Compact Polyelectrolyte Complexes: “Saloplastic” Candidates for Biomaterials

Precipitates of polyelectrolyte complexes were transformed into rugged shapes suitable for bioimplants by ultracentrifugation in the presence of high salt concentration. Salt ions dope the complex, creating a softer material with viscous fluid-like properties. Complexes that were compacted under the centrifugal field (CoPECs) were made from poly(diallyldimethyl ammonium), PDADMA, as polycation, and poly(styrene sulfonate), PSS, or poly(methacrylic acid), PMAA, as polyanion. Dynamic mechanical testing revealed a rubbery plateau at lower frequencies for PSS/PDADMA with moduli that decreased with increasing salt concentration, as internal ion pair cross-links were broken. CoPECs had significantly lower modulii compared to similar polyelectrolyte complexes prepared by the “multilayering ” method. The difference in mechanical properties was ascribed to higher water content (located in micropores) for the former and, more importantly, to their nonstoichiometric polymer composition. The modulus of PMAA/PDADMA CoPECs, under physiological conditions, demonstrated dynamic mechanical properties that were close to those of the nucleus pulposus in an intervertebral disk

Determination of reference values for optical properties of liquid phantoms based on Intralipid and India ink

A multi-center study has been set up to accurately characterize the optical properties of diffusive liquid phantoms based on Intralipid and India ink at near-infrared (NIR) wavelengths. Nine research laboratories from six countries adopting different measurement techniques, instrumental set-ups, and data analysis methods determined at their best the optical properties and relative uncertainties of diffusive dilutions prepared with common samples of the two compounds. By exploiting a suitable statistical model, comprehensive reference values at three NIR wavelengths for the intrinsic absorption coefficient of India ink and the intrinsic reduced scattering coefficient of Intralipid-20% were determined with an uncertainty of about 2% or better, depending on the wavelength considered, and 1%, respectively. Even if in this study we focused on particular batches of India ink and Intralipid, the reference values determined here represent a solid and useful starting point for preparing diffusive liquid phantoms with accurately defined optical properties. Furthermore, due to the ready availability, low cost, long-term stability and batch-to-batch reproducibility of these compounds, they provide a unique fundamental tool for the calibration and performance assessment of diffuse optical spectroscopy instrumentation intended to be used in laboratory or clinical environment. Finally, the collaborative work presented here demonstrates that the accuracy level attained in this work for optical properties of diffusive phantoms is reliable

Chylous ascites due to constrictive pericarditis

Chylous ascites due to constrictive pericarditis is an extremely rare clinical entity, possibly caused by the augmented lymph production and high impedance to lymph drainage due to central venous hypertension. The authors describe a patient with chylous ascites caused by constrictive pericarditis in the absence of lymphatic obstruction. Cardiac catheterization is essential for the confirmation of accurate diagnosis of constrictive pericarditis. Magnetic resonance imaging of the heart is also very helpful in the diagnosis. The patient was symptom free and his ascites and edema completely resolved after pericardiectomy

Trimethoprim/sulfamethoxazole-induced hypoglycemia in a malnourished patient with severe infection

Hypoglycemia resulting from the combination of sulfonylurea and sulfonamides is a recognized drug interaction. Hypoglycemia induced by sulfonamides alone may be encountered less frequently. Because of their structural similarities to sulfonylureas, sulfonamides are liable to facilitate hypoglycemia by increasing insulin release in susceptible individuals. Sulfonamides can potentiate the hypoglycemic effect of sulfonylurea agents when given in combination. We describe a malnourished patient with severe infection who developed hypoglycemia during high-dose trimethoprim/sulfamethoxazole therapy. Elevated C-peptide concentrations during the hypoglycemic episode indicate that hypoglycemia resulted from increased endogenous insulin secretion. As malnourished patients are prone to hypoglycemia, we suggest that they should be monitored carefully if they are on sulfonamide therapy

Attention deficit and hyperactivity disorder in HIV-infected individuals: is it associated with non-adherence to treatment?

WOS: 00044848220012