Statistical analysis of shrinkage levels of human brain slices preserved by sheet plastination technique with polyester resin / Análisis estadístico de los niveles de retracción de cortes de cerebro humano conservados mediante la técnica de plastinación de cortes con resina poliéster

Plastination is currently the most important anatomical preservation technique due to the possibility of preserving bodies and organs for an indefinite period, in a dry and biosecure form, while preserving the morphological characteristics of the tissues. However, the shrinkage of the samples is also part of the plastination, perhaps becoming one of its few disadvantages. This paper presents the shrinkage caused by the classic technique of sheet plastination with polyester resin (Biodur® P40) in human brain slices, with the aim of statistically establishing the percentages of tissue shrinkage caused by this plastination protocol.

La plastinación es actualmente la técnica de preservación anatómica más importante debido a la posibilidad de preservar los cuerpos y órganos por un período indefinido, en forma seca y biosegura, al tiempo que preserva las características morfológicas de los tejidos. Sin embargo, la retracción de las muestras también es parte de la plastinación, quizás convirtiéndose en una de sus pocas desventajas. Este artículo presenta la retracción causada por la técnica clásica de plastinación de cortes con resina poliéster (Biodur® P40) en cortes de cerebro humano, con el objetivo de establecer estadísticamente los porcentajes de retracción de tejidos causados por este protocolo de plastinación.

Deplastination: Preservation of Histological Structures and its Anticipated Role in the Field of Histopathology.

Deplastination is the process of reversing plastination such that a plastinated specimen can be reverted to its raw nature. This would enable its use in the field of histopathology. The present study aims to ascertain if deplastinates can be used for histopathological studies after a time period. Tissue samples were taken from patients undergoing maxillofacial surgeries for oral carcinomas after obtaining written informed consent. The 12 specimens obtained were divided into two groups. One set of tissues was processed for paraffin embedding after 10% formalin fixation. The other set was plastinated by S10 silicon plastination. After 3 months, the plastinates were deplastinated using sodium methoxide and processed for routine hematoxylin and eosin staining, similar to the formalin fixed specimens. The slides were quantitatively assessed on parameters like tissue architecture, staining property, and intracellular structure. In addition, the slides were qualitatively evaluated by a pathologist who was blinded to the mode of preservation to see if identification of pathological features was possible on a deplastinated slide. The formalin preserved specimens and deplastinated tissue slides compared closely in all three parameters tested with the need to identify the endpoint of deplastination. Qualitatively, deplastination did not hamper identification of tissue pathology. Deplastination increases the scope of a stored plastinate by allowing histological studies in the future without the need for any preservatives or special storage equipment. It preserves structure and maintains tissue pathology. An improved method of ensuring the endpoint of deplastination needs to be identified. Clin. Anat. 32:108-112, 2019. © 2019 Wiley Periodicals, Inc.

FIB-SEM of mouse nervous tissue: Fast and slow sample preparation.

Focused ion beam-scanning electron microscopy (FIB-SEM) has become a widely used technique in life sciences. To achieve the best data quality, sample preparation is important and has to be adapted to the specimen and the specific application. Here we illustrate three preparation procedures for mouse nervous tissue: First, the use of high-pressure freezing followed by direct imaging of vitrified tissue without any staining in the FIB-SEM under cryo-conditions as direct and fast procedure. Second, a slow procedure involving freeze substitution of frozen samples combined with additional staining for enhanced contrast and plastic embedding. Third, a fast preparation applying microwave-assisted chemical fixation and processing for resin embedding. All three methods of sample preparation are suitable for obtaining data stacks by FIB-SEM acquisition and 3D reconstruction.

Innovative, Simple Models for Teaching Neuroanatomy Using the Elnady Technique.

Plastination is a valuable tool for the teaching of neuroanatomy. However, the high cost of the process and the complexity of sheet plastination for brain slices remains a challenge. This article describes an innovative, simple, and inexpensive method, called the Elnady Technique, to develop brain slices of various domestic animals. The slices are either enveloped in lamination sheets using an electric iron, or enveloped in transparent plastic using an impulse sealer. This fast, effortless process results in realistic, durable, odorless, soft, flexible slices. The models provide accurate three-dimensional (3D) reference guides for demonstration of neuroanatomical structures that show soft tissue contrast between the gray and white matter. This makes them invaluable for interpretation of clinical imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI). These ethically sourced models can provide a replacement for the killing of animals for practical classes.

Learning anatomy of the foot and ankle using sagittal plastinates: A prospective randomized educational trial.

BACKGROUND: Foot and ankle anatomy is highly complex and presents a considerable educational challenge for the medical student or junior doctor. The successful interpretation of cross-sectional radiological images requires a detailed knowledge of anatomy and spatial relationships. Plastic-impregnated cadaveric prosection slices, known as 'sagittal plastinated slices', or 'SPS', are becoming popular as an adjunct to traditional anatomical teaching methods. OBJECTIVES: To compare the impact of SPS versus conventional anatomy teaching resources (dry bones and whole cadaveric feet) on learners' ability to correctly identify structures of the foot and ankle on sagittal MRI images. METHODS: Randomized educational study using sequential exploratory mixed-methods. RESULTS: The intervention group anatomy test scores were a mean of 1.2 higher after the educational intervention, compared to 0.7 for the control group (scores out of 14), but this was not statistically significant (p=0.41). Learners reported that the SPS intervention was most useful to augment and refine their knowledge after a teaching session using conventional resources. CONCLUSION: The qualitative results showed that SPS provide a valuable adjunct to traditional teaching methods in both anatomy and radiology of the foot and ankle, which should be used after teaching with traditional methods.

Conceptos fundamentales del protocolo modificado de plastinación a temperatura ambiente con silicona, con posterior pigmentación, y su aplicación para la conservación de placenta humana / Fundamental concepts of the modified room temperature plastination protocol with silicone, with subsequent pigmentation, and its application for the conservation of human placenta

RESUMEN: El auge experimentado en los últimos años en la aplicación de las técnicas anatómicas para la conservación de muestras anatómicas está directamente relacionado con la necesidad de preservación de los escasos especímenes con que cuentan las instituciones universitarias en relación a aumentar el tiempo de utilización del mismo. En este sentido, la plastinación es la técnica anatómica que más se destaca y que permite preservar por tiempo indeterminado, sin toxicidad, las preparaciones anatómicas. Presentamos el protocolo modificado de plastinación a temperatura ambiente con silicona, desarrollado en el Laboratorio de Plastinación y Técnicas Anatómicas de la Universidad de La Frontera, con el objetivo de aplicarla a la conservación de una placenta humana, la cual posteriormente fue pigmentada para otorgarle un aspecto más cercano a lo real.

SUMMARY: The surge experienced in recent years in the application of anatomical techniques for the conservation of anatomical samples is directly related to the need to preserve the few specimens that university institutions have in relation to increase the time of use of the same. In this sense, the plastination is the anatomical technique that stands out and that allows to preserve indefinitely, without toxicity, the anatomical preparations. We present the modified plastination protocol at room temperature with silicone, developed in the Laboratory of Plastination and Anatomical Techniques of the University of La Frontera, with the aim of applying it to the conservation of a human placenta, which was subsequently pigmented to give it an appearance closer to the real.

Sectional evaluation of anatomic structures in cat (Felis catus) thoracic cavity by computed tomography imaging and silicone plastination methods / Evaluación seccional de estructuras anatómicas de la cavidad torácica en gato (Felis catus) con imágenes de tomografía computada y métodos de plastinación de silicona

It was aimed to determine the anatomical structures in thoracic cavity by computed tomography imaging (CT) and compare the cross sectional images in the same specimens which were plastinated after CT imaging. It was also aimed to obtain 3 dimensional (3D) reconstructions of thoracic anatomical structures. Thoracic organs of 3 adult cats were CT imaged and then plastinated in this study. Specimens were plastinated in the same body position in the CT imaging process. CT images and corresponding plastinated cross sections were compared to each other. Anatomical structures of the thoracic cavity in plastinates were in accordance with CT images. Beside the bony structures, other organs such as esophagus, trachea, heart with related vessels, lungs and thoracic muscles were well defined in CT images and plastinates. Moreover, 3D reconstructed images of anatomical structures of thoracic cavity were acquired well. This study is thought to be beneficial for veterinary surgery and radiology fields as well as veterinary anatomy educations.

El objetivo de este trabajo consistió en determinar las estructuras anatómicas en la cavidad torácica mediante tomografía computarizada (TC) y comparar las imágenes transversales en las mismas muestras, que fueron plastinadas después de la TC. También se pretendía obtener reconstrucciones tridimensionales (3D) de estructuras anatómicas torácicas. Se tomaron imágenes de los órganos torácicos de 3 gatos adultos por TC y luego se plastinaron en este estudio. Las muestras se plastinaron en la misma posición corporal en el proceso de obtención de imágenes TC. Las imágenes de TC y las secciones transversales plastinadas correspondientes se compararon entre sí. Las estructuras anatómicas de la cavidad torácica en los preparados plastinados estaban de acuerdo con las imágenes de CT. Además de las estructuras óseas, otros órganos como el esófago, la tráquea, el corazón con vasos relacionados, los pulmones y los músculos torácicos estaban bien definidos en las imágenes de TC y los plastinados. Por otra parte, se captaron bien las imágenes reconstruidas en 3D de las estructuras anatómicas de la cavidad torácica. Pensamos que este estudio es beneficioso para la cirugía veterinaria y los campos de radiología, así como también para la educación de anatomía veterinaria.

Epoxy sheet plastination on a rabbit head - new faster protocol with Biodur® E12/E1 / Plastinación de cortes con resina epoxi en una cabeza de conejo - nuevo protocolo rápido con Biodur® E12/E1

SUMMARY: Plastination is an anatomical technique of cadaveric preservation that allows the preservation of anatomical pieces indefinitely, in dry and odorless form. It was created in 1978 by Gunther von Hagens, in Heidelberg, Germany. In particular, the sheet plastination technique, with epoxy resin, allows the generation of thin sections of various anatomical regions, allowing an accurate visualization of anatomical structures of difficult access through dissection or cadaveric exploration. The aim of this work was to present a new sheet plastination protocol with Biodur® E12/E1, which is faster in its implementation, applied, for the first time, in a rabbit head.

RESUMEN: La plastinación es una técnica anatómica de preservación cadavérica que permite la conservación de piezas anatómicas indefinidamente, en forma seca e inodora. Fue creada en 1978 por Gunther von Hagens, en Heidelberg, Alemania. En particular, la técnica de plastinación de cortes, con resina epoxi, permite la generación de secciones delgadas de diversas regiones anatómicas, asegurando una visualización precisa de estructuras anatómicas de difícil acceso mediante disección o exploración de cadáveres. El objetivo de este trabajo fue presentar un nuevo protocolo de plastinación de cortes con resina Biodur® E12/E1, más rápido en su implementación, aplicada por primera vez, en una cabeza de conejo.

Clear Resin Casting of Arthropods of Medical Importance for Use in Educational and Outreach Activities.

Arthropod-related morbidity and mortality represent a major threat to human and animal health. An important component of reducing vector-borne diseases and injuries is training the next generation of medical entomologists and educating the public in proper identification of arthropods of medical importance. One challenge of student training and public outreach is achieving a safe mounting technique that allows observation of morphological characteristics, while minimizing damage to specimens that are often difficult to replace. Although resin-embedded specimens are available from commercial retailers, there is a need for a published protocol that allows entomologists to economically create high-quality resin-embedded arthropods for use in teaching and outreach activities. We developed a detailed protocol using readily obtained equipment and supplies for creating resin-embedded arthropods of many species for use in teaching and outreach activities.

Resin-embedded anatomical cross-sections as a teaching adjunct for medical curricula: is this technique an alternative to potting and plastination?

With an ever-expanding use of cross-sectional imaging for diagnostic and therapeutic purposes, there has also been an increase in the need for exposure to such radiological and anatomical views at the undergraduate and postgraduate level to allow for early familiarisation with the relevant anatomy. Cadaveric cross-sections offer an excellent link between the two-dimensional radiological images and the three-dimensional anatomical structures. For such cross-sections to be useful and informative within educational settings, they need to be: (i) safe for students and trainees to handle and (ii) robust enough to withstand repeated handling; as well as (iii) displaying anatomy clearly and accurately. There are various ways in which cross-sections can be prepared and presented; plastinated, potted, vacuum-sealed or unmounted. Each of these approaches has advantages and disadvantages in terms of technical complexity, cost and quality. As an alternative to the above methods and their limitations, we propose the presentation of cadaveric cross-sections in a transparent polyester resin. This technique has been used extensively in craft and artistic industries, yet it is not publicised in anatomy teaching settings. The sections were layered in polyester resin contained within a mould. The set resin required finishing by sanding and polishing. The final cross-sections were safe to handle, durable and maintained excellent anatomical relationships of the contained structures. The transparency of the set resin was water-clear and did not obstruct the visibility of the anatomy. The cost of the process was found to be significantly lower, requiring less infrastructure when compared with alternative methods. The following trivial technical difficulties were noted during the resin-embedding process: trapped air causing organs to float; retained water in the anatomical specimens creating bubbles and discoloration; and microbubbles emerging from the solution affecting the finished surface. However, solutions to these minor limitations have been discussed within the paper with the aim of future proofing this technique. The sections have been used in undergraduate medical teaching for 4 years and they have shown no signs of degradation or discoloration. We believe that this method is a viable and cost-effective alternative to other approaches of displaying cross-sectional cadaveric material and will help students and trainees bridge the gap between the traditional three-dimensional anatomy and two-dimensional images.

The utility of plastinates in court: a case of firearm homicide.

Plastination is a technique renowned for its use in the preservation of human tissues or organs, and is mainly employed in anatomical training and in research regarding various scientific fields. The advantages of this method are related to the natural appearance, absence of odor, and easy-handling of the plastinated products. The use of plastinates in forensic sciences, their potential role in personal identification, and their usefulness in interpretation of post-mortem findings has been described, although literature on this topic is poor. The present paper is the first report of a firearm homicide where the brain of the victim was plastinated and presented in court as documentary evidence. Three dimensional examination of the brain during the trial allowed the judge to directly evaluate the pathway of the projectile and to compare it with the information that was presented based on depositions, post mortem data and police investigations, in a more straightforward manner. The important role played by plastination in the reported case in assisting with the final verdict could be a catalyst to extend the use of this technique to other criminal cases.

Chemical reactivation of fluorescein isothiocyanate immunofluorescence-labeled resin-embedded samples.

Resin embedding is widely used and facilitates microscopic imaging of biological tissues. In contrast, quenching of fluorescence during embedding process hinders the application of resin embedding for imaging of fluorescence-labeled samples. For samples expressing fluorescent proteins, it has been demonstrated that the weakened fluorescence could be recovered by reactivating the fluorophore with alkaline buffer. We extended this idea to immunofluorescence-labeling technology. We showed that the fluorescence of pH-sensitive fluorescein isothiocyanate (FITC) was quenched after resin embedding but reactivated after treating by alkaline buffer. We observed 138.5% fluorescence preservation ratio of reactivated state, sixfold compared with the quenched state in embedding resin, which indicated its application for fluorescence imaging of high signal-to-background ratio. Furthermore, we analyzed the chemical reactivation mechanism of FITC fluorophore. This work would show a way for high-resolution imaging of immunofluorescence-labeled samples embedded in resin.

Practicable methods for histological section thickness measurement in quantitative stereological analyses.

The accuracy of quantitative stereological analysis tools such as the (physical) disector method substantially depends on the precise determination of the thickness of the analyzed histological sections. One conventional method for measurement of histological section thickness is to re-embed the section of interest vertically to its original section plane. The section thickness is then measured in a subsequently prepared histological section of this orthogonally re-embedded sample. However, the orthogonal re-embedding (ORE) technique is quite work- and time-intensive and may produce inaccurate section thickness measurement values due to unintentional slightly oblique (non-orthogonal) positioning of the re-embedded sample-section. Here, an improved ORE method is presented, allowing for determination of the factual section plane angle of the re-embedded section, and correction of measured section thickness values for oblique (non-orthogonal) sectioning. For this, the analyzed section is mounted flat on a foil of known thickness (calibration foil) and both the section and the calibration foil are then vertically (re-)embedded. The section angle of the re-embedded section is then calculated from the deviation of the measured section thickness of the calibration foil and its factual thickness, using basic geometry. To find a practicable, fast, and accurate alternative to ORE, the suitability of spectral reflectance (SR) measurement for determination of plastic section thicknesses was evaluated. Using a commercially available optical reflectometer (F20, Filmetrics®, USA), the thicknesses of 0.5 µm thick semi-thin Epon (glycid ether)-sections and of 1-3 µm thick plastic sections (glycolmethacrylate/ methylmethacrylate, GMA/MMA), as regularly used in physical disector analyses, could precisely be measured within few seconds. Compared to the measured section thicknesses determined by ORE, SR measures displayed less than 1% deviation. Our results prove the applicability of SR to efficiently provide accurate section thickness measurements as a prerequisite for reliable estimates of dependent quantitative stereological parameters.

Use and perceptions of plastination among medical anatomy educators in the United States.

Traditionally, medical schools have maintained collections of tissues/organs to engage students in anatomy. Such collections are often stored in volatile and toxic preservatives. Plastination is an alternative tissue preservation technique in which polymers replace water and lipids resulting in benign, dry, and anatomically authentic specimens. Plastination is used in medical education internationally; however, its use within U.S. medical schools is not widely discussed in the anatomical literature. This study aimed to determine the knowledge, use, and perceptions of plastination as a teaching tool among U.S. anatomy medical educators. A total of 98 medical anatomy educators who fit inclusion criteria and teach allopathic (MD) students and/or osteopathic (DO) students in the United States completed a national survey, representing 77 medical schools across 37 states. Of these, 100% had heard of plastination, 57% correctly defined plastination, but only 39% currently utilize plastinates for anatomy education. The most frequent explanation for nonuse of plastinates was a preference for the dissection experience, followed by lack of resources and negative past experiences related to durability and quality. A majority (75%) of U.S. medical anatomy educators perceived plastination as a good supplement to, but not a replacement for, cadaveric dissection, 19% indicated no curiosity to use plastination or considered it not useful, and 14% expressed ethical concerns. These findings suggest plastinates are more widely used in the United States than reflected by the literature; however, perceptions regarding their utility indicate a dominant theme for their use to supplement, not replace, cadaveric dissection. Clin. Anat, 2017. © 2017 Wiley Periodicals, Inc.

E12 sheet plastination: Techniques and applications.

Plastination is an anatomical technique that consists of replacing the liquids and fat of specimens by reactive polymers through forced impregnation in a vacuum. These are then polymerized to achieve the final result. E12 sheet plastination involves epoxy resin impregnation of thin (2-4 mm) and ultra-thin (<2 mm) tissue sheets, producing dry, transparent, odorless, non-toxic and long-lasting sheets. E12 sheet plastination techniques were reviewed using MEDLINE, EMBASE and SciELO databases, and manual searches. After searching, 616 records were found using the online and manual searches (MEDLINE, n: 207; EMBASE, n: 346; SciELO, n: 44; Manual search: 23). Finally, 96 records were included in this review (after duplicates and articles unrelated to the subject were excluded). The aim of this work was to review the E12 sheet plastination technique, searching for articles concerning views of it, identifying the different variants implemented by researchers since its creation by Gunther von Hagens, and to identify its applications from teaching and research in anatomy to morphological sciences. Clin. Anat. 31:742-756, 2018. © 2017 Wiley Periodicals, Inc.

Evaluation of 3D Additively Manufactured Canine Brain Models for Teaching Veterinary Neuroanatomy.

Physical specimens are essential to the teaching of veterinary anatomy. While fresh and fixed cadavers have long been the medium of choice, plastinated specimens have gained widespread acceptance as adjuncts to dissection materials. Even though the plastination process increases the durability of specimens, these are still derived from animal tissues and require periodic replacement if used by students on a regular basis. This study investigated the use of three-dimensional additively manufactured (3D AM) models (colloquially referred to as 3D-printed models) of the canine brain as a replacement for plastinated or formalin-fixed brains. The models investigated were built based on a micro-MRI of a single canine brain and have numerous practical advantages, such as durability, lower cost over time, and reduction of animal use. The effectiveness of the models was assessed by comparing performance among students who were instructed using either plastinated brains or 3D AM models. This study used propensity score matching to generate similar pairs of students. Pairings were based on gender and initial anatomy performance across two consecutive classes of first-year veterinary students. Students' performance on a practical neuroanatomy exam was compared, and no significant differences were found in scores based on the type of material (3D AM models or plastinated specimens) used for instruction. Students in both groups were equally able to identify neuroanatomical structures on cadaveric material, as well as respond to questions involving application of neuroanatomy knowledge. Therefore, we postulate that 3D AM canine brain models are an acceptable alternative to plastinated specimens in teaching veterinary neuroanatomy.

The error analysis of Lobular and segmental division of right liver by volume measurement.

The aim of this study is to explore the inconsistencies between right liver volume as measured by imaging and the actual anatomical appearance of the right lobe. Five healthy donated livers were studied. The liver slices were obtained with hepatic segments multicolor-infused through the portal vein. In the slices, the lobes were divided by two methods: radiological landmarks and real anatomical boundaries. The areas of the right anterior lobe (RAL) and right posterior lobe (RPL) on each slice were measured using Photoshop CS5 and AutoCAD, and the volumes of the two lobes were calculated. There was no statistically significant difference between the volumes of the RAL or RPL as measured by the radiological landmarks (RL) and anatomical boundaries (AB) methods. However, the curves of the square error value of the RAL and RPL measured using CT showed that the three lowest points were at the cranial, intermediate, and caudal levels. The U- or V-shaped curves of the square error rate of the RAL and RPL revealed that the lowest value is at the intermediate level and the highest at the cranial and caudal levels. On CT images, less accurate landmarks were used to divide the RAL and RPL at the cranial and caudal layers. The measured volumes of hepatic segments VIII and VI would be less than their true values, and the measured volumes of hepatic segments VII and V would be greater than their true values, according to radiological landmarks. Clin. Anat. 30:585-590, 2017. © 2017 Wiley Periodicals, Inc.

Microstructural alterations owing to handling of bovine pericardium to manufacture bioprosthetic heart valves: A potential risk for cusp dehiscence.

INTRODUCTION: Cross-linking and anti-calcification of prosthetic heart valves have been continuously improved to prevent degeneration and calcification. However, non-calcific structural deteriorations such as cuspal dehiscences along the stent still require further analysis. MATERIAL AND METHOD: Based upon the previous analysis of an explanted valve after 7 years, a fresh commercial aortic valve was embedded in poly(methyl methacrylate) (PMMA) and cut into slices to ensure the detailed observation of the assembly and material structures. A pericardial patch embossed to provide the adequate shape of the cusps was investigated after paraffin embedding and appropriate staining. The microstructural damages that occurred during manufacturing process were identified and evaluated by light microscopy, polarized microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RESULTS: The wavy collagen bundles, the key structure of the pericardium patch, were damaged to a great extent at suture sites along the stent and in the compressed areas around the stent post. The fixation of the embossed pericardium patch along the plots of the stent aggravated the microstructural modifications. The damages mainly appeared as the elimination of collagen bundle waviness and delamination between the bundles. CONCLUSION: Considering the modes of failure of the explant, the damages to the collagen bundles may identify the vulnerable sites that play an important role in the cusp dehiscence of heart valve implants. Such information is important to the manufacturers. Recommendations to prevent in vivo cusp dehiscence can therefore be formulated.

Immunolocalization of Proteins in Fission Yeast by Electron Microscopy.

Electron microscopy (EM) immunolocalization of antigens in fission yeast can be accomplished with cells processed by rapid freezing and freeze-substitution followed by embedding in acrylic or methacrylate resins. Microtome sections of embedded cells are collected onto EM grids. Primary antibodies to the antigen of interest, followed by secondary antibodies conjugated to colloidal gold, are allowed to bind to antigens at the surface of these plastic sections. This type of postembed labeling provides information on antigen localization to a resolution of 10-20 nm, depending on the size of the metal particle used, the form of the antibody (Fab vs. complete IgG or IgM), and whether direct or indirect labeling is used. The method has the potential to map macromolecules in three dimensions in a relatively large volume when thin (30-60-nm) serial sections are labeled, imaged, aligned, and modeled to create a representative volume. The biggest challenge of this technique is the necessary compromise between the preservation of cellular ultrastructure and the preservation of antigen reactivity. The protocols described here show how to immunolabel samples for EM and include suggestions for overcoming challenges related to antigen preservation.