LC-UV method to assay raloxifene hydrochloride in rat plasma and its application to a pharmacokinetic study

A specific, precise, and accurate LC-UV method was developed and validated to assay raloxifene hydrochloride in rat plasma. Raloxifene was analyzed after liquid-liquid extraction and quantified by reversed phase liquid chromatography (C18 column) using acetonitrile and ammonium acetate buffer 0.05 M (pH 4.0) as mobile phase at a flow rate of 1 mL.min-1 and UV detection at 287 nm. Retention times of raloxifene and internal standard (dexamethasone) were approximately 11 min and 14 min, respectively. Linearity was checked for a concentration range between 25 ng.mL-1 and 1000 ng.mL-1. Intra- and inter-day precision had relative standard deviation lower than 10% and 15%, respectively. Recovery from plasma was higher than 90%. Accuracy values were 98.21%, 99.70%, and 102.70% for lower, medium, and upper limits of quantification, respectively. Limit of quantification was 25 ng.mL-1. Drug stability was analyzed at room temperature using plasma kept in a freezer at -80 °C for 45 days after processing for 6 h and three freeze-thaw cycles. The advantages of the method developed include stability under different conditions and low limit of quantification. Its applicability was confirmed by the analysis of raloxifene levels in plasma samples in a designed pharmacokinetic study in rats after intravenous administration (5 mg.kg-1).

Transfusión de plasma y sus efectos adversos / Transfusion of plasma and its adverse effects

Me produjo alegría la solicitud del doctor Eugenio Matijasevic para hacer el comentario editorial sobre los efectos adversos de la transfusión de plasma, por tratarse de un tema de actualidad para la seguridad del paciente. su utilización se ha incrementado para el manejo de situaciones clínicas, como la deficiencia de factores de coagulación en pacientes con sangrado, o antes de un procedimiento invasivo, para revertir la warfarina, o en deficiencia de vitamina K en pacientes con sangrado o previo a un procedimiento invasivo de urgencia, cuando se presenta una coagulopatía dilucional, por ejemplo, en transfusión masiva, coagulación intravascular diseminada o coagulopatía de consumo en pacientes con hemorragia, en el cambio plasmático para tratamiento de púrpura trombocitopénica trombótica (PTT), en el manejo de deficiencias raras de proteínas, o para el tratamiento de deficiencias de factores de coagulación cuando los concentrados no se encuentran disponibles. Las anteriores constituyen las indicaciones para el uso racional del plasma de las guías británicas y americanas . Múltiples estudios han demostrado que una proporción importante, que puede llegar a cerca de 50% de las transfusiones de plasma, no se hacen de acuerdo a las guías, considerando que no están exentas de riesgo y que pueden llegar a producir ciertas complicaciones más comunes que otros componentes sanguíneos.

Preconditioning of the response to ischemia/ reperfusion-induced plasma leakage in hamster cheek pouch microcirculation

OBJECTIVE: Ischemic preconditioning and some drugs can protect tissues from injury by preserving microcirculation. This study evaluated vascular permeability in a hamster cheek pouch preparation using either short ischemic periods or bradykinin as preconditioning stimuli followed by 30 min of ischemia/reperfusion. METHOD: Sixty-six male hamsters were divided into 11 groups: five combinations of different ischemic frequencies and durations (one, three or five shorts periods of ischemia, separated by one or five minutes) with 10 min intervals between the ischemic periods, followed by 30 min ischemia/reperfusion; three or five 1 min ischemic periods with 10 min intervals between them followed by the topical application of histamine (2 µM); bradykinin (400 nM) followed by 30 min of ischemia/reperfusion; and three control groups (30 min of ischemia/reperfusion or histamine or bradykinin by themselves). Macromolecular permeability was assessed by injection of fluorescein-labeled dextran (FITC-dextran, MW= 150 kDa; 250 mg/Kg body weight), and the number of leaks/cm2 was counted using an intravital microscope and fluorescent light in the cheek pouch. RESULTS: Plasma leakage (number of leaks/cm²) was significantly reduced by preconditioning with three and five 1 min ischemic periods, one and three 5 min ischemic periods and by bradykinin. Histamine-induced macromolecular permeability was also reduced after three periods of 5 min of ischemia. CONCLUSION: Short ischemic periods and bradykinin can function as preconditioning stimuli of the ischemia/reperfusion response in the hamster cheek pouch microcirculation. Short ischemic periods also reduced histamineinduced macromolecular permeability.

Effect of natural honey on human platelets and blood coagulation proteins

Present study was conducted to determine the effects of honey on blood hemostasis, in-vitro effect of honey was observed on platelet aggregation and blood coagulation employing, activated partial prothrombin time [aPTT], prothrombin time [PT], thrombin time [TT] and fibrinogen levels in blood. Honey samples showed moderate inhibition of platelet aggregation with IC[50] 5-7.5%. The coagulation assays showed that at higher concentrations [>/= 15%] honey samples increased whole blood clotting time. When assayed in platelet poor plasma [PPP], honey samples significantly [P >/= 0.005] prolonged aPTT, PT, and TT. The honey samples [at 3.75% and 7.5% concentrations] cause mean increment of aPTT = 19 +/- 10% and 62 +/- 10%; PT 6 +/- 5% and 40 +/- 5%; TT 35 +/- 15% and 112 +/- 30% respectively. Moreover, PPP isolated from whole blood pre-incubated with honey samples [9.0% for 10 minutes] showed mean prolongation of aPTT, PT and TT of 45 +/- 21%, 26 +/- 9% and 105 +/- 24% respectively. Interestingly, incubation of honey at 6.25% and 11.75% concentrations in PPP considerably [P >/= 0.005] reduced fibrinogen levels i.e. 13 +/- 4% and 86 +/- 30% respectively. The present study outlines the inhibitory effect of natural honey on platelet aggregation and blood coagulation. These observations provide first line data for modulatory role [s] of honey on process of hemostasis

Differential effects of isoproterenol on the activity of angiotensin-converting enzyme in the rat heart and aorta

The excessive stimulation of beta-adrenergic receptors in the heart induces myocardial hypertrophy. There are several experimental data suggesting that this hypertrophy may also depend, at least partially, on the increase of local production of angiotensin II secondary to the activation of the cardiac renin-angiotensin system. In this study we investigated the effects of isoproterenol on the activity of angiotensin-converting enzyme (ACE) in the heart and also in the aorta and plasma. Male Wistar rats weighing 250 to 305 g were treated with a dose of (ñ)-isoproterenol (0.3 mg kg-1 day-1, N = 8) sufficient to produce cardiac hypertrophy without deleterious effects on the pumping capacity of the heart. Control rats (N = 7) were treated with vehicle (corn oil). The animals were killed one week later. ACE activity was determined in vitro in the four cardiac chambers, aorta and plasma by a fluorimetric assay. A significant hypertrophy was observed in both ventricular chambers. ACE activity in the atria remained constant after isoproterenol treatment. There was a significant increase (P<0.05) of ACE activity in the right ventricle (6.9 = 0.9 to 8.2 = 0.6 nmol His-Leu g-1 min-1) and in the left ventricle (6.4 ñ 1.1 to 8.9 ñ 0.8 nmol His-Leu g-1 min-1). In the aorta, however, ACE activity decreased (P<0.01) after isoproterenol (41 = 3 to 27 = 2 nmol His-Leu g-1 min-1) while it remained unchanged in the plasma. These data suggest that ACE expression in the heart can be increased by stimulation of beta-adrenoceptors. However, this effect is not observed on other local renin-angiotensin systems, such as the aorta. Our data also suggest that the increased sympathetic discharge and the elevated plasma concentration of catecholamines may contribute to the upregulation of ACE expression in the heart after myocardial infarction and heart failure

Concentraçöes plasmáticas e foliculares de IGF-I em pacientes submetidas a FIV / Folicular and plasm IGF-I levels in IVF patients

RETROSPECTIVA: diversos estudos têm atribuído ao IGF-I a atividade gonadotrófica sobre as células foliculares, exercendo um efeito parácrino na regulaçäo da esteroidogênese. Entretanto, a verdadeira origem do IGF-I encontrado no fluido folicular ovariano permanece obscura. OBJETIVOS: determinar a relaçäo entre as concentraçöes de IGF-I folicular e sérico em 22 pacientes submetidas a fertilizaçäo in vitro. METODOLOGIA: foram avaliadas as concentraçöes de IGF-I no plasma e no fluido folicular de 22 mulheres submetidas a fertilizaçäo in vitro. As amostras foram obtidas na ocasiäo da captaçäo de oócitos e dois dias antes, na ocasiäo da administraçäo de HCG. O IGF-I foi dosado em cada uma das amostras pelo método imunorradiométrico. RESULTADOS: houve correlaçäo dos níveis de IGF-I entre o plasma e o fluido folicular, sugerindo um provável equilíbrio dessa proteína entre os dois compartimentos. CONCLUSöES: esses achados säo condizentes com relatos prévios da literatura e sugerem que a maior parte do IGF-I presente no fluido folicular seja derivado de difusäo a partir do plasma e que a produçäo local desse fator de crescimento no interior do ovário seja pouco expressiva.

Antioxidant activity of the microalga Spirulina maxima

Spirulina maxima, which is used as a food additive, is a microalga rich in protein and other essential nutrients. Spirullina contains phenolic acids, tocopherols and Beta-carotene which are known to exhibit antioxidant properties. The aim of the present study was to evaluate the antioxidant capacity of a Spirulina extract. The antioxidant activity of a methanolic extract of Spirulina was determined in vitro and in vivo. The in vitro antioxidant capacity was tested on a brain homogenate incubated with and without the extract at 37 degrees Celsius. The IC(50) (concentration which causes a 50 per cent reduction of oxidation) of the extract in this system was 0.18 mg/ml. The in vivo antioxidant capacity was evaluated in plasma and liver of animals recceiving a daily dose of 5 mg for 2 and 7 weeks Plasma antioxidant capacity was measured in brain homogenate incubated for 1 h at 37 degrees Celsius. The production of oxidized compounds in liver after 2 h of incubation at 37 degrees Celsius was measured in terms of thiobarbituric acid reactant substances (TBARS) in control and experimental groups. Upon treatment, the antioxidant capacity of plasma was 71 per cent for the experimental group and 54 per cent for the control group. Data from liver spontaneous peroxidation studies were not significantly different between groups. The amounts of phenolic acids, alpha-tocopherol and Beta-carotene were determined in Spirulina extracts. The results obtained indicate that Spirulina provides some antioxidant protection for both in vitro and in vitro and vivo systems.

Estudio de los parámetros clínico-bioquímicos antes y después de rehidratación oral en becerros diarreicos / Study of clinical biochemical parameters before and after oral rehydration in calves with diarrhea

La diarrea que crusa con deshidratación en becerros se presenta muy frecuentemente durante las primeras semanas después del nacimiento, constituye la causa más importante de mortalidad. En este estudio fue evaluada la eficiencia de la rehidratación oral en becerros diarreicos con deshidratación ligera con base en el examen físico de los animales y prueba de laboratorio. Para la rehidratación oral en 29 becerros diarreicos de raza Holstein-Friesian de entre 2 y 19 días de edad, se utilizó una mezcla compuesta por 42 g de NaCl, 40 g de NaHCO3, 18 g de KCl y 200 g de glucosa que fueron diluidas en 101 de agua a 38ºC. A cada becerro se le ofreció 61 de esta solución por día dividida en 3 dosis, el tratamiento duró 2-3 días. A los becerros se les realizó examen físico y los análisis bioquímicos y hemáticos antes y después de la rehidratación oral. Exámenes bacteriológicos, parasitológicos y virológicos de heces se hicieron antes de la rehidratación. En 26 becerros se confirmó deshidratación ligera y deshidratación moderada en 3. En el examen de heces se detectó rotavirus y Criptosporidium. Antes de la rehidratación oral se obtuvieron los siguientes valores en sangre: pH, 7.284; exceso de base (EB), -5.86 mmol/l; pCO2, 39.3 mmHg; hematocrito (Ht), 38.9 por ciento; en plasma: urea, 55.5 mg/dl; glucosa, 65.2 mg/dl; proteínas totales (Pt), 6.21 g/dl; Na, 132.6 mmol/l; K, 5.23 mmol/l: Cl, 102.7 mmol/l; Ca, 2.82 mmol/l. Los cambios más importantes en becerros diarreicos con deshidratación ligera fueron acidosis metabólica parcialmente compensada, ligera uremia prerrenal, hipoglucemia, hiponatremia y hemoconcentración. Después de la rehidratación los valores en sangre se normalizaron, obteniéndose en sangre: pH de 7.366; EB, 0.30 mmol/l; pCO2, 43.2 mmHg; Ht, 32 por ciento; en plasma: urea, 27.2 mg/dl; glucosa, 81.6 mg/dl; Pt, 5.90 g/dl; Na, 138.1 mmol/l; K, 4.47 mmol/l; Cl, 99.5 mmol/l; Ca, 1.58 mmol/l; y quedaron dentro de los rangos de referencia. La rehidratación oral fue exitosa en 27 de los 29 becerros

Alteraçöes metabólicas e funcionais em células e órgäos do sistema imunológico de ratos induzidas pela administraçäo intragástrica do óleo de peixe / Metabolic and functional changes in cells and organs of immune system of rats due to the fish oil administrated by gavage

O consumo de cápsulas de óleo de peixe (OP) por humanos visa a atenuaçäo dos sintomas e prevençäo de várias patologias. As alteraçöes metabólicas e funcionais em células e órgäos do sistema imunológico causadas pelo OP pela administraçäo intragástrica (AIG) foram avaliadas. Ratos recém-desmamados (50-70 g) foram submetidos a AIG diária com óleo de peixe, óleo de soja ou manteiga de cacau (0,4 por cento do peso), por 28 dias. Os dados da AIG do OP foram também comparados com os da dieta enriquecida com OP. Foram avaliados: aumento de permeabilidade vascular (reaçäo anafilática), funcionalidade de macrófagos (produçäo de 'H IND. 2O IND. 2', 'O IND. 2' e fagocitose), proliferaçäo de linfócitos, a atividade máxima das enzimas: hexoquinase, glicose-6-fosfato desidrogenase, citrato sintase (metabolismo de glicose), catalase, glutationa peroxidase e superóxido dismutase (antioxidantes) no baço, linfonodo mesentérico e timo. A concentraçäo de TBARs nos mesmos órgäos e no plasma e a capacidade antioxidante do plasma foram também determinadas

Concentraciones sanguíneas de amikacina durante la primera semana de vida en neonatos pretérmino / Blood amikacin concentration during the first week of life in preterm neonates

Objetivo. Informar sobre las concentraciones sanguíneas de amikacina en un grupo de 10 niños durante la primera semana de vida posnatal, con peso promedio de 1.640 ñ .330 Kg, edad gestacional de 34 ñ 2 semanas y con diagnóstico de septicemia, internados en la Unidad de Cuidados Intensivos Neonatales del Instituto Nacional de Perinatología. Material y método. Todos los niños recibieron 7.5 mg/Kg de amikacina por vía endovenosa durante 30 min, dosis que se continuó cada 12 horas en 6 niños y se modificó en 4. El primero y quinto día de tratamiento se determinaron a los 30 min. posdosis de Cpmax y a las 12 horas posdosis la Cpmin, así como la vida media de eliminación (t½el), el volumen de distribución (Vd) y la depuración (Cl). Se consideraron valores terapéuticos entre 15 y 30 µg/mL para la Cpmax y menores de 8 µg/mL para la Cpmin. Resultados. En 6 niños la Cpmax durante la primera dosis fue menor de 15 µg/mL y Cpmin en otros 4 niños fue mayor de 8 µg/mL. Debido a lo anterior, a un niño se le administró la dosis cada 24 horas y a los otros 3 la dosis se disminuyó a 5 mg/Kg cada 24 horas. Para el quinto día de tratamiento en sólo 3 de los 6 niños el grupo en que se mantuvo el esquema de dosis inicial se obtuvieron Cpmax y Cpmin dentro de los valores terapéuticos. Conclusiones. En este grupo de pacientes la administración de amikacina a 7.5 mg/Kg/12 horas no es adecuado por tener un alto riesgo de producir concentraciones tóxicas cuando se alcanza el estado de equilibrio. Se recomienda establecer un esquema de dosificación más óptimo con una dosis de mantenimiento menor, aumentar su intervalo de administración o ambos

Pharmacokinetics of oral ranitidine in Mexicans

The pharmacokinetics of oral ranitidine were studied in 24 Mexican male healthy volunteers. Subjects received a tablet containing 150 mg of ranitidine (Azantac TM, Glaxo de Mexico, Mexico, City) after an overnight fast and blood samples were drawn at several times for a period of 24 h. Ranitidine concentration in plasma was measured by high performance liquid chromatography and pharmacokinetic parameters were determined by non-compartmental analysis. Ranitide plasma concentration increased with time, reaching a maximum of (mean ñ SEM) 484 ñ 34 ng/ml in 2.7 ñ 0.2 h. Plasma levels then decayed with a terminal half-life of 4.8 ñ 0.3 h. The area under the plasma concentration against time curve was 2440 ñ 126 ngh/ml. Oral ranitidine pharmacokinetic parameters in mexicans appeared to be similar to those previously reported for caucasians

Effects of organophosphorus insecticide phosphomidon on antioxidant defence components of human erythrocyte and plasma.

Effect of organophosphorus insecticide, phosphomidon (250 and 500 ppm) on human erythrocyte and plasma were studied in vitro to get insight into the cellular antioxidant defence mechanism and malondialdehyde formation. The antioxidant defence system of erythrocyte was altered as evident by depression of glutathione reductase, glucose 6 phosphate dehydrogenase, whereas the level of reduced glutathione, glutathione peroxidase, glutathione-S-transferase, superoxidedismutase and catalase were stimulated. In the case of plasma fraction, glutathione reductase, glutathione peroxidase, glutathione-s-transferase, glucose-6-phosphate dehydrogenase, superoxide dismutase and levels of reduced glutathione were significantly depressed and the malondialdehyde formation and catalase activity were elevated indicating the less adaptive response of plasma to protect it from oxidative damage.

Níveis plasmáticos e eritrocitário de cromo após intoxicaçäo aguda por dicromato de potássio / Levels of Chromium in plasma and red blood cells after acute poisonning by postassium dichromate

Foram coletadas amostras de sangue, durante 23 dias consecutivos, e nos 26§, 29§ e 40§ dias, de um indivíduo do sexo masculino, após tentativa de suicídio, ao ingerir cerca de 10 gramas de K2 Cr2 O7. Utilizando-se EAA-Zeeman, realizaram-se as determinaçöes de cromo total e de cromo (VI), no plasma (Cr-P) e nos eritrócitos (Cr-E). Os percentuais de Cr (VI) e as relaçöes Cr-P/Cr-E permitiram obter informaçöes quanto à distribuiçäo de cromo no compartimento sangüíneo, e aos processos de reduçäo, durante intoxicaçäo aguda

Valoración del plasma en pacientes con prótesis valvular cardíaca y tratamiento con anticoagulante / Plasma assessments in patients with cardiac valve prosthesis undergoing oral anticoagulant therapy

Se estudió el efecto prolongado de la warfarina y el pellentán sobre algunos componentes del plasma (ácido úrico, glicemia, urea, creatinina, colesterol y transaminasa glutamicopirúvica), según la metodología recomendada para su determinación, en 48 pacientes adultos con prótesis valvular cardíaca y tratamiento con anticoagulante oral. La edad osciló entre 17 y 65 años, con una media de 36. Hubo un predominio del sexo femenino. Para el grupo control se estudiaron 20 pacientes adultos preuniversitarios cuyas edades oscilaron entre 15 y 18 años, con una media de 17. Los pacientes para ambos anticoagulantes se agruparon en dos subgrupos según el tiempo de tratamiento: 1) entre 2 y 23 meses y 2) con más de 23 hasta 60 meses. No se encontraron diferencias estadísticamente significativas (p > 0,05) entre el grupo control y cada uno de los subgrupos con anticoagulantes