Huang C C
Department of Pediatrics, National Cheng Kung University Hospital, Tainan, Taiwan, R.O.C.
Zhonghua Min Guo Xiao Er Ke Yi Xue Hui Za Zhi. 1998 May-Jun;39(3):157-65.
Perinatal asphyxia is an important cause of neonatal mortality and subsequent sequelae. Striatum, richly innervated by nigrostriatal dopaminergic projections, is susceptible to perinatal insults. Measuring the cerebral cortical oxygen pressure and striatal extracellular dopamine in the striatum in piglets under different kinds and degrees of hypoxia/ischemia insult, the changes of extracellular striatal dopamine were found to be more related to the changes in blood pressure than with cortical oxygen pressure. After asphyxia, cortical oxygen pressure was significantly higher in piglets breathing 100% O2 than in those breathing 21% O2. Two hours after reoxygenation, there was a secondary release of more dopamine in piglets ventilated with 100% O2 than in those with 21% O2. Although 100% FiO2 after asphyxia increases more cortical oxygenation, it also results in poorer recovery in dopamine metabolism and higher secondary release of striatal dopamine, which may exacerbate post-hypoxic cerebral injury. Striatal lesions may strongly be related with levels of extracellular dopamine during different degrees and kinds of insults. The study of the urine 1H-NMR spectra in newborns within six hours after birth demonstrated that the lactate/creatinine ratio in newborns with subsequent hypoxic-ischemic encephalopathy was significantly higher than in those with perinatal distress only and in normal newborns. The urine lactate/creatinine ratio in newborns with perinatal distress only was also significantly higher than that in normal newborns. The levels of urinary lactate/creatinine by 1H-NMR spectroscopy within six hours after birth correlates well with subsequent hypoxic-ischemic encephalopathy. The characteristics of urine 1H-NMR spectra can be sensitively and specifically used to identify early after birth for the asphyxiated newborns with potential subsequent hypoxic-ischemic encephalopathy.
围产期窒息是新生儿死亡及后续后遗症的重要原因。黑质纹状体多巴胺能投射丰富支配的纹状体易受围产期损伤影响。通过测量不同类型和程度的缺氧/缺血损伤仔猪纹状体内的大脑皮质氧分压和纹状体细胞外多巴胺，发现纹状体细胞外多巴胺的变化与血压变化的关系比与皮质氧分压的关系更为密切。窒息后，呼吸100%氧气的仔猪的皮质氧分压显著高于呼吸21%氧气的仔猪。复氧两小时后，用100%氧气通气的仔猪比用21%氧气通气的仔猪释放出更多的多巴胺。尽管窒息后100%的吸入氧浓度增加了更多的皮质氧合，但它也导致多巴胺代谢恢复较差以及纹状体多巴胺的二次释放增加，这可能会加重缺氧后脑损伤。纹状体损伤可能与不同程度和类型损伤期间的细胞外多巴胺水平密切相关。对出生后6小时内新生儿尿液的1H-NMR光谱研究表明，随后发生缺氧缺血性脑病的新生儿的乳酸/肌酐比值显著高于仅患有围产期窘迫的新生儿和正常新生儿。仅患有围产期窘迫的新生儿的尿液乳酸/肌酐比值也显著高于正常新生儿。出生后6小时内通过1H-NMR光谱法测定的尿液乳酸/肌酐水平与随后的缺氧缺血性脑病密切相关。尿液1H-NMR光谱特征可灵敏且特异地用于出生后早期识别有潜在后续缺氧缺血性脑病的窒息新生儿。
