RESUMEN
Calcium silicate cements (CSCs) are the choice materials for vital pulp therapy because of their bioactive properties, promotion of pulp repair, and dentin bridge formation. Despite the significant progress made in understanding CSCs' mechanisms of action, the key events that characterize the early interplay between CSC-dentin-pulp are still poorly understood. To address this gap, a microfluidic device, the "tooth-on-a-chip," which was developed to emulate the biomaterial-dentin-pulp interface, was used to test 1) the effect of CSCs (ProRoot, Biodentine, and TheraCal) on the viability and proliferation of human dental pulp stem cells, 2) variations of pH, and 3) release within the pulp chamber of transforming growth factor-ß (TGFß) as a surrogate of the bioactive dentin matrix molecules. ProRoot significantly increased the extraction of TGFß (P < 0.05) within 24 to 72 h and, along with Biodentine, induced higher cell proliferation (P > 0.05), while TheraCal decreased cell viability and provoked atypical changes in cell morphology. No correlation between TGFß levels and pH was observed. Further, we established a biofilm of Streptococcus mutans on-chip to model the biomaterial-biofilm-dentin interface and conducted a live and dead assay to test the antimicrobial capability of ProRoot in real time. In conclusion, the device allows for direct characterization of the interaction of bioactive dental materials with the dentin-pulp complex on a model of restored tooth while enabling assessment of antibiofilm properties at the interface in real time that was previously unattainable.
Asunto(s)
Materiales Biocompatibles , Dispositivos Laboratorio en un Chip , Materiales Biocompatibles/farmacología , Biopelículas , Compuestos de Calcio/farmacología , Pulpa Dental , Dentina , Combinación de Medicamentos , Humanos , Óxidos , Silicatos/farmacologíaRESUMEN
Indigenous species are less commonly used in laboratory aquatic toxicity tests compared with standard test species due to (1) limited availability lack of requisite information necessary for their acclimation and maintenance under laboratory conditions and (2) lack of information on their sensitivity and the reproducibility of toxicity test results. As part of the Natural Resource Damage Assessment aquatic toxicity program in response to the Deepwater Horizon Oil incident (2010), sensitive life stages of native Gulf of Mexico species were evaluated in laboratory toxicity tests to determine the potential effects of the spill. Fish (n = 5) and invertebrates (n = 2) selected for this program include the following: the Florida pompano (Trachinotus carolinus), red drum (Sciaenops ocellatus), spotted sea trout (Cynoscion nebulosus), cobia (Rachycentron canadum), red porgy (Pagrus pagrus), blue crab (Callinectes sapidus), and the common moon jellyfish (Aurelia aurita). Initially in the program, to establish part of the background information, acute tests with reference toxicants (CdCl2, KCl, CuSO4) were performed with each species to establish data on intraspecies variability and test precision as well as identify other factors that may affect toxicity results. Median lethal concentration (LC50) values were calculated for each acute toxicity test with average LC50 values ranging from 248 to 862 mg/L for fish exposures to potassium chloride. Variability between test results was determined for each species by calculating the coefficient of variation (%CV) based on LC50 values. CVs ranged from 11.2 % for pompano (96-h LC50 value) to 74.8 % for red porgy 24-h tests. Cadmium chloride acute toxicity tests with the jellyfish A. aurita had the lowest overall CV of 3.6 %. By understanding acute toxicity to these native organisms from a compound with known toxicity ranges and the variability in test results, acute tests with nonstandard species can be better interpreted and used appropriately when determining risk.
Asunto(s)
Organismos Acuáticos/fisiología , Pruebas de Toxicidad/normas , Contaminantes Químicos del Agua/toxicidad , Animales , Monitoreo del Ambiente/métodos , Peces , Golfo de México , InvertebradosRESUMEN
The potential for the Deepwater Horizon MC-252 oil incident to affect ecosystems in the Gulf of Mexico (GOM) was evaluated using Americamysis bahia, Menidia beryllina and Vibrio fischeri (Microtox® assay). Organisms were exposed to GOM water samples collected in May-December 2010. Samples were collected where oil was visibly present on the water surface or the presence of hydrocarbons at depth was indicated by fluorescence data or reduced dissolved oxygen. Toxicity tests were conducted using water-accommodated fractions (WAFs), and oil-in-water dispersions (OWDs). Water samples collected from May to June 2010 were used for screening tests, with OWD samples slightly more acutely toxic than WAFs. Water samples collected in July through December 2010 were subjected to definitive acute testing with both species. In A. bahia tests, total PAH concentrations for OWD exposures ranged from non-detect to 23.0 µg L(-1), while WAF exposures ranged from non-detect to 1.88 µg L(-1). Mortality was >20% in five OWD exposures with A. bahia and three of the WAF definitive tests. Total PAH concentrations were lower for M. beryllina tests, ranging from non-detect to 0.64 µg L(-1) and non-detect to 0.17 µg L(-1) for OWD and WAF exposures, respectively. Only tests from two water samples in both the WAFs and OWDs exhibited >20% mortality to M. beryllina. Microtox® assays showed stimulatory and inhibitory responses with no relationship with PAH exposure concentrations. Most mortality in A. bahia and M. beryllina occurred in water samples collected before the well was capped in July 2010 with a clear decline in mortality associated with a decline in total PAH water concentrations.
Asunto(s)
Biota/efectos de los fármacos , Hidrocarburos/toxicidad , Contaminación por Petróleo/efectos adversos , Agua de Mar/química , Contaminantes Químicos del Agua/toxicidad , Aliivibrio fischeri/efectos de los fármacos , Animales , Crustáceos/efectos de los fármacos , Golfo de México , Hidrocarburos/análisis , Contaminación por Petróleo/análisis , Smegmamorpha/crecimiento & desarrollo , Pruebas de Toxicidad , Contaminantes Químicos del Agua/análisisRESUMEN
AIM: To evaluate the effect of four tooth storage temperature-based methods on quality of RNA obtained from cells retrieved from human dental pulps and human pre-dentine. METHODOLOGY: RNA was isolated from dental pulp tissue and from cells retrieved by scraping the pre-dentine of freshly extracted human third molars (n = 15) using TRIzol(®) reagent. Teeth were randomly assigned to the following temperature conditions: immediate RNA isolation after tooth extraction, liquid nitrogen (24 h), -80 °C (24 h), 20 °C (24 h) and 4 °C (6 h). RNA integrity was checked by the density of 28S and 18S ribosomal RNA. RT-PCR was used to analyse the expression of odontoblast makers (DSPP, DMP1 and MEPE) and the housekeeping gene GAPDH. RESULTS: All experimental conditions evaluated preserved RNA integrity. The three odontoblastic markers were amplified from the pulp tissue and from the cells associated with pre-dentine. CONCLUSION: The four storage options allowed RNA isolation for RT-PCR analysis. These findings may facilitate the use of clinically derived human dental pulp and odontoblasts for endodontic research.
Asunto(s)
Criopreservación/métodos , Odontoblastos/citología , ARN/análisis , Conservación de Tejido/métodos , Adolescente , Adulto , Pulpa Dental/citología , Dentina/citología , Electroforesis en Gel de Agar , Proteínas de la Matriz Extracelular/análisis , Glicoproteínas/análisis , Humanos , Fosfoproteínas/análisis , ARN Ribosómico 18S/análisis , ARN Ribosómico 28S/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sialoglicoproteínas/análisis , Adulto JovenRESUMEN
OBJECTIVE: The aim of this in vivo study was to evaluate the response of the pulp-dentin complex following application of resin-modified glass-ionomer cement, calcium hydroxide hard-setting cement and EDTA-soluble preparation of dentine matrix proteins (ESDP) in deep cavities prepared in non-human primate teeth. METHODS: Eighteen deep Class V buccal cavities were prepared in premolars of four capuccin monkeys. In Groups 1 and 2, the cavity floor was lined with ESDP or a resin-modified glass-ionomer cement (Vitrebond - 3M ESPE), respectively. In Group 3 (control), the cavity was lined with a hard setting calcium hydroxide cement (Dycal - Dentsply). The cavities were subsequently filled with amalgam. After 6 months, the animals were sacrificed and the teeth were prepared for microscopic assessment. Six-micron thick serial sections were stained with H/E, Masson's trichrome and Brown & Brenn techniques. RESULTS: No inflammatory pulpal response was observed for all experimental and control Groups. However, the amount of reactionary dentin deposition differed between groups in the rank order ESDP (Group 1) > calcium hydroxide (Group 3) > resin-modified glass-ionomer (Group 2). These differences were statistically significant. CONCLUSIONS: All materials were biocompatible when applied in deep cavities. ESDP stimulated higher deposition of reactionary dentin matrix than Vitrebond and Dycal.
Asunto(s)
Caries Dental/terapia , Recubrimiento de la Cavidad Dental , Pulpa Dental/patología , Dentina/patología , Dentinogénesis , Animales , Materiales Biocompatibles , Resinas Compuestas , Caries Dental/patología , Restauración Dental Permanente , Cementos de Ionómero Vítreo , Haplorrinos , Modelos Animales , FosfoproteínasRESUMEN
Fifteen infants and children, 11 of whom had clinical brain death and four of whom were comatose, were evaluated with the radionuclide bolus study and electroencephalography. Clinical criteria for brain death included: (1) absence of spontaneous respirations, (2) absence of cephalic reflexes, and (3) unresponsiveness. Results demonstrated complete correlation among clinical examination, EEG, and radionuclide study in 79% of cases. An approach to the evaluation of the infant or child with possible brain death is outlined utilizing serial examinations, radionuclide bolus study, and electroencephalography. The radionuclide bolus study appears to be a safe, rapid, portable technique which can be used for this purpose in infants and children.