Chemical composition variation of essential oils of Copaifera langsdorffii Desf. from different vegetational formations

This study aims to provide information about the chemical profile of the essential oil from C. langsdorffii resin in areas of Cerradão, Carrasco, and Humid Forest. In order to obtain the essential oils, oil-resin was submitted to hydrodistillation process, and the chemical components were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Twenty-six constituents were identified in the essential oil of C. langsdorffii resin, of which 12 were present in Cerradão, 15 in Carrasco and 18 in Humid Forest, with β-bisabolene, caryophyllene oxide, γ-muurolene, α-caryophyllene and β-caryophyllene common to the three phytophysiognomies. Among the studied areas, the resin collection varied from 2.652 g to 20.263 g, while the essential oil yield varied from 2.216 % to 11.764 %. A concentration range of 0.60 % to 84.57 % was recorded among the compounds in the three study areas. There was variation in chemical composition both among phytophysiognomies and among individuals from the same location, where β-caryophyllene showed to be the majority for all areas studied, being present in all individuals from Cerradão, Carrasco and Humid Forest.

Dioclea violacea lectin increases the effect of neomycin against multidrug-resistant strains and promotes the purification of the antibiotic in immobilized lectin column

DVL is a Man/Glc-binding lectin from Dioclea violacea seeds that has the ability to interact with the antibiotic gentamicin. The present work aimed to evaluate whether the DVL has the ability to interact with neomycin via CRD and to examine the ability of this lectin to modulate the antibiotic effect of neomycin against multidrug-resistant strains (MDR). The hemagglutinating activity test revealed that neomycin inhibited the hemagglutinating activity of DVL with a minimum inhibitory concentration of 50 mM, indicating that the antibiotic interacts with DVL via the carbohydrate recognition domain (CRD). DVL immobilized on cyanogen bromide-activated Sepharose® 4B bound 41 % of the total neomycin applied to the column, indicating that the DVL-neomycin interaction is efficient for purification processes. Furthermore, the minimum inhibitory concentrations (MIC) obtained for DVL against all strains studied were not clinically relevant. However, when DVL was combined with neomycin, a significant increase in antibiotic activity was observed against S. aureus and P. aeruginosa. These results demonstrate the first report of lectin-neomycin interaction, indicating that immobilized DVL has the potential to isolate neomycin by affinity chromatography. Moreover, DVL increased the antibiotic activity of neomycin against MDR, suggesting that it is a potent adjuvant in the treatment of infectious diseases.

LC-MS Analysis and Antifungal Activity of Turnera subulata Sm

Fungi of the Candida genus are responsible for invasive candidiasis, which affects people all over the world and has high mortality rates. This is due to their virulence factors, which give them great resistance and pathogenicity. In addition, the emergence of multidrug-resistant strains makes it difficult to treat these infections. In this way, natural products have emerged as an alternative to standard drugs, where plants known for their medicinal properties such as Turnera subulata become attractive to research. The present work aimed to analyze the ethanol extract of Turnera subulata leaves against standard strains of Candida albicans, Candida krusei and Candida tropicalis using broth microdilution techniques. The identification of the compounds in T. subulata leaves by LC-MS revealed the presence of a wide variety of substances such as carboxylic acids and terpenes, with flavonoids and fatty acids being more evident. The antifungal assays showed that the extract was not able to inhibit the growth of the tested strains at concentrations with a clinical relevance. However, at higher concentrations, it was able to inhibit the fungal dimorphism of C. albicans and C. tropicalis. It is possible that the T. subulata extract has potential as an inhibitor of fungal virulence factors without affecting the cell viability. Further research should be carried out in order to assess its inhibitory potential for other fungal virulence factors.

Demonstration of microRNA using in situ hybridisation on formalin fixed paraffin wax samples using conventional oligonucleotide probes: a comparison with the use of locked nucleic acid probes

BACKGROUND

MicroRNAs (miRNAs) regulate the translation of mRNA during gene expression and investigations have highlighted their importance in pathophysiology. qRT-PCR is currently the gold standard method for detecting changes in miRNA expression. However, when used on heterogeneous samples, it cannot identify individual cell types harbouring miRNAs. For this, in situ hybridisation (ISH) can be used. ISH methods using locked nucleic acid (LNA) probes give reliable results in formalin fixed paraffin-embedded (FFPE) samples. In this study their use has been directly compared with conventional oligonucleotide probes (COP) for ISH.

METHODS

FFPE samples of colorectal adenocarcinoma, squamous carcinoma of lung and cases of invasive breast carcinoma were used to evaluate COP and LNA methods for the demonstration of miR-126 and miR-205. To demonstrate the utility of the COP method demonstration of miR-21 in 19 Gleason stage 7 prostate biopsy FFPE tissues was also undertaken. The demonstration of miR-21 by ISH in high and low expressing prostate cancer cell lines was also compared with qRT-PCR.

RESULTS

Similar results were obtained using the COP and LNA ISH methods for the demonstration of miR-126 and miR-205. miR-21 was successfully demonstrated in the prostate cancer samples by COP ISH and expression levels of the miRNA demonstrated in the cell lines corresponded with qRT-PCR.

CONCLUSION

This study has shown that simplification of ISH protocols by the use of COPs provides equivalent results to the use of LNA methods and it can be used to precisely identify cells in which miRNAs are expressed.

Age-dependent hepatic alterations induced by a high-fat high-fructose diet

OBJECTIVE

The present study aimed to evaluate and clarify how the age at which the intake of a high-fat and high-fructose diet begins can affect animals' livers.

METHODS

Thirty-eight male wistar rats aged 6 and 12 weeks were fed a high-fat and high-fructose diet for 13 weeks. Inflammatory cytokines, hepatic glycogen, serum and hepatic triacylglycerol and pAkt protein content in the liver were assessed. Percentage of weight gained, and visceral adiposity were also evaluated.

RESULTS

Young animal presented increased hepatic triacylglycerol and decreased glycogen, while adult animals had no significant alterations regarding its contents. IL6 and IL10 to IL6 ratio were also altered in young animals exposed to HFHF, while adult animals fed with HFHF had only increases in TNF-α. Both groups which received HFHF had increased serum triacylglycerol and visceral adiposity. However, only young animals gained more relative weight and had greater final body weight, gains which were related to alterations found in hepatic triacylglycerol and glycogen.

CONCLUSION

Age of which consumption begins interferes in how the liver deals with an excess of nutrient and subsequent proinflammatory stimulation, leading to different phenotypes.

Analysis of the Variability of Therapeutic Indications of Medicinal Species in the Northeast of Brazil: Comparative Study

ETHNOPHARMACOLOGICAL RELEVANCE

This study aims to evaluate the versatility of these species and their agreement of use and/or the informants' knowledge and verify the variability of the information on the indicated medicinal species in comparison to other species from northeastern Brazilian areas.

MATERIALS AND METHODS

Ethnobotanical information was acquired through interviews with 23 residents of the Quincuncá community, northeastern Brazil. From the obtained data, a comparative analysis of the therapeutic indications with other 40 areas in different biomes was conducted. For that, the relative importance index and informant consensus factor were calculated and compared to other indices evaluated in the literature.

RESULTS

A total of 39 medicinal species were cited and twenty-six species showed similarities among their therapeutic indications; however, species as Geoffroea spinosa, Lantana camara, and others can be highlighted, present in community disease indications that were not verified for other areas. Myracrodruon urundeuva, Mimosa tenuiflora, Stryphnodendron rotundifolium, and Amburana cearensis had the greatest versatility. In the Quincuncá community, medicinal species were indicated for 49 diseases, which were grouped into 15 categories of body systems.

CONCLUSION

This study shows the presented divergence in relation to their therapeutic use; in this point, these divergences reinforce the importance of pharmacological research.

Exposure to crack cocaine causes adverse effects on marine mussels Perna perna

Our study aimed to evaluate crack cocaine effects in different life stages of the marine mussel Perna perna. For this purpose, fertilization rate, embryo-larval development, lysosomal membrane stability and DNA strand breaks were assessed. Effect concentrations in gametes and in larval development were found after 1h (IC₅₀=23.53mg·L^-1) and 48h (IC₅₀=16.31mg·L^-1), respectively. The highest tested concentration showing no acute toxicity (NOEC) was 10mg·L^-1, while the lowest observed effect concentration (LOEC) was 20mg·L^-1. NOEC concerning embryo-larval development was 0.625mg·L^-1, while the LOEC was 1.25mg·L^-1. Cyto-genotoxic effects were evidenced in mussels exposed to crack cocaine concentrations ranging from 5 to 500μg·L^-1. Our results report the first data on effects of an illicit drug to marine organisms and should encourage further ecotoxicological studies of these contaminants of emerging concern in coastal ecosystems.

Gum acacia mitigates genetic damage in adenine-induced chronic renal failure in rats

BACKGROUND

Subjects with chronic renal failure (CRF) exhibit oxidative genome damage, which may predispose to carcinogenesis, and Gum acacia (GumA) ameliorates this condition in humans and animals. We evaluated here renal DNA damage and urinary excretion of four nucleic acid oxidation adducts namely 8-oxoguanine (8-oxoGua), 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), 8-oxoguanosine (8-oxoGuo) and 8-hydroxy-2-deoxyguanisone (8-OHdg) in rats with adenine (ADE)-induced CRF with and without GumA treatment.

MATERIALS AND METHODS

Twenty-four rats were divided into four equal groups and treated for 4 weeks. The first group was given normal food and water (control). The second group was given normal food and GumA (15% w/v) in drinking water. The third group was fed powder diet containing adenine (ADE) (0·75% w/w in feed). The fourth group was fed like in the third group, plus GumA in drinking water (15%, w/v).

RESULTS

ADE feeding induced CRF (as measured by several physiological, biochemical and histological indices) and also caused a significant genetic damage and significant decreases in urinary 8-oxo Gua and 8-oxoGuo, but not in the other nucleic acids. However, concomitant GumA treatment reduced the level of genetic damage in kidney cells as detected by Comet assay and significantly reversed the effect of adenine on urinary 8-oxoGuo.

CONCLUSIONS

Treatment with GumA is able to mitigate genetic damage in renal tissues of rats with ADE-induced CRF.

Plant species as a therapeutic resource in areas of the savanna in the state of Pernambuco, Northeast Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnobotanical studies have contributed significantly in research of plants with therapeutic potential. The aim of the present study was to learn about the use of native medicinal plants cited by the traditional population in "cerradão" (savanna woodland) areas in Northeast Brazil, providing data on therapeutic indications of the species used and their versatility.

MATERIALS AND METHODS

Semi-structured interviews were conducted on the basis of a standardized questionnaire designed for key informants selected using the "snowball" technique. The selection of plants species with therapeutic potential was performed on the basis of the relative importance (RI) and informant consensus fator (ICF).

RESULTS

A total of 78 species were indicated for 87 therapeutic purposes. Of these, 11 species presented great versatility of use (RI>1), as e.g.including Copaifera langsdorffii Desf., Hybanthus calceolaria (Mart.) Plumel., Heliotropium cf. indicum L., Croton zehntneri, Croton heliotropiifolius, Myracrodruon urundeuva, Stryphnodendro rotundifolium. Medicinal uses could be generalized Pax & K. Hoffm and Hymenaea courbaril L. The therapeutic indications were grouped into 14 use 15 categories with 594 species-category combinations. The largest number of medicinal species was indicated for illnesses or undefined pain, followed by diseases associated with respiratory, digestive and genitourinaryof body systems. The factor informant consensus highlighted the agreement in the use of plants and showed that the, of which Diseases of the Nervous System and, Diseases of the Circulatory System had the greatest agreement 1.0 and 0.87 repectively, Disorders of the Visual Sensory System - Eyes and Respiratory System Disorder showed the highest agreement of use.

CONCLUSIONS

Most of the species cited by the key informants are well known scientifically, but it is interesting that some have been studied little or not all with regard to confirming their purported medicinal properties and can contribute substantially to pharmacological and phytochemical investigations in the search for new drugs.

Characterization and biocompatibility of a fibrous glassy scaffold

Bioactive glasses (BGs) are known for their ability to bond to living bone and cartilage. In general, they are readily available in powder and monolithic forms, which are not ideal for the optimal filling of bone defects with irregular shapes. In this context, the development of BG-based scaffolds containing flexible fibres is a relevant approach to improve the performance of BGs. This study is aimed at characterizing a new, highly porous, fibrous glassy scaffold and evaluating its in vitro and in vivo biocompatibility. The developed scaffolds were characterized in terms of porosity, mineralization and morphological features. Additionally, fibroblast and osteoblast cells were seeded in contact with extracts of the scaffolds to assess cell proliferation and genotoxicity after 24, 72 and 144 h. Finally, scaffolds were placed subcutaneously in rats for 15, 30 and 60 days. The scaffolds presented interconnected porous structures, and the precursor bioglass could mineralize a hydroxyapatite (HCA) layer in simulated body fluid (SBF) after only 12 h. The biomaterial elicited increased fibroblast and osteoblast cell proliferation, and no DNA damage was observed. The in vivo experiment showed degradation of the biomaterial over time, with soft tissue ingrowth into the degraded area and the presence of multinucleated giant cells around the implant. At day 60, the scaffolds were almost completely degraded and an organized granulation tissue filled the area. The results highlight the potential of this fibrous, glassy material for bone regeneration, due to its bioactive properties, non-cytotoxicity and biocompatibility. Future investigations should focus on translating these findings to orthotopic applications. Copyright © 2015 John Wiley & Sons, Ltd.

Ethnopharmacology of medicinal plants of carrasco, northeastern Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

The goal of this study was to conduct an ethnobotanical survey of medicinal species from the carrasco vegetation of the Araripe National Forest, state of Ceará, Brazil, as well as determining species with bioprospecting potential

MATERIALS AND METHODS

The ethnobotanical data were collected through semi-structured interviews and a free list. The relative importance of the plants cited was assessed, as well as species that stood out with respect to bodily systems, on the basis of informant consensus.

RESULTS

A total of 32 species belonging to 29 genera and 20 families were recorded. Of this total, six species (19%) showed great versatility regarding their uses in regard to up to seven bodily systems. The therapeutic indications were grouped into 14 categories of bodily systems. Circulatory and genitourinary disorders, endocrine, nutritional and metabolic diseases, and undefined pain or disease showed the greatest consensus between informants.

CONCLUSIONS

Ximenia americana, Himathantus drasticus, Stryphnodndron rotundifolium, Bowdichia virgilioides, and Hymenaea courbaril were the species warranting more in-depth study, on the basis of versatility and informant consensus on the uses of the species.

Promising medicinal plants for bioprospection in a Cerrado area of Chapada do Araripe, Northeastern Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional medical systems represent an important source of knowledge about the use of biodiversity. Ethnobotanical and ethnopharmacological studies can encourage bioprospecting in the pursuit and selection of promising medicinal plants. This study investigated the diversity of medicinal plants in a disjunct area of cerrado in Chapada do Araripe, Ceará, Brazil, and assessed the species of interest for bioprospecting.

MATERIALS AND METHODS

Structured and semi-structured interviews were conducted through free listing, and the informants were recruited using the "snowball" technique. The relative importance and informant consensus factor were analyzed for the selection of plant species with therapeutic potential.

RESULTS

A total of 68 species were recorded and cited for 91 therapeutic purposes. Of these, 10 species showed great versatility of use, including Copaifera langsdorffii Desf., Caryocar coriaceum Wittn., Himatanthus drasticus (Mart.) Plumel, Stryphnodendron rotundifolium Mart., and Dimorphandra garderiana Tull. The therapeutic citations were grouped into 16 categories of body systems, of which Injuries, Poisonings and Other Consequences of External Causes, and Neoplasias showed the highest agreement of use.

CONCLUSIONS

Regarding the diversity of the species, some including Tocoyena Formosa (Cham. & Schlecht.) Schum., Himatanthus drasticus, Caryocar coriaceum, Roupala montana Aubl. and Stryphnodendron rotundifolium showed both high relative importance and strong consensus among informants, and although many have already been investigated scientifically, others are almost unknown with respect to their medicinal properties and can be targets for bioprospecting.

Insulin resistance is associated with DNA damage in peripheral blood cells in non-diabetic patients with genotype 1 chronic hepatitis C

BACKGROUND

In chronic liver diseases of different etiologies, including viral hepatitis, genotoxic effects of oxidative stress have been shown, both in clinical and in experimental conditions, suggesting that this mechanism may contribute to the evolution of the disease.

AIM

To evaluate DNA damage in the peripheral blood of untreated non-diabetic patients with chronic hepatitis C and control subjects, and its correlation with demographic, anthropometric, biochemical, and histological parameters in the patient sample.

PATIENTS AND METHODS

This study comprised 100 subjects of both genders, 60 of whom were treatment-naïve patients with positive serology for genotype 1 hepatitis C. The remaining 40 were blood donors with negative serology for hepatitis who were used as control subjects, and matched by gender, age, weight, and BMI. DNA damage was determined using the comet assay in the total peripheral blood.

RESULTS

The DNA damage evaluated by the comet assay revealed higher values in the group of patients with hepatitis compared with that in the control group. The relationships of the comet assay with the studied variables were assessed using multivariate analysis; significant correlations were only identified with insulin (r = 0.343, p = 0.008) and Homeostasis Model Assessment Insulin Resistance (HOMA-IR) (r = 0.331, p = 0.011).

CONCLUSION

Patients with genotype 1 chronic hepatitis C have higher rates of DNA damage, as determined by comet assay and this alteration is correlated with the HOMA index of insulin resistance.

Cytogenetic biomonitoring in oral mucosa cells following dental X-ray

OBJECTIVES

In the past decades, X-rays have been used widely for diagnosis in dentistry. However, it is well known that ionizing radiation causes damage (including single- and double-strand breaks) to deoxyribonucleic acid (DNA) and DNA-protein crosslinks, and induces cellular death. Therefore, outlining the cytogenetic effects induced by X-ray is necessary to identify the degree of cancer risk and minimize potential risks to patients and clinicians. To date, a variety of assays have been proposed in cytogenetic biomonitoring studies, including those that assess metaphase chromosomal aberrations and sister chromatid exchanges, and micronucleus and single-cell gel (comet) assay.

METHODS

Cytogenetic biomonitoring studies focusing on oral mucosa cells in individuals exposed to dental X-ray were reviewed.

RESULTS

Dental X-ray can induce DNA damage and cytotoxicity in oral mucosa cells.

CONCLUSION

These results will contribute to a better understanding of X-ray-induced effects upon the cellular system in individuals continually exposed to known genotoxic/cytotoxic agents.

Comparison of oral versus sublingual piroxicam during postoperative pain management after lower third molar extraction

In this study, 53 patients received piroxicam, administered orally or sublingually, after undergoing removal of symmetrically positioned lower third molars, during two separate appointments. This study used a randomized, blind, cross-over protocol. Objective and subjective parameters were recorded for comparison of postoperative results for 7 days after surgery. Patients treated with oral or sublingual piroxicam reported low postoperative pain scores. The patients who received piroxicam orally took a similar average amount of analgesic rescue medication compared with patients who received piroxicam sublingually (p>0.05). Patients exhibited similar values for mouth opening measured just before surgery and immediately following suture removal 7 days later (p>0.05), and showed no significant differences between routes of piroxicam administration for swelling control during the second or seventh postoperative days (p>0.05). In summary, pain, trismus and swelling after lower third molar extraction, independent of surgical difficulty, could be controlled by piroxicam 20mg administered orally or sublingually and no significant differences were observed between the route of delivery used in this study.

Mutagenicity and cytotoxicity assessment in patients undergoing orthodontic radiographs

OBJECTIVES

The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated buccal mucosa cells from individuals following radiography.

METHODS

Lateral and frontal cephalometric X-ray and panoramic dental X-rays were taken of a total of 18 healthy patients (6 male and 12 female) referred for orthodontic therapy. Exfoliated oral mucosa cells were collected immediately before X-ray exposure and after 10 days.

RESULTS

The results revealed no statistically significant difference (P > 0.05) in the frequency micronucleated oral mucosa cells after X-ray exposure. However, X-ray was able to increase other nuclear alterations closely related to cytotoxicity, such as karyorrhexis, pyknosis and karyolysis.

CONCLUSIONS

Data indicated that exposure to certain radiography may not be a factor in inducing chromosomal damage, but it does promote cytotoxicity.

Sleep loss and acute drug abuse can induce DNA damage in multiple organs of mice

The purpose of the present study was to characterize the genetic damage induced by paradoxical sleep deprivation (PSD) in combination with cocaine or ecstasy (3,4-methylenedioxymethamphetamine; MDMA) in multiple organs of male mice using the single cell gel (comet) assay. C57BL/6J mice were submitted to PSD by the platform technique for 72 hours, followed by drug administration and evaluation of DNA damage in peripheral blood, liver and brain tissues. Cocaine was able to induce genetic damage in the blood, brain and liver cells of sleep-deprived mice at the majority of the doses evaluated. Ecstasy also induced increased DNA migration in peripheral blood cells for all concentrations tested. Analysis of damaged cells by the tail moment data suggests that ecstasy is a genotoxic chemical at the highest concentrations tested, inducing damage in liver or brain cells after sleep deprivation in mice. Taken together, our results suggest that cocaine and ecstasy/MDMA act as potent genotoxins in multiple organs of mice when associated with sleep loss.

Biomonitoring of DNA damage and cytotoxicity in individuals exposed to cone beam computed tomography

OBJECTIVES

The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated buccal mucosa cells from adults following cone beam CT exposure.

METHODS

A total of 19 healthy adults (10 men and 9 women) submitted to cone beam CT were included.

RESULTS

No significant statistically differences (P > 0.05) in micronucleus frequency were seen before and after cone beam CT exposure. In contrast, the tomography was able to increase other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis (P < 0.05).

CONCLUSION

In summary, these data indicate that cone beam CT may not be a factor that induces chromosomal damage, but it is able to promote cytotoxicity.

Ex vivo assessment of genotoxicity and cytotoxicity in murine fibroblasts exposed to white MTA or white Portland cement with 15% bismuth oxide

AIMS

To evaluate whether white mineral trioxide aggregate (MTA) or white Portland cement with 15% bismuth oxide were able to induce genetic damage and cellular death ex vivo.

METHODOLOGY

Aliquots of 1 × 10(4) murine fibroblasts were incubated at 37 °C for 3 h with MTA (white) or white Portland cement with 15% bismuth oxide, at final concentrations ranging from 10 to 1000 μg mL(-1) individually. Data of three independent repeats from the comet assay and the trypan blue exclusion test were assessed by the one-way anova followed by Tukey's test.

RESULTS

Mineral trioxide aggregate or Portland cement containing bismuth oxide did not produce genotoxic effects with respect to the single-cell gel (comet) assay data for all concentrations evaluated. Furthermore, no cytotoxicity was observed for MTA or Portland cement.

CONCLUSION

White MTA or white Portland cement containing 15% bismuth oxide were not genotoxic and cytotoxic.

Distinct effects of acute and chronic sleep loss on DNA damage in rats

The aim of this investigation was to evaluate genetic damage induced in male rats by experimental sleep loss for short-term (24 and 96 h) and long-term (21 days) intervals, as well as their respective recovery periods in peripheral blood, brain, liver and heart tissue by the single cell gel (comet) assay. Rats were paradoxically deprived of sleep (PSD) by the platform technique for 24 or 96 h, or chronically sleep-restricted (SR) for 21 days. We also sought to verify the time course of their recovery after 24 h of rebound sleep. The results showed DNA damage in blood cells of rats submitted to PSD for 96 h. Brain tissue showed extensive genotoxic damage in PSD rats (both 24 and 96 h), though the effect was more pronounced in the 96 h group. Rats allowed to recover from the PSD-96 h and SR-21 days treatments showed DNA damage as compared to negative controls. Liver and heart did not display any genotoxicity activity. Corticosterone concentrations were increased after PSD (24 and 96 h) relative to control rats, whereas these levels were unaffected in the SR group. Collectively, these findings reveal that sleep loss was able to induce genetic damage in blood and brain cells, especially following acute exposure. Since DNA damage is an important step in events leading to genomic instability, this study represents a relevant contribution to the understanding of the potential health risks associated with sleep deprivation.

Chronic renal failure induces genetic instability in multiple organs of Wistar rats

BACKGROUND

Taking into consideration the strong evidence for a relationship between DNA damage and carcinogenesis, the aim of this study was to investigate whether blood, liver, heart, kidney and brain are particularly sensitive organs for DNA damaging during chronic renal disease by the single-cell gel (comet) assay to predict genetic instability induced by this pathological condition.

METHODS

A total of 18 male Wistar rats were divided into two groups: negative control (n = 8) and experimental (n = 10), in which was submitted to the 5/6 renal mass ablation by ligation of two or three branches of the left renal artery and total right nephrectomy during 8 weeks.

RESULTS

The results showed that chronic renal disease was able to induce genetic damage in blood, heart, liver and kidney cells as depicted by the mean tail moment. No genetic damage was induced in brain cells, i.e. no significant statistically differences (P > 0.05) were noticed when compared to negative control.

CONCLUSION

In conclusion, our results suggest that chronic renal failure could contribute to the damage of DNA at all organs evaluated, except to the brain cells. As DNA damage is an important step in events leading to carcinogenesis, this study represents a relevant contribution to the correct evaluation of the potential health risks associated with kidney disease.

Cytogenetic biomonitoring in patients exposed to dental X-rays: comparison between adults and children

OBJECTIVES

The aim of the present study was to comparatively evaluate the DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) of exfoliated buccal mucosa cells from children and adults following dental X-ray exposure.

METHODS

A total of 17 adults and 17 children submitted to panoramic dental radiography were included in this study.

RESULTS

The results indicated no statistically significant differences (P > 0.05) in children's micronucleated oral mucosa cells before and after dental X-ray exposure. In the same way, no mutagenic effects were observed in adults following X-ray exposure. On the other hand, X-rays increased other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis in both groups. The comparative analysis between children and adults demonstrated no statistically significant differences in micronucleus frequency or cytotoxicity (P > 0.05).

CONCLUSIONS

In summary, these data indicate that dental paroramic radiography may not be a factor that induces chromosomal damage, but it is able to promote cytotoxicity. It seems that children are not more susceptible to the noxious activities induced by X-rays when compared with adults.

DNA damage in lymphocytes and buccal mucosa cells of children with malignant tumours undergoing chemotherapy

The aim of the present study was to evaluate DNA damage (micronucleus) in cytokinesis-blocked lymphocytes and exfoliated buccal mucosa cells from children with malignant tumours and under chemotherapy. Micronucleated cells (MNCs) were assessed from children before and during chemotherapy. A total of 21 healthy children (controls), matched for gender and age, were used as control. The results pointed out higher frequencies of micronucleated lymphocytes in children with malignant tumour before any therapy when compared to healthy probands. Furthermore an increase of micronucleated lymphocytes during chemotherapy was detected when compared to the data obtained before chemotherapy. No statistically significant increases of MNCs were noticed in buccal mucosa cells at any of the timepoints evaluated. Taken together, these data indicate that the presence of malignant tumours may increase the frequency of DNA damage in circulating lymphocytes, these cells being more sensitive for detecting chromosome aberrations caused by anti-cancer drugs.

Lack of effect of prior treatment with fluoride on genotoxicity of two chemical agents in vitro

The goal of this study was to investigate the ability of fluoride to modulate the genotoxic effects induced by the oxidative agent hydrogen peroxide (H2O2) and the alkylating agent methyl methanesulfonate (MMS) in vitro by the single-cell gel (comet) assay. Chinese hamster ovary cells were exposed in culture for 1 h at 37 degrees C to sodium fluoride at 7-100 microg/ml. NaF-treated and control cells were then incubated with 0-10 microM MMS in phosphate-buffered saline (PBS) for 15 min at 37 degrees C, or 0-100 microM H2O2 in distilled water for 5 min on ice. Negative control cells were treated with PBS for 1 h at 37 degrees C. Clear concentration-related effects were observed for the two genotoxins. Increase of DNA damage induced by either MMS or H2O2 was not significantly altered by pretreatment with NaF. The data indicate that NaF does not modulate alkylation-induced genotoxicity or oxidative DNA damage as measured by the single-cell gel (comet) assay.

Lycopene activity against chemically induced DNA damage in Chinese hamster ovary cells

Lycopene is a natural pigment synthesized by plants and microorganisms, and it is mainly found in tomatoes. It is an acyclic isomer of beta-carotene and one of the most potent antioxidants. Several studies have demonstrated the ability of lycopene to prevent chemically induced DNA damage; however, the mechanisms involved are still not clear. In the present study, we investigated the antigenotoxic/antimutagenic effects of lycopene in Chinese Hamster Ovary Cells (CHO) treated with hydrogen peroxide, methylmethanesulphonate (MMS), or 4-nitroquinoline-1-oxide (4-NQO). Lycopene (97%), at final concentrations of 10, 25, and 50 microM, was tested under three different protocols: before, simultaneously, and after the treatment with the mutagens. Comet and cytokinesis-block micronucleus assays were used to evaluate the level of DNA damage. Data showed that lycopene reduced the frequency of micronucleated cells induced by the three mutagens. However, this chemopreventive activity was dependent on the concentrations and treatment schedules used. Similar results were observed in the comet assay, although some enhancements of primary DNA damage were detected when the carotenoid was administered after the mutagens. In conclusion, our findings confirmed the chemopreventive activity of lycopene, and showed that this effect occurs under different mechanisms.

Biocompatibility of glass?ionomer cements using mouse lymphoma cells in vitro

Glass-ionomer cements are widely used in dentistry as restorative materials and adhesives for composite restorations. A number of genotoxicity studies have been conducted using these materials with results conflicting so far. Thus, the approach was aimed to look at the genotoxic and cytotoxic potential of three different glass-ionomer cements available commercially (Ketac Cem, Ketac Molar and Vitrebond) by the single cell gel (comet) assay and trypan blue exclusion test, respectively. For this, such materials were exposed to mouse lymphoma cells in vitro for 1 h at 37 degrees C. Data were assessed by Kruskall-Wallis non-parametric test. The results showed that all powders assayed did not show genotoxic effects. On the other hand, the liquid from Vitrebond at 0.1% dilution caused an increase of DNA injury. Significant statistically differences (P < 0.05) in cytotoxicity provoked by all powders tested were observed for exposure at 1,000 micro g mL(-1) concentration and 100 micro g mL(-1) for Ketac Molar. With respect to liquids of glass-ionomer cements evaluated, the major toxic effect on cell viability was produced at 1%, beginning at the dilution of 0.5% for Vitrebond. Taken together, these results support the notion that some components of glass-ionomer cements show both genotoxic and cytotoxic effects in higher concentrations.

Brazilian natural dietary components (annatto, propolis and mushrooms) protecting against mutation and cancer

Considering the high number of new cancer cases in Brazil (approximately 470000 cases in 2005) and the remarkable differences in the incidence of this disease around the world, the development of chemopreventive strategies using foods widely consumed would have a huge impact, both medically and economically. This review summarizes some of our studies conducted to verify the anti-mutagenic and anti-carcinogenic potential of some Brazilian natural dietary constituents (annatto, mushrooms, and propolis). Overall data have shown a clear role for these compounds in preventing mutation and specific preneoplastic lesions. Taken together, these agents indicate a favorable side-effect profile and may prove to be a promising alternative for cancer prevention strategies, although more investigation is needed to fully explore this issue.

Evaluation of genetic damage in human peripheral lymphocytes exposed to mineral trioxide aggregate and Portland cements

summary Mineral trioxide aggregate (MTA) and Portland cement are being used in dentistry as root-end-filling material for periapical surgery and for the sealing of communications between the root canal system and the surrounding tissues. However, genotoxicity tests for complete risk assessment of these compounds have not been conducted up to now. In the present study, the genotoxic effects of MTA and Portland cements were evaluated in peripheral lymphocytes from 10 volunteers by the alkaline single cell gel (comet) assay. The results pointed out that the single cell gel (comet) assay failed to detect the presence of DNA damage after a treatment of peripheral lymphocytes by MTA and Portland cements for concentrations up to 1000 mug mL(-1). In summary, our results indicate that exposure to MTA or Portland cements may not be a factor that increases the level of DNA lesions in human peripheral lymphocytes as detected by single cell gel (comet) assay.

Ex vivo biocompatibility tests of regular and white forms of mineral trioxide aggregate

AIM

To examine the genotoxicity and cytotoxicity of regular and white mineral trioxide aggregate (MTA) ex vivo by the single-cell gel (comet) assay and trypan blue exclusion test, respectively.

METHODOLOGY

Aliquots of 1 x 10(4) Chinese hamster ovary cells were incubated at 37 degrees C for 3 h with grey and white forms of MTA at final concentrations ranging from 1 to 1,000 microg mL(-1). The negative control group was treated with vehicle control phosphate buffer solution for 3 h at 37 degrees C and the positive control group was treated with methyl metasulfonate (at 1 microg mL(-1)) for 1 h at 37 degrees C. After incubation, the cells were centrifuged at 180 g for 5 min and washed twice with fresh medium and resuspended with fresh medium. Each individual treatment was repeated three times consecutively to ensure reproducibility. Parameters from single-cell gel (comet) and cytotoxicity assays were assessed by the Kruskal-Wallis nonparametric test.

RESULTS

Neither compounds produced genotoxic effects with respect to the single-cell gel (comet) assay in all concentrations evaluated. In the same way, the dose-response relationships of all compounds tested at concentrations ranging from 1 to 1,000 microg mL(-1) on cell viability assessed by the trypan blue assay displayed no statistically significant differences (P > 0.05) for either endodontic material.

CONCLUSIONS

Regular (grey) and white MTA are not genotoxins and do not induce cellular death.

Assessment of genetic damage induced by dental bleaching agents on mouse lymphoma cells by single cell gel (comet) assay

Dental bleaching is a simple and conservative procedure for aesthetic restoration of vital discoloured teeth. However, dental bleaching agents may represent a hazard to human health, especially by causing DNA strand breaks. Genotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. In the current study, the genotoxic potential associated with exposure to dental bleaching agents was assessed by the single cell gel (comet) assay in vitro. Six commercial dental bleaching agents (Clarigel Gold - Dentsply; Whitespeed - Discus Dental; Nite White - Discus Dental; Magic Bleaching - Vigodent; Whiteness HP - FGM and Lase Peroxide - DMC) were exposed to mouse lymphoma cells in vitro. The results pointed out that all dental bleaching agents tested contributed to the DNA damage as depicted by the mean tail moment. Clear concentration-related effects were obtained for DNA damaging, being the strongest effect observed at the highest dose of the hydrogen peroxide (Whiteness HP and Lase Peroxide, at 35% concentration). On the contrary, Whitespeed (Discus Dental) induced the lowest level of DNA breakage. Taken together, these results suggest that dental bleaching agents may be a factor that increases the level of DNA damage as detected by the single cell gel (comet) assay.

No relationship between subchronic fluoride intake and DNA damage in Wistar rats

Fluoride has been widely used in dentistry because it is an effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury on the genetic apparatus. Genotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. In the current study, the potential DNA damage associated with exposure to fluoride was assessed by the single cell gel (comet) assay in peripheral blood, oral mucosa and brain cells in vivo. Male Wistar rats were exposed to sodium fluoride (NaF) at a 0, 7 and 100 ppm dose for drinking water during 6 weeks. The results pointed out that NaF did not contribute to the DNA damage in all cellular types evaluated as depicted by the mean tail moment and tail intensity. These findings are clinically important since they represent an important contribution to the correct evaluation of the potential health risk associated with dental agents exposure.

Does toxoplasmosis cause DNA damage? An evaluation in isogenic mice under normal diet or dietary restriction

Toxoplasmosis is an anthropozoonotic widespread disease, caused by the coccidian protozoan parasite Toxoplasma gondii. Since there are no data regarding the genotoxicity of the parasite in vivo, this study was designed to evaluate the genotoxic potential of the toxoplasmosis on isogenic mice with normal diet or under dietary restriction and submitted to a treatment with sulfonamide (375 microg/kg per day). DNA damage was assessed in peripheral blood, liver and brain cells using the comet assay (tail moment). The results for leucocytes showed increases in the mean tail moment in mice under dietary restriction; in infected mice under normal diet; in infected, sulfonamide-treated mice under normal diet; in infected mice under dietary restriction and in infected sulfonamide-treated mice under dietary restriction. In liver and brain cells, no statistically significant difference was observed for the tail moment. These results indicated that dietary restriction and T. gondii were able to induce DNA damage in peripheral blood cells, as detected by the comet assay.

[Brain changes in leukemias. Histopathological aspects of choroid plexus involvement]

In the study of 38 cases of leukemia, neoplastic infiltration of the brain was the most frequent lesion, occuring in 70,5%, compared to 48,5% for hemorrhage. The leptomeninges were the most frequent site of leukemic infiltration followed by the choroid plexus (57,8%) and the nervous tissue (50%). In few cases leukemic infiltration of choroid plexus was seen in the absence of meningeal involvement. Very often the leukemic infiltration of the CNS courses without clinical manifestations. The paper points out the importance of the cytologic study of the cerebro-spinal fluid as a routine procedure in cases of leukemia, since it is well known that the therapeutic agents have difficulty in penetrating the blood-brain barrier and that foci of CNS leukemic infiltration may represent points of reactivation points of reactivation of the disease even during the therapeutic remission.