冷冻切片机防卷板远距操作装置的设计与应用

目的:为了防止实验人员操作冷冻切片机防卷板过程中手部长时间受凉、冻伤以及过长时间弯腰而引发劳损。方法:在切片机防卷板侧旁设计、安装一个连轴、变轴装置,一端连接套牢防卷板的操作手柄,一端通过推拉操作防卷板手柄,推拉位置高于切片机玻璃门水平。结果:在安装了远距操作装置后,避免了手部寒冷的感觉,避免了长时间的弯腰动作,操作比原先更方便舒适。结论:冷冻切片机防卷板远距操作装置改善了翻动切片机防卷板的工作环境,避免了操作人员的手部受冻,同时也保护了操作人员的腰部,是一种简单、实用的翻动切片机防卷板辅助装置。

Preparation of ^(99m)Tc-PQQE and preliminary biological evaluation for the NMDA receptor

The 4,5-dioxo-4,5-dihydro-1H-pyrrolo(2,3-f)quinoline-2,7,9-tricarboxylic acid 2-ethyl ester 7,9-dimethyl ester (PQQE) was synthesized on the basis of Pyrroloquinoline quinine (PQQ). 99m Tc-PQQE was prepared using stannous fluoride (SnF 2 ) as reducing agent. Biological characteristics of 99m Tc-PQQE include lipophilic and the charge properties were compared to 99m Tc-PQQ. The biodistributions of 99m Tc-PQQE in mice and brain regional distribution were performed. In vivo distribution of 99m Tc-PQQE in mice indicates that the concentration ratio of drug and blood increases steadily over time. The major radioactivity may be metabolized by the hepatic and renal system. The elimination-phase half-time (t1/2β) results indicate that the residence time of 99m Tc-PQQE (203.92) in the body is twice as long as 99m Tc-PQQ (100.45). The uptake of 99m Tc-PQQE in brain was improved due to the ameliorating of charge and lipophilicity. The highest total regional brain uptake of 99m Tc-PQQE was in the frontal lobe and hippocampus, where the NMDA receptor is very abundant. 99m Tc-PQQE had a good target to nontarget ratio (hippocampus/cerebellum) which preserved a higher value (peak 4.0 at 120 min) from 60 min to 180 min after injection. In vitro autoradiographic results are in close agreement with the regional brain map. The enrichment can be blocked by N-methyl-D-aspartate receptor (NMDAR) redox modulatory site antagonists-ebselen (EB). This work suggests that 99m Tc-PQQE has some specific targeting to the NMDA receptor.

Radio-ligand receptor binding assav in vitro and animal biodistribution in vivo of ^(99)Tc^m-N-ethyl-N_2S_2-memantine as a potential NMDA receptor imaging agent

The pharmacologic characteristics of ^(99)Tc^m-N-ethyl-N_2S_2-memantine,an NMDA receptor imaging agent,was investigated.It was prepared by a one-step reaction from N-ethyl-N_2S_2-memantine.The affinity and specificity were determined by radio-ligand receptor binding assay(RRA).Biodistribution in vivo in mice was performed.The results showed that ^(99)Tc^m-N-ethyl-N_2S_2-memantine bound to a single site on NMDA receptor with a K_d of 584.32 nmol/L and a B_(max)of 267.05 nmol/mg.A competitive analysis showed that such specific binding could be inhibited by specific inhibitors of NMDA receptor,such as ketamine and(+)-MK-801.The biodistribution exhibited rapid uptake and favorable retention in mice brains.The major radioactivity was metabolized by the hepatic system.A two-compartment model of C=4.49e^(-0.083t)+ 1.42e^(-0.0016t)was established,and the half life was 8.35 min in blood.In conclusion,the new radio-ligand ^(99)Tc^m-N-ethyl-N_2S_2-Memantine has a moderate affinity and specific binding to NMDA receptor,and can easily cross the blood-brain barrier(BBB).Therefore,it may be a potential NMDA receptor imaging agent.

Animal biodistribution, safety and validation study of dopamine transporter PET imaging agent ^(18)F-FECNT

This work was to investigate the pharmacologic characteristics of 18F-FECNT (2β-carbomethoxy-3β- (4-chlorophenyl)-8-(2-[18F]fluoroethyl)nortropane) as a dopamine transporter (DAT) PET imaging agent. Its partition coefficients were determined in n-octanol and phosphate buffer (PB) (pH 7.0 and pH 7.4). 6-Hydroxydopamine (6-OHDA) left-sided lesioned Parkinsonian rats were established and validated by rotational behavior tests. Biodistribution in vivo in mice, autoradiography in normal and hemi-Parkinsonian rat brains, and toxicity test were performed. The results showed that partition coefficients were 34.14 (pH 7.0) and 56.41 (pH 7.4), respectively. Biodistribution exhibited rapid uptake and favorable retention in the mice brains. The major radioactivity was metabolized by the hepatic system. The autoradiography showed that 18F-FECNT was highly concentrated in striatum, and that the left and the right striatal uptake were symmetrical in normal SD rat brains. In left-sided lesioned PD rat brains, the striatal uptake of 18F-FECNT bilaterally decreased in comparison with normal rats. No significant uptake was visible in the 6-OHDA lesioned-sided striatal areas. The results demonstrated that 18F-FECNT binds to DAT was specific. Toxicity trial displayed that the acceptable dose per kilogram to mice was 625 times greater than that to human. These indicate that 18F-FECNT is a potentially safe and useful DAT PET imaging agent in the brain.