University of Tennessee Health Science Center

About: University of Tennessee Health Science Center is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Transplantation. The organization has 15716 authors who have published 26884 publications receiving 1176697 citations.

A High-Resolution Single Nucleotide Polymorphism Genetic Map of the Mouse Genome

Abstract: High-resolution genetic maps are required for mapping complex traits and for the study of recombination. We report the highest density genetic map yet created for any organism, except humans. Using more than 10,000 single nucleotide polymorphisms evenly spaced across the mouse genome, we have constructed genetic maps for both outbred and inbred mice, and separately for males and females. Recombination rates are highly correlated in outbred and inbred mice, but show relatively low correlation between males and females. Differences between male and female recombination maps and the sequence features associated with recombination are strikingly similar to those observed in humans. Genetic maps are available from http://gscan.well.ox.ac.uk/#genetic_map and as supporting information to this publication.

Improved Success in Nonoperative Management of Blunt Splenic Injuries: Embolization of Splenic Artery Pseudoaneurysms

Abstract: Objectives: By using abdominal computed tomographic scans in the evaluation of blunt splenic trauma, we previously identified the presence of vascular blush as a predictor of failure, with a failure of nonoperative management of 13% in that series. This finding led to an alteration in our management scheme, which now includes the aggressive identification and embolization of splenic artery pseudoaneurysms. Methods: The medical records of 524 consecutive patients with blunt splenic injury managed over a 4.5-year period were reviewed for the following information: age, Injury Severity Score (ISS), American Association for the Surgery of Trauma splenic injury grade (SIG), method and outcome of management. Results: Of the patients, 66% were male with a mean age of 32± 16, and mean ISS of 25 ± 13. A total of 180 patients (34%) were managed with urgent operation on admission (81% splenectomy (SIG 4.0), 19% splenorrhaphy (SIG 2.6)). The remaining 344 patients (66%) were hemodynamically stable and underwent computed tomographic scan and planned nonoperative management. Of these patients, 322 patients (94%) were successfully managed nonoperatively (61% of total splenic injuries). In 26 patients (8%), a contrast blush identified on computed tomographic scan was confirmed as a parenchymal pseudoaneurysm on arteriography. Twenty patients (SIG, 2.8) were successfully embolized. In six patients, technical failure precluded embolization; all required splenectomy (SIG, 4.0). A total of 22 patients (6%) failed nonoperative management, including the six with unsuccessful embolization attempts. Sixteen patients (SIG, 3.0) who had no evidence of pseudoaneurysm were explored for a falling hematocrit, hemodynamic instability, or a worsening follow-up computed tomography: 13 patients had splenectomy, and three patients had splenorrhaphy. Conclusions: Aggressive surveillance for and embolization of posttraumatic splenic artery pseudoaneurysms improved the rate of successful nonoperative management of blunt splenic trauma to 61%, with a nonoperative failure rate of only 6%. In comparison with our previous work, this reduction in failure of nonoperative management is a significant improvement (p < 0.03).

Latent Murine γ-Herpesvirus Infection Is Established in Activated B Cells, Dendritic Cells, and Macrophages

Abstract: Intranasal infection of mice with the murine γ-herpesvirus MHV-68 results in an acute lytic infection in the lung, followed by the establishment of lifelong latency. Development of an infectious mononucleosis-like syndrome correlates with the establishment of latency and is characterized by splenomegaly and the appearance of activated CD8+ T cells in the peripheral blood. Interestingly, a large population of activated CD8+ T cells in the peripheral blood expresses the Vβ4+ element in their TCR. In this report we show that MHV-68 latency in the spleen after intranasal infection is harbored in three APC types: B cells, macrophages, and dendritic cells. Surprisingly, since latency has not previously been described in dendritic cells, these cells harbored the highest frequency of latent virus. Among B cells, latency was preferentially associated with activated B cells expressing the phenotype of germinal center B cells, thus formally linking the previously reported association of latency gene expression and germinal centers to germinal center B cells. Germinal center formation, however, was not required for the establishment of latency. Significantly, although three cell types were latently infected, the ability to stimulate Vβ4+CD8+ T cell hybridomas was limited to latently infected, activated B cells.

Enhanced expression of the developmentally regulated extracellular matrix molecule tenascin following adult brain injury

Abstract: Tenascin is an extracellular matrix molecule synthesized and released by young astrocytes during embryonic and early postnatal development of the nervous system, and it is concentrated in boundaries around emerging functional neuronal units. In the adult nervous system, tenascin can be detected only in very low levels. Distinct spatial and temporal distributions of tenascin during developmental events suggest a role in the guidance and/or segregation of neurons and their processes within incipient functional patterns. We show here, using in situ hybridization and immunocytochemistry, that stab wounds of the adult mouse cerebellar and cerebral cortices result in an enhanced expression of tenascin in a discrete region around the lesion site that is associated with a subset of glial fibrillary acidic protein-positive astrocytes. Tenascin up-regulation in the lesioned adult brain may be directly involved in failed regeneration or indirectly involved through its interactions with other glycoconjugates that either inhibit or facilitate neurite growth.

Staged Management of Giant Abdominal Wall Defects: Acute and Long-Term Results

Abstract: Fluid resuscitation from hemorrhagic and septic shock results in significant soft tissue edema. The bowel is not spared, and this visceral edema often precludes abdominal wall closure after celiotomy because the fascia cannot be approximated without excessive tension. Closure under tension often leads to fascial necrosis or abdominal compartment syndrome. Recognition of those complications has led to a widespread application of leaving the abdominal cavity open after either primary surgery or after decompressive laparotomy for established compartment syndrome. A wide variety of techniques have been applied for management of the resulting acute defect, whereas a paucity of information has been reported concerning definitive management of the large ventral hernias, which result when the abdomen has been managed in an open fashion after a catastrophic shock insult. Polypropylene mesh has been used for temporary closure but has been associated with infection, mesh extrusion, and fistula. Intestinal fistulization remains the most morbid complication associated with the acute management of the open abdomen. Fistula rates of 12-50% have been reported when prostheses are used for acute management.1-3 Other methods of maintaining the viscera in the abdominal cavity during the initial phase have included acute coverage with intravenous solution bags, closure with zipper or Velcro-type devices sewn to the fascial edges, and vacuum dressing approaches.4-7 We reported an initial experience with a staged approach to management of these defects a decade ago after experiences with acute coverage using most of the aforementioned materials.1 Over time, we began to steadily adopt absorbable mesh for acute management, which ultimately became our acute prosthesis of choice. When prosthetic materials are subsequently used for definitive abdominal wall reconstruction, the most important complications are prosthetic infection and recurrent hernia. Although gram-positive infections occasionally occur in association with permanent mesh used for reconstruction, many infections result when mesh is inserted in the face of intestinal contamination from either associated ostomy closure or fistula excision, which are commonly associated with management of the initial insult. Recurrent hernia rates of 15-50% have been reported with the use of polypropylene mesh for definitive reconstruction of large abdominal wall defects.1,8 We reported a small number of definitive reconstructions using local tissue transfer without permanent prostheses to avoid the complication of infected foreign body, and in attempt to reduce recurrent hernia rates.1 Since that time, we have added modifications to the acute management of the open abdominal wall defects and have also developed a sizable experience with definitive reconstruction using a modified components separation reconstruction technique. That technique uses local myofascial tissue transfer and usually avoids the need for permanent prosthetic material for hernia repair. The present study was performed to analyze results of both acute and long-term management including definitive reconstruction with this staged approach.