Name: synthetic antigen controls for immunohistochemistry
Uploaded: 2021-08-23T15:00:00
Description: Watch this Scientific Journal Video about Synthetic Antigen Controls for Immunohistochemistry at JoVE.com

The authors gratefully acknowledge their colleagues Jeffrey Tom and Aimin Song for peptide synthesis, Nianfeng Ge for TMA construction, Shari Lau for IHC staining, Melissa Edick for digital microscopic scanning, and Hai Ngu for digital image quantification.

1. Preparation of stock solution and tools
<ol>
	<li>Prepare 20 mL of a 25% w/v BSA solution by mixing 5 g BSA powder in 14 mL of PBS, pH 7.2 in a 50 mL conical tube until evenly dispersed. Vortex as necessary to disperse the BSA powder.
	<ol>
		<li>Keep the solution overnight at 4 &#176;C to allow complete dissolution. Adjust the final volume to 20 mL with PBS to make a 25% w/v stock solution.</li>
	</ol>
	</li>
	<li>Prepare 20 mL of a 31.3% w/v BSA solution by mixing 6.26 g BSA powder in 13 mL of PBS, pH 7.2 in a 50 ...

<ol>
	<li>Torlakovic, E. E., 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=Standardization+of+positive+controls+in+diagnostic+immunohistochemistry:+recommendations+from+the+International+Ad+Hoc+Expert+Committee.">Standardization of positive controls in diagnostic immunohistochemistry: recommendations from the International Ad Hoc Expert Committee.</a> Applied Immunohistochemistry and Molecular Morphology. 23 (1), 1-18 (2015).</li><li>H&#246;tzel, K. J., 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=Synthetic+antigen+gels+as+practical+controls+for+standardized+and+quantitative+immunohistochemistry.">Synthetic antigen gels as practical controls for standardized and quantitative immunohistochemistry.</a> Journal of Histochemistry and Cytochemistry. 67 (5), 309-334 (2019).</li><li>Hewitt, S. M., Baskin, D. G., Frevert, C. W., Stahl, W. L., Rosa-Molinar, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controls+for+immunohistochemistry:+The+histochemical+society's+standards+of+practice+for+validation+of+immunohistochemical+assays.">Controls for immunohistochemistry: The histochemical society's standards of practice for validation of immunohistochemical assays.</a> Journal of Histochemistry and Cytochemistry. 62 (10), 693-697 (2014).</li><li>Torlakovic, E. E., 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=Standardization+of+negative+controls+in+diagnostic+immunohistochemistry:+recommendations+from+the+international+ad+hoc+expert+panel.">Standardization of negative controls in diagnostic immunohistochemistry: recommendations from the international ad hoc expert panel.</a> Applied Immunohistochemistry and Molecular Morphology. 22 (4), 241-252 (2014).</li><li>Martinez-Morilla, 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=Quantitative+assessment+of+PD-L1+as+an+analyte+in+immunohistochemistry+diagnostic+assays+using+a+standardized+cell+line+tissue+microarray.">Quantitative assessment of PD-L1 as an analyte in immunohistochemistry diagnostic assays using a standardized cell line tissue microarray.</a> Laboratory Investigation. 100, 4-15 (2020).</li><li>Ben-David, U., 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=Genetic+and+transcriptional+evolution+alters+cancer+cell+line+drug+response.">Genetic and transcriptional evolution alters cancer cell line drug response.</a> Nature. 560 (7718), 325-330 (2018).</li><li>Sompuram, S. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardizing+immunohistochemistry:+A+new+reference+control+for+detecting+staining+problems.">Standardizing immunohistochemistry: A new reference control for detecting staining problems.</a> Journal of Histochemistry and Cytochemistry. 63 (9), 681-690 (2015).</li><li>Vani, K., 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=Levey-Jennings+analysis+uncovers+unsuspected+causes+of+immunohistochemistry+stain+variability.">Levey-Jennings analysis uncovers unsuspected causes of immunohistochemistry stain variability.</a> Applied Immunohistochemistry and Molecular Morphology. 24 (10), 688-694 (2016).</li><li>Brandtzaeg, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+immunofluorescence+with+artificial+sections+of+selected+antigenicity.">Evaluation of immunofluorescence with artificial sections of selected antigenicity.</a> Immunology. 22, 177-183 (1972).</li><li>Matute, C., Streit, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monoclonal+antibodies+demonstrating+GABA-Iike+immunoreactivity.">Monoclonal antibodies demonstrating GABA-Iike immunoreactivity.</a> Histochemistry. 86, 147-157 (1986).</li><li>Ottersen, O. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postembedding+light-+and+electron+microscopic+immunocytochemistry+of+amino+acids:+description+of+a+new+model+system+allowing+identical+conditions+for+specificity+testing+and+tissue+processing.">Postembedding light- and electron microscopic immunocytochemistry of amino acids: description of a new model system allowing identical conditions for specificity testing and tissue processing.</a> Experimental Brain Research. 69, 167-174 (1987).</li><li>Fowler, C. B., Cunningham, R. E., O'Leary, T. J., Mason, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term='Tissue+surrogates'+as+a+model+for+archival+formalin-fixed+paraffin-embedded+tissues.">'Tissue surrogates' as a model for archival formalin-fixed paraffin-embedded tissues.</a> Laboratory Investigation. 87, 836-846 (2007).</li><li>Arabi, S. H., 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=Serum+albumin+hydrogels+in+broad+pH+and+temperature+ranges:+characterization+of+their+self-assembled+structures+and+nanoscopic+and+macroscopic+properties.">Serum albumin hydrogels in broad pH and temperature ranges: characterization of their self-assembled structures and nanoscopic and macroscopic properties.</a> Biomaterials Science. 6 (3), 478-492 (2018).</li><li>Schrohl, A. -. S., Pedersen, H. C., Jensen, S. S., Nielsen, S. L., Br&#252;nner, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+epidermal+growth+factor+receptor+2+(HER2)+immunoreactivity:+specificity+of+three+pharmacodiagnostic+antibodies.">Human epidermal growth factor receptor 2 (HER2) immunoreactivity: specificity of three pharmacodiagnostic antibodies.</a> Histopathology. 59, 975-983 (2011).</li><li>Lear, S., Cobb, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pep-Calc.com:+a+set+of+web+utilities+for+the+calculation+of+peptide+and+peptoid+properties+and+automatic+mass+spectral+peak+assignment.">Pep-Calc.com: a set of web utilities for the calculation of peptide and peptoid properties and automatic mass spectral peak assignment.</a> Journal of Computer-Aided Molecular Design. 30, 271-277 (2016).</li><li>Camp, R. L., Chung, G. G., Rimm, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+subcellular+localization+and+quantification+of+protein+expression+in+tissue+microarrays.">Automated subcellular localization and quantification of protein expression in tissue microarrays.</a> Nature Medicine. 8 (11), 1323-1327 (2002).</li><li>Angelo, M., 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=Multiplexed+ion+beam+imaging+of+human+breast+tumors.">Multiplexed ion beam imaging of human breast tumors.</a> Nature Medicine. 20 (4), 436-442 (2014).</li><li>Buus, 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=High-resolution+mapping+of+linear+antibody+epitopes+using+ultrahigh-density+peptide+microarrays.">High-resolution mapping of linear antibody epitopes using ultrahigh-density peptide microarrays.</a> Molecular and Cellular Proteomics. 11 (12), 1790-1800 (2012).</li><li>Forsstr&#246;m, 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=Proteome-wide+epitope+mapping+of+antibodies+using+ultra-dense+peptide+arrays.">Proteome-wide epitope mapping of antibodies using ultra-dense peptide arrays.</a> Molecular and Cellular Proteomics. 13 (6), 1585-1597 (2014).</li><li>Forsstr&#246;m, 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=Dissecting+antibodies+with+regards+to+linear+and+conformational+epitopes.">Dissecting antibodies with regards to linear and conformational epitopes.</a> PLoS One. 10 (3), 0121673 (2015).</li><li>Prasad, 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=Toward+a+consensus+on+applying+quantitative+liquid+chromatography-tandem+mass+spectrometry+proteomics+in+translational+pharmacology+research:+A+white+paper.">Toward a consensus on applying quantitative liquid chromatography-tandem mass spectrometry proteomics in translational pharmacology research: A white paper.</a> Clinical Pharmacology and Therapeutics. 106 (3), 525-543 (2019).</li></ol>

This method allows the user to create uniform samples of known composition and antigen concentration as standards in IHC reactions, using materials and techniques familiar to most histology laboratories. The most crucial step is to identify the epitope to which the antibody of interest binds. This protocol describes using a linear peptide antigen from the ERBB2/HER2 ICD. The same protocol can be used to form BSA gels containing oligonucleotides, fluorescent labels, protein domains, or full-length proteins. This latter ap...

Immunohistochemistry (IHC) allows the sensitive and specific, spatially precise detection of target antigens in formalin-fixed, paraffin-embedded (FFPE) tissue sections. However, IHC staining results may be affected by multiple variables, including warm and cold ischemia time, tissue fixation, tissue pretreatment, antibody reactivity and concentration, assay detection chemistry, and reaction times1. Accordingly, reproducible performance and interpretation of IHC reactions require rigorous control of these variables and the use of well-characterized positive and negative control samples. Frequently used controls include paraffin-embedded tissues or cultured cell lines known from independent analyses to express the antigen of interest, but such samples are not always available1. Furthermore, the expression levels of the target antigens in tissues and cell line controls are generally understood only qualitatively and may be variable. Controls containing reproducible, precisely known concentrations of target antigen can assist in the optimization of IHC reaction conditions. A general method, adaptable to a variety of antigen types in a physiologically relevant range of concentrations to create synthetic IHC control samples, has been described by the authors2. A detailed protocol is provided here for the creation and use of this type of standard.
Appropriate controls are essential for the valid interpretation of IHC assays1,3,4. Tissues, cultured cells, and peptide-coated substrates have been employed as IHC controls according to the investigators&#39; specific needs. The advantages and limitations inherent in using tissues as IHC controls have been extensively discussed1,4. For many antibodies, appropriate controls can be chosen from selected normal tissues containing cell populations expressing the target antigen over a wide dynamic range. Tissue controls are less suitable when the target antigen is not well-characterized concerning expression site or abundance, or when potentially cross-reacting antigens are co-expressed in the same cells or tissue sites. In these contexts, blocks of cultured cell lines expressing the antigen of interest can be helpful. For providing further evidence of target specificity, cell lines can be engineered to over-or under-express target antigens. For example, such an approach was recently used to evaluate a variety of anti-PD-L1 assays using a tissue microarray of isogenic cell lines expressing a range of PD-L1 antigen5. Practical limitations to the routine use of cell line blocks include the cost and time needed to produce sufficient cell numbers and the fact that the expression of some antigens may not be reliably consistent, even within clonal cell lines6. Synthetic peptides are a third option for IHC controls for antibodies that recognize short linear epitopes. Steven Bogen and colleagues have published extensively on the use of peptides coupled to the surface of glass slides7,8 and glass beads9. One study by this group demonstrated that quantitative analysis of peptide-based IHC controls could detect staining process variation missed by qualitative evaluation of tissue controls analyzed in parallel10. While standards using bead-based antigens could be widely applicable, many details are proprietary to the authors, limiting widespread adoption.
Another approach to IHC standards incorporates target antigens into artificially created protein gels. This concept was first demonstrated by Per Brandtzaeg in 1972 in a study in which normal rabbit serum was polymerized using glutaraldehyde11. Small blocks of the resulting gel were then soaked for 1-4 weeks in solutions containing the immunoglobulin antigens of interest at various concentrations. After alcohol fixation and paraffin embedding, sections of the resulting controls were shown to stain with intensities corresponding to the logarithm of the antigen solutions in which they had been soaked. Later, investigators prepared glutaraldehyde conjugates of specific amino acids in dilute BSA or brain homogenate solutions as positive controls in immune-electron microscopy studies12,13. More recent work investigated the use of gels made from formaldehyde-fixed protein solutions as surrogates for FFPE tissue in mass spectrometry analysis14. Another recent work investigated the structure and properties of gels formed by heating human or bovine serum albumin solutions at various concentrations and pH15. These authors found that serum albumin forms three types of gels differing in mechanical elasticity, secondary structure preservation, and fatty acid-binding capability depending on the experimental conditions. Together, these papers demonstrate the general feasibility of the approach employed here. Protein solutions of defined composition create tissue-like gels that can be further processed, sectioned, and stained using routine histological methods.
This protocol describes the formation of a synthetic IHC control made from bovine serum albumin (BSA) polymerized with heat and formaldehyde. The gels can incorporate a wide variety of antigens, including full-length proteins, protein domains, and linear peptides, as well as non-protein antigens&#160;including oligonucleotides2. This demonstration uses an example antigen&#160;a linear peptide encoding the C-terminal 16 amino acids of the human ERBB2 (HER2/neu) protein TPTAENPEYLGLDVPV-COOH (see Table of Materials). This sequence includes the epitopes recognized by three commercially available, diagnostically relevant antibodies&#160;including the Herceptest polyclonal reagent (ENPEYLGLDVP) and the monoclonal antibodies CB11 (AENPEYL) and 4B5 (TAENPEYLGL) (see Table of Materials)16.
The method demonstrated here employs readily available reagents using processes and techniques familiar to any practicing histology laboratory. The most significant limitation is the need to identify and purchase the target antigens, which can be accomplished in many cases at a relatively modest cost. Because these synthetic controls are of wholly defined composition and made with simple methods, they can be implemented in many laboratories with reproducible results. Their use may facilitate the objective, quantifiable evaluation of IHC staining results and allow greater intra- and inter-laboratory reproducibility.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Anti-HER2/neu clone 4B5</td>
			<td>Ventana</td>
			<td>5278368001</td>
			<td></td>
		</tr>
		<tr>
			<td>Biopsy Wraps</td>
			<td>Leica</td>
			<td>3801090</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin, ultra pure</td>
			<td>Cell Signaling Technology</td>
			<td>BSA #9998</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL Conical Tube</td>
			<td>Corning</td>
			<td>352070</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable base mold (15 mm x 15 mm)</td>
			<td>Fisher</td>
			<td>22-363-553</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable base mold 
			(24 mm x 24 mm)</td>
			<td>Fisher</td>
			<td>22-363-554</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable spatula</td>
			<td>VWR</td>
			<td>80081-188</td>
			<td></td>
		</tr>
		<tr>
			<td>Eppendorf Thermomixer</td>
			<td>Eppendorf</td>
			<td>22331</td>
			<td></td>
		</tr>
		<tr>
			<td>37% Formaldehyde</td>
			<td>Electron Microscopy Sciences</td>
			<td>15686</td>
			<td></td>
		</tr>
		<tr>
			<td>ERBB2 / HER2 peptide</td>
			<td></td>
			<td></td>
			<td>UniProt P04626-1; a.a. 1240-55</td>
		</tr>
		<tr>
			<td>Leica Autostainer XL</td>
			<td>Leica</td>
			<td>ST5010</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic Stir Bar</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NanoZoomer 2.0 HT whole slide imager</td>
			<td>Hamamatsu</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>10% Neutral Buffered Formalin</td>
			<td>VWR</td>
			<td>16004-128</td>
			<td></td>
		</tr>
		<tr>
			<td>Nuclease-free microfuge tubes 1.5 mL</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Paraplast paraffin</td>
			<td>Leica</td>
			<td>39601006</td>
			<td></td>
		</tr>
		<tr>
			<td>Peptide parameter calculator</td>
			<td>Pep-Calc17</td>
			<td>https://www.pep-calc.com/</td>
			<td></td>
		</tr>
		<tr>
			<td>Peptide suppliers</td>
			<td>ABclonal Science</td>
			<td></td>
			<td>Users should contact peptide vendors for details of mass, purity and cost.</td>
		</tr>
		<tr>
			<td></td>
			<td>Anaspec Peptide</td>
			<td></td>
			<td>Users should contact peptide vendors for details of mass, purity and cost.</td>
		</tr>
		<tr>
			<td></td>
			<td>CPC Scientific</td>
			<td></td>
			<td>Users should contact peptide vendors for details of mass, purity and cost.</td>
		</tr>
		<tr>
			<td></td>
			<td>New England Peptide</td>
			<td></td>
			<td>Users should contact peptide vendors for details of mass, purity and cost.</td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline pH 7.2</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Reagent Alcohol</td>
			<td>Thermo Scientific</td>
			<td>9111</td>
			<td></td>
		</tr>
		<tr>
			<td>Single Edge Razor</td>
			<td>VWR</td>
			<td>55411-050</td>
			<td></td>
		</tr>
		<tr>
			<td>Superfrost Plus positively charged microscope slides</td>
			<td>Thermo Scientific</td>
			<td>6776214</td>
			<td></td>
		</tr>
		<tr>
			<td>TMA Tissue Grand Master</td>
			<td>3DHISTECH</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Xylenes</td>
			<td>VWR</td>
			<td>89370-088</td>
			<td></td>
		</tr>
	</tbody>
</table>

synthetic antigen controls for immunohistochemistry

Immunohistochemistry (IHC) assays provide valuable insights into protein expression patterns, the reliable interpretation of which requires well-characterized positive and negative control samples. Because appropriate tissue or cell line controls are not always available, a simple method to create synthetic IHC controls may be beneficial. Such a method is described here. It is adaptable to various antigen types, including proteins, peptides, or oligonucleotides, in a wide range of concentrations. This protocol explains the steps necessary to create synthetic antigen controls, using as an example a peptide from the human erythroblastic oncogene B2 (ERBB2/HER2) intracellular domain (ICD) recognized by a variety of diagnostically relevant antibodies. Serial dilutions of the HER2 ICD peptide in bovine serum albumin (BSA) solution are mixed with formaldehyde and heated for 10 min at 85 &#176;C to solidify and cross-link the peptide/BSA mixture. The resulting gel can be processed, sectioned, and stained like a tissue, yielding a series of samples of known antigen concentrations spanning a wide range of staining intensities.
This simple protocol is consistent with routine histology lab procedures. The method requires only that the user have a sufficient quantity of the desired antigen. Recombinant proteins, protein domains, or linear peptides that encode relevant epitopes may be synthesized locally or commercially. Laboratories generating in-house antibodies can reserve aliquots of the immunizing antigen as the synthetic control target. The opportunity to create well-defined positive controls across a wide range of concentrations allows users to assess intra- and inter-laboratory assay performance, gain insight into the dynamic range and linearity of their assays, and optimize assay conditions for their particular experimental goals.

Peptides should dissolve entirely in an appropriate solvent at room temperature to form an optically clear solution. If visible particulate material is still present after 30-60 min, it may be helpful to add additional volumes of the original solvent or an alternative solvent not exceeding the intended volume of the 5x peptide stock solution calculated in Table 1. Likewise, the combined peptide/BSA solution should remain translucent (Figure 1A).
P...

Watch this Scientific Journal Video about Synthetic Antigen Controls for Immunohistochemistry at JoVE.com

Synthetic Antigen Controls for Immunohistochemistry

This work documents a simple method to create synthetic antigen controls for immunohistochemistry. The technique is adaptable to a variety of antigens in a wide range of concentrations. The samples provide a reference with which to assess intra- and inter-assay performance and reproducibility.

Immunohistochemistry (IHC) assays provide valuable insights into protein expression patterns, the reliable interpretation of which requires ...

BSA antigen gels are well-characterized reproducible IHC standards that can supplement existing controls. This protocol uses standard histology and IHC reagents and methods to make reproducible standards of known composition. These controls provide the opportunity for different labs to calibrate and standardize IHC assays for many diagnostically relevant assays.It is important to find a suitable solvent to dissolve the peptide or protein. It can be tricky to mix antigen and formaldehyde solutions quickly without introducing bubbles. To begin, prepare 20 milliliters of a 25%weight by volume BSA solution by mixing five grams of BSA powder in 14 milliliters of PBS, in a 50 milliliter conical tube until evenly distributed.Vortex the solution to dissolve the BSA powder. Keep the solution overnight at four degrees Celsius for complete dissolution. The following day, adjust the final volume to 20 milliliters with PBS.Similarly, prepare 20 milliliters of a 31.3%weight by volume BSA solution by mixing 6.26 grams of BSA powder in 13 milliliters of PBS. After overnight incubation for complete dissolution, adjust the final volume to 20 milliliters with PBS. To test that the BSA formaldehyde mixture forms a gel, preheat a heat block to 85 degrees Celsius.Then mix 700 microliters of the 25%BSA solution with 700 microliters of 37%formaldehyde. Mix well by pipetting up and down five times within five to 10 seconds without creating air bubbles. Immediately after mixing, place the closed micro centrifuge tube in the heat block preheated to 85 degrees Celsius.After 10 minutes, remove the tube from the heat block. Allow it to cool and confirm that the gel has formed as expected. Prepare and clearly label eight 1.5 milliliter micro centrifuge tubes.Then prepare a 5x peptide stock solution, add a 12.5 millimolar concentration by resuspending the entire mass of the liberalized peptide in 60 microliters of the appropriate solvent. Observe the solution to ensure that the peptide is completely dissolved. Then add an additional volume of solvent as necessary to make a 12.5 millimolar solution according to the peptides molecular weight, mass, and purity.In this example, the 5x peptide stock has a final volume of 626.9 microliters. Other peptide samples will require a different final volume. Next, prepare 150 microliters of a 1x peptide stock solution add a 2.5 millimolar concentration by diluting 30 microliters of the 5x peptide stock into 120 microliters of the solvent.Vortex the solution for five seconds and centrifuge at room temperature. Next, prepare 700 microliters of a 0.5 millimolar peptide BSA solution by diluting 140 microliters of the 1x peptide stock into 560 microliters of the 31.3%BSA solution. After vortexing, centrifuge the solution at room temperature.Similarly, prepare four successive 10x serial dilution of the peptide BSA stock by adding 70 microliters of the peptide BSA solution to 630 microliters of the 25%BSA solution. To prepare the BSA peptide gels, add 37%formaldehyde to the peptide BSA dilutions in a one to one ratio working one sample at a time. Mix well by pipetting up and down five times within five to 10 seconds without creating air bubbles.After mixing, place the closed micro centrifuge tube in a heat block at 85 degrees Celsius for 10 minutes. After all the peptide BSA and formaldehyde solutions have been prepared and heated, allow the gels to cool on the benchtop for five to 10 minutes. Next, using a clean, flexible disposable laboratory spatula, remove the gel sample from the micro centrifuge tube in one piece.And place it in a sealed container containing at least 15 milliliters of neutral buffered formalin, using a separate container for each sample. Alternatively, using a new single edge razor blade, cut off the bottom of the micro centrifuge tube and push the gel out from the bottom with air or a suitable probe. Using a clean single edged razor trim the gel cone into cylindrical discs approximately five millimeters thick.After wrapping the discs in a biopsy wrap, place one larger gel disc into one cassette and the remaining gel discs together into a second cassette for use in tissue microarray construction. Before processing, place the cassette gels in at least 15 milliliters of 10%neutral buffered formalin per gel, using a separate container for each sample. Next, process the gels in an automated histology tissue processor following a large tissue schedule with pressure and vacuum.When the sample processing is complete, remove the cassettes from the tissue processor and move them to the paraffin embedding center. After unwrapping the gels from the biopsy wrap, embed the gels in paraffin or each sample embed one disc of gel in a small 15 by 15 millimeter mold. And the remaining gel discs together in a second larger mold.For each peptide dilution series, create two glass slides containing a total of six separate sections. One section from each of the five dilution series samples and one section from the BSA only negative control sample. After sectioning and drying the slides, stain the two slides prepared for each peptide with the desired primary antibody.According to standard Immunohistochemistry protocols expect to see a relatively uniform signal within each gel section. With the different gel samples showing a range of signal intensity corresponding to the peptide dilutions. For the BSA gel tissue microarray construction, cut four micrometer thick sections of the tissue microarray and stain with a rabbit monoclonal antibody according to laboratory standard protocols.Assess the resulting stain intensity qualitatively by inspection or quantitatively buy digital image scanning and analysis. After reacting with the appropriate antibodies, negative control BSA only gel samples showed minimal signal. The signal intensity in an individual gel sample is relatively uniform and increases with increasing antigen concentrations.More than 10%of MDA-MB-175 cells show faint and in completely circumferential membranous staining. In contrast, more than 10%of the SKBR-3 cells, show intense completely circumferential membranous staining Work quickly once the formaldehyde has been added because the solutions will begin to gel even at room temperature. We use this method to make IHC controls when testing new antibodies to give us confidence that the assay performed as expected, even when the test antibodies show no signal.Tissue or cell line controls are inherently variable. Synthetic antigen controls allow us to measure the effect of changing specific ISD reaction conditions more precisely.

synthetic-antigen-controls-for-immunohistochemistry

Research

JoVE Journal

Medicine

Using Visual and Narrative Methods to Achieve Fair Process in Clinical Care

The Institute of Medicine has targeted patient-centeredness as an important area of quality improvement. A major dimension of patient-centeredness is respect for patient's values, preferences, and expressed needs. Yet specific approaches to gaining this understanding and translating it to quality care in the clinical setting are lacking. From a patient perspective quality is not a simple concept but is best understood in terms of five dimensions: technical outcomes; decision-making efficiency; amenities and convenience; information and emotional support; and overall patient satisfaction. Failure to consider quality from this five-pronged perspective results in a focus on medical outcomes, without considering the processes central to quality from the patient's perspective and vital to achieving good outcomes. In this paper, we argue for applying the concept of fair process in clinical settings. Fair process involves using a collaborative approach to exploring diagnostic issues and treatments with patients, explaining the rationale for decisions, setting expectations about roles and responsibilities, and implementing a core plan and ongoing evaluation. Fair process opens the door to bringing patient expertise into the clinical setting and the work of developing health care goals and strategies. This paper provides a step by step illustration of an innovative visual approach, called photovoice or photo-elicitation, to achieve fair process in clinical work with acquired brain injury survivors and others living with chronic health conditions. Applying this visual tool and methodology in the clinical setting will enhance patient-provider communication; engage patients as partners in identifying challenges, strengths, goals, and strategies; and support evaluation of progress over time. Asking patients to bring visuals of their lives into the clinical interaction can help to illuminate gaps in clinical knowledge, forge better therapeutic relationships with patients living with chronic conditions such as brain injury, and identify patient-centered goals and possibilities for healing. The process illustrated here can be used by clinicians, (primary care physicians, rehabilitation therapists, neurologists, neuropsychologists, psychologists, and others) working with people living with chronic conditions such as acquired brain injury, mental illness, physical disabilities, HIV/AIDS, substance abuse, or post-traumatic stress, and by leaders of support groups for the types of patients described above and their family members or caregivers.

This paper illustrates an innovative visual approach (photovoice or photo-elicitation) to achieve fair process in clinical care for patients living with chronic health conditions, illuminate gaps in clinical knowledge, forge better therapeutic relationships, and identify patient-centered goals and possibilities for healing.

The Institute of Medicine has targeted patient-centeredness as an important area of quality improvement. A major dimension of patient-centeredness is ...

Modeling Stroke in Mice - Middle Cerebral Artery Occlusion with the Filament Model

Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are very limited. To meet the need for novel therapeutic approaches, experimental stroke research frequently employs rodent models of focal cerebral ischaemia. Most researchers use permanent or transient occlusion of the middle cerebral artery (MCA) in mice or rats.
Proximal occlusion of the middle cerebral artery (MCA) via the intraluminal suture technique (so called filament or suture model) is probably the most frequently used model in experimental stroke research. The intraluminal MCAO model offers the advantage of inducing reproducible transient or permanent ischaemia of the MCA territory in a relatively non-invasive manner. Intraluminal approaches interrupt the blood flow of the entire territory of this artery. Filament occlusion thus arrests flow proximal to the lenticulo-striate arteries, which supply the basal ganglia. Filament occlusion of the MCA results in reproducible lesions in the cortex and striatum and can be either permanent or transient. In contrast, models inducing distal (to the branching of the lenticulo-striate arteries) MCA occlusion typically spare the striatum and primarily involve the neocortex. In addition these models do require craniectomy. In the model demonstrated in this article, a silicon coated filament is introduced into the common carotid artery and advanced along the internal carotid artery into the Circle of Willis, where it blocks the origin of the middle cerebral artery. In patients, occlusions of the middle cerebral artery are among the most common causes of ischaemic stroke. Since varying ischemic intervals can be chosen freely in this model depending on the time point of reperfusion, ischaemic lesions with varying degrees of severity can be produced. Reperfusion by removal of the occluding filament at least partially models the restoration of blood flow after spontaneous or therapeutic (tPA) lysis of a thromboembolic clot in humans.
In this video we will present the basic technique as well as the major pitfalls and confounders which may limit the predictive value of this model.

Filamentous occlusion of the Middle cerebral artery is a common model for studying ischemic stroke in mice.

Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are ...

Enhancement of Apoptotic and Autophagic Induction by a Novel Synthetic C-1 Analogue of 7-deoxypancratistatin in Human Breast Adenocarcinoma and Neuroblastoma Cells with Tamoxifen

Breast cancer is one of the most common cancers amongst women in North America. Many current anti-cancer treatments, including ionizing radiation, induce apoptosis via DNA damage. Unfortunately, such treatments are non-selective to cancer cells and produce similar toxicity in normal cells. We have reported selective induction of apoptosis in cancer cells by the natural compound pancratistatin (PST). Recently, a novel PST analogue, a C-1 acetoxymethyl derivative of 7-deoxypancratistatin (JCTH-4), was produced by de novo synthesis and it exhibits comparable selective apoptosis inducing activity in several cancer cell lines. Recently, autophagy has been implicated in malignancies as both pro-survival and pro-death mechanisms in response to chemotherapy. Tamoxifen (TAM) has invariably demonstrated induction of pro-survival autophagy in numerous cancers. In this study, the efficacy of JCTH-4 alone and in combination with TAM to induce cell death in human breast cancer (MCF7) and neuroblastoma (SH-SY5Y) cells was evaluated. TAM alone induced autophagy, but insignificant cell death whereas JCTH-4 alone caused significant induction of apoptosis with some induction of autophagy. Interestingly, the combinatory treatment yielded a drastic increase in apoptotic and autophagic induction. We monitored time-dependent morphological changes in MCF7 cells undergoing TAM-induced autophagy, JCTH-4-induced apoptosis and autophagy, and accelerated cell death with combinatorial treatment using time-lapse microscopy. We have demonstrated these compounds to induce apoptosis/autophagy by mitochondrial targeting in these cancer cells. Importantly, these treatments did not affect the survival of noncancerous human fibroblasts. Thus, these results indicate that JCTH-4 in combination with TAM could be used as a safe and very potent anti-cancer therapy against breast cancer and neuroblastoma cells.

We have synthesized a novel analogue of pancratistatin with comparable anti-cancer activity as native pancratistatin; interestingly, combinatory treatment with tamoxifen yielded a drastic enhancement in apoptotic and autophagic induction by mitochondrial targeting with minimal effect on noncancerous fibroblasts. Thus, JCTH-4 in combination with tamoxifen could provide a safe anti-cancer therapy.

Breast cancer is one of the most common cancers amongst women in North America. Many current anti-cancer treatments, including ionizing radiation, induce ...

Sequential In vivo Imaging of Osteogenic Stem/Progenitor Cells During Fracture Repair

Bone turns over continuously and is highly regenerative following injury. Osteogenic stem/progenitor cells have long been hypothesized to exist, but in vivo demonstration of such cells has only recently been attained. Here, in vivo imaging techniques to investigate the role of endogenous osteogenic stem/progenitor cells (OSPCs) and their progeny in bone repair are provided. Using osteo-lineage cell tracing models and intravital imaging of induced microfractures in calvarial bone, OSPCs can be directly observed during the first few days after injury, in which critical events in the early repair process occur. Injury sites can be sequentially imaged revealing that OSPCs relocate to the injury, increase in number and differentiate into bone forming osteoblasts. These methods offer a means of investigating the role of stem cell-intrinsic and extrinsic molecular regulators for bone regeneration and repair.

Sequential In vivo Imaging of Osteogenic Stem/Progenitor Cells During Fracture Repair

Quantitative measurement of bone progenitor function in fracture healing requires high resolution serial imaging technology. Here, protocols are provided for using intravital microscopy and osteo-lineage tracking to sequentially image and quantify the migration, proliferation and differentiation of endogenous osteogenic stem/progenitor cells in the process of repairing bone fracture.

Bone turns over continuously and is highly regenerative following injury. Osteogenic stem/progenitor cells have long been hypothesized to exist, but in ...

Modeling and Simulations of Olfactory Drug Delivery with Passive and Active Controls of Nasally Inhaled Pharmaceutical Aerosols

There are many advantages of direct nose-to-brain drug delivery in the treatment of neurological disorders. However, its application is limited by the extremely low delivery efficiency (&#60; 1%) to the olfactory mucosa that directly connects the brain. It is crucial to develop novel techniques to deliver neurological medications more effectively to the olfactory region. The objective of this study is to develop a numerical platform to simulate and improve intranasal olfactory drug delivery. A coupled image-CFD method was presented that synthetized the image-based model development, quality meshing, fluid simulation, and magnetic particle tracking. With this method, performances of three intranasal delivery protocols were numerically assessed and compared. Influences of breathing maneuvers, magnet layout, magnetic field strength, drug release position, and particle size on the olfactory dosage were also numerically studied.
From the simulations, we found that clinically significant olfactory dosage (up to 45%) were feasible using the combination of magnet layout and selective drug release. A 64 -fold higher delivery of dosage was predicted in the case with magnetophoretic guidance compared to the case without it. However, precise guidance of nasally inhaled aerosols to the olfactory region remains challenging due to the unstable nature of magnetophoresis, as well as the high sensitivity of olfactory dosage to patient-, device-, and particle-related factors.

This manuscript reviews the modeling and simulations of different protocols to deliver medications to the olfactory region in image-based nasal airway models. Multiple software modules are used to develop the anatomically accurate nose model, generate computational mesh, simulate nasal airflows, and predict particle deposition at the olfactory region.

There are many advantages of direct nose-to-brain drug delivery in the treatment of neurological disorders. However, its application is limited by the ...

Quantitative Immunohistochemistry of the Cellular Microenvironment in Patient Glioblastoma Resections

With the growing interest in the tumor microenvironment, we set out to develop a method to specifically determine the microenvironment components within patient samples of glioblastoma, the deadliest and most invasive brain cancer. Not only are quantitative methods beneficial for accurately describing diseased tissues, they can also potentially contribute to more accurate prognosis, diagnosis, and the development of tissue-engineered systems and replacements. In glioblastoma, glial cells, such as microglia and astrocytes, have been independently correlated with poor prognosis based on pathologist grading. However, the state of these cells and other glial cell components has not been well-described quantitatively. This can be difficult due to the large processes that mark these glial cells. Furthermore, most histological analyses focus on the overall tissue sample or only within the bulk of the tumor, as opposed to delineating quantifications based on regions within the highly heterogeneous tissue. Here, we describe a method for identifying and quantitatively analyzing the populations of glial cells within the tumor bulk and adjacent regions of tumor resections from glioblastoma patients. We used chromogenic immunohistochemistry to identify the glial cell populations in patient tumor resections and ImageJ to analyze percent coverage of staining for each glial population. With these techniques we are able to better describe the glial cells throughout regions of the glioma tumor microenvironment.

This protocol was developed to quantitatively identify tumor microenvironment components in glioblastoma patient resections using chromogenic immunohistochemistry and ImageJ.

With the growing interest in the tumor microenvironment, we set out to develop a method to specifically determine the microenvironment components within ...

Accelerating Tuberculosis Determination Using the Micro-CFU Method

Micro-Colony Forming Unit Assay for Efficacy Evaluation of Vaccines Against Tuberculosis

Tuberculosis (TB), the leading cause of death worldwide by an infectious agent, killed 1.6 million people in 2022, only being surpassed by COVID-19 during the 2019-2021 pandemic. The disease is caused by the bacterium Mycobacterium tuberculosis (M.tb). The Mycobacterium bovis strain Bacillus Calmette-Gu&#233;rin (BCG), the only TB vaccine, is the oldest licensed vaccine in the world, still in use. Currently, there are 12 vaccines in clinical trials and dozens of vaccines under pre-clinical development. The method of choice used to assess the efficacy of TB vaccines in pre-clinical studies is the enumeration of bacterial colonies by the colony-forming units (CFU) assay. This time-consuming assay takes 4 to 6 weeks to conclude, requires substantial laboratory and incubator space, has high reagent costs, and is prone to contamination. Here we describe an optimized method for colony enumeration, the micro-CFU (mCFU), that offers a simple and rapid solution to analyze M.tb vaccine efficacy results. The mCFU assay requires tenfold fewer reagents, reduces the incubation period threefold, taking 1 to 2 weeks to conclude, reduces lab space and reagent cost, and minimizes the health and safety risks associated with working with large numbers of M.tb. Moreover, to evaluate the efficacy of a TB vaccine, samples may be obtained from a variety of sources, including tissues from vaccinated animals infected with Mycobacteria. We also describe an optimized method to produce a unicellular, uniform, and high-quality mycobacterial culture for infection studies. Finally, we propose that these methods should be universally adopted for pre-clinical studies of vaccine efficacy determination, ultimately leading to time reduction in the development of vaccines against TB.

Author Spotlight: Optimizing CFU Determination for Efficient Assessment of TB Vaccine Efficacy and Antigen Presentation Analysis 

The determination of colony-forming units (CFU) is the gold-standard technique for quantifying bacteria, including Mycobacterium tuberculosis which can take weeks to form visible colonies. Here we describe a micro-CFU for CFU determination with increased time efficiency, reduced lab space and reagent cost, and scalability to medium and high throughput experiments.

Tuberculosis (TB), the leading cause of death worldwide by an infectious agent, killed 1.6 million people in 2022, only being surpassed by COVID-19 during ...

Automated Processor for Clinical-Scale CAR-T Cell Manufacturing

Chimeric Antigen Receptor T Cell Manufacturing on an Automated Cell Processor

Chimeric antigen receptor (CAR)-T cells represent a promising immunotherapeutic approach for the treatment of various malignant and non-malignant diseases. CAR-T cells are genetically modified T cells that express a chimeric protein that recognizes and binds to a cell surface target, resulting in the killing of the target cell. Traditional CAR-T cell manufacturing methods are labor-intensive, expensive, and may carry the risk of contamination. The CliniMACS Prodigy, an automated cell processor, allows for manufacturing cell therapy products at a clinical scale in a closed system, minimizing the risk of contamination. Processing occurs semi-automatically under the control of a computer and thus&#160;minimizes human involvement in the process, which saves time and reduces variability and errors.
This manuscript and video describes the T cell transduction (TCT) process for manufacturing CAR-T cells using this processor. The TCT process involves CD4+/CD8+ T cell enrichment, activation, transduction with a viral vector, expansion, and harvest. Using the Activity Matrix, a functionality that allows ordering and timing of these steps, the TCT process can be customized extensively. We provide a walk-through of CAR-T cell manufacturing in compliance with current Good Manufacturing Practice&#160;(cGMP) and discuss required release testing and preclinical experiments that will support an Investigational New Drug (IND) application. We demonstrate&#160;the feasibility and discuss the advantages and disadvantages of using a&#160;semi-automatic process for clinical CAR-T cell manufacturing. Finally, we describe an ongoing investigator-initiated clinical trial that targets pediatric B-cell malignancies [NCT05480449] as an example of how this manufacturing process can be applied in a clinical setting.

Author Spotlight: Advancements in CAR-T Cell Manufacturing and Gene Therapy Production 

This article details the manufacturing process for chimeric antigen receptor T cells for clinical use, specifically using an automated cell processor capable of performing viral transduction and cultivation of T cells. We provide recommendations and describe pitfalls that should be considered during the process development and implementation of an early-phase clinical trial.

Chimeric antigen receptor (CAR)-T cells represent a promising immunotherapeutic approach for the treatment of various malignant and non-malignant ...

Manufacturing Chimeric Antigen Receptor T-Cells Using an Automated Cell Processor

Begin by turning on the instrument and selecting the T-cell transduction process from the touchscreen interface. Click run to initiate the procedure and follow the onscreen instructions provided. On the perimeter input screen input the operator initials tubing set, lot number, and expiration date.Next, select full process on the process setup screen. Now, choose two vials of selection reagent for the CD4, CD8 selection method. Install the tubing set, ensuring that all lure connections are tightly set and complete the upper and lower integrity tests by following the instructions on the touchscreen.Now, attach the medium and processing buffer bags per the onscreen guidance and begin the automatic priming of the tubing set. Once the transfer cell product screen appears, transfer the thawed T-cell product to a 150 milliliter transfer bag and sterile weld it to the application bag of the tubing set. Next, use a quality control pouch to obtain a sample from the application bag and perform a cell count using a hematology analyzer.Connect the CD4 and CD8 reagent vials to the tubing set and start the selection process for T-cell enrichment. After enrichment, remove a sample of the selected cells from the reapplication bags quality control pouch. Enter the desired cell concentration and starting number.Now, attach a vial of the activation reagent according to onscreen instructions. Then, set the carbon dioxide concentration to 5%and the culture chamber temperature to 39 degrees Celsius. Establish the activity matrix using the enhanced feeding protocol as a starting point and modify individual steps to your specific optimized protocol.In this case, set the transduction activity time to 24 hours after seeding and the culture wash to 48 hours after transduction. Set the activate shaker time to begin 30 minutes after starting the culture wash. Delete any medium bag exchange and waste bag exchange activities as they are no longer required.Then, press okay on the screen to initiate cultivation. Allow the instrument to automatically pump the required volume from the reapplication bag into the culture chamber. Thaw and prepare the calculated vector volume in a 20 milliliter reagent bag with a cold medium to reach a final volume of 10 milliliters.Adjust the activity matrix to set the transduction time to two minutes into the future and press okay to initiate the transduction activity. Sterile weld the vector bag to the tubing set following the onscreen instructions. Modify the activity matrix according to the actual transduction start time with the culture wash scheduled 48 hours after transduction.Schedule the time of activate shaker to 30 minutes after the culture wash. Finally, ensure the media exchange occurs in the afternoon at 2:00 PM on day six. Press the sample button and follow the onscreen instructions to acquire a quality control sample from the active culture.Divide the sample into three one milliliter aliquots for various analyses. Prepare the final formulation buffer, saving a portion for the cryoprotectant preparation later. Next, adjust the activity matrix, setting the end of culture to two minutes in the future.Attach the final formulation buffer to the tubing set and begin harvest. Seal off and remove the target cell bag. This bag contains the CAR T-cells ready for infusion or cryo-preservation.RT runs of the clinical trial was 46%This indicates that the TCT process effectively promoted cell expansion. The cell viability of the final product was between 88 to 94%and the CD3 T-cell purity was 89 to 93%Endotoxin, mycoplasma, sterility, replication competent lentivirus, and residual leukemic cells were not detectable.

A Comprehensive Step-By-Step Guide for Exclusive Endoscopic Ossiculoplasty

Techniques of Endoscopic Ossiculoplasty

The utilization of endoscopes in modern otology has evolved from diagnostic purposes to the development of exclusive endoscopic ear surgery. This technique offers a panoramic view of the middle ear and provides an optimal magnification of the oval window region, the stapes' suprastructure, and the footplate, allowing great precision in prosthesis positioning during ossiculoplasty (OPL). Various techniques for ossicular chain reconstruction have been described in the literature. Either autologous or synthetic materials can be used for reconstruction. The use of a patient's own tissue minimizes the risk of implant rejection or extrusion of the prosthesis through the tympanic membrane. On the other hand, synthetic materials like titanium are light and rigid and do not require time-consuming prosthesis remodeling. The main objective of this article is to present a comprehensive step-by-step guide that serves as a surgical manual for exclusive endoscopic OPL. This guide will explain various forms of OPL using synthetic and autologous materials. The goal is to provide a comprehensive understanding of the various surgical techniques and support the integration into clinical practice.

Author Spotlight: Advancing Endoscopic Ossiculoplasty &amp;#8211; Techniques, Innovations, and Practical Guidance for Clinical Integration

Exclusive Endoscopic ossiculoplasty (EEO) is a promising and minimally invasive approach for the treatment of conductive hearing loss due to ossicular chain disruptions and associated middle ear pathologies. Herein, step-by-step instructions and a discussion of various endoscopic ossiculoplasty techniques are presented.