S-100 dendritic cells in normal and Dermatobia hominis infested cattle skin

S-100 dendritic cells immunolabeling were investigated in uninfested skin biopsies from five Nelores, five Holstein-Friesian and five crossbreed (Holstein-Friesian x Nelores) calves. The group of crossbreed animal was experimentally infested with 100 first-instar larvae of Dermatobia hominis and biopsies were obtained 24, 48, 72 and 168 hours after infestation. Samples obtained prior to infestation from these animals were used as control. Rabbit anti-protein S-100 antibody and the avidin-biotin-peroxidase method were used for immunolabeling. Melanocytes, nerves and endothelial cells and dermal dendritic cells (DC) were positive to protein S-100. DCs were exclusively detected in the superficial dermis close to the basal layer of both normal and parasitized animals. There was no significant difference in DC numbers that might be attributed to breed. In parasitized animals the DC had thicker and deeply stained dendritic processes compared to normal animals. Statistically significant decreases in the DC number occurred after infestation

Occurrence of "nuages" and "lamellae anulata" during spermatogenesis in Dermatobia hominis (Diptera: Cuterebridae)

Various types of "nuages" and "lamellae anulata" can be found during Dermatobia hominis spermatogenesis. In spermatogonia, the "nuages" occur as granules juxtaposed to the cytoplasmic face of the nuclear envelope or as cytoplasmic granules similar to glycogen granules. In spermatocytes, in addition to the "nuages", dense spherical bodies of approximately 1.0 µm in diameter are also observed. In the spermatids the "nuages" can be of the following types: perinuclear granules, spherical granules with diameters varying in length from 0.5 to 1.0 µm, granules similar to glycogen granules, granules with variable diameters which accumulate at the flagellum base forming the centriole adjunct, or remain in the cytoplasm. "Nuages" can also be observed in these cellular types as dense masses, without a definite outline and are common to animal germinal cells in general. The "lamellae anulata" on the other hand, are observed only in spermatocytes I and in early spermatids, being always immersed in electron-dense material of indefinite outline. In spermatids, the "lamellae anulata" are close to the nuclear envelope suggesting, in spite of opposing opinions, that these cells are envolved in the synthesis and transport of material from the nucleus to the cytoplasm.