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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The public display of plastinates as a challenge to the integrity of anatomy.

Anatomy has been thrust into the public domain by the highly successful public displays of dissected and plastinated human bodies. This is anatomy in modern guise, anatomy as perceived by the general public. If this is the case, the message it is giving the public about the nature of anatomy is that it is an impersonal analysis of the human body of value within a medical and health care environment. While this is in part true, and while it reflects important aspects of anatomy's history, it fails to reflect the humanistic strands within an increasing swathe of contemporary anatomy. These are manifested in growing recognition of the centrality of informed consent in the practice of anatomy, awareness of the personal dimensions and relationships of those whose bodies are being dissected, and manifested in thanksgiving ceremonies involving staff and students. The notion that the bodies undergoing dissection can be students' first teachers and/or patients is gaining ground, another indication of the human dimensions of the anatomical enterprise. Exhibitions such as Body Worlds ignore these dimensions within anatomy by dislocating it from its clinical and relational base. The significance of this is that loss of these dimensions leads to a loss of the human face of anatomy by isolating it from the people whose body bequests made this knowledge possible. What is required is greater transparency and openness in the practices of all who deal with the dead human body, trends that owe much to the writings of scholars from within a range of humanities disciplines as they have responded to the public displays of dissected plastinated bodies. Anatomists have much to learn from these debates.

The impact of Body Worlds on adult visitors' knowledge on human anatomy: A preliminary study.

Body Worlds is an anatomical exhibition that shows human remains to the public. It has been considered controversial since it raises ethical tensions and issues. However, organizers and supporters of Body Worlds have claimed the exhibition is intended to promote visitors' understanding over the human body. Despite these claims, no studies were found that support or refute the hypothesis that a visit to Body Worlds increases the public's objective knowledge on human anatomy. Consequently, the objective of this study was to determine the impact of Body Worlds on anatomical knowledge. We constructed and delivered a questionnaire to both a previsit random sample and a postvisit random sample of visitors of Body Worlds' event Facets of Life, in Berlin. The questionnaire was available in both English and German languages and contained (a) basic sociodemographic questions and (b) a valid and reliable anatomy quiz. The quiz consisted of 16 multiple-choice questions that assessed the ability to identify the location of major anatomical structures on the human body. Average scores achieved on the quiz by the postvisit sample (X¯= 9.08, s = 2.48, n = 164) were significantly higher (unpaired t = 3.3957, P = 0.0008) than those achieved by the previsit sample (X¯= 8.11, s = 2.69, n = 167). Our results suggest that a visit to Body Worlds' event Facets of Life may have a beneficial effect in anatomical knowledge. However, further studies with better empirical designs and fewer limitations are needed to confirm our results.

Plastination in Anatomy Learning: An Experience at Cambridge University.

Due to lack of objective data, the benefits of using plastination in combination with wet dissection in teaching gross anatomy are unknown. The aim of this study was to obtain objective evidence from students regarding the effectiveness of combining plastinated specimens (PS) with an established gross anatomy education program at Cambridge University that uses wet cadaver dissection and small-group tutorials. For a complete academic year, a total of 135 PS were used alongside wet cadaver dissections. The PS were also available for small-group tutorials. An anonymous closed questionnaire, using a 5-point numerical-estimation Likert scale, was used to gather information relating to the effectiveness of the PS. The level of student satisfaction with the combined use of wet dissections and PS was high, although higher (p<.05) for second-year students (98.4%) than for first-year students (95.5%). Students felt the specimens allowed them to see details that were often more difficult to identify in their dissections, for instance nerves. Voluntary use of PS was higher (p<.01) for second-year students (96.9%), who had previously experienced anatomy teaching with cadaver dissection alone, than for first-year students (77.7%). Overall, 97.7% of all students thought that the PS helped them understand and learn anatomy. All students surveyed (100%) recommended the use of PS in the future. Students considered the use of PS in the dissection room combined with wet cadaver dissection to be beneficial when learning anatomy, particularly when combined with their use during small-group tutorials.

Investigation of resins suitable for the preparation of biological sample for 3-D electron microscopy.

In the last two decades, the third-dimension has become a focus of attention in electron microscopy to better understand the interactions within subcellular compartments. Initially, transmission electron tomography (TEM tomography) was introduced to image the cell volume in semi-thin sections (∼ 500 nm). With the introduction of the focused ion beam scanning electron microscope, a new tool, FIB-SEM tomography, became available to image much larger volumes. During TEM tomography and FIB-SEM tomography, the resin section is exposed to a high electron/ion dose such that the stability of the resin embedded biological sample becomes an important issue. The shrinkage of a resin section in each dimension, especially in depth, is a well-known phenomenon. To ensure the dimensional integrity of the final volume of the cell, it is important to assess the properties of the different resins and determine the formulation which has the best stability in the electron/ion beam. Here, eight different resin formulations were examined. The effects of radiation damage were evaluated after different times of TEM irradiation. To get additional information on mass-loss and the physical properties of the resins (stiffness and adhesion), the topography of the irradiated areas was analysed with atomic force microscopy (AFM). Further, the behaviour of the resins was analysed after ion milling of the surface of the sample with different ion currents. In conclusion, two resin formulations, Hard Plus and the mixture of Durcupan/Epon, emerged that were considerably less affected and reasonably stable in the electron/ion beam and thus suitable for the 3-D investigation of biological samples.

Methods of peripheral nerve tissue preparation for second harmonic generation imaging of collagen fibers.

Second harmonic generation (SHG) imaging of the peripheral nerve using multi-photon microscopy is a novel technique with little documentation. It affords the significant possibility of non-destructive imaging of internal nerve anatomy. The nature of nerve tissue, especially its size and viscoelastic properties, present special challenges for microscopy. While nerves are under an innate in situ strain, they retract once dissected, thus distorting microscopic structure. The challenge is to preserve the nerve in its natural strain range to obtain images that most truly reveal its structure. This study examined backscattered SHG images of rat median nerve prepared by several different methods to compare image quality and content. Nerve segments were fixed under strained (constant load or length) and unstrained conditions and imaged as whole nerve as well as plastic (methyl methacrylate) and paraffin embedded sections. These were tested for optimal excitation wavelength, quantitative image contrast, and overall quality. Root mean squared (RMS) contrast proved to be a reliable measure of the level of image contrast perceived by eye. We concluded that images obtained from tissue sections (plastic and paraffin) provided the most accurate and revealing SHG images of peripheral nerve structure. Removing the embedding material prior to imaging significantly improved image quality. Optimal excitation wavelengths were consistent regardless of the preparation method.

Defining the Morphology and Distribution of the Alar Fascia: A Sheet Plastination Investigation.

OBJECTIVES: This study aims to delineate the morphology, integrity, and distribution of the alar fascia using dissection and E12 sheet plastination. This is the first study that employs E12 sheet plastination to investigate the alar fascia and its adjacent potential spaces. METHODS: Twenty-nine manual dissections and 3 sets of E12 sheet plastinations were used to examine the posterior pharyngeal region for the architecture and distribution of the alar fascia. Specimens were examined from the inferior nuchal line to C6. RESULTS: The alar fascia originated as a well-defined midline structure at the level of C1 and could be identified down to C6. There was no evidence of the alar fascia between the inferior nuchal line and the base of the skull. Notably, the alar fascia permitted resistance to manual traction. CONCLUSIONS: E12 sheet plastination allowed for visualization of the alar fascia's superior attachments within the deep cervical region. Resistance to traction suggests that the alar fascia may be more than just a loose fibroareolar matrix. The findings in this study suggest an alternative point of entry into the danger space. Understanding the continuity of this fascial layer is critically important with regard to the pathophysiology of deep neck space infections.

Comparison of CT numbers of organs before and after plastination using standard S-10 technique.

Plastination is the art of preserving biological tissues with curable polymers. Imaging with plastinates offers a unique opportunity for radiographic, anatomical, pathological correlation to elucidate complex anatomical relationships. The aim of this study was to make plastinates from cadavers using the standard S-10 plastination technique and to compare the radiological properties of the tissue before and afterwards to examine the suitability of plastinates as phantoms for planning radiotherapy treatment. An above-diaphragm and a below-diaphragm specimen were obtained from a male and a female cadaver, respectively, and subjected to the standard S-10 plastination technique. CT images were obtained before and after plastination and were compared using Treatment Planning System for anatomical accuracy, volume of organs, and CT numbers. The plastinated specimens obtained were dry, robust, and durable. CT imaging of the plastinated specimens showed better anatomical detail of the organs than the preplastinate. Organ volumes were estimated by contouring the organs' outline in the CT images of the preplastinated and postplastinated specimens, revealing an average shrinkage of 25%. CT numbers were higher in the plastinated specimens except in bones and air-filled cavities such as the maxillary air sinus. Although plastination by the standard S-10 technique preserves anatomical accuracy, it increases the CT numbers of the organs because of the density of silicone, making it unsuitable for radiation dosimetry. Further improvements of the technique could yield more suitable plastinated phantoms.

Microradiographic and histological evaluation of the bone-screw and bone-plate interface of orthodontic miniplates in patients.

OBJECTIVES: To describe the tissue reactions at the bone-titanium interface of orthodontic miniplates in humans. MATERIALS AND METHODS: Forty-two samples, consisting of tissue fragments attached or not to miniplates or their fixation screws, were collected from 24 orthodontic patients treated with miniplate anchorage, at the time of removal of their miniplates. The samples were embedded in methylmethacrylate and cut into undecalcified sections which were submitted to microradiographic analysis. The sections were also stained and examined under ordinary light. RESULTS: Three types of reactions were observed both on the histological sections and on the microradiographs. 1. The majority of the stable miniplates were easy to remove (34/42). The tissue samples collected consisted mainly in mature lamellar bone with some medullary spaces containing blood vessels, 2. two screws were highly osseointegrated and required the surgeon to remove them by trephining (2/42). They were surrounded by bone tissue which extended to the miniplate. The histological features were similar to the previous group, though the bone-screw contact was higher, and 3. in six samples obtained after unstable miniplate removal during the treatment, we observed either some woven bone trabeculae or loose connective tissue, without any histological sign of inflammation. LIMITATIONS AND CONCLUSION: For evident ethical reasons, our data were limited by the size of the tissue fragments and the limited number of patients and variety of clinical presentations. The healing reactions consisted mainly in mature lamellar bone tissue sparsely in contact with the screw or the miniplate, with signs of a moderate remodelling activity.

[THE METHODOLOGICAL BASIS FOR THE PLASTINATION OF BODY SAWCUTS].

The article describes the technique for making transparent lamellar human body slices using the method of plastination with epoxy resin. Different factors influencing the velocity of dehydration and impregnation of body slices were examined, the dependence of transparency of plastinated slices on the refraction coefficient of the epoxy composition was established. Physical and chemical methods for viscosity correction and optical refraction of epoxy resin composition were suggested. It was shown that plastinated slices with the thickness from 3 to 5 mm had the best demonstration characteristics. The technique suggested can be used for producing educational plastinated specimens for topographic anatomy and for clinical anatomical studies.

Alterations of mouse lung tissue dimensions during processing for morphometry: a comparison of methods.

Preservation of original tissue dimensions is an essential prerequisite for morphometric studies. Shrinkage occurring during tissue processing for histology may severely influence the appearance of structures seen under the microscope and stereological calculations. Therefore, shrinkage has to be avoided so that estimates obtained by application of unbiased stereology are indeed unbiased. The present study investigates the alterations of tissue dimensions of mouse lung samples during processing for histology. Different fixatives as well as embedding protocols are considered. Mouse lungs were fixed by instillation of either 4% formalin or a mixture of 1.5% glutaraldehyde/1.5% formaldehyde. Tissue blocks were sampled according to principles of stereology for embedding in paraffin, glycol methacrylate without treatment with osmium tetroxide and uranyl acetate, and glycol methacrylate including treatment with osmium tetroxide and uranyl acetate before dehydration. Shrinkage was investigated by stereological measurements of dimensional changes of tissue cut faces. Results show a shrinkage of the cut face areas of roughly 40% per lung during paraffin embedding, 30% during "simple" glycol methacrylate embedding, and <3% during osmium tetroxide/uranyl acetate/glycol methacrylate embedding. Furthermore, the superiority of the glutaraldehyde-containing fixative regarding shrinkage is demonstrated. In conclusion, the use of a glutaraldehyde-containing fixative and embedding in glycol methacrylate with previous treatment of the samples with osmium tetroxide and uranyl acetate before dehydration is recommended for stereological studies of the mouse lung.