Simultaneous encoding of tactile information by three primate cortical areas

We used simultaneous multi-site neural ensemble recordings to investigate the representation of tactile information in three areas of the primate somatosensory cortex (areas 3b, SII and 2). Small neural ensembles (30-40 neurons) of broadly tuned somatosensory neurons were able to identify correctly the location of a single tactile stimulus on a single trial, almost simultaneously. Furthermore, each of these cortical areas could use different combinations of encoding strategies, such as mean firing rate (areas 3b and 2) or temporal patterns of ensemble firing (area SII), to represent the location of a tactile stimulus. Based on these results, we propose that ensembles of broadly tuned neurons, located in three distinct areas of the primate somatosensory cortex, obtain information about the location of a tactile stimulus almost concurrently.     

Elderly Cardiac Rehabilitation Patients Show Greater Improvements in Ventilation at Submaximal Levels of Exercise

The minute ventilation (VE) and carbon dioxide output (VCO&sub2;) adaptations to 12 weeks of cardiac rehabilitation were investigated in diagnosis-matched elderly patients (ELD) and younger patients (YNG). Thirty ELD (25 males, 5 females; age equals 69.2?+/-3.9 years) and 30 YNG (27 males, 3 females; age equals 48.3?+/-7.0 years) were exercise tested at program entry (T1) and completion (T2). Peak oxygen uptake (VO&sub2; peak) and ventilatory threshold (VT) (ml kg-1 min-1) were greater for YNG at both T1 and T2 (p is less than 0.01). Both ELD and YNG showed significant T1 to T2 improvements (p is less than 0.01) for VO&sub2; peak (21.1% and 23.4%) and VT (20.1% and 12.4%). The VE/VCO&sub2; ratio was greater (p is less than 0.01) for ELD but approached YNG values after training. The VCO&sub2;/VO&sub2; slope showed a greater T1 to T2 reduction in ELD (12.4% vs 3.4%). There was no relationship (r(2) equals 0.15; NS) between the percentage change in VO&sub2; peak and VE/VCO&sub2; indicating unrelated mechanisms of improvement. We conclude that ELD showed similar improvements in VO&sub2; peak but greater improvements in their ventilatory tolerance for submaximal exercise. These changes indicate improvements in aging-enhanced exercise ventilation, are important for performance of normal activities of daily living, and would have been undetectable without gas exchange analysis.     

Fetal Electrocardiogram Extraction and Analysis Using Adaptive Noise Cancellation and Wavelet Transformation Techniques

Birth defect-related demise is mainly due to congenital heart defects. In the earlier stage of pregnancy, fetus problem can be identified by finding information about the fetus to avoid stillbirths. The gold standard used to monitor the health status of the fetus is by Cardiotachography(CTG), cannot be used for long durations and continuous monitoring. There is a need for continuous and long duration monitoring of fetal ECG signals to study the progressive health status of the fetus using portable devices. The non-invasive method of electrocardiogram recording is one of the best method used to diagnose fetal cardiac problem rather than the invasive methods.The monitoring of the fECG requires development of a miniaturized hardware and a efficient signal processing algorithms to extract the fECG embedded in the mother ECG. The paper discusses a prototype hardware developed to monitor and record the raw mother ECG signal containing the fECG and a signal processing algorithm to extract the fetal Electro Cardiogram signal. We have proposed two methods of signal processing, first is based on the Least Mean Square (LMS) Adaptive Noise Cancellation technique and the other method is based on the Wavelet Transformation technique. A prototype hardware was designed and developed to acquire the raw ECG signal containing the mother and fetal ECG and the signal processing techniques were used to eliminate the noises and extract the fetal ECG and the fetal Heart Rate Variability was studied. Both the methods were evaluated with the signal acquired from a fetal ECG simulator, from the Physionet database and that acquired from the subject. Both the methods are evaluated by finding heart rate and its variability, amplitude spectrum and mean value of extracted fetal ECG. Also the accuracy, sensitivity and positive predictive value are also determined for fetal QRS detection technique. In this paper adaptive filtering technique uses Sign-sign LMS algorithm and wavelet techniques with Daubechies wavelet, employed along with de noising techniques for the extraction of fetal Electrocardiogram.Both the methods are having good sensitivity and accuracy. In adaptive method the sensitivity is 96.83, accuracy 89.87, wavelet sensitivity is 95.97 and accuracy is 88.5. Additionally, time domain parameters from the plot of heart rate variability of mother and fetus are analyzed.     

Acute severe asthma

Acute exacerbations of asthma are very common reasons for a presentation to emergency departments. This paper focuses on defining the high‐risk group, consideration of the concept of phenotypes of acute asthma, the assessment of severe and life‐threatening exacerbations and an emphasis on the management of the more severe end of the exacerbation severity. A number of evidence‐based guidelines exist throughout the world and are all slightly different. This reflects the poor evidence base for some of those recommendations. Thus, a large variation of treatment drugs, doses and regimen are used and clearly not standardised. This paper aims to present a summary of the best evidence and discuss some of these controversies. The most important aspect of treating an exacerbation of acute asthma is to review regularly and assess response to treatment. Severe and life‐threatening episodes should be treated with early use of intravenous treatment in a stepwise manner following the local guidelines. Non‐invasive ventilation and high flow nasal cannulae delivery of oxygen in the emergency department are evolving modalities, but evidence for their use is currently limited.     

Extracellular nucleotide signaling in solid organ transplantation

The role of extracellular purine nucleotides, including adenosine triphosphate (ATP) and adenosine, as modulators of posttransplantation outcome and ischemia‐reperfusion injury is becoming increasingly evident. Upon pathological release of ATP, binding and activation of P2 purinergic surface receptors promote tissue injury and inflammation, while the expression and activation of P1 receptors for adenosine have been shown to attenuate inflammation and limit ischemia‐induced damage, which are central to the viability and long‐term success of allografts. Here we review the current state of the transplant field with respect to the role of extracellular nucleotide signaling, with a focus on the sources and functions of extracellular ATP. The connection between ischemia reperfusion, purinergic signaling, and graft preservation, as well as the role of ATP and adenosine as driving factors in the promotion and suppression of posttransplant inflammation and allograft rejection, are discussed. We also examine novel therapeutic approaches that take advantage of the ischemia‐reperfusion‐responsive and immunomodulatory roles for purinergic signaling with the goal of enhancing graft viability, attenuating posttransplant inflammation, and minimizing complications including rejection, graft failure, and associated comorbidities.     

Lung transplant reperfusion injury involves pulmonary macrophages and circulating leukocytes in a biphasic response

OBJECTIVE: Both donor pulmonary macrophages and recipient circulating leukocytes may be involved in reperfusion injury after lung transplantation. By using the macrophage inhibitor gadolinium chloride and leukocyte filters, we attempted to identify the roles of these two populations of cells in lung transplant reperfusion injury. METHODS: With our isolated, ventilated, blood-perfused rabbit lung model, all groups underwent lung harvest followed by 18-hour cold storage and 2-hour blood reperfusion. Measurements of pulmonary artery pressure, lung compliance, and arterial oxygenation were obtained. Group I (n = 8) served as a control. Group II (n = 8) received gadolinium chloride at 14 mg/kg 24 hours before lung harvest. Group III (n = 8) received leukocyte-depleted blood reperfusion by means of a leukocyte filter. RESULTS: The gadolinium chloride group had significantly improved arterial oxygenation and pulmonary artery pressure measurements compared with control subjects and an improved arterial oxygenation compared with the filter group after 30 minutes of reperfusion. After 120 minutes of reperfusion, however, the filter group had significantly improved arterial oxygenation and pulmonary artery pressure measurements compared with the control group and an improved arterial oxygenation compared with the gadolinium chloride group. CONCLUSIONS: Lung transplant reperfusion injury occurs in two phases. The early phase is mediated by donor pulmonary macrophages and is followed by a late injury induced by recipient circulating leukocytes.     

Retinoic acid enhances lung growth after pneumonectomy

BACKGROUND: We sought to identify the role of retinoic acid (RA) upon lung growth. RA has a role in perinatal lung development, and we hypothesized that exogenous RA would enhance postpneumonectomy compensatory lung growth. METHODS: Utilizing the postpneumonectomy rat model, we studied the impact of RA upon contralateral lung growth. Adult Sprague-Dawley rats were divided into three groups. Group S underwent a sham left thoracotomy, group P underwent left pneumonectomy, and group R underwent left pneumonectomy with administration of exogenous RA (0.5 microg/g/day intraperitoneally). We then quantitated right lung growth after 10 and 21 days. Lung weight and volume were expressed as a ratio to the final body weight (lung weight and volume indices, LWI and LVI). Epidermal growth factor receptor (EGFR) expression was quantitated using Western blot analysis. Cellular proliferation index (CPI) was determined using BrdU immunostaining. RESULTS: LWI, LVI, CPI, and EGFR expression at 21 days were significantly higher in group R versus S and P. At the 10-day interval, both LWI and LVI were significantly higher in group R versus S and P. CONCLUSIONS: RA administration markedly enhances lung growth after pneumonectomy, as evidenced by increases in LWI, LVI, and CPI. Upregulation of EGFR expression was associated with these effects.