Laser de femtosegons en forma de 8 basat en EDFA i controlat per Arduino

2013/201

Laser de femtosegons en forma de 8 basat en EDFA i controlat per Arduino

2013/201

Toxicology review in metal nanoparticles: Approximation in gold and cobalt ferrite nanoparticles

The toxicity of nanoparticles is under discussion. The great diversity of nanoparticles (different chemical composition, size, shape, surface recovery among others) makes it difficult to establish a criterion for determining the effects of human and environmental exposure. Gold Nanoparticles are considered biocompatible because they are composed of an inert material. These nanoparticles are used for different medical purposes, such as labeling, delivering, heating and sensing. Their effects can vary depending on their coating, size, and shape. Nevertheless, inert particles can produce morphologic changes, loss of function, inflammation or cell damage, therefore they must be studied with more detail. Superparamagnetic properties of cobalt ferrite nanoparticles are used for biosensing applications, tumor treatment by hyperthermia and as contrast agent in magnetic resonance imaging (MRI) among other applications. Although they are also considered biocompatible, some studies show some degree of dose and size depending cytotoxicity and genotoxicity. Both kinds of nanoparticles, mainly focused to biomedical industry, have been studied in different fields of toxicology. In this paper we have summarized some reports in an interdisciplinary review.Peer reviewe

Studying Closed Hydrodynamic Models of "In Vivo" DNA Perfusion in Pig Liver for Gene Therapy Translation to Humans.

Expressing exogenous genes after naked DNA delivery into hepatocytes might achieve sustained and high expression of human proteins. Tail vein DNA injection is an efficient procedure for gene transfer in murine liver. Hydrodynamic procedures in large animals require organ targeting, and improve with liver vascular exclusion. In the present study, two closed liver hydrofection models employing the human alpha-1-antitrypsin (hAAT) gene are compared to reference standards in order to evaluate their potential clinical interest.A solution of naked DNA bearing the hAAT gene was retrogradely injected in 7 pig livers using two different closed perfusion procedures: an endovascular catheterization-mediated procedure (n = 3) with infrahepatic inferior vena cava and portal vein blockage; and a surgery-mediated procedure (n = 4) with completely sealed liver. Gene transfer was performed through the suprahepatic inferior cava vein in the endovascular procedure and through the infrahepatic inferior vena cava in the surgical procedure. The efficiency of the procedures was evaluated 14 days after hydrofection by quantifying the hAAT protein copies per cell in tissue and in plasma. For comparison, samples from mice (n = 7) successfully hydrofected with hAAT and healthy human liver segments (n = 4) were evaluated.Gene decoding occurs efficiently using both procedures, with liver vascular arrest improving its efficiency. The surgically closed procedure (sealed organ) reached higher tissue protein levels (4x10^5- copies/cell) than the endovascular procedure, though the levels were lower than in human liver (5x10^6- copies/cell) and hydrofected mouse liver (10^6- copies/cell). However, protein levels in plasma were lower (p<0.001) than the reference standards in all cases.Hydrofection of hAAT DNA to "in vivo" isolated pig liver mediates highly efficient gene delivery and protein expression in tissue. Both endovascular and surgically closed models mediate high tissue protein expression. Impairment of protein secretion to plasma is observed and might be species-related. This study reinforces the potential application of closed liver hydrofection for therapeutic purposes, provided protein secretion improves

hAAT gene translation index in liver tissue.

<p>Fig 3 represents the gene translation index per cell, calculated per ELISA, after both the endovascular and surgery closed perfusion procedures. Translation in each liver lobe is represented (mean ± SD). First letter: R = right, L = left; Second letter: M = medial, L = lateral; Number: 1 = upper, 2 = lower. Statistical analysis: linear mixed model with pig as random factor, hAAT protein as response variable, and group, liver lobe and their interaction as explicative variables.</p

hAAT Immunohistochemistry.

<p>Non-transfected pig liver hAAT staining (a; 40x) versus transfection employing endovascular closed catheterization (b; 40x). hAAT protein staining in liver sections of transfected mice is shown (c; 40x); human liver hAAT immunostaining can be observed (d; 40x). Black arrows indicate representative specific immunohistochemical reaction against hAAT protein in pig samples. Tissue was counterstained with hematoxylin.</p

Open and closed endovascular catheterization procedure.

<p>The endovascular closed procedure is represented in Fig 1A. A schematic representation of the procedure is provided. An 8Fr balloon introducer and a 10Fr balloon catheter were placed in the vena cava, limiting entrance to the liver. Another transhepatic 10Fr balloon catheter was placed in the portal vein to block outflow. Fig 1B provides a schematic representation of the surgery closed model. After midline laparotomy, the liver is exposed and its vasculature (veins and artery), except the infrahepatic inferior vena cava, is referenced and ligated, thus completely sealing the organ. Retrograde gene transfer is performed through an 11 Fr catheter.</p

Pig hAAT gene decoding by catheterization and surgical closed procedure versus standards.

<p>The average copy contents (mean ± SD) of hAAT DNA, RNA and protein (tissue and plasma) in pigs after closed liver hydrofection (A) are compared with those obtained in standards (human liver and hydrodynamically transfected mouse liver, B). Tissue indexes are shown as copy number per cell in each case. Protein expression in plasma is expressed as concentration (μg/ml). Statistical analysis: Linear mixed model with expression level as response variable and sample type (DNA, RNA, protein or plasma), species and their interaction as explicative variables; statistically significant interaction between pig and protein in serum (p < 0.001). †: p<0.05 (p = 0.027); ††: p<0.01 (p = 0.007).</p

hAAT protein expression in liver tissue.

<p>hAAT protein expression in liver tissue is represented. The part at left corresponds to controls. Positive controls: pure hAAT protein (1 and 5 ng). Negative control: homogenate from eGFP transfected pig liver tissue (50 μg of total protein). The part at right in the figure represents hAAT protein presence in liver tissue after both the endovascular and surgery closed perfusion procedures. Translation in each liver lobe is represented. Equivalent amounts of total protein from distal and proximal tissue samples of each liver lobe were mixed. First letter: R = right, L = left; Second letter: M = medial, L = lateral; The id of pigs follows the internal nomenclature employed in our laboratory.</p

hAAT protein concentration in plasma on day 14.

<p>hAAT protein concentration in plasma on day 14.</p