Decreasing dissolved oxygen enhances in situ curtailment of intermediate Cr(VI) during photo-oxidative decomplexation of Cr(III)-EDTA.

Cr(III)-organic complexes are stably presented in tanning, electroplating, and other industrial wastewaters, and their safe and efficient removal remains a current challenge. Available oxidation processes can remove Cr(III) complexes but readily result in highly toxic Cr(VI) accumulation. Herein, negligible Cr(VI) accumulation was achieved during photo-oxidation of Cr(III) complexes using a simple strategy of decreasing dissolved oxygen (DO). At the DO concentration of 5.0 mg·L-1 or less, the in-process formation of intermediate Cr(VI) was totally abated by in situ formed reductive species, and total Cr was reduced from 9.0-11.0 mg·L-1 to below 1.0 mg·L-1. A complete curtailment of Cr(VI) was observed after 30-60 min at pH 6.0-9.0. Increasing Cr(III)-EDTA concentration and decreasing pH value facilitated the in situ reduction of intermediate Cr(VI). Based on the identification of intermediates and additional Cr(II) and quenching experiments, the possible key species involved in intermediate Cr(VI) reduction were the photogenerated Cr(II) and some C-centered radicals from Cr(III)-EDTA decomplexation, and the possible mechanisms of Cr(III)-EDTA decomplexation and intermediate Cr(VI) reduction were thus proposed. The process also showed efficient treatment on other Cr(III) complexes (citrate, oxalate, and tartrate) and realistic Cr(III) complexed wastewater. This study would provide an insignificant Cr(VI)-accumulated alternative for efficient and safe removal of Cr(III) complexes from contaminated water.

Early detection of carcinoma in situ of the bladder: a comparative study of white light cystoscopy, narrow band imaging, 5-ALA fluorescence cystoscopy and 3-dimensional optical coherence tomography.

PURPOSE: We compared the efficacy and potential limitations of white light cystoscopy, narrow band imaging, 5-ALA fluorescence cystoscopy and 3-dimensional optical coherence tomography for early diagnosis of bladder carcinoma in situ. MATERIALS AND METHODS: By expressing simian virus 40T antigen in the urothelium carcinoma in situ typically develops in SV40T transgenic mice in about 8 to 20 weeks and then frank high grade papillary urothelial carcinoma starts to emerge. A total of 18 control and 29 SV40T mice were examined during weeks 8 to 22 by white light cystoscopy, fluorescence cystoscopy, narrow band imaging and 3-dimensional optical coherence tomography. Results were validated by histology. Newly improved algorithms for computer aided detection were applied to acquired 3-dimensional optical coherence tomography images to enhance the quantitative diagnosis of carcinoma in situ in near real time. RESULTS: Of 29 carcinoma in situ samples 27 were detected by 3-dimensional optical coherence tomography, 1 by white light cystoscopy, 26 by narrow band imaging and 13 by fluorescence cystoscopy. Of the 18 histologically confirmed benign cases 17 were detected by 3-dimensional optical coherence tomography, 14 by white light cystoscopy, 5 by narrow band imaging and 18 by fluorescence cystoscopy. The diagnostic sensitivity of white light cystoscopy (3.4%) and fluorescence cystoscopy (44.8%), and the specificity of narrow band imaging (27.8%) were significantly enhanced by 3-dimensional optical coherence tomography to 93.1% and 94.4%, respectively (p <0.01). CONCLUSIONS: Three-dimensional optical coherence tomography with quantitative computer aided detection can significantly enhance the sensitivity of white light cystoscopy and fluorescence cystoscopy, and the specificity of narrow band imaging for early diagnosis of carcinoma in situ. This suggests the potential of narrow band imaging guided 3-dimensional optical coherence tomography for future clinical detection of carcinoma in situ when effective image guidance is desirable.

High-resolution imaging diagnosis and staging of bladder cancer: comparison between optical coherence tomography and high-frequency ultrasound.

A comparative study between 1.3-microm optical coherence tomography (OCT) and 40-MHz high-frequency ultrasound (HFUS) is presented to enhance imaging of bladder cancers ex vivo. A standard rat bladder cancer model in which transitional cell carcinoma (TCC) was induced by intravesical instillation of AY-27 cells was followed independently with both OCT and HFUS, and the image identifications were compared to histological confirmations. Results indicate that both OCT and HFUS were able to delineate the morphology of rat bladder [e.g., the urothelium (low backscattering/echo) and the underlying lamina propria and muscularis (high backscattering/echo]. OCT differentiated inflammatory lesions (e.g., edema, infiltrates and vasodilatation in lamina propria, hyperplasia) and TCC based on characterization of urothelial thickening and enhanced backscattering or heterogeneity (e.g., papillary features), which HFUS failed due to insufficient image resolution and contrast. On the other hand, HFUS was able to stage large T2 tumors that OCT failed due to limited imaging depth. The results suggest that multimodality cystoscopy combining OCT and HFUS may have the potential to enhance the diagnosis and staging of bladder cancers and to guide tumor resection, in which both high resolution (approximately 10 microm) and enhanced penetration (> 3mm) are desirable.

Lessons learned from the endovascular treatment of abdominal aortic aneurysm and a preliminary experience of our center.

BACKGROUND: The development of technical approaches for endovascular abdominal aortic aneurysm (AAA) repair during the last decade was briefly reviewed. The role of endovascular AAA repair as a new reliable method of treatment in high-risk patients was evaluated in both the major studies reported and a preliminary result of our center. METHODS: General criteria for the selection and exclusion of high-risk patients were summarized. Six patients (mean age: 72 years) with complex infrarenal AAA underwent endovascular aneurysm repair using the bifurcated stent graft system. Routine follow-up examination included computed tomography performed periodically from the post-operative month up to one year. Patients suspected of endoleak underwent angiography and further endovascular treatment. RESULTS: Successful deployment of the endograft and exclusion of the aneurysm was achieved in all six patients (100%) in our preliminary series. None of our patients required conversion to open aneurysmal repair. Comorbidity was an important factor in the outcome of aneurysm repair in high-risk patients, with cardiovascular disease and chronic obstructive pulmonary disease being the major comorbid conditions. Cardiac events were the most common complications, followed by transient renal failure, wound infection and endoleaks, which were corrected with endovascular treatment. CONCLUSIONS: The long-term results and efficacy of endovascular repair of infrarenal AAA remain to be demonstrated, but the procedure is believed to provide a safe and effective alternative treatment for high-risk patients suffering from AAA.