Hemodialysis access-related survival and morbidity in an elderly population in South West Thames, UK

Elderly patients form the most rapidly expanding group of hemodialysis (HD) patients in Europe and the United States. There are initiatives to promote an increase in arteriovenous fistula (AVF) formation. There are concerns that elderly patients may have lower rates of surgical vascular access compared with younger patients due to risks of higher co-morbidities, surgical complications, and higher AVF nonuse rates. The aim of this study was to compare access-related survival and morbidity for dialysis catheters and AVFs and to evaluate the AVF nonuse rate in an elderly population. We have performed a retrospective analysis of access survival and morbidity in patients > or = 70 years of age, either on maintenance HD or predialysis with preemptive formation of surgical access. One hundred and forty-six patients had permanent HD access created during the 18-month study period, from 1 January 2006 to June 2007. There were 89 male and 57 female patients in whom 78 AVFs and 137 tunneled venous catheters were inserted. There was a significantly greater loss of vascular access due to infection in the catheter group compared with the AVF group (P<0.016). Access survival was also significantly prolonged in the AVF group (446 days, 95% confidence interval 405-487) compared with the catheter group (276 days, 95% confidence interval 240-313), P=0.001. The rate of nonuse of AVFs was low (16%). We conclude that an AVF is the preferred form of vascular access in elderly HD patients.     

How Do Xanthan and Hydroxypropyl Methylcellulose Individually Affect the Physicochemical Properties in a Model Gluten‐Free Dough?

To better understand the physicochemical changes imparted by hydrocolloids on gluten-free dough, 2 hydroxypropyl methylcelluloses (HPMCs) and xanthan gum were added at 2%, 3%, and 5% to rice cassava dough without the addition of alternative proteins. The formulated doughs were analyzed using thermoanalytic and rheological techniques to determine the role of water and subsequent flow behavior upon hydrocolloid addition. The baked loaves were then measured for specific loaf volume and tensile strength to determine bread quality. Thermogravimetric analysis (TGA) results revealed that hydrocolloid-added dough held water more tightly than the rice cassava control with an additional water distribution at 85 to 88 °C. Rheologically, the increase of elastic moduli in the low methoxy HPMC and xanthan-added dough became more pronounced with gum addition; however, both HPMC formulations had increased viscous moduli allowing the gas cells to expand without collapsing. In the bread, the final specific loaf volume increased with high methoxy HPMC (2% to 5%) and low methoxy HPMC (2%) but was depressed with increased addition of low methoxy HPMC (5%) and xanthan (3% and 5%). Crumb hardness was decreased in high methoxy HPMC loaves but was increased significantly in low methoxy HPMC (5%) and xanthan (5%) formulations. From the gums studied, it was concluded that high methoxy HPMC was the optimum hydrocolloid in the rice cassava gluten-free dough. PRACTICAL APPLICATION: Two types of hydrocolloids, xanthan gum and HPMC, were individually added to a gluten-free rice cassava formulation. Based on the thermoanalytic and rheological studies on dough, as well as the bread quality studies, high methoxy HPMC at 5% addition was determined to optimally improve the bread quality when only gum addition was considered. This study indicates the potential use of high methoxy HPMC as an additive in gluten-free bread formulations prior to considering alternative proteins.     

Synthesis of an ionic N-nitrosamine and a method for its determination in foodstuffs

Summary A model ionic N-nitrosamine (N-nitroso-N¹N¹-dimethylpiperazinium iodide) was synthesised in order to develop an appropriate analytical method for examining the possible incidence of this class of compounds in food. A procedure suitable for its analysis in biological samples is described and is based on preparation of an aqueous extract, ion-pair extraction into an organic solvent, separation by high-performance liquid chromatography and detection with a thermal-energy analyzer. The average recovery of the ionic N-nitrosamine from cured meat was 83% at 200 g/kg; the detection limit was 50 gm/kg. bei den Muskelproben nahezu 30% der mit Hilfe der

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Synthese eines Ionischen N-Nitrosamins und eine Methode für dessen Analyse in Lebensmitteln

Zusammenfassung Ein Modell eines ionischen N-Nitrosamins (N-Nitroso-N¹N¹-dimethylpiperaziniodid) wurde synthetisiert, um die entsprechende analytische Methode zur Prüfung des möglichen Auftretens von Verbindungen dieser Klasse in Lebensmitteln zu entwickeln. Es wird ein für die Analyse dieses Stoffes in biologischen Proben geeignetes Verfahren beschrieben, das auf der Zubereitung eines wäßrigen Extrakts, Ionenpaar-Extraktion in einem organischen Lösungsmittel, Trennung durch Hochleistungs-Flüssigkeitschromatographie und Nachweis mit Hilfe eines thermischen Energieanalysators beruht. Aus geräuchertem Fleisch mit einem Gehalt von 200 g ionischem N-Nitrosamin/kg wurden im Durchschnitt 83% des Stoffes extrahiert, die Methode hat eine Nachweisgrenze von 50 g/kg.

     

Does a two-year period of orthokeratology lead to changes in the endothelial morphology of children?

Purpose

To compare changes in endothelial morphology in the central and superior cornea in subjects wearing single-vision spectacles and orthokeratology lenses over two years.

Effects of soy protein isolate and egg white solids on the physicochemical properties of gluten-free bread

Gluten-free formulations are often supplemented with proteins to improve their quality. To determine the effects of alternative proteins on a hydroxypropyl methylcellulose (HPMC)-treated gluten-free dough system, soy protein isolate was added at 1%, 2% and 3% while egg white solids were investigated at 5%, 10% and 15%. The formulated doughs were analysed using thermoanalytic and rheological techniques to determine the role of water and subsequent flow behaviour upon hydrocolloid addition. The baked loaves were measured for specific loaf volume and tensile strength to determine bread quality. The addition of soy protein isolate and egg white solids (5% and 10%) reduced dough stability by suppressing HPMC functionality, reducing available water, weakening HPMC interactions with the starch matrix and reducing foam stability. At 15% addition, egg white solids became the primary protein scaffolding in the dough and overcame negative interactions with HPMC, improving the loaf volume. However, this formulation may need further optimisation to meet full consumer acceptability.     

Speciation analysis of arsenic in landfill leachate

As environmental impacts of landfill last from beginning of cell filling to many years after, there is an increasing interest in monitoring landfill leachate composition especially with regards to metals and metalloids. High-performance liquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) has been applied to the speciation of arsenic in landfill leachates. The difficulty is related to the complexity and heterogeneity of leachate matrices. A soft sample preparation protocol with water dilution and filtration of leachates has proved to be sufficient for the achievement of identification and quantification of arsenic species without matrix effect. The cationic-exchange separation method developed has enabled the detection of six arsenic species (AsIII, MMA, AsV, DMA, AsB, TMAO) in different landfill leachates. The wide range of concentrations of arsenic species (from 0.2 to 250 microg As L(-1)) and their repartition illustrate the high variability of these effluents depending on the nature of the wastes, the landfill management, the climatic conditions and the degradation phase, to list a few. These results provide new information about the chemical composition of these effluents which is useful to better adapt their treatment and to achieve the risk assessment of landfill management.     

Highly Tuneable Photochromic Sodalites for Dosimetry,Security Marking and Imaging

Photochromic sodalites are considered for a plethora of possible applications, such as UV indexing and X-ray imaging, but for many of these the materials are yet to be optimized. UV indexing can be improved through incremental adjustment of the activation energy of coloration from 300 to 410 nm through replacement of sulfur with selenium. By combining this and other methods of tuning presented in the literature, the excitation threshold and photochromism color can be tuned independently of one another. The range of possible absorption maxima is expanded to 420–680 nm, or almost the entire visible spectrum. Mixing low-cost and easy-to-synthesize sodalites further broadens the possible range of colors and facilitates development of a unique sodalite mix capable of quantifying the doses of two types of UV radiation simultaneously. Finally, the response to X-rays of these highly tuned sodalites is investigated, and it is found that they can be sensitized to produce clear, high-contrast X-ray images at significantly lower doses of radiation than those required by classic photochromic sodalite, Na₈(AlSiO₄)₆(Cl,S)₂.