Clinical implications of endotoxin activity and Polymyxin-B hemoperfusion in critically ill patients with septic cardiomyopathy: A single-center, retrospective, observational study

BACKGROUND

To explore the association between endotoxin activity (EA) and septic cardiomyopathy (SCM), the relationship between endotoxin removal by Polymyxin-B hemoperfusion (PMX-HP) and recovery from SCM (R-SCM), and the correlation between R-SCM and the 28-day mortality in septic patients admitted to the intensive care unit (ICU).

METHODS

Observational study that included patients admitted to two ICUs of a tertiary university hospital between April 2011 and December 2019, who received PMX-HP for sepsis/septic shock. The SCM and R-SCM were assessed by transthoracic echocardiography.

RESULTS

Among 148 patients, SCM was diagnosed in 60 (46%) of them and had no relationship with median EA (SCM group: 0.73; no-SCM group: 0.66, p = 0.48). Recovery from SCM was observed in 24 patients (49%) and was independently associated with the PMX-HP (OR 4.19, 95%CI [1.22, 14.3]; p = 0.02) and the SAPS2 II score (OR 0.94, 95%CI [0.9, 0.98]; p = 0.006). In the SCM group, the 28-day mortality was 60% and was independently predicted by R-SCM (OR 0.02, 95%CI [0.001, 0.3] p = 0.005) and SAPS II score (OR 1.11, 95%CI [1.01, 1.23] p = 0.037).

CONCLUSIONS

In septic patients, EA was not associated with SCM. However, endotoxin removal by Polymyxin-B hemoperfusion was associated with recovery from cardiomyopathy, which was a predictor of lower 28-day mortality.

Effect of Fluorographene Addition on Mechanical and Adhesive Properties of a New Core Build-Up Composite

This study aims to develop a restorative material having such mechanical and adhesive properties that it can be used both as a reconstruction material and as a luting cement. The experimental core build-up composite (CBC) was derived from a self-adhesive cement by the modification of its chemical formula, requiring the use of dedicated dentin and ceramic primers. The adhesive properties to zirconia and dentin were analyzed with a micro-Shear Bond Strength test (mSBS). The mechanical properties were analyzed by a flexural strength test. The results were compared with those obtained for other commercially available cements and core build-up materials, both before and after addition of 2 wt.% fluorographene. The CBC obtained average values in the mSBS of 49.7 ± 4.74 MPa for zirconia and 32.2 ± 4.9 MPa for dentin, as well as values of 110.9 ± 9.3 MPa for flexural strength and 6170.8 ± 703.2 MPa for Young's modulus. The addition of fluorographene, while increasing the Young's modulus of the core build-up composite by 10%, did not improve the adhesive capabilities of the primers and cement on either zirconia or dentin. The CBC showed adhesive and mechanical properties adequate both for a restoration material and a luting cement. The addition of 2 wt.% fluorographene was shown to interfere with the polymerization reaction of the material, suggesting the need for further studies.

A case of fatal embolization during laser lithotripsy

PURPOSE

To report in literature the first case of fatal multi-organ embolization of ureteral stones fragments during laser lithotripsy.

CASE PRESENTATION

A tetraplegic 43-year-old woman was admitted to the hospital to undergo laser lithotripsy because of bilateral ureteral stones and right ureteral infected stent. During the removal of the right ureteral stent, the patient developed a sudden severe bradycardia followed by a reduction in the arterial oxygen saturation. In spite of a rapid and intensive medical intervention, the clinical picture did not improve; the woman was therefore transferred to the nearest Emergency Room where she was rescued but a cardiocirculatory arrest occurred. A claim of alleged medical malpractice was brought against the urologists. A complete autopsy was performed 8 days after death.

AUTOPSY FINDINGS

The diagnosis was determined by the microscopic findings: they have unequivocally shown a massive embolization of calculus fragments in the lungs and in the heart. In the light of all these findings, the cause of death was attributable to a disseminated intravascular coagulation due to this unforeseeable embolization of calcified amorphous material.

CONCLUSION

Embolization of calculus fragments represents an important challenge because it is extremely unpredictable. Indeed, a prompt diagnosis of non-thrombotic pulmonary embolism, during the urologic procedure, is extremely difficult because the condition presents with no specific clinical signs: this life-threatening pathology is often underestimated. For this reason, the autopsy and the subsequent histopathological examination are indispensable in order to prove lethal embolization: microscopic findings play a key role in the final diagnosis of death.

Ultrasound assessment of rectus femoris and anterior tibialis muscles in young trauma patients

Purpose

Quantitative and qualitative changes of skeletal muscle are typical and early findings in trauma patients, being possibly associated with functional impairment. Early assessment of muscle changes—as evaluated by muscle ultrasonography—could yield important information about patient’s outcome.

Methods

In this prospective observational study, we used ultrasonography to evaluate the morphological changes of rectus femoris (RF) and anterior tibialis (AT) muscles in a group of young, previously healthy trauma patients on enteral feeding.

Results

We studied 38 severely injured patients (median Injury Severity Score = 34; median age = 40 y.o.) over the course of the ICU stay up to 3 weeks after trauma. We found a progressive loss of muscle mass from day 0 to day 20, that was more relevant for the RF (45%) than for the AT (22%); this was accompanied by an increase in echogenicity (up to 2.5 by the Heckmatt Scale, where normal echogenicity = 1), which is an indicator of myofibers depletion.

Conclusions

Ultrasound evaluation of skeletal muscles is inexpensive, noninvasive, simple and easily repeatable. By this method, we were able to quantify the morphological changes of skeletal muscle in trauma patients. Further studies may rely on this technicque to evaluate the impact of different therapeutic strategies on muscle wasting.

Gold-silver alloy semi-nanoshell arrays for label-free plasmonic biosensors

Nanosphere lithography coupled with reactive ion etching has been used to synthesize hexagonal ordered arrays of Au-Ag bimetallic semi-nanoshells to be used as plasmonic biosensors. The degree of lateral interaction between adjacent semi-nanoshells can be controlled by tailoring the reactive ion etching time in order to boost the global plasmonic properties through the formation of near-field hot-spots, which in turn can improve the sensitivity of the biosensors. To test the efficiency of the proposed system as a biosensor, we used an established protocol for the detection of biomolecules (local sensitivity), based on the receptor-ligand approach and using the biotin-streptavidin model system. We also tested the sensitivity to a homogeneous change in the refractive index of the buffer over the sensor (bulk sensitivity). Comparing the obtained results to those of an array of nanoprisms, chosen as a benchmark, significantly higher performances both in local and bulk sensitivities have been found, in agreement with electrodynamics simulations based on finite-element methods.

Immunonutrients in critically ill patients: an analysis of the most recent literature

Modulation of inflammatory and immune response to critical illness has been the goal of much research in the last decade and a variety of drugs and nutrients (so called "immunonutrients") have been tested in experimental models with promising results. Though, in the clinical setting of intensive care, their efficacy have been inconsistently proven, most likely because the effects of each drug may vary in relation to the timing, the dose, the route of administration, the interaction with other nutrients, the severity of illness and many other factors. Though the early studies of the beginning of this century (2000-2009) have shown some clinical benefits, recent multicenter trials (2011-2015) have failed to prove a consistent benefit of immunonutrition in terms of mortality or other clinical endpoints. Reviewing the latest evidence-based documents on this subject (multicenter trials, systematic reviews, meta-analyses and international guidelines), there is no convincing evidence that immunonutrients may be beneficial in the critically ill. Considering that these substances invariably increase the costs of health care and may be unsafe or even harmful in some subgroups, particularly in septic patients, we conclude that routine administration of immune-nutrients (glutamine, arginine, omega-3 fatty acids, selenium, etc.) cannot be currently recommended in the critically ill.

In vivo fate of avidin-nucleic acid nanoassemblies as multifunctional diagnostic tools

This study describes the formulation optimization and body-cell distribution and clearance in mice of a dually fluorescent biodegradable poly avidin nanoassembly based on the novel Avidin-Nucleic-Acid-Nano-ASsembly (ANANAS) platform as a potential advancement of classic avidin/biotin-based targeted delivery. The nanoformulation circulates freely in the bloodstream; it is slowly captured by filter organs; it is efficiently cleared within 24-48 h, and it is poorly immunogenic. The system displays more favorable properties than its parent monomeric avidin and it is a promising tool for diagnostic purposes for future translational aims, for which free circulation in the bloodstream, safety, multifunctionality and high composition definition are all necessary requirements. In addition, the assembly shows a time-dependent cell penetration capability, suggesting it may also function as a NP-dependent drug delivery tool. The ease of preparation together with the possibility to fine-tune the surface composition makes it also an ideal candidate to understand if and how nanoparticle composition affects its localization.

Integrated architecture for the electrical detection of plasmonic resonances based on high electron mobility photo-transistors

We report the design of an integrated platform for on-chip electrical transduction of the surface plasmon resonance supported by a nanostructured metal grating. The latter is fabricated on the active area of a GaAs/AlGaAs photo-HEMT and simultaneously works as the electronic gate of the device. The gold plasmonic crystal has a V-groove profile and has been designed by numerical optical simulations. By showing that the numerical models accurately reproduce the phototransistors experimental response, we demonstrate that the proposed architecture is suitable for the development of a new class of compact and scalable SPR sensors.

Synthesis and chromatography-free purification of PNA-PEO conjugates for the functionalisation of gold sensors

Peptide Nucleic Acids (PNAs) linked to high molecular weight (MW) poly(ethylene oxide) (PEO) derivatives could be useful conjugates for the direct functionalisation of gold surfaces dedicated to Surface Plasmon Resonance (SPR)-based DNA sensing. However their use is hampered by the difficulty to obtain them through a convenient and economical route. In this work we compared three synthetic strategies to obtain PNA-high MW PEO conjugates composed of (a) a 15-mer PNA sequence as the probe complementary to genomic DNA of Mycobacterium tuberculosis, (b) a PEO moiety (2 or 5 KDa MW) and (c) a terminal trityl-protected thiol necessary (after acidic deprotection) for grafting to gold surfaces. The 15-mer PNA was obtained by solid-phase synthesis. Its amino terminal group was later condensed to bi-functional PEO derivatives (2 and 5 KDa MW) carrying a Trt-cysteine at one end and a carboxyl group at the other end. The reaction was carried out either in solution, using HATU or PyOxim as coupling agents, or through the solid-phase approach, with 49.6%, 100% and 5.2% yield, respectively. A differential solvent extraction strategy for product purification without the need for chromatography is described. The ability of the 5 KDa PEO conjugate to function as a probe for complementary DNA detection was demonstrated using a Grating-Coupling Surface Plasmon Resonance (GC-SPR) system. The optimized PEO conjugation and purification protocols are economical and simple enough to be reproduced also within laboratories that are not highly equipped for chemical synthesis.

BIODEGRADABLE BIOARTIFICIAL MATERIALS MADE BY CHITOSAN AND POLY(VINYL ALCOHOL). PART II: ENZYMATIC DEGRADABILITY AND DRUG-RELEASING ABILITY

Bioartificial biodegradable materials were prepared mixing chitosan (CHI) and poly(vinyl alcohol) (PVA), then manufactured as films, and finally cross-linked with glutaraldehyde (GTA), both in the absence and in the presence of the edible hexa-alcohol sorbitol (SOR), as a plasticizer. The release of the components into water was tested by high performance liquid chromatography (HPLC); no release of CHI and scarce release of PVA were found. The water uptake was tested by measuring the swelling of the materials, after incubating them for 20 h in an atmosphere saturated with water vapor at 37°C. The swelling percentage increases with increasing CHI content in the blends, although it is the less hydrophilic polymer. This behavior was attributed to the difficulty of water to diffuse through the crystalline PVA structure, which is partially altered in the blends. The addition of SOR enhances the water sorption, as expected. The biodegradability of the materials was tested using the specific enzyme chitosanase, and was found to depend on the blend composition, as well as to be enhanced by the addition of SOR. The initial degradation rates were calculated; the maximum rates were found when the CHI to PVA ratio was 80:20 for all systems. The results of the enzymatic degradation generally agree with those of the swelling. The cross-linked blends were also tested as drug-delivery systems. The drugs chosen were the vitamin L-ascorbic acid (AsA) and the anti-cancer drug paclitaxel (PTX). The effective diffusion coefficients, D eff , were evaluated for the release of both the drugs from each material. Those of AsA are greater, of many powers of ten, than those of PTX, owing mainly to the hydrophilic nature of the first drug and to the hydrophobic of the second one. In conclusion, these materials seem available for biomedical use.

NON CONVENTIONAL SURFACE FUNCTIONALIZATION OF POROUS POLY-ε-CAPROLACTONE SCAFFOLDS USING BIOACTIVE MOLECULARLY IMPRINTED NANOSPHERES

Polymeric scaffolds, in the form of porous membranes, modified to favour cell adhesion and proliferation on their surface, were prepared using an innovative technique of functionalization, based on molecularly imprinting technology.

A series of membranes based on poly-ε-caprolactone were obtained through phase inversion using different solvents and non-solvents. Diffusion tests showed that prepared membranes exhibited a good permeability towards important nutrients such as folic acid and glucose. The ability of membranes, modified with imprinted nanoparticles, to facilitate cell adhesion and proliferation was evaluated by cell culture method using murine fibroblast cell line. SEM analysis at 72 h after seeding revealed an improved cell distribution on the surface of the membranes functionalized by deposition of molecularly imprinted nanoparticles.

BIODEGRADABLE BIOARTIFICIAL MATERIALS MADE BY CHITOSAN AND POLY(VINYL ALCOHOL) PART III: MATERIALS TOUGHENED BY MEANS OF A DEHYDROTHERMAL TREATMENT

The bioartificial chitosan–poly(vinyl alcohol) blends were toughened by means of a dehydrothermal treatment (DHT), to facilitate the formation of hydrogen bonds between the macromolecules. The materials were characterized by stress–strain test, contact angle measurement, spotlight Fourier transform infrared spectroscopy and chemical imaging, weight loss in water, swelling in water vapor saturated atmosphere, Alamar blue test to evaluate the indirect cytotoxicity, and the diffusive permeation, through membranes made with the blends, of D(+)glucose, vitamin B12, and bovine serum albumin. The results were compared with those of the blends crosslinked by glutaraldehyde (GTA). The Young's modulus ranges between 10.56 and 16.12 MPa, and it is higher for the blends subjected to DHT than for those crosslinked by GTA, a fact explainable by the elasticity of the latter, due to the flexible bridges connecting the different chains. The contact angles indicate a scarce wettability, and then a scarce hydrophilicity, which is confirmed by the chemical imaging of the surfaces, made in the total reflection (microATR) mode, of the films toughened by DHT: the ν(OH) band in the 4000–3000 cm-1 is nearly absent in all the regions of the maps. Moreover, the correlation maps indicate a homogeneous distribution of the two components within the blends. The weight loss in water is generally less than 15%, and increases with the content of the ionizable macromolecule chitosan in the blends, a trend shown also by the swelling after exposure to water vapors. Alamar blue test shows that none of the eluates, after being in contact with the materials up to seven days, appears cytotoxic toward murine fibroblasts. As concerning the diffusive permeation, it appears good for D(+)glucose, quite good for vitamin B12, and scarce for bovine serum albumin. In conclusion, the chitosan–poly(vinyl alcohol) blends studied appear to be suitable for their use as biomaterials.

Molecularly imprinted bioartificial membranes for the selective recognition of biological molecules. Part 2: release of components and thermal analysis

Molecularly imprinted membranes imprinted for a large-molecular-weight protein were realised using a blend of natural and synthetic polymers. Bioartificial membranes of synthetic (poly(ethylene-co-vinyl alcohol)-EVAL, Clarene) and biological (Dextran) polymers, molecularly imprinted with alpha-amylase as the template, were prepared and investigated. Dimethyl sulfoxide (DMSO) solutions of the alpha-amylase template, Clarene and Dextran were mixed under stirring in the desired proportions and dipped in DMSO (solvent)/water (non solvent) mixture, to obtain the phase separation. The release of Clarene, Dextran and alpha-amylase in the inversion baths was quantified by spectrophotometric methods and final composition of membranes was established. To study the interactions between the polymer components and between polymeric materials and the template, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out. Results indicated that stable and continuous bioartificial membranes of Clarene and Dextran can be obtained, whereby calorimetric analysis suggested the presence of high interaction between alpha-amylase and the Clarene component.

Molecularly imprinted bioartificial membranes for the selective recognition of biological molecules

Membranes of a synthetic (poly(ethylene-co-vinyl alcohol), Clarene) and a biological (dextran) polymer, imprinted with alpha-amylase, of different compositions were prepared by the phase-inversion process. Membrane morphologies were shown to be dependent on the synthetic-biological components composition. The removal of the template from the membranes was performed by extraction with water, while an aqueous solution of alpha-amylase was permeated across the membranes under pressure to obtain the rebinding of the template. The selectivity of alpha-amylase-imprinted membranes was investigated by the same uptake experiment using pepsin, albumin and amyloglucosidase, and the rebinding of these proteins was compared with that of the print molecule. Before and after template extraction and after the rebinding experiment, kinetic measurements of the imprinting molecule were conducted to estimate the activity of the enzyme immobilised in the polymer matrix. Results obtained revealed that the immobilised enzyme maintains a good functionality while in the membrane compared to the free enzyme and the imprinted 'bioartificial' dextran and Clarene membranes, obtained by the phase-inversion method, can establish efficient interaction with alpha-amylase as template molecule, as confirmed by the fair selectivity in rebinding tests.

The relevance of the transfer of molecular information between natural and synthetic materials in the realisation of biomedical devices with enhanced properties

Past and recent attempts to introduce in synthetic polymers molecular information from natural substances through simple blending, template polymerization and molecular imprinting are reviewed. The most promising approaches that can open the way to the realisation of new materials with improved biocompatibility, antibody- or enzyme-like performances are analysed more deeply. The realisation of bioartificial blends from natural and synthetic polymers, molecularly imprinted nanospheres or membranes that can act as recognition element in (bio)sensing devices, as synthetic enzymes or as key constituents of body fluids purification tools is presented in order to make the reader aware of the fascinating possibilities that these techniques make available to the biomedical science and engineering in the close future. The last part of the paper describes recent attempts to insert recognition elements for large molecules as proteins, DNA segments, viruses or whole cells in synthetic polymer systems, in order to develop new systems in the treatments of diseases and for tissue-engineering applications.

Characterization of multifunctional nanosystems based on the avidin-nucleic acid interaction as signal enhancers in immuno-detection

The Avidin-Nucleic-Acids-Nano-Assembly (ANANAS) is a kind of soft poly avidin nanoparticle originating from the high affinity interaction between avidin and the nucleic acids. In this work we investigated the possibility of transforming ANANAS cores into stoichiometrically controlled multifunctional nanoparticles through a "one-pot" procedure, and we measured in a quantitative way their ability to work as reagents for enhanced immunodiagnostic detection. Initially, we measured the ANANAS loading capability for biotinylated proteins of different nature. About 200 molecules of biotin-horseradish-peroxidase (40KDa b-HRP) and 60 molecules of biotin-immunoglobulin-G (150KDa b-IgG) could be accommodated onto each nanoparticle, showing that steric limitations dictate the number of loadable entities. Stoichiometrically controlled functional assemblies were generated by mixing core particles with subsaturating amounts of b-HRP and b-IgG. When applied as detection reagents in an Enzyme-Linked-ImmunoSorbed-Assay (ELISA), these assemblies were up to two-orders of magnitude more sensitive than commercial HRP-based reagents. Assemblies of different composition displayed different efficacy, indicating that the system functionality can be fine-tuned. Within-assay variability (CV%), measured to assess if the assembly procedure is reproducible, was within 10%. Stability experiments demonstrated that the functionalyzed assemblies are stable in solution for more than one week. In principle, any biotinylated function can be loaded onto the core particle, whose high loading capacity and tunability may open the way toward further application in biomedicine.

Engineering membranes for molecular recognition

The technology of molecular imprinting permits recognition sites to be inserted into a polymeric material through the polymerisation of a monomer in the presence of a template, or through the dissolution of a preformed polymer in a solution containing the template and then crosslinking or phase inversion so as to obtain the matrix-template complex. This paper will focus on the application of both techniques in the realisation of polymeric membranes with molecular recognition properties in aqueous environments.

Combined drug release from biodegradable bilayer coating for endovascular stents

In this work, the characterization of a biodegradable bilayer system, used as controlled and combined drug delivery platform, is reported. For this aim, a bilayer system, composed of poly(lactic-co-glycolic acid) and poly(3-hydroxybutyric-co-3-hydroxyvaleric acid), was investigated under physicochemical and functional aspects by evaluating polymer/polymer and polymer/stent material interactions, the kinetic of in vitro degradation, and drug release properties, comparing results with the monolayer reference systems. Obtained results showed that the bilayer system allowed increasing the total amount of eluted Tacrolimus and Paclitaxel drugs with respect to the monolayer systems in the considered testing period and conditions. This evidence was associated to a faster degradation of the tested copolymers in the bilayered configuration, excluding a synergic effect of two drugs on delivery performance. In addition, a macromolecular relaxation process was identified to govern the PLX release from poly(lactic-co-glycolic acid), whereas a pure Fickian diffusion occurred in the delivery of Tacrolimus from poly(3-hydroxybutyric-co-3-hydroxyvaleric acid).

Long-term results of the Italian Association of Pediatric Hematology and Oncology (AIEOP) Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia

We analyzed the long-term outcome of 4865 patients treated in Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia (ALL) of the Italian Association of Pediatric Hematology and Oncology (AIEOP). Treatment was characterized by progressive intensification of systemic therapy and reduction of cranial radiotherapy. A progressive improvement of results with reduction of isolated central nervous system relapse rate was obtained. Ten-year event-free survival increased from 53% in Study 82 to 72% in Study 95, whereas survival improved from 64 to 82%. Since 1991, all patients were treated according to Berlin-Frankfurt-Muenster (BFM) ALL treatment strategy. In Study 91, reduced treatment intensity (25%) yielded inferior results, but intensification of maintenance with high-dose (HD)-L-asparaginase (randomized) allowed to compensate for this disadvantage; in high-risk patients (HR, 15%), substitution of intensive polychemotherapy blocks for conventional BFM backbone failed to improve results. A marked improvement of results was obtained in HR patients when conventional BFM therapy was intensified with three polychemotherapy blocks and double delayed intensification (Study 95). The introduction of minimal residual disease monitoring and evaluation of common randomized questions by AIEOP and BFM groups in the protocol AIEOP-BFM-ALL 2000 are expected to further ameliorate treatment of children with ALL.

Acrylic Copolymers as Candidates for Drug-Eluting Coating of Vascular Stents

The aim of the present work is the synthesis and characterization of polymer materials showing good adhesion, drug loading, and delivery properties, for potential cardiovascular application. In particular, poly(methylmethacrylate-co-acrylic acid) copolymers are prepared in different compositions by a radical polymerization and investigated as potential materials to coat metallic stents and to carry out a local drug release. Films obtained by dissolving the copolymer in an appropriate organic solvent (also loaded with an anti-restenosis drug, such as tacrolimus) are investigated: physicochemical properties, adhesiveness to metallic stent material, and kinetics of drug release in physiological environment are studied.

Composite membranes modified with recognition-able nanobeads as potential adsorbers for purification of biological fluids

Therapeutic approaches in the clinical field require advanced properties for delivery or recognition of clinical species. The molecular imprinting method allows selective cavities to be inserted into a polymeric material built ""around"" a stamp molecule (template) through polymerization or phase inversion. This study focuses on the application of both methods in the realization of polymeric membranes with selective recognition and adsorption properties. Imprinted polymethacrylic acid (PMAA) particles, exhibiting specific binding sites for cholesterol molecule (template), were realized via precipitation polymerization in the shape of nanobeads and loaded in the bulk or on the surface of methylmethacrylate-acrylic acid P(MMA-co-AA) membranes obtained by the non-solvent induced phase separation (NIPS) technique. In this way, specific cavities were introduced into the membrane network to enhance and specialize uptake performances of the porous membranes taking advantage of the particle characteristics. Rebinding performances towards cholesterol in a physiological environment were tested showing very interesting results: the adsorption of cholesterol molecules from physiological solution was increased by using composite membrane-nanobead systems instead of control membranes (a quantitative increase of 14 mg of cholesterol per g of polymer matrix in respect of blank membrane was detected). The results obtained showed an improved performance of composite membranes, but also an unmodified behavior of loaded nanobeads (with respect to free ones) concerning the recognition capability in aqueous medium, which is the most difficult obstacle to overcome in molecular imprinting. The absolute rebinding capacity and the imprinting efficiency of membranes were in the range (and in some case higher) of other efficient systems, but the real improvement was that molecularly imprinted embranes showed an excellent recognition capacity in physiological medium instead of organic solvents.

Poly(methyl methacrylate) membranes with controlled porosity for advanced multi-step drug elution

Most of the systems developed for controlled drug delivery applications depend on membrane technology and their preparation parameters. For some applications, a dense membrane structure used in controlled-release systems can excessively prolong drug release due to the low permeability of the coating to the drug or to the low solubility of the drug in water. In these cases, to increase the drug delivery rate, asymmetric membranes can be prepared by a phase-inversion technique, allowing a different drug delivery approach with respect to dense membranes. In this study, porous poly(methyl methacrylate) membranes with different vacuum degrees were prepared through the phase-inversion process. Ternary homogeneous solutions, obtained by mixing polymer, tetrahydrofuran (THF) and water in the desired amounts, were precipitated by the evaporation of a solvent (THF) and a non-solvent (water) at a controlled temperature and ventilation. Membrane morphology, investigated by scanning electron microscopy, showed it to have a diffuse porosity with a regular arrangement and geometry of pores on the top surface. The porosity degree of the membranes, mainly relying on the starting polymer concentration, was also investigated by the use of the software Image-Pro Plus, indicating the presence of a relationship between porosity and permeability characteristics. Membranes, containing folic acid as a model drug, were tested for their transport characteristics and drug delivery both in diffusive and in convective- diffusive conditions. Transport and release parameters, as well as permeability and effective diffusivity, were found to be dependent on the porosity and vacuum degree, which could be controlled by varying the preparation conditions. Furthermore, these membranes showed high hydraulic permeability and rapid drug release, suggesting their use for applications where an intensive therapy in the first few days is required, followed by a constant and slow release for a longer time (two-step drug delivery).

Enzymatic Erosion of Bioartificial Membranes to Control Drug Delivery

The preparation of an enzymatic controlled drug release system from blends of PVA/starch/alphaA, in the form of films, is described. It was shown that alphaA hydrolyses the starch within these films, resulting in a time-dependent change of the porosity in the matrix. Films were characterized by calorimetric analysis to study the interactions between the enzyme and the polymeric constituents at the molecular level. The presence of alphaA, in fact, influenced the PVA crystallization in the blends. Release tests and permeability experiments were carried out to evaluate the transport properties of the films. An increase in porosity and permeability was observed by increasing alphaA content (16-28 wt.-%). Films loaded with theophylline and caffeine were also prepared to analyze drug release properties of the matrix. Drug release kinetics were coherent with the measured changes in porosity: at higher alphaA concentrations the amount of released drug increased under the influence of diffusion and erosion processes. The results obtained are promising for the realization of drug delivery devices for a rapid release or for the release of poorly soluble drugs which usually remain entrapped in the matrix.SEM images of a PVA/starch/alphaA film before (A) and after (B) the erosion.

Supported imprinted nanospheres for the selective recognition of cholesterol

The preparation of innovative polymeric systems using molecular imprinting technology for application in extracorporeal blood purification is described. Membranes based on a methylmethacrylate-co-acrylic acid copolymer, produced through the phase inversion method, were modified introducing into their structure specific binding sites for cholesterol molecule by adding molecularly imprinted nanoparticles in the membrane matrix. Membranes prepared are intended to selectively remove cholesterol from the blood by using interactions at a molecular level, between the membrane/nanoparticles devices and the template, created during the preparation of polymers. Three polymeric systems in form of nanoparticles were prepared differing in the polymerisation solvent (a mixture of acetonitrile and ethanol (1:1) or pure ethanol), and the molar ratio between the functional monomer and the cross-linker (2.3:1 and 1:1). Two out of three of the prepared polymers showed a very good template rebinding capacity both in phosphate buffer solution (pH 6.9) and in ethanol. In particular the nanoparticles rebound 115.4 mg cholesterol/g polymer in buffer solution, and 57 mg cholesterol/g polymer in ethanol. The deposition of the nanoparticles on the surface of the phase inversion membranes produced devices with interesting rebinding performances towards cholesterol in buffer solution: a specific recognition of 14.09 mg cholesterol/g system (membrane and nanoparticles) was detected, indicating maintained binding capacity of supported particles as well.

Release of proteinic and non-proteinic compounds from novel ionizable hydrogels: Effect of pH on swelling and drug delivery behavior

Ionizable hydrogels were prepared from new copolymers, poly(vinylalcohol-co-acrylic acid) indicated as P(VA-co-AA), by freezing-thawing processes. These materials are designed as potential controlled delivery devices with specific properties to respond to chemical environment stimuli. The swelling behavior of the P(VA-co-AA) hydrogels was evaluated in response to pH changes in release medium demonstrating a strong dependence with the environmental pH. The release of theophylline (THO) and bovine serum albumin (BSA) incorporated into the hydrogels before freezing-thawing cycles were examined by varying the pH. The release curves of the two different solutes showed a very similar trend depending on the hydrogel porosity and the medium pH. The dependence of THO and BSA release on their size and ionic nature was detected.

Designing porous bioartificial membranes for clinical use with desired morphological and transport properties by phase inversion control

Bioartificial membranes of synthetic (poly(ethylene-co-vinyl alcohol) - EVAL, Clarene (R) ) and biological (dextran) polymers with different compositions were prepared through the phase inversion process. Dimethyl sulfoxide (DMSO) solutions of EVAL and dextran were mixed under stirring in the desired proportions and coagulated in water or DMSO (solvent)/water (non-solvent) mixture. Membrane morphologies were shown to be dependent on the synthetic and biological polymer contents and on the coagulation medium composition. Component release during solid membrane formation was evaluated by a UV method and the final composition of the bioartificial membranes established, confirming the successful entrapment of the biological component in the synthetic network. The porosity degree of the bioartificial membranes was also investigated by permeability tests and the effect of morphological characteristics on transport properties was studied. Water flux across the membranes, solute permeability and sieving coefficients were also calculated. The results revealed that the transport properties of these bioartificial membranes, obtained by the phase inversion method, could be controlled by mainly changing the preparation control parameters and the EVAL-dextran ratio.

Transport Properties of EVAl-Starch-α Amylase Membranes

We investigated the influence of various physicochemical parameters on the morphology and time-porosity formation of membranes composed of ethylene-vinyl alcohol, starch, and alpha-amylase. In particular, we determined that (1) it is possible to obtain a membrane with desired porosity by phase inversion in an appropriate water-ethanol mixture and (2) the enzymatic bioerosion is controlled by the amount of alpha-amylase present in the blend. Although no experiments involving drugs were carried out, the delivery properties of the film were determined by measuring the Darcy permeability, the effective diffusivity, and the mean reaction rate of the membranes, relating them to the modality of membrane preparation, the amount of enzyme present within the membrane, and the incubation time of the samples in a buffer solution. Simple theoretical models of the delivery properties of the membranes were developed, leading to predictions that were in good agreement with the experimental results.

Acrylic polymeric nanospheres for the release and recognition of molecules of clinical interest

Cross-linked poly(methylmethacrylate-co-methacrylic acid) nanospheres were imprinted with theophylline through template radical polymerisation in diluted acetonitrile solution. This study will focus on the effect of functional monomer nature used (methylmethacrylate and/or methacrylic acid) in the recognition and in the release of template in order to develop a material with combined properties of drug delivery and rebinding for clinical applications. After template extraction the nanospheres showed satisfactory recognition properties (up to 1mg template/g of polymer). Moreover polymers prepared selectively removed theophylline with a theophylline rebinding of 5.1 times higher than that of caffeine, a compound of similar structure. Drug release properties were also satisfactory (up to 95% of loaded theophylline in 7 days).

Transplant-related toxicity and mortality: an AIEOP prospective study in 636 pediatric patients transplanted for acute leukemia

Hematopoietic stem cell transplantation can cure high-risk acute leukemia (AL), but the occurrence of non-leukemic death is still high. The AIEOP conducted a prospective study in order to assess incidence and relationships of early toxicity and transplant-related mortality (TRM) in a pediatric population. Between 1990 and 1997 toxicities reported in eight organs (central nervous system, heart, lungs, liver, gut, kidneys, bladder, mucosa) were classified into three grades (mild, moderate, severe) and prospectively registered for 636 consecutive children who underwent autologous (216) or allogeneic (420) transplantation, either from an HLA compatible related (294), or alternative (126) donor in 13 AIEOP transplant centers. Overall, 47% of the patients are alive in CR (3-year EFS: 45.2%, s.e.: 2.1), 19% died in CR at a median of 60 days (90-day TRM: 14.3%, s.e.: 1.4), 34% relapsed. Toxicity of any organ, but mucosa and gut, was positively correlated with early death; moderate and severe toxicity to heart, lungs, liver and kidneys significantly increased early TRM, with estimated relative risks of 9.1, 5.5, 2.7 and 2.8, respectively, as compared to absent or mild toxicity. Patients with grade III-IV aGVHD experienced more than double (56% vs. 19%) TRM than patients with grade 0-II aGVHD. A higher cumulative toxicity score, estimating the impact of toxicity on TRM, was significantly associated with transplantation from an alternative donor. Quantitative assessment allowed us to describe the extent to which 'grade' of toxicity and 'type' of involved organs were related to mortality and pre-transplant characteristics and yielded a prognostic score potentially useful to compare different conditioning regimens and predict probability of early death.

Early and late deaths after elective end of therapies for childhood cancer in Italy

The first cohort of subjects treated for cancer during childhood is now entering adulthood, and it is necessary to determine whether treatment has been sufficient to completely eradicate the neoplastic clone, and whether the cancer itself or treatment-related toxicity may have increased the risk of premature death. For these reasons, long-term survival and causes of death were evaluated in a cohort of subjects treated for childhood cancer who reached the elective end of therapy in continuous remission and were registered until 1992 in the Italian Registry of off-therapy subjects (OTR). The vital status of OTR subjects was ascertained in 1996 by a postal survey through census bureaux; for deceased subjects, the cause of death was defined and compared with the expected rates in the general population. At follow-up, out of 6402 eligible and evaluable subjects, 890 were found to have died; the estimated overall survival at 20 years was 80.7% (95% CI 79.3-82.1). Most of the patients (84.6%) died due to recurrence of the primary cancer, usually within the first 5 years after the OT. The cumulative incidence of death due to recurrence of the primary tumor was greater among subjects treated for solid tumor than among those treated for leukemia/lymphoma (p = 0.0001); in contrast, OT subjects after leukemia and lymphoma were more likely to die due to of medical complications of therapy (p < 0.02). Second cancers were the second most frequent cause of death, with a 12-fold risk compared with the general population; the figures were similar in the 2 cancer groups. Compared with the general population, OT subjects were 32 times more likely than same-age subjects to die. The SMR decreased to 6.1 when only non-cancer deaths were considered. Deaths due to external or avoidable causes occurred among survivors at a rate similar to that of the general population.

Pelvic and paraortic lymph nodal status in advanced ovarian cancer and survival

BACKGROUND

In order to analyze the prognostic role of node involvement in advanced ovarian cancer, we have analyzed data from a randomized clinical trial on advanced ovarian cancer.

METHODS

Cases were 456 women who entered a randomized multicentric clinical trial comparing two cisplatin-based schemes of treatment after cytoreductive surgery for advanced stage III-IV ovarian cancer. They underwent selective pelvic and/or paraortic lymphadenectomy.

RESULTS

A total of 161 (35.3%) cases had positive nodes. The frequency of positive nodes was statistically significantly higher in FIGO stage IV than in stage III. Also grade 3 tumors were more likely to have positive nodes than grade 1-2 tumors. No association was observed between nodal status and response to chemotherapy. The 3-year survival was 46.2 (standard error (SE) = 3.4 based on 147 deaths) and 44.6 (SE = 4.4, based on 84 deaths), respectively, in negative and positive node groups. The corresponding values, when the analysis was performed considering only subjects with residual tumor <1 cm or absent, after first-line cytoreductive surgery were 66.2 (SE = 5.7) and 62.4 (SE = 9.6).

CONCLUSIONS

We did not find any association between nodal status and survival. Particularly, nodal status was not a prognostic factor for survival in the subgroup of women with residual tumor <1 cm or absent after cytoreductive surgery.

Intensive BFM chemotherapy for childhood ALL: interim analysis of the AIEOP-ALL 91 study. Associazione Italiana Ematologia Oncologia Pediatrica

BACKGROUND AND OBJECTIVE

Since 1988 the AIEOP has used BFM-based chemotherapy for childhood ALL. Current organization and results and role of cranial irradiation in the AIEOP-ALL 91 study are reported.

DESIGN AND METHODS

From 1991 to 1995, 1194 children (< 15 years) with non-B ALL, were enrolled and assigned to the standard risk [SR: age > 1 year, non-T-ALL, BFM risk factor (RF) < 0.8], intermediate risk (IR: RF > or = 0.8 but < 1.7, or with RF < 0.8 and age < 1 year, or T-ALL), or high risk [HR: RF > or = 1.7, or t(9;22), or t(4;11) or prednisone poor response or late response or CNS involvement] groups. All patients received initially protocol Ia. Thereafter SR patients received HD-MTX 2 g/m2, a modified protocol II, and continuation therapy with triple intrathecal chemotherapy (TIT); IR patients received protocol Ib, HD-MTX 5 g/m2, protocol II and continuation therapy with TIT; HR patients received 9 polychemotherapy blocks, cranial irradiation and continuation therapy. Duration of treatment was 24 months. A randomized study was conducted to evaluate the impact of high-dose asparaginase in non high risk patients: the results of this study cannot be disclosed yet.

RESULTS

One thousand one hundred and fifty-two (96.5%) patients achieved CR. Overall EFS (SE) at 5-years was 71.0% (1.4), with a survival of 80.3% (1.3). Relapse occurred in 262 children (21.9%), either in the marrow (n = 192 isolated and 32 with other sites, 18.7%), in the CNS (n = 18, 1.5%), or elsewhere (n = 20, 1.7%). 5-year EFS (SE) was 83.3% (2.4) in SR, 74.7% (1.8) in IR, and 39.7% (3.5) in HR groups, respectively.

INTERPRETATION AND CONCLUSIONS

Overall cure rate was higher than in the previous AIEOP-ALL 88 study. Treatment intensification with polychemotherapy blocks did not improve results in HR. Cranial irradiation can be safely omitted in over 80% of children treated with BFM based chemotherapy.