Merkel cell carcinoma (MCC) is a rare, but highly aggressive, malignant neuroendocrine tumor, with a higher prevalence in men, Caucasians, and the elderly. It is usually identified in photo-exposed areas such as the head, trunk, and extremities. It is related to locoregional recurrences and metastases, which conditions a high mortality rate. Currently, the pathogenesis is unclear, but it is related to ultraviolet radiation, immunosuppression, and polyomavirus infection. Prompt diagnosis and treatment are essential to improve the survival rate.

Gallstone ileus represents a complication of cholelithiasis, which in the literature has been reported as a rare cause of mechanical intestinal obstruction, however, the reported incidence is not so low, especially after 65 years of age. The formation of a bilioenteric fistula allows the passage of a large gallstone into the intestine, usually impacting the distal intestine. It is associated with a mortality that ranges between 12 and 27%. Treatment is surgical, although there is no consensus on which of the surgical techniques is the one of choice. We report the case of an 87-year-old male patient who was admitted to the emergency department with intestinal obstruction. He was diagnosed with gallstone ileus and was treated surgically with exploratory laparotomy, enterotomy with stone extraction, and primary closure. The evolution was favorable and without complications.

CommentaryThe cognitive decline in Alzheimer's disease (AD) is associated with the accumulation of neurofibrillary tangles (NFTs) [1] and neuritic plaques (NPs) [2,3]. The NFTs are formed by the accumulation of paired helical filaments (PHFs) in neuronal soma, consisting of tau protein. NPs contain extracellular amyloid-β peptide (Aβ) and dystrophic neurites (DNs) containing PHFs. The development of transgenic animals, has led to a better understanding of the abnormal processing of tau protein and amyloid-β. Oddo et al. in 2003 generated a triple transgenic mouse model (3xTg-AD), in which there is intracellular accumulation of tau protein and extracellular deposition of amyloid-β plaques [4]. The expression and aggregation of human tau protein in the 3xTg-AD mouse (aged between 3 and 28 months) were analyzed using a panel of antibodies directed against different epitopes of phosphorylated tau, amino (N-) and carboxy (C-) terminal domains, using double and triple immunostaining and confocal microscopy. Our results show there is over-expression of human tau protein in the 3xTg-AD mouse from three months of age in the *Corresponding author: José Luna-Muñoz, Brain Bank-LaNSE of CINVESTAV-IPN,

Hemos usado una variedad de marcadores inmunológicos combinados con el colorante rojo tiazina (RT), un marcador específico para diferenciar el estado fibrilar del no fibrilar del amiloide-β y tau en la enfermedad de Alzheimer. En este estudio hemos usado el RT como un marcador potencial de diagnóstico en la EA en tejido cerebral sin fijar en una impronta. En los experimentos control se incluia el uso de la tinción con el colorante tioflavina-S, tejido fijado y alguna doble tinción de este material con el RT. Se seleccionaron los marcadores para la proteína tau TaC-3 y 423. El analisis hecho indican que el RT mantiene una fuerte afinidad para las marañas neurofibrilares y placas neuríticas en corteza temporal de tejido sin fijar y congelado, este se descongelo previa la realización de la impronta. Esto indica que el TR es una herramienta potencial para un rápido diagnóstico posmortem de la neuropatología de la EA. La fijación no necesariamente es requerida para la inmunorreactividad de tau en los cortes histológicos.

Hemos usado una variedad de marcadores inmunológicos combinados con el colorante rojo tiazina (RT), un marcador específico para diferenciar el estado fibrilar del no fibrilar del amiloide-β y tau en la enfermedad de Alzheimer. En este estudio hemos usado el RT como un marcador potencial de diagnóstico en la EA en tejido cerebral sin fijar en una impronta. En los experimentos control se incluia el uso de la tinción con el colorante tioflavina-S, tejido fijado y alguna doble tinción de este material con el RT. Se seleccionaron los marcadores para la proteína tau TaC-3 y 423. El analisis hecho indican que el RT mantiene una fuerte afinidad para las marañas neurofibrilares y placas neuríticas en corteza temporal de tejido sin fijar y congelado, este se descongelo previa la realización de la impronta. Esto indica que el TR es una herramienta potencial para un rápido diagnóstico posmortem de la neuropatología de la EA. La fijación no necesariamente es requerida para la inmunorreactividad de tau en los cortes histológicos.