Cell injury, apoptosis and death I Flashcards
what are the steps in diagnosing a patient
1) take clinical history and document symptoms
2) examine for clinical signs
3) perform investigations (eg lab test)
what are the 2 different types of diagnostic lab test
give examples of both
1) QUANTITATIVE measurement: interpreted in relationship to “normal” range
eg ELISA for serum insulin level test
2) SUBJECTIVE assessment: based on pathologist assessment
eg cervical epithelial cells on slide
whata re the aims of epidemiology
- provide aetiological clues to cause of disease
- plan preventative measures
- provision of adequate medical facilites
- population screening for early diagnosis
epidemiology establishes the ASSOCIATION between a risk factor and occurence NOT CAUSAL RELATIONSHIP
what is a prospective study
- subjects followed over time
- monitor risk factors
- determine their relative risk
what is a retrospective study
- looking back over a period of time
- PAST exposure to suspected aetiological factors examined
- odds ratio determined
what is a cross sectional study
- prevalence bwteen DIFFERENT POPULATIONS at a particular time
- for public health planning
- assess the association between risk factor and disease (limited though)
what is the purpose of an autopsy
- for legal/medical purpose
- determine cause of death
- collect evidence for prosecution
- info gained used for CLINICAL AUDIT, EDUCATION, MEDICAL RESEARCH
- diagnostic discrepancies are found in ~30% of cases
what is a clinical autopsy
it is non-medicolegal
- on patients who die in hospital with UNCLEAR DIAGNOSIS/ other reasons
who is the only type of person allowed to perform medico-legal autopsies
Home Office pathologists
what underpins cell injury
what are the 2 types
if a new challenge is too great, or for too long, cells may FAIL to MEET this demand and /show signs of injury, change/loss of function, change in morphology
Types: 1) reversible 2) irreversible
what happens to irreversibly injured cells
cell death
1) apoptosis
or
2) necrosis
what are the signs of reversible cell injury
- ER and mitochondrial swelling
- chromatin clumping
what are the 7 general causes of cell injury
give examples
1) oxygen deprivation (hypoxia, ischaemia)
2) physical agents (mechanical trauma, extreme temperature)
3) chemical agents and drugs (Cyanide, CO, alcohol)
4) infectious agents (viruses, bacteria)
5) immunological reactions (anaphylactic reaction to protein)
6) nutritional imbalances (vitamin deficiency, under/overnutrition)
7) genetic derangements (sickle cell anaemia)
what are the mechanisms of cell injury
complex and unknown in many cases
what is cellular response to injury/stimuli dependant on
type, severity and duration of injury
what is the consequence of injury dependant onn
the type, state and adaptability of the injured cells
cellular injury results from what
functional and biochemical abnormalities in one or several of essential cellular components
what is a free radical
chemical species with a single unpaired electron in outer orbit eg O2-
how are ROS generated in cells
- abs of radiant energy (UV/ X-ray)
- REDOX reactions
- transition metals donating or accepting free electrons during intracellular reactions
- nitric oxide (ONOO-)
how is LIPID PEROXIDATION OF MEMBRANES relevant to ROS induced cell injury
- DOUBLE BOND in UNSAT F.A of membran elipids are attacked by ROS causing oxidative damage
how is OXIDATIVE MODIFICAION OF PROTEINS relevant to ROS induced cell injury
-oxidation of amino acid residue side chains, formation ofprotein-protein cross-linkages (e.g., disulfide bonds), andoxidation of the protein backbone, resulting in protein fragmentation
how is DNA DAMAGE relevant to ROS induced cell injury
Reactions with thymine in nuclear and mitochondrial DNA produce single-stranded breaks in DNA
