Atrial Natriuretic Factor: Is It Responsible For Hyponatremia And Natriuresis In Neurosurgery?

To evaluate the presence of hyponatremia and natriuresis and their association with atrial natriuretic factor in neurosurgery patients. Methods: The study included 30 patients who had been submitted to intracranial tumor resection and cerebral aneurism clipping. Both plasma and urinary sodium and plasma atrial natriuretic factor were measured during the preoperative and postoperative time periods. Results: Hyponatremia was present in 63.33% of the patients, particularly on the first postoperative day. Natriuresis was present in 93.33% of the patients, particularly on the second postoperative day. Plasma atrial natriuretic factor was increased in 92.60% of the patients in at least one of the postoperative days; however, there was no statistically significant association between the atrial natriuretic factor and plasma sodium and between the atrial natriuretic factor and urinary sodium. Conclusion: Hyponatremia and natriuresis were present in most patients after neurosurgery; however, the atrial natriuretic factor cannot be considered to be directly responsible for these alterations in neurosurgery patients. Other natriuretic factors are likely to be involved.28215416

One sixth of Amazonian tree diversity is dependent on river floodplains

Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.Naturali

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees

Plasmatic Vasopressin In Patients Undergoing Conventional Infra-renal Abdominal Aorta Aneurysm Repair [vasopressina Plasmática Em Pacientes Submetidos à Correção De Aneurisma De Aorta Infrarrenal]

Objectives: To evaluate plasmatic arginine vasopressin (AVP) levels in patients undergoing scheduled conventional abdominal aortic aneurysm (AAA) repair. Methods: Plasmatic AVP concentrations were measured by radioimmunoassay in 22 non-consecutive adult patients undergoing infra-renal AAA repair. They were under combined general and epidural anesthesia at the following time frames: 1 - pre-operative (T0); 2 - 2h (T1) and 6h (T2) after the surgical procedure; 3 - in the morning at the first (T3), second (T4) and third (T5) post-operative days. Some clinical and laboratory variables were also recorded. Results: The mean age of patients was 68±10 years; 17 were males. Plasmatic AVP (mean±SD; pg/mL) was within the normal range at T0 (1.4±0.7; baseline), increasing significantly at T1 (62.6±62.9; P<0.001) and at T2 (31.5±49.7; P<0.001), with a progressive fall, returning to basal levels at T5 (2.1±3.8; P=NS). Positive and statistically significant correlations were found between AVP and glycemia, serum lactate and white blood cells counts, but not with systemic arterial pressure or plasma osmolarity during the postoperative period. Conclusions: Considering that no correlations were found between AVP levels and hemodynamic or plasmatic osmolarity variations in AAA repair, it seems that stress response is mainly secondary to noxious stimulation mediated by the autonomic nervous system that is not completely blocked by anesthetics. Descriptors: Intensive care units. Cardiovascular abnormalities. 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A necropsy study (1992) Eur J Surg., 158 (1), pp. 19-23Saadi, E.K., Gastaldo, F., Dussin, L.H., Zago, A.J., Barbosa, G., Moura, L., Tratamento endovascular dos aneurismas de aorta abdominal: Experiência inicial e resultados a curto e médio prazo (2006) Rev Bras Cir Cardiovasc., 21 (2), pp. 211-216Chen, J.M., Cullinane, S., Spanier, T.B., Artrip, J.H., John, R., Edwards, N.M., Vasopressin deficiency and pressor hypersensitivity in hemodynamically unstable organ donors (1999) Circulation., 100 (19 SUPPL.), pp. II244-II246Cintra, E.A., McIel Jr., J.A., Araújo, S., Castro, M., Martins, E.F., Falcão, A.L., Vasopressin serum levels in patients with severe brain lesions and in brain-dead patients (2004) Arq Neuropsiquiatr., 62 (2 A), pp. 226-232Lee, W.J., Choo, Y.E., Song, W.Y., Lee, J.C., Kim, K.T., Lee, S.H., Responses of vasopressin release in patients with cardiopulmonary bypass anesthetized with enflurane and morphine (1989) J Korean Med Sci., 4 (2), pp. 71-76Goldmann, A., Hoehne, C., Fritz, G.A., Unger, J., Ahlers, O., Nachtigall, I., Combined vs. Isoflurane/Fentanyl anesthesia for major abdominal surgery: Effects on hormones and hemodynamics (2008) Med Sci Monit., 14 (9), pp. CR445-CR452Donald, R.A., Perry, E.G., Wittert, G.A., Chapman, M., Livesey, J.H., Ellis, M.J., The plasma ACTH, AVP, CRH and catecholamine responses to conventional and laparoscopic cholecystectomy (1993) Clin Endocrinol (Oxf)., 38 (6), pp. 609-615Winterhalter, M., Brandl, K., Rahe-Meyer, N., Osthaus, A., Hecker, H., Hagl, C., Endocrine stress response and inflammatory activation during CABG surgery. A randomized trial comparing remifentanil infusion to intermittent fentanyl (2008) Eur J Anaesthesiol., 25 (4), pp. 326-335Toivonen, J., Plasma renin, catecholamines, vasopressin and aldosterone during hypotension induced by labetalol with isoflurane (1991) Acta Anaesthesiol Scand., 35 (6), pp. 496-501Kruimel, J.W., Pesman, G.J., Sweep, C.G., van der Vliet, J.A., Liem, T., Jansen, J.B., Depression of plasma levels of cytokines and ex-vivo cytokine production in relation to the activity of the pituitary-adrenal axis, in patients undergoing major vascular surgery (1999) Cytokine., 11 (5), pp. 382-388Anderson, P.L., Arons, R.R., Moskowitz, A.J., Gelijns, A., Magnell, C., Faries, P.L., A statewide experience with endovascular abdominal aortic aneurysm repair: Rapid diffusion with excellent early results (2004) J Vasc Surg., 39 (1), pp. 10-19Morgenthaler, N., Struck, J., Jochberger, S., Dünser, M.W., Copeptin: Clinical use of a new biomarker (2008) Trends Endocrinol Metab., 19 (2), pp. 43-49Jochberger, S., Zitt, M., Luckner, G., Mayr, V.D., Wenzel, V., Ulmer, H., Postoperative vasopressin and copeptin levels in noncardiac surgery patients: A prospective controlled trial (2009) Shock., 31 (2), pp. 132-13

Characterization of the acute pancreatitis induced by secretory phospholipases A(2) in rats

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOAcute pancreatitis (AP) is an inflammatory disease of the pancreas characterized by local inflammation and extrapancreatic effects such as lung injury. Secretory phospholipases A(2) (PLA(2)s) have been implicated in triggering AP, but their exact role to evoke AP is largely unknown. Therefore, we have tested the ability of sPLA(2)s to induce AP in rats, using venom sPLA(2)s with residual or high enzymatic activity (bothropstoxin-II and Naja mocambique mocambique venom PLA(2), respectively), as well as sPLA(2) devoid of catalytic activity (piratoxin-I). The injection of Naja m. mocambique venom PLA(2), bothropstoxin-II or piratoxin-I (300 mu g/kg each) into the common bile duct increased significantly the pancreatic plasma extravasation and myeloperoxidase activity. The lung myeloperoxidase and serum amylase were also increased for all groups, although the Naja mocambique mocambique venom PLA(2) induced higher lung myeloperoxidase and serum amylase values, compared with piratoxin-I and/or bothropstoxin-II. Histopathology of pancreas and lungs in piratoxin-I-injected rats showed interstitial oedema in both tissues, and neutrophil infiltration with acinar cell necrosis in pancreas. In conclusion, sPLA(2)s induce AP in rats and the catalytic activity is not essential to induce the local effects in pancreas, although it appears to contribute partly to the remote lung injuryPergamon Press468921926FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOsem informaçãoOxfor