Urine And Diagnosis

Question 1

how did people used to try and diagnose disease?

Answer 1

using urine - looking at the colour, the smell, and even the taste of it.

Question 2

what does urine contain?

Answer 2

• water
• urea
• mineral salts
• breakdown products of a range of chemicals.

Question 3

how can urine diagnose diabetes?

Answer 3

presence of glucose in the urine.

Question 4

how can urine diagnose muscle damage?

Answer 4

large amounts of creatine will show up in urine.

Question 5

how long after conception does the human embryo implant into the uterus?

Answer 5

around 6 days after conception

Question 6

what chemical is produced at the site of the developing placenta?

Answer 6

human chorionic gonadotrophin (hCG)

Question 7

what was the most reliable pregnancy test until the 1960s?

Answer 7

injecting urine from a pregnant women into an African clawed toad. if the woman was pregnant the hCG present in her urine would trigger egg production in the toad within 8-12 hours of the injection.

Question 8

how do modern pregnancy tests work?

Answer 8

they test for hCG in the urine but they rely on monoclonal antibodies.

Question 9

what are monoclonal antibodies?

Answer 9

antibodies from a single clone of cells that are produced to target particular cells or chemicals in the body.

Question 10

how are monoclonal antibodies made?

Answer 10

1. mouse injected with hCG so it makes the appropriate antibody.
2. B-cells that make the required antibody are removed from the spleen of the mouse and fused with a myeloma.
3. the new fused cell is known as a hybridoma.
4. each hybridoma reproduces rapidly, resulting in a clone of millions of living factories making the desired antibody.
5. the monoclonal antibodies are collected, purified and then used in a variety of ways.

Question 11

what is a myeloma?

Answer 11

a type of cancer cell that divides very rapidly.

Question 12

what are the main stages of a pregnancy test?

Answer 12

1. the wick is soaked in the first urine passed in the morning.
2. the test contains mobile monoclonal antibodies that have very small coloured beads attached to them. they will only bind to the hCG.
3. the urine carries on along the test structure until it reaches a window.
4. at the window, there are immobilised monoclonal antibodies arranged in a line or pattern such as a positive + sign. which only bind to the hCG / antibody complex.
5. the urine continues up through the test to the second window.
6. at the second window there is usually a line of immobilised monoclonal antibodies that bind to mobile antibodies regardless of whether they are bound to hCG or not. this indicates that the test is working.

Question 13

why should women take pregnancy tests in the morning?

Answer 13

this is when they will have the highest levels of hCGs

Question 14

what happens to the test if a women is pregant?

Answer 14

the hCG in her urine binds to the mobile monoclonal antibodies and forms hCG / antibody complex (complete with a coloured bead) a coloured line or pattern will display in the first window.

Question 15

why is a line present in the second window of a pregnancy test?

Answer 15

to indicate that the test is working.

Question 16

who might take anabolic steroids?

Answer 16

athletes and body builders.

Question 17

what are anabolic steroids?

Answer 17

drugs that mimic the action of testosterone and they stimulate the growth of muscles.

Question 18

how can scientists determine whether an athlete has been using anabolic steroids?

Answer 18

anabolic steroids are excreted in urine. a urine sample can be tested using gas chromatography and mass spectrometry. this is done by vaporising the sample with a known solvent and passing it along a tube. the lining of the tube absorbs the gases and is analysed to give a chromatogram that can be read to show the presence of drugs.

Question 19

how is it possible to detect traces of drugs in the urine a while after the drug has been used?

Answer 19

drugs are filtered through the kidneys and stored in the bladder.

Question 20

how can urine be tested for drugs?

Answer 20

a urine sample is split into two. the first sample is tested by immunoassay using monoclonal antibodies to bind the drug to its breakdown product. the second sample is run through a mass spec to confirm the presence of a drug.

Question 21

how long does alcohol stay present in the urine?

Answer 21

6-24 hours

Question 22

how long does amphetamines stay present in the urine?

Answer 22

1-3 days

Question 23

how long does cannabis stay present in the urine?

Answer 23

22 hours to 30 days depending on use.

Question 24

how long does cocain stay present in the urine?

Answer 24

2-5 days.