Oxidative Stress in Hypertensive Patients Induces an Increased Contractility in Vein Grafts Independent of Endothelial Function

Objective. To evaluate the impact of oxidative stress on vascular reactivity to vasoconstrictors and on nitric oxide (NO) bioavailability in saphenous vein (SV) graft with endothelial dysfunction from hypertensive patients (HT). Methods. Endothelial function, vascular reactivity, oxidative state, nitrites and NO release were studied in isolated SV rings from HT and normotensive patients (NT). Only rings with endothelial dysfunction were used. Results. HT rings presented a hyperreactivity to vasoconstrictors that was reverted by diphenylene iodonium (DPI). In NT, no effect of DPI was obtained, but Nω-nitro-L-arginine methyl ester (L-NAME) increased the contractile response. NO was present in SV rings without endothelial function. Nitrites were higher in NT than in HT (1066.1 ± 86.3 pmol/mg; n = 11 versus 487.8 ± 51.6; n = 23; P < 0.01) and inhibited by nNOS inhibitor. L-arginine reversed this effect. Antioxidant agents increased nitrites and NO contents only in HT. The anti-nNOS-stained area by immunohistochemistry was higher in NT than HT. HT showed an elevation of oxidative state. Conclusions. Extraendothelial NO counter-regulates contractility in SV. However, this action could be altered in hypertensive situations by an increased oxidative stress or a decreased ability of nNOS to produce NO. Further studies should be performed to evaluate the implication of these results in graft patency rates

Antioxidant treatment reverts increased arterial basal tone and oxidative stress in nephrectomized (5/6) hypertensive rats

Nonischemic 5/6 nephrectomized rat (NefR) is a model of chronic kidney disease. However, little is known about vascular dysfunction and its relation with hypertension in NefR. Aims. To evaluate possible alterations of endothelial function, NObioavailability, and basal tone in aorta from NefR and the role of oxidative stress. Sprague Dawley rats were divided into sham rats (SR), NefR, and NefR treated with tempol (NefR-T). Mean arterial pressure (MAP) and renal function were determined. In isolated aortic rings the following was measured: 1-endothelial function, 2-basal tone, 3-NO levels, 4-membrane potential (MP), and 5-oxidative stress. NefR increased MAP (SR: 119 ± 4 mmHg; =7; NefR: 169 ± 6; =8; < 0.001). Tempol did not modify MAP (NefR-T: 168 ± 10; =6; < 0.001). NefR showed endothelial dysfunction, increased basal tone and decreased NO levels (SR: 32 ± 2 nA; =7, NefR: 10 ± 2; =8; < 0.001). In both in vitro and in vivo tempol improves basal tone, NO levels, and MP. Oxidative stress in NefR was reverted in NefR-T. We described, for the first time, that aorta from NefR presented increased basal tone related to endothelial dysfunction and decreased NO-bioavailability. The fact that tempol improves NO-contents and basal tone, without decrease MAP, indicates that oxidative stress could be implicated early and independently to hypertension, in the vascular alterations.Fil: Marañón, Rodrigo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; Argentina. University Of Mississippi; Estados UnidosFil: Joo Turoni, Claudio Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; ArgentinaFil: Karbiner, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; ArgentinaFil: Salas, Nicolás Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; ArgentinaFil: Peral, Maria de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; Argentin

Pregnancy Protects Hyperandrogenemic Female Rats from Postmenopausal Hypertension

Polycystic ovary syndrome, the most common endocrine disorder in women of reproductive age, is characterized by hyperandrogenemia, obesity, insulin resistance, and elevated blood pressure. However, few studies have focused on the consequences of pregnancy on postmenopausal cardiovascular disease and hypertension in polycystic ovary syndrome women. In hyperandrogenemic female (HAF) rats, the hypothesis was tested that previous pregnancy protects against age-related hypertension. Rats were implanted with dihydrotestosterone (7.5 mg/90 days, beginning at 4 weeks and continued throughout life) or placebo pellets (controls), became pregnant at 10 to 15 weeks, and pups were weaned at postnatal day 21. Dams and virgins were then aged to 10 months (still estrous cycling) or 16 months (postcycling). Although numbers of offspring per litter were similar for HAF and control dams, birth weights were lower in HAF offspring. At 10 months of age, there were no differences in blood pressure, proteinuria, nitrate/nitrite excretion, or body composition in previously pregnant HAF versus virgin HAF. However, by 16 months of age, despite no differences in dihydrotestosterone, fat mass/or lean mass/body weight, previously pregnant HAF had significantly lower blood pressure and proteinuria, higher nitrate/nitrite excretion, with increased intrarenal mRNA expression of endothelin B receptor and eNOS (endothelial nitric oxide synthase), and decreased ACE (angiotensin-converting enzyme), AT1aR (angiotensin 1a receptor), and endothelin A receptor than virgin HAF. Thus, pregnancy protects HAF rats against age-related hypertension, and the mechanism(s) may be due to differential regulation of the nitric oxide, endothelin, and renin-angiotensin systems. These data suggest that polycystic ovary syndrome women who have experienced uncomplicated pregnancy may be protected from postmenopausal hypertension.Fil: Shawky, Noha M.. University Of Mississippi Medical Center; Estados UnidosFil: Patil, Chetan N.. Medical College Of Wisconsin; Estados UnidosFil: Dalmasso, Carolina. University of Kentucky; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Grupo Vinculado Centro de Investigación en Medicina Traslacional Severo R. Amuchástegui - Cimetsa | Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Grupo Vinculado Centro de Investigación en Medicina Traslacional Severo R. Amuchástegui - Cimetsa | Instituto de Investigación Médica Mercedes y Martín Ferreyra. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Grupo Vinculado Centro de Investigación en Medicina Traslacional Severo R. Amuchástegui - Cimetsa; ArgentinaFil: Marañón, Rodrigo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Romero, Damián Gastón. University Of Mississippi Medical Center; Estados UnidosFil: Drummond, Heather. University Of Mississippi Medical Center; Estados UnidosFil: Reckelhoff, Jane F.. University Of Mississippi Medical Center; Estados Unido

Una experiencia innovadora en la formación de recursos humanos en investigación desde el grado: programa articulado de docentes y auxiliares estudiantiles

La Cátedra de Fisiología de la Facultad de Medicina de la Universidad Nacional de Tucumán implementó un programa innovador de formación de jóvenes investigadores. Determinar el nivel de destreza alcanzado en las diferentes áreas abordadas durante la formación, según autovaloración de los participantes; y describir la percepción estudiantil sobre la influencia de la Escuela en el deseo de seguir una carrera investigativa en el futuro y la necesidad de incorporar programas similares a la currícula universitaria. Se realizó un estudio cuali-cuantitativo, descriptivo-exploratorio en estudiantes que participaron del programa. La recolección de datos se realizó mediante una encuesta, con previo consentimiento informado. Para su procesamiento y análisis, se utilizó Microsoft Excel 2016. Participaron 13 estudiantes. Según su autovaloración, adquirieron un buen nivel de destrezas en manejo de bioterio, medición de presión en ratas, histología y necropsia, y niveles menos favorables en exposición y redacción de trabajos. El 50% participaron como autores y expositores. El programa influyó en la decisión de seguir una carrera investigativa y todos consideran importante incluirlo en la currícula. Este programa muestra un impacto positivo promoviendo la incorporación temprana de estudiantes al ámbito investigativo, formándose a la par de investigadores profesionales y auxiliares estudiantiles. Su integración al plan de estudios puede incluir a todos los alumnos. Es responsabilidad educativa conectar investigación, docencia y medicina clínica, para beneficio de las personas.Fil: Gepner, Maia Einath. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Salses, Florencia Marlen del Milagro. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Alberstein, Ramón Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Sanchez, Romel Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Marañón, Rodrigo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Peral de Bruno, María. Universidad Nacional de Tucumán. Facultad de Medicina; Argentin

Una experiencia innovadora en la formación de recursos humanos en investigación desde el grado: programa articulado de docentes y auxiliares estudiantiles

La Cátedra de Fisiología de la Facultad de Medicina de la Universidad Nacional de Tucumán implementó un programa innovador de formación de jóvenes investigadores. Determinar el nivel de destreza alcanzado en las diferentes áreas abordadas durante la formación, según autovaloración de los participantes; y describir la percepción estudiantil sobre la influencia de la Escuela en el deseo de seguir una carrera investigativa en el futuro y la necesidad de incorporar programas similares a la currícula universitaria. Se realizó un estudio cuali-cuantitativo, descriptivo-exploratorio en estudiantes que participaron del programa. La recolección de datos se realizó mediante una encuesta, con previo consentimiento informado. Para su procesamiento y análisis, se utilizó Microsoft Excel 2016. Participaron 13 estudiantes. Según su autovaloración, adquirieron un buen nivel de destrezas en manejo de bioterio, medición de presión en ratas, histología y necropsia, y niveles menos favorables en exposición y redacción de trabajos. El 50% participaron como autores y expositores. El programa influyó en la decisión de seguir una carrera investigativa y todos consideran importante incluirlo en la currícula. Este programa muestra un impacto positivo promoviendo la incorporación temprana de estudiantes al ámbito investigativo, formándose a la par de investigadores profesionales y auxiliares estudiantiles. Su integración al plan de estudios puede incluir a todos los alumnos. Es responsabilidad educativa conectar investigación, docencia y medicina clínica, para beneficio de las personas.Fil: Gepner, Maia Einath. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Salses, Florencia Marlen del Milagro. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Alberstein, Ramón Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Sanchez, Romel Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Marañón, Rodrigo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Peral de Bruno, María. Universidad Nacional de Tucumán. Facultad de Medicina; Argentin

Sex differences in the structure and function of rat middle cerebral arteries

Wang S, Zhang H, Liu Y, Li L, Guo Y, Jiao F, Fang X, Jefferson JR, Li M, Gao W, Gonzalez-Fernandez E, Maranon RO, Pabbidi MR, Liu R, Alexander BT, Roman RJ, Fan F. Sex differences in the structure and function of rat middle cerebral arteries. Am J Physiol Heart Circ Physiol 318: H1219 –H1232, 2020. First published March 27, 2020; doi:10.1152/ajpheart.00722.2019.—Epidemiological studies demonstrate that there are sex differences in the incidence, prevalence, and outcomes of cerebrovascular disease (CVD). The present study compared the structure and composition of the middle cerebral artery (MCA), neurovascular coupling, and cerebrovascular function and cognition in young Sprague-Dawley (SD) rats. Wall thickness and the inner diameter of the MCA were smaller in females than males. Female MCA exhibited less vascular smooth muscle cells (VSMCs), diminished contractile capability, and more collagen in the media, and a thicker internal elastic lamina with fewer fenestrae compared with males. Female MCA had elevated myogenic tone, lower distensibility, and higher wall stress. The stress/strain curves shifted to the left in female vessels compared with males. The MCA of females failed to constrict compared with a decrease of 15.5 ± 1.9% in males when perfusion pressure was increased from 40 to 180 mmHg. Cerebral blood flow (CBF) rose by 57.4 ± 4.4 and 30.1 ± 3.1% in females and males, respectively, when perfusion pressure increased from 100 to 180 mmHg. The removal of endothelia did not alter the myogenic response in both sexes. Functional hyperemia responses to whisker-barrel stimulation and cognition examined with an eight-arm water maze were similar in both sexes. These results demonstrate that there are intrinsic structural differences in the MCA between sexes, which are associated with diminished myogenic response and CBF autoregulation in females. The structural differences do not alter neurovascular coupling and cognition at a young age; however, they might play a role in the development of CVD after menopause. NEW & NOTEWORTHY Using perfusion fixation of the middle cerebral artery (MCA) in calcium-free solution at physiological pressure and systematically randomly sampling the sections prepared from the same M2 segments of MCA, we found that there are structural differences that are associated with altered cerebral blood flow (CBF) autoregulation but not neurovascular coupling and cognition in young, healthy Sprague-Dawley (SD) rats. Understanding the intrinsic differences in cerebrovascular structure and function in males and females is essential to develop new pharmaceutical treatments for cerebrovascular disease (CVD).Fil: Wang, Shaoxun. University Of Mississippi Medical Center; Estados UnidosFil: Zhang, Huawei. University Of Mississippi Medical Center; Estados UnidosFil: Liu, Yedan. University Of Mississippi Medical Center; Estados UnidosFil: Li, Longyang. University Of Mississippi Medical Center; Estados UnidosFil: Guo, Ya. University Of Mississippi Medical Center; Estados UnidosFil: Jiao, Feng. Peking University People's Hospital; China. University Of Mississippi Medical Center; Estados UnidosFil: Fang, Xing. University Of Mississippi Medical Center; Estados UnidosFil: Jefferson, Joshua R.. University Of Mississippi Medical Center; Estados UnidosFil: Li, Man. University Of Mississippi Medical Center; Estados UnidosFil: Gao, Wenjun. University Of Mississippi Medical Center; Estados UnidosFil: Gonzalez Fernandez, Ezekiel. University Of Mississippi Medical Center; Estados UnidosFil: Marañón, Rodrigo Oscar. University Of Mississippi Medical Center; Estados Unidos. Universidad Nacional de Tucumán. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Pabbidi, Mallikarjuna R.. University Of Mississippi Medical Center; Estados UnidosFil: Liu, Ruen. Peking University People's Hospital; ChinaFil: Alexander, Barbara T.. University Of Mississippi Medical Center; Estados UnidosFil: Roman, Richard J.. University Of Mississippi Medical Center; Estados UnidosFil: Fan, Fan. University Of Mississippi Medical Center; Estados Unido

Large-scale assessment of regeneration and diversity in Mediterranean planted pine forests along ecological gradients

15 pages, 4 figures, 4 tables, 87 references.There is increasing concern regarding sustainable management and restoration of planted forests, particularly in the Mediterranean Basin where pine species have been widely used. The aim of this study was to analyse the environmental and structural characteristics of Mediterranean planted pine forests in relation to natural pine forests. Specifically, we assessed recruitment and woody species richness along climatic, structural and perturbation gradients to aid in developing restoration guidelines.Location Continental Spain. We conducted a multivariate comparison of ecological characteristics in planted and natural stands of main Iberian native pine species (Pinus halepensis, Pinus pinea, Pinus pinaster, Pinus nigra and Pinus sylvestris). We fitted species-specific statistical models of recruitment and woody species richness and analysed the response of natural and planted stands along ecological gradients. Planted pine forests occurred on average on poorer soils and experienced higher anthropic disturbance rates (fire frequency and anthropic mortality) than natural pine forests. Planted pine forests had lower regeneration and diversity levels than natural pine forests, and these differences were more pronounced in mountain pine stands. The largest differences in recruitment – chiefly oak seedling abundance – and species richness between planted and natural stands occurred at low-medium values of annual precipitation, stand tree density, distance to Quercus forests and fire frequency, whereas differences usually disappeared in the upper part of the gradients.Main conclusions Structural characteristics and patterns of recruitment and species richness differ in pine planted forests compared to natural pine ecosystems in the Mediterranean, especially for mountain pines. However, management options exist that would reduce differences between these forest types, where restoration towards more natural conditions is feasible. To increase recruitment and diversity, vertical and horizontal heterogeneity could be promoted by thinning in high-density and homogeneous stands, while enrichment planting would be desirable in mesic and medium-density planted forests.This research was supported by INTERBOS3-CGL2008-04503- C03-03 (MCI) and SUM2008-00004-C03-01 (INIA) projects. P.R.B. was supported by a FPU fellowship from the Spanish MEC (AP2008-01325). We thank the MARM (Ministerio de Medio Ambiente, Medio Rural y Marino, Dirección General de Medio Natural y Política Forestal) for granting the access to the Spanish Forest Inventory Data.Peer reviewe

Anaerobic digestion of screenings for biogas recovery

Screenings comprise untreatable solid materials that have found their way into the sewer. They are removed during preliminary treatment at the inlet work of any wastewater treatment process using a unit operation termed as a screen and at present are disposed of to landfill. These materials, if not removed, will damage mechanical equipment due to its heterogeneity and reduce overall treatment process, reliability and effectiveness. That is why this material is retained and prevented from entering the treatment system before finally being disposed of. The amount of biodegradable organic matter in screenings often exceeds the upper limit and emits a significant amount of greenhouse gases during biodegradation on landfill. Nutrient release can cause a serious problem of eutrophication phenomena in receiving waters and a deterioration of water quality. Disposal of screenings on landfill also can cause odour problem due to putrescible nature of some of the solid material. In view of the high organic content of screenings, anaerobic digestion method may not only offer the potential for energy recovery but also nutrient. In this study, the anaerobic digestion was performed for 30,days, at controlled pH and temperature, using different dry solids concentrations of screenings to study the potential of biogas recovery in the form of methane. It was found screenings have physical characteristics of 30% total solids and 93% volatile solids, suggesting screenings are a type of waste with high dry solids and organic contents. Consistent pH around pH 6.22 indicates anaerobic digestion of screenings needs minimum pH correction. The biomethane potential tests demonstrated screenings were amenable to anaerobic digestion with methane yield of 355,m3/kg VS, which is comparable to the previous results. This study shows that anaerobic digestion is not only beneficial for waste treatment but also to turn waste into useful resources