Nanofocusing on circularly distributed tapered metallic waveguides by means of plasmonic vortex lenses.

We report our experimental results on the nanofocusing effect at the apex of planar nanotips placed at the center of a plasmonic vortex lens (PVL). PVLs are helical gratings that are able to generate surface plasmon polaritons (SPPs) carrying orbital angular momentum. A specific design allows us to couple the PVL with nanostructures placed at its center. The proposed configuration allows a simultaneous nanofocusing effect on four facing planar nanotips, showing efficient condensation of SPPs at the metal-air interface toward the end point of the tips. An optimized fabrication process allows us to prepare high-quality structures with a sharp tip apex. Near-field scanning optical microscopy has been used to demonstrate the nanofocusing effect.

Development of a complete plasmonic grating-based sensor and its application for self-assembled monolayer detection.

This work presents an integrated plasmonic biosensing device consisting of a one-dimensional metallic lamellar grating designed to exploit extraordinary transmission of light toward an underlying silicon photodetector. By means of finite element simulations, the grating parameters have been optimized to maximize the light transmission variation induced by the functionalization of the gold nanostructures. An optimized grating was fabricated using an electron beam process and an optoelectronic test bench suitable for sample tests was developed. A clear difference in the grating transmitted light due to surface functionalization was observed in presence of TM polarized illumination.

Short and long range surface plasmon polariton waveguides for xylene sensing.

Nanostructured plasmonic sensors are fabricated as sinusoidal surface plasmon metallic gratings (SPGs) embedded in a functional and porous hybrid sol-gel material, phenyl-bridged polysilsesquioxane (ph-PSQ). The metal layer is in contact with the environment through the sol-gel film, which works as sensitive element, changing its dielectric properties upon interaction with aromatic hydrocarbons. The combination of sensitivity, transparency and patternability offered by ph-PSQs gives the exceptional possibility to fabricate innovative optical sensors with straightforward processes. An embedded SPG is a thin metal slab waveguide, in which the surface plasmon polaritons (SPPs) at the two metal-dielectric interfaces superpose, resulting in two physical coupled modes: the long range SPPs (LRSPPs) and the short range SPPs (SRSPPs). An extended experimental and theoretical characterization of the optical properties of the plasmonic device was performed. The sensor performance was tested against the detection of 30 ppm xylene, monitoring the influence of the target gas on the SPPs modes. A reversible red-shift of the reflectance dips of both LRSPP and SRSPP resonances in the 1.9-2.9 nm range was observed and correlated to the interaction with the analyte. An enhancement in sensitivity associated with the rotation of the grating grooves with respect to the scattering plane (azimuthal rotation) was verified within the experimental errors. Collected data are compatible with theoretical predictions assuming a variation of the film refractive index of 0.011 ± 0.005.

Extraordinary optical transmission in one-dimensional gold gratings: near- and far-field analysis.

One-dimensional arrays of nanoslits fabricated on silicon nitride membranes show extraordinary optical transmission. Optical characterization techniques have been used to characterize the transmission spectra and the near-field optical configuration. Experimental results have been compared with numerical simulations in order to elucidate the different modes of light propagation. Near- and far-field optical distribution is studied as a function of the polarization of light.

Polarization independence of extraordinary transmission trough 1D metallic gratings.

Extraordinary optical transmission of 1D metallic gratings is studied. Experimental samples are fabricated by means of Electron Beam Lithography. The optical characterization is focused on far field transmission properties and in particular on polarization dependence of the incident light. A peculiar symmetry in transmission spectra at different polarization angles is shown; this symmetry is studied both experimentally, and numerically with FEM method. A comparison between numerical and experimental data is provided.

Absorption profile modulation by means of 1D digital plasmonic gratings.

Optical simulations of 1D digital plasmonic gratings on a Silicon substrate are performed by means of the Finite Elements Method and a modal analysis. The different mechanisms of transmission of the light are elucidated. The absorption profile in Silicon can be modulated and controlled changing the geometry. Configuration maps allow to determine the different optical regimes. Surface Plasmon Polaritons and cavity-mode resonances are shown to be effectively exploitable to enhance NIR-light absorption in different shallower regions of the underlying Silicon.

Interferon alfa-2a therapy in cryoglobulinemia associated with hepatitis C virus.

BACKGROUND: Essential mixed cryoglobulinemia is frequently associated with hepatitis C virus (HCV) infection. A beneficial effect of interferon alfa therapy has been reported, but we do not know whether the antiviral activity of the drug affects the clinical and biochemical manifestations of disease. METHODS: In a prospective randomized, controlled trial, we studied 53 patients with HCV-associated type II cryoglobulinemia. A group of 27 patients received recombinant interferon alfa-2a thrice weekly at a dose of 1.5 million units for a week and then 3 million units thrice weekly for the following 23 weeks. The 26 control patients did not receive anything apart from previously prescribed treatments. All patients were then followed for an additional 24 to 48 weeks. RESULTS: Interferon was usually well tolerated, but it was permanently discontinued in two patients because of atrial fibrillation and depression. Two of the 26 patients in the control group were lost to follow-up. After the treatment period, serum HCV RNA was undetectable in 15 of the remaining 25 patients who received interferon alfa-2a, but in none of the controls. In comparison with the control group, the 15 patients with undetectable levels of HCV RNA in serum had significant improvement in cutaneous vasculitis (P = 0.04) and significant decreases in serum levels of anti-HCV-antibody activity (P = 0.007), cryoglobulins (P = 0.002), IgM (P = 0.002), rheumatoid factor (P = 0.001), and creatinine (P = 0.006). After treatment with interferon alfa-2a was discontinued, viremia and cryoglobulinemia recurred in all 15 HCV RNA-negative patients. On resumption of treatment, three of four patients had a virologic, clinical, and biochemical response. CONCLUSIONS: The therapeutic efficacy of interferon alfa-2a in HCV-associated cryoglobulinemia is closely related to its antiviral activity, thus supporting the idea that HCV infection may be a cause of this disease.

Platelet-activating factor receptor blocking reduces proteinuria and improves survival in lupus autoimmune mice.

Platelet-activating factor (PAF) has been suggested recently to play an important role in immune glomerulonephritis, favoring the formation of immune deposits in glomeruli and contributing to the local inflammatory reaction. Here we sought to investigate whether urinary PAF excretion was modified in New Zealand Black x New Zealand White mice a model of genetically determined immune complex disease which mimics systemic lupus in humans and whether changes in PAF urinary excretion values correlated with the extent of proteinuria. To clarify the possible "in vivo" relevance of these findings we evaluated whether PAF receptor antagonist has any influence on the evolution of renal disease and survival of these mice. Our results showed that: 1) in lupus mice urinary PAF excretion increased progressively with age in New Zealand Black x White; 2) the increase in PAF excretion correlated with the severity of proteinuria; and 3) the chronic administration of a PAF receptor antagonist [L-659,989 [(+/- )-trans-2-(3-methoxy-5-methylsulfonyl-4-propoxyphenyl)-5- (3,4,5-trimethoxyphenyl)tetrahydrofuran]] starting from 26 weeks of age significantly delayed the onset of proteinuria and prolonged survival.

Tissue plasminogen activator therapy of rabbit nephrotoxic nephritis.

To study the efficacy of tissue plasminogen activator (PA) therapy to prevent deteriorating renal function in experimental proliferative glomerulonephritis we used a model of nephrotoxic nephritis induced in rabbits by injection of antiglomerular basement membrane antiserum. Saline or recombinant tissue plasminogen activator (rt-PA, 1.3 mg/kg body weight) was infused daily for 7 days starting from day 7 after the injection of antiglomerular basement membrane antiserum when the disease had been already triggered. Animals were killed on day 14. Rabbits given saline had abundant deposits of fibrin and crescents in about 67% of glomeruli. rt-PA significantly protected animals from glomerular fibrin deposition and crescent formation with respect to saline-treated animals. Renal function measured as creatinine clearance was dramatically impaired in rabbits given saline. Treatment with rt-PA ameliorated the renal function impairment of nephrotoxic nephritis. rt-PA did not produce a systemic fibrinolytic state as indicated by alpha 2-antiplasmin level measurement. These results suggest that tissue PA may have important implications in preventing renal function deterioration in humans with crescentic glomerulonephritis and fibrin depositions.

[Acquired renal cystic disease in uremia: a prevalence survey]. / Doença renal cística adquirida da uremia: estudo de prevalência.

The acquired cystic disease of the kidney (ACDK) occurs in uremic patients before and during dialysis treatment. It has been defined as a disease with multiple acquired cystic lesions in patients with advanced renal failure. We evaluated its prevalence in a group of 94 uremic patients employing ultrasonographic examinations. Eighteen patients were not on dialysis treatment (group I) and 76 patients were undergoing hemodialytic treatment (group II). The prevalence of ACDK in groups I and II was 16.7% and 39.5% respectively. There is a noteworthy progression in the prevalence of the disease as the patients are kept alive by dialysis treatment. Primary renal disease, age and sex were not important factors in the disease's prevalence.

Ecobiometria do olho fetal / Fetal eye ultrasonic measurement

Foram realizadas mediçöes do diâmetro transversal equatorial ocular em 224 fetos de gestantes normais utilizando-se um ecógrafo Toshiba equipado com transdutor de 2,4 MHz. A idade gestacional dos fetos oscilou entre 12 e 19 semanas. O diâmetro ocular médio variou de 3,3 mm na 12ª semana até 18,9 mm na 39ª. O crescimento ocular mostrou-se mais rápido na primeira metade da gestaçäo diminuindo paulatinamente até chegar a um mínimo nas últimas semanas. Com os dados obtidos foi posssivel construir nomogramas aplicáveis ao nosso meio, que poderäo auxiliar na detecçäo intra-uterina de diversas patologias

Cyclosporin-induced endothelial cell injury.

The administration of Cyclosporin-A (CyA) to animals and humans may induce an arteriolar damage. It has also been reported that CyA in some instances may cause an hemolytic uremic-like syndrome. This is a syndrome of vascular damage with thrombotic occlusions of the microcirculation. Endothelial injury is considered the first event in the pathogenetic cascade leading to hemolytic-uremic syndrome. We have used bovine aortic endothelial cells in culture to address the issue of CyA-induced arteriolar damage. Exposure of endothelial cells to different concentrations of CyA induced a time- and dose-dependent cell injury in vitro. The damage induced by CyA was characterized by an early cell detachment from culture substrate followed by cell lysis as documented by the increase in lactate dehydrogenase (LDH) and 51Cr release. Both detachment and lysis were negligible after short-term incubation of 1 microM CyA with endothelial cells. One micromolar CyA only induced lysis if incubations were prolonged above 6 hours. Ten and 50 microM CyA both induced marked endothelial cell detachment and lysis; lysis started 3 hours after incubation of endothelial cells with CyA and was maximal at the end of 24 hours incubation. CyA-induced injury was associated with dose- and time-dependent increase in prostacyclin and thromboxane A2 release by endothelial cells exposed to CyA independently from the concentrations of CyA used. CyA-induced generation of prostacyclin and thromboxane A2 was inhibited when the incubations were performed in the presence of aspirin (500 microM). These studies indicate that CyA exerts a direct cytotoxic effect on endothelial cells and might help in understanding the pathogenesis of CyA-induced vascular damage.

Sarcoma de Kaposi gastrico. / Gastric Kaposi's sarcoma

Um caso de sarcoma de Kaposi, com envolvimento do estomago e apresentado.Ocasionalmente o trato gastrointestinal e comprometido. Sao comentados os aspectos clinicos, radiologicos e patologicos do Sarcoma de Kaposi