HEREDITARY ENDOCRINE TUMOURS: CURRENT STATE-OF-THE-ART AND RESEARCH OPPORTUNITIES: MEN1-related pancreatic NETs: identification of unmet clinical needs and future directives

The PanNET Working Group of the 16th International Multiple Endocrine Neoplasia Workshop (MEN2019) convened in Houston, TX, USA, 27-29 March 2019 to discuss key unmet clinical needs related to PanNET in the context of MEN1, with a special focus on non-functioning (nf)-PanNETs. The participants represented a broad range of medical scientists as well as representatives from patient organizations, pharmaceutical industry and research societies. In a case-based approach, participants addressed early detection, surveillance, prognostic factors and management of localized and advanced disease. For each topic, after a review of current evidence, key unmet clinical needs and future research directives to make meaningful progress for MEN1 patients with nf-PanNETs were identified. International multi-institutional collaboration is needed for adequately sized studies and validation of findings in independent datasets. Collaboration between basic, translational and clinical scientists is paramount to establishing a translational science approach. In addition, bringing clinicians, scientists and patients together improves the prioritization of research goals, assures a patient-centered approach and maximizes patient involvement. It was concluded that collaboration, research infrastructure, methodologic and reporting rigor are essential to any translational science effort. The highest priority for nf-PanNETs in MEN1 syndrome are (1) the development of a data and biospecimen collection architecture that is uniform across all MEN1 centers, (2) unified strategies for diagnosis and follow-up of incident and prevalent nf-PanNETs, (3) non-invasive detection of individual nf-PanNETs that have an increased risk of metastasis, (4) chemoprevention clinical trials driven by basic research studies and (5) therapeutic targets for advanced disease based on biologically plausible mechanisms.

A method for screening groundwater vulnerability from subsurface hydrocarbon extraction practices

This paper describes a new screening method for assessing groundwater vulnerability to pollution from hydrocarbon exploitation in the subsurface. The method can be used for various hydrocarbon energy sources, including conventional oil and gas, shale gas and oil, coal bed methane and underground coal gasification. Intrinsic vulnerability of potential receptors is assessed at any particular location by identifying possible geological pathways for contaminant transport. This is followed by an assessment of specific vulnerability which takes into account the nature of the subsurface hydrocarbon activity and driving heads. A confidence rating is attached to each parameter in the assessment to provide an indication of the confidence in the screening. Risk categories and associated confidence ratings are designed to aid in environmental decision making, regulation and management, highlighting where additional information is required. The method is demonstrated for conventional gas and proposed shale gas operations in northern England but can be adapted for use in any geological or hydrogeological setting and for other subsurface activities.

Management of bone disease in cystinosis: Statement from an international conference

Cystinosis is an autosomal recessive storage disease due to impaired transport of cystine out of lysosomes. Since the accumulation of intracellular cystine affects all organs and tissues, the management of cystinosis requires a specialized multidisciplinary team consisting of pediatricians, nephrologists, nutritionists, ophthalmologists, endocrinologists, neurologists' geneticists, and orthopedic surgeons. Treatment with cysteamine can delay or prevent most clinical manifestations of cystinosis, except the renal Fanconi syndrome. Virtually all individuals with classical, nephropathic cystinosis suffer from cystinosis metabolic bone disease (CMBD), related to the renal Fanconi syndrome in infancy and progressive chronic kidney disease (CKD) later in life. Manifestations of CMBD include hypophosphatemic rickets in infancy, and renal osteodystrophy associated with CKD resulting in bone deformities, osteomalacia, osteoporosis, fractures, and short stature. Assessment of CMBD involves monitoring growth, leg deformities, blood levels of phosphate, electrolytes, bicarbonate, calcium, and alkaline phosphatase, periodically obtaining bone radiographs, determining levels of critical hormones and vitamins, such as thyroid hormone, parathyroid hormone, 25(OH) vitamin D, and testosterone in males, and surveillance for nonrenal complications of cystinosis such as myopathy. Treatment includes replacement of urinary losses, cystine depletion with oral cysteamine, vitamin D, hormone replacement, physical therapy, and corrective orthopedic surgery. The recommendations in this article came from an expert meeting on CMBD that took place in Salzburg, Austria, in December 2016.

Global patterns of nitrate storage in the vadose zone

Global-scale nitrogen budgets developed to quantify anthropogenic impacts on the nitrogen cycle do not explicitly consider nitrate stored in the vadose zone. Here we show that the vadose zone is an important store of nitrate that should be considered in future budgets for effective policymaking. Using estimates of groundwater depth and nitrate leaching for 1900–2000, we quantify the peak global storage of nitrate in the vadose zone as 605–1814 Teragrams (Tg). Estimates of nitrate storage are validated using basin-scale and national-scale estimates and observed groundwater nitrate data. Nitrate storage per unit area is greatest in North America, China and Europe where there are thick vadose zones and extensive historical agriculture. In these areas, long travel times in the vadose zone may delay the impact of changes in agricultural practices on groundwater quality. We argue that in these areas use of conventional nitrogen budget approaches is inappropriate.

Current global-scale nitrogen (N) budgets quantifying anthropogenic impacts on the N cycle do not explicitly consider nitrate storage in the vadose zone. Here, using estimates of depth to groundwater and nitrate leaching between 1900–2000, the authors show that the vadose zone is an important store of nitrate.

Aggregation and a strong Allee effect in a cooperative outbreak insect

Most species that are negatively impacted when their densities are low aggregate to minimize this effect. Aggregation has the potential to change how Allee effects are expressed at the population level. We studied the interplay between aggregation and Allee effects in the mountain pine beetle (Dendroctonus ponderosae Hopkins), an irruptive bark beetle that aggregates to overcome tree defenses. By cooperating to surpass a critical number of attacks per tree, the mountain pine beetle is able to breach host defenses, oviposit, and reproduce. Mountain pine beetles and Hymenopteran parasitoids share some biological features, the most notable of which is obligatory host death as a consequence of parasitoid attack and development. We developed spatiotemporal models of mountain pine beetle dynamics that were based on the Nicholson-Bailey framework but which featured beetle aggregation and a tree-level attack threshold. By fitting our models to data from a local mountain pine beetle outbreak, we demonstrate that due to aggregation, attack thresholds at the tree level can be overcome by a surprisingly low ratio of beetles per susceptible tree at the stand level. This results confirms the importance of considering aggregation in models of organisms that are subject to strong Allee effects.

The changing trend in nitrate concentrations in major aquifers due to historical nitrate loading from agricultural land across England and Wales from 1925 to 2150

Nitrate is necessary for agricultural productivity, but can cause considerable problems if released into aquatic systems. Agricultural land is the major source of nitrates in UK groundwater. Due to the long time-lag in the groundwater system, it could take decades for leached nitrate from the soil to discharge into freshwaters. However, this nitrate time-lag has rarely been considered in environmental water management. Against this background, this paper presents an approach to modelling groundwater nitrate at the national scale, to simulate the impacts of historical nitrate loading from agricultural land on the evolution of groundwater nitrate concentrations. An additional process-based component was constructed for the saturated zone of significant aquifers in England and Wales. This uses a simple flow model which requires modelled recharge values, together with published aquifer properties and thickness data. A spatially distributed and temporally variable nitrate input function was also introduced. The sensitivity of parameters was analysed using Monte Carlo simulations. The model was calibrated using national nitrate monitoring data. Time series of annual average nitrate concentrations along with annual spatially distributed nitrate concentration maps from 1925 to 2150 were generated for 28 selected aquifer zones. The results show that 16 aquifer zones have an increasing trend in nitrate concentration, while average nitrate concentrations in the remaining 12 are declining. The results are also indicative of the trend in the flux of groundwater nitrate entering rivers through baseflow. The model thus enables the magnitude and timescale of groundwater nitrate response to be factored into source apportionment tools and to be taken into account alongside current planning of land-management options for reducing nitrate losses.

Contaminant profiles for surface water, sediment, flora and fauna associated with the mangrove fringe along middle and lower eastern Tampa Bay

Contaminant concentrations are reported for surface water, sediment, flora and fauna collected during 2010-2011 from the mangrove fringe along eastern Tampa Bay, Florida. Concentrations of trace metals, chlorinated pesticides, atrazine, total polycyclic aromatic hydrocarbons, and polychlorinated biphenyls were species-, chemical- and location-specific. Contaminants in sediments did not exceed proposed individual sediment quality guidelines. Most sediment quality assessment quotients were less than one indicating the likelihood of no inhibitory effect based on chemical measurements alone. Faunal species typically contained more contaminants than plant species; seagrass usually contained more chemicals than mangroves. Bioconcentration factors for marine angiosperms were usually less than 10 and ranged between 1 and 31. Mercury concentrations (ppm) in blue crabs and fish did not exceed the U.S. Environmental Protection Agency fish tissue criterion of 0.3 and the U.S. Food and Drug Administration action level of 1.0. In contrast, total mercury concentrations in faunal species often exceeded guideline values for wildlife consumers of aquatic biota.

Urinary tract effects of HPSE2 mutations

Urofacial syndrome (UFS) is an autosomal recessive congenital disease featuring grimacing and incomplete bladder emptying. Mutations of HPSE2, encoding heparanase 2, a heparanase 1 inhibitor, occur in UFS, but knowledge about the HPSE2 mutation spectrum is limited. Here, seven UFS kindreds with HPSE2 mutations are presented, including one with deleted asparagine 254, suggesting a role for this amino acid, which is conserved in vertebrate orthologs. HPSE2 mutations were absent in 23 non-neurogenic neurogenic bladder probands and, of 439 families with nonsyndromic vesicoureteric reflux, only one carried a putative pathogenic HPSE2 variant. Homozygous Hpse2 mutant mouse bladders contained urine more often than did wild-type organs, phenocopying human UFS. Pelvic ganglia neural cell bodies contained heparanase 1, heparanase 2, and leucine-rich repeats and immunoglobulin-like domains-2 (LRIG2), which is mutated in certain UFS families. In conclusion, heparanase 2 is an autonomic neural protein implicated in bladder emptying, but HPSE2 variants are uncommon in urinary diseases resembling UFS.

The protective effect of antioxidants to a phototoxin-sensitive insect herbivore,Manduca sexta

Photo-activated plant secondary compounds have been shown to be toxic to many organisms including insects. Insect defenses include behavioral mechanisms such as light avoidance, as well as specific biochemical defenses such as antioxidants and antioxidant enzymes. These antioxidant defenses eliminate or quench the deleterious singlet oxygen and free radicals formed by these phototoxins. In this paper we examined the role of dietary antioxidants in protecting the phototoxin-sensitive insect herbivoreManduca sexta. Elevated dietary levels of the lipid-soluble antioxidantsΒ-carotene and vitamin E resulted in a concentration-dependent reduction in the mortality associated with treatment ofM. sexta larvae with the phototoxic thiopheneα-terthienyl. Elevated levels of dietary ascorbic acid had no effect, whereas reduced levels greatly increased the toxicity ofα-terthienyl. Tissue levels of antioxidants were shown to increase substantially in larvae fed antioxidant-supplemented diets. The results suggest that the ability to absorb and utilize plant-derived antioxidants could be an important defense against photo-activated plant secondary compounds and may have allowed some insects to exploit phototoxic plants.

Pitpnm1 is expressed in hair cells during development but is not required for hearing

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We studied the expression of Pitpnm1 in the developing mouse inner ear.

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We covered several ages between E14.5 and P5, and also looked at adults.

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Pitpnm1 is expressed in the inner hair cells from before birth to adulthood.

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Pitpnm1 is expressed transiently in the outer hair cells at early postnatal stages.

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Mice lacking Pitpnm1 display no obvious auditory defects.

Deafness is a genetically complex disorder with many contributing genes still unknown. Here we describe the expression of Pitpnm1 in the inner ear. It is expressed in the inner hair cells of the organ of Corti from late embryonic stages until adulthood, and transiently in the outer hair cells during early postnatal stages. Despite this specific expression, Pitpnm1 null mice showed no hearing defects, possibly due to redundancy with the paralogous genes Pitpnm2 and Pitpnm3.

Development and psychometric evaluation of the public health surveillance well-being scale

PURPOSE

To develop and psychometrically evaluate the brief Public Health Surveillance Well-Being Scale (PHS-WB) that captures mental, physical, and social components of well-being.

METHODS

Using data from 5,399 HealthStyles survey respondents, we conducted bi-factor, item response theory, and differential item functioning analyses to examine the psychometric properties of a pool of 34 well-being items. Based on the statistical results and content considerations, we developed a brief 10-item well-being scale and assessed its construct validity through comparisons of demographic subgroups and correlations with measures of related constructs.

RESULTS

Based on the bi-factor analyses, the items grouped into both an overall factor and individual domain-specific factors. The PHS-WB scale demonstrated good internal consistency (alpha = 0.87) and correlated highly with scores for the entire item pool (r = 0.94). The well-being scale scores differed as expected across demographic groups and correlated with global and domain-specific measures of similar constructs, supporting its construct validity.

CONCLUSION

The 10-item PHS-WB scale demonstrates good psychometric properties, and its high correlation with the item pool suggests minimal loss of information with the use of fewer items. The brief PHS-WB allows for well-being assessment on national surveys or in other situations where a longer form may not be feasible.

Improvement in the renal prognosis in nephropathic cystinosis

BACKGROUND AND OBJECTIVES

Nephropathic cystinosis (NC) is an autosomal recessive disorder occurring in one to two per 100,000 newborns. Because of the rarity of NC, long-term outcome data are scarce.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

245 NC patients from 18 countries provided data to the ESPN/ERA-EDTA registry. We matched NC patients on renal replacement therapy (RRT) to non-NC children on RRT.

RESULTS

Between 1979 and 2008, mean age at the start of RRT among NC children increased by 0.15 year per calendar year (95% confidence interval, 0.10 to 0.21) from 8.8 to 12.7 years, whereas we did not observe this in non-NC children. Five-year survival after the start of RRT improved in NC patients from 86.1% (before 1990) to 100% (since 2000) as compared with the control population (89.6% and 94.0%). NC patients received a renal allograft more often (relative risk, 1.09; 95% confidence interval, 1.00 to 1.17) as compared with matched RRT children, and 5-year graft survival was better (94.0% versus 84.0%). NC dialysis patients were less often hypertensive than non-NC children matched for age, country, and dialysis modality (42.7% versus 51.7%) and had lower parathyroid hormone levels (median, 56 versus 140 pg/ml). Although height at start of RRT slightly improved during the past decade, children with NC remained significantly shorter than non-NC children at the start of RRT.

CONCLUSIONS

We demonstrated improved survival of the renal function as well as better patient and graft survival after the start of RRT in a large European cohort of NC patients over the last two decades.

Antithymocyte treatment of steroid-resistant acute rejection in renal transplantation

To evaluate the outcome of early (ER <3 months) and late (LR >3 months) episodes of corticosteroid resistant acute allograft rejection (CRR) treated with anti-thymocyte globulin (ATG) in pediatric renal allograft recipients. Retrospective study of 15 children, mean age 13.2 y, who received ATG for the treatment of biopsy proven CRR over a 15 year period. Seven children received ATG for ER (median 26 days post transplantation) and 8 for LR (median 763 days). There was a significant improvement in the 3 month eGFR (70.3 ml/min/1.73m(2), SD 22.3, p = 0.018) when compared with the value prior to ATG treatment (23.3 ml/min/1.73m(2), SD 10.2) in the ER group. In the LR group (4 DSA positive) there was no improvement in the eGFR at 3 months (42 ml/min/1.73m(2), SD 10.5, p = 0.32) when compared with the value prior to ATG (38 ml/min/1.73 m(2), SD 9.7). At final review, eGFR in the ER group was 72.3 ml/min/1.73m(2) (SD 33) vs. 37.7 ml/min/1.73m(2) (SD 17.9) in the LR group after a mean follow up of 10.4 y and 1.2 y, respectively. ATG therapy in CRR is associated with reversal of rejection and excellent graft outcome in children with ER. The benefits remain uncertain in LR, the etiology of which is multifactorial.

Identification of Candida species in formalin fixed, paraffin wax embedded oral mucosa by sequencing of ribosomal DNA

Aim-To identify Candida species in formalin fixed, paraffin wax embedded tissue by sequencing candidal rDNA.Methods-Target rDNA sequences were amplified by polymerase chain reaction (PCR) from fresh isolates of Candida and from 18 preserved oral mucosal tissue samples (16 cases of chronic hyperplastic candidiasis and two fibroepithelial polyps), shown histologically to contain Candida. Identification of Candida species within tissue was based on a comparison of the rDNA sequences obtained with those from the fresh isolates of Candida and those present in the GenBank database.Results-The PCR products obtained from 12 of the 18 tissue specimens studied were characteristic of Candida albicans. In two of these cases a second, larger PCR product was obtained and these sequences were characteristic of Candida glabrata.Conclusions-Candidal DNA was amplified successfully from formalin fixed, paraffin wax embedded tissue. Sequencing of the PCR product enabled identification of the Candida species present.

Intravenous methylprednisolone in idiopathic childhood nephrotic syndrome

The aim of our study was to determine the clinical course of children with idiopathic childhood nephrotic syndrome (ICNS) who received intravenous methylprednisolone (ivMP) following failure to achieve remission with standard oral prednisolone therapy. This study was designed as a retrospective case record review from 1993 to 2007. Sixteen children received ivMP over the 15-year study period, of whom ten responded, achieving clinical remission. The remaining six children with steroid resistant nephrotic syndrome (SRNS) underwent biopsy [four focal segmental glomerulosclerosis (FSGS), two minimal change disease (MCD)]. Three responders developed late secondary steroid resistance (two FSGS, one MCD). At the latest follow-up (mean 6.7 years), three of the ten ivMP responders and none (0/6) of the children with SRNS had heavy proteinuria and chronic kidney disease (CKD) stage 3-5. The remaining 13 children demonstrated significant steroid dependency but had achieved stable remission following cyclophosphamide and/or ciclosporin therapy. The majority of children with ICNS who do not respond to 4 weeks of daily prednisolone therapy will enter remission following three to five doses of ivMP, thus avoiding a renal biopsy at initial presentation. These children are likely to develop steroid dependency, and the majority will require treatment with alkylating agents and/or ciclosporin to maintain remission. The requirement for ivMP in this setting appears to be associated with a risk of developing CKD in the longer term.

Determinants of eGFR at start of renal replacement therapy in paediatric patients

BACKGROUND

Few studies have investigated the determinants of glomerular filtration rate (GFR) in paediatric patients starting on dialysis or with a transplant.

METHODS

Data were collected as part of the European Society of Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association registry from 14 European countries and referred to incident paediatric patients starting on renal replacement therapy (RRT) between 2002 and 2007 under the age of 18 years. Estimated glomerular filtration rate (eGFR) was calculated using the Schwartz formula. Data were adjusted for age, gender, treatment modality at start, primary cause of renal failure (PRD) and regions in Europe (eGFR(adj)).

RESULTS

Median eGFR in the 938 patients starting RRT was 10.4 mL/min/1.73 m(2) (5th and 95th percentile: 4.0-26.9). Twenty-six patients (2.8%), mainly infants with Finnish-type nephropathy, started with eGFR levels >50 mL/min/1.73 m(2). Younger age, female gender, starting on dialysis and having a short time between the first visit to a paediatric nephrologist (PN) and start of RRT were associated with lower eGFR at start of RRT. Gender differences were only present during adolescent age and disappeared when using the same K value for both genders. The various PRDs showed large differences in the rate of decline in eGFR between the first visit to a PN and start of RRT; however, this did not result in differences in eGFR(adj) at start of RRT.

CONCLUSIONS

The main determinants of eGFR at start of RRT were age, gender, treatment modality at start, and the time between the first visit to a PN and start of RRT. Research is needed to determine the consequences of these differences.

UK Renal Registry 12th Annual Report (December 2009): chapter 14: demography of the UK paediatric renal replacement therapy population in 2008

AIMS

To describe the demographics of the paediatric RRT population in the UK and analyse changes in demographics with time.

METHODS

Extraction and analysis of data from the UK Paediatric Renal Registry and the UK Renal Registry (UKRR).

RESULTS

The UK paediatric established renal failure (ERF) population in December 2008 was 905 patients. The prevalence under the age of 16 years was 56 per million age related population (pmarp) and the incidence 7.4 pmarp. The incidence and prevalence for South Asian patients was much higher than that of the White and Black populations. Renal dysplasia was the most common cause of ERF accounting for 33% of prevalent cases. Diseases with autosomal recessive inheritance were a common cause of ERF in all ethnic groups, 23.5% of prevalent and 18% of incident cases. Whilst the incidence and prevalence of diseases with autosomal recessive inheritance in the South Asian population was 3 times that of the white population, this was not the sole reason for the increased proportion of South Asian patients with ERF, as diseases with no defined inheritance were twice as common in this ethnic group than in White patients. Prevalent mortality stood at 9.4%. Most deaths were in patients presenting with ERF early in life and mortality varied markedly according to the aetiology of ERF. The proportion with new grafts from living donors has steadily risen to 54%. Children from ethnic minority groups were less likely to have an allograft and living donation was less frequent in this population. For those on dialysis, 56% were receiving peritoneal dialysis. This was the main treatment modality for patients under 4 years of age.

CONCLUSIONS

The paediatric ERF population continued to expand slowly. Incidence and prevalence rates were stable and similar to other developed nations. The high incidence in patients from ethnic minority groups will lead to a greater proportion of the population being from these groups in time. To maintain the high proportion of engrafted patients it will be necessary to encourage living donation in the ethnic minority population. Case note analysis of the factors involved in mortality would be valuable.

Pattern formation in prey-taxis systems

In this paper, we consider spatial predator-prey models with diffusion and prey-taxis. We investigate necessary conditions for pattern formation using a variety of non-linear functional responses, linear and non-linear predator death terms, linear and non-linear prey-taxis sensitivities, and logistic growth or growth with an Allee effect for the prey. We identify combinations of the above non-linearities that lead to spatial pattern formation and we give numerical examples. It turns out that prey-taxis stabilizes the system and for large prey-taxis sensitivity we do not observe pattern formation. We also study and find necessary conditions for global stability for a type I functional response, logistic growth for the prey, non-linear predator death terms, and non-linear prey-taxis sensitivity.

UK Renal Registry 11th Annual Report (December 2008): Chapter 13 Demography of the UK paediatric renal replacement therapy population

AIMS

To describe the demographics of the paediatric RRT population in the UK and analyse changes in demographics with time.

METHODS

Extraction and analysis of data from the UK paediatric Renal Registry.

RESULTS

The UK paediatric established renal failure (ERF) population in April 2008 was 875 patients. The prevalence under the age of 16 years was 55 per million age related population (pmp) and the incidence 7.92 pmp. The incidence and prevalence for South Asian and Other ethnic groups were 3 times that of the White and Black populations. Renal dysplasia was the most common cause of ERF accounting for 33% of prevalent cases. Diseases with autosomal recessive inheritance were more common in patients from ethnic minority groups. The spectrum of diseases seen has changed over a generation. Overall 5 year survival for children with ERF was 91.8%. Five year survival of infants starting dialysis was just 62%. Transplanted patients accounted for 74% of the current population. The proportion with grafts from living donors has steadily risen to 34%. Children from ethnic minority groups were less likely to have an allograft and living donation was less frequent in this population. For those on dialysis, 57% were receiving peritoneal dialysis. This was the main treatment modality for patients under 4 years of age.

CONCLUSIONS

The paediatric ERF population continued to expand slowly. Incidence and prevalence rates were stable and similar to other developed nations. The high incidence in patients from ethnic minority groups will lead to a greater proportion of the population being from these groups in time. To maintain the high proportion of engrafted patients it will be necessary to encourage living donation in the ethnic minority population. The spectrum of diseases seen has already changed over a generation with the treatment of young children with diseases such as congenital nephrosis. The incidence of cystinosis causing ERF was reduced, probably reflecting better early treatment.

Successful renal transplantation in children in the presence of thrombosis of the inferior vena cava

Thrombosis of the inferior vena cava (IVC) has previously been considered to be a contraindication to renal transplantation in children because of the technical difficulties associated with surgery and the increased risk of graft thrombosis. We report three children with previous IVC thrombosis who underwent renal transplantation at our institution over the last 5 years. The pretransplant imaging of these patients included direct venography or magnetic resonance venography to evaluate venous outflow. Two children (19 kg and 36 kg) received deceased donor renal allografts with no surgical complications or delayed graft function. At the latest follow-up 3.0 and 4.6 years posttransplantation, respectively, they were well, with estimated glomerular filtration rates of 52 and 64 ml/min per 1.73 m(2), respectively. The third child underwent a live-related-donor renal transplant at the age of 4.9 years (weight 13.5 kg). There was primary graft nonfunction. Renal vein thrombosis was noted on postoperative day 12, with subsequent graft loss. Children with previous IVC thrombosis can be successfully transplanted with adult-sized kidneys provided detailed evaluation of the venous drainage has been performed. There is substantial risk of graft thrombosis, and detailed counselling regarding the specific risks of the procedure is essential.

On net reproductive rate and the timing of reproductive output

Abstract: Understanding the relationship between life-history patterns and population growth is central to demographic studies. Here we derive a new method for calculating the timing of reproductive output, from which the generation time and its variance can also be calculated. The method is based on the explicit computation of the net reproductive rate (R0) using a new graphical approach. Using nodding thistle, desert tortoise, creeping aven, and cat's ear as examples, we show how R0 and the timing of reproduction is calculated and interpreted, even in cases with complex life cycles. We show that the explicit R0 formula allows us to explore the effect of all reproductive pathways in the life cycle, something that cannot be done with traditional analysis of the population growth rate (lambda). Additionally, we compare a recently published method for determining population persistence conditions with the condition R0 > 1 and show how the latter is simpler and more easily interpreted biologically. Using our calculation of the timing of reproductive output, we illustrate how this demographic measure can be used to understand the effects of life-history traits on population growth and control.

Allee effects, invasion pinning, and species' borders

All species' ranges are the result of successful past invasions. Thus, models of species' invasions and their failure can provide insight into the formation of a species' geographic range. Here, we study the properties of invasion models when a species cannot persist below a critical population density known as an "Allee threshold." In both spatially continuous reaction-diffusion models and spatially discrete coupled ordinary-differential-equation models, the Allee effect can cause an invasion to fail. In patchy landscapes (with dynamics described by the spatially discrete model), range limits caused by propagation failure (pinning) are stable over a wide range of parameters, whereas, in an uninterrupted habitat (with dynamics described by a spatially continuous model), the zero velocity solution is structurally unstable and thus unlikely to persist in nature. We derive conditions under which invasion waves are pinned in the discrete space model and discuss their implications for spatially complex dynamics, including critical phenomena, in ecological landscapes. Our results suggest caution when interpreting abrupt range limits as stemming either from competition between species or a hard environmental limit that cannot be crossed: under a wide range of plausible ecological conditions, species' ranges may be limited by an Allee effect. Several example systems appear to fit our general model.

Storage of household firearms: an examination of the attitudes and beliefs of married women with children

Although safe firearm storage is a promising injury prevention strategy, many parents do not keep their firearms unloaded and locked up. Using the theory of planned behavior as a guiding conceptual framework, this study examines factors associated with safe storage among married women with children and who have firearms in their homes. Data come from a national telephone survey (n=185). We examined beliefs about defensive firearm use, subjective norms, perceived behavioral control and firearm storage practices. A Wilcoxon-Mann-Whitney test was conducted to assess associations between psychosocial factors and firearm storage practices. Women were highly motivated to keep firearms stored safely. Those reporting safe storage practices had more favorable attitudes, more supportive subjective norms and higher perceptions of behavioral control than those without safe storage. One-fourth believed a firearm would prevent a family member from being hurt in case of a break-in, 58% believed a firearm could scare off a burglar. Some 63% said they leave decisions about firearm storage to their husbands. Women were highly motivated to store firearms safely as evidenced by favorable attitudes, supportive subjective norms and high perceptions of behavioral control. This was especially true for those reporting safer storage practices.

Demography of renal disease in childhood

The demography of renal failure in childhood is examined through an analysis of the UK Renal Registry data on patients in established renal failure (ERF) and studies of chronic kidney disease populations. The predominant cause is renal dysplasia and related conditions. Congenital obstructive uropathy is the third largest group overall and the second in early childhood. Males predominate in both these groups. Antenatal diagnoses are frequently not made despite routine scanning. Those children, who present to nephrology after the age of 3 months without an antenatal diagnosis, progress to ERF later than those diagnosed antenatally. Discrepancies exist between the demography of antenatal diagnoses and those seen postnatally. This is likely to represent the limitations of antenatal ultrasound as a diagnostic screening tool.

Patient perceptions about illness self-management in ANCA-associated small vessel vasculitis

OBJECTIVES

To characterize patient perceptions, related to eight self-management behaviours relevant for adults with ANCA-associated small vessel vasculitis (ANCA-SVV), and to determine if these perceptions were associated with performance of each behaviour.

METHODS

Adults with ANCA-SVV (n = 202) completed a self-administered questionnaire that assessed eight self-management behaviours (adherence to recommendations for medication, health service use, diet, exercise, infection avoidance and symptom monitoring; prompt reporting of symptoms and side effects; and adjusting activities in response to symptoms), perceptions about these behaviours, socio-demographics, clinical factors and social desirability bias. Descriptive statistics were generated to characterize patients' perceptions about difficulty of, importance of, and specific barriers to performing each behaviour. Regression analyses explored whether these variables were associated with performing each behaviour, controlling for potential confounders.

RESULTS

With few exceptions, higher perceived importance and lower perceived difficulty of each behaviour were associated with more frequent performance of the behaviour. For each behaviour, several specific barriers were frequently endorsed by patients and a number of these were associated with lower levels of self-management.

CONCLUSION

This study reveals that patient perceptions about the illness and its treatment influence ANCA-SVV self-management. Perceived barriers to medication, health services, diet and exercise adherence were similar to those in other illnesses. This study also provides insight into barriers experienced by patients in performing behaviours (infection avoidance, symptom monitoring, reporting symptoms and side-effects and adjusting activities) not often previously studied. How the identification of these barriers can help inform future interventions for ANCA-SVV patients is to be discussed.

Cardiovascular outcomes among sildenafil users: results of the International Men's Health Study

AIM

To assess the incidence of serious cardiovascular disease (CVD) events [i.e. myocardial infarction (MI) and stroke] and all-cause mortality in men with erectile dysfunction (ED) who received prescriptions for sildenafil.

METHODS

The International Men's Health Study (IMHS) was a prospective, observational cohort study of patients with ED and a new or existing prescription for sildenafil. Baseline and follow-up questionnaires provided information on demographics, CVD risk factors and ED. Postevent questionnaires were mailed to patients following possible nonfatal CVD events to collect information related to exposure to sildenafil/ED treatments before the event.

RESULTS

Thirty-five CVD events were reported in 30 patients in the analysis set (n = 3813). The incidence of all-cause mortality, MI and stroke was 0.4, 0.6 and 0.1 per 100 patient-years of observation respectively. Among the six men who reported using sildenafil in the month before a nonfatal CVD event, two reported use in the 24 h before the event.

CONCLUSION

The results of the IMHS support previous reports that ED and CVD are often comorbid and share risk factors.

Probabilistic neural networks modeling of the 48-h LC50 acute toxicity endpoint to Daphnia magna

Two modeling experiments based on the maximum likelihood estimation paradigm and targeting prediction of the Daphnia magna 48-h LC50 acute toxicity endpoint for both organic and inorganic compounds are reported. The resulting models computational algorithms are implemented as basic probabilistic neural networks with Gaussian kernel (statistical corrections included). The first experiment uses strictly D. magna information for 971 structures as training/learning data and the resulting model targets practical applications. The second experiment uses the same training/learning information plus additional data on another 29 compounds whose endpoint information is originating from D. pulex and Ceriodaphnia dubia. It only targets investigation of the effect of mixing strictly D. magna 48-h LC50 modeling information with small amounts of similar information estimated from related species, and this is done as part of the validation process. A complementary 81 compounds dataset (involving only strictly D. magna information) is used to perform external testing. On this external test set, the Gaussian character of the distribution of the residuals is confirmed for both models. This allows the use of traditional statistical methodology to implement computation of confidence intervals for the unknown measured values based on the models predictions. Examples are provided for the model targeting practical applications. For the same model, a comparison with other existing models targeting the same endpoint is performed.

Outcome of Henoch-Schönlein purpura nephritis treated with long-term immunosuppression

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 long-term 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 end-stage 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.

Complex spatial group patterns result from different animal communication mechanisms

We present previously undescribed spatial group patterns that emerge in a one-dimensional hyperbolic model for animal group formation and movement. The patterns result from the assumption that the interactions governing movement depend not only on distance between conspecifics, but also on how individuals receive information about their neighbors and the amount of information received. Some of these patterns are classical, such as stationary pulses, traveling waves, ripples, or traveling trains. However, most of the patterns have not been reported previously. We call these patterns zigzag pulses, semizigzag pulses, breathers, traveling breathers, and feathers.

Accuracy of ultrasonic detection of renal scarring in different centres using DMSA as the gold standard

BACKGROUND

There is an ongoing debate over the radiological investigations of children with urinary tract infections (UTIs) with some authorities suggesting that ultrasound scan (USS) alone is an accurate tool to diagnose renal parenchymal scarring post-pyelonephritis. All studies on this subject have been performed at paediatric teaching centres whereas most children with UTIs are managed by General Paediatricians in District General Hospitals (DGHs) in the United Kingdom. We wished to identify whether results of scans in DGHs differed from those in teaching centres.

METHODS

We looked at all children with a clinical history of UTIs having a DMSA and USS over a one year period in two DGHs and one teaching centre. A total of 476 children's results were reviewed, 297 from the DGHs and 179 from the teaching centre.

RESULTS

The cohort had a total of 949 renal units. There were 79 scarred renal units (kidneys) on DMSA (8%) in 72 patients (15%). Just 18 renal units were detected as being scarred on USS (22.8%). Nine of 32 scarred renal units in the teaching centre were detected compared with nine of 47 in the DGHs (P = 0.40). Thirty-nine (49%) of the scarred renal units were in patients >5-years old. Of these 12 (30.7%) were detected on USS, nine of 17 within the teaching centre compared with just three of 22 at the DGHs (P = 0.01).

CONCLUSION

Overall only a small percentage of scars are detected on USS. In the over 5-year old group, where USS alone might be preferred, DGHs were significantly worse at detecting scarred kidneys. We conclude that if the detection of renal scars is a prime reason for imaging in children with UTIs, ultrasonography alone is inappropriate at any age and DMSA ought to be the primary investigation.

Biological Control Through Intraguild Predation: Case Studies in Pest Control, Invasive Species and Range Expansion

Intraguild predation (IGP), the interaction between species that eat each other and compete for shared resources, is ubiquitous in nature. We document its occurrence across a wide range of taxonomic groups and ecosystems with particular reference to non-indigenous species and agricultural pests. The consequences of IGP are complex and difficult to interpret. The purpose of this paper is to provide a modelling framework for the analysis of IGP in a spatial context. We start by considering a spatially homogeneous system and find the conditions for predator and prey to exclude each other, to coexist and for alternative stable states. Management alternatives for the control of invasive or pest species through IGP are presented for the spatially homogeneous system. We extend the model to include movement of predator and prey. In this spatial context, it is possible to switch between alternative stable steady states through local perturbations that give rise to travelling waves of extinction or control. The direction of the travelling wave depends on the details of the nonlinear intraguild interactions, but can be calculated explicitly. This spatial phenomenon suggests means by which invasions succeed or fail, and yields new methods for spatial biological control. Freshwater case studies are used to illustrate the outcomes.

A new method for calculating net reproductive rate from graph reduction with applications to the control of invasive species

Matrix models are widely used for demographic analysis of age and stage structured biological populations. Dynamic properties of the model can be summarized by the net reproductive rate R (0). In this paper, we introduce a new method to calculate and analyze the net reproductive rate directly from the life cycle graph of the matrix. We show, with examples, how our method of analysis of R (0) can be used in the design of strategies for controlling invasive species.

Modeling Group Formation and Activity Patterns in Self-Organizing Collectives of Individuals

We construct and analyze a nonlocal continuum model for group formation with application to self-organizing collectives of animals in homogeneous environments. The model consists of a hyperbolic system of conservation laws, describing individual movement as a correlated random walk. The turning rates depend on three types of social forces: attraction toward other organisms, repulsion from them, and a tendency to align with neighbors. Linear analysis is used to study the role of the social interaction forces and their ranges in group formation. We demonstrate that the model can generate a wide range of patterns, including stationary pulses, traveling pulses, traveling trains, and a new type of solution that we call zigzag pulses. Moreover, numerical simulations suggest that all three social forces are required to account for the complex patterns observed in biological systems. We then use the model to study the transitions between daily animal activities that can be described by these different patterns.

National survey of doses from CT in the UK: 2003

A review of patient doses from CT examinations in the UK for 2003 has been conducted on the basis of data received from over a quarter of all UK scanners, of which 37% had multislice capability. Questionnaires were employed to collect scan details both for the standard protocols established at each scanner for 12 common types of CT examination on adults and children, and for samples of individual patients. This information was combined with published scanner-specific CT dose index (CTDI) coefficients to estimate values of the standard dose indices CTDI(w) and CTDI(vol) for each scan sequence. Knowledge of each scan length allowed assessment of the dose-length product (DLP) for each examination, from which effective doses were then estimated. When compared with a previous UK survey for 1991, wide variations were still apparent between CT centres in the doses for standard protocols. The mean UK doses for adult patients were in general lower by up to 50% than those for 1991, although doses were slightly higher for multislice (4+) (MSCT) relative to single slice (SSCT) scanners. Values of CTDI(vol) for MSCT were broadly similar to European survey data for 2001. The third quartile values of these dose distributions have been used to derive UK national reference doses for examinations on adults (separately for SSCT and MSCT) and children as initial tools for promoting patient protection. The survey has established the PREDICT (Patient Radiation Exposure and Dose in CT) database as a sustainable national resource for monitoring dose trends in CT through the ongoing collation of further survey data.

Diabetes mellitus following paediatric renal transplantation: a single centre experience

BACKGROUND/AIMS

Post-transplant diabetes mellitus (PTDM) has a variably reported incidence of 4-41% among adults and children. We describe our recent experience of four children with PTDM in a paediatric renal transplantation centre.

METHODS

We undertook a retrospective analysis of the glycaemic status of all paediatric patients undergoing renal transplantation at our centre in the 2-year study period. The clinical features and investigations of those who developed PTDM were further reviewed.

RESULTS

Five episodes of PTDM occurred in 4/32 children. There was a variable onset and a wide range of symptoms. Investigations revealed a combination of insulinopenia with peripheral insulin resistance. Insulin therapy was required for variable durations with resolution of PTDM in four episodes. PTDM did not adversely affect the renal graft function.

CONCLUSION

PTDM requires increased awareness among paediatric nephrologists and endocrinologists for early recognition and prompt effective intervention.

An evaluation of the quality of commercially produced patient information leaflets

AIM

A descriptive study was undertaken to assess the quality of a range of patient information leaflets produced by the British Dental Association.

METHOD

Twenty-nine leaflets were assessed with regard to presentation, readability and quality. The topic areas covered included: treatment, self-care and disease related information. Presentation was evaluated with regard to layout, font size, typeface, use of illustrations, paper type and print colour. Readability was assessed using the Flesch reading grade and the SMOG reading grade. Quality was assessed using the DISCERN tool.

FINDINGS

All leaflets scored quite well for readability, with the average SMOG Reading Grade Level being 9.10 (SD 0.80) and the average Flesch reading Grade Level being 6.18 (SD 0.83). There were, however, some areas of presentation that could be improved, specifically font size, illustration use and paper finish, which did not comply with the RNIB guidelines. Quality ratings using the DISCERN tool were low. In particular most leaflets scored poorly in setting out clear aims in the opening paragraph, in identifying sources and dates of information provided, and other sources of advice and support available. Few leaflets discussed the option of no treatment or how the treatment would affect overall quality of life. The role of shared decision making was rarely mentioned.

CONCLUSION

Patient information leaflets produced commercially are of high production quality and good readability but tend not to be patient centred.

Nurse bullying: organizational considerations in the maintenance and perpetration of health care bullying cultures

AIM

To examine bullying within nursing from a micro-sociological perspective and elucidate interactive mechanisms contributing to its causes and continuation within the nursing profession.

BACKGROUND

The paper is part of a doctoral research study into bullying within nursing. It considers issues pertinent to management, and in the role of negotiated interactions within the National Health Service when dealing with bullying problems. The complex dynamics involved can be problematic for management when dealing with bullying, while often managers have been targets of bullying themselves and not infrequently accused of it. Features of bullying activity are explored, along with issues of target and bully awareness, a central feature in bullying negotiations. Issues of awareness and emergence of bullying behaviour have been identified through vignettes and unstructured interviews, and the research has identified complex interactive events in the creation and maintenance of nurse bullying activity. It is hoped that with a clearer understanding of such mechanisms and manifestations that bullying in the workplace can be reduced or eliminated. The paper is of practical use to nurse managers in illuminating such mechanisms and bringing bullying awareness to the fore. Such activity is ultimately damaging to the organization in both cost and time; and significant for professional practice by its impact upon the nurse and their work in supportive and safe environments. It will also to allow managers to consider their own practice and reactions to bullying activity within the profession.

CONCLUSIONS

The overall findings from the research point strongly to bullying activity being essentially 'learned behaviour' within the workplace rather than any predominantly psychological deficit within individual perpetrators and targets.

Potential role of natural enemies during tree range expansions following climate change

Recent investigations have shown how chance, long-range dispersal events can allow tree populations to migrate rapidly in response to changes in climate. However, this apparent solution to Reid's paradox applies solely within the context of single species models, while the rapid migration rates seen in pollen records occurred within multispecies communities. Ecologists are therefore presented with a new challenge: reconciling the macroscopic dynamics of spread seen in the pollen record with the rules and interactions governing plant community assembly. A case that highlights this issue is the rapid spread of Beech during the Holocene into a landscape already dominated by a close competitor, Hemlock. In this study, we analyse a simple model of plant community assembly incorporating competition for space and dispersal dynamics, showing how, even when a species is capable of rapid migration into an empty landscape, the presence of an ecologically similar competitor causes Reid's paradox to re-emerge because of the dramatic slowing effect of competitive interactions on a species' rate of spread. We then show how the answer to the question of how tree species dispersed rapidly into occupied landscapes may lie in secondary interactions with host-specific pathogens and parasites. Inclusion of host-specific pathogens into the simple community assembly model illustrates how tree species undergoing range expansions can temporarily outstrip specialist predators, giving rise to a transient Jansen-Connell effect, in which the invader acts as temporary 'super-species' that spreads rapidly into communities already occupied by competitors at rates consistent with those observed in the paleo-record.

Sustained correction of glycogen storage disease type II using adeno-associated virus serotype 1 vectors

Glycogen storage disease type II (GSDII) is caused by a lack of functional lysosomal acid alpha-glucosidase (GAA). Affected individuals store glycogen in lysosomes beginning during gestation, ultimately resulting in fatal hypertrophic cardiomyopathy and respiratory failure. We have assessed the utility of recombinant adeno-associated virus (rAAV) vectors to restore GAA activity in vivo in a mouse model of GSDII (Gaa(-/-)). A single systemic administration of a rAAV serotype 1 (rAAV1) vector to neonate animals resulted in restored cardiac GAA activity to 6.4 times the normal level (mean=641+/-190% of normal (Gaa(+/+)) levels with concomitant glycogen clearance) at 11 months postinjection. Greater than 20% of normal levels of GAA activity were also observed in the diaphragm and quadriceps muscles. Furthermore, functional correction of the soleus skeletal muscle was also observed compared to age-matched untreated Gaa(-/-) control animals. These results demonstrate that rAAV1 vectors can mediate sustained therapeutic levels of correction of both skeletal and cardiac muscles in a model of fatal cardiomyopathy and muscular dystrophy.

Percutaneous real-time ultrasound-guided renal biopsy by automated biopsy gun in children: safety and complications

BACKGROUND

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.

METHODS

Retrospective case note review.

RESULTS

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 patients developed urinary retention requiring catheterization for up to 48 hours post-procedure, two of whom also had macroscopic hematuria. Pain post procedure was reported in 7.6% episodes and was reported significantly more often with elective native biopsies.

CONCLUSIONS

Renal biopsy can safely be performed as a day care procedure, if patients are observed for six hours instead of 24-hours post biopsy.

Long-term outcome of meningococcal sepsis-associated acute renal failure

SETTING

Twenty-one of 209 children admitted to the intensive care unit with meningococcal septicemia developed oliguric acute renal failure necessitating renal replacement therapy.

PATIENTS

Twelve survivors underwent renal assessment at a median of 4.2 yrs postpresentation.

RESULT

Two had abnormal glomerular filtration rate, proteinuria, and hypertension; one had isolated proteinuria; and one had an isolated renal parenchymal defect on DMSA scan.

CONCLUSION

Long-term follow-up of this population is recommended.

Hormone replacement therapy: pathobiological aspects of hormone-sensitive cancers in women relevant to epidemiological studies on HRT: a mini-review

Hormone replacement therapy (HRT) has gained widespread and in some areas indiscriminate use. In reference to recent epidemiological studies which showed unexpected and controversial associations of HRT use with malignant tumours, here we review the current understanding of the dynamics of tumour growth. The pathomorphological characteristics and sex hormone sensitivity of cancers of the breast, endometrium, ovary and colon are discussed. The development of cancer from the first malignant tumour cell to clinical diagnosis takes many years. Hormones can influence tumour growth, but it is questionable whether hormones induce malignant tumours de novo. It is much more likely that hormones 'merely' promote the growth of already existing tumour cells. The long developmental process of tumours is in apparent contradiction to results of some epidemiological studies that describe an increased cancer risk, implying primary initiation, in HRT users within observation periods of 1-6 years. The mechanisms of initiation versus promotion of hormone-sensitive cancers, particularly breast cancer, are only partly understood. The conventional methods of epidemiological studies cannot detect potential risk factors without bias if they do not include a pathomorphological component on growth characteristics. The results of previous studies should be interpreted with great caution with regard to tumour biology.

Persistence, spread and the drift paradox

We derive conditions for persistence and spread of a population where individuals are either immobile or dispersing by advection and diffusion through a one-dimensional medium with a unidirectional flow. Reproduction occurs only in the stationary phase. Examples of such systems are found in rivers and streams, marine currents, and areas with prevalent wind direction. In streams, a long-standing question, dubbed 'the drift paradox', asks why aquatic insects faced with downstream drift are able to persist in upper stream reaches. For our two-phase model, persistence of the population is guaranteed if, at low population densities, the local growth rate of the stationary component of the population exceeds the rate of entry of individuals into the drift. Otherwise the persistence condition involves all the model parameters, and persistence requires a critical (minimum) domain size. We calculate the rate at which invasion fronts propagate up- and downstream, and show that persistence and ability to spread are closely connected: if the population cannot advance upstream against the flow, it also cannot persist on any finite spatial domain. By studying two limiting cases of our model, we show that residence in the immobile state always enhances population persistence. We use our findings to evaluate a number of mechanisms previously proposed in the ecological literature as resolutions of the drift paradox.