Showing papers by "University of São Paulo published in 1987"

Condições hidrográficas na plataforma continental ao largo de Ubatuba: variações sazonais e em média escala

Abstract: As caracteristicas hidrograficas da regiao ao largo de Ubatuba, pesquisadas em periodos quase-sinoticos de verao (dezembro, 1985) e de inverno (julho, 1986), mostraram padroes distintos de distribuicao de massas de agua. Dois dominios com caracteristicas fisicas diferentes foram identificados sobre a plataforma continental: um interior e costeiro, e outro exterior, separados por uma zona frontal bem definida pelo campo de temperatura para o inverno. O dominio interior tem, durante o verao, uma estraficacao de massa em duas camadas, determinada principalmente pelo desenvolvimento da termoclina sazonal nesta epoca do ano, enquanto que no inverno a estratificacao dessa regiao e bem mais homogenea. No verao a camada superficial (profundidades menores do que 20 m) de toda a regiao e ocupada basicamente pela Agua Costeira (AC), que se mistura com a Agua Tropical (AT) mais ao largo; nesta epoca do ano observa-se, na camada subsuperficial, predominância da Agua Central do Atlântico Sul (ACAS), cuja mistura vertical com a AC e somente observada nas proximidades da costa. No inverno a ACAS nao penetra muito sobre a plataforma continental, e na camada superficial ocorre uma intrusao acentuada de AT no dominio exterior, sendo o dominio interior ocupado principalmente pela AC, a qual interage com a ACAS apenas na zona frontal que delimita a regiao de ocorrencia dessas massas de agua. Com base nesses padroes de distribuicao de massas de agua e do campo de massas, bem como nas condicoes meteorologicas de regiao vizinha, e sugerido um modelo de circulacao cuja dinâmica e controlada pelo vento e pela acao da Corrente do Brasil. Essa acao da Corrente do Brasil sobre o dominio exterior e, provavelmente, responsavel pela presenca dos vortices com caracteristicas de vortices frontais observados nas duas epocas do ano. Esses vortices, cuja extensao horizontal nas profundidades de 25 e 50 m e bem definida nas estruturas termica e halina, tem provavelmente um importante papel na troca de massas de agua entre a costa e o talude, contribuindo para o enriquecimento das aguas da plataforma continental atraves dos movimentos ascendentes que ocorrem em seu nucleo.

Effect of chlorimipramine and maprotiline on experimental anxiety in humans.

Abstract: In order to assess the role played by serotonin (5-HT) and noradrenaline in anxiety, four groups of healthy volunteers were given 25 mg of the selective inhibitor of 5-HT uptake chlorimipramine, 50 mg of the selective inhibitor of noradrenaline uptake maprotiline, 1 mg of the benzodiazepine anxiolytic lorazepam or placebo, and submitted to a simulated public speaking (SPS) test, consisting of speaking in front of a videocamera. Subjective anxiety was evaluated by the visual analog mood scale (VAMS) of Norris as well as by the state-trait anxiety inventory (STAI) of Spielberger. Chlorimipramine enhanced SPS-induced anxiety, whereas maprotiline and lorazepam reduced anxiety during as well as outside the test period. Mental and physical sedation (VAMS) were increased by either maprotiline or lorazepam. In a scale of bodily symptoms, chlorimipramine tended to increase muscle tension, agitation and palpitation, whereas maprotiline caused lethargy. The rise in blood pressure induced by the SPS procedure outlast...

Hyperosmotic sodium salts reverse severe hemorrhagic shock: other solutes do not.

Abstract: Severe hemorrhage in pentobarbital-anesthetized dogs (25 mg/kg) is reversed by intravenous NaCl (4 ml/kg, 2,400 mosmol/l, 98% long-term survival). This paper compares survival rates and hemodynamic and metabolic effects of hypertonic NaCl with sodium salts (acetate, bicarbonate, and nitrate), chlorides [lithium and tris(hydroxymethyl)aminomethane (Tris)], and nonelectrolytes (glucose, mannitol, and urea) after severe hemorrhage (44.5 +/- 2.3 ml/kg blood loss). Sodium salts had higher survival rates (chloride, 100%; acetate, 72%; bicarbonate, 61%; nitrate, 55%) with normal stable arterial pressure after chloride and nitrate; near normal cardiac output after sodium chloride; normal acid-base equilibrium after all sodium salts; and normal mean circulatory filling pressure after chloride, acetate, and bicarbonate. Chlorides and nonelectrolytes produced low survival rates (glucose and lithium, 5%; mannitol, 11%; Tris, 22%; urea, 33%) with low cardiac output, low mean circulatory filling pressure, and severe metabolic acidosis. Plasma sodium, plasma bicarbonate, mean circulatory filling pressure, cardiac output, and arterial pressure correlated significantly with survival; other parameters, including plasma volume expansion or plasma osmolarity, did not. It is proposed that high plasma sodium is essential for survival.

The role of gas exchange in the inorganic carbon, oxygen, and 222Rn budgets of the Amazon River'

Abstract: Dissolved oxygen, ***Rn, pC02, alkalinity, respiration rate, and discharge have been measured at eight mainstem and seven tributary stations during February-March 1984 in a 1,700-km stretch of the Amazon River between Vargem Grande and Obidos in Brazil. Air-water gas exchange rates were estimated two ways: measurements of the flux of 222Rn into floating domes yielded an average boundary layer thickness of 78 pm, and oxygen mass balance calculations resulted in an average of 38 pm. Given a boundary layer thickness on the order of 50 pm, CO, loss to the atmosphere in the entire reach would have been 37.4 kmol s-l, which is about equal to the total tributary dissolved inorganic carbon (DIC) input (43 kmol s-l) and is about half of the total fluvial DIC input to the section (97.7 kmol s-l). Thus, CO, evasion is a major component of Amazon River DIC balance. Because gas exchange within the section was rapid relative to water travel time through the section, a quasi-steady state was maintained between respiratory input and evasion of CO,. Dissolved ***Rn activities in the mainstem varied from 3.5 to 8.3 dpm liter-’ and were always highly supersaturated with respect to the atmosphere. Dissolved radon was also not supported by decay ~f~*~Ra (0.59-0.70 dpm liter-‘) in the mainstem. A ***Rn mass balance indicated that direct groundwater input into this stretch of the Amazon mainstem probably accounted for no more than 1% of water discharge.

Inhibition of Leukocyte Chemotaxis by Factor in Alloxan-Induced Diabetic Rat Plasma

Abstract: The early local exudative cellular reaction in an inflammatory lesion was impaired in alloxan-induced diabetic rats due to reduced migration of neutrophils to the inflamed area. Neutrophils, however, were capable of moving from reserve compartments into blood in these animals. Furthermore, the functional integrity of their surface membranes, assessed by the capacity of the cells to adhere to nylon fiber, was not altered by alloxan diabetes. An intrinsic cellular defect also did not occur, because the cells were capable of responding to chemotactic stimuli in the Boyden chamber system, provided they were suspended in Eagle's medium or normal serum. Suspended in the corresponding diabetic serum, a blockade of the chemotactic response was observed. Increasing concentrations of diabetic serum, added to a suspension containing neutrophils collected from normal donors, progressively inhibited the response of the cells to a chemotactic stimulus. Hyperglycemia alone or hyperosmolality secondary to hyperglycemia, the presence of ketone bodies, or a direct effect of alloxan did not explain the results. In addition, the capacity to generate chemotactic factors remained intact in diabetic serum. Pretreatment of the diabetic animals with insulin resulted in a gradual recovery of the chemotactic response in vivo and in vitro. We conclude that alloxan-induced diabetic rat serum contains a substance that inhibits neutrophil chemotaxis and that insulin administration is essential for the clearance of this substance from plasma.

Estudo das condições de saúde das crianças no Município de São Paulo, SP (Brasil), 1984-1985: V - Anemia

Abstract: Dentro de estudo populacional sobre condicoes de saude na infância, uma amostra representativa das criancas menores de cinco anos do Municipio de Sao Paulo, Brasil (n = 912) foi estudada quanto a prevalencia e distribuicao da anemia. A frequencia de criancas anemicas (concentracao de hemoglobina < 11g/dl) foi de 35,6%, sendo de 14,7% a frequencia de casos severos (hemoglobina < 9,5g/dl). As maiores prevalencias de anemia se concentraram na faixa etaria de 6 a 24 meses de idade, onde mais da metade das criancas se mostraram anemicas e cerca de metade dos casos corresponderam a formas severas da deficiencia. Embora a prevalencia da anemia tenda a diminuir com a melhoria do nivel socioeconomico da populacao, nao se detectaram estratos da populacao imunes a deficiencia. Em comparacao a situacao observada no Municipio ha cerca de dez anos, verifica-se elevacao expressiva da prevalencia da anemia: mais de 50% para o total de casos e mais de 100% para as formas severas da deficiencia. O conjunto das informacoes geradas pelo estudo epidemiologico realizado em 1984/85 sugere que a anemia na infância no Municipio de Sao Paulo esteja relacionada basicamente a caracteristicas desfavoraveis da alimentacao infantil, sendo menos relevante o papel que poderia ser atribuido as parasitoses intestinais.

The Role of Glucocorticoids in the Stress-Induced Reduction of Extrathyroidal 3,5,3′-Triiodothyronine Generation in Rats*

Abstract: Serum concentrations of T4, T3, and rT3 as well as liver and kidney 5'-deiodinase activity, have been examined in rats stressed by restraint. After immobilization, serum concentrations of T3 decreased significantly (6 hr, -33 +/- 1%; 8 h, -42 +/- 3%), while serum rT3 increased (6 h, +55 +/- 3%; 8 h, +75 +/- 5%). In the same or similarly treated animals, there was a time-dependent reduction in T4 5'-deiodinase activity in both liver (4 h, -23 +/- 2%; 8 h, -43 +/- 3%) and kidney (4 h, -18 +/- 1%; 8 h, -42 +/- 3%) homogenates. The reduction in hepatic and renal T3 production was due to reduced enzyme activity and not to reduced substrate availability. In spite of reductions in serum TSH (4 h, -9 +/- 1%; 8 h, -51 +/- 5%), the serum T4 concentration did not fall. The serum concentration of corticosterone reached 30 times the basal level after 8 h of restraint. Either adrenalectomy or metyrapone treatment, followed by replacement with nonstress doses of B, completely prevented the alterations of iodothyronine metabolism induced by restraint. These results indicate that the stress-induced elevation of plasma glucocorticoids plays a key role in the pathogenesis of the low T3 syndrome in this model. The reduction in serum T3 may be accounted for by a reduction in T3 production by liver and kidney, adding support to the concept that these organs are an important source of plasma T3 in the rat.

Estudos em sempre-vivas: importância econômica do extrativismo em Minas Gerais, Brasil

Abstract: The present work is a study of "everlasting flowers" as a natural product of importance for interior decoration. The term "everlasting flowers" is used for scapes and inflorescences which, even after being detached from the plant, still maintain the appearance of living structures. The economic activities related to this group of plants are considered; their importance is demonstrated, as a source of income and employment in the region of Diamantina (State of Minas Gerais, Brazil), and also as a source of revenue for the country: production is largely exported to Europe and the U.S.A. A survey was made of the quantity of such flowers marketed, of prices paid to collectors, and of the wholesale prices of the species most extensively commercialized in the region (18 Eriocaulaceae, 10 Gramineae, 3 Xyridaceae and 2 Cyperaceae); from these figures were calculated the values involved in production and commercialization, thus providing some idea of the income created and the quantity of plants concerned. The importance of exportation of everlasting flowers as a source of revenue was also considered. Analysis of data permits inference of a decline in export; this may be due to a fall in production as a result of over-collection and subsequent difficulty in recuperation of populations, or of market competition from other countries. It is suggested that research should be increased with a view to making viable the systematic cultivation of those species which can be cultivated, as an important contribution to the economy of regions of campo rupestre

Iron-mediated induction of sister-chromatid exchanges by hydrogen peroxide and superoxide anion.

Abstract: When Chinese hamster fibroblasts were exposed to hydrogen peroxide or to a system consisting of xanthine oxidase and hypoxanthine, which generates superoxide anion plus hydrogen peroxide, sister-chromatid exchanges (SCEs) were formed in a dose-dependent manner. When the iron-complexing agent o-phenanthroline was present in the medium, however, the production of these SCEs was completely inhibited. This fact indicates that the Fenton reaction: Fe2+ + H2O2 → OH0 + OH− + Fe3+ is responsible for the production of SCEs. When O2− and H2O2 were generated inside the cell by incubation with menadione, the production of SCE was prevented by co-incubation with copper diisopropylsalicylate, a superoxide dismutase mimetic agent. The most likely role of O2− is as a reducing agent of Fe3+: O2− + Fe3+ → Fe2+ + O2, so that the sume of this and the Fenton reaction, i.e., the iron-catalyzed Haber—Weiss reaction, provides and explanation for the active oxygen species-induced SCE: SCE: H2O2 + O2− → OH− + OH0 + O2. Accorrding to this view, the OH radical thus produced is the agent which ultimately causes SCE. These results are discussed in comparison with other mechanisms previously proposed for induction of SCE by active oxygen species.

Heart transplantation in patients with Chagas' disease cardiomyopathy.

Abstract: Among 26 heart transplant patients, four had Chagas' disease cardiomyopathy. They were male patients, aged 28 to 43 years; three were in New York Heart Association class IV, and one was in class II but with refractory arrhythmias. The immunosuppressive protocol was cyclosporine and steroids in the first patient, and cyclosporine, azathioprine, and steroids in the last patient. Three patients had one or more rejection episodes, and one had none. One patient had a lymphoproliferative intestinal disease. Three patients had a new acute phase of Chagas' disease in postoperative days 59, 81, and 420, with fever, skin lesions, and myocarditis. The Trypanosoma cruzi was found in skin lesions in all three patients and in the myocardial biopsy in two patients. The laboratory tests did not show the expected results for the acute phase. All the alterations were reversed by specific therapy in a few days. One patient died on postoperative day 197 from rejection, and the immunosuppression was diminished because of the lymphoproliferative disease; the others were well 107, 160, and 500 days after the transplantation. The conclusions were as follows: (1) It seems that steroid pulse therapy predisposes the patient to a new acute phase of Chagas' disease. (2) Clinical presentation and laboratory test results of the acute phase are not the usual. (3) Specific drug therapy reverses all the alterations of this acute phase in a few days. (4) Although additional care is necessary and specific complications are expected, heart transplantation can be done with good results in patients with Chagas' cardiomyopathy.

Cardiovascular involvement in human and experimental leptospirosis: pathologic findings and immunohistochemical detection of leptospiral antigen.

Abstract: Twenty hearts from patients dying of leptospirosis were studied. Interstitial myocarditis was found in 50% of the cases, and a significant statistical correlation was observed between myocarditis and the inflammatory involvement of the conduction tissue. Acute coronary arteritis, affecting the main branches of the coronary arteries, was observed in 70% of the cases, and this finding also correlates significantly with interstitial myocarditis. Aortitis was found in 57.8% of the cases. When serum against L. interrogans serovar icterohaemorrhagiae was used, focal IP antigen deposits were observed in the coronary arteries and in the aorta. Experimental data from 12 guinea-pigs inoculated with L. interrogans serovar icterohaemorrhagiae showed a focal myocarditis involving mainly the subendocardial and pericoronary heart tissue, with IP antigen deposits in the same sites. Leptospirosis might be visualized as a generalized illness resembling other infectious vasculitides. The heart and main vessels are involved during the septicaemic phase of the disease, and bacterial migration, toxin(s), enzymes and/or antigenic products liberated by bacterial lysis might account for the increased endothelial permeability with antigen deposits and inflammation.

Regulation of the trehalose-6-phosphate synthase complex in Saccharomyces. I. Interconversion of forms by phosphorylation.

Abstract: Trehalose-6-phosphate synthase is another example of an enzyme of carbohydrate metabolism, in Saccharomyces, which could be regulated by interconversion of forms. Deactivation was mediated both in vivo and in vitro by a cyclic AMP-dependent protein kinase. Reversibility of this process was obtained by a phosphatase treatment leading to an increase in activity. The phosphorylated, less active form of the enzyme proved to be more susceptible to activation by ATP.Mg. Mutants with well defined lesions in the cyclic AMP-dependent protein kinase system were used to corroborate our findings of a possible regulatory mechanism of trehalose-6-phosphate synthase activity by interconversion of forms.

A two-process theory of the response to size and distance.

Abstract: Evidence for a two-process theory of the observer’s visual judgment of size and distance is summarized and evaluated. The primary process, as expressed by the size-distance invariance hypothesis (SDIH), concerns the interrelation of perceived size (S’) and perceived distance (D’), independent of information derived from memory or suggestion. The secondary process involves information regarding size (from memory or suggestion) not contained in the immediate visual stimulus. If the primary and secondary sources of size information differ, the object is seen as off-sized. This off-sized perception can be used to modify the direct report of the distance of the object. In the case of the casual suggestion of size, the off-sized judgment produces a nonperceptual (cognitive) report of distance (Gogel, 1981b). In the case of the memory of the size of a familiar object, some of the effect on the direct report of perceived distance is perceptual, but most is cognitive (Gogel, 1976). In the case of optical expansion, the effect of off-sized judgments on distance responses produces a clear modification of perceived distance (Swanston & Gogel, 1986). The experimental distinction between primary and secondary processes is facilitated by comparing measures of perceived distance obtained from direct procedures (e.g., verbal reports of distance) with those obtained from indirect procedures (e.g., the head motion procedure). The former (direct) methods reflect both primary and secondary sources of information. The latter (indirect) methods are sensitive only to primary sources. The significance of the two-process theory for the specification of the SDIH and the explanation of other visual phenomena is discussed.

Arterial Blood Pressure and Modernization in Brazil

Abstract: The relationship between individual modernization and elevated arterial blood pressure was examined in a study in urban Brazil. We hypothesized that elevated blood pressure would result from the discrepancy between an individual's style of life and his or her economic resources; specifically, we suggested that when modern life-style acquisition exceeded economic resources, a circumstance referred to as “life-style stress,” blood pressure would be elevated. This factor was related to diastolic, but not systolic, blood pressure, independently of a variety of biologic, dietary, and sociocultural confounding factors. The perceived change associated with life events also predicted diastolic, but not systolic, blood pressure. Other predictors of diastolic blood pressure were calcium intake, fat intake, race, age, and the body mass index. We argue that sociocultural risk factors emerge in the modernization process as a result of social structural imbalances generated by economic development and represent independent risk factors for elevated arterial blood pressure.

Familiar size and the theory of off-sized perceptions

Abstract: The role of familiar size in the visual judgment of size and distance was investigated using reduced conditions of observation and instructions that called for either objective or apparent size and distance judgments. Each observer was presented with one object at one distance (56, 107, or 149 cm). This object, which was of constant physical size, was either a normal-sized playing card or a blank rectangle of the same size as the playing card. Distance responses were verbal and size responses were tactual. For the blank rectangle, reported distance remained constant, whereas judged size decreased as physical distance increased for both objective and apparent instructions. For the playing card, reported distance increased as physical distance increased for both objective and apparent instructions. The judged size for the playing card, however, remained constant with objective instructions but decreased with apparent instructions as the physical distance increased. This pattern of results is consistent with the theory that, to a substantial degree, familiar size contributes to spatial responses by means of a cognitive process based upon familiar objects’ appearing as smaller or larger than normal. Under conditions in which the familiar objects are normal in size (as in the present experiment), this process acts to correct a direct response to distance for any errors that might be present in the perception of distance.

Second order large deviation estimates for ferromagnetic systems in the phase coexistence region

Abstract: We consider thed-dimensional Ising model with ferromagnetic nearest neighbor interaction at inverse temperature β. Let\(M_\Lambda = |\Lambda |^{ - 1} \sum\limits_{i \in \Lambda } {\sigma _i } \) be the magnetization inside ad-dimensional hyper cube Λ, μ+ be the+Gibbs state andm*(β) be the spontaneous magnetization. For β such thatm*(β)>0 we find a sufficient condition (easily verified to hold for large β) for μ+({MΛ∈[a,b]}) to decay exponentially with |Λ|(d−1)/d when −m*

Towards a water balance in the Central Amazonian region

Abstract: structure and topography of the terrain, palms being a prevalent feature in Amazonian forests. Luizfio and Schubart show the importance of litter decomposition and of the soil organisms as decomposers for the recycling of nutrients and thus for the maintenance of the forest, while Rylands gives a detailed account of monkeys as consumers of the living biomass in the forest canopy. Walker, finally, integrates the biology of streams into the general ecological process of forest dynamics. It is hoped that the review conveys one aspect in particular with penetrating clarity: namely, that of the mutual interdependence of all the described processes and patterns from which the multiple dangers to and fragility of this gigantic ecosystem directly follow. The consideration of this balance is indispensible for any land use by man in the Amazon Basin.

Brain endo-oligopeptidase A, a putative enkephalin converting enzyme.

Abstract: Endo-oligopeptidase A, highly purified from the cytosol fraction of bovine brain by immunoaffinity chroma-tography, has been characterized as a thiol endopeptidase. This enzyme, known to hydrolyze the Phe5-Ser6 bond of bradykinin and the Arg8-Arg9 bond of neurotensin, has been shown to produce, by a single cleavage, Leu5-enkephalin or Met5-enkephalin from small enkephalin-containing pep-tides. Enkephalin formation could be inhibited in a concentration-dependent manner by the alternative substrate bradykinin. The optimal substrate size was found to be eight to 13 amino acids, with enkephalin the only product released from precursors in which this sequence is immediately followed by a pair of basic residues. However, the specificity constants (Kcat/Km) obtained for endo-oligopeptidase A hydrolysis of bradykinin, neurotensin, and dynorphin B are of the same order, a result indicating that the substrate amino acid sequence is not the only factor determining the cleavage site of this enzyme.

Autonomic nervous control of the heart rate during isometric exercise in normal man

Abstract: The relative contribution of the efferent components of the autonomic nervous system to the regulation of tachycardia induced by isometric exercise was assessed in 23 normal males. The isometric exercise (handgrip) was performed at the maximum intensity tolerated by the individual over a period of 10 s (maximal voluntary contraction — MVC) and at levels equivalent to 75, 50 and 25% of MVC for 20, 40 and 10 s, respectively. The study was performed both under control conditions and after pharmacological blockade with atropine (12 individuals) or propranolol (11 individuals). Under control conditions, the heart rate (HR) responses to isometric effort were dependent on the intensity and duration of the exercise, showing a tendency towards progressive elevation with the maintenance of muscular contraction at the levels studied. The tachycardia evoked by this effort was of considerable magnitude and of rapid onset, especially at the more intense levels of activity. Parasympathetic blockade markedly decreased tachycardia, which manifested itself during the first 10 s of exercise at all levels of intensity, whereas sympathetic blockade markedly modified the HR response after 10 s of effort at the 75 and 50% MVC levels. A slight depression of the tachycardiac response could be observed already after 10 s of maximum effort after propranolol. The present results suggest that the autonomic regulation of these responses is based on a biphasic mechanism, with the initial phase depending on the rapid withdrawal of the parasympathetic influence, followed by a marked sympathetic contribution to the induction of tachycardia after 10 s of isometric contraction or even a little before at maximum exertion.