Thymine adsorption on two-dimensional boron nitride structures: first-principles studies.

First-principles total-energy calculations were performed to investigate the structural and electronic properties of thymine (T) adsorption on pristine and Al-doped two-dimensional hexagonal boron nitride (2D-hBN) surfaces. Periodic density functional theory, as developed in the PWscf code of the quantum espresso package, was applied. The pseudopotential theory was used to deal with electron-ion interactions. The generalized gradient approximation was applied to treat the exchange-correlation energies. Van der Waals interactions were incorporated in the calculations. Considering T as an elongated molecule and the interactions through one oxygen atom of the molecule ring, two geometries were explored in pristine and Al-doped systems: in (1) the ring side O interacts with B, and (2) the O at the molecule end interacting with the B. The pristine case yields (4 × 4-a), (5 × 5-b) and (6 × 6-b) as the ground states, , while the doped system shows (4 × 4-a), (5 × 5-a) and (6 × 6-a) as the ground states. Calculations of the adsorption energies indicate chemisorption. Doping enhances the surface reactivity, inducing larger binding energies. The total density of states (DOS) was calculated and interpreted with the aid of the projected DOS. Below the Fermi energy, the DOS graphs indicate that p orbitals make the largest contributions. Above the Fermi level, the DOS is formed mainly by -s and H-s orbitals. The DOS graphs indicate that the structures have non-semiconductor behavior.

Macrophage integrins modulate response to ultra-high molecular weight polyethylene particles and direct particle-induced osteolysis.

Aseptic loosening due to peri-prosthetic osteolysis is one of the primary causes for failure of artificial joint replacements. Implant-derived wear particles, often ultra-high molecular weight polyethylene (UHMWPE) microparticles, initiate an inflammatory cascade upon phagocytosis by macrophages, which leads to osteoclast recruitment and activation, ultimately resulting in osteolysis. Investigation into integrin receptors, involved in cellular interactions with biomaterial-adsorbed adhesive proteins, is of interest to understand and modulate inflammatory processes. In this work, we investigate the role of macrophage integrins Mac-1 and RGD-binding integrins in response to UHMWPE wear particles. Using integrin knockout mice as well as integrin blocking techniques, reduction in macrophage phagocytosis and inflammatory cytokine secretion is demonstrated when these receptors are either absent or blocked. Along this line, various opsonizing proteins are shown to differentially modulate microparticle uptake and macrophage secretion of inflammatory cytokines. Furthermore, using a calvarial osteolysis model it is demonstrated that both Mac-1 integrin and RGD-binding integrins modulate the particle induced osteolysis response to UHMWPE microparticles, with a 40% decrease in the area of osteolysis by the absence or blocking of these integrins, in vivo. Altogether, these findings indicate Mac-1 and RGD-binding integrins are involved in macrophage-directed inflammatory responses to UHMWPE and may serve as therapeutic targets to mitigate wear particle induced peri-prosthetic osteolysis for improved performance of implanted joints.

Integrin-directed modulation of macrophage responses to biomaterials.

Macrophages are the primary mediator of chronic inflammatory responses to implanted biomaterials, in cases when the material is either in particulate or bulk form. Chronic inflammation limits the performance and functional life of numerous implanted medical devices, and modulating macrophage interactions with biomaterials to mitigate this response would be beneficial. The integrin family of cell surface receptors mediates cell adhesion through binding to adhesive proteins nonspecifically adsorbed onto biomaterial surfaces. In this work, the roles of integrin Mac-1 (αMß2) and RGD-binding integrins were investigated using model systems for both particulate and bulk biomaterials. Specifically, the macrophage functions of phagocytosis and inflammatory cytokine secretion in response to a model particulate material, polystyrene microparticles were investigated. Opsonizing proteins modulated microparticle uptake, and integrin Mac-1 and RGD-binding integrins were found to control microparticle uptake in an opsonin-dependent manner. The presence of adsorbed endotoxin did not affect microparticle uptake levels, but was required for the production of inflammatory cytokines in response to microparticles. Furthermore, it was demonstrated that integrin Mac-1 and RGD-binding integrins influence the in vivo foreign body response to a bulk biomaterial, subcutaneously implanted polyethylene terephthalate. A thinner foreign body capsule was formed when integrin Mac-1 was absent (~30% thinner) or when RGD-binding integrins were blocked by controlled release of a blocking peptide (~45% thinner). These findings indicate integrin Mac-1 and RGD-binding integrins are involved and may serve as therapeutic targets to mitigate macrophage inflammatory responses to both particulate and bulk biomaterials.

2014 updated recommendations for preschool vision screening: Guidelines for Filipino children entering the Philippine public school system

@#In 2004, the University of the Philippines Manila published the Philippine Guidelines on Periodic Health Examination (PHEX): Effective Screening for Diseases among Apparently Healthy Filipinos. 1 The document was envisioned to “contribute… to the quality and efficiency of health care and health maintenance for all Filipinos… It was an appeal for rational medical decision-making, and an important step toward “equitable distribution of health and health resources.” The guidelines were prepared by designated task forces, with vision disorders, specifically vision impairment, and glaucoma identified as areas of interest. PHEX recommendations were drafted using standardized principles and a common protocol, with each statement undergoing four phases of development: (1) preparation of the evidence- based draft; (2) en banc meeting that gave panelists a chance to assess and revise the draft, where issues of feasibility, resource limitations, value judgment, and experts’ opinions were taken into account. A consensus was declared when at least 75% agreed on a recommendation; (3) for unresolved issues, modified Delphi technique was employed by correspondence until a consensus was reached or a maximum of three circulations were accomplished. If still unresolved, the issue was labeled as such and included in the final draft; (4) lastly, a public forum was conducted before the final draft was written. In this manner, the recommendations for Screening for Visual Impairment were written by the Task Force for Vision Disorders.

Antibacterial effects of zinc oxide nanorod surfaces.

Antibacterial coating approaches are being investigated to modify implants to reduce bacterial adhesion and viability in order to reduce implant-associated infection. Nanostructured materials possess unique surface properties, and nanotopographic surfaces have been reported to modulate bacterial adhesion. Zinc oxide (ZnO) films presenting well-controlled nanorod surface structures have recently been developed. To assess the efficacy of ZnO nanorod surfaces as an anti-bacterial coating, we evaluated bacterial adhesion and viability, compared to sputtered ZnO substrates (a relatively flat control) and glass substrates (as a reference). Common implant-associated pathogens, Pseudomonas aeruginosa and Staphylococcus epidermidis were investigated. The number of adherent P. aeruginosa on ZnO nanorod surfaces was found to be reduced compared to glass and sputtered ZnO, while the adherent number of S. epidermidis on the ZnO nanorods was equivalent to glass. Regarding bacteria viability, the ZnO nanorod and sputtered ZnO surfaces demonstrated a modest, but significant bactericidal effect on adherent P. aeruginosa, killing 2.5-fold and 1.7-fold more over the number of dead P. aeruginosa on glass, respectively. A greater bactericidal effect of ZnO substrates on S. epidermidis was found, with sputtered ZnO and ZnO nanorod substrates killing -20-fold and 30-fold more over the number of dead S. epidermidis on glass, respectively. These data support the further investigation and optimization of ZnO nanorod coatings with potential for bacterial adhesion resistance and bactericidal properties.

Microparticle surface modifications targeting dendritic cells for non-activating applications.

Microparticulate systems for delivery of therapeutics to DCs for immunotherapy have gained attention recently. However, reports addressing the optimization of DC-targeting microparticle delivery systems are limited, particularly for cases where the goal is to deliver payload to DCs in a non-activating fashion. Here, we investigate targeting DCs using poly (d lactide-co-glycolide) microparticles (MPs) in a non-stimulatory manner and assess efficacy in vitro and in vivo. We modified MPs by surface immobilizing DC receptor targeting molecules - antibodies (anti-CD11c, anti-DEC-205) or peptides (P-D2, RGD), where anti-CD11c antibody, P-D2 and RGD peptides target integrins and anti-DEC-205 antibody targets the c-type lectin receptor DEC-205. Our results demonstrate the modified MPs are neither toxic nor activating, and DC uptake of MPs in vitro is improved by the anti-DEC-205 antibody, the anti-CD11c antibody and the P-D2 peptide modifications. The P-D2 peptide MP modification significantly improved DC antigen presentation in vitro both at immediate and delayed time points. Notably, MP functionalization with P-D2 peptide and anti-CD11c antibody increased the rate and extent of MP translocation in vivo by DCs and MΦs, with the P-D2 peptide modified MPs demonstrating the highest translocation. This work informs the design of non-activating polymeric microparticulate applications such as vaccines for autoimmune diseases.

Contributions of surface topography and cytotoxicity to the macrophage response to zinc oxide nanorods.

Macrophages associated with implanted biomaterials are primary mediators of chronic inflammation and foreign body reaction to the implant. Hence, various approaches have been investigated to modulate macrophage interactions with biomaterial surfaces to mitigate inflammatory responses. Nanostructured materials possess unique surface properties, and nanotopography has been reported to modulate cell adhesion and viability in a cell type-dependent manner. Zinc oxide (ZnO) has been investigated in a number of biomedical applications and surfaces presenting well-controlled nanorod structures of ZnO have recently been developed. In order to investigate the influence of nanotopography on macrophage adhesive response, we evaluated macrophage adhesion and viability on ZnO nanorods, compared to a relatively flat sputtered ZnO controls and using glass substrates for reference. We found that although macrophages are capable of initially adhering to and spreading on ZnO nanorod substrates, the number of adherent macrophages on ZnO nanorods was reduced compared to ZnO flat substrate and glass. Additionally adherent macrophage number on ZnO flat substrate was reduced as compared to glass. While these data suggest nanotopography may modulate macrophage adhesion, reduced cell viability on both sputtered and nanorod ZnO substrate indicates appreciable toxicity associated with ZnO. Cell death was apparently not apoptotic, given the lack of activated caspase-3 immunostaining. A decrease in viable macrophage numbers when ZnO substrates were present in the same media verified the role of ZnO substrate dissolution, and dissolved levels of Zn in culture media were quantified. In order to determine long-term physiological responses, ZnO nanorod-coated and sputtered ZnO-coated polyethylene terephthalate (PET) discs were implanted subcutaneously in mice for 14 d. Upon implantation, both ZnO-coated discs resulted in a discontinuous cellular fibrous capsule indicative of unresolved inflammation, in contrast to uncoated PET discs, which resulted in typical foreign body capsule formation. In conclusion, although ZnO substrates presenting nanorod topography have previously been shown to modulate cellular adhesion in a topography-dependent fashion for specific cell types, this work demonstrates that for primary murine macrophages, cell adhesion and viability correlate to both nanotopography and toxicity of dissolved Zn, parameters which are likely interdependent.

Recovery of ventricular function with a left ventricular axial pump in a patient with end-stage toxic cardiomyopathy not a candidate for heart transplantation: first experience in Spain.

BACKGROUND: Toxic cardiomyopathies are rare and the most frequent cause are anthracycline compounds. Early acute toxicity can be reversible, but at present the only effective therapy for late end-stage anthracycline cardiomyopathy seems to be a heart transplantation. Currently, this transplantation is contraindicated in cases of cancer, at least during the first 4 or 5 years. Recently, implantable axial pumps have shown good results and are used with increasing frequency as destination therapy. METHODS: We present a case of end-stage heart failure due to a toxic cardiomyopathy after a bilateral breast cancer treated with resection and chemotherapy (doxorubicin and trastuzumab). Ejection fraction was 23% with dobutamine. A left ventricular axial pump (Incor) was implanted. RESULTS: The immediate postoperative course was uneventful. The left ventricular function improved and on the fourth month the ejection fraction was 55%. On postoperative day 135, the pump was explanted. After 1.5 years, the patient is doing well, with an ejection fraction of 57%. CONCLUSION: This is the first application of an implantable axial pump in Spain. Although toxic cardiomyopathies are rare, in cases of late end-stage left ventricular failure and when the heart transplantation is contraindicated, the implantation of an axial pump can be the solution. The results in previous cases are unknown, although it is possible, as in our case.

Clinical evolution of heart transplantation in patients with previous valvular cardiomyopathy.

OBJECTIVE: Heart transplantation (HT) due to valvular cardiomyopathy is rare, namely, about 3% of cases in the Registry of the International Society for Heart and Lung Transplantation (ISHLT). Usually, these patients present some risk factors such as previous valvular operations and pulmonary hypertension. Since there are few studies in the literature, we retrospectively analyzed our early and long-term results. MATERIALS AND METHODS: We studied our experience in 22 HT cases for valvular cardiomyopathy (9.3% of our total experience), namely, 12 men and 10 women, of overall mean age of 52.6 +/- 10 years. Five patients had mitral; 8, aortic; and 1, tricuspid valve disease; 7 had double valve disease and 1, triple valve disease. Nineteen patients (87%) had been operated previously between 1 and 4 times. The mean ejection fraction was 23% +/- 7.3% and the mean New York Heart Association (NYHA) functional class was 3.7. Fifty-three percent of the patients had pulmonary hypertension. Two patients were operated as an emergency "O." We used the standard HT technique. RESULTS: Four patients (18%) were reoperated due to hemorrhage. The hospital mortality was 2 cases (9%). Another patients (9%) died on follow-up due to cardiac allograft vasculopathy. All surviving patients have been followed to the end of 2006. The mean follow-up has been 72 +/- 53 months. They are functional class I or II. CONCLUSIONS: HT for this indication was more frequent in our experience than in the Registry of the ISHLT. The immediate and long-term results were good, with an 82% mean survival at 6 years. HT can be a good treatment for patients with valvular cardiomyopathy and bad ventricular function and/or multiple valvular reoperations.

Quantitation and stability of piperacillin and tazobactam in plasma and ultrafiltrate from patients undergoing continuous venovenous hemofiltration by HPLC.

Simple and reproducible HPLC methods for the determination of piperacillin and tazobactam have been developed and a complete stability study carried out. The method for piperacillin plasma samples consisted of protein precipitation with methanol using penicillin G as internal standard. No sample preparation was needed for ultrafiltrate samples. Tazobactam sample preparation involved protein precipitation with acetonitrile and the removal of lipids with dichloromethane. Piperacillin separation was performed on a microBondapack C(18) column (300 x 3.9, 10 microm) and tazobactam on a Novapack C(18) column (150 x 3.9, 4 microm) with UV detection set at 229 and 225 nm, respectively. The mobile phase consisted of phosphate buffer-acetonitrile, delivered at 1.5 mL[sol ]min. Calibration curves determination coefficients were >or=0.999 and response factors CV% < 5%. Intra- and inter-assay precision and accuracy of the quality control and limit of quantification were satisfactory. Plasma and ultrafiltrate samples were stable at -20 and -80 degrees C for 2 months and after three freeze-thaw cycles. In the chromatographic rack, tazobactam ultrafiltrate samples were stable for 24 h and plasma samples for 12 h, piperacillin ultrafiltrate samples for 8 h, but plasma samples for only 4 h. Storage of piperacillin samples at 4 degrees C until analysis is recommended. Piperacillin was stable in the presence of tazobactam.

Efectos del antagonista de las benzodiacepinas Flumazenil, en pacientes con trauma craneoencefálico grave / Effects of the benzodiazepine antagonist flumazenyl in patients with severe cranioencephalic traumatism

Objetivos: Las benzodiacepinas son drogas sedantes utilizadas frecuentemente en pacientes con trauma craneoencefálico. Su empleo altera la valoración neurológica del paciente, por lo que es útil disponer de un antagonista. La reversión de sus efectos puede alterar las respuestas hemodinámicas y neurológicas de estos pacientes. Nos proponemos analizar estas respuestas en un grupo de pacientes con trauma craneoencefálico grave en tratamiento con benzodiacepinas en perfusión continua a los que se revierte su acción con el antagonista flumazenil. Métodos: Estudio prospectivo, intervencional, en pacientes con trauma craneal grave (tomografía computadorizada craneal en todos los pacientes), ingresados en una UCI de un hospital universitario, con monitorización de presión intracraneal (PIC) y sin datos de hipertensión intracraneal y estabilidad hemodinámica. Tras 48 horas de perfusión de benzodiacepinas, reversión con 0.5-1 mg de flumazenil. Valoración antes y después (5 minutos) de nivel de conciencia (GCS), PIC, tensión arterial media (TAM), frecuencia cardíaca, presión de perfusión cerebral (PPC).Resultados: Se incluyeron 25 pacientes con trauma cerrado. Edad media: 31,5 +/-12,94 años. Varones 80 por ciento. Lesiones focales 72 por ciento. Lesiones asociadas 48 por ciento. GCS previo 5,0+/-2,6 PIC basal: 15,16+/-5,5, PPC: 75,22 +/-15,1. (TAM): 90,84+/-13,4 y frecuencia cardíaca: 87,1 +/-21,1. Tras flumazenil GCS: 6,64 +/-3,34 (p< 0,05) PIC: 20,76 +/-12,3 (p<0,05). TAM: 98,2 +/-23,1 (NS). PPC: 77,58 +/-17,6 (NS).Conclusiones: Aunque nuestra serie tiene el sesgo de ser un grupo de pacientes sin hiperPIC, el GCS se elevó tras flumazenil, pero se acompañó de aumento de la PIC, contraindicando su empleo en pacientes incluso con PIC normal si se sospecha trauma craneal (AU)