Involvement of GABA in medullary raphe-evoked modulation of neuronal activity in the periaqueductal grey matter in the rat

Experiments were carried out in urethane-anaesthetised rats to investigate whether GABA is involved in mediating inhibition of neuronal activity in the dorsal half of the periaqueductal grey matter (PAG) after stimulation of the serotonin-containing projection to the PAG from nucleus raphe obscurus (NRO). Multibarrelled micropipettes were used to make recordings from 42 neurones in the dorsal half of the PAG. Most (n = 36) cells were quiescent. Their firing rate was therefore raised to 10-16 Hz by continuous iontophoretic application of DL-homocysteic acid (DLH) in order to facilitate the study of inhibitory events. Iontophoretic application of GABA (0-10 nA) silenced every neurone tested (n = 42), and the effect was blocked by the GABAA antagonist bicuculline (BIC, 10-20 nA; 15/15 cells). BIC also produced an increase in ongoing activity in 14 of 15 cells, indicating the presence of inhibitory GABAergic tone. Iontophoretically applied serotonin (5-HT; 10-70 nA) also inhibited ongoing activity in 9 of 11 cells. The effect of 5-HT was not blocked by BIC. In six of seven cells, microinjection of 100-200 nl DLH into NRO produced a 72.3 +/- 9.4% decrease in neuronal firing rate which was maximal 112 +/- 18 s after the start of the injection and lasted for a total of 313 +/- 63 s. In five of six cells, the raphe-evoked inhibition was blocked by BIC. It is suggested that activation of the serotonergic projection to the PAG from NRO engages GABA-containing interneurones within the PAG which mediate the inhibitory effects of raphe stimulation.     

Excision of a recurrent mediastinal cyst through mid sternotomy with high thoracic epidural anesthesia as the sole anesthetic—A case report

Conclusion Our case report highlights the possibility of tackling mediastinal, pericardial and pleural problems with regional anesthesia alone even if the surgery requires opening of the pleura.     

公共产品价格机制及价格约束分析

公共产品涉及千家万户的切身利益，近10多年来，部分公共产品价格变化又多以超过国民经济发展速度提高，怎样正确认识和判断其价格的合理性，具有十分重要的现实意义。本文分析了我国公共产品的价格类型，定价机制，阐明了我国公共产品的价格约束制度构建的主要内容，希望为政府及相关部门工作提供有益的帮助。     

PBL在病原生物与免疫学教学中的实践

目的探讨病原生物与免疫学教学中开展PBL教学的效果。方法对照组采用传统的教学方法，实验组采用PBL教学方法，通过问卷调查、考试成绩综合分析教学改革效果。结果实验班绝大多数学生接受并欢迎PBL教学模式，并在自学能力、理解能力、分析解决问题能力等方面得到明显的提高。结论PBL教学方法优于传统的教学方法，能有效提高病原生物与免疫学教学质量。     

Differential Activation of the Periaqueductal Gray by Mild Anxiogenic Stress at Different Stages of the Estrous Cycle in Female Rats

The effect of acute exposure to mild anxiogenic stress on cutaneous nociceptive threshold was investigated in female Wistar rats at different stages of the estrous cycle. Baseline tail flick latencies did not change significantly during the cycle. However after brief exposure to vibration stress (4 Hz for 5 min), rats in late diestrus, but not at other cycle stages, developed a hyperalgesia (decrease in tail flick latency). Animals in late diestrus revealed a more than fivefold increase in the density of Fos-like immunoreactive nuclei in the dorsolateral, lateral, and ventrolateral columns in the caudal half of the periaqueductal gray matter (PAG). There was no change in the density of Fos-like immunoreactive nuclei in the PAG in rats in estrus and early diestrus, although rats in proestrus showed a smaller (50%) but significant increase. Rats undergoing withdrawal from a progesterone dosing regimen (5 mg/kg i.p. twice daily for 6 days) designed to mimic the fall in progesterone that occurs naturally during late diestrus, exhibited a stress-induced hyperalgesia that was similar to animals in late diestrus and a significant increase in Fos-positive cells in the PAG. We suggest that falling levels of progesterone during late diestrus may be a predisposing factor for the development of stress-induced hyperalgesia, which is linked to differential activation of descending pain control circuits in the PAG. Similar changes in women, when progesterone levels fall during the late luteal phase of the menstrual cycle, may contribute to the development of premenstrual symptoms that include increased anxiety and hyperalgesia.     

淋巴靶向制剂——吸附抗癌药毫微粒活性炭的研究进展

目的介绍新型淋巴靶向制剂———吸附抗癌药毫微粒活性炭的研究进展。方法依据近年来的文献 ,对活性炭的制备工艺及体内外性质等方面进行了综述。结果活性炭具有很强的吸附功能 ,普通市售活性炭仅用作脱色、吸附热原与除味等。以微粒球磨机为粉碎器械 ,可加工制备粒径达1 0 0nm左右的纳米炭微粒 ,具有优越的淋巴趋向性。结论吸附抗癌药毫微粒活性炭在临床治疗癌症方面具有良好的运用前景     

Cervicogenic headache

Eleven female patients with cervicogenic headache (mean age, 43 years; range, 25-59 years) have been examined with the pupillometer. The pupillary diameter was examined in the basal state (that is, the status before pharmacologic stimulation) and after topically administered tyramine (2%), phenylephrine (1%), and hydroxyamphetamine (1%). A total of 51 tests were performed, 35 in the asymptomatic period and 16 during pain attacks. In a control group consisting of 26 age-matched women a total of 39 tests were carried out. Before pharmacologic stimulation (that is, in the "basal state") the pupils were smaller in the asymptomatic (pain-free) period than during pain attacks in the patients and also as compared with that of control individuals. The anisocoria (the difference in pupillary size in the same individual) observed was not significantly different between the patient group and control individuals either in the basal state (before pharmacologic stimulation) or after pharmacologic stimulation. The mydriasis resulting from the instillation of the three sympathicomimetic drugs was symmetrical in both controls and patients both during and between the pain attacks. This finding is in clear contrast to what is found in cluster headache, in which there is a "Horner-like" syndrome on the symptomatic side. These two headaches thus seem to differ essentially with regard to this variable.