In vivo measurement of force in the ureter. 2. Influence of urinary flow.

By means of a newly developed measuring catheter the occluding force of the ureter under changing diuresis conditions was investigated using 12 canine ureters. Even under extremely high flow rates of some 50 times normal values, the ureter returned after short phases of noncoaptive transport to active bolus transport. No direct connection between flow rate and basal pressure on the one hand and the form of transport on the other hand was observable. Only after prolonged continuous loading on the ureter with high flow rates was a loss of occluding forces observed with the noncoaptive form of transport, then taking on more significance.

[Stimulation of hematopoietic stem cells with serum specimens of patients with polycythemia vera]. / Stimulation hämatopoietischer Vorläuferzellen durch Serumphroben von Patienten mit Polycythaemia vera.

Mononuclear cells from the peripheral blood of normals and patients with terminal renal insufficiency on hemodialysis were set up in methylcellulose cultures with and without addition of sera of patients with polycythemia vera (pv). In renal patients we found more intensive stimulation of hematopoietic progenitor cells after addition of pv-sera than in normals. The findings suggest a hematopoietic factor in sera of pv which is not identical with erythropoietin.

[Long-term cultures in polycythaemia vera as proof for dependence on erythropoietin (author's transl)]. / Langzeitkulturen bei Polycythaemia vera zum Nachweis von Erythropoetinabhängigkeit.

In eight patients suffering from polycythaemia vera, the proliferation of erythroid colonies in methylcellulose with and without exogenous erythropoietin was studied. After three and five weeks, respectively, no colonies grew. Due to addition of erythropoietin more erythroid colonies proliferated which could be cultivated over nine weeks. The experiments suggest that the erythropoiesis in polycythaemia vera depends on erythropoietin.