8 research outputs found
A mathematical model for fluid-glucose-albumin transport in peritoneal dialysis
A mathematical model for fluid and solute transport in peritoneal dialysis is
constructed. The model is based on a three-component nonlinear system of
two-dimensional partial differential equations for fluid, glucose and albumin
transport with the relevant boundary and initial conditions. Its aim is to
model ultrafiltration of water combined with inflow of glucose to the tissue
and removal of albumin from the body during dialysis, and it does this by
finding the spatial distributions of glucose and albumin concentrations and
hydrostatic pressure. The model is developed in one spatial dimension
approximation and a governing equation for each of the variables is derived
from physical principles. Under certain assumptions the model are simplified
with the aim of obtaining exact formulae for spatially non-uniform steady-state
solutions.
As the result, the exact formulae for the fluid fluxes from blood to tissue
and across the tissue are constructed together with two linear autonomous ODEs
for glucose and albumin concentrations in the tissue. The obtained analytical
results are checked for their applicability for the description of
fluid-glucose-albumin transport during peritoneal dialysis.Comment: 28 pages, 8 figures. arXiv admin note: text overlap with
arXiv:1110.128
Quantitative Histomorphometry of the Healthy Peritoneum
The peritoneum plays an essential role in preventing abdominal frictions and adhesions and can be utilized as a dialysis membrane. Its physiological ultrastructure, however, has not yet been studied systematically. 106 standardized peritoneal and 69 omental specimens were obtained from 107 patients (0.1-60 years) undergoing surgery for disease not affecting the peritoneum for automated quantitative histomorphometry and immunohistochemistry. The mesothelial cell layer morphology and protein expression pattern is similar across all age groups. Infants below one year have a thinner submesothelium; inflammation, profibrotic activity and mesothelial cell translocation is largely absent in all age groups. Peritoneal blood capillaries, lymphatics and nerve fibers locate in three distinct submesothelial layers. Blood vessel density and endothelial surface area follow a U-shaped curve with highest values in infants below one year and lowest values in children aged 7-12 years. Lymphatic vessel density is much lower, and again highest in infants. Omental blood capillary density correlates with parietal peritoneal findings, whereas only few lymphatic vessels are present. The healthy peritoneum exhibits major thus far unknown particularities, pertaining to functionally relevant structures, and subject to substantial changes with age. The reference ranges established here provide a framework for future histomorphometric analyses and peritoneal transport modeling approaches. © 2016, EDP Science. All rights reserved