Frederick A. Matsen

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The human SAMHD1 protein potently restricts lentiviral infection in dendritic cells and monocyte/macrophages but is antagonized by the primate lentiviral protein Vpx, which targets SAMHD1 for degradation. However, only two of eight primate lentivirus lineages encode Vpx, whereas its paralog, Vpr, is conserved across all extant primate lentiviruses. We find(More)
BACKGROUND Bacterial vaginosis (BV) is a common condition that is associated with numerous adverse health outcomes and is characterized by poorly understood changes in the vaginal microbiota. We sought to describe the composition and diversity of the vaginal bacterial biota in women with BV using deep sequencing of the 16S rRNA gene coupled with(More)
Seven cases of total shoulder arthroplasty exhibiting major glenoid radiolucent lines or actual translation of the glenoid component were evaluated to identify factors associated with glenoid loosening. The average time from arthroplasty was 30 months (range, 14-44 months). Six of the patients had severe, incompletely reconstructable rotator cuff tears(More)
BACKGROUND Radiolucent lines about the glenoid component of a total shoulder replacement are a common finding, even on initial postoperative radiographs. The achievement of complete osseous support of the component has been shown to decrease micromotion. We evaluated the ability of a group of experienced shoulder surgeons to achieve complete cementing and(More)
The purpose of this research was to determine the degree to which compression of the humeral head into the glenoid concavity stabilizes it against translating forces. Ten normal fresh-frozen cadaver glenohumeral joints in which the labrum was preserved were used. A compressive load of 50 N was applied to the humeral head in a direction perpendicular to the(More)
It is now common to survey microbial communities by sequencing nucleic acid material extracted in bulk from a given environment. Comparative methods are needed that indicate the extent to which two communities differ given data sets of this type. UniFrac, which gives a somewhat ad hoc phylogenetics-based distance between two communities, is one of the most(More)
The purpose of this study was to characterize the role of the capsule in the interval between the supraspinatus and subscapularis tendons with respect to glenohumeral motion, translation, and stability. We used a six-degrees-of-freedom position-sensor and a six-degrees-of-freedom force and torque-transducer to determine the glenohumoral rotations and(More)
BACKGROUND Propionibacterium acnes has been grown on culture in half of the reported cases of chronic infection associated with shoulder arthroplasty. The presence of this organism can be overlooked because its subtle presentation may not suggest the need for culture or because, in contrast to many orthopaedic infections, multiple tissue samples and weeks(More)
Anterior glenohumeral instability is an important cause of shoulder disability in athletes. Recurrent glenohumeral instability can seriously impair the athlete's performance. Since the surgical repair of recurrent instability may result in a loss of flexibility, particularly in the thrower and gymnast, the physician must optimize both joint stability and(More)
The biomechanics of glenohumeral stability involve several static and dynamic mechanisms to achieve the intricate balance between shoulder mobility and stability. In conjunction with recent in vitro studies, two important stabilizing mechanisms, concavity compression and scapulohumeral balance, were described. Concavity compression refers to the stability(More)