Correlations between sewage sludge composting physicochemical parameters and emissions of greenhouse gases and ammonia: A statistical analysis.

Mitigating the environmental impact of composting by the reduction of greenhouse gases (N2O, CH4) and ammonia (NH3) emissions is a major challenge. To meet this challenge, the understanding of the relationships between composted substrates initial physicochemical parameters and gas emissions is essential. From a long-term perspective, it will allow to guide the recipe formulation of the initial mixture to be composted, with a view to reducing gas emissions during composting. This study gathered literature data targeting sewage sludge composting and performed statistical correlation analyses between cumulative gas emissions and the following parameters: sewage sludge, bulking agent and composted mixture initial physicochemical parameters (pH, dry matter, total carbon, total nitrogen, C/N), the dry mass ratio of sewage sludge to bulking agent and the duration of composting. The average values of cumulative emissions show a large variability: 1.37 ± 2.71 gC.kg initial mix DM-1, 0.13 ± 0.17 gN.kg initial mix DM-1 and 2.23 ± 2.79 gN.kg initial mix DM-1 for CH4, N2O and NH3 emissions respectively. Although the correlation analysis highlighted some significant interesting correlations between initial physicochemical parameters and gas emissions (p.value < 0.05), reliable multiparametric model could not fit the data, meaning that the actual literature data are not sufficient to explain most part of gas emissions. Among the most interesting relationships, the study showed that the dry matter of the composted mixture is negatively correlated to N2O emissions, while the ratio of sewage sludge to bulking agent and the duration of composting are positively correlated to N2O emissions. It was also shown that the pH of the bulking agent is positively correlated to NH3 emissions. Considering the large part of the emission variability that is not explained and the difficulty to link the correlation with their causality, it will be interesting to improve composting gas emissions knowledge in future research by analyzing free air space, bulking agent adsorption capacity and available and biodegradable organic matter. These parameters are of particular interest in solving the main problems associated with sewage sludge composting, namely porosity and nitrogen retention. This study also highlighted the necessity to extend the duration of the composting studies over 40 days in order to measure possible N2O late release and better identify parameters influencing N2O emissions.

A global observational analysis to understand changes in air quality during exceptionally low anthropogenic emission conditions.

This global study, which has been coordinated by the World Meteorological Organization Global Atmospheric Watch (WMO/GAW) programme, aims to understand the behaviour of key air pollutant species during the COVID-19 pandemic period of exceptionally low emissions across the globe. We investigated the effects of the differences in both emissions and regional and local meteorology in 2020 compared with the period 2015-2019. By adopting a globally consistent approach, this comprehensive observational analysis focuses on changes in air quality in and around cities across the globe for the following air pollutants PM2.5, PM10, PMC (coarse fraction of PM), NO2, SO2, NOx, CO, O3 and the total gaseous oxidant (OX = NO2 + O3) during the pre-lockdown, partial lockdown, full lockdown and two relaxation periods spanning from January to September 2020. The analysis is based on in situ ground-based air quality observations at over 540 traffic, background and rural stations, from 63 cities and covering 25 countries over seven geographical regions of the world. Anomalies in the air pollutant concentrations (increases or decreases during 2020 periods compared to equivalent 2015-2019 periods) were calculated and the possible effects of meteorological conditions were analysed by computing anomalies from ERA5 reanalyses and local observations for these periods. We observed a positive correlation between the reductions in NO2 and NOx concentrations and peoples' mobility for most cities. A correlation between PMC and mobility changes was also seen for some Asian and South American cities. A clear signal was not observed for other pollutants, suggesting that sources besides vehicular emissions also substantially contributed to the change in air quality. As a global and regional overview of the changes in ambient concentrations of key air quality species, we observed decreases of up to about 70% in mean NO2 and between 30% and 40% in mean PM2.5 concentrations over 2020 full lockdown compared to the same period in 2015-2019. However, PM2.5 exhibited complex signals, even within the same region, with increases in some Spanish cities, attributed mainly to the long-range transport of African dust and/or biomass burning (corroborated with the analysis of NO2/CO ratio). Some Chinese cities showed similar increases in PM2.5 during the lockdown periods, but in this case, it was likely due to secondary PM formation. Changes in O3 concentrations were highly heterogeneous, with no overall change or small increases (as in the case of Europe), and positive anomalies of 25% and 30% in East Asia and South America, respectively, with Colombia showing the largest positive anomaly of ~70%. The SO2 anomalies were negative for 2020 compared to 2015-2019 (between ~25 to 60%) for all regions. For CO, negative anomalies were observed for all regions with the largest decrease for South America of up to ~40%. The NO2/CO ratio indicated that specific sites (such as those in Spanish cities) were affected by biomass burning plumes, which outweighed the NO2 decrease due to the general reduction in mobility (ratio of ~60%). Analysis of the total oxidant (OX = NO2 + O3) showed that primary NO2 emissions at urban locations were greater than the O3 production, whereas at background sites, OX was mostly driven by the regional contributions rather than local NO2 and O3 concentrations. The present study clearly highlights the importance of meteorology and episodic contributions (e.g., from dust, domestic, agricultural biomass burning and crop fertilizing) when analysing air quality in and around cities even during large emissions reductions. There is still the need to better understand how the chemical responses of secondary pollutants to emission change under complex meteorological conditions, along with climate change and socio-economic drivers may affect future air quality. The implications for regional and global policies are also significant, as our study clearly indicates that PM2.5 concentrations would not likely meet the World Health Organization guidelines in many parts of the world, despite the drastic reductions in mobility. Consequently, revisions of air quality regulation (e.g., the Gothenburg Protocol) with more ambitious targets that are specific to the different regions of the world may well be required.

School nutrition program: Assessment of planning and nutritional recommendations of menus / Programa de nutrición escolar: Evaluación de la planificación y recomendaciones nutricionales de los menús

The aim of this study was to verify whether the portion sizes adopted by school lunch cooks were in accordance with nutritional recommendations by PNAE (Brazilian School Nutrition Program). Portion sizes corresponding to shallow and full measures were weighed on a digital scale in duplicate to determine the average weight of each food portion. Nutritional composition of meals was determined using the Brazilian Table of Food Composition. Total energy value (TEV), carbohydrates, proteins, lipids, iron, sodium, vitamin C and dietary fiber were compared with PNAE recommendations for schoolchildren. As a result, two menu proposals with adequate portion sizes were developed. TEV and carbohydrate recommendations were met in the shallow portion size and exceeded recommendations in the full measure. Both shallow and full portions exceeded recommendations for protein, fat and sodium. The values found for dietary fiber, iron and vitamin C were in accordance with PNAE recommendations in both portion sizes. The menu proposals were in accordance with nutritional recommendations except for sodium, which remained slightly above limits. The study showed the need for the creation of manufacturing technical cards aimed at standardizing the portioning of foods/dishes offered to schoolchildren, as well as the training of school lunch cooks.

Verificar si el tamaño de las porciones adoptadas por los cocineros de los almuerzos escolares está de acuerdo con las recomendaciones nutricionales del PNAE (Programa Brasileño de Nutrición Escolar). Los tamaños de las porciones correspondientes a mediciones, poco profundas y completas, se pesaron en una balanza digital para determinar el peso promedio de cada porción de alimento. Se comparó el valor energético total (VET), carbohidratos, proteínas, lípidos, hierro, sodio, vitamina C y fibra dietética con las recomendaciones de PNAE para escolares. Como resultado, se desarrollaron dos propuestas de menú con la adecuación del tamaño de las porciones. Las recomendaciones VET y carbohidratos se cumplieron en el tamaño de la porción relacionada con la medida poco profunda. Tanto las mediciones poco profunda y completas superaron las recomendaciones de proteínas, grasas y sodio. Los valores encontrados para fibra dietética, hierro y vitamina C alcanzaron las recomendaciones de PNAE en ambos tamaños de porciones. Las propuestas de menús alcanzaron las recomendaciones nutricionales excepto el sodio, que se mantuvo ligeramente por encima de los límites. Es necesario elaborar tarjetas técnicas de fabricación con el objetivo de estandarizar la porción de alimentos que se ofrece a los escolares, así como la capacitación de cocineros.

Calcineurin interacts with PERK and dephosphorylates calnexin to relieve ER stress in mammals and frogs.

BACKGROUND: The accumulation of misfolded proteins within the endoplasmic reticulum (ER) triggers a cellular process known as the Unfolded Protein Response (UPR). One of the earliest responses is the attenuation of protein translation. Little is known about the role that Ca2+ mobilization plays in the early UPR. Work from our group has shown that cytosolic phosphorylation of calnexin (CLNX) controls Ca2+ uptake into the ER via the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) 2b. METHODOLOGY/PRINCIPAL FINDINGS: Here, we demonstrate that calcineurin (CN), a Ca2+ dependent phosphatase, associates with the (PKR)-like ER kinase (PERK), and promotes PERK auto-phosphorylation. This association, in turn, increases the phosphorylation level of eukaryotic initiation factor-2 alpha (eIF2-alpha) and attenuates protein translation. Data supporting these conclusions were obtained from co-immunoprecipitations, pull-down assays, in-vitro kinase assays, siRNA treatments and [35S]-methionine incorporation measurements. The interaction of CN with PERK was facilitated at elevated cytosolic Ca2+ concentrations and involved the cytosolic domain of PERK. CN levels were rapidly increased by ER stressors, which could be blocked by siRNA treatments for CN-Aalpha in cultured astrocytes. Downregulation of CN blocked subsequent ER-stress-induced increases in phosphorylated elF2-alpha. CN knockdown in Xenopus oocytes predisposed them to induction of apoptosis. We also found that CLNX was dephosphorylated by CN when Ca2+ increased. These data were obtained from [gamma32P]-CLNX immunoprecipitations and Ca2+ imaging measurements. CLNX was dephosphorylated when Xenopus oocytes were treated with ER stressors. Dephosphorylation was pharmacologically blocked by treatment with CN inhibitors. Finally, evidence is presented that PERK phosphorylates CN-A at low resting levels of Ca2+. We further show that phosphorylated CN-A exhibits decreased phosphatase activity, consistent with this regulatory mechanism being shut down as ER homeostasis is re-established. CONCLUSIONS/SIGNIFICANCE: Our data suggest two new complementary roles for CN in the regulation of the early UPR. First, CN binding to PERK enhances inhibition of protein translation to allow the cell time to recover. The induction of the early UPR, as indicated by increased P-elF2alpha, is critically dependent on a translational increase in CN-Aalpha. Second, CN dephosphorylates CLNX and likely removes inhibition of SERCA2b activity, which would aid the rapid restoration of ER Ca2+ homeostasis.

Vigilância epidemiológica de anomalias congênitas em um hospital universitário de Mato Grosso, Brasil / Surveillance of congenital anomalies in an university hospital of Mato Grosso, Brazil

Objetivos: Sistematizar o registro de Anomalias Congênitas (AC) em um Hospital Universitário de Mato Grosso e avaliar a qualidade do preenchimento do Campo 34 da Declaração de Nascidos Vivos (DVN). Método: Estudo prospectivo no qual foram avaliados, entre dezembro de 2005 e novembro de 2006, os recém-nascidos vivos (RNs) vivos do Hospital Geral Universitário visando identificar AC. Foram estabelecidas as frequências de AC na amostra e de outras variáveis. A adequação do preenchimento do Campo 34 da DNV foi estudada. Resultados: Foram 2.750 RNs, sendo 63 com AC (2,29%). Aproximadamente 80% dos RNs pesavam entre 2501 e 4000g. Os grupos de maior risco para AC foram os de 1501-2000 (7,46%) e de 1001-1500 gramas (5,17%); mães na faixa etária de 40-44 anos, seguida de 35-39 e 30-34 anos. Aproximadamente 85% das mães eram tercigestas. Observou-se maior frequência de AC entre as mulheres de 6 e 7 gestações. Nos RNs com AC, constatou-se que 30 eram do sexo masculino, 32, do sexo feminino e apenas 1 caso de intersexo. Agrupando: Anomalias de membros (16), anomalias do sistema nervoso (10), anomalias orofaciais (9), anomalia genital (6), defeitos de parede abdominal (5), síndrome de Down (3), anomalias do sistema respiratório (3), acondroplasia (1), anomalias múltiplas (4) anomalias não agrupadas (6). Em 23 casos, o preenchimento do Campo 34 foi feito de maneira correta. No restante (63,49%), o preenchimento foi incorreto ou não existente. Conclusão: Há subregistro de AC no Hospital estudado. O preenchimento do Campo 34 tem sido sistematicamente negligenciado, acarretando prejuízos nos registros oficiais.

To systematise the record of Congenital anomalies (CA) in a University Hospital of Mato Grosso and assess the quality of the completion of the Field 34 of Declaration of Live Births (DLB). Methods: Prospective which were evaluated between December 2005 and November 2006 the University General Hospital of living newborn (LN) to identify CA. Have been established in the frequencies of CA sample and other variables. The adequacy of the completion of Field 34 of DLB was studied. Results: There were 2,750 LN, 63 with CA (2.29%). Approximately 80% of LN weighs between 2501 and 4000g. The groups most at risk for CA were those of 1501-2000 (7.46%) and 1001-1500grams (5.17%); mothers in the age group of 40-44 years, followed by 35-39 and 30-34 years old. Approximately 85% of mothers had 3 pregnancies. Increased frequency of CA was observed between women, 6 and 7 pregnancies. In LN with CA, it was found that 30 were male, 32 female and only 1 intersex. Combining: Anomalies of members (16), disorders of the nervous system (10), abnormal orofacial (9), genital anomaly (6), defects in the abdominal wall (5), Down syndrome (3), disorders of the respiratory system (3), achondroplasia (1), multiple anomalies (4) anomalies not grouped (6). In 23 cases, the completion of the Field 34 has been done so correctly. In the remainder (63.49%), the filling was incorrect or non-existent. Conclusion: There a few registration of CA in Hospital studied. The completion of the Field 34 has been systematically neglected, resulting in losses official records.

Towards the definition of a core of microorganisms involved in anaerobic digestion of sludge.

The microbial consortium involved in anaerobic digestion has not yet been precisely characterized and this process remains a 'black box' with limited efficiency. In this study, seven anaerobic sludge digesters were selected based on technology, type of sludge, process and water quality. The prokaryotic community of these digesters was examined by constructing and analysing a total of 9890 16S rRNA gene clones. Libraries were constructed using primers specific for the Bacteria and Archaea domains for each digester, respectively. After phylogenetic affiliation, the libraries were compared using statistical tools to determine the similarities or differences among the seven digesters. Results show that the prokaryotic community of an anaerobic digester is composed of phylotypes commonly found in all anaerobic digesters sampled and also of specific phylotypes. The Archaea community is represented by an equilibrium among a restricted number of operational taxonomic units (OTUs). These OTUs are affiliated with Methanosarcinales, Methanomicrobiales and Arc I phylogenetic groups. Statistical analysis revealed that the Bacteria community can be described as a three component model: one-third making up a core group of phylotypes common to most of the digesters, one-third are phylotypes shared among a few digesters and another one-third are specific phylotypes. The core group is composed of only six OTUs affiliated with Chloroflexi, Betaproteobacteria, Bacteroidetes and Synergistetes. Its role in anaerobic degradation appears critical to investigate. This comparison of anaerobic digester populations is a first step towards a future understanding of the relationship among biodiversity, operating conditions and digester efficiency.

Fidedignidade e completude dos prontuários médicos em relação aos eventos ou reações adversas em pesquisa clínica / Reliability and completeness of medical records in relation to events or adverse reactions in clinical research

Sem resumo.

Fidedignidade e completude dos prontuários médicos em relação aos eventos ou reações adversas em pesquisa clínica

Sem resumo.

Inhibition of apoptotic potency by ligand stimulated thyroid hormone receptors located in mitochondria.

We recently reported that shortened thyroid hormone receptor isoforms (TRs) can target mitochondria and acutely modulate inositol 1,4,5 trisphosphate (IP3)-mediated Ca2+ signaling when activated by thyroid hormone 3,5,3'-tri-iodothyronine (T3). Stimulation occurs via an increase in mitochondrial metabolism that is independent of transcriptional activity. Here, we present evidence that T3-bound xTRbetaA1s inhibit apoptotic activity mediated by cytochrome c release. An assay for apoptotic potency was modified to measure the ability of Xenopus oocyte extracts to induce morphological changes in isolated liver nuclei. Apoptotic potency was significantly decreased when oocyte extract was prepared from xTRbetaA1 expressing oocytes and treated with T3. The ability of T3 treatment to inhibit apoptosis was dependent on the expression of xTRbetaA1s in the mitochondrial fraction, not in the cytosolic fraction. T3 treatment also increased the membrane potential of isolated mitochondria prepared from oocytes expressing xTRbetaA1s but not from wildtype controls. We conclude that T3 acutely regulates cytochrome c release in a potential dependent manner by activating TRs located within mitochondria.

Multiphoton laser scanning microscopy as a tool for Xenopus oocyte research.

Multiphoton laser scanning microscopy (MPLSM) has become an increasingly invaluable tool in fluorescent optical imaging. There are several distinct advantages to implementing MPLSM as a Xenopus oocyte research tool. MPLSM increases signal-to-noise ratio and therefore increases image quality because there is no out-of-focus fluorescence as would be created in conventional or confocal microscopy. All the light that is generated can be collected and used to generate an image because point detection of descanned fluorescence is not required. This is particularly useful when imaging deep into tissue sections, as is necessary for Xenopus oocytes, which are notoriously large (approximately 1-mm diameter). Because multiphoton lasers use pulsed energy in the infrared wavelengths, the energy can also travel further into tissues with much less light scattering. Because there is no out-of-focus excitation, phototoxicity, photodamage, and photobleaching are significantly reduced, which is particularly important for long-term experiments that require the same region to be scanned repeatedly. Finally, multiple fluorophores can be simultaneously excited because of the broader absorption spectra of multiphoton dyes. In this chapter, we describe the advantages and disadvantages of using MPLSM to image Xenopus oocytes as compared to conventional and confocal microscopy. The practical application of imaging oocytes is demonstrated with specific examples.

Acoso moral y acoso sexual en el lugar de trabajo / Moral and sexual harassment at the work place

La historia del acoso moral laboral nos demuestra que es un concepto científico y legal que pone en riesgo psicosocial a su victima. Se le conoce por sus raices en inglés como: mobbing. En este ensayo investigativo analizaremos los elementos del mobbing y sus fases, asi como el perfil del acosado y las características y tendencias de las víctimas del psicoterror laboral. También se documentan casos por entrevistas cualitativas sobre el acoso sexual laboral y como afrontar la situación dentro del marco jurídico aplicable en Costa Rica y las formas de tramitar el acoso sexual en sede judicial.

Nontranscriptional modulation of intracellular Ca2+ signaling by ligand stimulated thyroid hormone receptor.

Thyroid hormone 3,5,3'-tri-iodothyronine (T3) binds and activates thyroid hormone receptors (TRs). Here, we present evidence for a nontranscriptional regulation of Ca2+ signaling by T3-bound TRs. Treatment of Xenopus thyroid hormone receptor beta subtype A1 (xTRbetaA1) expressing oocytes with T3 for 10 min increased inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ wave periodicity. Coexpression of TRbetaA1 with retinoid X receptor did not enhance regulation. Deletion of the DNA binding domain and the nuclear localization signal of the TRbetaA1 eliminated transcriptional activity but did not affect the ability to regulate Ca2+ signaling. T3-bound TRbetaA1 regulation of Ca2+ signaling could be inhibited by ruthenium red treatment, suggesting that mitochondrial Ca2+ uptake was required for the mechanism of action. Both xTRbetaA1 and the homologous shortened form of rat TRalpha1 (rTRalphaDeltaF1) localized to the mitochondria and increased O2 consumption, whereas the full-length rat TRalpha1 did neither. Furthermore, only T3-bound xTRbetaA1 and rTRalphaDeltaF1 affected Ca2+ wave activity. We conclude that T3-bound mitochondrial targeted TRs acutely modulate IP3-mediated Ca2+ signaling by increasing mitochondrial metabolism independently of transcriptional activity.

Rho small GTPases activate the epithelial Na(+) channel.

Small G proteins in the Rho family are known to regulate diverse cellular processes, including cytoskeletal organization and cell cycling, and more recently, ion channel activity and activity of phosphatidylinositol 4-phosphate 5-kinase (PI(4)P 5-K). The present study investigates regulation of the epithelial Na(+) channel (ENaC) by Rho GTPases. We demonstrate here that RhoA and Rac1 markedly increase ENaC activity. Activation by RhoA was suppressed by the C3 exoenzyme. Inhibition of the downstream RhoA effector Rho kinase, which is necessary for RhoA activation of PI(4)P 5-K, abolished ENaC activation. Similar to RhoA, overexpression of PI(4)P 5-K increased ENaC activity suggesting that production of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) in response to RhoA-Rho kinase signaling stimulates ENaC. Supporting this idea, inhibition of phosphatidylinositol 4-kinase, but not the RhoA effector phosphatidylinositol 3-kinase and MAPK cascades, markedly attenuated RhoA-dependent activation of ENaC. RhoA increased ENaC activity by increasing the plasma membrane levels of this channel. We conclude that RhoA activates ENaC via Rho kinase and subsequently activates PI(4)P 5-K with concomitant increases in PI(4,5)P(2) levels promoting channel insertion into the plasma membrane.

Ca2+-dependent redox modulation of SERCA 2b by ERp57.

We demonstrated previously that calreticulin (CRT) interacts with the lumenal COOH-terminal sequence of sarco endoplasmic reticulum (ER) calcium ATPase (SERCA) 2b to inhibit Ca2+ oscillations. Work from other laboratories demonstrated that CRT also interacts with the ER oxidoreductase, ER protein 57 (also known as ER-60, GRP58; ERp57) during folding of nascent glycoproteins. In this paper, we demonstrate that ERp57 overexpression reduces the frequency of Ca2+ oscillations enhanced by SERCA 2b. In contrast, overexpression of SERCA 2b mutants defective in cysteines located in intralumenal loop 4 (L4) increase Ca2+ oscillation frequency. In vitro, we demonstrate a Ca2+-dependent and -specific interaction between ERp57 and L4. Interestingly, ERp57 does not affect the activity of SERCA 2a or SERCA 2b mutants lacking the CRT binding site. Overexpression of CRT domains that disrupt the interaction of CRT with ERp57 behave as dominant negatives in the Ca2+ oscillation assay. Our results suggest that ERp57 modulates the redox state of ER facing thiols in SERCA 2b in a Ca2+-dependent manner, providing dynamic control of ER Ca2+ homeostasis.

Modeling the dependence of the period of intracellular Ca2+ waves on SERCA expression.

Contrary to intuitive expectations, overexpression of sarco-endoplasmic reticulum (ER) Ca(2+) ATPases (SERCAs) in Xenopus oocytes leads to a decrease in the period and an increase in the amplitude of intracellular Ca(2+) waves. Here we examine these experimental findings by modeling Ca(2+) release using a modified Othmer-Tang-model. An increase in the period and a reduction in the amplitude of Ca(2+) wave activity are obtained when increases in SERCA density are simulated while keeping all other parameters of the model constant. However, Ca(2+) wave period can be reduced and the wave amplitude and velocity can be significantly increased when an increase in the luminal ER Ca(2+) concentration due to SERCA overexpression is incorporated into the model. Increased luminal Ca(2+) occurs because increased SERCA activity lowers cytosolic Ca(2+), which is partially replenished by Ca(2+) influx across the plasma membrane. These simulations are supported by experimental data demonstrating higher luminal Ca(2+) levels, decreased periods, increased amplitude, and increased velocity of Ca(2+) waves in response to increased SERCA density.

Malaria parasites solve the problem of a low calcium environment.

The parasite responsible for malaria, Plasmodium falciparum, spends much of its life in the RBC under conditions of low cytosolic Ca2+. This poses an interesting problem for a parasite that depends on a Ca2+ signaling system to carry out its vital functions. This long standing puzzle has now been resolved by a clever series of experiments performed by Gazarini et al. (2003). Using advances in fluorescent Ca2+ imaging (Grynkiewics, G., M. Poenie, and R.Y. Tsien. 1985. J. Biol. Chem. 260:3440-3450; Hofer, A., and T. Machen. 1994. Am. J. Physiol. 267:G442-G451; Hofer, A.M., B. Landolfi, L. Debellis, T. Pozzan, and S. Curci. 1998. EMBO J. 17:1986-1995), these authors have elucidated the source of the Ca2+ gradient that allows the accumulation of intracellular Ca2+ within the parasite.

Cambios estructurales y funcionales en el corazón del hipertenso: estudio ecocardiográfico / Structural and functional changes of the hypertensive heart

Se estudiaron 15 sujetos hipertensos (HA), cuyo diagnóstico se documentó con monitoreo ambulatorio de presión arterial (MAPA). El comportamiento de las cifras tensionales se comparó con el de un grupo de 26 sujetos sanos (S). Asimismo, se practicó estudio ecocardiográfico 2-D y los parámetros de función ventricular obtenidos con este procedimiento se compararon con los encontrados en un grupo de 31 sujetos sanos. Con el MAPA se demostró que los HA tienen cifras de tensión arterial mayores que los sanos tanto en el día como en la noche (los primeros pierden su ritmo circadiano). Por otro lado, los HA muestran hipertrofia ventricular izquierda (HVI) con una función ventricular sistólica normal (FV). Se demuestra que la HVI es inapropiada y por lo tanto el estrés meridional sistólico se encuentra disminuído. La HVI, como mecanismo de adaptación, mantiene la FV normal a pesar de la sobrecarga de presión, sin aumentar el MVO2. La permanencia de dicha sobrecarga en el tiempo transforma la HVI en un proceso patológico, debido al déposito de colágena en el intersticio del corazón, el cual en fases avanzadas llega a ser excesivo. Este proceso de remodelación culmina con disfunción distólica, isquemia miocárdica, arritmias y muerte del paciente: por muerte súbita o por insuficiencia cardíaca. Esta última fase es la que constituye realmente la cardiopatía hipertensiva

Correlación de valores de péptido natriurético auricular con los de renina, angiotensina y aldosterona en pacientes hipertensos menores y mayores de 50 años / Correlation between atrial natriuretic peptide, renin, angiotensin and aldosterone in hypertensive patients younger or older than 50 years

Se compararon determinaciones por radioinmunoanálisis de péptido natriurético auricular (PHA), con los de renina, angiotensina y aldosterona (RAA) en 6 voluntarios sanos >50 años y en 5 sujetos sanos >50 años, con aquellos efectuados en 44 hipertensos esenciales >50 años, y 41>50 años. Los valores de PNA en voluntarios sanos fueron X = 44 ñ 7 PG/ml en los <50 años, y X = 87.33 ñ 14 PG/ml en los >50 años (p < 0.01). En hipertensos <50 años, 80 por ciento tuvieron valores normales (X = 63.8 ñ 10 PG/ml) y 20 por ciento, elevados (X = 131 ñ 6 PG/ml), P < 0.001. En hipertensos >50 años, 70 por ciento tuvieron PNA elevado (X = 260 ñ 114 PG/ml) y 30 por ciento, normal (X = 75 ñ 5 PG/ml), P < 0.001. Los valores de RAA fueron normales o bajos en 96 por ciento de los casos con PNA elevado, P < 0.001; en el 100 por ciento de los casos con RAA elevados, los valores de PNA fueron bajos (P < 0.0001). Esta correlación fue estadísticamente significativa para los hipertensos >50 años (PNA alto y RAA bajos), P < 0.001, así como para los valores de RAA altos, PNA bajo en pacientes <50 años (P < 0.001). De acuerdo con nuestros resultados, en pacientes hipertensos esenciales <50 años los valores de PNA son normales en la mayoría de los casos y elevados en la mayoría de los casos de hipertensión >50 años (P < 0.001). No obtuvimos una correlación significativa entre los valores de PNA y los signos de hipertrofia ventricular izquierda en ambos grupos. Como en reportes previos, hubo una relación inversamente proporcional entre los valores de RAA y los de PNA independiente de la edad. Se corrobora que el sistema de PNA es un mecanismo más, en la regulación de la presión arterial en los sujetos hipertensos mayores de 50 años