PLGA/Ag nanocomposites: in vitro degradation study and silver ion release

New nanocomposite films based on a biodegradable poly (DL-Lactide-co-Glycolide) copolymer (PLGA) and different concentration of silver nanoparticles (Ag) were developed by solvent casting. In vitro degradation studies of PLGA/Ag nanocomposites were conducted under physiological conditions, over a 5 week period, and compared to the behaviour of the neat polymer. Furthermore the silver ions (Ag⁺) release upon degradation was monitored to obtain information on the properties of the nanocomposites during the incubation. The obtained results suggest that the PLGA film morphology can be modified introducing a small percentage of silver nanoparticles that do not affect the degradation mechanism of PLGA polymer in the nanocomposite. However results clearly evinced the stabilizing effect of the Ag nanoparticles in the PLGA polymer and the mineralization process induced by the combined effect of silver and nanocomposite surface topography. The Ag⁺ release can be controlled by the polymer degradation processes, evidencing a prolonged antibacterial effect.     

Selective CO-oxidation over Ru-based catalysts in H2-rich gas for fuel cell applications

Topics in Catalysis - Ru-based catalysts supported on A zeolites and alumina were synthesised, characterised (XRD, SEM-EDS, TPR) and tested under realistic conditions for the preferential oxidation...     

Prevalence of hepatitis G virus RNA in French blood donors and recipients

The results of treatment of 419 patients with endometrial sarcoma are presented. Five-year survival was 42.7% and it appeared to depend on histological pattern substantially: leimyosarcoma--49.5; endometrial stromal sarcoma--43.5; mixed mesodermal tumors--40.2% (carcinosarcoma included--26.4%). With localized tumors (stage I) of all histological patterns, survival was 3 times (58.9%) that in cases of cervix uteri involvement (19.4%). The recommendations for treatment of endometrial sarcoma are given: uterine extirpation with adnexa in patients with leimyosarcoma and a modified extended extirpation of the uterus for mixed mesodermal tumors. Radiotherapy is recommended for all patterns of tumor, except for leimyosarcoma. Adjuvant chemotherapy will increase the chances of better prognosis.     

The role of corn starch,amaranth flour,pea isolate,and Psyllium flour on the rheological properties and the ultrastructure of gluten-free doughs

The removal of gluten from bakery products, in order to produce foods (mainly based on gluten-free cereal flours and starch) for people with celiac disease, impairs dough’s capacity to properly develop during leavening and baking. The main aim of this research was to produce and evaluate some experimental gluten-free (GF) doughs containing different levels of corn starch, amaranth flour (to enhance the nutritional benefits), pea isolate (to increase the protein content) and Psyllium fiber (as thickening agent and fiber source) in order to study the influence of the different ingredients on the rheological properties and on the ultrastructure of the doughs. Psyllium fiber generally enhanced the physical properties of the doughs, due to the film-like structure that it was able to form, and the most complex among the experimental formulations looked promising in terms of final bread technological and nutritional quality even when compared to two different commercial GF mixtures.     

Cytolytic T cells with Th1-like cytokine profile predominate in retroorbital lymphocytic infiltrates of Graves' ophthalmopathy

Lymphocytic infiltration of muscular and connective tissues of the retroorbital (RO) space is a histological hallmark of Graves' ophthalmopathy (GO). We have characterized some phenotypical and functional features of T cells derived from RO infiltrates of four GO patients who were submitted to orbital decompression. Fragments of RO tissue were cultured for 7 days in IL-2-conditioned medium in order to generate T cell lines of in vivo activated T cells. Phenotypical analysis of freshly isolated peripheral blood (PB) lymphocytes both from patients and four healthy controls showed a predominance of CD4+ T cells (CD4/CD8 ratios 1.9:2.5), whereas RO-derived T cell lines displayed almost equal proportions of CD4+ and CD8+ cells (CD4/CD8 ratios 0.9:1.2). RO T cell lines and PB T cells from patients and controls were then cloned using a high-efficiency cloning procedure. The phenotypical and functional features of 153 T cell clones (TCC) derived from RO infiltrates were examined and compared with those of 166 and 236 TCC derived from the PB of patients and controls, respectively. CD4/CD8 ratios ranged from 0.8-1.4 in the series of RO-derived TCC and from 1.9-2.2 in the corresponding series of PB-derived TCC. Assessment of lectin-dependent cytolytic activity showed similar proportions of cytotoxic clones in TCC derived from the PB of patients (37%) and controls (38%); most of the cytolytic TCC was CD8+. In contrast, the proportion of cytolytic RO TCC was markedly higher (106/153 = 69%), including 100% of CD8+ and the majority (59/79 = 75%) of CD4+ clones. When compared to TCC derived from the PB of both patients and controls, RO TCC showed remarkably high proportions of both CD8+ and CD4+ clones with a Th1-like cytokine profile, as documented by their ability to secrete IL-2, IFN-gamma, and tumor necrosis factor-alpha (TNF-alpha), but not IL-4 or IL-5. This study provides evidence that cytolytic T cells with Th1 profile of cytokine production predominate in RO infiltrates of GO, a pattern quite similar to those previously described in thyroid infiltrates of Hashimoto's thyroiditis or Graves' disease. The peculiar cytokine secretion profile of RO T cells may be of importance in the pathogenesis of both the tissue alterations and fibrogenic process observed in GO.     

Linguistic and non-linguistic abilities in a patient with early left hemispherectomy

A patient who underwent early removal of the left hemisphere because of Sturge-Weber syndrome was submitted to detailed linguistic and visuospatial batteries. The performances were compared to performances of subjects matched for age, education and IQ, but without focal cerebral lesions. Language was mildly impaired but to the same extent as in IQ controls. On the contrary, visuospatial abilities were clearly worse than in IQ controls, and the most preserved visuospatial abilities seemed to be the less sophisticated ones. Non literal comprehension of language, a function generally attributed to the right hemisphere, was intact. This same pattern, that is, preservation of language and impairment of visuospatial abilities, also seems to occur in subjects who have undergone surgical removal of the right hemisphere; in other words, the cognitive pattern seems the same regardless of which hemisphere is removed. These observations suggest that no matter which hemisphere is removed, functional reorganisation follows a hierarchical criterion which privileges the linguistic function, and the visuospatial functions most essential for independent survival.     

Sulfolobus solfataricus protein disulphide oxidoreductase: insight into the roles of its redox sites

Sulfolobus solfataricus protein disulphide oxidoreductase (SsPDO)contains three disulphide bridges linking residues C⁴¹XXC⁴⁴,C¹⁵⁵XXC¹⁵⁸, C¹⁷³XXXXC¹⁷⁸. To get information on the role playedby these cross-links in determining the structural and functionalproperties of the protein, we performed site-directed mutagenesison Cys residues and investigated the changes in folding, stabilityand functional features of the mutants and analysed the resultswith computational analysis. The reductase activity of SsPDOand its mutants was evaluated by insulin and thioredoxin reductaseassays also coupled with peroxiredoxin Bcp1 of S. solfataricus.The three-dimensional model of SsPDO was constructed and correlatedwith circular dichroism data and functional results. Biochemicalanalysis indicated a key function for the redox site constitutedby Cys155 and Cys158. To discriminate between the role of thetwo cysteine residues, each cysteine was mutagenised and thebehaviour of the single mutants was investigated elucidatingthe basis of the electron-shuffling mechanism for SsPDO. Finally,cysteine pK values were calculated and the accessible surfacefor the cysteine side chains in the reduced form was measured,showing higher reactivity and solvent exposure for Cys155.