PEG-crosslinked-chitosan hydrogel films for in situ delivery of Opuntia ficus-indica extract.

In the present study, chitosan-based wound dressings loaded with the extract of Opuntia ficus-indica (OPU) were prepared. OPU is known for its capability to accelerate skin injury repair. Chitosan (Ch) was crosslinked with a low molecular weight diepoxy-poly(ethylene glycol) (diePEG), and hydrogel films with different Ch/PEG composition and OPU content were prepared by casting. The occurrence of crosslinking reaction was confirmed by FTIR spectroscopy. FTIR and DSC analysis suggested that ionic interactions occur between chitosan and OPU. Tensile tests evidenced that the crosslinking caused a decrease of Young's modulus, which approaches the value of the human skin modulus. Swelling characteristics, water vapor transmission rate, and release kinetics demonstrated that these films are adequate for the proposed application. Finally, a scratch test on a keratinocytes monolayer showed that the rate of cell migration in the presence of OPU-loaded samples is about 3-fold higher compared to unloaded films, confirming the repairing activity of OPU.

Spray-by-spray in situ cross-linking alginate hydrogels delivering a tea tree oil microemulsion.

In this paper we propose an in situ forming ionically cross-linked alginate (Alg) hydrogel delivering a Tea Tree Oil microemulsion (MeTTO) and potentially useful as an advanced dressing for infected wounds. Alg hydrogels were prepared by a spray-by-spray deposition method with the aim to minimize the discomforts during application. From pseudoternary phase diagrams, it was found that proper combination of TTO, water, polysorbate 80 and ethanol gave stable spherical MeTTO with good antimicrobial activity. On this basis, MeTTO at 20% TTO was selected for further inclusion in an Alg hydrogel prepared by alternating sprays of Alg/MeTTO and calcium chloride solutions. Homogeneous dispersion of MeTTO inside cross-linked Alg was assessed by different macroscopic and microscopic methods demonstrating the superior propensity of MeTTO to be integrated in the water-based hydrogel as compared to TTO. Antimicrobial effect of Alg/MeTTO hydrogels on Escherichia Coli strains was remarkable, highlighting the potential of the system as bioactive wound dressing.

Water buffalo mozzarella cheese stored in polysaccharide-based gels: correlation between prolongation of the shelf-life and physicochemical parameters.

An innovative packaging system has been developed, based on natural gels, that has shown the peculiar characteristic to strongly increase the shelf life of water buffalo Mozzarella cheese. To explain the mechanism of action of the gel, measurements of Ca and Na in the cheese and in the storage liquid were carried out, together with pH determination. A correlation has been found between the constant level of Ca and pH in the cheese and the prolongation of nutritional characteristics; in fact, both parameters diminish significantly in the absence of gel. At the same time, the weight of the cheese in gel remained constant for as long as 30 d. Confocal laser microscopy gave direct evidence of the persistent physical structure of proteins and lipids of Mozzarella when stored in gel.

Natural polysaccharide-based gels for dairy food preservation.

The innovative packaging systems described in the present work, based on natural gels, have been shown to increase the shelf life of the Mozzarella cheese, without adding any chemical substance and without thermal procedures. Physical, physicochemical, microbiological, analytical, and mechanical analyses were used to monitor the quality of the cheese as a function of storage type and storage time. In particular, microbiological analysis confirmed that the characteristics of the Mozzarella cheese stored at 4 degrees C in gel are maintained for more than 15 d, whereas samples stored in the mother solution lost important characteristics after 5 d. A penetration test (texture) confirmed that the Mozzarella cheese preserved in the gel maintained mechanical properties similar to those of the fresh product, even after storage for 30 d at 4 degrees C.

Novel graft PLLA-based copolymers: potential of their application to particle technology.

This study describes the synthesis of novel biodegradable graft copolymers based on a backbone of poly (L-lactic acid) (PLLA) on which short blocks of polyacrylamide (PAcr) were grafted. Preliminary results of their potential in the field of controlled-release technologies also have been reported. The copolymers have been synthesized through the radical polymerization of acrylamide initiated by a peroxide in the presence of PLLA. Two different methodologies of synthesis, namely, in solution and in emulsion, have been tested. The structure of the copolymers was studied by (1)H-NMR and infrared spectroscopy and by differential scanning calorimetry (DSC) and cytotoxicity tests were conducted to assess their biocompatibility. The copolymers were used to prepare particles by the emulsion-solvent evaporation technique. The shapes and dimensions of the particles were dependent on the polymer type and concentration used. The surfaces of the particles were modified by the presence of polyacrylamide residues, as demonstrated by zeta-potential measurements. The release behavior of the particles was assessed by encapsulating rhodamine B as the model compound. The release was faster for the particles prepared by the grafted polymer as a consequence of its increased hydrophilicity. Based on these novel biomaterials, preliminary results suggest a potential of the particles for peroral or parenteral drug delivery.

Light and ultrastructural studies in sural biopsies of the pseudopolyneuropathic form of ALS.

The aim of this work was to study the neuropathological picture of the sural nerve in the pseudopolineuropathic form of A.L.S. Five patients were considered: in all cases the clinical and electromyographic follow-up excluded other diseases. EMG-studies were repeatedly performed: they showed the progressive evolution of the spinal anterior horn cell pathology from lower spinal to cervical levels. The sural nerve was processed according to the procedure used in our laboratory for light and ultrastructural examination. Quantitative analysis of myelinated fiber density was carried out on photographic enlargement and reported on histograms. The light and ultrastructural examination showed a severe loss of myelinated fibers; the decrease affected all types of fibers, but predominated in the largest ones. In the axons there was an increase of mitochondria, dilation of the small vesicles and increase in the number of neurofilaments. It is our opinion that all histopathologic data obtained in the sural nerve biopsy in this form of A.L.S. reveal a clear involvement of the sensory neurons of the spinal ganglia and the results can be useful for the study of precocius lesions in the A.L.S.

Dementia-peripheral neuropathy during combined deficiency of vitamin B12 and folate. Light microscopy and ultrastructural study of sural nerve.

We present a case of a 56 year old woman who, in consequence of repeated surgical resections of the small bowel, developed a slowly progressive and mainly motor polyneuropathy affecting the lower limbs. The polyneuropathy due to a combined deficiency of vitamin B12 and folate, was associated with intellectual deterioration, involving especially the mnesic functions. Light microscopy and ultrastructural study of sural nerve revealed: marked reduction of every order of myelinated fibers: aspects of wallerian-like myelin degeneration; various stages of myelin leaflet delamination into the cytoplasm of Schwann cells and/or macrophages; lack of alterations attributable to a primary axonal degeneration. The morphological results suggest a primary demyelination, followed secondarily by either axonal changes or some aspects of wallerian-like degeneration.

Peripheral neuropathy in course of progressive systemic sclerosis. Light and ultrastructural study.

Progressive systemic sclerosis (PSS) is a chronic inflammatory disease of the connective tissue with involvement of the skin and other organs. The disease is characterized by an abnormal accumulation of collagen in all tissues and by microangiopathy. The involvement of the peripheral nervous system during PSS is very unusual and few cases are reported in the literature. A morphological study on the neuropathy associated with sclerodermia has been performed in rare cases. In this paper we demonstrate the role that the vascular lesions have in the pathogenesis of neuropathy during scleroderma. In particular, the primary role of the peripheral microangiopathy during PSS (observed in different clinical cases) is verified.