Molecular and electrophysiological evidence for a GABAc receptor in thyrotropin-secreting cells

In the pituitary, GABA regulates the release of several hormones via different receptors. GABA(C) receptors are heterooligomers that differ from GABA(A) receptors in that they contain p-subunits and are insensitive to bicuculline. However, molecular and functional evidence for the presence of GABA(C) receptors outside the retina has yet to be established. The present work was performed on guinea pig and rat pituitaries. Both Northern blot and RT-PCR analysis showed that, although rho1- and rho2-subunits were expressed at similar levels in the rat retina, rho1 messenger RNA (mRNA) was enriched, relative to rho2 mRNA in the rat pituitary. Northern blot experiments also showed that, in the pituitary, rho1 and rho2 mRNAs are shorter in size than those expressed in the retina. The use of a subunit-specific antibody revealed colocalization of rho1-subunit and anti-TSH labeling on rat pituitary sections. TSH guinea pig pituitary cells were also labeled with a rho-subunit antiserum. Moreover, whole-cell patch clamp on single guinea pig TSH cells showed that GABA induced a bicuculline-insensitive Cl- current. In contrast to the Cl- current generated by GABA(C) receptors in the retina, the bicuculline-insensitive Cl- currents in TSH cells quickly desensitized. These results suggest that a novel GABA(C) receptor may regulate TSH secretion and that the structure and/or biochemical regulation of this pituitary receptor is different from that found in the retina.     

不明原因晕厥患者电生理检查结果分析

目的 探讨电生理检查对不明原因晕厥患者的诊断价值。方法 对268例经无创性检查未能确定病因的晕厥患者进行电生理检查，并对电生理结果及其并发症进行统计分析。结果 电生理检查总的阳性率为38％，随年龄的增加，其电生理检查的阳性率亦增加，其中70岁以上患者因患冠心病者比例较高其电生理检查阳性率高达50％，但该组并发症并无增加。结论 电生理检查对不明原因晕厥患者，尤其是老年伴器质性心脏病患者有一定诊断价值。     

Where practice makes perfect in texture discrimination: evidence for primary visual cortex plasticity.

In terms of functional anatomy, where does learning occur when, for a basic visual discrimination task, performance improves with practice (perceptual learning)? We report remarkable long-term learning in a simple texture discrimination task where learning is specific for retinal input. This learning is (i) local (in a retinotopic sense), (ii) orientation specific but asymmetric (it is specific for background but not for target-element orientation), and (iii) strongly monocular (there is little interocular transfer of learning). Our results suggest that learning involves experience-dependent changes at a level of the visual system where monocularity and the retinotopic organization of the visual input are still retained and where different orientations are processed separately. These results can be interpreted in terms of local plasticity induced by retinal input in early visual processing in human adults, presumably at the level of orientation-gradient sensitive cells in primary visual cortex.     

Clinical and electrophysiological indications for surgical treatment in patients with Wolff-Parkinson-White syndrome]

20 patients with WPW syndrome and recurrent tachyarrhythmias were studied clinically and electrophysiologically. The localization and electrophysiological properties of accessory pathways and other heart structures were estimated before the surgical treatment. 13 patients (pts) suffered syncope in the course of atrial flutter or atrial fibrillation with heart rate greater than 300/min, often proceeding into ventricular fibrillation or atrioventricular tachycardia greater than 260/min, which sometimes proceeds into atrial/ventricular fibrillation. 6 pts experienced dizziness or fainted during tachyarrhythmias or rhythm changes. In 15 pts antiarrhythmic drugs in monotherapy or various combinations did not prevent recurrence of tachyarrhythmias. In 4 of 5 other pts only amiodarone was effective but the drug was discontinued due to serious adverse effects. The lack of good effect of antiarrhythmic drug therapy can be based on mutually unfavorable electrophysiologic properties of the accessory pathways and other heart structures. Pts who experienced syncope had a particularly short effective refractory period (ERP) of the accessory pathways in ante- and retro-grade direction and short ERP of the ventricle muscle. Additionally, there were multiple accessory pathways, heart muscle impairement and frequent ventricular premature beats--factors triggering the tachyarrhythmias.     

室上性心动过速中旁道折返的少见现象

报告阵发性室上性心动过速（PSVT）电生理检查中发现的几种少见的旁道电生理特性。例1为一左侧隐匿性房室旁道参与的房室折返性心动过速,其心室扫描示旁道逆向有效不应期260ms,但520－390ms时无逆向传导功能。例2为一慢－慢型房室交接区折返性心动过速,同时存在一条右侧隐匿性房室旁道作为旁观者。例3为一宽QRS波群心动过速,其体表心电图呈典型马海姆纤维型预激综合征,电生理揭示存在左侧房室隐匿性旁道和束室旁道两条附加旁道,前者为心动过速的逆传支,后者与房室结－希室束同为顺传支。对上述几种少见的电生理现象临床意义进行讨论。     

The autonomic dysfunction in patients with ankylosing spondylitis: a clinical and electrophysiological study

The aim of this study was to determine autonomic nervous system (ANS) functions by using clinical and electrophysiological tests in patients with ankylosing spondylitis (AS). Twenty AS and 20 healthy control subjects were recruited. Demographic data, symptoms related with ANS, and neurological findings were recorded. Clinical measurements including the heart rate variation with deep breathing (HRV), heart rate response to standing (HRS), systolic blood pressure response to standing, and diastolic blood pressure response to isometric exercise were obtained to assess parasympathetic and sympathetic functions of the subjects. The electrophysiological assessments of ANS were performed by sympathetic skin response (SSR) and R-R interval variation (RRIV) measurements for the sympathetic and parasympathetic functions, respectively. Patients with AS were subdivided into two groups depending on the activity of disease. The difference between the groups and relationship between ANS variables and clinical entities were determined. Fifteen male and five female AS patients with a mean age of 38 +/- 8.05 years and 14 male and six female healthy control subjects with a mean age of 40 +/- 9.8 years were included in the study. All the subjects were totally symptom free for ANS involvement and had normal neurological examination findings. The levels of HRV, HRS, and the mean RRIV values were significantly lower in AS patients than in control subjects. The clinical ANS parameters of the patients having more active disease were lower than in subjects with mild disease in regard to HRV values and SSR amplitudes and higher in regard to SSR latencies. The HRV values were found to be correlated with the mean scores of Bath ankylosing spondylitis disease activity index (BASDAI) and C-reactive protein (CRP) levels, and the mean latencies of SSR were correlated with BASDAI scores and CRP levels. In conclusion, our study indicates a subclinical mainly parasympathetic dysfunction of ANS in patients with AS which can be related with disease activity.     

Intravenous and oral encainide: electrophysiological effects in patients with paroxysmal reciprocating supraventricular tachycardia

The electrophysiologic effects of encainide (E) after acute i.v. (1 mg/kg in 60') and oral administration (75 to 150 mg/die for 48-72 h) were evaluated in 10 pts with PSVT (5 men and 5 women, mean age 48 +/- 15 years). The mechanism of PSVT was related to a reentry through an accessory A-V pathway in 6 cases while in the other 4 the reentry was confined in the A-V node. PA, AH and HV intervals lengthened from 42.8 +/- 5.1, 77.8 +/- 19.7 and 38.3 +/- 6.6 msec to 50 +/- 13.5, 91.7 +/- 22.9 and 49.4 +/- 12.9 and to 48.3 +/- 7.1, 94.4 +/- 33.9 and 44.4 +/- 9.2 msec, after i.v. and oral E respectively. Atrial and ventricular refractory periods showed slight not significant variations. Wenckebach point lengthened from 316 +/- 28 msec to 354 +/- 32 and to 359 +/- 45 msec, after i.v. and oral E respectively. Tachycardia cycle length was 358 +/- 32 msec in basal conditions. After i.v. E tachycardia was inducible only in 6 cases, with a mean cycle length of 403 +/- 48 msec. After oral E tachycardia was reproduced only in 3 patients with a mean cycle length of 433 +/- 85 msec. Nine patients were treated chronically with E, at a mean dose of 89 +/- 36 mg/day. After a follow-up of 18 +/- 8 months, tachycardia recurred but with a marked reduction of the attacks, in 3 patients; only 3 patients complained of side effects (blurred vision). Thus E is highly effective in the prevention of PSVT; the drug seems well tolerated thanks to the low dosage required for the control of PSVT.     

268名不明原因晕厥患者电生理检查结果分析

晕厥是临床常见症状之一 ,其病因多种多样。尽管动态心电图监测和倾斜试验对部分心源性和神经血管性晕厥患者可作出诊断 ,但仍有近一半的晕厥原因通过无创性的检查难以确诊 ,需要进行有创性电生理检查。本文对 2 68名原因不明晕厥患者的电生理检查结果进行了回顾性分析。病例选择与电生理检查方法　所选病例为 1 990年至2 0 0 0年在德国海德堡大学医院因晕厥原因不明接受过电生理检查的患者。这些患者均有过 3次以上的晕厥发作 ,且通过无创性检查包括病史、体格检查、心电图、动态心电图、超声心动图、颈动脉窦试验、倾斜试验等未能明确晕厥…     

Neurophysiologic evidence for a central sensitization in patients with fibromyalgia

OBJECTIVE: To determine whether abnormalities of peripheral and central nociceptive sensory input processing exist outside areas of spontaneous pain in patients with fibromyalgia (FM) as compared with controls, by using quantitative sensory testing (QST) and a neurophysiologic paradigm independent from subjective reports. METHODS: A total of 164 outpatients with FM who were attending a self-management program were invited to participate in the study. Data for 85 patients were available and were compared with those for 40 non-FM controls matched for age and sex. QST was performed using thermal, mechanical, and electrical stimuli at locations of nonspontaneous pain. Pain assessment was 2-fold and included use of subjective scales and the spinal nociceptive flexion reflex (NFR), a specific physiologic correlate for the objective evaluation of central nociceptive pathways. Questionnaires regarding quality of life and the impact of FM were available. RESULTS: Participants were mainly middle-aged women, with a mean disease duration of 8 years. Between-group differences were significant for neurophysiologic, clinical, and quality of life measures. In patients with FM, peripheral QST showed significantly altered cold and heat pain thresholds, and tolerance to cold pain was radically reduced. The median NFR threshold in patients with FM (22.7 mA [range 17.5-31.7]) was significantly decreased compared with that in controls (33 mA [range 28.1-41]). A cutoff value of <27.6 mA for NFR provided sensitivity of 73% and specificity of 80% for detecting central allodynia in the setting of FM. CONCLUSION: Our results strongly, although indirectly, point to a state of central hyperexcitability of the nociceptive system in patients with FM. The NFR can be used to assess central allodynia in FM. It may also help discriminate patients who may benefit from use of centrally acting analgesics.     

Preliminary evidence for cachexia in patients with well-established ankylosing spondylitis

OBJECTIVES: Cachexia, defined as an accelerated loss of skeletal muscle in the context of a chronic inflammatory response, is common in rheumatoid arthritis but it has not been demonstrated in patients with ankylosing spondylitis (AS). The aim of this study was to determine muscle wasting and its functional consequences in a group of patients with well-established AS. METHODS: Nineteen male patients (mean age 53 yrs) with long-standing AS (mean disease duration 19 yrs) and radiological changes (84% had one or more syndesmophytes) were compared with 19 age-matched healthy males with similar levels of habitual physical activity. Body composition was assessed by dual energy X-ray absorptiometry. Muscle strength was measured by isokinetic knee extension and hand grip dynamometry, and by 30 s arm curl and chair sit-to-stand tests. RESULTS: AS patients showed a statistically and clinically significant 12% reduction in arms and legs lean mass, a proxy measure of total body skeletal muscle mass, compared with healthy controls (P < 0.05). This muscle loss was significantly associated with reduced upper and lower body strength (correlation coefficients ranging between 0.37 and 0.79, P < 0.05). CONCLUSION: These results provide preliminary evidence that cachexia is a functionally relevant systemic complication of AS, particularly in patients with long-standing disease and radiological changes. Progressive resistance training and other interventions aimed at stimulating skeletal muscle growth might be beneficial in this population, and further studies on the pathophysiology of cachexia in AS patients are needed.     

Serial echocardiograms in patients with congestive cardiomyopathies: lack of evidence for thrombus formation

We studied 90 patients with congestive myocardial disease documented at cardiac catheterization (46 idiopathic, 39 ischemic, and 5 hypertensive) who underwent M-mode and two-dimensional echocardiograms every 2-3 months for up to 7 years (mean 3.4 +/- 1.6 years, +/- 1 S.D.). All had angiographic evidence of severe left ventricular dysfunction (left ventricular ejection fraction less than 40%), and were on a variety of inotropic, diuretic, and vasodilating drugs. Only 9 were ingesting anticoagulants (5 warfarin and 4 aspirin), those on warfarin had documented pulmonary emboli or deep venous thrombosis. All but 4 patients were in normal sinus rhythm. Only one subject in this group was found to have a myocardial (left ventricular) thrombus. Postmortem examinations of 27 patients confirmed the ultrasound data. Thus, we conclude that cardiac thrombi are unusual in patients with congestive cardiomyopathies and rarely develop over the course of the illness even in the absence of chronic anticoagulation.     

Brugada综合征的电生理检查和置入性心脏复律除颤器治疗

目的　探讨Brugada综合征的电生理检查和置入性心脏复律除颤器 (ICD)治疗临床研究。方法　心电图自发性或普罗帕酮药物试验表现为Brugada波的 10例患者行电生理检查 ,均为男性 ,平均年龄 (41± 10 )岁 ,经超声心动图和冠状动脉造影检查未发现器质性心脏病。电生理检查诱发心室颤动 (室颤 )并对有条件者置入ICD治疗。结果　 3例有家族性心脏猝死史 ,4例有反复晕厥史 ,其中 2例晕厥发作时心电图记录到室颤。电生理检查 ,AH和HV间期分别为 5 0～ 12 4 (86± 2 1)ms和 4 1～ 84 (5 8± 15 )ms ,4例晕厥者诱发室颤 ,1例心悸者诱发房室折返性心动过速 ,3例有自发性或诱发心房颤动。 4例诱发室颤者中 ,3例置入ICD ;另 1例因经济原因未置入ICD ,随访中发生猝死。1例诱发房室折返性心动过速者作左侧房室旁路射频导管消融治疗。结论　有晕厥症状的Brugada综合征患者 ,经电生理检查 ,室颤有很高的诱发率 ,是猝死的高危人群 ,为了防止猝死应置入ICD治疗。     

Implantable loop recorders detect tachyarrhythmias in symptomatic patients with negative electrophysiological studies

BACKGROUND: Moderate red wine consumption improved endothelial function in normal volunteers. Herein we explored the effects of moderate red wine consumption in endothelial function and in oxidative stress in patients with an acute coronary syndrome. METHODS: 20 patients treated with percutaneous coronary interventions after an acute coronary syndrome were randomized to a red-wine group (n=9, 250 ml daily, Cabernet Sauvignon) or to a control group (n=11, abstinence from alcoholic beverages). Studies were performed at baseline and after 2 months. Endothelial function was estimated by flow-mediated vasodilatation of the brachial artery. Plasma antioxidant capacity was measured by total antioxidant reactivity and ferric reducing antioxidant power. Oxidative damage was evaluated by measurements of 8-OH deoxyguanosine content in leukocyte deoxyribonucleic acid. RESULTS: The endothelium dependent/independent dilatation ratio significantly improved compared to baseline in both groups. The 8-OH deoxyguanosine content decreased significantly in both groups; this effect was more pronounced with wine (p<0.002 vs. control). Oxidative deoxyribonucleic acid damage in controls decreased from 13.1+/-1.1 to 10.0+/-1.0 (p<0.003); with wine from 13+/-0.8 to 5.6+/-0.7 per 10(5) guanosines (p<0.001; p<0.002 vs. control). Total antioxidant reactivity increased from 240+/-18 to 268+/-18 microM in the control group and from 273+/-20 to 330+/-15 microM in the wine group (p<0.03 vs. control). Ferric reducing antioxidant power increased from 1106+/-60 to 1235+/-42 microM in the control group and from 1219+/-82 to 1450+/-63 microM in the wine group (p<0.001 vs. control). CONCLUSIONS: The addition of moderate amounts of red wine did not improve endothelial function beyond conventional therapy, whereas it showed benefits in parameters of oxidative stress in these patients.