ABSTRACT
Introducción: La implementación de modelos animales para el estudio de los tejidos dentales y periodontales de dientes articulados en sus alvéolos sometidos a altas temperaturas permite el establecimiento de parámetros repetitivos que contribuyen con los procesos de identificación. Objetivo: Describir los cambios radiográficos de los tejidos dentales y periodontales de cerdo (Sus domesticus) sometidos a altas temperaturas. Material y métodos: Se realizó un estudio observacional descriptivo de naturaleza pseudo-experimental in vitro para observar los cambios radiográficos de los tejidos dentales y periodontales en 60 dientes de cerdo doméstico sometidos a altas temperaturas (200, 400, 600, 800 y 1,000 ºC). Resultados: Los tejidos dentales y periodontales estudiados presentan gran resistencia a las altas temperaturas sin variar considerablemente su microestructura, de tal manera que los cambios físicos (estabilidad dimensional, fisuras, grietas y fracturas) que ocurren en la medida que aumenta la temperatura pueden describirse a través de radiografía convencional. Conclusiones: El análisis radiográfico de los dientes articulados en sus respectivos alvéolos se constituye en un mecanismo para determinar la temperatura a la cual estuvo sometido un diente, lo que puede ser empleado durante el proceso de identificación odontológica y documentación de la necropsia médico-legal para el caso de cadáveres o restos humanos quemados, carbonizados e incinerados. El cerdo doméstico (Sus domesticus) se constituye en un modelo animal experimental adecuado para estudiar dichos cambios; sin embargo, se recomienda realizar un estudio en dientes humanos articulados en su respectiva unidad alveolar, para determinar si los hallazgos radiográficos descritos se repiten y son extrapolables.
Introduction: The implementation of animal models for the study of periodontal and dental tissues of teeth articulated into their sockets and subjected to high temperatures allows the establishment of repetitive parameters which might contribute to identification processes. Aim: To describe radiographic changes of pig's (Sus domesticus) periodontal and dental tissues subjected to high temperatures. Material and methods: An in vitro pseudo-experimental, descriptive and observational study was undertaken in order to assess radiological changes of periodontal and dental tissues of 60 domestic pig's teeth which had been subjected to high temperatures (200, 400, 600, 800 and 1,000 ºC). Results: The dental and periodontal tissues subject of this research article presented strong resistance to high temperatures without considerable variation of their micro-structure. Thus, physical changes (dimensional stability, fissures, cracks and fractures) which took place as temperature increased, could be described using a conventional X-ray. Conclusions: Radiographic examination of teeth articulated in their sockets can be established as a mechanism to determine the temperature at which the tooth was subjected. This could be used in processes of dental identification and medical-legal autopsy documentation in cases of burned, carbonized or incinerated human remains. Domestic pigs (Sus domesticus) can be regarded as a suitable experimental animal models to study the aforementioned changes. Nevertheless, a study involving human teeth articulated in their own socket is recommended in order to determine whether the radiographic findings herein described are replicated and can be extrapolated.
ABSTRACT
The process of drug discovery and development requires substantial resources and time. The drug industry has tried to reduce costs by conducting appropriate animal studies together with molecular biological and genetic analyses. Basic science research has been limited to in vitro studies of cellular processes and ex vivo tissue examination using suitable animal models of disease. However, in the past two decades new technologies have been developed that permit the imaging of live animals using radiotracer emission, X-rays, magnetic resonance signals, fluorescence, and bioluminescence. The main objective of this review is to provide an overview of small animal molecular imaging, with a focus on nuclear imaging (single photon emission computed tomography and positron emission tomography). These technologies permit visualization of toxicodynamics as well as toxicity to specific organs by directly monitoring drug accumulation and assessing physiological and/or molecular alterations. Nuclear imaging technology has great potential for improving the efficiency of the drug development process.
Subject(s)
Animals , Drug Discovery , Drug Industry , Electrons , Fluorescence , Magnetic Resonance Spectroscopy , Models, Animal , Molecular Imaging , Tomography, Emission-ComputedABSTRACT
ObjectiveTo evaluate the anticancer activity of 5'-dexoxy-fluorouridine on colon cancer experimental models in BALB/C mice,compared with 5'-fluorouracil,an anticancer agent widely used in clinic,meanwhile,examined the conversion of 5'-Dexoxy-fluorouridine to 5' -fluorouracil in cancer tissues and serum of mouse models.MethodsThe xenografts of mouse colon cancer cell line CT 26 were transplantated to cecum in 60 male BALB/C mice.Three days lated,these mice were divided into 3 groups and intro- peritoneally injected:( 1 ) 5' - dexoxy- fluorouridine 0.1 mg/g,(2) 5' - Fluorouracil 0.02 mg/g,(3)0.9％ sodium chloride 0.4 mL (as a control),respectively.Two and three weeks later,6 mice were sacririced in every group respectively to measure the weight of tumors and bodies,to examine the Hb,RBC,WBC,PLT,AST,ALT,UREA,and CREA in blood.The rest 8 mice in each group were fed generally,and the survival time from operation to natural death was recorded.In addition,14 mice with xenografts of CT 26 about 2 weeks,were divided into 2 groups averagely,5' -dexoxy-fluorouridine 0.1 mg/g and 5' -fluorouracil 0.02 mg/g were intro-peritoneally injected respectively.Fifteen min later,the converted 5' -fluorouracil was detected from the blood and tumor tissues in sacrificed mice.ResultsThe lest tumor average weight was found in the mice injected 5 '-dexoxy-fluorouridine,being (0.07 ± 0.12) g and (0.24g ±0.29) g for the mice sacrificed at 2 and 3 weeks later,respectively.The average survival time for rest mice was ( 32.6 ± 8.9) d.The average tumor weight in 5' - fluorouracil group was (0.74 ± 0.43 ) g and ( 1.13 ±0.75) g at 2 and 3 weeks later,and the average survival time for the rest was (22.8 ±5.9)d,respectively.The average tumor weight in the control group was (0.70 ±0.47) g and ( 1.93 ±0.83) g at 2 and 3 weeks,and the average survival time for the rest was ( 17.5 ± 2.8 ) d.Either the average tumor weight or average survival time in the mice of 5 ' -dexoxy-fluorouridine group was significantly differen from either 5' -fluorouracil group or control (P ＜ 0.05 ).However,there was no significant difference for the numbers of WBC,PLC,Hb,and some function examination of liver and kidney among 3 group mice,besides the loss of weights in 5'-fluorouracil group mice after operation and medicine therapy which was significantly obvious than that in 5' -deoxy-fluorouridine and control groups ( P ＜ 0.05 ).In addition,( 54.71 ± 12.82) μg/g 5' -fluorouracil was detected in xenografts of mice injected 5' -dexoxy-fluorouridine 15 min later,which was the 6.20 folds of 5' -fluorouracil detected in serum from sthe ame group,P ＜0.05.However,( 133.35 ±20.69) μg/m 5'-fluorouracil were detected in serum of mice after 5' -fluorouracil were injected 15 min later,which was the 1.55 folds of 5' -fluorouracil detected in the xenografts from same group ( P ＜ 0.05 ).ConclusionsIn colon cancer tissues of mouse experimental models,5' - dexoxy- fluorouridine could be converted effectively to 5'-fluorouracil,an obvious high concentration being detected in serum of mice than in cancer tissues.The anticancer effect of 5'-dexoxy-fluorouridine on mouse colon cancer models was more effective than 5'-fluorouracil,resulting in a longer survival duration,less side effect and no significant injury on liver and kidney functions.However,the mechanism of 5' -dexoxy-fluorouridine converted to 5' -fluorouracil in cancer tissue is needed further investigation.