Local cerebral blood flow measured by stable xenon CT during fentanyl-diazepam anesthesia

We assessed the local cerebral blood flow (LCBF) in 40 patients under fentanyl-diazepam anesthesia. The measurement of LCBF was made using 50%–70% stable xenon with 20 min of inhalation interval and a shuttle method for computed tomography imaging. All patients were anesthetized with 5.95±1.76 μg·kg⁻¹ fentanyl and 0.22±0.07 mg·kg⁻¹ diazepam under mechanical ventilation during CBF measurement. The values and distribution of LCBF on non-affected hemisphere appeared to be unaltered by fentanyldiazepam anesthesia. We also assessed the cerebral carbon dioxide reactivity in 6 patients. The cerebral carbon dioxide reactivity, expressed as percentage change in LCBF per unit change in arterial carbon dioxide partial pressure, was 5.39±1.07, and there were no significant differences of reactivity among regions studied. In conclusion, we showed reference values of LCBF and carbon dioxide reactivity, measured by stable xenon-enhanced computed tomography, in patients under fentanyl-diazepam anesthesia. Carbon dioxide reactivity was preserved in all regions including gray matter, white matter, and basal ganglia.     

CLINICAL SIGNIFICANCE OF THE DETECTION OF MINIMAL RESIDUAL DISEASE IN CHILDHOOD B-ALL BY FLOW CYTOMETRY

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甲状腺结节的二维及彩色多普勒超声诊断研究

目的：探讨二维及彩色多普勒超声对甲状腺良、恶性结节的诊断及鉴别诊断价值。方法：120例甲状腺结节经二维超声了解其声像图表现，然后用彩色多普勒检查，观察结节内部及周边血流分布情况，并将其分为4级。结果：120例302个甲状腺结节中，良性结节264个，恶性结节38个。二维超声显示：恶性结节以实性低回声为主，内可见砂粒样钙化，边界不清，无声晕及包膜；良性结节以等、高回声及囊性、囊实性结节为主，形态规则，边界清，多有声晕及包膜。彩色多普勒超声显示：恶性结节的血流显示率明显高于良性结节，收缩期最高血流速度及阻力指数总体上高于良性结节，且以Ⅱ、Ⅲ级血流为主。结论：二维及彩色多普勒超声诊断甲状腺良、恶性结节准确率高。具有较大的临床应用价值。     

拉萨地区高原肺水肿经颅多普勒21例分析

目的:通过经颅多普勒(TCD)检测,了解高原肺水肿(HAPE)患者颅内脑底动脉环上的主要动脉血流动力学及各血流的生理参数,为高原肺水肿的诊断及治疗提供一些参考.方法:将已确诊的HAPE患者,与颞窗通过低频脉冲多普勒(2MHZ),获得颅内脑底动脉环上的主要动脉的多普勒超声频移信号,进行TCD检测.结果:TCD检测后了解到颅内脑底动脉环上的主要动脉:颈内动脉末梢、大脑中动脉、大脑前动脉血流速度(收缩期血流速度,平均血流速度,舒张末期血流速度)与正常人的TCD测值相比明显增快,但舒张末期血流速度(VE )增快较收缩期血流速度(VP )不明显,故频谱仍为低阻波形,搏动指数(PI)、收缩期血流速度与舒张末期血流速度的比值(S/D)正常,阻力指数有所降低.结论:经TCD检测可知高原肺水肿患者在高原(在低氧环境下),颅内主要脑血管扩张,脑血流量增加即颈内动脉系统的MCA,ACA,PICA血流速度(Vs,Vm,Vd)增快,通过TCD检查可为高原医生早期诊断及治疗提供参考.     

Physiological consequences of a high work of breathing during heavy exercise in humans

The healthy respiratory system has a remarkable capacity for meeting the metabolic demands placed upon it during strenuous exercise. For example, in order to regulate alveolar partial pressure of oxygen and carbon dioxide during heavy workloads, a 20-fold increase in alveolar ventilation can occur. The high metabolic costs and subsequent increased work of breathing associated with this ventilatory increase can result in a number of limitations to the healthy respiratory system. Two examples of respiratory system limitations that are associated with a high work of breathing are expiratory flow limitation and exercise-induced diaphragmatic fatigue. Expiratory flow limitation can lead to an inability to increase alveolar ventilation () in the face of increasing metabolic demands, resulting in gas exchange impairment and diminished endurance exercise performance. Furthermore, the high ventilatory requirements of endurance athletes and the inherent anatomical differences in females could make these groups more susceptible to expiratory flow limitation. Fatigue of the diaphragm has also been documented after strenuous exercise and may be related to a mechanism which increases sympathetic vasoconstrictor outflow and reduces limb blood flow during prolonged exercise. This competition between the muscles of respiration and locomotion for a limited cardiac output may have dramatic consequences for exercise performance. This brief review summarizes the literature as it pertains to the work of breathing, expiratory flow limitation, and exercise-induced diaphragmatic fatigue in healthy humans.     

Non-specific bronchial hyper-responsiveness in children with allergic rhinitis: Relationship with the atopic status

An increased prevalence of bronchial hyper-responsiveness (BHR) has been demonstrated in children from a general population, and in non-asthmatic adults with allergic rhinitis. Thus, also children with allergic rhinitis are expected to be at higher risk of BHR. We evaluated the prevalence of BHR in a sample of non-asthmatic children with allergic rhinitis by means of the methacholine (Mch) bronchial challenge, and by monitorizing the airway patency using the daily peak expiratory flow variability (PEFv). Fifty-one children (ranged 6–15 years of age) with allergic rhinitis, ascertained by skin prick test to inhalant allergens, underwent a 14-day peak expiratory flow monitoring, and a Mch bronchial provocation challenge. Thirty healthy children matched for age, and sex served as control group. Thirty-one children in the rhinitis group (61%), and six (20%) in the control group were Mch+ (Mch provocative dose causing a 20% fall of forced expiratory volume in 1 s respect to baseline <2250  μ g, equivalent to 11.50  μ mol). In rhinitic children the PEFv did not significantly differ between Mch+ and Mch− subjects, but the total serum immunoglobulin E (IgE) were higher among Mch+. The persistent form of rhinitis was significantly associated to Mch positivity. Non-asthmatic children with allergic rhinitis displayed a high prevalence of BHR. The BHR was significantly associated with persistent rhinitis and with higher total IgE levels. Nevertheless, the spontaneous changes in airway patency, as expressed by PEFv, were within normal limits both in Mch+ and Mch− children.     

单光子发射计算机断层扫描在颅脑创伤后的临床研究

目的 探索单光子发射计算机断层扫描（SPECF）在脑外伤评估及预后方面的价值的依据。方法 28例中、重度颅脑损伤患者分别于伤后3天、10天及3～4周接受SPECF、CT检查及临床评定。3个月后所有患者行脑外伤综合征的临床测试，对首检SPECF显像阳性者复查SPECF，分析首检SPECF显像阳性者与损伤程度的关系，动态观察SPECF显像与预后的关系。结果 SPECF显像阳性与脑损伤程度有关，首检SPECF显像阳性提示预后良好，复查SPECF显像阳性提示多出现脑外伤综合征。对幕上损伤患者表现的小脑症状、体征可以做出合理的解释。结论 在中至重度颅脑损伤后SPECF显像与CT扫描比较更敏感，脑SPECF具有无创性、功能性及灵敏性高等特点，是脑外伤后功能评估、预后判断及临床研究的可靠方法。     

Brain perfusion territory imaging applying oblique-plane arterial spin labeling with a standard send/receive head coil.

A new method for the selective spin labeling of left- or right-sided supplying arteries of the brain without the need for additional RF coils is demonstrated. A clinical 1.5 T scanner was used. The spatial selectivity of the labeling process is based on the limited coverage of the excitation field of a standard send/receive head coil together with an oblique positioning of the labeling plane. A computer simulation was used to optimize key labeling parameters under the condition of laminar flow. The validity of the computer model results was confirmed by MRI measurements with a flow model. For human studies, a double-inversion continuous arterial spin labeling (CASL) sequence was modified to allow for arbitrary positioning of the labeling plane. The obtained perfusion-weighted images showed a clear delineation of the perfusion territories of the selected arteries in the anterior circulation of the brain and good gray/white matter contrast.     

Flow cytometric analysis of localized adenocarcinoma of the prostate: the use of archival DNA analysis in conjunction with pathological grading to predict clinical outcome following radical retropubic prostatectomy

Fifty-four specimens from patients undergoing radical prostatectomy for clinically confined prostate cancer between 1983 and 1987 were reviewed to determine the potential for flow cytometric (FCM) analysis of DNA ploidy and replication rate to predict disease recurrence. Each specimen was deparaffinized for FCM analysis and the pathology slides were reviewed by a single pathologist. FCM characteristics were correlated with pathological grade and stage, and both were correlated with disease status. In this series of patients, routine FCM analysis of DNA ploidy and replication rate failed to significantly enhance the ability of standard histopathological grading to predict disease recurrence in patients having clinically localized prostate cancer. Aneuploid tumors pathologically confined to the prostate did not appear to negatively affect prognosis.     

Effects of chronic treatment with a nitric oxide donor on nerve conduction abnormalities and endoneurial blood flow in streptozotocin-diabetic rats

Abstract. This study examined the ability of nitrova-sodilator treatment with isosorbide dinitrate to prevent the development of reduced nerve conduction velocity and nutritive blood flow in streptozotocin-induced diabetes mellitus in rats. Two month untreated diabetes caused approximately 23% and 13% reductions in sciatic motor and saphenous nerve sensory conduction velocity ( P < 0.001). Isosorbide dinitrate treatment provided 64.6 and 67.6% protection for motor and sensory nerves, respectively ( P < 0.01). Sciatic endoneurial nutritive blood flow was measured by microelectrode polarography and a hydrogen clearance technique. After 1 month untreated diabetes, flow was reduced by 41.9% ( P < 0.001). Isosorbide dinitrate treatment for 1 month in non-diabetic and diabetic rats significantly increased blood flow ( P < 0.01). When between-group variations in blood pressure were taken into account, vascular conductance increased by 29% and 31% in non-diabetic and diabetic rats, respectively ( P < 0.01). Thus, nitrovasodilator treatment improves nerve perfusion and function in experimental diabetes, probably by compensating for reduced endothelium-derived nitric oxide release or action.