Le traitement du signal en électromyographie: mise au point

Automatic analysis of electromyography (EMG) signals, first operated in 1950 with analogic machines, steeply expanded from 1980 when fast computers and worthwhile programs became available. On-line measurement of response area and latency, averaging of low amplitude waves, fast sorting of motor unit potential shape parameters, computation of the “jitter” between two muscle fibers, turns/amplitude and spectral analysis of interferential pattern records, are some examples of programs currently offered in modern EMG machines. Other techniques are still reserved for research purposes: scanning EMG, decomposition of nerve and muscle compound potentials, measurement of the threshold and firing rate of motor units, trace analysis using tracking models. Finally, the credit for artificial intelligence systems (knowledge based systems, fuzzy logic, neuronal networks) is still not clearly stated.     

Sources of P300 attenuation after head injury: Single-trial amplitude, latency jitter, and EEG power

Single trial amplitude, latency jitter, and electroencephalographic (EEG) power were examined as sources of the group difference in averaged P300 amplitude among 15 traumatically brain injured and 20 control individuals in an auditory oddball paradigm. Mean amplitude of the individual trials was highly correlated with the amplitude of the averaged P300, with little additional unique variance attributable to latency jitter or EEG power. The group difference in P300 amplitude was also explained by the mean amplitude of the single trials. These results support the robustness of the event-related potential averaging technique within the paradigm used.     

A solitary plasmacytoma of donor origin arising 14 years after kidney allotransplantation

Summary Allotransplantation of solid organs transfers passenger leucocytes which may give rise to a state of persistent microchimaerism. In this report we describe the case of a patient who developed a solitary plasmacytoma in a transplanted kidney more than 10 years after allografting. The diagnosis was established on the basis of the presence of a monoclonal IgG kappa peak in the serum, and light chain proteinuria, the plasmacytoid features of tumour cells including cell surface expression of IgG, kappa light chains, CD20, CD38 and CD56, the absence of lytic bone lesions and a normal bone marrow biopsy, and the disappearance of the monoclonal IgG peak after graft nephrectomy. A donor origin of the tumour was established by HLA DNA typing of tumour, tumour-free kidney tissue, and peripheral blood leucocytes, respectively.     

An alternative method for significance testing of waveform difference potentials

Guthrie and Buchwald (1991) proposed an ad hoc procedure for assessing the statistical significance of waveform difference potentials that may arise in a variety of psychophysiology research contexts. In our paper, an alternative method is presented and demonstrated that has fewer underlying assumptions than does the Guthrie-Buchwald test and may, therefore, produce better results in some situations. In particular, the test proposed here (a) is distribution free, (b) requires no assumption of an underlying correlation structure (e.g., first-order autoregressive), (c) requires no estimate of the population autocorrelation coefficient, (d) is exact, (e) produces p values for any number of subjects and time points, and (f) is highly intuitive as well as theoretically justifiable. This procedure may be used to carry out multiple comparisons with exact specification or experimentwise error, however, this test is based on permutation principles and may require large amounts of computer time for its implementation.     

56眼饮用天然矿泉水水质分析

本文对我省５６眼矿泉水的地理分布符合国家标准的情况及矿泉水水化学类型进行了统计分析，结果表明：５６眼矿泉水基本遍布全省；其感官指标、污染物指标及微生物指标均符合国家标准；通过对限量指标分析，我省矿泉水属念锶或含偏硅酸或二者兼含；水化学分类以ＨＣＯ３·Ｃａ型居多，其次为ＨＣＯ３－Ｃａ·Ｎａ型。对影响卫生化学性能的决定因子进行相关分析表明：除Ｃａ２＋与Ｍｇ２＋呈正相关外，Ｋ＋与Ｎａ＋及Ｓｒ与Ｈ２ＳｉＯ３之间无相关性     

A guar-enriched wholemeal bread reduces postprandial glucose and insulin responses

We have developed a guar wholemeal bread and tested its physiological efficacy and sensory qualities. The objective of the study was to estimate the optimum concentration of guar in bread required to reduce postprandial glycaemia and insulinaemia without adversely affecting the quality of the bread. Following overnight fasts, 15 normal weight, non-diabetic subjects consumed meals of wholemeal bread alone (controls) and supplemented with guar at three different concentrations (5, 10 and 15% replacement of wheat flour). Blood samples for glucose and insulin analysis were taken preprandially, and at 30 and 60 min after the start of each meal. The acceptability of the wholemeal control and guar breads was assessed using a hedonic scaling method. A significantly lower blood glucose rise at 30 min was found after the 15% guar bread meal compared to the control. Plasma insulin responses at 30 and 60 min were significantly lower after the 10 and 15% guar bread meals compared to the controls. Hedonic scores indicated that the subjects found the 5 and 10% guar breads acceptable and in the case of the 5% variety the mean score was identical to the control. We suggest that a guar concentration of between 5 and 10% replacement of wheat flour (wholemeal or white) should be used for the baking of guar wholemeal bread but further work is needed to define the precise quantity of guar required.     

Optimal Selection of Sib Pairs from Random Samples for Linkage Analysis of a QTL Using the EDAC Test

Percentages of extremely concordant and extremely discordant sib pairs are calculated that maximize the power to detect a quantitative trait locus (QTL) under a variety of circumstances using the EDAC test. We assume a large fixed number of randomly sampled sib pairs, such as one would hope to find in the large twin registries, and limited resources to genotype a certain number of selected sib pairs. Our aim is to investigate whether optimal selection can be achieved when prior knowledge concerning the QTL gene action, QTL allele frequency, QTL effect size, and background (residual) sib correlation is limited or absent. To this end we calculate the best selection percentages for a large number of models, which differ in QTL gene action allele frequency, background correlation, and QTL effect size. By averaging these percentages over gene action, over allele frequency, over gene action, and over allele frequencies, we arrive at general recommendations concerning selection percentages. The soundness of these recommendations is subsequently in a number of test cases.     

Genotype at a major locus with large effects on apolipoprotein B levels predicts familial combined hyperlipidemia

A sample enriched for familial combined hyperlipidemia (FCHL) was examined for evidence of an association between genotype at an apolipoprotein B (apoB) elevating locus defined by complex segregation analysis and FCHL. Complex segregation analysis detected a locus with a large effect on plasma apoB levels and was used to compute the most probable genotype of family members. None of the 35 normolipidemic adults carried a copy of the allele associated with elevated apoB levels, yet 58% of the 109 adults with FCHL carried 1 (29%) or 2 (28%) copies. Two of 28 (7%) normal children had 1 copy of this allele and none had 2 copies, while 88 of 182 (48%) children with FCHL had 1 (26%) or 2 (22%) copies. Further, 4l of 48 (85%) individuals classified as having hyperapobetalipoproteinemia did not carry a copy of this “elevated apoB” allele. Therefore, the presence of the allele associated with elevation of apoB level is highly predictive of FCHL and this association cannot be explained solely by the presence of elevated apoB levels in FCHL, suggesting that the locus controlling apoB levels may play an etiologic role in FCHL. © 1993 Wiley-Liss, Inc.     

A study of the value of electrophoretic and other techniques for typing Acinetobacter calcoaceticus

Forty-four isolates of Acinetobacter calcoaceticus var anitratus collected during hospital outbreaks were studied using polyacrylamide gel electrophoresis (PAGE), plasmid analysis, antibiograms and biochemical tests to determine their degree of similarity. Reproducibility tests were also carried out on the PAGE and biochemical techniques to determine their validity when used to compare bacteria of the same type isolated intermittently. PAGE data was analysed densitometrically and isolates compared using a similarity matrix. All methods were able to subdivide the isolates, but results did not always correlate well between methods. Reproducibility data indicated that careful attention to technique is required when organisms are examined by PAGE sequentially. Results suggest that no single biotyping technique is likely to be adequate and that electrophoretic, biochemical and antibiogram data may complement one another and other epidemiological data in the typing of these organisms.