Great saphenous vein diameter does not correlate with worsening quality of life scores in patients with great saphenous vein incompetence

ObjectivePrevious studies have correlated increasing great saphenous vein (GSV) diameter with increasing CEAP clinical classification. Some insurance carriers are currently using specific GSV diameters to determine coverage for treatment of axial venous insufficiency. The aim of this study was to investigate the correlation of patient quality of life (QOL) measures with GSV diameters in varicose vein patients with GSV reflux.MethodsData were collected from the records of 91 patients prospectively enrolled in two varicose vein trials. The patients had symptomatic varicose veins with saphenofemoral junction and proximal GSV reflux. Maximum GSV diameter was measured on duplex ultrasound imaging, with the patient standing, within 5 cm of the saphenofemoral junction. Chronic Venous Insufficiency Questionnaire 2 (CIVIQ-2; Servier, Neuilly-sur-Seine, France), Venous Insufficiency Epidemiological and Economic Study (VEINES) Symptom (Sym) and QOL assessments, and the Venous Clinical Severity Score (VCSS) assessment were completed before treatment of GSV insufficiency. Demographic information, patient weight, height, and body mass index were collected. Correlations between pairs of data were done using Pearson product-moment and Spearman correlation coefficients.ResultsThe 91 study patients (19 men, 72 women) were a mean age of 45 years (range, 18-65 years). The mean GSV diameter was 6.7 mm (range, 2.2-14.1 mm). The mean VCSS score was 7.8 (range, 3-12). There was a weak correlation between increasing GSV diameter and VCSS (r = 0.23; P = .03) and no correlation between GSV diameter and the CIVIQ-2 score (r = 0.01), VEINES-QOL (r = −0.07), and VEINES-Sym (r = −0.1).ConclusionsGSV diameter is a poor surrogate marker for assessing the effect of varicose veins on a patient's QOL; thus, using GSV diameter as a sole criterion for determining medical necessity for the treatment of GSV reflux is inappropriate. Further correlations between QOL measures and duplex-derived objective findings are warranted

Tools for multiaxial validation of behavior laws chosen for modeling hyper-elasticity of rubber-like materials

We present an experimental approach to discriminate hyper-elastic models describing the mechanical behavior of rubber-like materials. An evaluation of the displacement field obtained by digital image correlation allows us to evaluate the heterogeneous strain field observed during these tests. We focus on the particular case of hyper-elastic models to simulate the behavior of some rubber-like materials. Assuming incompressibility of the material, the hyper-elastic potential is determined from tension and compression tests. A biaxial loading condition is obtained in a multiaxial testing machine and model predictions are compared with experimental results

Encapsulation of FITC to monitor extracellular pH: a step towards the development of red blood cells as circulating blood analyte biosensors

A need exists for a long-term, minimally-invasive system to monitor blood analytes. For certain analytes, such as glucose in the case of diabetics, a continuous system would help reduce complications. Current methods suffer significant drawbacks, such as low patient compliance for the finger stick test or short lifetime (i.e., 3–7 days) and required calibrations for continuous glucose monitors. Red blood cells (RBCs) are potential biocompatible carriers of sensing assays for long-term monitoring. We demonstrate that RBCs can be loaded with an analyte-sensitive fluorescent dye. In the current study, FITC, a pH-sensitive fluorescent dye, is encapsulated within resealed red cell ghosts. Intracellular FITC reports on extracellular pH: fluorescence intensity increases as extracellular pH increases because the RBC rapidly equilibrates to the pH of the external environment through the chloride-bicarbonate exchanger. The resealed ghost sensors exhibit an excellent ability to reversibly track pH over the physiological pH range with a resolution down to 0.014 pH unit. Dye loading efficiency varies from 30% to 80%. Although complete loading is ideal, it is not necessary, as the fluorescence signal is an integration of all resealed ghosts within the excitation volume. The resealed ghosts could serve as a long-term (>1 to 2 months), continuous, circulating biosensor for the management of diseases, such as diabetes

An Effective Field Theory Calculation of the Parity Violating Asymmetry in n+p -> d+gamma

Weak interactions are expected to induce a parity violating pion-nucleon coupling, h_{\pi NN}^{(1)}. This coupling should be measurable in a proposed experiment to study the parity violating asymmetry A_\gamma in the process \vec n + p \to d+\gamma. We compute the leading dependence of A_\gamma on the coupling h_{\pi NN}^{(1)} using recently developed effective field theory techniques and find an asymmetry of A_\gamma = +0.17 h_{\pi NN}^{(1)} at leading order. This asymmetry has the opposite sign to that given by Desplanques, Donoghue and Holstein.Comment: 7 pages, 2 figures from 3 eps files, late

T-Duality in Arbitrary String Backgrounds

T-Duality is a poorly understood symmetry of the space-time fields of string theory that interchanges long and short distances. It is best understood in the context of toroidal compactification where, loosely speaking, radii of the torus are inverted. Even in this case, however, conventional techniques permit an understanding of the transformations only in the case where the metric on the torus is endowed with Abelian Killing symmetries. Attempting to apply these techniques to a general metric appears to yield a non-local world-sheet theory that would defy interpretation in terms of space-time fields. However, there is now available a simple but powerful general approach to understanding the symmetry transformations of string theory, which are generated by certain similarity transformations of the stress-tensors of the associated conformal field theories. We apply this method to the particular case of T-Duality and i) rederive the known transformations, ii) prove that the problem of non-locality is illusory, iii) give an explicit example of the transformation of a metric that lacks Killing symmetries and iv) derive a simple transformation rule for arbitrary string fields on tori.Comment: 25 pages, plain Tex, new references adde

Microwave-assisted synthesis of layered basic zinc acetate nanosheets and their thermal decomposition into nanocrystalline ZnO

We have developed a low-cost technique using a conventional microwave oven to grow layered basic zinc acetate (LBZA) nanosheets (NSs) from a zinc acetate, zinc nitrate and HMTA solution in only 2 min. The as-grown crystals and their pyrolytic decomposition into ZnO nanocrystalline NSs are characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), X-ray diffraction (XRD) and photoluminescence (PL). SEM and AFM measurements show that the LBZA NSs have typical lateral dimensions of 1 to 5 μm and thickness of 20 to 100 nm. Annealing in air from 200°C to 1,000°C results in the formation of ZnO nanocrystalline NSs, with a nanocrystallite size ranging from 16 nm at 200°C to 104 nm at 1,000°C, as determined by SEM. SEM shows evidence of sintering at 600°C. PL shows that the shape of the visible band is greatly affected by the annealing temperature and that the exciton band to defect band intensity ratio is maximum at 400°C and decreases by a factor of 15 after annealing at 600°C. The shape and thickness of the ZnO nanocrystalline NSs are the same as LBZA NSs. This structure provides a high surface-to-volume ratio of interconnected nanoparticles that is favorable for applications requiring high specific area and low resistivity such as gas sensing and dye-sensitized solar cells (DSCs). We show that resistive gas sensors fabricated with the ZnO NSs showed a response of 1.12 and 1.65 to 12.5 ppm and 200 ppm of CO at 350°C in dry air, respectively, and that DSCs also fabricated from the material had an overall efficiency of 1.3%

Acute intermittent porphyria presenting as progressive muscular atrophy in a young black man

Acute intermittent porphyria, the most common porphyria affecting the nervous system, typically presents with neurovisceral crises followed by a motor neuropathy. We describe a 23-year-old black South African man presenting with a progressive stuttering, lower motor neuron syndrome developing over months. He had not experienced pain or neuropsychiatric symptoms. One year after symptom onset he was bed-bound with a flaccid quadriparesis. There was marked amyotrophy, but without fasciculations. Sensation was intact apart from a hypo-aesthetic patch over the thigh. Electrophysiological investigations showed an active motor axonopathy. Urinary porphyrins, δ-aminolaevulinic acid and porphobilinogen were elevated. Mutation analysis revealed the c445C>T (R149X) mutation in the porphobilinogen deaminase gene. The patient responded dramatically to haem arginate and could walk with assistance 2 weeks later. We identified the first molecularly confirmed acute intermittent porphyria in a black South African. The clinical presentation mimicked a progressive lower motor neuron syndrome.

Gel-like inclusions of C-terminal fragments of TDP-43 sequester stalled proteasomes in neurons

International audienceAggregation of the multifunctional RNA-binding protein TDP-43 defines large subgroups of amyotrophic lateral sclerosis and frontotemporal dementia and correlates with neurodegeneration in both diseases. In disease, characteristic C-terminal fragments of ~25 kDa ("TDP-25") accumulate in cytoplasmic inclusions. Here, we analyze gain-of-function mechanisms of TDP-25 combining cryo-electron tomography, proteomics, and functional assays. In neurons, cytoplasmic TDP-25 inclusions are amorphous, and photobleaching experiments reveal gel-like biophysical properties that are less dynamic than nuclear TDP-43. Compared with full-length TDP-43, the TDP-25 interactome is depleted of low-complexity domain proteins. TDP-25 inclusions are enriched in 26S proteasomes adopting exclusively substrate-processing conformations, suggesting that inclusions sequester proteasomes, which are largely stalled and no longer undergo the cyclic conformational changes required for proteolytic activity. Reporter assays confirm that TDP-25 impairs proteostasis, and this inhibitory function is enhanced by ALScausing TDP-43 mutations. These findings support a pathophysiological relevance of proteasome dysfunction in ALS/FTD