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.     

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.     

Heart rate analysis in 24 patients treated with 150 mg amitriptyline per day

Twenty-four patients treated with 150 mg amitriptyline per day for an episode of major depression underwent a standardized heart rate analysis (HRA) before therapy and after 14 days. The battery of cardiovascular reflex tests included the determination of the coefficient of variation (CV) while resting and during deep respiration, a spectral analysis of heart rate, the heart rate response to standing, and the Valsalva manoeuvre. The results of the initial HRA did not differ from a group of 24 normal control subjects matched for age and sex. On day 14 of treatment the patients showed significantly reduced values of heart rate variability in all tests (P<0.0001), probably due to the anticholinergic side effects of amitriptyline. Heart rate increased form 78.1 to 93.6 bpm on average (P<0.0001). Abnormal CV at rest was registered in 96% of the patients; during deep respiration 29% showed abnormal CV results. An abnormal spectral analysis was found in 100% of the cases (low frequency peak: 42%, mid-frequency peak: 100%, high frequency peak: 79%). The heart rate response to standing was abnormal in 75% and the Valsalva test in 33% of the cases. Eighty-eight percent of the patients fulfilled the criteria of a cardiovascular autonomic neuropathy under the conditions of amitriptyline therapy. As yet, the consequences of these changes for the patients have not been sufficiently elucidated.     

埃塞俄比亚德布拉巴汗地区盲目分析

埃塞俄比亚德布拉巴汗市医院眼科门诊病人１４３６人中查出盲目患者１６８人，占门诊病人的１１．７％。其中双眼盲６７人，占门诊病人的４．６７％，占盲人的３９．８８％；单眼盲１０１人，占门诊病人的７．０３％，占盲人的６０．１２％。通过分析，初步找出了在埃塞的三大致盲病因，即白内障、青光眼和眼外伤。其中白内障具有重要的开盲意义。     

正常闪光视网膜电图的频域分析

应用快速傅里叶转换技术对正常视网膜电图进行频域分析，发现其ａ、ｂ波的优势频及能量集中在５－７５Ｈｚ；与ＯＰＳ波的分离点为７７ＨＺ，从而提出单纯记录ａ、ｂ波及ＯＰＳ波各自的较理想的通频带。     

Decision making in diagnostic radiology

Radiology can be more interesting if the principles of decision making are understood and used to the advantage of the radiologist, referring clinician and patient. This article seeks to revise the principles that radiologists use intuitively. Particular emphasis is placed on the importance of the pre-test probability, as it can be shown to: (i) vary with the referral pool of patients; (ii) be a major determinant of the amount of additional information gained from the test; (iii) alter the sensitivity and specificity of the test; and (iv) determine largely the significance of a positive or negative test result. An investigation helps a clinician by providing information that will move the probability of disease above an action threshold or below its exclusion threshold. If this does not occur as a result of one study, another is selected. This article also describes the factors involved in such a decision tree analysis, as well as discussing the reasons for both selecting a particular examination and deciding when a test should not be performed.