Evaluación de la mineralización en mandíbula y diente de trucha arcoíris (Oncorhynchus mykiss) mediante microscopía electrónica de barrido de presión variable acoplada a detector de espectroscopía de rayos X de energía dispersiva / Evaluation of mineralization in jaw and teeth of rainbow trout (Oncorhynchus mykiss) using variable pressure scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy detector

RESUMEN: En salmonicultura se utilizan imágenes de rayos X, para evaluar la columna vertebral y las aletas, pero estas no permiten cuantificar los minerales que constituyen el hueso, para esto se utilizan otras técnicas que son destructivas. La Microscopía Electrónica de Barrido de presión variable (VP SEM) acoplada al detector espectroscopia de rayos X de energía dispersiva (EDX) acoplado, nos permite analizar la microestructura y a la vez determinar elementos químicos, porcentaje y distribución presentes en puntos específicos en una muestra. Se utilizaron 5 truchas control y 5 con deformidad mandibular, de agua dulce en etapa de smolt, se analizó la estructura y mineralización del hueso, se eligieron en promedio 6 puntos de cuantificación por región de interés y se analizaron mediante Microscopía Electrónica de Barrido (VP SEM-EDX). Los datos obtenidos muestran porcentaje en masa de Ca promedio en hueso articular de truchas fueron de 8.07 % y de 14.48 % en truchas con deformidad mandibular y control respectivamente y el porcentaje en masa promedio de P es de 4.07 % y 7.60 %, en truchas con deformidad mandibular y control respectivamente. Se identificó además otros elementos presentes en la muestra como Mg, Na, C, O, N, S, F, Zn, Al y Fe, con especial interés en el aumento de carbono en las muestras analizadas con deformidad mandibular y la presencia de aluminio en todas las muestras. La Técnica de VP SEM-EDX, permite evaluar de forma directa, sin destrucción de la muestra y con una preparación mínima de la muestra. En el hueso, la aplicación más frecuente de SEM-EDX es la medición del contenido de Ca y P y la relación que existe entre estos elementos Ca/P, en la muestra. Paralelamente la técnica nos permite la detección de otros microelementos provenientes del agua o de la alimentación y que eventualmente pueden provocar alteraciones en los peces, confirmando la hipótesis que el microanálisis elemental tiene utilidad para la salmonicultura.

SUMMARY: In salmon farming systems, X-ray images are used to evaluate the spine and fins, but these do not allow quantifying the minerals that make up the bone, for different techniques that are destructive are used. Variable Pressure Scanning Electron Microscopy (VP SEM) coupled to an Energy Dispersive X-ray spectroscopy detector (EDX), allows us to analyze the microstructure and at the same time determine chemical elements, percentages, and distribution present at specific points in a sample. Five control and five jaw deformity trout, from freshwater and in the smolt stage were used. The structure and mineralization of the bone were analyzed, an average six quantification points were chosen per region of interest (ROI) and then they were analyzed by Scanning Electron Microscopy (VP SEM-EDX). The data obtained have shown the average mass percentage of calcium in trout joint bone was 8.07 % and 14.48 % in jaw deformity and control trout, respectively; and the average mass percentage of phosphorus is 4.07 % and 7.60 %, in jaw deformity and control trout, respectively. Other elements present in the sample were also identified, such as magnesium, sodium, carbon, oxygen, nitrogen, sulphur, fluorine, zinc, aluminium, and iron, with special interest the increase of carbon in the analyzed samples with mandibular deformity and the presence of aluminum in all samples. The VP SEM-EDX Technique allows direct evaluation, without destruction of the sample and with minimal sample preparation. In bone, the most frequent application of SEM-EDX is the measurement of the content of calcium (Ca) and phosphorus (P) and the relationship that exists between these elements, calcium/phosphorus (Ca/P), in the sample. At the same time, the technique allows us to detect other microelements from water or food that can eventually cause alterations in fish, confirming the hypothesis that elemental microanalysis is useful for salmon farming.

DNA extraction from bones and teeth using AutoMate Express forensic DNA extraction system / 法医学杂志

OBJECTIVE@#To explore a new method in order to extract DNA from bones and teeth automatically.@*METHODS@#Samples of 33 bones and 15 teeth were acquired by freeze-mill method and manual method, respectively. DNA materials were extracted and quantified from the triturated samples by AutoMate Express forensic DNA extraction system.@*RESULTS@#DNA extraction from bones and teeth were completed in 3 hours using the AutoMate Express forensic DNA extraction system. There was no statistical difference between the two methods in the DNA concentration of bones. Both bones and teeth got the good STR typing by freeze-mill method, and the DNA concentration of teeth was higher than those by manual method.@*CONCLUSION@#AutoMate Express forensic DNA extraction system is a new method to extract DNA from bones and teeth, which can be applied in forensic practice.

The cariogenic dental biofilm: good, bad or just something to control?

This paper discusses the role of dental biofilm and adjunctive therapies in the management of dental caries. Dental biofilm is a site of bacterial proliferation and growth, in addition to being a location of acid production. It also serves as a reservoir for calcium exchange between the tooth and saliva. The salivary pellicle, a protein-rich biofilm layer, regulates the reaction between tooth surface, saliva and erosive acids. The protective effects of this pellicle on enamel are well established. However, understanding the effects of the pellicle/biofilm interaction in protecting dentin from erosive conditions requires further research. Saliva interacts with the biofilm, and is important in reducing the cariogenic effects of dental plaque as acidogenic bacteria consume fermentable carbohydrates producing acids that may result in tooth demineralization. Adequate supplies of healthy saliva can provide ingredients for successful remineralization. Strategies for managing the cariogenic biofilm are discussed with emphasis on the effectiveness of over-the-counter (OTC) products. However, since many toothpaste components have been altered recently, new clinical trials may be required for true validation of product effectiveness. A new generation of calcium-based remineralizing technologies may offer the ability to reverse the effects of demineralization. Nevertheless, remineralization is a microscopic subsurface phenomenon, and it will not macroscopically replace tooth structure lost in a cavitated lesion. Optimal management of cavitations requires early detection. This, coupled with advances in adhesive restorative materials and microsurgical technique, will allow the tooth to be restored with minimal destruction to nearby healthy tissue.

A reviewing for profiling of highly degraded remains / 法医学杂志

It's always a challenge to type from highly degraded biological remains. PCR-based STR genotyping is helpful and valuable for such degraded samples like bones, teeth et al, but the typing results are sometimes unstable or wrong. Here the methods for solving the problems and improving reproducibility are reviewed.

Diente de bovino, una alternativa a los dientes humanos como sustrato en investigación: revisión bibliográfica / Bovine teeth, an alternative to the human teeth in research: bibliographic review

Como consecuencia del auge de la Odontología preventiva y conservadora es que cada vez se cuenta con menos dientes humanos extraidos para los estudios odontológicos. Surge la necesidad de buscar dientes que sean homologables a los dientes humanos. Según numerosas investigaciones los dientes de bovino serían los de primera selección por ser de fácil obtención y por tener muy pocas o ninguna diferencia tanto a nivel macro como microscópico con respecto a los dientes humanos. Esta publicación pretende analizar las características que justifican el uso de dientes de bovino en investigación, como también evidenciar similitudes y/o diferencias que existen entre el esmalte y dentina humano y de bovino, tanto a nivel químico como de sus estructuras macro y microscópica, en investigaciones realizadas a nivel nacional como internacional. Como conclusión, podemos decir que tanto al MEB como la microscopía óptica, el esmalte y dentina humano y bovino presentan las mismas estructuras. En relación a la adhesión de la resina compuesta a esmalte humano y bovino, no existen diferencias estadísticamente significativas, observándose un ligero aumento en la adhesión a esmalte de bovino que a esmalte humano. Esto último es contrario a resultados obtenidos por otros investigadores. A pesar de esto, ambos tipos de esmaltes serían esencialmente comparables en lo referente a la adhesión. Al análisis químico comparativo del esmalte humano y bovino grabado y no grabado, existen diferencias que pueden justificar la mayor adhesión de las resinas compuestas al esmalte bovino. Se observa una disminución importante en el porcentaje de algunos elementos cuando se somete el esmalte a la técnica de grabado ácido, especialmente del ion calcio. Las mayores diferencias en el análisis comparativo del esmalte humano y bovino sin grabado ácido se observa en el ion zinc. El tiempo de grabado ácido de 30 seg. en diente bovino demostró ser el más efectivo ya que presentó los mejores valores en cuanto a la resistencia a la fuerza de cizallamiento en comparación con los tiempos de 15, 60 y 0 seg. respectivamente

Histochemical detection of sugar residues in lizard teeth (Liolaemus gravenhorsti): a lectin-binding study

The structural diversity of the many oligosaccharide chains of surface glycoconjugates renders them likely candidates for modulators of cell-interactions, cellular movements, differentiation, and cellular recognition. A selection of different lectins was used to investigate the appearance of cellular distribution and changes in sugar residues during tooth development in the polyphyodont lizard, Liolaemus gravenhorsti. Lectins from three groups were used: (1) N-acetylgalactosamine specificity: BS-1, PNA, RCA-120; (2) N-acetylglucosamine specificity: ECA; and (3) fucose specificity: UEA 1 and LTA.. Digital images were processed using Scion Image. Grayscale graphics in each image were obtained. The lectins used showed a strong, wide distribution of the L-fucose and N-acetylgalactosamine at the cell surface and in the cytoplasm of multinucleate odontoclast cell, while mononuclear odontoclast cells showed no binding, suggesting some roles that the residues sugar might play in the resorption of dentine or with multinucleation of odontoclast after the attachment to the dentine surface in this polyphyodont species. Further studies must be planned to determine the specific identities of these glycoconjugates,and to elucidate the roles played by these sugar residues in the complex processes related to odontogenesis in polyphyodont species.