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MAJ Kris Paolino, MDInfectious Disease Staff
Chief, Clinical Trials CenterWalter Reed Army Institute of Research
Disclaimer
The views expressed in this presentation are those of the speaker and do not reflect
the official policy of the Department of Army, Department of Defense, or U.S.
Government
MicroscopyTechnical field of using
microscopes to view samples and objects that cannot be seen with the unaided eye
We will be using light microscopy
Calculating the magnificationIdentify the magnification of the ocular lensIdentify the magnification of the objective
lens in useMultiply the two together
Example:Ocular lens = 10xObjective lens = 40xMagnification is 400x
Oil Immersion lensesOil immersion is a technique to increase
resolution of a microscope
Use of transparent immersion oils with an oil immersion objective lens
You will need oil to have adequate visualization of the malaria parasites on the high power objectivesThe lens will typically state “oil” on the side
Correct use of a light microscopeMake sure the scope is plugged in and turned on
Ensure you are starting at the LOWEST power objective
Mount your glass slide using the cover slips or slide holder
Adjust the light source using the diaphragmRule of thumb:
Low light intensity for lower magnification High light intensity for higher magnification
Correct use of a light microscopeAdjust the ocular lenses to your eyes as
appropriateTake off your glasses if you wear them
Again, starting at the lowest objective focus using the COARSE adjustment knobsThis is the last time you will use this knobSome would say to move the lens as close to the
slide as possible, and then adjust away
DISCLAIMER: Anyone who breaks a slide will automatically be
enrolled in our next malaria challenge trial
Correct use of a light microscopeFocus in on your target (i.e.
red blood cells) at the LOWEST power
Make sure what you want to look at is CENTERED
In the thin smear of the malaria slide you want to try to start at the “feathered edged” of the slideCells are more spread out
Correct use of a light microscopeFocus in on your slide by switching to the
next highest objective lens (it will “CLICK” into position)
Adjust illumination as necessary
Each time you switch up to the next highest objective, re-focus, and re-center in on the slide using the FINE adjustment knob ONLYi.e. DON’T BREAK THE SLIDE
Correct use of a light microscopeWhen you get to the high power objectives, you
will need to use a drop of immersion oil
For malaria diagnostics, you will use the 100x objective
To place the oil, rotate the objective lenses so they are out of the way, and place a single drop of oil directly on the slide
Slowly rotate the oil lens back over the slide so that the drop of oil touches the lens
Correct use of a light microscopeUsing the oil lens, focus on the slide using
the FINE adjustment knob only until the cells are in focus
When you are done, wipe the oil immersion lens and the slide with lens paper only
If you have a camera (smartphones included) try to take a photo of what you are seeingInclude magnification in the teleconsultation
Keep your scope cleanUSE LENS PAPER TO WIPE THE OCULAR
AND OBJECTIVE LENSES AS NECESSARY
DON’T USE OIL ON LOWER POWER OBJECTIVE LENSES
DON’T TOUCH THE LENSES WITH YOUR FINGERS
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eutrophil
osinophil
Basophile
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