El cultivo celular en la investigación básica del cáncer de mama

Resumen La técnica del cultivo celular es la que ha permitido conocer el comportamientoin vitro de las células cancerosas. En esta revisión pretendemos introducir las peculiaridades básicas del cultivo celular, referido especialmente a líneas cancerosas mamarias, relacionar el origen de las líneas celulares más utilizadas en la investigación de este cáncer, mencionar las técnicas de laboratorio que pueden aplicarse sobre estos cultivos y ejemplificar la utilidad de las mismas, tomando como modelo diversos trabajos que estudian los efectos del factor de crecimiento epidérmico sobre líneas celulares hormonoindependientes de cáncer de mama.      

Detection of double-stranded RNA by ELISA and dot immunobinding assay using an antiserum to synthetic polynucleotides

An antiserum against polyinosinic-polycytidylic acid (In-Cn) was used to detect double-stranded RNA (dsRNA) by several serological techniques. DsRNA was readily detected by indirect ELISA (ELISA-I) and dot immunobinding assay (DIA). Addition of the antigen to poly-L-lysine-precoated plates and blocking with uncreamed milk powder allowed detection levels of 100 pg.ml-1 In-Cn by ELISA-I. Concentrations as low as 1 ng.ml-1 were detected by DIA using polyvinyliden difluoride (PVDF) membranes. Detection capacity with nitrocellulose membranes was 1000 times lower than with PVDF. ELISA-I and DIA enabled detection of dsRNA in enriched fractions from cucumber mosaic virus (CMV)- and citrus tristeza virus (CTV)-infected plants and from virus-infected Penicillium chrysogenum mycelium. These techniques showed similar or higher sensitivity for detection of dsRNA than separation by polyacrylamide gel electrophoresis and silver staining.     

Spontaneous loss of permanent teeth: a case report

Pathological root resorption has clinical symptoms of great importance when it appears in permanent teeth, as its etiology is not always clear. It is important to examine all local and general factors before determining its "idiopathic" cause. A case of spontaneous loss of permanent teeth in a 19 year-old female is presented. Through a meticulous study correlating the clinical history and the evolution of the symptoms, we can suspect that non-dental medical interventions requiring general anesthesia can lead to the loss of permanent teeth through root resorption.     

Redefining the significance of aneuploidy in the prognostic assessment of colorectal cancer

The aberrant content of DNA, or aneuploidy, is a hallmark of tumor cells and may be associated with malignant potential. Based on the hypothesis that aneuploidy, as a form of genetic instability, results in an increased capability to generate cell heterogeneity, we investigated whether a comprehensive assessment of aneuploidy extent and degree might be a reliable indicator of tumor aggressiveness. DNA content was determined by flow cytometry in the infiltrating front of 131 paraffin-embedded primary colorectal carcinomas collected in a prospective design. Enrichment of tumor cells by sample microdissection resulted in neoplastic cell contents above 75%. An estimate of aneuploidy, the aneuploidy index (AI), was calculated as the tumor DNA content adjusted by the percentage of diploid and aneuploid cells in G0/G1. Thirty-nine tumors were diploid, 90 hyperdiploid, and 2 hypodiploid. The mean AI in aneuploid tumors was 1.20+/-0.17 and correlated with Dukes' stage and metastasis (p < 0.05). A high AI (receiver operating characteristic curve cutoff value greater than 1.14) predicted a poorer outcome in univariate (p = 0.004) and multivariate (p = 0.01) analyses. Based on these results, we postulate that aneuploidy is the molecular engine of progression in a subset of colorectal cancers, in which the AI seems to be a sensible and independent gauge of malignant potential. The AI determination may have prognostic application in colorectal cancer, especially in low-grade tumors, which might benefit from coadjuvant therapies.     

Experimental infection of immunomodulated NOD/LtSz-SCID mice as a new model for Plasmodium falciparum erythrocytic stages

The main objective of this study was to determine whether a chemical immunomodulation protocol could reduce the resistance of NOD/LtSz-SCID mice to Plasmodium falciparum infection and provide an improved mouse model for screening the antimalarial activity of new compounds. This model was compared with the presently used immunodeficient Beige/Nude/Xid (BNX) mouse model, using the same protocol, in terms of percentage of infected mice, parasite development, leukocyte response and phagocytosis of P. falciparum infected cells in various organs. Our results show that the combination of the chemical immune modulation protocol with the genetic background of NOD/LtSz-SCID mice results in the development of long-lasting P. falciparum infection in a high percentage of mice. A comparison of the results obtained in the histological study for both mouse models suggests that the higher rate of success in NOD/LtSz-SCID mice could be related to the reduced macrophage recruitment developed in different tissues to remove the parasite from blood.     

Involvement of clusterin and the aggresome in abnormal protein deposits in myofibrillar myopathies and inclusion body myositis

Myofibrillar myopathies (MM) are characterized morphologically by the presence of non-hyaline structures corresponding to foci of dissolution of myofibrils, and hyaline lesions composed of aggregates of compacted and degraded myofibrillar elements. Inclusion body myositis (IBM) is characterized by the presence of rimmed vacuoles, eosinophilic inclusions in the cytoplasm, rare intranuclear inclusions, and by the accumulation of several abnormal proteins. Recent studies have demonstrated impaired proteasomal expression and activity in MM and IBM, thus accounting, in part, for the abnormal protein accumulation in these diseases. The present study examines other factors involved in protein aggregation in MM and IBM. Clusterin is a multiple-function protein which participates in Abeta-amyloid, PrP(res) and a-synuclein aggregation in Alzheimer disease, prionopathies and a-synucleinopathies, respectively. gamma-Tubulin is present in the centrosome and is an intracellular marker of the aggresome. Moderate or strong clusterin immunoreactivity has been found in association with abnormal protein deposits, as revealed by immunohistochemistry, single and double-labeling immunofluorescence and confocal microscopy, in MM and IBM, and in target structures in denervation atrophy. Gamma-Tubulin has also been observed in association with abnormal protein deposits in MM, IBM, and in target fibers in denervation atrophy. These morphological findings are accompanied by increased expression of clusterin and gamma-tubulin in muscle homogenates of MM and IBM cases, as revealed by gel electrophoresis and Western blots. Together, these observations demonstrate involvement of clusterin in protein aggregates, and increased expression of aggresome markers in association with abnormal protein inclusions in MM and IBM and in targets, as crucial events related to the pathogenesis of abnormal protein accumulation and degradation in these muscular diseases.