Dentosphere : World of Dentistry

 # Howell–Jolly bodies contain:  a. Iron  b. DNA  c. RNA  d. Protein The correct answer is B. DNA. A Howell–Jolly body is a cytopathological finding of basophilic nuclear remnants (clusters of DNA) in circulating erythrocytes. During maturation in the bone marrow, late erythroblasts normally expel their nuclei; but, in some cases, a small portion of DNA remains. CLICK HERE FOR MORE MCQs

 # Pappenheimer bodies contain:  a. Iron  b. DNA  c. RNA  d. Ribosomal proteins The correct answer is a. Iron. Pappenheimer bodies are abnormal basophilic granules of iron found inside red blood cells on routine blood stain. They are a type of inclusion body composed of ferritin aggregates, or mitochondria or phagosomes containing aggregated ferritin. CLICK HERE FOR MORE MCQs

 # Membrane rigidity and fragility can be measured by: a. Osmocytometer b. Spherocytometer c. Ektacytometer d. Viscometer The correct answer is C. Ektacytometer.  Osmotic gradient ektacytometry measures RBC deformability under a defined shear stress as a function of suspending medium osmolality. The test is used to evaluate for inherited RBC membrane disorders, which are commonly responsible for hemolytic anemia, differentiating among hereditary spherocytosis (HS), hereditary elliptocytosis (HE) and pyropoikilocytosis (HPP), Southeast Asian ovalocytosis (SAO) and hereditary stomatocytosis (HSt). Osmotic Gradient Ektacytometry at Cincinnati Children's.Ektacytometry is recommended as the next step after hemoglobin electrophoresis in the diagnosis of a non-immune hemolytic anemia. An abnormal ektacytometry profile confirms a red cell membrane disorder and assists with the differential diagnosis between hereditary spherocytosis versus elliptocytosis / pyropoikilocytosis versus xer...

 # Typical dominant HS is most commonly caused by deficiency of:  a. Ankyrin  b. Band 3  c. Spectrin  d. Protein 4.2 The correct answer is A. Ankyrin. The most common cause of typical dominant HS (2/3rd of cases) is ankyrin defect. Band 3 defect and isolated spectrin deficiency is next common. The degree of spectrin deficiency correlates with spheroidicity, ability of red cells to withstand shear stress, degree of hemolysis and response to  splenectomy. Protein 4.2 deficiency is inherited as autosomal recessive trait. Severe HS almost always have recessive inheritance and most have severe spectrin deficiency (< 40%) may be d/t defect in β-spectrin.  CLICK HERE FOR MORE MCQs

 # Which of the following have decreased osmotic fragility?  a. Hereditary spherocytosis  b. Hereditary elliptocytosis  c. Hereditary xerocytosis  d. Hereditary stomatocytosis/hydrocytosis The correct answer is C. Hereditary xerocytosis. Osmotic fragility has been typically increased in Hereditary spherocytosis and hereditary  elliptocytosis. There are 2 types of hereditary stomatocytosis: hereditary xerocytosis (complex permeability defect d/t increased membrane lipids) and hereditary stomatocytosis – hydrocytosis (d/t deficiency of band 7.2b or stomatin). Both have autosomal dominant inheritance. Osmotic fragility is decreased in xerocytosis and increased in hydrocytosis. Xerocytosis may result in recurrent fetal loss, hydrops fetalis, neonatal hepatitis and familial pseudohyperkalemia. CLICK HERE FOR MORE MCQs

 Which of the following is a major risk factor for venous thrombosis? a. Smoking b. High cholesterol c. Hypertension d. Diabetes mellitus e. Cancer The correct answer is E. Cancer. Venous thrombosis, including deep vein thrombosis and pulmonary embolism, occurs at an annual incidence of about 1 per 1000 adults. Rates increase sharply after around age 45 years, and are slightly higher in men than women in older age. Major risk factors for thrombosis, other than age, include exogenous factors such as surgery, hospitalization, immobility, trauma, pregnancy and the puerperium and hormone use, and endogenous factors such as cancer, obesity, and inherited and acquired disorders of hypercoagulation.  Ref: Cushman M. Epidemiology and risk factors for venous thrombosis. Semin Hematol. 2007;44(2):62-69. doi:10.1053/j.seminhematol.2007.02.004 CLICK HERE FOR MORE MCQs  

# Commonest inherited cause of thrombosis in Caucasians is: a. Protein S deficiency b. Factor V leiden mutation c. Anti thrombin III deficiency d. Protein C deficiency The correct answer is B. Factor V Leiden mutation. Factor V Leiden (G1691A or arg 506 glu substitution) and prothrombin (G 20210 A) are rare in African and orientals but they have prevalence in whites, highest prevalence of heterozygotes (11–14%) is reported in Sweden and Arabs. CLICK HERE FOR MORE MCQs