Hypertrophic scars after therapy with CO2 laser for treatment of multiple cutaneous neurofibromas

BACKGROUND. CO2 laser surgery is a treatment modality for cutaneous neurofibromas. OBJECTIVE. Hypertrophic and atrophic scars can result from treatment with CO2 laser surgery. We present a case of cutaneous neurofibromatosis that developed hypertrophic scars postoperatively. METHODS. Continuous wave CO2 laser surgery therapy was applied to the patient. RESULTS. Hypertrophic scars developed 2 months after therapy. CONCLUSION. With a preliminary test treatment the patient is able to see the expected result

Von Neumann's expanding model on random graphs

Within the framework of Von Neumann's expanding model, we study the maximum growth rate r achievable by an autocatalytic reaction network in which reactions involve a finite (fixed or fluctuating) number D of reagents. r is calculated numerically using a variant of the Minover algorithm, and analytically via the cavity method for disordered systems. As the ratio between the number of reactions and that of reagents increases the system passes from a contracting (r1). These results extend the scenario derived in the fully connected model (D\to\infinity), with the important difference that, generically, larger growth rates are achievable in the expanding phase for finite D and in more diluted networks. Moreover, the range of attainable values of r shrinks as the connectivity increases.Comment: 20 page

Typical properties of optimal growth in the Von Neumann expanding model for large random economies

We calculate the optimal solutions of the fully heterogeneous Von Neumann expansion problem with $N$ processes and $P$ goods in the limit $N\to\infty$. This model provides an elementary description of the growth of a production economy in the long run. The system turns from a contracting to an expanding phase as $N$ increases beyond $P$. The solution is characterized by a universal behavior, independent of the parameters of the disorder statistics. Associating technological innovation to an increase of $N$, we find that while such an increase has a large positive impact on long term growth when $N\ll P$, its effect on technologically advanced economies ($N\gg P$) is very weak.Comment: 8 pages, 1 figur

A weighted belief-propagation algorithm to estimate volume-related properties of random polytopes

In this work we introduce a novel weighted message-passing algorithm based on the cavity method to estimate volume-related properties of random polytopes, properties which are relevant in various research fields ranging from metabolic networks, to neural networks, to compressed sensing. Unlike the usual approach consisting in approximating the real-valued cavity marginal distributions by a few parameters, we propose an algorithm to faithfully represent the entire marginal distribution. We explain various alternatives to implement the algorithm and benchmark the theoretical findings by showing concrete applications to random polytopes. The results obtained with our approach are found to be in very good agreement with the estimates produced by the Hit-and-Run algorithm, known to produce uniform sampling.Comment: 17 pages, 6 figure

Venae perforantes: A clinical review

BACKGROUND. Although many articles on perforating veins have been published, much knowledge about these veins is lacking. OBJECTIVE. In this review relevant facts about the clinical importance of perforating veins in venous disease are described. METHODS. A literature search on English, French and German articles has been performed using literature databases like Medline, Embase and Cochrane. RESULTS. Selection criteria are described. CONCLUSION. A few conclusions are drawn: incompetent perforating veins can be of haemodynamic importance, especially in venous ulceration and (recurrent) varicose veins. The current definition of incompetent perforating veins is reflux more than 0,5 seconds (detected by Duplex ultra-sonography). Good anatomical and clinical classifications are published and should be integrated in the CEAP classification. Based on the clinical classification treatment options are described for the different types of incompetent perforating veins. Two different treatment modalities for incompetent perforating veins are surgery (SEPS) and sclerotherapy. SEPS seems to be of benefit in patients with venous ulceration and advanced CVI. Sclerotherapy (especially ultra sound guided sclerotherapy) is promising and worth further evaluation

Duplication of the great saphenous vein: A definition problem and implications for therapy

BACKGROUND: In the literature there is a range from 1% to 20% of duplication (up to 20%) of the great saphenous vein (GSV) reported, because there is a lack of an accurate definition of the GSV and objective parameters for an anatomical identification. OBJECTIVE: To investigate the frequency of true duplications of the GSV. MATERIALS AND METHODS: A systematic review of the literature, a retrospective analysis of duplex examinations, and a prospective study of duplex examinations to investigate the frequency of true duplications of the GSV. RESULTS: In the literature review, a great variety of definitions is used for duplication of the GSV. Before the consensus of the Union International de Phlébologie (UIP) in 2006, Only in a small number of studies, the definition of the GSV in the saphenous compartment between the fascial blades is mentioned. CONCLUSION: Phlebographic studies have been the criterion standard for the identification of venous anatomy. Now, duplex is regarded as the criterion standard for accurate detection of the veins. True duplication of the GSV is less common than the previous literature has suggested, namely 1.6% to 2%. It is recommended that the duplicated GSV should be treated to avoid an important risk of recurrence of venous insufficiency

Does tumescent liposuction damage the lymph vessels in lipoedema patients?

Background: Lymphatic insufficiency might play a significant role in the pathophysiology of lipoedema. Liposuction is up to now the best treatment. As liposuction is invasive, the technique could destruct parts of the lymphatic system and by this aggravate the lymphatic component and/or induce lymphoedema. We investigated the function of the lymphatic system in lipoedema patients before and after tumescent liposuction and thus whether tumescent liposuction can be regarded as a safe treatment. Methods: Lymphoscintigraphy was performed to quantify the lymph outflow of 117 lipoedema patients. Mean clearance percentages of radioactive protein loaded after 1 min with respect to the total injected dose and corrected for decay of the radiopharmaceutical in the subcutaneous lymphatics were used as functional quantitative parameters as well as the clearance percentages and inguinal uptake 2 h post injection. The results of lymphatic function in lipoedema patients were compared with values obtained from normal healthy volunteers. We also compared 50 lymphoscintigraphies out of the previous 117 lipoedema patients before and six months after tumescent liposuction. Results: In 117 lipoedema patients clearance 2 h post injection in the right and left foot was disturbed in 79.5 and 87.2% respectively. The inguinal uptake 2 h post injection in the right and left groin was disturbed in 60.3 and 64.7% respectively. In 50 lipoedema patients mean clearance and inguinal uptake after tumescent liposuction were slightly improved, 0.01 (p = 0.37) versus 0.02 (p = 0.02), respectively. This is statistically not relevant in clearance. Conclusion: Lipoedema legs have a delayed lymph transport. Tumescent liposuction does not diminish the lymphatic function in lipoedema patients, thus tumescent liposuction can be regarded as a safe treatment.</p

Incidence, Prevalence and Future Trends of Primary Basal Cell Carcinoma in the Netherlands

Abstract: Basal cell carcinoma (BCC) incidence rates are increasing worldwide. This study’s objective was to estimate the occurrence of BCC in the Netherlands in terms of incidence and prevalence. Data on first primary carcinomas were retrieved from the Eindhoven Cancer Registry and extrapolated to the Dutch population. Extrapolated data showed a total of 444,131, histologically confirmed cases in the Netherlands between 1973 and 2008. During this period, age-adjusted incidence rates (European Standard Population) increased approximately three-fold from 40 to 148 per 100,000 in males and from 34 to 141 in females. Lifetime risk of BCC was 1 in 5–6 for Dutch citizens. Disease prevalence in the Netherlands was 1.4% and almost four times higher than this (5.4%) in the oldest age group (age 65 years or more). Predictions of future trends showed no signs of a plateau in the number of cases. These estimates should urge Dutch policymakers to provide solutions for the growing group of patients with BCC

Identifying essential genes in E. coli from a metabolic optimization principle

Understanding the organization of reaction fluxes in cellular metabolism from the stoichiometry and the topology of the underlying biochemical network is a central issue in systems biology. In this task, it is important to devise reasonable approximation schemes that rely on the stoichiometric data only, because full-scale kinetic approaches are computationally affordable only for small networks (e.g. red blood cells, about 50 reactions). Methods commonly employed are based on finding the stationary flux configurations that satisfy mass-balance conditions for metabolites, often coupling them to local optimization rules (e.g. maximization of biomass production) to reduce the size of the solution space to a single point. Such methods have been widely applied and have proven able to reproduce experimental findings for relatively simple organisms in specific conditions. Here we define and study a constraint-based model of cellular metabolism where neither mass balance nor flux stationarity are postulated, and where the relevant flux configurations optimize the global growth of the system. In the case of E. coli, steady flux states are recovered as solutions, though mass-balance conditions are violated for some metabolites, implying a non-zero net production of the latter. Such solutions furthermore turn out to provide the correct statistics of fluxes for the bacterium E. coli in different environments and compare well with the available experimental evidence on individual fluxes. Conserved metabolic pools play a key role in determining growth rate and flux variability. Finally, we are able to connect phenomenological gene essentiality with `frozen' fluxes (i.e. fluxes with smaller allowed variability) in E. coli metabolism.Comment: 9 pages, to appear in PNAS, see http://www.pnas.org/content/early/2009/02/05/0813229106.abstract for the early editio