Physico-chemical properties of a protein-inhibitor of serine proteinases from the potato]

Serine proteases inhibitor with pl-7.3, isolated from potatoe tubers by isoelectric focusing procedure as described previously (V.V. Mosolov et al., Bioorganic Chem., 1, 1449, 1975), was homogeneous under ultracentrifugation, having sedimentation coefficient S20,w 2.8S. Its molecular weight, investigated by sedimentation equilibrium and gel filtration through Sephadex G-100, was found to be 32500 and 31500 respectively. The Stokes radius R and frictional ratio f/fo were found to be 24 A and 1.14. The molecular weight of the inhibitor as determined by sodium dodecylsulfate polyacrylamide electrophoresis was twice as low as determined in ultracentrifuge and by gel filtration procedure. It is suggested that the inhibitor is dimer and consists of two protomers of equal molecular weight.     

Large area cylindrical silicon drift detector

An advanced silicon drift detector, a large-area cylindrical drift detector, was developed. The authors focus on the design aspects of the detector. They study the transport of electrons in a cylindrical geometry. The consequences of the transport analysis for the pitch of anodes and for the number of readout channels is shown. The flow of the leakage current generated at the Si-SiO₂ interface into a sink anode is considered. The diversion of the leakage current away from the signal anodes improves the performance of the detector. The increase of the current generation on the Si-SiO₂ interface due to anticipated radiation damage effects the detector less. Some results obtained from laboratory tests and from the operation of the detector at the NA45 experiment at CERN are shown     

Stable chronic disease: a behavioral model

A three-year study was undertaken in the general medical clinic of a private community hospital, to assess the health behavior, health status, and profile of function of stable chronic disease was developed and tested. It was shown that these patients used a disproportionate amount of health care services. Half of the group was treated by a nurse practitioner/physician team and half by a house officer/preceptor team. Patients in both groups behaved similarly. These patients: 1) made frequent demands for outpatient services but did not need more than average hospital care; 2) tended to have problems of socio-economic indigency; 3) were likely to have hypertension, obesity, arthritis, and functional disease; 4) were chiefly women; 5) required special visits 9 percent of the time, usually for exacerbations of illness or intercurrent health problems; 6) made greater demands if they had functional complaints as a primary or secondary health problem; and 7) viewed their health more positively and functioned at a higher level if they were over 65 years of age. It was also found that the nurse practitioner, working in consultation with a physician, was able to provide high-quality health care.     

The mechanism of the development of the synapse as the basis for its involution

The electron microscopic investigation of human brain synaptic organization in normal aging and in ischemic heart pathology in different life periods was performed. A significant quantity of desmosome-like and mixed contacts was shown. Their ultrastructural organization was similar to that of developing synapses during prenatal ontogenesis and in newborn rats. The analysis of the experimental results suggests that an appearance of desmosome-like contacts in the human brain results from synapse involution. This is supported by the observation of formation of mixed contacts which may be a transitional stage between symmetrical or asymmetrical specialized synapse and desmosome. Thus, the mechanism of synaptic involution appears to be a mirror reflection of the mechanism of its development.     

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.