The hemodynamic response of the alpha rhythm: an EEG/fMRI study

EEG was recorded during fMRI scanning of 16 normal controls in resting condition with eyes closed. Time variations of the occipital alpha band amplitudes were correlated to the fMRI signal variations to obtain insight into the hemodynamic correlates of the EEG alpha activity. Contrary to earlier studies, no a priori assumptions were made on the expected shape of the alpha band response function (ARF). The ARF of different brain regions and subjects were explored and compared. It was found that: (1) the ARF of the thalamus is mainly positive. (2) The ARFs at the occipital and left and right parietal points are similar in amplitude and timing. (3) The peak time of the thalamus is a few seconds earlier than that of occipital and parietal cortex. (4) No systematic BOLD activity was found preceding the alpha band activity, although in the two subjects with the strongest alpha band power such correlation was present. (5) There is a strong and immediate positive correlation at the eyeball, and a strong negative correlation at the back of the eye. Furthermore, it was found that in one subject the cortical ARF was positive, contrary to the other subjects. Finally, a cluster analysis of the observed ARF, in combination with a Modulated Sine Model (MSM) fit to the estimated ARF, revealed that within the cortex the ARF peak time shows a spatial pattern that may be interpreted as a traveling wave. The spatial pattern of alpha band response function represents the combined effect of local differences in electrical alpha band activity and local differences in the hemodynamic response function (HRF) onto these electrical activities. To disentangle the contributions of both factors, more advanced integration of EEG inverse modeling and hemodynamic response modeling is required in future studies.     

延边地区汉族和朝鲜族居民脂肪分布与代谢异常的关系

目的:了解延边地区朝鲜族和汉族居民的脂肪分布特征及其与血压、血脂及血糖的关系。方法:于2006-08-8/17在延边地区九龙和翁声社区随机选择40～60岁朝鲜族和汉族常住居民2378名进行内脏脂肪率和体脂肪率以及血压、血脂、血糖等生化指标的检测。调查以健康体检形式进行,①内脏脂肪和体脂肪率测定采用日本TANITA株式会社生产的BC-600型体成分计测定,并且按其判定标准确定超过标准者[内脏脂肪率≥15%(男)、≥10%(女),体脂肪率(40～59岁)≥23%(男)、≥36%(女),体脂肪率(≥60岁)≥25%(男)、≥37%(女)]。②取清晨空腹(禁食12h)静脉血,采用日立-7600-010全自动生化分析仪测量血清总胆固醇、三酰甘油、高密度脂蛋白胆固醇、空腹血糖等指标。③高血压的诊断标准:收缩压≥140mmHg(1mmHg=0.133kPa)及或舒张压≥90mmHg。④血脂异常的诊断标准:总胆固醇≥5.72mmol/L,三酰甘油≥1.7mmol/L,高密度脂蛋白胆固醇<0.90mmol/L(男)、<1.0mmol/L(女)。⑤高血糖的诊断标准:空腹血糖≥6.1mmol/L。结果:①汉族男性的内脏脂肪率和体脂肪率均值分别为(10.51±3.66)%和(22.70±4.85)%,朝鲜族男性分别为(9.16±3.81)%和(20.28±5.02)%,汉族均高于朝鲜族(P<0.01);汉族女性的内脏脂肪率和体脂肪率分别为(6.22±2.27)%和(35.31±5.65)%,朝鲜族女性分别为(5.88±2.19)%和(34.00±5.72)%,汉族均高于朝鲜族(P<0.01)。②汉族男性的内脏脂肪率和体脂肪率超标率分别为12.1%和45.8%,朝鲜族男性分别为7.8%和28.6%,汉族均高于朝鲜族(P<0.05);汉族女性的内脏脂肪率和体脂肪率超标率分别为6.7%和47.9%,朝鲜族女性分别为3.8%和37.3%,汉族均高于朝鲜族(P<0.05)。③Logistic逐步回归分析结果表明,内脏脂肪率与民族、性别、年龄、高血压、高三酰甘油血症和高血糖有密切关系;体脂肪率与民族、性别、高血压、高三酰甘油血症、低高密度脂蛋白血症和高血糖有密切的关系。结论:①延边地区汉族居民内脏脂肪率和体脂肪率平均水平及其超标率明显高于朝鲜族。②内脏脂肪率和体脂肪率均与民族、性别、年龄(体脂肪率除外)、高血压、高三酰甘油血症和高血糖相关。     

The effect of continuous subcutaneous insulin infusion on cardiac performance during exercise in insulin-dependent diabetics

To assess the effects of improved glycaemic control on the right and left ventricular ejection fraction (RVEF and LVEF), we performed radionuclide angiocardiography at rest and during exercise in nine insulin-dependent diabetics with a diabetes duration between 2 and 35 years (mean 12 years) and in 10 control subjects. The diabetics were investigated before and after 7 days' treatment with continuous subcutaneous insulin infusion (CSII). The diabetics had a significantly smaller rise in exercise-induced LVEF during normoglycaemia than in the hyperglycaemic state. In contrast to the control subjects, the diabetics, independent of glycaemic control, did not increase the end-diastolic volume and did not decrease the end-systolic volume during exercise. Our data indicate a preclinical abnormal left ventricular function in young diabetics without long-term diabetic complications. The dysfunction seems unrelated to changes in the loading of the heart and appears to be caused by decreased contractile reserve of the myocardium.     

Comparison between reference values for 201Thallium uptake and washout from the myocardium after exercise and after dipyridamole

Summary. A slow washout of ²⁰¹Thallium has a high diagnostic and prognostic value for coronary artery disease. The aim of the present work was to contribute with reference data on ²⁰¹T1 uptake and washout from the myocardium. With a quantitative method using circumferential profiles and interpolative background subtraction we performed ²⁰¹T1 myocardial imaging in two groups of subjects with a low probability of coronary artery disease. Washout in per cent is defined as (1-D/I) 100, where D is the delayed uptake rate and I the initial uptake rate. In group A (n=16) myocardial hyperaemia was induced by maximal exercise, in group B (n=15) by intravenous infusion of dipyridamole. In group A, the mean washout was 52%, and in group B it was 34% (P < 0.001). The delayed uptake rate D was significantly higher after dipyridamole, 58.4 cps, than after exercise, 44.5 cps (P < 0.05). There was no significant difference in I between the two groups. The findings regarding D and I explain that the washout is slower after dipyridamole than after exercise, as the mean D/I ratio was 0.48 in group A and 0.66 in group B (P < 00.1).     

Magnetoencephalography is more successful for screening and localizing frontal lobe epilepsy than electroencephalography

PURPOSE: The diagnosis of frontal lobe epilepsy may be compounded by poor electroclinical localization, due to distributed or rapidly propagating epileptiform activity. This study aimed at developing optimal procedures for localizing interictal epileptiform discharges (IEDs) of patients with localization related epilepsy in the frontal lobe. To this end the localization results obtained for magnetoencephalography (MEG) and electroencephalography (EEG) were compared systematically using automated analysis procedures. METHODS: Simultaneous recording of interictal EEG and MEG was successful for 18 out of the 24 patients studied. Visual inspection of these recordings revealed IEDs with varying morphology and topography. Cluster analysis was used to classify these discharges on the basis of their spatial distribution followed by equivalent dipole analysis of the cluster averages. The locations of the equivalent dipoles were compared with the location of the epileptogenic lesions of the patient or, if these were not visible at MRI with the location of the interictal onset zones identified by subdural electroencephalography. RESULTS: Generally IEDs were more abundantly in MEG than in the EEG recordings. Furthermore, the duration of the MEG spikes, measured from the onset till the spike maximum, was in most patients shorter than the EEG spikes. In most patients, distinct spike subpopulations were found with clearly different topographical field maps. Cluster analysis of MEG spikes followed by dipole localization was successful (n = 14) for twice as many patients as for EEG source analysis (n = 7), indicating that the localizability of interictal MEG is much better than of interictal EEG. CONCLUSIONS: The automated procedures developed in this study provide a fast screening method for identifying the distinct categories of spikes and the brain areas responsible for these spikes. The results show that MEG spike yield and localization is superior compared with EEG. This finding is of importance for the diagnosis and preoperative evaluation of patients with frontal lobe epilepsy.     

The localization of spontaneous brain activity: first results in patients with cerebral tumors.

Objective: From EEG studies, it is known that structural brain lesions are accompanied by abnormal rhythmic electric activity. With the better spatial resolution of MEG, MEG dipole analysis can extend the knowledge based on EEG power spectra. This study presents the first results of a completely automatic analysis method applied to spontaneous MEG.Methods: Spontaneous MEG data of 5 patients with cerebral brain tumors and 4 controls were collected using a whole-head MEG system. Signals were bandpass-filtered with cut-off frequencies according to standard EEG bands. A moving dipole model was fitted to samples with at least twice the average sample power. Dipoles explaining 90% or more of the magnetic variance were projected onto a matched MR scan.Results: In controls, dipole distributions are symmetrical with respect to the mid-sagittal plane whereas distributions in patients often are asymmetrical to it. Dipoles describing gamma activity were located contralateral, and dipoles describing delta and theta activity were located ipsilateral to lesions.Conclusions: The automatic method gives plausible 3-dimensional information about generator foci of abnormal slow waves and other rhythms with respect to lesion foci and thereby adds physiological knowledge to that derived from EEG power spectra.     

冠状动脉搭桥术早期并发症及死亡率(附196例报告)

1985年1月～1987年12月作者于荷兰格罗宁根医学科学院心胸外科主做了196例冠状动脉搭桥术。术后早期死亡2例(1.0％)、内出血3例(1.5％)、胸骨裂开2例(1.0％)、心律紊乱40例(20.4％)、围手术期心肌梗塞5例(2.6％),本文就术后早期并发症进行了讨论。     

Apports des explorations vasculaires ultrasonores à l''étude des néphropathies chez l''enfant

The proximity of child's kidneys from the cutaneous surface allows a particularly sensitive exploration by doppler sonography, which in addition has the major advantage of being a non-invasive, non-irradiating and painless technique. However there are two limitations to this technique: the lack of cooperation of some children and the still limited availability of high quality equipment in intensive care units. Indeed most of the applications described in this paper (ie. pyelonephritis, renovascular hypertension, tumors, acute renal insufficiency and renal vein thrombosis) require, besides an experienced operator, expensive power doppler equipment including high frequency and high resolution probes.     

Cleaning effectiveness of chewing sticks among Tanzanian schoolchildren.

The oral hygiene of habitual chewing stick and toothbrush users who participated in an oral health education (OHE) programme in schools was evaluated. The study comprised all chewing stick users (n = 45) in standard 4 in 8 randomly selected experimental schools and all chewing stick users (n = 17) in standard 4 in 4 randomly selected control schools. Each chewing stick user was randomly matched with a toothbrush user of the same sex, age and school. Their ages ranged from 10 to 13 years with a mean of 11.5 years. The children in standard 4 of the 8 experimental schools received OHE. Among many topics aiming to improve oral health of children, the practice of systematic brushing was taught. The children practised weekly brushing sessions in schools under the supervision of instructed teachers. At baseline, the chewing stick users exhibited statistically significant more plaque, but their gingival condition was comparable with their matched toothbrush counter-parts. After 3 months, the chewing stick and the toothbrush users in the experimental schools, had reduced their plaque and gingival bleeding scores significantly to the same extent, whereas no substantial changes in oral hygiene occurred in the control group. The findings show that schoolchildren who participated in a school programme that emphasizes effective toothbrushing were able to improve their oral hygiene regardless of whether they were habitual chewing stick or toothbrush users.