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Kv1.2 potassium channels influence excitability and action potential propagation in the nervous system. Unlike closely-related Kv1 channels, Kv1.2 exhibits highly variable voltage-dependence of gating, attributed to regulation by unidentified extrinsic factors. Variability of Kv1.2 gating is strongly influenced by the extracellular redox potential, and we demonstrate that Kv1.2 currents in dorsal root ganglion sensory neurons exhibit similar variability and redox sensitivity as observed when the channel is heterologously expressed in cell lines. We used a functional screening approach to test the effects of candidate regulatory proteins on Kv1.2 gating, using patch clamp electrophysiology. Among 52 candidate genes tested, we observed that co-expression with the transmembrane lectin LMAN2 led to a pronounced gating shift of Kv1.2 activation to depolarized voltages in CHO and L(tk-) cell lines, accompanied by deceleration of activation kinetics. Overexpression of LMAN2 promoted a slow gating mode of Kv1.2 that mimics the functional outcomes of extracellular reducing conditions, and enhanced sensitivity to extracellular reducing agents. In contrast, shRNA-mediated knockdown of endogenous LMAN2 in cell lines reduced Kv1.2 redox sensitivity and gating variability. Kv1.2 sensitivity to LMAN2 is abolished by mutation of neighboring residues F251 and T252 in the intracellular S2-S3 linker, and these also abolish redox-dependent gating changes, suggesting that LMAN2 influences the same pathway as redox for Kv1.2 modulation. In conclusion, we identified LMAN2 as a candidate regulatory protein that influences redox-dependent modulation of Kv1.2, and clarified the structural elements of the channel that are required for sensitivity.

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There is sparse published information on computed tomographic (CT) characteristics of canine gastrointestinal tumors. The purposes of this multi-center, retrospective, descriptive study were to describe the CT features of histologically-confirmed canine gastrointestinal spindle cell, epithelial, and round cell tumors and, when available, describe the corresponding ultrasound findings. The inclusion criteria were as follows: availability of pre-and post-contrast CT study, and a histopathological diagnosis of the lesions. Recorded parameters were tumor size, location, gastrointestinal wall layers involvement, lesion's growth and enhancement patterns, tumor margination, presence of stenosis, mineralization, ulcerations, lymphadenopathy, or other lesions in the abdomen/thorax. When available, ultrasound images were evaluated. Forty-one dogs met the inclusion criteria and had the following histological diagnoses: 21/41 (51%) spindle cells (7 leiomyomas, 14 leiomyosarcomas/gastrointestinal stromal tumors (GISTs)), 13/41 (32%) epithelial (adenocarcinoma), and 7/41 (17%) round cell (lymphoma) tumors. The growth pattern was concentric, eccentric, and mixed in epithelial, spindle cell, and round cell tumors, respectively. Spindle cell tumors had the largest main volume and involved the outer gastrointestinal layer with an unaffected inner layer. Leiomyosarcomas/GISTs showed irregular margins compared to leiomyomas. Only lymphomas showed multifocal gastrointestinal involvement. Nine carcinomas and six spindle cell tumors caused partial stenosis with secondary sub-obstruction. Mineralizations were more frequent in spindle cell tumors (10/21) and absent in lymphomas. Lymphadenomegaly was widespread in lymphomas, regional in leiomyosarcomas-GISTs and adenocarcinomas, and absent in leiomyomas. The reported CT features may be useful in prioritizing the differential diagnosis between spindle cell, epithelial, and round cell tumors, similar to those reported on ultrasound.

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Arc discharge single walled carbon nanotubes were processed by acid treatment, dispersion in a Pluronic F68 block copolymer aqueous solution and centrifugation. The as-prepared material was characterized by transmission electron microscopy, X-ray diffraction and Raman spectroscopy, showing an important degree of debundling as well as the removal of most of the graphitic and metallic impurities from pristine nanotubes. The nanotube-Pluronic material was integrated into an advanced trifunctional epoxy resin, triglycidyl p-aminophenol, using 4,4'-diaminodiphenylsulfone as the curing agent. The material was incorporated into the epoxy system (0.1, 0.25, 0.50, 1.0, 2.0 wt%) throughout hot magnetic stirring and ultrasonication. Curing kinetics was studied using differential scanning calorimetry, applying the Vyazovkin's isoconversional method. In the early stages of curing, the kinetic study revealed a decrease in the activation energy for samples containing Pluronic, suggesting that Pluronic induced an improvement in the mobility of reactants. The cured composites were characterized by Raman spectroscopy, thermogravimetric analysis and scanning electron microscopy. Micrographs revealed successful integration and homogeneous distribution of the nanotube-Pluronic material in the epoxy matrix, while direct integration of bare nanotubes originated aggregates and inhomogeneity.

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The effect of polyetherimide (PEI) as a compatibilizing agent on the morphology, thermal, electrical and dynamic mechanical properties of poly(ether ether ketone) (PEEK)/single-walled carbon nanotube (SWCNT) nanocomposites, has been investigated for different CNT loadings. After a pre-processing step based on ball milling and pre-mixing under mechanical treatment in ethanol, the samples were prepared by melt extrusion. A more homogeneous distribution of the CNTs throughout the matrix is found for composites containing PEI, as revealed by scanning electron microscopy. Thermogravimetric analysis demonstrates an increase in the matrix degradation temperatures under dry air and nitrogen atmospheres with the addition of SWCNTs; the level of thermal stability of these nanocomposites is maintained when PEI is incorporated. Both differential scanning calorimetry and synchrotron x-ray scattering studies indicate a slight decrease in the crystallization temperatures of the compatibilized samples, and suggest the existence of reorganization phenomena during the heating, which are favoured in the composites incorporating the compatibilizer, due to their smaller crystal size. Dynamic mechanical studies show an increase in the glass transition temperature of the nanocomposites upon the addition of PEI. Furthermore, the presence of PEI causes an enhancement in the storage modulus, and hence in the rigidity of these systems, attributed to an improved interfacial adhesion between the reinforcement and the matrix. The electrical and thermal conductivities of these composites decrease with the incorporation of PEI. Overall, the compatibilized samples exhibit improved properties and are promising for their use in industrial applications.

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Silver exchanged molecular sieves ETS-10 (Ag-ETS-10) and mordenite (Ag-mordenite) were dehydrated under vacuum at temperatures between 100 degrees C-350 degrees C. Changes in the state of the silver were studied using X-ray photoelectron spectroscopy (XPS). Silver cations in titanosilicate Ag-ETS-10 are fully reduced to Ag(0) at temperatures as low as 150 degrees C. The characteristic features of the XPS spectrum of silver in this Ag-ETS-10 species correspond to only metallic silver. The signal for metallic silver is not observed in the XPS spectrum of aluminosilicate Ag-mordenite, indicating that silver cations are not reduced, even after heating to 350 degrees C.

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In a longitudinal, prospective study, 95 children born to mothers who used cocaine and other drugs during pregnancy and 75 matched, nonexposed children born to mothers who had no evidence of alcohol or illicit substance use during pregnancy were evaluated for cognitive and behavioral outcome at 6 years of age. Prenatal exposure to cocaine and other drugs had no direct effect on the child's cognitive outcome (measured as IQ), but it had an indirect effect as mediated through the home environment. However, prenatal exposure to cocaine and other drugs did have a direct effect on the child's behavioral characteristics at 4-6 years of age, with the home environment having little impact. This study helps us to understand the fragile interaction of biological and environmental factors affecting the cognitive and behavioral development of children prenatally exposed to cocaine and other drugs.

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OBJECTIVE: To compare and ascertain the suitability for endovascular aortic graft fixation of the Palmaz stent, the Strecker stent, the modified Gianturco-Z stent, the Wallstent and a new stent made of the shape memory alloy nitinol. DESIGN, SETTING AND MATERIALS: In vitro studies using a simple tensiometer to assess the forces required to distract each stent from porcine aorta; and using a high-pressure, pulsatile-flow pump to measure flow rates required to dislodge stents holding grafts within porcine aortas, with assessment using endovascular ultrasound. RESULTS: The Palmaz, the modified Gianturco-Z and the nitinol stents resisted significantly greater distraction forces than the Wallstent, but endovascular ultrasound examination revealed that the modified Gianturco-Z stent was seen to move away from the aortic wall at high flow rates precluding adequate fixation. The Strecker stent could not be assessed using these techniques. CONCLUSIONS: A nitinol stent may be suitable for aortic graft fixation, has characteristics similar to the Palmaz stent and has shape memory effect which may overcome the difficulties of introduction of wider diameter stents through narrow arteries.

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The inhibitory effects of nonoptimal temperature and nonoptimal pH on F-type conjugal transfer were found to be synergistic. This finding is briefly discussed in an environmental context.

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The conjugal transfer of R-plasmids is known to occur at temperatures above 22 degrees C. We found that R1drd-19 is transferable below 22 degrees C, and we discuss this finding in the context of plasmid transfer in environmental waters.

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A detailed case study of a B cell acute lymphocytic leukaemia (ALL) is described. Ultrastructurally the neoplastic cells resembled other cases of ALL studied. The majority of the neoplastic cells had detectable surface IgGlambda and receptors for Fcgamma while a majority of the cells had receptors for the C3 component of complement. Neoplastic cell preparations were able to synthesize IgGlambda with a surplus of free lambda chains. This case did not respond to treatment, and death ensued within 36 h of presentation. The clinical and laboratory findings are discussed with respect to other cases of ALL.

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Urinary glycosaminoglycan excretion was studied in 24 cases of disseminated neoplasm, 12 of which had unequivocal evidence of skeletal involvement. Urinary hydroxyproline, cetylpyridinium chloride (CPC)-precipitable uronic acid, and CPC-precipitable hexosamine were expressed as a ratio to urinary creatinine. Glycosaminoglycans contained in urine concentrated x 1000 by vacuum-dialysis were separated by electrophoresis on cellulose acetate and stained with alcian blue. Of the 12 cases with clear evidence of skeletal involvement, eight (66%) showed elevation of serum alkaline phosphatase, five (42%) showed elevation of urinary hydroxyproline, and three (25%) showed elevation of urinary uronic acid. It is concluded that urinary uronic acid is not a sensitive index of skeletal involvement in disseminated neoplasm. The most striking feature of the study was the identification of a well-defined fraction indist inguishable from hyaluronic acid in seven (58%) of the cases with evidence of skeletal involvement. Hyaluronic acid is not normally identifiable in adult human urine. The hyaluronic acid excretors showed more consistent biochemical evidence of bone disease (elevation of serum alkaline phosphatase and urinary hydroxyproline) than the non-excretors. The possibility that the urinary hyaluronic acid is derived from degradation of skeletal hyaluronic acid is discussed. An alternative explanation is that the hyaluronic acid is derived from neoplastic cells as part of a reversion of glycosaminoglycan synthesis to a more ;fetal' state, a glycosaminoglycan counterpart of the production of oncofetal antigens by neoplastic cells.

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