Effect of dopamine content in rat brain striatum on anesthetic requirement: an in vivo microdialysis study

This study investigated the changes in anesthetic requirement caused by administration of two different concentrations (0.1 μM and 1.0 μM/h) of dopamine into the rat striatum. During the measurement of minimum alveolar concentration (MAC), each dopamine solution was continuously injected directly into rat striatum by microdialysis technique. During perfusion of the lower dose, MAC did not change. During the higher dose of dopamine, MAC decreased by approximately 30%.     

关于修订车间空气中三硝基甲苯卫生标准的探讨

目的 对我国现行车间空气中三硝基甲苯卫生标准进行修订。方法 根据现场劳动卫生学调查、流行病学调查、动物实验及剂量－反应关系资料，并参考国外接触限值对三硝基甲苯卫生标准进行修订。结果 我国现行的车间空气中三硝基甲苯卫生标准，最高容许浓度为1.0mg/m^3（皮），职业危害严重，不能有效地保护作业人员的健康。结论 建议将车间空气中TNT的最高容许浓度（MAC）修订为0.5mg/m^3（皮），并制订时间加权平均容许浓度（TWA）为0.2mg/m^3(皮）。     

Microcomputer-assisted transmission of disaster data by cellular telephone

Voice communication of information during disasters is often inadequate. In particular, simultaneous transmission by multiple callers on the same frequency can result in blocked transmissions and miscommunications. In contrast, nonvoice transmission of data requires less time than does voice communication of the same data, and may be more accurate. We conducted a pilot study to test the feasibility of a microcomputer assisted communication (MAC) network linking the disaster scene and the command hospital. The radio chosen to transmit data from the field disaster site to the command hospital was a cellular telephone connected to the microcomputer by modem. Typed communications between the microcomputer operators enabled dialogue between the disaster site and the hospitals. A computer program using commercially available software (Symphony by Lotus, Inc.) was written to allow for data entry, data transmission, and reports. Patient data, including age, sex, severity of injury, identification number, major injuries, and hospital destination were successfully transmitted from the disaster site command post to the command hospital. This pilot test demonstrated the potential applicability of MAC for facilitating transmission of patient data during a disaster.     

Halothane enhances the binding of diazepam to synaptic membranes from rat cerebral cortex

The effects of halothane on diazepam binding to the rat cerebral synaptic membranes were investigated. Halothane at the concentrations of 0.63, 1.3 and 4.1 mmol/l increased the binding by 12, 23 and 33%, respectively, compared to the control in the absence of halothane. The increments were dependent on the presence of Cl-. The findings indicate that halothane and diazepam have an interaction at receptor level.     

补体系统与心肌缺血再灌注损伤

心肌缺血再灌注可使补体系统迅速激活,激活后的补体蛋白经过一系列酶促反应生成攻膜复合物(MAC、C5b-9)、C3a和C5a等补体成分,通过MAC的直接及中性粒细胞的间接损伤作用,导致心肌缺血再灌注损伤的加重,而采用肝素及相关的氨基葡聚糖类(AGA)、补体抑制剂(Cl-INH、sCR-1)和C5a抗体等药物可抑制补体激活级联反应,减轻缺血再灌注损伤。     

一种高可靠的多通道MAC协议

针对工业无线传感器网络的应用需求和射频环境特点,提出了一种高可靠的多通道MAC协议CHNP.协议中给出了一种基于协商模式通道切换机制的MAC架构,并基于该架构给出了一种通道切换模式选择算法和一种自适应传输机制.前者可以实现更高程度的并发传输,而后者可在动态变化的射频条件下自适应地选择高质量通道进行传输.仿真表明,与已有多通道协议相比,CHNP可大幅提高网络的吞吐量、分组到达率以及MAC层延迟性能,并具有更好的抗干扰能力.     

Neuro-modulation, aminergic neuro-disinhibition and neuro-degeneration. Draft of a comprehensive theory for Alzheimer disease

A comprehensive theory for Alzheimer disease (AD) which can provide a clue to the neuronal selective vulnerability (pathoklisis) is still missing. Based upon evidence from the current literature, the present work is aimed at proposing such a theory, namely the 'aminergic disinhibition theory' of AD. It includes data-based hypotheses as to the pathoklisis, mechanisms of neuro-degeneration and dementia as well as the aetiology of the disease. Alzheimer disease is regarded as a disorder of neural input modulation caused by the degeneration of four modulatory amine transmitter (MAT) systems, namely the serotoninergic, the noradrenergic, the histaminergic, and the cholinergic systems with ascending projections. MATs modulate cognitive processing including arousal, attention, and synaptic plasticity in learning and memory, not only through direct, mostly inhibitory impact on principal neurones but also partially through interaction with local networks of GABA-ergic inter-neurones. The distribution and magnitude of the pathology in AD roughly correlate with the distribution and magnitude of MAT modulation: Regions more densely innervated by ascending MAT projections are, as a rule, more severely affected than areas receiving less MAT innervation. Because the global effect of MATs in the forebrain is inhibition, the degeneration of four MAT systems, some related peptidergic systems and a secondary alleviation of the GABA-ergic transmission means a fundamental loss of inhibitory impact in the neuronal circuitry resulting in neuronal (aminergic) disinhibition. Clearly, the basic mechanism promoting neuronal death in AD is thought to be a chronic disturbance of the inhibition-excitation balance to the advantage of excitation. Chronic over-excitation is conceived to result in Ca2+ dependent cellular excito-toxicity leading to neuro-degeneration including amyloid-beta production and NFT formation. Disinhibited neurons will degenerate while less excited (relatively over-inhibited) neurones will survive. Because the decline of aminergic transmission in AD is likely to start at the receptor level, it is hypothesized that early impairment by a molecular 'hit' to an MAT receptor (or a group of receptors) initiates a pathogenetic cascade that develops in an avalanche-like manner. Based on experimental evidence from the literature, the 'hit' might be the attachment of a targeted pathogen like a small roaming amino acid sequence to the receptor(s), e.g., the serotoninergic 5-HT2A-R. Referential sequence analysis could be a means to identify such a small pathogen hidden in a large receptor molecule.     

Completely converting a blood service region to the use of safer plasma

BACKGROUND: Three types of plasma are widely available for transfusion. Two plasma components, FFP donor retested (FFP-DR), and solvent/detergent-treated plasma (SDP), are now considered to be safer from infectious complications than FFP. STUDY DESIGN AND METHODS: A large regional blood center attempted to provide FFP-DR exclusively to all its 42 hospitals. Significant planning, increases in computer capabilities, and expansion of component storage areas were completed before initiation of this program. RESULTS: During the first 6 months of the FFP-DR program, the blood center was not able to supply the entire region exclusively with FFP-DR. Consequently, SDP was utilized to supplement the program and to successfully and completely convert the region's 42 hospitals to the use of safer plasma. CONCLUSION: Two new plasma components were utilized to completely convert a blood service region to the use of safer plasma.     

Acute,subacute and subchronic inhalation toxicity of cyclopentene

Summary Cyclopentene was evaluated for its acute, subacute and subchronic inhalation toxicity. The LC₅₀ values for male and female rats after 4-hr inhalation of cyclopentene vapours are higher than 8110 ppm. The daily exposure of rats to concentrations of 870 and 8110 ppm for 6 hrs/day, 5 times/week for 3 weeks resulted only in decreased body weight gains of the female animals exposed to concentrations of 8110 ppm. Male and female rats were exposed to daily concentrations of 112, 317 or 1139 ppm for 6 hrs/day, 5 times/week for 12 weeks. These concentrations were tolerated without any detectable toxicological effects. Short-term exposure of humans revealed a tolerable concentration of 10–15 ppm only. The results are discussed in relation to the possibility of establishing a maximal allowable concentration.We wish to express our thanks to Miss Anneliese Eben for the determinations of the concentrations in the air.