Organization of pp60src and selected cytoskeletal proteins within adhesion plaques and junctions of Rous sarcoma virus-transformed rat cells.

The localization of pp60src within adhesion structures of epithelioid rat kidney cells transformed by the Schmidt-Ruppin strain of Rous sarcoma virus was compared to the organization of actin, alpha-actinin, vinculin (a 130,000-dalton protein), tubulin, and the 58,000-dalton intermediate filament protein. The adhesion structures included both adhesion plaques and previously uncharacterized adhesive regions formed at cell-cell junctions. We have termed these latter structures "adhesion junctions." Both adhesion plaques and adhesion junctions were identified by interference-reflection microscopy and compared to the location of pp60src and the various cytoskeletal proteins by double fluorescence. The results demonstrated that the src gene product was found within both adhesion plaques and the adhesion junctions. In addition, actin, alpha-actinin, and vinculin were also localized within the same pp60src-containing adhesion structures. In contrast, tubulin and the 58,000-dalton intermediate filament protein were not associated with either adhesion plaques or adhesion junctions. Both adhesion plaques and adhesion junctions were isolated as substratum-bound structures and characterized by scanning electron microscopy. Immunofluorescence revealed that pp60src, actin, alpha-actinin, and vinculin were organized within specific regions of the adhesion junctions. Heavy accumulations of actin and alpha-actinin were found on both sides of the junctions with a narrow gap of unstained material at the midline, whereas pp60src stain was more intense in this central region. Antibody to vinculin stained double narrow lines defining the periphery of the junctional complexes but was excluded from the intervening region. In addition, the distribution of vinculin relative to pp60src within adhesion plaques suggested an inverse relationship between the presence of these two proteins. Overall, these results establish a close link between the src gene product and components of the cytoskeleton and implicate the adhesion plaques and adhesion junctions in the mechanism of Rous sarcoma virus-induced transformation.

Evaluation of an atypical HIV type 1 antibody. Serologic pattern leading to detection of HIV type 2 infection in North America.

The variability and discordance of human immunodeficiency virus type 1 (HIV-1) antibody enzyme immunoassay determinations on serial specimens derived, to our knowledge, from the first documented case of HIV-2 infection in North America are described. The initial specimen was weakly reactive, but two subsequent serum specimens were both nonreactive by enzyme immunoassay. All specimens were indeterminate for HIV-1 antibody by HIV-1 Western blot analysis. Serum HIV-2 antibody was demonstrated by enzyme immunoassay using whole virus lysate, HIV-2-specific synthetic peptide assays, and HIV-2 Western blot analysis. Human immunodeficiency virus type 2 genomic sequences were demonstrated in peripheral blood mononuclear cells using gene amplification technology. Human immunodeficiency virus type 2, isolated from peripheral blood lymphocytes, had typical morphologic features of lenti-virus by electron microscopy. Western blot analysis and other specific assays should be considered in individuals with clinical evidence suggesting HIV infection who are nonreactive for HIV-1 antibody by enzyme immunoassay or who have atypical reactivity patterns.

A statistical test of the stability assumption inherent in empirical estimates of economic depreciation.

Realistic estimates of economic depreciation are required for analyses of tax policy, economic growth and production, and national income and wealth. THe purpose of this paper is to examine the stability assumption underlying the econometric derivation of empirical estimates of economic depreciation for industrial machinery and and equipment. The results suggest that a reasonable stability of economic depreciation rates of decline may exist over time. Thus, the assumption of a constant rate of economic depreciation may be a reasonable approximation for further empirical economic analyses.

What's new in subacute care?

What's new in subacute care? Despite growth, the industry has yet to prove it can deliver the cost savings it has promised, according to a recently released study. Moreover, after all these years much disagreement remains over just what is meant by the term ¿subacute care.¿

1996 outlook: systems, for-profit chains, medical groups, religious healthcare, managed care, post-acute care, finance, purchasing, info systems, labor, legal, construction.

It's put-up-or-shut-up time for healthcare providers in 1996. Two years ago, everyone talked about fixing the healthcare system. Not much happened. Last year, providers and politicians concentrated on squeezing medical costs. According to some of Modern Healthcare's key beat reports, this year it's back to the basics of running a business.

Guidelines for the establishment of written agreements between colleges and clinical affiliates.

If a program in radiologic technology is to consist of a sponsoring institution with one or more clinical affiliates, it is necessary that each party understand and be willing to cooperate in this endeavor. However, understanding and cooperation are dependent upon the degree of involvement each has had in the decision-making process. Once responsibilities are decided upon, each party must agree to abide by the terms. It is with this in mind that we present some guidelines and a suggested format for written agreements.