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1.
Zootaxa ; 5158(1): 1-67, 2022 Jun 27.
Article in English | MEDLINE | ID: mdl-36095561

ABSTRACT

We present a review of the genus Xylocopa (Neoxylocopa) of Mexico and Mesoamerica in which 11 species are recognized, including: X. clarionenis, X. fimbriata, X. frontalis, X. gualanensis, X. mexicanorum, X. nautlana, X. ocellaris, X. sonorina, X. wilmattae. Additionally, two new species are described, X. griswoldi sp. nov. with distribution in the United States and Mexico, and X. maya sp. nov. present in Mexico and Belize. Three species groups within the subgenus Neoxylocopa are recognized: frontalis, mexicanorum and sonorina. Identification keys are presented for identifying species groups and species. Furthermore, images of species and morphological structures as well as information regarding distribution are provided.


Subject(s)
Hymenoptera , Animals , Bees , Head , Mexico
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 5446-5449, 2021 11.
Article in English | MEDLINE | ID: mdl-34892358

ABSTRACT

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease that can lead to chronic arterial hypoxemia, hypercapnia, and dyspnea. To improve clinical symptoms in IPF patients, supplemental oxygen (SupplO2) has been prescribed with the aim to maintain SpO2 level, and consequently to relieve dyspnea, increase physical activity and improve quality of life. In this study, we investigated the effect of disease and short-term SupplO2 on cardiovascular and respiratory autonomic regulation. Linear and nonlinear indices were extracted from the beat-to-beat variability of heart rate (HR), systolic (SYS) blood pressure and respiration (RESP) in IPF patients and healthy subjects spontaneously breathing ambient air (AA) and during SupplO2 at 3 L/min. It was found that the effects on autonomic nervous systems (ANS) regulation were better demonstrated by the Granger causality (GC) method. GC was significantly higher (p<0.01) in patients compared to controls for the interactions RESP→SYS and BBI→SYS.Clinical Relevance-Short-term SupplO2 in IPF could adversely affect systolic blood pressure variability in particular. This study may help in the management of SupplO2 administration.


Subject(s)
Cardiovascular System , Idiopathic Pulmonary Fibrosis , Humans , Idiopathic Pulmonary Fibrosis/therapy , Oxygen , Quality of Life , Respiratory Rate
3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 702-705, 2020 07.
Article in English | MEDLINE | ID: mdl-33018084

ABSTRACT

Diverse analysis techniques have been used to comprehend the regulation by the autonomic nervous system (ANS) of the cardiovascular system when a human being faces a stressor. Recently, however, the complete ensemble empirical mode decomposition (EMD) with adaptive noise (CEEMDAN) allows analyzing nonstationary signals in a nonlinear and time- variant way. Consequently, CEEMDAN may provide a means to obtain clues about ANS regulation in health and disease. In this study, we analyze the average Hilbert-Huang spectrum (HHS) of cardiovascular variability signals by CEEMDAN during a head-up tilt test (HUTT) in 12 healthy female subjects and 18 orthostatic intolerance female patients. Beat-to-beat intervals (BBI) as well as systolic (SYS) blood pressure variability time series were analyzed. In addition, instantaneous amplitudes and frequencies of specific intrinsic mode functions (IMF) were investigated separately to define the influence of the disease on ANS regulation. Female groups demonstrated statistical differences in the high-frequency band of BBI but higher differences for the high and low-frequency bands of SYS from the mechanical transition of HUTT.Clinical Relevance- A relevant outcome of the study is the average HHS of healthy female subjects along HUTT. This HHS may be used as reference to help diagnose OI when HHS of the cardiovascular variability signals of any subject deviates from the normal course.


Subject(s)
Cardiovascular System , Orthostatic Intolerance , Autonomic Nervous System , Female , Humans , Standing Position , Tilt-Table Test
4.
Rev. int. med. cienc. act. fis. deporte ; 19(74): 197-208, jun. 2019. graf, tab
Article in Spanish | IBECS | ID: ibc-183687

ABSTRACT

Objetivo: El objetivo de este estudio fue evaluar la respuesta cardíaca aguda después de realizar una sesión de ejercicio con oclusión vascular en adultos mayores (AM). Sujetos y método: 22 participantes voluntarios, fueron sometidos al protocolo experimental de ejercicio dinámico de prensión manual con un 30% de presión de oclusión (PO), después de registrar los valores basales y en reposo de presión arterial sistólica (PAS), presión arterial diastólica (PAD) y frecuencia cardíaca (FC). Evaluadas en condiciones basales y entre los 5 y 30 minutos post-oclusión. Resultados: Al finalizar el protocolo se observó una reducción significativa en la PAS y FC a los 15', 20' y 25' (p<0,05) y para la PAD a los 10' y 20' (p<0,05). Conclusión: El efecto agudo del ejercicio con oclusión vascular genera una reducción significativa de PAS, PAD y FC hasta 25 minutos post-oclusión, en los AM analizados


The objective of this study was to evaluate the acute cardiac response after performing an exercise session with vascular occlusion in elderly adults (EA). Twenty-two volunteer participants underwent the experimental protocol of dynamic manual grip exercise with 30% occlusion pressure (OP), after recording the baseline values and resting systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR). All measures were taken in basal conditions and between 5 and 30 minutes' post-occlusion. At the end of the protocol, there was a significant reduction in SBP and HR at 15 ', 20' and 25 '(p <0.05) and for DBP at 10' and 20 '(p <0.05).). The acute effect of exercise with vascular occlusion generates a significant reduction of SBP, Basal Diastolic Pressure (BDP) and HR up to 25 minutes' post-occlusion, in the EA analyzed


Subject(s)
Humans , Male , Female , Middle Aged , Aged , Post-Exercise Hypotension/complications , Post-Exercise Hypotension/therapy , Therapeutic Occlusion/methods , Physical Exertion/physiology , Therapeutic Occlusion/instrumentation , Arterial Pressure/physiology , Heart Rate , Body Weight , Body Mass Index
5.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 5987-5990, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31947211

ABSTRACT

Monitoring uterine activity by electrohysterogram (EHG), associated with contractions both in pregnancy and labor, may contribute to the knowledge for evaluating possible risks to the binomial mother-fetus. In this context, the aim of the present study was to explore the complexity of EHG generated by women during the third trimester of pregnancy (group P) and at term labor (group L). The EHG was obtained by band-pass filtering in the range from 0.1 to 3 Hz the monopolar raw signal of the electrode number 1, of a 4-by-4 sensor array, which was located near to the tocodynamometer transducer. Multiscale entropy (MSE) analysis measures the entropy over multiple time scales to provide the complexity of the EHG time series. The results pointed out that such nonlinear technique has the potential to discriminate contractions from both groups using the area under the MSE curve (AUC) as index. The highest complexity was obtained for group P (N= 8) as AUC was 13.9233 ± 0.2015 while the lowest complexity was for group L, with N=8 and AUC of 5.1675 ± 0.0783 (p<; 0.0001). Consequently, the complexity of EHG by MSE could provide an index to discriminate between the electrical uterine activity generated during pregnancy or at labor.


Subject(s)
Labor, Obstetric , Uterine Contraction , Uterine Monitoring , Electromyography , Entropy , Female , Humans , Pregnancy , Uterus/physiology
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 6359-6362, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31947297

ABSTRACT

The aim of this study was to investigate the temporal dynamic behavior of cardiovascular interactions between heart period and systolic blood pressure during a 20-min head-up tilt test at 70° in young women with orthostatic intolerance compared to healthy women. Methods included the lagged and extended partial directed coherence applied to short-term windows shifted by 5 seconds, extracted from a multivariate set of cardiovascular and respiratory time series. Findings revealed significantly increased information flow (p <; 0.01) in patients from: a) heart period to blood pressure during supine position which subsequently decreased and b) blood pressure to heart period during the progression of orthostatic phase. Controls developed balanced cardiovascular interactions with smaller information flows than patients.


Subject(s)
Blood Pressure , Cardiovascular System , Orthostatic Intolerance , Female , Heart Rate , Humans , Standing Position , Tilt-Table Test
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 2957-2960, 2018 Jul.
Article in English | MEDLINE | ID: mdl-30441020

ABSTRACT

The aim of this study was to investigate the effect of head-up tilt (HUT) test on male and female young patients, diagnosed with orthostatic intolerance (OI), in comparison to male and female healthy subjects. Twenty seven OI patients (21 women, 6 men) and 26 age-matched healthy subjects (13 women, 13 men) were enrolled in a 70° HUT test. In addition to hemodynamic variables, cardiovascular and respiratory parameters were determined using linear and nonlinear methods to analyze heart rate (HRV) and blood pressure variability (BPV). During the complete test, HRV was lower in healthy men than in female controls. Decreased HRV and increased BPV were observed in female patients compared to healthy women. Furthermore, systolic BPV was increased in male and female patients. However, linear (rmssd) and nonlinear (plvar2) parameters indicated that diastolic BPV decreased in male patients during orthostatic phase, but remained unchanged in female patients. Findings indicated gender dependent mechanisms for the regulation of diastolic blood pressure during orthostatic stress in patients.


Subject(s)
Cardiovascular System , Orthostatic Intolerance , Blood Pressure , Female , Heart Rate , Humans , Male , Tilt-Table Test
8.
Med Eng Phys ; 61: 51-60, 2018 11.
Article in English | MEDLINE | ID: mdl-30270005

ABSTRACT

The present study investigates the instantaneous coupling among the cardiac, vascular, and respiratory systems, using the heart rate, respiration, and systolic and diastolic blood pressure variability in 12 healthy and 16 vasovagal syncope female subjects during a head-up tilt (HUT) testing protocol at 70° This study contributes to the coupling analysis by using a nonlinear joint symbolic dynamics (JSD) in a high-temporal resolution scheme, based on 5 min segments of the time series that are shifted every minute. For each segment, a bivariate JSD matrix was constructed to obtain global and local coupling indices in accordance to Shannon's entropy and the probability of occurrence of various bivariate words, respectively. The novel approach revealed important findings in the coupling dynamics of the systems, thus allowing the detection of group differences during the early orthostatic phase, and during the HUT test, before the occurrence of any pre-syncopal symptoms. In patients, the global indices indicated a significant decrease of cardiovascular coupling, starting at 10 min after the tilt-up, manifested by reduced baroreflex sensitivity and cardiorespiratory coupling that was initiated 8 min after the onset of the orthostatic phase (OP). A decreased autonomic control on cardiovascular-respiratory couplings was further evidenced by increased alterations of the JSD indices during the OP compared to the supine position in patients compared to controls. Furthermore, findings based on local indices demonstrated that female patients showed reductions and disengagements in cardiovascular (p < 0.001) and cardiorespiratory (p < 0.01) couplings, as early as the first 5 min and during the complete OP.


Subject(s)
Cardiovascular System/physiopathology , Respiration , Stress, Physiological , Syncope, Vasovagal/physiopathology , Adult , Case-Control Studies , Female , Humans , Nonlinear Dynamics
9.
Arch Microbiol ; 200(5): 803-810, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29428982

ABSTRACT

Burkholderia anthina XXVI is a rhizosphere bacterium isolated from a mango orchard in Mexico. This strain has a significant biological control activity against the causal agent of mango anthracnose, Colletotrichum gloeosporioides, likely through the production of siderophores and other secondary metabolites. Here, we present a draft genome sequence of B. anthina XXVI (approximately 7.7 Mb; and G + C content of 67.0%), with the aim of gaining insight into the genomic basis of antifungal modes of action, ecological success as a biological control agent, and full biosynthetic potential.


Subject(s)
Burkholderia/genetics , Antibiosis , Base Sequence , Biological Control Agents , Biosynthetic Pathways , Burkholderia/isolation & purification , Molecular Sequence Annotation , Multigene Family , Phylogeny , Whole Genome Sequencing
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 3489-3492, 2017 Jul.
Article in English | MEDLINE | ID: mdl-29060649

ABSTRACT

In this work, a nonlinear method to study multivariate interactions, called multivariate symbolic dynamics (MSD), was introduced. The usefulness of this technique was studied on respiratory-cardiovascular data from young women with vasovagal syncope (VVS) and from healthy subjects. The study included 16 female patients diagnosed with VVS and 24 age-matched healthy subjects (12 women). All subjects were enrolled in a head-up tilt (HUT) test, breathing normally, including 5 min of supine position and 18 to 28 min of 70° orthostatic phase. The MSD parameters were dynamically obtained for 5-min windows shifted by 1 min during HUT test. In supine position there were no considerable differences. During orthostatic phase, parameters from MSD showed a highly significantly (p=0.00005) increased occurrence of impaired respiratory-cardiovascular interactions in female patients susceptible to vasovagal syncope. This study provided promising results for a new multivariate method to investigate respiratory-cardiovascular interactions.


Subject(s)
Cardiovascular System , Female , Humans , Posture , Respiration , Syncope, Vasovagal , Tilt-Table Test
11.
Rev. chil. obstet. ginecol. (En línea) ; 82(4): 466-468, oct. 2017.
Article in Spanish | LILACS | ID: biblio-899930

ABSTRACT

Se presenta el caso de una mujer de 38 años con Síndrome de Marshall-Smith. Se trata de una enfermedad rara de etiología desconocida, cuyas características incluyen anomalías craneofaciales, maduración ósea acelerada, alteraciones en el desarrollo neurológico y en las vías respiratorias con compromiso de la vía aérea y escasa supervivencia a largo plazo debido a problemas respiratorios. Sin embargo, los avances en el soporte respiratorio han permitido que algunos pacientes lleguen a la etapa adulta. Nuestra paciente, sin retraso intelectual ni psicomotor, solicita método anticonceptivo. Los pacientes con enfermedades raras necesitan ser atendidos con especial dedicación intentando reducir al mínimo la transmisión genética de dichas entidades, y mejorando al máximo su calidad de vida. Se ofrece un método anticonceptivo reversible de larga duración, sin riesgos para la evolución de su patología respiratoria, y atendiendo a los criterios medicos de elegibilidad de método anticonceptivo de la OMS, se indica la utilización de un implante subdérmico de etonogestrel. Con un perfil de seguridad y farmacocinética equivalente a los métodos de solo gestágeno y mayor comodidad.


A 38-year-old female patient with a history of Marshall-Smith syndrome is reported. It is a rare congenital disorder of unknown aetiology, which features include craneo facial dysmorphism, accelerated bone maturation, neurodevelopmental abnormalities, and upper and lower airways compromise. Long term survival is a problem due to respiratory complications, but it has decreased since airway support has improved, and that allows survival into adulthood. Our patient has neither intelectual nor psychomotor delay, so she asks for contraception method. As a rare genetic condition it needs to be attended with special consideration in order to reduce the disorder's transmission and to increase the life's quality of patients. A secure contraception method should be offered with no risk at all, attending to medical elegibility criteria for contraception use. We considered progestogen-only options and the patient's choice was etonogestrel subcutaneous implant.


Subject(s)
Humans , Female , Adult , Abnormalities, Multiple/therapy , Long-Acting Reversible Contraception/methods , Syndrome
12.
Rev. mex. ing. bioméd ; 38(1): 155-165, ene.-abr. 2017. tab, graf
Article in Spanish | LILACS-Express | LILACS | ID: biblio-902334

ABSTRACT

Resumen: En este trabajo se presenta un método para calcular los niveles de fibrosis pulmonar en imágenes de tomografía axial computarizada. Se utilizó un algoritmo de segmentación semiautomática basado en el método de Chan-Vese. El método mostró similitudes de forma cualitativa en la región de la fibrosis con respecto al experto clínico. Sin embargo es necesario validar los resultados con una base de datos mayor. El método propuesto aproxima un porcentaje de fibrosis de forma fácil para apoyar su implementación en la práctica clínica minimizando la subjetividad del experto médico y generando una estimación cuantitativa de la región de fibrosis.


Abstract: A method to estimate the pulmonary fibrosis in computed tomography (CT) imaging is presented. A semi-automatic segmentation algorithm based on the Chan-Vese method was used. The proposed method shows a similar fibrosis región with respect to clinical expert. However, the results need to be validated in a bigger data base. The proposed method approximates a fibrosis percentage that allows to achieve this procedure easily in order to support its implementation in the clinical practice minimizing the clinical expert subjectivity and generating a quantitative estimation of fibrosis region.

13.
Physiol Meas ; 37(3): 314-32, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26849375

ABSTRACT

In studies of autonomic regulation during orthostatic challenges only a few nonlinear methods have been considered without investigating the effect of gender in young controls. Especially, the temporal development of the autonomic regulation has not yet been explicitly analyzed using short-term segments in supine position, transition and orthostatic phase (OP). In this study, nonlinear analysis of cardiovascular and respiratory time series was performed to investigate how nonlinear indices are dynamically changing with respect to gender during orthostatic challenges. The analysis was carried out using shifted short-term segments throughout a head-up tilt test in 24 healthy subjects, 12 men (26 ± 4 years) and 12 age-matched women (26 ± 5 years), at supine position and during OP at 70°. The nonlinear methods demonstrated statistical differences in the autonomic regulation between males and females. Orthostatic stress caused significantly decreased heart rate variability due to increased sympathetic activity mainly in men, already at the beginning and during the complete OP, revealed by (a) increased occurrence of specific word types with constant fluctuations as pW111 from symbolic dynamics, (b) augmented fractal correlation properties by the short-term index alpha1 from detrended fluctuation analysis, (c) increased slope indices (21ati and 31ati) from auto-transinformation and (d) augmented time irreversibility indices demonstrating more temporal asymmetries and nonlinear dynamics in men than in women. After tilt-up, both men and women increased their sympathetic activity but in a different way. Time-dependent gender differences during orthostatic challenge were shown directly between men and women or indirectly comparing baseline and different temporal stages of OP. The proposed dynamical study of autonomic regulation has the advantage of screening the fluctuations of the sympathetic and vagal activities that can be quantified by the temporal behavior of nonlinear indices. The findings in this paper strongly suggest the need for gender separation in studies of the dynamics of autonomic regulation during orthostatic challenge.


Subject(s)
Autonomic Nervous System/physiology , Sex Characteristics , Tilt-Table Test , Adult , Algorithms , Entropy , Female , Heart Rate/physiology , Hemodynamics , Humans , Male , Nonlinear Dynamics
14.
Comput Methods Programs Biomed ; 127: 185-96, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26775735

ABSTRACT

The cardiovascular and respiratory autonomic nervous regulation has been studied mainly by hemodynamic responses during different physical stressors. In this study, dynamics of autonomic response to an orthostatic challenge was investigated by hemodynamic variables and by diverse linear and nonlinear indices calculated from time series of beat-to-beat intervals (BBI), respiratory cycle duration (RESP), systolic (SYS) and diastolic (DIA) blood pressure. This study included 16 young female patients (SYN) with vasovagal syncope and 12 age-matched female controls (CON). The subjects were enrolled in a head-up tilt (HUT) test, breathing normally, including 5min of baseline (BL, supine position) and 18min of 70° orthostatic phase (OP). To increase the time resolution of the analysis the time series were segmented in five-minute overlapping windows with a shift of 1min. Hemodynamic parameters did not show any statistical differences between SYN and CON. Time domain linear analysis revealed increased respiratory frequency and increased blood pressure variability (BPV) in patients during OP meaning increased sympathetic activity and vagal withdrawal. Frequency domain analysis confirmed a predominance of sympathetic tone by steadily increased values of low over high frequency power in BBI and of low frequency power in SYS and DIA in patients during OP. The nonlinear analysis by symbolic dynamics seemed to be highly suitable for differentiation of SYN and CON in the early beginning of OP, i.e., 5min after tilt-up. In particular the index SYS_plvar3 showed less patterns of low variability in patients reflecting a steadily increase in both BPV and sympathetic activity. The proposed dynamical analysis could lead to a better understanding of the temporal underlying mechanisms in healthy subjects and patients under orthostatic stress.


Subject(s)
Posture , Syncope, Vasovagal/etiology , Adult , Case-Control Studies , Female , Humans , Linear Models , Young Adult
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 684-687, 2016 Aug.
Article in English | MEDLINE | ID: mdl-28268420

ABSTRACT

In this work, a graphical method to study cardiovascular coupling, called delta space plot analysis (DSPA), was introduced. The graphical representation is susceptible to be parameterized in shape and orientation. The usefulness of this technique was studied on cardiovascular data from patients with vasovagal syncope (VVS) and from controls. The study included 15 female patients diagnosed with VVS and 11 age-matched healthy female subjects. All subjects were enrolled in a head-up tilt (HUT) test, breathing normally, including 5 minutes of supine position (baseline) and 18 minutes of 70° orthostatic phase. The DSPA parameters were obtained at different times during the HUT test, i.e., at baseline, early (first 5 min) and late (10-15 min) orthostatic phases. In baseline there were no considerable differences between female controls and female patients. During the late orthostatic phase, parameters from DSPA showed highly significantly (p=0.000003) reduced cardiovascular coupling in patients. Findings indicated a loss of control on cardiovascular coupling in female patients susceptible to vasovagal syncope during orthostatic challenge. In addition, this study provided promising results for a new graphical method to investigate cardiovascular coupling.


Subject(s)
Syncope, Vasovagal/diagnosis , Adult , Blood Pressure/physiology , Cardiovascular System/diagnostic imaging , Case-Control Studies , Electrocardiography , Female , Heart Rate/physiology , Humans , Tilt-Table Test , Young Adult
16.
Rev. méd. Chile ; 143(6): 759-766, jun. 2015. ilus, tab
Article in Spanish | LILACS | ID: lil-753516

ABSTRACT

Surgical resection of lung cancer, the only available curative option today, is strongly associated with mortality. The goal during the perioperative period is to identify and evaluate appropriate candidates for lung resection in a more careful way and reduce the immediate perioperative risk and posterior disability. This is a narrative review of perioperative risk assessment in lung cancer resection. Instruments designed to facilitate decision-making have been implemented in recent years but with contradictory results. Cardiovascular risk assessment should be the first step before a potential lung resection, considering that most of these patients are old, smokers and have atherosclerosis. Respiratory mechanics determined by postoperative forced expiratory volume in the first second (FEV1), the evaluation of the alveolar-capillary membrane by diffusing capacity of carbon monoxide and cardiopulmonary function measuring the maximum O2 consumption, will give clues about the patient s respiratory and cardiac response to stress. With these assessments, the patient and its attending team can reach a treatment decision balancing the perioperative risk, the chances of survival and the pulmonary long-term disability.


Subject(s)
Humans , Lung Neoplasms/mortality , Postoperative Complications/prevention & control , Preoperative Care , Lung Neoplasms/surgery , Oxygen Consumption , Predictive Value of Tests , Respiratory Function Tests , Risk Factors
17.
Article in English | MEDLINE | ID: mdl-26736694

ABSTRACT

The gradual shift of cardiac autonomic regulation toward sympathetic predominance and vagal withdrawal during graded head-up tilt test in young controls has been demonstrated by parameters from symbolic dynamics obtained from short-term heart rate variability (HRV) analysis. In this study, the influence of gender and vasovagal syncope (VVS) on the autonomic response to an orthostatic challenge was investigated by HRV analysis using short-term symbolic dynamics (STSD). This study included 24 healthy young subjects (12 males; 12 age-matched females) and 16 female patients diagnosed with VVS. All subjects were enrolled in a head-up tilt (HUT) test, breathing normally, including 5 minutes of supine position (baseline) and 20-40 minutes of 70° orthostatic phase. The STSD parameters were obtained following their behavior at different times during the HUT test, i.e., at baseline, early and middle orthostatic phases. Gender differences including increased sympathetic activity in men were already present in baseline and in the middle tilt phase. In baseline there were no differences between female controls and female patients, but parameters from STSD showed highly significantly (p=0.0007) reduced heart rate variability due to increased sympathetic activity in female patients in the middle tilt phase. Furthermore a new nonlinear index for the estimation of sympatho-vagal balance was introduced.


Subject(s)
Autonomic Nervous System/physiopathology , Dizziness/physiopathology , Heart/physiopathology , Adult , Case-Control Studies , Female , Healthy Volunteers , Heart Rate/physiology , Humans , Male , Sex Characteristics , Syncope, Vasovagal/physiopathology , Tilt-Table Test , Time Factors
18.
Comput Methods Programs Biomed ; 114(3): 276-90, 2014 May.
Article in English | MEDLINE | ID: mdl-24680639

ABSTRACT

A step forward in the knowledge about the underlying physiological phenomena of thoracic sounds requires a reliable estimate of their time-frequency behavior that overcomes the disadvantages of the conventional spectrogram. A more detailed time-frequency representation could lead to a better feature extraction for diseases classification and stratification purposes, among others. In this respect, the aim of this study was to look for an omnibus technique to obtain the time-frequency representation (TFR) of thoracic sounds by comparing generic goodness-of-fit criteria in different simulated thoracic sounds scenarios. The performance of ten TFRs for heart, normal tracheal and adventitious lung sounds was assessed using time-frequency patterns obtained by mathematical functions of the thoracic sounds. To find the best TFR performance measures, such as the 2D local (ρ(mean)) and global (ρ) central correlation, the normalized root-mean-square error (NRMSE), the cross-correlation coefficient (ρ(IF)) and the time-frequency resolution (res(TF)) were used. Simulation results pointed out that the Hilbert-Huang spectrum (HHS) had a superior performance as compared with other techniques and then, it can be considered as a reliable TFR for thoracic sounds. Furthermore, the goodness of HHS was assessed using noisy simulated signals. Additionally, HHS was applied to first and second heart sounds taken from a young healthy male subject, to tracheal sound from a middle-age healthy male subject, and to abnormal lung sounds acquired from a male patient with diffuse interstitial pneumonia. It is expected that the results of this research could be used to obtain a better signature of thoracic sounds for pattern recognition purpose, among other tasks.


Subject(s)
Heart Sounds , Respiratory Sounds , Algorithms , Computer Simulation , Humans , Male , Middle Aged , Models, Theoretical , Reproducibility of Results , Signal Processing, Computer-Assisted , Software , Sound Spectrography/methods , Time Factors , Trachea/physiology
19.
Comput Biol Med ; 45: 58-66, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24480164

ABSTRACT

Multichannel analysis of lung sounds (LSs) has enabled the generation of a functional image for the temporal and spatial study of LS intensities in healthy and diseased subjects; this method is known as respiratory acoustic thoracic imaging (RATHI). This acoustic imaging technique has been applied to diverse pulmonary conditions, but it is important to contribute to the understanding of RATHI characteristics, such as acoustic spatial distribution, dependence on airflow and variability. The purpose of the current study is to assess the intra-subject and inter-subject RATHI variabilities in a cohort of 12 healthy male subjects (24.3±1.5 years) using diverse quantitative indices. The indices were obtained directly from the acoustic image and did not require scores from human raters, which helps to prevent inter-observer variability. To generate the acoustic image, LSs were acquired at 25 positions on the posterior thoracic surface by means of airborne sound sensors with a wide frequency band from 75 up to 1000 Hz under controlled airflow conditions at 1.0, 1.5 and 2.0 L/s. To assess intra-subject variability, the degree of similitude between inspiratory acoustic images was evaluated through quadratic mutual information based on the Cauchy-Schwartz inequality (I(CS)). The inter-subject variability was assessed by an image registration procedure between RATHIs and X-ray images to allow the computation of average and variance acoustic image in the same coordinate space. The results indicated that intra-subject RATHI similitude, reflected by I(CS-global), averaged 0.960±0.008, 0.958±0.008 and 0.960±0.007 for airflows of 1.0, 1.5, and 2L/s, respectively. As for the inter-subject variability, the variance image values for three airflow conditions indicated low image variability as they ranged from 0.01 to 0.04. In conclusion, the assessment of intra-subject and inter-subject variability by similitude indices indicated that the acoustic image pattern is repeatable along different respiratory cycles and across different subjects. Therefore, RATHI could be used to explore different aspects of spatial distribution and its association with regional pulmonary ventilation.


Subject(s)
Image Processing, Computer-Assisted/methods , Respiratory Sounds/physiology , Signal Processing, Computer-Assisted , Sound Spectrography/instrumentation , Sound Spectrography/methods , Adult , Humans , Male , Radiography, Thoracic , Reproducibility of Results , Young Adult
20.
Article in English | MEDLINE | ID: mdl-25570721

ABSTRACT

Gender related-differences in the autonomic regulation of the cardiovascular and cardiorespiratory systems have been studied mainly by hemodynamic responses during different physical stressors. In this study, the influence of gender on the autonomic response to an orthostatic challenge was investigated by obtaining the cardiovascular and cardiorespiratory coupling using the nonlinear technique known as joint symbolic dynamics (JSD) representation. This study includes 24 healthy young subjects. Males (N=12) and age-matched females (N=12) were enrolled in a head-up tilt (HUT) test, breathing normally, including 5 minutes of supine position (baseline) and 25-40 minutes of 70° orthostatic phase. The cardiovascular and cardiorespiratory couplings were obtained at baseline, early and middle orthostatic phases. Although in baseline there were some gender differences, parameters from JSD showed highly significant (p=0.0004) differences in specific cardiovascular coupling patterns in the early tilt phase. Furthermore, JSD analysis revealed that in males, due to increased sympathetic activity, exist a lower degree of cardiovascular coupling accompanied with an increased occurrence of tachycardic patterns. On the other hand, the cardiorespiratory coupling revealed only very few slightly significant differences in all three phases.


Subject(s)
Algorithms , Healthy Volunteers , Heart/physiology , Respiration , Sex Characteristics , Tilt-Table Test , Adult , Female , Humans , Male
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