Definition: Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
Input: Abstract: We studied the effects of one session of hemofiltration on the mineral metabolism in a group of uremic children. We observed an increase of calcemia, accompanied by positive calcium balance, and a decrease of plasma phosphate and PTH-MM. No substantial loss of plasma 25-OH D was found. It is concluded that hemofiltration has a positive effect on calcemia and is very effective in removing phosphate, but it acts only temporarily on PTH removal. An adequate calcium concentration must be provided in the substitution fluid.

Mineral metabolism during a hemofiltration session in children.