Question 1

Anabolic agent steroids (AAS) compounds are used in sports because

Accepted Answer

Anabolic agent steroids (AAS) promote development of male characteristics, such as increased muscle mass, strength, and aggression. While they may indirectly improve oxygen capacity through increased muscle mass, they do not increase red blood cell count or provide long-term enhancement of adrenaline capacity.

Question 2

Which of the following substances are not endogenous?

Accepted Answer

All the substances listed (EPO, testosterone, estrogen, and GHB) are endogenous, meaning they are naturally produced within the body.

Question 3

What is physiological pH?

Accepted Answer

Physiological pH refers to the pH range at which normal biological functions occur in living organisms, which is typically between 7.35-7.45. Choice C of 7.4 falls within this range. Choices A, B, and D are all outside of the usual physiological pH range.

Question 4

The central blood collected at autopsy comes from the

Accepted Answer

The answer of The central blood collected at autopsy comes...

Question 5

The femoral artery/vein is the place that ________ blood is collected at autopsy

Accepted Answer

The femoral artery/vein is a central location for blood collection at autopsy, as it is located in the middle of the body and is a major blood vessel that carries blood to and from the heart. Peripheral blood vessels would not be as reliable for blood collection, and redistributed or separated blood would not accurately reflect the body's original blood distribution.

Question 6

Which body fluids are considered filtrates of the blood?

Accepted Answer

Oral fluid (saliva) and urine are both considered filtrates of the blood. Saliva is produced by the salivary glands, which filter blood to produce saliva. Urine is produced by the kidneys, which filter waste and excess substances from the blood.

Question 7

Which of these fluids is considered to be anatomically isolated?

Accepted Answer

Vitreous fluid is the clear gel-like substance that fills the large chamber at the back of the eye called the vitreous chamber. It is anatomically isolated because it is contained within the eye and does not freely communicate with other body fluids. Oral fluid, bile, and urine are all secreted by organs that are connected to other body systems and have the potential to mix with other fluids or be influenced by them.

Question 8

Why is vitreous fluid considered to be valuable as a matrix in post-mortem testing?

Accepted Answer

Vitreous fluid is considered valuable as a matrix in post-mortem testing because concentrations of drugs and metabolites are preserved longer than in other tissues. This is due to the fact that vitreous fluid is a closed system that is less affected by post-mortem changes and diffusion limitations.

Question 9

An analyst collects hair from a victim of a drug faciliated sexual assault. After cleaning, they cut it into 0.5cm segments and analyze these segments and find flunitrazepam at measurable concentrations. When the data is plotted as drug concentration on the y-axis and concentration on the x-axis, the points form a roughly linear pattern sloping downward. The indicates that

Accepted Answer

The linear pattern sloping downward indicates that the concentration of the drug is decreasing over time. This suggests that the dose was relatively recent, rather than several days or weeks in the past.

Question 10

A weakly basic drug with a pKa of 7.5 partitions from the blood into OF with a pH of 6.7. If ion trapping occurs, where will the drug be trapped?

Accepted Answer

The drug with a pKa of 7.5 exists primarily in its unionized form in blood at physiological pH (neutral to slightly acidic). When it partitions into OF with a lower pH of 6.7, it will become more ionized and therefore trapped in its ionized form. Since OF has a lower pH than blood, the drug will likely be trapped in the more ionized form in the oral fluid. Therefore, choice B is correct.

Question 11

Phenytoin is a weakly acidic drug with a pKa of 8.3. Assume that the urine has a pH of 6.2. To what degree will phenytoin be ion trapped in the urine?

Accepted Answer

The answer of Phenytoin is a weakly acidic drug with...

Question 12

The novel basic drug methcathinone has a pKa of 8. OF is collected from a driver stopped for possible DUI and is tested in a forensic toxicology laboratory. Assuming the blood is at physiological pH and the OF has a pH of 6.5, the concentration detected in the OF is likely to be _________ than the plasma concentration.

Accepted Answer

Methcathinone has a pKa of 8, which means it is a weak base that will be mostly ionized at physiological pH (~7.4). When the pH is lowered to 6.5 in the OF sample, more of the drug will be in the lipid-soluble, non-ionized state, making it more easily detectable. This means that the concentration of methcathinone detected in the OF is likely to be higher than the plasma concentration.

Question 13

What type of reactions are utilized in immunoassay tests?

Accepted Answer

Immunoassay tests rely on the specificity of antigen-antibody reactions to detect and quantify analytes in a sample. Other types of reactions such as acid-base or oxidation-reduction are not typically used in immunoassay tests. While enzymes are often used as detection labels in immunoassays, the reactions involved are primarily antigen-antibody interactions.

Question 14

Immunoassays are used for what purpose in forensic toxicology?

Accepted Answer

Immunoassays are commonly used in forensic toxicology laboratories to perform initial screening of biological specimens for selected drug classes, such as opioids, benzodiazepines, and amphetamines. They are not typically used for identification of new psychoactive substances (NPSs) or new variants of opioids, and are not accurate for precise quantification of drugs.

Question 15

The units of blood alcohol are typically given in

Accepted Answer

Blood alcohol levels are typically given in grams per deciliter (g/dL) in the United States.

Question 16

The limits established for BAC are set by

Accepted Answer

The limits for BAC (Blood Alcohol Concentration) are set by legislation. This legislation varies between countries, states, and provinces. These limits are put in place to ensure public safety and prevent drunk driving. Law enforcement enforces these limits through administering breathalyzer tests and prosecuting those who exceed them. Public health services and local data may provide information regarding the effects of alcohol consumption, but they do not establish legal limits for BAC.

Question 17

In phase 1 metabolism, ethanol is converted to acetaldehyde by what enzyme?

Accepted Answer

Ethanol is primarily metabolized by alcohol dehydrogenase (ADH) in phase 1 metabolism, which converts ethanol into acetaldehyde.

Question 18

Why does ethanol elimination follow zero-order kinetics?

Accepted Answer

Ethanol elimination follows zero-order kinetics because the enzymes responsible for metabolizing ethanol, primarily alcohol dehydrogenase in the liver, become saturated at relatively low ethanol concentrations. This saturation means that the rate of ethanol metabolism is constant over time, regardless of the concentration of ethanol in the bloodstream, until those concentrations fall below a level where the enzymes are no longer saturated.

Question 19

The descriptor rho used in blood alcohol calculations is the same as the

Accepted Answer

The answer of The descriptor rho used in blood alcohol...

Question 20

A man downs two shots (1.5 fluid ounces each) of a liquor that is listed as 72 proof. The density of ethanol is 0.88 ounces per fluid ounce and one ounce is 28.35 grams. How many grams of ethanol did he ingest?

Accepted Answer

Proof is twice the alcohol by volume (ABV) percentage, so 72 proof means 36% ABV. Each shot is 1.5 fluid ounces, so two shots are 3 fluid ounces. The volume of ethanol is 36% of 3 fluid ounces, which is 1.08 fluid ounces. The density of ethanol is 0.88 ounces per fluid ounce, so the weight of ethanol is 1.08 * 0.88 = 0.9504 ounces. Converting to grams: 0.9504 ounces * 28.35 grams/ounce = 26.94 grams, approximately 27 grams.

Quiz 9: Applications of Forensic Toxicology