Ultrastructural study of epidermal Langherhans cells in leprosy.

ATPase staining and ultrastructural study of skin biopsies from six patients of leprosy (2TT, 4LL) and three normal subjects was carried out to study Langherhans Cells (LC). ATPase staining showed normal counts of LCs in tuberculoid patients, while significant reduction was observed in lepromatous cases. Electron microscopy revealed morphological changes in LL cases in the form of dense matrix and indistinct cristae of mitochondria; decreased number of lysosomes and rough endoplasmic reticulum; and numerous vacuoles in cytoplasm. TT cases showed normal morphology. Possible role of Langerhans Cells in pathogenesis of leprosy is discussed.

Effect of phospholipase-D on rat kidney mitochondria.

Incubation of purified rat kidney mitochondrial fraction with phospholipase- D resulted in the accumulation of phosphatidic acid in the membrane due to the degradation of membrane-bound phosphatidylcholine, -serine and -ethanolamine Simultaneously with the hydrolysis of the phospholipids, cholesterol and protein were released from the mitochondrial membrane into the medium, and binding of Ca2+ by mitochondrial membranes increased. Phospholipase Dtreated mitochondrial fraction exhibited increased swelling in vitro in the early stages of incubation (15 min) after which the mitochondria were ruptured. Membrane- bound adenosine triphosphatase was partially inactivated and the enzyme activity was not significantly restored by incubation with sonicated dispersions of phosphatidylcholine, -serine and cholesterol. These results indicate that removal of choline, serine and ethanolamine from membrane-bound phospholipids disrupt phospholipid-cholesterol and phospholipid-protein association and affect functions of the membrane.