Showing papers by "University of São Paulo published in 1975"
TL;DR: The pulmonary veins of albino Wistar rats were studied by means of light and electron microscopy to reveal striking differences in the ultrastructure of media muscle fibers similar to that of rat hearts.
Abstract: The pulmonary veins of albino Wistar rats were studied by means of light and electron microscopy. The media of larger veins consists of cardiac muscle fibers which extend until the vessels attain about 100 mu in diameter. This coat consists of external longitudinal fibers and internal circular fibers. The vasa vasorum are well developed and the capillaries show pseudofenestrations. The numerous adrenergic and cholinergic nerve endings do not form typical motor end-plates as seen in skeletal muscles. The ultrastructure of these media muscle fibers is similar to that of the rat hearts. The smooth muscle layer of larger pulmonary veins is not continuous as it is in smaller veins where it forms cushions. Comparison of albino rats and other rodents reveal striking differences. Action potential shape and propagation velocity (0.5-1.2 m/s) along the myocardial coat of the pulmonary vein were similar to those observed in the left atrium and so was their sensitivity to locally applied acetylcholine. The physiological direction of propagation in rat pulmonary veins is toward the lung. This fingind lends support to the hypothesis of a rhythmic, valve-like action of the striated musculature of the pulmonary venous wall during the systole and a possible role in the capacitance of the pulmonary circulation.
88 citations
TL;DR: In this paper, the authors examined the relationship between thermoluminescence and lattice defect equilibrium in the case of lithium fluoride at and above room temperature, focusing on the relationship of recombination and luminescence, the supralinearity and sensitization of the dosimetry grade of LiF and activation energy parameters.
Abstract: The principal effect of thermal and optical treatments in an ionic solid is to alter the lattice defect equilibrium, including the concentration and arrangement of ion vacancies, impurities, impurity-vacancy associates, and assorted electrons and holes which may be associated with such defects. This paper examines the relationship between these defects and thermoluminescence in the case of lithium fluoride at and above room temperature. The discussion focuses on lattice defect equilibrium, thermoluminescent trapping centers, the relationship between recombination and luminescence, the supralinearity and sensitization of the dosimetry grade of LiF and activation energy parameters.
84 citations
TL;DR: A positive correlation was found between DDT levels and times of exposure, but being in direct or indirect contact with DDT was not always correlated with the degree of contamination.
Abstract: Workers from three insecticide plants in direct contact with 2,2-bis (β-chlorophenyl)-1,1,1,-trichloroethane (DDT) did not differ significantly in the frequencies of cells with chromosomal aberrations when compared with controls from the same plants but not in direct contact with the drug. The same was true when a group of workers from one plant was compared with a control group from the Instituto Butantan, with no history of occupational exposure to DDT. Yet, when the control group from one of the three plants, which showed high DDT plasmic levels, was added to the group in direct contact with the insecticide, the frequency of cells with chromatid aberrations was significantly higher, suggesting that DDT causes chromatid lesions. A positive correlation was found between DDT levels and times of exposure, but being in direct or indirect contact with DDT was not always correlated with the degree of contamination.
66 citations
TL;DR: It was observed at the electron microscope that the architecturally complex terminal tubules, proacinar, acinar and striated duct cells retained mitosis the major ultrastructural features they exhibited in interphase.
Abstract: The development of the submandibular gland of the rat was studied between days 2 and 55 of the postpartum. Besides confirming previous ultrastructural findings wer observed at the electron microscope that the architecturally complex terminal tubules, proacinar, acinar and striated duct cells retained mitosis the major ultrastructural features they exhibited in interphase. The ultrastructure of cells that were in the S period of the proliferative cycle was evaluated in high resolution autoradiographs from rats injected with thymidine-H3. All cell types were thus studied and no obvious cytoarchitectural modifications could be detected in these cells preparing for dividion. We obtained ultrastructural evidence that between days 20 and 30 some terminal tubule cells undergo transformation into acinar cells. The intercalated duct cells showed the highest rate of proliferation and the lowest daily increment in number. This suggests that cells from the intercalated ducts migrate to the neighboring morphological compartments. Quantitative data on the rate of cell proliferation and accumulation in the straited duct indicated that cells from the intercalcated ducts should differentiate into straited duct cells. Differentiation of intercalated duct cells into the terminal tubule cells was observed with the electron microscope.
62 citations
01 Jan 1975
TL;DR: As Sciaenidae family shows to be the most important predominant group each species is studied in detail with reference to its distribution and relative abundance, as well as its spatial and temporal variations according to the abiotic environment.
Abstract: This paper deals with a study on Brazilian south coast continental shelf demersal fish fauna distribution and Sciaenidae ecology, comprising the latitudes between Torres (29o21'S -49o44'W) and Chui (33o41'S - 53o27'W). The data on oceanographic as well as on ichthyological variables were obtained from six cruises planned to cover all seasons during the period from April 1968 to March 1969. The variation of the physical conditions of the bottom water layer is studied covering temperature, salinity, dissolved oxygen and type of bottom. The demersal fish families distribution is presented according to its frequencies of occurrence and its particular abundance. As Sciaenidae family shows to be the most important predominant group each species is studied in detail with reference to its distribution and relative abundance, as well as its spatial and temporal variations according to the abiotic environment. Relationship between Sciaenidae species is also discussed concerning feeding habits and the Cole coefficient of inter-specific association is estimated for pairs of species.
62 citations
TL;DR: The partial purification and some properties of a glycoprotein complex of whole-cell epimastigote forms of T. cruzi are described.
57 citations
TL;DR: The analysis of 30 specimens of Zygodontomys lasiurus disclosed a diploid number of 34 chromosomes, and the male had a pair of dot chromosomes less than the female; such chromosomes might be centric fragments resul...
Abstract: SUMMARYKaryotypes of ten species of Brazilian rodents, collected in the State of Sao Paulo are presented: Akodon (Thaptomys) nigrita nigrita (2 n = 52); Zygodontomys lasiurus (2 n = 34); Thomasomys (Delomys) dorsalis collinus (2 n = 82); Oxymycterus sp1. and Oxymycterus sp2. (2 n = 54); Calomys sp. (2 n = 66); Clyomys laticeps laticeps (2 n = 34); Euryzygomatomys guiara (2 n = 46); Proechimys iheringi iheringi (2 n = 62, 64) and Echimys sp. (2 n = 90).The analysis of 30 specimens of Zygodontomys lasiurus disclosed a diploid number of 34 chromosomes. In three female specimens the length of one X chromosome was half the length of the other, due to a deletion on the long arm. In this case, the probably normal X chromosome presents a subterminal centromere and is morphologically identified.A heteromorphic autosomal pair was found in Oxymycterus sp1. and Oxymycterus sp2.In Proechimys iheringi iheringi the male had a pair of dot chromosomes less than the female; such chromosomes might be centric fragments resul...
56 citations
08 Oct 1975
TL;DR: The hypothetical phytogeny of both tribes based on morphological evidence rombined with geographical patterns, is given and Considerations on the biology and ecology of the Pyrophorini are given.
Abstract: Examination of types and comparative studies of the male and femule genitalia and other morphological characters of all genera of the "Pyrophorini" permitted a reclassification of this tribe. It is divided into two others: Pyrophorini sensu stricto and Heligmini, trib. n. The former, exclusively bioluminescent, includes seventeen genera (Pyrophorus sensu stricto, two genera here revalidated: Phanophorus Solier, 1851 and Hypsiophthalmus hatreille, 1834, and the following new ones: Nyctophyxis, Noxlumenes, Cryptolampros, Sooporanga, Pyroptesis, Hapsodrilus, Ptesimopsia, Pyrearinus, Fulgeochlizus, Opselater, Ignelater, Lygelater, Deilelater and Vesperelater). The latter includes all non luminous genera previously placed within the "Pyrophorini" (except for Hifo Candeze, 1881, Hifoides Schwarz, 1906, Hemirhipus Latreille, 1829, and Chalcolepsis Candeze, 1857) and four new genera originally described in the genus "Pyrophorus" (Agnostelater, Coctilelater, Euplinthus and Arcanelater). Campyloxenus Fairmaire, 1860, is removed from the Pyrophorinae and placed in a new subfamily. The hypothetical phytogeny of both tribes based on morphological evidence rombined with geographical patterns, is given. Considerations on the biology and ecology of the Pyrophorini are given.
48 citations
TL;DR: Parallel image processing shows certain general similarities to retinal processing and shares with optical computing the characteristics of parallelism and possible applications of such processors in image processing, pattern recognition, and artificial intelligence are briefly discussed.
Abstract: Parallel image processing shows certain general similarities to retinal processing and shares with optical computing the characteristics of parallelism. Simulation on digital serial computers (DSC's), although possible in the simpler cases, very soon becomes almost uncontrollable, requiring large memories and very long programming and execution times. Advances in present circuit technology now permit one to construct large arrays of interconnected parallel ogic elements resulting in real-time parallel machines where the action of a statement is simultaneous on all the points of the array. A typical processor of this kind is briefly described and an introduction to its code is given. Examples of symmetrical and directional functions and parallel algorithms are also presented. Possible applications of such processors in image processing, pattern recognition, and artificial intelligence are briefly discussed.
46 citations
TL;DR: It appears that the chemienergized species is indol-3-aldehyde in its triplet state, and the possibility that electronic energy is generated in the indoleacetate/peroxidase/0 2 system, and is responsible for the change is supported by the chemiluminescence observed in the presence of sodium 9,10-dibromoanthracene-2-sulfonate, and of eosin.
TL;DR: In this paper, the reaction of arenetellurenyl halides, generated in situ, with Grignard reagents, with RTeSeR was used to generate symmetric tellurides.
TL;DR: These studies demonstrated satisfactory evolution of the homologous dura mater valves until 35 months after implantation, with no signs of rejection or degeneration of the dURA mater observed.
TL;DR: In this paper, the Coulomb distortion was used to explain the behavior of the nuclear excitation cross-sections produced by electrons and positrons, and it was shown that the value of σ − σ + displays no clear structure corresponding to resonances in the photoabsorption cross-section, except for the presence of quadrupole strength.
TL;DR: A thermodynamic model for the freezing of biological cells has been developed and has been applied to human erythrocytes and the effect of supercooling of the extracellular solution on the kinetics of the cell water loss is analyzed.
Abstract: A thermodynamic model for the freezing of biological cells has been developed and has been applied to human erythrocytes. Analytical expressions describing the dynamics of water loss during the several stages of the freezing process have been derived from a cell modeled as an open system surrounded by a membrane permeable to water only. The permeability of the membrane to water is the most significant cell parameter in this process and in the present model, and is assumed to be a function of the temperature and osmolality of the extracellular solution. The resulting set of differential equations describing the cell freezing process is solved numerically for various cooling rates. For cooling rates less than 3000 K/min, erythrocytes lose 95 percent of their intracellular water before the eutectic temperature is reached. For cooling rates greater than 3000 K/min, the fraction of intracellular water remaining at the eutectic temperature is a strong function of cooling rate. The effect of supercooling of the extracellular solution on the kinetics of the cell water loss is also analyzed. As a consequence of the supercooling, the volume of water present intracellularly at a given temperature is substantially greater than when no supercooling occurs. This condition favors intracellular ice formation and is consistent with experimental observations in this laboratory.
TL;DR: It was concluded that the number of cells in the second prepupal stage is more important than the weight of the prepupa for caste determination, and genes kappa a and kappa b code for an enzyme that directly participates in juvenile hormone production.
Abstract: Cell number and volume of corpora allata was determined for 8 phases of development, the first prepupal stage to adults 30 days old, in the social Apidae Melipona quadrifasciata. In the second prepupal stage a strong correlation was found between cell number and body weight ( r=0.651**), and cell number and corpora allata volume in prepupal stage (r=0.535*), which indicates that juvenile hormone has a definite role in caste determination in Melipona. The distribution of the volume of corpus allatum suggest a 3:1 segregation between bees with high volume of corpora allata against low and medium volume. This implies that genes xa and xb code for an enzyme that directly participates in juvenile hormone production. It was also concluded that the number of cells in the second prepupal stage is more important than the weight of the prepupa for caste determination. A scheme summarizing the genic control of sex and caste determination in Melipona bees in the prepupal phase is given.
TL;DR: The reaction of 2,4-dinitrofluorobenzene with phenoxide and thiophenoxide ion in water is strongly catalyzed by micelles of cetyltrimethylammonium bromide (CTABr) by factors of 230 and 1100 respectively as mentioned in this paper.
TL;DR: The wood of the vine Derris rariflora (Leguminosae-Lotoideae) contains 3,5-dimethoxy-4-prenylstilbene, (2S)-5,7-dihydroxy-6prenylflavanone and 5,hydroxy-7-methoxy 6prenyi lavanone as discussed by the authors.
TL;DR: In this paper, a mechanism based on formation of an intermediate or activated complex of the type [Fe(CN)5O2Feaq]− was proposed, based on which the reaction rate was observed with k3 = 5.6 ± 0.1 × 106M−2 s−1 at 25°C, μ = 0.10M lithium perchlorate, pH 4.50.
TL;DR: In this paper, the spectral properties of iron diimine complexes were investigated, including the metal to ligand electron transfer (MLET) bands in the visible region and the lLET band in the UV region.
TL;DR: Product inhibition studies and transphosphorylation to methanol using two different substrates indicate that acid phosphatase from bovine brain forms a phosphoryl enzyme and that the phosphorylation step can not be rate limiting.
TL;DR: 1,2-Dioxetanes, widely believed to be intermediates in bioluminescence and in dioxygenases systems, are likely to be formed also in several other systems, and these systems may release a large amount of energy which might perform normal and pathological functions.
TL;DR: The H + electrometric and Cl − complexometric titrations of crotamine hydrochloride showed that about 13 moles of HCl are bound per 4760 g of the free base, which corresponds to a minimum molecular weight of 4760.
TL;DR: Abstract (3 R )-Claussequinone (7-hydroxy-4′-methoxyisoflavanquinone) is the principal constituent of Cyclolobium clausseni Benth.
TL;DR: In the DNA puff regions the rate of DNA chain elongation is higher when amplification occurs than during a normal replication cycle, and it seems that the higher rate during amplification is dependent upon de novo RNA synthesis.
Abstract: Injection of β-ecdysone into mid fourth instar larvae of Rhynchosciara americana induced within 23–28 hours after injection a rise in the percentage of 3H-thymidine (3H-TdR) incorporating nuclei in salivary gland region S1 from about 10–20% in the controls to 80–90% in the injected larvae. The 3H-TdR incorporating nuclei displayed a weak continuous labeling pattern or a band-labeling pattern with grains over the vast majority of the bands. The majority of nuclei with a band labeling pattern displayed DNA amplification at the DNA-puff regions. — Injection of actinomycin D at different times after ecdysone injection abolished the higher incorporation rate at the amplifying regions within 15 hours after the injection. However, the percentage of nuclei incorporating 3H-TdR and the frequency of the two labeling patterns remained essentially the same when RNA synthesis was inhibited. Only the over-all rate of 3H-TdR incorporation seemed to be reduced. — These data suggest that in the DNA puff regions the rate of DNA chain elongation is higher when amplification occurs than during a normal replication cycle. It, further, seems that the higher rate during amplification is dependent upon de novo RNA synthesis.
TL;DR: Transection of the cervical spine regularly produces violent generalized convulsions in the rat, mouse, and rabbit, but not in the guinea pig, and these agonal seizures are completely suppressed by chronic treatment with high doses or reserpine and by phenoxybenzamine.
TL;DR: Concluiu-se that esta especie e dotada de elevada capacidade de disseminacao, em concordância com sua apreciavel valencia ecologica, está disponible na colonias desenvolvidas espontaneamente em ecotopos artificiais.
Abstract: Nas colonias desenvolvidas espontaneamente em ecotopos artificiais, representados por galinheiros experimentais, procurou-se observar a permanencia e a mobilidade de Triatoma sordida. Para tanto, procedeu-se a marcacao individual de adultos e ninfas de 4.° e 5.° estadios, bem como a instalacao de abrigos ao redor daqueles biotopos. Os dados obtidos permitiram observar a curta permanencia dos primeiros na colonia, nao ultrapassando o periodo de dois meses para a maioria dessas formas. A mobilidade evidenciou-se pela presenca de ovos e ninfas de 1.° estadio, nos esconderijos instalados, e as evidencias sugeriram ser devidas a passagem dos adultos por esses ecotopos. Concluiu-se que esta especie e dotada de elevada capacidade de disseminacao, em concordância com sua apreciavel valencia ecologica.