Buccal jet streaming and dead space determination in the South American lungfish, Lepidosiren paradoxa.

The "jet stream" model predicts an expired flow within the dorsal part of the buccal cavity with small air mixing during buccal pump ventilation, and has been suggested for some anuran amphibians but no other species of air breathing animal using a buccal force pump has been investigated. The presence of a two-stroke buccal pump in lungfish, i.e. expiration followed by inspiration, was described previously, but no quantitative data are available for the dead-space of their respiratory system and neither a detailed description of airflow throughout a breathing cycle. The present study aimed to assess the degree of mixing of fresh air and expired gas during the breathing cycle of Lepidosiren paradoxa and to verify the possible presence of a jet stream during expiration in this species. To do so, simultaneous measurements of buccal pressure and ventilatory airflows were carried out. Buccal and lung gases (PCO2 and PO2) were also measured. The effective ventilation was calculated and the dead space estimated using Bohr equations. The results confirmed that the two-stroke buccal pump is present in lungfish, as it is in anuran amphibians. The present approaches were coherent with a small dead space, with a very small buccal-lung PCO2 difference. In the South American lungfish the dead space (VD) as a percentage of tidal volume (VT) (VD / VT) ranged from 4.1 to 12.5%. Our data support the presence of a jet stream and indicate a small degree of air mixing in the buccal cavity. Comparisons with the literature indicate that these data are similar to previous data reported for the toad Rhinella schneideri.

Neural regeneration dynamics of Xenopus laevis olfactory epithelium after zinc sulfate-induced damage.

Neural stem cells (NSCs) of the olfactory epithelium (OE) are responsible for tissue maintenance and the neural regeneration after severe damage of the tissue. In the normal OE, NSCs are located in the basal layer, olfactory receptor neurons (ORNs) mainly in the middle layer, and sustentacular (SUS) cells in the most apical olfactory layer. In this work, we induced severe damage of the OE through treatment with a zinc sulfate (ZnSO4) solution directly in the medium, which resulted in the loss of ORNs and SUS cells, but retention of the basal layer. During recovery following injury, the OE exhibited increased proliferation of NSCs and rapid neural regeneration. After 24h of recovery, new ORNs and SUS cells were observed. Normal morphology and olfactory function were reached after 168h (7 days) of recovery after ZnSO4 treatment. Taken together, these data support the hypothesis that NSCs in the basal layer activate after OE injury and that these are sufficient for complete neural regeneration and olfactory function restoration. Our analysis provides histological and functional insights into the dynamics between olfactory neurogenesis and the neuronal integration into the neuronal circuitry of the olfactory bulb that restores the function of the olfactory system.

The electrosensorial pore system of the cephalofoil in the four most common species of hammerhead shark (Elasmobranchii: Sphyrnidae) from the Southwestern Atlantic.

The laterally expanded head is the principal character distinguishing hammerhead sharks, and its morphology is important for interpreting their ontogeny and species diversity. Because their head shape changes during its ontogeny, it is vital to evaluate it in order to establish other taxonomical characteristics to correctly identify Sphyrna species. This study examines the distribution of electrosensorial pore regions on the ventral surface of the cephalofoil (VSC) in Sphyrna lewini, S. tiburo, S. tudes and S. zygaena from the Southwestern Atlantic Ocean. The pore distribution patterns in the VSC can distinguish these species. Use of those patterns, with the head shape, confirms the identification of the four most common species of hammerhead sharks in the Southwestern Atlantic.

Triiodothyronine (T3) action on aquatic locomotor behavior during metamorphosis of the bullfrog Rana catesbeiana.

Thyroid hormones--particularly triiodothyronine, T3--play a critical role in the morphological transformations comprising metamorphosis in larval bullfrogs (Rana catesbeiana). Traditional staging criteria for anuran larvae incompletely distinguish physiological and behavioral changes during growth. We therefore first developed a new parameter to describe larval growth, the developmental index (DI), which is simply the ratio between the tail length of the larva and its head diameter. Using the DI we were able to identify two distinct populations classifying the larvae during growth along a continuous linear scale with a cutoff value of DI at 2.8. Classification based on the DI, used in this study, proved an effective complement to existing classifications based on developmental staging into pre- or pro-metamorphic stages. Exposure to T3 in the water induced a rapid (beginning within 5 min) and significant decrease (approximately 20-40%) in locomotor activity, measured as total distance traversed and velocity. The largest decrease occurred in more developed larvae (DI<2.8). To determine correlated changes in the neuromuscular junctions during metamorphosis and apoptotic tail loss, miniature endplate currents from tail muscle were recorded during acute exposure to a hypertonic solution, which simulates an apoptotic volume decrease. Our results support a role for T3 in regulating larval locomotor activity during development, and suggest an enhanced response to volume depletion at the neuromuscular junction of older larvae (DI<2.8) compared to younger animals (DI> or =2.8). We discuss the significance of the possible role of an apoptotic volume decrease at the level of the neuromuscular junction.

Longitudinal and radial gradients of PO(2) in the hamster cheek pouch microcirculation.

OBJECTIVES: The aim of this study was to determine longitudinal and radial gradients in oxygen tension (PO(2)) in microvessels of the hamster cheek pouch. METHODS: We measured PO(2) using the phosphorescence-quenching method in two orders of arterioles (45.8 +/- 5.5 and 19.9 +/- 1.8 micro m diameter), capillaries, and two orders of venules (50.5 +/- 3.4 and 21.4 +/- 2.0 micro m diameter) in order to determine the longitudinal PO(2) gradient. At the arteriolar and venular sites, we also measured PO(2) at four different sites for an analysis of radial PO(2) gradients: centerline, inside wall (larger arteriole and venule only), outside wall, and interstitium. We used 10 hamsters weighing 115 +/- 27 g anesthetized with pentobarbital intraperitoneally and maintained with alpha-chloralose intravenously. The cheek pouch was everted and a single-layered preparation was studied by intravital microscopy. Albumin-bound Pd-porphyrin was infused into the circulation and excited by flash illumination at 10 Hz, with a rectangular diaphragm limiting the excitation field to 5 x 25 micro m. RESULTS: In the longitudinal direction, intravascular PO(2) decreased significantly (P < 0.01) from large arterioles (39.5 +/- 2.3 mmHg) to small arterioles (32.2 +/- 0.3 mmHg), then to capillaries (30.2 +/- 1.8 mmHg), and on to small venules (27.3 +/- 2.1 mmHg) and large venules (25.5 +/- 2.2 mmHg). In the radial direction, PO(2) decreased significantly (P < 0.01) in and around larger arterioles, and to a lesser extent, around the smaller ones (P < 0.05). There was no significant PO(2) gradient, longitudinal or radial, associated with venules. The PO(2) difference from the centerline to the outside wall in large arterioles was 8.3 +/- 1.4 mmHg, and most of the decline in PO(2) in the radial direction was contributed by the intravascular difference (4.7 +/- 2.1 mmHg) and only about 1.0 +/- 2.7 mmHg by the transmural difference. CONCLUSIONS: Our data show that there are large intra-arteriolar radial PO(2) gradients, but no large transmural PO(2) differences, suggesting that the oxygen consumption of the microvessel wall is not exceptionally high.

Sistema estomatognático e postura corporal na criança com alterações sensório-motoras / Stomatognathic system and body posture in children with sensoriomotor deficits

TEMA: a literatura aponta a postura corporal como um aspecto importante no tratamento de crianças com alterações sensório-motoras. No caso do paralítico cerebral, os reflexos apresentam-se mais intensos do que as reações de retificação e de equilíbrio, inibindo-as, provocando assim um atraso ou impedimento do controle cervical, de tronco e de quadril, que se reflete no Sistema Estomatognático; OBJETIVO: verificar a relação entre a postura corporal e a adequação do Sistema Estomatognático nessa população, quanto à postura e funcionalidade e sua efetividade no processo terapêutico fonoaudiológico; MÉTODO: foram realizadas avaliação inicial, intervenção fonoaudiológica e reavaliação em dezessete crianças com alterações sensório-motoras, com idades entre um ano e seis anos e três meses. A intervenção terapêutica foi realizada durante dez meses, com sessões semanais individuais, sempre com a presença do cuidador. Todas as sessões foram transcritas em protocolo específico e a avaliação e a reavaliação foram gravadas em videoteipe; RESULTADOS: observamos melhora estatisticamente significante dos aspectos do sistema estomatognático em 100 por cento das crianças, tanto nas estruturas isoladamente, quanto em conjunto. O mesmo foi observado com relação às funções; CONCLUSAO: a adequação da postura corporal das crianças estudadas favoreceu de forma significativa o desenvolvimento e adequação do sistema estomatognático quanto à postura e a funcionalidade.

[Stomatognathic system and body posture in children with sensoriomotor deficits]. / Sistema estomatognático e postura corporal na criança com alterações sensório-motoras.

BACKGROUND: Literature points that body posture is an important aspect in the treatment of children with sensorimotor deficits. Considering individuals with cerebral palsy, reflexes are often more intense than reactions of rectification and equilibrium, causing, therefore, a delay or obstacle in cervical, torso and hip control. This delay has as a consequence an impact on the Stomatognathic System. AIM: To verify the relation between body posture and the Stomatognathic System in this population, regarding posture and function, and its effectiveness in the process of speech-language intervention. METHOD: 17 children with sensorimotor deficits, aged between 1 and 6:3 years, were submitted to an initial assessment, followed by speech-language intervention and re-assessment. Speech-language intervention occurred for a period of 10 months, with weekly individual sessions, always in the presence of the caretaker. All sessions were transcribed in a specific protocol and the assessment and re-assessment sessions were videotaped. RESULTS: A statistically significant improvement of stomatognathic system in 100% of the children was observed, not only of the isolated structures, but also of the whole system. The same was observed for the assessed functions. CONCLUSION: The improvement of body posture of the studied children favored significantly the development and improvement of the stomatognathic system regarding the aspects of posture and function.

Feeding mechanisms in two treefrogs, Hyla nana and Scinax nasicus (Anura: Hylidae).

After the description of the chondrocranium, hyobranchial apparatus, associated musculature, buccal apparatus, buccopharyngeal cavity, digestive tract, and gut contents, it was possible to define the feeding modes of Scinax nasicus and Hyla nana tadpoles (Gosner Stages 31-36). Scinax nasicus larvae are "typical" microphagous tadpoles, with keratodonts and robust rostrodonts appropriate for rasping surfaces and mincing of food particles; the buccopharyngeal cavity is equipped with filtering structures and has a conspicuous glandular zone and a highly developed branchial basket. In contrast, H. nana tadpoles have a modified buccal apparatus; the reduction of the buccopharyngeal and branchial basket structures, together with the high lever-arm ratio and the great development of the depressor muscles of the buccal floor are indicative of macrophagous feeding.

ACh-induced endothelial NO synthase translocation, NO release and vasodilatation in the hamster microcirculation in vivo.

Studies in cultured cells show that activation of endothelial nitric oxide (NO) synthase (eNOS) requires the dissociation of this enzyme from its inhibitory association with caveolin-1 (Cav-1), and perhaps its translocation from plasma membrane caveolae to other cellular compartments. We investigated the hypothesis that in vivo NO-dependent vasodilatation is associated with the translocation of eNOS from the cell membrane. To this end, we applied ACh topically (10-100 microM for 10 min) to the hamster cheek pouch microcirculation and measured NO production, blood flow and vessel diameter, and assessed subcellular eNOS distribution by Western blotting. Baseline NO production was 54.4 +/- 5.2 pmol min(-1) (n = 16). ACh increased NO release, caused arteriolar and venular dilatation and elevated microvascular flow. These responses were inhibited by N(G)-nitro-L-arginine (30 microM). The maximal increase in NO production induced by 10 microM and 100 microM ACh was 45 +/- 20 % and 111 +/- 33 %, respectively; the corresponding blood flow increases were 50 +/- 10 % and 130 +/- 24 %, respectively (n = 4-6). Both responses followed a similar time course, although increases in NO preceded flow changes. In non-stimulated tissues, eNOS was distributed mainly in the microsomal fraction. ACh-induced vasodilatation was associated with eNOS translocation to the cytosolic and Golgi-enriched fractions. After 1.5, 3.0 or 6.0 min of application, 10 microM ACh decreased the level of membrane-bound eNOS by -13 +/- 4 %, -60 +/- 4 % and -19 +/- 17 %, respectively; at the same time points, 100 microM ACh reduced microsomal eNOS content by -38 +/- 9 %, -61 +/- 16 % and -40 +/- 18 %, respectively (n = 4-5). In all cases, microsomal Cav-1 content did not change. The close ACh concentration dependence and the concomitance between eNOS subcellular redistribution and NO release support the concept that eNOS translocation from the plasma membrane is part of an activation mechanism that induces NO-dependent vasodilatation in vivo.

Renal and extrarenal congenital rhabdoid tumor: diagnosis by fine-needle aspiration biopsy and FISH.

We report on 2 patients with congenital malignant rhabdoid tumor, one located to the kidney and the other to the soft parts of the cheek. Initial diagnosis was performed through percutaneous fine-needle aspiration biopsies, which yielded cytologic smears exhibiting highly characteristic rhabdoid cells, i.e., cells with a large, vesicular nucleus with a prominent nucleolus and cytoplasm exhibiting a large, dense, paranuclear inclusion. Interphase FISH demonstrated only one signal (heterozygous deletion) for the BCR gene in both cases, supporting the diagnosis. Surgical pathology and immunohistochemistry of both cases confirmed the diagnosis. Both patients died within the following 6 mo to 1 yr.