正常眼压性青光眼的HRF评价

目的　研究正常眼压性青光眼 (normaltensionglaucoma ,NTG )患者眼底血流特点及影响因素。方法　应用海德堡共焦扫描激光多普勒视网膜血流分析仪 (heidelbergretinaflowmeter ,HRF)检测了NTG患者 ( 18例 3 6眼 )的视盘筛板及视盘旁颞侧、鼻侧视网膜血流参数。Octopus 10 1视野计检测 3 0°中心视野。空腹静脉血检测患者血液流变学参数。结果　与正常人眼底血流参数比较 ,NTG患者筛板及颞侧视盘旁视网膜血流量、血流速、红细胞移动速率 ,鼻侧视盘旁视网膜血流量均明显低于正常组 (P <0 0 1) ;NTG患者颞侧视盘旁视网膜血流速、红细胞移动速率较鼻侧明显降低(P <0 0 1)。NTG患者筛板血流量与眼压呈正相关 (P <0 0 1) ;颞侧视盘旁视网膜血流量与眼压及屈光度呈正相关 (P <0 0 5 ) ;筛板血流速、红细胞移动速率与屈光度呈正相关 (P <0 0 5 )。鼻侧视盘旁视网膜血流量、颞侧及鼻侧视盘旁视网膜血流速、红细胞移动速率与屈光度呈正相关 (P <0 0 1)。结论　NTG患者眼底血流量较正常人低 ,支持微循环障碍 (血管学说 )在NTG的发病机制中扮演重要角色。屈光度是影响NTG患者眼底血流的危险因素。     

硝普钠在高血压脑出血术中的降压及脑保护作用

目的探讨硝普钠在高血压脑出血围术期的降压及脑保护作用。方法选择高血压脑出血患者56例,分为硝普钠组(36例)和对照组(即硝酸甘油组,20例)。对两组患者围术期的平均动脉压、心率、颈内静脉血氧饱和度及术后病死率进行对比观察。结果硝普钠组患者用药后的平均动脉压、心率、颈内静脉血氧饱和度均比术前明显改善,而硝酸甘油组则改变不明显;硝普钠组患者术后病死率比硝酸甘油组明显下降。结论硝普钠具有降低外周血管阻力、减轻心脏前负荷、降低左室充盈压及改善心功能的作用,且不降低心输出量,从而纠正全身各重要脏器的缺血、缺氧状况,并且静脉滴注给药可使降压幅度平稳且复压迅速;术中连续应用硝普钠对神经胶质细胞具有延迟保护作用,因此,硝普钠对高血压脑出血患者具有较好的降压及脑保护作用,并能降低该类患者术后的病死率。     

Nitroglycerin rebound associated with vascular, rather than platelet, hypersensitivity

OBJECTIVES

The purpose of this study was to determine whether acute withdrawal of nitroglycerin (NTG) during hemodynamic tolerance is associated with platelet hypersensitivity.

BACKGROUND

Nitroglycerin is an effective antianginal medication but its use is limited by the development of tolerance and rebound. We have previously demonstrated a sustained inhibition of platelet function during continued use of NTG, but whether cessation of NTG is associated with an increase in platelet function that may contribute to rebound is unknown.

METHODS

Normal porcine aortic media were exposed to flowing arterial blood from pigs (n = 8) treated continuously with NTG patches (Nitrodur 0.8 mg/h) for 48 h. Platelet function, blood pressure and the responses to angiotensin II infusion were evaluated before, during and after NTG treatment.

RESULTS

Mean arterial pressure fell by 15% after 3 h of treatment compared with control, returned to baseline by 48 h and increased significantly 2 h after drug removal. Autologous ⁵¹Cr-labelled platelet deposition on the aortic media was reduced by 30% after 48 h of continuous NTG administration compared with baseline (p = 0.02) and remained decreased 2 h after cessation of NTG therapy. Platelet aggregation to thrombin decreased in parallel to the decrease in platelet deposition. Blood pressure increase after intravenous injection of 10 μg of angiotensin II was blunted during treatment with NTG but increased significantly 2 h after cessation of nitrate therapy when compared with baseline.

CONCLUSIONS

Supersensitivity of the vessel wall to vasoconstrictors such as angiotensin 11, but not platelet hyperactivity, may contribute to the rebound phenomenon after acute nitrate withdrawal.     

Atorvastatin attenuates NF-κB activation in trigeminal nucleus caudalis in a rat model of migraine

Nitroglycerin-induced NF-κB activation in trigeminal nucleus caudalis is believed to be partly involved in the pathogenesis of migraine. Atorvastatin, an inhibitor of HMG-CoA reductase, is thought to have pleiotropic effects in various neurologic diseases. Moreover, there are several lines of evidences that atorvastatin inhibits NF-κB activation in peripheral blood mononuclear cells. Thus, this study aims to explore whether atorvastatin attenuates NF-κB activation in trigeminal nucleus caudalis in a nitroglycerin-induced migraine model. A significant increase in nuclear content of p65, an indicator of NF-κB activation, was detected in trigeminal nucleus caudalis in rats following injection with nitroglycerin. However, the nitroglycerin-induced NF-κB activation in trigeminal nucleus caudalis was attenuated by pretreatment with atorvastatin in a dose-dependent fashion. These results suggest that atorvastatin may be a novel and promising candidate for future treatment or prophylaxis of migraine via attenuating activation of NF-κB in trigeminal nucleus caudalis.     

Comparison of retinal nerve fiber layer measurements between NTG and HTG using GDx-vCC

PURPOSE: To compare quantitative polarimetric measurements in eyes with NTG and HTG using GDx-VCC. Both groups were matched by age and glaucoma stage based on the Humphrey visual field test. METHODS: We retrospectively reviewed the records of 146 patients who underwent Humphrey field analysis (HFA) and GDx-VCC. We compared outcomes of retinal nerve fiber layer (RNFL) parameters among the three groups by ANOVA and between each pair of groups using the Tukey-Kramer Post-Hoc test. We also evaluated the sensitivity and specificity of GDx-VCC in detecting glaucoma in each group. RESULTS: The mean age and HFA mean deviation (MD) were 55.6 +/- 9.5 years and -0.8 +/- 1.5 dB in 47 control patients, 59.4 +/- 9.0 years and -5.77 +/- 4.38 dB in 49 NTG patients, and 59.4 +/- 11.7 years and -8.09 +/- 6.77 dB in 51 HTG patients, respectively. All thickness parameters were lower in HTG patients compared to NTG patients, but there were no significant differences in ratio parameters between age-matched early HTG and NTG patients. The sensitivity of GDx-VCC was significantly higher in both early and total HTG patients compared to the respective groups of NTG patients. CONCLUSIONS: Compared to eyes with NTG, eyes with HTG showed reduced RNFL thickness and ratio parameters when patients were age and visual field matched. GDx-VCC appeared to be more sensitive in detecting RNFL damage in HTG patients.     

Fistulography of a Patent Hemodialysis Access: When Not to Treat and Implications for Establishing a Nontreatment Rate

Purpose

To establish a rate of nonintervention in patients referred for hemodialysis access fistulography and to report clinical and fistulographic variables associated with nonintervention.