大鼠侧脑室注射精氨酸加压素对针刺镇痛的影响

以钾离子透入法引起大鼠甩尾反应为指标,测定动物的痛阈。由侧脑室注射精氮酸加压素(AVP)后,大鼠痛阈升高33.6％～68.5％,针刺镇痛效应明显加强,痛阈提高202.4％～302.7％。脑室注射抗精氨酸加压素血清,动物痛阈虽无明显变化,但针刺镇痛效应明显削弱,痛阈仅增加41.6％～71.0％。注射抗β-内啡肽血清和抗强啡肽A血清并不阻断AVP增强针刺镇痛效应。本工作的结果提示,脑内AVP参与针刺镇痛,这种作用与脑内内源性β-内啡肽和强啡肽的关系不甚密切。     

Current-voltage curve of electrogenic Cl− pump predicts voltage-dependent Cl− efflux inAcetabularia

Summary The current-voltage relationship of carrier-mediated, passive and active ion transport systems with one charge-carrying pathway can exactly be described by a simple reaction kinetic model. This model consists of two carrier states (one inside, one outside) and two pairs (forwards and backwards) of rate constants: a voltage-dependent one, describing the transport of charge and a voltage-insensitive one, summarizing all the other (voltage-independent) reactions. For the electrogenic Cl^– pump inAcetabularia these four rate constants have been determined from electrical measurements of the current-voltage relationship of the pump (Gradmann, Hansen & Slayman, 1981;in: Electrogenic Ion Pumps, Academic Press, New York). The unidirectional Cl^– efflux through the pump can also be calculated by the availiable reaction kinetic parameters.³⁶Cl^– efflux experiments on singleAcetabularia cells with simultaneous electrical stimulation (action potentials) and recording, demonstrate the unidirectional Cl^– efflux to depend on the membrane potential. After subtraction of an efflux portion which bypasses the pump, agreement is found between the measured flux-voltage relationship and the theoretical one as obtained from the reaction kinetic model and its parameters from the electrical data.     

The major growth current through lily pollen tubes enters as K+ and leaves as H+

Growing lily (Lilium longiflorum Thunb.) pollen always drive a current into their tubes and out of their grains. The only external ions needed for growth (and the growth current) are K⁺, H⁺, and Ca²⁺. Increases in K⁺ immediately stimulate the current; while decreases in K⁺ immediately inhibit it. Comparable changes in H⁺ have the opposite effect; while those in Ca²⁺ have very little effect. We infer that most of the steady growth current is carried in by a potassium leak and out by a proton pump; but other considerations indicate that a minor, but controlling, component of the inward current consists of calcium ions.     

Studies on normal human bone marrow cultures in controlled environment thin-film culture systems

Summary Two thin film culture systems, the controlled environment steady state system (SS) and the rocker tube configuration of that system (RT), were used to identify some of the conditions that appear to maintain morphologic and functional characteristics of cells of human bone marrow explants in vitro. The systems configuration assured continual gassing, control and easy monitoring of the cultures. Cytocentrifuge preparations of media of specimens cultured in RT disclosed, though in decreasing numbers, various hematopoietic cells for periods exceeding one month. Hematopoietic cells shed from specimens cultured in the SS system were retained in the culture tubes; cells of the myelocytic series predominated for the first 2 weeks while an increasing number of monocytes and macrophages appeared in the media of older cultures. Histologic examination of cultured explants disclosed preservation of the marrow architecture and the persistence of hematopoietic cells. Specimens cultured in RT tubes tended to be less cellular than similar cultures placed in dialysis bags or as cultured in the SS system. Immunoglobulins (Ig) were released into the culture media at a constant rate throughout the period of culture. Specimens that were cultured at a controlled pH of 7.4 released 2 to more than 4 times as much Ig as similar specimens maintained at a pH level of 7.1. There were no definitive differences in Ig levels in the cultures maintained at comparable pH levels and overlaid with various CO₂ concentrations, i.e. 2%, 5%, 10%; similarly, no differences in Ig levels were found in specimens cultured in media containing fetal bovine sera as opposed to horse sera. Supported by U.S.P.H.S. Grant CA-5834 from the National Cancer Institute. Department of Medicine A. Department of Cell Physiology Department of Immunology and Immunochemistry.     

Isolation of Thiomonas thermosulfatus Strain 51, a Species Capable of Coupling Biogenic Pyritization with Chemiosmotic Energy Transduction

The precipitation of iron sulfides potentially offers enough energy and reducing power to sustain life but organisms harnessing this reaction have not to our knowledge been previously described. We isolated a bacterial strain, capable of forming the iron sulfide minerals troilite (FeS), greigite (Fe₃S₄), and pyrite (FeS₂), from subsurface, microbial mats in Mangalia, Romania. This strain, most closely related to strains of Thiomonas sp., forms pyrite only if the redox conditions remain negative (< ?60 mV), sulfides are provided continually (≈1 mM), and the concentration of iron remains low (≤ 0.08 mM) but constant. Pyrite formation by this microbial strain is proposed as an example of biologically controlled mineralization because it is controlled by uncouplers of oxidative phosphorylation, it is larger in living than in dead cells, it is additive (controlled less by the amount of cell surfaces and more by reagents), and it results in the formation of ATP. This study indicates that precipitation and crystal formation can represent an energy resource for life and provides support for the “iron-sulfide world hypothesis” regarding the early evolution of life on Earth.     

MsrA Efflux Pump Inhibitory Activity of Piper cubeba L.f. and its Phytoconstituents against Staphylococcus aureus RN4220

MsrA, an efflux pump belonging to ATP‐binding cassette (ABC) transporter family that conferred resistance to macrolides, was detected in Staphylococcus aureus strains. Herein, we report the isolation of phytoconstituents from Piper cubeba fruit methanol extract and investigated their efflux pump inhibitory potential against S. aureus MsrA pump. Four isolated compounds, viz. pellitorine, sesamin, piperic acid and tetrahydropiperine studied in combination with erythromycin in S. aureus RN4220, exhibited 2–8‐fold reduction in minimum inhibitory concentration (MIC) of erythromycin. Pellitorine and sesamin decreased MIC of erythromycin by 8‐fold. The real‐time fluorometry‐based efflux and accumulation studies of ethidium bromide (EtBr) on S. aureus RN4220 in the presence of these compounds showed reduced efflux and enhanced uptake, thus indicating inhibition of the efflux pump. Pellitorine showed significant post‐antibiotic effect of erythromycin. The results revealed that the primary mechanism of action of these compounds involves steady ATP production impairment.     

胃底腺息肉与胃增生性息肉的临床、内镜特征分析

目的:分析胃底腺息肉与胃增生性息肉的临床、内镜下等特点。方法:回顾性搜集胃镜检出的经病理证实的胃底腺息肉和胃增生性息肉393例纳入分析,按年龄、性别、发生部位、大小、幽门螺杆菌(helicobacter pylori)感染状态、是否使用质子泵抑制剂(proton pump inhibitor)等因素进行分析比较。结果:393例增生性息肉与胃底腺息肉中,男178例,女215例,男女比例为1:1.2,年龄28~89岁。随着年龄的增高,胃息肉发生率越高,但各年龄段分布差异无统计学意义(P>0.05)。不同部位的增生性息肉与胃底腺性息肉大小相比差异有统计学意义(P<0.05)。两种胃息肉的性别分布差异有统计学意义(P<0.05)。增生性息肉H.pylori感染率较胃底腺性息肉高(P<0.05),而胃底腺息肉质子泵抑制剂使用率较胃增生性息肉高(P<0.05)。结论:增生性息肉与幽门螺旋杆菌感染有关,胃底腺息肉与质子泵抑制剂使用有关。对胃底腺息肉与胃增生性息肉的临床、内镜特点的分析有助于胃镜检查对胃息肉性质的初步判断,提高诊断的准确性。     

尺神经原位松解术与尺神经皮下前置术治疗肘管综合征近期疗效比较的回顾性研究

目的:比较尺神经原位松解术与尺神经皮下前置术治疗肘管综合征(CuTS)近期疗效。方法:本研究为回顾性研究,选取2016年7月～2017年7月期间我院二部收治的60例CuTS患者,根据手术方式的不同分为A组(n=32,尺神经原位松解术)和B组(n=28,尺神经皮下前置术),比较两组患者优良率、并发症、围术期指标、感觉运动功能(肌力、小指指端两点辨别觉、神经传导速度)以及DASH上肢功能障碍(DASH)评分。结果:B组术后12个月的优良率为92.86%(26/28),高于A组的68.75%(22/32)(P0.05)。两组术后并发症总发生率比较差异无统计学意义(P0.05)。两组术后12个月肌力、神经传导速度升高,且B组高于A组(P0.05),两组术后12个月小指指端两点辨别觉降低,且B组低于A组(P0.05)。两组术后3个月、术后6个月、术后12个月DASH评分呈下降趋势,且B组低于A组(P0.05)。B组手术切口长度、手术时间长于A组(P0.05),两组术后住院时间比较差异无统计学意义(P0.05)。结论:与尺神经原位松解术相比,尺神经皮下前置术治疗CuTS患者,虽然手术切口长度、手术时间相对较长,但其优良率更高,同时可有效恢复患者感觉运动功能及减轻其上肢功能障碍,且不增加并发症发生率,具有一定的临床应用价值。     

Variation in the phenology of photosynthesis among eastern white pine provenances in response to warming

In higher‐latitude trees, temperature and photoperiod control the beginning and end of the photosynthetically active season. Elevated temperature (ET) has advanced spring warming and delayed autumn cooling while photoperiod remains unchanged. We assessed the effects of warming on the length of the photosynthetically active season of three provenances of Pinus strobus L. seedlings from different latitudes, and evaluated the accuracy of the photochemical reflectance index (PRI) and the chlorophyll/carotenoid index (CCI) for tracking the predicted variation in spring and autumn phenology of photosynthesis among provenances. Seedlings from northern, local and southern P. strobus provenances were planted in a temperature‐free‐air‐controlled enhancement (T‐FACE) experiment and exposed to ET (+1.5/3°C; day/night). Over 18 months, we assessed photosynthetic phenology by measuring chlorophyll fluorescence, gas exchange, leaf spectral reflectance and pigment content. During autumn, all seedlings regardless of provenance followed the same sequence of phenological events with the initial downregulation of photosynthesis, followed by the modulation of non‐photochemical quenching and associated adjustments of zeaxanthin pool sizes. However, the timing of autumn downregulation differed between provenances, with delayed onset in the southern provenance (SP) and earlier onset in the northern relative to the local provenance, indicating that photoperiod at the provenance origin is a dominant factor controlling autumn phenology. Experimental warming further delayed the downregulation of photosynthesis during autumn in the SP. A provenance effect during spring was also observed but was generally not significant. The vegetation indices PRI and CCI were both effective at tracking the seasonal variations of energy partitioning in needles and the differences of carotenoid pigments indicative of the stress status of needles. These results demonstrate that PRI and CCI can be useful tools for monitoring conifer phenology and for the remote monitoring of the length of the photosynthetically active season of conifers in a changing climate.