Gap junctional intercellular communication contributes to the contraction of rat osteoblast populated collagen lattices

The contraction of native collagen lattices by resident mesenchymal cells mimics the organization of collagen during development and repair. Lattice contraction is cell density dependent, suggesting that cell-to-cell communications may contribute to the process. This possibility was investigated by comparing lattice contraction by four rat osteoblastic cell lines: ROS 17/2.8 cells (ROS); ROS transfected with an antisense cDNA sequence of the gap junctional protein connexin 43 (RCx16); ROS transfected with connexin 45 cDNA, a connexin not normally expressed in ROS cells (ROS/Cx45); and ROS transfected with cDNA encoding carboxy-terminal truncated Cx45 (ROS/Cx45tr). The cell coupling indices, which reflect gap junctional communication, were quantitated by the fluorescent dye scrape loading. ROS cells were well coupled (index 3.0), ROS/Cx45tr were better coupled (index 4.2), ROS/Cx45 were poorly coupled (index 1.7), and RCx16 showed no coupling (index 1.1). As determined by immunoblotting, the level of connexin 43 protein was increased in both ROS/Cx45tr and ROS/Cx45 cell lines compared with ROS cells, while the level in RCx16 cells was reduced. ROS populated collagen lattices (PCLs) contracted significantly more at day 5 (177 mm2 to 67 mm2) than ROS/Cx45tr (84 mm2), ROS/Cx45 (108 mm2), or RCx16 (114 mm2). Myosin ATPase activity, which is required for lattice contraction, was equivalent in all four cell lines, indicating that it was not responsible for inhibiting PCL contraction. ROS cells in collagen appeared elongated compared with the other cell lines which were more rounded. These experiments suggest gap junctional communication contributes to PCL contraction by resident osteoblasts.     

Prediction of major depression and dysthymia from CES-D scores among ethnic minority adolescents

Two tumour cell clones, 6D1 and 4C2 cells, which are defective both in the major histocompatibility gene complex (MHC) class I expression and in the endogenous antigen presentation, are recovered with interferon (IFN)-gamma treatment. The present study describes the ultrastructure of these cells by using scanning and transmission electron microscopy in relation to the effect of IFN-gamma treatment. The general morphology of these cells was found to be similar to each other and comparable to that of a tumour cell clone, 4A1 cells, of the same origin, normal in MHC class I expression; they exhibited a fibroblast-like appearance and had many blebs on all the cell surfaces, with desmosome-like junctions between cells. On IFN-gamma treatment, surface fine blebs appeared less, and mitochondria became more densely stained. Expression of MHC class I molecules on the cell surface was much higher in the IFN-gamma treated 6D1 and 4C2 cells than in untreated cells, when estimated by immunoelectron microscopy. The addition of an epitope peptide to these cells did not enhance the class I expression, which differed from other antigen presentation-defective cells such as RMA-S cells, nor change the cell surface morphology.     

Anti-macrophage monoclonal antibody D-11 in the diagnosis of histiocytic tumors

Anti-macrophage monoclonal antibody (Mab) D-11 was tested in surgical material and biopsies of non-epithelial tumors and tumor-like lesions from 181 patients in order to assess possibility of using this Mab for diagnosis of histiocytic tumors, malignant fibrous histiocytoma in particular. The study was performed in parallel on cryostat sections and smears by immuno-peroxidase method. It is established that D-11 reacts positively with both histiocytic tumors and tumors of other genesis this being a limiting factor in differential diagnosis of histiocytic tumors. However, taking into consideration 100% of positive results with histiocytic tumors only, this antibody can be used for exclusion of tumors studied from the group of histiocytomas in cases of negative reaction.     

EEG pharmacodynamics upon single administration of seduxen in healthy volunteers

We have examined the type I collagen protein, RNA, and cDNA of 2 children with moderately severe (type IV) osteogenesis imperfecta (OI). They have in common a non-lethal form of OI with ambulatory potential, overmodification of type I collagen protein, and a substitution of serine for glycine in the collagen chain produced by one alpha 1(I) allele. The first child (Marini et al.: J Biol Chem 264:11893-11900, 1989) is now 7 years old, with the height of a 3-year-old. Her course includes significant remodeling of lower long bones and 4 femur fractures. She walks independently. A mishmatch was detected in her alpha 1(I) mRNA using RNA/RNA hybrids; it was demonstrated to be due to a G-->A point mutation in one allele of alpha 1(I), resulting in the substitution of serine for glycine 832. The second child is now 6 1/2 years old, with the height of 1 1/2-year-old. Her history includes significant bowing of femurs and tibias, 6 femur fractures, S-curve scoliosis, compression of all lumbar vertebrae, and limited short-distance walking with braces. Her alpha 1(I) mRNA has also been studied by RNA hybrid analysis; there is a single G-->A change in one alpha 1(I) allele causing the substitution of serine for gly 352. Both children have moderately severe OI. However, the serine substitution at gly 352 is associated with a more severe phenotype then is the serine substitution at gly 832. Compared to substitutions described in other cases of OI, the serine 352 is located in the middle of a cluster of cysteine substitutions associated with non-lethal OI.(ABSTRACT TRUNCATED AT 250 WORDS)