Publications by authors named "Hajibagheri N"

Evidence for a possible aetiopathogenetic role of endogenous and/or exogenous retroviruses (RVs) in organ- and non-organ-specific autoimmune diseases is circumstantial in both humans and animal models. Intracisternal A type particles, antigenically related to HIV, have been reported in H9 cells co-cultured with homogenates of salivary glands obtained from patients with Sjögren syndrome and with synovial fluid of patients with rheumatoid arthritis. In order to identify a possible transfer of a putative 'infective RV agent' involved in the pathogenesis of human thyroid autoimmune disease, the H9 T cell line was co-cultured not only with thyroid homogenates, but also with viable thyrocytes, both prepared from glands of patients with Graves' disease.

View Article and Find Full Text PDF

Eukaryotic cells encode two homologs of Escherichia coli RecA protein, Rad51 and Dmc1, which are required for meiotic recombination. Rad51, like E.coli RecA, forms helical nucleoprotein filaments that promote joint molecule and heteroduplex DNA formation.

View Article and Find Full Text PDF

Genetic recombination can lead to the formation of intermediates in which DNA molecules are linked by Holliday junctions. Movement of a junction along DNA, by a process known as branch migration, leads to heteroduplex formation, whereas resolution of a junction completes the recombination process. Holliday junctions can be resolved in either of two ways, yielding products in which there has, or has not, been an exchange of flanking markers.

View Article and Find Full Text PDF

The human Rad52 protein stimulates joint molecule formation by hRad51, a homologue of Escherichia coli RecA protein. Electron microscopic analysis of hRad52 shows that it self-associates to form ring structures with a diameter of approximately 10 nm. Each ring contains a hole at its centre.

View Article and Find Full Text PDF

On initiation of terminal differentiation human epidermal keratinocytes detach from the underlying basement membrane as a result of inactivation and subsequent loss of integrins from the cell surface. Assembly of keratinocytes into multilayered sheets requires functional E- and P-cadherin and when stratification is inhibited in low calcium medium differentiating keratinocytes continue to express functional integrins. Using immunofluorescence microscopy, we found that on addition of calcium ions to keratinocyte monolayers there was colocalisation of the beta 1 integrins and E-cadherin along the lateral membranes except for a zone close to the substratum which exclusively contained integrins.

View Article and Find Full Text PDF

The human Rad51 protein is a structural homolog of Escherichia coli RecA. The exact role of human Rad51 within the cell is poorly understood but, like its bacterial and yeast homologs, hRad51 is believed to play a central role in homologous recombination. However, recent reports that transgenic mice lacking the RAD51 gene die early in development suggest an additional and essential function for mammalian Rad51 in cell proliferation or genome maintenance.

View Article and Find Full Text PDF

Apoptosis as a form of programmed cell death (PCD) in multicellular organisms is a well-established genetically controlled process that leads to elimination of unnecessary or damaged cells. Recently, PCD has also been described for unicellular organisms as a process for the socially advantageous regulation of cell survival. The human Bcl-2 family member Bak induces apoptosis in mammalian cells which is counteracted by the Bcl-x(L) protein.

View Article and Find Full Text PDF

Immature secretory granules (ISGs) in endocrine and neuroendocrine cells have been shown by morphological techniques to be partially clathrin coated (Orci, L., M. Ravazzola, M.

View Article and Find Full Text PDF

Resident bone marrow macrophages (RBMM) play an important role in clearance of nuclei extruded from late-stage erythroblasts (Eb). To investigate the nature of macrophage receptors involved in this process, extruded erythroblast nuclei (EEN) were purified by cultivation of erythroblasts with erythropoietin, followed by density gradient centrifugation. By electron microscopy, the majority of free nuclei had an intact plasma membrane.

View Article and Find Full Text PDF

Within the hematopoietic lineage, the monoclonal antibody (MoAb) CD66 reacts with cells of the granulocyte lineage, but not with the majority of progenitor cells from human bone marrow. Our previous studies have shown that CD66 binds specifically to at least three carcinoembryonic antigen (CEA) superfamily members, ie, CEA itself, nonspecific cross-reacting antigen (NCA), and CGM1, but not to CGM6 (NCA-95). In this report, we show that CD66 will also identify the biliary glycoproteins (BGP).

View Article and Find Full Text PDF

Fission yeast was treated with the anti-microtubule agent, thiabendazole. Cytoplasmic microtubules broke down with a half-time of less than 10 minutes followed closely by the unstacking of Golgi cisternae. The final product appeared to be single Golgi cisternae.

View Article and Find Full Text PDF