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Ëeeent research in freezmg, drymg,
and kinetics
_
of thermal degradation of viruses
*
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DONALD GREIFF Sc. D.
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mousson or PA'I‘HOLOGY, MAi{QUŒE UNIVERSITY SCHOOL OF MEDICINE, M1LWAUŒ, WISCONSIN (U.S.A.)
'WILTON RIGHTSEL Ph. D.
,
RESEARCH LABORAT‘ORŒS PARKB, DAVIS & COMPANY, Dmom MICHIGAN (U.S.A.)
The technique of drying by ‘sublimation in vdcuo (lyophization) -is used today for the
preservation of morphological structures, biochemical characteristics and physiological
activities of a multitude of biological materials. Investigators concerned with the preserva—
tion of the infective characteristics of bacteria and viruses Were among the rst to use
freezing and drying from the frozen state by vacuum sublimation of water. The various
methods used and apparatus employed forthe above resulted in dried bacteria and viruses
which were viable after rehydraition; only recently have efforts been directed toward
obtaining maximum survival in the case of bacteria Or inaXimum retention of infectivity
in the case of viruses.
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f
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]
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The problems associated With the freezing and._3drying
z_‘11 —“yàcÿ‘o
of Suspensions of viruses can be divided into three.bas1c
1;)Thc preparatiOn-ofthe
material, including the addition of protectiVe substances; 2)
and rates
of freezing, and the temperatures of storage, or the temperatures
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of water
and 3) the thawing of
suSpehsiOns, or
the rehydration‘ôfA—theÿ ‘driéd‘
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product, and the measurement of the
reconstitutcd‘ bi010gîc
preparations.
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Ï _
…
Dependent on the virus being Studied, _eitherf_cells‘ofcmbryonate
tissue cultures were used as
ÎfOf rephcatlonof
suitable periôd
.
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"‘-Those portions of these
SUPPOŸŒd:
,
in,‘part, by Grant No. Al-O4137
Serviçe and by
,
_
-
:
:_COntraètNo“.‘AT(ll-l)596 of theÎU.
_‘
ï
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