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 & Medicine. The organization has 15716 authors who have published 26884 publications receiving 1176697 citations.

Biomaterial and antibiotic strategies for peri-implantitis: a review

Abstract: Dental implants have 89% plus survival rates at 10-15 years, but peri-implantitis or dental implant infections may be as high as 14%. Peri-implantitis can limit clinical success and impose health and financial burdens to patients and health providers. The pathogenic species associated with periodontitis (e.g., Fusobacterium ssp, A. actinomycetemcomitans, P. gingivalis) are also associated with peri-implantitis. Incidence of peri-implantitis is highest within the first 12 months after implantation, and is higher in patients who smoke or have poor oral health as well as with calcium-phosphate-coated or surface-roughened implants. Biomaterial therapies using fibers, gels, and beads to deliver antibiotics have been used in the treatment of Peri-implantitis though clinical efficacy is not well documented. Guided tissue regeneration membranes (e.g., collagen, poly-lactic/glycolic acid, chitosan, ePTFE) loaded with antimicrobials have shown success in reosseointegrating infected implants in animal models but have not been proven in humans. Experimental approaches include the development of anti-bioadhesion coatings, coating surfaces with antimicrobial agents (e.g., vancomycin, Ag, Zn) or antimicrobial releasing coatings (e.g., calcium phosphate, polylactic acid, chitosan). Future strategies include the development of surfaces that become antibacterial in response to infection, and improvements in the permucosal seal. Research is still needed to identify strategies to prevent bacterial attachment and enhance normal cell/tissue attachment to implant surfaces.

Influenza A virus NS2 protein mediates vRNP nuclear export through NES-independent interaction with hCRM1.

Abstract: For nuclear export of proteins, the formation of a ternary export complex composed of the export substrate, a cellular export factor and Ran-GTP is crucial. CRM1 is a cellular export factor for proteins containing leucine-rich nuclear export signals (NESs). Although the NES sequence is crucial for nuclear export, its exact role in the formation of the ternary export complex is controversial. Here we demonstrate an interaction between human CRM1 (hCRM1) and influenza A virus NS2 protein, which contains an NES motif in its N-terminal region. Replacement of the hydrophobic amino acids in the NES motif did not abolish NS2's interaction with hCRM1. Using our recently established systems for the generation of influenza virus or virus-like particles from cloned cDNAs, we found that NS2 is essential for nuclear export of influenza virus ribonucleoprotein (RNP) complexes, and that alteration of the NS2-NES abrogated this event and influenza virus generation. These findings suggest that the NS2-NES is not crucial for the interaction of this protein with hCRM1, but is for the formation of the ternary export complex with Ran-GTP.

Treg cells require the phosphatase PTEN to restrain TH1 and TFH cell responses.

Abstract: The interplay between effector T cells and regulatory T cells (Treg cells) is crucial for adaptive immunity, but how Treg cells control diverse effector responses is elusive. We found that the phosphatase PTEN links Treg cell stability to repression of type 1 helper T cell (TH1 cell) and follicular helper T cell (TFH cell) responses. Depletion of PTEN in Treg cells resulted in excessive TFH cell and germinal center responses and spontaneous inflammatory disease. These defects were considerably blocked by deletion of interferon-γ, indicating coordinated control of TH1 and TFH responses. Mechanistically, PTEN maintained Treg cell stability and metabolic balance between glycolysis and mitochondrial fitness. Moreover, PTEN deficiency upregulates activity of the metabolic checkpoint kinase complex mTORC2 and the serine-threonine kinase Akt, and loss of this activity restores functioning of PTEN-deficient Treg cells. Our studies establish a PTEN-mTORC2 axis that maintains Treg cell stability and coordinates Treg cell-mediated control of effector responses.

The maternal lifestyle study: effects of substance exposure during pregnancy on neurodevelopmental outcome in 1-month-old infants.

Abstract: Objective. This was a prospective longitudinal multisite study of the effects of prenatal cocaine and/or opiate exposure on neurodevelopmental outcome in term and preterm infants at 1 month of age. Methods. The sample included 658 exposed and 730 comparison infants matched on race, gender, and gestational age (11.7% born Results. On the NICU Network Neurobehavioral Scale, cocaine exposure was related to lower arousal, poorer quality of movement and self-regulation, higher excitability, more hypertonia, and more nonoptimal reflexes with most effects maintained after adjustment for covariates. Some effects were associated with heavy cocaine exposure, and effects were also found for opiates, alcohol, marijuana, and birth weight. Acoustic cry characteristics that reflect reactivity, respiratory, and neural control of the cry sound were also compromised by prenatal drug exposure, including cocaine, opiates, alcohol, and marijuana and by birth weight. Fewer cry effects remained after adjustment for covariates. Conclusions. Cocaine effects are subtle and can be detected when studied in the context of polydrug use and level of cocaine exposure. Effects of other drugs even at low thresholds can also be observed in the context of a polydrug model. The ability to detect these drug effects requires a large sample and neurobehavioral tests that are differentially sensitive to drug effects. Long-term follow-up is necessary to determine whether these differences develop into clinically significant deficits.