Alpha and gamma motoneurons in the peroneal nuclei of the cat spinal cord: an ultrastructural study.

The aim of the present study was to investigate whether ultrastructural features can be used as a guide to identify alpha- and gamma-motoneurons among the intermediate-size neurons of the peroneal motor nuclei. The peroneus brevis and peroneus tertius muscles of adult cats were injected with horseradish peroxidase, and motoneurons labeled by retrograde axonal transport were examined by electron microscopy. In both nuclei, the distributions of cell-body diameters, measured in the light microscope, were bimodal covering the range of 28-84 microns, with a trough around 50 microns. The sample of 25 motoneurons selected for the ultrastructural study included not only large (presumed alpha) and small (presumed gamma) neurons but also intermediate-size cell bodies with diameters in the 40-60 microns range. For each motoneuron, 2-5 profiles were reconstructed from ultrathin sections taken at 6-8 microns intervals. Synaptic boutons were counted and their lengths of apposition were measured. On the basis of three criteria, namely: (1) bouton types present on the membrane, (2) percentage of membrane length covered by synapses, and (3) the aspect of the nucleolus, all the examined motoneurons, including those with intermediate sizes, fell into one of two categories. Fourteen motoneurons, with cell-body diameters in a range of 55-84 microns, were contacted by all types of boutons (mainly S-type with spherical vesicles, F-type with flattened vesicles, and C-type with subsynaptic cistern); the synaptic covering of the somatic membrane was over 40% and the nucleus contained a vacuolated nucleolus. These were considered alpha-motoneurons. Eleven motoneurons, with only S and F boutons, a synaptic covering under 30%, a compact nucleolus and a cell-body diameter ranging between 28 and 50 microns, were considered gamma-motoneurons. No other combination of the three criteria was observed. These results show that unequivocal distinction of alpha- and gamma-motoneurons is possible in the peroneal nuclei, on the basis of morphological differences independent of cell-body size.     

Postoperative necrotizing sclerokeratitis

The postoperative necrotizing sclerokeratitis is a rare condition occurring shortly after surgical procedures, mainly following cataract extractions. After several exacerbations and remissions spontaneous scleral perforation may occur. In the described case the conservative treatment/topical antibiotics, corticosteroids/failed, therefore the damaged scleral surface was covered with lyophilized dura and the condition came to a standstill.     

非线性动态系统理论在林业系统中的应用——Ⅱ.用信息熵研究林业系统中生态和经济协调关系

用K.S熵(一种信息熵)判别林业系统中生态和经济的协调关系,并提出了控制和改进现有林业系统的有效途径。     

Barium blocks cell membrane and tight junction conductances inNecturus gallbladder epithelium

The site and concentration dependence of the blocking effect of Ba²⁺ onNecturus gallbladder epithelium has been investigated. A new approach was used which combines time-dependent electrical cell coupling analysis with intermittently performed measurements of transepithelial and apparent intracellular impedance. From the coupling pulse data the sum of apical and basolateral membrane conductances is obtained, which is then held constant during fitting of the impedance data. This combination technique yields more reliable estimates of apical and basolateral membranes resistances (R _a,R _bl) and of tight junction resistance (R _j) than our previous impedance analysis technique. Using the new approach we have found that luminal Ba²⁺ concentrations between 0.5 and 1.0 mmol/l increaseR _a with saturation-type kinetics without affectingR _bl andR _j, while higher luminal Ba²⁺ concentrations progressively increaseR _j. Corresponding effects were observed under serosal Ba²⁺. The results validate the new impedance analysis approach and demonstrate that millimolar concentrations of Ba²⁺ block tight junction conductances. Accordingly, Ba²⁺ can no longer be considered a tool to exclusively alter cell membrane resistances in epithelia.     

Distribution of house dust mite allergen: comparing house dust mite allergen levels in dust samples collected from different sites on living room floors with smooth coverings

BACKGROUND: The distribution of house dust mite allergen (Der p1) in living rooms with smooth floor coverings, as measured in the middle compared with the border of the floor was investigated. It was hypothesized that activity causes displacement of Der p1, from the middle towards the border. METHODS: Dust samples from the middle and border of 50 floors with smooth coverings were collected and analysed on Der p1 content in a standardized way. RESULTS: The Der p1 exposure expressed as per unit area (ng/m2) showed that border samples contained significantly more Der p1 compared with middle samples (median: 2.57 vs 0.27, respectively, P = 0.023). Presence of pets and presence of more than two inhabitants increased the difference. When expressed as per unit weight of dust (ng/g), significant differences were only detected when comparing Der p1 content of samples collected in households with three or more inhabitants [median: 2 (border) vs 53 (middle), respectively; P = 0.035]. CONCLUSIONS: The Der p1 is unequally distributed on living room floors with smooth coverings, most likely because of displacement of dust from the middle towards the border due to activity. Expression as ng/g of dust and ng/m2 could not obviously be interchangeable.     

兰西拉光缆工程沿线水源卫生调查

目的 了解青藏线水源水质卫生状况,为施工部队水源选择、洁治消毒提供参考依据。方法 硬度使用ＥＤＴＡ－２Ｎａ进行滴定,其余指标使用８８型检水检毒箱测定。结果施工沿线基本无现成可利用的水源,所调查２２个水源中９个存在生物污染,３个水源氯化物或硫酸盐严重超标;５个水源总铁严重超标。结论 摸清了放工沿线水源水质卫生状况,为部队施工和以后执行任 务时选择水源、进行水质改善提供了科学依据。     

失火烟雾吸入与肺损伤

目的　观察失火烟雾吸入引起肺损伤的表现。方法　对 117例失火烟雾吸入者的临床表现进行分析 ,并进行了相应的大鼠染毒实验。结果　临床上主要表现为上呼吸道和肺部的刺激和炎症反应 ,动脉血氧分压降低。染毒大鼠支气管肺泡灌洗液中细胞总数及中性白细胞数增高 ,磷脂组分改变。病理形态学可见炎症浸润、间质水种及肺水肿。结论　失火烟雾吸入可致急性呼吸道损伤 ,表现为刺激性气道炎、肺泡炎及肺水肿。     

羊膜移植联合结膜瓣遮盖术防止角膜穿孔

目的 探讨羊膜移植联合结膜瓣遮盖术防止角膜穿孔的临床疗效.方法 采用羊膜移植联合结膜瓣遮盖治疗难治性角膜炎致角膜濒临穿孔24例,术后继续局部药物治疗,随访3-10个月,观察角膜愈合情况.结果 术后均未见羊膜植片的急性排斥反应,所有手术病例无一出现角膜穿孔,角膜溃疡逐渐修复,角膜基质有不间程度的增厚,多数患者术后视力均有不同程度的提高.结论 羊膜移植联合结膜瓣遮盖是治疗角膜濒临穿孔的有效方法.     

玻璃体切割联合改良倒置内界膜瓣覆盖及自体血封闭术治疗难治性黄斑裂孔

目的 观察玻璃体切割(PPV)联合改良倒置内界膜(ILM)瓣覆盖及自体血封闭术治疗难治性黄斑裂孔(MH)患者的临床疗效.方法 回顾性病例研究.选取2019年1月至2020年6月在南京医科大学眼科医院确诊并行PPV联合改良倒置ILM瓣覆盖及自体血封闭术治疗的难治性MH患者14例14眼纳入研究.所有入组患者均接受经睫状体扁...     

绿色防火电缆隧道的研究

综述了国内外电缆隧道火灾概况,分析了电缆阻燃防火存在的问题,提出了绿色防火电缆隧道的设计方案,探讨了绿色防火电缆隧道的安全性能、经济效益和环保效果。