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Procoagulant activity in normal human urine associated with subcellular particles
Kidney International
|February 1, 1986
Summary
Procoagulant activity in urine is linked to small particles, not Tamm-Horsfall protein. These particles, measuring 0.1 to 1.1 microns, are likely lipid membranes and carry the urine
Area of Science:
- Urology
- Biochemistry
- Cell Biology
Background:
- Normal human urine exhibits procoagulant activity (PCA).
- The specific structures responsible for PCA in urine were previously unidentified.
Purpose of the Study:
- To identify the structures associated with procoagulant activity in normal human urine.
- To differentiate between fibrous material and particulate matter contributing to PCA.
Main Methods:
- Ultracentrifugation at 100,000g.
- Transmission and scanning electron microscopy.
- Filtration studies using a 0.2-micron filter.
- Differential centrifugation at varying pH.
- SDS-PAGE and Western blotting for protein identification.
Main Results:
- Procoagulant activity was sedimented by ultracentrifugation, indicating a particulate nature.
- Filtration removed over 90% of PCA, confirming association with particles.
- Electron microscopy revealed membrane-bound vesicles and fibrous material (Tamm-Horsfall protein).
- PCA remained with particles (0.1-1.1 micron) after pH-dependent separation; purified Tamm-Horsfall protein showed no PCA.
Conclusions:
- Procoagulant activity in normal human urine is associated with particles 0.1 to 1.1 microns in diameter.
- These particles are likely lipid membranes in various arrangements.
- Tamm-Horsfall protein, though present, does not contribute to the observed procoagulant activity.