Mitochondria associated ER membranes and cerebral ischemia: Molecular mechanisms and therapeutic strategies.

Endoplasmic reticulum (ER) and mitochondria are two important organelles that are highly dynamic in mammalian cells. The physical connection between them is mitochondria associated ER membranes (MAM). In recent years, studies on endoplasmic reticulum and mitochondria have shifted from independent division to association and comparison, especially MAM has gradually become a research hotspot. MAM connects the two organelles, not only to maintain their independent structure and function, but also to promote metabolism and signal transduction between them. This paper reviews the morphological structure and protein localization of MAM, and briefly analyzes the functions of MAM in regulating Ca2+ transport, lipid synthesis, mitochondrial fusion and fission, endoplasmic reticulum stress and oxidative stress, autophagy and inflammation. Since ER stress and mitochondrial dysfunction are important pathological events in neurological diseases including ischemic stroke, MAM is likely to play an important role in cerebral ischemia by regulating the signaling of the two organelles and the crosstalk of the two pathological events.

Nasal metastases from neuroblastoma-a rare entity: Two case reports.

BACKGROUND: Neuroblastoma (NB) is one of the most common malignancies in children. Metastasis in NB is not uncommon. However, nasal metastases are rare. Here, we reported two pediatric cases of nasal metastases. CASE SUMMARY: Case 1 was a 3-year-old boy without a history of NB. Case 2 was a 10-year-old girl who had a history of NB for 6 years. Both of them presented with symptoms of nasal and sinus masses such as epistaxis or discharge from the nose. The radiologic imaging results revealed masses in the nasal cavity or nasopharynx in both cases and a mass in the right adrenal gland of case 1. The pathologic examination of biopsy samples of their nasal masses revealed "small round blue-cell tumor" along with abundant vascular fibrous septa. The tumor cells expressed synaptophysin, cluster of differentiation 56, chromogranin A, paired like homeobox protein 2B and a very high Ki67 index in both case but were negative for vimentin, desmin, leucocyte common antigen and cytokeratin. Myelocytomatosis viral related oncogene, neuroblastoma derived (MYCN) amplification was detected in both cases. Finally, the two cases were diagnosed as nasal metastases from NB based on the clinical and pathologic findings. The two patients affected by NB were > 18 mo old, the primary tumor location was adrenal gland, and they presented with multiple metastases. CONCLUSION: It is difficult to differentiate between metastatic NB in the nose and olfactory neuroblastoma in the absence of a history of NB. Paired like homeobox protein 2B can play an important role in the diagnosis and differential diagnosis of this disease.