Carta de control de Physella acuta usando tóxico de referencia. Intervalo de tolerancia comparado con el intervalo de confianza / Physella acuta control chart using reference toxicant. Tolerance interval vs confidence interval

Varias especies de organismos representativos de los diferentes ecosistemas son utilizados como biomodelos para evaluar el impacto ambiental de productos contaminantes del medio ambiente, así como de productos químicos y bioproductos que son empleados como fertilizantes y controladores de plagas en la agricultura. Se determinó la sensibilidad toxicológica cuantificada por la Concentración Letal Media (CL50) del biomodelo Physella acuta, expuesto al compuesto de referencia dicromato de potasio. Se partió de una concentración de 120 mg/L y se prepararon 7 diluciones decreciente (1:2) con cuatro réplicas y un grupo control sin tratamiento. Juveniles de Physella acuta fueron expuestos durante 96 h a las concentraciones del tóxico de referencia. El efecto cuantificado fue la mortalidad de los organismos. De un total de 20 estimaciones de la CL50 se obtuvo un valor promedio de 15,54 mg/L con una desviación estándar (S) de 5,92. Se determinó además, la precisión intralaboratorio del bioensayo con el tóxico de referencia mediante la estimación del coeficiente de variación (CV = 38,09 %). El intervalo de tolerancia superior e inferior de la CL50 al 95% de confianza fue de 27,38 mg/L y 3,37 mg/L, respectivamente. Se recomienda el uso del intervalo de tolerancia y no del intervalo de confianza para realizar la carta de control. Se concluye que es factible el uso del Physella acuta como biomodelo para ensayos ecotoxicológicos. (AU)

Several species of representative organisms of the different ecosystems are used as biomodels to evaluate the environmental impact of polluting products of the environment, as well as of chemical products and bioproducts that are used as fertilizers and pest controllers in agriculture. The toxicological sensitivity quantified by the Mean Lethal Concentration (LC50) of the Physella acuta biomodel, exposed to the reference compound Potassium Dichromate (K2Cr2O7), was determined. Seven serial concentrations (1:2) were evaluated with four replications and a control group without treatment. Juveniles of Physella acuta were exposed for 96 h to the concentrations of the reference toxicant. The quantified effect was the mortality of the organisms. From a total of 20 estimates of the LC50, an average value of 15.54 mg/L was obtained with a standard deviation (S) of 5,92. Furthermore, the intralaboratory precision of the bioassay with the reference toxicant was determined by estimating the coefficient of variation (CV = 38,09%). The upper and lower tolerance interval of the LC50 at 95% confidence was 27,38 mg/L and 3,37 mg/L, respectively. The use of the tolerance interval and not the confidence interval is recommended to make the control chart. It is concluded that the use of Physella acuta as a biomodel for ecotoxicological tests is feasible. (AU)

Bioensayo de toxicidad aguda en tres biomodelos utilizando compuestos de referencia / Acute toxicity bioassay in three biomodels using reference compounds

Los bioensayos son herramientas ampliamente utilizadas en el campo de la ecotoxicología. Como cualquier instrumento analítico, requieren ser calibrados frente a un patrón, con fines de control de calidad analítica de los organismos a utilizar en estas pruebas. Para dar cumplimiento a esta premisa se procedió a la evaluación de la toxicidad aguda de dos tóxicos de referencia en tres biomodelos representativos del ecosistema: Artemia sp., Physa cubensis y semillas de Lactuca sativa. Para determinar la toxicidad sobre los biomodelos se emplearon dos patrones: dicromato de potasio y sulfato de cobre. En ambos casos se preparó una solución madre y a partir de ella se realizaron diluciones seriadas, estableciéndose 3 réplicas por tratamiento. Para el control negativo se utilizó agua según las condiciones del hábitat de cada especie. El estudio fue realizado a temperatura y humedad controladas. Se observó para cada experimento la mortalidad como variable principal y se calculó la concentración letal media (CL50). Se apreció un decrecimiento de la mortalidad a medida que disminuyó la concentración de cada tóxico empleado. Se concluyó que el dicromato de potasio y el sulfato de cobre se pueden utilizar como patrones en la calibración de ensayos ecotoxicológicos de los biomodelos empleados

Similar to any analytical instrument, bioassays used in the field of ecotoxicology should be calibrated against a standard for analytical quality control purposes of the test organisms. To this end, the acute toxicity of two reference toxicants was evaluated in three biomodels representative of the ecosystem: Artemia sp., Physa cubensis and Lactuca sativa seeds. In the same, two patterns were used: potassium dichromate and copper sulphate. In both cases, a stock solution was prepared and serial dilutions of it, establishing 3 replicates per treatment. The control used consisted of water according to the habitat conditions of each species. The study was performed at controlled temperature and humidity. Were calculated mortality, expressed as LC50, for each experiment. A decrease in mortality was observed as the concentration of each toxicant decreased. It is concluded that potassium dichromate and copper sulphate can be used as standards in the calibration of ecotoxicological assays of the considered biomodels

Microbiological Quality Assessment by PCR and Its Antibiotic Susceptibility in Mangrove Crabs (Ucides cordatus) from Guanabara Bay, Rio de Janeiro, Brazil.

The bacteriological quality of crabs from three different mangroves (Itaóca, Suruí, and Piedade) from Rio de Janeiro state, Brazil, was investigated using conventional and molecular methods. The results revealed high counts for total coliforms in meat and hepatopancreas samples. PCR analyses identified 25 Escherichia coli colonies in the Itaóca, Piedade, and Suruí samples, detecting 13 enterotoxigenic colonies and 9 enteroaggregative colonies. Respectively, 12, 11, and 21 Vibrio parahaemolyticus strains were detected in the Itaóca, Piedade, and Suruí samples. Two V. cholerae strains were detected in the Piedade samples. The E. coli strains isolated in the present study showed resistance to gentamicin. E. coli strains from the Piedade samples showed 33% resistance to chloramphenicol and the strains also showed multiresistance to several antimicrobial agents with a MAR index ranging from 0.12 to 0.31. Vibrio strains from Piedade, Itaóca, and Suruí showed 86%, 78%, and 85% resistance, respectively, to ampicillin. The isolated Vibrio strains showed multiresistance to several antimicrobial agents, with a MAR index ranging from 0.12 to 0.25. The presence of these organisms in crab meat is an indication of microbial contamination, which may pose health risks to consumers when improperly cooked.

Microbiological and chemical characteristics of Brazilian kefir during fermentation and storage processes.

The microbial community composition and chemical characteristics of a Brazilian milk kefir sample produced during its manufacturing and refrigerated storage were investigated by culture-dependent and -independent methods and HPLC. Lactococcus lactis ssp. cremoris and ssp. lactis, Leuconostoc mesenteroides, Acetobacter lovaniensis, and Saccharomyces cerevisiae were isolated, whereas the detected bands on denaturing gel gradient electrophoresis corresponded to Lactobacillus kefiranofaciens, Lactobacillus kefiri, Lactobacillus parakefiri, and S. cerevisiae. After fermentation, lactic acid bacteria were present at levels of 10 log units, whereas acetic acid bacteria and yeast were present at levels of 7.8 and 6 log units, respectively. The lactic acid bacteria and yeast counts remained constant, whereas acetic acid bacteria counts decreased to 7.2 log units during storage. From fermentation to final storage, the pH, lactose content and citric acid of the kefir beverage decreased, followed by an increase in the concentrations of glucose, galactose, ethanol, and lactic, acetic, butyric, and propionic acids. These microbiological and chemical characteristics contribute to the unique taste and aroma of kefir. This research may serve as a basis for the future industrial production of this beverage in Brazil.

The present environmental scenario of the Nador Lagoon (Morocco).

In this paper, we present a multivariate approach (waters, sediments, microfauna) concerning the environmental state of the Nador Lagoon (NE Morocco). The normal water quality parameters (salinity, pH, nutrients) of the dominant marine flows are altered by local fecal water effluents, urban discharges, sewages derived from a water treatment station, and residues originated in a slaughterhouse. The geochemical analyses carried out in surficial sediment samples show very high concentrations of all metals studied near an old iron mine and moderate contents between Nador and its treatment station. Ostracods are good bioindicators of these environmental impacts, with the presence of a highly brackish assemblage in the quieter, more confined areas or the appearance of opportunistic species under hypoxic conditions. In addition, these microcrustaceans are absent in polluted bottom sediments or areas with high hydrodynamic gradients, whereas they decrease in both density and diversity if the subaerial exposure increases.

Farmacocinética y aclaramiento de ciprofloxacina y amikacina en hemodiálisis continua / Pharmacokinetics and clearence of ciprofloxacin and amikacin during continuous hemodialysis

We studied the pharmacokinetics and clearence of a 200 mg ciprofloxacin and a 500 mg amikacin intravenous dose during 5 continuous hemodialysis procedures in 5 patients with acute oliguric renal failure. Hourly blood and ultrafiltrate drug concentrations were measured during 8 hours. Dialysate flux (Qd) was 16.6 ml/min during the first hours and 33.2 ml/min thereafter. For each Qd, total ciprofloxacin clearence was 1.13ñ0.99 and 2.8ñ1.71 ml/min (p<0.001), diffusive clearence was 0.96ñ0.87 and 2.47ñ1.56 ml/min (p<0.005) and convective clearence was 0.16ñ0.17 and 0.33ñ0.2 ml/min (p<0.05). Likewise, total amikacin clearence was 3.47ñ1.31 and 4.18ñ0.53 ml/min (p<0.001), diffusive clearence was 2.97ñ1.24 and 3.86ñ0.52 ml/min and convective clearence was 0.50ñ0.47 and 0.32ñ0.29 ml/min (p=NS). Protein binding was 84 percent for ciprofloxacin and 77 percent for amikacin. It is concluded that during continuous hemodialysis with cuprofan membrane, the main transport mechanism of ciprofloxacin and amikacin is diffusive. Very low amounts of ciprofloxacin are depurated by the dialyser. Likewise, the shortening of amikacin half life suggest the presence of other elimination pathway and the need to use suplementary doses every 24 hours

Platelet function and biosynthesis of prostacyclin and thromboxane A2 in whole blood after aspirin administration in human subjects.

Small doses of aspirin have been shown to inhibit platelet thromboxane A2 while sparing vascular prostacyclin synthesis. Because leukocytes generate prostacyclin and participate in thrombosis along with platelets, the effects of three different doses of aspirin (40, 325 and 650 mg) on platelet function as well as on endogenous biosynthesis of thromboxane A2 and prostacyclin in whole blood were examined. In normal volunteers given a single 40 mg dose of aspirin, platelet aggregation and adenosine triphosphate release were inhibited for 24 hours. In contrast, platelet function was inhibited for 4 to 7 days in volunteers given 325 or 650 mg of aspirin. Platelet and whole blood generation of thromboxane A2 was inhibited less than 60% by the 40 mg dose, but almost completely by both the 325 and 650 mg doses. Likewise, whole blood generation of prostacyclin was inhibited 70% by the 40 mg dose and over 90% by the larger doses. Inhibition of thromboxane A2 as well as of prostacyclin was evident for 4 days with the 40 mg dose and for 7 days with the larger doses. Decreases in whole blood thromboxane A2 and prostacyclin with any dose of aspirin were of similar magnitude. These data indicate that aspirin in doses of 40 to 650 mg inhibits platelet function and biosynthesis of thromboxane A2 and prostacyclin in whole blood in human beings in a dose-dependent fashion.

Effects of nitrendipine and hydralazine on plasma catecholamines in essential hypertension.

We compared the efficacy and safety of nitrendipine with that of hydralazine in 21 subjects with essential hypertension. Nitrendipine or hydralazine was given in a double-blind manner after a placebo period. Dose was titrated to diastolic blood pressure (BP) less than or equal to 90 mm Hg and the dose established during titration was continued for 5 to 7 wk. Both supine and erect BP were decreased by both drugs, but heart rate was affected only minimally. Myocardial oxygen demand decreased only with nitrendipine (P less than 0.05), although the change may have been the result of somewhat higher systolic BP while on placebo. Hydralazine induced minimal changes in levels of plasma catecholamines, but plasma norepinephrine levels rose in subjects on nitrendipine. Side effects encountered with both drugs were much the same, although nitrendipine was more often associated with mild fatigue. There were mild elevations in liver function parameters in two subjects on nitrendipine. There was little difference between the effects of nitrendipine and hydralazine in hypertension.

Incidencia de cardiopatías congénitas en el hospital docente "Gral. Calixto García". Estudio en 6 años / Incidence of congenital heart disease at "Gral. Calixto García" Academic Medical Center. A six-year study

Se revisaron los expedientes clínicos de todos los pacientes egresados (53) del hospital docente "Gral. Calixto García", en un período de 6 años con el diagnóstico de alguna forma de cardiopatía congénita a su alta hospitalaria y arrojó una incidencia hospitalaria del 0,041 porciento (4,1 x 10 000 pacientes). Se encontró que la malformación cardíaca congénita más frecuente fue la comunicación interauricular (41,5 porciento); le siguió en orden de frecuencia la comunicación interventricular (20,7 porciento) y la tetralogía de fallot (9,4 porciento); correspondió a otros tipos el 28,3 porciento. El grupo de edad predominante de la serie fue 20-40 años; el sexo femenino fue el más frecuente. La letalidad general del grupo fue de 11,3 porciento. Fue llevada a cabo una revisión, comparación y discusión con los datos aparecidos en la literatura(AU)

Estenosis mitral subclínica

Se presentan ocho casos de valvulopatía mitral, 7 estenóticos y uno mitraórtico, en pacientes mayores de 54 años. El diagnóstico clínico es avalado por el estudio fonocardiográfico. La mayoría de los pacientes acuden al Hospital por afecciones ajenas a su valvulopatía, principalmente de orden quirúrgico. El grado de alteración vulvular se considera muy discreto produciendo escasas modificaciones hemodinámicas, la toma del miocardio muy leve, lo cual hace a la afección compatible con una relativamente larga vida(AU)

Estenosis pulmonar con tabique intacto Fonocardiografía

Se estudian los trazos forcardiográficos se ocho casos de estenosis pulmonar (c.t.i) y se comparan con los de 2 casos de trilogía de Fallot y cinco casos de tetralogía de Fallot. Se comprueba en los casos más típicos, características morfológicas que permiten identificar las estenosis pulmonares y las tetralogías de fallot.Se comprueba en los casos más típicos, características morfológicas que permiten identificar las estenosis pulmonares y las tetralogías de fallot. El signo más constante del fonocardiograma es la ocultación o no del 2do ruido por el soplo sistólico del eyección(AU)