. A four-year study on a clay soil in southwest Sweden

In order to explore the influence of site-specific soil properties on nitrogen (N) and phosphorus (P) losses between individual fields and crop sequences, 16 drained fields with clay soils were investigated in a four-year study. Mean total N (TN) loss was 6.6-11.1 from a conventional, 14.3-21.5 from an organic and 13.1-23.9 kg ha(-1) year(-1) from an integrated cropping system across a 4 year period, with 75% in nitrate form (NO(3)-N). Mean total P (TP) loss was 0.96-3.03, 0.99-4.63 and 0.76-2.67 kg ha(-1) year(-1), from the three systems respectively during the same period, with 25% in dissolved reactive form (DRP). Median N efficiency was calculated to be 70% including gains from estimated N fixation. According to principal component factor (PCA) analysis, field characteristics and cropping system were generally more important for losses of N and P than year. Accumulation of soil mineral N in the autumn and (estimated) N fixation was important for N leaching. No P fertilisers were used at the site in either cropping system. Total P concentration in drainage water from each of the fields was marginally significantly (p<0.05) correlated to TP concentration in the topsoil (r=0.52), measured in hydrochloric acid extract (P-HCl). Mean DRP concentrations were significantly (p<0.01) correlated to degree of P saturation (DPS-AL) and soil carbon (C) content in the topsoil (r=0.63). Good establishment of a crop with efficient nutrient uptake and good soil structure was general preconditions for low nutrient leaching. Incorporation of ley by tillage operations in the summer before autumn crop establishment and repeated operations in autumn as well, increased N leaching. Crop management in sequences with leguminous crops needs to be considered carefully when designing cropping systems high efficiency in N utilisation and low environmental impact.

Angiosome Theory: Fact or Fiction?

The angiosome concept delineates the human body into three-dimensional blocks of tissue fed by specific arterial and venous sources named “angiosomes.” Adjacent angiosomes are connected by a vast compensatory collateral web, or “choke vessels.” This concept may provide new information applicable to improving targeted revascularization of ischemic tissue lesions.

A few dedicated studies available seem to favor this strategy, as encouraging ulcer healing and limb preservation are reported in connection with both bypass and endovascular techniques based on these principles.

The theory on the angiosome model of revascularization (AMV) may help the clinician to better refine vessel selection, vascular access, and specific strategies in the revascularization of critically ischemic legs with tissue lesions. Specific applications of angiosome-guided revascularization were recently suggested for patients with diabetes or renal insufficiency, with ischemic tissue lesions of the lower limb, and extended large- and medium-size collateral network decay. For these cases, the concept may allow deliberate arterial reconstruction following individual wound topographies in specific ischemic areas, although deprived from “rescue-vessel” supply. The AMV theory may contribute to a shift in common reperfusion options.

However, the data available is suggestive and does not provide strong evidence as factors such as case mix and the severity of ischemia are unsatisfactorily controlled.

At present, the evidence is scarce as to the effect of the severity of the arterial disease. In all comparisons, the groups treated are likely to be dissimilar and mismatched. The angiosome concept is postulated to be valid especially in diabetics, whose ischemic lesions tend to heal worse than those of non-diabetics.

The role of chronic kidney disease as a predictor of outcome after revascularisation of the ulcerated diabetic foot

AIMS/HYPOTHESIS

The aim of the study was to stratify the risk of diabetic patients with leg ulcer or gangrene undergoing infrainguinal revascularisation for critical limb ischaemia.

METHODS

The study cohort included 732 revascularisation procedures performed in 597 diabetic patients with ulcer or gangrene. Logistic regression and CART analysis were used for identification of predictors of 1-year outcome.

RESULTS

Logistic regression showed that chronic kidney disease (CKD) class (OR 1.38, 95% CI 1.16, 1.65) was an independent predictor of 1-year leg salvage (area under the receiver operating characteristic [ROC] curve 0.60, 95% CI 0.54, 0.65). The terminal nodes of the CART for 1-year leg salvage were CKD classes 4-5, the level (infrapopliteal vs femoropopliteal revascularisation), type of revascularisation (bypass surgery vs percutaneous transluminal angioplasty) and gangrene (area under the ROC curve 0.62, 95% CI 0.57, 0.68). Logistic regression showed that pulmonary disease (OR 1.76, 95% CI 1.11, 2.78), CKD class (OR 1.43, 95% CI 1.24, 1.65), foot gangrene (OR 1.76, 95% CI 1.21, 2.60) and patient age (OR 1.02, 95% CI 1.01, 1.04) were independent predictors of 1-year amputation-free survival (area under the ROC curve 0.65, 95% CI 0.60, 0.69). The terminal nodes of the CART for 1-year amputation-free survival were CKD classes 3-5, patient's age of ≥ 75 years and foot gangrene (area under the ROC curve 0.64, 95% CI 0.60, 0.68).

CONCLUSIONS/INTERPRETATION

CKD is a formidable risk factor for poor intermediate outcome after infrainguinal revascularisation in diabetic patients with foot ulcer or gangrene. CART analysis indicates that foot gangrene is also a significant risk factor for adverse outcome.

Spatial distribution of ammonia-oxidizing bacteria and archaea across a 44-hectare farm related to ecosystem functioning

Characterization of spatial patterns of functional microbial communities could facilitate the understanding of the relationships between the ecology of microbial communities, the biogeochemical processes they perform and the corresponding ecosystem functions. Because of the important role the ammonia-oxidizing bacteria (AOB) and archaea (AOA) have in nitrogen cycling and nitrate leaching, we explored the spatial distribution of their activity, abundance and community composition across a 44-ha large farm divided into an organic and an integrated farming system. The spatial patterns were mapped by geostatistical modeling and correlations to soil properties and ecosystem functioning in terms of nitrate leaching were determined. All measured community components for both AOB and AOA exhibited spatial patterns at the hectare scale. The patchy patterns of community structures did not reflect the farming systems, but the AOB community was weakly related to differences in soil pH and moisture, whereas the AOA community to differences in soil pH and clay content. Soil properties related differently to the size of the communities, with soil organic carbon and total nitrogen correlating positively to AOB abundance, while clay content and pH showed a negative correlation to AOA abundance. Contrasting spatial patterns were observed for the abundance distributions of the two groups indicating that the AOB and AOA may occupy different niches in agro-ecosystems. In addition, the two communities correlated differently to community and ecosystem functions. Our results suggest that the AOA, not the AOB, were contributing to nitrate leaching at the site by providing substrate for the nitrite oxidizers.

Infrainguinal percutaneous transluminal angioplasty or bypass surgery in patients aged 80 years and older with critical leg ischaemia

Background

Infrainguinal revascularization for critical leg ischaemia (CLI) in patients aged 80 years and over is associated with increased operative risk. The aim was to compare the results of percutaneous transluminal angioplasty (PTA) and bypass surgery in these patients.

Methods

Some 584 consecutive patients aged at least 80 years treated with either PTA (277) or bypass surgery (307) for CLI between 2000 and 2007 were included in this study.

Results

After 2 years PTA achieved better results than bypass surgery (leg salvage: 85·4 versus 78·7 per cent, P = 0·039; survival: 57·7 versus 52·3 per cent, P = 0·014; amputation-free survival (AFS): 53·0 versus 44·9 per cent, P = 0·005). Cox regression analysis showed that increased age (relative risk (RR) 1·05, 95 per cent confidence interval 1·02 to 1·08), decreased estimated glomerular filtration rate (RR 0·99, 0·99 to 1·00), diabetes (RR 1·30, 1·04 to 1·62), coronary artery disease (RR 1·36, 1·05 to 1·75) and bypass surgery (RR 1·55, 1·24 to 1·93) were associated with decreased AFS. In 95 propensity score-matched pairs, leg salvage at 2 years (88 versus 75 per cent; P = 0·010) and AFS (53 versus 45 per cent; P = 0·033) were significantly better after PTA. Classification and regression tree analysis suggested that PTA was associated with better 1-year AFS, especially in patients with coronary artery disease (63·8 versus 48·9 per cent; P = 0·008).

Conclusion

When feasible, a strategy of PTA first appears to achieve better results than infrainguinal bypass surgery in patients aged 80 years and older.

High Leg Salvage Rate after Infrainguinal Bypass Surgery for Ischemic Tissue Loss (Fontaine IV) is Compromised by the Short Life Expectancy

Background and Aims:

Most studies analysing the prognosis of infrainguinal bypass surgery (IBS) in patients with critical leg ischemia (CLI) have combined the outcome of patients with rest pain and tissue loss. The aim of the present study was to evaluate amputation-free survival (AFS) after IBS in patients with the most advanced form of peripheral arterial disease, CLI with tissue loss (Fontaine IV), and to analyse the risk factors for an adverse outcome.

Patients and Methods:

636 patients with CLI and tissue loss who underwent unilateral IBS between January 2000 and December 2006 at our institution were included in this retrospective study.

Results:

At one year, the leg salvage, survival and amputation-free survival rates were 83%, 71% and 55%, respectively, and at five years 76%, 38% and 30%, respectively. In univariate analysis, diabetes was associated with decreased AFS. In multivariate analysis, age, coronary artery disease, chronic pulmonary disease, gangrene and renal insufficiency were independent risk factors for decreased AFS.

Conclusion:

Infrainguinal bypass grafting results in a high rate of leg salvage. Amputation-free survival was low during the follow-up due to the high mortality of patients with CLI and tissue loss. Several co-morbidities of the CLI patients were associated with decreased amputation-free survival.

Influence of input uncertainty on prediction of within-field pesticide leaching risks

Previous research has suggested that pesticide losses at the field scale can be dominated by a small proportion of the field area. The objective of this study was to investigate whether site-specific applications (i.e. avoiding high-risk areas) at the field scale can contribute to a reduction of pesticide leaching despite uncertainty in the underlying model-based leaching risk map. Using a meta-model of the dual-permeability model MACRO, the annual average pesticide leaching concentrations were estimated for 162 sample sites on a 47 ha field. The procedure was repeated for different scenarios describing different patterns of spatial variation of degradation half-lives and the partition coefficient to soil organic carbon. To account for interpolation uncertainty, maps of predicted pesticide leaching risk were produced by the method of sequential Gaussian simulation. The results of the case study show that larger reductions of predicted leaching were achieved by site-specific application than by that of a comparable uniform dose reduction. Hence, site-specific-applications may be a feasible method to reduce pesticide leaching at the field-scale providing that the model approach gives reasonable estimates of the spatial pattern of pesticide leaching.

Redox-signaling transmitted in trans to neighboring cells by melanoma-derived TNF-containing exosomes

Hydrogen peroxide is known to be involved in redox signaling pathways that regulate normal processes and disease progression, including cytokine signaling, oxidative stress, and cancer. In studies on immune surveillance against cancer, hydrogen peroxide was found to disrupt cytotoxic T-cell function, thus contributing to tumor escape. In this study, secretion of TNF-containing vesicles of rab9+ endosomal origin, termed exosomes, was investigated using GFP-TNF constructs. We observed a polarized intracellular trafficking and apical secretion of TNF-positive nanovesicles. Cell-to-cell transfer of TNF was observed in exosomes in real-time microscopy, occurring separate from the melanin/melanosome compartment. Exosomes were prepared by ultracentrifugation or immunoisolation on anti-beta2-microglobulin magnetic beads. TNF as well as TNF receptors 1 and 2 were present in the exosomes as determined by Western blot, flow cytometry, and deconvolution microscopy. The functional significance of melanoma-derived exosomes was established by their signaling competence with ability to generate significantly higher ROS levels in T cells compared with sham exosomes (P=0.0006). In conclusion, we report here, for the first time, that TNF is found in tumor cell-derived exosomes and that these exosomes transmit redox signaling in trans to neighboring cells. The results are of importance for a better understanding of tumor escape mechanisms.

Gender equality in the work of local research ethics committees in Europe: a study of practice in five countries

BACKGROUND

Funding organisations and research ethics committees (RECs) should play a part in strengthening attention to gender equality in clinical research. In the research policy of European Union (EU), funding measures have been taken to realise this, but such measures are lacking in the EU policy regarding RECs.

OBJECTIVE

To explore how RECs in Austria, Germany, Ireland, The Netherlands and Sweden deal with gender equality issues by asking two questions: (1) Do existing procedures promote representation of women and gender expertise in the committee? (2) How are sex and gender issues dealt with in protocol evaluation?

METHODS

Two RECs were selected from each country. Data were obtained through interviews with key informants and content analysis of relevant documents (regulations, guidelines and review tools in use in 2003).

RESULTS

All countries have rules (mostly informal) to ensure the presence of women on RECs; gender expertise is not required. Drug study protocols are carefully evaluated, sometimes on a formal basis, as regards the inclusion of women of childbearing age. The reason for excluding either one of the sexes or including specific groups of women or making a gender-specific risk-benefit analysis are investigated by some RECs. Such measures are, however, neither defined in the regulations nor integrated in review tools.

CONCLUSIONS

The RECs investigated in five European member states are found to pay limited attention to gender equality in their working methods and, in particular in protocol evaluation. Policy and regulations of EU are needed to strengthen attention to gender equality in the work of RECs.

Peroxisome proliferator activated receptor gamma activity is low in mature primary human visceral adipocytes

AIMS/HYPOTHESIS

The amount of visceral fat mass strongly relates to insulin resistance in humans. The transcription factor peroxisome proliferator activated receptor gamma (PPARG) is abundant in adipocytes and regulates genes of importance for insulin sensitivity. Our objective was to study PPARG activity in human visceral and subcutaneous adipocytes and to compare this with the most common model for human disease, the mouse.

MATERIALS AND METHODS

We transfected primary human adipocytes with a plasmid encoding firefly luciferase controlled by PPARG response element (PPRE) from the acyl-CoA-oxidase gene and measured PPRE activity by emission of light.

RESULTS

We found that PPRE activity was 6.6-fold higher (median) in adipocytes from subcutaneous than from omental fat from the same subjects (n = 23). The activity was also 6.2-fold higher in subcutaneous than in intra-abdominal fat cells when we used a PPARG ligand-binding domain-GAL4 fusion protein as reporter, demonstrating that the difference in PPRE activity was due to different levels of activity of the PPARG receptor in the two fat depots. Stimulation with 5 micromol/l rosiglitazone did not induce a PPRE activity in visceral adipocytes that was as high as basal levels in subcutaneous adipocytes. Interestingly, in mice of two different strains the PPRE activity was similar in visceral and subcutaneous fat cells.

CONCLUSIONS/INTERPRETATION

We found considerably lower PPARG activity in visceral than in subcutaneous primary human adipocytes. Further studies of the molecular mechanisms behind this difference could lead to development of drugs that target the adverse effects of visceral obesity.

Platelet-induced growth of human fibroblasts is associated with an increased expression of 5-lipoxygenase

Proliferation of fibroblasts is vital for adequate wound healing but is probably also involved in different hyperproliferative disorders such as atherosclerosis and cancer. The regeneration of tissue usually starts with coagulation, involving release of mitogenic and inflammatory factors from activated platelets. This study focuses on the role of eicosanoids in the proliferative effects of platelets on human fibroblasts. We show that the phospholipase A (2) inhibitor 7,7-dimethyl-5,8-eicosadienoic acid (DMDA), the combined cyclooxygenase (COX) and lipoxygenase (LOX) inhibitor 5,8,11,14-eicosatetraynoic acid (ETYA) and the LOX inhibitor 5,8,11-eicosatriynoic acid (ETI) block the platelet-induced proliferation of serum starved subconfluent human fibroblasts. Anti-proliferative effects were also obtained by specific inhibition of 5-LOX with 5,6-dehydro arachidonic acid (5,6-dAA), whereas the 12-LOX inhibitor cinnamyl-3,4-dihydroxy- a -cyanocinnamate (CDC) did not affect the platelet-stimulated growth of fibroblasts. The expression of 5-LOX was analyzed by reverse-transcriptase-mediated PCR (RT-PCR), Western blotting and HPLC. 5-LOX message and protein was detected in fibroblasts but not in platelets. Incubation with platelets markedly increased, already after one hour, the expression of 5-LOX in the fibroblast culture. The increased 5-LOX activity was associated with an elevated level of the 5-LOX metabolite 5-hydroxyeicosatetraenoic acid (5-HETE) reaching its maximum after 1 - 2 hours of co-incubation of fibroblasts and platelets. The 5-HETE production was reduced by the inhibitors DMDA, ETYA and ETI. In conclusion, this study suggests that platelet-stimulated proliferation of fibroblasts is mediated by an increased 5-LOX activity, which supports recent findings indicating a crucial role for this enzyme in proliferative disorders such as atherosclerosis.

Identification of regions of leukotriene C4synthase which direct the enzyme to its nuclear envelope localization

Leukotrienes (LTs) are fatty acid derivatives formed by oxygenation of arachidonic acid via the 5-lipoxygenase (5-LO) pathway. Upon activation of inflammatory cells 5-LO is translocated to the nuclear envelope (NE) where it converts arachidonic acid to the unstable epoxide LTA4. LTA4 is further converted to LTC4 by conjugation with glutathione, a reaction catalyzed by the integral membrane protein LTC4 synthase (LTC4S), which is localized on the NE and endoplasmic reticulum (ER). We now report the mapping of regions of LTC4S that are important for its subcellular localization. Multiple constructs encoding fusion proteins of green fluorescent protein (GFP) as the N-terminal part and various truncated variants of human LTC4S as C-terminal part were prepared and transfected into HEK 293/T or COS-7 cells. Constructs encoding hydrophobic region 1 of LTC4S (amino acids 6-27) did not give distinct membrane localized fluorescence. In contrast hydrophobic region 2 (amino acids 60-89) gave a localization pattern similar to that of full length LTC4S. Hydrophobic region 3 (amino acids 114-135) directed GFP to a localization indistinguishable from that of full length LTC4S. A minimal directing sequence, amino acids 117-132, was identified by further truncation. The involvement of the hydrophobic regions in the homo-oligomerization of LTC4S was investigated using bioluminescence resonance energy transfer (BRET) analysis in living cells. BRET data showed that hydrophobic regions 1 and 3 each allowed oligomerization to occur. These regions most likely form transmembrane helices, suggesting that homo-oligomerization of LTC4S is due to helix-helix interactions in the membrane.