Ashford A E, Allaway W G, Gubler F, Lennon A, Sleegers J
J Microsc. 1986 Nov;144(Pt 2):107-26. doi: 10.1111/j.1365-2818.1986.tb02793.x.
An apparatus for embedding tissues at resin temperatures down to 228 K is described. By placing thermocouples in the resin the temperature has been monitored during embedding at low temperature with glycol methacrylate (GMA) and Lowicryl K4M. Even in this apparatus with a liquid cooling bath the heat of polymerization is not dissipated and the resin temperature rises. This rise is directly proportional to the resin temperature at the onset of polymerization and is higher in Lowicryl K4M than GMA. The initial resin temperature also affects the time taken for polymerization. The time to the onset of the peak and its duration are both increased as the temperature is lowered. This effect is more pronounced with GMA than Lowicryl K4M and polymerization of GMA is inhibited at the lowest temperature used. When Lowicryl K4M, polymerized at low temperature, is warmed up to ambient a further exothermic reaction occurs, which causes the resin temperature to rise well above ambient. Both this temperature peak and that during polymerization are reduced, but not totally eliminated, by reducing the resin volume. Air-cooled systems are inefficient compared with the low-temperature apparatus used here and the resin temperature rise is consequently greater and, even with small resin volumes, it can be very high. It is therefore unlikely for published methods that the temperature specified has been maintained in the resin during polymerization. The implications of these findings are discussed in relation to enzyme and antigen survival. Recommendations include use of very small volumes of resin, refrigerated liquid-bath rather than air-cooled systems and contact with a heat sink when specimens are warmed up to ambient temperature. Examples of enzyme reaction, antigen survival and structural preservation obtained with the method are presented.
本文描述了一种用于在低至228K的树脂温度下包埋组织的装置。通过在树脂中放置热电偶，在使用甲基丙烯酸乙二醇酯（GMA）和低温包埋剂K4M进行低温包埋过程中对温度进行了监测。即使在带有液体冷却浴的这种装置中，聚合热也不会消散，树脂温度会升高。这种升高与聚合开始时的树脂温度成正比，并且在低温包埋剂K4M中比在GMA中更高。初始树脂温度也会影响聚合所需的时间。随着温度降低，达到峰值的时间及其持续时间都会增加。这种影响在GMA中比在低温包埋剂K4M中更明显，并且在使用的最低温度下GMA的聚合受到抑制。当在低温下聚合的低温包埋剂K4M升温至室温时，会发生进一步的放热反应，这会导致树脂温度升高至远高于室温。通过减少树脂体积，这个温度峰值以及聚合过程中的温度峰值都会降低，但不会完全消除。与这里使用的低温装置相比，风冷系统效率较低，因此树脂温度升高更大，即使树脂体积很小，温度也可能非常高。因此，对于已发表的方法来说，在聚合过程中树脂不太可能保持规定的温度。本文结合酶和抗原的存活情况讨论了这些发现的意义。建议包括使用非常少量的树脂、冷藏液体浴而不是风冷系统，以及在标本升温至室温时与散热器接触。文中还给出了用该方法获得的酶反应、抗原存活和结构保存的实例。
