Cross-spectral analysis of cardiovascular variables in supine diabetic patients

Abstract Cardiovascular autonomic neuropathy in diabetes is associated with a high risk of mortality, which makes its early identification clinically important. An easy method for identification of subjects with autonomic dysfunction would be of clinical benefit.We evaluated the autonomic function in 28 diabetic patients and 21 control subjects recording 12 min time series of heart period (RR) and systolic arterial pressure (SAP, Finapres) during supine rest and 60° head-up tilt. The power of the high (respiratory) and low (LF ~ 0.1 Hz) frequency oscillations was quantified by spectral analysis. The central frequency of the LF oscillations (LF_freq), phase shift, and the transfer function gain between RR interval and SAP fluctuations were provided by cross-spectral analysis, and measured at the point of maximal coherence.In the supine position 15 patients (LF–) displayed atypical LF variability with the LF_freq being shifted towards lower frequencies (about 0.06 Hz). They also showed larger phase angle, lower values or even absence of coherence and smaller transfer function gain between RR and SAP fluctuations. 13 patients (LF+) and the controls showed the LF_freq around 0.1 Hz, higher coherence and transfer function gain values. The orthostatic maneuver induced the expected changes in the spectral parameters (increase in the LF components of both RR and SAP and decrease in the HF variability of RR) into the LF+ patients and all the control subjects and abnormal response in the other 15 LF-patients.These findings indicate that diabetic subjects with uncharacteristic response to the orthostatic test present abnormal LF variability already in the supine position. Crossspectral parameters while supine may be used for the identification of these subjects.     

Fulfillment指数和最终死于某死因概率及其在死因分析中的应用

本文利用1989年哈尔滨市城市居民死因统计资料介绍和讨论了Fulfillment指数和最终死于某死因概率的概念、意义、计算方法及其在死因分析中的应用。     

The yield of head-up tilt testing is not significantly increased by repeating the baseline test

Background and hypothesis: Head-up tilt is widely used in evaluating patients with syncope. Data suggest that baseline tilt without isoproterenol is associated with few ≤ 10%) positive results in normals. However, there is considerable day-today variability in patients with syncope, resulting in low reproducibility. We hypothesized that repeating the baseline tilt would increase the total number of positive responses. Methods: In all, 193 patients with syncope of unknown etiology prospectively underwent serial baseline tilt (Tilt-1 and Tilt-2) at 70° for 25 min on two consecutive days. Results: Of 193 patients, 39(20%) had a positive Tilt-1. Of these, 19 had a positive Tilt-2, (positive concordance rate: 19/39 = 49%). Of 154 patients with a negative Tilt-1, 145 had a negative Tilt-2 (negative concordance rate: 142/151=94%). Only 9 of 154 patients (6%) with a negative Tilt-1 had a positive Tilt-2. Thus, the yield increased from 20% (39/193) after Tilt-1, and to 25% (48/193) after Tilt-1 plus Tilt-2, p = NS. Conclusions: (1) Reproducibility of a positive Tilt-1 is moderate. (2) Reproducibility of a negative Tilt-1 is high. (3) Repetition of tilt in patients with a negative Tilt-1 does not significantly increase the number of positive results.     

Mycotic aortocaval fistula: efficient evaluation by bolus-chase MR angiography

Aortocaval fistula (ACF) is a rare but life-threatening condition. This case report describes the use of bolus-chase gadolinium-enhanced 3D magnetic resonance angiography (MRA) to provide an efficient evaluation of a patient with ACF associated with a mycotic abdominal aortic aneurysm. This case highlights the ability of bolus-chase MRA to provide both the specific diagnosis of ACF as well as the information necessary for extra-anatomic arterial bypass. Bolus-chase MRA is a promising method for the evaluation of patients with this disease entity.     

Motor root conduction block in traumatic brachial plexopathy

A 31-year old man sustained severe left brachial plexus traction injury. Electrical stimulation demonstrated multilevel motor root conduction block, which reversed after a 4-month period. Motor root conduction studies are useful diagnostic and prognostic adjuncts in the management of brachial plexopathy.     

合理调控自动洗片机运行参数--提高照片质量的重要环节

目的初步研究自动洗片机运行参数的调控方法.方法在显影液的一个使用周期中,用标准感光的"样片”,每3d测试一次自动洗片机不同显影温度时输出胶片的密度.选择适当的显影温度,制成调控参数表.结果胶片密度随显影液新旧变化,幅度为0.82.根据调控参数表调整洗片机运行参数后输出胶片的密度变化幅度为0.17,是调整前的20%.胶片的密度变化明显减少.结论根据调控参数表,适时调整洗片机运行参数,可以有效控制洗片机输出胶片的密度.     

用微处理机实现IIR数字滤波

本文叙述如何在微处理机上用分布计算和查表相结合的方法实现数字滤波。     

DIET AND DENTAL HEALTH AS MEASURED BY NHANES I DATA

The NHANES I survey dental data established associations between the consumption of soft drinks, sugars and syrups, sugary desserts and snacks, and high caries scores.     

倒立位暴露后头高位倾斜联合-9.33 kPa下体负压对心血管功能的影响

目的: 观察倒立位暴露后头高位倾斜联合-9.33 kPa的下体负压对心血管功能的影响,进一步探讨下体负压倾斜床模拟航空推拉效应的效果.方法: 8名受试者在下体负压倾斜床上进行"直立位→倒立位→直立位+下体负压(-9.33 kPa)致晕厥/晕厥前状态"的模拟推拉效应试验及"单纯直立位+下体负压(-9.33 kPa) 致晕厥/晕厥前状态"的对照试验,用阻抗法测量试验过程中心率(HR)、血压(BP)、基础阻抗(Z0)、每搏心输出量(SV)、心输出量(CO)及总外周阻力(TPR)等心血管功能指标的变化.结果: 模拟推拉效应试验的下体负压耐受时间显著比对照试验的低(P<0.05).模拟推拉效应试验时,倒立位与直立位对照相比较,受试者HR、Z0显著降低(P<0.01),SV、SI、CO、CI显著升高(P<0.01);在直立位+下体负压暴露时,心血管功能指标的变化与对照试验时的变化类似,即HR、TPR较HUT值显著增高(P<0.05 or P<0.01), SV、SI、CO、SI较HUT值显著降低(P<0.05 or P<0.01).在对照试验时,SBP显著降低(P<0.01).在模拟推拉效应试验时,在直立位+下体负压暴露开始1 min内,DBP、MBP较HUT值显著增高(P<0.05 or P<0.01).结论: 倒立位后,再直立+LBNP暴露的耐受时间显著低于单纯直立+LBNP暴露的耐受时间,下体负压倾斜床可用来模拟推拉效应.     

牵引整复按摩机控制系统的软件设计

论述牵引整复按摩机控制系统的原理和结构。采用VC 语言开发系统应用软件,实现了整机的自动化控制。该系统操作简便、运行可靠、应用效果良好。