133 resultados para V-T EQUATION


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Total urinary neutral 17-steroids were determined in normal and in castrated horses. One liter of a 15-26 hours urine collection was hydrolysed by refluxing with 10% HC1 (v/v) for ten minutes and extracted with peroxyde-free ethyl ether. The extract was purified by washing with saturated NaHCO³ and KOH solutions. One half of the crude neutral fraction was fractionated with Girard's "T" reagent . The Zimmermann reaction was performed both in the ketonic and in the crude neutral extracts, using alcoholic 2.5N KOH and a 60 minutes period for the colour development in the dark. Optical density measuments were made in a grating Coleman Universal Spectrophotometer at 420 mµ and 520mµ; for the crude neutral fraction a colour correction equation was applied. The aliquot fraction used for colorimety was adjusted for keeping optical density measurements within the range 0.2 to 0.7. Androsterone (mp. 184-184.5°C) with an absorption maximum at 290.5 mµ (Beckman Model DU Spectrophotometer) was used as a reference standard. Table I, ilustrates the results obtained. At the 0.05 probability level there is a significant difference among castrated and normal group means (Fischer's "t" test.) when were used the data obtained from the ketonic fractions; in spite of the use of a colour correction applied for inespecific chromogens, the same results could not be obtained with the crude neutral fractions, Since Girard's reagent fractionation is generaly accepted as the best method for correcting the inespecific chromogen interference in the determination of the 17-ketosteroids by the Zimmermann reaction, we emphasize the value of the results obtained with the ketonic fractions. From these results it appears, as occurs in others mammals, that castrated horses show a lower level of urinary 17-ketosteroids excretion than the normal horses. The significance of the horse testis contribution for the neutral urinary steroid metabolites is discussed. Since horse urine has a low androgenic activity, the fractionation of the neutral 17-ketosteroids must be studied more accurately.

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Neste trabalho, faz-se o estudo das estruturas anatômica e histológica do testículo de Triatoma infestans. Da espermiogênese, descrevem-se apenas as fases que medeiam entre a formação dos espermiogônios e a dos espermídeos (espermiocitogênese). A espermiohistogênese bem como as anatomias do vas deferens e das glândulas anexas serão tratados na segunda parte dêste trabalho, já em preparo. O testículo de Triatoma infestans possui 7 folículos dos quais cada um se abre num vas efferens próprio, curto, desembocando êstes num único vas deferens geral. Na zona de transição entre vas efferens e vas deferens, encontra-se sempre um conjunto de massas tissulares que se estão necrosando em virtude da decomposição das paredes dos cistos. Em conseqüência, os feixes de espérmios são libertados e passam através do vas efferens para o vas deferens. As substâncias líquidas que então se formam, resultado da necrose, são reabsorvidas pelo epitélio do vas efferens, entrando novamente em circulação na hemolinfa; o epitélio possui um rabdório muito longo. A parte superior do conteúdo de cada folículo dispõe-se ao redor de grande célula apical cuja função principal deve ser a de uma atividade reguladora que está relacionada com a diferenciação das células do conjunto germinativo em espermiogônios primários e em núcleos das paredes dos cistos. Nos espermiogônios, serão verificadas 8 divisões de multiplicação, o que vai dar a formação de 256 espermiócitos, número êsse que depois das duas divisões de maturação, que se seguem, originará 1 024 espermídeos. Em seguida, são descritos os fenômenos que ocorrem durante a prófase e as duas divisões de maturação. Temos que admitir a existência de uma parasíndese. Pela formação das tétrades, pode-se concluir que a primeira divisão é reducional e a segunda equacional, existindo, pois, uma pré-redução. Triatoma infestans possui 22 cromosomas no espermiogônio, dos quais 2 são heterocromosomas, sendo X, o maior e Y, o menor, pois, por observações comparadas de oogônios, verificou-se que o grande está ausente, enquanto o pequeno existe em número duplo. Os autosomas da guarnição equatorial, reduzidos pela primeira e segunda divisões de maturação, podem ser distribuídos, quanto ao seu tamanho, em três grupos: 3 grandes (A,B e C), 2 médios (D e E e 5 pequenos (F, G, H, I e K). A, B e C, bem como os heterocromosomas, são heteropicnóticos, formando, tanto nos espermiogônios como nos espermiócitos, depois da sinapsis, um corpo de 8 valores, respectivamente de 5 valores, corpos êsses que permanecem fortemente condensados, mesmo quando os outros cromosomas se individualizam ou quando formam os cromosomas difusos. O estádio dos cromosomas é analisado e considerado como uma fase ativa durante o tempo do crescimento intensivo dos espermiócitos.

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In this paper of the catalogue of south brazilian arboreal pollen grains, the autor deals with the Papilionatae. The Mimosoideae and Caesalpinioideae are yet in preparation, so that a discussion of the three subfamilies (or families) is not possible. In relation with the systematical subdivision of the Papilionatae, we found a large correspondence with the morphology of the present pollen grains. The group of Phaseoleae contains the genera Mucuna, Erythrina and Dioclea; the grains of the studied species are very different one from another; the first of the genera possesses very volumous grains, with three colpori and a reticulated superficies; the second has three-porated pollen grains with a large reticulated superficies, and the third, Dioclea, is yet different; it possesses oblated grains, each three-colporated, with a thick sexine and a psilated superficies. So, we can say, that Phaseoleae is a erypalynous group. Dalbergieae, with the genera: Andira, Dalbergia, Lonchocarpus, Machaerium, Platymiscium and Pterocarpus (and Dahlstedtia, the only exception), has very uniform pollen grains, and may be considered stenopalynous. It is not possible to include the genus Dahlstedtia into this group. A little exception is represented by Pterocarpus violaceus, because of the reticulated sexine of its grains, while the others, also three-colporated, possess a tectate-reticulated sexine. The genera Myrocarpus and Ormosia, from Sophoreae, are very more similar to the Dalbergieae as to any other genus of the Phaseoleae.

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Microtriatoma pratai sp. n. de Hemíptera, Reduviidae, Triatominae, Bolboderini, é descrita no presente trabalho com base em um exemplar coletado em domicílio da cidade do Salvador, Estado da Bahia, Brasil. A espécie se distingue facilmente das outras conhecidas do gênero, principalmente por apresentar asas sem manchas e conexivo com largas manchas claras e escuras alternadas.

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The morphological sequence of Trypanosoma rangeli development in the alimentary canal of Rhodnius prolixus, is described, with observation made in dissected guts from 6 hours to 45 days post-infection. No metacyclic-forms are produced in the digestive tract at any time, and transmission by the contaminative route must be considered atypical. Amastigotes appear to be an essential stage in the development of T. rangeli in the gut of R. prolixus. The epidemiological importance of the developmental pattern of T. rangeli in the vector´s gut is discussed, and its usefulness for aging infection is considered.

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Trypanosoma cruzi infected Rhodnius robustus and/or Rhodnius pictipes were commonly found, in large numbers, in the Brazilian Amazonian palms Maximiliana regia ("inajá"), Acrocomia sclerocarpa ("mucajá") and Orbignya speciosa ("babaçu"). The common opossum, Didelphis marsupialis, was the animal most frequently associated with triatomine infested palms. R. pictipes, frequently light-attracted into houses from palm trees, was the probable source of an acute case of Chagas' disease in the vicinity of Belém. It is considered that triatomine infested palms are likely to cause some cases of acute Chagas' disease in the States of Amazonas and Rondônia. Possible control methods are suggested.

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Apresentamos os resultados de observações sobre os criadouros dos mosquitos, que realizamos numa fazenda - Granjas Calábria, da Baixada de Jacarepaguá, Rio de Janeiro, no período de agosto de 1981 a julho de 1983. A maioria das espécies locais preferiu coleções líquidas no solo, particularmente as de caráter natural, não deixando, entretanto, de procurar aquelas propiciadas pelas atividades humanas. Os criadouros transitórios foram mais freqüentados por Culex saltanensis e pelas espécies da tribo Aedini, como Aedes scapularis, Aedes taeniorhynchus, Psorophora ciliata e Psorophora confinnis, enquanto os de caráter permanente foram mananciais de formas imaturas de Mansonia titillans, Culex amazonensis, Culex chidesteri, Culex bidens, Culex declarator, Culex nigripalpus e Culex plectoporpe. Algumas espécies foram coletadas em recipientes naturais: Culex ocellatus, os Culex (Microculex), Phoniomyia davisi, Phoniomyia deanei e Wyeomyia forcipenis, em bromélias; Aedes terrens, Culex gairus e Culex imitador, em buraco em árvore; e Wyeomyia leucostigma, em axilas submersas das folhas de taboas (Thypha dominguensis). Culex gairus foi encontrado pela primeira vez criando em recipientes artificiais, locais também preferidos por Culex corniger, Culex quinquefasciatus e Limatus durhami.

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Realizamos capturas simultâneas de flebótomos, no Parque Nacional da Serra dos Orgãos, Estado do Rio de Janeiro, utilizando três iscas: homem, gambá e galo. Em 298h capturamos 1.155 fêmeas de seis espécies do gênero Lutzomya. L. ayrozai e L. hirsuta foram as espécies mais numerosas; ambas sugaram somente próximo ao solo, sendo decididamente antropofílicas e mais ativas entre 17 e 24h. L. fischeri foi a espécie mais freqüente na copa e a que demonstrou maior ecletismo quanto ao hospedeiro, hora e local; na copa sugou mais o galo, especialmente entre 0 e 5h e, no solo, picou com maior intensidade o homem, principalmente entre 20 e 24h.

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Les auteurs décrivent le mâle et la femelle d'une nouvelle espèce de phlébotome Lutzomyia brisolai n.sp., anthropophile, rencontrée dans plusieurs stations du piémont andin. Cette espèce, difficile à classer, présente des caractères l'apparentant à L. oliveirai et L. minasensis mais aussi aux espèces du sous-genre Nyssomyia.

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The assessment of yellow fever vaccine thermostability both in lyophilized form and after reconstitution were analyzed. Two commercial yellow fever vaccines were assayed for their thermal stability. Vaccines were exposed to test temperatures in the range of 8 (graus) C to 45 (graus) C. Residual infectivity was measured by a plaque assay using Vero cells. The titre values were used in an accelerated degradation test that follows the Arrhenius equation and the minimum immunizing dose was assumed to be 10 (ao cubo) particles forming unit (pfu)/dose. Some of the most relevant results include that (i) regular culture medium show the same degradation pattern of a reconstituted 17D-204 vaccine; (ii) reconstituted YF-17D-204 showed a predictable half life of more than six days if kept at 0 (graus) C; (iii) there are differences in thermostability between different products that are probably due to both presence of stabilizers in the preparation and the modernization in the vaccine production; (iv) it is important to establish a proper correlation between the mouse infectivity test and the plaque assay since the last appears to be more simple, economical, and practical for small laboratories to assess the potency of the vaccine, and (v) the accelerated degradation test appears to be the best procedure to quantify the thermostability of biological products.

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New species of several speciemens of several specimens from Rio de Janeiro county, caught on the Spinosa platensis microalgae breeding in the concret thanks is described.

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In population surveys in wich the Schistosoma mansoni intensity of infection is low, or in localities where the schistosomiasis control program had success the parasitologic methods lack in sensitivity. Despite of some limitations the immunological methods are useful to provide valuable information in such field conditions. Thus, the prevalaence of schistosomiasis in untreated population can be determined by the detection of IgG or IgM antibodies, as well as the incidence by the IgA antibodies , employing mainly immunofluorescence (IF) and immunoenzymatic (ELISA), and in some extent hemagglutination (HA) or even skin test. The true prevalence and incidence of schistosomiasis can be estimated using a probabilistic model equation, since knowing before-hand the sensitivity and specificity of emploved test. The sensitivity and the specificity of serologic test become higher in low aged group, under 14. The geometric mean IF titers also gives a positive correlation with the intensity of infection. Presently there are need of serologic tests wich are economic and pratical in soroepidemiologic inquires, requiring no specialized personnel to collect population blood or serum and also easily interpret the test results. The reagents for such tests are desired to be stable and reproducible. Moreover, it is expected that the tests can distinguish an ative infection.

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This paper discusses current evidence for the relationship between polyclonal lymphocyte activation, specific immunossupression with decreased resistance, and autoimmune pathology, that are all often found associated with infections by a variety of virus, bacteria and parasites . The central question of class determination of immune effector activities is considered in the context of the cellular targets for nonspecific mitogenic activities associated with infection. A model is presented to integrate these findings: mitogenens produced by the microorganism or the infected cells are preferentially active on CD5 B cells, the resulting over-production of IL-10 will tend to bias all immune activities in to a Th-2mode of effector functions, with high titers of polyclonal antibodies and litle or no production of gamma IFN and other "inflamatory"lymphokines that often mediate resistance. In turn these conditions allow for parasite persistence and the corresponding long-term disregulation of self-directed immune reactivities, resulting in autoimmunity in the chronic phase. This model would predict that selective immunization with the mitogenic principles involved in desregulation, could stand better chances than strategies of vaccination based on immunopotentiation against othere, functionally neutral antigenic epitopes. It is argued, however, that the complexity of immune responses and their regulation together with our ignorance on the genetic controls of class-determination, offer poor prospects for a scientifically-based, rational development of vaccines in the near future. It is suggested that empirically-based and technologically developed vaccines might suceed, while basic scientific approaches are reinforced and given the time provide a better understanding of those process.