RAPID AND UNIFORM ELECTROMAGNETIC HEATING OF AQUEOUS CRYOPROTECTANT SOLUTIONS FROM CRYOGENIC TEMPERATURES
RAPID AND UNIFORM ELECTROMAGNETIC HEATING OF AQUEOUS CRYOPROTECTANT SOLUTIONS FROM CRYOGENIC TEMPERATURES
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DOI：
10.1016/0011-2240(90)90035-3
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发表时间：
1990-10-01
期刊：
影响因子：
2.7
通讯作者：
FAHY, GM
中科院分区：
文献类型：
--
作者：
RUGGERA, PS;FAHY, GM
去玻璃化(升温过程中结冰)是器官玻璃化(固化而不结冰)成功的主要障碍之一。目前，克服大器官中玻璃化或其破坏性影响的唯一可行方法似乎是使用某种形式的电磁加热(EH)来实现所需的高加热速率。EH在这种应用中的一个复杂情况是需要在钢制压力容器内升温。我们以前曾报道过，谐振式射频(RF)螺旋线圈在环境温度和低加热速率下提供非常均匀的加热，并且可以针对同轴功率传输进行修改，如果只有一根电缆穿透压力容器的壁，则必须进行同轴功率传输。我们现在报告我们使用改进的螺旋线圈、高射频输入功率和低温水溶液[60%(w/v)4.37M二甲基亚砜和4.37M乙酰胺在水中和50%(w/w)1，2-丙二醇]的低温保护剂溶液进行的初步研究。我们还描述了这类研究所需的电子设备。在高功率条件下，使用Luxtron光纤探头监测温度。体温测量因使用探头插入和引导所需的导管而变得复杂。我们使用导尿管观察到的最高升温速率出现在大约-70到-40度的温度范围内。在缓慢升温过程中，不稳定溶液中通常会出现脱玻璃化的温度区域。我们发现，在这个范围内，我们可以获得约300度的测量升温速率。在30到130毫升的样品中，使用200到700 W的射频功率，不会在任何点过热样品。然而，节能计算表明，我们测量的峰值加热率可能比我们大部分解决方案中的真实加热率高得多。我们能够估计出整体的真实加热率，得到的平均值约为20度。C/min/100W/100ml，这意味着加热效率接近100%。似乎有可能在高压条件下足够快地加热玻璃化的兔肾，以保护它们不被玻璃化。
Devitrification (ice formation during warming) is one of the primary obstacles to successful organ vitrification (solidification without ice formation). The only feasible approach to overcoming either devitrification or its damaging effects in a large organ appears at present to be the use of some form of electromagnetic heating (EH) to achieve the required high heating rates. One complication of EH in this application is the need for warming within a steel pressure vessel. We have previously reported that resonant radiofrequency (RF) helical coils provide very uniform heating at ambient temperatures and low heating rates and can be modified for coaxial power transmission, which is necessary if only one cable is to penetrate through the wall of the pressure vessel. We now report our initial studies using a modified helical coil, high RF input power, and cryogenic aqueous cryoprotectant solutions [60% (w/v) solution of 4.37 M dimethylsulfoxide and 4.37 M acetamide in water and 50% (w/w) 1,2-propanediol]. We also describe the electronic equipment required for this type of research. Temperatures were monitored during high-power conditions with Luxtron fiberoptic probes. Thermometry was complicated by the use of catheters needed for probe insertion and guidance. The highest heating rates we observed using catheters occurred at temperatures ranging from about -70 to -40.degree. C, the temperature zone where devitrification usually appears in unstable solutions during slow warming. We find that in this range we can achieve measured heating rates of approximately 300.degree. C/min in 30- to 130-ml samples using 200 to 700 W of RF power without overheating the sample at any point. However, energy conservation calculations imply that our measured peak heating rates may be considerably higher than the true heating rates occurring in the bulk of our solutions. We were able to estimate the overall true heating rates, obtaining an average value of about 20.degree. C/min/100 W/100 ml, which implies a heating efficiency close to 100%. It appears that it should be possible to warm vitrified rabbit kidneys rapidly enough under high-pressure conditions to protect them from devitrification.