Antimicrobial and antitumor activities of an alginate-based membrane loaded with bismuth nanoparticles and cetylpyridinium chloride.

OBJECTIVE: To evaluate the antitumor and antimicrobial properties of an alginate-based membrane (ABM) loaded with bismuth lipophilic nanoparticles (BisBAL NPs) and cetylpyridinium chloride (CPC) on clinically isolated bacteria and a pancreatic cancer cell line. MATERIAL AND METHODS: The BisBAL NP-CPC ABM was characterized using optical and scanning electron microscopy (SEM). The antimicrobial potential was measured using the disk-diffusion assay, and antibiofilm activity was determined through the live/dead assay and fluorescence microscopy. The antitumor activity was analyzed on the pancreatic cell line (Panc 03.27) using the MTT assay and live/dead assay with fluorescence microscopy. RESULTS: After a 24-h exposure (37°C, aerobic conditions), 5 µM BisBAL NP reduced the growth of K. pneumoniae by 77.9%, while 2.5 µM BisBAL NP inhibited the growth of Salmonella, E. faecalis and E. faecium by 82.9%, 82.6%, and 78%, respectively (p < 0.0001). The BisBAL NPs-CPC ABM (at a ratio of 10:1; 500 and 50 µM, respectively) inhibited the growth of all isolated bacteria, producing inhibition halos of 9.5, 11.2, 7, and 10.3 mm for K. pneumoniae, Salmonella, E. faecalis, and E. faecium, respectively, in contrast to the 6.5, 9.5, 8.5, and 9.8 mm obtained with 100 µM ceftriaxone (p < 0.0001). The BisBAL NPs-CPC ABM also reduced bacterial biofilms, with 81.4%, 74.5%, 97.1%, and 79.5% inhibition for K. pneumoniae, E. faecium, E. faecalis, and Salmonella, respectively. Furthermore, the BisBAL NPs-CPC ABM decreased Panc 03.27 cell growth by 76%, compared to 18% for drug-free ABM. GEM-ABM reduced tumoral growth by 73%. The live/dead assay confirmed that BisBAL NPs-CPC-ABM and GEM-ABM were cytotoxic for the turmoral Panc 03.27 cells. CONCLUSION: An alginate-based membrane loaded with BisBAL NP and CPC exhibits dual antimicrobial and antitumoral efficacy. Therefore, it could be applied in cancer treatment and to diminish the occurrence of surgical site infections.

Cumulative antitumor effect of bismuth lipophilic nanoparticles and cetylpyridinium chloride in inhibiting the growth of lung cancer.

OBJECTIVE: To determine the combined antitumor effect of bismuth lipophilic nanoparticles (BisBAL NP) and cetylpyridinium chloride (CPC) on human lung tumor cells. MATERIAL AND METHODS: The human lung tumor cells A549 were exposed to 1-100 µM BisBAL NP or CPC, either separately or in a 1:1 combination. Cell viability was measured with the PrestoBlue assay, the LIVE/DEAD assay, and fluorescence microscopy. The integrity and morphology of cellular microtubules were analyzed by immunofluorescence. RESULTS: A 24-h exposure to 1 µM solutions reduced A549 growth with 21.5% for BisBAL NP, 70.5% for CPC, and 92.4% for the combination (p < 0.0001), while a 50 µM BisBAL NP/CPC mixture inhibited cell growth with 99% (p < 0.0001). BisBAL NP-curcumin conjugates were internalized within 30 min of exposure and could be traced within the nucleus of tumor cells within 2 h. BisBAL NP, but not CPC, interfered with microtubule organization, thus interrupting cell replication, similar to the action mechanism of docetaxel. CONCLUSION: The growth inhibition of A549 human tumor cells by BisBAL NP and CPC was cumulative as of 1 µM. The BisBAL NP/CPC combination may constitute an innovative and cost-effective alternative for treating human lung cancer.

Bismuth Lipophilic Nanoparticles (BisBAL NP) Inhibit the Growth of Tumor Cells in a Mouse Melanoma Model.

AIM: The objective of this study was to analyze the antitumor effect of BisBAL NP in a mouse melanoma model. MATERIALS AND METHODS: The antitumor activity of BisBAL NP on murine B16-F10 melanoma cells was determined both in vitro (PrestoBlue cell viability assay and Live/Dead fluorescence) and in vivo, in a mouse model, with the following 15-day treatments: BisBAL NP, negative control (PBS), and cell-death control (docetaxel; DTX). Mouse survival and weight, as well as the tumor volume, were recorded daily during the in vivo study. RESULTS: BisBAL NP were homogeneous in size (mean diameter, 14.7 nm) and bismuth content. In vitro, 0.1 mg/mL BisBAL NP inhibited B16-F10 cell growth stronger (88%) than 0.1 mg/mL DTX (82%) (*p<0.0001). In vivo, tumors in mice treated with BisBAL NP (50 mg/kg/day) or DTX (10 mg/kg/day) were 76% and 85% smaller than the tumors of negative control mice (*p<0.0001). The average weight of mice was 18.1 g and no statistically significant difference was detected among groups during the study. Alopecia was only observed in all DTX-treated mice. The survival rate was 100% for the control and BisBAL NP groups, but one DTX- treated mouse died at the end of the treatment period. The histopathological analysis revealed that exposure to BisBAL NP was cytotoxic for tumor tissue only, without affecting the liver or kidney. CONCLUSION: BisBAL NP decreased the tumor growing in a mouse melanoma model without secondary effects, constituting an innovative low-cost alternative to treat melanoma.

Antimicrobial potential of bismuth lipophilic nanoparticles embedded into chitosan-based membrane.

The objective of this work was to analyze the antimicrobial and antibiofilm activities of bismuth lipophilic nanoparticles (BisBAL NPs) incorporated into chitosan-based membranes. Chitosan-based membranes were homogeneously embedded with BisBAL NPs, confirming the bismuth presence by scanning electron microscopy. The tensile strength of chitosan-based membrane alone or with BisBAL NPs showed similar results as elongation, suggesting that BisBAL NP addition did not affect membrane mechanical properties. Chitosan-based membranes complemented with 100 µM of BisBAL NPs caused a complete inhibition of biofilm formation and a 90-98% growth inhibition of six different oral pathogens. Cytotoxicity studies revealed that 80% of human gingival fibroblasts were viable after a 24-h exposure to the chitosan-based membrane with 100 µM of BisBAL NPs and collagen. Altogether, we conclude that the biological properties of chitosan-based membranes supplemented with BisBAL NPs could be a very interesting option for tissue regeneration.

In vitro evaluation of the antitumor effect of bismuth lipophilic nanoparticles (BisBAL NPs) on breast cancer cells.

AIM: The objective of this study was to evaluate the antitumor activity of lipophilic bismuth nanoparticles (BisBAL NPs) on breast cancer cells. MATERIALS AND METHODS: The effect of varying concentrations of BisBAL NPs was evaluated on human MCF-7 breast cancer cells and on MCF-10A fibrocystic mammary epitheliocytes as noncancer control cells. Cell viability was evaluated with the MTT assay, plasma membrane integrity was analyzed with the calcein AM assay, genotoxicity with the comet assay, and apoptosis with the Annexin V/7-AAD assay. RESULTS: BisBAL NPs were spherical in shape (average diameter, 28 nm) and agglomerated into dense electronic clusters. BisBAL NP induced a dose-dependent growth inhibition. Most importantly, growth inhibition was higher for MCF-7 cells than for MCF-10A cells. At 1 µM BisBAL NP, MCF-7 growth inhibition was 51%, while it was 11% for MCF-10A; at 25 µM BisBAL NP, the growth inhibition was 81% for MCF-7 and 24% for MCF-10A. With respect to mechanisms of action, a 24-hour exposure of 10 and 100 µM BisBAL NP caused loss of cell membrane integrity and fragmentation of tumor cell DNA. BisBAL NPs at 10 µM were genotoxic to and caused apoptosis of breast cancer cells. CONCLUSION: BisBAL NP-induced growth inhibition is dose dependent, and breast cancer cells are more vulnerable than noncancer breast cells. The mechanism of action of BisBAL NPs may include loss of plasma membrane integrity and a genotoxic effect on the genomic DNA of breast cancer cells.

Antimicrobial and antibiofilm activities of MTA supplemented with bismuth lipophilic nanoparticles.

The objective of this work was to determine the antimicrobial and antibiofilm properties of mineral trioxide aggregate (MTA) supplemented with bismuth lipophilic nanoparticles (BisBAL NPs). The antimicrobial activity of the composite MTA-BisBAL NPs was determined by the disk diffusion assay, while antibiofilm activity was analyzed by fluorescence microscopy. The cytotoxicity of MTA-BisBAL NPs was determined on human gingival fibroblasts by optical microscopy and crystal violet staining. MTA-BisBAL NPs inhibited the growth of Enterococcus faecalis, Escherichia coli, and Candida albicans and also detached the biofilm of fluorescent E. faecalis after 24 h of treatment. The addition of BisBAL nanoparticles did not significantly modify the physical properties of MTA, and cytotoxicity was not observed when MTA-BisBAL NPs was added on human gingival fibroblasts. Altogether these results suggest that BisBAL nanoparticles provide antimicrobial and antibiofilm activities to MTA while it retained their biophysical properties without cause side effects on human gingival fibroblasts.

Antimicrobial Effect of Lactobacillus reuteri on Cariogenic Bacteria Streptococcus gordonii, Streptococcus mutans, and Periodontal Diseases Actinomyces naeslundii and Tannerella forsythia.

Lactic acid bacteria (LAB) are well known for their beneficial effects on human health in the intestine and immune system; however, there are few studies on the impact they can generate in oral health. The aim of this study was to test and compare in vitro antimicrobial activity of L. reuteri on pathogenic bacteria involved in the formation of dental caries: S. mutans, S. gordonii, and periodontal disease: A. naeslundii and T. forsythia. Also, we determined the growth kinetics of each bacterium involved in this study. Before determining the antimicrobial action of L. reuteri on cariogenic bacteria and periodontal disease, the behavior and cell development time of each pathogenic bacterium were studied. Once the conditions for good cell growth of each of selected pathogens were established according to their metabolic requirements, maximum exponential growth was determined, this being the reference point for analyzing the development or inhibition by LAB using the Kirby Bauer method. Chlorhexidine 0.12% was positive control. L. reuteri was shown to have an inhibitory effect against S. mutans, followed by T. forsythia and S. gordonii, and a less significant effect against A. naeslundii. Regarding the effect shown by L. reuteri on the two major pathogens, we consider its potential use as a possible functional food in the prevention or treatment of oral diseases.

Evaluación de la filtración corono-apical en la obturación endodóntica cuando se utilizan diferentes métodos de barrera

Este estudio contempla el análisis y comparación del sellado intracoronal en 50 órganos dentarios unirradiculares humanos extraídos, a los que se les realizó tratamiento endodóntico; posteriormente se dividieron en 5 grupos, de 10 cada uno, aplicando en 4 de los grupos los materiales utilizados como método barrera: Cavit G, Ketac Molar, Perma Seal, Single Bond y 1 grupo aparte de control que fue conformado sin ningún tipo de material de barrera. Luego fueron sumergidos en saliva artificial durante 1 mes; transcurrido este tiempo fueron teñidos con azul de metileno al 2% y se procedió a realizar los cortes para su estudio, evaluando la filtración corono apical en 7 secciones de 1mm cada una en toda la longitud radicular, inmediatamente después del material utilizado como método de barrera. Resultados: Se encontró que el adhesivo Single Bond fue el más eficaz como material barrera y que evitó la filtración corono apical.

This study analizes and compares the intracoronal sealing of 50 extracted, single rooted, human dental organs that underwent endodontic treatment; they were divided in 5 groups of 10 each, applying the materials used as barrier method: Cavit G, Ketac Molar, Perma Seal, Single Bond and to 4 groups and leaving one control group without any barrier material. Afterwards they were submerged in artificial saliva for 1 month; after this time they were stained with methylene blue at 2% and proceeded to make the cuts for their study, evaluating crown-apical filtration in 7 sections of 1 mm each along the entire root length starting immediately after the material used as a barrier method. Results: found that the adhesive Single Bond was the most effective as material barrier to avoid crown-apical filtration

Caries dental y los determinantes sociales de la salud en México / Dental caries and social determinants of health in Mexico

La caries dental es una enfermedad multifactorial que representa un problema de salud pública global y nacional. Se conocen los factores de riesgo individual, no así los asociados con su ocurrencia poblacional; no es claro por qué algunos países o regiones presentan mayor prevalencia que otros. Es necesario analizar los determinantes sociales de la salud (DSS) asociados. El objetivo de este estudio fue explorar la asociación entre algunos determinantes poblacionales y la prevalencia de caries dental en la población infantil mexicana. Se realizó un estudio de casos de carácter ecológico cuyas unidades de observación fueron las 32 entidades federativas de la República mexicana. Se realizó un análisis comparativo cualitativo (Qualitative Comparative Analysis, QCA por sus siglas en inglés) usando datos de la Encuesta Nacional de Caries Dental 2001, e información oficial sobre desigualdad en el ingreso (G), producto interno bruto (P), porcentaje de población analfabeta (A), porcentaje de población rural (R), porcentaje de población indígena (I), tasa migratoria neta (L), distribución indicada de sal yodada fluorada (F) por estado. Las configuraciones más frecuentes fueron GpARIlF (17,86 por ciento de los estados); gPariLF (14,29 por ciento); GpARIlf (10,71 por ciento) y gPariLf (7,14 por ciento). Al realizar la reducción a un Benchmark de 0,80, se obtuvo una consistencia de 0,900 y una cobertura de 0,463 con diez configuraciones. A un Benchmark de 0,90 se obtuvo una consistencia de 0,974 y una cobertura de 0,223 con cuatro configuraciones. La desigualdad en el ingreso participa consistentemente en los modelos causales de prevalencia de caries, la distribución de sal yodada y fluorada participa pero negativamente, indicando su presencia como factor protector ante la enfermedad. Se sugiere apoyar acciones que disminuyan la desigualdad en el ingreso, así como el continuar con la política de distribución de sal yodada y fluorada(AU)

Dental caries is a multifactorial disease which represents a public health problem globally and nationally. There are known individual risk factors, not the population associated with its occurrence; it is not clear why some countries or regions have higher prevalence than others. It is necessary to analyze the Social Determinants of Health (SDH) associated. The aim of this study was to explore the association between some population determinants and the prevalence of dental caries in Mexican children. A case study of ecological character whose observation units were the 32 states of Mexico was conducted. A qualitative comparative analysis was conducted, using data from 2001National Survey of Dental Caries, and official data on income inequality (G), gross domestic product (P), percentage of illiterate population (A), percentage of rural population (R), percentage of indigenous population (I), net migration rate (L), indicated distribution of iodized salt fluoridated by state(F). The most common settings were GpARIlF (17.86 percent of the states); gPariLF (14.29 percent); GpARIlf (10.71 percent) and gPariLf (7.14 percent). When reducing a 0.80Benchmark, 0.900 and consistency and 0.463 of coverage were obtained with ten settings. A 0.90 Benchmark, 0.974 of consistency and 0.223 of coverage were obtained with four settings. The income inequality consistently participates in causal models of caries prevalence; distribution of iodized and fluoridated salt was negatively involved indicating its presence as a protective factor against the disease. It is suggested supporting actions to reduce income inequality, as well as to continue the distribution policy of fluoridated and iodized salt(AU)