Nephroprotective effect of exercise training in cisplatin-induced renal damage in mice: influence of training protocol.

Cisplatin is an effective antineoplastic agent, but its use is limited by its nephrotoxicity caused by the oxidative stress in tubular epithelium of nephrons. On the other hand, regular exercise provides beneficial adaptations in different tissues and organs. As with many drugs, dosing is extremely important to get the beneficial effects of exercise. Thus, we aimed to investigate the influence of exercise intensity and frequency on cisplatin-induced (20 mg/kg) renal damage in mice. Forty male Swiss mice were divided into five experimental groups (n=8 per group): 1) sedentary; 2) low-intensity forced swimming, three times per week; 3) high-intensity forced swimming, three times per week; 4) low-intensity forced swimming, five times per week; and 5) high-intensity forced swimming, five times per week. Body composition, renal structure, functional indicators (plasma urea), lipid peroxidation, antioxidant enzyme activity, expression of genes related to antioxidant defense, and inflammatory and apoptotic pathways were evaluated. Comparisons considered exercise intensity and frequency. High lipid peroxidation was observed in the sedentary group compared with trained mice, regardless of exercise intensity and frequency. Groups that trained three times per week showed more benefits, as reduced tubular necrosis, plasma urea, expression of CASP3 and Rela (NFkB subunit-p65) genes, and increased total glutathione peroxidase activity. No significant difference in Nfe2l2 (Nrf2) gene expression was observed between groups. Eight weeks of regular exercise training promoted nephroprotection against cisplatin-mediated oxidative injury. Exercise frequency was critical for nephroprotection.

Nephroprotective effect of exercise training in cisplatin-induced renal damage in mice: influence of training protocol

Cisplatin is an effective antineoplastic agent, but its use is limited by its nephrotoxicity caused by the oxidative stress in tubular epithelium of nephrons. On the other hand, regular exercise provides beneficial adaptations in different tissues and organs. As with many drugs, dosing is extremely important to get the beneficial effects of exercise. Thus, we aimed to investigate the influence of exercise intensity and frequency on cisplatin-induced (20 mg/kg) renal damage in mice. Forty male Swiss mice were divided into five experimental groups (n=8 per group): 1) sedentary; 2) low-intensity forced swimming, three times per week; 3) high-intensity forced swimming, three times per week; 4) low-intensity forced swimming, five times per week; and 5) high-intensity forced swimming, five times per week. Body composition, renal structure, functional indicators (plasma urea), lipid peroxidation, antioxidant enzyme activity, expression of genes related to antioxidant defense, and inflammatory and apoptotic pathways were evaluated. Comparisons considered exercise intensity and frequency. High lipid peroxidation was observed in the sedentary group compared with trained mice, regardless of exercise intensity and frequency. Groups that trained three times per week showed more benefits, as reduced tubular necrosis, plasma urea, expression of CASP3 and Rela (NFkB subunit-p65) genes, and increased total glutathione peroxidase activity. No significant difference in Nfe2l2 (Nrf2) gene expression was observed between groups. Eight weeks of regular exercise training promoted nephroprotection against cisplatin-mediated oxidative injury. Exercise frequency was critical for nephroprotection.

Oxígeno hiperbárico para la cistitis inducida por radioterapia: un seguimiento a largo plazo / Hyperbaric oxygen for radiation-induced cystitis: A long-term follow-up

INTRODUCCIÓN Y OBJETIVOS: Alrededor del 12% de los pacientes tratados con radioterapia pélvica desarrollan complicaciones en la vejiga. La terapia de oxígeno hiperbárico (TOHB) es una opción para el manejo de la cistitis hemorrágica inducida por radioterapia (CHIR). El objetivo de este estudio fue evaluar la eficacia de la TOHB para tratar la cistitis por radioterapia e identificar factores predictivos para un resultado exitoso. MATERIAL Y MÉTODOS: Revisamos retrospectivamente a 105 pacientes diagnosticados de CHIR que recibieron un tratamiento de TOHB entre 2007 y 2016 en nuestro centro. Los pacientes recibieron oxígeno al 100% en una cámara hiperbárica multiplaza a 2,4 ATA durante 80 min. Todos los pacientes cumplimentaron un cuestionario en el que se documentaba la gravedad de los síntomas previos a la TOHB y tras el período de seguimiento. RESULTADOS: Después de una media de 40 sesiones de TOHB, hubo una tasa de éxito del 92,4% en el control de la hematuria. Durante el período de seguimiento (mediana de 63 meses), el 24,7% de los pacientes presentaron recurrencia de la hematuria. La puntuación media de las variables evaluadas en el cuestionario -disuria, frecuencia urinaria y hematuria- fue significativamente menor después del período de seguimiento (p <0,05). Nuestros datos muestran que cuanto antes se administre la TOHB después del primer episodio de hematuria, se logran mejores tasas de respuesta y se registran menores recurrencias en relación con la hematuria (p <0,05). No se observaron complicaciones graves. CONCLUSIONES: Nuestros resultados apoyan la seguridad y los beneficios a largo plazo de la TOHB para la CHIR y otros síntomas molestos de la vejiga, lo que supondría una mejora en la calidad de vida de nuestros pacientes

INTRODUCTION AND OBJECTIVES: Bladder complications may be seen in up to 12% of patients treated with pelvic irradiation. Hyperbaric oxygen therapy (HBOT) is an option for the management of radiation-induced hemorrhagic cystitis (RIHC). The aim of this study was to evaluate the efficacy of HBOT in radiation cystitis and to identify the predictive factors for a successful outcome. MATERIAL AND METHODS: We retrospectively reviewed 105 patients diagnosed with RIHC which were treated with HBOT between 2007 and 2016 in our institution. Patients received 100% oxygen in a multiplace hyperbaric chamber at 2.4atm for 80minutes. All patients fulfilled a questionnaire documenting symptom severity pre-HBOT and at the end of the follow-up period. RESULTS: After a median of 40 HBOT sessions, there was success rate of 92,4% in the control of hematuria. During our follow-up period (median of 63 months) 24,7% patients presented with recurrence of hematuria. The mean score of the questionnaire-assessed variables: dysuria, urinary frequency and hematuria, was significantly lower after the follow-up period (P<.05). Our data shows that the sooner HBOT is delivered after the first episode of hematuria, better response rates are achieved and lower recurrences concerning hematuria were registered (P<.05). No serious complications were observed. CONCLUSIONS: Our results support the safety and long-term benefits of HBOT on RIHC and other distressful bladder symptoms, which represents an expected improvement of quality of life in our patients

Hyperbaric oxygen for radiation-induced cystitis: A long-term follow-up. / Oxígeno hiperbárico para la cistitis inducida por radioterapia: un seguimiento a largo plazo.

INTRODUCTION AND OBJECTIVES: Bladder complications may be seen in up to 12% of patients treated with pelvic irradiation. Hyperbaric oxygen therapy (HBOT) is an option for the management of radiation-induced hemorrhagic cystitis (RIHC). The aim of this study was to evaluate the efficacy of HBOT in radiation cystitis and to identify the predictive factors for a successful outcome. MATERIAL AND METHODS: We retrospectively reviewed 105 patients diagnosed with RIHC which were treated with HBOT between 2007 and 2016 in our institution. Patients received 100% oxygen in a multiplace hyperbaric chamber at 2.4atm for 80minutes. All patients fulfilled a questionnaire documenting symptom severity pre-HBOT and at the end of the follow-up period. RESULTS: After a median of 40 HBOT sessions, there was success rate of 92,4% in the control of hematuria. During our follow-up period (median of 63 months) 24,7% patients presented with recurrence of hematuria. The mean score of the questionnaire-assessed variables: dysuria, urinary frequency and hematuria, was significantly lower after the follow-up period (P<.05). Our data shows that the sooner HBOT is delivered after the first episode of hematuria, better response rates are achieved and lower recurrences concerning hematuria were registered (P<.05). No serious complications were observed. CONCLUSIONS: Our results support the safety and long-term benefits of HBOT on RIHC and other distressful bladder symptoms, which represents an expected improvement of quality of life in our patients.

Presence of parasite DNA in clinically unaffected nasal mucosa during cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis.

OBJECTIVES: We aimed to detect Leishmania DNA carriage in nasal mucosa of individuals with cutaneous leishmaniasis (CL) caused by Leishmania (Viannia) braziliensis. METHODS: A cross-sectional study was performed in all individuals with CL without nasal lesions (n = 153) attended within 2 years in an endemic area of L. (Viannia) braziliensis in Bahia (Brazil). An otorhinolaryngologist assessed the clinical status of the nasal mucosa by anterior rhinoscopy and endoscopic examinations. Swab samples were collected for parasite DNA detection by PCR from all individuals before standard treatment for leishmaniasis. A second evaluation 3 months after treatment was performed to assess clinical outcomes. RESULTS: Parasite DNA was detected in 7.8% (12/153) of clinically healthy nasal mucosa of individuals with CL. Interestingly, DNA was more frequently identified in individuals with more skin lesions (median 1.5, interquartile range (IQR) 1-3.5 versus 1.0, IQR 1-1.5; p 0.044), or larger injuries (median 2.7, IQR 2-3.8 versus 1.6, IQR 1-2.5; p 0.013). Additionally, the disease of those individuals with positive PCR evolved more frequently to unusual forms of leishmaniasis (recidiva cutis and disseminated) (45.5% (5/11) versus 11.5% (14/122); p 0.009), and required more cycles of treatment to reach clinical cure (median 2, IQR 1-4 versus 1, IQR 1-2; p 0.05). CONCLUSION: These findings suggest an early parasite tropism to nasal mucosa in L. (Viannia) braziliensis infection and a clinical phenotype of CL cases associated with parasite DNA in nasal mucosa. Future studies should evaluate whether PCR of nasal swab samples could serve as a prognostic tool for individuals at risk of mucocutaneous leishmaniasis.

Controlled release of moxifloxacin from intraocular lenses modified by Ar plasma-assisted grafting with AMPS or SBMA: An in vitro study.

Intraocular lenses (IOLs) present an alternative for extended, local drug delivery in the prevention of post-operative acute endophthalmitis. In the present work, we modified the surface of a hydrophilic acrylic material, used for manufacturing of IOLs, through plasma-assisted grafting copolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) or [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), with the aim of achieving a controlled and effective drug release. The material was loaded with moxifloxacin (MFX), a commonly used antibiotic for endophthalmitis prevention. The characterization of the modified material showed that relevant properties, like swelling capacity, wettability, refractive index and transmittance, were not affected by the surface modification. Concerning the drug release profiles, the most promising result was obtained when AMPS grafting was done in the presence of MFX. This modification led to a higher amount of drug being released for a longer period of time, which is a requirement for the prevention of endophthalmitis. The material was found to be non-cytotoxic for rabbit corneal endothelial cells. In a second step, prototype IOLs were modified with AMPS and loaded with MFX as previously and, after sterilization and storage (30days), they were tested under dynamic conditions, in a microfluidic cell with volume and renovation rate similar to the eye aqueous humour. MFX solutions collected in this assay were tested against Staphylococcus aureus and Staphylococcus epidermidis and the released antibiotic proved to be effective against both bacteria until the 12th day of release.

Listening to doctors on patients' use of healthcare during the crisis: uncovering a different picture and drawing lessons from Portugal.

Background: The consequences of financial crises on patients' use of healthcare have been widely discussed. This paper seeks to ascertain whether the position of key players, i.e. doctors, may reveal realities other than those officially reported about the 2008 financial crisis. Methods: In 2013-14, a national survey of doctors was conducted in Portugal, which received international assistance in the wake of the financial crisis. An exploratory model comprising descriptive statistics, regression and independence analyses focused on doctors' experience of patients' use of medications, consultations, exams and treatment services, and whether they stopped treatments. Results: According to doctors, an unspecified number of patients experienced difficulties using healthcare as more patients requested prescriptions for cheaper medications or simply stopped treatments. Significant variations were found according to speciality, years of practice and sector of activity. Conclusions: Cost-containment mechanisms are regarded as necessary. However, the evidence indicated a side effect, i.e. a decrease in patients' ability to use healthcare, including in the National Health Service (NHS). It also highlighted the need to listen to health professionals as key informants on patient's behaviour and the daily functioning of health services.

Thickness-dependent electrocaloric effect in mixed-phase Pb0.87Ba0.1 La0.02(Zr0.6Sn0.33Ti0.07)O3 thin films.

Full-perovskite Pb0.87Ba0.1La0.02(Zr0.6Sn0.33Ti0.07)O3 (PBLZST) thin films were fabricated by a sol-gel method. These revealed both rhombohedral and tetragonal phases, as opposed to the full-tetragonal phase previously reported in ceramics. The fractions of tetragonal and rhombohedral phases are found to be strongly dependent on film thickness. The fraction of tetragonal grains increases with increasing film thickness, as the substrate constraint throughout the film decreases with film thickness. The maximum of the dielectric constant (εm) and the corresponding temperature (Tm) are thickness-dependent and dictated by the fraction of rhombohedral and tetragonal phase, with εm reaching a minimum at 400 nm and Tm shifting to higher temperature with increasing thickness. With the thickness increase, the breakdown field decreases, but field-induced antiferroelectric-ferroelectric (EAFE-FE) and ferroelectric-antiferroelectric (EFE-AFE) switch fields increase. The electrocaloric effect increases with increasing film thickness.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.

Development of UV cross-linked gelatin coated electrospun poly(caprolactone) fibrous scaffolds for tissue engineering.

Cardiovascular disease is the leading cause of morbidity and mortality among industrialized countries. Vascular grafts are often required for the surgical treatments. Considering the limitations associated with the use of autografts and with the currently available synthetic materials, a growing demand in tissue engineered vascular grafts has been registered. During the work here described, electrospinning technique was used to prepared fibrous matrices to be applied as vascular implants. For that purpose, electrospun polycaprolactone (PCL) fibrous mats were produced and afterwards coated with different hydrogel formulations based in photocrosslinkable gelatin (GelMA) and the macromers poly(ethylene glycol) acrylate (PEGA) and poly(ethylene glycol) diacrylate (PEGDA). These were further photocrosslinked under UV irradiation using Irgacure® 2959 (by BASF) as the photoinitiator. The suitability of the coated scaffolds for the intended application, was evaluated by assessing their chemical/physical properties as well as their interaction with blood and endothelial cells.

Hybrid management, organizational configuration, and medical professionalism: evidence from the establishment of a clinical directorate in Portugal.

BACKGROUND: The need of improving the governance of healthcare services has brought health professionals into management positions. However, both the processes and outcomes of this policy change highlight differences among the European countries. This article provides in-depth evidence that neither quantitative data nor cross-country comparisons have been able to provide regarding the influence of hybrids in the functioning of hospital organizations and impact on clinicians' autonomy and exposure to hybridization. METHODS: The study was designed to witness the process of institutional change from the inside and while that process was underway. It reports a case study carried out in a public hospital in Portugal when the establishment of a clinical directorate was being negotiated. Data collection comprises semi-structured interviews with general managers and surgeons complemented with observations. RESULTS: The clinical directorate under study illustrates a divisionalized professional bureaucracy model that combines features of professional bureaucracies and divisionalized forms. The hybrid manager is key to understand the extent to which practising clinicians are more accountable and to whom given that managerial tools of control have not been strengthened, and trust-based relations allow them to keep professional autonomy untouched. In sum, clinicians are allowed to profit from their activity and to perform autonomously from the hospital's board of directors. The advantageous conditions enjoyed by the clinical directorate intensify internal re-stratification in medicine, thus suggesting forms of divisionalized medical professionalism grounded in organizational dynamics. CONCLUSION: It is discussed the extent to which policy change to the governance of health organizations regarding the relationship between medicine and management is subject to specific constraints at the workplace level, thus conditioning the expected outcomes of policy setting. The study also highlights the role of hybrid managers in determining the extent to which practising professionals are more accountable to managerial criteria. The overall conclusion is that although medical and managerial values link to each other, clinicians reconfigure managerial criteria according to specific interests. Ultimately, medical autonomy and authority may be reinforced in organizational settings subject to NPM-driven reforms.

Production of new 3D scaffolds for bone tissue regeneration by rapid prototyping.

The incidence of bone disorders, whether due to trauma or pathology, has been trending upward with the aging of the worldwide population. The currently available treatments for bone injuries are rather limited, involving mainly bone grafts and implants. A particularly promising approach for bone regeneration uses rapid prototyping (RP) technologies to produce 3D scaffolds with highly controlled structure and orientation, based on computer-aided design models or medical data. Herein, tricalcium phosphate (TCP)/alginate scaffolds were produced using RP and subsequently their physicochemical, mechanical and biological properties were characterized. The results showed that 60/40 of TCP and alginate formulation was able to match the compression and present a similar Young modulus to that of trabecular bone while presenting an adequate biocompatibility. Moreover, the biomineralization ability, roughness and macro and microporosity of scaffolds allowed cell anchoring and proliferation at their surface, as well as cell migration to its interior, processes that are fundamental for osteointegration and bone regeneration.

Photocurable bioadhesive based on lactic acid.

Novel photocurable and low molecular weight oligomers based on l-lactic acid with proven interest to be used as bioadhesive were successfully manufactured. Preparation of lactic acid oligomers with methacrylic end functionalizations was carried out in the absence of catalyst or solvents by self-esterification in two reaction steps: telechelic lactic acid oligomerization with OH end groups and further functionalization with methacrylic anhydride. The final adhesive composition was achieved by the addition of a reported biocompatible photoinitiator (Irgacure® 2959). Preliminary in vitro biodegradability was investigated by hydrolytic degradation in PBS (pH=7.4) at 37 °C. The adhesion performance was evaluated using glued aminated substrates (gelatine pieces) subjected to pull-to-break test. Surface energy measured by contact angles is lower than the reported values of the skin and blood. The absence of cytoxicity was evaluated using human fibroblasts. A notable antimicrobial behaviour was observed using two bacterial models (Staphylococcus aureus and Escherichia coli). The cured material exhibited a strong thrombogenic character when placed in contact with blood, which can be predicted as a haemostatic effect for bleeding control. This novel material was subjected to an extensive characterization showing great potential for bioadhesive or other biomedical applications where biodegradable and biocompatible photocurable materials are required.

Production and characterization of chitosan/gelatin/ß-TCP scaffolds for improved bone tissue regeneration.

Recently, bone tissue engineering emerged as a viable therapeutic alternative, comprising bone implants and new personalized scaffolds to be used in bone replacement and regeneration. In this study, biocompatible scaffolds were produced by freeze-drying, using different formulations (chitosan, chitosan/gelatin, chitosan/ß-TCP and chitosan/gelatin/ß-TCP) to be used as temporary templates during bone tissue regeneration. Sample characterization was performed through attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray diffraction and energy dispersive spectroscopy analysis. Mechanical characterization and porosity analysis were performed through uniaxial compression test and liquid displacement method, respectively. In vitro studies were also done to evaluate the biomineralization activity and the cytotoxic profile of the scaffolds. Scanning electron and confocal microscopy analysis were used to study cell adhesion and proliferation at the scaffold surface and within their structure. Moreover, the antibacterial activity of the scaffolds was also evaluated through the agar diffusion method. Overall, the results obtained revealed that the produced scaffolds are bioactive and biocompatible, allow cell internalization and show antimicrobial activity against Staphylococcus aureus. Such, make these 3D structures as potential candidates for being used on the bone tissue regeneration, since they promote cell adhesion and proliferation and also prevent biofilm development at their surfaces, which is usually the main cause of implant failure.

Osteopontin, CCL5 and CXCL9 are independently associated with psoriasis, regardless of the presence of obesity.

Psoriasis is an autoimmune disease associated with the production of pro-inflammatory cytokines. The identification of these molecules in the pathogenesis of psoriasis facilitated the use of monoclonal antibodies to block their actions as a treatment for severe psoriasis. An increased inflammatory response has been documented in patients with obesity, a condition that is associated with the occurrence and severity of psoriasis. Osteopontin (OPN), TNF and CXCL9 levels are enhanced in patients with psoriasis, although OPN has been documented in the adipose tissue of obese patients without psoriasis. The prevalence of obesity is much higher in psoriasis patients compared with the general population. Thus, we aimed to evaluate the relationship between cytokine levels and psoriasis in the context of obesity. We compared OPN and CXCL9 plasma levels among 117 psoriasis patients and 27 healthy body mass index-matched subjects using ELISA. We also analyzed the TNF, CCL2 and CCL5 levels in a smaller subgroup of patients and matched controls. Median OPN, CCL5 and CXCL9 levels were significantly higher in psoriasis patients compared with the controls, independent of obesity. There was no difference between the median CCL2 levels in the psoriasis patients and the controls (P<0.05), although the CCL2 levels were elevated in obese patients compared with non-obese psoriasis patients (P<0.001). Facial involvement and the psoriasis area severity index (PASI) score were not associated (P<0.05) with OPN levels or elevated levels of chemokines. There was no significant correlation between the OPN and CXCL9 levels or the OPN and TNF levels in psoriasis patients. This work confirms that OPN, CCL5 and CXCL9 plasma levels are higher in psoriasis patients and provides evidence that their higher levels are not a consequence of obesity. Furthermore, the results demonstrate that OPN production is independent of TNF-α and CXCL9.

New drug-eluting lenses to be applied as bandages after keratoprosthesis implantation.

Corneal tissue is the most commonly transplanted tissue worldwide. This work aimed to develop a new drug-eluting contact lens that may be used as a bandage after keratoprosthesis. During this work, films were produced using poly(vinyl alcohol) (PVA) and chitosan (CS) crosslinked with glyoxal (GL). Vancomycin chlorhydrate (VA) was impregnated in these systems by soaking. Attenuated total reflectance - Fourier transform infrared spectroscopy was used to confirm crosslinking. The cytotoxic and drug release profile, hydrophilicity, thermal and biodegradation as well as swelling capacity of the samples were assessed through in vitro studies. PVA and PVA/CS films were obtained by crosslinking with GL. The films were transparent, flexible with smooth surfaces, hydrophilic and able to load and release vancomycin for more than 8h. Biodegradation in artificial lachrymal fluid (ALF) with lysozyme at 37°C showed that mass loss was higher for the samples containing CS. Also, the samples prepared with CS showed the formation of pores which were visualized by SEM. All samples revealed a biocompatible character after 24h in contact with cornea endothelial cells. As a general conclusion it was possible to determine that the 70PVA/30CS film showed to combine the necessary features to prepare vancomycin-eluting contact lenses to prevent inflammation after corneal substitution.

Effect of blood in the cerebrospinal fluid on the accuracy of cerebral oxygenation measured by near infrared spectroscopy.

Near infrared spectroscopy (NIRS) is an optical technique used to examine the oxygenation state of tissues such as the brain in patients, including those with brain injury. We have examined the effect of a cerebrospinal fluid (CSF) contaminant, specifically haemoglobin, on the sensitivity of cerebral NIRS signals through computer simulation. Previous models of light transport in the head have shown that the clear CSF layer has a profound effect on the sensitivity profile of the NIRS signal due to its low absorbing, low scattering qualities. In subarachnoid haemorrhage, which may accompany brain injury, the principal near infrared chromophore, haemoglobin, is released into the CSF. Sensitivity was measured through forward modeling and the presence of haemoglobin within the CSF was modeled by increasing the absorption coefficient of the layer, with sensitivity quantified in terms of the partial pathlength of light within the brain. The model demonstrated that increases in the CSF absorption led to a marked decrease in the sensitivity to changes in the brain layer. This suggests that blood or other contaminants in the CSF may have a significant effect on the utility of NIRS for measurement of cerebral oxygenation, and merits further investigation.

Occupational airborne contact dermatitis caused by usnic acid in a domestic worker

No disponible

Surface modification of polyurethane films by plasma and ultraviolet light to improve haemocompatibility for artificial heart valves.

Prosthetic cardiac valves implantation is a common procedure used to treat heart valve diseases. Although there are different prostheses already available in the market (either mechanical or bioprosthetic), their use presents several problems, specifically concerning thrombogenicity and structural failure. Recently, some progresses have been achieved in developing heart valves based on synthetic materials with special emphasis in polymers. Among them, polyurethanes are one of the most commonly used for the production of these devices. Herein, Elastollan(®)1180A50, a thermoplastic polyurethane (TPU), was used to formulate films whose surfaces were modified by grafting 2-hydroxyethylmethacrylate (HEMA) either by ultra-violet (UV) or by plasma treatment. All films were analyzed before and after grafting. X-ray photoelectron spectroscopy (XPS) measurements were used to evaluate TPU surfaces functionalization. HEMA grafting was confirmed by the increase of the hydroxyl (OH) groups' concentration at the surface of the films. Atomic force microscopy (AFM) analysis was done to evaluate the surface topography of the biomaterials. Results showed that the roughness of the surface decreased when HEMA was grafted, especially for plasma treated samples. After grafting the films' hydrophilicity was improved, as well as the polar component of the surface energy, by 15-30%. Hydrophobic recovery studies using milli Q water or PBS were also performed to characterize the stability of the modified surface, showing that the films maintained their surface properties along time. Furthermore, blood-contact tests were performed to evaluate haemolytic and thrombogenic potential. The results obtained for HEMA grafted surfaces, using plasma treatment, confirmed biomaterials biocompatibility and low thrombogenicity. Finally, the cytotoxicity and antibacterial activity of the materials was assessed through in vitro assays for both modified films. The obtained results showed enhanced bactericidal activity, especially for the films modified with plasma.

Fluorescence diffuse optical tomography using the split Bregman method.

PURPOSE: Standard image reconstruction methods for fluorescence Diffuse Optical Tomography (fDOT) generally make use of L2-regularization. A better choice is to replace the L2 by a total variation functional that effectively removes noise while preserving edges. Among the wide range of approaches available, the recently appeared Split Bregman method has been shown to be optimal and efficient. Furthermore, additional constraints can be easily included. We propose the use of the Split Bregman method to solve the image reconstruction problem for fDOT with a nonnegativity constraint that imposes the reconstructed concentration of fluorophore to be positive. METHODS: The proposed method is tested with simulated and experimental data, and results are compared with those yielded by an equivalent unconstrained optimization approach based on Gauss-Newton (GN) method, in which the negative part of the solution is projected to zero after each iteration. In addition, the method dependence on the parameters that weigh data fidelity and nonnegativity constraints is analyzed. RESULTS: Split Bregman yielded a reduction of the solution error norm and a better full width at tenth maximum for simulated data, and higher signal-to-noise ratio for experimental data. It is also shown that it led to an optimum solution independently of the data fidelity parameter, as long as the number of iterations is properly selected, and that there is a linear relation between the number of iterations and the inverse of the data fidelity parameter. CONCLUSIONS: Split Bregman allows the addition of a nonnegativity constraint leading to improve image quality.