大鼠正中神经感觉纤维在脊髓胶状质定位投射的定量分析

目的　对大鼠正中神经感觉秒纤维在脊髓胶状质 (SG)的定量投射进行定量分析。方法　按照跨神经节溃变的原理 ,用抗氟化物酸性磷酸酶 (FRAP)法和显微测量。结果　大鼠正中神经向SG的纵向投射主要为C5～T1。C5～T1各节段SG水平向眉毛状反应带所测均值 (mm)分别为 0 888、0 935、0 95 7、0 90 5和 0 776 ,而正中神经向C5～T1各节段SG水平向投射所测均值 (mm)分别在 0～ 0 2 0 4、0～ 0 30 3、0～ 0 4 0 9、0～ 0 4 32和 0～ 0 336的范围。结论　结果显示正中神经投射区均位于SG的内侧带和部分中间带     

杭州地区8516例孕中期妇女产前筛查回顾性分析

目的分析杭州地区孕中期妇女运用甲胎蛋白(AFP)和游离绒毛膜促性腺激素β亚基(Free-βhCG)进行胎儿先天缺陷产前筛查的结果;并据此修正两筛查指标的孕周中位数值。方法对杭州地区孕14~20w的妇女进行产前AFP和Free-βhCG的检测。胎儿先天畸形由染色体核型分析、B超检查确诊,或经引产证实。应用非线性加权回归求得本地区两筛查指标的中位数,并计算中位倍数值进行分布拟合。比较标化前后检测效果。结果8516例受检孕妇,共筛查出唐氏综合征3例、爱德华综合征2例,神经管畸形7例,其他胎儿异常17例;杭州地区孕中期妇女AFP及Free-β-hcG中位数比欧洲妇女分别高18%和14%;用修正后的中位数重新分析,孕中期假阳性率降低。结论血清AFP、Free-βhcG联合检测,可作为杭州地区孕中期妇女产前筛查优选项目。而根据地域人群的差异,对Mu ltiCalc软件内嵌中位数进行修正后更适于杭州地区孕中期妇女的产前筛查。     

Involvement of the median preoptic nucleus in the regulation of paraventricular vasopressin neurons by the subfornical organ in the rat

Summary Extracellular recordings in urethane-anesthetized male rats indicated that electrical stimulation of the subfornical organ (SFO) alters the activity of 54 out of 62 phasically firing neurosecretory neurons in the hypothalamic paraventricular nucleus (PVN); 44 cells demonstrate an increase in excitability; 10 cells display a depression in their activity. In 14 out of 38 PVN cells tested, SFO stimulation-evoked excitations were abolished by pretreatment with the angiotensin II (ANG II) antagonist, saralasin (Sar), in the region of the median preoptic nucleus (MnPO). Inhibitory responses (n=7) were not affected. Microinjection of ANG II into the region of the SFO produced either a facilitation (n=28) or no effect (n=6) on the excitability of phasically active PVN neurosecretory cells and the facilitatory effect of 9 out of 23 cells tested was prevented by pretreatment with Sar in the region of the MnPO. All the PVN cells which had excitatory responses to either electrical (n=7) or chemical (n=9) stimulation of the SFO that were blocked following the pretreatment could also be activated by intravenous administration of ANG II. Furthermore, this activation was blocked (n=10) or attenuated (n=6) by pretreatment with Sar in the region of the MnPO. These results show an involvement of both the MnPO and the SFO for the regulation of excitability of putative vasopressin (VP)-secreting PVN neurons, and suggest that MnPO neurons sensitive to ANG II may relay activation of SFO neurons by circulating ANG II to putative VP-secreting PVN neurons which result in enhanced excitability.     

5-HT mechanisms of median raphe nucleus in the conditioned freezing caused by light/foot-shock association

We have shown that 5-HT mechanisms of the median raphe nucleus (MRN) are involved in contextual fear-conditioning processes as electrolytic or neurotoxic lesions with N-methyl-D-aspartate (NMDA) or injections of 8-hydroxy-2-(di-n-propilamino)-tetralin (8-OH-DPAT) into this structure inhibit freezing behavior in a contextual fear paradigm. In this work, we extend these studies by analyzing the behavioral responses in a classical fear-conditioning paradigm (light or tone/foot-shock association) in rats with either neurochemical lesion with NMDA or injected with 8-OH-DPAT into the MRN. The animals received NMDA or 8-OH-DPAT or saline microinjections into the MRN and were submitted to conditioning trials in an experimental chamber, where they received 10 foot-shocks (0.6 mA, 1 s, variable interval between 10 and 50 s) paired with tone or light (CS). On the next day, they were tested in a different experimental chamber, with or without CS presentation, where the duration of freezing and the number of rearing episodes were recorded. Light or tone alone caused a significant amount of freezing. NMDA lesions or 8-OH-DPAT injections into the MRN clearly inhibited freezing behavior in rats conditioned to light/foot-shock association, but not in the conditioning sessions with tones. Besides the proposed role in contextual fear conditioning, these results clearly show that MRN is involved in the fear conditioning with light as conditioned stimuli. Distinct neural substrates seem to subserve conditioning fear with acoustic stimuli.     

Subfornical organ and hypothalamic paraventricular nucleus connections with median preoptic nucleus neurons: an electrophysiological study in the rat

Summary The role of pathways from the subfornical organ (SFO) to the hypothalamic paraventricular nucleus (PVN) through the median preoptic nucleus (MnPO) in regulating the activity of putative vasopressin (VP)-secreting neurons in the PVN was examined in urethane-anesthetized male rats. The activity of the majority (79%) of SFO neurons antidromically identified as projecting to the MnPO was excited by microiontophoretically (MIPh) applied angiotensin II (ANG II) and the effect was blocked by MIPh-applied saralasin (Sar), an ANG II antagonist. Identified SFO neurons that were excited by MIPh-applied ANG II were also excited by intravenously administered ANG II. Electrical stimulation of the SFO produced orthodromic excitation (48%) or inhibition (24%) of the activity of MnPO neurons antidromically identified as projecting to the PVN. Identified MnPO neurons that were excited by SFO stimulation were also excited by MIPh-applied ANG II, while the remaining neurons were not affected. The excitatory responses to SFO stimulation and to MIPh-applied ANG II were both blocked by MIPh-applied Sar, whereas the inhibitory responses to SFO stimulation were not affected. ANG II injected into the region of the SFO produced either an excitation (55%) or no effect (45%) on the activity of identified MnPO neurons. Electrical stimulation of the MnPO produced orthodromic excitation (27%) or inhibition (23%) of the activity of putative VP-secreting PVN neurons. ANG II injected into the region of the MnPO produced either an excitation (31%) or no effect (69%) on the activity of putative VP-secreting PVN neurons. These observations reveal some possible interconnections between three brain regions and suggest that circulating ANG II excites a population of neurons projecting from the SFO to the MnPO, and that these neurons themselves release ANG II as an excitatory transmitter on part of MnPO neurons projecting to the PVN, thereby causing enhanced activity of putative VP-secreting PVN neurons.     

Relationships between muscle lactate accumulation and surface EMG activities during isokinetic contractions in man

Summary In order to investigate the relationship between metabolic state and myoelectrical activity in working muscle during short term intense exercise, eleven healthy males performed isokinetic knee extensions at an angular velocity of 180 deg · sec^–1 for 30 and 60 s. The median frequency (MF) of the surface electromyogram (EMG) recorded from vastus lateralis was decreased while the time lag of torque production after the onset of electrical activity (EMD) was increased during exercise. These changes (MF and EMD) corresponded well to muscle lactate accumulation in the same muscle. Over the exercise period, the integrated EMG/knee extension peak torque ratio (E/T ratio) was increased, which indicated a decrease in the efficiency of electrical activity. It was concluded that the changes in the frequency components of the EMG and in the contractile property of the muscle during short term intense exercise correlated with lactate accumulation in the identical muscle, and that the decrease in efficiency of the electrical activity in the muscle suggested peripheral fatigue.     

亚稀褶红菇对大鼠致死毒性分级研究

目的 为了解亚稀褶红菇对大鼠的半数致死量（LD50）,进行毒性分级。方法 采用急性毒性试验经典方法寇氏法,设亚稀褶红菇175、248、350、495、700 mg/kgBW共 5个剂量组和阴性对照组(等体积生理盐水),每组大鼠12只,雌雄各半,腹腔注射,连续观察14 d大鼠的毒性反应和死亡情况。并对试验大鼠进行病理组织学检查。结果 根据试验结果,经计算,亚稀褶红菇对SD大鼠腹腔注射LD50为406 mg/kgBW,95%可信限为348～473 mg/kgBW。病理学检查显示大鼠心脏、肝脏、肾脏均有损害,随剂量增加损害程度加重。结论 按照大鼠急性毒性（LD50）剂量分级亚稀褶红菇为中等毒性,相当于人的致死量为5 g/人。     

"Y"型或"I"型部分胸骨切口行心内直视手术30例

目的介绍经"Ｙ"型或"Ｉ"型部分胸骨切口行心内直视手术的体会。方法取下１／２～２／３胸部正中皮肤切口,纵行劈下２／３胸骨使呈"Ｙ"型或"Ｉ"型,体外循环直视下行心内直视手术３０例,其中二尖瓣置换９例,二尖瓣成形２例,法乐四联症矫治１１例,室间隔缺损修补８例。结果全部病例无手术死亡及并发症。疤痕长度仅为胸骨正中切口的６０％左右。结论"Ｙ"型或"Ｉ"型部分胸骨切口可安全有效地完成大部分心脏疾病的手术,创伤的程度及术后美容效果明显优于胸骨正中切口,手术适应症的范围明显大于右胸小切口。