X-Message-Number: 9766
From: Eugene Leitl <>
Date: Sun, 24 May 1998 16:11:50 +0400 (MSD)
Subject: FYI:CARDIAC ARREST AND RECOVERY OF NEURONAL ACTIVITY 

From http://scienceweek.com , Science-Week 22 May 98

12. CARDIAC ARREST AND RECOVERY OF NEURONAL ACTIVITY
Cardiac arrest lasting a few seconds to a few minutes can be
reversed (by cardiopulmonary resuscitation) without brain damage.
However, after cardiac arrest that lasts longer, reperfusion of
the brain is accompanied by delayed irreversible brain damage
that occurs several days after the reperfusion of brain tissue.
The post-ischemic period during which neuronal activity recovers,
but which precedes the appearance of delayed irreversible damage,
constitutes a therapeutic window in which to prevent delayed cell
death. In animal models of global ischemia at normal temperatures
it has been shown that this post-ischemic period occurs even
after a complete interruption of cerebral blood flow lasting up
to 1 hour. ... ... Charpak and Audinat (Centre National de la
Recherche Scientifique, FR) report a study to evaluate the
maximal duration of cardiac arrest compatible with the occurrence
of the postischemic recovery period, the study involving analysis
of the early phase of the period in acute preparations of brain
tissue (rat and guinea pig) prepared after a cardiac arrest of
several hours and maintained in vitro. The authors report that
during a permanent cardiac arrest, rodent brain tissue is
physiologically preserved in situ in a particular quiescent state
characterized by the absence of electrical activity and by a
critical period of 5 to 6 hours during which brain tissue can be
reactivated (both neurophysiologically and biochemically) upon
restoration of a simple energy supply (glucose/oxygen). The
authors suggest that in rodents the duration of cardiac arrest
compatible with a short-term recovery of neuronal activity is
much longer than previously expected, and that analysis of the
parameters that regulate this duration may bring new insights
into the prevention of post-ischemic damage.
QY: S. Charpak ()
(Proc. Natl. Acad. Sci. US 14 Apr 98 95:4748)
(Science-Week 22 May 98)

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