Bending the rules: exploitation of allochthonous resources by a top-predator modifies size-abundance scaling in stream food webs.

Body mass-abundance (M-N) allometries provide a key measure of community structure, and deviations from scaling predictions could reveal how cross-ecosystem subsidies alter food webs. For 31 streams across the UK, we tested the hypothesis that linear log-log M-N scaling is shallower than that predicted by allometric scaling theory when top predators have access to allochthonous prey. These streams all contained a common and widespread top predator (brown trout) that regularly feeds on terrestrial prey and, as hypothesised, deviations from predicted scaling increased with its dominance of the fish assemblage. Our study identifies a key beneficiary of cross-ecosystem subsidies at the top of stream food webs and elucidates how these inputs can reshape the size-structure of these 'open' systems.

Hepatic Changes in the Fontan Circulation: Identification of Liver Dysfunction and an Attempt to Streamline Follow-up Screening.

We tried to identify structural and functional liver aberrances in a palliated Fontan population and sought to determine useful screening modalities, in order to propose a screening protocol to detect patients at risk. Twenty nine patients, median age 23.7 years (interquartile range (IQR) 20.5-27.2) and median Fontan interval 19.7 years (IQR 4.5-21.4), were prospectively studied with echocardiography, blood analysis (including serum fibrosis scores Forns, APRI and FIB4), liver imaging (ultrasound (US), Doppler), and shear wave elastography to determine liver stiffness (LS). Laboratory tests predominantly showed abnormal values for gamma-glutamyltransferase. Forns index indicated moderate fibrosis in 29% of patients and correlated with Fontan interval (p = 0.034). US liver morphology was deviant in 46% of patients, with surface nodularity in 21% and nodular hyperplasia in 29%. Doppler assessment of flow velocities was within normal ranges for most patients. LS (mean 10.4 ± 3.7 kPa) was elevated in 96% of our population and higher LS values were significantly related to longer Fontan interval (p = 0.018). Adolescent and adult Fontan patients show moderate signs of liver dysfunction. Usefulness of serum parameters and fibrosis scores in post-Fontan screening remains ambiguous. The high percentage of morphologic liver changes in palliated patients supports the use of US in periodic follow-up. LS likely overestimates fibrosis due to liver congestion, arguing for the need of validation through sequential measurements. Screening should minimally encompass US assessment in combination with selective liver fibrosis scores. The role of LS measurement in Fontan follow-up and liver screening needs to be further elucidated.

Modalities and prescribing strategies in intensive home hemodialysis: a narrative review.

Over the past decades, evidence on the benefits of intensive hemodialysis, more frequent and longer comparing to conventional hemodialysis, has emerged. The home environment is an ideal setting to perform intensive hemodialysis without the reliance on organizational and structural needs. The observed benefits of frequent hemodialysis have resulted in a rise in prevalent intensive home hemodialysis patients around the world. A successful home hemodialysis program requires a well-structured predialysis education program with focus on home dialysis and a dedicated multidisciplinary team with knowledge about the specifics of home hemodialysis and with a holistic approach to provide optimal care. In this narrative review, we describe different modalities of home hemodialysis and dialysis prescription specifics of intensive nocturnal hemodialysis, the modality with overall best outcomes.

Potential of carbohydrate-binding agents as therapeutics against enveloped viruses.

Twenty-seven years after the discovery of HIV as the cause of AIDS more than 25 drugs directed against four different viral targets (i.e. reverse transcriptase, protease, integrase, envelope gp41) and one cellular target (i.e. CCR5 co-receptor) are available for treatment. However, the search for an efficient vaccine is still ongoing. One of the main problems is the presence of a continuously evolving dense carbohydrate shield, consisting of N-linked glycans that surrounds the virion and protects it against efficient recognition and persistent neutralization by the immune system. However, several lectins from the innate immune system specifically bind to these glycans in an attempt to process the virus antigens to provoke an immune response. Across a wide variety of different species in nature lectins can be found that can interact with the glycosylated envelope of HIV-1 and can block the infection of susceptible cells by the virus. In this review, we will give an overview of the lectins from non-mammalian origin that are endowed with antiviral properties and discuss the complex interactions between lectins of the innate immune system and HIV-1. Also, attention will be given to different carbohydrate-related modalities that can be exploited for antiviral chemotherapy.

How does handwashing behaviour change in response to a cholera outbreak? A qualitative case study in the Democratic Republic of the Congo.

BACKGROUND: Handwashing with soap has the potential to curb cholera transmission. This research explores how populations experienced and responded to the 2017 cholera outbreak in the Democratic Republic of the Congo and how this affected their handwashing behaviour. METHODS: Cholera cases were identified through local cholera treatment centre records. Comparison individuals were recruited from the same neighbourhoods by identifying households with no recent confirmed or suspected cholera cases. Multiple qualitative methods were employed to understand hand hygiene practices and their determinants, including unstructured observations, interviews and focus group discussions. The data collection tools and analysis were informed by the Behaviour Centred Design Framework. Comparisons were made between the experiences and practices of people from case households and participants from comparison households. RESULTS: Cholera was well understood by the population and viewed as a persistent and common health challenge. Handwashing with soap was generally observed to be rare during the outbreak despite self-reported increases in behaviour. Across case and comparison groups, individuals were unable to prioritise handwashing due to competing food-scarcity and livelihood challenges and there was little in the physical or social environments to cue handwashing or make it a convenient, rewarding or desirable to practice. The ability of people from case households to practice handwashing was further constrained by their exposure to cholera which in addition to illness, caused profound non-health impacts to household income, productivity, social status, and their sense of control. CONCLUSIONS: Even though cholera outbreaks can cause disruptions to many determinants of behaviour, these shifts do not automatically facilitate an increase in preventative behaviours like handwashing with soap. Hygiene programmes targeting outbreaks within complex crises could be strengthened by acknowledging the emic experiences of the disease and adopting sustainable solutions which build upon local disease coping mechanisms.

Food web complexity and allometric scaling relationships in stream mesocosms: implications for experimentation.

1. Mesocosms are used extensively by ecologists to gain a mechanistic understanding of ecosystems based on the often untested assumption that these systems can replicate the key attributes of natural assemblages. 2. Previous investigations of stream mesocosm utility have explored community composition, but here for the first time, we extend the approach to consider the replicability and realism of food webs in four outdoor channels (4 m(2)). 3. The four food webs were similarly complex, consisting of diverse assemblages (61-71 taxa) with dense feeding interactions (directed connectance 0.09-0.11). Mesocosm food web structural attributes were within the range reported for 82 well-characterized food webs from natural streams and rivers. When compared with 112 additional food webs from standing freshwater, marine, estuarine and terrestrial environments, stream food webs (including mesocosms) had similar characteristic path lengths, but typically lower mean food chain length and exponents for the species-link relationship. 4. Body size (M) abundance (N) allometric scaling coefficients for trivariate taxonomic mesocosm food webs (-0.53 to -0.49) and individual size distributions (-0.60 to -0.58) were consistent and similar to those from natural systems, suggesting that patterns of energy flux between mesocosm consumers and resources were realistic approximations. 5. These results suggest that stream mesocosms of this scale can support replicate food webs with a degree of biocomplexity that is comparable to 'natural' streams. The findings highlight the potential value of mesocosms as model systems for performing experimental manipulations to test ecological theories, at spatiotemporal scales of relevance to natural ecosystems.

Environmental DNA provides higher resolution assessment of riverine biodiversity and ecosystem function via spatio-temporal nestedness and turnover partitioning.

Rapidly assessing biodiversity is essential for environmental monitoring; however, traditional approaches are limited in the scope needed for most ecological systems. Environmental DNA (eDNA) based assessment offers enhanced scope for assessing biodiversity, while also increasing sampling efficiency and reducing processing time, compared to traditional methods. Here we investigated the effects of landuse and seasonality on headwater community richness and functional diversity, via spatio-temporal dynamics, using both eDNA and traditional sampling. We found that eDNA provided greater resolution in assessing biodiversity dynamics in time and space, compared to traditional sampling. Community richness was seasonally linked, peaking in spring and summer, with temporal turnover having a greater effect on community composition compared to localized nestedness. Overall, our assessment of ecosystem function shows that community formation is driven by regional resource availability, implying regional management requirements should be considered. Our findings show that eDNA based ecological assessment is a powerful, rapid and effective assessment strategy that enables complex spatio-temporal studies of community diversity and ecosystem function, previously infeasible using traditional methods.

Patterns of invertebrate functional diversity highlight the vulnerability of ecosystem services over a 45-year period.

Declines in invertebrate biodiversity1,2 pose a significant threat to key ecosystem services.3-5 Current analyses of biodiversity often focus on taxonomic diversity (e.g., species richness),6,7 which does not account for the functional role of a species. Functional diversity of species' morphological or behavioral traits is likely more relevant to ecosystem service delivery than taxonomic diversity, as functional diversity has been found to be a key driver of a number of ecosystem services including decomposition and pollination.8-12 At present, we lack a good understanding of long-term and large-scale changes in functional diversity, which limits our capacity to determine the vulnerability of key ecosystem services with ongoing biodiversity change. Here we derive trends in functional diversity and taxonomic diversity over a 45-year period across Great Britain for species supporting freshwater aquatic functions, pollination, natural pest control, and agricultural pests (a disservice). Species supporting aquatic functions showed a synchronous collapse and recovery in functional and taxonomic diversity. In contrast, pollinators showed an increase in taxonomic diversity, but a decline and recovery in functional diversity. Pest control agents and pests showed greater stability in functional diversity over the assessment period. We also found that functional diversity could appear stable or show patterns of recovery, despite ongoing changes in the composition of traits among species. Our results suggest that invertebrate assemblages can show considerable variability in their functional structure over time at a national scale, which provides an important step in determining the long-term vulnerability of key ecosystem services with ongoing biodiversity change.

Persistent left superior vena cava (PLSVC) connected to the left atrium.

A persistent left superior vena cava draining into the left atrium was diagnosed in an adult patient, scheduled for surgical correction of a large inferiorly located sinus venosus atrial septal defect. In the majority of cases a persistent left superior vena cava is found incidentally and causes little or no symptoms. Nevertheless, anaesthesiologist should be aware of its occurrence; because of different technical difficulties and clinical problems that can be encountered. Echocardiography plays an key role in the detection of a persistent left superior vena cava.

Microdeletion of the entire IRF6 gene in a Subsaharian African's family with Van der Woude syndrome.

Microdeletion of the entire interferon regulatory factory 6 (IRF 6) gene is a rare cause of Van der Woude syndrome (VDW) with only few cases reported in medical literature. Its occurrence in multiple affected members of a family is exceptional. The aim of this presentation was to describe a Central African family with typical VDW phenotype carrying an IRF6 gene deletion. Here we reported phenotype features of members of a Central African family with VDW syndrome consisting of labioalveolar cleft, depressions of the lower lip with labial fistulae (lip pits), submucosal clefts and cleft palate. Mutation analysis by means of multiplex ligation-dependent probe amplification and chromosomal microarray revealed a 374.070 kb, deletion encompassing the entire IRF6 gene in four affected family members. Microdeletion of the entire IRF6 gene causes the classical VDW syndrome phenotype.

Executing multi-taxa eDNA ecological assessment via traditional metrics and interactive networks.

Current approaches to ecological assessment are limited by the traditional morpho-taxonomic methods presently employed and the inability to meet increasing demands for rapid assessments. Advancements in high throughput sequencing now enable rapid high-resolution ecological assessment using environmental DNA (eDNA). Here we test the ability of using eDNA-based ecological assessment methods against traditional assessment of two key indicator groups (diatoms and macroinvertebrates) and show how eDNA across multiple gene regions (COI, rbcL, 12S and 18S) can be used to infer interactive networks that link to ecological assessment criteria. We compared results between taxonomic and eDNA based assessments and found significant positive associations between macroinvertebrate (p < 0.001 R2 = 0.645) and diatom (p = 0.015, R2 = 0.222) assessment metrics. We further assessed the ability of eDNA based assessment to identify environmentally sensitive genera and found an order of magnitude greater potential for 18S, versus COI or rbcL, to determine environmental filtering of ecologically assessed communities. Lastly, we compared the ability of traditional metrics against co-occurrence network properties of our combined 18S, COI and rbcL indicator genera to infer habitat quality measures currently used by managers. We found that transitivity (network connectivity), linkage density and cohesion were significantly associated with habitat modification scores (HMS), whereas network properties were inconsistent with linking to the habitat quality score (HQS) metric. The incorporation of multi-marker eDNA network assessment opens up a means for finer scale ecological assessment, currently limited using traditional methods. While utilization of eDNA-based assessment is recommended, direct comparisons with traditional approaches are difficult as the methods are intrinsically different and should be treated as such with regards to future research. Overall, our findings show that eDNA can be used for effective ecological assessment while offering a wider range of scope and application compared to traditional assessment methods.

First Case of COVID-19-Associated Collapsing Glomerulopathy in Sub-Saharan Africa.

Although the lungs remain the main target of SARS-CoV-2, other organs, such as kidneys, can be affected, which has a negative impact on the outcomes of COVID-19 patients. Although previous studies of kidney disease in COVID-19 reported mainly SARS-CoV-2-induced tubular and interstitial injury, there is growing evidence coming out of Africa of glomerular involvement, especially collapsing glomerulopathy seen particularly in people of African descent. We report a case of collapsing glomerulopathy revealed by acute kidney injury and a new onset of full blown nephrotic syndrome in a black Congolese patient coinfected with COVID-19 and malaria.

What Works? the Influence of Changing Wastewater Treatment Type, Including Tertiary Granular Activated Charcoal, on Downstream Macroinvertebrate Biodiversity Over Time.

The present study reviewed the impacts of wastewater on macroinvertebrates over 4 decades in a United Kingdom lowland river. This involved examining changes in chemicals, temperature, flow, and macroinvertebrate diversity from the 1970s until 2017 for a wastewater-dominated river downstream of Swindon in the United Kingdom (population ~ 220 000). When the wastewater treatment process changed from trickling filter to activated sludge in 1991, biological oxygen demand was nearly halved (90th percentile from 8.1 to 4.6 mg/L), ammonia peaks dropped more than 7-fold (90th percentile from 3.9 to 0.53 mg/L), whereas dissolved oxygen climbed consistently above 60% saturation (10th percentile from 49 to 64%) at a sampling point 2 km downstream of the wastewater treatment plant. A sustained increase in the number of macroinvertebrate species was evident from that point. River flow did not change, temperature rose slightly, and the major metal concentrations declined steadily over most of the monitoring period. Neither the introduction of phosphate stripping in 1999 nor the use of tertiary granular activated charcoal from 2008 to 2014 had strong positive effects on subsequent macroinvertebrate diversity. That the diversity still had not reached the ideal status by 2016 may be related to the modest habitat quality, agricultural pesticides, and limited recolonization potential in the catchment. The results indicate that urban wastewaters, with their chemical pollutants, are today probably not the biggest threat to the macroinvertebrate diversity of multiply stressed lowland rivers in the United Kingdom. Environ Toxicol Chem 2019;38:1820-1832. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Patient doses in radiographic examinations in 12 countries in Asia, Africa, and Eastern Europe: initial results from IAEA projects.

OBJECTIVE: The purpose of this study was to survey image quality and the entrance surface air kerma for patients in radiographic examinations and to perform comparisons with diagnostic reference levels. SUBJECTS AND METHODS: In this multinational prospective study, image quality and patient radiation doses were surveyed in 12 countries in Africa, Asia, and Eastern Europe, covering 45 hospitals. The rate of unsatisfactory images and image quality grade were noted, and causes for poor image quality were investigated. The entrance surface doses for adult patients were determined in terms of the entrance surface air kerma on the basis of X-ray tube output measurements and X-ray exposure parameters. Comparison of dose levels with diagnostic reference levels was performed. RESULTS: The fraction of images rated as poor was as high as 53%. The image quality improved up to 16 percentage points in Africa, 13 in Asia, and 22 in Eastern Europe after implementation of a quality control (QC) program. Patient doses varied by a factor of up to 88, although the majority of doses were below diagnostic reference levels. The mean entrance surface air kerma values in mGy were 0.33 (chest, posteroanterior), 4.07 (lumbar spine, anteroposterior), 8.53 (lumbar spine, lateral), 3.64 (abdomen, anteroposterior), 3.68 (pelvis, anteroposterior), and 2.41 (skull, anteroposterior). Patient doses were found to be similar to doses in developed countries and patient dose reductions ranging from 1.4% to 85% were achieved. CONCLUSION: Poor image quality constitutes a major source of unnecessary radiation to patients in developing countries. Comparison with other surveys indicates that patient dose levels in these countries are not higher than those in developed countries.

Phosphorus and nitrogen limitation and impairment of headwater streams relative to rivers in Great Britain: A national perspective on eutrophication.

This study provides a first national-scale assessment of the nutrient status of British headwater streams within the wider river network, by joint analysis of the national Countryside Survey Headwater Stream and Harmonised River Monitoring Scheme datasets. We apply a novel Nutrient Limitation Assessment methodology to explore the extent to which nutrients may potentially limit primary production in headwater streams and rivers, by coupling ternary assessment of nitrogen (N), phosphorus (P), and carbon (C) depletion, with N:P stoichiometry, and threshold P and N concentrations. P limitation was more commonly seen in the rivers, with greater prevalence of N limitation in the headwater streams. High levels of potential P and N co-limitation were found in the headwater streams, especially the Upland-Low-Alkalinity streams. This suggests that managing both P and N inputs may be needed to minimise risks of degradation of these sensitive headwater stream environments. Although localised nutrient impairment of headwater streams can occur, there were markedly lower rates of P and N impairment of headwater streams relative to downstream rivers at the national scale. Nutrient source contributions, relative to hydrological dilution, increased with catchment scale, corresponding with increases in the extent of agricultural and urban land-use. The estimated nutrient reductions needed to achieve compliance with Water Framework Directive standards, and to reach limiting concentrations, were greatest for the Lowland-High-Alkalinity rivers and streams. Preliminary assessments suggest that reducing P concentrations in the Lowland-High-Alkalinity headwater streams, and N concentrations in the Upland-Low-Alkalinity rivers, might offer greater overall benefits for water-quality remediation at the national scale, relative to the magnitude of nutrient reductions required. This approach could help inform the prioritisation of nutrient remediation, as part of a directional approach to water quality management based on closing the gaps between current and target nutrient concentrations.

Non-syndromic cleft lip and/or cleft palate: Epidemiology and risk factors in Lubumbashi (DR Congo), a case-control study.

PURPOSE: To determine the incidence and risk factors of occurrence of non-syndromic cleft lip and/or cleft palate (NSCLP) in Lubumbashi. METHOD: A case-control study was conducted in the health district of Lubumbashi from February 2012 to December 2015. An exhaustive sampling, collecting all newborns with cleft lip and/or cleft palate (CL ± P) in maternity wards was conducted. From a total of 172 cases, 162 non-syndromic cases were recruited. For each case, one clinically normal newborn control was selected. RESULTS: NSCLP had an incidence of 1/1258 live births (0.8/1000). We found significant associations with a family history of cleft lip and palate (CLP) (x2family history = 11.5, p = 0.0007), maternal alcohol intake (OR = 19.3, 95% CI: 1.9-197.1), paternal alcohol during the periconceptional period and the first trimester of pregnancy (OR = 18.7, 95% CI: 3.9-89.2), maternal educational level lower than high school (OR = 9.5, 95% CI: 2.0-44.7), clay (Pemba) consumption during pregnancy (OR = 38.3, 95% CI: 9.3-157.0), the use of insecticides in the evening (OR = 130.3, 95% CI: 13.2-1286.9), indoor cooking with charcoal (Makala) (OR = 6.5, 95% CI: 1.22-34.5), and regular consumption of Kapolowe fish, supposedly contaminated with heavy metals (OR = 29.5, 95% CI: 7.4-116.7). CONCLUSION: Several environmental risk factors highly prevalent in Central Africa for facial clefting were found.

Effect of environmental parameters (temperature, pH and a(w)) on the individual cell lag phase and generation time of Listeria monocytogenes.

The effect of the individual environmental factors temperature (2-30 degrees C), pH (4.4-7.4) and a(w) (0.947-0.995) as well as the combinations of these factors on the individual cell lag phase and the generation time of Listeria monocytogenes was investigated. Individual cells were isolated using a serial dilution protocol in microtiter plates, and subsequent growth was investigated by optical density (OD) measurements at 600 nm. About 100 replicates were made for each set of environmental conditions. Part of the data were previously published in Francois et al. (Francois, K., Devlieghere, F., Smet, K., Standaert, A.R., Geeraerd, A.H., Van Impe, J.F., Debevere, J., 2005a. Modelling the individual cell lag phase: effect of temperature and pH on the individual cell lag distribution of Listeria monocytogenes. Int. J. Food Microbiol. 100, 41-53.), but were recalculated here using the calibration curves for transformation of optical density to colony forming units/ml from Francois et al. (Francois, K., Devlieghere, F., Standaert, A.R., Geeraerd, A.H., Cools, I., Van Impe, J.F., Debevere, J., 2005b. Environmental factors influencing the relationship between optical density and cell count for Listeria monocytogenes. J. Appl. Microbiol. 99, 1503-1515), as this calibration curve appeared to be dependent on the environmental parameters. The previous dataset was also extended with a factor a(w), observed individually and combinations with the above mentioned environmental factors. Individual cell lag phases and subsequent growth rates were calculated assuming an exponential growth model. The results are discussed as mean values to determine the general trends and in addition, histograms are made and statistical distributions are fitted to the different data sets. When stress levels increased, the mean values and the variability observed for the individual cell lag phases increased, resulting in broader histograms and distributions that were shifting to the right. Also the gravity point of the distributions was shifting from a skewed left type to a more symmetrical type. The best description of the data is obtained with an exponential distribution for low stress levels, a gamma distribution for intermediate stress and a Weibull distribution for severe stress levels. When only low stress levels were applied, a significant percentage of the cells showed no lag phase. In those cases, a new approach was used to obtain better fits: cells with a lag phase and those without a lag phase were separated using a binomial distribution while in a second step, a gamma or a Weibull distribution is fitted to the fraction of cells showing a lag phase. A normal distribution is used to describe the variability of the generation times. These distributions can be applied to refine the exposure assessment part of the risk assessment concerning L. monocytogenes by incorporating intercellular variability.

Modelling the individual cell lag phase: effect of temperature and pH on the individual cell lag distribution of Listeria monocytogenes.

The individual-based approach of the lag phase is gaining interest, especially for pathogens that initially contaminate food products in low amounts. In this paper, the effect of temperature (30, 10, 7, 4 and 2 degrees C) and pH (7.4, 6.1, 5.5, 5.0, 4.7 and 4.4) on the individual cell lag phase of Listeria monocytogenes was examined in a factorial design, using OD measurements. Individual lag phases of about 100 individual cells per condition were examined and calculated using a linear extrapolation method. Generation times were calculated out of the slope. The obtained data were analyzed at three different levels: in a first approach, the mean values were calculated for each set of environmental conditions and compared to predictions made by the USDA's Pathogen Modeling Program (PMP) for analogous growth conditions. The PMP predictions of the generation times were in the same order of magnitude as the obtained data, although a persistent underestimation could be observed. The observed individual cell lag data differed from lag phase predictions by PMP. Possible reasons for this discrepancy are discussed. Secondly, histograms of individual lag phase measurements were constructed for the different temperature-pH combinations. In this way, the influence of both factors on the variability of individual lag phases could be estimated. At low stress levels, most individual cells showed a short lag phase resulting in a compression of the histograms at the zero-lag level, while, at high stress levels, the histograms shifted to longer lag phases with a significant increase in variability. Thirdly, 37 different distribution types were fitted to the datasets to reveal the distributions that fitted best the obtained data. The gamma distribution was preferred at moderate stress levels, while the Weibull distribution was chosen for harsher growth conditions.

Obtaining single cells: analysis and evaluation of an experimental protocol by means of a simulation model.

The research presented in this paper analyses a newly developed experimental protocol for isolating single cells by constructing a simulation model of the process. The protocol involves sequential 50% dilutions of a cell suspension in a microtiter plate, so that eventually, wells are obtained containing exactly one cell. The aim of this modelling study is (i) to gain insight in the governing mechanisms of the dilution process, (ii) to confirm experimental findings and (iii) to enable the prediction of an average outcome for future experiments. The model construction process is presented chronologically. The initial basic model simulates the experiment as a sequence of binomial processes, using Monte Carlo techniques. Statistical analysis of the results shows that aggregational factors need to be taken into account in the form of a lognormal distribution. Several issues involved in this adaptation are discussed. To fully account for cell aggregation in the dilution process, a cell clumping algorithm is built into the simulation model. Simulation data from the resulting model show similar statistical characteristics as the experimental data and yield reliable prediction intervals for the available experimental data. The simulation model is a useful tool to support experimental findings and predict the outcome of future experiments. Even more importantly, this study emphasises the importance of careful statistical analysis in single cell research. The impact of stochastic effects is considerably amplified at the low cell concentrations involved and needs to be taken into account in any modelling effort.

Closure of atrial septal defects: is there still a place for surgery?

BACKGROUND: The purpose of this study is to assess the current management of atrial septal defect closure in an era of increasing feasibility of transcatheter device occlusion. METHODS: Atrial septal defect (ASD) closure was performed surgically through complete sternotomy in 165 patients (group 1) and through partial inferior sternotomy in 53 patients (group 2). Transcatheter device occlusion was achieved in 82 patients with only ASD type II and patent foramen ovale (group 3). RESULTS: Overall complications were minor and more frequent in group 1: 26.7% versus 13.2% in group 2 and 14.6% in group 3 (p = 0.04). Compared to complete sternotomy, a partial sternotomy led to less chest tube loss (7.1 +/- 2.9 versus 11.6 +/- 14.5 ml/kg) (p < 0.05) and less postoperative pericardial effusion (11.3% versus 13.5%)(p = 0.55). ASD closure was effective in 99.4% in group 1, 100% in group 2 but only in 86.6% in group 3 (p < 0.05). Two major complications of device implantation required early surgery: 1 femoral arteriovenous fistula and 1 device embolization. Hospital stay was significantly shorter in group 3, as well as in group 2 compared to group 1 (8.3 +/- 4.2 versus 5.9 +/- 1.1 versus 2.1 +/- 7.3 days) (p < 0.05). Midterm results were excellent, with only 1 non-cardiac death and 1 re-operation for residual shunt in group 1, and 1 device removal for thrombosis in group 3. CONCLUSION: Transcatheter device occlusion has become an established treatment for ASD closure, achieving optimal results in older children and adults with anatomically suited ASD type II and PFO. However, a partial inferior sternotomy offers a valuable and complementary operative approach for all ASD variants, maintaining the predictable success of surgery, with the obvious advantages of minimal access in terms of morbidity, cosmetics and hospital stay.