Ontogenetic Development of Weberian Ossicles and Hearing Abilities in the African Bullhead Catfish

BACKGROUND: The weberian apparatus of otophysine fishes facilitates sound transmission from the swimbladder to the inner ear to increase hearing sensitivity. It has been of great interest to biologists since the 19(th) century. No studies, however, are available on the development of the weberian ossicles and its effect on the development of hearing in catfishes. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the development of the weberian apparatus and auditory sensitivity in the catfish Lophiobagrus cyclurus. Specimens from 11.3 mm to 85.5 mm in standard length were studied. Morphology was assessed using sectioning, histology, and X-ray computed tomography, along with 3D reconstruction. Hearing thresholds were measured utilizing the auditory evoked potentials recording technique. Weberian ossicles and interossicular ligaments were fully developed in all stages investigated except in the smallest size group. In the smallest catfish, the intercalarium and the interossicular ligaments were still missing and the tripus was not yet fully developed. Smallest juveniles revealed lowest auditory sensitivity and were unable to detect frequencies higher than 2 or 3 kHz; sensitivity increased in larger specimens by up to 40 dB, and frequency detection up to 6 kHz. In the size groups capable of perceiving frequencies up to 6 kHz, larger individuals had better hearing abilities at low frequencies (0.05-2 kHz), whereas smaller individuals showed better hearing at the highest frequencies (4-6 kHz). CONCLUSIONS/SIGNIFICANCE: Our data indicate that the ability of otophysine fish to detect sounds at low levels and high frequencies largely depends on the development of the weberian apparatus. A significant increase in auditory sensitivity was observed as soon as all weberian ossicles and interossicular ligaments are present and the chain for transmitting sounds from the swimbladder to the inner ear is complete. This contrasts with findings in another otophysine, the zebrafish, where no threshold changes have been observed

Вплив водно-електролітного обміну на функціональний стан нирок у здорових вагітних та при гестозі

The authors have examined 60 gravidas with gestosis and 7 – with physiological pregnancy of the IInd half of the pregnancy of the age within the range of 18-29 years with a research of the electrolyte, hormonal indices of gravidas in the plasma and erythrocytes in case of gestosis. Versidirectional changes both in the plasma and erythrocytes in gravidas with gestosis of different electrolytes of the intra- and extracellular state have been revealed.Обследованы 60 беременных с гестозом и 7 – с физиологической беременностью II половины беременности возраста 18-29 лет с исследованием электролитных, гормональных показателей беременных при гестозе в плазме и эритроцитах. Найдены разнонаправленные изменения различных электролитов внутри- и внеклеточного содержания как в плазме, так и в эритроцитах у беременных с гестозом.Обстежено 60 вагітних із гестозом і 7 – з фізіологічною вагітністю ІІ половини вагітності віку 18-29 років із дослідженням електролітних, гормональних показників вагітних при гестозі у плазмі та еритроцитах. Виявлено різноспрямовані зміни як у плазмі, так і в еритроцитах у вагітних із гестозом різних електролітів внутрішньо- та позаклітинного стану

Corrida em piscina funda: limites e possibilidades para o alto desempenho Velocidad en piscina de profundidad: límites y posibilidades para un alto desempeño Deep water running: limits and possibilities for high performance

O objetivo deste estudo foi analisar os limites e possibilidades da utilização da corrida em piscina funda no treinamento de corredores de rendimento. Além disso, são discutidas as respostas agudas submáximas, máximas e crônicas, do ponto de vista fisiológico e biomecânico entre a corrida em terra e em piscina funda. As respostas máximas de freqüência cardíaca e consumo de oxigênio são menores no exercício aquático do que na corrida terrestre. Dados experimentais sugerem o uso do treinamento de corrida em piscina funda para corredores de rendimento; contudo, essas evidências são limitadas para treinamentos de até 10 semanas.<br>El objetivo de este estudio ha sido el de analizar los límites y posibilidades de la utilización de carreras de velocidad en piscina de profundidad durante el entrenamiento de velocista de rendimiento. Además de esto, son discutidas las respuestas agudas submáximas, máximas y crónicas, bajo el punto de vista fisiológico y biomecánico entre la carrera en tierra y en piscina profunda. Las respuestas máximas de frecuencia cardíaca y consumo de oxígeno son menores en el ejercicio acuático que en la de tierra. Datos experimentales sugieren el uso de entrenamiento de carrera en piscina profunda para velocistas de rendimiento, sin embargo estas evidencias son limitadas a entrenamientos de hasta 10 semanas.<br>The purpose of this study was to analyze the limits and possibilities of deep water running on training of performance runners. Besides, it has been discussed the submaximal acute, maximal acute and chronical responses, following physiological and biomechanical aspects between running on land and deep water running. Heart rate and oxygen uptake's maximal responses are lower in aquatic exercise than in running on land. Experimental evidences suggest the deep water running training for performance athletes, but these studies are limited in training program until ten weeks