Headline Here Sub Headline Here

MICROSCOPY

TYPES OF MICROSCOPES LIGHT MICROSCOPES Compound

TYPES OF MICROSCOPES LIGHT MICROSCOPES Dissecting (Stereo) Drosophila melanogaster

TYPES OF MICROSCOPES LIGHT MICROSCOPES Fluorescence

TYPES OF MICROSCOPES LIGHT MICROSCOPES Phase-contrast

TYPES OF MICROSCOPES LIGHT MICROSCOPES Compound Dissecting (Stereo) Fluorescence Phase-contrast Inverted

TYPES OF MICROSCOPES ELECTRON MICROSCOPES Transmission A transmission electron microscope image of a thin section cut through an area of mammalian lung tissue. This high magnification image shows a mitochondrion. Image courtesy of Wikiipedia

TYPES OF MICROSCOPES ELECTRON MICROSCOPES Scanning Flea

CONCEPTS Magnification - the ratio of the apparent size of the object compared to its real size

CONCEPTS Resolution - ability to distinguish fine detail

CONCEPTS Working distance - distance between the specimen and the lens

CONCEPTS Depth of field - depth of focus

EXAMINATION OF BIOLOGICAL MATERIAL

HAIR ANALYSIS

No two hairs are identical in structure – therefore it cannot be said that a hair from a crime scene that looks like hair from the suspect definitely came from the suspect based on microscopic examination. Only when part of the follicle is still attached to the root and DNA can be obtained and matched can you say for sure which individual the hair came from.

Hair examples: a. Human head hair (450x) b. Dog fur (450x) c. Deer hair (100x) a. Human head hair (450x magnification) b. Dog fur (450x) c. Deer hair (100x) d. Rabbit fur (450x) e. Cat fur (450x) f. Mouse hair (450x)

Hair examples: d. Rabbit fur (450x) e. Cat fur (450x) f. Mouse hair (450x)

Diameter of the medulla Medullary Index = Diameter of the medulla Diameter of the hair Human hairs have a medullary index of less than 1/3 while the medullary index of animal hair is 1/2 or greater.

SOIL ANALYSIS

What is soil? Earth material that has been collected accidentally or on purpose and is related to investigation. Definition will depend on whom you ask. Farmer – top 6-12 inches of the earth’s crust where plants grow Geologist – organic and mineral matter composing the earth Forensic geologist consider soil as earth material that has been collected accidentally or on purpose and is related to the matter being investigated.

What is soil made of? Minerals Plants Animal matter Synthetic products: Glass, paint, asphalt, cement, etc.

How do we test the soil? Macroscopic examination Microscopic examination Chemical properties Physical properties

URINALYSIS Doesn’t give direct evidence but can be used to build a case

Specific gravity Specific gravity of a liquid is a comparison of that liquids mass to the mass of an equal volume of water at the same temperature. A liquid’s specific gravity depends on the components of that liquid. For example, adding salt to water increases its specific gravity. In adult humans normal specific gravity of urine ranges from 1.001 to 1.030. An increase in specific gravity (ie, an increase in concentration of solutes in the urine) can result from conditions such as dehydration.

Specific gravity Refroactometer - Page 34 of Prac book

Specific gravity Page 35 of Prac book

Specific gravity pH Do students know what pH is??? The pH of urine can vary between 4.6 and 8, with neutral (7) being norm. In persons with hyperuricosuria, acidic urine can contribute to the formation of stones of uric acid in the kidneys, ureters, or bladder.[11] A diet high in citrus, vegetables, or dairy can increase urine pH (more basic)[dubious – discuss]. Some drugs also can increase urine pH, including acetazolamide, potassium citrate, and sodium bicarbonate.[citation needed] A diet high in meat can decrease urine pH (more acidic).[citation needed]

Specific gravity pH Presence of glucose In cases of diabetes, urine may contain glucose because the cells of diabetics cannot utilise all of the glucose in the blood. Therefore, extra glucose accumulates in the bloodstream and is removed by the urinary system.

Specific gravity pH Presence of glucose Presence of protein Proteins are not normally found in urine, but can be detected if the kidneys are not functioning properly.

POWDER IDENTIFICATION In the case of determining the identity of an unknown substance, crime lab experts must use testing procedures that give characteristic results. These tests and their results must be established prior to the examination of the unknown substance. Once the tests are verified, they are recorded and used repeatedly to prove the identity of suspect substances. For example, if you want to determine if an unknown white powder is cocaine, you must have a previously established positive test for cocaine. Then you can conduct this established test on an unknown white powder. It is also important to perform more than one positive test on an unknown. Proper identification requires that you use enough different tests to rule out the possibility that the unknown may be any other substance. For example, a lab technician may be testing an unknown white powder to determine whether or not it is cocaine. To be thorough, the technician will run a series of tests on the powder. If all tests are positive for cocaine then the technician feels certain that the results are correct. The forensic scientist in the crime lab must carefully perform each test on the unknown. Then test results must be precisely recorded. The results they gather must be so exact that the identification in correct beyond any reasonable doubt.

BLOOD

WHAT IS BLOOD?

PLASMA v SERUM Clotted blood – no fibrinogen = SERUM Unclotted blood – fibrinogen = PLASMA EDTA = di-sodium salt of Ethylene-diamine-tetra-acetic acid

FLUID Distributes important components around the body – nutrients, hormones, waste products

FORMED ELEMENTS Red cells White cells Platelets

Red Blood Cells - Erythrocytes

HAEMOGLOBIN Four globular protein subunits - 2 alpha (); 2 beta (β) chains Heme group - ferrous ion of iron (Fe2+) Transports - Oxygen from the lungs Carbon dioxide to the lungs

White Blood Cells - Leucocytes Phagocytes Neutrophils Immunocytes Lymphocytes

Neutrophils 10-15 µm

Small Lymphocyte 10-12 µm

Large Lymphocytes 12-16 µm

Platelets - Thrombocytes

The Blood Group Systems

What is blood made up of?                        An adult human has about 4–6 liters of blood circulating in the body. Blood consists of several types of cells floating around in a fluid called plasma. The red blood cells (RBCs) contain haemoglobin, a protein that binds oxygen. RBCs transport oxygen to, and remove carbon dioxide from the tissues. The white blood cells fight infection. The platelets help the blood to clot, if you get a wound for example. The plasma contains salts and various kinds of proteins.  

What are the different blood groups? Blood Groups, Blood Typing and Blood Transfusions The discovery of blood groups                       Experiments with blood transfusions, the transfer of blood or blood components into a person's blood stream, have been carried out for hundreds of years. Many patients have died and it was not until 1901, when the Austrian Karl Landsteiner discovered human blood groups, that blood transfusions became safer. Mixing blood from two individuals can lead to blood clumping or agglutination. The clumped red cells can crack and cause toxic reactions. This can have fatal consequences. Karl Landsteiner discovered that blood clumping was an immunological reaction which occurs when the receiver of a blood transfusion has antibodies against the donor blood cells. Karl Landsteiner's work made it possible to determine blood types and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930.                                                                                               Blood group 0 If you belong to the blood group 0 (null), you have neither A or B antigens on the surface of your red blood cells but you have both A and B antibodies in your blood plasma. What are the different blood groups? The differences in human blood are due to the presence or absence of certain protein molecules called antigens and antibodies. The antigens are located on the surface of the RBCs and the antibodies are in the blood plasma. Individuals have different types and combinations of these molecules.   The blood group you belong to depends on what you have inherited from your parents.

What are the different blood groups? There are more than 20 genetically determined blood group systems known today The AB0 and Rhesus (Rh) systems are the most important ones used for blood transfusions. Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals.

ABO blood grouping system According to the ABO blood typing system there are four different kinds of blood types: A, B, AB or O  

               Blood group A If you belong to the blood group A, you have A antigens on the surface of your RBCs and B antibodies in your blood plasma.   Blood group B If you belong to the blood group B, you have B antigens on the surface of your RBCs and A antibodies in your blood plasma. AB0 blood grouping system

Blood Groups, Blood Typing and Blood Transfusions Blood group AB The discovery of blood groups                       Experiments with blood transfusions, the transfer of blood or blood components into a person's blood stream, have been carried out for hundreds of years. Many patients have died and it was not until 1901, when the Austrian Karl Landsteiner discovered human blood groups, that blood transfusions became safer. Mixing blood from two individuals can lead to blood clumping or agglutination. The clumped red cells can crack and cause toxic reactions. This can have fatal consequences. Karl Landsteiner discovered that blood clumping was an immunological reaction which occurs when the receiver of a blood transfusion has antibodies against the donor blood cells. Karl Landsteiner's work made it possible to determine blood types and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930.   What is blood made up of?                        An adult human has about 4–6 liters of blood circulating in the body. Among other things, blood transports oxygen to various parts of the body. Blood consists of several types of cells floating around in a fluid called plasma. The red blood cells contain hemoglobin, a protein that binds oxygen. Red blood cells transport oxygen to, and remove carbon dioxide from, the body tissues. The white blood cells fight infection. The platelets help the blood to clot, if you get a wound for example. The plasma contains salts and various kinds of proteins. What are the different blood groups?                                                       The differences in human blood are due to the presence or absence of certain protein molecules called antigens and antibodies. The antigens are located on the surface of the red blood cells and the antibodies are in the blood plasma. Individuals have different types and combinations of these molecules. The blood group you belong to depends on what you have inherited from your parents. There are more than 20 genetically determined blood group systems known today, but the AB0 and Rh systems are the most important ones used for blood transfusions. Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous or individuals. Nobel Laureate Karl Landsteiner was involved in the discovery of both the AB0 and Rh blood groups. AB0 blood grouping system                Blood group AB If you belong to the blood group AB, you have both A and B antigens on the surface of your RBCs and no A or B antibodies at all in your blood plasma. Blood group O If you belong to the blood group O (null), you have neither A or B antigens on the surface of your RBCs but you have both A and B antibodies in your blood plasma.

The ABO blood groups The most important in assuring a safe blood transfusion. The table shows the four ABO phenotypes ("blood groups") present in the human population and the genotypes that give rise to them. Blood Group Antigens on RBCs Antibodies in Serum A Anti-B B Anti-A AB A and B Neither O Anti-A and anti-B

Giving someone blood from the wrong ABO group could be fatal. Why group A blood must never be given to a group B person?                                                                                                                                                                                                  Giving someone blood from the wrong ABO group could be fatal. The anti-A antibodies in group B attack group A cells and vice versa. Blood group O negative is a different story.

The Rhesus (Rh) System Well, it gets more complicated here, because there's another antigen to be considered - the Rh antigen. Some of us have it, some of us don't. If it is present, the blood is RhD positive, if not it's RhD negative. So, for example, some people in group A will have it, and will therefore be classed as A+ (or A positive). While the ones that don't, are A- (or A negative). And so it goes for groups B, AB and O.

The Rhesus (Rh) System (Cont.) They are named for the rhesus monkey in which they were first discovered. RBCs that are "Rh positive" express the antigen designated D. 85% of the population is RhD positive, the other 15% of the population is running around with RhD negative blood.

Do you know which blood group you belong to? According to above blood grouping systems, you can belong to either of following 8 blood groups: Do you know which blood group you belong to?

                                                                            A person with Rh- blood can develop Rh antibodies in the blood plasma if he or she receives blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies. A person with Rh+ blood can receive blood from a person with Rh- blood without any problems.

Why is an Rh incompatibility so dangerous when ABO incompatibility is not during pregnancy? Most anti-A or anti-B antibodies are of the IgM class (large molecules) and these do not cross the placenta. In fact, an Rh−/type O mother carrying an Rh+/type A, B, or AB foetus is resistant to sensitisation to the Rh antigen. Her anti-A and anti-B antibodies destroy any foetal cells that enter her blood before they can elicit anti-Rh antibodies in her.

Rh incompatibility during pregnancy (cont.) This phenomenon has led to an effective preventive measure to avoid Rh sensitisation. Shortly after each birth of an Rh+ baby, the mother is given an injection of anti-Rh antibodies (or Rhogam). These passively acquired antibodies destroy any foetal cells that got into her circulation before they can elicit an active immune response in her.

Several methods for testing the ABO group of an individual exist Several methods for testing the ABO group of an individual exist. The most common method is: Serology: This is a direct detection of the ABO antigens. It is the main method used in blood transfusion centres and hospital blood banks. This form of testing involves two components: a) Antibodies that are specific at detecting a particular ABO antigen on RBCs.           b) Cells that are of a known ABO group that are agglutinated by the naturally occurring antibodies in the person's serum.

Illustration of the forward and reverse grouping reaction patterns of the ABO groups using a blood group tile http://www.bh.rmit.edu.au/mls/subjects/abo/resources/genetics1.htm

Blood transfusions – who can receive blood from whom?                  Blood transfusions – who can receive blood from whom? People with blood group O are called "universal donors" and people with blood group AB are called "universal receivers."

Play a game on Blood grouping for blood transfusion http://nobelprize.org/medicine/educational/landsteiner/index.html

MICROPIPETTING No Slides required