Gadolinium-chitosan nanoparticles as a novel contrast agent for potential use in clinical bowel-targeted MRI: a feasibility study in healthy rats.

BACKGROUND: MRI is of increasing importance in the diagnostic evaluation of gastrointestinal diseases, with depiction of mucosal enhancement obtained with conventional intravenous contrast. Routine clinical use of contrast agents has been carried out using intravenous injection for mucosal imaging. Contrast agents that specifically target the intestinal mucosa are therefore needed to improve clinical imaging of the mucosal surface. PURPOSE: To synthesize a novel contrast agent for gadopentetic acid (Gd-DTPA)-loaded chitosan nanoparticles and observe the absorption of the nanoparticles in the colon wall of healthy rats by MR imaging in vivo. MATERIAL AND METHODS: A contrast agent was successfully synthesized by a modified emulsion coalescence method, and the resulting agents were characterized in detail by dynamic light-scattering spectroscopy and inductively coupled plasma emission spectroscopy. The cytotoxicity of Gd-chitosan nanoparticles was evaluated by an MTT assay. Gadolinium-chitosan (Gd@chitosan) nanoparticles were administered to the colon mucosa of healthy rats by rectal administration, and MRI scans in vivo were carried out with a 3.0 T imaging scanner at various time points. RESULTS: The prepared Gd@chitosan nanoparticles were ~420 nm in diameter with a 74.4% Gd-DTPA content. The MTT assay indicated little cytotoxicity. MRI results showed that nanoparticles can be retained in both the stratum submucosum and epithelial cells of the colon for almost 80 min. Transmission electron microscopy images further revealed that Gd@chitosan nanoparticles were localized inside the mucosal cells or intercellular space, while tissue from Gd-DTPA aqueous solution administration showed nothing. Due to the infusion of Gd@chitosan nanoparticles, the MR signal intensity of colon mucosa increased from about 6% to 35%, and the contrast enhancement was highest at 20 min after administration. CONCLUSION: Gd@chitosan nanoparticles with high Gd-DTPA content were successfully prepared for use as a novel MRI contrast agent. All results indicated that rectally administered Gd@chitosan nanoparticles have the potential for MRI diagnosis of colon mucosal disease.

In situ growth of heterostructured Sn/SnO nanospheres embedded in crumpled graphene as an anode material for lithium ion batteries.

The in situ growth of Sn/SnO heterostructured nanospheres embedded in crumpled graphene is based on a new strategy for the calcination of tin oleate coating on the crystal surface of sodium carbonate. Sn/SnO nanospheres and crumpled graphene are acquired simultaneously without external forces involved. The obtained composite exhibits superior electrochemical properties when used as an anode material for lithium-ion batteries.

Uniportal video-assisted thoracoscopic combined segmentectomy for lung cancer with incomplete fissure.

This video clip demonstrated a performance of uniportal video-assisted thoracoscopic surgery combined segmentectomy. The patient had a potential invasive nodule located near the bifurcation of right bronchus, 3-dimensional reconstruction image showed the fissure between posterior segment of upper lobe and superior segment of lower lobe was incomplete. An up-to-down approach was applied in this operation with the en bloc resection of the two segments. Pathological report was adenocarcinoma with negative margin (TNM stage: T1aN0M0).

Primary tracheal schwannoma treated by surgical resection: a case report.

The rarity and non-specific symptoms of benign primary tracheal tumors always leaded to misdiagnosis and delayed treatment, and also undefined the optimal treatment. In this case, a 45-year-old woman had a history of progressive shortness of breath and dry cough for several years, CT scan revealed an intra-luminal tracheal mass invaded the left side of tracheal wall. After being located by bronchoscope preoperatively, the tumor was removed by surgical resection. The tumor was 1.5 cm in diameter with intact capsule. The pathological result confirmed the diagnosis of schwannoma.