Showing papers by "University of São Paulo published in 1984"
TL;DR: Both the human and the mouse c-myc genes stimulate clonal growth of 3T3 cells in PDGF-free medium suggesting new strategies for analysis of oncogenes which do not function in focus formation assays.
Abstract: In BALB/c-3T3 cells, expression of the c-myc gene is stimulated by platelet-derived growth factor (PDGF). Using mouse mammary tumour virus promoter: c-myc recombinant plasmids, 3T3 sublines were constructed in which hydrocortisone was the primary determinant of myc mRNA content. The c-myc gene product is an intracellular mediator of the growth response to PDGF though probably not the only one. Both the human and the mouse c-myc genes stimulate clonal growth of 3T3 cells in PDGF-free medium suggesting new strategies for analysis of oncogenes which do not function in focus formation assays.
506 citations
TL;DR: Reduced precipitation in the Amazon could increase the tendency toward continentality and adversely affect climate and the present agriculture in south-central Brazil.
Abstract: Despite the very active deforestation of the last decade, the Amazon Basin is still primarily covered with trees and is a system in equilibrium. The Andes form a barrier at the western end of the basin and, coupled with the prevailing easterly winds, ensure an almost unique precipitation and water-recycling regime. On average 50 percent of the precipitation is recycled, and in some areas even more. The soils are poor. Most of the nitrogen and phosphorus is found in the soil, and the remaining nutrient elements are found in the standing biomass. There is some nutrient recycling and little loss from the intact ecosystem, and the small input of nutrients from precipitation maintains a small positive nutrient balance. Continued large-scale deforestation is likely to lead to increased erosion and water runoff with initial flooding in the lower Amazon, together with reduced evapotranspiration and ultimately reduced precipitation. Reduced precipitation in the Amazon could increase the tendency toward continentality and adversely affect climate and the present agriculture in south-central Brazil.
485 citations
TL;DR: The chelator therefore removes iron from the chromatin, and although the Fe-EDTA complex formed is capable of reacting with H2O2, the OH radical generated under these conditions is not close enough to hit DNA.
340 citations
TL;DR: In this paper, Gatheral generalized the well-known exponentiation properties of soft photons in QED to the case of soft gluons in QCD in the eikonal approximation.
331 citations
TL;DR: In this paper, a new approach to metastability for stochastic dynamics is proposed, where the authors study the statistics of each path, performing time averages along the evolution, and show that the process of these time averages converges, under a suitable rescaling, to a measure valued Markov jump process.
Abstract: In this paper a new approach to metastability for stochastic dynamics is proposed. The basic idea is to study the statistics of each path, performing time averages along the evolution. Metastability would be characterized by the fact that the process of these time averages converges, under a suitable rescaling, to a measure valued Markov jump process. Here this convergence is shown for the Curie-Weiss mean field dynamics and also for a model with spatial structure: Harris contact process.
242 citations
TL;DR: The rate of loss of reproductive capacity produced by hydrogen peroxide was shown to be 6-times faster for human fibroblasts than for Chinese hamster fibro Blasts, and it is proposed that this difference may lie in the amount of chromatin-bound iron and the level of superoxide ion in these cells.
115 citations
TL;DR: In this article, the authors deal with the correlation between the geotectonic features of the basement and the internal structure, shape, geologic evolution, etc of the major sedimentary basins of the South American platform.
112 citations
TL;DR: It is suggested that the structure of a roost's community is primarily determined by the location: the more isolated a cave, the greater and more diversified tends to be its community, regardless of the caveis morphometric characteristies («opportunistic occupation»).
Abstract: The upper valley of the Rio Ribeira, a carbonatic rock region in the south of the state of Sao Paulo, Brazil, has a great number of caves; the bat community of the area is the subject of the present study. Between October 1978 and October 1980 specimens of five families and 23 species were captured. The species showed an irregular distribution among 32 of 39 caves visited. The community is very diversified, consisting of a specially abundant species (Desmodus rotundus), some very common species (Carollia perspicillata, Artibeus lituratus and Anoura caudifer), and several common and rare species. It differs from other neotropical communities studied in the relatively high frequence of A. caudifer, which probably takes over the ecological role of Glossophaga soricina, and in the great diversity of medium to large sized Phyllostominae. The great diversity and the high relative abundance of some species is probably related to the availability of food afforded by farms and domestic stock N important for the herbivorous and hematophagous species N and to the high number of caves N important mainly for the Phyllostominae and probably for D. rotundus. It is suggested that the structure of a roost's community is primarily determined by the location: the more isolated a cave, the greater and more diversified tends to be its community, regardless of the caveis morphometric characteristies («opportunistic occupation»). Only in densely grouped caves factors such as size would tend to be of some importance. Due to the great number of roosts and the lotv sociability of the bats, the Upper Ribeira populations tend to be distributed all over the available caves, that have small populations (with exception of some relatively isolated ones) varying in density through the year. The occurrence of certain species in individual caves seems to be affected by presence of others in the same roost: A. lituratus, Diphylla ecaudata and Chrotopterus auritus tend to occupy the same caves as D. rotundus, whereas Puripterus horrens and A. caudifer avoid them. Common species showed a «sunset-related» timing of flight activity. The emergence of the majority of the populations begins at dusk, but the activity peak at cave entrance varies in timing and duration. The strictly insectivorous species (Peropterix macrotis, Myotis nigricans and P. horrens and also A. caudifer leave the roost earlier, showing an emergence peak during the crepuscle; for the others, the peak occurs after darkening. A few species, such as D. rotundus and Lonchorhina aurita, emerge only after total darkness. The use of temporary, nocturnal roosts seems to be frequent in the Upper Ribeira, occurring during or after foraging activities; individuals of A. lituratus can use caves as ingesting places. C. perspicillata finishes its feeding activities earlier than the other common species, which indicates a high foraging efficiency. With few exceptions, bats of the Upper Ribeira do not carry their young during foraging. The supply of food for the hematophagous species is represented by small and medium sized domestic animals (poultry and pigs); wild animals may also be significant as prey.
93 citations
TL;DR: As an initial step in investigating the role of steroid hormones in lymphangiomyomatosis, the cytosolic receptors for steroid hormones were determined by a dextran charcoal method and were significant because specimens of normal lung display no receptor at all.
92 citations
TL;DR: Investigation of the binding of a local anesthetic, tetracaine, to egg phosphatidylcholine membranes indicates that the drug apparent pK decreases in the presence of membranes, the decrease being a function of membrane concentration.
85 citations
TL;DR: In this article, the Hori auxiliary system for the motion of two planets, whose motions around the Sun have commensurable periods in the ratio 2 : 1, is completely integrable and, an intermediate orbit that includes the effects of the resonance is obtained.
Abstract: It is shown that the Hori auxiliary system for the motion of two planets, whose motions around the Sun have commensurable periods in the ratio 2 : 1, is completely integrable and, an intermediate orbit that includes the effects of the resonance is obtained. The difficulties of classifying some solutions as librations or circulations are discussed.
TL;DR: The results indicate that transcatheter embolization should be performed in patients with renal trauma and uncontrollable hematuria before any surgical attempt is made.
TL;DR: It is suggested that vasoactive substances, endowed with permeability‐increasing properties, evoke relaxation of microvessels through an insulin‐dependent action on endothelial cells, unrelated to the release of arachidonic acid metabolites, which would provide the basis for vasodilatation.
Abstract: 1
The response to vasoactive agents of microvessels of the rat was tested in vivo by direct microscopic observation of the exteriorized mesentery and assessment of cutaneous vascular permeability changes with Evans blue.
2
The constrictor response to a standard amount of noradrenaline in mesenteric microvessels was fully antagonized by acetylcholine in normal, diabetic, adrenalectomized and diabetic-adrenalectomized rats. In contrast, the minimum doses of histamine or bradykinin, effective in normal or adrenalectomized animals, had to be increased about 20 fold to be active in diabetic or diabetic-adrenalectomized animals.
3
Topical application of insulin to mesenteric microvessels of diabetic animals, in amounts not causing any increase in serum insulin levels, improved or restored the capacity of the animals to respond to histamine or bradykinin, acting as antagonists of the vasoconstrictor response to noradrenaline. Topical insulin, however, was ineffective in normal animals given 2-deoxyglucose, the acute effects of which result from cellular glucopaenia unrelated to insulin deficiency.
4
Vascular permeability responses to intracutaneous histamine or bradykinin were decreased in animals pretreated with 2-deoxyglucose as much as in diabetic animals.
5
Pretreatment of normal animals with indomethacin produced no effect on the responses of these animals to histamine or bradykinin, tested as antagonists of noradrenaline on mesenteric microvessels, or as vascular permeability-increasing factors in the skin.
6
Pretreatment of normal animals with chloroquine, mepacrine or dexamethasone had no effect on the reactivity of mesenteric microvessels to histamine and bradykinin, acting as antagonists to noradrenaline.
7
It is suggested that vasoactive substances, endowed with permeability-increasing properties, evoke relaxation of microvessels through an insulin-dependent action on endothelial cells, unrelated to the release of arachidonic acid metabolites. This action would lead to increased vascular permeability, with opening of interendothelial junctions, and temporary changes in composition of extravascular fluid, which in turn, would provide the basis for vasodilatation. Diabetes mellitus apparently impairs such responses as a result of the accompanying cellular glucopaenia. Adrenal corticosteroids are not involved in the impaired responses.
TL;DR: The results suggest that the anterior and middle region of the midgut absorbs water, whereas the posterior region secretes it and results in a countercurrent flux of fluid, which is responsible for the enzyme recovery from undigested food before it is expelled.
Abstract: Columnar cells of the larval midgut of the cassava hornworm, Erinnyis ello, display microvilli with vesicles pinching off from their tips (anterior and middle midgut) or with a large number of double membrane spheres budding along their length (posterior midgut). Basal infoldings in columnar cells occur in a parallel array with many openings to the underlying space (posterior midgut) or are less organized with few openings (anterior and middle midgut). Goblet cells have a cavity, which is formed by invagination of the apical membrane and which occupies most of the cell (anterior and middle midgut) or only its upper part (posterior midgut). The infolded apical membrane shows modified microvilli, which sometimes (posterior midgut) or always (anterior and middle midgut) contain mitochondria. The cytoplasmic side of the membrane of the microvilli that contain mitochondria are studded with small particles. The results suggest that the anterior and middle region of the midgut absorbs water, whereas the posterior region secretes it. This results in a countercurrent flux of fluid, which is responsible for the enzyme recovery from undigested food before it is expelled. Intermediary and final digestion of food probably occur in the columnar cells under the action of plasma membrane-bound and glycocalix-associated enzymes.
TL;DR: Sommerfeld's edge-wave formulation of diffraction is employed to show how angular distributions for heavy-ion elastic scattering can profitably be interpreted as 2-slit diffraction patterns modified by refraction as discussed by the authors.
TL;DR: A putative melanin-concentrating hormone was synthesized that has about one six-hundredth of the activity of alpha-melanocyte-stimulating hormone on frog and lizard melanocytes and is a full agonist.
Abstract: A putative melanin-concentrating hormone was synthesized. This peptide, H-Asp-Thr-Met-Arg-Cys-Met-Val-Gly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Glu-Val-OH , stimulates melanin granule aggregation within teleost melanocytes at nanomolar concentrations as does the natural purified teleost pituitary preparation. In addition, this peptide stimulates melanin granule dispersion within melanocytes of frogs and lizards. The peptide has about one six-hundredth of the activity of alpha-melanocyte-stimulating hormone on frog and lizard melanocytes and is a full agonist.
TL;DR: Surprisingly, the melanotropins were more active in the in vivo assay than in theIn vitro bioassay, and it is unclear why the hormone was more active as measured in vivo and why the darkening response in vivo persisted so long.
TL;DR: The zooplankton of ten reservoirs of Sao Paulo State was analyzed as part of a larger project, "Typology of Reservoirs of Brazil State".
Abstract: The zooplankton of ten reservoirs of Sao Paulo State was analyzed as part of a larger project, ‘Typology of Reservoirs of Sao Paulo State’.
TL;DR: Data obtained with both rabbit and frog muscle indicate that toxin γ is specific for Na+ channels in surface membranes, and competition experiments have confirmed that Tityus γ toxin binds to a new toxin receptor site on the Na+ channel structure.
Abstract: Toxin γ from the venom ofTityus serrulatus scorpion produces a partial block of the surface Na+ channel in frog muscle. This block occurs with no change in the voltage-dependence or in the kinetics of the remaining surface Na+ current. The partial blockade of Na+ channel activity occurs with no change in tubular Na+ currents nor in twitch tension. The maximum effect of the toxin is attained at concentrations as low as 3×10−10 M. Hyperpolarization to potentials more negative than the resting potential (E=−90 mV) reduces or abolishes the effect of the toxin.
TL;DR: C-banding analysis of the mitotic chromosomes revealed constitutive heterochromatin in the centromeric regions of all acrocentrics, however, small metacentrics were C-band negative.
Abstract: Chromosomes of Eigenmannia sp. (7 males and 15 females) collected from the Tiete River in Botucatu (SP, Brazil) were examined from gill, kidney and testicular cells. The diploid chromosome number in males was 2n=31 and in females, 2n=32. In both sexes the number of chromosomal arms was 40. The difference in diploid number was due to the fusion of two acrocentrics. Mitotic and meiotic studies suggested that one of the fused acrocentrics was the Y chromosome. The sex-determining mechanism in Eigenmannia sp. could therefore be XX, AA in the female and X, \-YA A in the males. One of the males presented 2n=30 chromosomes due to the occurrence of another fusion of acrocentrics. C-banding analysis of the mitotic chromosomes revealed constitutive heterochromatin in the centromeric regions of all acrocentrics. However, small metacentrics were C-band negative. The YA chromosome is C-band negative except for a small amount of heterochromatin in the centromeric region. The nucleolar organizer region as identified by Ag-staining is present in the interstitial region of chromosome pair No. 10.
TL;DR: Etude de la reaction d'echange entre des anions monovalents and divalents dans des solutions micellaires d'un agent de surface cationique (palmityltrimethylammonium) a l'aide de 2 methodes differentes: l'extinction de la fluorescence des echantillons solubilises dans les micelles and l'ultrafiltration.
Abstract: Etude de la reaction d'echange entre des anions monovalents et divalents dans des solutions micellaires d'un agent de surface cationique (palmityltrimethylammonium) a l'aide de 2 methodes differentes: l'extinction de la fluorescence des echantillons solubilises dans les micelles et l'ultrafiltration
TL;DR: Minor tranquillizers attenuate behavioural responses induced by aversive brain stimulation in several experimental conditions and are likely to mediate, at least in part, their clinical anti-anxiety effect.
TL;DR: The low regeneration capac ity of buds presented by the calli seems to be the result of an incomplete dedifferentiation of their cells, which seems to keep the callus in a “root state”.
Abstract: The effects of an auxin (NAA) and a cyto kinin (BA), as well as those of peptone, thiamin and coconut water (CW) on callus and protocorm-like body (PLB) induction from root tips of Oncidium varicosum grown in vitro were studied. Relatively high concentrations of NAA favoured callus induction. PLBs were obtained from callus culture either in medium with 15% CW+1.25 mg/1 NAA or in the presence of CW alone. The low regeneration capac ity of buds presented by the calli seems to be the result of an incomplete dedifferentiation of their cells. This seems to keep the callus in a “root state”. The apparent presence of high cytokinin levels either in the explant or in the callus may be related to these processes.
TL;DR: Methylnalorphinium, a mixed opiate agonist-antagonist devoid of central effects, might be considered the prototype of an ideal peripheral analgesic since it was orally active, did not affect intestinal transit and did not cause analgesic tolerance.
TL;DR: The results support the proposal that intermediate and final digestion in Erinnyis ello occur under the action of glycocalyx-associated hydrolases and of plasma membrane-bound enzymes (aminopeptidase, and perhaps also amylase and trypsin).
TL;DR: The radioactive element distribution in the Archean granulite facies rocks of Jequie, Brazil, has been determined as discussed by the authors, showing that the relatively high concentrations of the radioactive and other elements in Jeiquie granulites probably represents the relict primary geochemical character, little modified during metamorphism.
Abstract: The radioactive element distribution in the Archean granulite facies rocks of Jequie, Brazil, has been determined. The K/Rb ratios show a large spread with majority of the values falling within the normal field (K/Rb<300). The Th/U ratios fall into two groups, one group with values in the range of 1.7 to 2.6, whereas the other group show Th/U values greater than 7 (7 to 25). These distributions can be explained on the basis of the presence of accessory minerals apatite and zircon. The relatively high concentrations of the radioactive and other elements in Jequie granulites probably represents the relict primary geochemical character, little modified during metamorphism. The radiogenic heat production data for the area are calculated and using the measured regional heat flow value from nearby area an estimate of the relative thickness of the continental lithosphere is made using the model developed by Oxburgh (1981).
TL;DR: The susceptibility of Ae.
Abstract: Rocio encephalitis is an epidemic flaviviral infection of man first described in Sao Paulo, Brazil, in 1975. Rocio virus has been isolated from arthropods collected in nature only once, and the vector relationships of the virus in Brazil are essentially unknown. We report here on the first vector competence studies undertaken with mosquito strains from the epidemic zone. Aedes scapularis F1 progeny from females collected during May, November, December, January, and February at Pariquera-Acu, Brazil, were susceptible to per os infection with Rocio virus. The ID50 [ca. 103.5 Vero cell plaque-forming units (PFU)] is well within the range of a competent vector. Infection and transmission rates of 100% were achieved when Ae. scapularis fed on a chick circulating 107.5 PFU/ml of virus; however, infection rates generally were lower. The susceptibility of Ae. scapularis to oral infection with Rocio virus, its ability to transmit virus experimentally, and its abundance and close association with man in the epidemic zone make this species a prime suspect as a vector during the 1975 and 1976 epidemics in Sao Paulo State.
TL;DR: Nymphs of the three perlid genera known from southeastern Brazil, Anacroneuria, Kempnyia and Macrogynoplax, are distinguished morphogically and a key is provided for their determination.
Abstract: Nymphs of the three perlid genera known from southeastern Brazil, Anacroneuria, Kempnyia and Macrogynoplax, are distinguished morphogically and a key is provided for their determination.
TL;DR: Patients with suspected rabies showed no clinically important side effects of systemically administered and locally injected leukocyte interferon, but in the patients treated at the highest dosage, a diminished and delayed antirabies neutralizing antibody titer was observed.
Abstract: Body fluids and brain tissue from rabid human patients have demonstrated only low titers of interferon. Therefore, pharmacokinetic studies of systemically administered and locally injected leukocyte interferon were performed in 2 North American patients with suspected rabies who showed no clinically important side effects of this therapy. Similar therapy was given to 5 patients with symptomatic rabies in Europe and America. Although no prolongation of the clinical course was seen in 3 patients given high-dose intraventricular and systemic therapy, treatment was not initiated until between 8 and 14 days after symptoms were seen. The intraventricular dosage regimen produced cerebrospinal fluid levels that appeared to fall progressively over the 24 hours after injection and demonstrated good but somewhat delayed distribution into the lumbar sac. Titers produced by this therapy were 30- to 10,000-fold higher than those normally observed in this infection, however. In the patients treated at the highest dosage, a diminished and delayed antirabies neutralizing antibody titer was observed, probably a result of the administration of the exogenous interferon.
15 Dec 1984-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the determination of errors on results of experiments with small numbers of events is discussed, and the procedure is checked using Monte Carlo simulation using the Bayesian statistical approach.
Abstract: The determination of errors on results of experiments with small numbers of events is discussed. Tables of confidence intervals for the Poisson distribution and for the ratio and the difference between small numbers of events are presented. The procedure is checked using Monte Carlo simulation. We re-evaluate the errors on some experimental results already published. The Bayesian statistical approach is adopted.