The effect of salinity on osmoregulation and development of the juvenile fat snook, Centropomus parallelus (POEY).

Eurihaline fish support waters with different salt concentration. However, numerous studies have shown that salinity can affect fish development. Thus, the effect of salinity change from 20 to 5 and 35 on survival, weight, length, gill chloride cell ultrastructure and gill Na+, K+ ATPase activity was evaluated in Centropomus parallelus following short-term (6, 24 and 96 hours) and long-term exposure (30 and 60 days). Salinity did not affect C. parallelus survival, final weight and length. The quantity of chloride cells increased visibly at salinities of 5 and 35, with the cells exhibiting the typical features of uptake and secretory cells, respectively. Na+, K+ ATPase activity in the gill of the C. parallelus was significantly greater at a salinity of 5 than at a salinity of 20 or 35 after 96 hours, but not after 30 or 60 days. These results indicate that salinity change from high to low salt water induces gill chloride cell and Na+, K+ ATPase activity adaptations after short-term exposure. However, after long-term exposure at salinity 5, gill Na+, K+ ATPase activity is no more necessary at high levels. The increase in salinity to 35 does not induce significant change in gills. Juveniles of C. parallelus may thus be capable of acclimating to salinities of 5 to 35 for 60 days without significant effects on development.

The effect of salinity on osmoregulation and development of the juvenile fat snook, Centropomus parallelus (POEY) / O efeito da salinidade sobre a osmoregulacao e o desenvolvimento do juvenil de robalo-peva, Centropomus parallelus (POEY)

Eurihaline fish support waters with different salt concentration. However, numerous studies have shown that salinity can affect fish development. Thus, the effect of salinity change from 20 to 5 and 35 on survival, weight, length, gill chloride cell ultrastructure and gill Na+, K+ ATPase activity was evaluated in Centropomus parallelus following short-term (6, 24 and 96 hours) and long-term exposure (30 and 60 days). Salinity did not affect C. parallelus survival, final weight and length. The quantity of chloride cells increased visibly at salinities of 5 and 35, with the cells exhibiting the typical features of uptake and secretory cells, respectively. Na+, K+ ATPase activity in the gill of the C. parallelus was significantly greater at a salinity of 5 than at a salinity of 20 or 35 after 96 hours, but not after 30 or 60 days. These results indicate that salinity change from high to low salt water induces gill chloride cell and Na+, K+ ATPase activity adaptations after short-term exposure. However, after long-term exposure at salinity 5, gill Na+, K+ ATPase activity is no more necessary at high levels. The increase in salinity to 35 does not induce significant change in gills. Juveniles of C. parallelus may thus be capable of acclimating to salinities of 5 to 35 for 60 days without significant effects on development.

Peixes eurihalinos suportam águas com diferentes concentrações de sal. Contudo, muitos estudos têm mostrado que a salinidade pode afetar o desenvolvimento do peixe. Portanto, o efeito da mudança de salinidade de 20 para 5 e 35 na taxa de sobrevivência, peso, comprimento, morfologia das células de cloreto branquiais e atividade da Na+, K+ ATPase foram avaliadas no Centropomus parallelus após curto (6, 24 e 96 horas) e longo tempo de exposição (30 e 60 dias). A salinidade não afetou a sobrevivência, o peso e comprimento final do robalo-peva. A quantidade de células de cloreto aumentou visivelmente nas salinidades 5 e 35, exibindo morfologias típicas de células que absorvem e secretam sal, respectivamente. A atividade da Na+, K+ ATPase nas brânquias do C. parallelus foi significativamente maior na salinidade 5 do que nas salinidades 20 ou 35 após 96 horas, mas não após 30 e 60 dias. Esses resultados indicam que a mudança de alta para baixa salinidade provoca adaptações nas células de cloreto e na atividade da Na+, K+ ATPase branquial em curto prazo. Contudo, após longa exposição na salinidade 5, a alta atividade da Na+, K+ ATPase branquial não é mais necessária. O aumento de salinidade para 35 não induz mudanças significativas nas brânquias. Portanto, juvenis de C. parallelus possuem a capacidade de aclimatação nas salinidades de 5 a 35 semefeitos significativos no desenvolvimento após 60 dias.

Surface ultrastructure of the gills of the mullets Mugil curema, M. liza and M. platanus (Mugilidae, Pisces).

Mugil curema, M. liza, and M. platanus were collected from the southeastern and southern coast of Brazil. The second gill arches were analyzed by scanning electron microscopy and histology. The highest density of chloride and mucus-secreting cells was observed in the gill filaments of M. liza and M. platanus. Spines are scarce and were found only in the pharyngeal region of M. curema. The dorsal angle of curvature of the simple projections is most reduced in the rakers of M. liza and M. platanus. The raker borderline on the internal side of the arches of M. curema has grooves that do not occur in the other two species. On the external side of the branchial arches, the borders of the rakers of M. liza and M. platanus are smooth. The shape of the rakers is characteristic for each species: in M. curema, it resembles the letter "D"; in M. liza, it is trapezoidal, and in M. platanus, it is triangular. Thus there is a morphologic similarity between M. liza and M. platanus, and both differ from M. curema. All three species show elongated and extremely elaborated rakers that are placed next to each other and turned toward the opercular cavity. There are few taste buds and only several mucus-secreting cells along the whole pharyngeal region. These characteristics suggest that these species do not select food chemically but obtain it mechanically with the rakers and aggregate it with mucus.

Lethal effects of inorganic mercury on cells and tissues of Trichomycterus brasiliensis (Pisces; Siluroidei).

The uptake of heavy metals like mercury is rapid and tissue and cell pathologies are a consequence of its concentration in water and the time of exposure. For Trichomycterus brasiliensis, inorganic mercury is lethal above 0.1 mg.l(-1) in 24 hours. The gills were severely affected: an increased cell proliferation in the interlamellar regions leads to a thickening of the secondary lamellae. The lamellar fusion is higher 12 hours after exposure. The liver is increasingly damaged: after 4 hours the hepatocytes show hyaline sites around the nuclei proliferation of smooth ER, modified mitochondria and less electron dense nuclei without nucleolus. After 24 hours, necrosis is almost complete and blood comes out of all capillaries. The kidneys are also disorganized and tubule cells decrease in number and change in size, but there is a tendency of tissue recovery after 24 hours. Nerves such as the optic, show disorganized disposition of axons and mainly disruption and dissociation of myelin sheaths, leading to a decrease in motility and coordination. All these results demonstrate that T. brasiliensis is severely affected by inorganic mercury in concentrations that are sublethal for many other species.

Decidir el destino del prepucio. / Deciding the destination of the prepuce

El destino normal del prepucio es a la retractilidad facil y completa que en general ocurre antes de los 5 anos y es la norma en la adolescencia. Hay sin embargo, un porcentaje no determinado de ninos en los que el prepucio no sigue esta evolucion natural:en este grupo estan las fimosis verdadera,con cicatrizacion del prepucio y las adherencias balano prepuciales, que en distinto grado van a evitar la retractilidad prepucial. Para corregir estos problemas se han planteado diversas soluciones: La circuncision neonatal de rutina esta descartada por la mayoria de los especialistas en la actualidad. La circuncision terapeutica tiene riesgos frecuentes y a veces graves por lo que esta indicada solo en casos de fimosis, balano postitis recurrente, parafimosis, irreductible y otros casos raros. La debridacion balano postal es una alterantiva terapeutica para corregir las adherencias y facilitar el aseo que merece ser estudiada. Mayores estudios son necesarios para definir precozmente las poblaciones que vayan a evolucion medica de uno y otro tipo

[Treatment of typhoid fever with chloramphenicol or ampicillin combined with oxyphenbutazone]. / Tratamiento de las fiebres tíficas con cloranfenicol o ampicilina asociados a oxifenbutazona.

Ninety-four patients with typhoid fever were treated, at random, with three therapeutic regimens: chloramphenicol alone, chloramphenicol plus oxyphenbutazone, and ampicillin plus oxyphenbutazone. The results are evaluated analyzing the body temperature graph and by serial blood had bone marrow cultures taken at intervals until they became negative. Bacteriologic diagnosis was confirmed by blood culture (39.3%) and/or bone marrow culture (77%). The mean duration of fever was 3.3 days for the group treated with chloramphenicol-oxyphenbutazone, 4.3 for those with chloramphenicol alone and 5 days for the group ampicillin-oxyphenbutazone; at the same time, blood cultures became negative at 4.4, 5.5 and 4.4 days respectively. Negativization of bone marrow cultures was not influenced by the addition of oxyphenbutazone. It is concluded that the influence of oxyphenbutazone in shortening the febrile period or in the negativization of blood cultures is not significant. It is considered that oxyphenbutazone is not an important therapeutic tool in this group of diseases.