Leptocyte Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Leptocyte and links to relevant pages within the course.
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| Hemoglobin H disease Hemoblobin H disease follows deletions of 3 of the 4 alpha globulin chains. Beta chains, unable to bind with insufficient numbers of alpha chains, form beta chain tetramers, or HbH.These beta chain tetramers appear as numerous dot size inclusions in erythrocyte cytoplasm, best seen in supravital brilliant cresyl blue stains (lower photograph).The most common molecular defect in alpha thalassemia is DELETION, not MUTATION; whereas, in beta thalassemia, the molecular defect is MUTATION.Leptocytes, as illustrated in the upper photograph,(lepto, derived from a Greek word meaning thin, fine, or slight), are characteristic of HbH disease. They have thinner cell membranes than the cells we recognize as target cells. They stain more lightly than normal erythrocytes and their centers are almost colorless.Subtle changes perhaps, but worth keeping in mind | View Page |
| The patient, an 8-month-old girl, was anemic, jaundiced, and had splenomegaly. Her family had immigrated from the Middle East. Based on the history and the peripheral blood picture, the most probable diagnosis is thalassemia. | View Page |
| Leptocytes and target cells The peripheral blood smear of HbH disease presented before is reviewed in the upper photograph.As mentioned, these leptocytes are pale-staining with hemoglobin confined to a thin, flat, cell membrane.Illustrated in the lower photograph are target cells or codocytes (a term derived from a Greek word for hat)Membrane accumulations of phospholipids and cholesterol (particularly in obstructive jaundice) promote target cell formation.When these cells are spread out on a glass slide, a central bump of hemoglobin appears to produce the target, a manifestation of excess cellular membrane compared to the amount of hemoglobin inside.The early descriptions of thalassemias, then called hereditary leptocytosis (Mediterranean anemia, Cooley's anemia), include description of leptocyes, which may have represented HbH disease. | View Page |
| Which of the following terms could be used to describe the cell in the center of the field? | View Page |
| Pseudomacrocytes Another type of macrocyte can be seen in the center of this slide. Notice it appears larger than the lymphocyte but in contrast to megalocytes has an area of central pallor. These macrocytes are sometimes referred to as "pseudo macrocytes," since their size is the result of exaggerated flattening (leptocyte) and thus the presence of the central pallor. The MCV for this type of macrocyte is within normal range. Pseudomacrocytes can be seen in patients with cirrhosis of the liver, obstructive jaundice, post splenectomy and conditions that affect the red cell membrane. | View Page |
| Synonyms for Codocytes Synonyms for a Codocyte include target cell, Mexican hat cell, and Leptocyte(thin). | View Page |