Efeito do extrato aquoso de cabelo de milho (Zea mays L. ) sobre a excreção renal de água e eletrólitos e pressão arterial em ratos Wistar anestesiados / Effect of aqueous extract of corn silks (Zea mays L. ) on the renal excretion of water and electrolytes and arterial pressure in anesthetized Wistar rats

O milho (Zea mays L.) possui nos estigmas (cabelo de milho) substâncias que o tornam diurético, podendo ser importante no controle da hipertensão. No presente estudo, foi investigado o efeito do extrato aquoso (EA) do cabelo de milho sobre o fluxo renal de água (V) e eletrólitos e a pressão arterial (PA) em ratos Wistar anestesiados. Foram realizados 3 grupos: I) Controle - administração intragástrica (AI) de 1mL de água destilada; II) AI de 1 mL de EA de cabelo de milho a 20 por cento e III) AI de 1 mL de solução contendo furosemida. Canulou-se a artéria carótida esquerda para mensuração da PA, de 10 em 10 minutos, e a bexiga urinária, para mensuração de V de 30 em 30 minutos e da carga excretada dos íons sódio (Qe (Na+)) e potássio (Qe (K+)). Protocolo experimental: quatro períodos de 30 minutos cada: basal (avaliação dos parâmetros basais) e experimentais (Ex) 1, 2 e 3 (30, 60 e 90 minutos após a AI, respectivamente). O Grupo I não apresentou alterações significativas entre os períodos nos parâmetros analisados (p>0,05). O Grupo II apresentou aumento significativo (p<0,05) em V, em Qe (Na+) e em Qe (K+) nos períodos Ex2 e Ex3, com redução significativa na PA (p<0,05) em Ex2 e Ex3. Conforme esperado, o Grupo III apresentou aumento significativo em V nos períodos Ex2 (p<0,05) e Ex3 (p<0,001), aumento em Qe (Na+) em Ex1 (p<0,05), Ex2 (p<0,001) e Ex3 (p<0,001) e aumento em Qe (K+) em Ex2 (p<0,05) e Ex3 (p<0,001), com redução significativa na PA (p<0,05) em Ex2 e Ex3. Os dados mostram que o EA do cabelo de milho possui efeito diurético, porém não age como um diurético "de alça", uma vez que não levou à expoliação de potássio e nem a uma excreção tão acentuada de sódio quanto à furosemida.

The corn (Z. mays) has in its stigmas (corn silks) substances that make it diuretic, which may be important in hypertension control. In this study, the effect of aqueous extract (AE) of corn silks on the renal flow of water (V) and electrolytes and arterial pressure (AP) was investigated in anesthetized Wistar rats. Three groups were tested: I) Control - intragastric administration (IA) of 1mL of distilled water, II) IA of 1 mL of AE of corn silks at 20 percent and III) IA of 1 mL of a solution containing furosemide. Cannulation was performed in the left carotid artery to measure AP, at every 10 minutes, and in the urinary bladder to measure V, at every 30 minutes, and the excreted load of ions sodium (Qe (Na+)) and potassium (Qe (K+)). Experimental protocol: four periods of 30 minutes each: basal (evaluation of basal parameters) and experimental (Ex) 1, 2 and 3 (30, 60 and 90 minutes after IA, respectively). Group I had no significant differences between periods for the analyzed parameters (p>0.05). Group II presented a significant increase (p<0.05) in V, Qe (Na+) and Qe (K+) in periods Ex2 and Ex3, with significant reduction in AP (p<0.05) in Ex2 and Ex3. As expected, Group III had a significant increase in V in periods Ex2 (p<0.05) and Ex3 (p<0.001), an increase in Qe (Na+) in Ex1 (p<0.05), Ex2 (p<0.001) and Ex3 (p<0.001) and an increase in Qe (K+) in Ex2 (p<0.05) and Ex3 (p<0.001), with an important reduction in AP (p<0.05) in Ex2 and Ex3. These data show that AE of corn silks has a diuretic effect but does not act as a loop diuretic since it did not lead to potassium loss or marked sodium loss, compared to furosemide.

Hidroxietilalmidón (Hextend®) en solución electrolítica balanceada en el choque hipovolémico hemorrágico / Use of hetastarch in a balanced electrolyte solution - Hextend®- in the resuscitation of the patient in hypovolemic hemmorrhagic shock: review of the international literature

Hextend® is a preparation of hetilstarch in a balanced electrolyte solution that contains 143 mEq/L of sodium, 124mEq/L of chloride, 5 mEq/L of calcium 3 mEq/L of potassium 0.9 mEq/L of magnesium, 0.99 g/L of glucose and 24 mEq/L of lactate. It has a volume of distribution similar to blood volume which enables it to stay in the intravascular compartment until it is renally cleared or absorbed by the reticuloendothelial system. It shows a bimodal pattern of clearance with a half life during the first 8 hrs of its infusion of 4.2 hrs and during the 7 days following of 38.2 hrs. Hextend® is currently one of the preferred resuscitation solutions in the hypovolemic patient showing a better profile of effects over hemostasis and acid base status and conferring a better survival over similar patients resuscitated with crystalloids or other synthetic colloids. Hextend® provides an adequate fluid that is effective in the resuscitation of the trauma patient in hypovolemic hemorrhagic shock and promises to become the fluid of choice in the routine management of these patients. There is a need of more randomized prospective studies in the field of trauma using Hextend ® and its combination with the inflammatory cascade modifiers such as ethyl pyruvate among others.

Hextend® es una combinación de hetilalmidón balanceada en una solución de electrolitos que contiene 143 mEq/L de sodio, 124 mEq/L de cloro, 5 mEq/L de calcio, 3 mEq/L de potasio, 0,9 mEq/L de magnesio, 0,99 g/L de glucosa y 24 mEq/L de lactato. Posee un volumen de distribución equivalente al volumen sanguíneo manteniéndose en el compartimento vascular hasta ser excretado vía renal o absorbido por el sistema retículo-endotelial. Estas características le confieren un patrón farmacocinético bimodal con una vida media de 4,2 horas durante las primeras 8 hrs de infusión y de 38,2 h durante los primeros 7 días. Hextend® es actualmente una de las soluciones de reanimación con mejor perfil de efectos sobre la hemostasia y el equilibrio ácido base del paciente en choque hipovolémico y confiere un aumento de la sobrevida, comparado con controles resucitados con cristaloides u otros coloides sintéticos. Esta combinación de hetilalmidón en una solución amortiguadora electrolítica posee mínimos efectos sobre la función hemostática y plaquetaria por lo que actualmente es preferido frente a soluciones cristaloides y otros coloides utilizados en el pasado en la reanimación de pacientes politraumatizados en estado de choque hipovolémico hemorrágico. A su vez, promete transformarse en el fluido de elección en el manejo rutinario de estos pacientes. En relación al uso de este producto es imperativo realizar un mayor número de estudios prospectivos randomizados. La literatura internacional augura un esplendoroso futuro al uso de Hextend®, como también a su posible combinación con modificadores de la cascada inflamatoria, entre otros con el etil piruvato.

Effects of electrolyte viscosity on the efficiency of the electrochemical removal of lead ions using porous flow-through electrodes

The current study addresses the effect of the electrolyte viscosity on the efficiency of porous flow-through electrode [PFTE] made up of stacked screens during the electrochemical removal of lead ions from flowing alkaline solutions. Two types of efficiencies characterize the overall behaviour of the PFTE, namely, the collection efficiency [ratio of the captured ions to the feed concentration] and the coulombic efficiency [percentage of the total current used for the electrodeposition of lead ions]. The increase in the electrolyte viscosity causes a decrease in the experimentally measured limiting current of the electrodeposition reaction at the same electrolyte flow rate, and hence the collection efficiency decreases correspondingly. Also, the coulombic efficiency decreases with the increase of the electrolyte viscosity. This is attributed to the consequences of decreasing the diffusivity and the interfacial mass transfer coefficient of lead ions with the increase of electrolyte viscosity. On the other hand, the conductivity of the electrolyte has no effect on the limiting current

Double logarithmic, linear relationship between postmortem vitreous sodium/potassium electrolytes concentration ratio and time since death in subjects of Chandigarh zone of Northwest India.

Present authors had recently demonstrated a highly significant double logarithmic linear relationship between time since death and serum sodium/potassium concentration ratio and also with the serum chloride concentration in humans. Consecutively the present study was carried out to substantiate this disposition in vitreous humour. The data on postmortem vitreous sodium/potassium electrolytes concentration ratio in 1026 subjects, revealed a highly significant relationship between logarithm of vitreous sodium/potassium electrolytes concentration ratio and logarithm of time since death upto 66 hrs. of death. Postmortem interval can be predicted from vitreous sodium/potassium electrolytes concentration ratio with standard error of estimate 0.1800 hrs. However, factors like environmental temperature, age & gender also influences it significantly.

Electrolitos en materia fecal en niños con enfermedad diarreica

Se realizó un estudio prospectivo en el servicio de pediatría del Hospital de la Victoria en el que se consideraron las siguientes variables en 44 pacientes con enfermedad diarreica: sexo, edad, características clínicas de la enfermedad diarreica, medición del pH, electrólitos en materia fecal y azúcares reductores, las cuales se consideran fundamentales para poder hacer dignóstico etiológico de la diarrea y su respectivo tratamiento

Effect of KCl and CsCl electrolytes on the kinetics of reaction between bromopropionate and thiosulphate ions

The primary salt effect on reaction between beta- bromo - propionate and thiosulphate ions has been studied in presence of various concentrations of potassium chloride and ceasium chloride at different temperatures. The effects of ionic strength on rate constants are very specific and dependent upon the ionic and the concentration of the cation of the added salt. The rate constants have been found to decrease with increasing concentrations of inert salts. The activation parameters such as energy of activation [E[a]] change in entropy of activation [delta S[++]],change in free energy of activation [delta G[++]] and temperature coefficients of the rate constants in the presence of potassium chloride and ceasium chloride have been evaluated as a function of ionic strength

Electrokinetic studies on interfaces of group IV-a metal oxides in different electrolytes

Experiments were conducted to study the effect of constant concentrations [2.0 mmol] of Sr2+, Ba2+, Mg2+, Ni2+, Mn2+, or Fe3+ ions on the electrokinetic [sigma] potentials of SiO2, GeO2, SnO2 and PbO2 oxides over a wide range of pH. The chlorides of these cations, except Fe3+ decreased the negative electrokinetic potential of the above oxides by 10-15 mv, the effect was more pronounced at pH > 5.0. However, Sr2+ and Ba2+ ions present in all oxides as well as Ni2+, CO2+, and Mn2+ in GeO2 oxides showed no effect on the point of zero charge [PZC] of these oxides, but the presence of Fe3+ ions shifted the PZC values of oxides at pH values from 2.0 +/- 0.25 to 6.7 +/- 0.1, while Ni2+, CO2+ and Mn2+ in GeO2 oxides showed a new PZG at pH = 8.15 +/- 0.35. Furthermore, the effect of Mg2+ ions in SiO2, SnO2 and PbO2 suspensions was sharply different from the other alkaline-earth ions, the sign of the sigma potential was reversed to positive at pH >10.5. The adsorption mechanism of the specific metal ion species on the oxide surfaces is discussed

El concepto actual del sistema renina-angiotensina / Current concept of the renin-angiotensin system

El concepto tradicional del sistema renina-angiotensina (SRA) es el de un sistema andocrino que juega un papel central en el balance de agua y electrólitos y en la homeostasis de la presión arterial. El angiotensinógeno y la renina, secretados por el hígado y el riñón, respectivamente, interactúan para formar angiotensina l, la cual, a su vez, es hidrolizada por la enzima convertidora de angiotensina l para formar el péptido biológicamente activo del sistema, angiotensina II. Debido a que esta última enzima se localizó primero en la vasculatura pulmonar, se pensó que la angiotensina II se producía sólo en ese sitio y que posteriormente llegaba a sus órganos blanco por medio de la circulación. Sin embargo, gracia al desarrollo de nuevas técnicas bioquímicas y de biología molecular se ha podido documentar la presencia de los componentes del SRA, incluyendo sus ácidos ribonucleicos mensajeros (ARNm), en múltiples tejidos como riñón, vasos sanguíneos, corazón, cerebro y glándulas adrenales, entre otros. La presencia de los ARNm sugiere fuertemente que las proteínas del SRA se sintetizan localmente. Esto ha llevado a proponer que el SRA puede tener funciones paracrinas, autocrinas, e incluso intracrinas, además de las endocrinas ya bien conocidad, es decir, que el SRA puede estar involucrado en alguna función específica de cada tejido. Estos datos amplían el concepto tradicional del SRA ya que, además de su amplia distribución, se ha comprobado que solo SRA locales se regulan independientemente del sistema circulante. Por otra parte, estudiando el comportamiento de los SRA circulante y tisular ante diferentes situaciones patológicas como la hipertensión, se ha propuesto que la principal función del SRA circulante es mantener la homeostasis cardiorrenal a corto plazo, y que el control tónico de la resistencia vascular y de la función tisular local(por ejemplo, en adrenal y riñón) está reculada por los SRA locales. Finalmente, estas observaciones demuestran que el SRA tisular tiene un papel muy importante al igual que el SRA circulante.