Owunwanne A, Omu A, Patel M, Mathew M, Ayesha A, Gopinath S
Department of Nuclear Medicine, Faculty of Medicine, Kuwait University.
J Nucl Med. 1998 Oct;39(10):1810-3.
Placental binding and transfer of 99mTc d, 1-hexamethyl propyleneamine oxime (HMPAO) was studied in vitro using human placenta and pregnant guinea pigs.
Five pieces of human placenta were incubated in 50 ml Earle's solution containing 1.85 MBq 99mTc d, 1-HMPAO. The percent binding of the tracer to the placenta per 1 ml standard solution was calculated. Pregnant guinea pigs representing first, second and third trimesters were each injected with 74 MBq 99mTc d, 1-HMPAO through the jugular or femoral vein after sedation was induced with pentabarbital sodium. Static images were obtained, the guinea pigs were killed, and the fetuses were removed, weighed and imaged separately. The placentas, maternal and fetal brains, lungs, livers and kidneys also were removed, and the radioactivity was assayed in a dose calibrator for each organ. The percent radioactivity in each organ was calculated.
The binding of 99mTc d, 1-HMPAO to human placenta ranged from 2.95% +/- 1.5% to 5.82% +/- 0.3% per 1 ml standard solution. Both the binding of 99mTc d, 1-HMPAO to guinea pig placenta and its transfer to the fetus increased with gestational age. The percent binding ranged from 0.09% +/- 0.06% to 0.43% +/- 0.05%, whereas that of transfer to the fetus ranged from 0.05% +/- 0.03% to 2.19% +/- 0.64%. Of the amount transfered to the fetus, the order of accumulation in the fetal organs was liver > blood >> brain > lungs > kidneys > heart.
Technetium-99m d, 1-HMPAO binds to the placenta, and a minimal amount crosses the placental barrier and is transfered into the fetal circulation, mostly in the liver but a measurable amount is found in brain tissue.
使用人胎盘和怀孕豚鼠在体外研究了99mTc d，1-六甲基丙烯胺肟（HMPAO）的胎盘结合和转运。
将五块人胎盘在含有1.85 MBq 99mTc d，1-HMPAO的50 ml Earle's溶液中孵育。计算每1 ml标准溶液中示踪剂与胎盘的结合百分比。用戊巴比妥钠诱导镇静后，分别经颈静脉或股静脉给代表妊娠第一、第二和第三孕期的怀孕豚鼠注射74 MBq 99mTc d，1-HMPAO。获取静态图像，处死豚鼠，取出胎儿，称重并分别成像。还取出胎盘、母鼠和胎儿的脑、肺、肝和肾，并在剂量校准仪中对每个器官进行放射性测定。计算每个器官中的放射性百分比。
每1 ml标准溶液中99mTc d，1-HMPAO与人胎盘的结合率为2.95%±1.5%至5.82%±0.3%。99mTc d，1-HMPAO与豚鼠胎盘的结合及其向胎儿的转运均随胎龄增加而增加。结合百分比为0.09%±0.06%至0.43%±0.05%，而向胎儿的转运百分比为0.05%±0.03%至2.19%±0.64%。在转运至胎儿的量中，胎儿器官中的蓄积顺序为肝脏＞血液＞＞脑＞肺＞肾＞心脏。
锝-99m d，1-HMPAO与胎盘结合，少量穿过胎盘屏障并进入胎儿循环，主要在肝脏中，但在脑组织中也可检测到一定量。
