Hypothalamic hypoactivity prevented but not reversed by subdiaphragmatic vagotomy

Parasagittal hypothalamic knife cuts produce a syndrome which includes obesity and hypoactivity. When the subdiaphragmatic vagi were cut at the same time as the brain cuts were made, both the obesity and the hypoactivity were prevented. This suggested that both the obesity and the hypoactivity are mediated by vagal hyperactivity. In contrast, however, when the subdiaphragmatic vagotomy was done 40–70 days subsequent to the brain cuts, the obesity was reversed, but the hypoactivity persisted. Thus, some aspect of the interoperative period irreversibly prevents the ability of vagotomy to reinstate normal activity levels in the rat.     

Hypothalamic effector neurons and extended circuitries activated in “neurogenic” stress: A comparison of footshock effects exerted acutely,chronically, and in animals with controlled glucocorticoid levels

Immunolocalization of Fos protein was used to identify and characterize hypothalamic visceromotor populations responsive to acute and chronic intermittent footshock stress, and candidate afferent mediators of hypothalamic effects. Exposure to a single 30 minute footshock session induced maximal Fos expression in the paraventricular hypothalamic nucleus (PVH) 2 hours after the challenge; activated cells corresponded principally to hypophysiotropic neurons expressing corticotropin-releasing factor, with secondary involvement of magnocellular oxytocinergic and autonomic-related projection neurons. Extrahypothalamic cell groups activated in response to acute footshock included ones associated with the processing or modulation of somatosensory/nociceptive inputs, the limbic region of the telencephalon, and visceral sensory mechanisms. Rats with constant corticosterone levels displayed enhanced footshock-induced Fos expression in the parvicellular compartment of the PVH, as well as in certain limbic and somatosensory cell groups, the locus coeruleus, but not in medullary catecholaminergic cell groups. Animals subjected to chronic intermittent stress (2 sessions/day for 7 days) showed only modest evidence of habituation of cellular activation responses in the PVH and most extrahypothalamic regions. Rats bearing retrograde tracer deposits in the PVH and killed 2 hours after acute footshock displayed Fos-positive retrogradely labeled neurons principally in medullary catecholaminergic cell groups, with secondary foci in the hypothalamus, limbic region, and pontine tegmentum. This characterization of footshock-responsive systems identifies cell groups that are in a position to (1) mediate acute stress effects on hypothalamic visceromotor neurons, (2) comprise targets for corticosteroid negative feedback effects, and/or (3) underlie habituation of the neuroendocrine limb of the stress response. J. Comp. Neurol. 393:244–266, 1998. © 1998 Wiley-Liss, Inc.     

Can Cerebrospinal Fluid Pressure Detect Catheter Complications in Patients Who Experience Loss of Effectiveness With Intrathecal Baclofen Therapy?

ObjectiveThe catheter status of patients who presented with loss of intrathecal baclofen (ITB) therapy effectiveness was investigated using measurements of cerebrospinal fluid (CSF) pressure transmitted through the catheter fluid path to the pump. The aim of the study was to estimate the appropriate threshold separating catheter complications from “normal” catheter function, and to compare catheter status based on CSF pressure with the clinical diagnosis.MethodsThis was a prospective, masked nonsignificant risk, research study. Patients (N = 47) received ITB for the treatment of severe spasticity and presented with symptoms of catheter malfunction. CSF pressure data were recorded using an external sensor connected to a needle inserted into the catheter access port. An algorithm calculated the energy of the variations in CSF pressure caused by respiration and heartbeat within the intrathecal space. These data were evaluated against a threshold that separated normal from abnormal catheter function. Catheter status based on the algorithm was compared with the clinical diagnosis.ResultsComplete data were available for 37 patients. Mean CSF pressure energy was significantly higher (p = 0.025; student t-test) for patients diagnosed with normal catheter function vs. catheters with complications. The CSF pressure algorithm matched the clinical diagnosis in 16 of 18 patients with catheter complications (sensitivity = 89%), and 13 of 19 patients with normal catheter function (specificity = 68%).ConclusionIn-clinic CSF pressure data acquisition is technically feasible. Overall, catheter status based on the algorithm demonstrated concordance with the clinical diagnosis in 29 of 37 patients (78.4%).     

Assessment of Patient Preference for Constant Voltage and Constant Current Spinal Cord Stimulation

Objectives: Spinal cord stimulation devices control energy by generating either constant voltage (CV) pulses or constant current (CC) pulses. This study aimed to investigate: 1) whether patients feel differences between CV and CC stimulation; 2) if patients prefer CV or CC stimulation. Methods: Fourteen patients blinded to the type of pulse generation received 20 randomized pairs of 15‐sec pulse trains (CC‐CV, CV‐CC, CV‐CV, or CC‐CC). Patients identified whether the pairs were the same or different, and if they preferred the first or second train. Results: There was no difference in charge‐per‐pulse input between CV and CC modes. Patients performed at chance level in identifying identical pairs (55.7 ± 24.1% correct, 10 trials), and slightly better in identifying different pairs (67.1 ± 25.2% correct, 10 trials). No patients correctly identified all pairs. Patients were categorized based on their performance in this task. Only three patients fell into a category where preference could be established with some confidence with respect to the group averages. Two of these patients preferred CV, while one patient preferred CC. Conclusion: The lack of patient ability to discriminate in this preliminary investigation suggests that patient preference for a stimulation type should not be the key determining factor in choosing a spinal cord stimulation system.     

Metal Carbonyls in the Petroleum Industry

Industrial conditions which utilize temperature, pressure, and carbon monoxide in the presence of metal catalysts are conducive to metal carbonyl formation. An evaluation of the thermodynamic equilibrium data associated with metal carbonyls shows a definite relationship between these parameters which allow us to construct nomographs concerning their equilibrium formation. Metal carbonyls represent a distinct medical hazard. Recommendations for safe exposure limits and safety devices for personnel protection are based on the toxicity associated with metal carbonyls. Analytical methods indicate that adequate monitoring of the carbonyls of nickel, cobalt, and iron can be obtained.     

牙科医生对口腔卫生服务体系的评价

目的 :分析牙科医生的日常工作量和牙医对口腔卫生服务的态度评价 ,有助于口腔卫生服务体系的制定和评价。方法 :根据武汉市卫生部门登记在册的牙科医生 ,采用整群抽样的方法随机选择 2 5 0名牙科医生进行开放式问卷调查。结果 :所调查的 2 5 0名样本中 ,5 2 %为女性 ,牙科医生平均工作年限为 11.6年 ,平均使用 0 .8台牙椅 ,每位牙医平均每天看 15个病人。主要工作时间用于充填治疗和拔牙。 93 %的牙医认为中国口腔卫生服务强调治疗而忽视预防保健。结论 :口腔卫生服务应重视口腔预防保健     

多层螺旋CT对食管鱼刺异物的诊断价值

目的 探讨MSCT对食管鱼刺异物的检出率及临床诊断价值.方法 实验组:取3种鱼的鱼刺各30根,分为大、中、小鱼刺3组,3组鱼刺长度分别为(23.36±0.15)、(28.51±0.07)和(30.89±0.10)mm,直径分别为(4.4.9±0.31)、(1.78±0.09)和(0.49±0.07)mm.将鱼刺按照与食管长轴平行、垂直、斜行方式插入食管模型中,MSCT检查采用轴面扫描结合三维重组技术,观察MSCT和X线平片(CR和DR)对鱼刺的显示情况.临床组:回顾性分析20例经内镜或临床手术证实的食管鱼刺异物患者的资料,所有患者均行MSCT平扫,其中11例行X线平片(CR和DR)检查,15例行食管吞钡棉絮检查,17例行内镜检查,观察几种检查方法对鱼刺的显示情况.对不同方法对鱼刺显示情况的比较采用配对卡方检验.结果 实验组:MSCT检出鱼刺90根(100%),X线平片(CR和DR)检出鱼刺60根(66.7%),MSCT对鱼刺的检出率高于X线平片(CR和DR)(X2=28.03,P<0.01).临床组:20例中,MSCT检出鱼刺20例,且清楚显示鱼刺的位置、大小及其与食管壁和邻近组织的关系;X线平片检出鱼刺2例,食管吞钡棉絮检出鱼刺9例,内镜检出鱼刺14例.MSCT对食管鱼刺异物检出率高于X线平片(cR和DR)检查(X2=7.11,P<0.05)及食管吞钡棉絮检查(X2=4.17,P<01 05),与内镜检查差异无统计学意义(X2=1.33,P>0.05).结论 MSCT轴面扫描结合三维重组技术对食管鱼刺异物及其周围并发症的检出率高,可作为食管鱼刺异物的首选检查方法.