Influence of environmental hypertonicity on the induction of ureogenesis and amino acid metabolism in air-breathing walking catfish (Clarias batrachus, Bloch).

Effect of environmental hypertonicity, due to exposure to 300 mM mannitol solution for 7 days, on the induction of ureogenesis and also on amino acid metabolism was studied in the air-breathing walking catfish, C. batrachus, which is already known to have the capacity to face the problem of osmolarity stress in addition to other environmental stresses in its natural habitats. Exposure to hypertonic mannitol solution led to reduction of ammonia excretion rate by about 2-fold with a concomitant increase of urea-N excretion rate by about 2-fold. This was accompanied by significant increase in the levels of both ammonia and urea in different tissues and also in plasma. Further, the environmental hypertonicity also led to significant accumulation of different non-essential free amino acids (FAAs) and to some extent the essential FAAs, thereby causing a total increase of non-essential FAA pool by 2-3-fold and essential FAA pool by 1.5-2.0-fold in most of the tissues studied including the plasma. The activities of three ornithine-urea cycle (OUC) enzymes such as carbamoyl phosphate synthetase, argininosuccinate synthetase and argininosuccinate lyase in liver and kidney tissues, and four key amino acid metabolism-related enzymes such as glutamine synthetase, glutamate dehydrogenase (reductive amination), alanine aminotransaminase and aspartate aminotransaminase were also significantly up-regulated in different tissues of the fish while exposing to hypertonic environment. Thus, more accumulation and excretion of urea-N observed during hypertonic exposure were probably associated with the induction of ureogenesis through the induced OUC, and the increase of amino acid pool was probably mainly associated with the up-regulation of amino acid synthesizing machineries in this catfish in hypertonic environment. These might have helped the walking catfish in defending the osmotic stress and to acclimatize better under hypertonic environment, which is very much uncommon among freshwater teleosts.

Histologic alterations of rat kidneys perfused with a Euro-Collins diltiazem solution / Alterações histológicas ocorridas em rins de ratos perfundidos com solução de Euro-Collins associada à diltiazem

PURPOSE: Analyse the histologic changes of rat kidneys perfused with isotonic saline solution (ISS), Euro-Collins solution (ECS) and Euro-Collins solution with diltiazem (ECSD). METHODS: Thirty-six Wistar rats were used divided equally, as follow: group A (ISS), group B (ECS) and group C (ECSD). Through a catheter placed into the abdominal aorta, a renal perfusion was performed using a solution according to the group to which the animal belonged. After the complete perfusion, bilateral nephrectomy was performed and the organs were preserved under hypothermia for five distinct periods of time. Glomerulus and tubule were evaluated through optical microscopy. RESULTS: Renal perfusion with ECS and ECSD proved effectiveness in the preservation of the organs up to 36 hours and an increase in the percentage of injured glomeruli was noticed only in the period of 48 hours. CONCLUSIONS: The results showed that exists an association between the tubular injury and the glomeruli lesion degree; kidneys with a higher degree of tubular damage were related to severe glomerular lesion. Also, the addition of a calcium channel blocker, diltiazem, to the ECS for the renal perfusion does not decrease the percentage of glomerular lesion.

OBJETIVO: Analisar as alterações histológicas nos rins de ratos perfundidos com solução salina isotônica (ISS), solução Euro-Collins (ECS) e solução Euro-Collins com diltiazem (ECSD). MÉTODOS: Foram divididos, de forma igual, 36 ratos Wistar, como se segue: grupo A (ISS), grupo B (ECS), grupo C (ECSD). Através de um cateter localizado na aorta abdominal, foi realizada a perfusão renal com a solução de acordo com o grupo ao qual o animal pertencia. Após a perfusão total, realizou-se nefrectomia bilateral com a preservação dos órgãos sob hipotermia por cinco períodos distintos de tempo. Glomérulos e túbulos foram avaliados por microscopia óptica. RESULTADOS: Tanto a perfusão renal com ECS quanto a com ECSD provaram sua efetividade na preservação dos órgãos em até 36 horas e aumento da porcentagem de glomérulos injuriados foi notada apenas no período de 48 horas. CONCLUSÕES: Os resultados mostraram haver uma correlação entre a injúria tubular e o grau de lesão glomerular; rins com um maior grau de dano tubular foram relacionados com lesão glomerular severa. Além disso, a adição de um bloqueador de canal de cálcio, diltiazem, à ECS para a perfusão renal não diminui a porcentagem de lesão glomerular.

Calcium channel blocker and renal mitochondrial function in warm renal ischemia

OBJECTIVE: Ions, particularly calcium ions, play an important role in ischemia-reperfusion cell injury. In this study, we investigated the action of verapamil on the mitochondrial function of kidneys submitted to ischemia without blood reperfusion in order to study isolated early and late ischemic effects. MATERIALS AND METHODS: 44 rats were submitted to bilateral warm renal ischemia for 30 minutes. The kidneys were then immediately reperfused with saline or Euro-Collins (EC) solution, with and without previous administration of 0.35 mg/kg of verapamil. Mitochondrial function was assessed at the end of renal perfusion and after 24 hours of cold preservation. RESULTS: In kidneys perfused with saline, verapamil allowed a significant early preservation of state III mitochondrial respiration, a result that was no longer evident after 24 hours. In kidneys perfused with EC solution, verapamil did not change state III for either early or late evaluations. Comparison of the groups showed that the results obtained for kidneys perfused with EC were always superior to those obtained for the saline group, except for the initial analysis of kidneys treated with saline and verapamil, which showed results similar to those obtained with EC perfusion alone. CONCLUSION: Administration of verapamil before warm ischemia provides partial and short-lasting functional protection of the mitochondrial function in kidneys perfused with sodium rich saline. With Euro-Collins solution, verapamil did not show any additional beneficial effect. This fact permits us to conclude that protective action is effective only under conditions that facilitate increased sodium uptake and/or potassium loss.

Efeitos renais e cardiovasculares da infusão de dopamina e da solução de cloreto de sódio a 7, 5 por cento: estudo experimental em cães com restrição hídrica / Renal and cardiovascular effects of dopamine and 7. 5 percent sodium chloride infusion: experimental study in dogs with water restriction

JUSTIFICATIVA E OBJETIVOS: É controvertido o uso da infusão de dopamina na proteção renal. O objetivo desta pesquisa foi estudar o efeito da dopamina, da solução hipertônica e da associação de ambas em cães com restrição hídrica, simulando o jejum pré-operatório. MÉTODO: Foram estudados, em 32 cães anestesiados com tiopental sódico e fentanil, os seguintes parâmetros da função renal: fluxo plasmático efetivo renal (depuração de para-aminohipurato de sódio), ritmo de filtração glomerular (depuração de creatinina) e as depurações de sódio, de potássio e osmolar, excreção fracionária de sódio e potássio, excreção de sódio e potássio e a resistência vascular renal. Os parâmetros cardiovasculares foram: pressão arterial média, freqüência cardíaca, pressão da veia cava inferior, índice cardíaco, hematócrito e índice de resistência vascular periférica. Os animais foram subdivididos, através de sorteio, em 4 grupos experimentais: Grupo 1 - G1 (n = 8) - grupo controle; Grupo 2 - G2 (n = 8) infusão de dopamina (2 'g.kg-1.min-1), Grupo 3 - G3 (n = 8) solução de cloreto de sódio a 7,5 por cento (2 ml.kg-1) e Grupo 4 - G4 (n = 8) - associação de dopamina (2 'g.kg-1.min-1) e cloreto de sódio a 7,5 por cento (2 ml.kg-1). Os grupos tiveram quatro fases experimentais e cada momento com duração de 30 minutos, compreendendo os momentos M1, M2, M3 e M4. RESULTADOS: O grupo da dopamina (G2) apresentou diminuição da pressão arterial média, da resistência vascular renal e da excreção de potássio. O grupo da solução hipertônica de cloreto de sódio (G3) apresentou aumento do índice cardíaco, do volume urinário, da depuração de sódio e de potássio, da excreção urinária de sódio e potássio e da excreção fracionária de sódio...

BACKGROUND AND OBJECTIVES: Dopamine infusion for renal protection is controversial. This study aimed at observing the effects of dopamine, hypertonic solution and the association of both in dogs with water restriction, emulating preoperative fast. METHODS: The following renal function parameters were studied in 32 dogs anesthetized with sodium pentobarbital and fentanyl: effective renal plasma flow (sodium para-aminohippurate clearance), glomerular filtration rate (creatinine clearance), sodium, potassium and osmolar clearance, sodium and potassium fractional excretion and renal vascular resistance. Cardiovascular parameters were: mean blood pressure, heart rate, inferior vena cava pressure, cardiac index, hematocrit and peripheral vascular resistance index. Animals were randomly distributed in four experimental groups: Group 1 - G1 (n = 8) - control group; Group 2 - G2 (n = 8) - dopamine infusion (2 µg.kg-1.min-1); Group 3 - G3 (n = 8) - 7.5% sodium chloride (2 ml.kg-1) and Group 4 - G4 (n = 8) - association of dopamine (2 µg.kg-1.min-1) and 7.5% sodium chloride (2 ml.kg-1). Groups underwent four experimental stages lasting 30 minutes each, and involving moments M1, M2, M3 and M4. RESULTS: Dopamine group (G2) had mean blood pressure, renal vascular resistance and potassium excretion decrease. Hypertonic sodium chloride group (G3) had cardiac index, urinary volume, sodium and potassium clearance, sodium and potassium urinary excretion and sodium fractional excretion increase...

JUSTIFICATIVA Y OBJETIVOS: Es controvertido el uso de la infusión de dopamina en la protección renal. El objetivo de esta pesquisa fue estudiar el efecto de la dopamina, de la solución hipertónica y de la asociación de ambas en canes con restricción hídrica, simulando el ayuno pre-operatorio. MÉTODO: Fueron estudiados, en 32 canes anestesiados con tiopental sódico y fentanil, los siguientes parámetros de la función renal: flujo plasmático efectivo renal (depuración de para-aminohipurato de sodio), ritmo de filtración glomerular (depuración de creatinina) y las depuraciones de sodio, de potasio y osmolar, excreción fraccionaria de sodio y potasio, excreción de sodio y potasio y la resistencia vascular renal. Los parámetros cardiovasculares fueron: presión arterial media, frecuencia cardíaca, presión de la vena cava inferior, índice cardíaco, hematócrito e índice de resistencia vascular periférica. Los animales fueron subdivididos, a través de sorteo, en 4 grupos experimentales: Grupo 1 - G1 (n = 8) - grupo control; Grupo 2 - G2 (n = 8) infusión de dopamina (2 µg.kg-1.min-1), Grupo 3 - G3 (n = 8) solución de clorato de sodio a 7,5% (2 ml.kg-1) y Grupo 4 - G4 (n = 8) - asociación de dopamina (2 µg.kg-1.min-1) y clorato de sodio a 7,5% (2 ml.kg-1). Los grupos tuvieron cuatro partes experimentales y cada momento con duración de 30 minutos, comprendiendo los momentos M1, M2, M3 y M4. RESULTADOS: El grupo de la dopamina (G2) presentó diminución de la presión arterial media, de la resistencia vascular renal y de la excreción de potasio. El grupo de la solución hipertónica de clorato de sodio (G3) presentó aumento del índice cardíaco, del volumen urinario, de la depuración de sodio y de potasio, de la excreción urinaria de sodio y potasio y de la excreción fraccionaria de sodio...

Na+i, K+i and Cl-i regulation of exocytosis in guinea-pig antral mucous cells

Effects of intracellular Na+, K+ and Cl- on Ca(2+)-regulated exocytosis activated by 10 microM acetylcholine (ACh) were studied in guinea-pig antral mucous cells which are permeabilized by nystatin treatment. Ca(2+)-regulated exocytotic events were modulated by [Na+]i, [K+]i and [Cl-]i via mediation of PTX-sensitive G proteins. Increases in [Na+]i and PTX inhibit G protein (G(Na)), which suppressed the exocytosis. Increases in [K+]i caused the exchange of G proteins (from G(Na) to G(K)) to increase, and GK evoked activation of the exocytosis and was inhibited by PTX. Increases in [Cl-]i and PTX inhibit G protein (G(Cl)), which stimulates exocytotic events. Based on these observations, the exocytosis in antral mucous cells were modulated by intracellular ions, concentration of which were increased or decreased by cell volume changes caused by Ach.

Soluciones salinas hipertónicas en neuroanestesia, ¿qué tanto sirven?

Por décadas, la administración de soluciones hipertónicas de diuréticos osmóticos, ha sido considerada como una de las pocas terapias disponibles para el tratamiento del edema cerebral y la hipertensión endocraneana. Aunque el manitol fue introducido por primera vez en la práctica clínica por Wise y Chater en 1962, es probablemente el agente más ampliamente usado para este propósito. Hay una amplia evidencia de que la administración de solución salina hipertónica puede producir efectos similares. La recuperación convencional de los pacientes en shock requiere gran cantidad de líquidos, lo cual puede llevar tanto a la formación de edema cerebral como a hipertensión endocraneana cerebral, ese incremento en la PIC luego de un traumatismo cerebral empeora el despertar neurológico. En numerosos estudios en animales, la resucitación del shock hemorrágico con soluciones hipertónicas e isotónicas en presencia o concomitantemente con daño cerebral, demuestra que las SSH minimizan el incremento en la PIC y disminuyen el agua cerebral, en la zona del cerebro que no tuvo lesión, durante la resucitación del sistema cardiovascular. Una gran preocupación expresada por algunos clínicos es la posibilidad de severa hipernatremia y posible daño neurológico, No hay reportes de mielinolisis central póntica o cualquier complicación neurolígica asociada con el uso de SSH en la resuscitación del shok, a pesar de infusiones muy rápidas en algunos estudios. Para finalizar, las SSH fueron tan efectivas como el Manitol en el tratamiento agudo de la hipertensión endocraneana. Por la habilidad de restaurar rápidamente el volumen plasmático, el uso de SSH puede ayudar a simplificar la resucitación de los pacientes con múltiples lesiones asociadas o no con daño cerebral. Pienso que necesitamos más evidencia clínica para incluirlas de manera rutinaria en nuestro protocolo

Efeito das soluçöes hipertônicas de sacarose em úlceras de córnea de coelho contaminada por Pseudomonas aeruginosa / Effect of hypertonic sucrose solutions on Pseudomonas aeruginosa infected corneal ulcers of rabbit eyes

Neste trabalho testa-se o uso de soluçöes hipertônicas de sacarose a 240 por cento e a 120 por cento em úlceras de córnea de coelho contaminadas por Pseudomonas aeruginosa. Os resultados desta pesquisa mostram que o uso de soluçöes hipertônicas de sacarose é ineficaz em úlceras de córnea infectadas pela bactéria acima. Por outro lado observou-se diminuiçäo da contagem bacteriana em úlceras de córnea contaminadas, submetidas a repetidas instilaçöes de soro fisiológico possivelmente por um efeito de limpeza mecânica do local da infecçäo

Disociación de la respuesta de alarma ante una mezcla de cristaloides y coloides en la inducción anestésica en cirugía cardíaca

El objetivo de la investigación fue probar si la administración de líquidos durante la inducción de la anestesia, al restaurar el déficit de agua y expandirel volumen intravascular, atenuaria la respuesta hormonal normalmente producida en cirugía. Se realizó un estudio randomizado controlado, en un centro de atención terciaria, en treinta y seis pacientes programados para cirugía electiva de bypass aorto-coronario. Los criterios- de exclusión fueron: función miocárdica severamente- reducida o disfunción renal conocida. Doce pacientes recibieron 10 ml/kg de solución Ringer (grupo baja dosis de cristaloide LDC), 12 pacientes recibieron 15 ml/kg solución Ringer (grupo alta dosis de cristaloide HDC), y 12 pacientes recibieron una combinación de 10 ml/kg de solución Ringer más 10 ml/kg1 de solución hidroxietil-starch (HES) 450.000 daltons, grado de substitución 0,7 (grupo C-HES), dentro de un período de 20 minutos posterior a la inducción de la anestesia (fentanyl, midazolam, pancuronio). El índice cardíaco y el índice sistólico se incrementaron en 20 por ciento y 15 por ciento en el grupo C-HES mientras de al ADH, la renina y la aldosterona disminuyeron (18 por ciento, 18 por ciento, 43 por ciento) respectivamente, luego de la administración de volumen. Luego de la administración de volumen, los niveles plasmáticos de lso sistemas hormonales llamados a responder ante la deshidratación e hipovolemia disminuyeron en el grupo C-HES. En los otros dos grupos no se presentó ninguna mejoría del estado hemodinámico y las hormonas medidas permanecieron en el mismo nivel observado durante la inducción de la anestesia. No hubo diferencias intergrupales en el volumen total administrado o en l balance hídrico al final de la cirugía. La administración de una combinación de soluciones cristaloides y coloides siguiendo la inducción de la anestesia en pacientes con función ventricular preservada, programados para cirugía cardíaca, conduce a atenuar las respuesta normal de los sistemas hormonales que se observa durante los estados de deshidratación e hipovolemia, en tanto que la restricción de líquidos promueve la actividad de dichos sistemas hormales

Transient increase in plasma catecholamines following hypertonic/hyperosmotic fluid administration in conscious rats

Plasma norepinephrine and epinephrine levels were monitored to determine possible alterations of the sympathetic nervous system caused by hypertonic fluid adeministration. Iv infusion (3.5 ml/Kg, 1 min) of 7.5% NaCl/6% Hespan transiently increased both plasma norepinephrine and epinehrine levels to 197 ñ 28% and 220 ñ 30% of control, respectively, at 1 min. These increases were no longer significant 5 or 15 min following infusion. A brief hypotension was also observed immediately following hypertonic fluid administration. This, prolonged sympathetic activation does not occur following hypertonic fluid infusion in normovolemic conscious rats

Recovery facilitation of malathion-intoxicated freshwater fish by exposure to hypertonic environment

The possibility of recovery in a hypertonic environment (10-40%NaCl) was investigated in the freshwater fish Oreochromis niloticus acutely intoxicated with the pesticide Malathion (40 ml/l. Survival was significantly higher in 15 g/l NaCl, with a shorter time required to reover posture and swimming, although 20% of revovered animals died on subsequent days.Exposure to a hypertonic environment plus pesticide did not protect the animals. Fish explosed to air until they became unresponsive recovered faster in freshwater than in a hupertnic environment. It os concluded that a hypertonic environmnet only facilitates recovery and that although osmotic mechanisms may explain the results, other possibilities reamin to be investigated

Hypertonic saline reverses bupivacaine-induced depression of rabbit Purkinje fiber depolarization Vmax

The present study describes the effect of a hypertonic increase in sodium chloride concentration on electrophysiological parameters. Membrane depolarization was recorded from rabbit Purkinje fibers superfused with warm, aerated Tyrode solution. An amount of 5% NaCl above that in normal Tyrode solution (HyNaCl, 344 mOsm) was added to the bathing medium for 30 min, significantly increasing the maximal rate of depolarization (Vmax + 15% vs - 7% for control), with minor effects on other parameters. When bupivacaine was superfused over the preparation for 30 min either in normal Tyrode or in HyNaCl, Vmax was significantly deveased (33% and 15%, respectively). HyNaCl protected the cardiac tissues from the depressive effect of 05micron/ml bupivacaine. We suggest that the infusion of hypertonic saline in intact animals may prove effective in preventing or reversing the cardiodepressant effect of bupivacaine

Soluciones cardioplejicas hipotérmicas en cirugía cardíaca: resultados comparativos con la de Saint Thomas / Hypothermic cardioplegic solutions in cardiac surgery: comparative results with the Saint Thomas' modified solution

Este estudio fue realizado para comparar los resultados y eficacia de dos soluciones cardiopléjicas diferentes. Un total de 182 pacientes fueron sometidos a cirugía de revascularización miocárdica, siguiendo similar técnica quirúrgica. En 40 pacientes usamos una solución con glucosa, potasio, CINa, CO2HNa y manitol. Cuarenta y dos pacientes recibieron la solución de Saint Thomas modificada por nosotros y conteniendo potasio, calcio, magnesio, CO2HNa, CINa y manitol. Consideramos los siguientes parámetros: 1) tiempo de recuperación miocárdica (I.R.M.); 2) uso de dopamina en la etapa final de la C.E.C. y 3) la necesidad de desfibrilación eléctrica. Con la solución cardiopléjica de Saint Thomas modificada, obtuvimos una reducción estadísticamente significativa de estos parámetros, para el T.R.M. y dopamina (p < 0,005) así como para la desfibrilación elétrica (p < 0,05). Concluimos que la solución de Saint Thomas modificada podría ser la solución de elección para asegurar una adecuada protección miocárdica

Evidence for the presence of osmoreceptors in medulla of the dog.

Hypertonic solutions of different substances were injected into the vertebral artery of dogs anesthetized with chloralose, preventing their access to the hypothalamic osmoreceptors by ligating the basilar artery and both the external carotid arteries. The hypertonic solution of sodium chloride produced graded inhibition of water diuresis and a concomitant rise in plasma antidiuretic hormone (ADH) level; hypertonic solution of glucose produced lesser effect. Hypertonic urea solution, on the other hand, did not alter the course of water diuresis. It was concluded that osmoreceptors are also present in the medulla which sense the changes in blood osmolarity and accordingly modify the ADH release.