猫脑干上涎核节前神经元电活动的观察

在麻醉的32只猫记录了电刺激颌下腺神经支引起的上涎核平均场电位和单位放电。逆行电刺激颌下腺神经支引起的上涎核平均场电位分布在同侧脑干背面闩部头端5.5—8mm处,与过去的组织学结果大致符合。用微电极在上涎核记录了68个对刺激颌下腺神经支有反应的单位,其中33个单位作了碰撞试验。有9个单位符合逆向反应标准,它们是真正的颌下腺节前神经元,逆行反应的潜伏期为14.4±2.5ms,其轴突传导速度为2.9±0.1m/s。其他不符合逆向反应标准的单位,对刺激颌下腺神经支仍能发生反应,估计多为中间神经元。在一部分单位观察了电刺激舌神经或味觉刺激舌引起的反应。根据这些观察对上涎核内存在复杂神经元回路的可能性作了讨论。     

A mathematical model for the burden of diabetes and its complications

Background  

The incidence and prevalence of diabetes are increasing all over the world. Complications of diabetes constitute a burden for the individuals and the whole society.     

A two-dimensional mathematical model of percutaneous drug absorption

Background  

When a drug is applied on the skin surface, the concentration of the drug accumulated in the skin and the amount of the drug eliminated into the blood vessel depend on the value of a parameter, r. The values of r depend on the amount of diffusion and the normalized skin-capillary clearence. It is defined as the ratio of the steady-state drug concentration at the skin-capillary boundary to that at the skin-surface in one-dimensional models. The present paper studies the effect of the parameter values, when the region of contact of the skin with the drug, is a line segment on the skin surface.     

Human tissue kallikrein 9: production of recombinant proteins and specific antibodies

Human tissue kallikreins (genes, KLKs; proteins, hKs) are a subgroup of hormonally regulated serine proteases. Two tissue kallikreins, namely hK2 and hK3 (prostate-specific antigen, PSA), are currently used as serological biomarkers of prostate cancer. Human tissue kallikrein 9 (KLK9) is a newly identified member of the tissue kallikrein gene family. Recent reports have indicated that KLK9 mRNA is differentially expressed in ovarian and breast cancer and has prognostic value. Here, we report the production of recombinant hK9 (classic form) using prokaryotic and mammalian cells and the generation of polyclonal antibodies. Total testis tissue mRNA was reverse-transcribed to cDNA, amplified, cloned into a pET/200 TOPO plasmid vector, and transformed into E. coli cells. hK9 was purified and used as an immunogen to generate polyclonal antibodies. Full-length KLK9 cDNA was also cloned in the vector pcDNA3.1 and was expressed in CHO cells. The identity of hK9 was confirmed by mass spectrometry. hK9 rabbit antiserum displayed no cross-reactivity with other tissue kallikreins and could specifically recognize E. coli- and CHO-derived hK9 on Western blots. hK9 was mainly detected in testis and seminal vesicles by Western blotting. The reagents generated here will help to define the physiological role of this tissue kallikrein and its involvement in human disease.     

Gene doctoring: a method for recombineering in laboratory and pathogenic Escherichia coli strains

Background  

Homologous recombination mediated by the λ-Red genes is a common method for making chromosomal modifications in Escherichia coli. Several protocols have been developed that differ in the mechanisms by which DNA, carrying regions homologous to the chromosome, are delivered into the cell. A common technique is to electroporate linear DNA fragments into cells. Alternatively, DNA fragments are generated in vivo by digestion of a donor plasmid with a nuclease that does not cleave the host genome. In both cases the λ-Red gene products recombine homologous regions carried on the linear DNA fragments with the chromosome. We have successfully used both techniques to generate chromosomal mutations in E. coli K-12 strains. However, we have had limited success with these λ-Red based recombination techniques in pathogenic E. coli strains, which has led us to develop an enhanced protocol for recombineering in such strains.     

清醒猫摄食过程中的胃电活动

本文报告慢性清醒猫正常摄食过程中胃电的变化,以及脑室注射心得安和动物麻醉对胃电的影响。结果显示,空腹饥饿状态下,猫胃电图上出现具有特征性的高振幅的“饥饿波”;摄食时胃电慢波抑制,可见较小快波;进食后半小时左右,胃电开始出现每分钟4—5次的振幅逐渐增大的正弦形慢波,多数慢波负载有快波。脑室注射心得安,可使饱猫胃电慢波抑制期出现饥饿波。动物在饥饿时麻醉,胃电慢波幅度显著降低,饥饿波完全不出现,苏醒后逐渐恢复。