Ex vivo differentiation of umbilical cord blood progenitor cells in the presence of placental conditioned medium.

Hematopoetic stem cells (HSC) are the progenitors for the lympho-hematopoietic system, with long lifespan and high proliferation potential. Transplantation of HSC from bone marrow or peripheral blood represents a standard therapy in severe hematological conditions. A possible alternative source of HSC is the umbilical cord blood, prepared by various separation procedures followed by expansion in cultures supplemented with hematopoietic growth factors.

Ultrastructural modifications at uterine cervix level induced by human papillomaviruses infections.

The paper presents the ultrastructural modifications occurring in uterine cervix epithelium in 10 patients with clinical susceptibility of HPV infections. The presence of viral HPV particles was identified in 5 cases and in 1 case the concomitant presence of both HPV and HSV2 particles was detected. The maximum amount of HPV virions is found in the spinous and superficial layer, particularly in the nucleus, but also in cytoplasm.

Ultrastructural modifications in mice spleen after "Imunotim' treatment.

Imunotim, a polypeptidic extract from bovine thymus, induces the appearance of barrier cells in the spleen; these cells form a syncytial network and play an important role in blood cleaning. They are of fibroblastic origin. The cytoplasm of the cells in the network is dense and contains vesicles that seem to be detached from the nucleolemma.

Phospholipids and gangliosides in the Rous sarcoma.

Ten days after inoculation of sarcomatous homogenate in the leg muscle of chickens, the appearance of sarcomatous tumours was observed by electron microscopy. Viral replication and cell transformation strongly altered phospholipids and glycolipids content of the tissue: 6.12 +/- 0.

Viral particles in the hepatocytes of Rana esculenta (L).

The hepatocytes of Rana esculenta exhibit hexagonal, probably icosahedral, viral particles disseminated in the cytoplasm among cellular organelles (mitochondria, cisternae of the endoplasmic reticulum, Golgi complex). The particles consist of an electron-dense core (nucleoid) and a less electron-dense envelope (capsid). Empty capsids (without nucleoid) or semilunar capsid fragments can be sometimes observed.