Measurement of total phospholipids in urine of patients treated with gentamicin.
OBJECTIVE
The excretion of phospholipids in urine may be a marker of the early renal toxicity of the aminoglycoside antibiotics. Urinary phospholipids are formed in myeloid bodies which develop in the lysosomes of proximal tubules during treatment with the aminoglycosides, and overflow into the urine.


METHODS
Published assays were modified in order to measure the total phospholipid concentrations in human urine. Phospholipids were extracted from freeze-dried urine samples, digested in concentrated sulphuric acid, and the inorganic phosphorus content determined by complexing with ammonium molybdate and measuring the absorbance at 820 nm. Ten septicaemic patients treated with gentamicin for 5-7 days had significantly higher urine phospholipid concentrations than 10 healthy untreated control subjects (P < 0.0001). There was a negative linear relationship between phospholipid excretion and creatinine clearance (r2 = 0.71).


RESULTS
In 34 patients with acute pyelonephritis, increased phospholipid concentrations were observed prior to treatment compared with healthy controls (P < 0.001) and did not alter during treatment with gentamicin. However, the phospholipid concentrations decreased significantly after treatment was completed (P < 0.03).


CONCLUSIONS
These studies suggest that urinary phospholipids may indicate early aminoglycoside toxicity but with poor specificity, as many of the infections being treated may themselves be associated with phospholipiduria.
Saunders
D A
DA
Christchurch School of Medicine, New Zealand.
Begg
E J
EJ
Kirkpatrick
C M
CM
Yeo
J
J
Graham
G G
GG
Bailey
R R
RR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D004396:Coloring Agents / Q000737:chemistry; D003404:Creatinine / Q000652:urine; D062787:Drug Overdose / Q000652:urine; D005260:Female; D005612:Freeze Drying; D005839:Gentamicins / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D008982:Molybdenum / Q000737:chemistry; D010743:Phospholipids / Q000652:urine*; D011704:Pyelonephritis / Q000188:drug therapy / Q000652:urine; D018805:Sepsis / Q000188:drug therapy / Q000652:urine; D013055:Spectrophotometry, Infrared
D000900:Anti-Bacterial Agents; D004396:Coloring Agents; D005839:Gentamicins; D010743:Phospholipids; D008982:Molybdenum; D003404:Creatinine; C022175:ammonium molybdate