Assessing the effects of oxytocin in changes of core body temperature during LPS-induced endotoxemia: A novel approach using Extended Poincaré Plot Analysis.

Oxytocin has shown cardioprotective effects during inflammation and may modify the core body temperature changes in LPS-induced endotoxemia. Notably, the time series analysis of core body temperature fluctuations may indicate thermoregulation alterations. This study aims to assess the effects of oxytocin on changes in the core body temperature by analyzing the fluctuations of the temperature time series of endotoxemic rats. Twelve hours of continuous core body temperature fluctuations time series were obtained from adult male Dark Agouti rats implanted with a telemetric transmitter under the following treatment: lipopolysaccharide (LPS); oxytocin (O); lipopolysaccharide + oxytocin (LPS + O), and vehicle or control (C). The temperature fluctuations time series were analyzed using the Extended Poincaré Plot Analysis (EPPA), a novel approach for measuring nonlinear features, to compute the autocorrelation by Pearson's correlation coefficient r, the standard deviation perpendicular to the line of identity (SD1), and the standard deviation parallel to the line of identity (SD2). The autocorrelation of the temperature fluctuations assessed by Pearson's coefficient was significantly higher in the LPS group compared to control rats (C). Likewise, the co-administration of oxytocin during endotoxemia (LPS + O) significantly reduced the autocorrelation and increased the short-term variability (SD1) of temperature fluctuations compared to those recorded with a single dose of LPS. Thus, we concluded that oxytocin may introduce thermoregulatory changes under LPS-induced endotoxemia. The EPPA is a simple and powerful approach to assess physiological variability that can provide valuable insights into changes in thermoregulation.

Multiscale asymmetry reveals changes in the maternal short-term heart rate dynamics of preeclamptic women during labor.

BACKGROUND: It is known that acceleration and deceleration patterns in heart rate variability (HRV) are asymmetrically distributed in healthy subjects. Accordingly, novel approaches for assessing the asymmetrical properties of HRV, such as the multiscale asymmetry (MSA), have been applied in the perinatal field. OBJECTIVE: To study the asymmetry of accelerations and decelerations of maternal short-term cardiac dynamics of thirty-six normotensive and preeclamptic women during labor/nonlabor by MSA analysis. METHODS: The RR interval time series obtained from these participants were classified into four groups: normotensive (control) without labor C-NL, n= 10; control with labor C-L, n= 10; and two preeclamptic groups with absence or presence of labor P-NL, n= 6; and P-L, n= 10, respectively. Multiscale indices of heart rate asymmetry (HRA) such as Porta (P%), Guzik (G%) and Ehlers (E) were used to explore the changes of HRA in the normotensive and preeclamptic groups in the presence or absence of labor. RESULTS: The main result of this study shows that preeclamptic women manifest decreased magnitude of decelerations of heart rate dynamics compared to normotensive women indicated by G% and E. We speculate that a lower cardiac parasympathetic response may be manifested in preeclamptic women during labor/nonlabor compared to normotensive women. CONCLUSIONS: These observations represented a new insight into the autonomic cardiovascular regulation in preeclampsia, which could contribute to the perinatal field in the future.

Association of the Heart Rate Variability Response to Active Standing with the Severity of Calcific Aortic Valve Disease: Novel Insights of a Neurocardiovascular Pathology.

The aim of this work was to obtain insights of the participation of the autonomic nervous system in different stages of calcific aortic valve disease (CAVD) by heart rate variability (HRV) analysis. Studying subjects with no valve impairments and CAVD patients, we also sought to quantify the independent contribution or explanatory capacity of the aortic valve echocardiographic parameters involved in the HRV changes caused by active standing using hierarchical partitioning models to consider other variables or potential confounders. We detected smaller adjustments of the cardiac autonomic response at active standing caused specifically by the aortic valve deterioration. The highest association (i.e., the highest percentage of independent exploratory capacity) was found between the aortic valve area and the active standing changes in the short-term HRV scaling exponent α1 (4.591%). The valve's maximum pressure gradient echocardiographic parameter was present in most models assessed (in six out of eight models of HRV indices that included a valve parameter as an independent variable). Overall, our study provides insights with a wider perspective to explore and consider CAVD as a neurocardiovascular pathology. This pathology involves autonomic-driven compensatory mechanisms that seem generated by the aortic valve deterioration.

[Systematization of a comprehensive intervention for strengthening the COVID-19 medical care]. / Sistematización de una intervención gerencial integral para fortalecer la atención médica por COVID-19.

The COVID-19 pandemic established a new challenge for health services in Mexico, which is why these services faced the challenge of responding to the affected people, by providing them services with opportunity, efficiency, effectiveness and safety. The Instituto Mexicano del Seguro Social (IMSS, Mexican Institute for Social Security) gave medical attention to the larger number of affected people: towards the end of September, 2022, 3,335,552 patients were registered, who represented 47% of the total (7,089,209) of confirmed COVID-19 cases since the beginning of the pandemic in 2020. Of all the cases treated, 295,065 (8.8%) required hospitalization. In addition of new scientific evidence and the implementation of best practices in medical care and directive management (with the general objective of improvement of the processes in hospital attention, even without an effective treatment at the time), we presented an evaluation, supervision method with a comprehensive (involving the three levels of health services) and analytic (structure, process, result and directive management components) approach. The achievement of specific goals and lines of action was established in a technical guideline with health policies for the COVID-19 medical care. These guidelines were instrumented with a standardized evaluation tool, a result dashboard and a risk assessment calculator, improving the quality of medical care and directive management by the multidisciplinary health team.

La pandemia por COVID-19 puso a prueba la prestación de servicios de los sistemas de salud en México, por lo que estos enfrentaron el reto de responder a la necesidad de las personas afectadas al otorgar servicios oportunos, eficientes, eficaces y seguros. El Instituto Mexicano del Seguro Social (IMSS) atendió el mayor número de personas afectadas: al cierre de septiembre del 2022, se registraron 3,335,552 pacientes atendidos, quienes representaron 47% del total (7,089,209) de casos confirmados desde el inicio de la pandemia en 2020. De los casos notificados por el IMSS, 295,065 (8.8%) requirieron hospitalización. Mediante un atento seguimiento de la evolución de la evidencia científica (que permitió identificar y adoptar las mejores prácticas de atención médica y gestión directiva para fortalecer los procesos sustantivos en la atención hospitalaria, aun sin un tratamiento eficaz), se integró un método de evaluación, supervisión y asesoría, con enfoque integral (que involucró los tres niveles de atención médica) y analítico (componentes de estructura, proceso, resultado y gestión directiva). Los objetivos de la atención y las líneas de acción se describieron en una guía técnica que estableció las políticas de atención médica al COVID-19. Asimismo, fue instrumentado con una cédula de evaluación estandarizada, un tablero de control de resultados y una herramienta de estratificación del riesgo. Con ello se mejoró la calidad de atención por medio de la participación del personal directivo y de equipos multidisciplinarios de salud, los cuales permitieron la toma de decisiones clínicas y gerenciales.

Differences in the Asymmetry of Beat-to-Beat Fetal Heart Rate Accelerations and Decelerations at Preterm and Term Active Labor.

The fetal autonomic nervous system responds to uterine contractions during active labor as identified by changes in the accelerations and decelerations of fetal heart rate (FHR). Thus, this exploratory study aimed to characterize the asymmetry differences of beat-to-beat FHR accelerations and decelerations in preterm and term fetuses during active labor. In an observational study, we analyzed 10 min of fetal R-R series collected from women during active preterm labor (32-36 weeks of pregnancy, n = 17) and active term labor (38-40 weeks of pregnancy, n = 27). These data were used to calculate the Deceleration Reserve (DR), which is a novel parameter that quantifies the asymmetry of the average acceleration and deceleration capacity of the heart. In addition, relevant multiscale asymmetric indices of FHR were also computed. Lower values of DR, calculated with the input parameters of T = 50 and s = 10, were associated with labor occurring at the preterm condition (p = 0.0131). Multiscale asymmetry indices also confirmed significant (p < 0.05) differences in the asymmetry of FHR. Fetuses during moderate premature labor may experience more decaying R-R trends and a lower magnitude of decelerations compared to term fetuses. These differences of FHR dynamics might be related to the immaturity of the fetal cardiac autonomic nervous system as identified by this system response to the intense uterine activity at active labor.

A Translational Perspective of Maternal Immune Activation by SARS-CoV-2 on the Potential Prenatal Origin of Neurodevelopmental Disorders: The Role of the Cholinergic Anti-inflammatory Pathway.

The emergent Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) could produce a maternal immune activation (MIA) via the inflammatory response during gestation that may impair fetal neurodevelopment and lead to postnatal and adulthood mental illness and behavioral dysfunctions. However, so far, limited evidence exists regarding long-term physiological, immunological, and neurodevelopmental modifications produced by the SARS-CoV-2 in the human maternal-fetal binomial and, particularly, in the offspring. Relevant findings derived from epidemiological and preclinical models show that a MIA is indeed linked to an increased risk of neurodevelopmental disorders in the offspring. We hypothesize that a gestational infection triggered by SARS-CoV-2 increases the risks leading to neurodevelopmental disorders of the newborn, which can affect childhood and the long-term quality of life. In particular, disruption of either the maternal or the fetal cholinergic anti-inflammatory pathway (CAP) could cause or exacerbate the severity of COVID-19 in the maternal-fetal binomial. From a translational perspective, in this paper, we discuss the possible manifestation of a MIA by SARS-CoV-2 and the subsequent neurodevelopmental disorders considering the role of the fetal-maternal cytokine cross-talk and the CAP. Specifically, we highlight the urgent need of preclinical studies as well as multicenter and international databanks of maternal-fetal psychophysiological data obtained pre-, during, and post-infection by SARS-CoV-2 from pregnant women and their offspring.

Phase Entropy Analysis of Electrohysterographic Data at the Third Trimester of Human Pregnancy and Active Parturition.

Phase Entropy (PhEn) was recently introduced for evaluating the nonlinear features of physiological time series. PhEn has been demonstrated to be a robust approach in comparison to other entropy-based methods to achieve this goal. In this context, the present study aimed to analyze the nonlinear features of raw electrohysterogram (EHG) time series collected from women at the third trimester of pregnancy (TT) and later during term active parturition (P) by PhEn. We collected 10-min longitudinal transabdominal recordings of 24 low-risk pregnant women at TT (from 35 to 38 weeks of pregnancy) and P (>39 weeks of pregnancy). We computed the second-order difference plots (SODPs) for the TT and P stages, and we evaluated the PhEn by modifying the k value, a coarse-graining parameter. Our results pointed out that PhEn in TT is characterized by a higher likelihood of manifesting nonlinear dynamics compared to the P condition. However, both conditions maintain percentages of nonlinear series higher than 66%. We conclude that the nonlinear features appear to be retained for both stages of pregnancy despite the uterine and cervical reorganization process that occurs in the transition from the third trimester to parturition.

Analysis of the fetal cardio-electrohysterographic coupling at the third trimester of gestation in healthy women by Bivariate Phase-Rectified Signal Averaging.

INTRODUCTION: The fetal cardio-electrohysterographic coupling (FCEC) is defined as the influence of the uterine electrical activity on fetal heart rate. FCEC has been mainly evaluated by visual analysis of cardiotocographic data during labor; however, this physiological phenomenon is poorly explored during the antenatal period. Here we propose an approach known as Bivariate Phase-Rectified Signal Averaging analysis (BPRSA) to assess such FCEC in the late third trimester of low-risk pregnancies. We hypothesized that BPRSA is a more reliable measure of FCEC than visual analysis and conventional measures such as cross-correlation, coherence, and cross-sample entropy. Additionally, by using BPRSA it is possible to detect FCEC even from the third trimester of pregnancy. MATERIAL AND METHODS: Healthy pregnant women in the last third trimester of pregnancy (36.6 ± 1.8 gestational weeks) without any clinical manifestation of labor were enrolled in the Maternal and Childhood Research Center (CIMIGen), Mexico City (n = 37). Ten minutes of maternal electrohysterogram (EHG) and fetal heart rate (FHR) data were collected by a transabdominal non-invasive device. The FCEC was quantified by the coefficient of coherence, the maximum normalized cross-correlation, and the cross-sample entropy obtained either from the EHG and FHR raw signals or from the corresponding BPRSA graphs. RESULTS: We found that by using BPRSA, the FCEC was detected in 92% cases (34/37) compared to 48% cases (18/37) using the coefficient of coherence between the EHG and FHR raw signals. Also, BPRSA indicated FCEC in 82% cases (30/37) compared to 30% cases (11/37) using the maximum normalized cross-correlation. By comparing the analyses, the BPRSA evidenced higher FCEC in comparison to the coupling estimated from the raw EHG and FHR signals. CONCLUSIONS: Our results support the consideration that in the third trimester of pregnancy, the fetal heart rate is also influenced by uterine activity despite the emerging manifestation of this activity before labor. To quantify FCEC, the BPRSA can be applied to FHR and EHG transabdominal signals acquired in the third trimester of pregnancy.

Comparison of fetal heart rate variability by symbolic dynamics at the third trimester of pregnancy and low-risk parturition.

Fetal heart rate variability (fHRV) is an essential source of information to monitor fetal well-being during pregnancy. This study aimed to apply a nonlinear approach, known as symbolic dynamics (SD), for comparing human fHRV in the third trimester of pregnancy during active fetal state (TT) and active labor at term (P). We performed a longitudinal, prospective, descriptive, and comparative study composed of 42 longitudinal recordings of 5-minutes of fetal heartbeat interval series. Recordings were collected from 21 low-risk, healthy, pregnant women attending the Maternal and Child Research Center (CIMIGen), Mexico City. We calculated relevant linear parameters of fHRV between TT and P stages, such as the percentage of differences between adjacent RR intervals >5 ms (PRR5, related to vagal modulations) and other SD parameters such as the percentage of no variations between three successive symbols (%0V, reflects sympathetic modulations) and the probability of low variability with a threshold of 4 ms (POLVAR4, associated with a low variability). We identified statistical differences for PRR5 between TT and P (37.13% [28.47-47.60%] vs. 28.84% [19.36-36.76%], p = 0.03), respectively. Also, for 0V% (65.66% [59.01-71.80%] vs. 71.14% [65.94-75.87%], p = 0.03) and for POLVAR4 values (0.06 [0.04-0.11] vs. 0.15 [0.09-0.24], p = 0.002), respectively. Our results indicate that during parturition, the short-term fetal fHRV is decreased, showing a decreased vagal modulations and higher adrenergic response of the heart. These autonomic modifications may result from the fetal response to the stressful inflammatory challenge of labor. We thus confirmed that the analysis of the SD applied to fHRV time series could be a potential clinical biomarker to differentiate the fetal autonomic cardiac condition at different stages of pregnancy.

Neuroautonomic activity evidences parturition as a complex and integrated neuro-immune-endocrine process.

Parturition in mammals demands a precise coordination of several neuro-immune-endocrine interactions including: a sterile inflammatory response that involves secretion of inflammation mediators like cytokines/chemokines; changes in the secretion of hormones such as progestogen, estrogens, cortisol, and oxytocin; as well as adjustments of the neuroautonomic function. Specifically, the so-called cholinergic anti-inflammatory pathway seems to play a key role in the homeostasis of the neuro-immune-endocrine axis by adjusting the vagus nerve activity during parturition. Here, we provide insights into the importance of the vagus during parturition from an autonomic, endocrine, and immune interplay perspective, and describe the potential role of heart rate variability analysis to explore these interactions noninvasively, economically, and accessibly.

[Evacuation of critical care areas due to an initial outbreak of fire in a second level hospital]. / Evacuación de áreas críticas por conato de incendio en un hospital de segundo nivel.

In this letter to the editor, it is exposed an initial outbreak of fire that affected a secondary care center in Córdova, Veracruz, Mexico, and, most of all, the lack of a hospital fire evacuation plan in the presence of a fire event.

En la presente carta al editor, se expone un conato de incendio ocurrido en un hospital de segundo nivel de atención en Córdova, Veracruz, México, y, sobre todo, la carencia de un plan hospitalario de evacuación ante un evento de este tipo.

[Hospitales del Instituto Mexicano del Seguro Social durante los sismos de septiembre de 2017. Análisis desde la perspectiva del Programa Hospital Seguro].

INTRODUCTION: The function of hospitals during major emergency or disaster is vital. Their response capacity depends on their geographic location, adequate organization, structural safety and safety of non-structural elements. After September 2017 earthquakes, self-assessment and Safe Hospital Program assessment results were compared in disabled hospitals belonging to the Mexican Institute of Social Security. OBJECTIVE: To compare the Hospital Safety Index (HIS) with self-assessments carried out by the units. METHOD: HIS and the Pan-American Health Organization/World Health Organization checklist were used. The comparison was carried out in 3 hospitals that were disabled after September 2017 earthquakes. RESULTS: Variability was observed in HIS, which revealed self-assessment biases: no hospital obtained a HIS score lower than 0.35, although all 3 were disabled in the immediate phase after the seismic events. CONCLUSIONS: Result variability depends on who applies the instrument. Quick HIS assessment provides an immediate idea of the probability for a hospital to continue functioning in case of disaster and allows determining mitigation actions to increase health facilities' resilience and safety.

INTRODUCCIÓN: La función de los hospitales durante una emergencia mayor o desastre es vital. Su capacidad de respuesta depende de su ubicación geográfica, adecuada organización, seguridad estructural y seguridad de elementos no estructurales. Después de los sismos de septiembre de 2017 se compararon los resultados de las autoevaluaciones y la evaluación del Programa Hospital Seguro en los hospitales inhabilitados pertenecientes al Instituto Mexicano del Seguro Social. OBJETIVO: Comparar el Índice de Seguridad Hospitalaria (ISH) contra las autoevaluaciones realizadas por las unidades. MÉTODO: Se utilizó el ISH y la Lista de Verificación de la Organización Panamericana de la Salud/Organización Mundial de la Salud. La comparación se realizó en tres hospitales inhabilitados posterior a los sismos de septiembre de 2017. RESULTADOS: Se observó variabilidad en los ISH, lo que evidenció sesgos en la autoevaluación: ningún hospital obtuvo una calificación inferior a 0.35 en su ISH aunque tres quedaron inhabilitados en la fase inmediata posterior a los eventos sísmicos. CONCLUSIONES: La variabilidad en los resultados depende de quien aplica el instrumento. La evaluación rápida con ISH proporciona una idea inmediata de la probabilidad de que un hospital continúe funcionando en caso de desastre y permite determinar las acciones de mitigación para incrementar la resiliencia y seguridad de las instalaciones de salud.

[The experience of a medical emergency team belonging to the Mexican Social Security Institute during the earthquake in Mexico in September 2017Experiência de uma equipe médica de emergência do IMSS no terremoto do México em setembro de 2017]. / Experiencia de un equipo médico de emergencia del IMSS durante el sismo en México en setiembre de 2017.

The objective of this article is to describe the actions undertaken by the emergency medical team (EMT) of the Mexican Social Security Institute (MSSI) during the emergency caused by the earthquake of September 7, 2017 (magnitude 8.2; epicenter 133 km southwest of Pijijiapan, Chiapas, Mexico). After the initial intersectoral assessment of the emergency had been conducted, the health sector stepped in. As part of this response effort, and once it was determined that a large number of people had been injured and that the health risks facing the affected population were substantial, the MSSI deployed an EMT equipped and trained to provide support in the medical and surgical treatment of injured people. The actions of the EMT, composed of specialists in medical and surgical emergencies and disaster situations, included providing medical care to 252 patients, managing the transfer of 57 patients, and helping to set up an emergency hospital. To improve response efforts during disaster situations, it is necessary to follow the process of forming, registering, and training EMTs at the national and international levels.

O propósito deste artigo é descrever as ações empreendidas pela equipe médica de emergência (EMT) do Instituto Mexicano de Seguro Social (IMSS, instituição pública que presta serviços de saúde) na crise de emergência causada pelo terremoto de 7 de setembro de 2017, com magnitude de 8,2 graus e epicentro a 133 km a sudoeste de Pijijiapan, Chiapas, México. Após a avaliação intersetorial inicial de emergência, o setor da saúde foi ativado. Como parte da resposta, diante do elevado número de feridos e alto risco para a saúde pública da população afetada, o IMSS mobilizou uma EMT na região, capacitada e treinada para dar apoio à resposta de atendimento médica e cirúrgica das vítimas. A EMT, formada por especialistas em emergências médico-cirúrgicas e desastres, prestou atendimento médico a 252 pacientes, coordenou a transferência de 57 pacientes e também colaborou na preparação de um hospital provisório. A fim de melhorar a resposta a desastres, é necessário prosseguir com o processo de integração, cadastramento e capacitação das EMT ao nível nacional e internacional.

Experiencia de un equipo médico de emergencia del IMSS durante el sismo en México en setiembre de 2017 / The experience of a medical emergency team belonging to the Mexican Social Security Institute during the earthquake in Mexico in September 2017 / Experiência de uma equipe médica de emergência do IMSS no terremoto do México em setembro de 2017

RESUMEN El objetivo de este trabajo es describir las acciones desarrolladas por el equipo médico de emergencia (EMT por sus siglas en inglés) del Instituto Mexicano del Seguro Social (IMSS) durante la emergencia derivada del sismo del 7 de setiembre de 2017, el cual tuvo una magnitud de 8,2 grados con epicentro a 133 km al suroeste de Pijijiapan, Chiapas, México. Una vez realizada la evaluación inicial intersectorial de la emergencia, se activó el sector salud. Dentro de esta respuesta, y una vez determinado un número elevado de lesionados y un riesgo alto para la salud pública de la población afectada, el IMSS desplegó en la región un EMT capacitado y entrenado para apoyar en la respuesta de atención médica y quirúrgica de lesionados. Las acciones del EMT, conformado por especialistas en urgencias médico-quirúrgicas y desastres, incluyeron la atención médica de 252 pacientes, la gestión del traslado de 57 pacientes y la colaboración en la habilitación de un hospital provisorio. Para mejorar la respuesta en situaciones de desastres, se requiere seguir el proceso de integración, registro y capacitación de los EMT a nivel nacional e internacional.(AU)

ABSTRACT The objective of this article is to describe the actions undertaken by the emergency medical team (EMT) of the Mexican Social Security Institute (MSSI) during the emergency caused by the earthquake of September 7, 2017 (magnitude 8.2; epicenter 133 km southwest of Pijijiapan, Chiapas, Mexico). After the initial intersectoral assessment of the emergency had been conducted, the health sector stepped in. As part of this response effort, and once it was determined that a large number of people had been injured and that the health risks facing the affected population were substantial, the MSSI deployed an EMT equipped and trained to provide support in the medical and surgical treatment of injured people. The actions of the EMT, composed of specialists in medical and surgical emergencies and disaster situations, included providing medical care to 252 patients, managing the transfer of 57 patients, and helping to set up an emergency hospital. To improve response efforts during disaster situations, it is necessary to follow the process of forming, registering, and training EMTs at the national and international levels.(AU)

RESUMO O propósito deste artigo é descrever as ações empreendidas pela equipe médica de emergência (EMT) do Instituto Mexicano de Seguro Social (IMSS, instituição pública que presta serviços de saúde) na crise de emergência causada pelo terremoto de 7 de setembro de 2017, com magnitude de 8,2 graus e epicentro a 133 km a sudoeste de Pijijiapan, Chiapas, México. Após a avaliação intersetorial inicial de emergência, o setor da saúde foi ativado. Como parte da resposta, diante do elevado número de feridos e alto risco para a saúde pública da população afetada, o IMSS mobilizou uma EMT na região, capacitada e treinada para dar apoio à resposta de atendimento médica e cirúrgica das vítimas. A EMT, formada por especialistas em emergências médico-cirúrgicas e desastres, prestou atendimento médico a 252 pacientes, coordenou a transferência de 57 pacientes e também colaborou na preparação de um hospital provisório. A fim de melhorar a resposta a desastres, é necessário prosseguir com o processo de integração, cadastramento e capacitação das EMT ao nível nacional e internacional.(AU)

Women Serum Concentrations of the IL-10 Family of Cytokines and IFN-γ Decrease from the Third Trimester of Pregnancy to Active Labor.

Labor is regarded as increased myometrial activity with a regular contractility pattern. At this final stage of pregnancy, myometrial quiescence is lost, accompanied by altered immune homeostasis. It is well known that the interleukin (IL)-10 family of cytokines modulates immunological responses mainly in epithelial cells, including the endometrium. To investigate their inflammatory profile during labor, we performed a longitudinal study in a group of healthy pregnant women (n = 20) with uncomplicated pregnancies in the third trimester of pregnancy and during active labor. Blood was sampled from pregnant women in the third trimester (gestational age 32-38 weeks, mean 36 ± 2 weeks) and during active labor (39-41 weeks of gestation, mean 40 ± 1 weeks). Serum levels of several cytokines were measured using multiplex immunoassays for both stages, indicating that the concentrations of IL-10, IL-20, IL-22, IL-28A, and interferon (IFN)-γ were significantly decreased during active labor in comparison with third-trimester levels (p < 0.05). Our analysis did not find significant correlations between IL-10, IL-20, IL-22, IL-28A, and IFN-γ levels and gestational age. However, our data suggest that the systemic downregulation of several members of the IL-10 family of cytokines plays an important role in the activation of myometrial smooth cells associated with uterine contractions during active labor. Downregulation of this IL-10 family of cytokines seems to coincide with the well-reported functional progesterone withdrawal during labor. Likewise, lower plasma IFN-γ concentrations may indicate a role for IFN-γ in active labor.

Relationship in Pacemaker Neurons Between the Long-Term Correlations of Membrane Voltage Fluctuations and the Corresponding Duration of the Inter-Spike Interval.

Several studies of the behavior in the voltage and frequency fluctuations of the neural electrical activity have been performed. Here, we explored the particular association between behavior of the voltage fluctuations in the inter-spike segment (VFIS) and the inter-spike intervals (ISI) of F1 pacemaker neurons from H. aspersa, by disturbing the intracellular calcium handling with cadmium and caffeine. The scaling exponent α of the VFIS, as provided by detrended fluctuations analysis, in conjunction with the corresponding duration of ISI to estimate the determination coefficient R 2 (48-50 intervals per neuron, N = 5) were all evaluated. The time-varying scaling exponent α(t) of VFIS was also studied (20 segments per neuron, N = 11). The R 2 obtained in control conditions was 0.683 ([0.647 0.776] lower and upper quartiles), 0.405 [0.381 0.495] by using cadmium, and 0.151 [0.118 0.222] with caffeine (P < 0.05). A non-uniform scaling exponent α(t) showing a profile throughout the duration of the VFIS was further identified. A significant reduction of long-term correlations by cadmium was confirmed in the first part of this profile (P = 0.0001), but no significant reductions were detected by using caffeine. Our findings endorse that the behavior of the VFIS appears associated to the activation of different populations of ionic channels, which establish the neural membrane potential and are mediated by the intracellular calcium handling. Thus, we provide evidence to consider that the behavior of the VFIS, as determined by the scaling exponent α, conveys insights into mechanisms regulating the excitability of pacemaker neurons.

Oxytocin's role on the cardiorespiratory activity of endotoxemic rats.

BACKGROUND: Recent findings concerning oxytocin indicate its anti-inflammatory, cardioprotective and parasympathetic modulating properties. In this study, we investigated the effects of systemically applied oxytocin on the cardiorespiratory activity in a rodent model of moderate endotoxemia. METHODS: Telemetrically recorded electrocardiogram (ECGs) from animals which received lipopolysaccharide (LPS); oxytocin (Ox); lipopolysaccharide+oxytocin (LPS+Ox), or vehicle (V) were analyzed using the ECG-derived respiration (EDR) technique to estimate the respiratory rate. The mean R-R interval and the spectral parameters of heart rate variability (HRV), such as the natural logarithm of the high frequency (lnHF) and low frequency (lnLF) components were also estimated up to 24h after treatment. RESULTS: The endotoxemic animals (LPS) showed an elevated respiratory rate as well as a reduced mean R-R interval, lnHF and lnLF components compared to controls (V) from +5 to +12h after the treatment. The administration of oxytocin significantly attenuated the hyperventilation produced by the LPS-induced endotoxemia (LPS+Ox) and restored the values of the mean R-R interval and such spectral parameters at different time points. CONCLUSIONS: Our results support the existence of a link among the respiratory, cardiovascular, and immune systems in which oxytocin seems to act as a potential cardioprotective peptide by favoring cardiac cholinergic autonomic coupling. As a result, oxytocin diminished animal's endotoxemic tachypnea and restored the cardiorespiratory interactions, which was indicated by the spectral components of HRV.

Exogenous oxytocin reduces signs of sickness behavior and modifies heart rate fluctuations of endotoxemic rats.

Besides the well-known roles of oxytocin on birth, maternal bonding, and lactation, recent evidence shows that this hypothalamic hormone possesses cardioprotective, anti-inflammatory and parasympathetic neuromodulation properties. In this study, we explore the heart rate fluctuations (HRF) in an endotoxemic rodent model that was accompanied by the administration of exogenous oxytocin. The assessment of HRF has been widely used as an indirect measure of the cardiac autonomic function. In this context, adult male Dark Agouti rats were equipped with a telemetric transmitter to continuously and remotely measure the electrocardiogram, temperature, and locomotion. In a between-subjects experimental design, rats received the following peripheral treatment: saline solution as a vehicle (V); lipopolysaccharide (LPS); oxytocin (Ox); lipopolysaccharide + oxytocin (LPS+Ox). Linear and non-linear parameters of HRF were estimated starting 3h before to 24h after treatments. Our results showed that exogenous oxytocin does not modify by itself the HRF of oxytocin-treated rats in comparison to vehicle-treated rats. However, in animals undergoing endotoxemia it: a) provokes a less anticorrelated pattern in HRF, b) decreased mean heart rate, c) moderated the magnitude and duration of the LPS-induced hyperthermia, and d) increased locomotion, up to 6h after the LPS injection. The less anticorrelated pattern in the HRF and decreased mean heart rate may reflect a cardiac pacemaker coupling with cholinergic influences mediated by oxytocin during LPS-induced endotoxemia. Finally, the anti-lethargic and long-term temperature moderating effects of the administration of oxytocin during endotoxemia could be a consequence of the systemic anti-inflammatory properties of oxytocin.

Fractal-like correlations of the fluctuating inter-spike membrane potential of a Helix aspersa pacemaker neuron.

We analyzed the voltage fluctuations of the membrane potential manifested along the inter-spike segment of a pacemaker neuron. Time series of intracellular inter-spike voltage fluctuations were obtained in the current-clamp configuration from the F1 neuron of 12 Helix aspersa specimens. To assess the dynamic or stochastic nature of the voltage fluctuations these series were analyzed by Detrended Fluctuation Analysis (DFA), providing the scaling exponent α. The median α result obtained for the inter-spike segments was 0.971 ([0.963, 0.995] lower and upper quartiles). Our results indicate a critical-like dynamic behavior in the inter-spike membrane potential that, far from being random, shows long-term correlations probably linked to the dynamics of the mechanisms involved in the regulation of the membrane potential, thereby endorsing the occurrence of critical-like phenomena at a single-neuron level.

Delays in the human heartbeat dynamics.

This paper explores the possibility of applying statistical nonlinear physics methods to elucidate the underlying mechanisms controlling the heart rate. In particular, the presence of delays in RR interval dynamics is studied by using a lagged detrended fluctuation analysis. The results indicate that patients with congestive heart failure (CHF) have a prolonged time delay in the baroreflex response. Some implications of large delays for the functioning of autonomic control in subjects with CHF are discussed.