Hypoplasia of the cerebellar vermis and corpus callosum in thrombocytopenia with absent radius syndrome on MRI studies

Thrombocytopenia with absent radius (TAR) syndrome is infrequently (7%) associated with mental retardation. In those cases, the mental deficiency is presumed to be a consequence of intracranial hemorrhage due to the thrombo-cytopenia. We report on 2 infants with TAR syndrome. One had developmental delay with evidence of cerebral dysgenesis by magnetic resonance imaging (MRI). Such findings have not been noted in the literature, but may not have been investigated in most cases. The other infant with TAR syndrome, who has had normal psychomotor development, has a normal brain on MRI scan. Detailed neuroimaging studies, preferably MRI, should be considered in the evaluation of patients with TAR syndrome, especially when there are documented signs of developmental delay, with or without a history of intracranial hemorrhage. © 1994 Wiley-Liss, Inc.     

以傅立叶频谱滤波为手段的振荡电位波形分离方法

为克服传统方法(Calliper-square)和带通放大器在测量振荡电位(OPs)中的不足,应用计算机傅立叶频谱滤波技术,从ERG中分离出振荡电位波形。分离出的OPs能够摆脱a-波,b-波对它的影响而独立地表现出来,使得对OPs的测量变得直观、方便、准确,并把对ERG、OPs的研究,从时域分析扩展到频域分析。     

Insulin Minimal Model Indexes and Secretion: Proper Handling of Uncertainty by a Bayesian Approach

The identification of the insulin minimal model (MM) for the estimation of insulin secretion rate (ISR) and physiological indexes (e.g. beta-cell sensitivity) requires the knowledge of C-peptide (CP) kinetics. The four parameters of the two-compartment model of CP kinetics in a given individual can be derived either from an additional bolus experiment or, more frequently, from a population model. However, in both situations, the CP kinetics is uncertain and, in MM identification, it should be treated as such. This paper shows how to handle CP kinetics uncertainty by using a Bayesian methodology. In seven subjects, MM indexes and ISR were estimated together with their confidence intervals, using either the bolus data or the population model to assess CP kinetics. The two main results that arise from the application of the new methodology are: (i) the use of the population model in place of the bolus data to determine CP kinetics does not affect, on average, the point estimates of ISR profile and MM parameters but only the confidence intervals which becomes wider (less than 50%); (ii) in both the bolus and population situation neglecting the uncertainty of CP kinetics, as done in MM literature so far, introduces no bias, on average, on point estimates of MM indexes but only an underestimation of confidence intervals.     

Multipoint linkage mapping of the Xq25-q26 region in a family affected by the X-linked lymphoproliferative syndrome

We have performed, in a large Swiss family, a study of linkage between various DNA markers in the Xq24-27 region and the locus for the X-linked lymphoproliferative syndrome (XLP). Our results indicated that the marker DXS37 in Xq25-q26 is genetically linked to the XLP syndrome. The multipoint linkage analysis showed that the disease locus is distal to DXS11, but proximal to the hypoxanthine phosphoribosyl-transferase gene (HPRT).     

Molecular characterization of a 10-kDa buckwheat molecule reactive to allergic patients' IgE

BACKGROUND: Using the sera from buckwheat (BW)-allergic patients, several putative causative molecules were reported. However, few molecules were determined on the molecular structure. We demonstrated in 2000 that the major allergen with 24 kDa (BW24KD) is a legumin-like storage protein. OBJECTIVE: The aim of this study was to isolate and characterize further a major allergen with 10 kDa by molecular cloning. METHODS AND RESULTS: Buckwheat allergens were identified by immunoblotting analysis using sera from 14 allergic and two nonallergic individuals. We identified a protein with 10 kDa (BW10KD) that reacted with immunoglobulin E (IgE) more strongly than with IgG and IgA in 57% of the allergic patients but not with IgE in nonallergic individuals. Analyses were performed by N-terminal amino acid sequencing and molecular cloning. Physiological significance was assessed by an immunoblotting experiment showing that the reactivity of an allergic patient's serum IgE to BW10KD was competitively inhibited by natural BW extracts. CONCLUSION: Molecular cloning experiments indicated that BW10KD as a BW allergen was a member of the 2S-albumin multigene family.     

一种独立成分分析的鲁棒算法及其在脑磁图数据分析中的应用

独立成分分析是一种新的信号处理统计方法。被广泛用于各个领域。在信号分析中面临的难题是：源信号的不同特性（既包括超高斯信号又包括亚高斯信号）；未知的独立源数目；传感器信号受到较大的加性噪声污染。针对以上难题，本文提出了一种独立成分分析的鲁棒算法。该方法先对观测数据作预处理，将包含噪声的高维传感器观测信号降维分解到信号子空间和噪声子空间。利用交叉验证法估计出独立源的数目（解决了独立成分分析本身不能确定源数目的缺陷）；然后利用快速稳定的FastICA算法分离独立成分。通过人工合成的数据和实际的脑磁图数据分析。验证了这种方法的功效。     

Morphomechanics of the humero-ulnar joint: II. Concave incongruity determines the distribution of load and subchondral mineralization

Background: A deeper joint socket (concave incongruity) is found at most angles of flexion of the humero-ulnar joint and maintained over a wide range of physiological loading. It is, however, unclear how far this incongruity affects the distribution of load and subchondral mineralization of this joint as compared with a congruous configuration. Methods: Two nonlinear, axisymmetrical finite element models with two cartilage layers were constructed, one congruous and one incongruous, with a joint space of realistic magnitude. The distribution of subchondral mineralization was determined by computed tomography osteoabsorptiometry in the same six specimens that were investigated in the first part of the study, and compared with the biomechanical data obtained there and the predictions of the models. Results: In the congruous case, the center of the socket is highly loaded, whereas the periphery does not experience mechanical stimulation. A central bone density maximum is predicted. With concave incongruity the position of the contact areas shifts from the joint margin towards the center as the load increases, and the peak stresses are considerably lower. A bicentric ventro-dorsal distribution pattern of subchondral mineralization is predicted, and this is actually found in the six specimens. Conclusions: Concave incongruity is shown to determine load transmission and subchondral mineralization of the humero-ulnar joint. It is suggested that this shape leads to a more even distribution of stress, provides intermittent stimulation of the cartilaginous tissue, and has beneficial effects on the metabolism, nutrition, and lubrication of the articular cartilage during cyclic loading. © 1995 Wiley-Liss, Inc.     

T cell receptor γδ repertoire is skewed in cerebrospinal fluid of multiple sclerosis patients: molecular and functional analyses of antigen-reactive γδ clones

To study the relevance of γδ T cells in multiple sclerosis (MS) we analyzed the T cell receptor (TCR) γδ repertoire and the antigen reactivity of γδ clones isolated from cerebrospinal fluid (CSF). In T cell cultures derived from CSF we found an increased percentage of Vδ1⁺ cells as compared to peripheral blood of the same donors. Phenotypic analysis of cells from MS CSF with Vγ- and Vγ-specific monoclonal antibodies (mAb) showed that the Vγ1 chain is most frequently associated with γ chains belonging to the VγI family. Sequence analysis of TCR genes revealed heterogeneity of junctional regions in both δ and γ genes indicating polyclonal expansion. γδ clones were established and some recognized glioblastoma, astrocytoma or monocytic cell lines. Stimulation with these targets induced serine esterase release and lymphokine expression characteristic of the T_H0-like phenotype. Remarkably, these tumor-reactive γδ cells were not detected in the peripheral blood using PCR oligotyping, but were found in other CSF lines independently established from the same MS patient. Altogether, these results demonstrate that in the CSF there is a skewed TCR γδ repertoire and suggest that γδ cells reacting against brain-derived antigens might have been locally expanded.     

Mathematical three-dimensional solid modeling of biventricular geometry

The characterization of regional myocardial stress distribution has been limited by the use of idealized mathematical representations of biventricular geometry. State-of-the-art computer-aided design and engineering (CAD/CAE) techniques can be used to create complete, unambiguous mathematical representations (solid models) of complex object geometry that are suitable for a variety of applications, including stress-strain analyses. We have used advanced CAD/CAE software to create a 3-D solid model of the biventricular unit using planar geometric data extracted from anex vivo canine heart. Volumetric analysis revealed global volume errors of 4.7%, −1.3%, −1.6%, and −1.1% for the left ventricular cavity, right ventricular cavity, myocardial wall, and total enclosed volumes, respectively. Model errors for 34 in-plane area and circumference determinations (mean ±SD) were 5.3±6.7% and 3.8±2.7%. Error analysis suggested that model volume errors may be due to operator variability. These results demonstrate that solid modeling of theex vivo biventricular unit yields an accurate mathematical representation of myocardial geometry which is suitable for meshing and subsequent finite element analysis. The use of CAD/CAE solid modeling in the representation of biventricular geometry may thereby facilitate the characterization of regional myocardial stress distribution.