Editing Microtome (section)

==Applications==
[[File:Microtome1905.JPG|thumb|Microtome (C. Reichert, Vienna, 1905–1915)]]

The most common applications of '''microtomes''' are:
* Traditional [[histological|Histology]] Technique: tissues are fixed, dehydrated, cleared, and embedded in melted [[Paraffin wax|paraffin]], which when cooled forms a solid block. The tissue is then cut in the microtome at thicknesses varying from 2 to 50&nbsp;μm. From there the tissue can be mounted on a microscope slide, stained with appropriate aqueous dye(s) after removal of the paraffin, and examined using a light microscope.<ref name="Bancroft and Stevens, 1982" />
* [[Frozen section procedure]]: water-rich tissues are hardened by freezing and cut in the frozen state with a freezing microtome or microtome-[[cryostat]]; sections are stained and examined with a light microscope. This technique is much faster than traditional histology (5 minutes vs 16 hours) and is used in conjunction with medical procedures to achieve a quick diagnosis. Cryosections can also be used in [[immunohistochemistry]] as freezing tissue stops degradation of tissue faster than using a [[fixation (histology)|fixative]] and does not alter or mask its chemical composition as much. 
* [[Electron Microscopy]] Technique: after embedding tissues in epoxy resin, a microtome equipped with a glass or gem grade diamond knife is used to cut very thin sections (typically 60 to 100 nanometer). Sections are stained with an aqueous solution of an appropriate heavy metal salt and examined with a [[transmission electron microscope]]. This instrument is often called an ''ultramicrotome''.  The ultramicrotome is also used with its glass knife or an industrial grade diamond knife to cut survey sections prior to thin sectioning.  These survey sections are generally 0.5 to 1&nbsp;μm thick and are mounted on a glass slide and stained to locate areas of interest under a light microscope prior to thin sectioning for the TEM.  Thin sectioning for the TEM is often done with a gem quality diamond knife.  Complementing traditional TEM techniques ultramicrotomes are increasingly found mounted inside an SEM chamber so the surface of the block face can be imaged and then removed with the microtome to uncover the next surface for imaging.  This technique is called [[serial block-face scanning electron microscopy]] (SBFSEM). 
* Botanical Microtomy Technique: hard materials like wood, bone and leather require a [[Microtome#Sledge microtome|sledge microtome]]. These microtomes have heavier blades and cannot cut as thin as a regular microtome.
* [[Spectroscopy]] (especially [[FTIR]] or [[infrared spectroscopy]]) Technique: thin polymer sections are needed in order that the infra-red beam can penetrate the sample under examination. It is normal to cut samples to between 20 and 100&nbsp;μm in thickness. For more detailed analysis of much smaller areas in a thin section, FTIR [[microscopy]] can be used for sample inspection.

A recent development is the [[laser microtome]], which cuts the target specimen with a [[femtosecond laser]] instead of a mechanical knife. This method is contact-free and does not require sample preparation techniques. The laser microtome has the ability to slice almost every tissue in its native state. Depending on the material being processed, slice thicknesses of 10 to 100&nbsp;μm are feasible.

{{anchor|Intervals}}Sectioning intervals can be classified mainly into either:
*Serial sectioning: obtaining a continuous ribbon of sections from a paraffin block and using all for slides. 
*Step sections: collected at specified depths in the block.

===Precision cut kidney slices===
'''Precision-cut kidney slices''' refer to thin sections of the kidney tissue that are prepared using a microtome to study kidney functions, drug metabolism or disease processes. Researchers use these slices to study the impact of substances on renal function.<ref>{{Cite journal |last1=Poosti |first1=Fariba |last2=Pham |first2=Bao Tung |last3=Oosterhuis |first3=Dorenda |last4=Poelstra |first4=Klaas |last5=van Goor |first5=Harry |last6=Olinga |first6=Peter |last7=Hillebrands |first7=Jan-Luuk |date=2015-01-01 |title=Precision-cut kidney slices (PCKS) to study development of renal fibrosis and efficacy of drug targeting ''ex vivo'' |url=http://dx.doi.org/10.1242/dmm.020172 |journal=Disease Models & Mechanisms |volume=8 |issue=10 |pages=1227–1236 |doi=10.1242/dmm.020172 |pmid=26112172 |pmc=4610232 |issn=1754-8411}}</ref><ref>{{cite journal | doi=10.4137/BMI.S38439 | title=Precision-Cut Kidney Slices as a Tool to Understand the Dynamics of Extracellular Matrix Remodeling in Renal Fibrosis | date=2016 | last1=Genovese | first1=Federica | last2=Kàrpàti | first2=Zsolt S. | last3=Nielsen | first3=Signe H. | last4=Karsdal | first4=Morten A. | journal=Biomarker Insights | volume=11 | pages=77–84 | pmid=27257368 | pmc=4877083 }}</ref> This includes drug metabolism<ref>{{cite journal | url=https://www.tandfonline.com/doi/abs/10.1517/17425255.3.6.879 | doi=10.1517/17425255.3.6.879 | title=Precision-cut tissue slices as a tool to predict metabolism of novel drugs | date=2007 | last1=Graaf | first1=Inge AM de | last2=Groothuis | first2=Geny MM | last3=Olinga | first3=Peter | journal=Expert Opinion on Drug Metabolism & Toxicology | volume=3 | issue=6 | pages=879–898 | pmid=18028031 | s2cid=36518505 | url-access=subscription }}</ref><ref>{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S0887233399000478 | doi=10.1016/S0887-2333(99)00047-8 | title=Organ Slices as an in Vitro Test System for Drug Metabolism in Human Liver, Lung and Kidney | date=1999 | last1=De Kanter | first1=R. | last2=Olinga | first2=P. | last3=De Jager | first3=M.H | last4=Merema | first4=M.T | last5=Meijer | first5=D.K.F | last6=Groothius | first6=G.M.M | journal=Toxicology in Vitro | volume=13 | issue=4–5 | pages=737–744 | pmid=20654543 | url-access=subscription }}</ref> and the effects of toxic substances.<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/002432059502176J | doi=10.1016/0024-3205(95)02176-J | title=Precision-cut tissue slices: Applications in pharmacology and toxicology | date=1995 | last1=Parrish | first1=Alan R. | last2=Gandolfi | first2=A.Jay | last3=Brendel | first3=Klaus | journal=Life Sciences | volume=57 | issue=21 | pages=1887–1901 | pmid=7475939 | url-access=subscription }}</ref>