Identification and characterization of neurons with tremor-frequency activity in human globus pallidus

 Many previous studies have demonstrated the existence of neurons with tremor-frequency activity (”tremor cells”) in the thalamus of Parkinson’s disease (PD) patients and these neurons are presumed to play a role in the pathogenesis of tremor. Since a major input to motor thalamus (Voa and Vop) is from the internal segment of the globus pallidus (GPi), neurons with tremor-frequency activity in motor thalamus may receive input from neurons in GPi. The aim of this study was to quantify the characteristics of tremor cells in human globus pallidus. In three PD patients with tremor undergoing microelectrode exploration of the globus pallidus prior to pallidotomy, 228 neurons were sampled, and 28 (12.3%) were identified to fire at the same frequency as the tremor. These ”tremor cells” were located in the ventral portion of GPi. Autocorrelogram analysis of the sampled spike trains of these 28 tremor cells was carried out over sequential 10-s time segments, and autocorrelograms showing maximal oscillatory activity were graded from 0 to 10. Average tremor cell oscillation grades ranged from 6.8 to 7.8, similar to those reported in the MPTP-induced primate model of parkinsonism. The average tremor cell oscillation grade varied between patients, as did the clinical measures of tremor severity. Tremor cells had oscillations in spike discharges at the same average frequency (4.2–5.2 Hz) as the patient’s tremor determined from the electromyogram and accelerometry records of one or more limbs (4.0–5.4 Hz), and the individual values were correlated (r ²=0.73) over the total range (3.7–5.6 Hz). The results of this study demonstrate the presence of neurons with 4–6 Hz tremor-frequency activity in GPi, supporting a role of the globus pallidus in the production of rest tremor in PD patients. Received: 27 February 1996 / Accepted: 18 October 1996     

人胎阑尾IAPP-、SS-及5-HT免疫反应性细胞的免疫组织化学研究

为了探讨胰岛淀粉样多肽，在胎阑尾中的个体发及其与其他生物活性物质的关系，用免疫组织ＰＡＰ法，对３６例１２－３８周人胎阑尾中ＩＡＰＰ免疫反应性细胞，生称抑素ＩＲ细胞５－羟色胺－ＩＲ细胞进行定位研究。结果表明，肥１２周，阑尾上皮中已可见到ＳＳ－ＩＲ细胞，而ＩＡＰＰ－及５－ＨＴ－ＩＲ细胞于１４周才见到。在整个胎期，阑尾中的ＩＡＰＰ－及ＳＳ－ＩＲ细胞始络分散存在，数量较少，而５－ＨＴ－ＩＲ细胞数量随胎龄增     

Expression of a 32-kDa ligand for the CD40 antigen on activated human T lymphocytes

To identify the ligand(s) of the human CD40 antigen, a cDNA encoding the extracellular domain of the CD40 antigen was fused to a cDNA encoding the constant region (Fc) of human IgGl. The CD40-Fc fusion protein was able to specifically bind to CD4⁺ and various CD8⁺ T cell clones activated with immobilized anti-CD3. The ¹²⁵I-labeled CD40-Fc fusion protein bound anti-CD3 activated CD4⁺ T cell clone (MT9) with an equilibrium dissociation constant (Ka) of 10-20 nM. The human CD40-binding protein expressed on the cell surface of activated T lymphocytes is a monomeric protein of ≈ 32 kDa. Minor components of 29 kDa and 17 kDa were also detected. A small proportion of CD4+ and CD8⁺ blood mononuclear T cells activated by anti-CD3 expressed the CD40 ligand but its detection was best observed following depletion of B cells. Addition of B cells to purified T cells abolished the binding of CD40-Fc obtained after anti-CD3 activation.     

Atrial natriuretic peptide in human urine

Summary A highly sensitive radioimmunoassay to measure atrial natriuretic peptide (ANP) concentration in urine has been established, and its clinical usefulness is presented. ANP in urine was stable at 4° C for several days and was easily measured by our radioimmunoassay. The average ANP excretion in 65 healthy persons was 25.0±1.4 ng/day (mean ± SEM) and the fractional excretion of ANP was 0.7±0.05%. In 14 patients with congestive heart failure, the average ANP excretion was 119.2±29.4 ng/day, which decreased to 53.3±11.0 after successful treatment.Abbreviations ANP atrial natriuretic peptide - hANP human atrial natriuretic peptide - RIA radioimmunoasay - NSB non specific bound - FE_ANP the fractional excretion of atrial natriuretic peptide - FE_Na the fractional excretion of sodium - SIADH the syngrome of inappropriate secretion of antidiuretic hormone     

The effects of head and trunk position on torsional vestibular and optokinetic eye movements in humans

We measured torsional vestibular and optokinetic eye movements in human subjects with the head and trunk erect, with the head supine and the trunk erect, and with the head and trunk supine, in order to quantify the effects of otolithic and proprioceptive modulation. During active head movements, the torsional vestibulo-ocular reflex (VOR) had significantly higher gain with the head upright than with the head supine, indicating that dynamic otolithic inputs can supplement the semicircular canal-ocular reflex. During passive earth-vertical axis rotation, torsional VOR gain was similar with the head and trunk supine and with the head supine and the trunk erect. This finding implies that static proprioceptive information from the neck and trunk has little effect upon the torsional VOR. VOR gain with the head supine was not increased by active, self-generated head movement compared with passive, whole body rotation, indicating that the torsional VOR is not augmented by dynamic proprioceptive inputs or by an efference copy of a command for head movement. Viewing earth-fixed surroundings enhanced the torsional VOR, while fixating a chair-fixed target suppressed the VOR, especially at low frequencies. Torsional optokinetic nystagmus (OKN) evoked by a full-field stimulus had a mean slow-phase gain of 0.22 for 10°/s drum rotation, but gain fell to 0.06 for 80°/s stimuli. Despite this fall in gain, mean OKN slow-phase velocities increased with drum speed, reaching maxima of 2.5°/s–8.0°/s in our subjects. Optokinetic afternystagmus (OKAN) was typically absent. Torsional OKN and OKAN were not modified by otolithic or proprioceptive changes caused by altering head and trunk position with respect to gravity. Torsional velocity storage is negligible in humans, regardless of head orientation.Presented in part at the Society for Neuroscience Annual Meeting, October 31, 1989, Phoenix, AZ     

Accuracies of saccades to moving targets during pursuit initiation and maintenance

The overall goals of the studies presented here were to compare (1) the accuracies of saccades to moving targets with either a novel or a known target motion, and (2) the relationships between the measures of target motion and saccadic amplitude during pursuit initiation and maintenance. Since resampling of position error just prior to saccade initiation can confound the interpretation of results, the target ramp was masked during the planning and execution of the saccade. The results suggest that saccades to moving targets were significantly more accurate if the target motion was known from the early part of the trial (e.g., during pursuit maintenance) than in the case of novel target motion (e.g., during pursuit initiation); both these types of saccades were more accuate than those when target motion information was not available. Using target velocity in space as a rough estimate of the magnitude of the extra-retinal signal during pursuit maintenance, the saccadic amplitude was significantly associated with the extra-retinal target motion information after accounting for the position error. In most subjects, this association was stronger than the one between retinal slip velocity and saccadic amplitude during pursuit initiation. The results were similar even when the smooth eye motion prior to the saccade was controlled. These results suggest that different sources of target motion information (retinal image velocity vs internal representation of previous target motion in space) are used in planning saccades during different stages of pursuit. The association between retinal slip velocity and saccadic amplitude is weak during initiation, thus explaining poor saccadic accuracy during this stage of pursuit.     

Visuomotor control within a distributed parieto-frontal network

The aim of this functional magnetic resonance imaging study was to investigate differences in visuomotor control with increasing task complexity. Twelve right-handed volunteers were asked to perform their signature under different degrees of visual control: internally generated movement with closed eyes, signing with open eyes, tracking the line of the projected signature forwards, and tracking the line of the projected signature backwards. There was a gradual onset and disappearance of activation within a distributed network. Parietal, lateral and medial frontal brain areas were activated during all conditions, confirming the involvement of a parieto-frontal system. The weight of activation shifted with increasing task complexity. Internally generated movements activated predominantly the inferior parietal lobule and the ventral premotor cortex, as well as the rostral cingulate area, pre-supplementary motor area (pre-SMA) and SMA proper. Opening the eyes reduced SMA and cingulate activation and activated increasingly the occipito-parietal areas with higher task complexity. Visually guided movements produced an activation predominantly in the superior parietal lobule and dorsal premotor cortex. This study bridges human activation studies with the results of neurophysiological studies with monkeys. It confirms a gradual transition of visuomotor control with increasing task complexity within a distributed parieto-frontal network.     

正常人血小板介电谱的实验研究

在100KHz～110MHz范围内,测量人血小板的介电谱,分析了人血小板对交流电场的介电响应的数据特征。利用频域阻抗技术首次测量了正常人血小板交流阻抗,绘制血小板的介电常数和电导率与电场频率的关系曲线。建立了人血小板的介电谱和Cole-Cole图,明确了人血小板的介电频响的数据特征。在射频电场中,人血小板的介电常数和电导率具有频率依赖性,血小板介电谱具有两个特征频率:第一特征频率fC1为6.66MHz,第二特征频率fC2为9.81MHz。     

Mucosal bromodomain-containing protein 4 mediates aeroallergen-induced inflammation and remodeling

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Dual function of Langerhans cells in skin TSLP-promoted TFH differentiation in mouse atopic dermatitis

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