Amido Black 10B a widely used azo dye causes DNA damage in pro- and eukaryotic indicator cells.

Acid Black 10B (AB10B) is widely used for the production of textiles, leather and prints. It is a representative of azo dyes and it is well documented that some of these compounds are mutagenic per se, and that cleavage products (in particular aromatic amines) may cause damage of the genetic material and cancer. Since no toxicological data on AB10B have been published, we evaluated its mutagenic activity in Salmonella/microsome assays and studied its acute toxic and genotoxic properties in a human derived liver cell line (HepG2) which retained the activities of drug metabolizing enzymes. The compound did not cause cytotoxicity (MTT assay), but clear genotoxic effects were detected in pro- and eukaryotic indicator cells. Dose dependent induction of his+ revertants was seen in strain TA98 which detects frameshift mutations without metabolic activation; a more pronounced effect was seen in its derivative YG1024 which overexpresses N-acetyltransferase. Induction of single/double strand breaks by Comet assay was detected with concentrations > 0.125 mg/mL in liver derived cells; as well as increased rates for micronucleus (reflecting structural and numeric chromosomal aberrations) and nuclear buds which are a consequence of gene amplifications were seen with a higher dose (2.0 mg/mL) (p < 0.05; Tukey's test). The mutational pattern which was observed in the bacterial tests indicates that the cleavage product p-nitroaniline may cause the genotoxic effects of the dye. Our findings indicate that exposure of humans and the release of the compound into the environment may lead to adverse effects due to its DNA damaging activity.

Toxicity of synthetic flavorings, nature identical and artificial, to hematopoietic tissue cells of rodents / Toxicidade de aromatizantes alimentares sintéticos idênticos aos naturais e artificiais a células de tecido hematopoiético de roedores

The goal of this study was to analyze cytotoxicity, genotoxicity and mutagenicity to bone marrow cells of mice of nature identical synthetic flavorings, passion fruit and strawberry, and artificial synthetic flavorings, vanilla, chocolate, tutti-frutti and cookie, at doses 0.5; 1.0; 2.0; 5.0 and 10.0 mL/kg. The additives were given to the animals by gavage in a single daily application for seven days. Data were subjected to analysis of variance (ANOVA) followed by post Tukeys post hoc test, p < 0.05. Animals treated with 2.0; 5.0 and 10.0 mL/Kg of flavorings chocolate, strawberry and cookie, and 5.0 and 10.0 mL/Kg of flavorings vanilla and passion fruit died on the fifth and sixth day of the experiment, respectively. The doses 0.5 and 1.0 mL/Kg of the six additives significantly reduced erythropoiesis in the examined tissue. Also, treatments 0.5 and 1.0 mL/Kg of chocolate, and 1.0 mL/Kg of strawberry and biscuit induced the formation of micronuclei in the bone marrow erythrocytes, at a significant frequency. Therefore, under the study conditions, the six microingredients analyzed were cytotoxic and genotoxic, and additives strawberry, chocolate and cookie were also mutagenic in at least one of the evaluated doses.(AU)

Os aromatizantes são essenciais para a indústria na confecção de alimentos industrializados. Porém, pouco se sabe sobre o potencial tóxico desses microingredientes alimentares. Dessa forma, objetivou-se neste trabalho analisar, em células de medula óssea de camundongos, a citotoxicidade, genotoxicidade e mutagenicidade de aromatizantes alimentares sintéticos idênticos ao natural, de maracujá e morango, e artificiais, de baunilha, chocolate, tutti-frutti e biscoito, nas doses 0,5; 1,0; 2,0; 5,0 e 10,0 mL/Kg. Os aditivos foram administrados aos animais via gavagem em aplicação diária única durante sete dias. Os dados obtidos foram submetidos ao procedimento estatístico ANOVA com pós teste de Tukey, com p < 0.05. Os animais tratados com 2,0; 5,0 e 10,0 mL/Kg dos aromatizantes de chocolate, morango e biscoito, e 5,0 e 10,0 mL/Kg dos aromatizantes de baunilha e maracujá vieram a óbito no quinto e sexto dia de experimento, respectivamente. As doses 0,5 e 1,0 mL/Kg dos seis aditivos reduziram significativamente a eritropoiese do tecido analisado. Ainda, os tratamentos 0,5 e 1,0 mL/kg de chocolate, e 1,0 mL/Kg de morango e biscoito induziram a formação de micronúcleos aos eritrócitos de medula em frequência significante. Portanto, nas condições de estudo estabelecidas, os seis microingredientes analisados foram citotóxico e genotóxicos, e os aditivos de morango, chocolate e biscoito também foram mutagênicos em pelo menos uma das doses avaliadas.(AU)

Low dose of methyltestosterone in ovariectomised rats improves baroreflex sensitivity without geno- and cytotoxicity.

This study evaluated the effects of the isolated use of a low dose of methyltestosterone (MT) on cardiovascular reflexes and hormonal levels and its geno- and cytotoxic safety in ovariectomized rats. Female Wistar rats were divided into four groups (n = 6), respectively: SHAM (received vehicle methylcellulose 0.5%), SHAM + MT (received MT 0.05 mg/kg), OVX (received vehicle), and OVX + MT (received MT). Twenty-one days after ovariectomy, treatment was given orally daily for 28 days. The Bezold-Jarisch reflex (BJR) was analyzed by measuring the bradycardic and hypotensive responses elicited by phenylbiguanide (PBG) administration. The baroreflex sensitivity (BRS) was evaluated by phenylephrine and sodium nitroprussite. Myocyte hypertrophy was determined by morphometric analysis of H&E stained slides. Biochemical data were analyzed, as well as micronucleus assay. MT improved BRS and increased testosterone values, but did not change estradiol in the OVX group. MT did not promote changes in mean arterial pressure, heart rate, BJR, serum concentrations of troponin I, weight and histopathology of the heart. MT was able to restore the BRS in OVX rats. The geno- and cytotoxic safety of the MT was demonstrated by the absence of an increase in the micronucleus (PCEMN) or change in the ratio between normochromatic erythrocytes and polychromatic erythrocytes (NCE/PCE).

Citotoxicidad in vitro y potencialidades de los compuestos quinoides como agentes antitumorales / Cytotoxicity in vitro and potential of quinoid compounds as antitumor agent

La búsqueda e identificación de nuevos compuestos activos para la terapéutica del cáncer se ha centrado esencialmente en la investigación de productos naturales y de sus análogos sintéticos. El presente trabajo pretende sistematizar los conocimientos sobre las bases moleculares de la actividad citotóxica de los compuestos quinoides y su uso como agente antitumoral. Se realizó una revisión de artículos originales, de corte experimental, publicados en la década 2004-2014 en algunas bases de datos de la Biblioteca Virtual de Salud (BVS). Se constató que numerosos estudios han avalado la capacidad de los productos quinoides de inhibir el crecimiento celular, sustentado en sus posibilidades de dañar al ADN por estrés oxidativo y de interactuar de modo biorreductivo con otras biomoléculas. Además, que la potencia de la citotoxicidad de los compuestos quinoides se incrementa ante cadenas laterales alquiladas y anillos aromatizados unidos al motivo quinona. Las evidencias experimentales sugieren un promisorio futuro de estas moléculas como agentes antitumorales, en base a su citotoxicidad y elevada selectividad ante líneas celulares neoplásicas(AU)

The search and identification of new active compounds for cancer therapy has focused mainly on research of natural products and their synthetic analogs. This paper aims to systematize the knowledge of the molecular basis of the cytotoxic activity of the quinoid compounds and their use as an antitumor agent. A review was performed on original articles, experimental section, published in the 2004-2014 decade in some databases of the Virtual Health Library (VHL). Numerous studies have supported the ability of quinoid products inhibiting cell growth, based on their ability to damage DNA by oxidative stress and thus have a biorreductive interaction with other biomolecules. Furthermore, the power of cytotoxicity increases quinoid compounds alkylated with side chains attached to rings and quinone flavored motif. Experimental evidence suggests a promising future of these molecules as antitumor agents, based on their high selectivity and cytotoxicity against neoplastic cell lines(AU)

Citotoxicidad in vitro y potencialidades de los compuestos quinoides como agentes antitumorales / Cytotoxicity in vitro and potential of quinoid compounds as antitumor agents

La búsqueda e identificación de nuevos compuestos activos para la terapéutica del cáncer se ha centrado esencialmente en la investigación de productos naturales y de sus análogos sintéticos. El presente trabajo pretende sistematizar los conocimientos sobre las bases moleculares de la actividad citotóxica de los compuestos quinoides y su uso como agente antitumoral. Se realizó una revisión de artículos originales, de corte experimental, publicados en la década 2004-2014 en algunas bases de datos de la Biblioteca Virtual de Salud (BVS). Se constató que numerosos estudios han avalado la capacidad de los productos quinoides de inhibir el crecimiento celular, sustentado en sus posibilidades de dañar al ADN por estrés oxidativo y de interactuar de modo biorreductivo con otras biomoléculas. Además, que la potencia de la citotoxicidad de los compuestos quinoides se incrementa ante cadenas laterales alquiladas y anillos aromatizados unidos al motivo quinona. Las evidencias experimentales sugieren un promisorio futuro de estas moléculas como agentes antitumorales, en base a su citotoxicidad y elevada selectividad ante líneas celulares neoplásicas(AU)

The search and identification of new active compounds for cancer therapy has focused mainly on research of natural products and their synthetic analogs. This paper aims to systematize the knowledge of the molecular basis of the cytotoxic activity of the quinoid compounds and their use as an antitumor agent. A review was performed on original articles, experimental section, published in the 2004-2014 decade in some databases of the Virtual Health Library (VHL). Numerous studies have supported the ability of quinoid products inhibiting cell growth, based on their ability to damage DNA by oxidative stress and thus have a biorreductive interaction with other biomolecules. Furthermore, the power of cytotoxicity increases quinoid compounds alkylated with side chains attached to rings and quinone flavored motif. Experimental evidence suggests a promising future of these molecules as antitumor agents, based on their high selectivity and cytotoxicity against neoplastic cell lines(AU)

Valoración de dos métodos de tinción en ensayos de citotoxicidad sobre líneas celulares tumorales / Assessing two staining methods for cytotoxicity tests on tumor cell lines

En la estimación de la posible citotoxicidad de extractos o compuestos en proceso de prospección se emplean métodos de tinción celular como aproximación indirecta para la medición masa celular viable. En ensayos de citotoxicidad sobre las líneas celulares SiHa, MCF-7 y MKN-45 se comparan el método de tinción sulforodamina B (SRB), que es un ensayo de tipo terminal, con el uso de resazurina propuesta como poco tóxica para las células. La comparación de los métodos se hizo en términos de porcentaje de supervivencia donde se evaluó la sensibilidad de las líneas a tres compuestos sintéticos durante un periodo de tratamiento de 48 horas usando como referencia de actividad doxorrubicina HCl, un medicamento empleando en cáncer. Los datos obtenidos en los dos tipos de ensayos sometidos a una prueba de correlación mostraron que no hay diferencias significativas en ambos métodos permitiendo la comparación entre estos bajo las condiciones usadas.

Cell staining methods are commonly used for estimating extracts or compounds’ potential cytotoxic activity when prospecting for indirect quantitative measurement of cell growth and viability. This work compared the sulphorhodamine B (SRB) staining method, which is a terminal cell density measuring assay, and the resazurin method, a cell proliferation assay which is supposed to be less toxic for the cell. The methods were compared in terms of percentage survival by evaluating MCF-7, MKN-45 and SiHa cell line sensitivity to three synthetic compounds using a 48-hour treatment period and doxorubicin HCl (a drug used in cancer treatment) as reference activity. A correlation test using the data obtained from the assays showed that there was no significant difference between the methods in the conditions used here.

Dynamics and kinetics of natural killer cell cytotoxicity in human malaria as evaluated by a novel stepwise cytotoxicity assay.

Malaria causes important functional alterations of the immune system, but several of them are poorly defined. To evaluate thoroughly the natural killer cell cytotoxicity in patients with malaria, we developed a technique capable to assess both the dynamics and the kinetics of the process. For the kinetics assay, human peripheral blood mononuclear cells were previously incubated with K562 cells and kept in agarose medium, while for the dynamics assay both cells were maintained in suspension. NK activity from patients with vivax malaria presented a kinetics profile faster than those with falciparum malaria. NK cytotoxicity positively correlated with parasitemia in falciparum malaria. The dynamics of NK cytotoxicity of healthy individuals was elevated at the beginning of the process and then significantly decreased. In contrast, malaria patients presented successive peaks of NK activity. Our results confirmed the occurrence of alteration in NK cell function during malaria, and added new data about the NK cytotoxicity process.

Dynamics and kinetics of natural killer cell cytotoxicity in human malaria as evaluated by a novel stepwise cytotoxicity assay

Malaria causes important functional alterations of the immune system, but several of them are poorly defined. To evaluate thoroughly the natural killer cell cytotoxicity in patients with malaria, we developed a technique capable to assess both the dynamics and the kinetics of the process. For the kinetics assay, human peripheral blood mononuclear cells were previously incubated with K562 cells and kept in agarose medium, while for the dynamics assay both cells were maintained in suspension. NK activity from patients with vivax malaria presented a kinetics profile faster than those with falciparum malaria. NK cytotoxicity positively correlated with parasitemia in falciparum malaria. The dynamics of NK cytotoxicity of healthy individuals was elevated at the beginning of the process and then significantly decreased. In contrast, malaria patients presented successive peaks of NK activity. Our results confirmed the occurrence of alteration in NK cell function during malaria, and added new data about the NK cytotoxicity process.

A malária causa importantes alterações do sistema imunitário, muitas ainda mal definidas. Para permitir uma avaliação abrangente da atividade citotóxica das células natural killer em pacientes com malária, desenvolvemos um teste capaz de avaliar concomitantemente a dinâmica e a cinética do processo. Para a avaliação da cinética, células mononucleares do sangue periférico interagiram com células K562 e foram mantidas em agarose, enquanto para avaliar a dinâmica as células eram mantidas em suspensão. A cinética da atividade citotóxica das células NK foi mais rápida em pacientes com Plasmodium vivax, do que naqueles infectados com P. falciparum. Nestes, houve correlação positiva entre a atividade citotóxica das células NK e a parasitemia. O padrão da dinâmica da atividade citotóxica nos pacientes com malária foi bem diferente daquele apresentado pelos indivíduos sadios. Enquanto nestes, a atividade estava muito aumentada no início da incubação das células, sofrendo posteriormente uma redução, nos indivíduos infectados foram detectados sucessivos picos de atividade citotóxica. Nossos resultados confirmam a ocorrência de alteração funcional das células NK na malária humana e acrescentam novos dados sobre a dinâmica e a cinética da atividade citotóxica.

Veneno de Bothrops jararaca modificado com PEG (monometoxipolietileno glicol) para elaboração de um adjuvante complexado à partícula antigênica / Bothrops jararaca venon modified for elaboration of complexed adjuvant to the antigenic particule with (monomethoxypolyethylene glycol (mPEG)

Enzimas, biofármacos e produtos de origem biológica de modo geral sempre foram obstáculos para o uso terapêutico. Isto em função dos riscos de reação adversa que poderiam ocasionar bem como a indução de uma resposta imunológica desejável ou não. A utilização do monometoxipolietileno glicol (mPEG) conjugado a proteínas e enzimas trouxe novas perspectivas de utilização de substâncias naturais como substâncias farmacológicas ativas, pois o fato de estarem conjugadas a um polímero inerte atribui uma nova estrutura físico-química a essas substâncias, diminuindo consideravelmente os riscos de anafilaxia e a biodegradação por formação de complexos antígeno-anticorpo...

HCV core protein-expressing DNA vaccine induces a strong class I-binding peptide DTH response in mice.

The hepatitis C virus (HCV) core protein-encoding sequence (HCcAg) is the most conserved gene in HCV genome and therefore may be useful to study broadly reacting T-cell epitopes. In this study BALB/c and C57BL/6 mice were immunized with a DNA based vaccine expressing the first 176 aa of HCcAg (pIDKCo). After i.m or i.p injection of pIDKCo in BALB/c mice, a detectable INF-gamma secreting response to the relevant class I-binding peptide DLMGYIPLVGA (P1) (aa 132-142) was detected suggesting the induction of HCcAg specific CD8(+) T-cell effectors. CD8(+) T-cell responses were also monitored in vivo by T-cell-mediated DTH reactions after subcutaneous injection of class I-binding viral peptide P1. pIDKCo induced a strong P1-specific DTH response in both i.m and i.p immunized mice. To evaluate the T-cell response induced by pIDKCo in C57BL/6 mice, an HCcAg epitope was predicted based upon it containing the H-2K(b) binding motif XXXXF/YXXL (DLMGYIPL (P2)). pIDKCo induced a strong P2-specific DTH response with similar kinetics of swelling response to that observed in BALB/c mice. Previously, it had been demonstrated that only activated and protective CD8(+) effector T cells could mediate a specific DTH in footpads of virally infected mice after local injection of viral class I-binding peptides. Hence, pIDKCo could prime a strong HCcAg-specific T-cell response in mice with the potential capacity to exert their specific effector functions in peripheral tissues.

Analysis of AHG-PRA and ELISA-PRA in kidney transplant patients with acute rejection episodes.

Many centers determined a significant correlation between post-transplant anti-HLA antibodies production and clinical outcome. In order to confirm this correlation and ascertain the sequential appearance of anti-HLA antibodies, we compared the ELISA (ELISA-PRA) and the anti-human globulin enhanced complement-dependent lymphocytotoxicity panel-reactive antibodies test (AHG-PRA) with the occurrence of acute rejection episodes. Thirty patients who underwent kidney transplantation between December 1998 and October 1999 were assayed. One pre-transplant and 10 post-transplant serum samples were tested from each recipient except from one of them who lost his graft on the 1 week post-transplant. The diagnosis of acute rejection episode was based on classical criteria (fever, graft swelling and tenderness, oliguria, weight gain) and a rapid rise in serum creatinine levels, confirmed by an allograft biopsy graded by the Banff working classification. The 322 pre- and post-transplant serum specimens were tested by AHG-PRA methodology and 298 of them by the ELISA-PRA. The agreement coefficient (kappa) for both methodologies was 0.63. There were 27 acute rejection episodes in 19 patients. AHG-PRA results were significantly correlated (Hazard ratio=10.06; P=0.006) with this occurrence. These data were not confirmed with the ELISA-PRA procedure. Our results suggest that a routine post-transplant AHG-PRA test offers an early risk assessment of acute rejection episodes and may be a useful method for monitoring the kidney transplant evolution.

Ação do soro de cabra anti-soro de coelho imunizado ou não com células linfóides do doador sobre o alotransplante cardíaco em ratos / Action of goat serum antiserum of rabbit immunized or not with donor lymphoid cells about the cardiac allograft in rats

Introdução: A rejeição imunológica é uma das principais causas da perda de órgãos transplantados. A tentativa do controle da reação imunológica é clinicamente feita através da imunossupressão inespecífica e experimentalmente também por bloqueio específico. O alotransplante cardíaco em ratos pela técnica de ONO,K é um bom método para avaliação clínica da rejeição e de estudos voltados para o controle da rejeição. Objetivo estudar o efeito de um anti-antisoro linfocitário, anti-linfócitos do doador sobre a rejeição do alotransplante cardíaco de ratos Wistar para ratos Holtzman. Métodos: O soro anti-linfocitário (SAL) foi obtido através da imunização de coelhos com linfócitos obtidos de gânglios linfáticos da cadeia mesentérica de ratos Wistar, em solução de Tyrode, contendo 3x109 células/ ml. A inoculação de 3 coelhos foi feita com 1 ml da suspensão celular e 1 ml de adjuvante completo de Freund. Duas semanas após a primeira inoculação fez-se 4 doses semanais de reforço. Os coelhos foram sangrados na 5a semana, quando então foram separados os soros. A titulação dos soros foi realizada pelo teste de citotoxicidade, sendo verificado que ambos apresentaram título 1:1024. A dosagem de proteínas mostrou albumina com 3,1 e 2,7g por cento e globulinas com 3,5 e 2,9g por cento, sendo o normal 3,7 e 2,2g por cento respectivamente. Os dois SAL foram misturados. Duas cabras foram inoculados, com 3ml da mistura desses SAL, associados a 2ml de adjuvante de Freund. As doses de reforço com 5 ml do SAL foram iniciadas 2 semanas após. A cabra A recebeu 8 doses (1,4 de globulinas). A cabra B recebeu 4 doses de reforço (0,7g de globulinas). Uma semana após a última inoculação retirou-se 125ml de sangue de cada cabra, fazendo a separação dos anti-soro anti SAL (ASAL). Uma terceira cabra C foi imunizada com soro normal de coelho. A determinação de precipitinas foi feita eplo método de OUCHTERLONY.O ASAL A teve título de 1:64 e B e C título de 1:128. Os ASAL A e B foram capazes de bloquear "in vitro" a atividade citotóxica do SAL até a diluição de 1:2 do SAL. O soro de cabra anti-soro normal de coelho (SCANC) nõ foi capaz de bloquear a toxicidade do SAL. Os animais submetidos a transplante cardíaco foram divididos em 2 grupos controles um normal com 10 ratos (C1) e outro (C2) com 5 ratos que recebeu 1,0ml endovenoso de SCANC. O grupo de ratos testes A foi composto de 19 ratos distribuídos em subgrupos. Subgrupo A1 com 5 ratos recebeu 0,5ml do ASAL A, via endovenosa....

Three-cell interactions in T cell-mediated suppression? A mathematical analysis of its quantitative implications.

Aiming to further our understanding of T cell-mediated suppression, we investigate the plausibility of the hypothesis that regulatory T cells suppress other T cells (target cells), while both cells are conjugated with one APC. We use a mathematical model to analyze the proliferation inhibition scored during in vitro suppression assays. This model is a radical simplification of cell culture reality, assuming that thymidine incorporation is proportional to the number of target cells that would instantaneously form conjugates with APCs that are free of regulatory cells. According to this model the inhibition index should be mainly determined by the number of regulatory cells per APC and should be insensitive to the number of target cells. We reanalyzed several published data sets, confirming this expectation. Furthermore, we demonstrate that the instantaneous inhibition index has an absolute limit as a function of the number of regulatory cells per APC. By calculating this limit we find that the model can explain the data under two non-mutually exclusive conditions. First, only approximately 15% of APCs used in the suppression assays form conjugates with T cells. Second, the growth of the regulatory cell population depends on the target cells, such that the number of regulatory cells per APC increases when they are cocultured with target cells and overcomes its limit. However, if neither of these testable conditions is fulfilled, then one could conclude that suppression in vitro does not require the formation of multicellular conjugates.

Viabilidad de fibroblastos gingivales humanos expuestos a nuevos sistemas de adhesión / Viability of human gingival fibroblasts exposed to new bonding systems

El fin de esta investigación fue conocer el efecto de 4 sistemas adhesivos: Single Bond (3M), Prime&Bond (Dentsply), Primer Vitremer (3M) y Scothbond Multiporpósito Plus (3M), sobre la viabilidad celular como marcador citotóxico de fibroblastos gingivales humanos in vitro, que permite determinar cuál de ellos puede generar una menor respuesta celular citotóxica y que sugiera un uso más adecuado en la clínica. Se utilizaron fibroblastos gingivales humanos en cuarto pase y, una vez que alcanzaron confluencia celular, se procedió a incubar en la estufa de CO2. Posteriormente, se realizaron los conteos de viabilidad celular cada 3, 6, 9 y 12 horas en el microscopio de luz. Se encontró que Single Bond, Primer Vitremer y Scotchbond Multipropósito Plus presentaron un mejor comportamiento con respecto al Prime&Bond, el cual mostró una mayor citotoxicidad

Discrimination between NK and LAK cytotoxic activities of murine spleen cells by MTT assay: differential inhibition by PGE(2) and EDTA.

In the present study we propose a mathematical approach to improve the analysis of NK and LAK activities measured by MTT assay adapted for murine cells. We found that to calculate NK activity, high E:T ratios should be used (up to 50:1) and the phenomenon fits to a linear least-squares analysis. However, 5-fold less effector cells (10:1, E:T) should be used to detect LAK activity and the phenomenon has a nonlinear exponential behavior. Using this approach, we showed that EDTA inhibits LAK but not NK activity whereas PGE(2) inhibits NK but not LAK activity. In conclusion, this analytical approach allowed the discrimination between NK and LAK activities and exposed differences between these two cytotoxic activities.

Anamnesis y prueba cutánea para prevenir reacciones fatales por medios de contraste yodados / Anamnesis and the tests of intradermorreaction for prevention of serious reactions the yodate contrast media

Antecedentes: El fenómeno de reacción alérgica y tóxica a los medios de contraste yodados ocurre con mayor frecuencia de lo que registra la literatura. Por este motivo se efectuó el presente estudio. Material y método: en un lapso de 29 años se estudiaron 178,439 casos de pacientes expuestos a medios de contraste yodado; de éstos 137,147 fueron pacientes a quienes se hizo una urografía excretora y a 41,292 una colangiografía. Se realizó un interrogatorio directo que hizo hincapié en los antecedentes personales de alergia a medios de contraste, uso de productos yodados, enfermedades del sistema nervioso y cardiovascular. Se aplicó la prueba cutánea de medios de contraste yodado. Si el resultado fue positivo no se efectuó estudio alguno con medios de contraste yodado o se hizo con medidas especiales. Resultados: se encontraron 4,302 casos positivos y 1,276 falsos negativos. Se premedicaron 287 casos positivos y se administraron medicamentos preventivos cuando hubo antecedentes de urticaria, asma o angioedema con prueba cutánea negativa. No se registraron casos de muerte. Conclusiones: los medios de contraste yodados son susceptibles de desencadenar reacciones adversas de tipo farmacológico o inmunológico. Por esta razón se destaca la utilidad de la anamnesis y las pruebas de intradermorreacción para detectar casos de reacción grave.

Diarrea asociada a clostridium difficile: evaluación de varios métodos de diagnóstico / Diarrhea associated to clostridium difficile: evaluation of several diagnostic methods

Clostridium difficile es el principal patógeno asociado a diarrea por uso de antibióticos y/o colitis psedomembranosa en pacientes hospitalizados. El diagnóstico se basa en la sospecha clínica y presencia de un test de laboratorio positivo para la detección de toxina de C. difficile, considerándose como confirmatorio el test de citotoxicidad. Recientemente se han introducido varios inmunoensayos que permiten el diagnóstico rápido; sin embargo, presentan sencibilidad y especificidad variables por lo que requiere ser evaluados por el método de referencia. El objetivo de este trabajo fue evaluar la correlación entre cinco inmunoensayos y el test confirmatorio de citotoxicidad. Para esto se estudiaron las muestras de deposiciones de 60 pacientes hospitalizados con sospecha clínica de diarrea por C. difficile mediante 4 inmunoensayos: 3 ELISA (ToxA Meridian©, Tox A Becton Dickinson© y Tox A + B TechLab© y 1 ensayo inmunocromatográfico tipo tarjeta: Inmunocard Tox A Meridian©. Cuarenta y seis muestras de las 60 se evaluaron por un test tipo tarjeta de reciente introducción: C. difficile ToxA Oxoid©. Como test confirmatorio se consideró el test de citotoxicidad. La sencibilidad fueron respectivamente: para ToxA Meridian© 95,7 y 78.8 por ciento, Tox A Becton Dickinson© 100 y 94,4 por ciento, Tox A + B TechLab© 91.3 y 86,5 por ciento. Inmunocard Tox A Meridian© 87 y 94,6 por ciento y C. difficile ToxA Oxoid© 94,7 y 96,3 por ciento. De acuerdo a los resultados, los test más recomendables serían Tox A Becton Dickinson© y C. difficile ToxA Oxoid©. Según el equipamiento y requerimientos de tiempos de respuestas de cada laboratorio, se debe establecer el tipo de inmunoensayo a utilizar

Métodos de cuantificación de la actividad citotóxica natural: un estudio comparativo / Quantitation methods of the natural killer cell activity: A comparative study

Las unidades líticas constituyen en la actualidad una de las formas más usadas de cuantificación de la actividad citotóxica natural. En el presente trabajo se utilizaron represiones lineales y no lineales propuestas en la literatura para el cálculo de éstas, con el objetivo de comparar el comportamiento de dichos modelos. Fueron ajustadas ecuaciones de regresión lineal de: a) por ciento de cromo desprendido vs la cantidad de células electoras, b) por ciento de cromo desprendido vs el logaritmo de la cantidad de células efectoras y c) arcoseno de la raíz cuadrada de la proporción de cromo desprendido vs la cantidad de células efectoras; así como una ecuación no lineal de la forma Y = A* [1/exp(/k*x)], donde Y es el por ciento de Cr desprendido. A la lisis máxima experimental, x la proporción efectoras-diana y K la pendiente de la recta que se obtiene al plotear In(A-Y) vx x. Los modelos fueron comparados desde un punto de vista estadístico, se utilizaron indicadores de bondad de ajuste, prueba de significación de la regresión para las ecuaciones lineales y porcentajes de variación explicados por los modelos, así como desde un punto de vista biológico a partir de su adecuación al fenómeno en estudio. El modelo de regresión no lineal usuado mostró ventajas apreciables en este sentido(AU)

Metodos de cuantificacion de la actividad citotoxica natural: un estudio comparativo / Quantitation methods of the natural killer cell activity: a comparative study

Las unidades liticas constituyen en la actualidad una de las formas mas usadas de cuantificacion de la actividad citotoxica natural. En el presente trabajo se utilizaron represiones lineales y no lineales propuestas en la literatura para el calculo de estas, con el objetivo de comparar el comportamiento de dichos modelos. Fueron ajustadas ecuaciones de regresion lineal de: a) por ciento de cromo desprendido vs la cantidad de celulas electoras, b) por ciento de cromo desprendido vs el logaritmo de la cantidad de celulas efectoras y c) arcoseno de la raiz cuadrada de la proporcion de cromo desprendido vs la cantidad de celulas efectoras; asi como una ecuacion no lineal de la forma Y = A* [1/exp(/k*x)], donde Y es el por ciento de Cr desprendido. A la lisis maxima experimental, x la proporcion efectoras-diana y K la pendiente de la recta que se obtiene al plotear In(A-Y) vx x. Los modelos fueron comparados desde un punto de vista estadistico, se utilizaron indicadores de bondad de ajuste, prueba de significacion de la regresion para las ecuaciones lineales y porcentajes de variacion explicados por los modelos, asi como desde un punto de vista biologico a partir de su adecuacion al fenomeno en estudio. El modelo de regresion no lineal usuado mostro ventajas apreciables en este sentido