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Not Everything Dies: Blood






Blood has always been an inevitable and crucial physical evidence. It made forensic science a revolutionary field of study. Furthermore it is omnipresent in all violent crimes. Blood is a vector which indicates the sequence of events in a crime and match the suspect to the crime scene. The DNA typing has got a significant impact on violent criminal investigations.

What is blood?
It is a body fluid in humans and other animals. It is composed of blood cells suspended in blood plasma which constitutes 55% of blood fluid, mostly water (92% by volume), it delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes), white blood cells (also called WBCs or leukocytes) and platelets (also called thrombocytes). The most abundant cells in vertebrate blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates oxygen transport by reversibly binding to this respiratory gas and greatly increasing its solubility in blood. In contrast, carbon dioxide is mostly transported extracellularly as bicarbonate ion transported in plasma. Vertebrate blood is bright red when its hemoglobin is oxygenated and dark red when it is deoxygenated. Some animals, such as crustaceans and mollusks, use  to carry oxygen, instead of hemoglobin. Insects  and some mollusks use a fluid called hemolophyl instead of blood, the difference being that hemolymph is not contained in a closed circulatory system. In most insects, this "blood" does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their tracheal system to suffice for supplying oxygen. Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Arthropods, using hemolymph as part of their immune system.  Blood is circulated around the body through blood vessels by the pumping action of the heart. In animals with lungs, arterial blood carries oxygen from inhaled air to the tissues of the body, and venous blood carries carbon dioxide, a waste product of metabolism produced by cells, from the tissues to the lungs to be exhaled. Medical terms related to blood often begin with hemo- or hemato- (also spelled haemo- and haemato-) from the Greek word αἷμα (haima) for "blood". In terms of anatomy and histology, blood is considered a specialized form of connective tissue, given its origin in the bones and the presence of potential molecular fibers in the form of fibrinogen.



  
Bear in mind any testing procedures concerning blood and other biological fluids make them potential vectors of  blood-borne diseases such as [1]hepatitis, [2]tuberculosis and [3]AIDS.
There are however some measures of precaution which are applied worldwide and which are presented below to illustrate how important it is to follow all of them. Barrier protection  should be used at all times to protect skin and mucous membrane from contamination with blood, body fluids containing visible blood or other body fluids. Examples of barrier protection include disposable lab coats, gloves, eye and face protection. Any person who works with blood and blood products  should receive hepatitis vaccination just as a precaution, namely, the vaccination itself does not protect You from being infected. The consequences of accidents can be disastrous. Communicable diseases are serious threat for the workers and their families.

Blood has got its chemical function, its flow and bloodstain pattern – this last one is important at the crime scene. The shape and distribution of blood drops can assist in reconstructing how the crime was committed. The blood stain pattern consists of the following factors:
-          spots of blood shows the failing drop that produced them, they help to estimate their velocity and impact angle and the distance fallen from the source;
-          the diameter of a blood spot estimates the distance the drop has fallen after the first five or six feet, beyond this distance the change is too slight/ small to be reliable and taken into account;
-          the edge characteristics of blood spots  has got absolutely no meaning unless the effect of the target surface is well – known, what will matter is a distance from the scallops around the edge;
-          the degree of spatter is characterized by a single blood drop which depends far more upon the smoothness of the target surface than the distance the drop falls. For example a blotter causes a drop to spatter to a considerable extent at a distance if 18-20 inches whereas falling from 100 feet it will leave no trace of itself when falls on glass or smooth surfaces. Just remember the smaller the diameter of the drops is, the higher velocity of the impact that produced them;
-          directionality of a small bloodstain is easily determined provided the difference between an independent spatter and a castoff or satellite thrown from a larger drop is recognized and acknowledged;
-          the character of a bloodstains  made by drops, smaller droplets or larger quantities of blood may reveal movement of initial staining or determined if the body or any blood traces were re-positioned or moved from the original position;

“Blood is a very uniform material from the standpoint of aerodynamics and presents ability to reproduce specific patterns which are not affected by any significant degree by age or gender; bear in mind that atmospheric temperature, pressure, humidity have no measurable effect on its behavior”

Some of the chemicals to screen blood are carcinogenic or cancer causing, if it happens it goes in contact with a skin it has to be immediately removed and rinsed. Each of the bloodstains and blood drops has to described and cataloged; from their form, color, size, position, direction of splash, height of fall. The best way to preserve it is to take a photography. A scale should be included for the close – up photographs. Remember of all types of evidence found at the crime scene the blood is the most fragile. Biological evidence such as blood, semen, saliva, does deteriorate with time; drying or freezing the samples of specimens slows down this deterioration. Blood typing  eliminates suspects or discriminates them, it is match a match process and has to be done at all times.

Blood tests and blood typing does have a goal, forensic biology evolves and enhances its field of study. Biotechnology is thriving and without a cloud of doubt it will continue to develop in foreseeable future.




[1]    It is  inflammation of the liver tissue. Some people have no symptoms whereas others develop yellow discoloration of the skin and whites of the eyes, poor appetite, vomiting, tiredness, abdominal pain, or diarrhea. There are five main types of viral hepatitis: type A, B, C, D and E. Hepatitis A and E are mainly spread by contaminated food and water. Hepatitis B is mainly sexually transmitted, but may also be passed from mother to baby during pregnancy or childbirth. Both hepatitis B and hepatitis C are commonly spread through infected blood such as may occur during needle sharing by intravenous drug users. Hepatitis D can only infect people already infected with hepatitis B.
[2] (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis .  Most infections do not      have symptoms, in which case it is known as latent tuberculosis. About 10% of latent infections progress to active disease which, if left untreated, kills about half of those infected. The classic symptoms of active TB are a chronic cough with blood-containing sputum, fever, night sweats, and weight loss.
[3] Human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). As the infection progresses, it interferes more with the immune system, increasing the risk of common infections like tuberculosis, as well as other opportunistic infections, and tumors that rarely affect people who have working immune systems. These late symptoms of infection are referred to as AIDS and is often also associated with weight loss.    HIV is spread primarily by unprotected sex (including anal and oral sex), contaminated blood transfusions, hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding. 

Bibliography:

1.      Criminal Investigations – Crime Scene Investigation.2000
2.      Forensic Science.2006
3.      Techniques of Crime Scene Investigation.2012
4.      Forensics Pathology.2001
5.      Pathology.2005  
6.       „A Short History of the Polymerase Chain Reaction". PCR Protocols. Methods in Molecular Biology.
7.      Molecular Cloning: A Laboratory Manual (3rd ed.). Cold Spring Harbor,N.Y.: Cold Spring Harbor Laboratory Press.2001
8.      "Antibodies as Thermolabile Switches: High Temperature Triggering for the Polymerase Chain Reaction". Bio/Technology.1994
9.       "Thermostable DNA Polymerases for a Wide Spectrum of Applications: Comparison of a Robust Hybrid TopoTaq to other enzymes". In Kieleczawa J. DNA Sequencing II: Optimizing Preparation and Cleanup. Jones and Bartlett. 2006
10.   "Microscale chaotic advection enables robust convective DNA replication.". Analytical Chemistry. 2013
11.  Human Physiology. An Integrate. 2016

Acknowledgements: 
The Police Department; 
https://www.politie.nl/mijnbuurt/politiebureaus/05/burgwallen.html and a Chief Inspector – Mr. Erik Akerboom                                               ©

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