Paloma Morales

Cytotoxicity and ROS production of manufactured silver nanoparticles of different sizes in hepatoma and leukemia cells

Silver nanoparticles (AgNPs), which have well‐known antimicrobial properties, are extensively used in various medical and general applications. In spite of the widespread use of AgNPs, relatively few studies have been undertaken to determine the cytotoxic effects of AgNPs. The aim of this study was investigate how AgNPs of different sizes (4.7 and 42 nm) interact with two different tumoral human cell lines (hepatoma [HepG2] and leukemia [HL‐60]). In addition, glutathione depletion, inhibition of superoxide dismutase (SOD) and reactive oxygen species (ROS) generation were used to evaluate feasible mechanisms by which AgNPs exerted its toxicity. AgNPs of 4.7 nm and 42 nm exhibited a dramatic difference in cytotoxicity. Small AgNPs were much more cytotoxic than large AgNPs. A difference in the cellular response to AgNPs was found. HepG2 cells showed a higher sensitivity to the AgNPs than HL‐60. However, the cytotoxicity induced by AgNPs was efficiently prevented by NAC treatment, which suggests that oxidative stress is primarily responsible for the cytotoxicity of AgNPs. Furthermore, cellular antioxidant status was disturbed: AgNPs exposure caused ROS production, glutathione depletion and slight, but not statistically significant inactivation of SOD. Copyright

Guía para el diagnóstico, tratamiento y seguimiento de la tromboembolia pulmonar

La tromboembolia pulmonar (TEP) es la manifestación más grave de la enfermedad tromboembólica venosa. Hasta la década de los ochenta, tanto en el diagnóstico como en el tratamiento o el seguimiento, no hubo cambios sustanciales. Sólo desde hace poco más de una década asistimos al desarrollo de múltiples herramientas que mejoran el rendimiento diagnóstico, así como a nuevas opciones terapéuticas que pueden permitir modelos distintos de manejo de la enfermedad. La Sociedad Española de Neumología y Cirugía Torácica pretende a través de esta guía establecer unas recomendaciones actualizadas que, basándose en la evidencia científica disponible, sean útiles para el diagnóstico, tratamiento y seguimiento de la TEP.

Immunostick ELISA for Detection of Cow's Milk in Ewe's Milk and Cheese Using a Monoclonal Antibody against Bovine β-Casein

An immunostick enzyme-linked immunosorbent assay (ELISA) has been developed for the rapid detection of cows milk in ewes milk or cheese. The assay uses a monoclonal antibody (AH4) produced against bovine β-casein for the detection of cows milk or cheese bound to the paddles of immunostick tubes. This immunostick ELISA allows the visual identification of ewes milk containing more than 1% of cows milk or cheese samples containing more than 0.5% of cows cheese.

Oxidative stress contributes to gold nanoparticle-induced cytotoxicity in human tumor cells

Abstract Due to their exceptional properties, gold nanoparticles (AuNPs) have shown promising medical and technological applications in the treatment of cancer and the development of antimicrobial packaging and time–temperature indicators in the food sector. However, little is known about their cytotoxicity when they come into contact with biological systems. The aim of this work was to compare the effects of three commercially available AuNPs of different sizes (30, 50 and 90 nm) on human leukemia (HL-60) and hepatoma (HepG2) cell lines. AuNP-induced cytotoxicity was dose and time-dependent, with IC50 values higher than 15 μg/mL. Nanoparticle (NP) size and cell line slightly influenced on the cytotoxicity of AuNPs, although HL-60 cells proved to be more sensitive to the cytotoxic response than HepG2. N-Acetyl-l-cysteine (NAC) protected HL-60 and HepG2 cells only against treatment with 30 nm AuNPs. In both cell types, glutathione (GSH) content was drastically depleted after 72 h of incubation with the three AuNPs (less than 30% in all cases), while the reduction of superoxide dismutase activity (SOD) activity depended on cell line. HepG2, but not HL-60 cells, exhibited a decrease of SOD activity (∼45% of activity). The three AuNPs also caused a two-fold elevation of reactive oxygen species (ROS) production in both cell lines. Thus, protective effect of NAC, depletion of GSH and increase of ROS appear to be determined by NP size and indicate that oxidative stress contributes to cytotoxicity of AuNPs.

Selective apoptotic effects of piceatannol and myricetin in human cancer cells

Numerous studies have shown the potential of dietary polyphenols as anticarcinogenic agents. The aim of the present study was to evaluate the apoptotic effects of piceatannol and myricetin, naturally occurring polyphenols in red wine, alone or in combination, in two human cell lines: HL‐60 (leukemia) and HepG2 (hepatoma). Apoptotic cells were identified by chromatin condensation, poly(ADP‐ribose) polymerase cleavage and flow cytometry analysis. Results from TUNEL assay showed that piceatannol or myricetin alone induced apoptotic cell death in a concentration‐ and time‐dependent manners in HL‐60 cells. Furthermore, in combined treatment the percentage of apoptotic HL‐60 cells was significantly higher. Nevertheless, the percentage of TUNEL positive HepG2 cells only was significant after piceatannol treatment and in combined treatment was even lower than in cells treated with piceatannol alone. Moreover, we also studied the relative reactive oxygen species (ROS) production. Our results indicate that apoptosis induced by piceatannol or myricetin occurs through an ROS‐independent cell death pathway. In conclusion, piceatannol and myricetin synergistically induced apoptosis in HL‐60 cells but not in HepG2 cells. These findings suggest that the potential anticarcinogenic properties of dietary polyphenols depend largely on the cell line used. The relevance of these data needs to be verified in human epidemiological studies. Copyright

Anti-proliferative effect of two lactic acid bacteria strains of human origin on the growth of a myeloma cell line.

Aims: Twenty lactic acid bacteria strains were isolated from human faeces and tested by MTT assay for stimulation or inhibition of the proliferation of Vero and myeloma cells.

Detection and quantification of goat's cheese in ewe's cheese using a monoclonal antibody and two ELISA formats

A stable hybridoma cell line (B2B) has been produced secreting a monoclonal antibody (MAb) specific for the s αs2-casein of goats. The MAb B2B was used in two enzyme-linked immunosorbent assays (ELISA) formats for the detection and quantification of the presence of goats cheese in ewes cheese samples. In the indirect ELISA format the limit of detection was 1–25% (w/w) substitution of ewes cheese samples by goats cheese. Afterwards, a competitive indirect ELISA was successfully developed for the detection of 0.5 to 25% (w/w) of goats cheese in ewes cheese samples. This competitive indirect ELISA is a very sensitive assay, can be performed in less than 5 h and is not influenced by the ripening process in cheese.

Use of a monoclonal antibody and two enzyme-linked immunosorbent assay formats for detection and quantification of the substitution of caprine milk for ovine milk

A stable hybridoma cell line (B2B) has been produced that secretes a monoclonal antibody (MAb) specific for goats milk αS2-casein. The MAb B2B was used in two enzyme-linked immunosorbent assay (ELISA) formats for the detection and quantification of the presence of goats milk in ewes milk. In the indirect ELISA format the limit of detection was 0.5 to 15% (vol/vol) substitution of goats milk for ewes milk. Afterwards, a competitive indirect ELISA was successfully developed for the detection of 0.25 to 15% (vol/vol) of goats milk in ewes milk. This competitive indirect ELISA is a very sensitive assay; it can be performed in less than 5 h and is not influenced by the heat treatment of milk.

Effects of (+)catechin and (−)epicatechin on heterocyclic amines‐induced oxidative DNA damage

The aim of the present study was to evaluate the protective effect of (+)‐catechin and (−)‐epicatechin against 2‐amino‐3,8‐ dimethylimidazo[4,5‐f]quinoxaline (8‐MeIQx), 2‐amino‐3,4,8‐trimethylimidazo[4,5‐f]‐quinoxaline (4,8‐diMeIQx) and 2‐amino‐1‐methyl‐6‐phenyl‐imidazo[4,5‐b]pyridine (PhIP)‐induced DNA damage in human hepatoma cells (HepG2). DNA damage (strand breaks and oxidized purines/pyrimidines) was evaluated by the alkaline single‐cell gel electrophoresis or comet assay. Increasing concentrations of 8‐MeIQx, 4,8‐diMeIQx and PhIP induced a significant increase in DNA strand breaks and oxidized purines and pyrimidines in a dose‐dependent manner. Among those, PhIP (300 µm) exerted the highest genotoxicity. (+)‐Catechin exerted protection against oxidized purines induced by 8‐MeIQx, 4,8‐diMeIQx and PhIP. Oxidized pyrimidines and DNA strand breaks induced by PhIP were also prevented by (+)‐catechin. Otherwise, (−)‐epicatechin protected against the oxidized pyrimidines induced by PhIP and the oxidized purines induced by 8‐MeIQx and 4,8‐diMeIQx. One feasible mechanism by which (+)‐catechin and (−)‐epicatechin exert their protective effect towards heterocyclic amines‐induced oxidative DNA damage may be by modulation of phase I and II enzyme activities. The ethoxyresorufin O‐deethylation (CYP1A1) activity was moderately inhibited by (+)‐catechin, while little effect was observed by (−)‐epicatechin. However, (+)‐catechin showed the greatest increase in UDP‐glucuronyltransferase activity. In conclusion, our results clearly indicate that (+)‐catechin was more efficient than (−)‐epicatechin in preventing DNA damage (strand breaks and oxidized purines/pyrimidines) induced by PhIP than that induced by 8‐MeIQx and 4,8‐diMeIQx. Copyright

Interactions of manufactured silver nanoparticles of different sizes with normal human dermal fibroblasts

Silver compounds have been used for their medicinal properties for centuries. At present, silver nanoparticles (AgNPs) are reemerging as a viable topical treatment option for infections encountered in burns, open wounds and chronic ulcers. This study evaluated the in vitro mechanisms of two different sizes of AgNPs (4·7 and 42 nm) toxicity in normal human dermal fibroblasts. The toxicity was evaluated by observing cell viability and oxidative stress parameters. In all toxicity endpoints studied (MTT and lactate dehydrogenase assays), AgNPs of 4·7 nm were much more toxic than the large AgNPs (42 nm). The cytotoxicity of both AgNPs was greatly decreased by pre‐treatment with the antioxidant N‐acetyl‐L‐cysteine. The oxidative stress parameters showed significant increase in reactive oxygen species levels, depletion of glutathione level and slight, but not statistically significant inactivation of superoxide dismutase, suggesting generation of oxidative stress. Thus, AgNPs should be used with caution for the topical treatment of burns and wounds, medical devices etc, because their toxicity depends on the size, the smaller NPs being much more cytotoxic than the large.