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Hepatic artery of dogs was embolized with cisplatin (CDDP) albumin microspheres containing chitin and chitosan to investigate the in vivo CDDP release kinetics from CDDP albumin microspheres, the CDDP cumulative characteristics in the liver, and the influence of microsphere administration on hepatic tissue. Results showed that changes in blood CDDP content were dependent on CDDP albumin microsphere type and that release kinetics were better sustained when chitin was added to the microspheres or when the microspheres were treated with chitosan. In particular, the administration of CDDP in the chitin-containing CDDP chitosan albumin microspheres showed a blood CDDP content of approximately 0.26 micrograms Pt/ml 14 d after administration. The administration of chitin-containing or chitosan treated CDDP microspheres showed a CDDP content in the hepatic tissue of 0.14 to 0.23 micrograms Pt/g 28 d after administration. They also showed better control of CDDP release than those without chitin or chitosan treatment. No CDDP influence on hepatic tissue was observed. We conclude that, even in vivo, chitin and chitosan are effective embolic materials.

Japanese monkey has a common ampullary channel. By a continuous injection of sterile saline (1 mL/min) into the pancreatic main duct, the pancreatic main ductal pressure increased from 8.4 +/- 1.0 (mean +/- SD) to a plateau level (16-25 mmHg) in 5 Japanese monkeys. The frequency and amplitude of the slow wave in electromyography of the sphincter of Oddi (SO) were significantly decreased from 14 to 2/min and 0.06 to 0.04 mV (p less than 0.01), and the frequency of the spike component significantly decreased from 53 to 14/min (p less than 0.05). As soon as infusion of saline ceased, the electromyography recovered to the original level. The mean value of the minimum loading pressure affecting myoelectrical activities of the SO was 19.8 +/- 3.0 mmHg. When the pancreatic duct was obstructed at the head, there was no significant change in the SO myoelectrographic activities in spite of increased pancreatic ductal pressure by infusion. These findings suggest that a homeostatic mechanism of pancreatic ductal pressure exists when the activity of the SO is regulated by the distending pressure in the pancreatic ductal system. This reflex regulation seemed to be mediated by the distension of the ampullary duct itself.