脳損傷と体液の酵素変動

BRAIN DAMAGE AND ENZYMATIC ACTIVITIES IN BODY FLUID

I．緒言

　近年頭部外傷が急激に増加し，死因統計の上でも1961年には第7位となり^10），脳神経外科領域で扱う疾患のなかで重要な地位をしめるようになつてきた。しかし頭部外傷患者に対して適切な処置をとるために，脳損傷の程度を知り，かつ予後を判定するための化学的検査法は確立されていない。この研究は頭部外傷の病態生化学的研究の一環として脳損傷の程度と体液中の酵素変動を問題にしたのであるが，それに関連して今日一般化されつつある頭部外傷に対する低体温療法の妥当性についても酵素変動の立場から検討を加えた。

　1954年にLa DueおよびWröblewskiが心筋梗塞を起こした患者の血清中Glutamic oxa—lacetic transaminase （GOT）活性値が異常に上昇し狭心症との鑑別に重要な指針となることを報告して以来，体液の酵素活性値の変動が疾患の化学的検査法として重要視され，各種疾患と体液の酵素変動に関する研究が相ついで報告されるにいたつた。脳神経系疾患においても脳血管障害や脳腫瘍と髄液または血清中のGOT活性値の上昇を論じたGreen^{5）6）7）8）}，　Wakim^40），　Lieber—man^17），　Myerson^21）等の報告，Lactic dehy—drogenase （LDH）に関するGreen^6），　Fleisherら^4）の報告，Phosphohexose isomeraseに関するThompsonら^34）の報告，Cholinesteraseに関するBernsohnら^2）の報告など枚挙にいとまがないほどである。

1) Experimentally produced brain damage by freezing method resulted in the elevationof GOT and GPT levels in the cerebrospinal fluid and serum. Enzymatic activities reached the muximal level within 6 to 24 hours after the damage and returned to normal level within about 7 days. There is a significant correla-tion between the volume of damaged tissue, mortality and the increased enzyme level in the body fluid. GOT level shows more distinct elevation than that of GPT.

2) Elevation of GOT and GPT levels in the cerebrospinal fluid and serum were found in patients with clinical signs of cerebral contu-sion or laceration. The concentration of GOT in the cerebrospinal fluid and the serum can be used as an indicator of the severity of the head injury.

3) Under early hypothermia after brain da-mage, GOT levels in the cerebrospinal fluiddid not show such marked elevation. On the other hand, under delayed hypothermia, no sig-nificant changes in enzymatic levels in the body fluid were oberved as compared with those in case of normothermic brain damage.

4) A phosphoprotein phosphatase acting phosvitin was found in the cerebrospinal fluid. The optimal pH of the enzyme was 5.5. It was activated by Mg²⁺ or Mn²⁺ ions and inhi-bited by Fe²⁺ or CN^- ions. The enzyme in the cerebrospinal fluid appeard to the same phosphoprotein phosphatase derived from the brain. The enzyme liberated phosphate from phosvitin more rapidly than from p-nitrophe-nyl phospate. The phosphoprotein phosphatase level in the cerebrospinal fluid showed marked elevation after experimental brain damage, and in cerebral infarction and meningitis.