Cryo-electron microscopy study of bacteriophage T4 displaying anthrax toxin proteins

The bacteriophage T4 capsid contains two accessory surface proteins, the small outer capsid protein (Soc, 870 copies) and the highly antigenic outer capsid protein (Hoc, 155 copies). As these are dispensable for capsid formation, they can be used for displaying proteins and macromolecular complexes on the T4 capsid surface. Anthrax toxin components were attached to the T4 capsid as a fusion protein of the N-terminal domain of the anthrax lethal factor (LFn) with Soc. The LFn-Soc fusion protein was complexed in vitro with Hoc(-)Soc(-)T4 phage. Subsequently, cleaved anthrax protective antigen heptamers (PA63)(7) were attached to the exposed LFn domains. A cryo-electron microscopy study of the decorated T4 particles shows the complex of PA63 heptamers with LFn-Soc on the phage surface. Although the cryo-electron microscopy reconstruction is unable to differentiate on its own between different proposed models of the anthrax toxin, the density is consistent with a model that had predicted the orientation and position of three LFn molecules bound to one PA63 heptamer.     

Suggestive evidence of a locus on chromosome 10p using the NIMH genetics initiative bipolar affective disorder pedigrees

As part of a four-center NIMH Genetics Initiative on Bipolar Disorder, a genome screen using 365 markers was performed on 540 DNAs from 97 families, enriched for affected relative pairs. This is the largest uniformly ascertained and assessed linkage sample for this disease, and includes 232 subjects diagnosed with bipolar I (BPI), 32 with schizo-affective, bipolar type (SABP), 72 with bipolar II (BPII), and 88 with unipolar recurrent depression (UPR). A hierarchical set of definitions of affected status was examined. Under Model I, affected individuals were those with a diagnosis of BPI or SABP, Model II included as affected those fitting Model I plus BPII, and Model III included those fitting Model II plus UPR. This data set was previously analyzed using primarily affected sib pair methods. We report the results of nonparametric linkage analyses of the extended pedigree structure using the program Genehunter Plus. The strongest finding was a lod score of 2.5 obtained on chromosome 10 near the marker D10S1423 with diagnosis as defined under Model II. This region has been previously implicated in genome-wide studies of schizophrenia and bipolar disorder. Other chromosomal regions with lod scores over 1.50 for at least one Model Included chromosomes 8 (Model III), 16 (Model III), and 20 (Model I). Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:18-23, 2000 Copyright 2000 Wiley-Liss, Inc.     

A Theoretical Model of Transition to Practice for Athletic Trainers

ContextThe transition to practice of newly credentialed athletic trainers (ATs) has become an area of focus in the athletic training literature. However, no theoretical model has been developed to describe the phenomenon and drive investigation.ObjectiveTo better understand the lived experience of the transition to practice and develop a theoretical model of transition to practice for ATs.DesignQualitative study.SettingTelephone interviews.Patients or Other ParticipantsFourteen professional master''s athletic training students (7 men, 7 women, age = 25.6 ± 3.7 years, from 9 higher education institutions) in the first year of clinical practice as newly credentialed ATs.Data Collection and AnalysisParticipants completed semistructured phone interviews at 3 timepoints over 12 to 15 months. The first interview was conducted just before graduation, the second 4 to 6 months later, and the third at 10 to 12 months. The interviews were transcribed and analyzed using a grounded theory approach.ResultsWe developed a theoretical model to explain the causal conditions that triggered transition, how the causal conditions were experienced, the coping strategies used to persist through the first year of practice, and the consequences of those strategies.ConclusionsThe model provides a framework for new athletic training clinicians, educators, and employers to better understand the transition process in order to help new clinicians respond by accepting or adapting to their environment or their behaviors.     

Organization and management of care for military veterans with human immunodeficiency virus/acquired immunodeficiency syndrome in Department of Veterans Affairs Medical Centers

OBJECTIVE: As the largest provider of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome health care services, the Department of Veterans Affairs (VA) has launched a national quality improvement program. As a first step, an assessment of how care for veterans with HIV/acquired immunodeficiency syndrome was organized was conducted. METHODS: Structured surveys were administered to senior HIV clinicians in 118 VA facilities, about local approaches to structuring, staffing, and delivering HIV health services. RESULTS: HIV care was chiefly delivered in special VA-based HIV clinics. HIV-related services were widely available on site, with non-VA referrals being more commonly needed to meet long-term care needs. Urban VA facilities had greater HIV caseloads, were more likely to have separate HIV clinics, and had greater access to HIV expertise, whereas rural practices focused on primary care-based models and tended to rely on off-site VA HIV experts. CONCLUSIONS: Understanding the organization and management of VA-based HIV services will help design systematic quality improvement efforts and meet the treatment needs of HIV-infected veterans.     

Developmental regulation of cytokeratins in cells of the rat mammary gland studied with monoclonal antibodies.

We have isolated two monoclonal antibodies to cytokeratins and determined their cell specificities. They display interesting localization within the rat mammary gland. One (1A10) shows specificity for myoepithelial cells; the other (24B42) is specific for lumenal cells at various stages of development. These two monoclonal antibodies and three others to cytokeratin previously isolated were used in conjunction with antibodies to myosin and collagen IV to confirm and extend our previous findings on epithelial cell types and development within the mammary gland.     

Identification and structural analysis of residues in the V1 region of CD4 involved in interaction with human immunodeficiency virus envelope glycoprotein gp120 and class II major histocompatibility complex molecules.

The human CD4 molecule binds both human immunodeficiency virus envelope protein gp120 and class II major histocompatibility complex (MHC) molecules. We have studied a series of mutants in the region of amino acids 42-49 of CD4 for their ability to bind gp120, to interact with class II MHC, to enhance T-cell activation, and to bind a panel of anti-CD4 antibodies. The mutation Q40P (Gln40----Pro) and the deletion d42-49 were found to disrupt most antibody epitopes in the V1 domain of CD4, suggesting major conformational changes, whereas mutants F43L, G47R, and P48S retained the binding of most of the anti-CD4 antibodies tested. The mutants d42-49, Q40P, F43L, and G47R lost both gp120 and class II MHC binding as well as the ability to enhance T-cell activation. In contrast, the mutation P48S affected neither gp120 binding, nor class II MHC binding, nor T-cell activation. We conclude that within this region the binding sites for gp120 and for class II MHC molecules overlap and that amino acids Phe43 and Gly47 comprise an intimate part of both binding sites. These observations are consistent with a three-dimensional model of the V1 domain of CD4 that was developed in order to understand the structural basis for binding to CD4.     

The transition from caregiving to bereavement: the relationship of care-related strain and adjustment to death

This study examines two competing hypotheses about the relationship between care-related strain and the difficulty adjusting to the impaired relative's death. One hypothesis, and the limited available empirical evidence, suggests that family members who perceive caregiving as stressful will experience some relief when their relative dies because care responsibilities end. An alternative hypothesis, derived from several conceptualizations, posits the opposite relationship, with greater care-related strain predictive of greater strain during bereavement. Panel data from spouse and adult-child caregivers collected before and after the death support the second hypothesis. Respondents who appraise caregiving as more difficult and those who report more negative caregiving consequences for the family assess bereavement as more difficult and report greater bereavement strain for the family.