Gold Nanoparticles Enhancing Generation of ROS for Cs-137 Radiotherapy.

Radiotherapy is an important modality for the treatment of cancer, e.g., X-ray, Cs-137 γ-ray (peak energy: 662 keV). An important therapy pathway of radiation is to generate the double strand breaks of DNA to prohibit the proliferation of cancer cells. In addition, the excessive amount of reactive oxygen species (ROS) is induced to damage the organelles, which can cause cellular apoptosis or necrosis. Gold nanoparticles (GNPs) have been proven potential as a radiosensitizer due to the high biocompatibility, the low cytotoxicity and the high-Z property (Z = 79) of gold. The latter property may allow GNPs to induce more secondary electrons for generating ROS in cells as irradiated by high-energy photons. In this paper, the radiobiological effects on A431 cells with uptake of 55-nm GNPs were studied to investigate the GNPs-enhanced production of ROS on these cells as irradiated by Cs-137 γ-ray. The fluorescence-labeling image of laser scanning confocal microscopy (LSCM) shows the excessive expression of ROS in these GNPs-uptake cells after irradiation. And then, the follow-up disruption of cytoskeletons and dysfunction of mitochondria caused by the induced ROS are observed. From the curves of cell survival fraction versus the radiation dose, the radiosensitization enhancement factor of GNPs is 1.29 at a survival fraction of 30%. This demonstrates that the tumoricidal efficacy of Cs-137 radiation can be significantly raised by GNPs. Because of facilitating the production of excessive ROS to damage tumor cells, GNPs are proven to be a prospective radiosensitizer for radiotherapy, particularly for the treatment of certain radioresistant tumor cells. Through this pathway, the tumoricidal efficacy of radiotherapy can be raised.

Water-Immersion Laser-Scanning Annealing for Improving Polycrystalline Au Films.

A water-immersion laser-scanning annealing (WILSA) method was developed for the heat treatment of a deposited polycrystalline Au film on a glass. The material characterization using X-ray diffraction, field-emission scanning electron microscopy, and electron backscatter diffraction shows improved crystallinity with a more uniform crystallographic orientation of (111) and the grain growth of the annealed Au film. Additionally, the optical constants of the Au film before and after annealing were characterized by spectroscopic ellipsometry in the visible to near-infrared (NIR) regime, and the corresponding optical densities (ODs) were measured by transmittance spectroscopy. Our results show that the extinction coefficient and the OD of the annealed film are significantly reduced, particularly in the NIR regime. This is because the grain growth caused by the annealing reduces the density of grain boundaries, leading to the decrease of the loss of free electrons' scattering at grain boundaries. Hence, the damping effect of the surface plasmon is reduced. Additionally, the integrity of the WILSA-treated thin film is kept intact without pinholes, usually produced by the conventional thermal annealing. Based on the improved optical property of the WILSA-treated Au film, two performances of an insulator-metal-insulator (IMI) layered structure of biosensors are theoretically analyzed. Numerical results show that the propagation length of a long-range surface plasmon polariton along an IMI structure with an annealed Au film is significantly increased, compared to an unannealed film, particular in the NIR region. For the other application of using an IMI sensor to detect the shift of the surface-plasmon-resonance dip in the total internal reflection spectrum for the measurement of a change of the medium's refractive index, the sensitivity is also profoundly improved by the WILSA method. It is worth mentioning that the optimal heating conditions (laser wavelength, fluence, exposure time, and scanning step) depend on the thickness of the Au film. Our study provides a postprocess of WILSA to improve the optical properties of a deposited polycrystalline Au film for raising the sensitivity of the related biosensors.

Laser-Induced Plasmonic Nanobubbles and Microbubbles in Gold Nanorod Colloidal Solution.

In this work, we studied the initiated plasmonic nanobubbles and the follow-up microbubble in gold nanorod (GNR) colloidal solution induced by a pulsed laser. Owing to the surface plasmon resonance (SPR)-enhanced photothermal effect of GNR, several nanobubbles are initiated at the beginning of illumination and then to trigger the optical breakdown of water at the focal spot of a laser beam. Consequently, microbubble generation is facilitated; the threshold of pulsed laser energy is significantly reduced for the generation of microbubbles in water with the aid of GNRs. We used a probing He-Ne laser with a photodetector and an ultrasonic transducer to measure and investigate the dynamic formations of nanobubbles and the follow-up microbubble in GNR colloids. Two wavelengths (700 nm and 980 nm) of pulsed laser beams are used to irradiate two kinds of dilute GNR colloids with different longitudinal SPRs (718 nm and 966 nm). By characterizing the optical and photoacoustic signals, three types of microbubbles are identified: a single microbubble, a coalesced microbubble of multiple microbubbles, and a splitting microbubble. The former is caused by a single breakdown, whereas the latter two are caused by discrete and series-connected multiple breakdowns, respectively. We found that the thresholds of pulsed energy to induce different types of microbubbles are reduced as the concentration of GNRs increases, particularly when the wavelength of the laser is in the near-infrared (NIR) region and close to the SPR of GNRs. This advantage of a dilute GNR colloid facilitating the laser-induced microbubble in the NIR range of the bio-optical window could make biomedical applications available. Our study may provide an insight into the relationship between plasmonic nanobubbles and the triggered microbubbles.

Single-Crystalline Gold Nanowires Synthesized from Light-Driven Oriented Attachment and Plasmon-Mediated Self-Assembly of Gold Nanorods or Nanoparticles.

Through the light-driven geometrically oriented attachment (OA) and self-assembly of Au nanorods (NRs) or nanoparticles (NPs), single-crystalline Au nanowires (NWs) were synthesized by the irradiation of a linearly-polarized (LP) laser. The process was conducted in a droplet of Au colloid on a glass irradiated by LP near-infrared (e.g. 1064 nm and 785 nm) laser beam of low power at room temperature and atmospheric pressure, without any additive. The FE-SEM images show that the cross sections of NWs are various: tetragonal, pentagonal or hexagonal. The EDS spectrum verifies the composition is Au, and the pattern of X-ray diffraction identifies the crystallinity of NWs with the facets of {111}, {200}, {220} and {311}. We proposed a hypothesis for the mechanism that the primary building units are aligned and coalesced by the plasmon-mediated optical torque and force to form the secondary building units. Subsequently, the secondary building units undergo the next self-assembly, and so forth the tertiary ones. The LP light guides the translational and rotational motions of these building units to perform geometrically OA in the side-by-side, end-to-end and T-shaped manners. Consequently, micron-sized ordered mesocrystals are produced. Additionally, the concomitant plasmonic heating causes the annealing for recrystallizing the mesocrystals in water.

Perineural invasion and expression of nerve growth factor can predict the progression and prognosis of oral tongue squamous cell carcinoma.

BACKGROUND: Perineural invasion (PNI) and nerve growth factor (NGF) expression are found to be significantly associated with the progression and/or prognosis of several human cancers. METHODS: Immunohistochemical staining for S-100 and NGF proteins was performed to assess the PNI and NGF expression level in 116 oral tongue squamous cell carcinoma (OTSCC) specimens, respectively. RESULTS: The PNI rate increased from 22% of the original pathological report, through 39% after reevaluation of hematoxylin and eosin-stained tissue sections, to 51% with the help of anti-S-100 immunostaining. The positive PNI was significantly associated with larger tumor size (P = 0.033), positive lymph node metastasis (P = 0.001), advanced clinical stage (P < 0.001), greater tumor thickness (P < 0.001), close or positive section margin (P = 0.013), and higher grade of cancer invasion front pattern (P < 0.001). Moreover, the high NGF expression level was significantly correlated with larger tumor size (P = 0.009), positive lymph node metastasis (P = 0.004), advanced clinical stage (P < 0.001), greater tumor thickness (P = 0.005), close or positive section margin (P = 0.030), and the positive PNI (P = 0.009). In addition, OTSCC patients with positive PNI or high NGF expression level had significantly worse overall survival than those with negative PNI or low NGF expression level, respectively. CONCLUSIONS: Anti-S-100 immunostaining is an effective technique to detect occult PNI. Both the positive PNI and NGF expression level are valuable biomarkers that can predict the progression of OTSCC and prognosis of OTSCC patients.

Increased expression of MCM5 is significantly associated with aggressive progression and poor prognosis of oral squamous cell carcinoma.

BACKGROUND: Overexpression of MCM5 protein has been found to be significantly associated with the progression and prognosis of several human cancers. METHODS: This study used immunohistochemistry to examine the expression of MCM5 protein in 97 specimens of oral squamous cell carcinomas (OSCC), 80 specimens of oral epithelial dysplasia (OED, including 31 mild, 29 moderate, and 20 severe OED samples), and 20 specimens of normal oral mucosa (NOM). RESULTS: We found that the mean nuclear MCM5 labeling indices (LIs) increased significantly from NOM (15 ± 6%), through mild (25 ± 10%), moderate (34 ± 9%), and severe OED (43 ± 12%), to OSCC samples (61 ± 16%, P < 0.001). A significant correlation was found between the higher mean nuclear MCM5 LI and OSCCs with site at the tongue (P = 0.046), larger tumor size (P = 0.032), positive lymph node metastasis (P = 0.003), more advanced clinical stage (P = 0.002), higher histological grade (P = 0.002), deeper invasion depth (P = 0.0001), and perineural invasion (P = 0.0047). Only nuclear MCM5 LI â‰§ 60% was identified as independent unfavorable prognostic factor by multivariate regression analyses (P = 0.049). The Kaplan-Meier curve showed that patients with OSCC with a nuclear MCM5 LI â‰§ 60% had a significantly poorer cumulative survival than those with a nuclear MCM5 LI < 60% (log-rank test, P = 0.0062). CONCLUSIONS: The increased expression of MCM5 protein begins at the oral pre-cancerous stage. The higher expression of MCM5 protein is significantly associated with the aggressive progression and poor prognosis of OSCC.

Meta-analysis on reconstructions of posterior mediastinal route and anterior mediastinal route after esophagectomy / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy and safety of posterior mediastinal route (PR) as compared with anterior mediastinal route (AR) after esophagectomy.</p><p><b>METHODS</b>A systematic literature retrieval was carried out to obtain studies of randomized controlled trials (RCT) comparing PR with AR after esophagectomy before June 2012. Study selection, data collections and methodological quality assessments of retrieved studies were independently performed by two individual reviewers and meta-analysis was conducted using the RevMan 5.0 software.</p><p><b>RESULTS</b>Six RCTs involving 376 patients (PR:197 cases, AR:179 cases) met the selection criteria. Meta-analysis showed that operative mortality (RR=0.49, 95%CI:0.18-1.36), anastomotic leaks (RR=0.95, 95%CI:0.44-2.07), cardiac morbidity (RR=0.51, 95%CI:0.25-1.04), pulmonary morbidity (RR=0.69, 95%CI:0.41-1.15), anastomotic strictures (RR=0.88, 95%CI:0.62-1.25), dysphagia (RR=1.26, 95%CI:0.75-2.11), 6-month body weight after esophagectomy were not significantly different between these two routes of reconstruction (all P>0.05).</p><p><b>CONCLUSION</b>AR should be the choice of reconstruction in view of its potential advantages in the prevention of tumor recurrence within the gastric conduit and avoidance of conduit irradiation when undergoing postoperative radiotherapy. However, further studies are needed to confirm the difference of long-term efficacy between the two routes.</p>