HETEROGENEITY OF BRAIN OXYGENATION

由于一些未知的原因，LiPc晶体在低温下不是非常稳定。 一定条件 例如，众所周知， 在纯净水和大脑中几个月后对氧气敏感 但是肌肉在几天内会失去对氧气的敏感性。 博士 Sutcliffe观察到LiPc在使用时明显不稳定， 不清楚这是否仅仅是由于LiPc的质量 他 在英国食品研究所的研究中，这是 发现酞菁锂的氧敏性能 当放置在不同类型的 油. 因此，对酞菁锂晶体的稳定性进行了系统的研究 在向日葵油中进行了使用充分表征的LiPc。 五 将来自两个不同批次的晶体置于特氟隆管中 装满了向日葵籽油 三种晶体（来自一批）具有 第一天和第二天对氧气的敏感性相同， 月后 两个LiPc晶体（来自不同批次）仅具有 第一天一半的灵敏度和完全没有灵敏度 两个月后。 这项实验表明，我们还没有完全 了解影响稳定性的因素 LiPc晶体的氧敏感特性。 虽然这是 问题，它也提出了希望，有了这样的理解，我们可以 能够进一步提高它们在组织如肌肉中的稳定性 目前它们不能使用超过几天。

For some unknown reasons LiPc crystals are not very stable under certain conditions. For example it is well known that these crystals are sensitive to oxygen after a few months in pure water and in brain but in a muscle lose their sensitivity to oxygen in a few days. Dr. Sutcliffe observed apparent instability of LiPc when in use but it was not clear if this was due only to the quality of the LiPc available to him. In studies at the Institute of Food Research in the U.K., it was found that the oxygen sensitive properties of lithium phthalocyanine appeared to vary more than expected when placed in different types of oils. Therefore a systematic study of the stability of LiPc crystals in sunflower oil was undertaken using well characterized LiPc. Five crystals from two different batches were placed in a Teflon tube filled with sunflower oil. Three crystals (from one batch) had the same and the usual sensitivity to oxygen on the first day and two months later. Two LiPc crystals (from a different batch) had only half of the sensitivity on the first day and no sensitivity at all after two months. This experiment indicates that we do not yet fully understand the factors which affect the stability of the oxygen-sensitive properties of LiPc crystals. While this is problematic, it also raises hope that with such understanding, we may be able to improve further their stability in tissues such as muscles where currently they cannot be used for more than a few days.