Silvia R. Souza
University of São Paulo
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The Journal of Experimental Biology | 2004
Silvia R. Souza; José Eduardo de Carvalho; Augusto Shinya Abe; J.E.P.W. Bicudo; Marilene S. C. Bianconcini
SUMMARY The tegus increase in body mass after hatching until early autumn, when the energy intake becomes gradually reduced. Resting rates of oxygen consumption in winter drop to 20% of the values in the active season (V̇O2=0.0636 ml g-1 h-1) and are nearly temperature insensitive over the range of 17-25°C (Q10=1.55). During dormancy, plasma glucose levels are 60% lower than those in active animals, while total protein, total lipids and β-hydroxybutyrate are elevated by 24%, 43% and 113%, respectively. In addition, a significant depletion of liver carbohydrate (50%) and of fat deposited in the visceral fat bodies (24%) and in the tail (25%) and a slight loss of skeletal muscle protein (14%) were measured halfway through the inactive period. Otherwise, glycogen content is increased 4-fold in the brain and 2.3-fold in the heart of dormant lizards, declining by the onset of arousal. During early arousal, the young tegus are still anorexic, although V̇O2 is significantly greater than winter rates. The fat deposits analysed are further reduced (62% and 45%, respectively) and there is a large decrease in tail muscle protein (50%) together with a significant increase in glycogen (2-3-fold) and an increase in plasma glucose (40%), which suggests a role for gluconeogenesis as a supplementary energy source in arousing animals. No change is detectable in citrate synthase activity, but β-hydroxyacyl CoA dehydrogenase activities are strongly affected by season, reaching a 3-fold and 5-fold increase in the liver tissue of winter and arousing animals, respectively, and becoming reduced by half in skeletal muscle and heart of winter animals compared with late fall or spring active individuals. From hatching to late autumn, the increase of the fat body mass relatively to body mass is disproportionate (b=1.44), and the mass exponent changes significantly to close to 1.0 during the fasting period. The concomitant shift in the V̇O2 mass exponent in early autumn (b=0.75) to values significantly greater than 1.0 in late autumn and during winter dormancy indicates an allometric effect on the degree of metabolic depression related to the size of the fat stores and suggests greater energy conservation in the smaller young.
Journal of the American College of Cardiology | 2010
Caio Julio Cesar Fernandes; Carlos Vianna Poyares Jardim; Andre Hovnanian; Susana Hoette; Bruno Arantes Dias; Silvia R. Souza; Marc Humbert; Rogério Souza
OBJECTIVES The objective of this study was to evaluate the natural history of untreated schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) patients as compared to idiopathic pulmonary arterial hypertension (IPAH) with respect to hemodynamics recorded at presentation and 36 months survival. BACKGROUND Schistosomiasis (Sch) is one of the most prevalent chronic infectious diseases in the world. Nevertheless data regarding one of its most severe clinical complications, pulmonary arterial hypertension (PAH), is scarce. METHODS We retrospectively analyzed case notes of all consecutive patients diagnosed of Sch-PAH and IPAH referred to the Heart Institute in São Paulo, Brazil, between 2004 and 2008. None of the Sch-PAH received PAH specific treatment whereas all IPAH patients did. RESULTS Sch-PH patients (n = 54) had less severe pulmonary hypertension as evidenced by lower levels of pulmonary vascular resistance (11.3 +/- 11.3 W vs. 16.7 +/- 10.6 W; p = 0.002) and mean pulmonary artery pressure (56.7 +/- 18.7 mm Hg vs. 64.6 +/- 17.4 mm Hg; p = 0.01) and higher cardiac output (4.62 +/- 1.5 l/min vs. 3.87 +/- 1.5 l/min; p = 0.009) at presentation than IPAH patients (n = 95). None of the Sch-PAH patients demonstrated a positive response to acute vasodilator testing, whereas 16.2% of IPAH patients did (p = 0.015). Survival rates at 1, 2, and 3 years were 95.1%, 95.1%, and 85.9% and 95%, 86%, and 82%, for Sch-PAH and IPAH, respectively (p = 0.49). Both groups had a higher survival rate when compared to IPAH survival as estimated by the NIH equation (71%, 61%, and 52%, respectively). CONCLUSIONS Sch-PAH has a more benign clinical course than IPAH despite a lack of demonstrable acute vasoreactivity at hemodynamic evaluation.
Journal of Chromatography A | 1998
Silvia R. Souza; Marina F. M. Tavares; Lilian R. F. Carvalho
Abstract Strategies for method development and optimization of conditions in ion chromatography (IC) and capillary electrophoresis (CE) are proposed. The approaches are based on well established theoretical models for analyte elution and rely on the inspection of effective capacity factor versus specific gradient ramp slope curves for IC and effective mobility versus pH curves for CE. Commonly used IC eluent systems, such as sodium hydroxide and sodium borate, and the CE electrolyte 3,5-dinitrobenzoic acid were investigated. A standard aqueous solution containing formate, acetate, α-hydroxyacetate (glycolate), propionate, α-hydroxypropionate (lactate), butyrate and β-hydroxybutyrate anions was used to test the analytical conditions indicated by the models. Among the IC eluent systems, borate presented a better separation performance than hydroxide. However, a complete resolution of all components in the standard mixture was not accomplished experimentally at the chosen gradient ramp slope of 0.05 mM/ml. The analyte pairs acetate/lactate and glycolate/butyrate, whose effective capacity factors differ by approximately 0.2 units, co-eluted at 0.17 and 0.24 resolution, respectively, and the retention time of the last eluting analyte was relatively long (20 min). Nevertheless, the IC method provided the best overall limit of detection (LOD; 0.016–0.082 mg/l). Under the optimized CE conditions, all seven components in the standard mixture were resolved satisfactorily in less than 7 min. The analyte pair β-hydroxybutyrate/butyrate presented the worst resolution, 0.45, and a difference in effective mobility of 1.6%. The CE methodology provided the best column efficiency, roughly a ten-fold improvement in terms of number of plates per meter over the IC method, but the limit of detection was comparatively poorer (0.050–0.36 mg/l). Both proposed IC and CE methodologies can be applied to the analysis of mono- and hydroxycarboxylic acids in samples of environmental interest, providing complementary information. The choice of the most appropriate method is a compromise between chemical composition of the sample and concentration level of the analytes under investigation. For instance, the classical co-elution of acetate/lactate that occurs in IC columns, can be solved by CE. But the CE method may lack sensitivity for these analytes, which compromises the analysis of certain real samples. The LOD for acetate and lactate as determined by IC is 0.036 and 0.082 mg/l, respectively, while for CE they increase to 0.11 and 0.20 mg/l. Under optimum conditions, the separation and identification of mono- and hydroxycarboxylic acids in an atmospheric particulate matter sample is illustrated by both techniques.
Comparative Biochemistry and Physiology Part A: Physiology | 1986
John C. McNamara; Gloria S. Moreira; Silvia R. Souza
Abstract 1. 1. The effect of acute salinity exposure (0, 7, 14, 21, 28 and 35%.S) on the respiratory metabolism of selected ontogenetic stages (zoeae, postlarvae and adults) of the freshwater shrimp Macrobrachium olfersiiwas examined. 2. 2. Metabolic rates are salinity independent from 14 to 28%. S in zoeae 1–4, but tend to increase with increasing salinity in zoeae 5 and 8. Postlarvae exhibit maximal rates in midrange salinities while in adult shrimps, oxygen consumption rates decrease with salinity increase. 3. 3. Salinity has little effect on the metabolism-weight relationship, regression analysis indicating that b varies from 0.69 in 0%. S to 0.62 in 35%. S. 4. 4. Data are discussed as to whether larval responses reflect adaptation to the adult biotope and whether development of the larval neurosecretory system might affect metabolic response to salinity exposure.
Chest | 2012
Caio Julio Cesar Fernandes; Bruno Arantes Dias; Carlos Vianna Poyares Jardim; Andre Hovnanian; Susana Hoette; Luciana Tamie Kato Morinaga; Silvia R. Souza; Milena Suesada; Ana Paula Breda; Rogério Souza
BACKGROUND Schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) may be one of the most prevalent forms of pulmonary arterial hypertension (PAH) worldwide. However, the clinical and hemodynamical response to specific PAH therapy in Sch-PAH is not known. METHODS We retrospectively analyzed the charts of all patients with Sch-PAH who initiated specific PAH treatment between June 2003 and June 2010 in a single PAH reference center in São Paulo, Brazil. Clinical and hemodynamical data were retrospectively collected and evaluated in two periods: baseline and posttreatment. RESULTS The study population consisted of 12 patients with Sch-PAH. They were treated with phosphodiseterase-5 inhibitors (seven patients), endothelin receptor antagonists (four patients), or combination therapy (one patient). Mean treatment period was 34.9 ± 15.5 months. Patients with Sch-PAH presented significant improvements in terms of functional class, 6-min walk test distance (439 ± 85 to 492 ± 79 m, P = .032), cardiac index (2.66 ± 0.59 to 3.08 ± 0.68 L/min/m(2), P = .028), and indexed pulmonary vascular resistance (20.7 ± 11.6 to 15.9 ± 9 W/m(2), P = .038) with the introduction of specific PAH treatment. CONCLUSIONS We conclude that specific PAH therapy may be of benefit to patients with Sch-PAH, considering clinical, functional, and hemodynamic parameters.
Journal of the Brazilian Chemical Society | 2001
Silvia R. Souza; Lilian R. F. Carvalho
Ambient levels and diurnal profiles of formic and acetic acids were measured in the atmosphere of Sao Paulo City in winter and spring 1996. A comparison between two different urban sites was done. Results demonstrate that carboxylic acid levels were affected by seasonality in the site with high vehicular emission density, while no seasonal influence was observed for the other site studied. Ranges of mixing ratios from 0.64 to 11.8 ppbv for formic acid and 0.51 to 10.7 ppbv for acetic acid were recorded. The results concerning the carboxylic acid concentrations were discussed with respect to direct emission and in situ photochemical production.
Journal of Crustacean Biology | 1996
Michele G. Wheatly; Silvia R. Souza; Mary K. Hart
ABSTRACT The relationships between hemolymph acidic-basic equivalents (pH, PCO2, and [HCO3, + C032-]), electrolytes (Na, K, Ca, Mg, and Cl), and ecdysone concentration were investigated in the crayfish Procambarus clarkii at 23°C during extracellular acidosis resulting from: (1) 24-h aerial exposure, (2) 96-h hyperoxic exposure (PO2 > 550 mm Hg), or (3) 96-h acid exposure (pH 4.0). A control series failed to reveal any significant effects of repetitive hemolymph sampling. In air, crayfish developed an initial (3-h) respiratory acidosis that was completely compensated within 24 h by metabolic base [HCO3 + CO32 ] accumulation. Circulating Ca and Cl both decreased at 24 h, while K increased. In this case, there was evidence that acid-base balance was corrected by ion exchange with the intracellular compartment. Hyperoxia was characterized by an initial (3-h) respiratory acidosis followed by a metabolic acidosis. The combined acidosis remained uncompensated, and circulating ecdysone decreased after 24 h. Acid exposure produced a purely metabolic acidosis that was partially corrected by a respiratory alkalosis between 48 and 72 h and was accompanied by an increase in circulating ecdysone. Ca and K decreased. Collectively, the experiments established a relationship between extracellular ecdysone and pH. Meanwhile, Ca remained relatively constant in all 3 treatments.
Química Nova | 1997
Silvia R. Souza; Lilian R. F. Carvalho
In this work, analytical strategies are evaluated in order to measure accurately the ambient levels of atmospheric organic acids. Environmental considerations about the determination of low molecular weight mono- and di-carboxylic acids from urban areas of Sao Paulo are described.
Brazilian Journal of Botany | 2002
Silvia R. Souza; Pérola de Castro Vasconcellos; Waldir Mantovani; Lilian R. F. Carvalho
A vegetacao e a fonte de aproximadamente 90% de todos os compostos orgânicos volateis na atmosfera global. Alguns hidrocarbonetos oxigenados emitidos por plantas reagem com radicais livres, tais como nitrato e hidroxila, e ozonio em taxas comparaveis com aquelas dos compostos antropogenicos mais reativos e podem contribuir para a formacao de ozonio em areas urbanas. Apesar do papel importante dos hidrocarbonetos naturais na formacao fotoquimica dos oxidantes, pouco se sabe sobre as especies quimicas dos compostos orgânicos volateis emitidos por plantas. Nesse trabalho, foi estudada a emissao de compostos orgânicos volateis por Ficus benjamina, especie comumente encontrada na regiao da cidade de Sao Paulo. Os gases emitidos pelas folhas da F. benjamina foram coletados em sistemas fechados e varios compostos orgânicos volateis oxigenados, tais como acidos orgânicos (acido formico e acido acetico), aldeidos (formaldeido, acetaldeido e hexanal) e alcoois (mentol, 1- butanol, 1-pentanol, 2-penten-1-ol, 4-penten-2-ol e linalool), foram identificados atraves de tecnicas cromatograficas.
Ultrasonics | 1998
Silvia R. Souza; M. Korn; L.R.F. de Carvalho; M.G.A. Korn; Marina F. M. Tavares
Abstract Sonochemical degradation of a metal in aqueous solution with ultrasound has been studied. Chemical effects in the heterogeneous system were evaluated and relationships between formed and consumed species during the sonication process were established statistically, employing factor analysis. Chemical species, such as hydrogen peroxide, nitrate, nitrite and zinc species were generated in a single heterogeneous zinc-water system under ultrasonic irradiation and their concentrations were determined. Different times of irradiation exposure were employed and the composition of the irradiated solution was monitored by ion chromatography (IC), inductively coupled plasma atomic emission spectrometry (ICP-AES) and capillary electrophoresis (CE) techniques. Variations of the hydrogen ion and hydrogen peroxide concentrations were measured by potentiometric and spectrophotometric methods, respectively. The global covariance matrix of the variables was built from experimental data, including irradiation time, nitrite, nitrate, zinc and hydrogen peroxide concentrations, and pH variation. Based on the monitoring of species formed in sonicated solutions and the multi-parametric evaluation obtained from the covariance matrix, some correlation related to the formed and consumed species is shown. Nitrate, nitrite, zinc and hydrogen peroxide formation in aqueous solution is strongly dependent upon the irradiation exposure time. Furthermore, the pH increases slightly as the amount of nitrate and nitrite ions becomes constant. This later observation confirms the concept that hydrogen ions are consumed when nitrate and nitrite ions are formed. The pH increase during sonication of the zinc/water system reveals a rather different behavior when compared to the sonicated single pure water system. At the same sonication stage that nitrate and nitrite concentrations become practically constant, zinc concentration increases as hydrogen peroxide concentration increases. According to these observations, some chemical processes can be proposed. Hydrogen ions generated in sonicated solution are consumed by nitrate and nitrite ions formation. Hydrogen ions and hydrogen peroxide formed during sonication might react with metallic fragments originated eventually from corrosive action of the ultrasound. Zinc hydroxo-complexes are formed predominantly by hydroxyl ions generated during hydrogen peroxide reduction. On a smaller proportion, zinc hydroxo-complexes may be also formed due to the alkaline medium generated during hydrolysis of zinc ions.