Demonstration of a capsule plasmid in Bacillus anthracis

Virulent and certain avirulent strains of Bacillus anthracis harbor a plasmid, designated pXO2, which is involved in the synthesis of capsules. Two classes of rough, noncapsulated (Cap-) variants were isolated from the capsule-producing (Cap+) Pasteur vaccine strains ATCC 6602 and ATCC 4229. One class was cured of pXO2, and the other class still carried it. Reversion to Cap+ was demonstrable only in rough variants which had retained pXO2. Proof that pXO2 is involved in capsule synthesis came from experiments in which the plasmid was transferred by CP-51-mediated transduction and by a mating system in which plasmid transfer is mediated by a Bacillus thuringiensis fertility plasmid, pXO12. Cells of Bacillus cereus and a previously noncapsulated (pXO2-) strain of B. anthracis produced capsules after the acquisition of pXO2.     

Small vessel vasculitis caused by hepatitis B virus immune complexes: Small vessel vasculitis and HBsAg

In a comprehensive study of 80 patients with vasculitis, 4 had concurrent hepatitis B virus (HBV) infection. Polyarteritis nodosa was present in 2 and in the other 2, cutaneous vasculitis, presenting clinically as palpable or Henoch-Schönlein purpura. In one of these patients skin biopsies demonstrated granular deposits of IgM, C3, C4, and the hepatitis B surface antigen (HBsAg) and electron-dense deposits of aggregated 20-nm particles resembling HBsAg in postcapillary venules. Evidence for circulating HBsAg-immune complexes included increased serum C1q binding activity, decreased serum complement, and a cryoprecipitate containing both HBsAg and IgM anti-HBs. Aggregated 20-nm particles resembling intact HBsAg were also seen by negative staining electron microscopy of the serum cryoprecipitate. This patient fulfills all the criteria for a specific immune complex vasculitis caused by his immune response to a chronic HBV infection. These findings emphasize that HBV infection may be associated with small vessel vasculitis as well as polyarteritis nodosa, mixed cryoglobulinemia, and glomerulonephritis. A similar immune response to other viral infections may be expressed as palpable (Henoch-Schönlein) purpura also.     

Eosinophil-activating factor (EAF) production by a human cell line (ESH 98) stimulated with tumour necrosis factor.

A new cell line has been produced by fusing human cervical keratinocytes with HeLa cells. This cell line secretes eosinophil-activating activity upon stimulation with tumour necrosis factor (TNF). About one-third of the eosinophil-activating activity co-purifies with eosinophil-activating factor (EAF) from mononuclear cell supernatants. The purification procedure indicates that it resembles EAF in molecular weight and acidity. It also resembles EAF in its effect on eosinophils. Not only does it enhance the cytotoxic activity of eosinophils to antibody-coated schistosomula of Schistosoma mansoni, but it also increases the oxidative activity of eosinophils, as measured by reduction of nitroblue tetrazolium, and changes the morphology of eosinophils, affecting the distribution of F-actin in the cell.     

Expression and characterization of recombinant soluble human CD3 molecules: presentation of antigenic epitopes defined on the native TCR-CD3 complex

The TCR-CD3 complex consists of the clonotypic disulfide-linked TCRalphabeta or TCRdeltagamma heterodimers, and the invariant CD3delta, epsilon, gamma and zeta chains. We generated plasmid constructs expressing the extracellular domains of the CD3delta, epsilon or gamma subunits fused to human IgG1 Fc. Recombinant fusion proteins consisting of individual CD3delta, epsilon or gamma subunits reacted poorly with anti-CD3 mAb including G19-4, BC3, OKT3 and 64.1. Co-expression of the CD3epsilon-Ig with either the CD3delta-Ig (CD3epsilondelta-Ig) or the CD3gamma-Ig (CD3epsilongamma-Ig) resulted in fusion proteins with much increased binding to G19-4. A brief acid treatment of the purified CD3epsilondelta-Ig fusion protein substantially improved its binding to BC3, OKT3 and 64.1. Surface plasmon resonance analysis revealed that the dissociation constants for CD3epsilondelta-Ig and anti-CD3 mAb ranged from 10(-8) to 10(-9) M. Based on these results, a single-chain (sc) construct encoding the CD3delta chain linked to the CD3epsilon chain with a flexible linker followed by human IgG1 Fc was expressed. The sc CD3deltaepsilon-scIg reacted with anti-CD3 mAb without requiring acid treatment. Moreover, anti-CD3 mAb bound CD3epsilondelta-Ig at a higher affinity than CD3epsilongamma-Ig, suggesting potential structural differences between the CD3epsilondelta and CD3epsilongamma subunits. In summary, we report the expression of soluble recombinant CD3 proteins that demonstrate structural characteristics of the native CD3 complex expressed on the T cell surface. These CD3 fusion proteins can be used to further analyze the structure of the TCR-CD3 complex, and to identify molecules that can interfere with TCR-CD3-mediated signal transduction by disrupting the interaction between CD3 and TCR subunits.     

Field processes in stereovision

There is, as yet, no satisfactory theory of stereopsis, despite the fact that our overt knowledge of solid seeing is now about 150 years old, and that contributions to our understanding come today from many fields: ophthalmology, psychology, psychophysics, neurophysiology, computer modelling, and optical-TV display technology. We review herein, and demonstrate for the reader whenever possible, certain key perceptual properties of the stereoscopic event of which any general theory must take account: vector stereoscopy and the neural grid, depth in empty visual fields, the relationship between stereoscopic and cognitive contours, stereoscopic contour formation in the presence of blur (thus, at low levels of central visual acuity), the phenomenon of cortical locking and of neural grid evocation in the presence of either peripheral or central rivalry, certain unusual ranges of figural mismatch and the concept of the horopter in relation to modern single cell electroneurophysiology in animals and to the constancy of visual directions. Some comments are also made on the concept of disparity processing by single cortical neurons, together with a short discussion of the implications of certain views of the genetics of stereovision for the perception of novel random texture sine-wave stereograms.We conclude that any theory pertinent to ophthalmology and visual science must combine the global concepts of cortical integration, the neural lock and the neural grid, herein introduced, with the more classical concepts of particulate or local binocular cortical correspondence. Certain preliminary steps in this direction are presented.     

State perspectives on health care reform: Oregon, Hawaii, Tennessee, and Rhode Island

The general consensus among States which have had their section 1115 demonstration projects approved is that there is no one best way to implement State health care reform. The Health Care Financing Administration (HCFA), however, wished to discern how States were accomplishing the task of implementing the demonstrations, and solicited responses from State representatives whose section 1115 demonstration waivers had been approved. The resulting article gives an overview of this implementation process from four State perspectives. Written by representatives from Oregon, Hawaii, Tennessee, and Rhode Island, the ideas presented here are indicative of the complex undertaking of State health care reform.     

Living with diabetes as a transformational experience

The construct of transformation has been presented in many research studies as the epitome of living with a chronic illness. Because it has been inadequately defined, however, many other concepts (e.g., hope, meaning, control) are used in ways that suggest considerable overlap and correspondence with transformation. This article represents an attempt to explicate the structures and processes of transformation as they were revealed in a qualitative inquiry into the experience of individuals with Type I diabetes. In the accounts constructed with participants in this study, the process of personal transformation was significant in the attainment of healthy outcomes. The authors describe this transformation and examine its relationship to control and to the valued outcomes of intensified sense of self, meaning, and mastery.