22 research outputs found
Intrathoracic Endotracheal Metastasis from Nasopharyngeal Carcinoma: A First Case Report and Review of the Literature
Intrathoracic endotracheal metastasis from a very distant site is extremely rare. We report the first case of such a disease in a 68-year-old man with nasopharyngeal carcinoma who presented with a cough and hemoptysis 34 months after finishing radiotherapy. Prior to tracheal metastasis, he developed a solitary metastasis in the lung and underwent chemotherapy followed by radiotherapy. Computed tomography showed the presence of an enlarged lymph node in the para-aortic arch. Fiberoptic bronchoscopy revealed an endotracheal tumor 1 cm above the carina. Histological and immunohistochemical analyses confirmed its nasopharyngeal origin. He was treated with conventional radiotherapy and three-dimensional conformal radiotherapy; complete tumor remission was achieved. He died of nonmalignant disease with no signs of tumor recurrence 2 years after treatment completion. Radiotherapy may be an appropriate management approach to achieve long-term tumor control for this disease
Optical bulk-boundary dichotomy in a quantum spin Hall insulator
The bulk-boundary correspondence is a key concept in topological quantum
materials. For instance, a quantum spin Hall insulator features a bulk
insulating gap with gapless helical boundary states protected by the underlying
Z2 topology. However, the bulk-boundary dichotomy and distinction are rarely
explored in optical experiments, which can provide unique information about
topological charge carriers beyond transport and electronic spectroscopy
techniques. Here, we utilize mid-infrared absorption micro-spectroscopy and
pump-probe micro-spectroscopy to elucidate the bulk-boundary optical responses
of Bi4Br4, a recently discovered room-temperature quantum spin Hall insulator.
Benefiting from the low energy of infrared photons and the high spatial
resolution, we unambiguously resolve a strong absorption from the boundary
states while the bulk absorption is suppressed by its insulating gap. Moreover,
the boundary absorption exhibits a strong polarization anisotropy, consistent
with the one-dimensional nature of the topological boundary states. Our
infrared pump-probe microscopy further measures a substantially increased
carrier lifetime for the boundary states, which reaches one nanosecond scale.
The nanosecond lifetime is about one to two orders longer than that of most
topological materials and can be attributed to the linear dispersion nature of
the helical boundary states. Our findings demonstrate the optical bulk-boundary
dichotomy in a topological material and provide a proof-of-principal
methodology for studying topological optoelectronics.Comment: 26 pages, 4 figure
In Vivo Biodistribution of Mixed Shell Micelles with Tunable Hydrophilic/Hydrophobic Surface
The miserable targeting performance of nanocarriers for
cancer
therapy arises largely from the rapid clearance from blood circulation
and the major accumulation in the organs of the reticuloendothelial
system (RES), leading to inefficient enhanced permeability and retention
(EPR) effect after intravenous injection (i.v.). Herein, we reported
an efficient method to prolong the blood circulation of nanoparticles
and decrease their deposition in liver and spleen. In this work, we
fabricated a series of mixed shell micelles (MSMs) with approximately
the same size, charge and core composition but with varied hydrophilic/hydrophobic
ratios in the shell through spontaneously self-assembly of block copolymers
polyÂ(ethylene glycol)-<i>block</i>-polyÂ(l-lysine)
(PEG-<i>b</i>-PLys) and polyÂ(<i>N</i>-isopropylacrylamide)-<i>block</i>-polyÂ(aspartic acid) (PNIPAM-<i>b</i>-PAsp)
in aqueous medium. The effect of the surface heterogeneity on the
in vivo biodistribution was systematically investigated through in
vivo tracking of the <sup>125</sup>I-labeled MSMs determined by Gamma
counter. Compared with single PEGylated micelles, some MSMs were proved
to be significantly efficient with more than 3 times lower accumulation
in liver and spleen and about 6 times higher concentration in blood
at 1 h after i.v.. The results provide us a novel strategy for future
development of long-circulating nanocarriers for efficient cancer
therapy
Self-Regulated Multifunctional Collaboration of Targeted Nanocarriers for Enhanced Tumor Therapy
Exploring
ideal nanocarriers for drug delivery systems has encountered
unavoidable hurdles, especially the conflict between enhanced cellular
uptake and prolonged blood circulation, which have determined the
final efficacy of cancer therapy. Here, based on controlled self-assembly,
surface structure variation in response to external environment was
constructed toward overcoming the conflict. A novel micelle with mixed
shell of hydrophilic polyÂ(ethylene glycol) PEG and pH responsive hydrophobic
polyÂ(β-amino ester) (PAE) was designed through the self-assembly
of diblock amphiphilic copolymers. To avoid the accelerated clearance
from blood circulation caused by the surface exposed targeting group
cÂ(RGDfK), here cÂ(RGDfK) was conjugated to the hydrophobic PAE and
hidden in the shell of PEG at pH 7.4. At tumor pH, charge conversion
occurred, and cÂ(RGDfK) stretched out of the shell, leading to facilitated
cellular internalization according to the HepG2 cell uptake experiments.
Meanwhile, the heterogeneous surface structure endowed the micelle
with prolonged blood circulation. With the self-regulated multifunctional
collaborated properties of enhanced cellular uptake and prolonged
blood circulation, successful inhibition of tumor growth was achieved
from the demonstration in a tumor-bearing mice model. This novel nanocarrier
could be a promising candidate in future clinical experiments