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Tracking cell death in vivo can enable a better understanding of the biological mechanisms underlying tissue homeostasis and disease. Unfortunately, existing cell death labeling methods lack compatibility with in vivo applications or suffer from low sensitivity, poor tissue penetration, and limited temporal resolution. Here, we fluorescently labeled dead cells in vivo with Trypan Blue (TBlue) to detect single scattered dead cells or to generate whole-mount three-dimensional maps of large areas of necrotic tissue during organ regeneration. TBlue effectively marked different types of cell death, including necrosis induced by CCl4 intoxication in the liver, necrosis caused by ischemia-reperfusion in the skin, and apoptosis triggered by BAX overexpression in hepatocytes. Moreover, due to its short circulating lifespan in blood, TBlue labeling allowed in vivo "pulse and chase" tracking of two temporally spaced populations of dying hepatocytes in regenerating mouse livers. Additionally, upon treatment with cisplatin, TBlue labeled dead cancer cells in livers with cholangiocarcinoma and dead thymocytes due to chemotherapy-induced toxicity, showcasing its utility in assessing anticancer therapies in preclinical models. Thus, TBlue is a sensitive and selective cell death marker for in vivo applications, facilitating the understanding of the fundamental role of cell death in normal biological processes and its implications in disease.

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Brilliant blue 0.05% and trypan blue 0.1% were mixed in a proportion of 1:1 in a 1-mL syringe. This combination produced a waterfall effect with the fast sinking of the dye to the posterior pole and little diffusion through the vitreous cavity. Therefore, it can effectively stain the internal limiting membrane and the epiretinal membrane with a good contrast during surgeries for a macular hole, myopic foveoschisis, and macular pucker.

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The organophosphate insecticide chlorpyrifos (CPF), an acetylcholinesterase inhibitor, has raised serious concerns about human safety. Apart from inducing synaptic acetylcholine accumulation, CPF could also act at nicotinic acetylcholine receptors, like the α7-isoform (α7-nAChR), which could potentially be harmful to developing brains. Our aims were to use molecular docking to assess the binding interactions between CPF and α7-nAChR through, to test the neurocytotoxic and oxidative effects of very low concentrations of CPF on SH-SY5Y cells, and to hypothesize about the potential mediation of α7-nAChR. Docking analysis showed a significant binding affinity of CPH for the E fragment of the α7-nAChR (ΔGibbs: -5.63 to -6.85 Kcal/mol). According to the MTT- and Trypan Blue-based viability assays, commercial CPF showed concentration- and time-dependent neurotoxic effects at a concentration range (2.5-20 µM), ten-folds lower than those reported to have crucial effects for sheer CPF. A rise of the production of radical oxygen species (ROS) was seen at even lower concentrations (1-2.5 µM) of CPF after 24h. Notably, our docking analysis supports the antagonistic actions of CPF on α7-nAChR that were recently published. In conclusion, while α7-nAChR is responsible for neuronal survival and neurodevelopmental processes, its activity may also mediate the neurotoxicity of CPF.

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This work investigated the safety of extracts obtained from plants growing in Colombia, which have previously shown UV-filter/antigenotoxic properties. The compounds in plant extracts obtained by the supercritical fluid (CO2) extraction method were identified using gas chromatography coupled to mass spectrometry (GC/MS) analysis. Cytotoxicity measured as cytotoxic concentration 50% (CC50) and genotoxicity of the plant extracts and some compounds were studied in human fibroblasts using the trypan blue exclusion assay and the Comet assay, respectively. The extracts from Pipper eriopodon and Salvia aratocensis species and the compound trans-ß-caryophyllene were clearly cytotoxic to human fibroblasts. Conversely, Achyrocline satureioides, Chromolaena pellia, and Lippia origanoides extracts were relatively less cytotoxic with CC50 values of 173, 184, and 89 µg/mL, respectively. The C. pellia and L. origanoides extracts produced some degree of DNA breaks at cytotoxic concentrations. The cytotoxicity of the studied compounds was as follows, with lower CC50 values representing the most cytotoxic compounds: resveratrol (91 µM) > pinocembrin (144 µM) > quercetin (222 µM) > titanium dioxide (704 µM). Quercetin was unique among the compounds assayed in being genotoxic to human fibroblasts. Our work indicates that phytochemicals can be cytotoxic and genotoxic, demonstrating the need to establish safe concentrations of these extracts for their potential use in cosmetics.

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Direct microscopic examination of samples using potassium hydroxide (KOH) is a fast, simple, and inexpensive method to confirm clinical suspicion of superficial mycosis. However, the lack of color contrast in this test makes it difficult to separate any fungal structures from artifacts. The sensitivity of the KOH mount technique may be enhanced using both fluorochromes and conventional stains that highlight the fungal structures when observed under fluorescence microscopy and bright-field, respectively. Here we study the possibility of using Trypan Blue (TB), an azo dye which is often used as a live/dead marker, in the diagnosis of superficial mycoses by KOH testing. TB at 0.01% displayed a fluorescent staining pattern similar to that of Calcofluor White (CFW), the conventional cell wall fluorophore. Furthermore, by adjusting the TB concentration to 0.1-0.3%, in addition to maintaining the fluorescent staining pattern, the fungal elements were stained in blue under bright-field microscopy. Thus, we demonstrate for the first time that TB has the unique property as a fungal stain that can be used in both bright-field and fluorescence microscopy for diagnosis of superficial mycoses by direct microscopic examination.

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Toxocara spp. are responsible for causing toxocariasis, a zoonotic disease of global significance. In some countries of South America, toxocariasis is considered the most prevalent human helminthic infection. The objective of this study was to evaluate LIVE/DEAD® Viability/Cytotoxicity kit as an alternative method to analyze the viability of Toxacara cati larvae. Two control groups were used to confirm the usage of this methodology: 100 untreated T. cati larvae as a negative control (G1) and 100 T. cati larvae killed by thermal shock as a positive control (G2). Subsequently, the viability of T. cati larvae was assessed by the exclusion of the trypan blue dye and by LIVE/DEAD® Viability/Cytotoxicity kit, as well as observation of motility and morphology. In order to confirm the larvicidal effect, T. cati larvae G1 and G2 were inoculated in mice to evaluate their progression in vivo. As expected, G1 showed negative staining by Trypan blue and was stained green by LIVE/DEAD® Viability/Cytotoxicity kit in all the exposure periods. Moreover, G1 presented 100% of relative motility (RM) (score of 5). G2 group was stained blue by Trypan blue and red by LIVE/DEAD® Viability/Cytotoxicity kit, and had 0% RM (score zero) in 24 h of incubation period. In mice, G2 was not viable and, therefore, was not able to infect the animals. In mice inoculated with G1, however, larvae were recovered from all the evaluated organs, except eyes. These results demonstrate that the viability of T. cati larvae was accurately obtained by the LIVE/DEAD® Viability/Cytotoxicity kit, making it an alternative method for viability evaluation.

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The morpho-functional nature of the plasma membrane assists to transport nutrients into the interior of spermatozoa, which requires the physical integrity of the membrane. This present study aims to compare three different dyes used to determine the integrity of the plasma membrane of bovine spermatozoa after freezing. The dyes tested were eosin 3% (p/v), trypan blue 0.4% (p/v), and propidium iodide (1.5 mM). Two sample groups were formed for the research. In the first group, one ejaculate was collected from each 11 animals, and in the second group, ten ejaculates were obtained from one animal. The fresh semen was evaluated using microscopy. The post-freezing samples were assessed using microscopy and flow cytometry. The results are presented in the form of average viability percentages ± standard deviations. The values membrane integrity, for the dyes eosin, trypan blue, and propidium iodide were 56.8±8.3%; 56.1±7.9%; 54.6±9.1%; respectively. There were no significant differences between the groups (p≥0.001). In comparative analysis of the techniques, flow cytometry enabled a greater number of cell evaluations, compared to phase contrast microscopy, with less variability and faster sample evaluation, hence adding value to the microscopy tests.

O aspecto morfo-funcional da membrana plasmática facilita o transporte de nutrientes para o interior do espermatozoide, o que está ligado à integridade física da membrana plasmática. O presente trabalho objetivou comparar três diferentes corantes na avaliação da integridade física da membrana plasmática do espermatozoide bovino, pós-congelamento. Utilizando os corantes eosina 3% (p/v), azul de tripan 0,4% (p/v) e iodeto de propídio (1,5mM). Foram formados dois grupos para pesquisa. O primeiro, um ejaculado de cada 11 animais e um segundo grupo de dez ejaculados de um único animal. Foi realizada avaliação microscópica do sêmen fresco (motilidade total, motilidade progressiva, vigor e integridade da membrana plasmática). Das amostras congeladas foram avaliados todos os parâmetros descritos anteriormente, além da técnica de eosina, azul de tripan, e iodeto de propídio. Os resultados estão apresentados como média de porcentagem ± desvio padrão. Os valores para a integridade de membrana, utilizando os corantes eosina, azul de tripan, e iodeto de propídio, foram 56.8±8.3%; 56.1±7.9%; 54.6±9.1%, respectivamente. Não há diferença significativa entre os grupos (p≥0.001). Na análise comparativa das técnicas podemos observar que a citometria de fluxo, possibilita um número maior de avaliação celular, quando comparado à técnica de microscopia de campo claro, possibilitando uma menor variabilidade e maior rapidez na avaliação da amostra.

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The morpho-functional nature of the plasma membrane assists to transport nutrients into the interior of spermatozoa, which requires the physical integrity of the membrane. This present study aims to compare three different dyes used to determine the integrity of the plasma membrane of bovine spermatozoa after freezing. The dyes tested were eosin 3% (p/v), trypan blue 0.4% (p/v), and propidium iodide (1.5 mM). Two sample groups were formed for the research. In the first group, one ejaculate was collected from each 11 animals, and in the second group, ten ejaculates were obtained from one animal. The fresh semen was evaluated using microscopy. The post-freezing samples were assessed using microscopy and flow cytometry. The results are presented in the form of average viability percentages ± standard deviations. The values membrane integrity, for the dyes eosin, trypan blue, and propidium iodide were 56.8±8.3%; 56.1±7.9%; 54.6±9.1%; respectively. There were no significant differences between the groups (p≥0.001). In comparative analysis of the techniques, flow cytometry enabled a greater number of cell evaluations, compared to phase contrast microscopy, with less variability and faster sample evaluation, hence adding value to the microscopy tests.(AU)

O aspecto morfo-funcional da membrana plasmática facilita o transporte de nutrientes para o interior do espermatozoide, o que está ligado à integridade física da membrana plasmática. O presente trabalho objetivou comparar três diferentes corantes na avaliação da integridade física da membrana plasmática do espermatozoide bovino, pós-congelamento. Utilizando os corantes eosina 3% (p/v), azul de tripan 0,4% (p/v) e iodeto de propídio (1,5mM). Foram formados dois grupos para pesquisa. O primeiro, um ejaculado de cada 11 animais e um segundo grupo de dez ejaculados de um único animal. Foi realizada avaliação microscópica do sêmen fresco (motilidade total, motilidade progressiva, vigor e integridade da membrana plasmática). Das amostras congeladas foram avaliados todos os parâmetros descritos anteriormente, além da técnica de eosina, azul de tripan, e iodeto de propídio. Os resultados estão apresentados como média de porcentagem ± desvio padrão. Os valores para a integridade de membrana, utilizando os corantes eosina, azul de tripan, e iodeto de propídio, foram 56.8±8.3%; 56.1±7.9%; 54.6±9.1%, respectivamente. Não há diferença significativa entre os grupos (p≥0.001). Na análise comparativa das técnicas podemos observar que a citometria de fluxo, possibilita um número maior de avaliação celular, quando comparado à técnica de microscopia de campo claro, possibilitando uma menor variabilidade e maior rapidez na avaliação da amostra.(AU)

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Atualmente, a cápsula anterior e o epitélio da lente tem sido cada vez mais estudados, com o intuito de reduzir as possíveis complicações do pós-operatório da remoção da catarata, tal como a opacidade da cápsula posterior, alteração ocasionada principalmente pela diferenciação e migração das células do epitélio lenticular para a cápsula posterior da lente. O objetivo deste estudo foi analisar a composição molecular da cápsula anterior da lente pela técnica histoquímica de PAS (avaliação de proteoglicanos) e picrosirius red (avaliação de colágeno IV), em cães idosos com catarata diabética e não diabética do tipo hipermadura, submetidos ao uso ou não de azul de tripano a 0,1 % durante a facoemulsificação. Vinte e sete cães foram estudados, incluindo 21 fêmeas e 6 machos, de 8 a 12 anos de idade (média = 9,6 anos), de diversas raças e divididos em 2 grupos: GC (catarata hipermadura) e GCD (catarata diabética). Os resultados das análises realizadas mostraram que ambas as amostras, tanto as provenientes das cataratas hipermaduras, quanto das diabéticas, apresentam semelhante composição molecular de proteoglicanos e colágeno IV e isto independente da utilização de azul de tripano a 0,1 %. Conclui-se, portanto, que se os resultados obtidos forem decorrentes de alterações provocadas pelo rápido metabolismo da catarata diabética e pela cronicidade da catarata hipermadura sugere-se que o comprometimento da estrutura capsular seja de intensidade equivalente e, por consequência, que isto também possa prejudicar o metabolismo das células do epitélio anterior da lente, diminuindo assim a incidência da opacidade da cápsula posterior de cães com catarata diabética e hipermadura submetidos à facoemulsificação.(AU)

Nowadays, the anterior lens capsule and its epithelium have been being frequently studied aiming to reduce the incidence of posterior lens capsule opacity, a complication that frequently occurs after surgical removal of cataracts, due to epithelium cells differentiation and migration to the posterior pole. The objective of this study was to evaluate by histochemistry (PAS and picrosirius red) analysis two important molecular components of the anterior lens capsule (proteoglycans and type IV collagen) in older diabetic and non-diabetic dogs, with diabetic and hypermature cataracts, after phacoemulsification surgery utilizing 0.1% trypan blue or not. Twenty seven dogs, including 21 female and 6 male dogs, with ages varying from 8 to 12 years old (mean = 9.6 yo) of different breeds were studied. The animals were divided into 2 groups: GC (hypermature cataracts) and GCD (diabetic cataracts). Results showed that, besides their different pathophysiologies, both types of capsules studied (diabetic and hypermature ones) presented the same molecular composition of proteoglycans and type IV collagen, since no statistical significant differences were observed. In addition, 0.1% trypan blue was not capable to induce any other evident alteration for the samples. In conclusion, our findings suggest that, if the results consist in alteration induced by the aggressive metabolism of the diabetic cataract or the chronicity of the hypermature one, it is of the same intensity and independent of the use of 0.1% trypan blue. It is also possible to suggest that this alteration must be capable to compromise lens epithelium cell metabolism, which should probably favour future lens posterior capsule studies.(AU)

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Atualmente, a cápsula anterior e o epitélio da lente tem sido cada vez mais estudados, com o intuito de reduzir as possíveis complicações do pós-operatório da remoção da catarata, tal como a opacidade da cápsula posterior, alteração ocasionada principalmente pela diferenciação e migração das células do epitélio lenticular para a cápsula posterior da lente. O objetivo deste estudo foi analisar a composição molecular da cápsula anterior da lente pela técnica histoquímica de PAS (avaliação de proteoglicanos) e picrosirius red (avaliação de colágeno IV), em cães idosos com catarata diabética e não diabética do tipo hipermadura, submetidos ao uso ou não de azul de tripano a 0,1 % durante a facoemulsificação. Vinte e sete cães foram estudados, incluindo 21 fêmeas e 6 machos, de 8 a 12 anos de idade (média = 9,6 anos), de diversas raças e divididos em 2 grupos: GC (catarata hipermadura) e GCD (catarata diabética). Os resultados das análises realizadas mostraram que ambas as amostras, tanto as provenientes das cataratas hipermaduras, quanto das diabéticas, apresentam semelhante composição molecular de proteoglicanos e colágeno IV e isto independente da utilização de azul de tripano a 0,1 %. Conclui-se, portanto, que se os resultados obtidos forem decorrentes de alterações provocadas pelo rápido metabolismo da catarata diabética e pela cronicidade da catarata hipermadura sugere-se que o comprometimento da estrutura capsular seja de intensidade equivalente e, por consequência, que isto também possa prejudicar o metabolismo das células do epitélio anterior da lente, diminuindo assim a incidência da opacidade da cápsula posterior de cães com catarata diabética e hipermadura submetidos à facoemulsificação.(AU)

Nowadays, the anterior lens capsule and its epithelium have been being frequently studied aiming to reduce the incidence of posterior lens capsule opacity, a complication that frequently occurs after surgical removal of cataracts, due to epithelium cells differentiation and migration to the posterior pole. The objective of this study was to evaluate by histochemistry (PAS and picrosirius red) analysis two important molecular components of the anterior lens capsule (proteoglycans and type IV collagen) in older diabetic and non-diabetic dogs, with diabetic and hypermature cataracts, after phacoemulsification surgery utilizing 0.1% trypan blue or not. Twenty seven dogs, including 21 female and 6 male dogs, with ages varying from 8 to 12 years old (mean = 9.6 yo) of different breeds were studied. The animals were divided into 2 groups: GC (hypermature cataracts) and GCD (diabetic cataracts). Results showed that, besides their different pathophysiologies, both types of capsules studied (diabetic and hypermature ones) presented the same molecular composition of proteoglycans and type IV collagen, since no statistical significant differences were observed. In addition, 0.1% trypan blue was not capable to induce any other evident alteration for the samples. In conclusion, our findings suggest that, if the results consist in alteration induced by the aggressive metabolism of the diabetic cataract or the chronicity of the hypermature one, it is of the same intensity and independent of the use of 0.1% trypan blue. It is also possible to suggest that this alteration must be capable to compromise lens epithelium cell metabolism, which should probably favour future lens posterior capsule studies.(AU)

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Atualmente, a cápsula anterior e o epitélio da lente tem sido cada vez mais estudados, com o intuito de reduzir as possíveis complicações do pós-operatório da remoção da catarata, tal como a opacidade da cápsula posterior, alteração ocasionada principalmente pela diferenciação e migração das células do epitélio lenticular para a cápsula posterior da lente. O objetivo deste estudo foi analisar a composição molecular da cápsula anterior da lente pela técnica histoquímica de PAS (avaliação de proteoglicanos) e picrosirius red (avaliação de colágeno IV), em cães idosos com catarata diabética e não diabética do tipo hipermadura, submetidos ao uso ou não de azul de tripano a 0,1 % durante a facoemulsificação. Vinte e sete cães foram estudados, incluindo 21 fêmeas e 6 machos, de 8 a 12 anos de idade (média = 9,6 anos), de diversas raças e divididos em 2 grupos: GC (catarata hipermadura) e GCD (catarata diabética). Os resultados das análises realizadas mostraram que ambas as amostras, tanto as provenientes das cataratas hipermaduras, quanto das diabéticas, apresentam semelhante composição molecular de proteoglicanos e colágeno IV e isto independente da utilização de azul de tripano a 0,1 %. Conclui-se, portanto, que se os resultados obtidos forem decorrentes de alterações provocadas pelo rápido metabolismo da catarata diabética e pela cronicidade da catarata hipermadura sugere-se que o comprometimento da estrutura capsular seja de intensidade equivalente e, por consequência, que isto também possa prejudicar o metabolismo das células do epitélio anterior da lente, diminuindo assim a incidência da opacidade da cápsula posterior de cães com catarata diabética e hipermadura submetidos à facoemulsificação.

Nowadays, the anterior lens capsule and its epithelium have been being frequently studied aiming to reduce the incidence of posterior lens capsule opacity, a complication that frequently occurs after surgical removal of cataracts, due to epithelium cells differentiation and migration to the posterior pole. The objective of this study was to evaluate by histochemistry (PAS and picrosirius red) analysis two important molecular components of the anterior lens capsule (proteoglycans and type IV collagen) in older diabetic and non-diabetic dogs, with diabetic and hypermature cataracts, after phacoemulsification surgery utilizing 0.1% trypan blue or not. Twenty seven dogs, including 21 female and 6 male dogs, with ages varying from 8 to 12 years old (mean = 9.6 yo) of different breeds were studied. The animals were divided into 2 groups: GC (hypermature cataracts) and GCD (diabetic cataracts). Results showed that, besides their different pathophysiologies, both types of capsules studied (diabetic and hypermature ones) presented the same molecular composition of proteoglycans and type IV collagen, since no statistical significant differences were observed. In addition, 0.1% trypan blue was not capable to induce any other evident alteration for the samples. In conclusion, our findings suggest that, if the results consist in alteration induced by the aggressive metabolism of the diabetic cataract or the chronicity of the hypermature one, it is of the same intensity and independent of the use of 0.1% trypan blue. It is also possible to suggest that this alteration must be capable to compromise lens epithelium cell metabolism, which should probably favour future lens posterior capsule studies.

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Background: Medicinal plants are widely used to treat infectious diseases, metabolic disorders and cancer. Argemone mexicana L. (A. mexicana), commonly found on desolate land of Marathwada (Maharashtra, India) has been used to treat oral cavity infections. Methods: In this study, cold aqueous and methanolic extracts were prepared from A. mexicana stem and leaves. These extracts were tested for their antifungal and anticancer activities. The antifungal activity was tested using the agar well diffusion method, while the anticancer activity against immortalized cell lines was assessed by trypan blue assay. Results: It was observed that both cold aqueous and methanolic extracts of A. mexicana stem and leaves inhibited the growth of Mucor indicus, Aspergillus flavus, Aspergillus niger and Penicillum notatum. Antifungal activity of the extract was comparable to that of Amphoterecin-B. A. mexicana extracts had a cytotoxic effect on A549, SiHa and KB immortalized cell lines that were similar to that of berberine. Conclusion: The A. mexicana leaf and stems exhibit strong antifungal and anticancer potential.

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Several laboratory methods to evaluate ram sperm quality have been developed. The combination of different fluorescent probes is suitable to simultaneously evaluate different sperm characteristics but the need fora fluorescent microscope restricts its use. The Aim of the present study was to evaluate the efficacy of Hypoosmotic Trypan Blue Giemsa (HTBG) staining to simultaneously detect sperm morphological abnormalities, plasma and acrosomal membrane integrity using phase contrast and fluorescence microscopy as the gold standards. Samples from twelve fresh ejaculates from three rams (4 ejaculates/ram) were used in the study. Sperm cells were evaluated using HTBG, phase contrast (PC) and fluorescent (FLUO) techniques. HTBG was more effective in detecting sperm defects when compared to PC (P 0.05) were observed between HTBG and FLUO in the assessment of plasmatic membrane and acrosome integrity. High correlation between HTBG and FLUO techniques was observed when assessing plasma membrane and acrosome (R = 0.97 and 0.96, respectively). In conclusion, the HTBG staining is suitable to assess ram sperm morphology, plasma and acrossomal membrane integrity simultaneously.

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Several laboratory methods to evaluate ram sperm quality have been developed. The combination of different fluorescent probes is suitable to simultaneously evaluate different sperm characteristics but the need fora fluorescent microscope restricts its use. The Aim of the present study was to evaluate the efficacy of Hypoosmotic Trypan Blue Giemsa (HTBG) staining to simultaneously detect sperm morphological abnormalities, plasma and acrosomal membrane integrity using phase contrast and fluorescence microscopy as the gold standards. Samples from twelve fresh ejaculates from three rams (4 ejaculates/ram) were used in the study. Sperm cells were evaluated using HTBG, phase contrast (PC) and fluorescent (FLUO) techniques. HTBG was more effective in detecting sperm defects when compared to PC (P < 0.05). No significant differences (P > 0.05) were observed between HTBG and FLUO in the assessment of plasmatic membrane and acrosome integrity. High correlation between HTBG and FLUO techniques was observed when assessing plasma membrane and acrosome (R = 0.97 and 0.96, respectively). In conclusion, the HTBG staining is suitable to assess ram sperm morphology, plasma and acrossomal membrane integrity simultaneously.(AU)

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La investigación ha demostrado que existe un aumento em la viabilidad celular cuando se produce un aumento en el conteo de células somáticas (CCS) en infecciones de la glándula mamaria en animales. El principal microorganismo aislado en la mastitis subclínica en el ganado caprino es Staphylococcus spp. Los objetivos de este estúdio son determinar el CCS, células viables y relacionar los con Staphylococcus spp. aislado de las muestras de leche de cabras con mastitis subclínica. Se cosecharon três alícuotas de las muestras de leche de cabras reactivas para CMT (CaliforniaMastitis Test) para la realización de la viabilidad celular, la microbiología y de CCS. Se determino la viabilidad de las células después de la centrifugación de las muestras de leche y la visualización de las células bajo un microscópio, utilizando colorante azul de Trypan, y la cantidad de CCS a través del equipo de citometría de flujo. De las muestras, 104 no estaban aislando microorganismos y 110 mostraron aislamiento de Staphylococcus spp., de los cuales el detectado con mayor frecuencia fueron: S. epidermidis, S. intermedius y S. lugdunensis. Hubo una diferencia estadísticamente significativa entre el CCS y la viabilidad celular de las muestras en las que no había aislamiento de Staphylococcus spp. y muestras sin crecimiento bacteriano, que mostraron un aumento en CCS y la viabilidad celular en las muestras de leche de cabras con mastitis subclínica causada por Staphylococcus spp.(AU)

Research has shown that there is an increase in cell viability when a growth in somatic cell count (SCC) in infections of the mammary gland occurs. The main microorganism isolated from subclinical mastitis in goats is Staphylococcus spp. The aims of this study were determined SCC, viable cells and relate them with Staphylococcus spp. isolated from milk samples of goats with subclinical mastitis. Three aliquots of milk samples from goats reagents to CMT test (California Mastitis Test) were collected for performing cell viability, microbiology and SCC. Cell viability, after centrifugation of milk samples and viewing the cells under a microscope, using Trypan blue dye, and the amount of SCC, through the flow cytometry equipment, were determinated. A total of 104 samples had no isolation of microorganisms and 110 showed isolation of Staphylococcusspp., of which the most frequently detected were: S. epidermidis, S. intermedius and S. lugdunensis. There was a statistically significant difference between SCC and cell viability of samples in which there was isolation of Staphylococcus spp. and samples without bacterial growth, that showed an increase in SCC and cell viability in milk samples of goats with subclinical mastitis caused by Staphylococcus spp.(AU)

Pesquisas têm demonstrado que há uma elevação na viabilidade celular quando ocorre aumento na contagem de células somáticas (CCS) em infecções da glândula mamária em animais. O principal micro-organismo isolado em mastite subclínica dos caprinos é Staphylococcus spp. Os objetivos do presente estudo foram determinar a CCS, células viáveis e relacioná-las com Staphylococcus spp. isolados de amostras de leite de cabras com mastite subclínica. Foram colhidas três alíquotas de amostras de leite de cabras reagentes ao teste do CMT (CaliforniaMastitis Test) para a realização da viabilidade celular, exame microbiológico e CCS. Determinou-se a viabilidade celular, após centrifugações das amostras de leite e visualização das células em microscópio, utilizando o corante azul de Trypan e a quantidade de CCS, utilizando equipamento de citometria de fluxo. Das amostras analisadas, 104 não tiveram isolamento de micro-organismos e 110 apresentaram isolamento de Staphylococcus spp., dos quais os mais frequentemente detectados foram: S. epidermidis, S. intermedius e S. lugdunensis. Foi observada diferença estatisticamente significante entre a CCS e a viabilidade celular das amostras nas quais houve isolamento de Staphylococcus spp. e as amostras sem crescimento bacteriano, o que demonstrou um aumento da CCS e da viabilidade celular nas amostras de leite de cabras com mastite subclínica por Staphylococcus spp.(AU)

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INTRODUCTION: This study aims to optimize some experimental conditions of a flow cytometric assay to examine the human neutrophil ability to phagocytose immune complexes (ICs) via Fcγ and complement receptors (FcγR and CR, respectively). The parameters assessed were: number of cells, concentration of ICs, reaction time, pH and concentration of the Trypan Blue quenching solution. METHODS: Neutrophils were isolated from peripheral blood of healthy volunteers. Precipitated ICs composed of IgG and fluorescein isothiocyanate (FITC)-labeled ovalbumin, opsonized or not with serum complement, were used to trigger the neutrophil phagocytosis via FcγR, CR, and FcγR+CR. Fluorescence of the internalized ICs was measured by flow cytometry, after quenching the extracellular fluorescence with Trypan Blue. RESULTS: The optimal experimental conditions established for the phagocytosis assay were: 1 × 10(6) cells mL(-1) and 40 µg mL(-1) FITC-labeled ICs, incubated for 30 min, at 37°C, in 0.5 mL of reaction volume. Trypan Blue solution at 1.25 mg mL(-1) pH4.4 was the best fluorescence quencher of FITC-labeled ICs attached to the outer surface of neutrophils. DISCUSSION: The selected experimental conditions were viable to evaluate IC phagocytosis by neutrophils; they are also suitable to compare the efficiency of IC phagocytosis mediated by FcγR and CR classes of membrane receptors, alone or in combination. This method finds application in studies of (i) the receptor-specific phagocytic function of normal and pathogenic neutrophils as well as (ii) the impact of drugs and therapies on this essential effector function of neutrophils.

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A viable cell count is essential to evaluate the kinetics of cell growth. Since the hemocytometer was first used for counting blood cells, several variants of the methodology have been developed towards reducing the time of analysis and improving accuracy through automation of both sample preparation and counting. The successful implementation of automated techniques relies in the adjustment of cell staining, image display parameters and cell morphology to obtain equivalent precision, accuracy and linearity with respect to the hemocytometer. In this study we conducted the validation of three trypan blue exclusion-based methods: manual, semi-automated, and fully automated; which were used for the estimation of density and viability of cells employed for the biosynthesis and bioassays of recombinant proteins. Our results showed that the evaluated attributes remained within the same range for the automated methods with respect to the manual, providing an efficient alternative for analyzing a huge number of samples.

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Purpose: The present experimental study aimed to investigate the effects of intracameral trypan blue (TB) on oxidative stress parameters and apoptosis in corneal tissue. Methods: Thirty rats were randomly assigned to three groups of 10 rats each: the sham group (Group 1); control group (Group 2); and treatment group (Group 3). The control group was administered 0.01 cc of balanced salt solution. The treatment group was administered 0.006 mg/0.01 cc of TB. The total antioxidant status (TAS) and total oxidant status (TOS) in corneal tissue and blood were measured and the oxidative stress index (OSI) was calculated. Finally, corneal tissue histopathology was evaluated using staining for caspase-3 and -8, and apoptotic activity was examined. Results: The TAS, TOS and OSI levels in the blood samples were not significantly different (p>0.05 for all). Compared with the sham and control groups, the TOS and OSI levels in corneal tissue were significantly different in the treatment group (p<0.05 for all). No significant difference was observed between the sham group and the control group (p>0.05). Immunohistochemical staining for caspase-3 and caspase-8 demonstrated higher apoptotic activity in the TB group than in the sham and control groups. Conclusion: The present study showed that intracameral TB injection is safe systematically but may be toxic to corneal tissue, as demonstrated using oxidative stress parameters and histopathological evaluation. .

Objetivo: Este estudo experimental tem como objetivo investigar os efeitos do azul de tripan intracameral (TB) sobre parâmetros de estresse oxidativo e apoptose no tecido da córnea. Métodos: Trinta ratos foram divididos aleatoriamente em três grupos de 10 animais cada: grupo simulação (Grupo 1); grupo controle (Grupo 2); e grupo tratamento (Grupo 3). No grupo controle foi administrado 0,01 cc de solução salina balanceada (BSS). No grupo tratamento foi administrado 0,006 mg/0,01 cm de TB. O estado antioxidante total ( TAS) e estado oxidante total ( TOS) no tecido da córnea e sangue foram medidos e o índice de estresse oxidativo (OSI) foi calculado. Finalmente, histopatologia do tecido da córnea foi avaliada por meio da coloração para caspase-3 e -8; atividade apoptótica também foi examinada. Resultados: Os níveis de TAS, TOS e OSI das amostras de sangue não foram significativamente diferentes (p>0,05 para todos). Em comparação com os grupos simulação e controle, os níveis de TOS e OSI no tecido da córnea foram significativamente diferentes no grupo tratamento (p<0,05 para todos). Não houve diferença significativa entre o grupo simulção e o grupo controle (p>0,05). A coloração imuno-histoquímica com a caspase-3 e caspase-8 demonstrou maior atividade apoptótica no grupo tratamento do que nos grupos controle e simulação. Conclusão: Este estudo mostrou que a injeção intracameral TB é segura sistematicamente, mas pode ser tóxica ao tecido da córnea, como demonstrado através de parâmetros de estresse oxidativo e avaliação histopatológica. .

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Adequate visualization and identification of the posterior hyaloid, epiretinal membranes and the internal limiting membrane are of paramount importance in modern vitreoretinal surgery. "Chromovitrectomy" is a term used for describing the vital dyes use in order to stain these transparent tissues and facilitate their manipulation during vitreous surgery. This article reviews the indications, applications and characteristics of vital dyes in vitreoretinal surgery. Various dyes are currently being used in routine clinical procedures, however the ideal staining agent has not yet been found. Any dye which is injected intravitreally has the potential to become toxic. Triamcinolone acetonide is used to highlight the vitreous and is particularly beneficial in determining the attachment of the posterior hyaloid to the underlying retina. Trypan blue stains epiretinal membranes and facilitates their complete removal. Both indocyanine green and brilliant blue G stain the internal limiting membrane properly, however concerns over indocyanine green toxicity have made surgeons switch to brillliant blue G as a safer alternative.

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Dye exclusion tests are used to determine the number of live and dead cells. These assays are based on the principle that intact plasma membranes in live cells exclude specific dyes, whereas dead cells do not. Although widely used, the trypan blue (TB) exclusion assay has limitations. The dye can be incorporated by live cells after a short exposure time, and personal reliability, related to the expertise of the analyst, can affect the results. We propose an alternative assay for evaluating cell viability that combines the TB exclusion test and the high sensitivity of the flow cytometry technique. Previous studies have demonstrated the ability of TB to emit fluorescence when complexed with proteins. According to our results, TB/bovine serum albumin and TB/cytoplasmic protein complexes emit fluorescence at 660 nm, which is detectable by flow cytometry using a 650-nm low-pass band filter. TB at 0.002% (w/v) was defined as the optimum concentration for distinguishing unstained living cells from fluorescent dead cells, and fluorescence emission was stable for 30 min after cell treatment. Although previous studies have shown that TB promotes green fluorescence quenching, TB at 0.002% did not interfere with green fluorescence in human live T-cells stained with anti-CD3/fluorescein isothiocyanate (FITC) monoclonal antibody. We observed a high correlation between the percentage of propidium iodide+CD3/FITC+ and TB+CD3/FITC+ cells, as well as similar double-stained cell profiles in flow cytometry dot-plot graphs. Taken together, the results indicate that a TB exclusion assay by flow cytometry can be employed as an alternative tool for quick and reliable cell viability analysis.

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