On the structural organization of the bacillary band of Trichuris muris under cryopreparation protocols and three-dimensional electron microscopy.

Whipworms of the genus Trichuris are nematode parasites that infect mammals and can lead to various intestinal diseases of human and veterinary interest. The most intimate interaction between the parasite and the host intestine occurs through the anterior region of the nematode body, inserted into the intestinal mucosa during infection. One of the most prominent structures of the nematode surface found at the infection site is the bacillary band, a surface domain formed by a number of cells, mostly stichocytes and bacillary glands, whose structure and function are still under debate. Here, we used confocal microscopy, field emission scanning electron microscopy, helium ion microscopy, transmission electron microscopy and FIB-SEM tomography to unveil the functional role of the bacillary gland cell. We analyzed the surface organization as well as the intracellular milieu of the bacillary glands of Trichuris muris in high pressure frozen/freeze-substituted samples. Results showed that the secretory content is preserved in all gland openings, presenting a projected pattern. FIB-SEM analysis showed that the lamellar zone within the bacillary gland chamber is formed by a set of lacunar structures that may exhibit secretory or absorptive functions. In addition, incubation of parasites with the fluid phase endocytosis marker sulforhodamine B showed a time-dependent uptake by the parasite mouth, followed by perfusion through different tissues with ultimate secretion through the bacillary gland. Taken together, the results show that the bacillary gland possess structural characteristics of secretory and absorptive cells and unequivocally demonstrate that the bacillary gland cell functions as a secretory structure.

Boehmiella wilsoni (Nematoda, Heligmosomoidea, Boehmiellidae fam. nov.), found in Amazonian rodents.

The genus Boehmiella was initially described as a member of the family Trichostrongylidae. Subsequently, it was assigned to the subfamily Haemonchinae in the family Haemonchidae. We analyzed parasites of spiny tree-rats, Mesomys hispidus, collected in the Amazon rainforest, which were identified as B. wilsoni based on integrative taxonomy. Using morphology, morphometry, and scanning electron microscopy (SEM), we added new data to the original description of the species. We also inferred phylogenetic hypotheses for its relationships within the Trichostrongylina, based on partial nuclear 18S and 28S rRNA genes, through Maximum Likelihood and Bayesian analyses. In conclusion, B. wilsoni does not belong to the family Haemonchidae, nor is it closely related to any other trichostrongylin family, and therefore, we propose the establishment of a new family, Boehmiellidae fam. nov., to which the genus Boehmiella is allocated.

Eurytrema coelomaticum: updated morphology of adult worms using advanced microscopy experiments.

Eurytrema coelomaticum is a digenean flatworm of ruminants that is the causative agent of eurytrematosis, a disease of veterinary health concern. Although modern techniques of morphological analysis have provided new insights about the morphology and anatomy of parasitic helminths, most studies on E. coelomaticum adults are based on conventional light microscopy. In the present study, a combined approach using brightfield, fluorescence, confocal and scanning electron microscopies (SEMs), together with the cryofracture technique, have updated morphological data on E. coelomaticum recovered from cattle in Rio de Janeiro State, Brazil. Light microscopy confirmed the presence of several structures present in the current description, such as suckers, pharynx, oesophagus, intestinal bifurcation and the cirrus-sac. Fluorescence stereomicroscopy revealed for the first time the cubic crystal protein inclusions in the forebody, which were further detailed by confocal and SEMs. Confocal microscopy provided detailed information of the muscular architecture associated with the attachment structures (suckers), digestive system (pharynx and oesophagus), egg-forming complex (ovary, Mehlis' gland and Laurer's canal) and male reproductive system, which are similar to those found in other digenean flukes. SEM images of cryofractured parasites showed mucus and developing eggs within uterine loops. It was demonstrated that the combination of advanced tools generated complementary information, confirming the importance of experimental morphology in parasitology. Therefore, the knowledge of the adult structural organization of E. coelomaticum was improved and this work has contributed to propose new morphological criteria to evaluate the effects of antiparasitic drugs on flukes of medical and veterinary importance.

First record of Bulimulus tenuissimus (Mollusca) as potential experimental intermediate host of Angiostrongylus cantonensis (Nematoda) / Primeiro registro de Bulimulus tenuissimus (Mollusca) como hospedeiro intermediário de Angiostrongylus cantonensis (Nematoda)

Abstract Snails are essential to complete the life cycle of the metastrongylid nematode Angiostrongylus cantonensis, the causative agent of infections in domestic and wild animals, mainly rodents, and also of neural angiostrongyliasis or eosinophilic meningitis in humans. There are many reports of mollusks that can act as intermediate hosts of this parasite, especially freshwater snails and the African giant Achatina fulica. The terrestrial gastropod Bulimulus tenuissimus is widely distributed in Brazil and other species of the same genus occur in Brazil and other countries, overlapping regions in which there are reports of the occurrence of A. cantonensis and angiostrongyliasis. In spite of this, there are no records in the literature of this species performing the role of intermediate host to A. cantonensis. The present study analyzed the experimental infection with first-stage larvae of A. cantonensis, under laboratory conditions, of B. tenuissimus, by using histology and electron microscopy techniques. Three weeks after exposure to L1 larvae, it was possible to recover L3 larvae in small numbers from the infected snails. Developing larvae were observed in the cephalopedal mass (foot), ovotestis, and mantle tissues, being located inside a granulomatous structure composed of hemocyte infiltration, but there was no calcium or collagen deposition in these structures in significant amounts. In the third week post exposure, it was possible observe a sheath around the developing larvae. The infected snails presented reduction in the fibrous muscular tissue in the foot region, loss of the acinar organization in the digestive gland, with increase of amorphous material inside the acini and loss of epithelial pattern of nuclear organization in the acinar cells. However, the ovotestis seemed unaffected by the infection, since there was a large number of developing oocytes and spermatozoa in different stages of formation. The digestion of infected snails allows us the third-stage recovery rate of 17.25%, at 14 days post exposure to the L1. These L3 recovered from B. tenuissimus were used to infect rats experimentally, and 43 days post infection first-stage (L1) larvae of A. cantonensis were recovered from fresh feces. The results presented constituted the first report of the role of B. tenuissimus as an experimental intermediate host to A. cantonensis and shed some light on a possible problem, since the overlapping distribution of B. tenuissimus and A. cantonensis in Brazil and other countries where different species of Bulimulus occur enables the establishment and maintenance of the life cycle of this parasite in nature, with wild rodents as reservoirs, acting as a source of infection to humans, causing neural angiostrongyliasis.

Resumo Os moluscos são um requisito essencial para a conclusão do ciclo de vida pelo nematoide metastrogilídeo Angiostrongylus cantonensis, o agente causador de infecções em animais domésticos e selvagens, principalmente roedores, e também de angiostrongilíase neural ou meningite eosinofílica em humanos. Há muitos relatos de moluscos que podem atuar como hospedeiro para este parasito, sendo o foco dado aos moluscos de água doce e no gigante africano Achatina fulica. O gastrópode terrestre Bulimulus tenuissimus é amplamente distribuído no território brasileiro e há outras espécies do mesmo gênero que ocorrem no Brasil e outros países, sobrepondo-se às regiões em que há relatos à ocorrência de A. cantonensis e angiostornigilíase. Apesar disso, não há registro na literatura, acerca desta espécie como hospedeiro intermediário para A. cantonensis. O presente estudo teve como objetivo verificar a possibilidade de infectar experimentalmente, utilizando larvas L1 de A. cantonensis, em condições laboratoriais, o molusco B. tenuissimus, utilizando técnicas de histologia e microscopia eletrônica. Três semanas após a exposição às larvas L1, foi possível recuperar larvas L3 dos moluscos infectados, em pequena quantidade. As larvas em desenvolvimento foram observadas na massa cefalopediosa (pé), ovotestis e nos tecidos do manto, sendo localizadas dentro de uma estrutura granulomatosa constituída por infiltração hemocitária, mas não houve deposição de cálcio ou colágeno nessas estruturas em quantidade significativa. Na terceira semana pós exposição, foi possível observar uma bainha ao redor das larvas em desenvolvimento. Os caracóis infectados apresentaram redução no tecido muscular fibroso na região do pé, perda da organização acinar na glândula digestiva, com aumento de material amorfo dentro dos ácinos e perda do padrão epitelial da organização nuclear nas células acinares. No entanto, o ovotestis, pareceu não ser afetado pela infecção, uma vez que houve um grande número de oócitos em desenvolvimento e espermatozóides em diferentes estágios de formação. A digestão dos moluscos infectados nos permitiu a recuperação de larvas de terceiro estágio (17,25%), aos 14 dias após a exposição à L1 de A. cantonensis . Estas L3 recuperadas de B. tenuissimus foram utilizados para infectar ratos experimentalmente, e 43 dias após a infecção, as larvas do primeiro estágio (L1) foram recuperadas de fezes frescas. Os resultados apresentados representam o primeiro registro do papel de B. tenuissimus como hospedeiro intermediário experimental de A. cantonensis e trazem alguma luz a um problema, até então silencioso, uma vez que a sobreposição da distribuição de B. tenuissimus e A. cantonensis no Brasil, e outros países, onde as diferentes espécies de Bulimulus ocorrem, torna possível o estabelecimento e manutenção do ciclo de vida deste parasito na natureza, com roedores selvagens como reservatório, agindo como fonte de infecção para humanos e causando a angiostrongilíase neural.

Xiphidiocercariae from naturally infected Lymnaea columella (Mollusca, Gastropoda) in urban area: morphology and ultrastructure of the larvae and histological changes in the mollusc host / Xifidiocercárias obtidas em Lymnaea columella (Mollusca, Gastropoda) naturalmente infectadas em área urbana: morfologia e ultraestrutura da larva e alterações histológicas do molusco hospedeiro

Abstract Urban agriculture is very common in the cities, as Rio de Janeiro and adjacencies, being important as economic activity. However, this practice can create appropriate conditions for establishment and maintenance of life cycle of many parasites. Lymneid snails can act as intermediate hosts of many trematodes species, including those that infect humans and wild and domestic. In the present study, the snail Lymnaea columella was collected from an urban watercress plantations and the morphology of cercariae released by them was analyzed by light and scanning electron microscopy. The specimens were identified as xiphidiocercariae, belonging to the Cercariae Ornatae group, of the order Plagiorchiiformes. Histological examination of the digestive gland of the infected snails revealed the presence of developing sporocysts, with hemocitary infiltration and metaplasia in the epithelial tissue.

Resumo Agricultura urbana é muito comum nas cidades, como Rio de Janeiro e adjacências, sendo uma importante atividade econômica de subsistência. No entanto, esta prática pode criar condições adequadas para o estabelecimento e manutenção do ciclo de vida de muitos parasitos. Os moluscos limneídeos podem atuar como hospedeiros intermédios de muitas espécies de trematódeos, incluindo aqueles que infectam humanos e animais selvagens e domésticos. No presente estudo, o molusco Lymnaea columella foi coletado de plantações urbanas de agrião e a morfologia das cercárias liberadas por eles foi analisada por microscopia eletrônica de varredura leve e de varredura. As larvas foram identificadas como xifidiocercárias, pertencentes ao grupo das Cercariae Ornatae, Ordem Plagiorchiiformes. Análises histológicas da glândula digestiva dos moluscos infectados evidenciaram esporocistos, com formação de granuloma e metaplasia do tecido epitelial.

Taxonomy of Physaloptera mirandai (Nematoda: Physalopteroidea) based in three-dimensional microscopy and phylogenetic positioning.

Gastrointestinal nematodes are important ecological assets for the maintenance of the biodiversity in the Atlantic Forest in Brazil. They parasitize a number of animals of the local fauna, in which some species can promote serious injuries in the stomach wall of their hosts, which may lead to death. Among these nematodes, parasites of the genus Physaloptera are known to parasitize mammals (particularly carnivores and small rodents), birds and reptiles, being important for the local biodiversity. In this work, three hundred and sixty-two nematodes were recovered from the stomach of twenty-one Metachirus nudicaudatus (Didelphimorphia: Didelphidae) collected in Duas Bocas Biological Reserve, State of Espírito Santo, one of the largest Atlantic Forest remnants and important wildlife refuge of the Atlantic Forest in Brazil. Analysis using fluorescence and scanning electron microscopy as well as phylogenetic assessment using the mitochondrial cytochrome c oxidase subunit I gene showed that the parasites belong to the Physaloptera. Our results show details of the nematode morphology including the cloacal papillae distribution, cuticular topography details, 2D and 3D measurements of the structures with taxonomic importance. Molecular data confirmed the validity of P. mirandai and the phylogeny supported the monophyly of the assemblage formed by Physaloptera and Turgida. The use of a combination of quantitative and multidimensional microscopy tools, such as 3D reconstruction and modeling, allied to phylogenetic analysis may provide grounds for a new approach on helminth taxonomy and structural characterization.

First record of Bulimulus tenuissimus (Mollusca) as potential experimental intermediate host of Angiostrongylus cantonensis (Nematoda).

Snails are essential to complete the life cycle of the metastrongylid nematode Angiostrongylus cantonensis, the causative agent of infections in domestic and wild animals, mainly rodents, and also of neural angiostrongyliasis or eosinophilic meningitis in humans. There are many reports of mollusks that can act as intermediate hosts of this parasite, especially freshwater snails and the African giant Achatina fulica. The terrestrial gastropod Bulimulus tenuissimus is widely distributed in Brazil and other species of the same genus occur in Brazil and other countries, overlapping regions in which there are reports of the occurrence of A. cantonensis and angiostrongyliasis. In spite of this, there are no records in the literature of this species performing the role of intermediate host to A. cantonensis. The present study analyzed the experimental infection with first-stage larvae of A. cantonensis, under laboratory conditions, of B. tenuissimus, by using histology and electron microscopy techniques. Three weeks after exposure to L1 larvae, it was possible to recover L3 larvae in small numbers from the infected snails. Developing larvae were observed in the cephalopedal mass (foot), ovotestis, and mantle tissues, being located inside a granulomatous structure composed of hemocyte infiltration, but there was no calcium or collagen deposition in these structures in significant amounts. In the third week post exposure, it was possible observe a sheath around the developing larvae. The infected snails presented reduction in the fibrous muscular tissue in the foot region, loss of the acinar organization in the digestive gland, with increase of amorphous material inside the acini and loss of epithelial pattern of nuclear organization in the acinar cells. However, the ovotestis seemed unaffected by the infection, since there was a large number of developing oocytes and spermatozoa in different stages of formation. The digestion of infected snails allows us the third-stage recovery rate of 17.25%, at 14 days post exposure to the L1. These L3 recovered from B. tenuissimus were used to infect rats experimentally, and 43 days post infection first-stage (L1) larvae of A. cantonensis were recovered from fresh feces. The results presented constituted the first report of the role of B. tenuissimus as an experimental intermediate host to A. cantonensis and shed some light on a possible problem, since the overlapping distribution of B. tenuissimus and A. cantonensis in Brazil and other countries where different species of Bulimulus occur enables the establishment and maintenance of the life cycle of this parasite in nature, with wild rodents as reservoirs, acting as a source of infection to humans, causing neural angiostrongyliasis.

Xiphidiocercariae from naturally infected Lymnaea columella (Mollusca, Gastropoda) in urban area: morphology and ultrastructure of the larvae and histological changes in the mollusc host.

Urban agriculture is very common in the cities, as Rio de Janeiro and adjacencies, being important as economic activity. However, this practice can create appropriate conditions for establishment and maintenance of life cycle of many parasites. Lymneid snails can act as intermediate hosts of many trematodes species, including those that infect humans and wild and domestic. In the present study, the snail Lymnaea columella was collected from an urban watercress plantations and the morphology of cercariae released by them was analyzed by light and scanning electron microscopy. The specimens were identified as xiphidiocercariae, belonging to the Cercariae Ornatae group, of the order Plagiorchiiformes. Histological examination of the digestive gland of the infected snails revealed the presence of developing sporocysts, with hemocitary infiltration and metaplasia in the epithelial tissue.

First record of Bulimulus tenuissimus (Mollusca) as potential experimental intermediate host of Angiostrongylus cantonensis (Nematoda)

Abstract Snails are essential to complete the life cycle of the metastrongylid nematode Angiostrongylus cantonensis, the causative agent of infections in domestic and wild animals, mainly rodents, and also of neural angiostrongyliasis or eosinophilic meningitis in humans. There are many reports of mollusks that can act as intermediate hosts of this parasite, especially freshwater snails and the African giant Achatina fulica. The terrestrial gastropod Bulimulus tenuissimus is widely distributed in Brazil and other species of the same genus occur in Brazil and other countries, overlapping regions in which there are reports of the occurrence of A. cantonensis and angiostrongyliasis. In spite of this, there are no records in the literature of this species performing the role of intermediate host to A. cantonensis. The present study analyzed the experimental infection with first-stage larvae of A. cantonensis, under laboratory conditions, of B. tenuissimus, by using histology and electron microscopy techniques. Three weeks after exposure to L1 larvae, it was possible to recover L3 larvae in small numbers from the infected snails. Developing larvae were observed in the cephalopedal mass (foot), ovotestis, and mantle tissues, being located inside a granulomatous structure composed of hemocyte infiltration, but there was no calcium or collagen deposition in these structures in significant amounts. In the third week post exposure, it was possible observe a sheath around the developing larvae. The infected snails presented reduction in the fibrous muscular tissue in the foot region, loss of the acinar organization in the digestive gland, with increase of amorphous material inside the acini and loss of epithelial pattern of nuclear organization in the acinar cells. However, the ovotestis seemed unaffected by the infection, since there was a large number of developing oocytes and spermatozoa in different stages of formation. The digestion of infected snails allows us the third-stage recovery rate of 17.25%, at 14 days post exposure to the L1. These L3 recovered from B. tenuissimus were used to infect rats experimentally, and 43 days post infection first-stage (L1) larvae of A. cantonensis were recovered from fresh feces. The results presented constituted the first report of the role of B. tenuissimus as an experimental intermediate host to A. cantonensis and shed some light on a possible problem, since the overlapping distribution of B. tenuissimus and A. cantonensis in Brazil and other countries where different species of Bulimulus occur enables the establishment and maintenance of the life cycle of this parasite in nature, with wild rodents as reservoirs, acting as a source of infection to humans, causing neural angiostrongyliasis.

Resumo Os moluscos são um requisito essencial para a conclusão do ciclo de vida pelo nematoide metastrogilídeo Angiostrongylus cantonensis, o agente causador de infecções em animais domésticos e selvagens, principalmente roedores, e também de angiostrongilíase neural ou meningite eosinofílica em humanos. Há muitos relatos de moluscos que podem atuar como hospedeiro para este parasito, sendo o foco dado aos moluscos de água doce e no gigante africano Achatina fulica. O gastrópode terrestre Bulimulus tenuissimus é amplamente distribuído no território brasileiro e há outras espécies do mesmo gênero que ocorrem no Brasil e outros países, sobrepondo-se às regiões em que há relatos à ocorrência de A. cantonensis e angiostornigilíase. Apesar disso, não há registro na literatura, acerca desta espécie como hospedeiro intermediário para A. cantonensis. O presente estudo teve como objetivo verificar a possibilidade de infectar experimentalmente, utilizando larvas L1 de A. cantonensis, em condições laboratoriais, o molusco B. tenuissimus, utilizando técnicas de histologia e microscopia eletrônica. Três semanas após a exposição às larvas L1, foi possível recuperar larvas L3 dos moluscos infectados, em pequena quantidade. As larvas em desenvolvimento foram observadas na massa cefalopediosa (pé), ovotestis e nos tecidos do manto, sendo localizadas dentro de uma estrutura granulomatosa constituída por infiltração hemocitária, mas não houve deposição de cálcio ou colágeno nessas estruturas em quantidade significativa. Na terceira semana pós exposição, foi possível observar uma bainha ao redor das larvas em desenvolvimento. Os caracóis infectados apresentaram redução no tecido muscular fibroso na região do pé, perda da organização acinar na glândula digestiva, com aumento de material amorfo dentro dos ácinos e perda do padrão epitelial da organização nuclear nas células acinares. No entanto, o ovotestis, pareceu não ser afetado pela infecção, uma vez que houve um grande número de oócitos em desenvolvimento e espermatozóides em diferentes estágios de formação. A digestão dos moluscos infectados nos permitiu a recuperação de larvas de terceiro estágio (17,25%), aos 14 dias após a exposição à L1 de A. cantonensis . Estas L3 recuperadas de B. tenuissimus foram utilizados para infectar ratos experimentalmente, e 43 dias após a infecção, as larvas do primeiro estágio (L1) foram recuperadas de fezes frescas. Os resultados apresentados representam o primeiro registro do papel de B. tenuissimus como hospedeiro intermediário experimental de A. cantonensis e trazem alguma luz a um problema, até então silencioso, uma vez que a sobreposição da distribuição de B. tenuissimus e A. cantonensis no Brasil, e outros países, onde as diferentes espécies de Bulimulus ocorrem, torna possível o estabelecimento e manutenção do ciclo de vida deste parasito na natureza, com roedores selvagens como reservatório, agindo como fonte de infecção para humanos e causando a angiostrongilíase neural.

Redescription of Spirura guianensis (Nematoda: Spiruridae) from a rare South American Gracile Opossum.

Spirura genus Blanchard, 1849 comprise of nematode parasites that infect primate and marsupial species. Although several taxonomical studies have shown that the infection by this species occurs primarily in the esophagus of primates, evidence for the occurrence of these parasites in other hosts (marsupials, rodents and bats) has become the subject of investigation by several groups. In this work, we describe the presence of Spirura guianensis Ortlepp, 1924 in the marsupial Gracilinanus agilis (Marsupialia: Didelphidae) found in the Pantanal of Mato Grosso do Sul state of Brazil. Structural characteristics of this nematode were identified using light microscopy (bright field and fluorescence stereomicroscopy) and scanning electron microscopy (SEM) approaches. Details of the surface topography such as cephalic projections, ventral boss, details of the caudal papillae and cuticular ornamentations were shown, providing taxonomic characteristics that may help in the establishment of diagnostic protocols. In addition, the presence of this species in a new host and new geographical area of Brazil provide grounds for a revision on the distribution of S. guianensis in South America.

The giant African snail Achatina fulica as natural intermediate host of Angiostrongylus cantonensis in Pernambuco, northeast Brazil.

The human cases of eosinophilic meningitis recently reported from Brazil have focused the attention of the public health agencies on the role the introduced snail Achatina fulica plays as hosts of the metastrongylid nematodes. Determining the potential of this snail to host and develop infective larval stages of metastrongylids in the wild and identify the species harbored by them is crucial for designing effective control measures. Here we assess if A. fulica may act as intermediate host of A. cantonensis at the peridomiciliary areas of a patient's house from state of Pernambuco (PE), who was diagnosed with eosinophilic meningitis and a history of ingesting raw molluscs. Larvae obtained from naturally infected A. fulica were orally administered to Rattus norvegicus. The worms were collected from the pulmonary artery and brain, and were morphologically characterized and compared to the Japan isolate of A. cantonensis. Adult worms and infective L(3) larvae (PE isolate) recovered from A. fulica specimens were also analyzed by polymerase chain reaction and restriction fragment length polymorphism of ITS2 region from rDNA and compared to A. cantonensis (ES isolate), A. vasorum (MG isolate) and A. costaricensis (RS isolate). The large size of the spicules (greater than those observed in other species of Angiostrongylus) and the pattern of the bursal rays agree with the original species description by Chen (1935). Furthermore, the morphology of the PE isolate was similar to that of Japan isolate. The PCR-RFLP profiles obtained were distinctive among species and no variation in patterns was detected among adult individuals from A. cantonensis isolates from PE and ES. The importance of A. fulica as an intermediate host of eosinophilic menigoencepahlitis in Brazil is emphasized.

Spirurids from Gracilinanus agilis (Marsupialia: Didelphidae) in Brazilian Pantanal wetlands with a new species of Physaloptera (Nematoda: Spirurida).

Gastrointestinal nematodes were recovered from thirty four Gracilinanus agilis from forty four collected in Pantanal, Mato Grosso do Sul State, Brazil. Two hundred seventy four spirurids were recovered from the esophagus, stomach and intestines, comprising three species from three different genera. These were identified as Pterygodermatites (Paucipectines) jägerskiöldi, Spirura guianensis and Physaloptera herthameyerae n. sp. is first described. This is the first record of nematodes of the genera Physaloptera and Spirura in hosts of the genus Gracilinanus. The high prevalence of spirurids in 72.3% of the G. agilis collected probably is influenced by the arboreal and diet behaviors.

Nematode cysts and larvae found in Achatina fulica Bowdich, 1822.

This study describes the morphology of the nematode cysts and larvae found in Achatina fulica (giant African snail) in Brazil. Sixty snails were collected in Mesquita, Rio de Janeiro State. Fourteen of the snails were naturally infected. The cysts were spherical, pink colored and measured 0.97 to 1.57 mm in diameter. In the majority of cases they had a single larvae involved in amorphous material. A total of 222 encysted larvae were recovered. Of these, 30 were utilized in the morphological study. The length of the larvae varied from 2.57 to 5.8 mm and they were classified as small--up to 3.5 mm; medium--from 3.53 to 4.5 mm; and large--greater than 4.52 mm. The average length of the larvae in the three groups was 2.85, 3.87 and 5.23 mm, respectively. The larval cuticle was white, shiny and transversally striated until the posterior end of the body. At the anterior end there is a mouth with three lips, with amphids and papillae, followed by a muscular esophagus with average length of 0.61 mm, terminating in an esophageal bulb and having a nerve ring in the middle third of the esophagus, and an intestine with an opening near the posterior end. The tail begins from this opening and has two types of ends: short and abrupt or long and gradually tapering. The difference in the tail end can suggest sexual dimorphism, although no primordial reproductive structures were observed. These characteristics were not sufficient to identify the larvae, so there is a need for further study.

Limitations of an oscillometric ambulatory blood pressure monitor in physically active children.

OBJECTIVE: To determine the limitations of an oscillometric device for measuring ambulatory blood pressure in physically active children. DESIGN: Observational descriptive. SUBJECTS: Sixty-one children 4.3 to 18.7 years of age. INTERVENTIONS: Twenty-two high school students wore an ambulatory blood pressure monitor (SpaceLabs model 90202) for 24 hours. A subject-kept activity diary facilitated data interpretation. In 39 additional subjects, measurements were recorded during strenuous exercise, at rest, and after ambulation. Before and after the students wore the unit, oscillometric and auscultatory blood pressure measurements were simultaneously taken to calibrate the ambulatory blood pressure monitor, evaluate its accuracy, and assess deterioration in the calibration of the unit with use. RESULTS: During 24-hour ambulatory monitoring, 29% of the readings were edited because of error codes, primarily because of vibratory interference. At the end of the 24-hour monitoring period, simultaneous pressures by oscillometric and auscultatory techniques agreed within 6 mm Hg in 17 of 18 cases for both systolic and diastolic blood pressures. During exercise, 88.4% of the systolic and diastolic blood pressure readings agreed within 8 mm Hg. In 20 other ambulatory subjects with 80 simultaneous oscillometric and auscultatory measurements, all systolic and 88.5% of the diastolic values agreed within 10%. CONCLUSIONS: These results indicate that the SpaceLabs model 90202 unit provides a reasonably accurate assessment of ambulatory blood pressures in mildly active and inactive children and that blood pressure can be monitored with time.

Natriuresis during and early after cardiopulmonary bypass: relationship to atrial natriuretic factor, aldosterone, and antidiuretic hormone.

Because neurohumoral responses to cardiopulmonary bypass (CPB) are similar to those seen in shock, CPB might be expected to decrease renal blood flow; yet diuresis is commonly observed during and early after routine cardiac procedures with CPB. To examine this apparent paradox, we studied 15 patients before, during, and after CPB for coronary artery bypass grafting. Plasma levels of atrial natriuretic factor (alpha-ANF), aldosterone, and antidiuretic hormone (ADH) and urinary sodium excretion were measured before anesthesia, after sternotomy but before CPB, at 15 and 30 minutes of CPB, and at 15 and 30 minutes after discontinuation of CPB. alpha-ANF increased only slightly during CPB, and the initial natriuresis during CPB occurred in the presence of a markedly increased ADH level. After CPB ended, urine flow and sodium excretion increased in conjunction with increased alpha-ANF and normal ADH. We conclude that the early natriuresis during CPB occurs in the presence of a high ADH concentration, with no significant increase in plasma alpha-ANF. This may be a paradoxic response to supraphysiologic levels of ADH. The natriuresis after CPB appears to be strongly associated with increased alpha-ANF, present for at least the first 30 minutes after CPB, which could reflect alpha-ANF release resulting from atrial distention during volume loading.

Estimacion de la velocidad de filtracion glomerular por un metodo simple en recien nascidos normales. / Evaluation of the glomerular filtration rate by a simple method in normal newborn infants

Se analiza la velocidad de filtracion glomerular (VFG) en 45 recien nacidos a termino (RNT) sanos empleando una formula empirica donde: VFG (ml/min/1.73m2 S.C.) = 0.55 x Talla/Crp. En esta ecuacion la talla se expresa en centimetros y Crp es creatinina plasmatica. La VFG se determino al momento del nacimiento tomando sangre del cordon para medir Crp, a los 8 y 30 dias de edad. El primer dia de nacido la VFG fue en promedio de 50.2 ml/min/1.73m2 S.C., a los 8 dias de edad no se observo un aumento significativo y el valor promedio fue de 53.1 +/- 30 ml/min/1.73 m2 S.C.A los 30 dias de edad la VFG experimento un incremento significativo, 65.1 +/- 24 ml/min/1.73m2 S.C., en relacion con el primer y el octavo dia de edad, p < 0.02.Nuestras observaciones senalan que la VFG es baja en RNT aun a los 30 dias de edad.Se analizan los factores que podrian condicionar esta disminucion