Proliferación de células madres mesenquimales obtenidas de tejido gingival humano sobre una matriz de quitosano: estudio in vitro / Proliferation of mesenchymal stem cells from human gingival tissue on chitosan scaffold: an in vitro study

Objetivo: Comprobar la proliferación de células madres mesenquimales (MSCs) provenientes de tejido conjuntivo gingival humano sobre una matriz de quitosano. Método: Estudio experimental in vitro en el cual se aislaron MSCs a partir de cultivos por explante de tejido conjuntivo gingival. La presencia de MSCs, se caracterizó mediante citometría de flujo, utilizando para ello anticuerpos CD34, CD45, CD73, CD90, CD105, diferenciación hacia tres linajes celulares: adipocitos, osteoblastos y condroblastos. La diferenciación fue corroborada mediante microscopía óptica con tinciones Oil Red, Alizarin Red y Safranina O respectivamente. La matriz de quitosano fue analizada mediante microscopía óptica. Las MSCs en pasaje 5, fueron sembradas en presencia de la matriz de quitosano. La proliferación de las células madres fue analizada mediante microscopía óptica y tinción con cristal violeta. Resultados: A partir del explante de tejido gingival humano se obtuvieron MSCs, que cumplieron con los criterios de caracterización morfológica y fenotípica correspondiente a una MSC. Las MSC adoptaron una morfología fibroblastoide, adherencia al plástico, confluencia de un 80 por ciento y sobre un 90 por ciento expresaron los marcadores CD73, CD90 y CD105 y bajo un 10 por ciento fueron negativas para CD34, y CD45 por técnica de citometria de flujo. Las MSC cultivadas en presencia de quitosano proliferan, sin embargo observamos que a mayor concentración de quitosano en el cultivo disminuye la proliferación y densidad celular. La matriz de quitosano en presencia del medio de cultivo pierde sus propiedades físicas, disolviéndose y formando un gel no transportable. Conclusiones: A pesar de existir proliferación celular de MSCs de origen gingival humano en presencia de la matriz de quitosano, su utilidad como andamiaje y medio de transporte de MSC es deficiente debido a que se alteran sus propiedades físicas, disolviéndose y formando un gel no transportable en contacto con el medio de...

Aim: The purpose of this study was to assess the proliferation of mesenchymal stem cells (MSCs) from human gingival tissue on chitosan matrix. Methods: Experimental study in vitro. Gingival connective tissue samples were obtained from healthy volunteers from the maxillary tuberosity. The explants were minced and cultured on tissue culture dishes. MSC were characterized by flow cytometry using markers for CD34, CD45, CD73, CD90, CD105 and for differentiation into, adipogenic, osteogenic and chondrogenic lineages. The tissue differentiated was analyzed with light microscopy and evaluated by culture staining using Oil Red, Alizarin Red y Safranina O respectively. MSC from passage 5 were cultured with chitosan scaffold. Proliferation of MSC was analyzed with light microscopy and crystal violet staining. Results: MSCs were obtained from gingival explants, and developed the standard of the morphologic and phenotypic characterization as a stem cell. The MSC adopted a fibroblastoid morphology, adherence to plastic, confluence of 80 percent and over 90 percent were consistently positive for CD90, CD105, CD73 markers and under 10 percent were negative for hematopoietic markers CD34 and CD45 by flow cytometry analysis. The MSC cultured in presence of chitosan matrix proliferated, however complete medium, it was dissolved forming a gel structure. We also observed that at higher concentrations of chitosan, MSC has less density and growth. Chitosan matrix in presence of cell culture medium loses physical properties, dissolving and forming a non-transportable gel. Conclusions: Despite the existence of proliferation of MSCs from human gingival tissue with chitosan matrix, its ability to act as a cell carrier and scaffold is deficient, since its physical properties are altered, dissolving and forming a non-transportable gel in contact with cell culture medium.

Analgesic activity of Ugni molinae (murtilla) in mice models of acute pain.

Leaf extracts of Ugni molinae Turcz. (Myrtaceae) are used in Chilean folk medicine as analgesic and anti-inflammatory. The antinociceptive effect of dichloromethane (DCM), ethyl acetate (EA) and methanol (ME) leaf extracts was assessed by intraperitoneal, oral and topical administration in writhing, tail flick, and tail formalin tests in mice. The extracts showed a dose-dependent antinociceptive activity in all the assays under different administration routes. The ED(50) values for the different tests for the DCM, EA, ME extract and reference drug (ibuprofen) were as follows. Writhing test in acetic acid (i.p. administration): 0.21, 0.37, 1.37 and 0.85mg/kg, respectively; tail flick test (oral administration): 199, 189, 120 and 45.9mg/kg. The EC(50) values for tail flick test were (topical administration): 2.0, 0.35, 1.4 and 8.2% (w/v), respectively; and the topical analgesic effects were (formalin assay) 75.5, 77.5, 31.6 and 76.5%, respectively. Ugni molinae extracts produce antinociception in chemical and thermal pain models through a mechanism partially linked to either lipooxygenase and/or cyclooxygenase via the arachidonic acid cascade and/or opioid receptors. Flavonoid glycosides and triterpenoids have been isolated from the plant and can be associated with the observed effect. Our results corroborate the analgesic effects of Ugni molinae, and justify its traditional use for treating pain.

The disposition of nifurtimox in the rat isolated perfused liver: effect of dose size.

The disposition of nifurtimox was studied in the rat isolated perfused liver using a recirculating system. The drug was administered as a bolus (5.0, 15.0 or 30.0 micrograms mL-1), and its disappearance was monitored by analysing perfusate samples. In all experiments perfusate disappearance was monoexponential, and no significant difference was found between the three doses for the elimination constant (0.016, 0.011 and 0.012 min-1, respectively), half-life (46.6, 65.8 and 66.8 min, respectively), extraction rate (0.128, 0.091 and 0.099, respectively) and distribution volume (41.1, 47.3 and 30.7 mL g-1, respectively). At 30 micrograms mL-1 the hepatic clearance was lower than the other concentrations of nifurtimox (0.66, 0.51 and 0.34 mL min-1 g-1, respectively). Relatively little parent drug was recovered from the liver at the end of the perfusions. In summary, nifurtimox is cleared slowly from the rat isolated perfused liver, is poorly extracted by hepatocyte cells and is completely metabolized from 2 to 4 h after perfusion.

Luxación congénita de cadera: diagnóstico precoz en Cunco / Congenital luxation of the hip: early diagnosis in Cunco

Se presenta un trabajo de Investigación prospectiva en Medicina Primaria en el que se evalúan 214 RN en el Hospital de Cunco, IX Región, durante Junio-1988 a Junio-1989. Se detectan 2 casos de luxación congénita de Cadera (1 x 1000 RN vivos) y 6 Displasias de Cadera (1 x 36 RN vivos) en base a diagnóstico clínico por médicos generales mediante el signo de Ortolani-Barlow. Se confirmó clínicamente por el especialista en 76,4% y radiológicamente en el 30,7 de los pacientes