134 research outputs found

    Coating Membranes for a Sorbent-Based Artificial Liver: Adsorption Characteristics

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    Techniques are described for the coating of sorbents to be used in an artificial liver support system based on mixed sorbent bed hemoperfusion. Activated charcoal has been coated with cellulose acetate (CA) by solvent evaporation. With Amberlite XAD-4, the Wurster technique was used for coating with CA. XAD-4 has also been coated with a synthetic polyelectrolyte with anticoagulant activity by adsorption and fixation by gamma radiation-induced crosslinking. Activated charcoal, XAD-4, and a cation exchange resin, all in powdered form, were encapsulated in agarose gel beads. Adsorption characteristics onto the sorbents are described. The results are in agreement with a theoretical model presented. In general, adsorption onto XAD-4 is limited by film diffusion. With activated charcoal, pore diffusion limitation is generally observed. Blood compatibility is improved by coatin

    A Practical Attack on the MIFARE Classic

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    The MIFARE Classic is the most widely used contactless smart card in the market. Its design and implementation details are kept secret by its manufacturer. This paper studies the architecture of the card and the communication protocol between card and reader. Then it gives a practical, low-cost, attack that recovers secret information from the memory of the card. Due to a weakness in the pseudo-random generator, we are able to recover the keystream generated by the CRYPTO1 stream cipher. We exploit the malleability of the stream cipher to read all memory blocks of the first sector of the card. Moreover, we are able to read any sector of the memory of the card, provided that we know one memory block within this sector. Finally, and perhaps more damaging, the same holds for modifying memory blocks

    Problems in Treating Experimentally Induced Acute Hepatic Failure by Hemoperfusion or Cross Circulation

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    Acute hepatic failure was induced in rats by galactosamine injection intraperitoneally (1 gm per kg). Twenty-four hours later rats were treated by hemoperfusion (HP) over encapsulated sorbents: cellulose acetate-coated charcoal, polyelectrolyte-coated XAD4, a combination of both, or cross circulation with a healthy donor. Compared with control treatment (prevention of hypoglycemia by glucose infusion), the survival rate was not improved by HP or cross circulation: controls 19% vs. treated animals 0 to 17%. Extension of duration or increased frequency of HP gave the same survival rates. Computer simulation based on zero-order introduction of a possible toxin into a two-compartment model shows that HP up to 5 hr per day is not able to clear the body effectively from the assumed toxin if its partition coefficient exceeds a value of 50

    Impact of digital interdisciplinary consultation on secondary care referrals by general practitioners:a protocol for a stepped-wedge cluster randomised controlled trial

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    INTRODUCTION: Optimal collaboration between general practice and hospital care is crucial to maintain affordable and sustainable access to healthcare for the entire population. General practitioners (GPs) are the gatekeepers to specialist care and patients will visit hospitals mostly only after referral. However, a substantial part of these referrals may be inappropriate, as communication between GPs and medical specialists can be challenging and referring patients may be the most obvious action for a GP to perform.A new digital platform (Prisma) connects GPs and specialists in interdisciplinary groups and facilitates asynchronous, accessible and fast teleconsultation within the group. No previous research has been done to evaluate the impact of this new platform on the referral rates to the hospital. METHODS AND ANALYSIS: A stepped-wedge randomised controlled trial (RCT) will be performed in Zwolle region in the Netherlands to analyse the effect of introduction of the platform on rate of inappropriate referrals to orthopaedic surgery. In four steps, GPs in the region will be given access to the platform. GPs will be part of the control condition until randomisation to the intervention. According to our sample size calculation, we need to include 18 practices with 1008 patients presenting with hip and knee symptoms. Routine care data of hospital registrations will be analysed to calculate the rate of inappropriate referrals (primary outcome). Secondary outcome are costs, primary and secondary care workload, posted cases and user satisfaction. Alongside this quantitative analysis, we will evaluate patient experience, facilitators and barriers for use of the platform. ETHICS AND DISSEMINATION: The medical ethics review board of University Medical Center Groningen (UMCG), the Netherlands (METc-number: 2021/288) has confirmed that the Medical Research Involving Human Subjects Act (WMO) does not apply to the process evaluation because the study does not involve randomisation of patients or different medical treatments (letter number: M21.275351). TRIAL REGISTRATION NUMBER: NL9704

    Genetic parameters of colostrum and calf serum antibodies in Swedish dairy cattle

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    BackgroundA sufficient IgG content in the colostrum is essential for the newborn calf, as it provides passive immunity which substantially affects the probability of survival during rearing. Failure of passive transfer (FPT) occurs when a calf does not absorb enough antibodies from the colostrum and is defined by an IgG concentration in calf serum lower than 10 g/L. Apart from delayed access to colostrum, FPT can be due to a low production of IgG in the mother or poor IgG absorption by the calf. The aim of this study was to estimate the genetic background of antibody levels and indicator traits for antibodies in the colostrum and calf serum, and their correlation with milk production.ResultsColostrum data were available for 1340 dairy cows with at least one calving and calf serum data were available for 886 calves from these cows. Indicator traits for antibody concentrations were estimated using refractometry (a digital Brix refractometer for colostrum and an optical refractometer for serum), and enzyme-linked immunosorbent assays (ELISA) were used to determine the levels of total IgG and natural antibodies (NAb) of various antibody isotypes in the colostrum and calf serum. Colostrum traits had heritabilities ranging from 0.16 to 0.31 with repeatabilities ranging from 0.21 to 0.55. Brix percentages had positive genetic correlations with all colostrum antibody traits including total IgG (0.68). Calf serum antibody concentrations had heritabilities ranging from 0.25 to 0.59, with a significant maternal effect accounting for 17 to 27% of the variance. When later in life calves produced their first lactation, the lactation average somatic cell score was found to be negatively correlated with NAb levels in calf serum.Conclusions​​​​​​​Our results suggest that antibody levels in the colostrum and calf serum can be increased by means of selection

    Psychological factors associated with changes in physical activity in Dutch people with type 2 diabetes under societal lockdown:A cross-sectional study

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    AIMS: To investigate changes in physical activity (PA) and psychological factors during societal lockdown in people with type 2 diabetes. METHODS: A cross‐sectional study among Dutch adults with type 2 diabetes. Data were collected using online questionnaires. A multivariate multinomial logistic regression was performed with change in PA during societal lockdown as outcome and perceived change in stress, anxiety, perceived risk for COVID‐19 infection, emotional well‐being and former PA status as determinants. RESULTS: Five hundred and sixty seven respondents filled out the questionnaire, 536 were included in the final analysis: mean age of 65.9 ± 7.9 years; mean diabetes duration 13.3 ± 8 years; 54% men; 47% reported no change in PA, 27% became less active and 26% became more active during societal lockdown. Participants who were more likely to become less active were participants who experienced more stress (OR: 2.27; 95% CI 1.25–4.13) or less stress (OR: 2.20; 95% CI 1.03–4.71). Participants who were more likely to become more active were participants who experienced more stress (OR: 2.31; 95% CI 1.25, 4.26). Participants with higher emotional well‐being (OR: 0.98; 95% CI 0.97, 0.99) were less likely to become less active than to report no change in PA. CONCLUSIONS: Changes in PA in people with type 2 diabetes during societal lockdown are associated with changes in psychological factors such as perceived stress and emotional well‐being. People with diabetes and their caregivers should be aware of these possible changes

    Bracing patients with idiopathic scoliosis: Design of the Dutch randomized controlled treatment trial

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    Background. The effectiveness of bracing patients with IS has not yet been convincingly established due to a lack of RCTs. Some authors suggest that their results confirm that bracing is effective; others conclude that the effectiveness of bracing is doubtful or recommend a RCT. The aim of this study was to establish whether bracing patients with idiopathic scoliosis (IS) in an early stage will result in at least 5 degrees less mean progression of the curvature compared to the control group after two years of follow-up. Methods. A randomized controlled trial was designed. Eligible patients are girls and boys in the age group 8-15 years whose diagnosis of IS has been established by an orthopedic surgeon, who have not yet been treated by bracing or surgery, and for whom further growth of physical height is still expected based on medical examination and maturation characteristics (Risser ? 2). The Cobb angle of the eligible patient should either be minimally 22 and maximally 29 degrees with established progression of more than 5 degrees, or should be minimally 30 and maximally 35 degrees; established progression for the latter is not necessary. A total of 100 patients will be included in this trial. The intervention group will be treated with full-time Boston brace wear; the control group will not be braced. Every four months, each patient will have a physical and an X-ray examination. The main outcomes will be the Cobb angle two years after inclusion and health-related quality of life. Discussion. The results of this trial will be of great importance for the discussion on early treatment for scoliosis. Furthermore, the result will also be important for screening for scoliosis policies. Trial registration. Nederlands Trialregister ISRCTN36964733

    Peptides from the variable region of specific antibodies are shared among lung cancer patients

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    Late diagnosis of lung cancer is still the main reason for high mortality rates in lung cancer. Lung cancer is a heterogeneous disease which induces an immune response to different tumor antigens. Several methods for searching autoantibodies have been described that are based on known purified antigen panels. The aim of our study is to find evidence that parts of the antigen-binding-domain of antibodies are shared among lung cancer patients. This was investigated by a novel approach based on sequencing antigen-binding- fragments (Fab) of immunoglobulins using proteomic techniques without the need of previously known antigen panels. From serum of 93 participants of the NELSON trial IgG was isolated and subsequently digested into Fab and Fc. Fab was purified from the digested mixture by SDS-PAGE. The Fab containing gel-bands were excised, tryptic digested and measured on a nano-LC-Orbitrap-Mass- spectrometry system. Multivariate analysis of the mass spectrometry data by linear canonical discriminant analysis combined with stepwise logistic regression resulted in a 12-antibody-peptide model which was able to distinguish lung cancer patients from controls in a high risk population with a sensitivity of 84% and specificity of 90%. With our Fab-purification combined Orbitrap-mass-spectrometry approach, we found peptides from the variable-parts of antibodies which are shared among lung cancer patients

    PHP48 COST SENSITIVENESS AND PHYSICIAN TREATMENT CHOICES

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    Objectives To explore the relationship between nodule count and lung cancer probability in baseline low-dose CT lung cancer screening. Materials and Methods Included were participants from the NELSON trial with at least one baseline nodule (3392 participants [45% of screen-group], 7258 nodules). We determined nodule count per participant. Malignancy was confirmed by histology. Nodules not diagnosed as screen-detected or interval cancer until the end of the fourth screening round were regarded as benign. We compared lung cancer probability per nodule count category. Results 1746 (51.5%) participants had one nodule, 800 (23.6%) had two nodules, 354 (10.4%) had three nodules, 191 (5.6%) had four nodules, and 301 (8.9%) had > 4 nodules. Lung cancer in a baseline nodule was diagnosed in 134 participants (139 cancers; 4.0%). Median nodule count in participants with only benign nodules was 1 (Inter-quartile range [IQR]: 1–2), and 2 (IQR 1–3) in participants with lung cancer (p = NS). At baseline, malignancy was detected mostly in the largest nodule (64/66 cancers). Lung cancer probability was 62/1746 (3.6%) in case a participant had one nodule, 33/800 (4.1%) for two nodules, 17/354 (4.8%) for three nodules, 12/191 (6.3%) for four nodules and 10/301 (3.3%) for > 4 nodules (p = NS). Conclusion In baseline lung cancer CT screening, half of participants with lung nodules have more than one nodule. Lung cancer probability does not significantly change with the number of nodules. Baseline nodule count will not help to differentiate between benign and malignant nodules. Each nodule found in lung cancer screening should be assessed separately independent of the presence of other nodules
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