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Changes in urine macromolecular composition during processing.
S Maslamani1, P A Glenton, S R Khan
1Department of Pathology, College of Medicine, University of Florida, Gainesville, Florida 32610, USA.
The Journal of Urology
|June 7, 2000
Summary
Urine processing by filtration or centrifugation alters macromolecular composition, affecting crystal formation. This impacts the incorporation of proteins like Tamm-Horsfall protein and prothrombin into calcium oxalate crystals.
Area of Science:
- Biochemistry
- Urology
- Materials Science
Background:
- Urine analysis often involves centrifugation and filtration.
- These processes can remove macromolecules crucial for understanding crystallization.
- Investigating these changes is vital for accurate interpretation of urine composition.
Purpose of the Study:
- To determine how centrifugation and filtration affect urinary macromolecular composition.
- To investigate the impact of these processing methods on protein and lipid content.
- To examine changes in the incorporation of urinary proteins into crystal matrices.
Main Methods:
- Collected 24-hour urine samples from human volunteers.
- Processed samples via filtration, centrifugation, or both; a control remained unprocessed.
- Analyzed total protein and lipid content, performed SDS-PAGE and Western blotting for specific proteins (OPN, PT, IalphaI, THP, ALB).
- Examined protein incorporation into calcium oxalate crystals formed in processed and unprocessed urine.
Main Results:
- Processing significantly reduced protein and lipid content in urine.
- High molecular weight proteins, such as Tamm-Horsfall protein (THP), were notably affected by processing.
- Crystals formed in processed urine showed reduced THP incorporation and increased prothrombin (PT)-related protein incorporation.
- Phospholipids were identified in crystal matrices and processing byproducts.
Conclusions:
- Removal of macromolecules like phospholipids and proteins by processing increases available binding sites on crystal surfaces.
- This selective removal influences the composition of incorporated macromolecules in crystals.
- Processing may alter the milieu, facilitating better access of remaining macromolecules to crystal surfaces.