Circulating autoantibodies in patients with aspirin-intolerant asthma: an epiphenomenon related to airway inflammation

Several studies have suggested the involvement of an autoimmune mechanism in aspirin (ASA)-intolerant asthma. To test this hypothesis, we measured the levels of circulating autoantibodies, such as IgG and IgA to tissue transglutaminase (TGase), IgG to cytokeratins (CKs) 8, 18, and 19, Clq-binding immune complex (CIC), and antinuclear antibody (ANA), in the sera of 79 patients with ASA-intolerant asthma (Group I) and those of two control groups, consisting of 61 patients with ASA-tolerant asthma (Group II) and 88 healthy control subjects (Group III) by means of ELISA. Significantly higher prevalences of IgG antibodies to CK18 (13.9%) and CK19 (17.7%) were noted in Group I, as compared with Group III (p<0.05 for all) not with Group II. Regarding the prevalences of other autoantibodies, the levels of ANA (1.3%), IgG to TGase (3.8%), and CIC (24.7%) in Group I were not significantly different from those in Groups II and III. Significant correlations were found between positivities for the anti-CK18 and anti-CK19 autoantibodies and the PC(20) methacholine values in the analysis of asthma Groups I and II vs. normal controls, (p=0.001 and p=0.003, respectively). Further studies are needed to explore the potential involvement of an autoantibody-mediated mechanism in the clinical manifestation of bronchial asthma.     

Enhanced severity of virus associated lower respiratory tract disease in asthma patients may not be associated with delayed viral clearance and increased viral load in the upper respiratory tract.

BACKGROUND: Viral respiratory infections, particularly human rhinovirus (HRV) infections, are the most common cause of asthma exacerbation. HRV infections usually lead to more severe and longer duration of lower respiratory tract (LRT) symptoms in asthmatics than in otherwise healthy individuals. However, the exact mechanism by which viruses contribute to exacerbation of asthma is unknown. OBJECTIVES: The main objective of our study was to investigate the relationship of the enhanced severity of LRT symptoms to viral dynamics or cytokine responses in the upper respiratory tract (URT). STUDY DESIGN: Therefore, we conducted a longitudinal study in which asthmatics and healthy controls were followed during natural viral respiratory tract infections. RESULTS: Our study confirmed that viral respiratory tract infections caused more severe problems of the LRT in asthma patients as compared to healthy controls. However, for all subjects, the severity of LRT symptoms were not related to viral load or prolonged viral shedding in the URT. In addition, we did not detect differences in proinflammatory cytokines in the URT between asthmatics and controls. CONCLUSION: Persistence of the virus, as well as viral load in the URT, may not be associated with the induction and/or persistence of asthmatic symptoms.     

Serum eosinophil cationic protein (sECP) in subjects with a history of asthma symptoms with or without rhinitis.

BACKGROUND: Serum eosinophil cationic protein (sECP) has been proposed as a marker of disease activity in bronchial asthma. The study aimed to evaluate the role of sECP in screening asthmatics in a group of subjects with asthma and rhinitis symptoms, and the relationship between sECP and clinical and functional parameters of asthma. METHODS: A total of 185 subjects with asthma symptoms, 149 of them with rhinitis as well, underwent skin tests, spirometry, methacholine (MCH) test, blood sampling for eosinophil percentage (bEOS%) and sECP determination, and nasal secretions smear for eosinophil percentage (nEOS%) determination; PEF values, symptoms, and medication over a period of 4 weeks after sampling for sECP quantitation were recorded on a diary. RESULTS: A total of 99 (53%) subjects received a diagnosis of asthma (asthmatics), and 86 did not (nonasthmatics). In asthmatics, neither sECP nor bEOS% was significantly different from nonasthmatics. In asthmatics, sECP was higher in subjects with increased than in those with normal daily PEF variability (16.4, 6.8-24.4 vs 5.3, 3.9-8.4 microg/l; P<0.001). sECP was higher in moderate persistent asthma than in intermittent asthma (24.8, 10.6-53 vs 8.4, 5.6-14.1; P<0.05). In nonasthmatics (73 with a history of rhinitis), both sECP and bEOS% correlated with nEOS% (rho=0.35; P<0.01 and rho=0.53; P<0.001). CONCLUSIONS: In adults with asthma symptoms with or without rhinitis, sECP did not distinguish asthmatics from nonasthmatics. In asthmatics, sECP was associated with PEF variability and symptom severity. In subjects with asthma and rhinitis, as well as in subjects with only rhinitis, sECP levels are possibly influenced by nasal inflammation.     

Effects of static contraction and cold stimulation on cardiovascular autonomic indices, trapezius blood flow and muscle activity in chronic neck�Cshoulder pain

The aim of the present study was to investigate reactions in trapezius muscle blood flow (MBF), muscle activity, heart rate variability (HRV) and systemic blood pressure (BP) to autonomic tests in subjects with chronic neck-shoulder pain and healthy controls. Changes in muscle activity and blood flow due to stress and unfavourable muscle loads are known underlying factors of work-related muscle pain. Aberration of the autonomic nervous system (ANS) is considered a possible mechanism. In the present study, participants (n?=?23 Pain, n?=?22 Control) performed autonomic tests which included a resting condition, static hand grip test (HGT) at 30% of maximal voluntary contraction, a cold pressor test (CPT) and a deep breathing test (DBT). HRV was analysed in time and frequency domains. MBF and muscle activity were recorded from the upper trapezius muscles using photoplethysmography and electromyography (EMG). The pain group showed reduced low frequency-HRV (LF) and SDNN during rest, as well as a blunted BP response and increased LF-HRV during HGT (?systolic 22?mm Hg; ?LF(nu) 27%) compared with controls (?systolic 27; ?LF(nu) 6%). Locally, the pain group had attenuated trapezius MBF in response to HGT (Pain 122% Control 140%) with elevated trapezius EMG following HGT and during CPT. In conclusion, only HGT showed differences between groups in systemic BP and HRV and alterations in local trapezius MBF and EMG in the pain group. Findings support the hypothesis of ANS involvement at systemic and local levels in chronic neck-shoulder pain.     

Nonlinear analysis of heart rate variability of healthy subjects and patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is one of the causes of mortality worldwide with an increasing prevalence. Heart rate variability (HRV) reflects the regulation mechanism of the cardiac activity by the autonomic nervous system. The assessment of HRV by using nonlinear methods is more sensitive for the detection of complexity when compared to linear methods. This study aims to get information about the autonomic dysfunction occurred in patients with COPD by analysing the complexity of HRV. Electrocardiogram signals recorded from healthy subjects, patients with moderate COPD and severe COPD (eight subjects per group) were analysed. The HRV signals were acquired from ECG signals. Signals were reconstructed in the phase space and largest Lyapunov exponent (LLE), correlation dimension, Hurst exponent and approximate entropy (ApEn) values were calculated. It has seen that for the patients with COPD LLE, correlation dimension, Hurst exponent and ApEn values were less than control group. According to this, HRV complexity decreases in the presence of COPD. However, there is no significant difference between COPD groups and the severity of COPD has no effect on the chaoticity of the system. The results revealed that autonomic dysfunction occurred in patients with COPD is associated with reduced HRV complexity.     

Radial basis function neural networks for the characterization of heart rate variability dynamics

This study introduces new neural network based methods for the assessment of the dynamics of the heart rate variability (HRV) signal. The heart rate regulation is assessed as a dynamical system operating in chaotic regimes. Radial-basis function (RBF) networks are applied as a tool for learning and predicting the HRV dynamics. HRV signals are analyzed from normal subjects before and after pharmacological autonomic nervous system (ANS) blockade and from diabetic patients with dysfunctional ANS. The heart rate of normal subjects presents notable predictability. The prediction error is minimized, in fewer degrees of freedom, in the case of diabetic patients. However, for the case of pharmacological ANS blockade, although correlation dimension approaches indicate significant reduction in complexity, the RBF networks fail to reconstruct adequately the underlying dynamics. The transient attributes of the HRV dynamics under the pharmacological disturbance is elucidated as the explanation for the prediction inability.     

Heart rate variability and its determinants in patients with severe or mild essential hypertension.

How cardiac autonomic nervous control is related to the severity of essential hypertension in patients receiving long-term antihypertensive therapy is not well known. The aim of this study was to examine heart rate variability (HRV), a non-invasive measure of cardiac autonomic function, in patients with long-term and medically treated mild and severe essential hypertension and healthy control subjects, and to assess the clinical determinants of HRV in these patients. Thirty-four patients with severe essential hypertension (SEHT) and 29 with mild essential hypertension (MEHT) as well as healthy age- and sex-matched control subjects were studied. HRV was assessed from 10 min ECG-recordings during paced (0.2 Hz) breathing at rest and expressed as time and frequency domain measures. In the SEHT group time (SDNN, RMSSD) and frequency domain measures (total power, low-frequency (LF) power and high-frequency (HF) power of HRV in absolute units, and LF and HF power of HRV in normalized units) of HRV were significantly lower when compared with those of the control group. The MEHT and control groups did not differ from each other with respect to time or frequency domain measures of HRV. Comparison between the hypertensive groups showed that SDNN, total power, LF power and HF power were lower in the SEHT group compared with the MEHT group (P<0.05 for all). Among hypertensive patients RR-interval, age, gender, systolic finger blood pressure and diastolic office blood pressure as well as 24-h blood pressure were significant determinants of HRV. In conclusion, we found that the severity of chronic essential hypertension seems to be related to the severity of impairment of cardiac autonomic control.     

Holter ECG monitoring in patients with perceived electrical hypersensitivity.

Earlier studies have indicated that patients claiming to be sensitive to electromagnetic fields, so-called electrical hypersensitivity (EHS), have a dysbalance of the autonomic nervous system (ANS) regulation. This paper focuses on a possible dysbalance in the ANS among EHS patients by the use of long-term monitoring of electrocardiogram (ECG) in both a patient and a matched control group. At the same time, the environmental power frequency magnetic field was recorded for both groups in order to see if there was any difference in exposure between the groups. ECG, heart rate (HR) and heart rate variability (HRV) as well as the magnetic field exposure were monitored for 24 h. Fourteen patients with perceived EHS symptoms were selected from the University Hospital, Ume?, Sweden. Symptoms indicating autonomic nervous dysregulation were not part of the inclusion criteria of the patient group. Age and sex matched healthy subjects were used as controls. No differences were found between the groups regarding magnetic field exposure or the mean HR for 24 h. The HRV analyses showed that the high-frequency (HF) component did not have the expected increase with sleep onset and during nighttime in the EHS group. When separating the sleeping and awake time even less differences between the two conditions in the EHS patients, both for the low-frequency and HF components in the HRV spectrum, were seen. EHS patients had a disturbed pattern of circadian rhythms of HRV and showed a relatively 'flat' representation of hourly-recorded spectral power of the HF component of HRV.     

Dietary micronutrients/antioxidants and their relationship with bronchial asthma severity

BACKGROUND: Because little is known about micronutrient/antioxidant intake and asthma severity, we investigated dietary intake and plasma/serum levels of micronutrients/antioxidants in a group of asthma patients with various degrees of severity, and compared the results with healthy subjects. METHODS: A case control study was carried out on 118 asthma patients and 121 healthy subjects. The severity of the disease was classified by division of patients into four groups. Normal dietary micronutrient/antioxidant intake was estimated from a food frequency questionnaire. Plasma/serum levels of vitamins C, E, and A, selenium, magnesium, zinc, and platelet glutathione peroxidase (GSH-Px) activity were also determined. RESULTS: No differences in daily micronutrient/antioxidant intake were seen between patients and healthy subjects. The severity of the disease showed no significant relationship with micronutrient/antioxidant intake. There were no differences in plasma/serum levels in any of the micronutrients/antioxidants between healthy subjects and asthmatics. Nor were any differences found between asthma groups in severity in the biochemical measures, except in platelet GSH-Px activity, which was significantly lower in the most severe groups. CONCLUSIONS: In this study, we found no evidence of any association between micronutrient/antioxidant intake or plasma/serum levels of micronutrients/antioxidants and asthma. Reduction of platelet GSH-Px activity in the most severe patients suggests that these patients have a diminished capacity to restore part of the antioxidant defences.     

Effect of reflexological stimulation on heart rate variability

Analysis of heart rate variation (HRV) has become a popular non-invasive tool for assessing the activities of the autonomic nervous system (ANS). HRV analysis is based on the concept that fast fluctuations may specifically reflect changes of sympathetic and vagal activity. It shows that the structure generating the signal is not simply linear, but also involves non-linear contributions. These signals are essentially non-stationary and may contain indicators of cardiac health. This work is an attempt made to do a quantitative study on the effect of reflexology on the heart rate variability (HRV) during reflexologic stimulation. The non-linear parameters are evaluated for this study and the results obtained for 20 subjects are tabulated.     

The ameliorating effect of exogenous melatonin on urinary bladder function in hyperosmolar bladder overactivity and its influence on the autonomic nervous system activity

This study was designed to investigate the effects of melatonin on the bladder hyperactivity in hyperosmolar-induced overactive bladder (OAB) rats. Additionally, the influence of melatonin on the autonomic nervous system (ANS) using heart rate variability (HRV) analysis was assessed. 40 rats were divided into four groups: I--control (n = 12), II--rats with hyperosmolar OAB (n = 6), III--rats with melatonin pretreatment and hyperosmolar OAB (n = 6) and IV--control with melatonin pretreatment (n = 6). In group III and IV melatonin in dose of 100 mg/kg was given. HRV measurements in 10 rats, as follow: control (n = 2), control after melatonin treatment (n = 2), rats with hyperosmolar OAB without (n = 3), and after (n = 3) melatonin treatment were conducted. This study demonstrates marked influence of melatonin on urinary bladder activity in hyperosmolar-induced OAB rats. These rats showed significantly reduced the detrusor motor overactivity resulting in the improvement of cystometric parameters after melatonin treatment when compared to the control, as follow: a significant increase of intercontraction interval (70%) and functional bladder capacity (67%), as well as a decrease of the basal pressure, detrusor overactivity index and motility index of 96%, 439% and 40%, respectively. ANS activity analysis revealed sympathetic overactivity in OAB rats, and parasympathetic superiority in melatonin treated OAB rats. Melatonin treatment in rats with hyperosmolar OAB (group III) caused significant increase of nuHF parameter (from 51.00 +/- 25.29 to 76.97 +/- 17.43), as well as a decrease of nuLF parameter (from 49.01 +/- 25.26 to 23.03 +/- 17.43) and LF/HF ratio (from 1.280 +/- 0.980 to 0.350 +/- 0.330). In conclusion, melatonin suppresses hyperosmolar OAB, and modulates ANS activity by inhibition of the sympathetic drive. Therefore, melatonin may become a useful agent for OAB management.     

Effects of posture and acute sleep deprivation on heart rate variability

Purpose

In our previous study to investigate autonomic nervous system (ANS) activity due to radio frequency (RF) radiation using heart rate variability (HRV), drowsiness was observed in approximately half of all subjects. Therefore, the usage of HRV with unwanted drowsiness could falsely indicate the effects of RF radiation by mobile phones on the ANS. The objective of this study was to determine which posture is appropriate for accurate HRV analysis for provocation study.

Materials and Methods

A total of 52 healthy subjects (25 males and 27 females) participated in this experiment. We measured the number of times a subject showed drowsiness or sleep deprivation due to awakening, and analyzed HRV six times over 30 minutes in sitting and recumbent postures, using power spectrum.

Results

We employed the ratio of low frequency power to high frequency power (LFP/HFP) to analyze the changes in the ANS. The number of sleep deprivation occurrences in the sitting posture was significantly less than that in the recumbent posture (p<0.01), resulting in smaller increase of LFP/HFP. Although LFP/HFP of the two postures varied with time without any provocation, it was more stable in sitting than in recumbent postures.

Conclusion

A sitting posture is preferable to a recumbent posture for analyzing HRV, because of decreased drowsiness and sleep deprivation, thereby decreasing variation of LFP/HFP during experiment. Considering the drowsiness, it is also recommended that any experiment should be completed within 15 minutes, if possible.     

Inflammatory markers and Acid-base equilibrium in exhaled breath condensate of stable and unstable asthma patients

Background: Nitrosative and acid stress play an important role in the pathogenesis of asthma. The aim of this study was to evaluate whether, in asthmatics, a link exists between the concentrations of nitrite/nitrate, ammonia and pH values in exhaled breath condensate (EBC) and asthma severity, lung function, exhaled nitric oxide (F(ENO)), total IgE, eosinophil cationic protein (ECP) and blood eosinophilia. Methods: The above-mentioned parameters were measured in 19 healthy volunteers and 91 allergic asthmatics divided into three groups, i.e. 22 subjects with steroid-na?ve stable asthma, 35 with inhaled corticosteroid (ICS)-treated stable asthma and 34 with ICS-treated unstable asthma. Results: Compared with healthy subjects, EBC from asthmatics had significantly lower pH values and ammonia concentrations and significantly higher levels of nitrite/nitrate. The extent of these changes was higher in patients with unstable than in patients with steroid-na?ve and stable ICS-treated asthma. The EBC pH was positively correlated with ammonia and negatively correlated with nitrite/nitrate, F(ENO) or blood eosinophilia in all three groups of asthmatics. Significant positive correlations between EBC nitrite/nitrate and blood eosinophilia, ECP levels or F(ENO) were observed in all groups of asthmatics. Significant negative correlations between EBC ammonia and nitrite/nitrate, F(ENO), ECP concentrations or blood eosinophilia were demonstrated in the groups of ICS-na?ve and ICS-treated stable asthmatics. Conclusions: In asthmatic patients there is a relationship between EBC pH, ammonia and nitrite/nitrate concentrations and other recognized markers of airway inflammation. EBC pH values, ammonia and nitrite/nitrate levels measured together may help to assess airway inflammatory status and asthma severity.     

Immunogenetics of atopic asthma: association of DRB1*1101 DQA1*0501 DQB1*0301 haplotype with Dermatophagoides spp.-sensitive asthma in a sample of the Venezuelan population

BACKGROUND: Genes linked to the major histocompatibility complex (MHC), have been implicated in atopic asthma. Asthma is highly prevalent in the Venezuelan population (estimated at 20%) and genetic markers are needed to identify populations at risk and plan intervention strategies. OBJECTIVE: To study the influence of the MHC class I and class II genes in the susceptibility to atopic asthma. METHODS: MHC-class I HLA-A, -C, -B and MHC-class II HLA-DR, -DQ, -DP gene haplotype frequencies were determined in 135 Venezuelan mestizos, 71 belong to 20 atopic asthmatic families and 64 unrelated controls. The index cases were 20 atopic asthmatics with positive skin-prick tests and specific serum immunoglobulin E (IgE) for Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f). To ascertain the genes associated with susceptibility to atopy and/or asthma, two control groups were studied, 41 non-atopic subjects with skin-prick negative test, and undetectable levels of specific IgE and 23 non-asthmatic atopic subjects with detectable specific IgE to Der p and Der f. A linkage analysis was performed in those families with two or more atopic siblings (with or without asthma). RESULTS: MHC-class I genes analysis showed that HLA-Cw7 was absent in the asthmatic patients studied, whereas the frequency of this allele was 14.3% in non-atopic controls (P = 0.0 17, PC = 0.19) and 20.8% in the atopic controls (P = 0.0066, PC = 0.07). MHC-class II gene analysis showed a significant increase of the HLA-DRB1*11 in the asthmatic patients compared with non-atopic controls (allele frequencies of 25.6 vs 4.4% P = 0.0017, PC = 0.02). There were no significant differences among asthmatic and atopic controls in the frequency of HLA-DRB1*11 (25.6 vs 17.4%). In contrast, the HLA-DRB1*1101+ haplotypes were significantly higher in asthmatics compared with atopic and non-atopic controls (19.6% vs 2.2% vs 2.3%, PC<0.05). The HLA-DRB1*1101, DQA1*0501, DQB1*0301 haplotype was found significantly increased in the patients vs non-atopic controls (15.4 vs 1.1%, PC< 0.01). The serum levels of specific IgE were detectable in both atopic asthmatics and atopic controls; however, it was higher in atopic asthmatics vs atopic controls Der p (median, 58.7 vs 2.7 kU/L, P<0.001) and Der f (median, 46.9 vs 2.7 kU/L, P<0.001). No linkage between MHC genes and mite-atopy could be documented on informative families with two or more atopic siblings. CONCLUSIONS: We have identified an association between the haplotype HLA-DRB1*1101, DQA1*0501, DQB1*0301 and atopic asthma that confers susceptibility to develop mite-sensitive asthma to atopics (relative risk, RR 8.2), and to non-atopic controls (RR = 15.8) that carry this haplotype. Conversely, the allele HLA-Cw7 was absent in the asthmatics studied and had higher frequencies in the atopic (RR = 0.05) and non-atopic (RR = 0.08) controls. Thus, it may have a protective role for developing atopic asthma in the population studied.     

Body fat and blood lipids in postmenopausal women are related to resting autonomic nervous system activity

The present study investigated the activity of the autonomic nervous system (ANS), a major influence in normal physiological function, and its association with unfavorable postmenopausal states in body composition, lipid and/or glucose metabolism, or cardiovascular profiles. Body composition, blood pressure, and blood profiles of lipid and glucose of 175 postmenopausal women were measured. Resting ANS activity was assessed by heart rate variability (HRV) power spectral analysis. To scrutinize the influence of ANS activity levels on postmenopausal obesity-related factors, we divided the subjects into a low group ( < 220 ms²) and a high group ( > 220 ms²), based on the total power of HRV. Low-frequency (P < 0.01) and high-frequency power (P < 0.01) were both significantly lower in the low group. No significant difference was found in age, age at menopause, or years after menopause between the two groups. In contrast, body mass index (P < 0.05), percentages of body fat (P < 0.01), and systolic (P < 0.01) and diastolic (P < 0.01) blood pressure were significantly greater in the low group. As to blood lipid profiles, triglycerides (P < 0.05), total cholesterol (P < 0.05), and low-density lipoprotein cholesterol (P < 0.05) were significantly higher in the low group. Our findings indicate that reduced sympatho-vagal activity is associated with higher postmenopausal body fat content, blood pressure, and blood lipid concentrations. This study further implies that such autonomic depression could be a crucial risk factor in undermining the health and, ultimately, the quality of life, of postmenopausal women.     

Relation between exhaled carbon monoxide levels and clinical severity of asthma

Carbon monoxide (CO) can be detected in exhaled air and is increased in asthmatic patients not treated with corticosteroids. However, it is uncertain whether exhaled CO is related to severity of asthma. To study whether exhaled CO is related to severity of asthma in clinical courses, exhaled CO concentrations were measured on a CO monitor by vital capacity manoeuvre in 20 mild asthmatics treated with inhaled beta2-agonists alone, 20 moderate asthmatics treated with inhaled corticosteroids, and 15 stable asthmatics treated with high dose inhaled corticosteroids and oral corticosteroids once a month over 1 years. Exhaled CO concentrations were also measured in 16 unstable severe asthmatics who visited the hospital every 7 or 14 days for treatment with high dose inhaled corticosteroids and oral corticosteroids. The mean values of exhaled CO in severe asthma over 1 year were 6.7 +/- 9.5 p.p.m. (n = 31, mean +/- SD) and significantly higher than those of non-smoking control subjects (1.2 +/- 0.9 p.p.m., n = 20, P < 0.01). Exhaled CO concentrations in unstable severe asthmatics were significantly higher than those in stable severe asthmatics. However, exhaled CO concentrations in mild and moderate asthmatics did not differ significantly from those in non-smoking control subjects (P > 0.20). There was a significant relationship between the exhaled CO concentrations and forced expiratory volume in one second in all asthmatic patients. These findings suggest that exhaled CO concentrations may relate to the severity of asthma and measurements of exhaled CO concentrations may be a useful means of monitoring airway inflammation in asthma.     

Towards assessing the sympathovagal balance

Exact assessment of the autonomic nervous system’s (ANS) activity by means of heart rate variability (HRV) is a long-standing challenge. Although many techniques have been proposed to take up the challenge, none ever proposed a rationale for the approach behind the technique or a satisfying discrimination of the two activities which underlie the autonomic control of HRV. We here propose a new method, providing both an understanding of the discrimination’s nature and a framework which we believe leads to a thorough assessment of the sympathovagal balance, as a trajectory between points in a well-chosen space. The methodology assumes tools from scale invariance/covariance physics. The sympathovagal balance is obtained on a beat-to-beat basis with the dynamics portrayed through a trajectory. Furthermore, universal trajectories are sought which would comprehensively describe the effect of atropine and isoproterenol injections on systems underlying the heart pace variations. Non-invasive assessment of the respective activities of the sympathetic and parasympathetic subsystems of the ANS would be possible through cardiac autonomic measurements.     

A study of changes in the status of autonomic nervous system in primary open angle glaucoma cases

Control of Intra Ocular Pressure (IOP) is influenced by both divisions (sympathetic and para-sympathetic) of Autonomic Nervous System (ANS). The present study was conducted to confirm existence of any association of ANS with primary open angle glaucoma (POAG), if present. Systemic autonomic function tests were assessed in fifty patients of POAG with fifty normal subjects matched for sex and age as control using several well established tests based on cardiovascular reflex responses to standardised stimuli viz. Resting heart rate (RHR), Corrected QT Interval (QTc), T-wave amplitude, Standing to Lying Ratio (SLR); Valsalva Ratio; Galvanic Skin Resistance (GSR) and Cold Pressor Test (CPR). Tests were conducted in the Department of Physiology, Maulana Azad Medical College and associated Glaucoma Clinic of Guru Nanak Eye Centre from june '94-May '95. Subjects were randomly chosen from known POAG cases with IOP--25 +/- 5.08 mm Hg. The results showed decrease in both sympathetic and para-sympathetic activity of autonomic function tests in POAG suggesting associated autonomic dysfunction. Sympathetic under-activity is seen in 36 patients out of 50 (73%), POAG subjects while para-sympathetic activity is decreased in 43 of 50 (86%) of the POAG subjects when compared with normal control group. The results help concluding that POAG is associated with autonomic dysfunction with decreased activity of both sympathetic and para-sympathetic divisions of ANS.     

Role of symptoms and lung function in determining asthma control in smokers with asthma

Background:  Cigarette smoking in asthma increases the severity and accelerates the decline in lung function. The relative role of symptoms and lung function in determining asthma control in smokers with asthma is not known.
Aim of the study:  The aim of this study was to compare asthma control in smokers vs never-smokers with asthma, using the validated Juniper asthma control questionnaire (ACQ), and assess if any difference was because of a particular symptom or the forced expiratory volume in one second (FEV₁) value.
Methods:  This was a cross-sectional study of 134 asthmatics (74 never-smokers and 60 smokers) with ≥15% reversibility in FEV₁ after salbutamol. All subjects completed the ACQ, recording FEV₁ and asthma symptoms (night awakening, morning symptoms, dyspnoea, wheeze, activity limitation and use of reliever inhaler).
Results:  Compared with the never-smokers, smokers with asthma had significantly worse median (IQR) total asthma control score [1.6 (1.1–2.3) vs 2.8 (1.7–3.4); ( P  < 0.0001)] and in each of the six individual symptom question scores ( P  < 0.001), but no difference in FEV₁ levels ( P  = 0.908).
Conclusion:  Asthma control is significantly worse in asthmatics who smoke compared with never-smokers, with all symptoms related to asthma control uniformly worse in smokers, independent of FEV₁.     

以线性参数模型和信息分解方法评价QT变异性对心率变异性的响应

自主神经系统(ANS)的平衡对于规避与心脏相关的疾病风险具有重要意义。本课题运用频域的线性参数模型和非线性信息分解方法,分析QT变异性(QTV)对于心率变异性(HRV)的响应,揭示心脏自主神经的调节状态。使用来自THEW数据库的Holter数据,选用其中的正常组(Normal,n=186)和高心律失常和心源性猝死风险组(ESRD,n=41)进行对比。提取昼夜安静态各5 min RR间期(RRI)和相对应的QT间期(QTI)序列,计算频域参数QTV与HRV相关的百分占比(LR)和信息分解的RRI对于QTI的可预测性(PI),并结合RRI序列的时域、频域和符号动力学分析,探讨QTV对于HRV的响应在两组人群中可能的差异和发生机制。对于LR和PI,Normal组均表现出显著的昼夜差异,而ESRD组则均不存在,反映出ESRD组ANS交互作用的缺失。两组间同时段同指标对比时,低频段LR无显著差异,而在高频段,Normal组的LR值均显著小于同时段ESRD组的LR值(白天:18.36%±17.38% vs 39.37%±23.80%, P<0.05;夜晚: 28.63%±18.77% vs 42.31%±21.97%, P<0.05);Normal组夜晚的PI显著大于ESRD组夜晚的PI(0.310±0.155 vs 0.236±0.131, P<0.05),而在白天无显著差异。研究表明,线性参数模型和基于信息分解的非线性预测对自主神经活动的敏感性不同;高心律失常和心源性猝死风险人群中HRV对QTV的调控呈复杂度降低的特点。