[Differential diagnosis and treatment of hyponatremia]

Hyponatremia is one of the most common metabolic disorders in clinical medicine. The value of Na+ in serum equalling 135 mmol/ l and lower is regarded as hyponatremia. Its clinical manifestations are the following: headaches, nausea, vomiting, seizures, numbness, coma and death. Hyponatremia caused by nonosmotic hypersecretion of vasopressin can be divided into: a) hypovolemic, b) normovolemic and c) hypervolemic. Hyponatremia which is not caused by the hypersecretion of vasopressin is the so  called pseudohyponatremia, water intoxication, cerebral salt loss syndrome. Hypovolemic hyponatremia is caused by the loss of Na+ and fluid loss from the organism. It occurs, for example, after using thiazide diuretics, after recurrent diarrhoea, vomiting, after significant blood loss and other causes. Treatment of this disorder must focus on the producing cause and on the parenteral administration of 0.9% NaCl. Normovolemic hyponatremia can be with or without symptoms. Acute normovolemic hyponatremia is treated by the intravenous administration of 3% NaCl and with the simultaneous use of loop diuretics (20- 40 mg Furosemide/ 24 hrs) and restriction of fluid intake. In the case of chronic normovolemic hyponatremia, refractory to the previous treatment, caused by the inappropriate secretion of arginine  vasopressin, it is recommended to use perorally its V2- receptor blocker, Tolvaptan. Hypervolemic hyponatremia occurs in the case of cardiovascular failure, with hepatic cirrhosis, nephrotic syndrome, renal failure, porphyric disease and other conditions. Symptoms occurring with it are swellings, ascites, distension of jugular veins and the presence of unaccented rales in the lungs, which can be detected during physical examination. For treatment it is recommended to restrict fluid intake and to administer NaCl as well as diuretic therapy. Recently it has been recommended to use Tolvaptan which increases excretion of free water (aquaresis), decreases osmolality in the urine, and leads to the increase in serum Na+. Apart from that, we present our three clinical  laboratory observations in the paper: 1. Contrary to the data in the literature, after the Košice Marathon (42.125 km) the serum concentration of Na+ in the runners increased (from 144.4 ± 2.1 mmol/ l to 147 ± 2.8 mmol/ l, p < 0.01) in spite of a significant reduction in the body weight (from 73.2 ± 5.7 kg to 71.9 ± 5.2 kg, p < 0.05), intensive perspiration and dehydration (blood haemoglobin before the run: 150.4 ± 5.5 g/ l, after the run: 152.1 ± 4.8 g/ l, p < 0.05). Apart from that, we detected a significant decrease in the fractional excretion of sodium (FENa) from 1.16 ± 0.30% to 0.34 ± 0.10%, p < 0.01. 2. One patient with chronic intermittent porphyria displayed the syndrome of inappropriate antidiuretic hormone secretion, which had been positively influenced by the restriction of fluid intake in the long term and by peroral administration of 1- 3 g NaCl/ 24 hrs. 3. In 15 haemodialysed patients with chronic renal failure, who displayed recurrent hypervolemic hyponatremia, we achieved, by means of adequate ultrafiltration and a dialysis solution containing Na+ 145 mmol/ l, the serum concentration of Na+ 142 mmol/ l at the end of haemodialysis.

Highways versus pipelines: contributions of two fungal transport mechanisms to efficient bioremediation

Based on experimental studies, two different fungus-mediated transport mechanisms have been suggested to facilitate the bacterial degradation of organic soil pollutants: bacteria may use liquid films around fungal hyphae for quick dispersal ('fungal highways'), and fungi may take up and translocate pollutants through their mycelial network ('fungal pipelines'). Both mechanisms are anticipated to enhance the bioavailability of pollutants to degrading bacteria. Using a microbial simulation model, we therefore investigated their respective efficiency in increasing biodegradation performance. We analysed networks that act either as bacterial dispersal vectors or as pollutant translocation vectors or as a combination of both. Our results suggest that each mechanism can improve biodegradation performance. The degree of improvement, however, varies distinctly depending on the environmental conditions, and is even negligible under certain conditions. Mycelial networks acting as 'highways' allow bacteria to overcome motility restrictions and reach remote areas, whereas networks acting as 'pipelines' may initiate degradation by bringing remote pollutants to bacteria. As a consequence, highest biodegradation improvements often emerge from the combination of both mechanisms. We conclude that 'fungal highways' as well as 'fungal pipelines' should be considered for developing novel bioremediation strategies based on fungus-mediated transport in soils.

The relevance of conditional dispersal for bacterial colony growth and biodegradation

Bacterial degradation is an ecosystem service that offers a promising method for the remediation of contaminated soils. To assess the dynamics and efficiency of bacterial degradation, reliable microbial simulation models, along with the relevant processes, are required. We present an approach aimed at improving reliability by studying the relevance and implications of an important concept from theoretical ecology in the context of a bacterial system: conditional dispersal denoting that the dispersal strategy depends on environmental conditions. Different dispersal strategies, which either incorporate or neglect this concept, are implemented in a bacterial model and results are compared to data obtained from laboratory experiments with Pseudomonas putida colonies growing on glucose agar. Our results show that, with respect to the condition of resource uptake, the model's correspondence to experimental data is significantly higher for conditional than for unconditional bacterial dispersal. In particular, these results support the hypothesis that bacteria disperse less when resources are abundant. We also show that the dispersal strategy has a considerable impact on model predictions for bacterial degradation of resources: disregarding conditional bacterial dispersal can lead to overestimations when assessing the performance of this ecosystem service.

Dispersal networks for enhancing bacterial degradation in heterogeneous environments

Successful biodegradation of organic soil pollutants depends on their bioavailability to catabolically active microorganisms. In particular, environmental heterogeneities often limit bacterial access to pollutants. Experimental and modelling studies revealed that fungal networks can facilitate bacterial dispersal and may thereby improve pollutant bioavailability. Here, we investigate the influence of such bacterial dispersal networks on biodegradation performance under spatially heterogeneous abiotic conditions using a process-based simulation model. To match typical situations in polluted soils, two types of abiotic conditions are studied: heterogeneous bacterial dispersal conditions and heterogeneous initial resource distributions. The model predicts that networks facilitating bacterial dispersal can enhance biodegradation performance for a wide range of these conditions. Additionally, the time horizon over which this performance is assessed and the network's spatial configuration are key factors determining the degree of biodegradation improvement. Our results support the idea of stimulating the establishment of fungal mycelia for enhanced bioremediation of polluted soils.

Breaking functional connectivity into components: a novel approach using an individual-based model, and first outcomes

Landscape connectivity is a key factor determining the viability of populations in fragmented landscapes. Predicting 'functional connectivity', namely whether a patch or a landscape functions as connected from the perspective of a focal species, poses various challenges. First, empirical data on the movement behaviour of species is often scarce. Second, animal-landscape interactions are bound to yield complex patterns. Lastly, functional connectivity involves various components that are rarely assessed separately. We introduce the spatially explicit, individual-based model FunCon as means to distinguish between components of functional connectivity and to assess how each of them affects the sensitivity of species and communities to landscape structures. We then present the results of exploratory simulations over six landscapes of different fragmentation levels and across a range of hypothetical bird species that differ in their response to habitat edges. i) Our results demonstrate that estimations of functional connectivity depend not only on the response of species to edges (avoidance versus penetration into the matrix), the movement mode investigated (home range movements versus dispersal), and the way in which the matrix is being crossed (random walk versus gap crossing), but also on the choice of connectivity measure (in this case, the model output examined). ii) We further show a strong effect of the mortality scenario applied, indicating that movement decisions that do not fully match the mortality risks are likely to reduce connectivity and enhance sensitivity to fragmentation. iii) Despite these complexities, some consistent patterns emerged. For instance, the ranking order of landscapes in terms of functional connectivity was mostly consistent across the entire range of hypothetical species, indicating that simple landscape indices can potentially serve as valuable surrogates for functional connectivity. Yet such simplifications must be carefully evaluated in terms of the components of functional connectivity they actually predict.

[Respiratory therapy (bagging, air stacking) for patients in early neurorehabilitation]

In a pilot project we examined whether an improvement of oxygen saturation (SPO (2)) can be established by applying a modified respiratory intervention technique (bagging) for patients in early neurorehabilitation. The "bagging" method involves adding air into the lungs during the inspiration phase by using a resuscitation bag. Subsequently, the patient is requested to cough, and is given manual support on the chest by the therapist. We examined a group of 11 patients who received 1 - 2 bagging interventions per day over a period of 12 days. By applying the bagging method, a continuous and stable improvement of oxygen saturation could be accomplished for all patients. A single case analysis confirmed this effect for each patient. Furthermore, we observed an improvement of the patients' vigilance, improved quality of bronchial secretion and marked improvements in swallowing and phonation. The bagging method is an easy-to-learn and inexpensive method that leads to a stable and sustained increase in oxygen saturation and to improvement of other clinical parameters.

System for time resolved spectral studies of pulsed atmospheric discharges in the visible to vacuum ultraviolet range

Vacuum ultraviolet (VUV) emission is believed to play a major role in the development of plasma streamers in pulsed atmospheric discharges, but detection of VUV light is difficult in pulsed experiments at atmospheric pressures. Since VUV light is absorbed in most standard optical materials as well, careful attention must be given to the selection of the lens and mirror optics used in these studies. Of highest interest is the VUV emission during the initial stage of pulsed atmospheric discharges, which has a typical duration in the nanosecond regime. An experiment was designed to study this fast initial stage of VUV emission coupled with fast optical imaging of streamer propagation, both with temporal resolution on the order of nanoseconds. A repetitive solid-state high voltage pulser was constructed which produces triggered flashover discharges with low jitter and consistent pulse amplitude. VUV emission is captured utilizing both photomultiplier and intensified charge-coupled device detectors during the fast stage of streamer propagation. These results are discussed in context with the streamer formation photographed in the visible wavelength regime with 3 ns exposure time.

[Examples for asbestos-related findings in HRCT - criteria for the assessment of causal relationships in surveillance programmes and medical expert opinion]

The increasing use of high-resolution computed tomography in formerly asbestos-exposed workers requires valid diagnostic criteria for the findings which have to be reported as suspicious for being asbestos-related in surveillance programmes and for the assessment of causal relationships between former asbestos exposure and findings in computed tomography. The present article gives examples for asbestos-related findings in HR-CT and discusses the specificity of parenchymal and pleural changes due to asbestos fibres.

[Recommendations for reporting benign asbestos-related findings in chest X-ray and CT to the accident insurances]

Asbestos-related diseases still play an important role in occupational medicine. The detection of benign asbestos-related diseases is one condition for the compensation of asbestos-related lung cancer in Germany. Due to the increasing use of computed tomography, asbestos-related diseases are more frequently detected in the early stages. The present article proposes recommendations for the findings which have to be reported as suspicious for being asbestos-related based on a) chest X-rays and b) computed tomography using the International Classification System for Occupational and Environmental Respiratory Diseases (ICOERD).

Wastewater treatment modelling in practice: a collaborative discussion of the state of the art

Three consulting teams conducted independent modelling projects for three different wastewater treatment plants ranging in size from approximately 113,800 m(3)/d (30 mgd) to 530,000 m(3)/d (140 mgd), in different parts of the world (USA and Finland). The plants have different treatment objectives ranging from nitrification and partial denitrification (nitrate plus nitrite <8.7 mg/L) to enhanced nutrient removal (total nitrogen <3 mg/L, total phosphorus <0.3 mg/L). Commonly-used models were applied in the case studies, including ASM3 (using the GPS-X simulator), New General (using GPS-X), Dold (using BioWin), and a variation of the Dold model methanol degradation capabilities (NGmeth within GPS-X). The authors compare and contrast the modelling approaches taken, including calibration and validation approaches, sensitivity analyses, and the application of results to full-scale studies, designs and operations. Despite several differences between the approaches, there are many similarities which are discussed in light of the IWA draft uniform protocol for activated sludge modelling. The authors also discuss current modelling limitations and offer suggestions to improve the state of the art.

A balancing act: the consulting engineers' pragmatic view of process modelling

Modelling: what do we know, what do we want to know and why? The practical application of models to real projects is often circular because these questions weren't asked prior to making the decision to model the plant under study. Modelling wastewater treatment plants can provide insight into the inner workings of the process that might not be attainable any other way, but is that added process knowledge always needed or necessary and what criteria does one use to determine the level of effort required? These complex modelling decisions require education, communication, and improved understanding amongst both modellers and clients. This submission explores the use of models by consultants for consulting purposes and the balancing acts (time versus knowledge and cost versus benefit) that the consulting engineer must manage when embarking on any modelling project.

Sensitivity and specificity of Anti-HBc screening assays--which assay is best for blood donor screening?

Compared to HIV and hepatitis C virus, the residual infectious risk of hepatitis B virus (HBV) posed by blood products is about 10 times higher. In addition to HBsAg testing, screening for anti-HBc was recommended by the German Advisory Committee Blood in March 2005. Prevalence of anti-HBc in German blood donors was investigated at five test sites located in different geographic regions. In total, 12,000 blood donors were screened for anti-HBc by PRISM HBcore, and a statistically representative number of these were tested with Abbott Murex anti-HBc total, bioMérieux Hepanostika anti-HBc uniform, Bio-Rad Monolisa anti-HBc PLUS and Dade Behring Enzygnost anti-HBc. Anti-HBc repeat reactive samples were tested for anti-HBs, anti-HBe and HBV DNA by individual donation NAT. The mean prevalence of anti-HBc was 1.75% in donors that had not been tested for anti-HBc in the past. The percentage of anti-HBs in anti-HBc repeat reactive donors was 93.7%. Samples that were additionally reactive for anti-HBe were anti-HBc reactive in all tested assays. The sample to cut-off (S/Co) values for anti-HBc were lower (competitive assays) in samples that were also positive for anti-HBe, when compared to samples that were only anti-HBc reactive. Most commercially available anti-HBc assays provide sufficient sensitivity for routine screening purposes, and lacking specificity is no longer a serious issue for most of them. Assay differences were recognized for samples that were anti-HBc only reactive. The overall loss of 1.75% of positive testing donors can be significantly reduced to 0.45% by implementation of re-entry procedures for donors with an anti-HBs titre of over 100 IU/l and negative by sensitive ID-NAT.

Learning from local knowledge: modeling the pastoral-nomadic range management of the Himba, Namibia

It is widely accepted that successful grazing management strategies in semiarid ecosystems need to be adapted to the highly temporal and spatially heterogeneous forage production. Nevertheless, a full understanding of the key factors and processes for sustainable adaptive management has yet to be reached. The investigation of existing, successful range management systems by simulation models may help to derive general understanding and basic principles. The semi-nomadic Himba in northern Namibia applied a sophisticated management system until the mid-1990s which combined season-dependent pasture use (resulting in rainy-season pastures and dry-season pastures), preservation of reserves for drought and sanctions for rule breaking. A stochastic ecological simulation model has been developed here which represents the main aspects of this management system. With this model we analyze (1) which components of the traditional Himba strategy are essential for sustainability and (2) what happens to the state of the rangeland system under socioeconomic changes. This study shows that temporally and spatially heterogeneous pasture use yields higher productivity and quality of a pasture area than the pressure of homogeneous permanent grazing. Two aspects are of importance: (1) intra-annual heterogeneous use (resting of the dry-season pastures during the rainy season) and (2) interannual heterogeneous use (spatial extension of grazing in years of drought). This management system leads to an effective build-up and use of a buffer in the system: the reserve biomass (the non-photosynthetic reserve organs of the plants), an indicator for grazing and management history. Analyzing purchase as one form of socioeconomic change, we demonstrate that easier market access to purchase livestock may lead to a decline in vegetation quality. However, cattle production increases as long as rest periods on parts of the pasture during the rainy season are granted. Methodologically, we emphasize that simulation models offer an excellent framework for analyzing and depicting basic principles in sustainable range management derived from local knowledge. They provide the opportunity of testing whether these basic principles are also valid under different ecological and socioeconomic settings.

Integrating individual movement behaviour into dispersal functions

Dispersal functions are an important tool for integrating dispersal into complex models of population and metapopulation dynamics. Most approaches in the literature are very simple, with the dispersal functions containing only one or two parameters which summarise all the effects of movement behaviour as for example different movement patterns or different perceptual abilities. The summarising nature of these parameters makes assessing the effect of one particular behavioural aspect difficult. We present a way of integrating movement behavioural parameters into a particular dispersal function in a simple way. Using a spatial individual-based simulation model for simulating different movement behaviours, we derive fitting functions for the functional relationship between the parameters of the dispersal function and several details of movement behaviour. This is done for three different movement patterns (loops, Archimedean spirals, random walk). Additionally, we provide measures which characterise the shape of the dispersal function and are interpretable in terms of landscape connectivity. This allows an ecological interpretation of the relationships found.

A new method for conservation planning for the persistence of multiple species

Although the aim of conservation planning is the persistence of biodiversity, current methods trade-off ecological realism at a species level in favour of including multiple species and landscape features. For conservation planning to be relevant, the impact of landscape configuration on population processes and the viability of species needs to be considered. We present a novel method for selecting reserve systems that maximize persistence across multiple species, subject to a conservation budget. We use a spatially explicit metapopulation model to estimate extinction risk, a function of the ecology of the species and the amount, quality and configuration of habitat. We compare our new method with more traditional, area-based reserve selection methods, using a ten-species case study, and find that the expected loss of species is reduced 20-fold. Unlike previous methods, we avoid designating arbitrary weightings between reserve size and configuration; rather, our method is based on population processes and is grounded in ecological theory.

[Epidemiological, therapeutic and prognostic aspects of breast cancer: about 473 cases collected in Hopital Principal de Dakar]

INTRODUCTION

The aims of this study were to appreciate the epidemiological, therapeutic and pronostic aspects of breast cancer. This retrospective study was carried out in gynecology service in Hopital Principal of Dakar. We collected 473 cases of breast cancer over a period of 15 years, from January 1986 to December 2001.

MATERIALS AND METHODS

Only the patients having a histological diagnosis were involued. The identification of patients, their medical history, their present complaints and the different treatment performed, were registred. The actuarial method of survival was used.

RESULTS

The mean age of patients was 42.5 years; the average of parity was 4.7. The patients live in Dakar in 245 cases (51.7%). We had observed 279 cases (59.1%) diagnosed between six months and twelve months. Only 74 cases (15.8%) were diagnosed less than three months. In 282 cases (60%) the disease stage was T4N1Mx in TNM classification. In 425 cases (89.89) the histological type was infiltrate canal carcinoma. The surgery had concerned 441 patients (93.2%). And 52 of them (11%) underwent conservative treatment and 309 out of them (65.2%) underwent total mastectomy associated to axillary cleaning out like Patey method. Chemotherapy had been done in 426 cases (90%), hormonotherapy in 92 cases (19.4%) radiotherapy in 83 cases (17. 5%) and surgical costiation had been performed in 42 cases (8.8%). The overall survival at 15 years was (8.5%).

CONCLUSION

According to the issues of other african series we found out that our patients were young at the time of the diagnosis, We think that early diagnosis and appropriated treatment must improve the prognosis of breast cancer. The mass screening politics must be involved.

Metapopulation Persistence in Heterogeneous Landscapes: Lessons about the Effect of Stochasticity

This article addresses an important aspect of the analysis of metapopulation persistence. It highlights some consequences of ignoring and including stochasticity in the sequence of extinction and colonization events. The results are based on a comparative analysis of the outcomes of two (one deterministic, one stochastic) spatially realistic metapopulation models and a search for common effects and differences. One key result of the article is that, under certain conditions, there are extra effects of the landscape structure (number and configuration of patches, patch size distribution) on metapopulation persistence if stochasticity is included. In these cases, ignoring or including stochasticity can change conclusions about the persistence status but also ranking orders, relative results, and qualitative trends. A list of conditions is provided under which including stochasticity is vital to prevent counterproductive conclusions about metapopulation persistence. The results of the overall study are condensed in five lessons about the effect of stochasticity. A number of implications for ecological theory and conservation management are discussed. The study demonstrates the potential of three recently published approximation formulas (metapopulation capacity lambdaM, mean lifetime Tm, and effective number of patches N) to serve as tools for ecological analysis and thinking.

Foray search: an effective systematic dispersal strategy in fragmented landscapes

In the absence of evidence to the contrary, population models generally assume that the dispersal trajectories of animals are random, but systematic dispersal could be more efficient at detecting new habitat and may therefore constitute a more realistic assumption. Here, we investigate, by means of simulations, the properties of a potentially widespread systematic dispersal strategy termed "foray search." Foray search was more efficient in detecting suitable habitat than was random dispersal in most landscapes and was less subject to energetic constraints. However, it also resulted in considerably shorter net dispersed distances and higher mortality per net dispersed distance than did random dispersal, and it would therefore be likely to lead to lower dispersal rates toward the margins of population networks. Consequently, the use of foray search by dispersers could crucially affect the extinction-colonization balance of metapopulations and the evolution of dispersal rates. We conclude that population models need to take the dispersal trajectories of individuals into account in order to make reliable predictions.

Extracellular cysteines define ectopeptidase (APN, CD13) expression and function

Alanyl aminopeptidase (APN) is a surface-bound metallopeptidase that processes the N-terminals of biologically active peptides such as enkephalins, angiotensins, neurokinins, and cytokines. It exerts profound activity on vital processes such as immune response, cellular growth, and blood pressure control. Inhibition of either APN gene expression or its enzymatic activity severely affects leukocyte growth and function. We show here that oxidoreductase-mediated modulations of the cell surface thiol status affect the enzymatic activity of APN. Additional evidence for the pivotal role of extracellular cysteines in the APN molecule was obtained when substitution of any of these six cysteines caused complete loss of surface expression and enzymatic activity. In contrast, the transmembrane Cys24 appears to have no similar function. Enzymatically inactive cysteine mutants were retained in the endoplasmic reticulum as shown by high-resolution imaging and Endoglycosidase H digestion. In the absence of any crystal-structure data, the demonstration that individual extracellular cysteines contribute to APN expression and function appears to be of particular importance. The data are the first to show thiol-dependent modulation of the activity of a typical surface-bound peptidase at the cell surface, probably reflecting a general regulating mechanism. This may relate to various disease processes such as inflammation or malignant transformation.