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25. The effect of dimethyl sulfoxide on oxygen consumption in cold-exposed rats and hamsters
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ANNUAI~ M E E T I N G A B S T R A C T S
tions of electrolytes to increase above normal levels. Contractile function and electron microscopic structure of the test preparation (guinea pig and after the following tre'.ttments: a) DMSO (1.4 .~I) without freezing, b) freezing to --79°C alone, c) freezing to - 7 9 ° C with D M S O (1.4 ,~ initially), and d) freezing to - 7 9 ° C with DMSO (1.4 ,~i initially) but nmintaining the volume, of the liquid phase constant by further additions of DMSO in deionized water as ice forms. The concentration of electrolytes increased to approxinmtely 30 times isotonic in b, to 5 times isotonic in c, and remained constant in d. D M S O (I.4 M) Ca) blocked contractile responses reversibly but did not cause structural damage. Freezing alone (b) totally destroyed contractility, disrupted cellular membranes, and fractured and disorganized the myofilaments. Conventional "slow" freezing to - 7 9 ° C with DMSO (c) caused the uteri to contract spontaneously after thawing. The electron microscopy again indicated severe damage to the cellular membranes, but the contractile myofilaments were better preserved with fewer fractures. Freezin~ to --79°C with DMSO by the method that attempts to maintain control concentration of electrolytes (d) allowed the recovery of normal contractile function. The cellular membranes were intact, and the myofilaments were not fractured or disorganized. These results show a correlation between the extent of cellular damage and the rise in the concentrations ot electrolytes during freezing by the different methods. 25. T h e Effect o f D i m e t h y l Sulfoxide o n O x y g e n C o n s u m p t i o n in Cold-Exposed Rats and Hamsters2 T. M. ~VALKER,*J. L. ALr~m]o,* A~D J. A. PAI~USKA (Department of Biology, G(,orgetown Umversity, Washington, D.C.). The O_~ consumption of 24 unrestrained and unshaved adult male rats and 24 golden hamsters at an ambient temperature of 4 to 7°C was measured for 3 hr~ in an open circuit metabolism system. Rats received 3 or 6 g per kg of D M S O in about 5 ml of saline ip; hamsters received 3 or 6 g per kg of D M S O in 2 ml of saline. Controls received equivalent amounts of saline alone. Saline con.trols remained normothermic, but, dependent on size of dose, the body temperature of D M S 0 treated animals gradually fell 3 to 5°C. Rats treated with 3 g per kg of D M S O showed 14% less O., conmlmption than saline controls after 30 rain; 21% less after 60 rain; 18%, 90 min; 21% 120 rain; Supported in part by U.S. Army Contract :DA, 49-193-MD-2668.
17%, 150 rain; and 18%, 180 rain. Hamsters treated with 3 g per kg of DMSO used 23% le.ss oxygen ihan saline controls after 30 min; 31% after 60 rain; 25% after 90 rain; 33% after 120 rain; 33% after 150 min; and 37% after 180 rain. The 6 g per kg close caused greater depression of O... consumption (rats, 27%; hamsters, 34%) only during the first 30 rain. Although DMSO-treated subjerts at times were. less active than controls, it does not apl)ear that activity alone can adequately explain the consistent difference in the results. The decline in body teml)erature cannot be the primary cause of lowere(! 0: consumption since the reduction in O, consumption occurred even before the f,,tll in body temperature. It appears, therefore, that the oxygen consumption of these cold-exposed rats and hamsters was affected by the DMSO treatment. 26. Continuous Measurement o f Tissue Uptake o f D i m e t h y l Sulfoxide. B. C. ELFORD* AND J. FA~tR:~,NT (National Institute for Medical Research, Mill Hill, London, England). The method of cooling tissues to - 7 9 ° C without allowing freezing to take place involves increasing the external concentration of D M S O as cooling proceeds. The application of this principle will require a quantitative measure of the tissue uptake of D M S O at different temperatures. One method of following the influx or effiux of D M S O has been developed for isolated tissues. The apparent (immersed) weight of the tissue is continuously recorded using ~m electronic microbalance. As the solution containing the D M S O diffuses into the tissue the apparent weight increases because of the difference in density. The large scale loss of lissue water caused by the transient osmotic effects of the solution containing the D M S O reduces the real weight and the upthrust by almost the same amount. The contribution to the apparent weight change c a u ~ d by these osmotic effects (;an be determined for each influx or effiux, and thus it is possible to follow the movement of the D M S O without interference from water movement. The validity of this method has been assessed by comparing it with effiux curves obtained under identical experimental conditions from tissues preloaded with S~-DMSO. The uptake of D M S O into isolated strips of smooth muscle has been studied using this technique. It was possible to separate the influx or efflux curves into extracellular and intracellular components, and the temperature dependence of these separate diffusional processes is at present under investigation.
ANNUAI~ M E E T I N G A B S T R A C T S
tions of electrolytes to increase above normal levels. Contractile function and electron microscopic structure of the test preparation (guinea pig and after the following tre'.ttments: a) DMSO (1.4 .~I) without freezing, b) freezing to --79°C alone, c) freezing to - 7 9 ° C with D M S O (1.4 ,~ initially), and d) freezing to - 7 9 ° C with DMSO (1.4 ,~i initially) but nmintaining the volume, of the liquid phase constant by further additions of DMSO in deionized water as ice forms. The concentration of electrolytes increased to approxinmtely 30 times isotonic in b, to 5 times isotonic in c, and remained constant in d. D M S O (I.4 M) Ca) blocked contractile responses reversibly but did not cause structural damage. Freezing alone (b) totally destroyed contractility, disrupted cellular membranes, and fractured and disorganized the myofilaments. Conventional "slow" freezing to - 7 9 ° C with DMSO (c) caused the uteri to contract spontaneously after thawing. The electron microscopy again indicated severe damage to the cellular membranes, but the contractile myofilaments were better preserved with fewer fractures. Freezin~ to --79°C with DMSO by the method that attempts to maintain control concentration of electrolytes (d) allowed the recovery of normal contractile function. The cellular membranes were intact, and the myofilaments were not fractured or disorganized. These results show a correlation between the extent of cellular damage and the rise in the concentrations ot electrolytes during freezing by the different methods. 25. T h e Effect o f D i m e t h y l Sulfoxide o n O x y g e n C o n s u m p t i o n in Cold-Exposed Rats and Hamsters2 T. M. ~VALKER,*J. L. ALr~m]o,* A~D J. A. PAI~USKA (Department of Biology, G(,orgetown Umversity, Washington, D.C.). The O_~ consumption of 24 unrestrained and unshaved adult male rats and 24 golden hamsters at an ambient temperature of 4 to 7°C was measured for 3 hr~ in an open circuit metabolism system. Rats received 3 or 6 g per kg of D M S O in about 5 ml of saline ip; hamsters received 3 or 6 g per kg of D M S O in 2 ml of saline. Controls received equivalent amounts of saline alone. Saline con.trols remained normothermic, but, dependent on size of dose, the body temperature of D M S 0 treated animals gradually fell 3 to 5°C. Rats treated with 3 g per kg of D M S O showed 14% less O., conmlmption than saline controls after 30 rain; 21% less after 60 rain; 18%, 90 min; 21% 120 rain; Supported in part by U.S. Army Contract :DA, 49-193-MD-2668.
17%, 150 rain; and 18%, 180 rain. Hamsters treated with 3 g per kg of DMSO used 23% le.ss oxygen ihan saline controls after 30 min; 31% after 60 rain; 25% after 90 rain; 33% after 120 rain; 33% after 150 min; and 37% after 180 rain. The 6 g per kg close caused greater depression of O... consumption (rats, 27%; hamsters, 34%) only during the first 30 rain. Although DMSO-treated subjerts at times were. less active than controls, it does not apl)ear that activity alone can adequately explain the consistent difference in the results. The decline in body teml)erature cannot be the primary cause of lowere(! 0: consumption since the reduction in O, consumption occurred even before the f,,tll in body temperature. It appears, therefore, that the oxygen consumption of these cold-exposed rats and hamsters was affected by the DMSO treatment. 26. Continuous Measurement o f Tissue Uptake o f D i m e t h y l Sulfoxide. B. C. ELFORD* AND J. FA~tR:~,NT (National Institute for Medical Research, Mill Hill, London, England). The method of cooling tissues to - 7 9 ° C without allowing freezing to take place involves increasing the external concentration of D M S O as cooling proceeds. The application of this principle will require a quantitative measure of the tissue uptake of D M S O at different temperatures. One method of following the influx or effiux of D M S O has been developed for isolated tissues. The apparent (immersed) weight of the tissue is continuously recorded using ~m electronic microbalance. As the solution containing the D M S O diffuses into the tissue the apparent weight increases because of the difference in density. The large scale loss of lissue water caused by the transient osmotic effects of the solution containing the D M S O reduces the real weight and the upthrust by almost the same amount. The contribution to the apparent weight change c a u ~ d by these osmotic effects (;an be determined for each influx or effiux, and thus it is possible to follow the movement of the D M S O without interference from water movement. The validity of this method has been assessed by comparing it with effiux curves obtained under identical experimental conditions from tissues preloaded with S~-DMSO. The uptake of D M S O into isolated strips of smooth muscle has been studied using this technique. It was possible to separate the influx or efflux curves into extracellular and intracellular components, and the temperature dependence of these separate diffusional processes is at present under investigation.