Application of a Fenton process for the pretreatment of an iron-containing oily sludge: A sustainable management for refinery wastes.

The feasibility of a Fenton-type process for the pretreatment of an oily refinery sludge has been explored taking advantage of the iron contained in the own sludge. This process reduces the content of total petroleum hydrocarbons (TPHs) accompanied by an increase in the total organic carbon concentration in the liquid phase. The effect of the temperature and the hydrogen peroxide loading was thoroughly studied in this work being the oxidant concentration the most critical parameter. Under 60 °C and 90 g/L of initial hydrogen peroxide concentration, the Total Organic Carbon (TOC) of the liquid phase was increased up values of 1336 mg/L and with a remarkable contribution of acetic acid as final oxidized compound (396 mgC/L). Additionally, nitrogen and phosphorous compounds were also dissolved in the aqueous phase achieving values of 250 mg/L and 7 mg/L for total Kjeldahl nitrogen and total phosphorous, respectively. Respirometry assays of the aqueous phase after the Fenton pretreatment have evidenced an increase of biodegradability up to 49% which makes this phase suitable for further biological processing in the refinery scheme. The reduction of the content of TPHs (61%) of the oily sludge, has also improved the settleability of the treated effluent (reducing the capillary suction time (CST) in ca. 88%).

Comprehensive characterization of an oily sludge from a petrol refinery: A step forward for its valorization within the circular economy strategy.

Refinery treatment plants produce large quantities of oily sludge during the petroleum refining processes. The hazardousness associated with the disposal of these wastes, make necessary the development of innovative technologies to handle it adequately, linked to the concepts of circular economy and environmental sustainability. This work provides for the first time a methodology for the deep characterization of this kind of wastes and consequently new insights regarding its valorization. A review of works dealing with the characterization of this type of wastes has been addressed evidencing the complexity and variability of these effluents. The oily sludge under study contains a high concentration of Chemical Oxygen Demand of 196 g COD/L, a Total Kjeldahl Nitrogen of 2.8 g TKN/kg, a phosphorous content as PO43- of 7 g/kg, as well as a great presence of heavy metals in a different range of concentrations. This sludge is composed of three different phases: oily, aqueous and solid. The oily and the solid phases present high percentages of carbon content (84 and 26%, respectively), related to the presence of alkanes ranged from n-C9 to n-C44. Therefore, it could be possible their valorization by the synthesis of catalyst and/or adsorbents. A dark fermentation process could be also proposed for the oily phase to obtain H2 as an alternative energy source. Finally, the aqueous phase contains low carbon and nutrients concentration. A previous thermal pre-treatment applied to the oily sludge might increase nutrient and organic loading in the aqueous phase due to solid destruction, making this aqueous effluent suitable for a further conventional biological treatment.

Impact of evolving greenhouse gas forcing on the warming signal in regional climate model experiments.

Variations in the atmospheric concentrations of greenhouse gases (GHG) may not be included as external forcing when running regional climate models (RCMs); at least, this is a non-regulated, non-documented practice. Here we investigate the so far unexplored impact of considering the rising evolution of the CO2, CH4, and N2O atmospheric concentrations on near-surface air temperature (TAS) trends, for both the recent past and the near future, as simulated by a state-of-the-art RCM over Europe. The results show that the TAS trends are significantly affected by 1-2 K century-1, which under 1.5 °C global warming translates into a non-negligible impact of up to 1 K in the regional projections of TAS, similarly affecting projections for maximum and minimum temperatures. In some cases, these differences involve a doubling signal, laying further claim to careful reconsideration of the RCM setups with regard to the inclusion of GHG concentrations as an evolving external forcing which, for the sake of research reproducibility and reliability, should be clearly documented in the literature.

Fluctuating periodic solutions and moment boundedness of a stochastic model for the bone remodeling process.

In this work, we model osteoclast-osteoblast population dynamics with random environmental fluctuations in order to understand the random variations of the bone remodeling process in real life. For this purpose, we construct a stochastic differential model for the interactions between the osteoclast and osteoblast cell populations using the parameter perturbation technique. We prove the existence of a globally attractive positive unique solution for the stochastically perturbed system. Also, the stochastic boundedness of the solution is demonstrated using its p-th order moments for p ≥ 1. Finally, we show that the introduction of noise in the deterministic model provides a fluctuating periodic solution. Numerical evidence supports our theoretical results and a discussion of the results is carried out.

Resultados precoces y tardíos en resecciones ampliadas en cáncer de colon T4b / Early and late results after multivisceral resections for T4b colonic cancer

Objetivos: Describir las tasas de morbilidad y mortalidad postoperatorias de las resecciones ampliadas de colon en pacientes con tumor en estadio T4b. Material y métodos: Serie de casos, que incluye pacientes con adenocarcinoma colónico clínicamente con compromiso de estructuras adyacentes (T4b), intervenidos de resección multivisceral entre los años 2005 y 2014. Fueron excluidos pacientes con metástasis, con bordes macroscópicamente comprometidos y con datos clínicos incompletos. Las variables resultado fueron la morbilidad y mortalidad postoperatorias a los 30 días. Se aplicó estadística descriptiva. Para las variables categóricas se utilizaron porcentajes, y para las variables continuas se utilizaron la media y mediana como medidas de tendencia central y la desviación estándar o rango como medidas de dispersión. Se aplicó el método de Kaplan-Meier para la sobrevida, y pruebas de Chi cuadrado y log-Rank para el análisis de sobrevida por subgrupos. Resultados: De un universo de 483 pacientes intervenidos por adenocarcinoma colónico, 71 fueron T4b. Se aplicaron criterios de exclusión, resultando una muestra de 46 pacientes. Los órganos más frecuentemente comprometidos fueron: intestino delgado, epiplón, pared abdominal y otro segmento colónico. La morbilidad y mortalidad postoperatorias, de un 21,7 y un 6,5%, respectivamente. Influyeron significativamente en la sobrevida la edad, el antecedente de quimioterapia adyuvante, la presencia de inestabilidad microsatelital y la diferenciación del tumor. Conclusiones: El compromiso multivisceral de los tumores colónicos no es infrecuente, con un 9,5% para nuestra serie. La resección R0 es el tratamiento de elección. Influyen en el pronóstico el tipo histológico y el comportamiento biológico del tumor, así como la quimioterapia adyuvante y la edad del paciente.

Aims: To describe postoperative morbidity and mortality rates in multivisceral resections for T4b colon cancer. Material and methods: Case series of patients diagnosed of T4b colonic adenocarcinoma who underwent multivisceral resection between 2005 and 2014. There were excluded those patients who had metastases, R2 resection and incomplete clinical data. Result variables were morbidity and mortality at 30 days. It was performed descriptive statistic using percentage estimation for categories, average and median for continuous variables and standard deviation or rank as measures of statistical dispersion. It was used Kaplan-Meier method for survival and chi-square and log-Rank for subgroups analysis. Results: From a universe of 483 patients who underwent surgery for colonic adenocarcinoma, whom 71 were staged as T4b, after exclusion criteria were applied it resulted a sample of 46 patients. The small bowel, omentum, abdominal wall and other colonic segment were the more often compromised organs. Postoperative morbidity and mortality were 21.7 and 6.5% respectively. The age, history of adjuvant chemotherapy, presence of microsatellite instability and tumor differentiation had a significant impact in survival. Conclusions: Multivisceral affection in colonic cancer is not uncommon, 9.5% in our series. R0 resection is the treatment of choice. Patient outcome depends on his age, histologic and biologic characteristics of the tumor and adjuvant treatment.

Stability analysis of a Komarova type model for the interactions of osteoblast and osteoclast cells during bone remodeling.

In order to analyze theoretically the dynamics of osteoblast and osteoclast cells in the bone remodeling process we first consider a simplified Komarova model. The existence of periodic solutions, which is consistent with the biophysical phenomenon, has been observed only numerically for the general model. By a stability analysis of the simplified model we provide sufficient conditions to obtain existence and uniqueness of positive periodic solutions. Considering recent biological evidence about the participation of another cells like osteocytes in the regulation of bone remodeling, we incorporate to the simplified model a new term as a way to model the signaling of external agents in the remodeling process. Finally, we demonstrate that this new model has stable positive non-periodic solutions. All the theoretical results are accompanied by computational simulations.

Hypercholesterolemia increases plasma saturated and n-6 fatty acids altering prostaglandin homeostasis and promotes endothelial dysfunction in rabbits.

The present study evaluated the plasma fatty acid levels and the vascular prostaglandin (PG) release in a rabbit model of early hypercholesterolemia with endothelial dysfunction. Rabbits were fed either a control diet (CD) or a diet containing 1 % cholesterol (HD) for 5-6 weeks. The level of fatty acids was measured in plasma. The levels of PG and nitric oxide (NO) released from the aorta were also determined. Vascular morphology of the aorta was characterized by intima and media thickness measurements. The rabbits fed with HD had higher levels of arachidonic acid (ARA) and lower levels of oleic acid. The linoleic acid level was unchanged. PGI(2) and NO were diminished and PGF(2α) levels, the PGI(2)/TXA(2) ratio and the intima/media ratio were increased in rabbits fed with HD. In conclusion, feeding HD for a short period increased ARA plasma levels and unbalanced release of vasodilator/vasoconstrictor PG redirected the pathway to vasoconstrictor metabolite release. These lipid metabolism alterations in addition to the reduced NO levels and the moderate changes in the vascular morphology contributed to the endothelial dysfunction in this animal model. Therefore, the present findings support the importance of early correction or prevention of high cholesterol levels to disrupt the endothelial dysfunction process that leads to cardiovascular disease.

Using molecular markers for pedigree reconstruction of the greater amberjack (Seriola dumerili) in the absence of parental information.

Ensuring appropriate levels of genetic diversity in captive populations is essential to avoid inbreeding and loss of rare alleles by genetic drift. Pedigree reconstruction and parentage analysis in the absence of parental genotypes can be a challenging task that relies in the assignment of sibship relationships among the offspring. Here, we used eight highly variable microsatellite markers and three different assignment methods to reconstruct the most likely genotypes of a parental group of wild Seriola dumerili fish based on the genotypes of six cohorts of their offspring, to assess their relative contributions to the offspring. We found that a combination of the four most variable microsatellites was enough to identify the number of parents and their contribution to the offspring, suggesting that the variability of the markers can be more critical than the number of markers. Estimated effective population sizes were lower than the number of breeders and variable among years. The results suggest unequal parental contribution that should be accounted for breeding programs in the future.

Compromiso vesical en síndrome de Guillain-Barré: a propósito de un caso / Bladder involvement in Guillain-Barre syndrome: a case study

Introducción: El Síndrome de Guillain-Barré (SGB) es una enfermedad autoinmune caracterizada por debilidad muscular, arreflexia y disociación albúmino-citológica en líquido cerebroespinal, cuya incidencia clásica a nivel internacional suele uniformarse alrededor de 0,6 a 4 casos por 100.000 al año. Presentación del caso: Paciente de 45 años, sexo femenino, quien ingresó al Servicio de Urgencia del Hospital de Temuco derivada desde Lonquimay, por debilidad progresiva de las cuatro extremidades. En Lonquimay la paciente requirió sonda vesical por retención urinaria. Es diagnosticada con SGB, hospitalizándose en Unidad de Cuidados Intensivos, requiriendo ventilación asistida y tratada mediante plasmaféresis, presentando neumonía como complicación relacionada a la ventilación mecánica y recuperando íntegramente función vesical. Discusión: El compromiso vesical no es descrito como un factor importante en el diagnóstico, siendo controversial aquella afirmación por varios autores.

Introduction: Guillain-Barre syndrome (GBS) is an autoimmune disease characterized by muscle weakness, areflexia and albumin-cytological dissociation in cerebrospinal fluid, the incidence has been reported to be relatively uniform between 0.6 to 4 cases per 100.000 per year. Case report: Patient of 45 years old, female, admitted to the emergency department of Hospital de Temuco derived from Lonquimay by progressive weakness of four extremities. In Lonquimay the patient required bladder catheterization for urinary retention. It was diagnosed with GBS, hospitalized in intensive care unit, requiring assisted ventilation and treated with plasmapheresis, developing pneumonia as a complication related to mechanical ventilation and fully recovered bladder function. Discussion: The bladder involvement is not described as an important factor in diagnosis and remains controversial this statement by several authors.

Effects of a diet lacking HUFA on lipid and fatty acid content of intestine and gills of male gilthead seabream (Sparus aurata L.) broodstock at different stages of the reproductive cycle.

A feeding experiment was carried out to determine the effect of a diet lacking n-3 and n-6 highly unsaturated fatty acids (HUFA) on lipid and fatty acid content in intestine and gills of male gilthead seabream (Sparus aurata L.) broodstock at different stages of the reproductive cycle: November (pre-spermatogenesis), March (spermatogenesis), and June (post-spermatogenesis). For this purpose, gilthead seabream broodstock were fed either a control diet (C) or an n-3 and n-6 HUFA-deficient diet (D). The results showed no changes in fatty acid content of polar lipids of intestine and gills from fish fed diet C at different stages of the reproductive cycle. However, significant changes were observed in the fatty acid content of neutral lipids in intestine but not in gills in this group. Thus, between November and March, saturates and n-3 HUFA decreased while monoenes increased. In June, the contents of these fatty acids had returned to their initial values (November). Moreover, in fish fed diet D, the fatty acid content of neutral lipid changed in both intestine and gills. In intestine NL, a decrease in saturates and n-3 HUFA and an increment in monoenes were observed from November to June. In gills, a decrease was also observed in n-3 HUFA from NL along the cycle. Nevertheless, n-6 HUFA content remained unchanged. These results show both tissue specificity in seasonal mobilization of fatty acids linked to reproductive processes and the influence of dietary fatty acids on body composition.

[Gender-related differences in functional assessment of serotonergic system in healthy young subjects]. / Diferencias de género en la exploración funcional del sistema serotoninérgico en jóvenes sanos.

INTRODUCTION: Prolactin stimulation test with serotonergic stimulants has been widely used in the study of diverse psychiatric disorders. However, the characterization of this response in normal subjects is still incomplete. OBJECTIVE: To compare the response to serotonin stimulation using dexfenfluramine, a specific serotonergic agent, in young healthy men and women, controlling the menstrual cycle. METHODS: A total of 10 women and 9 men, who were given 30 mg of dexfenfluramine orally, were studied and their levels of prolactin were measured on an hourly basis for a five-hour period. Baseline, maximum and delta values of prolactin were compared for both groups. RESULTS: According to the age groups studied (mean age for men: 19.9 +/- 2.5 years old; mean age for women: 20 +/- 1.5 years old), the prolactin maximum level and the response to prolactin (DPRL) were significantly higher in women (p-values: 0.02 and 0.04, respectively). CONCLUSIONS: Young healthy women show a greater response to stimulation with dexfenfluramine than young healthy men. Clinical and biological implications of this observation are discussed in the context of the currently available research papers.

Serotonin transporter polymorphism and fluoxetine effect on impulsiveness and aggression in borderline personality disorder.

INTRODUCTION: Impulsiveness and aggressiveness are characteristics of borderline personality disorder and are associated to a serotoninergic system dysfunction. Serotonin transporter polymorphisms have been linked to aggressive and impulsive behaviors. The short allele (S) in depression is associated to a worse response to selective serotonin reuptake inhibitors (SSRI). This study aims to study these polymorphisms to predict the response of aggressive and impulsive behaviors to SSRIs in borderline personality disorder. METHOD: Fifty-nine patients with DSM-IV borderline personality disorder in accordance with the International Personality Disorder Examination (IPDE) and without axis 1 disease were treated with flexible doses of fluoxetine for 12 weeks. The patients were evaluated with the Overt Aggression Scale Modified (OAS-M) at the beginning and at 2, 4, 8 and 12 weeks of treatment. Polymorphisms L and S of the serotonin transporter promoter region were determined. Response to fluoxetine of the LL carriers versus the S carriers (LS+SS) was compared. RESULTS: LL carriers had a better response than S carriers in the reduction of total OAS-M scores and on the aggressiveness and irritability components of the OAS-M. CONCLUSIONS: L-allele carriers responded better to fluoxetine than S carriers, in a similar way as in depression. The S allele may represent a common factor of bad response to SSRI in diseases associated to serotoninergic system dysfunction.

Lipid and fatty acid content in wild white seabream (Diplodus sargus) broodstock at different stages of the reproductive cycle.

The lipid and fatty acid content of the gonads, liver and muscle of wild white seabream males and females was studied at different stages of the reproductive cycle. Samples were taken from mature white seabream at pre-spawning (November), mid-spawning (March) and post-spawning (June) stages. The results showed that lipid accumulates in gonads and muscle from November to March. The gonadosomatic index (GSI) was also increased during this period. Male gonads showed a greater increase in polar lipid (PL) than neutral (NL), while female gonads displayed the reverse. The increase in both neutral and polar lipid was higher in the muscle of males than in females. In the same period, male livers showed no changes either in lipid content or the hepatosomatic index (HSI), while female livers registered an increase in both lipid content and HSI. Between March and June, in both males and females, total, neutral and polar lipid decreased sharply in the gonads and muscle. Muscular lipid content reduction was more pronounced in males than females. On the other hand, the lipid content of the liver in males and females remained relatively constant. In general terms, the amounts of major fatty acids (16:0, 18:1n-9, 20:5n-3 and 22:6n-3) in gonadal and muscular polar and neutral lipid in both males and females increased from November to March and declined thereafter. Variations of the liver fatty acid content were less extreme. In the period from mid-spawning to post-spawning, the presence of 20:4n-6 in polar and neutral lipid increased to a notable extent in all organs studied.

Lipid dynamics and plasma level changes of 17beta-estradiol and testosterone during the spawning season of gilthead seabream (Sparus aurata) females of different ages.

The present study was undertaken to evaluate whether the age of brood stock females of Sparus aurata affects the mobilization of lipids from muscle and liver towards the gonads to aid in oocyte development. Taking into account the role some hormones play in lipid mobilization the production of 17beta-estradiol (E2) and testosterone (T) was also measured throughout the spawning season. Four groups of fish were established consisting of 3-, 4-, 5- and 6-year-old females (1.3, 1.5, 2.3 and 2.8 kg average weight, respectively), maintained in separate tanks together with a number of two-year-old males. The results for all four groups showed no variations in fish total length between the beginning and end of the experimental period. However, losses were recorded both of body weight and condition factor. In general terms, there were no significant differences in the plasma levels of E2, T and the gonadosomatic (GSI) and hepatosomatic (HSI) index among the four groups throughout the spawning season. In all groups, the plasma levels of E2, T, GSI and HSI were at their lowest at the end of spawning. Between December (pre-spawning) and March (mid-spawning), all groups suffered depletion of the lipid content of liver and muscle, while gonad lipid content remained constant. The mobilization of lipids from liver and muscle to contribute to the upkeep of the gonadal lipid involved the mobilization of all the fatty acid groups, saturates, monoenes, n-6, n-3, and n-3 HUFA. A good correlation existed between the percentage of the various fatty acid groups transferred from muscle and the age of the reproductive females. However, the greater lipid mobilization from muscle matching the greater age of the reproductive females did not result in greater lipid gonadal reserves or greater body size, suggesting that reproduction on the part of older females requires greater effort. Despite this, the results as a whole indicated that lipogenic capacity, considered as the mobilization of lipids from muscle and liver towards the gonad for the development of oocytes, is unaffected by age in reproductive 3- to 6-year-old gilthead seabream females.

[Effect of angiotensin II and alpha2 adrenergic receptor antagonists on angiotensin II-stimulated nitric oxide release]. / Efecto de antagonistas de los receptores de angiotensina II y alpha 2 adrénergicos sobre la liberación de óxido nitrico inducida por angiotensina II.

The aim of the present work was to characterize the interaction between the adrenergic system and angiotensin II-stimulated nitric oxide (NO) release in rabbit aorta. Rings of thoracic aorta were placed in an isolated organ bath. Equilibration was performed during 30 min, and after washing, angiotensin II was added at different concentrations, during 20 min. In another group two stimulations were performed with an interval of 60 min. Angiotensin II antagonists: losartan, PD 123319 and Sar1-Leu8-angiotensin II, alpha 2 adrenergic antagonist: yohimbine, all at 10(-5) M and L-NAME or D-NAME 10(-2) M, were added before stimulation with angiotensin II 10(-6) M or 5.10(-6) M. In another group, besides losartan or PD 123319, yohimbine was added. Nitrite determination was performed with Griess reagent. Angiotensin II 10(-8) to 10(-6) M increased NO metabolite production measured as nitrites referred to the control. In higher concentrations there was a diminution in relation to 10(-6) M. Angiotensin II nitrite release fell in the second stimulation with the hormone in all cases, whereas it was blocked by L-NAME. It was increased by angiotensin II antagonist only at maximal concentrations of the hormone, an effect abolished by yohimbine. Likewise, yohimbine diminished nitrite production at concentrations of angiotensin II of 5.10(-6) but not at 10(-6) M. These results allow us to postulate that NO release induced by angiotensin II would be in part mediated by alpha 2 receptors. Angiotensin II antagonists unmask these effects at maximal concentrations of the hormone, whereas at supramaximal concentrations inhibitory mechanisms would prevail, which would be balanced by alpha 2 activation.

Endothelium-dependent desensitization to angiotensin II in rabbit aorta: the mechanisms involved.

The aim of this study was to characterize the role of the endothelium in angiotensin II-desensitization and its mechanisms of action. Rabbit aortic rings were exposed to increasing doses of angiotensin II (Ang II, 10(-9) to 2.5 x 10(-6)) to generate two cumulative dose-response curves (CDRC I and II). A 50-min interval separated CDRC I and II. Desensitization was observed at all doses in unrubbed aortic tissue and at lower doses in rubbed aortic tissue. Tachyphylaxis was greater in arteries with endothelium. Treatment of intact rings with L-N(G)-nitroarginine methyl ester (L-NAME, 10(-4) M) did not prevent this phenomenon. However, indomethacin (10(-5) M) and miconazol (10(-6) M) attenuated Ang II-desensitization. Treatment of unrubbed rings with nifedipine (10(-6) M) and cromakalim (10(-6) M) inhibited the effect of indomethacin. To confirm the involvement of K+ channels, unrubbed and rubbed aortic rings were treated with the K(Ca2+) blockers apamin (10(-7) M), tetraethylammonium (TEA, 10(-3) M), and iberiotoxin (10(-8) M), and the K(ATP) blocker glibenclamide (10(-5) M). In both arteries apamin, TEA, and glibenclamide abolished the tachyphylaxis without changes in the maximal response. Iberiotoxin diminished Ang II-desensitization in rubbed but not unrubbed arteries. Results from this study suggest that Ang II-desensitization involves endothelium-dependent and -independent mechanisms. Endothelium-dependent desensitization could be mediated by a cyclooxygenase-cytochrome P450 product, which could act by increasing K(Ca2+) channel activity.

[Cyclosporin A inhibits the response of osmotic water permeability to antidiuretic hormone in toad's bladder and to angiotensin II and antidiuretic hormone in toad's skin]. / La ciclosporina A inhibe la respuesta de la permeabilidad osmótica al agua a la hormona antidiurética en la vejiga del sapo y a la angiotensina II y hormona antidiurética en piel de sapo.

The purpose of the present study was to assess the effects of cyclosporine A (CyA) in the osmotic water flow response of isolated toad bladder to arginine-vasotocin (AVT) and to angiotensin II (Ang II) and AVT in isolated toad skin. CyA added to the dermal side of isolated toad skin or to the serosal side of toad bladder in concentrations of 0.42. 10(-6) M to 0.42. 10(-7) M had no effect on basal osmotic water permeability (Posm) but inhibited the hormonal response to AVT in both membranes (AVT 10(-10) M in toad bladder and 10(-8) to 10(-9) M in toad skin). CyA also inhibited the Posm response to Ang II (10(-7) M) in toad skin in concentrations of 0.42. 10(-6) M and 0.42. 10(-7) M. In toad bladder it could be demonstrated that the inhibitory effect was reversible. CyA in concentrations of 0.42. 10(-6) M inhibited the Posm response of toad skin to theophylline (3.2. 10(-3) M) and to dibutyryl cyclic AMP (6.3. 10(-3) M) suggesting an effect distal to the generation of cyclic AMP. These responses would support the possibility of a diuretic effect in the mammalian nephron.

Angiotensin-(1-7) increases osmotic water permeability in isolated toad skin.

Angiotensin-(1-7) (Ang-(1-7)) increased osmotic water permeability in the isolated toad skin, a tissue with functional properties similar to those of the distal mammalian nephron. Concentrations of 0.1 to 10 microM were effective, with a peak at 20 min. This effect was similar in magnitude to that of frog skin angiotensin II (Ang II) and oxytocin but lower than that of human Ang II and arginine-vasotocin. The AT2 angiotensin receptor antagonist PD 123319 (1.0 microM) fully inhibited the response to 0.1 microM Ang-(1-7) but had no effect on the response to Ang II at the same concentration. The specific receptor antagonist of Ang-(1-7), A-779, was ineffective in blocking the response to Ang-(1-7) and to frog skin Ang II. The AT1 receptor subtype antagonist losartan, which blocked the response to frog skin Ang II, was ineffective in blocking the response to Ang-(1-7). The present results support the view of an antidiuretic action of Ang-(1-7) in the mammalian nephron.

Angiotensin-(1-7) increases osmotic water permeability in isolated toad skin

Angiotensin-(1-7) (Ang-(1-7)) increased osmotic water permeability in the isolated toad skin, a tissue with functional properties similar to those of the distal mammalian nephron. Concentrations of 0.1 to 10 ÁM were effective, with a peak at 20 min. This effect was similar in magnitude to that of frog skin angiotensin II (Ang II) and oxytocin but lower than that of human Ang II and arginine-vasotocin. The AT2 angiotensin receptor antagonist PD 123319 (1.0 ÁM) fully inhibited the response to 0.1 ÁM Ang-(1-7) but had no effect on the response to Ang II at the same concentration. The specific receptor antagonist of Ang-(1-7), A-779, was ineffective in blocking the response to Ang-(1-7) and to frog skin Ang II. The AT1 receptor subtype antagonist losartan, which blocked the response to frog skin Ang II, was ineffective in blocking the response to Ang-(1-7). The present results support the view of an antidiuretic action of Ang-(1-7) in the mammalian nephron

Alcohol drinking and blood pressure among adolescents.

The purpose of this study was to evaluate alcohol consumption among adolescents from Tucuman, Argentina, and to determine its possible relationship with increased levels of blood pressure. Three hundred fifty-six students aged 13-18 included in the study were asked to answer questionnaires anonymously. Two blood pressures measures were then taken. Differences between both sexes were found in quantity and frequency of alcohol consumption. Enjoyment was determined to be the main reason for drinking. There was an association between frequency and alcohol-related problems, and smoking habits. There were also differences in blood pressure among males and females. A weak, but significant, relationship between quantity/frequency index and diastolic blood pressure was found. A greater prevalence of hypertension in male heavy drinkers was noted as well. Because this addiction implies multiple social problems and it also accounts for a hypertension risk factor, the importance of aiming at developing prevention strategies for alcohol abuse among adolescents is stressed.