Biology_Blood

Question 2 Part B The 2 blood products I have chosen are platelets and plasma Platelets Platelets are small clear cell fragments about 2-3 µm in diameter. Platelets circulate in the blood of mammals and are involved in hemostasis and lead to the formation of blood clots. Platelets provide the necessary hormones and proteins for coagulation. Collagen is released when the lining of a blood vessel is damaged. The platelet recognizes collagen and begins to work on coagulating the blood by forming a kind of stopper, so further damage to the blood vessel is prevented. How platelets are produced' Platelets are either removed from collected units of whole and pooled to make a therapeutic dose or is collected from the process of apheresis. The pooled whole blood platelets also known as random platelets can be produced using two methods. A unit of whole blood is placed into a centrifuge and goes through the process of a “soft spin”. At these settings the platelets stay suspended in the plasma. The platelet rich plasma is then removed from the red blood cells. It is then centrifuged at a faster setting to collect the platelets from the plasma. In the second method, the unit of whole blood is centrifuged using settings that cause the platelets to become suspended in the “buffy coat layer”. This layer contains the platelets and white blood cells. The “buffy coat” is put in a sterile bag and then suspended in a small amount of red blood cells and plasma. It is then centrifuged again to separate the red and white blood cells from the platelets and plasma. In spite of the method used for preparation, the platelets can be combined into one container using a sterilized connection device to make a single product with the required dosage. |Whole Blood in collection Tube |Blood after Centrifugation |Buffy Coat and RBCs |Top View of buffy coat | |[pic] |[pic] |[pic] |[pic] | Figure 1 (http://www.ambion.com/techlib/append/supp/wbc.html) The specific situations in which they are used Platelets are used to help clot the blood and seal wounds in surgical and cancer patients. Leukaemia and chemotherapy treatments can reduce a patient’s platelet count. Chemotherapy helps save lives but it destroys healthy platelets at the same time. Without platelet transfusions, these patients could bleed to death. Patients suffering from leukaemia and other cancers of the blood are doubly affected. In addition to the effects of chemotherapy, their disease may crowd out or destroy the bone marrow cells that make healthy platelets. While disease or a genetic disorder can cause a lower number of platelets they can also be depleted because of a specific treatment or surgery. Burn victims, organ transplant patients, marrow transplant patients and those who have undergone heart surgery often require not only blood transfusions but platelet transfusions as well. Also Platelet Rich Plasma has been used in wound healing Plasma Blood plasma is the liquid component of blood, consisting of around 50% of the total blood volume. It is usually straw coloured, although it can be cloudy or greyish, depending on the health and diet of the plasma’s host. Plasma is made up of about 91% water, with the rest of the 9% being made up of proteins, minerals, waste products, clotting factors, hormones, and immunoglobins. Without plasma, blood cells would have no medium to travel on as they moved through the body. Plasma also performs a number of other useful functions in the body. How Plasma is produced' The whole blood is drawn from the patient and then placed in a centrifuge. As the blood spins, the heavier blood cells (i.e. red blood cells) settle to the bottom, and the plasma rises to the top. Tests can be performed on the plasma to learn more about the health of the donor, and the blood cells can also be analysed for information. See figure 1 for images of the process. The specific situations in which they are used Doctors sometimes use infusions of plasma to treat a variety of medical conditions. Pure plasma contains clotting factors which increase the rate at which blood clots, making it useful in surgery and in the treatment of hemophilia. Also plasma is use to treat Von Willebrand disease. It used in critical care settings for treatment of shock and burns, during surgery, and for fluid replacement therapy. Comparison of Platelets & Plasma to Whole Blood Platelets concentrates are used rather than whole blood because whole blood can be used to make a number of other blood products. Also there is less than 1% of the platelets in whole blood. Using whole blood rather than the blood products would be inefficient and the whole blood could be used for other things. The red and white blood cells may not be need in its current form when given to a patient that needs platelets or plasma. (Step 2: The components of blood. http://www.pennmedicine.org/health_info/bloodless/000209.html 23 Nov. 10) Question 3 Why is there a need for artificial alternatives to human blood' • Human blood has to be kept cool, and it only has a shelf life of 42 days. This makes it impractical for emergency crews to carry it in ambulances or for medical staff to carry it onto the battlefield. Also volume expanders alone may not be enough to keep a badly bleeding patient alive until they reach the hospital. • Doctors have to make sure that the blood is the right type (A, B, AB or O) before giving it to a patient. If a person receives the wrong type of blood, the patient could have a bad reaction and die. • The number of people who need blood is growing faster than the number of people who donate blood. • Viruses like HIV and hepatitis can contaminate the blood supply. • Artificial blood doesn't do all the work of real blood but instead, it carries oxygen in situations where a person's red blood cells can't do it on their own. • Unlike real blood can’t be sterilized to kill bacteria and viruses. • Doctors can also give it to patients regardless of blood type. • Blood has a short shelf life compared to artificial blood The general advantages of using artificial blood The general advantages of artificial blood are that it: ▪ Can compensate for intravascular volume insufficieny in hemorrhagic shock ▪ Can deliver oxygen to organs and tissues during almost complete blood exchange ▪ Chemical modifications of Heomoglobin based oxygen carriers (HBOC) are able to reduce the side-effects such as the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels (vasoconstriction) from the HBOC. ▪ Is relatively safe to use ▪ Is compatible in the human body ▪ Is able to transport and release oxygen where needed ▪ Is storable and durable for longer time periods ▪ Is free of pathogens and toxins which would produce an immune system response in the human body ▪ would reduce the need for donors. The general disadvantages of using artificial blood The general disadvantages of using artificial blood are that: ❖ The patients’ immune system may sometimes react negatively to the foreign blood that is inserted into the body ❖ For trauma/shock patients it can become challenging to understand which types of blood substitutes have affected which problem in the patient’s body ❖ There is currently no working source of artificial blood exists that can perform the diverse tasks of real human blood cells ❖ Social questions may arise over the use of an artificial substance internally i.e. is it moral or ethical to use artificial blood' Comparison of 2 main types of artificial blood–Modified haemoglobin & perfluorocarbons Haemoglobin based oxygen carriers (HBOCs) Haemoglobin-based Oxygen Carriers were created as a mechanism to mimic the oxygen-carrying role of haemoglobin in the body, while still reducing the need for real human haemoglobin. |Advantages |Disadvantages | |1 Available in much larger quantities. |1 reduced circulation half-life. | |2 Can be stored for long durations. |2 disrupts certain physiological structures, especially the | |3 Can be administered rapidly without typing or cross-matching |gastrointestinal tract and normal red blood cell haemoglobin. | |blood types. |3 the release of free radicals into the body. | |4 Can be sterilized via pasteurization. | | HBOCs vaguely resemble blood. They are very dark red and are made from real, sterilized haemoglobin, which can come from a variety of sources: • RBCs from real, expired human blood • RBCs from cow blood • Genetically modified bacteria that can produce haemoglobin • Human placentas HBOCs work like ordinary RBCs. The molecules of the HBOC float in the blood plasma, picking up oxygen from the lungs and dropping it off in the capillaries. The molecules are much smaller than RBCs, so they can fit into spaces that RBCs cannot, such as into extremely swollen tissue or abnormal blood vessels around cancerous tumors. Most HBOCs stay in a person's blood for about a day. This is a lot less than the 100 days or so that ordinary RBCs circulate. However, HBOCs also have a few side effects. The modified haemoglobin molecules can fit into very small spaces between cells and bond to nitric oxide, which is important to maintaining blood pressure. This can cause a patient's blood pressure to rise to dangerous levels. HBOCs can also cause abdominal discomfort and cramping that is most likely due to the release of free radicals, harmful molecules that can damage cells. Some HBOCs can cause a temporary, reddish discoloration of the eyes or flushed skin. Perflurocarbons (PFCs) Unlike HBOCs, PFCs are usually white and are entirely synthetic. They're a lot like hydrocarbons but they contain fluorine instead of carbon. PFCs are chemically inert, but are good at carrying dissolved gasses. They can carry between 20-30% more gas than water or blood plasma. For this reason, doctors primarily use PFCs in conjunction with supplemental oxygen. PFCs are oily and slippery, so they have to be emulsified to be used in the blood. Usually, PFCs are mixed with other substances frequently used in intravenous drugs, such as lecithin or albumin. These emulsifiers eventually break down as they circulate from the blood. The liver and kidneys remove them from the blood, and the lungs exhale the PFCs the way they would carbon dioxide. PFCs, like HBOCs, are extremely small and can fit into spaces that are inaccessible to RBCs. For this reason, some hospitals have studied whether PFCs can treat traumatic brain injury by delivering oxygen through swollen brain tissue. |Advantages |Disadvantages | |1 PFCs do not react with oxygen. |1 often causes flu-like symptoms. | |2 PFCs allow easy transportation of the oxygen to the body. |2 unable to remain mixed as aqueous solutions | |3 they allow increased solubility of oxygen in plasma. |3 a decrease in blood platelet count. | |4 PFCs minimize the effects of factors like pH and temperature |4 PFC products cannot be used by the human body, and must be | |in blood circulation. |discarded. | |5 Extremely low toxicity |5 This takes approximately 18-24 months. | |6 High degree of thermal & chemical stability |6 because PFCs absorb oxygen passively, patients must breathe | |7 Due to their non polarity, they have excellent compatibility |at a linear rate to ensure oxygenation of tissues. | |with almost any substrate | | [pic] Assessment of the effectiveness of artificial blood I believe that the artificial blood is fairly effective. Without these blood substitutes a lot of people would be affected. Artificial blood may not replace blood but it still has its uses and if fully utilised can help patients with various diseases and illnesses. Artificial blood can keep people long enough to be saved. It also helps to reduce the burden on blood banks and the relatively low in supply donated blood. Also as seen in the advantage/disadvantage tables above there are mores advantages for artificial blood than disadvantages. Bibliography Q2 Part B 2010 Australian Red Cross Blood Service http://www.donateblood.com.au/all-about-blood/how-donated-blood-used 23 Nov. 10 Blood Index 2007 Blood Products http://www.bloodindex.com/Blood_Products.php 23 Nov. 10 Platelet 23 November 2010 at 09:25. http://en.wikipedia.org/wiki/Platelet 23 Nov. 2010 Blood products Created: 30/4/2006 Updated: 29/11/2009 http://www.frca.co.uk/article.aspx'articleid=100093 23 Nov. 2010 Written by S.E. Smith Edited by O. Wallace Last Modified: 12 November 2010. What is Blood Plasma' http://www.wisegeek.com/what-is-blood-plasma.htm 23 Nov. 10 Written by Tricia Ellis-Christensen. Edited by Niki Foster. Last Modified: 19 November 2010. What are Platelets' http://www.wisegeek.com/what-are-platelets.htm 23 Nov. 10 Clinic, BHR. BHR Clinic Brussels Belgium Platelet Rich Plasma Testing:International Hair Transplant Specialists FUE/FUT & Body Hair [Internet]. Version 12. Knol. 2009 Aug 14. Available from: http://knol.google.com/k/bhr-clinic/bhr-clinic-brussels-belgium-platelet/3drmtg0ilqcoj/10. 23 Nov. 10 2010 CSL Behring Uses of Plasma http://www.cslplasma.com/plasma/plasma-uses.htm 23 Nov. 10 Q3 Wilson, Tracy V..  "How Artificial Blood Works"  29 December 2006.  HowStuffWorks.com.  22 November 2010. Bruce J. Leone, M. D. December, Jacksonville Medicine. 1998. Artificial Blood: What Is It' Will I Use It' http://www.dcmsonline.org/jax-medicine/1998journals/december98/artificialblood.htm 22 Nov. 10 Zac Canders ELE 482: Biomedical Seminar III. March 28 2005. Artificial Blood: Polymerized Human Hemoglobin http://www.ele.uri.edu/Courses/ele482/S05/Zac_2.pdf 22 Nov. 10 By Anjali Thakkar COSMOS 2007 Cluster 1 Mentor: Professor Paul Feldstein Artificial Blood http://cosmos.ucdavis.edu/archives/2007/cluster1/thakkar_anjali.pdf 22 Nov. 10 Synthetic Blood to the Rescue. http://csat.au.af.mil/2025/concepts/800105.HTM 23 Nov. 10