Background Long-term childhood conditions are often managed by hospital-based multidisciplinary t... more Background Long-term childhood conditions are often managed by hospital-based multidisciplinary teams (MDTs) of professionals with discipline specific expertise of a condition, in partnership with parents. However, little evidence exists on professional-parent interactions in this context. An exploration of professionals' accounts of the way they individually and collectively teach parents to manage their child's clinical care at home is, therefore, important for meeting parents' needs, informing policy and educating novice professionals. Using chronic kidney disease as an exemplar this paper reports on one aspect of a study of interactions between professionals and parents in a network of 12 children's kidney units in Britain. Methods We conducted semi-structured, qualitative interviews with a convenience sample of 112 professionals (clinical-psychologists, dietitians, doctors, nurses, pharmacists, play-workers, therapists and social workers), exploring accounts of their parent-educative activity. We analysed data using framework and the concept of distributed expertise. bs_bs_banner Child: care, health and development Original Article
Percutaneous renal biopsy under real time ultrasound guidance is a routine procedure in pediatric... more Percutaneous renal biopsy under real time ultrasound guidance is a routine procedure in pediatric nephrology and allows a histological diagnosis to be made in children with evidence of renal disease. Retrospective case note review. Over four years 191 renal biopsies were attempted in 116 patients; 186 biopsies were performed successfully: 102 native and 84 renal allografts. 151 renal biopsies were performed under sedation and 34 biopsies were performed under general anesthetic, one biopsy without sedation. Problems during sedation were recorded in 5/151 (3.3%) cases. All patients remained in hospital overnight for observation following the biopsy. Complications were reported in 23/185 (12%) of biopsies. Macroscopic hematuria was recorded in 13/185 (7%), presenting within 6-hours of biopsy, on first void, in 11 patients. Two patients developed macroscopic hematuria four and six days after the procedure. One patient with macroscopic hematuria required a single blood transfusion. Three...
Public concern about wind erosion in the United States rangelands is increasing. This concern has... more Public concern about wind erosion in the United States rangelands is increasing. This concern has arisen as a consequence of changing and intensifying land use pressures which can lead to increased soil loss and dust emissions. However, there is relatively little research to support improved management. While much attention has been given to measuring and modelling wind erosion in US cropping systems, there is a dearth of information on the magnitude and frequency of wind erosion in rangelands and other land cover types. Resolving this knowledge gap is important for addressing the multiple impacts of land use and land cover change, including those related to soil nutrient loss and productivity, snow hydrology, public health and climate. Field measurements of aeolian sediment transport rates supported by predictive models are needed to quantify wind erosion across all land cover types so that the impacts can be assessed and management solutions identified and tested. We present a new...
The Kalahari encompasses one of the largest drylands in the Southern Hemisphere and it is a poten... more The Kalahari encompasses one of the largest drylands in the Southern Hemisphere and it is a potentially large source of atmospheric dust in its relatively low-dust region. The severe iron depletion in the southern Indian and Atlantic Oceans, the ocean basins that receive much of the Kalahari dust, suggests that even incremental increases in dust export to these basins could have significant impact on ocean productivity. The Kalahari also provides an excellent “natural laboratory”, due to its consistent Kalahari Sands existing along a strong precipitation gradient (from ~850 mm in southern Zambia to ~150 mm in southwestern Botswana) with a range of different land uses and land use intensities. A large-scale field campaign to evaluate the potential of the southern Kalahari to produce atmospheric dust was established in August, 2013. The goal of the experiment is to evaluate the potential of climate change and land-use to contribute to dust production. The experiment includes measureme...
Clinical journal of the American Society of Nephrology : CJASN, Jan 7, 2014
Once-daily losartan reduces BP in a dose-dependent manner and is well tolerated in hypertensive c... more Once-daily losartan reduces BP in a dose-dependent manner and is well tolerated in hypertensive children aged 6-16 years. This study assessed the dose-response relationship, safety, and tolerability of losartan in hypertensive children aged 6 months to 6 years. This was a 12-week, randomized, open-label, dose-ranging study, with a 2-year extension. Patients were randomized to losartan at the following dosages: 0.1 mg/kg per day (low), 0.3 mg/kg per day (medium), or 0.7 mg/kg per day (high). Losartan was titrated to the next dose level (to a 1.4 mg/kg per day maximum dosage, not exceeding 100 mg/d, which was not one of the three original doses offered at randomization) at weeks 3, 6, and 9 for patients who did not attain their goal BP and were not taking the highest dose. Dose response was evaluated by analyzing the slope of change in sitting systolic BP (SBP; primary end point) and diastolic BP (DBP; secondary end point) after 3 weeks compared with baseline. Adverse events (AEs) wer...
The aims of this study were (1) to ascertain ciclosporin C 2 levels currently being achieved in c... more The aims of this study were (1) to ascertain ciclosporin C 2 levels currently being achieved in children with steroid-sensitive nephrotic syndrome (SSNS) and renal transplants (RTs), (2) to determine the feasibility of the use of finger-prick samples for the measurement of ciclosporin levels, and (3) to identify any correlation between hypertrichosis or gingival overgrowth (GO) and level of ciclosporin 2 h post-dose (C 2 ). Seventy-two children (39 with SSNS, 33 with RT) participated. Ciclosporin 12 h trough (C 12 ) and C 2 levels were measured in venous and finger-prick samples by high-performance liquid chromatography tandem mass spectroscopy. Photographs of the teeth and back were taken for assessment of GO and hypertrichosis. Mean (±SD) C 2 levels in the SSNS and RT groups were 512 (±181) μg/l and 471 (±229) μg/l. There was a highly significant relationship between venous and finger-prick ciclosporin levels (r 2 =0.96, P<0.0001). Fourteen children had severe GO. There was a small, though statistically significant, impact of ciclosporin level on GO (C 2 r 2 =0.12, P=0.003 and C 12 r 2 =0.06, P=0.038) but no correlation with dose (milligrammes per kilogramme per day or milligrammes per square metre per day) or duration. Seventeen children had moderate or severe hypertrichosis, this being more common in children of South Asian ethnicity (P<0.0001). There was no correlation between ciclosporin exposure or duration and hypertrichosis. Fingerprick blood sampling may serve as a practical alternative to venepuncture in children receiving ciclosporin.
This retrospective study investigated the outcome of 27 children (19 male) with Henoch-Schönlein ... more This retrospective study investigated the outcome of 27 children (19 male) with Henoch-Schönlein purpura nephritis (HSN) of International Study of Kidney Disease in Children (ISKDC) grade 3b or higher treated with longterm immunosuppressive therapy in a single centre over a 10-year period. The mean age at presentation was 9.7 years. The median estimated glomerular filtration rate (eGFR) was 91.3 ml/min per 1.73 m 2 , with the median urine protein creatinine ratio (UP:UC) 556 mg/mmol. The treatment protocol comprised daily steroids and cyclophosphamide for 8-12 weeks followed by azathioprine and a reducing regimen of alternate-day steroids for 8-12 months. After a mean follow-up period of 7 years following presentation, 37% made a complete recovery, 40.7% had persistent proteinuria, 7.4% had persistent proteinuria and were on antihypertensive therapy and 14.8% had progressed to endstage kidney failure (ESKF). Children with poor outcome were older at presentation (p 0.005), had more crescents (p 0.015) and had heavier proteinuria 6 months post initial biopsy (p 0.023). All of the four children with ESKF had nephrotic range proteinuria and greater than 50% crescents on initial biopsy. Despite long-term immunosuppression, the majority of children with HSN grade 3b or higher will have persistent renal abnormalities on long-term follow-up.
ABSTRACT The parameterisation of surface roughness effects on aeolian sediment transport is a key... more ABSTRACT The parameterisation of surface roughness effects on aeolian sediment transport is a key source of uncertainty in wind erosion models. Roughness effects are typically represented by bulk drag-partitioning schemes that scale the threshold friction velocity (u*t) for soil entrainment by the ratio of shear stress on roughness elements to that on the vegetated land surface. However, the approach does not explicitly account for the effects of roughness configuration, which may be important for sediment flux. In this study we investigate (1) the significance of roughness configuration for aeolian sediment transport, (2) the ability of drag partitioning approaches to represent roughness configuration effects, and (3) the implications of our findings for model applications. We use wind tunnel measurements of surface shear stress distributions to calculate sediment flux for a suite of roughness configurations, roughness densities and wind velocities. Our results show that roughness configuration has a significant effect on sediment flux, influencing estimates by more than one order-of-magnitude. Measured and modelled drag partitioning approaches overestimate the predicted flux by two to three orders-of-magnitude. The drag partition is sensitive to roughness configuration, but current models cannot effectively represent this sensitivity. The effectiveness of drag partitioning approaches is also affected by estimates of the aerodynamic roughness height (z0) used to calculate wind shear velocity (u*). Unless the roughness height is consistent with the drag partition and u*t, resulting fluxes can show physically implausible patterns. These results should make us question current assessments of the magnitude of vegetated dryland dust emissions. Representing roughness effects on surface shear stress distributions will reduce uncertainty in quantifying wind erosion, enabling better assessment of its impacts and management solutions.
Journal of the American Society of Nephrology : JASN, Jan 27, 2014
Steroid-sensitive nephrotic syndrome (SSNS) accounts for >80% of cases of nephrotic syndrome i... more Steroid-sensitive nephrotic syndrome (SSNS) accounts for >80% of cases of nephrotic syndrome in childhood. However, the etiology and pathogenesis of SSNS remain obscure. Hypothesizing that coding variation may underlie SSNS risk, we conducted an exome array association study of SSNS. We enrolled a discovery set of 363 persons (214 South Asian children with SSNS and 149 controls) and genotyped them using the Illumina HumanExome Beadchip. Four common single nucleotide polymorphisms (SNPs) in HLA-DQA1 and HLA-DQB1 (rs1129740, rs9273349, rs1071630, and rs1140343) were significantly associated with SSNS at or near the Bonferroni-adjusted P value for the number of single variants that were tested (odds ratio, 2.11; 95% confidence interval, 1.56 to 2.86; P=1.68×10(-6) (Fisher exact test). Two of these SNPs-the missense variants C34Y (rs1129740) and F41S (rs1071630) in HLA-DQA1-were replicated in an independent cohort of children of white European ancestry with SSNS (100 cases and ≤589 c...
In recent decades, large areas of rangeland have been converted to cropland or vice versa in the ... more In recent decades, large areas of rangeland have been converted to cropland or vice versa in the western United States and elsewhere in the world, driven largely by increased crop prices, loss of access to irrigation water, and agricultural expansion/contraction. Wind erosion and dust emissions are key processes that have not been well studied during land use and associated land cover changes. This assessment is challenging because currently no model is available that can provide field-to landscape-scale estimates of wind erosion on both rangeland and cropland, and account for soil, vegetation and management changes. In this paper, we compare aeolian sediment transport estimates from available cropland models and a number of mass flux equations developed for rangelands, for a bare soil surface with different levels of crust and surface roughness under different wind speeds. Our results show that the simulated horizontal sediment mass fluxes are similar for cropland and rangeland models at large surface crust coverage and aerodynamic roughness. In situations of small to moderate crust cover and soil roughness, horizontal mass fluxes varied by over three orders of magnitude among the tested models. A correlation analysis shows that horizontal mass fluxes simulated by cropland and rangeland models are correlated, with correlation R 2 of 0.37-0.99 across different models. Finally, we propose an approach to estimate changes in aeolian transport with changes in land use. Although this approach may be limited to situations of unvegetated surfaces, it provides a preliminary method for land managers and policymakers to estimate potential wind erosion changes in response to land use change.
Corticosteroid withdrawal (CW) after pediatric kidney transplantation potentially improves growth... more Corticosteroid withdrawal (CW) after pediatric kidney transplantation potentially improves growth while avoiding metabolic and other adverse effects. We have recently reported the results of a 196 subject randomized controlled trial comparing early CW (tacrolimus, mycophenolate mofetil (MMF), daclizumab, and corticosteroids until day 4) with tacrolimus, MMF, and corticosteroid continuation (CC). At 6 months, CW subjects showed better growth with no adverse impact on acute rejection or graft survival (Am J Transplant 2010; 10: 828-836). This 2-year investigator-driven follow-up study aimed to determine whether improved growth persisted in the longer term. Data regarding growth, graft outcomes and adverse events were collected at 1 year (113 patients) and 2 years (106 patients) after transplantation. The primary endpoint, longitudinal growth calculated as delta height standard deviation score, was analyzed using a mixed model repeated measures model. Corticosteroid withdrawal subjects grew better at 1 year (difference in adjusted mean change, 0.25; 95% confidence interval, 0.10, 0.40; P=0.001). At 2 years, growth remained numerically better in CW subjects (0.20 (-0.01, 0.41); P=0.06), and significantly better in prepubertal subjects (0.50 (0.16, 0.84); P=0.004). Bacterial and viral infection was significantly more common in CW subjects at 1 year only. Corticosteroid withdrawal and corticosteroid continuation subjects received similar exposure to both tacrolimus and MMF at 1 and 2 years. No significant difference in patient or graft survival, rejection, estimated glomerular filtration rate, or other adverse events was detected. Early CW effectively and safely improves growth up to 2 years after transplantation, particularly in prepubertal children.
Focal segmental glomerulosclerosis (FSGS) is a histological lesion with many causes, including in... more Focal segmental glomerulosclerosis (FSGS) is a histological lesion with many causes, including inherited genetic defects, with significant proteinuria being the predominant clinical finding at presentation. Mutations in COL4A3 and COL4A4 are known to cause Alport syndrome (AS), thin basement membrane nephropathy, and to result in pathognomonic glomerular basement membrane (GBM) findings. Secondary FSGS is known to develop in classic AS at later stages of the disease. Here, we present seven families with rare or novel variants in COL4A3 or COL4A4 (six with single and one with two heterozygous variants) from a cohort of 70 families with a diagnosis of hereditary FSGS. The predominant clinical finding at diagnosis was proteinuria associated with hematuria. In all seven families, there were individuals with nephrotic-range proteinuria with histologic features of FSGS by light microscopy. In one family, electron microscopy showed thin GBM, but four other families had variable findings in...
Nephrotic syndrome is the commonest glomerular disease affecting children and is frequently encou... more Nephrotic syndrome is the commonest glomerular disease affecting children and is frequently encountered in general paediatrics. The most common subtype is minimal change nephrotic syndrome which typically occurs in preschool children and responds well to ...
Long-term childhood conditions are often managed by hospital-based multidisciplinary teams of pro... more Long-term childhood conditions are often managed by hospital-based multidisciplinary teams of professionals with discipline specific expertise of a condition, in partnership with parents. However, little evidence exists on professional-parent interactions in this context. An exploration of professionals' accounts of the way they individually and collectively teach parents to manage their child's clinical care at home is, therefore, important for meeting parents' needs, informing policy and educating novice professionals. Using chronic kidney disease as an exemplar this paper reports on one aspect of a study of interactions between professionals and parents in a network of 12 children's kidney units in Britain.
Informatics for health & social care, Jan 13, 2014
Background: Few evidence-based, on-line resources exist to support home-based care of childhood l... more Background: Few evidence-based, on-line resources exist to support home-based care of childhood long-term conditions. Methods: In a feasibility study, children with stages 3, 4 or 5 chronic kidney disease, parents and professionals collaboratively developed a novel Online Parent Information and Support (OPIS) application. Parents were randomized to an intervention arm with access to OPIS or a control arm without access. OPIS usage was assessed using Google Analytics. Parents in the intervention arm completed the Suitability Assessment of Materials (SAM) and User Interface Satisfaction (USE) questionnaires and participated in qualitative interviews. Results: Twenty parents accessed OPIS with a mean of 23.3 (SD 20.8, range 2-64) visits per user. Responses from the SAM and USE questionnaires were positive, most respondents rating OPIS highly and finding it easy to use. Qualitative suggestions include refinement of OPIS components, enabling personalization of OPIS functionalities and pr...
Information booklets for parents of children with Minimal Change Nephrotic syndrome are currently... more Information booklets for parents of children with Minimal Change Nephrotic syndrome are currently in general circulation in the UK This study set out to discover what information parents require in a general information booklet, and whether the present ...
Background Long-term childhood conditions are often managed by hospital-based multidisciplinary t... more Background Long-term childhood conditions are often managed by hospital-based multidisciplinary teams (MDTs) of professionals with discipline specific expertise of a condition, in partnership with parents. However, little evidence exists on professional-parent interactions in this context. An exploration of professionals' accounts of the way they individually and collectively teach parents to manage their child's clinical care at home is, therefore, important for meeting parents' needs, informing policy and educating novice professionals. Using chronic kidney disease as an exemplar this paper reports on one aspect of a study of interactions between professionals and parents in a network of 12 children's kidney units in Britain. Methods We conducted semi-structured, qualitative interviews with a convenience sample of 112 professionals (clinical-psychologists, dietitians, doctors, nurses, pharmacists, play-workers, therapists and social workers), exploring accounts of their parent-educative activity. We analysed data using framework and the concept of distributed expertise. bs_bs_banner Child: care, health and development Original Article
Percutaneous renal biopsy under real time ultrasound guidance is a routine procedure in pediatric... more Percutaneous renal biopsy under real time ultrasound guidance is a routine procedure in pediatric nephrology and allows a histological diagnosis to be made in children with evidence of renal disease. Retrospective case note review. Over four years 191 renal biopsies were attempted in 116 patients; 186 biopsies were performed successfully: 102 native and 84 renal allografts. 151 renal biopsies were performed under sedation and 34 biopsies were performed under general anesthetic, one biopsy without sedation. Problems during sedation were recorded in 5/151 (3.3%) cases. All patients remained in hospital overnight for observation following the biopsy. Complications were reported in 23/185 (12%) of biopsies. Macroscopic hematuria was recorded in 13/185 (7%), presenting within 6-hours of biopsy, on first void, in 11 patients. Two patients developed macroscopic hematuria four and six days after the procedure. One patient with macroscopic hematuria required a single blood transfusion. Three...
Public concern about wind erosion in the United States rangelands is increasing. This concern has... more Public concern about wind erosion in the United States rangelands is increasing. This concern has arisen as a consequence of changing and intensifying land use pressures which can lead to increased soil loss and dust emissions. However, there is relatively little research to support improved management. While much attention has been given to measuring and modelling wind erosion in US cropping systems, there is a dearth of information on the magnitude and frequency of wind erosion in rangelands and other land cover types. Resolving this knowledge gap is important for addressing the multiple impacts of land use and land cover change, including those related to soil nutrient loss and productivity, snow hydrology, public health and climate. Field measurements of aeolian sediment transport rates supported by predictive models are needed to quantify wind erosion across all land cover types so that the impacts can be assessed and management solutions identified and tested. We present a new...
The Kalahari encompasses one of the largest drylands in the Southern Hemisphere and it is a poten... more The Kalahari encompasses one of the largest drylands in the Southern Hemisphere and it is a potentially large source of atmospheric dust in its relatively low-dust region. The severe iron depletion in the southern Indian and Atlantic Oceans, the ocean basins that receive much of the Kalahari dust, suggests that even incremental increases in dust export to these basins could have significant impact on ocean productivity. The Kalahari also provides an excellent “natural laboratory”, due to its consistent Kalahari Sands existing along a strong precipitation gradient (from ~850 mm in southern Zambia to ~150 mm in southwestern Botswana) with a range of different land uses and land use intensities. A large-scale field campaign to evaluate the potential of the southern Kalahari to produce atmospheric dust was established in August, 2013. The goal of the experiment is to evaluate the potential of climate change and land-use to contribute to dust production. The experiment includes measureme...
Clinical journal of the American Society of Nephrology : CJASN, Jan 7, 2014
Once-daily losartan reduces BP in a dose-dependent manner and is well tolerated in hypertensive c... more Once-daily losartan reduces BP in a dose-dependent manner and is well tolerated in hypertensive children aged 6-16 years. This study assessed the dose-response relationship, safety, and tolerability of losartan in hypertensive children aged 6 months to 6 years. This was a 12-week, randomized, open-label, dose-ranging study, with a 2-year extension. Patients were randomized to losartan at the following dosages: 0.1 mg/kg per day (low), 0.3 mg/kg per day (medium), or 0.7 mg/kg per day (high). Losartan was titrated to the next dose level (to a 1.4 mg/kg per day maximum dosage, not exceeding 100 mg/d, which was not one of the three original doses offered at randomization) at weeks 3, 6, and 9 for patients who did not attain their goal BP and were not taking the highest dose. Dose response was evaluated by analyzing the slope of change in sitting systolic BP (SBP; primary end point) and diastolic BP (DBP; secondary end point) after 3 weeks compared with baseline. Adverse events (AEs) wer...
The aims of this study were (1) to ascertain ciclosporin C 2 levels currently being achieved in c... more The aims of this study were (1) to ascertain ciclosporin C 2 levels currently being achieved in children with steroid-sensitive nephrotic syndrome (SSNS) and renal transplants (RTs), (2) to determine the feasibility of the use of finger-prick samples for the measurement of ciclosporin levels, and (3) to identify any correlation between hypertrichosis or gingival overgrowth (GO) and level of ciclosporin 2 h post-dose (C 2 ). Seventy-two children (39 with SSNS, 33 with RT) participated. Ciclosporin 12 h trough (C 12 ) and C 2 levels were measured in venous and finger-prick samples by high-performance liquid chromatography tandem mass spectroscopy. Photographs of the teeth and back were taken for assessment of GO and hypertrichosis. Mean (±SD) C 2 levels in the SSNS and RT groups were 512 (±181) μg/l and 471 (±229) μg/l. There was a highly significant relationship between venous and finger-prick ciclosporin levels (r 2 =0.96, P<0.0001). Fourteen children had severe GO. There was a small, though statistically significant, impact of ciclosporin level on GO (C 2 r 2 =0.12, P=0.003 and C 12 r 2 =0.06, P=0.038) but no correlation with dose (milligrammes per kilogramme per day or milligrammes per square metre per day) or duration. Seventeen children had moderate or severe hypertrichosis, this being more common in children of South Asian ethnicity (P<0.0001). There was no correlation between ciclosporin exposure or duration and hypertrichosis. Fingerprick blood sampling may serve as a practical alternative to venepuncture in children receiving ciclosporin.
This retrospective study investigated the outcome of 27 children (19 male) with Henoch-Schönlein ... more This retrospective study investigated the outcome of 27 children (19 male) with Henoch-Schönlein purpura nephritis (HSN) of International Study of Kidney Disease in Children (ISKDC) grade 3b or higher treated with longterm immunosuppressive therapy in a single centre over a 10-year period. The mean age at presentation was 9.7 years. The median estimated glomerular filtration rate (eGFR) was 91.3 ml/min per 1.73 m 2 , with the median urine protein creatinine ratio (UP:UC) 556 mg/mmol. The treatment protocol comprised daily steroids and cyclophosphamide for 8-12 weeks followed by azathioprine and a reducing regimen of alternate-day steroids for 8-12 months. After a mean follow-up period of 7 years following presentation, 37% made a complete recovery, 40.7% had persistent proteinuria, 7.4% had persistent proteinuria and were on antihypertensive therapy and 14.8% had progressed to endstage kidney failure (ESKF). Children with poor outcome were older at presentation (p 0.005), had more crescents (p 0.015) and had heavier proteinuria 6 months post initial biopsy (p 0.023). All of the four children with ESKF had nephrotic range proteinuria and greater than 50% crescents on initial biopsy. Despite long-term immunosuppression, the majority of children with HSN grade 3b or higher will have persistent renal abnormalities on long-term follow-up.
ABSTRACT The parameterisation of surface roughness effects on aeolian sediment transport is a key... more ABSTRACT The parameterisation of surface roughness effects on aeolian sediment transport is a key source of uncertainty in wind erosion models. Roughness effects are typically represented by bulk drag-partitioning schemes that scale the threshold friction velocity (u*t) for soil entrainment by the ratio of shear stress on roughness elements to that on the vegetated land surface. However, the approach does not explicitly account for the effects of roughness configuration, which may be important for sediment flux. In this study we investigate (1) the significance of roughness configuration for aeolian sediment transport, (2) the ability of drag partitioning approaches to represent roughness configuration effects, and (3) the implications of our findings for model applications. We use wind tunnel measurements of surface shear stress distributions to calculate sediment flux for a suite of roughness configurations, roughness densities and wind velocities. Our results show that roughness configuration has a significant effect on sediment flux, influencing estimates by more than one order-of-magnitude. Measured and modelled drag partitioning approaches overestimate the predicted flux by two to three orders-of-magnitude. The drag partition is sensitive to roughness configuration, but current models cannot effectively represent this sensitivity. The effectiveness of drag partitioning approaches is also affected by estimates of the aerodynamic roughness height (z0) used to calculate wind shear velocity (u*). Unless the roughness height is consistent with the drag partition and u*t, resulting fluxes can show physically implausible patterns. These results should make us question current assessments of the magnitude of vegetated dryland dust emissions. Representing roughness effects on surface shear stress distributions will reduce uncertainty in quantifying wind erosion, enabling better assessment of its impacts and management solutions.
Journal of the American Society of Nephrology : JASN, Jan 27, 2014
Steroid-sensitive nephrotic syndrome (SSNS) accounts for >80% of cases of nephrotic syndrome i... more Steroid-sensitive nephrotic syndrome (SSNS) accounts for >80% of cases of nephrotic syndrome in childhood. However, the etiology and pathogenesis of SSNS remain obscure. Hypothesizing that coding variation may underlie SSNS risk, we conducted an exome array association study of SSNS. We enrolled a discovery set of 363 persons (214 South Asian children with SSNS and 149 controls) and genotyped them using the Illumina HumanExome Beadchip. Four common single nucleotide polymorphisms (SNPs) in HLA-DQA1 and HLA-DQB1 (rs1129740, rs9273349, rs1071630, and rs1140343) were significantly associated with SSNS at or near the Bonferroni-adjusted P value for the number of single variants that were tested (odds ratio, 2.11; 95% confidence interval, 1.56 to 2.86; P=1.68×10(-6) (Fisher exact test). Two of these SNPs-the missense variants C34Y (rs1129740) and F41S (rs1071630) in HLA-DQA1-were replicated in an independent cohort of children of white European ancestry with SSNS (100 cases and ≤589 c...
In recent decades, large areas of rangeland have been converted to cropland or vice versa in the ... more In recent decades, large areas of rangeland have been converted to cropland or vice versa in the western United States and elsewhere in the world, driven largely by increased crop prices, loss of access to irrigation water, and agricultural expansion/contraction. Wind erosion and dust emissions are key processes that have not been well studied during land use and associated land cover changes. This assessment is challenging because currently no model is available that can provide field-to landscape-scale estimates of wind erosion on both rangeland and cropland, and account for soil, vegetation and management changes. In this paper, we compare aeolian sediment transport estimates from available cropland models and a number of mass flux equations developed for rangelands, for a bare soil surface with different levels of crust and surface roughness under different wind speeds. Our results show that the simulated horizontal sediment mass fluxes are similar for cropland and rangeland models at large surface crust coverage and aerodynamic roughness. In situations of small to moderate crust cover and soil roughness, horizontal mass fluxes varied by over three orders of magnitude among the tested models. A correlation analysis shows that horizontal mass fluxes simulated by cropland and rangeland models are correlated, with correlation R 2 of 0.37-0.99 across different models. Finally, we propose an approach to estimate changes in aeolian transport with changes in land use. Although this approach may be limited to situations of unvegetated surfaces, it provides a preliminary method for land managers and policymakers to estimate potential wind erosion changes in response to land use change.
Corticosteroid withdrawal (CW) after pediatric kidney transplantation potentially improves growth... more Corticosteroid withdrawal (CW) after pediatric kidney transplantation potentially improves growth while avoiding metabolic and other adverse effects. We have recently reported the results of a 196 subject randomized controlled trial comparing early CW (tacrolimus, mycophenolate mofetil (MMF), daclizumab, and corticosteroids until day 4) with tacrolimus, MMF, and corticosteroid continuation (CC). At 6 months, CW subjects showed better growth with no adverse impact on acute rejection or graft survival (Am J Transplant 2010; 10: 828-836). This 2-year investigator-driven follow-up study aimed to determine whether improved growth persisted in the longer term. Data regarding growth, graft outcomes and adverse events were collected at 1 year (113 patients) and 2 years (106 patients) after transplantation. The primary endpoint, longitudinal growth calculated as delta height standard deviation score, was analyzed using a mixed model repeated measures model. Corticosteroid withdrawal subjects grew better at 1 year (difference in adjusted mean change, 0.25; 95% confidence interval, 0.10, 0.40; P=0.001). At 2 years, growth remained numerically better in CW subjects (0.20 (-0.01, 0.41); P=0.06), and significantly better in prepubertal subjects (0.50 (0.16, 0.84); P=0.004). Bacterial and viral infection was significantly more common in CW subjects at 1 year only. Corticosteroid withdrawal and corticosteroid continuation subjects received similar exposure to both tacrolimus and MMF at 1 and 2 years. No significant difference in patient or graft survival, rejection, estimated glomerular filtration rate, or other adverse events was detected. Early CW effectively and safely improves growth up to 2 years after transplantation, particularly in prepubertal children.
Focal segmental glomerulosclerosis (FSGS) is a histological lesion with many causes, including in... more Focal segmental glomerulosclerosis (FSGS) is a histological lesion with many causes, including inherited genetic defects, with significant proteinuria being the predominant clinical finding at presentation. Mutations in COL4A3 and COL4A4 are known to cause Alport syndrome (AS), thin basement membrane nephropathy, and to result in pathognomonic glomerular basement membrane (GBM) findings. Secondary FSGS is known to develop in classic AS at later stages of the disease. Here, we present seven families with rare or novel variants in COL4A3 or COL4A4 (six with single and one with two heterozygous variants) from a cohort of 70 families with a diagnosis of hereditary FSGS. The predominant clinical finding at diagnosis was proteinuria associated with hematuria. In all seven families, there were individuals with nephrotic-range proteinuria with histologic features of FSGS by light microscopy. In one family, electron microscopy showed thin GBM, but four other families had variable findings in...
Nephrotic syndrome is the commonest glomerular disease affecting children and is frequently encou... more Nephrotic syndrome is the commonest glomerular disease affecting children and is frequently encountered in general paediatrics. The most common subtype is minimal change nephrotic syndrome which typically occurs in preschool children and responds well to ...
Long-term childhood conditions are often managed by hospital-based multidisciplinary teams of pro... more Long-term childhood conditions are often managed by hospital-based multidisciplinary teams of professionals with discipline specific expertise of a condition, in partnership with parents. However, little evidence exists on professional-parent interactions in this context. An exploration of professionals' accounts of the way they individually and collectively teach parents to manage their child's clinical care at home is, therefore, important for meeting parents' needs, informing policy and educating novice professionals. Using chronic kidney disease as an exemplar this paper reports on one aspect of a study of interactions between professionals and parents in a network of 12 children's kidney units in Britain.
Informatics for health & social care, Jan 13, 2014
Background: Few evidence-based, on-line resources exist to support home-based care of childhood l... more Background: Few evidence-based, on-line resources exist to support home-based care of childhood long-term conditions. Methods: In a feasibility study, children with stages 3, 4 or 5 chronic kidney disease, parents and professionals collaboratively developed a novel Online Parent Information and Support (OPIS) application. Parents were randomized to an intervention arm with access to OPIS or a control arm without access. OPIS usage was assessed using Google Analytics. Parents in the intervention arm completed the Suitability Assessment of Materials (SAM) and User Interface Satisfaction (USE) questionnaires and participated in qualitative interviews. Results: Twenty parents accessed OPIS with a mean of 23.3 (SD 20.8, range 2-64) visits per user. Responses from the SAM and USE questionnaires were positive, most respondents rating OPIS highly and finding it easy to use. Qualitative suggestions include refinement of OPIS components, enabling personalization of OPIS functionalities and pr...
Information booklets for parents of children with Minimal Change Nephrotic syndrome are currently... more Information booklets for parents of children with Minimal Change Nephrotic syndrome are currently in general circulation in the UK This study set out to discover what information parents require in a general information booklet, and whether the present ...
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Papers by Nicholas Webb