Uptake and retention of amitriptyline by kaolinite.

As the most commonly prescribed tricyclic antidepressant, amitriptyline (AT) is frequently detected in wastewater, surface runoff, and effluents from sewage treatment plants, and could potentially reach agriculture land through the application of municipal biosolids or reclaimed water. Kaolinite is one of the most important soil components under warm and humid climate conditions. In this study, the uptake and retention of AT by kaolinite from aqueous solution were investigated by batch tests, XRD, and FTIR analyses. The uptake of AT on kaolinite was instantaneous, attributed to surface adsorption as confirmed by XRD analyses. Quantitative correlation between desorption of exchangeable cations and AT adsorption confirmed experimentally that cation exchange was the dominant mechanism of AT uptake on kaolinite. The values for free energy of adsorption also suggested physi-sorption such as cation exchange. Solution pH had minimal influence at pH 5-11 even though the pKa value of AT was 9.4 and the surface charge of kaolinite was pH-dependent.

Sentinel lymph node mapping of invasive urinary bladder cancer in animal models using invisible light.

OBJECTIVES: With conventional methodology, sentinel lymph node (SLN) mapping of invasive urinary bladder cancer is technically challenging. This study was performed to determine the utility of invisible, near-infrared fluorescent (NIRF) light for patient-specific SLN mapping, in real time under complete image guidance. METHODS: Lymphatic tracers, injection volume, NIRF excitation fluence rate, light collection of emitted fluorescence, and degree of bladder distension were systematically optimized in normal dogs and pigs. SLN mapping was then performed in pet dogs with naturally occurring invasive transitional cell carcinoma (InvTCC) of the urinary bladder, which closely mimics the human disease. RESULTS: NIRF albumin (hydrodynamic diameter [HD], 7.4 nm) and NIRF quantum dots (15-20 nm HD) injected into the bladder wall resulted in identification of draining lymph nodes (LNs) in under 3 min. In both species, considerable variability in the lymphatic drainage was observed among individuals. Optimal SLN mapping was achieved with the use of superficial, serosal injection of NIRF tracer, with the bladder distended to an intraluminal pressure of 20-40 cm H(2)O. In dogs with InvTCC, NIRF tracers identified SLNs that were confirmed histologically to harbor metastases. CONCLUSIONS: The use of invisible NIRF light permits real-time, patient-specific identification of SLNs that drain bladder cancer. Intraluminal bladder pressure is a key parameter that needs to be controlled for optimal results.