[Functional aspects of topographic differentiation in the peritoneum]

Volumetric measurements have been performed in vitro to define permeability for water of different parts of peritoneum. The experiments were carried out on isolated fragments of rabbit mesentery, anterior abdominal wall, and diaphragm; mesothelial layer lining these membranes was retained in one group, whereas in another one it was intentionally desquamated. The membranes were mounted between two semichambers filled with Hanks solution; the volume on both sides of the membrane was strictly controlled by photo-gauges coupled with microdosi-meters. Transmembrane volume flow (Jv; nL/sec cm2) induced by hydrostatic pressure gradient (delta P; atm) was measured using an electronic device connected with the photo-gauges, and joined with a computer which monitored the values throughout the experiment. Hydraulic conductivity (Lp; in cm/sec atm) and index of impediment (Zp; in sec atm/cm) were calculated from the monitored values. Significant differences between the three types of peritoneal membrane were observed: the hydraulic conductivity of diaphragm was lowest, and the impediment highest (0.86 +/- 0.11 x 10(-2) and 116.3 +/- 12.2, respectively) contrasting with the corresponding values of mesentery which were highest, and lowest (38.9 +/- 3.7 x 10(-2), and 2.57 +/- 0.25, resp.); peritoneum taken from anterior abdominal wall showed intermediate values (6.3 +/- 0.56 x 10(-2), and 15.9 +/- 1.5, resp.). Removal of mesothelium induced significant increase of the permeability of diaphragm and anterior abdominal wall, however, no such effect was observed in mesentery. The obtained results seem to show that various parts of peritoneum may function qualitatively different during dialysis, however, any conclusion concerning clinical aspects of the dialysis should be drawn with all proper reserves.