The work was supported, in part, by the National Institute of Health Center of Biological Research Excellence [grant number 1P20GM109005], the Arkansas Space Grant Consortium through National Aeronautics and Space Administration [grant number NNX15AK32A], and the National Institute for Occupational Safety and Health (NIOSH) [grant number 2T420H008436]. The authors would like to thank Christopher Fettes for proofreading and editing this manuscript.

1. Particle Collection and Preparation
<ol>
	<li>Calibration of the high volume total suspended particles sampler
	<ol>
		<li>Disconnect the sampler motor from the mass flow controller and connect the motor to a stable AC power source (Figure 1). 
		NOTE: A filter is not used during this procedure.</li>
		<li>Mount the calibrator orifice and top loading adapter plate to the sampler. Tighten the top loading adapter hold-down nuts securely to ensure that no air leaks are present. Al...

<ol>
	<li>Lim, S. 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=A+comparative+risk+assessment+of+burden+of+disease+and+injury+attributable+to+67+risk+factors+and+risk+factor+clusters+in+21+regions,+1990-2010:+a+systematic+analysis+for+the+Global+Burden+of+Disease+Study+2010.">A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.</a> Lancet. 380, 2224-2260 (2012).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> IARC: Outdoor air pollution a leading environmental cause of cancer deaths. , (2013).</li><li>Putaud, 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=A+European+aerosol+phenomenology-2:+chemical+characteristics+of+particulate+matter+at+kerbside,+urban,+rural+and+background+sites+in+Europe.">A European aerosol phenomenology-2: chemical characteristics of particulate matter at kerbside, urban, rural and background sites in Europe.</a> Atmos. Environ. 38 (16), 2579-2595 (2004).</li><li>Hand, J., Schichtel, B., Pitchford, M., Malm, W., Frank, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Seasonal+composition+of+remote+and+urban+fine+particulate+matter+in+the+United+States.">Seasonal composition of remote and urban fine particulate matter in the United States.</a> J Geophys Res-Atmos. 117 (5), (2012).</li><li>Schauer, J. 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=Source+apportionment+of+airborne+particulate+matter+using+organic+compounds+as+tracers.">Source apportionment of airborne particulate matter using organic compounds as tracers.</a> Atmos. Environ. 30 (22), 3837-3855 (1996).</li><li>Simoneit, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+biomarker+compounds+as+source+indicators+and+tracers+for+air+pollution.">A review of biomarker compounds as source indicators and tracers for air pollution.</a> Environ. Sci. Pollut. Res. 6 (3), 159-169 (1999).</li><li>Kavouras, I. G., Stephanou, E. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Particle+size+distribution+of+organic+primary+and+secondary+aerosol+constituents+in+urban,+background+marine,+and+forest+atmosphere.">Particle size distribution of organic primary and secondary aerosol constituents in urban, background marine, and forest atmosphere.</a> J Geophys Res-Atmos. 107 (8), (2002).</li><li>Graber, E., Rudich, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atmospheric+HULIS:+How+humic-like+are+they?+A+comprehensive+and+critical+review.">Atmospheric HULIS: How humic-like are they? A comprehensive and critical review.</a> Atmos. Chem. Phys. 6 (3), 729-753 (2006).</li><li>P&#246;schl, 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=Atmospheric+aerosols:+composition,+transformation,+climate+and+health+effects.">Atmospheric aerosols: composition, transformation, climate and health effects.</a> Angew. Chem. Int. 44 (46), 7520-7540 (2005).</li><li>Hou, 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=Altered+methylation+in+tandem+repeat+element+and+elemental+component+levels+in+inhalable+air+particles.">Altered methylation in tandem repeat element and elemental component levels in inhalable air particles.</a> Environ. Mol. Mutagen. 55 (3), 256-265 (2014).</li><li>Miousse, I. R., 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=Epigenetic+alterations+induced+by+ambient+particulate+matter+in+mouse+macrophages.">Epigenetic alterations induced by ambient particulate matter in mouse macrophages.</a> Environ. Mol. Mutagen. 55 (5), 428-435 (2014).</li><li>Miousse, I. R., 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=In+Vitro+Toxicity+and+Epigenotoxicity+of+Different+Types+of+Ambient+Particulate+Matter.">In Vitro Toxicity and Epigenotoxicity of Different Types of Ambient Particulate Matter.</a> Toxicol. Sci. 148 (2), 473-487 (2015).</li><li>Ehrlich, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genomic+instability+in+cancer+development.">Genomic instability in cancer development.</a> Genome Instability in Cancer Development. , 363-392 (2005).</li><li>Michael, S., Montag, M., Dott, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pro-inflammatory+effects+and+oxidative+stress+in+lung+macrophages+and+epithelial+cells+induced+by+ambient+particulate+matter.">Pro-inflammatory effects and oxidative stress in lung macrophages and epithelial cells induced by ambient particulate matter.</a> Environ Pollut. 183, 19-29 (2013).</li><li>Li, 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=Induction+of+heme+oxygenase-1+expression+in+macrophages+by+diesel+exhaust+particle+chemicals+and+quinones+via+the+antioxidant-responsive+element.">Induction of heme oxygenase-1 expression in macrophages by diesel exhaust particle chemicals and quinones via the antioxidant-responsive element.</a> J Immunol. 165 (6), 3393-3401 (2000).</li><li>Pathak, R., Ramakumar, A., Subramanian, U., Prasanna, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+radio-sensitivities+of+human+chromosomes+1+and+2+in+one+donor+in+interphase-+and+metaphase-spreads+after+60Co+gamma-irradiation.">Differential radio-sensitivities of human chromosomes 1 and 2 in one donor in interphase- and metaphase-spreads after 60Co gamma-irradiation.</a> BMC Med. Phys. 9, 6649 (2009).</li><li>Pathak, R., Dey, S. K., Sarma, A., Khuda-Bukhsh, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genotoxic+effects+in+M5+cells+and+Chinese+hamster+V79+cells+after+exposure+to+7+Li-beam+(LET=+60keV/&#181;m)+and+correlation+of+their+survival+dynamics+to+nuclear+damages+and+cell+death.">Genotoxic effects in M5 cells and Chinese hamster V79 cells after exposure to 7 Li-beam (LET= 60keV/&#181;m) and correlation of their survival dynamics to nuclear damages and cell death.</a> Mutat. Res. Genet. Toxicol. Environ. Mutagen. 628 (1), 56-66 (2007).</li><li>Pathak, R., Dey, S. K., Sarma, A., Khuda-Bukhsh, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+killing,+nuclear+damage+and+apoptosis+in+Chinese+hamster+V79+cells+after+irradiation+with+heavy-ion+beams+of+16+O,+12+C+and+7+Li.">Cell killing, nuclear damage and apoptosis in Chinese hamster V79 cells after irradiation with heavy-ion beams of 16 O, 12 C and 7 Li.</a> Mutat. Res. Genet. Toxicol. Environ. Mutagen. 632 (1), 58-68 (2007).</li><li>Chalbot, M. C., Kavouras, I. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+magnetic+resonance+spectroscopy+for+determining+the+functional+content+of+organic+aerosols:+a+review.">Nuclear magnetic resonance spectroscopy for determining the functional content of organic aerosols: a review.</a> Environ. Pollut. 191, 232-249 (2014).</li></ol>

Cytogenetic study or microscopic analysis of the numbers or structures of chromosomes, primarily in metaphase spreads, provides information crucial for prognosis, risk assessment, and treatment for various diseases. It is now well-established that cytogenetic abnormalities are linked with the progression and development of several diseases, including cancer. To date, CAs have been found in all major tumor types. CAs may arise spontaneously or by either external or internal stimuli, such as ionizing radiation (IR) &#8212;...

It has been estimated that exposure to particulate matter (PM) causes over 3 million excess deaths annually, primarily from cardiopulmonary disease and lung cancer1. Indeed, PM was recognized as carcinogenic to humans by the International Agency for Research on Cancer (Group 1), as an increased risk of lung cancer with increasing levels of exposure to PM has been shown2. Interestingly, almost all the cancer cells harbor numerical and/or structural chromosomal abnormalities. Particulate organic carbon is a variant, complex, and heterogeneous mixture, whose composition and size distribution depends on emissions as well as physical and chemical transformations. It accounts from 35-55% of urban PM2.5 mass (PM 2.5 &#181;m in size and smaller) and more than 60% of rural and continental background PM2.5 mass3, 4. The water soluble fraction accounts for 30-90% of organic aerosol. A large number of organic compounds have been identified, including aliphatic hydrocarbons, polycyclic aromatic hydrocarbons, and their oxygenated and nitrated derivatives, aliphatic aldehydes and alcohols, free fatty acids and their salts, di-carboxylic acids, multifunctional compounds, proteins, and humic-like macromolecules (HULIS) using chromatographic methods coupled with mass spectrometric techniques5-8. These compounds represent less than 10-20% of particulate organic carbon, thus most of organic carbon is unknown9.
Experimental evidence suggests that cytotoxicity, oxidative stress, and inflammation are involved in the development of PM-associated pathological states. It has been recently shown, however, that exposure to PM also results in a number of epigenetic alterations, including alterations in DNA methylation of repetitive elements, in both experimental in vitro systems and in human subjects10-12. Of particular interest are the effects of PM on satellite DNA &#8212; major and minor satellites &#8212; which are found in the heterochromatic region around the centromere of chromosomes. It was shown that these effects may be persistent by nature, as they can be detected for at least 72 hr after exposure12. Alterations in DNA methylation, particularly around centromeres, may lead to accumulation of satellite DNA mRNA transcripts, compromise chromosomal integrity during cell division and, subsequently, result in the development of a variety of pathological states13.
Adaptation of cytogenetic approach for the analysis of CAs as an end-point of epigenetic alterations caused by PM, thus, is of high importance. Here, we report the approach for the ambient PM collection and preparation, in vitro exposure and analysis of CAs using the murine macrophage RAW264.7 model system. Macrophages comprise the first line of defense against the inhaled foreign objects and, therefore, this cell line serves as an established and the most frequently used model in particle toxicology11, 12, 14, 15.

<table border="0" cellpadding="0" cellspacing="0" width="726">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Total suspended particulate sampler</td>
			<td style="width:179px;">Tisch Environmental</td>
			<td style="width:119px;">TE-5170</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:261px;">Bruker Avance III NMR spectrometer&#160;</td>
			<td style="width:179px;">Bruker</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">TopSpin 3.5/pl2 software</td>
			<td style="width:179px;">Bruker</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:261px;">ACD/NMR Processor Academic Edition</td>
			<td style="width:179px;">ACD/Labs</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RAW264.7 murine macrophages</td>
			<td style="width:179px;">ATCC</td>
			<td style="width:119px;">ATCC TIB-71</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:261px;">High glucose DMEM GlutaMAX media</td>
			<td style="width:179px;">ThermoFisher</td>
			<td align="right" style="width:119px;">10569010</td>
			<td>Warm in a 37&#176;C waterbath before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Fetal Bovine Serum</td>
			<td style="width:179px;">ThermoFisher</td>
			<td align="right" style="width:119px;">16000044</td>
			<td>Warm in a 37&#176;C waterbath before use</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:261px;">Penicillin-Streptomycin (10,000 U/mL)</td>
			<td style="width:179px;">ThermoFisher</td>
			<td align="right" style="width:119px;">15140163</td>
			<td>Warm in a 37&#176;C waterbath before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Trypsin-EDTA (0.25%)</td>
			<td style="width:179px;">ThermoFisher</td>
			<td align="right" style="width:119px;">25200056</td>
			<td>Warm in a 37&#176;C waterbath before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">PBS, pH 7.4</td>
			<td style="width:179px;">ThermoFisher</td>
			<td align="right" style="width:119px;">10010049</td>
			<td>Warm in a 37&#176;C waterbath before use</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:261px;">KaryoMAX Colcemid Solution in PBS</td>
			<td style="width:179px;">ThermoFisher</td>
			<td align="right" style="width:119px;">15212012</td>
			<td>Warm in a 37&#176;C waterbath before use</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:261px;">KaryoMAX Potassium Chloride Solution</td>
			<td style="width:179px;">ThermoFisher</td>
			<td align="right" style="width:119px;">10575090</td>
			<td>Warm in a 37&#176;C waterbath before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Methanol (HPLC)</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">A452N1-19</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Acetic Acid, Glacial</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">BP1185-500</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:261px;">Decon Contrad 70 Liquid Detergent</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">04-355-1</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:261px;">Wright and Wright-Giemsa Stain Solutions</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">23-200733</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Permount Mounting Medium</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">SP15-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Axio Imager 2</td>
			<td style="width:179px;">Zeiss</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
	</tbody>
</table>

analysis of the ambient particulate matter-induced chromosomal aberrations using an in vitro system

Exposure to particulate matter (PM) is a major world health concern, which may damage various cellular components, including the nuclear genetic material. To assess the impact of PM on nuclear genetic integrity, structural chromosomal aberrations are scored in the metaphase spreads of mouse RAW264.7 macrophage cells. PM is collected from ambient air with a high volume total suspended particles sampler. The collected material is solubilized and filtered to retain the water-soluble, fine portion. The particles are characterized for chemical composition by nuclear magnetic resonance (NMR) spectroscopy. Different concentrations of particle suspension are added onto an in vitro culture of RAW264.7 mouse macrophages for a total exposure time of 72 hr, along with untreated control cells. At the end of exposure, the culture is treated with colcemid to arrest cells in metaphase. Cells are then harvested, treated with hypotonic solution, fixed in acetomethanol, dropped onto glass slides and finally stained with Giemsa solution. Slides are examined to assess the structural chromosomal aberrations (CAs) in metaphase spreads at 1,000X magnification using a bright-field microscope. 50 to 100 metaphase spread are scored for each treatment group. This technique is adapted for the detection of structural chromosomal aberrations (CAs), such as chromatid-type breaks, chromatid-type exchanges, acentric fragments, dicentric and ring chromosomes, double minutes, endoreduplication, and Robertsonian translocations in vitro after exposure to PM. It is a powerful method to associate a well-established cytogenetic endpoint to epigenetic alterations.

Great care should be taken in choosing the location of the TSP sampler, as well as the time of the year when collection is performed. The chemical composition as well as the size of particles may substantially influence the results. The material collected should be visible against the white filter. A normal mouse metaphase spread will have 40 acentric chromosomes. The goal of the technique is to demonstrate a change (or absence thereof) in the proportion of abnormal chromosomes in treated...

Watch this Scientific Journal Video about Analysis of the Ambient Particulate Matter-induced Chromosomal Aberrations Using an In Vitro System at JoVE.com

Analysis of the Ambient Particulate Matter-induced Chromosomal Aberrations Using an In Vitro System

This protocol describes techniques for the quantification and characterization of chromosomal aberrations in vitro in RAW264.7 mouse macrophages after treatment with ambient air particulate matter.

Analysis of the Ambient Particulate Matter-induced Chromosomal Aberrations Using an In Vitro System

Exposure to particulate matter (PM) is a major world health concern, which may damage various cellular components, including the nuclear genetic material. ...

The overall goal of this experiment, is to detect chromosomal damage induced by exposure of cells to particulate matter, extracted from ambient air. This method can help answer one key question in the field of particulate matter, and that is does particulate matter exposure induce chromosomal damage? The main advantage of this technique, is it allows direct visualization of the damage induced in the genetic material.After collecting and analyzing particles according to the text protocol, carry out particle exposure by warming complete growth medium, 0.25%trypsin, and PBS in a water bath at 37 degrees celsius, for at least 30 minutes before culture initiation. After washing raw 264.7 cells, add one milliliter of the warm trypsin solution to the dish and dislodge the cells from the bottom of the tissue culture vessel by scraping. Then collect the cells and make a single-cell suspension by repeated pipetting.With trypan blue, count the number of cells, then use pre-warmed complete medium to plate them at a density of 8000 per square centimeter in a 100 millimeter tissue culture dish. Then use complete medium to adjust the volume to 10 milliliters for a final concentration of 50, 000 cells per milliliter. Incubate the cells at 37 degrees celsius, and 5%CO2 for 24 hours to allow them to attach.In a bio-safety cabinet, use sterile PBS to dilute filtered particles at a concentration of 0.5 milligrams per milliliter, for a 5 microgram per milliliter treatment dose, and at 5 milligrams per milliliter, for a 50 microgram per milliliter treatment dose. To treat cells with particulate matter, check the cultured cells under a microscope with 10x magnification for cell growth, cell morphology, culture condition, and contamination. The cells should be at least 30%confluent at this stage.Using a sterile pipette, aseptically aspirate the medium and use two milliliters of 37 degrees celsius PBS to wash the culture vessel two times. Add a pre-determined dose of particulate matter with fresh medium and incubate the cultures at 37 degrees celsius and 5%CO2 to parallel the exposure used for concurrent genotoxic and epigenotoxic analysis. To arrest cells at metaphase, after washing the cells add two milliliters of pre-warmed medium with five microliters per milliliter of colcemid solution to the culture, and incubate at 37 degrees celsius and 5%CO2 for two hours.After the incubation, completely remove the medium and use warm PBS to wash the cells two times. Then add trypsin solution and incubate the cultures at 37 degrees celsius for one minute. Using a cell scraper, detach the cells and add 10 milliliters of PBS to inactivate the trypsin.Then pipette the cells up and down at least ten times to create a single-cell suspension, and transfer the cells into a 15 milliliter, conical centrifuge tube. Place the tubes in a swing out centrifuge, and spin the cell suspension at 400 times g and room temperature for five minutes. To carry out hypotonic treatment, remove the supernatant from the tubes without disturbing the cell pellet, and leave approximately 0.5 milliliters of PBS.Gently break the cell pellet and use a P200 pipette to make a single cell suspension. Then add four milliliters of pre-warmed potassium chloride solution drop wise with gentle shaking. Incubate the cell suspension in a 37 degree celsius water bath for 20 minutes.After the hypotonic treatment, fix the cells by adding an equal volume of fixative to the tube, and gently mix by inverting the tube. Centrifuge the tubes at 400 times g at room temperature for five minutes and remove the supernatant. This stage, the cell pellet will have increased in size and become whitish in color and more visible.Remove the supernatant. Add four milliliters of fresh fixative, and incubate the tubes at room temperature for 30 minutes. Then centrifuge the tubes, remove the supernatant, and use four milliliters of fixative to wash the cells two more times.Immerse glass slides completely in 10%liquid detergent for 30 minutes. Then rinse the slides thoroughly in cold running tap water for 30 minutes. Use distilled water to rinse the slides three times to completely remove the detergent.Then immerse them in distilled water, and store the slides in the refrigerator overnight. Drop ten microliters of cell suspension on a chilled wet slide, and allow it to dry overnight at room temperature. To stain and mount the samples, prepare 50 milliters of giemsa staining solution by mixing one part of giemsa stain solution, with one part of PBS, and pour into a coplin jar.Immerse the slides in staining solution for 20 minutes, then rinse the slides in distilled water to remove excess stain, and immediately use a hair dryer to dry the slides. Leave the slides at room temperature overnight. The following morning, apply a single drop of mounting medium on the slide.Gently place a cover slip on top, and allow the mounting medium to slowly spread over the slide. Then use a paper towel to remove excess medium. Finally, use a bright field microscope at 100x magnification to examine the structural chromosomal aberrations in the metaphase spreads.This image shows that a normal mouse metaphase spread, will have 40 acentric chromosomes. Treatment with particulate matter induces various chromosomal aberrations, such as a chromatid break, an acentric fragment, a ring chromosome, a dicentric chromosome, double minutes, a Robertsonian translocation, and an endoreduplication. While attempting this procedure, it is important to remember that only proliferating cells should be used.Following this procedure, other methods, like M-FISH and SKY, can be used to answer additional questions. Like whether inter-chromosomal, stable aberrations are present. Don't forget the cautions and carcinogens, and precautions such as wearing gloves, should always be taking while performing this procedure.

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8.6K vistas.  University of Arkansas for Medical Sciences. The overall goal of this experiment, is to detect chromosomal damage induced by exposure of cells to particulate matter, extracted from ambient air. This method can help answer one key question in the field of particulate matter, and that is does particulate matter exposure induce chromosomal damage? The main advantage of this technique, is it allows direct visualization of the damage induced in the genetic material.After collecting and analyzing particles according to the text protoco...