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61.
BACKGROUND: Stress can exacerbate a number of psychiatric disorders, many of which are associated with prefrontal cortical (PFC) cognitive deficits. Biochemical studies demonstrate that mild stress preferentially increases dopamine turnover in the PFC. Our study examined the effects of acute, mild stress exposure on higher cognitive function in monkeys and the role of dopaminergic mechanisms in the stress response. METHODS: The effects of loud (105-dB) noise stress were examined on a spatial working memory task (delayed response) dependent on the PFC, and on a reference memory task with similar motor and motivational demands (visual pattern discrimination) dependent on the inferior temporal cortex. The role of dopamine mechanisms was tested by challenging the stress response with agents that decrease dopamine receptor stimulation. RESULTS: Exposure to noise stress significantly impaired delayed-response performance. Stress did not impair performance on "0-second" delay control trials and did not alter visual pattern discrimination performance, which is consistent with impaired PFC cognitive function rather than nonspecific changes in performance. Stress-induced deficits in delayed-response performance were ameliorated by pretreatment with drugs that block dopamine receptors (haloperidol, SCH 23390) or reduce stress-induced PFC dopamine turnover in rodents (clonidine, naloxone hydrochloride). CONCLUSIONS: These results indicate that stress impairs PFC cognitive function through a hyperdopaminergic mechanism. Stress may take the PFC "off-line" to allow more habitual responses mediated by posterior cortical and subcortical structures to regulate behavior. This mechanism may have survival value, but may often be maladaptive in human society, contributing to the vulnerability of the PFC in many neuropsychiatric disorders.  相似文献   
62.
Determination of Functional Residual Capacity (FRC) can be performed through washout methods, indicator gas dilution or bodyplethysmography. Some of these techniques have been adapted for use in intensive care patients whilst being mechanically ventilated. However, most measurement setups are bulky, cumbersome to use and their running costs are high. Hence FRC measurement has not become a routine method in intensive care although it offers considerable advantages in the management of ventilated patients such as the determination of "best PEEP", the detection of progressive alveolar collapse in the course of acute lung injury and during weaning from mechanical ventilation. Up to now most efforts to improve and simplify FRC measurement were made at the expense of accuracy. An ideal method ought to be accurate, easy to handle and cost-effective. It should supply not only FRC data but also information about intrapulmonary gas distribution and dead space. These demands can be met using modern data acquisition software. The pros and cons of all methods available for FRC measurement are discussed in view of their suitability for intensive care patients. A conventional nitrogen washout using emission spectroscopy for measurement of nitrogen concentration gives satisfying exact values for the determination of the parameters mentioned above. The measurement error can be lowered under 5% by special corrections for flow and nitrogen signal (delay and rise times, changes of gas viscosity). For flow measurement a normal pneumotachograph can be used. Using a laptop computer for data acquisition the bed-side monitor fulfills most of the demands in intensive care. It is then also possible to measure indices of intrapulmonary gas distribution such as Alveolar Mixing Efficiency and Lung Clearance Index.  相似文献   
63.
Fibromuscular dysplasia (FMD) is one of the most important mimics of vasculitis. FMD is more prevalent in women and may cause infarcts of organ systems including the brain, intestines, and extremities. These acute clinical presentations often raise the suspicion of vasculitis and therefore rheumatologists will be asked to evaluate these patients. One of the frequent manifestations of FMD is renal artery involvement. Angiographic evaluation often shows a "string of beads" appearance of the renal arteries but sometimes only tapering of the vascular lumen or cutoffs may be seen. In contrast, hepatic artery involvement with FMD occurs much less frequently and may initially present with life threatening intraabdominal bleeding. Celiac angiograms of these patients often show aneurysms, a presentation similar to vasculitis. Only a high level of suspicion for FMD and careful evaluation of clinical facts will lead to correct diagnosis. This will prevent the wrong diagnosis of vasculitis and subsequent treatment with potentially toxic medications. We present 2 cases of FMD involving the renal and hepatic arteries that illustrate this diagnostic challenge.  相似文献   
64.
A quarter of a century ago, in October 1964, the first spinal cord injury center in Switzerland was opened at Geneva University Hospital. At that time all para- and tetraplegics were classified as "high-risk" patients. Early mortality, covering the initial four weeks following trauma, was still around 15%. The available resources for diagnostic assessment were limited to clinical examination and neuroradiological assessment (subsequently improved by the introduction of tomography and gas myelography). A great many patients suffered a deteriorated neurological level due to inadequate, multiple transfers between hospitals. Most patients who are paralyzed following a road-traffic accident show severe polytrauma. Their chances of survival and functional recovery have greatly improved in recent years due to efficient emergency transport by helicopter, admission to an intensive care unit (respiratory therapy, prophylactic anticoagulation, gastrointestinal cytoprotection, prevention of pressure sores, etc.) and a comprehensive medico-surgical team approach (orthopedic surgeons, neurosurgeons, ICU specialists, internists, etc.). Evaluation of the spine and spinal cord by NMR and CT scan allows precise assessment of the extent of CNS damage and provides additional guide-lines regarding efficient surgical reposition and spinal fusion. Ongoing experimental research in neurophysiology and neurobiochemistry of the brain and spinal cord is presently yielding some interesting results which hold out new hopes for functional recovery in some specific types of incomplete spinal cord trauma.  相似文献   
65.
Double contrast examination constitutes an important element in radiological gastric examination. The author examines the history of the term "double contrast" and defines the designation of "double contrast examination". The exclusive use of the double contrast method reduces the diagnostic value of gastric X-ray examinations. Thus a method is suggested that will avoid the disadvantages of exclusive double contrast examination while adequately including double contrast in the gastric examination. This is done by using various methods - according to the problem posed - in order to achieve the double contrast.  相似文献   
66.
67.
A multicentric open clinical trial was carried out by 8 practising specialists in dermatology or paediatrics in patients with bacterial skin diseases who were subjected to a systemic therapy with Syncillin (=Azidocillin). The Syncillin presentation for adults and schoolchildren was tablets of 750 mg each, and sachets of 125 mg or 250 mg for infants. The duration of treatment was 10 days. The parameters analyzed were bacteriological findings and the clinical course of disease. 71 (=74%) of the 96 patients included in this study were considered as cured, 21 (=22%) as improved and 4 patients (=4%) as unchanged. Bacterial identification was still positive in 10 cases after the termination of treatment. However, this did not preclude the assessments of "cured' (3 cases) or "improved' (7 cases). The tolerance of the preparation was considered as "very good' or "good' in 91 and as "poor' in 5 patients. The most common side effects were nausea and diarrhoea. Exanthema was observed in 2 cases. None of these side effects, however, made a discontinuation of medication necessary. The era of rational and well-directed chemotherapy enables good therapeutic approach also to bacterial skin diseases.  相似文献   
68.
69.
PURPOSE: Patients with active pars planitis have increased levels of a 36 kDa protein (p-36) in their circulation. The current studies were undertaken to determine the primary structure of this protein. METHODS: A degenerate oligonucleotide probe based on the amino terminal sequence of p-36 was used to identify a clone from a human spleen cDNA library. The cDNA insert was subcloned into the EcoR1 site of pUC-19, and both strands were sequenced. Southern blot analysis was used to study the genomic hybridization pattern. p-36 cDNA was subcloned in a pSG5 expression vector, and the construct was used to transfect COS-7 cells. RESULTS: The cDNA sequence contained an open reading frame of 966 base pairs encoding a protein of 322 amino acids, an untranslated region of 322 base pairs, and 2693 base pairs at the 5' and 3' ends, respectively. The deduced amino acid sequence showed 96.8% identity with the carboxy-terminal region of a yeast nucleopore complex protein, nup 100. Southern blot analysis of human genomic DNA revealed a simple hybridization pattern. Transfection of p-36 cDNA in COS-7 cells resulted in the presence of p-36 mRNA and expression of protein. CONCLUSIONS: The 36 kDa protein (p-36) detected at increased levels in the blood of patients with active pars planitis was cloned from a human spleen cDNA library. Its deduced amino acid sequence is homologous with the carboxy-terminal region of a nucleopore complex protein. Thus, we refer to this protein as nup36.  相似文献   
70.
Loading induced fluid flow has recently been proposed as an important biophysical signal in bone mechanotransduction. Fluid flow resulting from activities which load the skeleton such as standing, locomotion, or postural muscle activity are predicted to be dynamic in nature and include a relatively small static component. However, in vitro fluid flow experiments with bone cells to date have been conducted using steady or pulsing flow profiles only. In this study we exposed osteoblast-like hFOB 1.19 cells (immortalized human fetal osteoblasts) to precisely controlled dynamic fluid flow profiles of saline supplemented with 2% fetal bovine serum while monitoring intracellular calcium concentration with the fluorescent dye fura-2. Applied flows included steady flow resulting in a wall shear stress of 2 N m(-2), oscillating flow (+/-2 Nm(-2)), and pulsing flow (0 to 2 N m(-2)). The dynamic flows were applied with sinusoidal profiles of 0.5, 1.0, and 2.0 Hz. We found that oscillating flow was a much less potent stimulator of bone cells than either steady or pulsing flow. Furthermore, a decrease in responsiveness with increasing frequency was observed for the dynamic flows. In both cases a reduction in responsiveness coincides with a reduction in the net fluid transport of the flow profile. Thus. these findings support the hypothesis that the response of bone cells to fluid flow is dependent on chemotransport effects.  相似文献   
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