Comparison between isoprenaline infusions and bolus injections to assess β-adrenoceptor function in man,with special reference to cardiac contractility and the influence of autonomic reflexes

The present study was performed to characterize cardiovascular responses to isoprenaline and the influence of autonomic reflexes on these reponses. Nine healthy volunteers received infusions and bolus injections of isoprenaline before and after ‘autonomic blockade’ produced by intravenous atropine 0.04 mg kg^-1 and clonidine 300 μg. Heart rate, blood pressures, systolic time intervals and various echocardiographic measures of cardiac contractility were registered. No significant differences in responsiveness to isoprenaline were seen when infusions were repeated on the same day without ‘autonomic blockade’. After ‘blockade’, Δ responses at 1 nmol 1^-1 isoprenaline (infusions) were increased for diastolic blood pressure and decreased for systolic blood pressure and stroke volume. Bolus injections of 2 μg isoprenaline caused enhanced Δ responses after ‘autonomic blockade’ of diastolic blood pressure, left ventricular diameter in systole, ventricular circumferential fibre shortening, mean posterior wall velocity (V_{mean pw}), stroke volume, systemic vascular resistance, electromechanical systole (QS₂) and pre-ejection period. Systolic blood pressure decreased, in contrast to a small increase without ‘blockade’. These findings are explained by differences in haemodynamic effects of isoprenaline and by the dependence of responses on reflexes when isoprenaline is administered in different ways. When heart rate was increased by bolus doses of atropine, in the presence of β-blockade (propranolol), pre-ejection period and left ventricular diameter in systole were unaffected, and V_{mean pw} and ventricular circumferential fibre shortening showed only small increases (compared with alterations induced by isoprenaline). However, left ventricular ejection time, QS₂ and ejection time (by echocardiography), were markedly dependent on heart rate alterations. Thus, pre-ejection period, left ventricular diameter in systole V_{mean pw} and ventricular circumferential fibre shortening are parameters which can be useful in order to evaluate cardiac β-adrenoceptor sensitivity in vivo in man.     

心肌梗死患者左室舒张功能评价方法的研究

探讨心肌梗死（ＭＩ）患者左室舒张功能的评价方法及临床应用。方法：采用脉冲多普勒超声心动 图技术检测５０例正常人和５０例ＭＩ患者的左房收缩时间间期（ＬＡＳＴＩ）。包括左房射血前期（ＡＰＥＰ）、校正心房射血 前期（ＡＰＥＰＣ）和左房射血期（ＡＥＴ）;肺静脉Ｓ峰、Ｄ峰、Ａ峰;二尖瓣血流Ｅ峰、Ａ峰及Ｅ／Ａ比值。ＭＩ组给予抗舒张 障碍治疗３周后再测量各项指标。结果：ＭＩ组的ＡＰＥＰ、ＡＰＥＰＣ缩短,ＡＥＴ延长;肺静脉Ｓ峰、Ａ峰增大,Ｄ峰减小; 二尖瓣Ｅ峰减小,Ａ峰增大（Ｐ＜０．０１）。ＭＩ组治疗３周后各项指标明显改善（Ｐ＜０．０１）。结论：综合多指标分析能 提高左室舒张功能评价的准确性。     

Supratentorial recurrences of gliomas. Morphological studies in relation to time intervals with astrocytomas

Summary We report 137 recurrent supratentorial astrocytomas. The primary tumours diagnosed on the basis of a grading system with three stages were 72 astrocytomas I and 65 astrocytomas II. In the first group 14% of the recurrences were not changed, 55.5% became astrocytomas II, and 30.5% became glioblastomas. In the second group 55.4% were unchanged, and 44.6% became glioblastomas. The postoperative intervals until reintervention or death were statistically examined. It seems that the recurrence time chiefly depends on the nature of the primary tumour. The transformation of an astrocytoma I to a glioblastoma takes longer than the transformation of an astrocytoma II into a glioblastoma. In about two thirds of all astrocytomas an increase of malignancy is to be expected. From the histological picture it is not possible in an individual case to predict the likelihood or speed of malignant change. With regard to the effect of irradiation the authors conclude that radiotherapy most probably does not produce malignancy.The authors wish to express their gratitude to the founder and organizer of the Institute of Neurosurgery in Budapest, Prof. Dr. L. Zoltán (), for his promotion of these investigations.     

高血压和2型糖尿病对心脏搭桥术后早期心率变异性影响程度的探讨

目的：探究行非体外循环下冠状动脉搭桥术（off-pump coronary artery bypass grafting,OPCABG）患者围术期心率变异性（heart rate variability,HRV）的变化趋势,以及高血压和（或）2型糖尿病（type 2 diabetes mellitus,T2DM）因素对这种趋势的影响程度。方法：回顾性研究2020年12月至2022年3月因冠状动脉粥样硬化性心脏病需要行OPCABG的521名患者住院期间的基线资料与围手术期7 d动态心电图记录的相关指标来反映HRV的早期改变。根据患者既往是否患有高血压和（或）T2DM将患者分为A、B、C、D 4组：A组（患有高血压合并T2DM,n=118）、B组（单纯患有高血压,n=183）、C组（单纯患有T2DM,n=81）、D组（既往无高血压且无T2DM,n=139）。对521名患者行独立样本t检验,观察患者行OPCABG围术期全部窦性心搏RR间期的标准差（standard deviation of NN intervals,SDNN）与相邻正常心动周期差值的均方的平方根（root-mean-squa...     

按GB／T3359用随机样本检验数据判定医疗器械总体质量水平

计量抽样检验目前在中国医疗器械行业应用较少。本文结合两个国外医疗器械标准的实例对GB／T3359在医疗器械标准中的应用进行了解读,并通过与传统的计数抽样检验进行比较,得出医疗器械检验中采用GB／T3359进行计量抽样的优势所在。     

Shrinkage estimation and the use of additional information when calibrating in the presence of random effects

Let x denote a precise measurement of a quantity and Y an inexact measurement, which is, however, less expensive or more easily obtained than x. We have available a calibration set comprising clustered sets of (x,Y ) observations, obtained from different sampling units. At the prediction step, we will only observe Y for a new unit, and we wish to estimate the corresponding unknown x, which we denote by ξ. This problem has been treated under the assumption that x and Y are linearly related. Here, we expand on those results in three directions: First, we show that if we center ξ about a known value c, for example, the mean x‐value of the calibration set, then the proposed estimator now shrinks to c. Second, we examine in detail the performance of the estimator, which was proposed when one or more (x,Y ) observations can be obtained for the new subject. Third, we compare the Fieller‐like confidence intervals, previously proposed, with t‐like intervals based on asymptotic moments of the point estimate. We illustrate and evaluate our procedures in the context of a data set of true bladder‐volumes (x) and ultrasound measurements (Y). Copyright © 2013 John Wiley & Sons, Ltd.     

Age‐dependent biochemical quantities: An approach for calculating reference intervals

Objective. A parametric method is often preferred when calculating reference intervals for biochemical quantities, as non‐parametric methods are less efficient and require more observations/study subjects. Parametric methods are complicated, however, because of three commonly encountered features. First, biochemical quantities seldom display a Gaussian distribution, and there must either be a transformation procedure to obtain such a distribution or a more complex distribution has to be used. Second, biochemical quantities are often dependent on a continuous covariate, exemplified by rising serum concentrations of MUC1 (episialin, CA15.3) with increasing age. Third, outliers often exert substantial influence on parametric estimations and therefore need to be excluded before calculations are made. Material and methods. The International Federation of Clinical Chemistry (IFCC) currently recommends that confidence intervals be calculated for the reference centiles obtained. However, common statistical packages allowing for the adjustment of a continuous covariate do not make this calculation. Results. In the method described in the current study, Tukey's fence is used to eliminate outliers and two‐stage transformations (modulus‐exponential‐normal) in order to render Gaussian distributions. Fractional polynomials are employed to model functions for mean and standard deviations dependent on a covariate, and the model is selected by maximum likelihood. Confidence intervals are calculated for the fitted centiles by combining parameter estimation and sampling uncertainties. Finally, the elimination of outliers was made dependent on covariates by reiteration. Conclusions. Though a good knowledge of statistical theory is needed when performing the analysis, the current method is rewarding because the results are of practical use in patient care.     

Mortality outcomes based on ED qSOFA score and HIV status in a developing low income country

Objective

To evaluate the utility of the quick Sepsis-related Organ Failure Assessment (qSOFA) score to predict risks for emergency department (ED) and hospital mortality among patients in a sub-Saharan Africa (SSA) setting.

Determinants of Intima-Media Thickness in the Young: The ALSPAC Study

ObjectivesThis study characterized the determinants of carotid intima-media thickness (cIMT) in a large (n > 4,000) longitudinal cohort of healthy young people age 9 to 21 years.BackgroundGreater cIMT is commonly used in the young as a marker of subclinical atherosclerosis, but its evolution at this age is still poorly understood.MethodsAssociations between cardiovascular risk factors and cIMT were investigated in both longitudinal (ages 9 to 17 years) and cross-sectional (ages 17 and 21 years) analyses, with the latter also related to other measures of carotid structure and stress. Additional use of ultra-high frequency ultrasound in the radial artery at age 21 years allowed investigation of the distinct layers (i.e., intima or media) that may underlie observed differences.ResultsFat-free mass (FFM) and systolic blood pressure were the only modifiable risk factors positively associated with cIMT (e.g., mean difference in cIMT per 1-SD increase in FFM at age 17: 0.007 mm: 95% confidence interval [CI]: 0.004 to 0.010; p < 0.001), whereas fat mass was negatively associated with cIMT (difference: ?0.0032; 95% CI: 0.004 to ?0.001; p = 0.001). Similar results were obtained when investigating cumulative exposure to these factors throughout adolescence. An increase in cIMT maintained circumferential wall stress in the face of increased mean arterial pressure when increases in body mass were attributable to increased FFM, but not fat mass. Risk factor?associated differences in the radial artery occurred in the media alone, and there was little evidence of a relationship between intimal thickness and any risk factor.ConclusionsSubtle changes in cIMT in the young may predominantly involve the media and represent physiological adaptations as opposed to subclinical atherosclerosis. Other vascular measures may be more appropriate for the identification of arterial disease before adulthood.