Study of nitrogen implantation in Ti surface using plasma immersion ion implantation & deposition technique as biocompatible substrate for artificial membranes.

The present investigation reports the modification of Ti substrates by a plasma technique to enhance their physio-chemical properties as biocompatible substrates for the deposition of artificial membranes. For that purpose, nitrogen ions are implanted into Ti substrate using the plasma immersion ion implantation & deposition (PIII&D) technique in a capacitively coupled radio frequency plasma. The plasma was characterized using optical emission spectroscopy, together with radio frequency compensated Langmuir probe, while the ion current towards the substrate was measured during the implantation process using an opto-electronic device. X-ray photoelectron spectroscopy (XPS) was used for chemical analysis of the surface, confirming the presence of δ-TiN. The penetration depth of the nitrogen ions into the Ti substrate was measured using secondary ions mass spectroscopy (SIMS) while the morphological changes were observed using atomic force microscopy (AFM). A calorimetric assay was used to prove that the TiN samples maintain the biocompatibility of the untreated Ti surface with its native oxide layer. The ion implantation increases the load bearing ability of Ti surface by the formation of α-Ti(N) and δ-TiN phases on the sub-surface of Ti, and maintains the bio compatibility of Ti surface. After the plasma treatment a thin layer of chitosan (CH) was deposited in order to provide a moisturizing matrix for the artificial membrane of 1,2-dipalmitoyl-sn-3- phosphor glycerocholine (DPPC). The CH and subsequently the DPPC were deposited on the plasma deposited TiN substrate by using physical vapor deposition. The formation of artificial membranes was confirmed by AFM, measuring the topography at different temperatures and performing force curves.

Mesotelioma pleural: estudio morfológico de 9 casos de autopsia / Pleural mesothelioma: morphological study of 9 cases of autopsy

Se revisaron todos los protocolos de autopsia del Departamento de Anatomía Patológica de la Facultad de Medicina de la Pontificia Universidad Católica de Chile en el período enero de 1960-diciembre de 1985, extrayéndose los casos que correspondían a un mesotelioma pleural. Los casos fueron analizados en cuanto a edad y sexo de los pacientes, hallazgos patológicos, enfermedades asociadas, tipo histológico del mesotelioma, y las causas de muerte. De un total de 5696 autopsias para el período 1960-1985, se encontraron 9 casos de mesotelioma pleural, o un 0,16% del total, de los cuales 7 se observaron en hombres (78%) y 2 en mujeres (22%). La edad promedio de los casos fue 47 años con un rango de 1,58 a 70 años. Dos casos se consideraron benignos (22%) y 7 malignos (78%). El grupo maligno estaba constituído por 4 casos de la variedad epitelial y 3 de tipo mixto, no observándose ningún caso de tipo sarcomatoso. Al momento de la necropsia, un caso estaba limitado a la pleura (estadio I), 3 presentaban una invasión tumoral bajo el diafragma (estadio II), y los 3 restantes presentaban metástasis a distancia (estadio IV). La muerte de los pacientes estuvo relacionada con embolias pulmonares múltiples en un caso, bronconeumonía en 3, septicemia en 2, y no se demostró otra causa que la tumoral en los 3 casos restantes