RESUMO
The preparation procedure of zero magnetic remanence superparamagnetic white paper by means of three-layer membrane configuration (sandwiched structure) is presented. The cellulose acetate fibrous membranes were prepared by electrospinning. The middle membrane layer was magnetically loaded by impregnation with an aqueous ferrofluid of 8 nm magnetic iron oxide nanoparticles colloidally stabilized with a double layer of oleic acid. The nanoparticles show zero magnetic remanence due to their very small diameters and their soft magnetic properties. Changing the ferrofluid magnetic nanoparticle volume fraction, white papers with zero magnetic remanence and tunable saturation magnetization in the range of 0.5-3.5 emu/g were prepared. The dark coloring of the paper owing to the presence of the black magnetite nanoparticles was concealed by the external layers of pristine white cellulose acetate electrospun fibrous membranes.
RESUMO
OBJECTIVE: The aim of this study was to establish the diagnostic accuracy of high-field magnetic resonance imaging (MRI) at 7 Tesla (T) compared with that of stereomicroscopic autopsy for assessing first trimester fetuses. METHODS: Nine consecutive cases of first trimester fetuses resulting from spontaneous and therapeutic pregnancy termination were considered. The cases were divided into two groups according to gestational age: the Embryo Group with cases of nine to 10 gestational weeks (GWs) and the Fetus Group with cases of 13 GWs. The first group was scanned using three-dimensional fast imaging with steady state precession (3D FISP), and the second group was scanned using a two-dimensional (2D) turbo spin-echo high-resolution T2-weighted imaging (T2 WI) protocol. A radiologist and two embryologists interpreted the images. All cases were evaluated by invasive autopsy, with pathologist blinded to the imaging results. In total, the database included 270 items for evaluation (9 cases × 30 structures/case). RESULTS: The global agreement between fetal high-field virtopsy and microscopic or stereomicroscopic autopsy was evaluated using 225 evaluation items visible by both methods. Overall, using microscopic examination and stereomicroscopic autopsy as the gold standard, fetal high-field virtopsy had a sensitivity of 94.6% [95% CI, 87.2-98.3] and a specificity of 97.6% [95% CI, 95-98.8]. The positive predictive value (PPV) was 93% [95% CI, 85.7-96.6], and the negative predictive value (NPV) was 98.2% [95% CI, 95.7-99.4]. Cohen kappa coefficient of agreement was k = 0.92 [95% CI, 0.82-0.97], and the McNemar test showed p = 1.00. CONCLUSIONS: Virtual autopsy using high-field MRI at 7 T can be considered a safe alternative approach to stereomicroscopic autopsy for the assessment of fetal structural anomalies at the end of the first trimester of pregnancy.
Assuntos
Feto Abortado/patologia , Feto/patologia , Imageamento por Ressonância Magnética/métodos , Microscopia/métodos , Primeiro Trimestre da Gravidez , Feto Abortado/diagnóstico por imagem , Autopsia/métodos , Percepção de Profundidade , Feminino , Morte Fetal , Feto/diagnóstico por imagem , Idade Gestacional , Humanos , Imageamento Tridimensional/métodos , Valor Preditivo dos Testes , Gravidez , Sensibilidade e EspecificidadeRESUMO
Dip Pen Nanolithography technique has been employed for patterning L-Glutathione tripeptide (l-y-glutamyl-l-cysteinyl-glycine) nanostructures at specific locations on metallic Au(111) substrate. The formed supramolecular architectures were designed through straight lines and dots serving as precursors for building blocks assemblies in nano-bio-electronics applications or as template structures for functionalized particles in the form of host-guest networks. Tween 20 polyoxyethylene surfactant concentrations ranging from 0.005 to 0.1% (v/v) into initial l-Glutathione tripeptide (2 mg mL(-1)) ink solutions were sequentially tested for the improvement of the ink delivery process and to assure an optimum uniformity and homogeneity over the patterned space. A strong relationship was found between the coated atomic force microscope (AFM) cantilever within the highly effective Tween 20 activator adjuvant and the molecular diffusion along concentration gradients. An increase in the driving force for ink transport from the AFM tip has been demonstrated within the highest 0.1% (v/v) TW 20 surfactant concentration, favoring the patterning of GSH molecules routinely with sub-100 nm resolution. Self-assembled monolayers of GSH were also fabricated and characterized in the light of X-ray photoemission spectroscopy (XPS) and ellipsometric optical measurements. Adsorption from water of l-Glutathione to the gold substrate is proven to be made by the thiol group of cysteine. Theoretical DFT approaches were applied for quantum chemical studies dedicated to electronic processes underneath molecular GSH/Au(111) systems.
Assuntos
Materiais Revestidos Biocompatíveis/síntese química , Glutationa/química , Ouro/química , Nanopartículas/química , Fotografação/métodos , Impressão Tridimensional , Adsorção , Ouro/análise , Teste de MateriaisRESUMO
OBJECTIVE: Lactoferrin from human milk (HM) provides antimicrobial and anti-inflammatory action in the neonatal intestine. HM-fed, critically ill neonates often receive previously frozen milk. Freezing is known to have deleterious effects on proteins. The aim of this study was to determine the effect of low temperature storage of HM on the concentration of lactoferrin. STUDY DESIGN: HM samples were collected and stored for different periods of time and at different temperatures per Centers for Disease Control and Prevention recommendations. Lactoferrin concentrations following freezing were compared with that in fresh HM. RESULT: Lactoferrin concentrations in refrigerated HM samples were stable for 5 days. After 3 months at -18 to -20 C, the average decrease was 37%. Following storage for 6 months at -20 °C, lactoferrin decreased to 46%. CONCLUSION: Five-day refrigeration of HM does not appreciably decrease lactoferrin levels. Freezing HM for 3 months or more significantly lowers lactoferrin levels. There may be a role for occasionally providing fresh HM to critically ill neonates.
Assuntos
Armazenamento de Alimentos , Congelamento , Lactoferrina/química , Leite Humano/química , Humanos , RefrigeraçãoRESUMO
The choice of transplantation from a living donor offers advantages over a deceased donor. However, it also carries disadvantages related to donor risks in terms of health and safety. Furthermore, there are several controversial ethical aspects to be taken into account. Several national and international institutions and the scientific community have stated standards that have great influence on professional codes and legislations. Living organ donation and transplantation are to some extent regulated by parliamentary acts in most European countries. It is necessary to take a step forward to develop a legal framework to regulate all of these processes to guarantee the quality and to prevent illegal and nonethical practices. It is also necessary to develop and implement living donor protection practices not only in terms of physical health, but also to minimize potential impacts on the psychological, social, and economic spheres. Finally, an additional effort should be made to create a database model with recommendations for registration practices as part of the standardized follow-up care for the living donor. The European Living Donation (EULID) project's (http://www.eulivingdonor.eu/) main objective was to contribute to a European consensus to set standards and recommendations about legal, ethical, and living donor protection practices to guarantee the health and safety of living donors.
Assuntos
Doadores Vivos/estatística & dados numéricos , Saúde Pública , Obtenção de Tecidos e Órgãos/normas , Atitude , Ética Médica , Europa (Continente) , Humanos , Seleção de Pacientes , Fatores de Risco , Ciência/normas , Ciência/tendências , Doadores de Tecidos/psicologia , Obtenção de Tecidos e Órgãos/economia , Obtenção de Tecidos e Órgãos/legislação & jurisprudência , Obtenção de Tecidos e Órgãos/organização & administraçãoRESUMO
Insulin-dependent diabetes mellitus is a disease characterized by a deficiency of insulin secretion by beta islet cells. Integral pancreatic transplantation and islet cell transplantation represent two possibilities of replacing the beta islet cells. The aim of this paper is to analyze the main aspects of selection criteria of the pancreas donor and surgical methods of preservation for integral pancreas or islet cell transplantation. There are described the pancreas procurements realized by the Center of General Surgery and Liver Transplantation team from Fundeni Clinical Institute between December 2005-December 2006 and correlation between the donor's and pancreas features and the quality of islet cell isolation. The selection of pancreas donor and the accomplishment of pancreas procurement represent important factors in the post-transplantation course of the graft. The data from pancreas/islet cell transplantation centers suggest that the factors that influence positively the course of graft are: the donor's age, body mass index, cold ischemia time.