Recommendations for the Conduct of Acute Inhalation Limit Tests

This paper reviews the scientific issues related to exposureconcentrations and particle sizes used in acute inhalation limittests. The current United States Environmental Protection Agency(USEPA) recommended exposure concentration for such tests is5 mg/liter, while this level is very high, it is often achievable.On the other hand, its toxicological relevance is questionable.The USEPA recommendation that 25% of the particle distributionbe less than 1 µm is a more difficult issue to address.Physical laws for aerosol particle generation and behavior limitthe minimum size of particles in an exposure atmosphere at aconcentration of 5 mg/liter. Particle size also influences depositionsite in the respiratory tract. Since damage to any region ofthe respiratory tract can produce lethality, and it is not possibleto predict, a priori, the most responsive region of the tractor the most harmful particle size of an untested agent, acutelimit testing should employ particles in a size range that depositsthroughout the entire rodent respiratory tract. Particles between1 and 4 µm mass median aerodynamic diameter (MMAD) arewell suited for such studies. It is, therefore, recommendedthat the limit test concentration should be the highest concentration(up to 5 mg/liter) that can be achieved while still maintaininga particle size distribution having an MMAD between 1 and 4µm.     

中医疲劳术语整理研究

以疲劳术语系列中的“倦类”为代表进行释义并阐述了整理疲劳术语的意义的目的。其意义和目的为：阐明中医疲劳的病因，病机，规范描述疲劳的术语，为探讨中医抗疲劳及调治亚健康的方药提供线索与依据。     

Improved outcome of chronic Pseudomonas aeruginosa lung infection is associated with induction of a Th1-dominated cytokine response

Repeated challenge with antigen is involved in the pathogenesis of a variety of pulmonary diseases. Patients with cystic fibrosis (CF) experience recurrent pulmonary colonization with Pseudomonas aeruginosa before establishment of chronic lung infection. To mimic recurrent lung infections in CF patients, the lungs of susceptible BALB/c mice were re-infected with P. aeruginosa 14 days after the initial infection. Singly-infected BALB/c mice, as well as non-infected mice, were used as controls. Decreased mortality and milder lung inflammation in re-infected BALB/c mice, as well as a tendency for improved clearance of bacteria, was observed when compared with singly-infected mice. The improved outcome in re-infected mice correlated with changes in CD4 cell numbers. Surface expression of LFA-1 on pulmonary CD4 cells was increased in re-infected compared with singly-infected mice. Moreover, resistance to re-infection was paralleled by a shift towards a Th1-dominated response and increased IL-12 production. No significant increase in serum IgG was observed in the re-infected mice. In conclusion, these results indicate a protective role for a Th1-dominated response, independent of antibody production, in chronic P. aeruginosa lung infection in CF.     

Effects of oxytocin microinjected into the central amygdaloid nucleus and bed nucleus of stria terminalis on maternal aggressive behavior in rats

The central effect of oxytocin (OT) on the aggressive behavior of lactating rats was studied. Female rats are more aggressive than nonlactating resident females, vigorously attacking conspecific intruder male or females. This behavior is considered important for pup protection against infanticide. The present work aimed to test the effects on maternal aggressive behavior of OT infused into the central amygdaloid nucleus (CeM) or bed nucleus of stria terminalis (BNST). The surgeries for bilateral cannula implantation were performed between the 2nd and 4th postpartum day. Three days after the surgery, saline or OT was infused and 5 min later a male intruder was placed in the home-cage and the behaviors were videotaped for 10 min. The frequency of the aggressive behaviors and the duration of locomotion during the aggressive behavior test were measured. The latency to retrieve the pups was also evaluated. The results showed that OT injected into CeM (10 and 20 ng/nucleus) decreased frequency of biting and frontal attack while in the BNST (10 and 20 ng/nucleus) decreased the frequency of biting. No significant change on retrieval activity was detected. OT in CeM and BNST has an inhibitory effect on the aggressive behavior of lactating female rats.     

Radiochromic film dosimetry of a low energy proton beam

In this work some dosimetric characteristics of MD-55-2 GafChromic films were studied in a low energy proton beam (21.5 MeV) directly in a water phantom. The nonlinearity of the optical density was quantified by a factor P(lin). A correction factor P(en), that accounts for optical density dependence on the energy, was empirically determined. The effects of detector thickness in depth dose measurements and of the film orientation with respect to beam direction were investigated. The results show that the MD-55-2 films provide dose measurements with the films positioned perpendicularly to the proton beam. A dosimetric formalizm is proposed to determine the dose to water at depth d, with films oriented perpendicularly to the beam axis. This formalism uses a calibration factor of the radiochromic film determined directly on the proton beam at a reference depth in water, and the P(lin) factor, that takes into account the nonlinearity of the calibration curve and the P(en) factor that, in turn takes into account the change of proton beam energy in water. The MD-55-2 films with their high spatial resolution and the quasiwater equivalent material are attractive, positioned perpendicularly along the beam axis, for the absolute dose determination of very small beam sizes and modulated proton beams.     

中药肛滴在治疗消化道恶性肿瘤中的应用

探讨中药肛滴在治疗消化道恶性肿瘤中的应用。通过对６例典型病例的回顾分析,观察中药肛滴在缓解癌性粘连性肠梗阻、缓解消化道恶性肿瘤患者症状、提高晚期消化道恶性肿瘤患者生存质量的作用。应用中医理论“通则不痛”之说,对消化道恶性肿瘤患者进行中药肛滴治疗．认为有较好的临床效果。