Lysosomal enzyme cytochemistry in acute leukaemia

A cytochemical study of the lysosomal enzyme beta-glucuronidase in 60 cases of acute leukaemia has shown a qualitative difference in the cytoplasmic distribution of the enzyme between blast cells of the lymphoid and myeloid cell series. This difference provides a useful additional method for cytochemical classification of cell type and is superior in this respect to the other lysosomal enzymes studied (aryl sulphatase and acid phosphatase). The beta-glucuronidase reaction is recommended in those cases of acute leukaemia in which the periodic acid-Schiff reaction is negative or equivocal.

Activity of human placental sulfatase and 11 -hydroxysteroid dehydrogenase with respect to steroids of the pregn-4-ene C-21-yl sulfate series

Sulfatase and 11β-hydroxysteroid dehydrogenase activities of human placenta were studied with respect to four steroids of the pregn-4-ene C-21-yl-sulfate series. Homogenates, as well as the microsomal fraction of placenta obtained either at midterm or at term, possessed negligible sulfatase activity with respect to the sulfates of 11-dehydrocorticosterone and corticosterone, and low but consistent activity towards 11-deoxycorticosterone sulfate. Under the same conditions dehydroepiandrosterone sulfate was hydrolyzed almost quantitatively.Placental homogenates converted cortisol to cortisone and corticosterone to 11-dehydrocorticosterone. The reaction was greatly enhanced by the addition of NADP. In contrast, the corresponding 11β-hydroxy-C-21 steroid sulfates were poor substrates with respect to placental 11β-hydroxysteroid dehydrogenase, as indicated by the low yields of the sulfates of cortisone and 11-dehydrocorticosterone, even in the presence of NADP. These findings are consistent with the pattern of steroids of the pregn-4-ene series characterized in human cord plasma.

Neuronal GM1 gangliosidosis in a Siamese cat with beta-galactosidase deficiency

A juvenile Siamese cat with severe, progressive motor disability was shown to have extensive neuronal degeneration caused by accumulation of GM(1) ganglioside. Tissues from brain and kidney were markedly deficient in beta-galactosidase activity. The disease in this cat is thought to be inherited as an autosomal recessive trait, and is strikingly similar to juvenile GM(1) gangliosidosis of children.

The development of neutrophilic polymorphonuclear leukocytes in human bone marrow

Neutrophilic leukocytes (PMN) and their precursors from normal human marrow and blood were examined by histochemical staining and by electron microscopy and cytochemistry in order to determine the origin and nature of their cytoplasmic granules. Human neutrophils contain two basic types of granules, azurophils and specifics, which differ in morphology, contents, and time of origin. Azurophils are large and may be spherical or ellipsoid, the latter with a crystalline inclusion. They are produced in the first secretory stage (promyelocyte), contain peroxidase and various lysosomal enzymes, and thus correspond to modified primary lysosomes. Specifics are smaller, may be spherical or elongated, and are formed during a later secretory stage (myelocyte). They lack lysosomal enzymes and contain alkaline phosphatase and basic protein; their contents remain largely undetermined. Specifics outnumber azurophils in the mature PMN because of reduction in numbers of azurophils per cell by cell division in the myelocyte stage. The findings indicate that the situation is basically the same as described previously in the rabbit, insofar as the origin, enzymic activity, and persistence in the mature cell of the two types (azurophil and specific) of granules are concerned. The main difference between PMN of the two species is in the morphology (size, shape, and density) of the granules, especially the azurophils.

Differentiation of monocytes. Origin, nature, and fate of their azurophil granules

The origin, content, and fate of azurophil granules of blood monocytes were investigated in several species (rabbit, guinea pig, human) by electron microscopy and cytochemistry. The life cycle of monocytes consists of maturation in bone marrow, transit in blood, and migration into tissues where they function as macrophages. Cells were examined from all three phases. It was found that: azurophil granules originate in the Golgi complex of the developing monocyte of bone marrow and blood, and ultimately fuse with phagosomes during phagocytosis upon arrival of monocytes in the tissues. They contain lysosomal enzymes in all species studied and peroxidase in the guinea pig and human. These enzymes are produced by the same pathway as other secretory products (i.e., they are segregated in the rough ER and packaged into granules in the Golgi complex). The findings demonstrate that the azurophil granules of monocytes are primary lysosomes or storage granules comparable to the azurophils of polymorphonuclear leukocytes and the specific granules of eosinophils. Macrophages from peritoneal exudates (72-96 hr after endotoxin injection) contain large quantities of lysosomal enzymes throughout the secretory apparatus (rough ER and Golgi complex), in digestive vacuoles, and in numerous coated vesicles; however, they lack forming or mature azurophil granules. Hence it appears that the monocyte produces two types of primary lysosomes during different phases of its life cycle-azurophil granules made by developing monocytes in bone marrow or blood, and coated vesicles made by macrophages in tissues and body cavities.