Vascular access thrombosis in France: incidence and treatment patterns.

BACKGROUND: Vascular access thrombosis lacks the implementation of a treatment algorithm at large scale, involving all the actors. We aimed to determine a better understanding of the current practice patterns around vascular access thrombosis in France, with 4 axes: incidence, surveillance protocol, treatment, and time to treatment. METHODS: A comprehensive survey of all the nephrologists staffing all hemodialysis centers in France during April 2013 included 266 of 269 (99%) centers, treating 27,798 patients with arteriovenous fistula or graft. RESULTS: In 104 centers treating 11,088 patients, there were 905 documented episodes of vascular access thrombosis (8.8%) in 1 year; in the other 162 centers that supplied a range of events, the mean incidence was 8.4%. Use of in-line access flow monitoring as part of surveillance program was not correlated with better outcome compared with Doppler ultrasound (thrombosis: 7.9% vs. 10%, respectively, P = 0.09). Fifty-three percent of centers referred the patients to a vascular surgeon and 32% to an interventional radiologist (2% to urologist and 13% variable referral depending on the case complexity). Time to treatment was <24 hr in 58% and <48 hr in 91% of the centers; treatment >48 hr (9%) occurred mainly in rural zones (P = 0.04). The specialty of the treating physician did not influence time to treatment (P > 0.05). CONCLUSIONS: In France, vascular access thrombosis rate is low and not influenced by surveillance protocol type. Most patients can receive timely treatment by vascular surgeons or interventional radiologists.

Linear attenuation coefficient and buildup factor of MCP-96 alloy for dose accuracy, beam collimation, and radiation protection.

The linear attenuation coefficients and buildup factor of MCP-96 alloy were determined for (60)Co, (54)Mn, and (137)Cs gamma emitters and a NaI detector. The thickness of the MCP-96 attenuator was varied from 1 to 4 cm. A collimated beam of gamma rays was allowed to pass through various thicknesses of the MCP-96 alloy. The attenuated beam was detected by a NaI detector, and data were recorded by a multichannel analyzer. The run was repeated without the collimator for broad-beam geometry. For each run, the attenuated beam intensity was normalized by the intensity of the unattenuated incident beam obtained by removing the attenuators. Linear attenuation coefficients were determined by plotting of the intensity of the collimated beam against the attenuator thickness. For every thickness of the alloy, the ratio of the attenuated to the unattenuated beam was found to be higher in broad-beam geometry as compared to the same ratio in narrow-beam geometry. We used the difference in these ratios in broad and narrow-beam geometries to calculate the buildup factor. The buildup factor was found to increase with beam energy and attenuator thickness. Variation in the source-to-detector distance gave a lower value of the buildup factor for a small and a large distance and a higher value for an intermediate distance. The buildup factor was found to be greater than 1 in all cases. We conclude that the buildup factor must be calculated and incorporated for dose correction and precision when the MCP-96 alloy is used for tissue compensation or radiation shielding and protection purposes.

Do we know how to use corticosteroids in acute severe ulcerative colitis?

Options for the treatment of acute severe ulcerative colitis have broadened with the use of ciclosporin and infliximab, but corticosteroids remain first-line treatment. However, an optimum regimen for drug, dose and duration has not been established in the 57 years since Truelove and Witts first reported their value. In the absence of evidenced-based guidance this study sought to discover how gastroenterology units in the UK manage patients with acute severe colitis. In January 2010 a questionnaire was sent to all members of the inflammatory bowel disease section of the British Society of Gastroenterology enquiring about their use of corticosteroids in a typical patient with acute severe colitis. One hundred and two responses were obtained, representing more than 50% of the UK gastroenterology units. No consensus, and a wide variation in practice was found between these units. Over 70% of responders initially treat patients with intravenous hydrocortisone (400 mg/day), although some units prefer methylprednisolone and dexamethasone. On transfer to oral treatment, all units use prednisolone, most starting with 40 mg/day. There are no agreed national or international guidelines on the reducing regimen or duration of oral treatment-the area of greatest variation in our survey. Most units reduce prednisolone by 5 mg/week, but because of variations in the timing and magnitude of dose reduction, total exposure to prednisolone varies by 2.6-fold. To minimise harm from undertreatment or overtreatment of acute severe colitis a controlled study of prednisolone dose and duration is needed.

The phytopathogenic fungus Alternaria brassicicola: phytotoxin production and phytoalexin elicitation.

The metabolites and phytotoxins produced by the phytopathogenic fungus Alternaria brassicicola (Schwein.) Wiltshire, as well as the phytoalexins induced in host plants, were investigated. Brassicicolin A emerged as the most selective phytotoxic metabolite produced in liquid cultures of A. brassicicola and spirobrassinin as the major phytoalexin produced in infected leaves of Brassica juncea (whole plants). In detached infected leaves of B. juncea, the main component was N'-acetyl-3-indolylmethanamine, the product of detoxification of the phytoalexin brassinin by A. brassicicola. In addition, the structure elucidation of three hitherto unknown metabolites having a fusicoccane skeleton was carried out and the antifungal activity of several plant defenses against A. brassicicola was determined.

Radium-228 analysis of natural waters by Cherenkov counting of Actinium-228.

The activities of (228)Ra in natural waters were determined by the Cherenkov counting of the daughter nuclide (228)Ac. The radium was pre-concentrated on MnO(2) and the radium purified via ion exchange and, after a 2-day period of incubation to allow for secular equilibrium between the parent-daughter (228)Ra((228)Ac), the daughter nuclide (228)Ac was isolated by ion exchange according to the method of Nour et al. [2004. Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin. Appl. Radiat. Isot. 61, 1173-1178]. The Cherenkov photons produced by (228)Ac were counted directly without the addition of any scintillation reagents. The optimum Cherenkov counting window, sample volume, and vial type were determined experimentally to achieve optimum Cherenkov photon detection efficiency and lowest background count rates. An optimum detection efficiency of 10.9+/-0.1% was measured for (228)Ac by Cherenkov counting with a very low Cherenkov photon background of 0.317+/-0.013cpm. The addition of sodium salicylate into the sample counting vial at a concentration of 0.1g/mL yielded a more than 3-fold increase in the Cherenkov detection efficiency of (228)Ac to 38%. Tests of the Cherenkov counting technique were conducted with several water standards of known activity and the results obtained compared closely with a conventional liquid scintillation counting technique. The advantages and disadvantages of Cherenkov counting compared to liquid scintillation counting methods are discussed. Advantages include much lower Cherenkov background count rates and consequently lower minimal detectable activities for (228)Ra and no need for expensive environmentally unfriendly liquid scintillation cocktails. The disadvantages of the Cherenkov counting method include the need to measure (228)Ac Cherenkov photon detection efficiency and optimum Cherenkov counting volume, which are not at all required when liquid scintillation analysis is used.

Sickle cell hemoglobin C disease in Saudi Arabia.

Sickle cell hemoglobin C (HbSC) is a disease confined to people of West African ancestry and it has not been reported in the Kingdom of Saudi Arabia (KSA). We are reporting 2 patients with HbSC disease from the western province of KSA (Madinah); one patient presented with severe form of the disease which include transient hypertension.