The authors thank Lisa Pichl for excellent technical assistance.

<ol>
	<li>Aigner, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transgenic+pigs+as+models+for+translational+biomedical+research.">Transgenic pigs as models for translational biomedical research.</a> J Mol. Med. 88, 653-664 (2010).</li><li>Blutke, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Munich+MIDY+Pig+Biobank:+A+unique+resource+for+studying+organ+crosstalk+in+diabetes.">The Munich MIDY Pig Biobank: A unique resource for studying organ crosstalk in diabetes.</a> Mol Metab. 6, 931-940 (2017).</li><li>Klymiuk, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dystrophin-deficient+pigs+provide+new+insights+into+the+hierarchy+of+physiological+derangements+of+dystrophic+muscle.">Dystrophin-deficient pigs provide new insights into the hierarchy of physiological derangements of dystrophic muscle.</a> Hum Mol Genet. 22, 4368-4382 (2013).</li><li>Klymiuk, N., Seeliger, F., Bohlooly, Y. M., Blutke, A., Rudmann, D. G., Wolf, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tailored+pig+models+for+preclinical+efficacy+and+safety+testing+of+targeted+therapies.">Tailored pig models for preclinical efficacy and safety testing of targeted therapies.</a> Toxicol Pathol. 44, 346-357 (2016).</li><li>Renner, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Permanent+neonatal+diabetes+in+INSC94Y+transgenic+pigs.">Permanent neonatal diabetes in INSC94Y transgenic pigs.</a> Diabetes. 62, 1505-1511 (2013).</li><li>Abbott, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inside+the+first+pig+biobank.">Inside the first pig biobank.</a> Nature. 519, 397-398 (2015).</li><li>Albl, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+sampling+guides+for+porcine+biomedical+models.">Tissue sampling guides for porcine biomedical models.</a> Toxicol Pathol. 44, 414-420 (2016).</li><li>Gundersen, H. J. G., Mirabile, R., Brown, D., Boyce, R. W., Haschek, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereological+principles+and+sampling+procedures+for+toxicologic+pathologists.">Stereological principles and sampling procedures for toxicologic pathologists.</a> Haschek and Rousseaux's Handbook of Toxicologic Pathology. , 215-286 (2013).</li><li>Howard, C. V., Reed, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Unbiased Stereology: Three-Dimensional Measurement in Microscopy. , 1-277 (2005).</li><li>Mattfeldt, T., Mall, G., Gharehbaghi, H., Moller, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+surface+area+and+length+with+the+orientator.">Estimation of surface area and length with the orientator.</a> J Microsc. 159, 301-317 (1990).</li><li>Nyengaard, J. R., Gundersen, H. J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+isector:+A+simple+and+direct+method+for+generating+isotropic,+uniform+random+sections+from+small+specimens.">The isector: A simple and direct method for generating isotropic, uniform random sections from small specimens.</a> J Microsc. 165, 427-431 (1992).</li><li>Tschanz, S., Schneider, J. P., Knudsen, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design-based+stereology:+Planning,+volumetry+and+sampling+are+crucial+steps+for+a+successful+study.">Design-based stereology: Planning, volumetry and sampling are crucial steps for a successful study.</a> Ann Anat. 196, 3-11 (2014).</li><li>Dorph-Petersen, K. A., Nyengaard, J. R., Gundersen, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+shrinkage+and+unbiased+stereological+estimation+of+particle+number+and+size.">Tissue shrinkage and unbiased stereological estimation of particle number and size.</a> J Microsc. 204, 232-246 (2001).</li><li>Mattfeldt, T., Doerr, W., Leonhardt, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereologische+Methoden+in+der+Pathologie+[Stereologic+methods+in+pathology].">Stereologische Methoden in der Pathologie [Stereologic methods in pathology].</a> Normale und pathologische Anatomie. , (1990).</li><li>Gundersen, H. J., Jensen, E. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+efficiency+of+systematic+sampling+in+stereology+and+its+prediction.">The efficiency of systematic sampling in stereology and its prediction.</a> J Microsc. 147, 229-263 (1987).</li><li>Scherle, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+for+volumetry+of+organs+in+quantitative+stereology.">A simple method for volumetry of organs in quantitative stereology.</a> Mikroskopie. 26, 57-60 (1970).</li><li>Nielsen, K. K., Andersen, C. B., Kromann-Andersen, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparison+between+the+effects+of+paraffin+and+plastic+embedding+of+the+normal+and+obstructed+minipig+detrusor+muscle+using+the+optical+disector.">A comparison between the effects of paraffin and plastic embedding of the normal and obstructed minipig detrusor muscle using the optical disector.</a> J Urol. 154, 2170-2173 (1995).</li><li>Schneider, J. P., Ochs, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alterations+of+mouse+lung+tissue+dimensions+during+processing+for+morphometry:+a+comparison+of+methods.">Alterations of mouse lung tissue dimensions during processing for morphometry: a comparison of methods.</a> Am J Physiol Lung Cell Mol Physiol. 306, L341-L350 (2014).</li><li>von Bartheld, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distribution+of+particles+in+the+z-axis+of+tissue+sections:+Relevance+for+counting+methods.">Distribution of particles in the z-axis of tissue sections: Relevance for counting methods.</a> NeuroQuantology. 10, 66-75 (2012).</li><li>Baddeley, A. J., Gundersen, H. J., Cruz-Orive, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+surface+area+from+vertical+sections.">Estimation of surface area from vertical sections.</a> J microsc. 142, 259-276 (1986).</li><li>Blutke, A., Schneider, M. R., Wolf, E., Wanke, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+hormone+(GH)-transgenic+insulin-like+growth+factor+1+(IGF1)-deficient+mice+allow+dissociation+of+excess+GH+and+IGF1+effects+on+glomerular+and+tubular+growth.">Growth hormone (GH)-transgenic insulin-like growth factor 1 (IGF1)-deficient mice allow dissociation of excess GH and IGF1 effects on glomerular and tubular growth.</a> Physiol Rep. 4, e12709 (2016).</li><li>Hermanns, W., Liebig, K., Schulz, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postembedding+immunohistochemical+demonstration+of+antigen+in+experimental+polyarthritis+using+plastic+embedded+whole+joints.">Postembedding immunohistochemical demonstration of antigen in experimental polyarthritis using plastic embedded whole joints.</a> Histochemistry. 73, 439-446 (1981).</li><li>Böck, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Romeis Mikroskopische Technik. , 1-697 (1989).</li><li>Suvarna, K. S., Layton, C., Bancroft, J. D., Suvarna, K. S., Layton, C., Bancroft, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bancroft's theory and practice of histological techniques. , 1-654 (2013).</li><li>Knust, J., Ochs, M., Gundersen, H. J., Nyengaard, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereological+estimates+of+alveolar+number+and+size+and+capillary+length+and+surface+area+in+mice+lungs.">Stereological estimates of alveolar number and size and capillary length and surface area in mice lungs.</a> Anat Rec (Hoboken). 292, 113-122 (2009).</li><li>Nyengaard, J. R., Gundersen, H. J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sampling+for+stereology+in+lungs.">Sampling for stereology in lungs.</a> Eur Respir Rev. 15, 107-114 (2006).</li><li>Junatas, K. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereological+analysis+of+size+and+density+of+hepatocytes+in+the+porcine+liver.">Stereological analysis of size and density of hepatocytes in the porcine liver.</a> J Anat. 230, 575-588 (2017).</li></ol>

The authors have nothing to disclose.

Generation of biobank sample collections from porcine animal models requires robust techniques and protocols for the determination of organ/tissue volumes, the reproducible generation of representative, redundant tissue samples suitable for a broad range of different analysis methods, and for randomization of the orientation of sample sections for quantitative stereological analyses. The methods described in the present article are adapted to the sizes of porcine organs and tissues, and have been developed to effectively...

In translational medicine, pigs are increasingly common for use as large animal models1,2,3,4,5, due to several advantageous similarities between the porcine and human anatomy and physiology, and the availability of established molecular biological methods allowing for generation of tailored, genetically modified pig models for a wide range of disease conditions1,4.
However, compared to rodent models, the number of animals of a respective pig model that can be provided for experiments at any time is limited. This is due to the porcine generation interval of approximately one year, and the financial and time-intensive efforts required for the generation of porcine models and animal husbandry. Therefore, individual animals of a porcine model, as well as the samples that can be generated from these pigs, are very valuable, particularly if genetically modified porcine models and/or long-term experimental issues (e.g., late complications of chronic diseases) are examined in aged individuals2,6,7.
In the course of any study, performance of additional analyses which had not been scheduled in the initial experimental design of the study might later turn out to be relevant, e.g., to address distinct questions arising from previously discovered unexpected findings. If suitable samples for such additional experiments are not available, disproportionally high cost and time-intensive expenditures might be necessary to generate additional pigs and tissue samples. To be prepared for such eventualities, generation of biobank collections of conserved back-up samples of different organs, tissues, or bio-liquids, quantitatively and qualitatively suitable for a broad range of subsequent analyses, is considered an important approach2,6,7. Deriving optimal benefits from a porcine animal model, the availability of adequate biobank samples also offers the unique possibility to perform a broad spectrum of different analysis methods on identical sample materials on a multi-organ level in the very same individual animals, e.g., by distribution of samples to scientists of different working-groups organized in a research network2,6,7. Additionally, the &#39;&#39;forward-looking&#39;&#39; sampling strategy in biobanking also contributes to a reduction of the number of animals needed in a study. The advantages of porcine model biobanking have recently been demonstrated in a multi-organ, multiomics study, examining organ cross talk in a genetically modified porcine model of long-term diabetes mellitus, using specimens from the Munich MIDY Pig Biobank2.
There are some mandatory requirements biobank samples must generally comply with to establish the reliability and interpretability of the results of the subsequently performed analyses. The samples must be generated reproducibly, and they must be representative, i.e., adequately reflecting the interested morphological and molecular features of the tissue/organ the samples were taken from7. To be suitable for a wide range of downstream analysis types, the samples must be taken in sufficient quantities and processed according to the demands (including time and temperature conditions) of the different analytical methods, including descriptive histopathological analyses, such as cryohistology, paraffin and plastic histology, immunohistochemistry, in situ hybridization, ultrastructural electron microscopic analyses, and clinical laboratory diagnostic analyses, as well as molecular analyses of DNA, RNA, proteins, and metabolites.
To allow for the assessment of a wide range of distinct quantitative morphological parameters such as numbers, volumes, lengths, or surface areas of distinct tissue structures by quantitative stereological analyses, randomized section planes of the histological samples of the respective organs/tissues need to be prepared7,8,9,10,11. In quantitative morphological studies, the precise determination of the total volume of the tissue, organ, or organ compartment, the samples were taken from (i.e., the reference space) is crucially important7,9,12 to calculate the absolute quantities of the interested parameters within the respective organ, tissue, or organism. Eventually, the effect of embedding-related tissue shrinkage during preparation of histological sections has to be determined and taken into account13. Therefore, quantitative stereological analyses, especially of archived samples (fixed tissue samples, embedded tissue blocks, histological sections, etc.) from previous studies are sometimes severely limited or even impossible12, particularly if volumetry of the respective organs/tissues was not performed, if no adequate sampling designs were applied to warrant representative samples, if the numbers and amounts of available individual samples are insufficient, or if the processing of the samples is incompatible with estimation of the quantitative morphological parameter(s) of interest. Due to the manifold possible influencing factors, the suitability of archive-sample materials for analyses of distinct quantitative morphological parameters cannot unequivocally be answered, but depends on the careful assessment of each individual case.
Thus, as the location, size, number, processing, trimming direction, and orientation of samples will potentially affect the results of the subsequent analyses, these factors are of great importance and must be considered in the experimental design of any study. With regard to these aspects and the special features of the porcine anatomy, comprehensive, detailed, large-scale sampling guidelines adapted to porcine animal models have recently been established, providing a robust reference to standardized, reproducible, and efficient generation of redundant, adequately processed, high-quality samples from more than 50 different porcine organs and tissues6,7.
The methodological descriptions and the video tutorial shown in the present article provide detailed, illustrative, comprehensible, step-by step instructions for practical performance of a variety of techniques for volumetry, sampling of porcine tissues and organs, and processing of tissue samples for different downstream analysis methods. The featured techniques include methods for determination of organ/tissue volumes and densities based on the principles of Archimedes and Cavalieri9, including determination of the dimensions of three-dimensional shrinkage of tissue related to the embedding in different embedding media14 during processing for histological examination, application of practicable volume-weighted systematic random sampling approaches, processing of sampled tissue specimens for different subsequent analyses7,8,9,15, and generation of appropriately oriented and processed samples for potential quantitative stereological analyses7,8,9,10,11. Next to their application in porcine biobank projects, the demonstrated methods are generally appropriate for all studies examining quantitative histo-morphological properties of organs/tissues. Moreover, systematic random sampling designs are particularly beneficial for generation of representative samples in experiments using molecular analysis methods to detect abundance alterations of, e.g., RNAs, proteins, or metabolites in various organs and tissues.
The next paragraphs provide a brief introduction to these methods, while their practical performance is described in the protocol section.
Determination of organ/tissue volumes 
Determination of organ weights and volumes is important in several experimental settings, as these factors might indicate changes, potentially related to experimentally examined factors of interest. The total volume of an organ/tissue is also commonly required to calculate absolute quantitative parameters, (e.g., the total cell number), from stereologically estimated numerical volume densities (i.e., the number of cells per volume unit of tissue)7,12. Apart from techniques using complex technical equipment, such as computer tomography, there are basically three practical methods commonly used to determine the absolute volume of an organ or tissue. The volume of an organ can be determined by &#34;direct volumetric measurement&#34; according to the principle of Archimedes, i.e., measuring the volume of water or saline displaced by the structure when completely submerged. However, for comparably large porcine organs, these approaches are impractical and prone to imprecision, since they require very large volumetric/measuring flasks. More conveniently, the volume of an organ/tissue can be calculated from its weight and density7,12,16, which can efficiently be determined using the &#34;submersion method&#34;7,12,16 (protocol step 1.1.). Organ/tissue volumes can also be estimated using volumetry approaches based on the &#34;principle of Cavalieri&#34; (1598&#8211;1647). In simple terms, the Cavalieri principle states, that if two objects are sectioned in planes parallel to a ground plane, and the profiles of the sections cut through the two objects at corresponding distances from the ground plane have the same areas, the two objects have the same volume. Thus, the volume of arbitrarily shaped objects can be estimated as the product of their section profile areas in parallel, equally distant section planes and the distance between the section planes. This is comprehensible with the following analogy: consider two stacks consisting of the same number of identical coins are placed side by side, one stack with the coins orderly stacked on top of one another yielding a cylindrical shape of the coin stack, and the other stack of coins with off-center positioned coins (Figure 3A). Although the shapes of both coin stacks are different, their volumes are the same, since the areas of the coins at corresponding levels of both stacks (i.e., the areas of profiles of parallel sections cut through both coin stacks in equal distances from the ground) are identical. Estimation of the volumes of porcine organs and tissues using the Cavalieri principle7,12,15 is described in step 1.2.
Determination of the extent of tissue shrinkage related to histological embedding 
In analyses of several quantitative morphological parameters measured in histological tissue sections, the effect of embedding-related tissue shrinkage occurring during tissue processing for histology has to be determined and taken into account. The extent of embedding-related tissue shrinkage may be variable, and depends both on the tissue, its processing, and the embedding medium8,13,17,18,19. Generally, embedding-related changes of the volume of a tissue sample (i.e., mostly shrinkage) occur in all three dimensions of space, and, therefore, affects all dimensional parameters estimated by quantitative stereological analyses8. Basically, the extent of embedding-related tissue shrinkage, expressed as the linear tissue shrinkage factor (fS), can be estimated as shown in step 1.3. and used for correction of (shrinkage-sensitive) quantitative morphological parameters14.
Volume-weighted systematic random sampling of organs/tissues 
For establishment of a biobank collection of porcine organ/tissue samples, volume-weighted systematic random sampling approaches such as described in step 2 have proven to be practical, time-saving, and efficient techniques for generation of representative, multi-purpose tissue samples7,8,9,15.
Generation of Isotropic Uniform Random sections and Vertical Uniform Random sections for quantitative stereological analyses 
Biobank tissue samples need to be suitable for a wide range of different quantitative stereological analysis methods for estimation of a maximum of parameters that could not be determined without an adequately prepared specimen. Nearly all quantitative stereological parameters can be determined, using &#34;isotropic (independent) uniform random (IUR) sections&#34;8,9. In IUR sections, the three-dimensional orientation of the section plane of the tissue sample is randomized. This can be achieved by randomization of the position of the tissue sample relative to the position of the section plane, as applied in the &#34;Isector&#34; method11 (protocol step 3.1), or by randomization of the orientation of the section plane relative to the tissue sample, as in the &#34;Orientator&#34; method10 (protocol step 3.2). In tissue samples, such as skin- or mucosa specimen displaying a naturally present, or defined and properly identifiable vertical axis, preparation of &#34;vertical uniform random (VUR) sections&#34; (protocol step 3.3.) strictly sectioned within the plane of their vertical axis is advantageous8,20. For a complete discourse of the theoretical foundations of IUR/VUR sampling and a comprehensive discussion of potential downstream quantitative stereological analyses, the interested reader is referred to the textbooks of quantitative stereology in life sciences8,9.

<table>
	<tbody>
		<tr>
			<td>Agar</td>
			<td>Carl Roth GmbH, Germany</td>
			<td>Agar (powder), Cat.: 5210.3</td>
			<td>Dissolve approximately 1 g of agar in 10 ml cold water in a glass or plastic beaker, heat in microwave-oven at 700 W, boil the solution twice with rigorous stirring. Cast into mold while still warm and let solidify. Caution: While handling with hot liquid agar, wear protective goggles and gloves.</td>
		</tr>
		<tr>
			<td>Caliper</td>
			<td>Hornbach Baumarkt GmbH, Bornheim, Germany</td>
			<td>Schieblehre Chrom/Vernickelt 120 mm Cat.: 3664902</td>
			<td>Any kind of caliper (mechanical or electronic) will do as well.</td>
		</tr>
		<tr>
			<td>Casting molds (metal)</td>
			<td>Engelbrecht Medizin &#38; Labortechnik, Ederm&#252;nde, Germany</td>
			<td>Einbettsch&#228;lchen aus Edelstahl, 14 x 24 x 5 mm, Cat.: 14302b</td>
			<td>Any other kind of metal casting mold used for paraffin-embedding will do as well.</td>
		</tr>
		<tr>
			<td>Copy templates of cross grids (5mm - 6 cm)</td>
			<td>n.a.</td>
			<td>n.a.</td>
			<td>Copy templates of cross grids (5mm - 6 cm) are provided in the supplemental data file of Albl et al.&#160; Toxicol Pathol. 44, 414-420, doi: 10.1177/0192623316631023 (2016)</td>
		</tr>
		<tr>
			<td>Copy templates of equiangular and cosine-weighted circles</td>
			<td>n.a.</td>
			<td>n.a.</td>
			<td>Copy templates of equiangular and cosine-weighted circles are provided in Nyengaard &#38; Gundersen. Eur Respir Rev. 15, 107-114, doi: 10.1183/09059180.00010101 (2006) and in Gundersen et al. Stereological Principles and Sampling Procedures for Toxicologic Pathologists. In: Haschek and Rousseaux&#180;s Handbook of Toxicologic Pathology. 3rd ed, 215-286, ISBN: 9780124157590 (2013).</td>
		</tr>
		<tr>
			<td>Foldback clamps (YIHAI binder clips, 15 mm and 19 mm)</td>
			<td>Ningbo Tianhong Stationery Co ltd., China</td>
			<td>Y10006 and Y10005</td>
			<td>Any other type of standard office foldback clamps will do as well.</td>
		</tr>
		<tr>
			<td>Forceps (anatomical)</td>
			<td>NeoLab Migge GmbH, Heidelberg, Germany</td>
			<td>neoLab Standard -Pinzette 130 mm, anatomisch, rund, Cat.: 1-1811</td>
			<td>Any type of anatomical forceps will do.</td>
		</tr>
		<tr>
			<td>Formaldehyde-solution 4%</td>
			<td>SAV-Liquid Produktion GmbH, Flintsbach, Germany</td>
			<td>Formaldehyd 37/40 %, Cat.: 1000411525005</td>
			<td>Dilute to 4% from concentrated solution. Buffer to neutral pH. Wear appropriate eye-, hand- and respiratory protection. Process tissue samples fixed in formaldehyde solution under an exhaust hood and wear protective goggles and laboratory gloves.</td>
		</tr>
		<tr>
			<td>Graph paper (for calibration)</td>
			<td>B&#252;romarkt B&#246;ttcher AG, Jena, Germany. www.bueromarkt-ag.de</td>
			<td>Penig Millimeterpapier A4, Cat.: 2514</td>
			<td>Any type of graph paper (scaled in millimeter) will do.</td>
		</tr>
		<tr>
			<td>Laboratory beakers (5ml, 10 ml, 50 ml, 100 ml)</td>
			<td>NeoLab Migge GmbH, Heidelberg, Germany</td>
			<td>Becherglas SIMAX&#174; , niedrige Form, Borosilikatglas 3.3 Cat.: E-1031, E-1032, E-1035, E-1036</td>
			<td>Any kind of glass- or plastic beakers of 5 &#8211; 100 ml volume will do.</td>
		</tr>
		<tr>
			<td>Laboratory scale(s)</td>
			<td>Mettler Toledo GmbH, Gie&#223;en, Germany</td>
			<td>PM6000</td>
			<td rowspan="2">Any standard laboratory scales with measuring ranges between 0.1 mg to approximately 20 g, respectively between 100 mg to approximately 500 g will do</td>
		</tr>
		<tr>
			<td></td>
			<td>Sartorius AG, G&#246;ttingen, Germany</td>
			<td>BP61S</td>
		</tr>
		<tr>
			<td>Microtome blades</td>
			<td>Engelbrecht Medizin &#38; Labortechnik, Ederm&#252;nde, Germany</td>
			<td>FEATHER Microtome blasdes S35, Cat.:14700</td>
			<td>Any kind of single-use microtome blades will do.</td>
		</tr>
		<tr>
			<td rowspan="2">Morphometry/planimetry software/system</td>
			<td>National Institute of Health (NIH)</td>
			<td>ImageJ</td>
			<td>Download from https://www. imagej.nih.gov/ij/ (1997).</td>
		</tr>
		<tr>
			<td>Zeiss-Kontron, Eching, Germany</td>
			<td>VideoplanTM image analysis system</td>
			<td>Out of stock</td>
		</tr>
		<tr>
			<td>Photo camera</td>
			<td>Nikon</td>
			<td>D40</td>
			<td>Any kind of digital photocamera that can be mounted to a tripod&#160; will do.</td>
		</tr>
		<tr>
			<td>Plastic transparencies</td>
			<td>Avery Zweckform GmbH, Oberlaindern, Germany</td>
			<td>Laser Overhead-Folie DINA4 Cat.:&#160; 3562</td>
			<td>Any (laser)-printable plastic transparency will do.</td>
		</tr>
		<tr>
			<td>Random number tables</td>
			<td>n.a.</td>
			<td>n.a.</td>
			<td>Random number tables can conveniently be generated (with defined numbers of random numbers and within defined intervals), using random number generators, such as: https://www.random.org/</td>
		</tr>
		<tr>
			<td>Razor blades</td>
			<td>Plano GmbH, Wetzlar, Germany</td>
			<td>T5016</td>
			<td>Any kind of razor blades will do.</td>
		</tr>
		<tr>
			<td>Ruler</td>
			<td>B&#252;romarkt B&#246;ttcher AG, Jena, Germany. www.bueromarkt-ag.de</td>
			<td>Office-Point Lineal 30 cm, Kunststoff, transparent, Cat.: ln30</td>
			<td>Any kind of cm-mm-scaled ruler will do as well.</td>
		</tr>
		<tr>
			<td>Saline (0.9%)</td>
			<td>Carl Roth GmbH, Germany</td>
			<td>Natriumchlorid, &#62;99% Cat.: 0601.1</td>
			<td>To prepare 0.9% saline, dissolve 9 g NaCl in 1000 ml of distilled water at 20&#176;C.</td>
		</tr>
		<tr>
			<td>Scalpel blades</td>
			<td>Aesculap AG &#38; Co KG, Tuttlingen, Germany</td>
			<td>BRAUN Surgical blades N&#176;22</td>
			<td>Any kind of scalpel blades will do.</td>
		</tr>
		<tr>
			<td>Scanner</td>
			<td>Hewlett-Packard</td>
			<td>hp scanjet 7400c</td>
			<td>Any type of standard office scanner capable of scanning with resolutions from 150-600 dpi will do.</td>
		</tr>
		<tr>
			<td>Slicing devices</td>
			<td>n.a.</td>
			<td>n.a.</td>
			<td>Examples forself constructed slicing devices can be found in Knust, et al. Anatomical record. 292, 113-122, doi: 10.1002/ar.20747 (2009) and in the supplemental data file of Albl et al.&#160; Toxicol Pathol. 44, 414-420, doi: 10.1177/0192623316631023 (2016).</td>
		</tr>
		<tr>
			<td>Spherical casting molds (e.g., in 25.5 mm diameter)</td>
			<td>Pralinen-Zutaten.de, Windach, Germany</td>
			<td>Pralinen-Hohlkugeln Vollmilch, 25.5 mm</td>
			<td>Spherical casting molds can as well be be self-constructed, or obtained from other confectioner suppliers (for for pralines). The casting molds indicated here are actually the package/wrapping of hollow pralines bodies (first eat the pralines and then use the package for generation of i-sector sections)</td>
		</tr>
		<tr>
			<td>Thin wire</td>
			<td>Basteln &#38; Hobby Schobes, Stra&#223;furth, Germany. www,bastel-welt.de</td>
			<td>Messingdraht (0.3 mm) Cat.: 216464742</td>
			<td>Any other kind of thin wire will also do.</td>
		</tr>
		<tr>
			<td>Tissue paper</td>
			<td>NeoLab Migge GmbH, Heidelberg, Germany</td>
			<td>Declcate Task Wipes-White, Cat.: 1-5305</td>
			<td>Any other kind of laboratory tissue paper will do as well.</td>
		</tr>
		<tr>
			<td>Waterproof pen</td>
			<td>Staedler Mars GmbH &#38; Co KG, N&#252;rnberg, Grmany</td>
			<td>Lumocolor permanent 313, 0.4 mm, S, black, Cat.: 313-2</td>
			<td>Any other kind of waterproof pen will do as well.</td>
		</tr>
	</tbody>
</table>

sampling strategies and processing of biobank tissue samples from porcine biomedical models

In translational medical research, porcine models have steadily become more popular. Considering the high value of individual animals, particularly of genetically modified pig models, and the often-limited number of available animals of these models, establishment of (biobank) collections of adequately processed tissue samples suited for a broad spectrum of subsequent analyses methods, including analyses not specified at the time point of sampling, represent meaningful approaches to take full advantage of the translational value of the model. With respect to the peculiarities of porcine anatomy, comprehensive guidelines have recently been established for standardized generation of representative, high-quality samples from different porcine organs and tissues. These guidelines are essential prerequisites for the reproducibility of results and their comparability between different studies and investigators. The recording of basic data, such as organ weights and volumes, the determination of the sampling locations and of the numbers of tissue samples to be generated, as well as their orientation, size, processing and trimming directions, are relevant factors determining the generalizability and usability of the specimen for molecular, qualitative, and quantitative morphological analyses. Here, an illustrative, practical, step-by-step demonstration of the most important techniques for generation of representative, multi-purpose biobank specimen from porcine tissues is presented. The methods described here include determination of organ/tissue volumes and densities, the application of a volume-weighted systematic random sampling procedure for parenchymal organs by point-counting, determination of the extent of tissue shrinkage related to histological embedding of samples, and generation of randomly oriented samples for quantitative stereological analyses, such as isotropic uniform random (IUR) sections generated by the &#34;Orientator&#34; and &#34;Isector&#34; methods, and vertical uniform random (VUR) sections.

Submersion technique for determination of tissue/organ density
Figure 12A-B shows the representative determination of the density and volume of a porcine kidney using the submersion technique described in step 1.1 (Figure 1, Figure 2). More representative results of density measurements of additional porcine organs and tissues...

Watch this Scientific Journal Video about Sampling Strategies and Processing of Biobank Tissue Samples from Porcine Biomedical Models at JoVE.com

Sampling Strategies and Processing of Biobank Tissue Samples from Porcine Biomedical Models

The practical application and performance of methods for generation of representative tissue samples of porcine animal models for a broad spectrum of downstream analyses in biobank projects are demonstrated, including volumetry, systematic random sampling, and differential processing of tissue samples for qualitative and quantitative morphologic and molecular analyses types.

In translational medical research, porcine models have steadily become more popular. Considering the high value of individual animals, particularly of ...

sampling-strategies-processing-biobank-tissue-samples-from-porcine

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15.5K Views.  LMU Munich. The practical application and performance of methods for generation of representative tissue samples of porcine animal models for a broad spectrum of downstream analyses in biobank projects are demonstrated, including volumetry, systematic random sampling, and differential processing of tissue samples for qualitative and quantitative morphologic and molecular analyses types.

Video: Sampling Strategies and Processing of Biobank Tissue Samples from Porcine Biomedical Models

Generation of Alginate Microspheres for Biomedical Applications

Alginate-based materials have received considerable attention for biomedical applications because of their hydrophilic nature, biocompatibility, and physical architecture. Applications include cell encapsulation, drug delivery, stem cell culture, and tissue engineering scaffolds. In fact, clinical trials are currently being performed in which islets are encapsulated in PLO coated alginate microbeads as a treatment of type I diabetes. However, large numbers of islets are required for efficacy due to poor survival following transplantation. The ability to locally stimulate microvascular network formation around the encapsulated cells may increase their viability through improved transport of oxygen, glucose and other vital nutrients. Fibroblast growth factor-1 (FGF-1) is a naturally occurring growth factor that is able to stimulate blood vessel formation and improve oxygen levels in ischemic tissues. The efficacy of FGF-1 is enhanced when it is delivered in a sustained fashion rather than a single large-bolus administration. The local long-term release of growth factors from islet encapsulation systems could stimulate the growth of blood vessels directly towards the transplanted cells, potentially improving functional graft outcomes. In this article, we outline procedures for the preparation of alginate microspheres for use in biomedical applications. In addition, we describe a method we developed for generating multilayered alginate microbeads. Cells can be encapsulated in the inner alginate core, and angiogenic proteins in the outer alginate layer. The release of proteins from this outer layer would stimulate the formation of local microvascular networks directly towards the transplanted islets.

In the following sections, we outline procedures for the preparation of alginate microspheres for use in biomedical applications. We specifically illustrate a technique for creating multilayered alginate microspheres for the dual purpose of cell and protein encapsulation as a potential treatment for type 1 diabetes.

Alginate-based materials have received considerable attention for biomedical applications because of their hydrophilic nature, biocompatibility, and ...

How to Measure Cortical Folding from MR Images: a Step-by-Step Tutorial to Compute Local Gyrification Index

Cortical folding (gyrification) is determined during the first months of life, so that adverse events occurring during this period leave traces that will be identifiable at any age. As recently reviewed by Mangin and colleagues2, several methods exist to quantify different characteristics of gyrification. For instance, sulcal morphometry can be used to measure shape descriptors such as the depth, length or indices of inter-hemispheric asymmetry3. These geometrical properties have the advantage of being easy to interpret. However, sulcal morphometry tightly relies on the accurate identification of a given set of sulci and hence provides a fragmented description of gyrification. A more fine-grained quantification of gyrification can be achieved with curvature-based measurements, where smoothed absolute mean curvature is typically computed at thousands of points over the cortical surface4. The curvature is however not straightforward to comprehend, as it remains unclear if there is any direct relationship between the curvedness and a biologically meaningful correlate such as cortical volume or surface. To address the diverse issues raised by the measurement of cortical folding, we previously developed an algorithm to quantify local gyrification with an exquisite spatial resolution and of simple interpretation. Our method is inspired of the Gyrification Index5, a method originally used in comparative neuroanatomy to evaluate the cortical folding differences across species. In our implementation, which we name local Gyrification Index (lGI1), we measure the amount of cortex buried within the sulcal folds as compared with the amount of visible cortex in circular regions of interest. Given that the cortex grows primarily through radial expansion6, our method was specifically designed to identify early defects of cortical development.
In this article, we detail the computation of local Gyrification Index, which is now freely distributed as a part of the FreeSurfer Software (<a href="http://surfer.nmr.mgh.harvard.edu/">http://surfer.nmr.mgh.harvard.edu/</a>, Martinos Center for Biomedical Imaging, Massachusetts General Hospital). FreeSurfer provides a set of automated reconstruction tools of the brain's cortical surface from structural MRI data. The cortical surface extracted in the native space of the images with sub-millimeter accuracy is then further used for the creation of an outer surface, which will serve as a basis for the lGI calculation. A circular region of interest is then delineated on the outer surface, and its corresponding region of interest on the cortical surface is identified using a matching algorithm as described in our validation study1. This process is repeatedly iterated with largely overlapping regions of interest, resulting in cortical maps of gyrification for subsequent statistical comparisons (Fig. 1). Of note, another measurement of local gyrification with a similar inspiration was proposed by Toro and colleagues7, where the folding index at each point is computed as the ratio of the cortical area contained in a sphere divided by the area of a disc with the same radius. The two implementations differ in that the one by Toro et al. is based on Euclidian distances and thus considers discontinuous patches of cortical area, whereas ours uses a strict geodesic algorithm and include only the continuous patch of cortical area opening at the brain surface in a circular region of interest.

Measuring gyrification (cortical folding) at any age represents a window into early brain development. Hence, we previously developed an algorithm to measure local gyrification at thousands of points over the hemisphere1. In this paper, we detail the computation of this local gyrification index.

Cortical folding (gyrification) is determined during the first months of life, so that adverse events occurring during this period leave traces that will ...

Processing of Primary Brain Tumor Tissue for Stem Cell Assays and Flow Sorting

Brain tumors are typically comprised of morphologically diverse cells that express a variety of neural lineage markers. Only a relatively small fraction of cells in the tumor with stem cell properties, termed brain tumor initiating cells (BTICs), possess an ability to differentiate along multiple lineages, self-renew, and initiate tumors in vivo. We applied culture conditions originally used for normal neural stem cells (NSCs) to a variety of human brain tumors and found that this culture method specifically selects for stem-like populations. Serum-free medium (NSC) allows for the maintenance of an undifferentiated stem cell state, and the addition of bFGF and EGF allows for the proliferation of multi-potent, self-renewing, and expandable tumorspheres.
To further characterize each tumor's BTIC population, we evaluate cell surface markers by flow cytometry. We may also sort populations of interest for more specific characterization. Self-renewal assays are performed on single BTICs sorted into 96 well plates; the formation of tumorspheres following incubation at 37 &deg;C indicates the presence of a stem or progenitor cell. Multiple cell numbers of a particular population can also be sorted in different wells for limiting dilution analysis, to analyze self-renewal capacity. We can also study differential gene expression within a particular cell population by using single cell RT-PCR.
The following protocols describe our procedures for the dissociation and culturing of primary human samples to enrich for BTIC populations, as well as the dissociation of tumorspheres. Also included are protocols for staining for flow cytometry analysis or sorting, self-renewal assays, and single cell RT-PCR.

The identification of brain tumor initiating cells (BTICs), the rare cells within a heterogeneous tumor possessing stem cell properties, provides new insights into human brain tumor pathogenesis. We have refined specific culture conditions to enrich for BTICs, and we routinely use flow cytometry to further enrich these populations. Self-renewal assays and transcript analysis by single cell RT-PCR can subsequently be performed on these isolated cells.

Brain tumors are typically comprised of morphologically diverse cells that express a variety of neural lineage markers. Only a relatively small fraction ...

The Bovine Lung in Biomedical Research: Visually Guided Bronchoscopy, Intrabronchial Inoculation and In Vivo Sampling Techniques

There is an ongoing search for alternative animal models in research of respiratory medicine. Depending on the goal of the research, large animals as models of pulmonary disease often resemble the situation of the human lung much better than mice do. Working with large animals also offers the opportunity to sample the same animal repeatedly over a certain course of time, which allows long-term studies without sacrificing the animals.
The aim was to establish in vivo sampling methods for the use in a bovine model of a respiratory Chlamydia psittaci infection. Sampling should be performed at various time points in each animal during the study, and the samples should be suitable to study the host response, as well as the pathogen under experimental conditions.
Bronchoscopy is a valuable diagnostic tool in human and veterinary medicine. It is a safe and minimally invasive procedure. This article describes the intrabronchial inoculation of calves as well as sampling methods for the lower respiratory tract. Videoendoscopic, intrabronchial inoculation leads to very consistent clinical and pathological findings in all inoculated animals and is, therefore, well-suited for use in models of infectious lung disease. The sampling methods described are bronchoalveolar lavage, bronchial brushing and transbronchial lung biopsy. All of these are valuable diagnostic tools in human medicine and could be adapted for experimental purposes to calves aged 6-8 weeks. The samples obtained were suitable for both pathogen detection and characterization of the severity of lung inflammation in the host.

The Bovine Lung in Biomedical Research: Visually Guided Bronchoscopy, Intrabronchial Inoculation and In Vivo Sampling Techniques

This article describes bronchoscopic techniques in the bovine lung under experimental conditions, i.e. bronchoscopically guided inoculation, bronchoalveolar lavage, bronchial brushing, and transbronchial lung biopsy.

There is an ongoing search for alternative animal models in research of respiratory medicine. Depending on the goal of the research, large animals as ...

Unbiased Deep Sequencing of RNA Viruses from Clinical Samples

Here we outline a next-generation RNA sequencing protocol that enables de novo assemblies and intra-host variant calls of viral genomes collected from clinical and biological sources. The method is unbiased and universal; it uses random primers for cDNA synthesis and requires no prior knowledge of the viral sequence content. Before library construction, selective RNase H-based digestion is used to deplete unwanted RNA &#8212; including poly(rA) carrier and ribosomal RNA &#8212; from the viral RNA sample. Selective depletion improves both the data quality and the number of unique reads in viral RNA sequencing libraries. Moreover, a transposase-based &#39;tagmentation&#39; step is used in the protocol as it reduces overall library construction time. The protocol has enabled rapid deep sequencing of over 600 Lassa and Ebola virus samples-including collections from both blood and tissue isolates-and is broadly applicable to other microbial genomics studies.

This protocol describes a rapid and broadly applicable method for unbiased RNA-sequencing of viral samples from human clinical isolates.

Here we outline a next-generation RNA sequencing protocol that enables de novo assemblies and intra-host variant calls of viral genomes collected from ...

Absorption of Nasal and Bronchial Fluids: Precision Sampling of the Human Respiratory Mucosa and Laboratory Processing of Samples

The methods of nasal absorption (NA) and bronchial absorption (BA) use synthetic absorptive matrices (SAM) to absorb the mucosal lining fluid (MLF) of the human respiratory tract. NA is a non-invasive technique which absorbs fluid from the inferior turbinate, and causes minimal discomfort. NA has yielded reproducible results with the ability to frequently repeat sampling of the upper airway. 
By comparison, alternative methods of sampling the respiratory mucosa, such as nasopharyngeal aspiration (NPA) and conventional swabbing, are more invasive and may result in greater data variability. Other methods have limitations, for instance, biopsies and bronchial procedures are invasive, sputum contains many dead and dying cells and requires liquefaction, exhaled breath condensate (EBC) contains water and saliva, and lavage samples are dilute and variable.
BA can be performed through the working channel of a bronchoscope in clinic. Sampling is well tolerated and can be conducted at multiple sites in the airway. BA results in MLF samples being less dilute than bronchoalveolar lavage (BAL) samples.
This article demonstrates the techniques of NA and BA, as well as the laboratory processing of the resulting samples, which can be tailored to the desired downstream biomarker being measured. These absorption techniques are useful alternatives to the conventional sampling techniques used in clinical respiratory research.

This manuscript describes the use of nasal and bronchial absorption techniques, specifically using synthetic absorptive matrices (SAM) to sample the mucosal lining fluid (MLF) of the upper and lower airway. These methods provide better standardization and tolerability than existing respiratory sampling techniques.

The methods of nasal absorption (NA) and bronchial absorption (BA) use synthetic absorptive matrices (SAM) to absorb the mucosal lining fluid (MLF) of the ...

Improvement of a Closed Chest Porcine Myocardial Infarction Model by Standardization of Tissue and Blood Sampling Procedures

Myocardial ischemia reperfusion (I/R) injury contributes to almost half of the necrotic area after myocardial infarction. To date there is no approved drug to prevent or reduce myocardial I/R injury. The study and understanding of the pathophysiological mechanisms of myocardial I/R injury is essential to develop successful treatments. Large animal experiments are an important step in translational methods. The porcine model of acute myocardial infarction has been established and described by ourselves and others. We aimed to further improve the value of the model by focusing in detail on the sampling techniques for use in future experiments. Furthermore, we emphasize small but important steps that can affect the quality of the final results. To mimic the clinical situation of myocardial I/R injury, a percutaneous coronary intervention (PCI) catheter was inserted into the left anterior descending coronary artery (LAD) of an anesthetized pig. &#176;&#176;&#176;This model mimics acute myocardial infarction and PCI treatment in humans with the possibility of accurately determining the area at risk as well as the necrotic- and viable ischemic tissue. Here the model was used to investigate the effect of a bicyclic peptide inhibitor of FXIIa. The model can also be modified to allow longer reperfusion times to study later effects of myocardial infarction.

Here we demonstrate a protocol to standardize sampling procedures of an established porcine model of acute myocardial infarction in order to increase its translational value in the understanding of the pathophysiology of myocardial ischemia/reperfusion injury and to test novel drug candidates.

Myocardial ischemia reperfusion (I/R) injury contributes to almost half of the necrotic area after myocardial infarction. To date there is no approved ...

Human Subcutaneous Adipose Tissue Sampling Using a Mini-Liposuction Technique

Studies on adipose tissue are useful in understanding metabolic and other conditions. Human subcutaneous adipose tissue is accessible. With appropriate training and strict adherence to aseptic technique, subcutaneous adipose samples can be safely and efficiently obtained in a non-clinical setting by researchers. Following the administration of local anesthetic lateral to the umbilicus, a 14 G needle attached to a 5 or 10 mL syringe is inserted through the skin into the subcutaneous tissue. Under suction, the syringe is moved in a reciprocating, slicing motion to isolate fragments of adipose tissue. Withdrawing the plunger is enough to ensure that adipose tissue fragments are aspirated through the needle into the syringe. A single biopsy can collect about 200 mg of tissue. This biopsy technique is very safe for both participants and research staff. Following the biopsy, participants can resume most everyday activities, although they should avoid swimming and overly strenuous activities for 48 h to avoid excessive bleeding. Participants can safely undergo 2 biopsies within a single day, meaning that the technique can be applied in before-after acute intervention studies.

The manuscript and associated video demonstrate a percutaneous biopsy technique to obtain samples of subcutaneous adipose tissue from areas surrounding the umbilicus. This method is a low-risk and efficient way to investigate a range of parameters (e.g., gene or protein expression, enzyme activity, lipid content) within adipose tissue.

Studies on adipose tissue are useful in understanding metabolic and other conditions. Human subcutaneous adipose tissue is accessible. With appropriate ...

Repetitive Blood Sampling from the Subclavian Vein of Conscious Rat

Rats are widely used in pharmacokinetics (PK) and toxicokinetic (TK) studies that need to collect a certain amount of blood at specific time points to detect drug exposure. The rat blood sampling method determines the quality of the plasma and further affects the precision of the test results. The subclavian vein blood collection method described in this protocol collects blood samples repeatedly in the conscious state of animals to meet the needs of PK and TK tests. The skills of restraint handling and appropriate procedure of needle incision ensure the success rate of blood collection. It is easy to operate while ensuring the quality of plasma and at the same time catering to animal welfare. However, this method requires skilled operation, and an improper one may cause animal weakness, pain, lameness, and even mortality. The current method has been used in the testing facility for a 4-week oral toxicity study in Sprague Dawley (SD) rats with TK. The maximum amount of blood collected within 24 h did not exceed 20% of the animal's total blood. The animals' body weight was more than 200 g for males and females. The data showed that the animals' bodyweight increased steadily every week, and the clinical observation was normal after repetitive sample collection.

The present protocol describes a simple and efficient method for collecting blood from the subclavian vein in rats. It enables rapid, timely, and easily identifiable sampling without anesthesia and obtains high-quality blood through repetitive sample collection.

Rats are widely used in pharmacokinetics (PK) and toxicokinetic (TK) studies that need to collect a certain amount of blood at specific time points to ...

Dissection Techniques and Histological Sampling of the Heart in Large Animal Models for Cardiovascular Diseases

The standard gross examination and sampling are key elements in the reproducibility and success of experimental studies of cardiovascular diseases carried out in large animals. Considering the complex anatomy of the heart, interspecies differences, and the types of compensatory and pathological reactions, consistent protocols are challenging to implement. The utilization of multiple dissection protocols is usually adapted to suit the prosector's experience, and personal preference continues to be a source of experimental and interobserver variability. Here, the aim is to present the main anatomical features and landmarks, dissection protocols, and histological sampling standards of the heart in some commonly used species (including dogs, pigs, ruminants, and cats) as models of cardiovascular diseases.
Two standard gross examination protocols are presented here. First, the inflow-outflow method, which follows the physiological blood flow direction through the heart and large vessels (frequently used in dogs, ruminants, and pigs), and second, the four-chamber dissection technique (exemplified in cats). Both techniques can be adapted to any species in certain experimental circumstances. The sampling protocols include all the areas of interest (sinoatrial node, ventricles, interventricular septum, atria, valves, and aorta), and if properly carried out, improve both the reproducibility and reliability of experimental studies.

Due to the complex anatomy, a consistently reproducible dissection and harvesting protocol for cardiac samples can be challenging to implement. This manuscript presents the key elements of some standard cardiac dissection protocols, highlighting both the gross examination approaches and the sampling sites commonly used for histopathologic examination.

The standard gross examination and sampling are key elements in the reproducibility and success of experimental studies of cardiovascular diseases carried ...