Artificial Urine for Laboratory TestingAuthor(s): Brian R. ShmaefskySource: The American Biology Teacher, Vol. 52, No. 3 (Mar., 1990), pp. 170-172Published by: University of California Press on behalf of the National Association of Biology TeachersStable URL: http://www.jstor.org/stable/4449071 .

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Table 3. A Comparison of the Heart Rate of Male Subjects While Resting and Reading Aloud

Resting Reading t-value

N 5 5 Mean 66.8 79.8 4.65** SD 12.7 17.4

** = p> .01

reading aloud in public. The activity relates classic anatomy and physi- ology with human behavior. This kind of experience can be a potentially powerful motivator to enlighten and involve our students in the scientific enterprise and prepare them to func- tion better in the complex and dy- namic world of the 21st century (Kuhn 1987, 1988).

References Kuhn, D.J. (1988). Experiences in commu-

nity college science education: Restruc- turing the past and preparing for the fu- ture. College Student Journal, 22(3), 282-286.

Kuhn, D.J. (1987). Science education for the 21st century: A time for synthesis and new strategies. Tennessee Education, 17(l), 5-11.

How-

To-Do-It

Artificial Urine for Laboratory Testing

Brian R. Shmaefsky

The fear of contracting contagious microbial agents through body fluids has led to laboratory practices that limit exposure to blood, exudates, sa- liva and urine (Sharp & Smailes 1989). Due to the nature of the techniques and materials handled, clinical teaching laboratories require the ut- most protection for students. Students are inexperienced at handling haz- ardous substances and are at risk of being accidentally contaminated with potentially fatal pathogens: Hepatitis A and B, HIV and sexually trans- mitted bacteria (Ballman 1989). Elimi- nation of the clinical testing of body fluids from an anatomy and physi- ology curriculum is not recommended since students must be familiar with the psychomotor aspects of clinical testing before taking a job in the health sciences. Thus, body fluid sub- stitutes must be found that will permit students to have the necessary clinical experience while preventing their ac- cidental inoculation with a contagious disease.

Artificial blood and urine for use in standardizing clinical equipment is available from some specialty chem- ical companies, but these are generally too costly for the limited budgets of many high schools, undergraduate colleges and patient education pro- grams. Some biological supply compa- nies market bottles of crude artificial urine for eliciting normal and positive

Brian R. Shmaefsky is chair and assistant professor of biology at Northwestern Okla- homa State University, Alva, OK 73717. He has a B.S. in biology from Brooklyn College of the City University of New York and a M.S. in biology and Ed.D. in science edu- cation from Southern Illinois University. For the past three years he has researched and presented talks on the ethics of human genetic technology. Shmaefsky is an execu- tive officer in the Oklahoma Academy of Science and is a member of NABT, NSTA, the National Association of Science, Tech- nology and Society and an associate member of Sigma Xi.

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170 THE AMERICAN BIOLOGY TEACHER, VOLUME 52, NO. 3, MARCH 1990

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tests from simple urine assays. These products are clinically satisfactory for school use and are not very expensive. A major limitation is that the in- structor does not have control over the test result outcomes. A simple-to-pre- pare and inexpensive artificial blood has been devised for blood-typing in the classroom (Sharp & Smailes 1989). This allows students to safely practice performing simple chemical experi- ments on blood without the danger of contamination. The urinalysis labora- tory is equally important as blood- typing and could be safely conducted using instructor-prepared artificial urine. The artificial urine described in this article could be used to study various urine parameters using a urine hydrometer for specific gravity and urine test strips (dipstick) for the measure of glucose, ketones, pH and proteins. Procedures are included for test strip measures indicating the presence of abnormal urine param- eters, erythrocytes and leukocytes, if the instructor wishes to use these tests.

Methods & Materials

Normal human urine

The following reagents will be nec- essary for the preparation of normal human urine (Kark, et al. 1964):

Albumin powder (egg or bovine) Creatinine Distilled water Potassium chloride Sodium chloride Sodium phosphate (monobasic) Urea

A class of 30 students, working in groups of two, would require a class total of at least 1 liter of artificial urine for specific gravity and dipstick testing. The following instructions are for the preparation of approximately 2 liters of normal urine; half can be stored or used for abnormal urine studies.

To 1.5 liters of distilled water add 36.4 g of urea and mix until all the crystals are dissolved. Then add 15.0 g of sodium chloride, 9.0 g of potassium chloride and 9.6 g of sodium phos- phate; mix until the solution is clear. Check the pH with indicator paper or a pH meter to ensure the pH is within the 5 to 7 pH range for normal urine; if the solution is out of this pH range the pH may be lowered with IN hydro- chloric acid or raised with IN sodium hydroxide.

Next, place a urine hydrometer into the solution and dilute with water until the solution is within the specific

gravity range of 1.015 to 1.025. This solution will serve as the storage stock solution of "normal urine solution" and may be kept refrigerated for sev- eral weeks or frozen in plastic con- tainers for months. Before use, the stock solution should be warmed to room temperature. Then, to ensure a similarity to human urine, 4.0 g of cre- atinine and 100 mg of albumin may be slowly mixed into the 2 liters of the so-called normal urine solution.

Abnormal human urine

The artificial normal human urine may be modified to mimic several dis- eased or periodic conditions that are detectable in the urine. Abnormal urine is normally not available from student samples, thus students rarely experience the test results associated with disease. Also, the artificial ab- normal urine is an excellent medium to test student skills and observations with the clinical testing of urine. The following conditions may be exhibited by using the "normal urine solution" and additional inexpensive reagents.

1. Glycosuria: High levels of glu- cose due to diabetes mellitus, preg- nancy, excessive stress, renal tubular damage and brain damage. Add a minimum of 600 mg of glucose (dex- trose) to each liter of "normal urine solution" to obtain a minimally detect- able level of glycosuria. A moderate to high level of glycosuria can be achieved by adding 2.5 to 5.0 g of glu- cose to each liter of the solution. Su- crose or other sugars will not substi- tute for glucose; only glucose yields positive results with most urine test strips. Vitamin C (ascorbic acid) con- tamination of the urine, at values of 400 mg/l or greater, though, does yield false positive glucose results. This may add an interesting twist to the study of the accuracy and limitations of urinalysis.

2. Proteinuria: High levels of pro- tein in the urine is an excellent indi- cator of glomerular damage. In the ab- sence of glomerular damage, elevated urine protein may result from exces- sive exercise, cold exposure and acute abdominal diseases. Protein levels in excess of 300 mg of albumin per liter of "normal urine solution" will give positive results. Severe renal damage may be exemplified by adding 1 g of albumin to each liter of the urine solu- tion.

3. Ketonuria: Ketones of various types, which are normal liver metabo- lites, should not be found in detect- able amounts in the urine. Elevated ketone levels are indicative of cold ex-

posure, diabetes mellitus, dietary im- balances and genetically or chemically acquired metabolic abnormalities. Ke- tonuria may be exhibited by adding a minimum of 100 mg of acetoacetic acid or at least 1 ml of acetone to 1 liter of "normal urine solution."

4. Urine pH imbalances: Acidic urine can be obtained by adjusting the pH of the "normal urine solution" to a pH of 4.0 to 4.5 with 1N HCl. Consis- tent acidic urine is a sign of metabolic or respiratory acidosis, methanol poi- soning, or metabolic disorders (for ex- ample, phenylketonuria). Alkaline urine is obtained by adjusting the pH of the "normal urine solution" to a pH of 8 to 9 using 1N NaOH. Consistent alkaline urine is indicative of meta- bolic and respiratory alkalosis and uri- nary tract infections.

5. Hyposthenuria: Urine should have a specific gravity range of 1.015 to 1.025; some daily variation outside of this range is normal. Consistent production of dilute urine, with a spe- cific gravity less than 1.015, is an indi- cation of cardiovascular problems, diabetes insipidus, or renal tubule problems. The specific gravity of the "normal urine solution" may be low- ered by adding distilled water to a volume of the stock solution until the specific gravity approaches 1.005.

6. Hemoglobinuria: Hemoglobin in the urine result from excess levels of free hemoglobin in the blood due to excessive red blood cell lysis, renal damage, or the normal menstrual flow. Bovine (cow) hemoglobin is an inexpensive powdered reagent avail- able from many biological and chem- ical supply companies. Hemoglobin- uria can be exhibited by adding 260 mg of bovine hemoglobin to 1 liter of "normal urine solution." Hematuria, or the presence of whole blood in urine (a good indication of glomerular damage), may be modeled using hep- arinized or defibrinated sheep blood normally used in microbiological and cell cultures. The urine test strips are normally sensitive to 1 ml of whole blood in 1 liter of the urine solution.

7. Leukocyte presence: This is a dif- ficult test and requires the use of small amounts of reagent and urine. The presence of leukocytes in urine indi- cates urinary tract damage or infec- tion. The urine test strips can be faked into giving a positive leukocyte re- sponse by the addition of enzymes called esterases. Esterases are avail- able through biological, chemical and histological supply companies. Es- terase activity is measured in activity units; many companies sell the en- zymes by the unit or by units per mass. A positive test for leukocytes

TESTING 171

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may be achieved by adding 100 to 200 units of pork or rabbit liver esterase to 100 ml of the "normal urine solution." The leukocyte test must be performed immediately after the addition of the enzyme and may be performed on 10 ml samples in small test tubes.

A whole spectrum of urine abnor- malities could be included in one sample by mixing the appropriate amounts of the "abnormal conditions reagents" into a common 1 liter volume of the "normal urine solu- tion." For example, the urine from a patient with diabetes mellitus would have urine that tests positive for gly- cosuria and ketonuria, while a patient with glomerular damage would have urine that is positive for proteinuria, hemoglobinuria and hematuria.

The above method for the produc- tion of artificial urine is pragmatic for several reasons. It allows students to perform urinalysis without the fear of contamination by hazardous microor- ganisms. The procedure allows for the manipulation of the "urine" so stu- dents can encounter the diseased urine types not normally found among student urine samples. The materials for making the artificial urine are inexpensive and available from many biological and chemical supply companies. Lastly, the prepa- ration is simple, and large quantities may be stored for several months. The artificial urine is only accurate for use with urine test strips or related re- agents: it is not intended for use with electronic clinical analyzers.

Acknowledgments I would like to thank Mary Jo Shmaefsky

for her assistance with the formulation of the artificial urine chemistry. I would also like to thank Douglas Eder, who fostered my creativity in the teaching of biology.

References Ballman, G. (1989). Handling infectious

materials in the education setting. Amer- ican Clinical Laboratory, 8(7), 10-11.

Kark, R.M., Lawrence, J.R., Pollack, V.E., Pirani, C.L., Muehrcke, R.C. & Silva, H. (1964). A primer of urinalysis (2nd ed.). New York: Hoeber Medical Division, Harper & Row, Publishers.

Sharp, R.H., Sr. & Smailes, D.L. (1989). A simulation of the blood type test. The American Biology Teacher, 51(4), 232-233.

How-TIo-Do-It

Classroom Science for the Birds

Peter G. Weber Elizabeth R. Koon Suzanne P. Weber

Feeding birds helps make winter more enjoyable for many people living in the north. Overall, this aesthetic and recreational backyard activity is enjoyed by 15 to 25 percent of the households in major U.S. cities (Payne & DeGraaf 1975). In some communi- ties, 40 percent or more of the house- holds fill feeders (Ehrlich et al. 1988). About six million pounds of bird seed -the equivalent of a train of boxcars one mile long-is sold in the state of Maine alone (Cross 1973). Clearly, bird feeding is a popular and wide- spread backyard activity.

Winter bird feeding also has great potential for scientific study in the middle and high school life science classroom. Birds are fascinating, readily available living subjects. Studying birds is an excellent way to provide students with experiences in experimental design, data collection and analysis, as well as a rare oppor- tunity for genuine scientific problem solving in the classroom. Easily con- ducted studies that deal with such seemingly simple concepts as seed and feeding height preference quickly involve students in inductive and de- ductive reasoning processes as they grapple with the intricacies of behav- ioral ecology and the challenges of sci- entific research.

Some Background Information

Animal biologists have used bird feeders extensively to gain an under- standing of the individual behavior of birds. This research has concentrated on the kinds of attack and defense movements birds use as signals during agonistic (hostile) encounters. These behaviors- which occur both within and between different species -can easily be seen when birds come together to feed (e.g., Stokes 1962; Blurton-Jones 1968; Popp 1987). Studies have also focused on various factors that affect the social domi- nance between individual birds (e.g.,

Hamerstrom 1942; Sabine 1949; Mil- likan et al. 1985) and the social struc- ture within flocks (e.g., Ficken et al. 1981; Smith 1984). We have used bird feeders to investigate the winter home range of black-capped chickadees (Gannon & Weber 1985).

Feeders have also been used to study the foraging techniques, food preferences and niche differences of birds that eat seeds in winter (Hes- penheide 1966; Myton & Ficken 1967; MacArthur & MacArthur 1972; Davis et al. 1973; Geis 1980). Birds, like fish, live in a three-dimensional environ- ment. Consequently, they have evolved to use energy resources lo- cated at different heights. Field studies have shown that particular bird species prefer certain seed types and foraging heights (e.g., Smith 1967; Wilson 1970; Grubb 1975; Wil- liams & Batzli 1979). Differences in feeding height and food type are two of the several ways in which species have evolved to avoid competition through niche separation.

The feeding niche of a species in-

Peter G. Weber is a professor of biology at Piez Hall, State University of New York College at Oswego, Oswego, NY 13126. He has a B.A. from University of Wisconsin and a M.S. and Ph.D. from Michigan State University. He instructs a winter ecology course for SUNY Oswego in upstate New York. From 1985-89 Weber directed the Winter Science Curriculum Development Project, funded by the National Science Foundation. Elizabeth R. Koon is parent partner coordinator at Union Springs Cen- tral School, Union Springs, NY 13160. She has a B.A. from Denison University and a M.S. in secondary biology education from SUNY Oswego. Koon previously taught high school English and biology. Suzanne P. Weber is research scientist at SUNY Owego's Classroom Interaction Research Laboratory. She has a B.S. in biology from Michigan State University and a Ph.D. in ecology from Syracuse University. A certi- fied teacher who serves as an elementary science consultant to local school districts, Weber was editor of the Winter Science Curriculum Project from 1985-88.

172 THE AMERICAN BIOLOGY TEACHER, VOLUME 52, NO. 3, MARCH 1990

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