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Hematology What is Karl Landsteiner credited with discovering?

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1 Hematology What is Karl Landsteiner credited with discovering?

2 Blood Composition

3 Key Terms Anticoagulant: an agent that prevents the clotting of blood. –Examples are EDTA, Citrate and Heparin Capillary: small blood vessel that connects arterioles and venules Hematoma: a subcutaneous mass of blood at a venipuncture site

4 Key Terms Hemoglobin: the oxygen carrying molecule of red blood cells Hemolysis: the breakdown of red blood cells, with the release of hemoglobin into the plasma or serum. Cannot use hemolyzed samples in lab tests Icteric: jaundiced; dark yellow or greenish serum or plasma

5 Key Terms Lipemic: having abnormally high level of fat. Milky looking samples Plasma: pale yellow part of whole blood; contains all clotting factors Serum: liquid portion of blood without the protein fibrinogen, which is one of the clotting factors; clot removed

6 Key Terms Agglutination: the clumping together of rbc by the action of an antibody –When A cells are added to a blood sample, agglutination will occur only in the presence of anti-A Serology: the study of antigen – antibody reactions using laboratory tests

7 Function of Blood Transporting fluids such as: –Nutrients from digestive tract –O 2 from lungs –Waste from cells –Hormones Aids in heat distribution Regulates acid-base balance

8 Composition of Blood Plasma: liquid portion of blood w/out cells –Contains all of the following WaterNutrients ElectrolytesMetabolic waste product HormonesVitamins and enzymes Plasma proteins such as fibrinogen, albumin and globulin

9 Composition of Blood: Erythrocytes Red blood cells are responsible for: –Transport of oxygen and nutrients –Removal of waste and CO 2 from the cells –Distribution of heat Hemoglobin: the O 2 carrying potential

10 Composition of Blood: Leukocytes WBC are responsible for: –Phagocytosis – to engulf and absorb waste material and harmful microorganisms in the blood stream and tissues –Synthesis of antibody molecules –Inflammation process –Production of heparin – component found in lung and liver tissue which have the ability to prevent clotting of blood. Heparin used in the treatment of thrombosis

11 Cell Morphology Lymphocyte Segmented Neutrophil Platelet rbc

12 Composition of Blood: Leukocytes Types of Leukocytes –Granulocytes Neutrophils Eosinophils Basophils –Agranulocytes Lymphocytes Monocytes

13 Composition of Blood: Thrombocytes Platelets – the smallest of the solid components of the blood Responsible for the clotting process Coagulation: term for clotting Embolism: a blood clot which is moving through the body

14 Forensic Characterization of Blood 1 st questions a criminalist has to answer is: –Is it blood –If yes, is it human –If yes, can it be associated w/ a particular person Preliminary color test for blood is the Benzidine color test but this is carcinogenic so phenolphthalein is used and is known as the Kastle-Meyer Color test

15 Forensic Characterization of Blood Hemoglobin possesses peroxidase like activity which when mixed with phenolphthalein and hydrogen peroxide it will cause the formation of a deep pink color Kastle-Meyer is not specific for blood as some vegetables such as potatoes and horseradish contain peroxidase and can react; however they should not be common at a crime scene so it is often considered a good indicator

16 Forensic Characterization of Blood Hemastix strips can also be used to detect the presence of blood Luminol test is another presumptive test for blood which produces light rather than a color reaction. Objects being tested must be in a dark location to view the luminescence (emission of light). –Extremely sensitive and can detect blood diluted up to 300,000 times –Luminol will not interfere with other DNA testing

17 Forensic Characterization of Blood Once blood is found it must be determined to be human –Precipitin test is the standard test –Reagents are available to determine if blood is dog, cat or deer –A positive test is a cloudy ring or band at the point where the two liquids meet –Only a small amount of sample is required –Precipitin test is very sensitive and can test positive on a sample as old as 10 years –Extracted tissue samples from mummies as old as 4,000 years have tested positive

18 Forensic Characterization of Blood Gel diffusion is another method which can be used. Antigen and antibody assay Gel electrophoresis can also be used to determine if a sample is human blood or not Antigen and antibody assay Uses electrical current and ppt. line forms where the two samples meet if it is a positive reaction

19 Blood Types Four Major Groups –ABABO Blood types are inherited from your parents Antigen is present on the red blood cell; typing is done w/rbc Antibody is present in the plasma; antibody screening done on plasma

20 Blood Types O negative –Universal donor –It carries no antigen AB positive –Universal recipient –It carries no antibodies in the plasma 43% of population are O, 42% A, 12% B and 3% AB

21 Rh Factor (D antigen): found on the surface of rbc Rhesus factor: discovered in rhesus monkeys in 1937 Can be phenotypically positive or negative Positive is dominant over negative –If positive is present, then you will express positive phenotype _ _ + +

22 Blood Types: ABO Controlled by GENETICS!!!!! Two Categories –ABO and Rh AAAO OO A O A O AAAB BB ABBO AOOO A O B O A B A B

23 Blood Types: What Ag do they have? A positive blood has which Ag present on rbc? –A antigen and Rh antigen B negative blood has which Ag present on rbc? –B antigen AB + blood type has which Ag present? –Both A and B Ag and Rh antigen on the rbc

24 Who can donate to whom? A + donor: what blood types can this pt. receive? –A+, A-, O+, O- Your blood type is B-, what blood types can donate to you? –B- and O- AB- as a last resort

25 ABO Blood Types

26 Agglutination Reactions

27 Anti-AAnti- BAnti-A & Anti B AYesNoYes BNoYes ABYes ONo

28 Examples of ABO blood typing O negative carries no Ag and therefore does not react with any Anti A, B, AB Neg reaction Pos reaction

29 Anti- Rh Rh + YES Rh -NO Rh Antigen and Antibody Interaction

30 Normal Ranges RBC: female x10 6 mm 3 male x10 6 mm 3 WBC: x10 3 mm 3 (African Americans is sltly lower 3.2 is still normal) HCT: female 36-48% male 42-52% Hgb: female g/dL male g/dL Platelets : x10 3 mm 3

31 Blood Cell Maturation

32 Blood Splatter Analysis Location, distribution, and appearance of blood stains are an important part of forensics Investigators try to determine: –Direction –Dropping distance –Angle of impact Splatter analysis is often used for crime scene reconstruction

33 Blood Splatter Analysis Factors which influence stain patterns are: –Surface texture –Direction of travel Pointed end of bloodstain always faces its direction of travel –Angle of impact is determined by measuring the degree of circular distortion of the stain Blood striking a surface at right angles gives rise to a nearly circular stain As the angle decreases, the stain becomes elongated in shape

34 DNA DeoxyriboNucleic Acid Found in the nucleus 46 chromosomes 25,000 genes Structure determined by Crick and Watson DNA fingerprinting by Alec Jeffreys

35 Structure of DNA A polymer made of repeating nucleotides Nucleotide consists of a deoxyribose sugar, a phosphate, and a nitrogen base (Adenine, Thymine, Cytosine, or Guanine) Double stranded, helical Complementary base pairing, A=T, G=C

36 DNA at Work DNA in nucleus is copied into a strand of RNA (transcription) RNA is read at the ribosome to make assemble amino acids into proteins (translation) Every 3 bases on DNA codes for a different amino acid

37 Replication of DNA Replication – the synthesis of new DNA from existing DNA in the nucleus DNA polymerase assembles new DNA strand and proof- reads it Replication occurs in nucleus prior to cell division

38 Polymerase Chain Reaction A technique for replication, or amplifying, a portion of DNA outside the cell Each cycle doubles the number of copies 1 1x10 7 in 30 cycles

39 DNA Typing with Tandem Repeats Region of chromosome that contains multiple copies of a core DNA sequence arranging in a repeating fashion between the coding regions (genes) Restriction Fragment Length Polymorphisms used enzymes to cut the DNA around these tandem repeat sites and then run them on a gel electrophoresis A Southern blot was then performed and radioactive probes were hybridized to help visualize the RFLPs

40 RFLPs

41 PCR PCR has the following advantages: 1. PCR can use shorter sequences 2. shorter pieces more stable 3. smaller amounts of DNA can be used (10 -9 gram)

42 Short Tandem Repeats (STRs) A region of a DNA molecule that contains short segments of 3-7 repeating base pairs. Generally less than 450 bp long Less degradation Can be PCR’d Can multiplex a large number of these STRs at once US uses 13 STRs for tests

43 Capillary electrophoresis Sex Identification by focusing on the amelogenin gene

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