In this study, we determined the effect of 80% deacetylated chitin (DAC-80) membrane on postsurgical bleeding after visceral and parietal peritoneal abrasion. Japanese white rabbits underwent a midline laparotomy followed either by a bilateral peritoneal sidewall abrasion (4 x 4 cm) or an abrasion of liver surface (3 x 2 cm). The injured surface was then covered with a 0.2 mm thick DAC-80 membrane. On postsurgical day 2, the rabbits were sacrificed and the amounts of postsurgical bleeding was determined by quantitating the number of red blood cells recovered in 50 ml peritoneal lavage fluid. The DAC-80 membrane was found to reduce postsurgical bleeding after the abrasion of liver surface (treated with DAC-80 membrane: 2.9 +/- 0.8; control: 24.6 +/- 5.9 x 10(8) cells/peritoneal cavity, P less than 0.005). This same hemostatic activity was not observed after application in the peritoneal sidewall abrasion model. We also measured plasminogen activator activity (PA) and urokinase inhibitory (PAI) activity in the spent culture media of macrophages recovered from the postsurgical peritoneal exudate. The DAC-80 membrane reduced the PA secretion from postsurgical macrophages after liver surface abrasion (treated with DAC-80: 2.8 +/- 0.7; control: 3.9 +/- 0.9 mPU/ml). The DAC-80 membrane also showed similar effects on PA secretion after peritoneal sidewall abrasion. No significant effects were found in the secretion of PAI by postsurgical macrophages in both surgical models. These findings suggest that the DAC-80 membrane may have hemostatic activity through the modulation of fibrinolytic activity of peritoneal exudative macrophages.
ABSTRACT. The ecology of the pea crab Pinnixa tumida living in the endobenthic holothurian Paracaudina chllensis, which buries its body in the fine sandy bottom in the sublittoral zone, was investigated. Almost all of the pea crabs collected from the11 host holothurians were mature females. Mature pea crabs were found to live singly in the alimentary canal of the larger hosts, which are ma~nly dlstributed just below the low water level of the spring tlde. However, immature crabs were not found In either large or small hosts. In the laboratory, mature crabs searched for the tip of the host's tail, which appeared on the sand's surface, and then entered the host's alimentary canal through the opening of the anus at the tail's tip. These results indicate that the pea crab enters larger hosts only when it is mature, or just before maturity. Pea crabs showed 2 types of feeding preference in the laboratory: suspended particles and the mucus secreted In the alimentary canal of the host. Ovigerous females were found in the hosts between late February and mid-May, carrying eggs which developed slo~vly and synchronously with those of almost all of the other ovigerous females observed throughout this period, indicating that the pea crab has an annual breeding cycle. The biology of the pea crab was compared with that of crabs living in bivalves and on irregular echinoids.
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