ABSTRACT
Platypnea-orthodeoxia syndrome is a rare cause of positional hypoxemia and dyspnea. We present the case of a 54-year-old man with right-to-left shunting through a patent foramen ovale in the setting of metastatic cholangiocarcinoma resulting in platypnea-orthodeoxia syndrome. The shunt was originally not visualized on cardiac magnetic resonance imaging but later detected with transesophageal echocardiography. This case highlights the importance of complimentary multimodality cardiac imaging in the diagnosis of both common and uncommon disorders.
Subject(s)
Bile Duct Neoplasms , Cholangiocarcinoma , Foramen Ovale, Patent , Male , Humans , Middle Aged , Platypnea Orthodeoxia Syndrome , Posture , Foramen Ovale, Patent/diagnosis , Foramen Ovale, Patent/diagnostic imaging , Echocardiography, Transesophageal/adverse effects , Dyspnea/etiology , Dyspnea/complications , Hypoxia/diagnosis , Hypoxia/etiology , Cholangiocarcinoma/complications , Cholangiocarcinoma/diagnosis , Bile Duct Neoplasms/complications , Bile Duct Neoplasms/diagnosis , Bile Ducts, IntrahepaticABSTRACT
Amyloid-beta (Aß) deposition occurs in the early stages of Alzheimer's disease (AD), but the early detection of Aß is a persistent challenge. Herein, we engineered a near-infrared optical nanosensor capable of detecting Aß intracellularly in live cells and intracranially in vivo. The sensor is composed of single-walled carbon nanotubes functionalized with Aß wherein Aß-Aß interactions drive the response. We found that the Aß nanosensors selectively responded to Aß via solvatochromic modulation of the near-infrared emission of the nanotube. The sensor tracked Aß accumulation in live cells and, upon intracranial administration in a genetic model of AD, signaled distinct responses in aged mice. This technology enables the interrogation of molecular mechanisms underlying Aß neurotoxicity in the development of AD in living systems.
