Decoding rule from vasoconstrictor skin sympathetic nerve activity to nonglabrous skin blood flow in humans at normothermic rest

Although an importance of vasoconstrictor skin sympathetic nerve activity (SNA) in control of cutaneous circulation is widely recognized, the decoding rule that translate dynamic fluctuations of vasoconstrictor skin SNA into skin blood flow is not fully understood. In 10 male subjects who rested in supine position under normothermic condition, we measured skin blood flow index (by laser-Doppler flowmetry) at the dorsum pedis, and vasoconstrictor skin SNA (by microneurography) that was confirmed to innervate the same region as the flow index. We determined the transfer and coherence functions from the neural activity input to the flow and quantified the contribution and predictability from the input to output by system engineering technique. The results showed that in frequency-domain analysis, the transfer function from vasoconstrictor skin SNA to skin blood flow had low-pass filter characteristics with 3.6 ± 0.1 s of pure time delay. The coherence function was approximately 0.5 between 0.01 and 0.1 Hz and less above 0.1 Hz. In time-domain analysis, the predictability from the SNA to the skin blood flow was approximately 50%. These findings indicate that at normothermic rest, the decoding rule from vasoconstrictor skin SNA to skin blood flow of skin is characterized by low-pass filter with 3–4 s of pure time delay, and that the vasoconstrictor skin SNA contributes to a half of fluctuation of skin blood flow in the condition. The incomplete dependence of skin blood flow on vasoconstrictor skin SNA may confirm nonneural mechanisms to control cutaneous circulation even at normothermic rest.     

Effect of aging on heart rate and blood pressure variabilities in healthy men and women

OBJECT: To clarify the effect of aging and gender on heart rate and blood pressure variability in healthy men and women. SUBJECT AND METHODS: One hundred ninety four healthy subjects aged from 20 to 70(97 men and 97 women) were examined. Heart beat and blood pressure during 5 minutes in the supine and standing positions were measured under a respiration rate of 15/min. Blood pressure and heart were measured with Finapres and Biotop, respectively. Data entry and spectral analysis were carried out by the Fast Fourier Transform(FFT) method with BIMUTAS-II, after correcting 256 data with Hanning window function and resampling at 200 Hz. RESULT AND DISCUSSION: High frequency power(HF: 0.15-0.50 Hz) of heart rate variability decreased with age in both men and women, Low frequency power (LF: 0.05-0.15 Hz) of systolic blood pressure(SBP) variability in the standing posture decreased with age in men. The HF of SBP variability in the standing posture was decreased with age in both men and women. These findings suggest that aging and gender affected heart rate and blood pressure variability.     

Coordination of the EEG and the heart rate of preterm neonates during quiet sleep

Aim of this study was to confirm that EEG bursts are associated with heart rate (HR) accelerations, and to investigate the synchronicity between quadratic phase couplings (QPC) courses of the EEG and HR before and during burst activity during quiet sleep in preterm newborns. The time-courses of QPC between frequency components of the EEG ([0.25–1.0 Hz] ↔ [4.0–6.0 Hz]) as well as between the Mayer–Traube–Hering (MTH) wave and the frequency component of the HR associated to the respiratory sinus arrhythmia (RSA) ([0.02–0.15 Hz] ↔ [0.4–1.5 Hz]) were investigated in five preterm neonates. During quiet sleep, the EEG alternates between burst and interburst activity. The burst onsets were used to trigger an averaging procedure for the EEG, HR, and QPC courses. It can be demonstrated that the envelopes of the EEG rise after the burst onset accompanied by an acceleration of HR before or at the burst maximum. The QPC courses show that the HR's QPC increases before or at the burst onset whereas the increase of the EEG's QPC is delayed. The synchronous changes of EEG and HR as well as of the corresponding QPC courses indicate a coupling between cortical, thalamocortical and neurovegetative brain structures. Such a coupling might be mediated by the MTH waves in the blood pressure.     

用联合熵分析短时心率变异信号的非线性动力学复杂性

用联合熵方法来分析短时心率变异性信号,该方法可以有效地从短时心跳间期信号中提取出动力学信息,从而反映心率变异性的强弱,为临床应用提供了方便。我们首先介绍联合熵基本理论,用低维的混沌序列进行了检验,证明该方法有效。然后将其应用于人体短时的心跳间期时间序列,该方法可以揭示复杂生理信号所具有的动力学特征以及衰老和疾病所伴随的非线性动力学复杂性的丢失和降低的个体自适应能力。最后,用联合熵方法来考察短时心率变异性信号的非随机性程度,该方法可以有效的揭示心室对心室纤维性颤动响应的非随机模式。     

Circulation in the lungs and microcirculation in the alveoli

Human lungs weighing ca 600 g permit the passage of 5–6 l of blood per minute. The blood capacity of the human lungs is about 0.5 l. Consequently, each 0.5 l of blood is during 5 s. The questions arise of how such a large mass of blood passes through such a small mass of lungs and what the reasons are for such a high rate of blood oxygenation. Since the structure of lungs in mammals is almost the same, we tried to solve these issues studying the rats, in which 20–22 ml of blood pass through the lungs of 1.5–2.0 g mass. A great blood flow appeared to be associated with a large diameter of the lung arterioles and a high rate of the blood flow in them. The high rate of oxygenation is accounted for by a special structure of alveoli and special conditions of the blood flow, which create ideal conditions for oxygen diffusion.     

Immunization against angiotensins for the treatment of hypertension

Current vaccination approaches against hypertension target angiotensin I and angiotensin II, key components of the renin–angiotensin system. The effectiveness and long-term safety of blockade of the renin–angiotensin system with antihypertensive small-molecule drugs is well documented. Phase I/II testing of the angiotensin I vaccine PMD3117 demonstrated safety and immunogenicity in humans. While angiotensin I-specific antibodies were induced blood pressure was not lowered, presumably due to insufficient antibody levels. A second vaccine, which targets angiotensin II, has been clinically tested. Administration of CYT006-AngQb to subjects with mild to moderate hypertension was safe and well tolerated. After three administrations of 300 μg of the vaccine, ambulatory blood pressure was significantly reduced compared to placebo. The vaccine was particularly effective early in the morning as systolic and diastolic blood pressure were lowered by − 25 mm Hg and − 13 mm Hg, respectively. Further studies are required to show long-term safety and to assess how robust and long-lived the blood pressure reduction is. It will also be important to ascertain whether the strong reduction of blood pressure in the early morning, when most cardiovascular events occur, might result in long-term benefits over current therapies.     

Heart rate dynamics during acute pain in newborns

Autonomic nervous system modulation of heart rate is significantly altered during painful procedures in newborns. Most studies investigating pain employed only linear-based analysis methods, thus ignoring the complex, non-linear nature of heart rate control mechanisms. The emergences of dynamic, nonlinear analysis methods enable us to uncover information embedded in the fluctuations of heart rate not otherwise noticeable. Our objective was to examine how cardiac dynamics change in newborns who undergo heel lancing by analyzing linear and nonlinear characteristics of heart rate fluctuations. We used dynamic nonlinear analyses methods to reveal heart rate variability and complexity alterations during painful stimulus in newborns. Poincaré plots were applied to examine the dynamics of the system, sample entropy to investigate the complexity of the system, and detrended fluctuation analysis, to reveal the fractal properties of the system. Heart rate significantly increased (165 vs.123 beats per minute, p?<?0.001) while variability decreased. Sample entropy and the quantitative measures of the Poincaré plots (SD1 and SD2) significantly decreased during heel lancing (0.75 vs. 1.0, p?<?0.01; 6.4 vs. 12.8, p?<?0.001; and 30.4 vs. 50.5, p?<?0.01, respectively). Detrended fluctuation analysis showed a significant decrease in the short-term scaling exponent ??1 (1.06 vs. 1.3, p?<?0.001), and an increase in the long-term scaling exponent ??2 (1.5 vs. 1.1, p?<?0.001). Our results indicate altered complexity of heart rate variability during painful stimulus in newborns and disruption of the mechanisms that regularly control it. Such alterations resemble certain pathological conditions and may represent stress reaction.     

Conditioned diastolic blood pressure

Four groups of normotensive subjects were used in an experiment designed to: (a) replicate earlier data, (b) determine whether heart rate and respiration rate changes accompanied the development of acquired bi-directional diastolic blood pressure responses, and (c) investigate whether males and females acquired diastolic blood pressure responses at differential rates. Observations were carried out over one baseline and eight consecutive one-hour training sessions. Analyses of the blood pressure scores revealed subjects were able to acquire a bi-directional response, thereby confirming earlier reports. From subsequent analysis of the heart rate and respiration rate scores and from intercorrelations between diastolic blood pressure, heart rate, and respiration rate, no consistent relationships or patterns emerged. Comparisons of male and female blood pressure performance failed to yield evidence of reliable sex differences.     

Short-time lower leg ischemia reduces plantar foot sensitivity

The aim of this study was to investigate the effects of short-time blood flow occlusion on plantar foot vibration sensitivity of healthy young adults. 39 subjects (20 female; 19 male) participated in the study. Blood flow reduction was evoked with a pneumatic tourniquet, placed about 10 cm above the popliteus cavity. Vibration thresholds (200 Hz) were measured at three anatomical locations of the plantar foot (heel, first metatarsal head and hallux) in three different cuff pressure conditions: baseline (0 mmHg), low (50 mmHg) and high (150 mmHg). Each pressure condition was held for 4 min prior to vibration threshold measurements. No reperfusion time was allowed between conditions. The results show a significant increase in vibration thresholds measured at all anatomical locations in the high pressure condition (150 mmHg), whereas low pressure (50 mmHg) caused a significant threshold increase only at the hallux, compared to baseline (0 mmHg) measurements. Short-time blood flow occlusion seems to affect the afferent transmission of vibration stimuli from Vater–Pacini corpuscles, resulting in decreased plantar foot sensitivity. The present study provides an insight into initial adaptations caused by reduced blood flow in plantar foot sensitivity of healthy young adults.     

Nonlinear Analysis of Physiological Time Series

The heart rate variability could be explained by a low-dimensional governing mechanism. There has been increasing interest in verifying and understanding the coupling between the respiration and the heart rate. In this paper we use the nonlinear detection method to detect the nonlinear deterministic component in the physiological time series by a single variable series and two variables series respectively, and use the conditional information entropy to analyze the correlation between the heart rate, the respiration and the blood oxygen concentration. The conclusions are that there is the nonlinear deterministic component in the heart rate data and respiration data, and the heart rate and the respiration are two variables originating from the same underlying dynamics.     

Loss of otolith function with age is associated with increased postural sway measures

Loss of balance and increased fall risk is a common problem associated with aging. Changes in vestibular function occur with aging but the contribution of reduced vestibular otolith function to fall risk remains unknown. We examined a population of 151 healthy individuals (aged 21–93) for both balance (sway measures) and ocular counter-rolling (OCR) function. We assessed balance function with eyes open and closed on a firm surface, eyes open and closed on a foam surface and OCR during ±20 degree roll tilt at 0.005 Hz. Subjects demonstrated a significant age-related reduction in OCR and increase in postural sway. The effect of age on OCR was greater in females than males. The reduction in OCR was strongly correlated with the mediolateral measures of sway with eyes closed. This correlation was also present in the elderly group alone, suggesting that aging alone does not account for this effect. OCR decreased linearly with age and at a greater rate in females than males. This loss of vestibular otolith-ocular function is associated with increased mediolateral measures of sway which have been shown to be related to increased risk of falls. These data suggest a role for loss of otolith function in contributing to fall risk in the elderly. Further prospective, longitudinal studies are necessary to confirm these findings.     

恶性腹水源性腹腔间隔室综合征行早期腹腔减压治疗中患者心率、血压和呼吸变化规律的临床观察

目的 探讨恶性腹水源性腹腔间隔室综合征(MAACS)行早期置管减压治疗过程中,腹水引流量与心率、血压、呼吸变化的关系。方法 采用回顾性横断面调查,分析2012年6月—2017年6月山西大同大学附属医院肿瘤外科22例MAACS患者的临床资料。其中男13例、女9例,年龄45～74(56.44±4.46)岁。肝癌6例,胃癌2例,结肠癌1例,直肠癌2例,胰腺癌1例,胆管癌1例,卵巢癌6例,宫颈癌2例,癌性腹水未找到原发灶1例;其中合并腹腔内转移癌6例。患者均行早期腹腔减压治疗,在腹腔引流减压过程中,测量记录腹水引流前、每引流500 mL及引流完毕时腹腔压力,并同步监测患者心率、血压、呼吸的变化情况,采用简单线性回归分析腹腔引流量与心率、血压、呼吸的相关性。结果 22例患者均顺利完成腹腔置管减压治疗,腹水减压引流时间3~6(4.32±0.54)h。引流腹水量4 000～6 900(5 260±610)mL。在腹腔引流减压过程中,与腹水引流前比较:引流量≥1 500 mL时,腹腔压力下降、呼吸次数减少,差异均有统计学意义(P值均＜0.05);从流量≥1 000 mL时,各观察点心率下降,差异均有统计学意义(P值均＜0.05)。简单线性回归分析显示,随着腹腔引流量的逐渐增加,腹腔引流量与心率、呼吸有相关性(r=0.952、0.888, P值均＜0.05)。线性回归分析得回归方程为:＾Y_心率=-0.004 57 X_{腹腔引流量(mL)} + 119.0,＾Y_呼吸=-0.003 43 X_{腹腔引流量(mL)} +35.8。减压治疗后24 h内,19例心率、血压、呼吸平稳;3例出现血压下降,心率再次增加,其中2例经补液升压治疗血压、心率恢复正常,1例放弃治疗死亡。结论 早期置管减压治疗MAACS是安全的,随着腹腔引流量的增加,心率、呼吸逐渐下降,血压维持平稳,在减压后24 h内仍需密切观察心率、呼吸、血压变化情况。     

The role of affect and rumination in cardiovascular recovery from stress

This study examined the psychological processes that may impede or facilitate cardiovascular recovery. It was hypothesized that cardiovascular recovery would be hampered by negative affect and rumination, and facilitated by positive affect. In an experimental study, stress was elicited by exposing participants (N = 110) to a mental arithmetic task with harassment. After the stress task, affective levels were manipulated via a movie scene with negative, neutral, or positive emotional valence, or without an affect manipulation (control condition). During the entire experiment, heart rate and systolic and diastolic blood pressure levels were measured continuously. Results indicated that blood pressure recovery was hampered by the negative affect manipulation and by rumination. However, the positive affect manipulation did not facilitate blood pressure recovery. No effects were found on heart rate recovery. In sum, the findings emphasize the importance of negative affect and rumination in stress recovery.     

运用排列熵方法分析冥想训练对心率变异性的影响

背景：冥想训练有利于保持身体与心理健康,训练过程中通过自主神经调整训练心率是一个可能的因素。两者之间关系的研究有助于加深对于心血管系统调节以及健康训练的理解。 目的：从复杂性分析的角度考察冥想训练过程中心率调整的规律。 方法：心率变异信号取自PhysioNet中冥想训练心率数据库,应用排列熵方法对中国气功以及瑜伽训练前和训练中数据分别进行分析,考察两种训练对于心率复杂性的影响。 结果与结论：冥想训练中心率变异序列的排列熵值均显著小于训练前的熵值,表明中国气功以及瑜伽均有降低心率复杂性的效果。而前期研究使用排列熵对于年轻、年老、心力衰竭患者的研究表明衰老和疾病会使排列熵值增加。因此,冥想训练通过自主神经对心率的调整可能是其帮助人体保持健康的一个重要因素。     

Percutaneous excretion of iron and ferritin (through Al-hijamah) as a novel treatment for iron overload in beta-thalassemia major,hemochromatosis and sideroblastic anemia

Iron overload is a big challenge when treating thalassemia (TM), hemochromatosis and sideroblastic anemia. It persists even after cure of TM with bone marrow transplantation. Iron overload results from increased iron absorption and repeated blood transfusions causing increased iron in plasma and interstitial fluids. Iron deposition in tissues e.g. heart, liver, endocrine glands and others leads to tissue damage and organ dysfunction. Iron chelation therapy and phlebotomy for iron overload have treatment difficulties, side effects and contraindications. As mean iron level in skin of TM patients increases by more than 200%, percutaneous iron excretion may be beneficial. Wet cupping therapy (WCT) is a simple, safe and economic treatment. WCT is a familiar treatment modality in some European countries and in Chinese hospitals in treating different diseases. WCT was reported to clear both blood plasma and interstitial spaces from causative pathological substances (CPS). Standard WCT method is Al-hijamah (cupping, puncturing and cupping, CPC) method of WCT that was reported to clear blood and interstitial fluids better than the traditional WCT (puncturing and cupping method, PC method of WCT). In other word, traditional WCT may be described as scarification and suction method (double S technique), while Al-hijamah may be described as suction, scarification and suction method (triple S technique). Al-hijamah is a more comprehensive treatment modality that includes all steps and therapeutic benefits of traditional dry cupping therapy and WCT altogether according to the evidence-based Taibah mechanism (Taibah theory). During the first cupping step of Al-hijamah, a fluid mixture is collected inside skin uplifting due to the effect of negative pressure inside sucking cups. This fluid mixture contains collected interstitial fluids with CPS (iron, ferritin and hemolyzed RBCs in thalassemia), filtered fluids (from blood capillaries) with iron and hemolyzed blood cells (hemolyzed RBCs, WBCs and platelets). That fluid mixture does not contain intact blood cells (having diameters in microns) that are too big to pass through pores of skin capillaries (6–12 nm in diameter) and cannot be filtered. Puncturing skin upliftings and applying second cupping step excrete collected fluids. Skin scarifications (shartat mihjam in Arabic) should be small, superficial (0.1 mm in depth), short (1–2 mm in length), multiple, evenly distributed and confined to skin upliftings. Sucking pressure inside cups (−150 to −420 mmHg) applied to skin is transmitted to around skin capillaries to be added to capillary hydrostatic pressure (−33 mmHg at arterial end of capillaries and −13 mmHg at venous end of capillaries) against capillary osmotic pressure (+20 mmHg). This creates a pressure gradient and a traction force across skin and capillaries and increases filtration at arterial end of capillaries at net pressure of −163 to −433 mmHg and at venous end of capillaries at net pressure of −143 to −413 mmHg resulting in clearance of blood from CPS (iron, ferritin and hemolyzed blood cells). Net filtration pressure at renal glomeruli is 10 mmHg i.e. Al-hijamah exerts a more pressure-dependent filtration than renal glomeruli. Al-hijamah may benefit patients through inducing negative iron balance. Interestingly, Al-hijamah was reported to decrease serum ferritin significantly (by about 22%) in healthy subjects while excessive traditional WCT was reported to cause iron deficiency anemia. Al-hijamah is a highly recommended treatment in prophetic medicine. In conclusion, Al-hijamah may be a promising adjuvant treatment for iron overload in TM, hemochromatosis and sideroblastic anemia.     

Respiratory responses to somatostatin microinjections into the Bötzinger complex and the pre-Bötzinger complex of the rabbit

The respiratory responses to bilateral microinjections (30–50 nl) of 5 mM somatostatin (SOM) or 10 mM cyclosomatostatin (c-SOM, a SOM antagonist) into the Bötzinger complex (BötC), the pre-Bötzinger complex (preBötC) and the rostral inspiratory portion of the ventral respiratory group (iVRG) were investigated in urethane–chloralose anesthetized, vagotomized, paralysed and artificially ventilated rabbits. SOM microinjections into the BötC decreased respiratory frequency and the rate of rise of phrenic nerve activity without obvious changes in its peak amplitude. SOM microinjected into the preBötC caused increases in respiratory frequency and decreases in peak phrenic activity associated with increases in its rate of rise. No changes in respiration were induced by SOM microinjections into the iVRG. Microinjections of c-SOM into the preBötC caused decreases in respiratory frequency as well as in peak amplitude and rate of rise of phrenic nerve activity. The results show that endogenously released SOM within the preBötC contributes to shape the pattern of baseline respiratory activity and that SOM receptors within the BötC and the preBötC have a role in the modulation of respiration in the rabbit.     

Coupling and Irregularity in the aging motor system: Tremor and movement

This experiment examined the hypothesis that aging reduces the coupling between system components, resulting in a loss of complexity in behavior. Young (18–23 years), old (60–65 years), and older old (70–75 years) subjects performed rhythmical movement and postural tasks with the index finger. Irregularity of the acceleration dynamics was lower during postural tremor and movement in the old and older old subjects, an age effect that was only observed on the mediolateral axis of motion. Coupling across the axes of motion was significantly higher during rhythmic movement in the elderly but remained unaltered across the tasks in the young adults. The results show that the loss of complexity with aging can be detected even in healthy 60–65-year-olds, but demonstrates the need for postural tremor to be examined on more than a single axis of motion. Our findings suggest that reduced motor adaptability with aging results from a greater demand on task-related reorganization of the motor output.     

Isometric strength,endurance, and the blood pressure and heart rate responses during isometric exercise in healthy men and women,with special reference to age and body fat content

The relationship of sex, age, and body fat content were assessed on the maximal voluntary strength (MVC), the endurance of a sustained contraction held at 40% of the subject's maximal strength, and the associated changes in blood pressure and heart rate. Isometric hand-grip strength was, as expected, greater in men than in women; however, in both sexes, age was inversely related to isometric strength, particularly in women. Body fat content, however, was directly related to strength. In contrast, in both male and female subjects aging was directly related to isometric endurance while body fat content was now inversely related to isometric endurance. The increase in heart rate throughout a fatiguing contraction at 40% MVC was strikingly similar in men and women. Heart rate, which always increased during exercise, attained its highest magnitude during exercise in the subjects who had the highest resting heart rates. However, older subjects displayed a smaller increase in exercising heart rates than younger subjects. The blood pressure at the end of the 40% MVC was directly related to the resting blood pressure. However, aging and body fat content both increased the resting systolic blood pressure in men and women; this aging effect was further exaggerated during the exercise.     

Exploring non-invasive methods to assess pain in sheep

The aim of this study was to determine whether changes in eye temperature, measured using infrared thermography (IRT), and heart rate variability (HRV) can detect moderate levels of pain in sheep. Six ewes received the following treatments: 1) noxious ischaemic stimulus by application of a forelimb tourniquet (S), 2) noxious ischaemic stimulus and flunixin meglumine (S + F), and 3) flunixin meglumine (F). Maximum eye temperature, HRV, mechanical nociceptive threshold, blood pressure and behaviour were recorded for up to 60 min, including 15 min of baseline, 30 min during intervention and 15 min post-intervention. There was a tendency towards a decrease in the heart rate variability parameters RMSSD (the root mean square of successive R-R intervals) and SDNN (the standard deviation of all interbeat intervals) in treatment S compared to treatment F, and a significant increase in the same parameters between test day 1 and 3. A reduction in eye temperature was detected for all treatments during intervention, but no difference was found between S and F and S + N and F during intervention. The eye temperature decreased more in test day 2 and 3 compared to test day 1 during intervention. A significant reduction for both lip licking and vocalisation was observed between test day 1 and 3, and forward facing ears was the ear posture most frequently recorded in test day 1. We suggest that HRV is a sensitive, non-invasive method to assess mild to moderate pain in sheep, whereas IRT is a less sensitive method.     

Nonlinear Coupling Among Heart Rate,Blood Pressure,and Respiration in Patients Susceptible to Neuromediated Syncope

The aim of this study is to evaluate the degree of coupling between the cardiovascular variability series and the respiration in subjects susceptible to neurally mediated syncope. Twenty-one informed patients susceptible to syncope and ten sex- and age-matched control subjects were enrolled in the study. ECG, respiration activity, and arterial blood pressure were simultaneously recorded at rest (controlled and free breathing) and during the 70° head-up TILT test (free breathing). The degree of nonlinear coupling among heart rate variability (HRV), blood pressure variability (BPV), and respiration was quantified by means of two indices according to a multivariate embedding-based approach. Eleven patients developed syncope during the TILT test. We found that during the late TILT phase, the TILT-positive group experienced a significant increase in nonlinear coupling respect to the mid TILT phase (p < 0.01, Wilcoxon nonparametric test for pair data) while the TILT-negative group did not (p < 0.01, Mann-Whitney U-test). If the proposed nonlinear coupling indexes can be considered expression of the coupling mechanisms involved in the vagal regulation of the cardiovascular system, an increase in vagal tone accompanied by a decrease in sympathetic activity seem to occur before a vasovagal event. © 2003 Biomedical Engineering Society. PAC2003: 8719Hh, 8719Uv, 8719La