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General Use of Water In Research and Medicine
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In biological and chemical laboratories distilled water is the most often used form of water. Most often used to dilute aqueous solutions in order to get them to specific concentrations. Distilled water is also used in titrations. Distilled water is also used in preparing nutrient media most standard laboratory solutions fixatives and biological staining. |
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One popular biological stain is known is hematein. It is made by oxidizing an organic material that is extracted from logwood. When used ina distilled solution hematein can be used to differentiate cell nuclei from protoplasm for viewing using a microscope. The process involves using a fixed washed section of tissue then immersing it in a solution of hematein at a known strength. After a certain amount of time being immersed in the solution the tissue is removed and rinsed off to remove the excess stain. Then it is passed through a series of successive distilled water-ethyl alcohol baths gradually increasing the concentration of alcohol until the final bath is 100 percent alcohol. |
It is at this point that virtually all of the water has been removed from the tissue and replaces by the alcohol. The next step is to remove the alcohol and replace it with xylene. Xylene is a paraffin solvent. After a succession of melted paraffin baths at 50-60oC the paraffin displaces the xylene. After this step the tissue is embedded in a block of solid paraffin. This readies it for slicing with a microtome to the thickness of only a few microns. |
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Then using distilled water with small pools of albumin the paraffin embedded tissues samples are floated on the small pools of albumin in the water. Each one is about the diameter of a nickel and centered on a glass microscope slide then placed on the warm bed of a special hot plate. The heat causes the paraffin to flatten out and bond with the glass as the water evaporates. What is left behind is the albumin which now acts as a transparent adhesive or glue. |
Once the specimens in paraffin are firmly in place on the slides they are then placed on a rack and dipped in xylene to remove the paraffin. Upon completion of this step and the paraffin has been replaced by xylene each small thin section of tissue get a drop of Canada balsam and is covered by a paper thin cover glass. The slide is then baked for a day or two at 45o to 50oC. This process hardens the balsam and thus making the tissue ready for study. Before each use the slides can rinsed with distilled water to eliminate dust and water spots which impair viewing under a microscope. |
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Primer: Water Use In Research And Medicine
Water The Cleansing Agent
Water Use In Tissue Cell Culture
Water Usage In Pharmaceuticals
Pyrogens In Research And Medicine
Water Use In Blood Fractionation
Water Use In Cryobiology
General Use of Water in Research and Medicine
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