Uncommon endocytic and trafficking pathway of the natural killer cell CD94/NKG2A inhibitory receptor.

The CD94/NKG2A inhibitory receptor, expressed by natural killer and T cells, is constantly exposed to its HLA-E ligand expressed by surrounding cells. Ligand exposure often induces receptor downregulation. For CD94/NKG2A, this could potentiate activation receptor(s) induced responses to normal bystander cells. We investigated CD94/NKG2A endocytosis and found that it occurs by an amiloride-sensitive, Rac1-dependent macropinocytic-like process; however, it does not require clathrin, dynamin, ADP ribosylation factor-6, phosphoinositide-3 kinase or the actin cytoskeleton. Once endocytosed, CD94/NKG2A traffics to early endosomal antigen 1(+), Rab5(+) early endosomes. It does appear in Rab4(+) early/sorting endosome, but, in the time period examined, fails to reach Rab11(+) recycling or Rab7(+) late endosomes or lysosome-associated membrane protein-1(+) lysosomes. These results indicate that CD94/NKG2A utilizes a previously undescribed endocytic mechanism coupled with an abbreviated trafficking pattern, perhaps to insure surface expression.

Limitations in improving detection of pancreatic adenocarcinoma.

OBJECTIVE: To review the current trends in pancreatic cancer research and propose alternatives for an earlier diagnosis. METHOD: A search was conducted using the PubMed and Scielo electronic databases to find statistics related to the incidence of pancreatic cancer. RESULTS: Pancreatic cancer is the fourth most common cause of cancer mortality in the USA; in Colombia the incidence of this neoplasia is 4.5 per 100,000 individuals; and in Peru, amongst digestive diseases, it is the fifth most common cause. In Brazil and Chile this cancer has increased in incidence, while in Mexico, it has decreased in terms of the relative percentage of gastrointestinal cancers from 1976 to 2003. Chronic pancreatitis, cigarette smoking, diabetes, obesity and dietary mutagen exposure are the most consistent risk factors implicated in the development of pancreatic cancer; however, the genetic and molecular changes underlying the epidemiological association between these factors and pancreatic cancer remain largely unknown, and only 5-10% are hereditary in nature. CONCLUSION: The prognosis for pancreatic cancer has not changed substantially for at least the last 20 years. The most useful tumor marker for pancreatic adenocarcinoma is still the carbohydrate antigen 19-9 (CA19-9). Currently, a multimodal-screening approach of endoscopic ultrasound, computed tomography and endoscopic retrograde cholangiopancreatography are the most effective methods to detect pancreatic cancer in high-risk patients. Future options for early detection of this malignancy are focused on new molecular markers, telomerase enzyme, receptor-targeted imaging using multifunctional nanoparticles, detection of glycan changes and epigenetics.

Cultivo experimental del cladocero Moina sp alimentado con Ankistrodesmus sp y Saccharomyces cereviseae / Experimental culture of cladocerans Moina sp feed with Ankistrodesmus sp and Saccharomyces cereviseae

Objetivo. Realizar un cultivo experimental de cladócero Moina sp alimentado con Ankistrodesmus sp y Saccharomyces cereviseae. Materiales y métodos. Fueron realizados cultivos experimentales de la cepa de cladóceros Moina sp en el laboratorio de Alimento Vivo de la Universidad de Córdoba, bajo condiciones controladas de temperatura (22oC), pH (7.6), intensidad lumínica (2000 lux) y aireación. Se emplearon dos dietas de alimento como tratamiento (Ankistrodesmus y Ankistrodesmus mas Saccharomyces cereviseae)en concentración de 40 x 105 cel.ml-1 cada uno, para determinar su efecto sobre el desempeño de la población. Diariamente se registró la densidad poblacional y celular. Resultados. Se obtuvieron diferencias significativas para el efecto de las dietas sobre el crecimiento poblacional de los cladóceros, los individuosalimentados con Ankistrodesmus sp + Saccharomyces cereviseae alcanzaron una densidad de 12.3a ±0.30 org/ml-1 presentando mayor tasa instantánea de crecimiento (K) 0.36 ± 0.002, el menor tiempo de duplicación (td) 1.94 ± 0.012 y el mayor rendimiento (r) 1,1 ± 0.07 clad.ml-1.día-1. Conclusión. Los cladóceros por sus características de crecimiento en cultivo, presentan adaptación favorable a las condiciones de manejo para la producción de biomasas potencialmente útiles como partícula nutritiva con fines acuícolas.