Long-term ambulatory monitoring of indirect arterial blood pressure using a volume-oscillometric method

A new portable instrument equipped with a microprocessor was designed for the long-term ambulatory monitoring of indirect arterial pressure in the human finger at desired intervals using a volume-oscillometric technique. All the necessary procedures such as (1) programmed control of cuff pressure, (2) detection of the systolic end-point and the point of maximum amplitude of arterial volume pulsations, (3) reading of the cuff pressures corresponding to these two points, (4) its processing and (5) recording of the systolic and mean pressure together with heart rate on a digital memory integrated circuit were performed automatically. After the monitoring, the data were reproduced and analysed by a conventional personal computer. Simultaneous comparison of the data with direct measurement, operation and evaluation of this instrument, and ambulatory monitoring were carried out. With this instrument noninvasive and accurate monitoring of arterial pressure could be made in unrestricted subjects during daily activities.     

Digital socially acceptable monitoring instrument (s.a.m.i.)

The design of an instrument is described for the purpose of counting the heart beat of a subject while undergoing ‘out-of-the-laboratory experiments’. The instrument consists basically of two units one of which is small, is worn by the subject and counts the subjects heart beats during the experimental period. The other unit is used to display the magnitude of the count at the end of the experimental time. The instrument has a capacity to count over two million heart beats over an experimental period of one week. The theme of the design has been to use commonly available and inexpensive components throughout. The extensive use of integrated circuits also facilitates ease of construction.     

Pre-learning stress differentially affects long-term memory for emotional words, depending on temporal proximity to the learning experience

Stress exerts a profound, yet complex, influence on learning and memory and can enhance, impair or have no effect on these processes. Here, we have examined how the administration of stress at different times before learning affects long-term (24-hr) memory for neutral and emotional information. Participants submerged their dominant hand into a bath of ice cold water (Stress) or into a bath of warm water (No stress) for 3 min. Either immediately (Exp. 1) or 30 min (Exp. 2) after the water bath manipulation, participants were presented with a list of 30 words varying in emotional valence. The next day, participants' memory for the word list was assessed via free recall and recognition tests. In both experiments, stressed participants exhibited greater blood pressure, salivary cortisol levels, and subjective pain and stress ratings than non-stressed participants in response to the water bath manipulation. Stress applied immediately prior to learning (Exp. 1) enhanced the recognition of positive words, while stress applied 30 min prior to learning (Exp. 2) impaired free recall of negative words. Participants' recognition of positive words in Experiment 1 was positively associated with their heart rate responses to the water bath manipulation, while participants' free recall of negative words in Experiment 2 was negatively associated with their blood pressure and cortisol responses to the water bath manipulation. These findings indicate that the differential effects of pre-learning stress on long-term memory may depend on the temporal proximity of the stressor to the learning experience and the emotional nature of the to-be-learned information.     

Reflex sympathetic tachycardia during intravenous infusions in chronic spinal cats.

The reflex tachycardia elicited by rapid intravenous infusions of a blood substitute was studied in 21 chronic cats with spinal sections at C8. All animals could breath spontaneously. The day after section the average resting heart rate (HR) and arterial pressure (AP) were 109 beats/min and 98/67 mmHg, respectively. Vagal blockade with atropine (0.5-0.7 mg/kg iv) was performed prior to each infusion, increasing the average HR To 127 beats/min. In 39 infusions in 21 cats the average increase in HR was 10 beats/min (range from -6 to +22 beats/min). A tachycardia was observed in all but five trials, four of which were obtained in two cats that subsequently responded with a tachycardia. In seven animals the neural circuit mediating the response was partially or totally interrupted by section of several thoracic dorsal roots (T1-T4 or T1-T6) and of the spinal cord at the inferior level of these sections (between T6 and T7). The tachycardia response was progressively reduced and finally abolished by these procedures. These experiments indicate that spinal neural mechanisms are likely to contribute to the phenomenon first described by Bainbridge.     

Physiological characteristics of badminton match play

The present study aimed at examining the physiological characteristics and metabolic demands of badminton single match play. Twelve internationally ranked badminton players (eight women and four men) performed an incremental treadmill test [VO(2peak = )50.3 +/- 4.1 ml min(-1) kg(-1) (women) and 61.8 +/- 5.9 ml min(-1) kg(-1) (men), respectively]. On a separate day, they played a simulated badminton match of two 15 min with simultaneous gas exchange (breath-by-breath) and heart rate measurements. Additionally, blood lactate concentrations were determined before, after 15 min and at the end of the match. Furthermore, the duration of rallies and rests in between, the score as well as the number of shots per rally were recorded. A total of 630 rallies was analysed. Mean rally and rest duration were 5.5 +/- 4.4 s and 11.4 +/- 6.0 s, respectively, with an average 5.1 +/- 3.9 shots played per rally. Mean oxygen uptake (VO(2)), heart rate (HR), and blood lactate concentrations during badminton matches were 39.6 +/- 5.7 ml min(-1) kg(-1) (73.3% VO(2peak)), 169 +/- 9 min(-1) (89.0% HR(peak)) and 1.9 +/- 0.7 mmol l(-1), respectively. For a single subject 95% confidence intervals for VO(2) and HR during match play were on average 45.7-100.9% VO(2peak) and 78.3-99.8% HR(peak). High average intensity of badminton match play and considerable variability of several physiological variables demonstrate the importance of anaerobic alactacid and aerobic energy production in competitive badminton. A well-developed aerobic endurance capacity seems necessary for fast recovery between rallies or intensive training workouts.     

Persistence of spatial memory in the Morris water tank task

Persistence of the spatial memory record was examined in 30 rats overtrained in the working memory version of the Morris water tank task. In Experiment 1, the animal had to find during the acquisition trial an invisible underwater platform randomly located at one of 4 possible sites in the pool. Retention test was performed 1 min, 60 min, 4 h or 24 h later with the same position of the platform and same or changed position of the start. Whereas in the acquisition trials the rats reached the goal after 12 s on average, the latency in the retrieval trials increased with the acquisition-retrieval interval. It was 5 s with the 1-min delay and exponentially approached, but did not quite reach the acquisition trial latency with the 24-h delay. In Experiment 2 the rats were started from the same position of the tank to goal positions changing from trial to trial in a prearranged sequence. There were either 1-h or alternating 1-min and 2-h intervals between the 6 daily trials. The latencies were long during the first trial and whenever the goal changed and short when the goal remained the same as on the previous trial. The latencies were not significantly influenced by intertrial interval in the 1 min to 2 h range. It is concluded that the decay of spatial memory in the water tank task is slow and is little affected by proactive interference.     

Differential effects of active versus passive coping on secretory immunity

This study examined the acute immunological effects of two laboratory stressors, expected to evoke distinct patterns of cardiac autonomic activity; namely an "active coping" time-paced memory test, and a "passive coping" stressful video showing surgical operations. We measured salivary S-IgA, IgA-subclasses (IgA1, IgA2), and secretory component (SC). SC is responsible for the transport of S-IgA across the epithelium, and thus a rate-determining step in S-IgA secretion. Thirty-two male undergraduates were subjected to both stressors and a control video (a didactic television program). The memory test induced a typical "fight-flight" response, characterized by increases in heart rate and blood pressure in association with a decrease in cardiac preejection period (PEP) and vagal tone. The surgical video produced a "conservation-withdrawal"-like response, characterized by an enhanced vagal tone, a decrease in heart rate, and a moderate sympathetic coactivation (as indicated by a shortened PEP and an increased systolic pressure). The memory test induced an increase in the concentration and, to a lesser extent, in the output of S-IgA, IgA], and SC. The output of IgA2 was not significantly affected. For the surgical video, a different pattern emerged: During stressor exposure S-IgA remained unaffected, against the background of a small increase in SC output. However, 10 min after the surgical video S-IgA levels had decreased. This decrease in S-IgA was paralleled by a decrease in IgA1, but not IgA2. We conclude that acute stress can have both enhancing and suppressive effects on secretory immunity, the IgA1 subclass in particular. The mechanisms that underlie these divergent responses may include stressor-specific patterns of autonomic activation.     

Signals Analysis and Clinical Validation of Blood and Oxygen Data in Human Brain

INTRODUCTION Ithadlongbeenbelievedthatthescatteringandabsorptionofnearinfrared throughhumantissuescanonlyofferthesurfaceinformationoftissues〔1〕,butJob-sis〔2〕foundthatinnerinformationofbraincouldbeacquiredwhennearinfraredare usedtoirradiatebrainin1977.Thistechnologyhasstimulatedresearcherstostudy theactivesofhumanbrainwithscatteringofnearinfraredlightandhasdifferent namesindifferenttimes,likenearinfraredspectrum(NIRS),diffusionoftomogra-phy(DOT)andnearinfraredimaging(NIRI).Recentde…     

龚氏记忆成套测验(儿童本)的初步编制

目的 :以当代认知心理学和认知神经科学关于人类记忆的重要研究成果为指导 ,编制一种用于记忆评估的成套测验并在儿童样本中初步试用。方法 :龚氏记忆成套测验由 10个分测验构成 ,分别涉及听觉和视觉即时记忆 ,听觉和视觉延时记忆以及工作记忆等方面的内容。研究样本取自湖南长沙市和湖南沅江市在校学生 ,总计 2 85人 (男 137人 ,女 14 8人 ) ,年龄 7～ 15岁 ,平均年龄 11.11± 2 .38岁。结果 :(1)项目分析显示 ,各分测验的平均难度指数为 0 .5 6 ,平均鉴别指数为 0 .35。 (2 )各分测验的重测相关系数为 0 .6 5～ 0 .97;除图片记忆分测验外 ,其余各分测验的分半相关系数 ,Cronbachα系数及概化系数均在 0 .80左右。 (3)探索性因素分析提取出 4个特征根大于 1的因子 ,4因子累计解释变异的 77.5 2 %。 (4)本测验与WMS -RC的理解记忆、视觉再生、背数 3个分测验相关较高 ,与WMS -RC的联想学习分测验有低至中度相关 ,与WMS -RC图片回忆分测验相关较低。 (5 )所有记忆指数及大多数分测验成绩与语文、数学成绩呈显著正相关 ,其中 ,听觉记忆成绩与语文成绩的相关高于与数学成绩的相关 ,视觉记忆成绩及工作记忆与数学成绩的相关高于与语文成绩的相关。结论 :龚氏记忆成套测验的项目难度和区分度符合心理测量学要     

Ambulatory instrument for monitoring indirect beat-to-beat blood pressure in superficial temporal artery using volume-compensation method

A portable instrument, based on a volume-compensation technique, is designed for ambulatory monitoring of indirect beat-to-beat blood pressure (BP) in the superficial temporal artery. The instrument consists of a small disc-type cuff and a portable unit carried by the subject. Several components are integrated in the cuff for applying counter-pressure to the artery, i.e. a reflectance-type photo-plethysmographic sensor for arterial volume detection, a pressure sensor for cuff pressure P_c measurement and a nozzle flapper-type electro-pneumatic convertor for controlling P_c. The portable unit includes volume servo control circuitry and a microprocessor-based signal-processing and recording unit. This automatically performs all the necessary measurement procedures and stores into a memory IC element the processed systolic, mean and diastolic blood pressure data, together with pulse intervals on a beat-to-beat basis from the servo-controlled P_c (indirectly measured BP waveform). With this instrument, momentary changes in BP during ambulatory situations such as bicycle ergometer exercise and daily activities including motorway driving are successfully recorded. From the results of simultaneous measurement of the subject's posture changes, the effect of posture change on blood pressure, e.g. baroreceptor-cardiac reflex, is also clearly demonstrated.     

Development of an instrument to assess clinicians' Recognition memory using a videotaped stimulus interview

This study represents the development of an instrument to assess clinicians' memory using a videotaped counseling interview. The instrument, called the Recognition Checklist (RC), consists of 60 items of information based on the content presented by the client on the stimulus tape. Initial findings indicated that this instrument has promising reliability and validity and warrants further development and application to the study of clinicians' memory of the interview process and interviewing skill training.     

A single bout of exercise with a flexible pole induces significant cardiac autonomic responses in healthy men

OBJECTIVES:

Flexible poles can provide rapid eccentric and concentric muscle contractions. Muscle vibration is associated with a "tonic vibration reflex” that is stimulated by a sequence of rapid muscle stretching, activation of the muscle spindles and stimulation of a response that is similar to the myotatic reflex. Literature studies analyzing the acute cardiovascular responses to different exercises performed with this instrument are lacking. We investigated the acute effects of exercise with flexible poles on the heart period in healthy men.

METHOD:

The study was performed on ten young adult males between 18 and 25 years old. We evaluated the heart rate variability in the time and frequency domains. The subjects remained at rest for 10 min. After the rest period, the volunteers performed the exercises with the flexible poles. Immediately after the exercise protocol, the volunteers remained seated at rest for 30 min and their heart rate variability was analyzed.

RESULTS:

The pNN50 was reduced at 5-10 and 15-20 min after exercise compared to 25-30 min after exercise (p = 0.0019), the SDNN was increased at 25-30 min after exercise compared to at rest and 0-10 min after exercise (p = 0.0073) and the RMSSD was increased at 25-30 min after exercise compared to 5-15 min after exercise (p = 0.0043). The LF in absolute units was increased at 25-30 min after exercise compared to 5-20 min after exercise (p = 0.0184).

CONCLUSION:

A single bout of exercise with a flexible pole reduced the heart rate variability and parasympathetic recovery was observed approximately 30 min after exercise.     

Changes in renal sympathetic outflow during hypotensive haemorrhage in rats

The goal of this study was to investigate changes in renal sympathetic outflow during hypotensive haemorrhage. Normotensive Wistar-Kyoto rats were anaesthetized with chloralose (50 mg kg-1) and bled to an arterial blood pressure of 50 mmHg for 30 min. Changes in heart rate (HR) and renal nerve activity (RNA) were registered. The hypotensive haemorrhage induced a short-lasting sympathetic excitation that was followed within 5-10 min by a powerful sympathetic inhibition and bradycardia. The average maximal decrease in sympathetic activity was 65% and the maximal decrease in heart rate was 45 beats min-1. There was a close correlation between changes in heart rate and renal sympathetic activity. The marked depressor response was due at least in part to activation of vagal afferents because the depressor responses were acutely reversed by bilateral cervical vagotomy. As cardiac afferents are known to be activated by prostaglandins and bradykinins, and these agents are released by myocardial ischaemia, haemorrhage was repeated after use of indomethacin and aprotinin (a protein inhibitor decreasing bradykinin formation), and a marked sympathetic inhibition could still be elicited upon haemorrhage. We therefore suggest that the likely mechanism for activation of the vagal afferents is a squeezing of the myocardium when the heart has to contract around an almost empty chamber. In conclusion, this study demonstrated that hypotensive haemorrhage triggers profound inhibition of RNA in rats and that this sympathoinhibition is mediated primarily by mechanically sensitive cardiac vagal afferents.     

Theophylline attenuates microwave-induced impairment of memory acquisition

Numerous studies have shown that acute microwave exposure causes cognitive deficits in animals, possibly via hyperthermia, but the biological effect of microwave exposure on memory processing is still unknown. The release of adenosine is demonstrated to be a general way for the cells to respond to metabolically stressful conditions such as hypoxia and ischemia. The present study aimed to examine whether adenosine mediates biological effects of microwave exposure on memory processing using a continuous multiple-trial inhibitory avoidance task. Results demonstrated that microwave exposure for 20 min before training impaired memory acquisition and retention performance in mice, assessed by the number of training trials and by latency to enter the dark compartment. The mice exposed to microwave radiation showed a dose-dependent hyperthermia. Moreover, the cell numbers of hippocampus were decreased in the mice receiving microwave exposure at an average power density of 50 mW/cm(2), indicating the anatomical correlation to hippocampal-amygdaloid structures corresponding with the memory disrupt of the mice. Administration of theophylline, a nonspecific adenosine receptor antagonist, 30 min before microwave exposure, completely antagonized the impairment of inhibitory avoidance acquisition but not retention. These results suggest that the adenosine regulation pathway was partially involved in microwave-induced impairment of inhibitory avoidance memory.     

The assessment of cognitive function in advanced HIV-1 infection and AIDS dementia complex using a new computerised cognitive test battery.

The validity of a new computerised battery called CogState was determined in 60 individuals with advanced human immunodeficiency virus-1 (HIV-1) infection from which eleven were assessed as AIDS dementia complex (ADC) stage 1 or 2. Twenty-one seronegative individuals were recruited as controls. Participants were evaluated with a brief computerised examination, lasting 10-15 min, assessing reaction time, accuracy in working memory and learning. They were also assessed with a standard neuropsychological examination lasting 1h 30 min on average. The computerised assessment demonstrated a good sensitivity of 81.1% and specificity of 69.9% as well as good positive predictive value (81%) and acceptable construct validity (.45-.62). Slowed reaction time and learning deficits in the computerised battery were characteristic of ADC. This study supports the utility of a brief computerised battery in the detection of HIV-associated neurocognitive impairment that could be used for wide-scale screening.     

Correlation between cognitive deficits and Abeta deposits in transgenic APP+PS1 mice

Doubly transgenic mAPP+mPS1 mice (15-16 months) had impaired cognitive function in a spatial learning and memory task that combined features of a water maze and a radial arm maze. Nontransgenic mice learned a new platform location each day during 4 consecutive acquisition trials, and exhibited memory for this location in a retention trial administered 30 min later. In contrast, transgenic mice were, on average, unable to improve their performance in finding the hidden platform over trials. The cognitive performance of individual mice within the transgenic group were inversely related to the amount of Abeta deposited in the frontal cortex and hippocampus. These findings imply that mAPP+mPS1 transgenic mice develop deficits in cognitive ability as Abeta deposits increase. These data argue that radial arm water maze testing of doubly transgenic mice may be a useful behavioral endpoint in evaluating the functional consequences of potential AD therapies, especially those designed to reduce Abeta load.     

Effects of glucose and 2-deoxyglucose on memory formation in the chick: interaction with beta(3)-adrenoceptor agonists

Consolidation of a weakly reinforced memory that would otherwise fade after 30 min can be achieved by central or peripheral injection of the selective beta(3)-adrenoceptor agonist CL316243 as well as the beta(2)-adrenoceptor agonist zinterol and the alpha(1)-adrenoceptor antagonist prazosin in the day-old chick. The effect of the beta(3)-adrenoceptor agonist is mimicked by peripheral or central injection of glucose that is effective in enhancing memory from 25 min before to 25 min after training. Glucose uptake into various cell types has been described following activation of beta(3)-adrenoceptors and in this paper we demonstrate that activation of beta(3)-adrenoceptors by CL316243 facilitates the effect of a dose of glucose that does not normally enhance memory, whereas a beta(2)-adrenoceptor agonist and an alpha(1)-adrenoceptor antagonist have no effect. Administration of the glucose uptake inhibitor 2-deoxyglucose prevented the consolidation of strongly reinforced training. The beta(3)-adrenoceptor agonist facilitated the effect of a non-amnestic dose of 2-deoxyglucose to inhibit memory. There are two time periods relative to the learning trial where memory is vulnerable to interference by centrally administered 2-deoxyglucose: one related to short-term memory and one at the time of consolidation into long-term memory. Peripheral injection of 2-deoxyglucose is only effective at the time of consolidation. The action of the beta(3)-adrenoceptor agonist to facilitate the action of 2-deoxyglucose only occurs at the time of consolidation. We suggest that a noradrenergic agonist acting at beta(3)-adrenoceptors enhances memory formation by facilitation of glucose uptake at the time of memory consolidation. This may represent a novel mechanism that would be beneficial for developing compounds for the facilitation of memory in diseases with cognitive deficits.     

Cognitive function following treadmill exercise in thermal protective clothing

Occupational injuries are common among firefighters who perform strenuous physical exertion in extreme heat. The thermal protective clothing (TPC) worn by firefighters inhibits normal thermoregulation, placing the firefighter at risk of hypohydration and hyperthermia that may result in cognitive decline. We tested whether cognitive function changes after treadmill exercise in TPC. In an initial study (Cog 1), ten healthy volunteers performed up to 50 min of treadmill exercise while wearing TPC in a heated room. A battery of neurocognitive tests evaluating short-term memory, sustained and divided attention, and reaction time was administered immediately before and after exercise. In a follow-up study (Cog 2), 19 healthy volunteers performed a similar exercise protocol with the battery of cognitive tests administered pre-exercise, immediately post-exercise, and serially up to 120 min after exercise. Subjects performed 46.4 ± 4.6 and 48.1 ± 3.6 min of exercise in the Cog 1 and Cog 2, respectively. In both studies heart rate approached age predicted maximum, body mass was reduced 1.0–1.5 kg, and body core temperature increased to levels similar to what is seen after fire suppression. Neurocognitive test scores did not change immediately after exercise. Recall on a memory test was reduced 60 and 120 min after exercise. The mean of the 10 slowest reaction times increased in the 120 min after exercise. Fifty minutes of treadmill exercise in TPC resulted in near maximal physiologic strain but alterations in neurocognitive performance were not noted until an hour or more following exercise in TPC.     

基于氢质子磁共振波谱技术研究L波段微波辐射对大鼠学习和记忆的影响

目的:基于氢质子磁共振波谱（1H-MRS）技术,分析L波段微波辐射对大鼠学习和记忆功能的影响。方法:SPF级雄性Wistar大鼠26只,随机分为假辐射组（Sham组）、L波段30 mW/cm2微波辐射组（L30组）。将L30组大鼠放置于有机玻璃照射盒中,使用L波段微波辐射源从背侧照射10 min;Sham组大鼠除未行微波辐射外其他处理与照射组相同。采用Morris水迷宫方法于辐射后1 d和7 d对各组大鼠的学习和记忆功能进行检测。使用1H-MRS于辐射后1 d和7 d检测鼠脑中的N-乙酰天门冬氨酸（N-acetylaspartate, NAA）、胆碱（Choline, Cho）、肌酸（Creatine, Cr）水平。结果:微波辐射后1 d和7 d,与Sham组相比,L30组平均逃避潜伏期有延长趋势,但无统计学意义（P>0.05）。1H-MRS检测结果显示辐射后1 d,与Sham组比较,L30组1H-MRS波谱NAA/Cr值显著降低（P<0.05）,Cho/Cr值无显著差异（P>0.05）;辐射后7 d,与Sham组比较,L30组大鼠脑部NAA/Cr和Cho/Cr值均无显著差异（P>0.05）。结论:30 mW/cm2 L波段微波辐射后1 d大鼠脑内NAA/Cr显著降低,而学习和记忆行为学指标无显著改变,提示利用1H-MRS技术能够在被试未出现显著行为学改变时检测出微波辐射对学习和记忆相关神经元的影响。     

Temporary amnesia induced by cold anesthesia and hypoxia in Drosophila

Memory consolidation in Drosophila was investigated using cold anesthesia- and hypoxia-induced amnesia. Individual flies were operantly trained to avoid the specific flight orientations with respect to the landmarks surrounding them when paired with heat reinforcement at a flight simulator. Cold anesthesia, introduced immediately after training, exerted a significantly diminishing effect on memory between 15 and 150 min after training. Hypoxia delivered immediately after training had a significantly diminishing effect on memory between 30 and 150 min after training. In addition, cold anesthesia disrupted memory only when introduced within the first 20 min, while hypoxia worked only when delivered within the first 2 min after training. When interpreted in the context of a four-phase model of memory consolidation, the results suggest that 1) cold anesthesia disrupts both short-term memory (STM) and anesthesia-resistant memory (ARM), 2) hypoxia disrupts ARM specifically, 3) both of them leave long-term memory (LTM) intact, and 4) LTM may be independent of availability of STM and ARM in flies.