Wearable pulmonary monitoring system with integrated functional lung imaging and chest sound recording: a clinical investigation in healthy subjects.

Objective.Current wearable respiratory monitoring devices provide a basic assessment of the breathing pattern of the examined subjects. More complex monitoring is needed for healthcare applications in patients with lung diseases. A multi-sensor vest allowing continuous lung imaging by electrical impedance tomography (EIT) and auscultation at six chest locations was developed for such advanced application. The aims of our study were to determine the vest's capacity to record the intended bio-signals, its safety and the comfort of wearing in a first clinical investigation in healthy adult subjects.Approach.Twenty subjects (age range: 23-65 years) were studied while wearing the vests during a 14-step study protocol comprising phases of quiet and deep breathing, slow and forced full expiration manoeuvres, coughing, breath-holding in seated and three horizontal postures. EIT, chest sound and accelerometer signals were streamed to a tablet using a dedicated application and uploaded to a back-end server. The subjects filled in a questionnaire on the vest properties using a Likert scale.Main results.All subjects completed the full protocol. Good to excellent EIT waveforms and functional EIT images were obtained in 89% of the subjects. Breathing pattern and posture dependent changes in ventilation distribution were properly detected by EIT. Chest sounds were recorded in all subjects. Detection of audible heart sounds was feasible in 44%-67% of the subjects, depending on the sensor location. Accelerometry correctly identified the posture in all subjects. The vests were safe and their properties positively rated, thermal and tactile properties achieved the highest scores.Significance.The functionality and safety of the studied wearable multi-sensor vest and the high level of its acceptance by the study participants were confirmed. Availability of personalized vests might further advance its performance by improving the sensor-skin contact.

Identification and analysis of stable breathing periods in electrical impedance tomography recordings.

Objective. In this paper, an automated stable tidal breathing period (STBP) identification method based on processing electrical impedance tomography (EIT) waveforms is proposed and the possibility of detecting and identifying such periods using EIT waveforms is analyzed. In wearable chest EIT, patients breathe spontaneously, and therefore, their breathing pattern might not be stable. Since most of the EIT feature extraction methods are applied to STBPs, this renders their automatic identification of central importance.Approach. The EIT frame sequence is reconstructed from the raw EIT recordings and the raw global impedance waveform (GIW) is computed. Next, the respiratory component of the raw GIW is extracted and processed for the automatic respiratory cycle (breath) extraction and their subsequent grouping into STBPs.Main results. We suggest three criteria for the identification of STBPs, namely, the coefficient of variation of (i) breath tidal volume, (ii) breath duration and (iii) end-expiratory impedance. The total number of true STBPs identified by the proposed method was 294 out of 318 identified by the expert corresponding to accuracy over 90%. Specific activities such as speaking, eating and arm elevation are identified as sources of false positives and their discrimination is discussed.Significance. Simple and computationally efficient STBP detection and identification is a highly desirable component in the EIT processing pipeline. Our study implies that it is feasible, however, the determination of its limits is necessary in order to consider the implementation of more advanced and computationally demanding approaches such as deep learning and fusion with data from other wearable sensors such as accelerometers and microphones.

Urinary microRNAs expression in prostate cancer diagnosis: a systematic review.

PURPOSE: Circulating microRNAs (miRNAs) have been shown to have the potential as noninvasive diagnosis biomarkers in several types of cancers, including prostate cancer (PCa). Urine-based miRNA biomarkers have been researched as an alternative tool in PCa diagnosis. However, few studies have performed miRNA detection in urine samples from PCa patients, as well as low numbers of miRNAs have been assayed, and there is a lack of standard strategies for validation. In this context, we conducted an in-depth literature review focusing on miRNAs isolated from urine samples that may contribute to the diagnosis of PCa. METHODS: A systematic review was performed searching the PubMed, Lilacs and Cochrane Library databases for articles focused on the value of significantly deregulated miRNAs as biomarkers in PCa patients. RESULTS: Only 18 primary manuscripts were included in this review, according to the search criteria. Our results suggest that miR-21-5p, miR-141-3p, miR-375 and miR-574-3p should be considered as potential urinary biomarkers for the diagnosis of PCa. CONCLUSION: These results suggested that large-scale prospective studies are still needed to validate our findings, using standardized protocols for analysis.

Physiologically motivated detection of Atrial Fibrillation.

Atrial Fibrillation (AF) is the most common arrhythmia and it is estimated to affect 33.5 million people worldwide. AF is associated with an increased risk of mortality and morbidity, such as heart failure and stroke and affects mostly older persons and persons with other conditions (e.g. heart failure and coronary artery disease). In order to prevent such life threatening and life quality reducing conditions it is essential to provide better algorithms, capable of being integrated in low-cost personalized health systems. This paper presents a new algorithm for AF detection, which is based on the analysis of the three physiological characteristics of AF: 1) Irregularity of heart rate and; 2) Absence of P-waves and 3) Presence of fibrillatory waves. Based on these characteristics several features were extracted from 12-lead electrocardiograms (ECG) and selected according to their discrimination ability. The classification between AF and non-AF episodes was performed using a Support Vector Machine (SVM) classification model. Our results show that the identification of the fibrillatory patterns, using the proposed features, extracted from the analysis of 12-lead ECG improves the performance of the algorithm to a sensitivity of 88.5% and specificity 92.9%, when compared to our previous single-channel approach, in the same database.

Detection of explosive cough events in audio recordings by internal sound analysis.

We present a new method for the discrimination of explosive cough events, which is based on a combination of spectral content descriptors and pitch-related features. After the removal of near-silent segments, a vector of event boundaries is obtained and a proposed set of 9 features is extracted for each event. Two data sets, recorded using electronic stethoscopes and comprising a total of 46 healthy subjects and 13 patients, were employed to evaluate the method. The proposed feature set is compared to three other sets of descriptors: a baseline, a combination of both sets, and an automatic selection of the best 10 features from both sets. The combined feature set yields good results on the cross-validated database, attaining a sensitivity of 92.3±2.3% and a specificity of 84.7±3.3%. Besides, this feature set seems to generalize well when it is trained on a small data set of patients, with a variety of respiratory and cardiovascular diseases, and tested on a bigger data set of mostly healthy subjects: a sensitivity of 93.4% and a specificity of 83.4% are achieved in those conditions. These results demonstrate that complementing the proposed feature set with a baseline set is a promising approach.

Telemonitorización del soporte ventilatorio domiciliario / Telemonitoring of domiciliary ventilatory support

More than 1,000 patients have been admitted to the pediatric ventilatory assistance program of the Chilean Ministry of Health. There are two subprograms depending on the complexity of patients. Since 2006 we have had the non-invasive home ventilatory assistance program (AVNI in Spanish) and the home invasive ventilatory assistance program (AVI in Spanish), derived from the AVNI program in 2008. Both provide coverage for patients under the age of 20, which complements the health network by delivering technology, home visits by professionals and respiratory supplies to ensure an adequate stay at the patients' homes with their families. It is in this context that remote telemonitoring emerges as an alternative to monitor the ventilatory therapy of these patients at home, which consists of remotely monitoring all ventilatory therapy; at present, there exist different tools to achieve this goal. The objective of this review is to describe the main telemonitoring systems available in Chile and their usefulness to check respiratory therapy in patients requiring home ventilatory support. As healthcare technology advances, the survival rate of patients requiring chronic ventilatory support increases; this situation, together with the high costs of hospital management for the health system and families, has brought about, in the last few years, the creation of home ventilatory support programs in Chile's public health system. In this context, telemonitoring emerges as a tool to optimize monitoring and timely adjustment of ventilatory parameters in patients receiving ventilatory support at home. It also seeks to reduce costs and increase safety

Actualmente han ingresado al programa de asistencia ventilatoria pediátrico del Ministerio de Salud de Chile más de 1000 pacientes. Existen dos sub programas dependiendo de la complejidad de los pacientes, es así como tenemos al programa de asistencia ventilatoria no invasiva domiciliaria (AVNI), que surgió durante el año 2006, y el programa de asistencia ventilatoria invasiva domiciliaria (AVI) que nace derivado del programa AVNI a partir del año 2008. Ambos entregan cobertura a pacientes menores de 20 años, complementando a la red de salud entregando la tecnología, visitas de profesionales en domicilio y una canasta de insumos respiratorios que aseguren una adecuada estancia en domicilio de los pacientes, junto a sus familias. Es en este contexto la telemonitorización a distancia surge como una alternativa para el seguimiento de la terapia ventilatoria de éstos pacientes en domicilio, la cual consiste en la monitorización en forma remota de toda la terapia ventilatoria , existiendo diferentes herramientas en la actualidad para llevala a cabo. El objetivo de esta revisión es describir los principales sistemas de telemonitorización disponibles en Chile, y su utilidad en la monitorización a distancia la terapia respiratoria de los pacientes que requieren soporte ventilatorio domiciliario. El avance de la tecnología sanitaría ha impactado en una mayor sobrevida de pacientes que requieren soporte ventilatorio crónico, el manejo hospitalario de estos pacientes tiene elevados costos para el sistema sanitario y las familias. En respuesta a esto durante los últimos años se han creado en el sistema público de salud de Chile programas de soporte ventilatorio domiciliario. En este contexto la telemonitorización surge como una herramienta que permite optimizar el seguimiento y el ajuste oportuno de los parámetros ventilatorios en los pacientes que reciben soporte ventiltorio domiciliario. Además busca disminuir los costos y aumentar la seguridad

Storage of Calophyllum brasiliense Cambess. seeds / Armazenamento de sementes de Calophyllum brasiliense Cambess

Abstract Calophyllum brasiliense is a species native to Brazil and has potential for use in the timber industry, in the reforestation of degraded areas, besides having medicinal properties. Its propagation is mainly by seeds which, depending on their recalcitrant characteristics, leads to difficulty in conservation, due to changes in its physiological potential during storage. Aiming to contribute to the expansion of its cultivation, rational use and conservation, the objective of this study was to investigate the behavior of C. brasiliense seeds during storage. Different packings (paper, aluminum and polyethylene) and environmental conditions (room temperature and cold chamber) were quarterly tested over 12 months, by evaluating germination viability and vigor. Based on the results, it was concluded that packaging in polyethylene and freezer storage provided the best conditions for the conservation of seeds, keeping them viable for a period of nine months.

Resumo Calophyllum brasiliense é uma espécie nativa do Brasil e está na lista de espécies recomendadas para o reflorestamento de áreas degradadas, além de possuir propriedades medicinais e madeireiras. Sua propagação se dá principalmente via sementes, as quais, em função das suas características recalcitrantes, apresentam dificuldade de conservação, devido a alterações no seu potencial fisiológico ao longo do armazenamento. Visando contribuir com a ampliação de seu cultivo, uso racional e conservação, objetivou-se investigar o comportamento das sementes de C. brasiliense durante 12 meses de armazenamento. Testou-se diferentes embalagens (papel, alumínio e polietileno) e condições ambientais (câmara fria e temperatura ambiente), avaliando-se trimestralmente a germinação, viabilidade e vigor. Com base nos resultados obtidos conclui-se que o acondicionamento em embalagem de polietileno e o armazenamento em câmara fria proporcionou a melhor condição para a conservação das sementes, mantendo essas viáveis por um período de nove meses.

Enhancement of the physicochemical properties of [Pt(dien)(nucleobase)]2+ for HIVNCp7 targeting.

Physicochemical properties of coordination compounds can be exploited for molecular recognition of biomolecules. The inherent π-π stacking properties of [Pt(chelate)(N-donor)]2+ ([PtN4]) complexes were modulated by systematic variation of the chelate (diethylenetriamine and substituted derivatives) and N-donor (nucleobase or nucleoside) in the formally substitution-inert PtN4 coordination sphere. Approaches to target the HIV nucleocapsid protein HIVNCp7 are summarized building on (i) assessment of stacking interactions with simple tryptophan or tryptophan derivatives to (ii) the tryptophan-containing C-terminal zinc finger and (iii) to the full two-zinc finger peptide and its interactions with RNA and DNA. The xanthosine nucleoside was identified as having significantly enhanced stacking capability over guanosine. Correlation of the LUMO energies of the modified nucleobases with the DFT π-stacking energies shows that frontier orbital energies of the individual monomers can be used as a first estimate of the π-stacking strength to Trp. Cellular accumulation studies showed no significant correlation with lipophilicity of the compounds, but all compounds had very low cytotoxicity suggesting the potential for antiviral selectivity. The conceptual similarities between nucleobase alkylation and platination validates the design of formally substitution-inert coordination complexes as weak Lewis acid electrophiles for selective peptide targeting.

Zygoparity and sex steroid hormone profiles in bluemouth Helicolenus dactylopterus.

Two hundred and seven individuals (103 females and 104 males) of bluemouth Helicolenus dactylopterus (Scorpaeniformes, Sebastidae), a commercially important deep-water species with an unusual reproductive strategy, from the eastern Atlantic Ocean ranging from 13·9 to 37·5 cm total length (LT ) were analysed from September 2011 to October 2012. The analysis included gonad maturity phases and blood-plasma levels of oestradiol-17ß (E2 ), 11-ketotestosterone (11-KT) and 17,20ß-dihydroxypregn-4-en-3-one (17,20ß-P). Results confirmed the existence of an annual reproductive cycle with asynchrony between females and males and a spawning season from January to May. A pronounced peak in 17,20ß-P in October for both sexes was associated with possible mating behaviour and recent copula. Levels of E2 increased preceding the elevation of the gonado-somatic index during ovarian growth and were lower during regression and regeneration. The frequency distribution of oocyte-embryonic stages and variation of hormone levels suggest the existence of daily rhythms. Fertilization was detected between 2000-0000 and 0800-1200 h and spawning took place throughout the day peaking between 2000 and 0000 h. The cyclic pattern of sex steroids and ovarian recruitment provides a new insight into the reproductive strategy of this species.

Storage of Calophyllum brasiliense Cambess. seeds.

Calophyllum brasiliense is a species native to Brazil and has potential for use in the timber industry, in the reforestation of degraded areas, besides having medicinal properties. Its propagation is mainly by seeds which, depending on their recalcitrant characteristics, leads to difficulty in conservation, due to changes in its physiological potential during storage. Aiming to contribute to the expansion of its cultivation, rational use and conservation, the objective of this study was to investigate the behavior of C. brasiliense seeds during storage. Different packings (paper, aluminum and polyethylene) and environmental conditions (room temperature and cold chamber) were quarterly tested over 12 months, by evaluating germination viability and vigor. Based on the results, it was concluded that packaging in polyethylene and freezer storage provided the best conditions for the conservation of seeds, keeping them viable for a period of nine months.

Cryogenic setup for trapped ion quantum computing.

We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less than ±20 nm over 2 s. In addition to the cryogenic apparatus, we describe the setup required for an operation with 40Ca+ and 88Sr+ ions. The instability of the laser manipulating the optical qubits in 40Ca+ is characterized by yielding a minimum of its Allan deviation of 2.4 ⋅ 10-15 at 0.33 s. To evaluate the performance of the apparatus, we trapped 40Ca+ ions, obtaining a heating rate of 2.14(16) phonons/s and a Gaussian decay of the Ramsey contrast with a 1/e-time of 18.2(8) ms.

Colo-colonic intussusception due to large submucous lipoma: A case report.

INTRODUCTION: Intussusception in adult is rarely caused by idiopathic conditions. Main causes are inflammatory diseases, benign or malignant tumors and motility disorders. As a benign cause, lipomas appear as a particularly rare gastrointestinal intraluminal tumor occurring with highest incidence in the colon, mostly in the caecum and ascending colon. PRESENTATION OF CASE: A 57-year-old male patient was admitted at the surgical emergency in Belo Horizonte, with history of chronic and intermittent diffuse abdominal pain, associated with variations of his bowel habits and rare episodes of vomiting starting around 3days prior to admission. DISCUSSION: Intussusception is the cause of adult symptomatic bowel obstruction in 1% of the cases and its colocolonic occurrence represents 17% of all intestinal intussusceptions in adults. The reported case presents itself as even rarer considering its evaluation according to the epidemiological statistics of 1:5 men/women ratio and lipoma's most common location being the right colon. Intussusception and intestinal obstructions caused by intraluminal lipomas are not often described in the literature and its occurrence is directly related to its size, usually larger than 2cm diameter. The management of lipomatous intraluminal lesions of the colon is traditionally surgical, and it allows a selective resection, depending on the size of the tumor, length of intussusception, and the amount of inflammation. CONCLUSION: Patients with chronic abdominal symptoms and semi-obstruction caused by intussusception are rarely diagnosed before surgery unless there is a high index of suspicion. Colonoscopy contributes to diagnosis given that it provides direct visualization and biopsy.

Culture of domestic cat ovarian tissue in vitro and in the chick embryo chorioallantoic membrane.

In vitro culture and transplantation procedures are essential protocols employed in the evaluation of ovarian follicle survival and development. Culture in the chorioallantoic membrane (CAM) of chick embryos is an intermediate method that provides important follicle development information and has not been tested for cat ovaries to date. The aim of this study was to investigate if in vitro and CAM culture could be used as short-term systems to study cat ovarian tissue development. The ovaries of eight cats were dissected into 3-mm(3) cubes, cultured in vitro and in CAM for up to 5 days, and stained with hematoxylin-eosin and Gomori trichrome. Cell proliferation was analyzed using anti-Ki67. Possible differences among groups were investigated by analysis of variance or the Kruskal-Wallis test followed by Bonferroni correction. The T-test or Wilcoxon test was used to verify differences between the CAM and IVC. Results revealed that 87.5% of all follicles were primordial during culture. The percentage of primordial follicles in the morphologically normal follicles (MNF) pool was always higher than 80%, with the exception of Day 3 of CAM culture, but the number of MNF reduced significantly from Day 0 (600 out of 777 follicles) to Day 5 in the CAM (91 out of 171) and IVC (296 out of 686). The number of primordial follicles in 1 mm(3) in Days 2, 3, and 5 in the CAM was significantly lower than that in the control (Day 0). No cellular proliferation was observed in culture. Vascularization occurred in the CAM culture, but with no association to follicular viability. In addition, both methods showed an increase in connective tissue during culture. Although no significant differences were observed in the percentage of MNF, there was a reduction in the total number of follicles, both for IVC and CAM-cultured ovarian tissue. Furthermore, anti-Ki67 did not stain any follicle after Day 0 in IVC or in CAM culture. Neither system was capable of promoting follicle growth and/or development. The results show that the CAM is not a suitable system for feline ovarian tissue and highlight the necessity to improve IVC systems in cats.

Influence of torso and arm positions on chest examinations by electrical impedance tomography.

Electrical impedance tomography (EIT) is increasingly used in patients suffering from respiratory disorders during pulmonary function testing (PFT). The EIT chest examinations often take place simultaneously to conventional PFT during which the patients involuntarily move in order to facilitate their breathing. Since the influence of torso and arm movements on EIT chest examinations is unknown, we studied this effect in 13 healthy subjects (37 ± 4 years, mean age ± SD) and 15 patients with obstructive lung diseases (72 ± 8 years) during stable tidal breathing. We carried out the examinations in an upright sitting position with both arms adducted, in a leaning forward position and in an upright sitting position with consecutive right and left arm elevations. We analysed the differences in EIT-derived regional end-expiratory impedance values, tidal impedance variations and their spatial distributions during all successive study phases. Both the torso and the arm movements had a highly significant influence on the end-expiratory impedance values in the healthy subjects (p = 0.0054 and p < 0.0001, respectively) and the patients (p < 0.0001 in both cases). The global tidal impedance variation was affected by the torso, but not the arm movements in both study groups (p = 0.0447 and p = 0.0418, respectively). The spatial heterogeneity of the tidal ventilation distribution was slightly influenced by the alteration of the torso position only in the patients (p = 0.0391). The arm movements did not impact the ventilation distribution in either study group. In summary, the forward torso movement and the arms' abduction exert significant effects on the EIT waveforms during tidal breathing. We recommend strict adherence to the upright sitting position during PFT when EIT is used.

Real-Time Prediction of Neurally Mediated Syncope.

Neurally mediated syncope (NMS) patients suffer from sudden loss of consciousness, which is associated with a high rate of falls and hospitalization. NMS negatively impacts a subject's quality of life and is a growing cost issue in our aging society, as its incidence increases with age. In this paper, we present a solution for prediction of NMS, which is based on the analysis of the electrocardiogram (ECG) and photoplethysmogram (PPG) alone. Several parameters extracted from ECG and PPG, associated with reflectory mechanisms underlying NMS in previous publications, were combined in a single algorithm to detect impending syncope. The proposed algorithm was evaluated in a population of 43 subjects. The feature selection, distance metric selection, and optimal threshold were performed in a subset of 30 patients, while the remaining data from 13 patients were used to test the final solution. Additionally, a leave-one-out cross-validation scheme was also used to evaluate the performance of the proposed algorithm yielding the following results: sensitivity (SE)--95.2%; specificity (SP)--95.4%; positive predictive value (PPV)--90.9%; false-positive rate per hour (FPRh)-0.14 h(-1), and prediction time (aPTime)--116.4 s.

Detection of crackle events using a multi-feature approach.

The automatic detection of adventitious lung sounds is a valuable tool to monitor respiratory diseases like chronic obstructive pulmonary disease. Crackles are adventitious and explosive respiratory sounds that are usually associated with the inflammation or infection of the small bronchi, bronchioles and alveoli. In this study a multi-feature approach is proposed for the detection of events, in the frame space, that contain one or more crackles. The performance of thirty-five features was tested. These features include thirty-one features usually used in the context of Music Information Retrieval, a wavelet based feature as well as the Teager energy and the entropy. The classification was done using a logistic regression classifier. Data from seventeen patients with manifestations of adventitious sounds and three healthy volunteers were used to evaluate the performance of the proposed method. The dataset includes crackles, wheezes and normal lung sounds. The optimal detection parameters, such as the number of features, were chosen based on a grid search. The performance of the detection was studied taking into account the sensitivity and the positive predictive value. For the conditions tested, the best results were obtained for the frame size equal to 128 ms and twenty-seven features.

Detection of different types of noise in lung sounds.

Lung sound signal processing has proven to be a great improvement to the traditional acoustic interpretation of lung sounds. However, that analysis can be seriously hindered by the presence of different types of noise originated in the acquisition environment or caused by physiological processes. Consequently, the diagnostic accuracy of pulmonary diseases can be severely affected, especially if the implementation of telemonitoring systems is considered. The present study is focused on the implementation of an algorithm able to identify noisy periods, either voluntarily (vocalizations, chest movement and background voices) or involuntarily produced during acquisitions of lung sounds. The developed approach also had to deal with the presence of simulated cough events, that carry important diagnostic information regarding several pulmonary diseases. Features such as Katz fractal dimension, Teager-Kaiser energy operator and normalized mutual information, were extracted from the time domain of healthy and a pathological lung signals. Noise detection was the result of a good discrimination between uncontaminated lung sounds and both cough and noise episodes and a slightly worse classification of cough events. In fact, detection of cough periods carrying diagnostic information was influenced by the presence of two other types of noise having similar signal characteristics.

Evaluation of lung ventilation distribution in chronic obstructive pulmonary disease patients using the global inhomogeneity index.

The global inhomogeneity (GI) index is a electrical impedance tomography (EIT) parameter that quantifies the tidal volume distribution within the lung. In this work the global inhomogeneity index was computed for twenty subjects in order to evaluate his potential use in the detection and follow up of chronic obstructive pulmonary disease (COPD) patients. EIT data of 17 subjects were acquired: 14 patients with the main diagnoses of COPD and 3 healthy subjects which served as a control group. Two or three datasets of around 30 seconds were acquired at 33 scans/s and analysed for each subject. After reconstruction, a tidal EIT image was computed for each breathing cycle and a GI index calculated from it. Results have shown significant differences in GI values between the two groups (0.745 ± 0.007 for COPD and 0.668 ± 0.006 for lung-healthy subject, p <; 0.005). The GI values obtained for each subject have shown small variance between them, which is a good indication of stability. The results suggested that the GI may be useful for the identification and follow up of ventilation problems in patients with COPD.

Assessment of cardiovascular function from multi-Gaussian fitting of a finger photoplethysmogram.

Monitoring of cardiovascular function on a beat-to-beat basis is fundamental for protecting patients in different settings including emergency medicine and interventional cardiology, but still faces technical challenges and several limitations. In the present study, we propose a new method for the extraction of cardiovascular performance surrogates from analysis of the photoplethysmographic (PPG) signal alone.We propose using a multi-Gaussian (MG) model consisting of five Gaussian functions to decompose the PPG pulses into its main physiological components. From the analysis of these components, we aim to extract estimators of the left ventricular ejection time, blood pressure and vascular tone changes. Using a multi-derivative analysis of the components related with the systolic ejection, we investigate which are the characteristic points that best define the left ventricular ejection time (LVET). Six LVET estimates were compared with the echocardiographic LVET in a database comprising 68 healthy and cardiovascular diseased volunteers. The best LVET estimate achieved a low absolute error (15.41 ± 13.66 ms), and a high correlation (ρ = 0.78) with the echocardiographic reference.To assess the potential use of the temporal and morphological characteristics of the proposed MG model components as surrogates for blood pressure and vascular tone, six parameters have been investigated: the stiffness index (SI), the T1_d and T1_2 (defined as the time span between the MG model forward and reflected waves), the reflection index (RI), the R1_d and the R1_2 (defined as their amplitude ratio). Their association to reference values of blood pressure and total peripheral resistance was investigated in 43 volunteers exhibiting hemodynamic instability. A good correlation was found between the majority of the extracted and reference parameters, with an exception to R1_2 (amplitude ratio between the main forward wave and the first reflection wave), which correlated low with all the reference parameters. The highest correlation ([Formula: see text] = 0.45) was found between T1_2 and the total peripheral resistance index (TPRI); while in the patients that experienced syncope, the highest agreement ([Formula: see text] = 0.57) was found between SI and systolic blood pressure (SBP) and mean blood pressure (MBP).In conclusion, the presented method for the extraction of surrogates of cardiovascular performance might improve patient monitoring and warrants further investigation.

Hypoglycemic Effect of the Methanol flower Extract of Piper Claussenianum and the Major Constituent 2',6'-dihydroxy-4'-methoxychalcone in Streptozotocin Diabetic Rats.

Piper claussenianum inflorescences crude methanol extract was tested for hypoglycemic effect in streptozotocin-induced diabetic rats. The blood glucose levels of rats treated with methanol extract were reduced from 318.4±28.1 mg/dl before treatment to 174.2±38.3 mg/dl after 12 days of treatment (P<0.05). Phytochemical studies were carried out on inflorescences methanol crude extract in order to investigate the possible metabolites responsible for the pharmacological properties of the extract. After chromatographic procedures, three flavonoids were isolated and characterized. The major compound 2',6'-dihydroxy-4'-methoxychalcone was also tested. Rats that received the chalcone content also displayed a reduction in blood glucose levels from 277.4±7.7 mg/dl before treatment to 158.8±9.2 mg/dl after 12 days of treatment (P<0.05). The results suggest this chalcone is one of the metabolite responsible for the blood glucose levels reduction in rats with streptozotocin-induced diabetes. The inflorescence crude extract of P. claussenianum was found to be composed mainly by flavonoids and may be a potential natural source of compounds with hypoglycemic properties.