X-Message-Number: 11929
Date: Wed, 9 Jun 1999 17:18:19 -0700 (PDT)
From: Doug Skrecky <>
Subject: effect of erythritol on freezing damage

Authors
  Loeb WF.  Das SR.  Trout JR.
Institution
  Ani Lytics Inc., Gaithersburg, Maryland 20877, USA.
Title
  The effect of erythritol
  on the stability of gamma-glutamyl transpeptidase and
  N-acetyl glucosaminidase in human urine.
Source
  Toxicologic Pathology.  25(3):264-7, 1997 May-Jun.
Abstract
  In toxicology studies and clinical trials of erythritol,
  treated animals and human subjects had higher urine gamma-glutamyl
  transpeptidase [gamma-glutamyl transferase (gamma-GT)] than untreated
  controls. It has previously been reported that gamma-GT activity in frozen
  urine decreases with time; therefore, a study was undertaken
  to examine the effects of storage
  temperature, time, and the presence of
  erythritol on the stability of gamma-GT and
  N-acetyl glucosaminidase in human urine. In this study, it was found that
  the rate of decrease of the activity of
  gamma-GT is much greater at -20 degrees C than at -70 degrees C. Variation in
  the storage temperature of the frozen urine
  is particularly deleterious to gamma-GT. The addition of
  erythritol in a concentration of 5% reduces this decrease.
  Approximately 15% of N-acetyl glucosaminidase activity is lost in
  the initial process of freezing the urine.
  Thereafter, conditions of temperature, time, and
  the presence or absence of erythritol
  account for little additional loss of activity.

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