Cellules, protéines et enzymes du sang Flashcards
(16 cards)
β-TM or transfusion-dependent thalassemia is mainly due to:
a) Double heterozygosity β+mutation/β° mutation
b) Homozygosity for β° mutations
c) Homozygosity for β+mutations
d) Double heterozygosity β+/δβ°
e) β°/ααα genotype
B
Hb Bart fetal hydrops results from:
a) Point mutations of 3 α genes
b) Deletion of 2 α genes
c) Deletion of 4 α genes
d) Deletion of 3 α genes
e) Deletion of2 α genes/β°
C
Which of these definitions is more appropriate for TI?
a) A clinical definition that includes a wide spectrum of clinical thalassemia phenotypes
b) A definition for thalassemia phenotypes that are more severe than those of TM
c) A definition that includes any kind of thalassemia carrier
d) A definition for a combined genotype β+/β°
e) Transfusion-dependent thalassemia
A
In the physiological situation most Fe in the body:
a) Is stored as ferritin in the tissues
b) Is incorporated in heme of myoglobin
c) Is incorporated in heme of Hb
d) Is bound to the serum protein, transferrin
e) Is incorporated into enzymes
C
Which of the following statements on serum ferritin is correct:
a) Tissue ferritin differs from serum ferritin in that it is glycosylated
b) Serum ferritin contains mostly H-chains
c) Serum ferritin is Fe-rich
d) Serum ferritin reflects both reticuloendothelial and parenchymal Fe stores
e) In the presence of an elevated TSAT, patients tend to have higher serum ferritin for a given Fe burden
D
Which of the following statements on laboratory parameters in Fe disorders is correct?
a) Patients with ACD have increased TSAT percentages
b) Patients with IDA have low hepcidin levels and increased sTfR levels
c) Patients with Fe overload due to HFE-related hemochromatosis have normal plasma TSAT percentages and increased ferritin levels
d) Patients with ACD have decreased total body Fe stores
e) Patients presenting with Fe refractory Fe deficiency anemia due to a defect in TMPRSS6 have a normal TSAT and low ferritin levels
B
What best describes the physiological purpose of conjugating bilirubin with glucuronic acid?
a) To increase the molecular weight of bilirubin
b) To increase its reactivity for measurement
c) To increase the half life of bilirubin
d) To increase the solubility of bilirubin
e) To decrease the solubility of bilirubin
D
There are a number of inherited forms of hyperbilirubinemia. Which one is typically benign, with unconjugated bilirubin concentrations not exceeding 3 mg/dL (51 μmol/L)?
a) Crigler-Najjar syndrome,type I
b) Crigler-Najjar syndrome,type II
c) Dubin-Johnson syndrome
d) Gilbert’s syndrome
e) Rotor syndrome
D
The major difference between thalassemia and hemoglobinopathy is that:
a) in thalassemia the globin chains of hemoglobin are structurally altered.
b) in thalassemia the serum level of conjugated bilirubin is dramatically increased.
c) in a hemoglobinopathy the globin chains of hemoglobin are structurally altered.
d) in a hemoglobinopathy the globin chains of hemoglobin are insufficiently produced.
C
In an individual with suspected β-thalassemia, which of the following laboratory results would correctly indicate the presence of this disease?
a) Increased hemoglobin concentration, MCV and MCHC with the peripheral blood smear showing increased macrocytes and Howell -Jolly bodies
b) Decreased hemoglobin concentration, MCV and MCHC with the peripheral blood smear indicating microcytosis, target cells and polychromasia
c) Decreased hemoglobin concentration, increased MCV and MCHC and persistence of hemoglobin F with the peripheral blood smear indicating spherocytosis and nucleated red blood cells
d) Increased hemoglobin concentration and normal MCV and MCHC with a normal peripheral blood smear.
B
The role of hemoglobin is to:
a) transport iron between organs.
b) store iron and readily release it when body iron stores are low.
c) reversibly bind oxygen.
d) conjugate bilirubin in the liver.
C
Heme is a:
a) chelate of iron with the four pyrrole groups of a porphyrin.
b) conjugated protein and an oxygen-carrying pigment of the erythrocytes
c) protein found in red skeletal muscle that releases oxygen.
d) colorless compound formed in the intestines by the reduction of bilirubin.
A
Describe the principle of the cyanmethemoglobin method of hemoglobin determination.
Blood is diluted in a solution containing potassium cyanide and potassium ferricyanide. The latter converts Hb to methemoglobin which is converted to cyanmethemoglobin (HiCN) by potassium cyanide. The absorbance of the solution is then measured in a spectrophotometer at a wavelength of 540nm or in a colorimeter using a yellow green filter.
List five analytical methods used to assess the presence of a hemoglobinopathy or thalassemia
FSC + frotis HPLC Électrophorèse sur gel d’agarose Électrophorèse capillaire Electrospray mass spectroscopy DNA analysis
List four different types of hemoglobin and state the makeup of the globin chains in each.
HbA = 2xalpha + 2 x beta HbF = 2xalpha + 2xgamma HbA2 = 2xalpha + 2xdelta Hb H = 4 x beta Hb bart = 4xgamma
Describe the structure and physiological role of hemoglobin.
Complexe protéique du GR formé de tétramère de globine, d’hème et de fer. Lie de façons réversible l’O2 pour permettre les échanges gazeux entre sang/poumons/tissus.
