Osteogenic capacity of collagen in repair of established periodontal defects.

Periodontal bone defects were established in four dogs, with one proximal lesion and one furcation lesion in each quadrant. These defects were treated with the implantation of collagen membranes, collagen sponge or a combination of membrane and sponge, inserted between the mucoperiosteal flaps and the bone defects. Control sites were treated in a similar surgical manner to the experimental sites, but no collagen was inserted.

Heterogeneity in dermatosparaxis is shown by contraction of collagen gels.

Dermal fibroblasts from sheep exhibiting a mild form of dermatosparaxis were able to contract reconstituted, fibrillar collagen gels at the same rate as control dermal fibroblasts, indicating a normal interaction between the cells and a collagenous matrix. An extract from dermatosparactic skin was shown, after partial purification, to have N-proteinase activity, although the level of activity was much lower than found in normal skin. These data show that dermatosparaxis is a heterogeneous disease, since in the severe forms of the disease the defect has been characterized as an absence of N-proteinase and an inability of the cells to interact with and contract collagen gels.

The effect of infectious bursal disease virus on B lymphocytes and bursal stromal components in specific pathogen-free (SPF) White Leghorn chickens.

The effect of infectious bursal disease virus (IBDV) was studied on adult specific pathogen-free (SPF) white Leghorn chickens through analysis of peripheral blood cell suspensions and histological staining patterns on various tissue types, with specific mAbs. A rapid, progressive loss of B lymphocytes was observed in the bursal cortex and medulla, peripheral blood and thymic medulla. There was, however, a resistant population of MUI-36+ cells at the bursal cortico-medullary junction and scattered around splenic periellipsoidal sheaths.

In vitro production of Reichert's membrane by mouse embryo-derived parietal endoderm cell lines.

We report the isolation of eight independent cell lines from preimplantation mouse embryos, which have a parietal endoderm phenotype. When grown as aggregates, these cell lines produce large amounts of a basement membrane matrix, that contains laminin, nidogen, heparan sulfate proteoglycan, collagen IV, and BM-40. The biosynthetic profiles of all eight cell lines are very similar to parietal endoderm cells in vivo which synthesize Reichert's membrane.

Phenotypic characterization of chicken bursal stromal elements.

Many, if not all, of the different phases of intrabursal B-cell maturation are controlled by the stromal components. We have used an extensive panel of mAb to provide a detailed phenotypic profile of these cells. Antigenic specificities were defined for the entire surface epithelium, interfollicular surface epithelium, follicle-associated epithelium, basement membrane, basement membrane-associated epithelium.