1017
yet know whether measurement of PAF has any value in the differential diagnosis of cholestasis or whether the changes in activity have any role in the lipoprotein abnormalities sometimes seen in cholestatic disease. We do
not
acetylhydrolase
We thank Mrs Matthaus-Kitzinger, Mrs Albertismeier, and, from Bioscientias Institut fiir Laboruntersuchungen, Ms Hilgert, and Mrs Schmähling for technical assistance. Boehringer Ingelheim KG, D-6507 Ingelheim/Rhein, Germany
CHRISTOPHER J. MEADE
Addenbrooke’s Hospital, Cambridge, UK
SUSAN METCALFE ROSAMUND SVVENNSEN NEVILLE JAMIESON CHRISTOPHER WATSON ROY Y. CALNE
Department of Medicine II, Klinikum Grosshadern, University of Munich, Germany
GERHARD KLEBER
St Philip’s Hospital, London WC2, UK
GUY NEILD
Department of Surgery,
1. Steinbrecher UP, Pritchard PH. Hydrolysis of phosphatidylcholine during LDL oxidation is mediated by platelet-activating factor acetylhydrolase. J Lipid Res 1989; 30: 305-15. 2. Satoh K, Imaizumi T, Kawamura Y, Yoshida H, Takamatsu S, Takamatsu M. Increased activity of the platelet-activating factor acetylhydrolase in plasma low density lipoprotein from patients with essential hypertension. Prostaglandins 1989; 37: 673-82. 3. Satoh K, Imaizumi T, Kawamura Y, et al. Activity of platelet-activating factor (PAF) acetylhydrolase in plasma from patients with ischemic cerebrovascular disease. Prostaglandins 1988; 35: 685-98. 4. Miwa M, Miyake T, Yamanaka T, et al. Characterisation of serum platelet-activating factor (PAF) acetylhydrolase: correlation between deficiency of serum PAF acetylhydrolase and respiratory symptoms in asthmatic children. J. Clin Invest
1988; 82: 1983-91. Jordan L, Russo-Marie F, Bon C. A sensitive and continuous fluorimetric assay for phospholipase A2 using pyrene-labelled phospholipids in the presence of serum albumin. Analyt Biochem 1989; 177: 103-09. 6. Stafforini DM, Carter ME, Zimmerman GA, McIntyre TM, Prescott SM. Lipoproteins alter the catalytic behaviour of the platelet-activating factor acetylhydrolase in human plasma. Proc Natl Acad Sci USA 1989; 86: 2393-97. 7. Satoh K, Imaizumi T, Kawamura Y, et al. Platelet activating factor (PAF) stimulates the production of PAF acetylhydrolase by the human hepatoma cell line HepG2. J Clin invest 1991; 87: 476-81. 8. Smiley PL, Stremler KE, Prescott SM, Zimmerman GA, McIntyre TM. Oxidatively 5. Radvanyi F,
fragmented phosphatidylcholines activate human neutrophils through the receptor for platelet-activating factor. J Biol Chem (in press). 9. Caramelo C, Fernandez-Gallardo S, Santos JC, et al. Increased levels of plateletactivating factor in blood from patients with cirrhosis of the liver. Eur J Clin Invest 1987; 17: 7-11. TJC, De Rijke YB, Kruijt JK. Different fate in vivo of oxidatively modified low density lipoprotein and acetylated low density lipoprotein in rats. Recognition by various scavenger receptors on Kupffer and endothelial liver cells. J Riol Chem 1991; 266: 2282-89.
10. Van Berkel
Serum creatinine rate for
glomerular filtration monitoring cyclosporin therapy or
SIR,-Dr Menter and Dr Barker (July 27,
p 231) suggest that creatinine is a poor indicator of renal dysfunction, glomular filtration rate (GFR) should be monitored when psoriasis patients are treated with cyclosporin (CsA). This proposal should be considered with caution. Firstly, in patients with essentially normal renal function, in contrast to those with chronic renal failure,l the increase in serum creatinine during CsA therapy is closely related to the decrease in GFR.2 In 42 patients treated with CsA for various non-renal autoimmune diseases, GFR measured by inulin or diethylene triaminepenta-acetic acid clearance and serum creatinine were compared. Both were determined before and during CsA therapy (mean dose 3-9 [SEM 17] mg/kg daily, duration 7 [1] months). There was a good correlation (r=0505, p
yet know whether measurement of PAF has any value in the differential diagnosis of cholestasis or whether the changes in activity have any role in the lipoprotein abnormalities sometimes seen in cholestatic disease. We do
not
acetylhydrolase
We thank Mrs Matthaus-Kitzinger, Mrs Albertismeier, and, from Bioscientias Institut fiir Laboruntersuchungen, Ms Hilgert, and Mrs Schmähling for technical assistance. Boehringer Ingelheim KG, D-6507 Ingelheim/Rhein, Germany
CHRISTOPHER J. MEADE
Addenbrooke’s Hospital, Cambridge, UK
SUSAN METCALFE ROSAMUND SVVENNSEN NEVILLE JAMIESON CHRISTOPHER WATSON ROY Y. CALNE
Department of Medicine II, Klinikum Grosshadern, University of Munich, Germany
GERHARD KLEBER
St Philip’s Hospital, London WC2, UK
GUY NEILD
Department of Surgery,
1. Steinbrecher UP, Pritchard PH. Hydrolysis of phosphatidylcholine during LDL oxidation is mediated by platelet-activating factor acetylhydrolase. J Lipid Res 1989; 30: 305-15. 2. Satoh K, Imaizumi T, Kawamura Y, Yoshida H, Takamatsu S, Takamatsu M. Increased activity of the platelet-activating factor acetylhydrolase in plasma low density lipoprotein from patients with essential hypertension. Prostaglandins 1989; 37: 673-82. 3. Satoh K, Imaizumi T, Kawamura Y, et al. Activity of platelet-activating factor (PAF) acetylhydrolase in plasma from patients with ischemic cerebrovascular disease. Prostaglandins 1988; 35: 685-98. 4. Miwa M, Miyake T, Yamanaka T, et al. Characterisation of serum platelet-activating factor (PAF) acetylhydrolase: correlation between deficiency of serum PAF acetylhydrolase and respiratory symptoms in asthmatic children. J. Clin Invest
1988; 82: 1983-91. Jordan L, Russo-Marie F, Bon C. A sensitive and continuous fluorimetric assay for phospholipase A2 using pyrene-labelled phospholipids in the presence of serum albumin. Analyt Biochem 1989; 177: 103-09. 6. Stafforini DM, Carter ME, Zimmerman GA, McIntyre TM, Prescott SM. Lipoproteins alter the catalytic behaviour of the platelet-activating factor acetylhydrolase in human plasma. Proc Natl Acad Sci USA 1989; 86: 2393-97. 7. Satoh K, Imaizumi T, Kawamura Y, et al. Platelet activating factor (PAF) stimulates the production of PAF acetylhydrolase by the human hepatoma cell line HepG2. J Clin invest 1991; 87: 476-81. 8. Smiley PL, Stremler KE, Prescott SM, Zimmerman GA, McIntyre TM. Oxidatively 5. Radvanyi F,
fragmented phosphatidylcholines activate human neutrophils through the receptor for platelet-activating factor. J Biol Chem (in press). 9. Caramelo C, Fernandez-Gallardo S, Santos JC, et al. Increased levels of plateletactivating factor in blood from patients with cirrhosis of the liver. Eur J Clin Invest 1987; 17: 7-11. TJC, De Rijke YB, Kruijt JK. Different fate in vivo of oxidatively modified low density lipoprotein and acetylated low density lipoprotein in rats. Recognition by various scavenger receptors on Kupffer and endothelial liver cells. J Riol Chem 1991; 266: 2282-89.
10. Van Berkel
Serum creatinine rate for
glomerular filtration monitoring cyclosporin therapy or
SIR,-Dr Menter and Dr Barker (July 27,
p 231) suggest that creatinine is a poor indicator of renal dysfunction, glomular filtration rate (GFR) should be monitored when psoriasis patients are treated with cyclosporin (CsA). This proposal should be considered with caution. Firstly, in patients with essentially normal renal function, in contrast to those with chronic renal failure,l the increase in serum creatinine during CsA therapy is closely related to the decrease in GFR.2 In 42 patients treated with CsA for various non-renal autoimmune diseases, GFR measured by inulin or diethylene triaminepenta-acetic acid clearance and serum creatinine were compared. Both were determined before and during CsA therapy (mean dose 3-9 [SEM 17] mg/kg daily, duration 7 [1] months). There was a good correlation (r=0505, p
