Design of semi-interpenetrating networks based on poly(ethyl-2-cyanoacrylate) and oligo(ethylene glycol) diglycidyl ether

The synthesis of semi-interpenetrating networks (SIPN) based on linear poly(ethyl 2- cyanoacrylate) (PECA) and oligo(ethylene glycol) diglycidyl ether (OEGDG) based polymer networks was motivated by the hypothesis that the brittleness of polycyanoacrylates may be overcome by incorporating them into a polymer network architecture. A sequential synthetic route was applied, in which first PECA was prepared by anionic polymerization. Subsequently, OEGDG was crosslinked with different anhydrides and curing catalysts to form networks with hydrolyzable ester bonds and interpenetrating PECA. These SIPNs showed a low water uptake compared to other polyether based networks. Some of the obtained materials were transparent and exhibited a great flexibility, which was maintained also after 24 h of immersion in water and subsequent drying. Such networks could be components of future stimuli-sensitive material systems

Hydrolytic Degradation Behavior of Poly(rac-lactide)-block-poly(propylene glycol)-block-poly(rac-lactide) Dimethacrylate Derived Networks Designed for Biomedical Applications

For polymer-based degradable implants, mechanical performance and degradation behavior need to be precisely controlled. Based on a rational design, this work comprehensively describes the properties of photo-crosslinked polymer networks prepared from poly(rac-lactide)-block-poly(propylene glycol)-block-poly(rac-lactide) dimethacrylate precursors during degradation. By varying the length of poly(rac-lactide) blocks connected to a central 4?kDa polyether block, microphase separated networks with adjustable crosslinking density, hydrophilicity/hydrophobicity ratio, thermal, and mechanical properties are obtained. The materials are characterized by a low water uptake, controlled mass loss, and slowly decreasing wet-state E moduli in the kPa range

New graft copolymers of hyaluronic acid and polylactic acid: Synthesis and characterization

New graft copolymers have been synthesized, using hyaluronic acid (HA) as a hydrophilic backbone and polylactic acid (PLA) as an aliphatic polyester in order to obtain new polymeric derivatives of HA able to hydrophobically associate in an aqueous medium. Hyaluronic acid with low molecular weight was made soluble in organic solvent by transformation to its tetrabutylammonium (TBA) salt. Using the HA-TBA derivative, the reaction was performed in dimethylsulfoxide adding as a reagent the N-hydroxysuccinimide derivative of PLA. Two HA-PLA graft copolymers have been synthesized and characterized by FT-IR, H-1 NMR spectroscopy and gel permeation chromatography. The interaction between these samples and an aqueous medium has been evaluated by rheological measurements. The obtained data evidenced that both HA-PLA graft copolymers show in aqueous medium a clear tendency for hydrophobic interaction dependent on the amount of PLA chains linked to the HA backbone. (c) 2006 Elsevier Ltd. All rights reserved

Progressive visceral leishmaniasis misdiagnosed as cirrhosis of the liver: a case report

<p>Abstract</p> <p>Introduction</p> <p>Visceral leishmaniasis is a potentially life-threatening infectious disease which is caused by parasites of the genus <it>Leishmania</it> and characterized in most cases by the presence of fever as well as signs and symptoms similar to those found in liver cirrhosis.</p> <p>Case presentation</p> <p>In this case report we describe the history of a 50-year-old Caucasian man incorrectly diagnosed as having hepatitis C virus-associated liver cirrhosis, with a massive weight loss of around 100 kg during the previous 2 years. However, suspecting a lymphoproliferative disorder, we were able to make a correct diagnosis of visceral leishmaniasis by bone marrow examination. After a course of therapy with Liposomal Amphotericin-B the patient recovered and now, 20 months post-treatment, he is well and has regained a good part of the lost weight.</p> <p>Conclusions</p> <p>This case taught us that patients with massive splenomegaly, even with a diagnosis of liver cirrhosis, should be investigated for infectious or lymphoproliferative diseases.</p

Inulin-iron complexes: A potential treatment of iron deficiency anaemia

The aim of this work was that to synthesize macromolecular derivatives based on inulin able to complex iron and useful in the treatment of iron deficiency anaemia. Carboxylated or thiolated/carboxylated inulin derivatives were obtained by single or double step reactions, respectively. The first one was obtained by reaction of inulin (INU) with succinic anhydride (SA) alone obtaining INU-SA derivative; the second one was obtained by the reaction of INU with succinic anhydride and subsequent reaction of INU-SA with cysteine; both derivatives were treated with ferric chloride in order to obtain the INU-SA-Fe-III and INU-SA-Cys-Fe-III complexes. Both complexes showed an excellent biodegradability in the presence of inulinase and pronounced mucoadhesion properties; in particular, thiolated derivative INU-SA-Cys showed greater mucoadhesive properties than polyacrylic acid chosen, as a positive reference polymer, and a good iron release profile in condition mimicking the intestinal tract. These results suggest the potential employment of such systems in the oral treatment of iron deficiency anaemia or as supplement of iron in foods. (c) 2007 Elsevier B.V. All rights reserved

Verifying the reliability of historical sources through an archaeometric study

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Low temperature specific heat of densified vitreous B2O3

Low temperature specific heat of densified vitreous B2O

A complex case of fatal calciphylaxis in a female patient with hyperparathyroidism secondary to end stage renal disease of graft and coexistence of haemolytic uremic syndrome

Background. Calciphylaxis is a potentially fatal complication of persistent secondary hyperparathyroidism; its cause is still not clear. Unfortunately there is no close relation in severity of clinical picture, serological and pathological alteration. For this reason the prognosis is difficult to establish. Administration of sodium thiosulphate may reduce the precipitation of calcium crystals and improve the general clinical conditions before surgical parathyroidectomy, which seems the only therapeutic approach able to reduce the mortality risk in these patients. Methods and Results. A 60 year old female patient suffering from End Renal Stage Disease, on haemodialysis from 2001 due to the onset of haemolytic uremic syndrome, underwent a kidney transplant in April 2008. After transplantation there was a recurrence of the haemolytic uremic syndrome, with temporary worsening of the graft. Six months later there was a definite loss of graft and return to dialysis treatment. On April 2010 a severe systemic calciphylaxis related to secondary hyperparathyroidism was diagnosed. The patient underwent parathyroidectomy but, because of the unimproved clinical picture, treatment with sodium thiosulphate was initiated. There was only improvement in cutaneous lesions. The worsening general clinical condition of the patient caused death due to general septic complications. Conclusions. The coexistence of haemolytic uremic syndrome and secondary hyperpathyroidism makes the prognosis poor and, in this case, therapy, which counteracts calcium crystals precipitation, has no effect. Preventive parathyroidectomy can be considered as the only possible treatment

Low frequency Raman scattering of densified vitreous B2O3

Low frequency Raman scattering and of densified vitreous B2O