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Flashcards do conjunto (47)
- 1What is the purpose of clinical biochemistry (1).To diagnose, monitor and provide treatment information for routine and pathological reasons
- 2Describe what a biomarker is and explain three characteristics of a good biomarker (2).A naturally occurring molecule produced by a disease that can be identified.
Not present in healthy individuals
Easy to assay
Structurally stable - 3Describe what a reference range is and how it is used (2).A set of values that indicate upper and lower limits of a test based on otherwise healthy people. Different reference ranges may be used for each gender e.g. men hb =138-172g/L and women hb=121-151g/L
- 4What are some of the limitations of using a single reference range for a biomarker (2).Can be overlaps between diseased and nondiseased states
Ranges can vary based on age, gender and ethnicity
Ranges can vary lab to lab - 5Describe technical, analytical and clinical validity of clinical biochemical tests (3).Technical – calibration of analysers, reagents
Accuracy: ability of test to produce the true value of analyte
Precision: low standard deviation, able to reproduce same result consistently
Analytical – assay, how can the analyte be measured
Specificity: only measures target analyte
Sensitivity: low limit of detection of analyte
Clinical – how well does the biomarker represent the disease
Specificity: only detects patients with particular disease
Sensitivity: low limit of detection of disease - 6Describe the function of the kidney in maintaining homeostasis (3).Regulation of plasma and extracellular fluid volume
Controls sodium and water balance
Removal of excess H+ - 7Describe Glomerular Filtration Rate as a test for kidney function. Why is creatinine a suitable endogenous substance for GFR test. Include a description of the benefits and limitations (3).GFR refers to the rate at which plasma is filtered into primary urine, it is suitable because it needs to be filtered at the glomerulus, is not reabsorbed and is stable in the plasma
Benefits – easy to measure
Limitation – influenced by age, gender and concentration increases as renal function declines - 8Explain why the patient’s urine appeared dark in the case study below (3).Heart damage indicated by CK and potassium -> muscular degeneration -> excess myoglobinuria causing the urine to be dark
Also dehydration caused by alcohol and heroin - 9Why did the same patient become hypocalcaemic and hyperphosphataemic? (1)Decreased calcium reabsorption from the kidneys
Decreased phosphate removal from the kidneys - 10Describe the sources of purines, their function, catabolism and excretion (2).Source: produced naturally from liver, also found in foods like shellfish and alcohol
Function: subunits of nucleic acids, synthesis of nucleotide cofactors
Catabolism: broken down in liver and converted to uric acid
Excretion: kidneys and GI tract - 11Describe the symptoms and causes of hyperuricaemia (2)Symptoms: haematuria, nausea, swollen joints
Causes: excess alcohol, underlying diseases (overproducing purine) - 12Comment on the clinical history and biochemical result of the following case study (3). On examination, the joint was found to be red, shiny, and very tender. He has a family history of gout. Serum analysis showed the following (reference range is given in brackets): Urate 0.56 mmol/L (0.1–0.42)Increased uric acid (urate) -> hyperuricaemia -> forms crystals in joints -> causing swollen joint in toe
- 13Based on the same case study describe how should the patient should be treated initially and then in the near future (3).The patient has gout.
Initial treatment: NSAIDs, increase water intake, diet change
Future: steroids or colchicine - 14Describe the distribution of sodium and potassium ions in the extra- and intra-cellular fluids (1).ECF: Sodium, chloride and bicarbonate
ICF: Potassium, magnesium, phosphate - 15Describe the modes of action of antidiuretic hormone (2).Increases water reabsorption in DCT and CD
- 16Describe the renin-angiotensin-aldosterone system (3).Prorenin -> cleaved to renin by juxtaglomerular cells -> from angiotensinogen forms angiotensin I by renin angiotensin I -> from angiotensin I forms angiotensin II by ACE -> aldosterone is regulated by angiotensin II
- 17Describe the syndrome of inappropriate antidiuretic hormone (SIADH) (2).Disorder of impaired water excretion due to the overproduction of ADH
- 18Explain the results of this case study (2). Sodium 200 mmol/L 135–145 Potassium >10 mmol/L 3.5–5.0Increased sodium and potassium could be due to dehydration or acute kidney disease
- 19Describe one muscle enzyme as a biomarker for cardiac function (1).Creatinine kinase
- 20What tests are used to diagnose acute myocardial infarction (2).Serum cardiac troponin (troponin C)
Electrocardiogram (ECG) - 21Describe the main differences in the symptoms of myocardial infarction (MI) in women and men (2).Women = jaw/neck/upper back pain, fatigue,
Men = chest pain, shortness of breath, radiating arm pain - 22Describe three ways to treat hyperlipidaemia (3)Lifestyle changes
Statins
Cholesterol absorption inhibitors - 23Based on the information presented below, would you be confident the women was having a MI after the first test, and does this change after the second (2). Explain your reasons.Due to the T wave inversion and increased troponin it seems likely that this is myocardial ischemia due to the failure of the graft
- 24Describe three main functions of the liver (2).Filtration – removing waste products from the blood
Synthesis – albumin, clotting factors, angiotensin
Glucose storage – removes excess glucose from the blood and stores glycogen - 25How is bile produced and what is its role (1).Produced: created by hepatocytes and modified by cholangiocytes and stored in gallbladder
Function: break down fats, carry waste away - 26Serum aminotransferases and bilirubin are common biomarkers for liver function. Describe the abnormalities these markers detect and what limitations these tests have (4)Test: liver inflammation (ALT and AST), cholestasis (bilirubin and ALP)
Limitations: abnormal values can be due to conditions not related to liver function, ALP is also found in bone - 27On the basis of the information provided below, what is the likely cause of jaundice (3).Increased bilirubin levels with normal liver enzymes may be caused by underlying illness such as Gilberts syndrome. Bilirubin levels increased with illness like the flu
- 28Describe the roles, distribution and regulation of calcium ions in the body (2Role: structural, neurotransmitter, muscle contraction
Distribution: free ionised (47%), protein bound (46%) and complexed (7%)
Regulation: dietary intake, regulation through bones and kidney, loss through urine and faeces - 29What roles do parathyroid hormone, calcitriol and calcitonin play in the regulation of calcium (2)PTH: reabsorption of bone and kidneys
Calcitriol: increases calcium in plasma
Calcitonin: decreases calcium in plasma - 30Describe two symptoms of hypercalcaemia and its management (3)Symptoms: frequent urination, nausea
Management: IV, calcitonin injection - 31Explain the results obtained in the following case study (3) Total calcium 3.70 mmol/L 2.20–2.60Absence of parathyroid gland = no PTH decrease calcium levels. Vitamin D therapy increase in total calcium levels because vitamin D increases serum calcium via calcitriol increasing calcium uptake via intestines
- 32Describe the structure and function of the thyroid gland (1)Structure: butterfly-like gland in the neck
Function: regulates metabolism, growth, temperature - 33What role does iodine play in the production of thyroid hormones T3 and T4 (1)Iodine is needed to produce thyroxine and triiodothyronine
- 34What effects do T3 and T4 have (1)Triiodothyronine (T3): active, formed by removal of one iodine by kidneys, stimulates peripheral nervous system
Thyroxine (T4): inactive, little effects - 35What are three of the symptoms and signs of hyperthyroidism (2)Increased appetite, rapid heartrate, heat intolerance
- 36Describe two methods for managing hyperthyroidism (2)Removal of thyroid gland or anti-thyroid medication
- 37Explain the results for the case study below (3) TSH < 0.1 mU/L 0.2–3.5 Free T4 < 5 pmol/L 9–23 Free T3 2.5 pmol/L 4.0–6.5Graves disease is caused by hyperthyroidism. Carbimazole is a medication to reduce thyroid hormones by inhibiting thyroid peroxidases blocking the catalysation of iodine and reducing the active form of thyroxine
- 38Describe the metabolic characteristics of tumours and cancers (2)Divide uncontrollably, invasion of other tissues
- 39Describe three main modes of cancer treatment (2)Surgery: to confirm the cancerous tissue has been excised
Chemotherapy: interferes with DNA replication and prevents cell division
Radiotherapy: use of x-rays to destroy cancerous cells - 40Describe the characteristics of an ideal tumour marker and give one example of a marker for a common cancer describing its advantages and limitations (2)Be undetectable in health
Produced by malignant tissue
Specific to the site of malignancy
Circulate in concentrations proportional to tumour mass - 41What type of tumour is most likely to give this pattern of results in the case study below (2)In this case testicular cancer was suspected due to the swelling. The raised AFP and normal HCG would indicate a non-seminomatous germ tumour of the testis.
- 42What is another cause of a raised AFP? (1)Liver cancer
- 43Describe the potential for individual treatments of cancer using molecular genetic techniques in combination with biochemistry (3)Cytogenetic techniques can provide information about genetic mutations e.g. gene translocations
Can provide information about treatment e.g. PML patients with a specific gene translocation respond to treatment with all-trans retinoic acid so treatment can be individualised
Predict the sensitivity to chemotherapeutic agents - 44Describe the genetic marker for Alzheimer’s disease (2)Apolipoprotein E (APOE) gene – makes a protein that carries cholesterol into bloodstream
- 45Describe the main pathological biomarkers for Alzheimer’s disease (3)Beta-amyloid 42 – amyloid plaques
Tau
Phospho-tau – tau tangles - 46How is Alzheimer’s disease diagnosed (3)CSF biomarkers – increased neurocortical amyloid, tau
Brain imaging – amyloid plaques
Blood tests – amyloid beta - 47How is Alzheimer’s disease managed currently (2)Behaviour management and cholinesterase inhibitors
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- university Clinical biochemistry FlashCards sobre Exam, criado por Jorja Bull em 13-11-2023.
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