Visualization of the dentogingival junction using micro-plastination technique.

Plastination has revolutionized the field of anatomy and research by providing biosecurity and enabling the long-term preservation of biological material, ranging from entire bodies to individual organs and even micron sections. The dentogingival junction (DGJ) consists of both epithelial and connective tissues that are closely related to the tooth's mineralized tissues. Cutting-grinding techniques are commonly used to visualize DGJ histology. These techniques exclude enamel from preparations and focus on visualizing hard or soft tissues. To improve the micro-anatomical and histological study of this region, we applied micro-plastination technique to obtain micro-thin slices below 150 µm thick from human and animal samples. The DGJ microanatomy was visualized by applying histological stains to the micro-plastinated slices, highlighting the technique's endogenous autofluorescence capacity identifying periodontal tissues, including dentin, enamel, cementoenamel junction, dentinal tubules, connective tissue, and collagen. Based on our results, we confirm that micro-plastination is a useful technique for visualizing anatomical regions that are difficult to access, such as the DGJ. Micro-plastination can be used as an alternative technique, providing a new approach for its application in anatomical and morphological research protocols.

NOX Inhibition Improves ß-Adrenergic Stimulated Contractility and Intracellular Calcium Handling in the Aged Rat Heart.

Cardiac aging is characterized by alterations in contractility and intracellular calcium ([Ca2+]i) homeostasis. It has been suggested that oxidative stress may be involved in this process. We and others have reported that in cardiomyopathies the NADPH oxidase (NOX)-derived superoxide is increased, with a negative impact on [Ca2+]i and contractility. We tested the hypothesis that in the aged heart, [Ca2+]i handling and contractility are disturbed by NOX-derived superoxide. For this we used adults (≈5 month-old) and aged (20⁻24 month-old) rats. Contractility was evaluated in isolated hearts, challenged with isoproterenol. To assess [Ca2+]i, isolated cardiac myocytes were field-stimulated and [Ca2+]i was monitored with fura-2. Cardiac concentration-response to isoproterenol was depressed in aged compared to adults hearts (p < 0.005), but was restored by NOX inhibitors apocynin and VAS2870. In isolated cardiomyocytes, apocynin increased the amplitude of [Ca2+]i in aged myocytes (p < 0.05). Time-50 [Ca2+]i decay was increased in aged myocytes (p < 0.05) and reduced towards normal by NOX inhibition. In addition, we found that myofilaments Ca2+ sensitivity was reduced in aged myocytes (p < 0.05), and was further reduced by apocynin. NOX2 expression along with NADPH oxidase activity was increased in aged hearts. Phospholamban phosphorylation (Ser16/Thr17) after isoproterenol treatment was reduced in aged hearts compared to adults and was restored by apocynin treatment (p < 0.05). In conclusion, ß-adrenergic-induced contractility was depressed in aged hearts, and NOX inhibition restored back to normal. Moreover, altered Ca2+ handling in aged myocytes was also improved by NOX inhibition. These results suggest a NOX-dependent effect in aged myocytes at the level of Ca2+ handling proteins and myofilaments.

Exposure to fine particulate matter 2.5 from wood combustion smoke causes vascular changes in placenta and reduce fetal size.

During gestation, maternal blood flow to the umbilical cord and placenta increases, facilitating efficient nutrient absorption, waste elimination, and effective gas exchange for the developing fetus. However, the effects of exposure to wood smoke during this period on these processes are unknown. We hypothesize that exposure to PM2.5, primarily sourced from wood combustion for home heating, affects placental vascular morphophysiology and fetal size. We used exposure chambers that received either filtered or unfiltered air. Female rats were exposed to PM2.5 during pre-gestational and/or gestational stages. Twenty-one days post-fertilization, placentas were collected via cesarean section. In these placentas, oxygen diffusion capacity was measured, and the expression of angiogenic factors was analyzed using qPCR and immunohistochemistry. In groups exposed to PM2.5 during pre-gestational and/or gestational stages, a decrease in fetal weight, crown-rump length, theoretical and specific diffusion capacity, and an increase in HIF-1α expression were observed. In groups exposed exclusively to PM2.5 during the pre-gestational stage, there was an increase in the expression of placental genes Flt-1, Kdr, and PIGF. Additionally, in the placental labyrinth region, the expression of angiogenic factors was elevated. Changes in angiogenesis and angiogenic factors reflect adaptations to hypoxia, impacting fetal growth and oxygen supply. In conclusion, this study demonstrates that exposure to PM2.5, emitted from wood smoke, in both pre-gestational and gestational stages, affects fetal development and placental health. This underscores the importance of addressing air pollution in areas with high levels of wood smoke, which poses a significant health risk to pregnant women and their fetuses.

Modified Goldner Trichrome for Non-decalcified Mineralized Tissue Plastinated and Embedded in Resin / Tricrómico de Goldner Modificado para Tejido Mineralizado no Descalcificado Plastinado e Incluido en resina

SUMMARY: Over time, Goldner's trichrome staining has been essential in paraffin soft tissue research. However, its classic application involves prior decalcification, generating disadvantages in the integrity of the samples and the interpretation of results. This study seeks to overcome the limitations associated with decalcification when applying Goldner's trichrome stain with plastic resins. It focuses on detailed visualization of non-decalcified bone and dental samples in animal models. Samples of jaw and tooth from a dog (Canis familiaris) were used, as well as tibia from a rabbit (Oryctolagus cuniculus) with a titanium dental implant and bone graft substitute. Adjustments were made to the original protocol, including a surface treatment prior to staining. Plastination and inclusion in specific plastic resins were part of the process. The microplastinated and stained samples showed optimal quality for optical microscopy. Those from dogs allowed detailed observation of the tooth-periodontal tissue relationship, while those from rabbits revealed a clear differentiation between mineralized and osteoid bone tissue. The staining made it easy to examine the precise interface between soft tissues, bone graft, and implant. The successful adaptation of Goldner's trichrome stain to specimens in plastic resins represents a significant advance in histological investigation of hard tissues. This methodology stands out as an effective tool to evaluate implants and biomaterials in animal models, providing detailed visualization without compromising the integrity of the samples. The combination of histochemistry and plastic resins offers a valuable alternative for microanatomical studies, opening new possibilities in hard tissue research and evaluation of bone structures.

A lo largo del tiempo, la tinción tricrómica de Goldner ha sido esencial en la investigación de tejidos blandos en parafina. Sin embargo, su aplicación clásica conlleva la descalcificación previa, generando desventajas en la integridad de las muestras y la interpretación de resultados. Este estudio busca superar las limitaciones asociadas con la descalcificación al aplicar la tinción tricrómica de Goldner con resinas plásticas. Se enfoca en visualizar detalladamente muestras óseas y dentales no descalcificadas en modelos animales. Se emplearon muestras de mandíbula y diente de perro (Canis familiaris), así como tibia de conejo (Oryctolagus cuniculus) con implante dental de titanio y substituto de injerto óseo. Se realizaron ajustes al protocolo original, incluyendo un tratamiento superficial previo a la tinción. La plastinación y la inclusión en resinas plásticas específicas fueron parte del proceso. Las muestras microplastinadas y teñidas mostraron una calidad óptima para microscopía óptica. Las de perro permitieron la observación detallada de la relación diente-tejido periodontal, mientras que las de conejo revelaron una clara diferenciación entre tejido óseo mineralizado y osteoide. La tinción facilitó examinar la interface precisa entre tejidos blandos, injerto óseo e implante. La adaptación exitosa de la tinción tricrómica de Goldner a muestras en resinas plásticas representa un avance significativo en la investigación histológica de tejidos duros. Esta metodología destaca como una herramienta eficaz para evaluar implantes y biomateriales en modelos animales, brindando una visualización detallada sin comprometer la integridad de las muestras. La combinación de histoquímica y resinas plásticas ofrece una alternativa valiosa para estudios microanatómicos, abriendo nuevas posibilidades en la investigación de tejidos duros y evaluación de estructuras óseas.

Bandas de Hunter-Schreger: propuesta terminológica / Hunter-Schreger bands: terminological propose

Las Bandas de Hunter-Schreger (BHS), son bandas claras y oscuras, que se aprecian en el esmalte debido a la distínta curvatura de los prismas del esmalte, resultan ser ampliamente mencionadas en estudios, tanto odontológicos como antropológicos, mas no se ven reflejadas en Terminologia Histologica. El objetivo del presente trabajo fue realizar un análisis del término BHS, con el fin de proponerlo como nuevo término histológico, y así poder ser incluido en Terminologia Histologica por la Federative International Programme for Anatomical Terminology (FIPAT). Luego del análisis en textos de estudio y publicaciones científicas, proponemos en reemplazo del término BHS, por dos términos: diazone prismatica (diá del griego δι á 'a través de' y del griego zon(e) ζωνη 'faja', 'zona de la tierra') y parazone prismatica (pará gr. 'a lo largo de' y del griego zon(e) ζωνη 'faja', 'zona de la tierra'), definiendo así términos más descriptivos y que no utilizan epónimos, tal como lo establece la Terminología Internacional. Proponer nuevos términos que estén más acorde con los señalado por la International Federation of Associations of Anatomists (IFAA) y la propia terminología, presenta grandes desafíos; un término no sólo es una palabra que hace referencia a una estructura morfológica, sino que también es una unidad del lenguaje, que une a la comunidad morfológica en un solo lenguaje. Por lo cual proponemos que el término sea incluido por la FIPAT en próximas discusiones.

Hunter-Schreger Bands (HSB), are light and dark bands, which can be seen in the enamel due to the different curvature of the enamel prisms, they are widely mentioned in studies, both dental and anthropological, but are not reflected in Terminologia Histologica. The aim of the present work was to carry out an analysis of the HSB term, in order to propose it as a new histological term, and thus be able to be included in Terminologia Histologica by the Federative International Program for Anatomical Terminology (FIPAT). After the analysis in study texts and scientific publications, we propose in replacement of the term HSB, for two terms: diazone prismatica (diá of Greek δι á 'through' and of Greek zon(e) ζωνη 'strip', 'zone of the earth') and parazone prismatica (pará gr. 'along' and from the Greek zon(e) ζωνη 'strip', 'zone of the earth'), thus defining the most descriptive and noneponymous terms, as the International Terminology says. Propose new terms that are more in agreement with those indicated by the International Federation of Associations of Anatomists (IFAA) and the own terminology, presents great answers; A term is not only a word that refers to a morphological structure, but also a unit of language, which unites the morphological community in a single language. So we propose that the term sea included by the FIPAT in the next discussions.