Behavior of Biomphalaria glabrata Say, 1818 (Gastropoda: Planorbidae): I. Morphophysiology of the Mantle Cavity

Using longitudinal and transverse anatomical sections, we observed that the three cristae of the mantle of Biomphalaria glabrata (renal, rectal and dorsolateral cristae) divide the mantle cavity into three chambers which we designated air or pulmonary chamber, water inflow chamber and water outflow chamber. Using videotape filming, we observed the inflow and outflow of air and water into and from the mantle cavity and we related their probable functions such as flotation, oxygen reservoir and transport, excreta circulation and elimination, water skeleton, and modification of specific weight. To determine whether the air bubble may function as a physical gill in this species we submitted three groups of snails to different systems in which water contained the same level of dissolved oxygen whereas the gas phases were atmospheric air, pure nitrogen or pure oxygen. We observed the following parameters: time of permanence on the surface, time of immersion, and frequency at which the snails reached the surface. These results did not demonstrate a physical gill function; morphological analysis of the mantle cavity indicates this possibility

Susceptibility of Nectomys rattus (Pelzen, 1883) to experimental infection with Schistosoma mansoni (Sambon, 1907): a potential reservoir in Brazil

The aim of the present research was to evaluate the potential of Nectomys rattus, the "water rat", to develop Schistosoma mansoni infection. Comparison with N. squamipes was carried out. Both species of rodents were submitted to transcutaneous infection using different infective cercariae loads: 50, 100 or 500. N. rattus showed high susceptibility to S. mansoni, with an infection rate of 71%. Rodents were able to excrete viable eggs of S. mansoni in the feaces during all infection period. For both species, the small intestine, followed by the liver and the large intestine, presented the highest concentration of eggs among the surveyed organs. Infection caused no animal death. Moreover, N. rattus accomplished the parasite's life cycle, by infecting the snails Biomphalaria glabrata and later Mus musculus. These evidences indicate that both N. rattus, as for N. squamipes are potential reservoirs for schistosomiasis in Brazil. Considering the fact that N. rattus and N. squamipes exist in the same natural ecosystems of S. mansoni, we suggest that these rodents must be regarded as influential factors in epidemiology surveys.

Plesiophysa guadeloupensis ("Fischer" Mazé, 1883)

A description is presented of the shell and anatomic characters of the planorbid mollusk Plesiophysa guadeloupensis ("Fischer" Mazé, 1883), based on topotypic specimens from a pond in Borricaud (Grande Terre, Guadeloupe). Comparison with previous descriptions of nominal species of Plesiophysa points to its identity with P. ornata (Haas, 1938), of which it is a senior synonym.

Physiological changes in Biomphalaria glabrata say, 1818 (Pulmonata: Planorbidae) caused by sub-lethal concentrations of the latex of Euphorbia splendens var. hislopii N.E.B (Euphorbiaceae)

Molluscides have been used as one of the strategies to control schistosomiasis. Many plant extracts with molluscidal effects have been tested, but the action of the latex of Euphorbia splendens var. hislopii is considered the most promising because it meets the recommendations of the World Health Organization (WHO). The objective of this study was to determine the lethal dose and identify the effects of the different doses of latex of E. splendens var. hislopii on the physiology of Biomphalaria glabrata submitted to treatment for 24 h. The concentrations of glucose, uric acid and total proteins in the hemolymph and of glycogen in the digestive gland and cephalopodal mass were determined. The LD50 value was 1 mg/l. The highest escape index was found to be at a concentration of 0.6 mg/l. The results showed that the latex of E. splendens var. hislopii caused a sharp reduction in the reserves of glycogen in the digestive gland and elevation of the protein content in the hemolymph of B. glabrata.

Changes induced in Biomphalaria glabrata (Say, 1818) following trials for artificial stimulation of its internal defense system

Biomphalaria glabrata can react through different pathways to Schistosoma mansoni miracidium penetration, according to the degree of resistance/susceptibility presented by different snail strains, which is a genetically determined character, resistance being the dominant feature. However, it has been observed that previous susceptible snail strain may change its reactive behavior along the course of infection, exhibiting later a pattern of cercarial shedding and histopatopathological picture compatible with high resistance. Such observation suggests the possibility of B. glabrata to develop a sort of adaptative immunity face a schistosome infection. To explore on this aspect, the present investigation looked for the behavior of S. mansoni infection in B. glabrata previously subjected to different means of artificial stimulation of its internal defense system. Snails previously inoculated with irradiated miracídia (Group I); treated with S. mansoni antigens (Group II) or with a non-related parasite antigen (Group III) were challenged with 20 viable S. mansoni miracidia, and later looked for cercarial shedding and histopathologic changes at different times from exposition. Nodules of hemocyte accumulations were found at the site of antigen injection. These nodules resembled solid granulomas, and were larger and more frequent in snails injected with S. mansoni products as compared to those injected with Capillaria hepatica. However, the presence of such granulomas did not avoid the S. mansoni challenge infection from developing in a similar way as that seen in controls. The data are indicative that hemocytes are able to proliferate locally when stimulated, such capacity also remaining localized, not being shared by the population of hemocytes located elsewhere within the snail body.

Incidência natural e biologia de Trichogramma atopovirilia Oatman & Platner, 1983 (Hymenoptera, Trichogrammatidae) em ovos de Anticarsia gemmatalis Hübner, 1818 (Lepidoptera, Noctuidae)

Trichogramma atopovirilia Oatman & Platner is an egg parasitoid of the corn earworm Helicoverpa zea (Boddie) (Lepidoptera, Noctuidae), and has recently been collected from eggs of Anticarsia gemmatalis Hübner on soybeans. In order to evaluate the suitability of A. gemmatalis eggs as hosts of T. atopovirilia, field surveys were conducted in 1999 and 2000 on corn and soybeans, and a colony of the parasitoid was established in laboratory. At 25 ºC, development from oviposition to emergence lasted nine days and a sex-ratio of 0.58 (females:males) was obtained. Females lived significantly longer (11.4 days) when kept in ovipositional activity, than in the absence of host eggs (6.6 days). Total fecundity averaged 104.5 parasitized eggs, resulting in the emergence of 138.3 descendents. Mean daily fecundity was highest (30 eggs/female) on the first day. Oviposition continued until one day before the death of the females, however 70% of the eggs were laid during the first four days after emergence. A female-biased progeny was produced during the first three days of oviposition, whereas further ovipositions were male-biased. Females lived significantly longer when exposed to host eggs in comparison to females deprived of eggs. The results show that eggs of A. gemmatalis are suitable for the development of T. atopovirilia, and this parasitoid should be considered in future programs of biological control of the velvetbean caterpillar.

Uma nova espécie de Strebla Wiedemann, 1824 (Diptera, Streblidae, Streblinae) sobre Anoura caudifer (E. Geoffroy, 1818) (Chiroptera, Phyllostomidae, Glossophaginae)

A new species of Strebla Wiedemann, S. carvalhoi sp. nov., collected, on Anoura caudifer (E. Geoffroy, 1818) from Southern of Brazil, is described. Drawings of the postvertex, occipital plates, gonopods and tergite VII are provided.

Utilização de índices r e R obtidos de programas interlaboratoriais para o controle de precisão de método analítico: Determinação de água por Karl Fischer

Values of repeatability (r) and reproducibility (R) are parameters of an analytical method. They are related to the maximum difference between two results of analysis (permissible range) and can be obtained by interlaboratorial comparisons. They represent great importance for the quality control of the results and decisions about the fitness-for-purpose of the method. Water determination in fuel oil samples were performed by 16 laboratories, using the Karl Fischer reaction, during the period from June 1997 to December 1999. Values of r and R were presented. Discussion is made in terms of the main factors that would be contribution to analytical method variabilities and uncertainties of final results.

De Hegel a Marx: da inflexão ontológica à antítese direta

Abordaremos a crítica marxiana à noção hegeliana de "ser" (Sein), mostrando que a historicidade e a objetividade, em verdade, são determinações desta (sendo as categorias, em Marx, formas de ser [Daseinsformen], determinações de existência [Existenzbestimmungen]). Deste modo, intentamos mostrar que analogias entre a lógica hegeliana e a teoria marxiana podem eclipsar aspectos centrais à abordagem materialista proposta pelo autor de "O capital". Apontando a inversão hegeliana entre sujeito e predicado, Marx trata da apreensão do real que, muito embora seja traçada em diálogo com a dialética hegeliana, é também sua antítese direta (direktes Gegenteil).

Epistemological anarchism of Paul Karl Feyerabend and medical education

The thoughts of the philosopher Paul Karl Feyerabend brought important contributions to the debate on Science in the 20th century. Most recently his views about non-existence of a single method for doing science have been employed to rethink science education and propose the use of multiple methods for effective teaching-learning process. This article employs the theoretical framework of the author expressed in the book Against Method, 1977, about the epistemological anarchism and the methodological pluralism and uses it in the contemporary discussion of medical education.

Estrutura morfológica do fígado de tambaqui Colossoma macropomum (Cuvier, 1818)

Este trabalho teve como objetivo descrever macro e microscopicamente o fígado do Tambaqui Colossoma macropomum, Teleósteo de água doce da Família Characidae, de grande interesse econômico da bacia Amazônica. Foram utilizados seis (6) exemplares jovens com idade entre seis meses e um ano, oriundos da Chácara Esteio, Alta Floresta, MT, que desenvolve principalmente a prática da piscicultura. O órgão foi fotodocumentado in situ e descrito macroscopicamente, em seguida procedeu-se a retirada de fragmentos deste, que foram processados pelas técnicas histológicas rotineiras para inclusão em parafina e coloração de HE. O fígado localizou-se ventral à bexiga natatória e craniodorsalmente ao estômago, apresentou coloração amarronzada a vermelho, constituído por três lobos hepáticos, o lobo lateral direito, o lobo lateral esquerdo e o lobo ventral. Microscopicamente, o parênquima era constituído por hepatócitos com formato que variou do arredondado irregular hexagonal ao redondo com núcleo grande e central, arranjados em cordões lineares limitados por sinusóides que irradiam para veias centrais, e com ausência de lóbulos hepáticos. As veias centrais estavam distribuídas pelo parênquima, enquanto que o espaço porta, na maioria das vezes, era constituído apenas por uma veia hepática e o ducto biliar, em outros locais foi observado, uma artéria e um ducto. Não foi observada a formação de tríades portais. Foram frequentemente observados melano macrófagos centrais dispersos pelo parênquima. O estudo morfofuncional do Aparelho Digestório de peixes da bacia Amazônica, se faz pertinente com vistas ao conhecimento do aproveitamento de ganho de peso e produção em alta escala para consumo humano e preservação da espécie, além da importância de estarem sendo utilizados como bioindicadores atualmente.

Karl Polanyi, Athens and us: the contemporary significance of Polanyi's thought

Karl Polanyi is considered one of the most prominent social scientists of the 20th century. In his writings, an important concern was the relationship between the markets and the society (therefore, the state) as a whole; to discuss it, he introduced the concept of "embeddedness", fundamental for his study of the origins and consequences of the Industrial Revolution. An important part of his heritage is the study of the economic history of what he called "ancient societies," especially of Classical Greece. Polanyi used these studies to compare the ancient societies with his own times, in an effort to understand them all. This paper aims to relate Polanyi's work on the Athenian society with his studies about the modern times, showing that it is possible to draw lessons from Polanyi's thought on the relationship between the society, the state and the market that can help to design a political agenda for our days. In the first part, we present the most important aspects o the life and work of Polanyi, and in the second we discuss the most important aspects of his worldview. Then, in the third part, we study his view of the early Athenian economy; mainly, we focus on the coexistence of a kind of state planning and a market, showing how this understanding is crucial for the whole Polanyian legacy, with its emphasis in the comparison of different societies and times. We conclude by underlining the relevance of this interpretation advanced by Polanyi to understand the societies of our days, focusing on some proposals to extend his approach to deal with our contemporary problems.

Causa e efeito: contribuições de Marx para investigações sobre finanças e inovação

Marx has a method for the evaluation of patterns of interaction between finance and innovation. Two starting points of this method are the simultaneity of cause and effect and the identification of reciprocal effects between the monetary-financial dimension and the industrial-innovative dimension. This paper investigates this method firstly defining a dynamic concept of money. The connections between the monetary-financial dimension and the industrial-innovative dimension are examined through their historical and theoretical elements. Finally, the most important connections of this complex interaction are presented.

Marx, o cínico?

Este artigo foi escrito em agosto/83, para conferência-debate na Jornada de Filosofia da UNESP (Campus de Marília, setembro de 1983). Partindo de aproximações Marx/Hegel sobre o tema da "fatalidade histórica", passamos a discutir a reprodução da força de trabalho como parte do capital, entendido este último, por sua vez, como relação social. Este exame é feito na esteira de algumas passagens de O Capital e dos Grundrisse. A seguir, procedemos à leitura de alguns fatos contemporâneos à luz dessa "anatomia cínica".

A interpretação do Proslogion por Karl Barth

O objetivo principal deste texto é apresentai alguns elementos essenciais da interpretação do Proslogion feita por Karl Barth em seu livro S. Anselme, Fides Quaerens Intellectum. La preuve de l'existence de Dieu (trad. franc). Com Base no "programa teológico" de Anselmo, Barth identifica as linhas fundamentais para a leitura dos capítulos 2 a 4 do Pioslogion. Tentaremos mostrar a significação e o alcance dessa interpretação para a historiografia do pensamento anselmiano.