779

Letters to the Editor

Letters to the Editor Serum gamma-glutamyl transferase activity in volunteer blood donors

activity co]impared to females, as noted iin many prev bious studies, and this differenc e was obsenved at each age level. There wais no alteratiion of activity with advancinIg age. A log normal distribution curve wi iS observed ffor both sexes. Further studi(Ds are under way to determine the effect (Af short- andd long-term plasmapheresis on enzyme levvels.

Effective thyroxine ratio and venous stasis

Increased venous pressure can produce a Serum gamma-glutamyl transferase (EC protein-free exudate at the capillary level 2.3.2.2; GGT) activity is a sensitive index and thus increase the concentration of of liver function, and raised levels are plasma proteins and the substances bound found in a wide range of liver diseases to them. Both the upright posture and (Rosalki, 1975). While normal values for venous compression can significantly GGT activity have been reported by increase serum concentrations of the many workers, the majority of these are highly protein-bound thyroid hormones, based on limited numbers. There is need thyroxine and triiodo-thyronine (Judd et for further information on the range of Reference al., 1975). The effective thyroxine ratio variation in healthy adults, particularly (ETR), however, being proportional to with regard to variation with age. The Rosalki, ES. B. (1975). Gamma-glutam,yl the free or non-protein bound circulating purpose of this study was to measure the transpepptidase. Advances in Clinic al thyroxine concentration (Wellby et al., range of GGT activity in a healthy nonChemist,try, 17, 53-107. 1973), should not be affected by venous hospitalised population. stasis. The following observations have Nine hundred and twenty-nine ranv. MrIw )VIC, H. PATAPIOU, S. J. MACHI] N, verified this. domly selected healthy blood donors, B. AL. MCVERRY. and T. E. CLEGHOR1N Blood was collected from healthy attending for their regular six-monthly North Lcondon Blood Transfusion Centr e, volunteers without stasis and also 10-15 donation, participated in this study. GGT Edgware, MiddlesE ?x minutes after a sphygmomanometer cuff activity was determined on an LKB 8600 CHANGE IN E.T.R. WITH VENOUS STASIS Reaction Rate Analyser using reagents prepared in our laboratory. Serum (0 1 ml) Change oin E.T.R. was incubated with L-y-glutamyl-pnitroanilide in water (1 0 ml; 4-6 mmol/l) for 15 minutes at 35°C. The activating 0 03 substrate was glycylglycine in tris (hydroxy* 0-02 ft methyl)aminomethane hydrochloride 0*01 buffer (0-1 ml; 575 mmol/l). The reaction Chang in Total Protein O . rate was followed spectrophotometrically 20 25 (9/1) -0*01 * * * at 410 nm. The final conditions in the -0-02 reaction mixture were as follows: L-y-0-03 glutamyl-p-nitroanilide--4 0 mmol/l; glycylglycine-50.0 mmol/l; tris(hydroxymethyl)aminomethane hydrochloride190 mmol/l; pH 8-05. Post donation Figure Median difference between non stasis and serum samples were used in this study and tourniquet specimens = 0. No significant difference by between batch variation was of the order Wilcoxon signed ranks test (Wilcoxon, 1945) (p > 10%) of 1-5 IU. 95% reference range for ETR = 0 94-1-06. Our results are shown in the Table. Males had consistently higher levels of o

10

Table GGT values Sex

15

30

(IUIl) from 929 blood donors

Age (yr)

Number

Range

Percentile

Logarithmic

tested Male

Total Female

18-29 30-39 40-49 50-65 18-29 30-39 40-49

50-65 Total

Study group

203 155 107 102 573 161 72 55 68 356 929

mean 5-76 7-79 7-63 5-64 5-79 3-38 7-42 4-42 5-86 3-86 3-86

5th

25th

50th

75th

95th

13 14 14 14 13 11 11 11 11 11 12

17 18 19 20 18 13 13 14 14 13 15

20 22 24 23 22 16 16 16 17 16 20

26 31 34 32 29 19 21 23 23 21 26

42 56 56 59 51 31 33 37 46 35 47

21.3

23.0 23-0 24.7 23-6 16.1 16-6 16-5 18-0 16-5 19.9

Serum gamma-glutamyl transferase activity in volunteer blood donors.

779 Letters to the Editor Letters to the Editor Serum gamma-glutamyl transferase activity in volunteer blood donors activity co]impared to females,...
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