660 likes | 680 Views
Pathology. &Immunology. a bird’s eye view. 11 th August 2011. RSBS slides by Jeremy/Deepa Cat photos by Sheng Yi. what’s inside. 0. what is pathology? 1. allergens 2. common pathologies 3. uncommon pathologies 4. incurable pathologies c. The next step. PART I. pa·thol·o·gy
E N D
Pathology &Immunology a bird’s eye view 11th August 2011 RSBS slides by Jeremy/Deepa Cat photos by Sheng Yi
what’s inside 0. what is pathology? 1. allergens 2. common pathologies 3. uncommon pathologies 4. incurable pathologies c. The next step
PART I. pa·thol·o·gy the study and diagnosis of disease
Affected areas: Metabolic/specific body systems e.g. cardiovascular system Problems: Excess/Lack of a particular substance, Gain-of-function/Loss-of-function
According to the College Board… “ A patient is rushed to the emergency room after fainting on the street. He regains consciousness and complains of severe stomach pain. Because there are many possible reasons for this pain, a pathologist must step in to help solve the mystery.
According to the College Board… The pathologist will analyze the patient’s blood and look for abnormalities. If surgery is necessary, he or she will also examine tissue samples. The pathologist's tests and conclusions will help the medical team identify the cause of the patient’s pain. Once they’ve found the cause, they can begin treatment. ”
Example: Blood donation Criteria: Iron level in blood >= 12g/dl Many healthy people (especially females) who want to donate blood are turned away because of “low iron levels”
which leads us to this school of thought: anti-psychiatry • The specific definitions of, or criteria for, hundreds of current psychiatric diagnoses or disorders are vague and arbitrary, leaving too much room for opinions and interpretations to meet basic scientific standards. • Prevailing psychiatric treatments are ultimately far more damaging than helpful to patients.
Subjective If people survive with such “low” baseline levels, where’s the harm? Ye olde drop of blood in CuSO4 (aq) – Test for anemia
Another headache in defining the pathological state: DSM-IV Compared to a “naturalist’s field guide to birds” Mental illness not easy to define. The DSM-IV tends to present a list of symptoms, not diseases/disorders (disease = medical condition with specific signs + symptoms)
The WRONG diagnosis… case study: Scoliosis a medical condition in which a person's spine is curved from side to side
“ schooliosis After preventive activity in school or college, it can lead to incorrect diagnosis of scoliosis that triggers a series of unnecessary medical interventions on adolescents. There can be diagnostic and therapeutic cascades involving several specialists, which can end with iatrogenic* damage on a healthy child with normal back. The risks are unnecessary overexposure to X-rays (repeated x-ray diagnostic), rehabilitation techniques with side effects (traction), stigmatizing orthopaedic treatment (braces for back injury) and time costs, travel, etc. * inadvertent adverse effects or complications caused by or resulting from medical treatment or advice. ”
Worse: Disease mongering is a pejorative term for the practice of widening the diagnostic boundaries of illnesses, and promoting public awareness of such, in order to expand the markets for those who sell and deliver treatments, which may include pharmaceutical companies, physicians, and other professional or consumer organizations. Examples include male pattern baldness. Disease mongering
Worst: Marxists such as Vicente Navarro (1980), and others, linked medicalisation to an oppressive capitalist society. They argued that medicine can disguise the underlying causes of disease, such as social inequality and poverty, and instead people see health as an individual problem. Others examined the power and prestige of the medical profession, including use of terminology to mystify and of professional rules to exclude or subordinate others. Medicalisation
Marxists such as Vicente Navarro (1980), and others, linked medicalization to an oppressive capitalist society. They argued that medicine can disguise the underlying causes of disease, such as social inequality and poverty, and instead people see health as an individual problem. Others examined the power and prestige of the medical profession, including use of terminology to mystify and of professional rules to exclude or subordinate others. We’re here to break things down for you
Key Message Even scientists have trouble agreeing on what is pathological
PART II. Overview of Immunology
Acquired Immunity for Humans • Important Terms: -Leukocytes (Phagocytic WBCs- e.g. Macrophages) - Lymphocytes (T-Cells /B-Cells)
How the Immune system works • Lymph circulates the body and microbes are collected in spleen/lymph nodes where they are digested by resident macrophages • Leukocytes recognise and ingest molecules of pathogens using receptors on cell surface • Macrophages activate Lymphocytes using cytokines
The Lymphocytes… • Each T-Cell or B-Cell has many receptor proteins that bind to and particular foreign molecule • The receptors on any single T-Cell/B-Cell are the SAME • But there are millions of different leukocytes
How the Immune system works • Activated Lymphocytes undergo cellular division • B-cells can bind to free intact antigens/antigens on surface of proteins • T-cells bind to surface antigen fragments (Note: There are both Helper T-Cells and Cytotoxic T-Cells)
PART III. Allergies
atishoo example cat allergy What is it caused by? How is it caused?
Allegy caused by a certain protein secreted by the cat: Fel d 1 The protein is of an unknown function to the animal but causes an IgG or IgE reaction in sensitive humans (either as an allergic or asthmatic response).
And this Fel d 1 an example of an allegern which is an allergen // antigen triggers the production of an antibody by the immune system, which will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader.
Video on Allergies: http://www.youtube.com/watch?v=nudFAzJsTog
And one example of an antihistamine is: Chlorpheniramine which is similar to Doxepin Used to treat dermatological itch, sleep maintenance
And both of them bind to the: Histamine H1 receptor Note the structural similarity
THINK FAST Pop quiz: which amino acid is histamine derived from? Glycine Histidine Isoleucine Lysine Leucine Methionine Asparagine Pyrrolysine Proline Glutamine Arginine Serine Threonine Selenocystein Valine Tryptophan Tyrosine Alanine Cysteine Aspartic acid Glutamic acid Phenylalanine
Histidine histamine Histidine decarboxylase
Then what’s with… Epinephrine / Adrenaline for allergy control?
Allergic reactions vasodilation, mucous secretion, nerve stimulation, and smooth muscle contraction Can worsen to: Anaphylactic shock : anaphylaxis associated with systemic vasodilation that results in low blood pressure. It is also associated with severe bronchoconstriction to the point where the individual is unable to breathe. Adrenaline increases heart rate, constricts blood vessels, dilates air passages
THINK FAST What is the most common allergen responsible for anaphylactic shock in S’pore? peanuts pollen
Of those people who actually experience anaphylaxis, up to 1% may die as a result. Anaphylaxis has been estimated in one study to account for approximately 1,500 deaths per year in the U.S. In the United Kingdom, mortality rates for anaphylaxis have been reported as up to 0.05 per 100,000 population, or around 10-20 a year.
Fascinating skin allergies: Aquagenic urticaria (“allergy” to water) not a true histamine releasing allergic reaction
Fascinating skin allergies: Dermatographic urticaria The symptoms are thought to be caused by mast cells in the surface of the skin releasing histamines without the presence of antigens, due to the presence of a weak membrane surrounding the mast cells (store histamine). The histamines released cause the skin to swell in the affected areas.
http://popgloss.com/art/efb7a41308bc4dc26052d17ace570a40&pageoffset=48http://popgloss.com/art/efb7a41308bc4dc26052d17ace570a40&pageoffset=48
Key Message Allergens are pervasive but (usually) easily managed
PART IV. The incurables HIV.Huntington’s disease. Cancer.Lupus. Prions
HIV-AIDS Human Immunodeficiency Virus-Acquired Immunodeficiency Syndrome
Testing and Confirmation of the Disease • Includes testing for the virus itself as well as low white blood cell count • Since virus may remain dormant, the symptoms (compromised immunity) may not appear until years later
Why so tricky to treat? • Viral coat proteins mutate rapidly • The host immune system produces antibodies and T-lymphocytes against the original strain of viral coat proteins • Hence the body has no defence against newly mutated strains which have different coat proteins
HIV and the immune system: http://www.youtube.com/watch?v=eOCKOcbr0Os&feature=related HIV – 90 day video: http://www.youtube.com/watch?v=IExRHL7D_NI&feature=related