In vitro cytotoxicity of Selol-loaded magnetic nanocapsules against neoplastic cell lines under AC magnetic field activation

The goals of this study are to evaluate in vitro compatibility of magnetic nanomaterials and their therapeutic potential against cancer cells. Highly stable ionic magnetic fluid sample (maghemite, gamma-Fe2O3) and Selol were incorporated into polymeric nanocapsules by nanoprecipitation method. The cytotoxic effect of Selol-loaded magnetic nanocapsules was assessed on murine melanoma (B16-F10) and oral squamous cell carcinoma (OSCC) cell lines following AC magnetic field application. The influence of different nanocapsules on cell viability was investigated by colorimetric MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. In the absence of AC magnetic field Selol-loaded magnetic nanocapsules, containing 100 mu g/mL Selol plus 5 x 10(12) particle/mL, showed antitumoral activity of about 50% on B16-F10 melanoma cells while OSCC carcinoma cells demonstrated drug resistance at all concentrations of Selol and magnetic fluid (range of 100-500 mu g/mL Selol and 5 x 10(12) -2.5 x 10(13) particle/mL). On the other hand, under AC applied fields (1 MHz and 40 Oe amplitude) B16-F10 cell viability was reduced down to 40.5% (+/- 3.33) at the highest concentration of nanoencapsulated Selol. The major effect, however, was observed on OSCC cells since the cell viability drops down to about 33.3% (+/- 0.38) under application of AC magnetic field. These findings clearly indicate that the Selol-loaded magnetic nanocapsules present different toxic effects on neoplastic cell lines. Further, the cytotoxic effect was maximized under AC magnetic field application on OSCC, which emphasizes the effectiveness of the magnetohyperthermia approach. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3680541]

Protective effect of bixin on cisplatin-induced genotoxicity in PC12 cells

Bixin is the main carotenoid found in annatto seeds (Bixa orellana L.) and is responsible for their reddish-orange color. The antioxidant properties of this compound are associated with its ability to scavenge free radicals, which may reduce damage and protect tissues against toxicity caused by anticancer drugs such as cisplatin. In this study, the genotoxicity and antigenotoxicity of bixin on cisplatin-induced toxicity in PC12 cells was assessed. Cytotoxicity was evaluated using the mu assay, mutagenicity, genotoxicity, and protective effect of bixin were evaluated using the micronucleus test and comet assay. PC12 cells were treated with bixin (0.05, 0.08, and 0.10 mu g/mL), cisplatin (0.1 mu g/mL) or a combination of both bixin and cisplatin. Bixin was neither cytotoxic nor genotoxic compared to the controls. In the combined treatment bixin significantly reduced the percentage of DNA in tail and the frequency of micronuclei induced by cisplatin. This result suggests that bixin can function as a protective agent, reducing cisplatin-induced DNA damage in PC12 cells, and it is possible that this protection could also extend to neuronal cells. Further studies are being conducted to better understand the mechanisms involved in the activity of this protective agent prior to using it therapeutically. (C) 2011 Elsevier Ltd. All rights reserved.

Antigenotoxic Effects of Piquia (Caryocar villosum) in Multiple Rat Organs

This study investigated the in vivo genotoxicity of piquia pulp (Caryocar villosum) and its potential antigenotoxicity on doxorubicin (DXR)-induced DNA damage by comet assay and micronucleus test. In addition, the phytochemicals present in piquia pulp were determined. Piquia fruit pulp (75, 150 or 300 mg/kg b.w.) was administered by gavage to Wistar rats for 14 days, and the animals received an injection of saline or DXR (15 mg/kg b.w., i.p.) 24 h before they were euthanized. The phytochemical analysis revealed the presence of carotenoids; phenolic compounds, including flavonoids; tannins and alpha-tocopherol in piquia pulp. No statistically significant differences were observed in the evaluated parameters, demonstrating the absence of cytotoxic and genotoxic effects of piquia pulp at all tested doses. In liver, kidney, cardiac and bone marrow cells, piquia significantly reduced the DNA damage induced by DXR. Our results showed that the lowest piquia dose caused the largest decrease in DNA damage and the highest dose caused the smallest decrease, demonstrating an inverse dose-response of piquia pulp. Furthermore, we observed a difference in the potential antigenotoxic effects in several tissues. In conclusion, our results demonstrated that piquia pulp was not genotoxic and inhibited the genotoxicity induced by DXR, but some of the protective effects that were observed depended on the doses and experimental conditions. Therefore, further investigations are needed to clarify how piquia pulp positively affects human health.

Microbial transformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus

The biotransformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus MT 5.3 yielded a rare derivative that was elucidated by spectrometric methods. The fungus led to the formation of a different product through an unusual epoxidation reaction between C4 and C5, formation of a C3,C10 ether bridge, and a methoxylation of the C1 of tagitinin C. The chemical structure of the product, namely 1 beta-methoxy-3 alpha-hydroxy-3,10 beta-4,5 alpha-diepoxy-8 beta-isobutyroyloxygermacr-11(13)-en-6 alpha,12-olide, is the same as that of a derivative that was recently isolated from the flowers of a Brazilian population of Mexican sunflower (Tithonia diversifolia), which is the source of the substrate tagitinin C. The in vitro cytotoxic activity of the substrate and the biotransformed product were evaluated in HL-60 cells using an MTT assay, and both compounds were found to be cytotoxic. We show that soil fungi may be useful in the biotransformation of sesquiterpene lactones, thereby leading to unusual changes in their chemical structures that may preserve or alter their biological activities, and may also mimic plant biosynthetic pathways for production of secondary metabolites.

Cytotoxicity of cashew flavonoids towards malignant cell lines

The leaves of the Cashew plant (Anacardium occidentale L.) are used by the folk medicine in South America and West Africa. This plant is rich in flavonoids, which are polyphenolic compounds widespread in plants, and that have diverse physiological effects. In a sub-acute toxicity assay it was found that an ethanolic extract of Cashew leaves elicited lymphopenia in rats. The extract was also found to be cytotoxic and to induce apoptosis in Jurkat (acute lymphoblastic leukemia) cells. The crude ethanolic extract was fractionated and resolved by HPLC. One of the four fractions obtained led to the isolation of the biflavonoid agasthisflavone. [H-3]-thymidine incorporation assays and flow cytometry analysis showed that the isolated compound displayed a high anti-proliferative effect in Jurkat cells with an IC50 of 2.4 mu g/ml (4.45 mu M). The effect of agathisflavone on the acute promyelocytic leukemia cell line HL60, Burkitt lymphoma Raji cells and Hep-2 laryngeal carcinoma cells was also tested. The two latter ones were only mildly affected by agathisflavone. It is also shown that agathisflavone induces apoptosis in Jurkat cells and it this proposed that this is the likely mechanism of agathisflavone specific cytotoxicity. (C) 2010 Elsevier GmbH. All rights reserved.

Evaluation of the mutagenic activity of chrysin, a flavonoid inhibitor of the aromatization process

Chrysin is one of the natural flavonoids present in plants, and large amounts are present in honey and propolis. In addition to anticancer, antioxidation, and anti-inflammatory activities, chrysin has also been reported to be an inhibitor of aromatase, an enzyme converting testosterone into estrogen. The present study evaluated the mutagenicity of this flavonoid using micronucleus (MN) with HepG2 cells and Salmonella. Cell survival after exposure to different concentrations of chrysin was also determined using sulforhodamine B (SRB) colorimetric assay in HepG2 cells and the influence of this flavonoid on growth of cells in relation to the cell cycle and apoptosis. TheMN test showed that from 1 to 15 mu M of this flavonoid mutagenic activity was noted in HepG2 cells. The Salmonella assay demonstrated a positive response to the TA100 Salmonella strain in the presence or absence of S9, suggesting that this compound acted on DNA, inducing base pair substitution before or after metabolism via cytochrome P-450. The SRB assay illustrated that chrysin promoted growth inhibition of HepG2 cells in both periods studied (24 and 48 h). After 24 h of exposure it was noted that the most significant results were obtained with a concentration of 50 mu M, resulting in 83% inhibition and SubG0 percentage of 12%. After 48 h of incubation cell proliferation inhibition rates (97% at 50 mu M) were significantly higher. Our results showed that chrysin is a mutagenic and cytotoxic compound in cultured human HepG2 cells and Salmonella typhimurium. Although it is widely accepted that flavonoids are substances beneficial to health, one must evaluate the risk versus benefit relationship and concentrations of these substances to which an individual may be exposed.

Comparison of fast-track diagnostics respiratory pathogens multiplex real-time RT-PCR assay with in-house singleplex assays for comprehensive detection of human respiratory viruses

Fast-track Diagnostics respiratory pathogens (FTDRP) multiplex real-time RT-PCR assay was compared with in-house singleplex real-time RT-PCR assays for detection of 16 common respiratory viruses. The FTDRP assay correctly identified 26 diverse respiratory virus strains, 35 of 41 (85%) external quality assessment samples spiked with cultured virus and 232 of 263 (88%) archived respiratory specimens that tested positive for respiratory viruses by in-house assays. Of 308 prospectively tested respiratory specimens selected from children hospitalized with acute respiratory illness, 270 (87.7%) and 265 (86%) were positive by FTDRP and in-house assays for one or more viruses, respectively, with combined test results showing good concordance (K=0.812, 95% CI = 0.786-0.838). Individual FTDRP assays for adenovirus, respiratory syncytial virus and rhinovirus showed the lowest comparative sensitivities with in-house assays, with most discrepancies occurring with specimens containing low virus loads and failed to detect some rhinovirus strains, even when abundant. The FTDRP enterovirus and human bocavirus assays appeared to be more sensitive than the in-house assays with some specimens. With the exceptions noted above, most FTDRP assays performed comparably with in-house assays for most viruses while offering enhanced throughput and easy integration by laboratories using conventional real-time PCR instrumentation. Published by Elsevier B.V.

A radioenzymatic assay to identify three groups of phospholipase A(2) in platelets

Phospholipases A(2) (PLA(2)) are key enzymes in membrane metabolism. The release of fatty acids and lysophospholipids by PLA(2) activates several intra-cellular second messenger cascades that regulate a wide variety of physiological responses. The aim of the present study is to describe a radioenzymatic assay to determine the activity of three main PLA(2) subtypes in platelets, namely extracellular calcium-dependent PLA(2) (sPLA(2)) and intracellular calcium-dependent (cPLA(2)) and calcium-independent PLA(2) (iPLA(2)). The differentiation of these distinct PLA(2) subtypes was based on the enzyme substrate preference (arachdonic acid or palmitoyl acid) and calcium concentration. Our results indicate that this new assay is feasible, precise and specific to measure the activity of the aforementioned subtypes of PLA(2). Therefore, this protocol can be used to investigate modifications of PLA(2) homeostasis in distinct biological models addressing the pathophysiology of many medical and neuropsychiatric disorders such as schizophrenia and Alzheimer's disease. (C) 2012 Elsevier Ltd. All rights reserved.

Real-time PCR assay targeting the actin gene for the detection of Cryptosporidium parvum in calf fecal samples

Cryptosporidium parvum infection is very important with respect to public health, owing to foodborne and waterborne outbreaks and gastrointestinal illness in immunocompetent and immunocompromised persons. In cattle, infection with this species manifests either as a subclinical disease or with diarrheal illness, which occurs more often in the presence of other infectious agents than when alone. The aim of this study was to develop a real-time polymerase chain reaction (PCR) assay for the detection of C. parvum in calf fecal samples and to compare the results of this assay with those of the method routinely used for the diagnosis of Cryptosporidium spp., nested PCR targeting the 18S rRNA gene. Two hundred and nine fecal samples from calves ranging in age from 1 day to 6 months were examined using real-time PCR specific for the actin gene of C. parvum and by a nested PCR targeting the 18S rRNA gene of Cryptosporidium spp. Using real-time PCR detection, 73.2% (153 out of 209) of the samples were positive for C. parvum, while 56.5% (118 out of 209) of the samples were positive for Cryptosporidium spp. when the nested PCR amplification method was used for the detection. The analytical sensitivity of the real-time PCR was approximately one C. parvum oocyst. There was no significant nonspecific DNA amplification of any of the following species and genotype: Cryptosporidium andersoni, Cryptosporidium baileyi, Cryptosporidium bovis, Cryptosporidium canis, Cryptosporidium galli, Cryptosporidium ryanae, Cryptosporidium serpentis, or avian genotype II. Thus, we conclude that real-time PCR targeting the actin gene is a sensitive and specific method for the detection of C. parvum in calf fecal samples.

Aminoacylase 1-catalysed deacetylation of bioactives epoxides mycotoxin-derived mercapturates; 3,4-epoxyprecocenes as models of cytotoxic epoxides

The mycotoxin aflatoxin B1 (AFB1) is a carcinogenic food contaminant which is metabolically activated by epoxydation. The metabolism of mycotoxins via the mercapturate metabolic pathway was shown, in general, to lead to their detoxication. Mercapturic acids thus formed (S-substitued-N-acetyl-L-cysteines) may be accumulated in the kidney and either excreted in the urine or desacetylated by Acylase 1 (ACY1) to yield cysteine S-conjugates. To be toxic, the N-acetyl-L-cysteine-S-conjugates first have to undergo deacetylation by ACY 1. The specificity and rate of mercapturic acid deacetylation may determine the toxicity, however the exact deacetylation processes involved are not well known. The aim of this study was to investigate the role of ACY1 in the toxicity of some bioactive epoxides from Aflatoxin B1. We characterized the kinetic parameters of porcine kidney and human recombinant aminoacylase-1 towards some aromatic and aliphatic-derived mercapturates analogue of mycotoxin mercapturic acids and 3,4-epoxyprecocene, a bioactive epoxide derivated from aflatoxin. The deacetylation of mercapturated substrates was followed both by reverse phase HPLC and by TNBS method. Catalytic activity was discussed in a structure function relationship. Ours results indicate for the first time that aminoacylase-1 could play an important role in deacetylating mercapturate metabolites of aflatoxin analogues and this process may be in relation with their cyto- and nephrotoxicity in human. (C) 2012 Published by Elsevier Masson SAS.

Genotoxicity assessment of water soluble fractions of biodiesel and its diesel blends using the Salmonella assay and the in vitro MicroFlow (R) kit (Litron) assay

The designation of biodiesel as an environmental-friendly alternative to diesel oil has improved its commercialization and use. However, most biodiesel environmental safety studies refer to air pollution and so far there have been very few literature data about its impacts upon other biotic systems, e.g. water, and exposed organisms. Spill simulations in water were carried out with neat diesel and biodiesel and their blends aiming at assessing their genotoxic potentials should there be contaminations of water systems. The water soluble fractions (WSF) from the spill simulations were submitted to solid phase extraction with C-18 cartridge and the extracts obtained were evaluated carrying out genotoxic and mutagenic bioassays [the Salmonella assay and the in vitro MicroFlow (R) kit (Litron) assay]. Mutagenic and genotoxic effects were observed, respectively, in the Salmonella/microsome preincubation assay and the in vitro MN test carried out with the biodiesel WSF. This interesting result may be related to the presence of pollutants in biodiesel derived from the raw material source used in its production chain. The data showed that care while using biodiesel should be taken to avoid harmful effects on living organisms in cases of water pollution. (C) 2011 Elsevier Ltd. All rights reserved.

SET overexpression decreases cell detoxification efficiency: ALDH2 and GSTP1 are downregulated, DDR is impaired and DNA damage accumulates

Alcohol and tobacco consumption are risk factors for head and neck squamous cell carcinoma (HNSCC). Aldehyde dehydrogenase 2 (ALDH2) and glutathione Stransferase pi 1 (GSTP1) are important enzymes for cellular detoxification and low efficiencies are implicated in cancer. We assessed the potential role of SET protein overexpression, a histone acetylation modulator accumulated in HNSCC, in gene regulation and protein activity of ALDH2 and GSTP1. SET was knocked down in HN13, HN12 and Cal27, and overexpressed in HEK293 cells; ethanol and cisplatin were the chemical agents. Cells with SET overexpression (HEK293/SET, HN13 and HN12) showed lower ALDH2 and GSTP1 mRNA levels and trichostatin A increased them (real-time PCR). Ethanol upregulated GSTP1 and ALDH2 mRNAs, whereas cisplatin upregulated GSTP1 in HEK293 cells. SET-chromatin binding revealed SET interaction with ALDH2 and GSTP1 promoters, specifically via SET NAP domain; ethanol and cisplatin abolished SET binding. ALDH2 and GSTP1 efficiency was assessed by enzymatic and comet assay. A lower ALDH2 activity was associated with greater DNA damage (tail intensity) in HEK293/SET compared with HEK293 cells, whereas HN13/siSET showed ALDH2 activity higher than HN13 cells. HN13/siSET cells showed increased tail intensity. Cisplatin-induced DNA damage response showed negative relationship between SET overexpression and BRCA2 recruitment. SET downregulated repair genes ATM, BRCA1 and CHEK2 and upregulated TP53. Cisplatin-induced cell-cycle arrest occurred in G0/G1 and S in HEK293 cells, whereas HEK293/SET showed G2/M stalling. Overall, cisplatin was more cytotoxic for HN13 than HN13/siSET cells. Our data suggest a role for SET in cellular detoxification, DNA damage response and genome integrity.

PCR colorimetric dot-blot assay and clinical pretest probability for diagnosis of Pulmonary Tuberculosis in Smear-Negative patients

Abstract Background Smear-negative pulmonary tuberculosis (SNPTB) accounts for 30% of Pulmonary Tuberculosis (PTB) cases reported annually in developing nations. Polymerase chain reaction (PCR) may provide an alternative for the rapid detection of Mycobacterium tuberculosis (MTB); however little data are available regarding the clinical utility of PCR in SNPTB, in a setting with a high burden of TB/HIV co-infection. Methods To evaluate the performance of the PCR dot-blot in parallel with pretest probability (Clinical Suspicion) in patients suspected of having SNPTB, a prospective study of 213 individuals with clinical and radiological suspicion of SNPTB was carried out from May 2003 to May 2004, in a TB/HIV reference hospital. Respiratory specialists estimated the pretest probability of active disease into high, intermediate, low categories. Expectorated sputum was examined by direct microscopy (Ziehl-Neelsen staining), culture (Lowenstein Jensen) and PCR dot-blot. Gold standard was based on culture positivity combined with the clinical definition of PTB. Results In smear-negative and HIV subjects, active PTB was diagnosed in 28.4% (43/151) and 42.2% (19/45), respectively. In the high, intermediate and low pretest probability categories active PTB was diagnosed in 67.4% (31/46), 24% (6/25), 7.5% (6/80), respectively. PCR had sensitivity of 65% (CI 95%: 50%–78%) and specificity of 83% (CI 95%: 75%–89%). There was no difference in the sensitivity of PCR in relation to HIV status. PCR sensitivity and specificity among non-previously TB treated and those treated in the past were, respectively: 69%, 43%, 85% and 80%. The high pretest probability, when used as a diagnostic test, had sensitivity of 72% (CI 95%:57%–84%) and specificity of 86% (CI 95%:78%–92%). Using the PCR dot-blot in parallel with high pretest probability as a diagnostic test, sensitivity, specificity, positive and negative predictive values were: 90%, 71%, 75%, and 88%, respectively. Among non-previously TB treated and HIV subjects, this approach had sensitivity, specificity, positive and negative predictive values of 91%, 79%, 81%, 90%, and 90%, 65%, 72%, 88%, respectively. Conclusion PCR dot-blot associated with a high clinical suspicion may provide an important contribution to the diagnosis of SNPTB mainly in patients that have not been previously treated attended at a TB/HIV reference hospital.

In vitro cytotoxicity of white MTA, MTA Fillapex® and Portland cement on human periodontal ligament fibroblasts

The aim of this study was to compare the in vitro cytotoxicity of white mineral trioxide aggregate (MTA), MTA Fillapex® and Portland cement (PC) on human cultured periodontal ligament fibroblasts. Periodontal ligament fibroblast culture was established and the cells were used for cytotoxic tests after the fourth passage. Cell density was set at 1.25 X10 4 cells/well in 96-well plates. Endodontic material extracts were prepared by placing sealer/cement specimens (5X3mm) in 1mL of culture medium for 72 h. The extracts were then serially two-fold diluted and inserted into the cell-seeded wells for 24, 48 and 72 h. MTT assay was employed for analysis of cell viability. Cell supernatants were tested for nitric oxide using the Griess reagent system. MTA presented cytotoxic effect in undiluted extracts at 24 and 72 h. MTA Fillapex® presented the highest cytotoxic levels with important cell viability reduction for pure extracts and at ½ and ¼ dilutions. In this study, PC did not induce alterations in fibroblast viability. Nitric oxide was detected in extract-treated cell supernatants and also in the extracts only, suggesting presence of nitrite in the soluble content of the tested materials. In the present study, MTA Fillapex displayed the highest cytotoxic effect on periodontal ligament fibroblasts followed by white MTA and PC.

Two series of new semisynthetic triterpene derivatives: differences in anti-malarial activity, cytotoxicity and mechanism of action

Background The discovery and development of anti-malarial compounds of plant origin and semisynthetic derivatives thereof, such as quinine (QN) and chloroquine (CQ), has highlighted the importance of these compounds in the treatment of malaria. Ursolic acid analogues bearing an acetyl group at C-3 have demonstrated significant anti-malarial activity. With this in mind, two new series of betulinic acid (BA) and ursolic acid (UA) derivatives with ester groups at C-3 were synthesized in an attempt to improve anti-malarial activity, reduce cytotoxicity, and search for new targets. In vitro activity against CQ-sensitive Plasmodium falciparum 3D7 and an evaluation of cytotoxicity in a mammalian cell line (HEK293T) are reported. Furthermore, two possible mechanisms of action of anti-malarial compounds have been evaluated: effects on mitochondrial membrane potential (ΔΨm) and inhibition of β-haematin formation. Results Among the 18 derivatives synthesized, those having shorter side chains were most effective against CQ-sensitive P. falciparum 3D7, and were non-cytotoxic. These derivatives were three to five times more active than BA and UA. A DiOC6(3) ΔΨm assay showed that mitochondria are not involved in their mechanism of action. Inhibition of β-haematin formation by the active derivatives was weaker than with CQ. Compounds of the BA series were generally more active against P. falciparum 3D7 than those of the UA series. Conclusions Three new anti-malarial prototypes were obtained from natural sources through an easy and relatively inexpensive synthesis. They represent an alternative for new lead compounds for anti-malarial chemotherapy.