An Algorithm for the Use of Free Tissue Graft Reconstruction in the Endoscopic Endonasal Approach for Pituitary Tumors.

OBJECTIVE: To identify factors associated with successful use of free tissue grafting versus vascularized reconstruction after resection of pituitary tumors. METHODS: A retrospective chart review of 2 tertiary academic medical centers over 3.5 years was conducted. Variables assessed included age, sex, body mass index, pathology, extent of surgical exposure, cavernous sinus or suprasellar extension, intraoperative cerebrospinal fluid (CSF) leak, grade of leak, previous radiation, and previous surgery. Reconstructive techniques were divided into no reconstruction, free tissue grafts, and vascularized flaps. RESULTS: A total of 485 patients were included. Free grafts were used in 299/485 cases (61.6%) and were more commonly used with smaller approaches (P < 0.001). Larger exposure size and CSF leak grades 2 and 3 were associated with vascularized flap use (P < 0.001 and P = 0.012, respectively). Using multivariate regression, type of reconstruction could be predicted by increasing extent of approach, intraoperative CSF leak grade, and suprasellar extension (odds ratio [OR], 2.014, P < 0.001, 95% confidence interval [CI], 1.335-3.039; OR, 1.636, P = 0.025, 95% CI, 1.064-2.517; OR, 1.975, P < 0.001, 95% CI, 1.554-2.510, respectively). Postoperative CSF leak occurred in 9 of 173 patients (5.2%) with intraoperative leak and was not associated with any factors on analysis. CONCLUSIONS: We propose an algorithm whereby grade 1 CSF leaks in sellar and parasellar resections can be successfully reconstructed with a free graft. Vascularized flaps may be reserved for grade 2 or 3 intraoperative CSF leaks, extended approaches, or tumors with suprasellar extension.

The association of active and passive tobacco smoke exposure with chronic rhinosinusitis symptom severity: A cross-sectional study.

BACKGROUND: Chronic rhinosinusitis (CRS) causes a great deal of morbidity. There are a multitude of causal factors, though their precise contribution to symptom severity has yet to be defined.  We hypothesized that exposure to both primary and secondhand tobacco smoke would correlate with more severe symptoms of CRS. METHODS: This is a prospective cross-sectional study performed at an academic tertiary care medical center from 2010 to 2013. A total of 85 consecutive patients with chronic sinusitis were screened; 70 with medically refractory CRS requiring functional Endoscopic sinus surgery (FESS) were enrolled. Recent tobacco exposure was assessed using serum cotinine levels. Sinonasal mucosa was biopsied to assess ciliary architecture. Demographics, medical history, tobacco and environmental exposures, and computed tomography (CT) imaging were also collected. Two quality of life (QOL) surveys were administered: one disease specific, Sinonasal Outcomes Test-20 (SNOT-20), and one general, Short Form-12 (SF-12). Results were correlated with the aforementioned exposures. RESULTS: The 70 patients had an average age of 46 years, and 42% were male.  Variables that correlated with worse SNOT-20 scores included serum cotinine (r = 0.43, p = 0.002), number of cigarettes smoked daily (r = 0.27, p = 0.03), and number of secondhand cigarettes exposed to per day (r = 0.29, p = 0.04). There were no significant correlations between SNOT-20 scores and Lund-MacKay or axonemal ultrastructural abnormalities (AUA)-ciliary scores. The two five-variable models best predicted disease-specific QOL. CONCLUSIONS: Increased amounts of serum cotinine and primary and secondhand smoke exposure were associated with worse sinonasal QOL. This study establishes an objective relationship between smoke exposure and patient-perceived severity of CRS, emphasizing the importance of tobacco cessation counseling as part of management.

Prion variants and species barriers among Saccharomyces Ure2 proteins.

As hamster scrapie cannot infect mice, due to sequence differences in their PrP proteins, we find "species barriers" to transmission of the [URE3] prion in Saccharomyces cerevisiae among Ure2 proteins of S. cerevisiae, paradoxus, bayanus, cariocanus, and mikatae on the basis of differences among their Ure2p prion domain sequences. The rapid variation of the N-terminal Ure2p prion domains results in protection against the detrimental effects of infection by a prion, just as the PrP residue 129 Met/Val polymorphism may have arisen to protect humans from the effects of cannibalism. Just as spread of bovine spongiform encephalopathy prion variant is less impaired by species barriers than is sheep scrapie, we find that some [URE3] prion variants are infectious to another yeast species while other variants (with the identical amino acid sequence) are not. The species barrier is thus prion variant dependent as in mammals. [URE3] prion variant characteristics are maintained even on passage through the Ure2p of another species. Ure2p of Saccharomyces castelli has an N-terminal Q/N-rich "prion domain" but does not form prions (in S. cerevisiae) and is not infected with [URE3] from Ure2p of other Saccharomyces. This implies that conservation of its prion domain is not for the purpose of forming prions. Indeed the Ure2p prion domain has been shown to be important, though not essential, for the nitrogen catabolism regulatory role of the protein.

ZSCAN4 facilitates chromatin remodeling and promotes the cancer stem cell phenotype.

Cancer stem cells (CSCs) are cells within tumors that maintain the ability to self-renew, drive tumor growth, and contribute to therapeutic resistance and cancer recurrence. In this study, we investigate the role of Zinc finger and SCAN domain containing 4 (ZSCAN4) in human head and neck squamous cell carcinoma (HNSCC). The murine Zscan4 is involved in telomere maintenance and genomic stability of mouse embryonic stem cells. Our data indicate that the human ZSCAN4 is enriched for, marks and is co-expressed with CSC markers in HNSCC. We show that transient ZSCAN4 induction for just 2 days increases CSC frequency both in vitro and in vivo and leads to upregulation of pluripotency and CSC factors. Importantly, we define for the first time the role of ZSCAN4 in altering the epigenetic profile and regulating the chromatin state. Our data show that ZSCAN4 leads to a functional histone 3 hyperacetylation at the promoters of OCT3/4 and NANOG, leading to an upregulation of CSC factors. Consistently, ZSCAN4 depletion leads to downregulation of CSC markers, decreased ability to form tumorspheres and severely affects tumor growth. Our study suggests that ZSCAN4 plays an important role in the maintenance of the CSC phenotype, indicating it is a potential therapeutic target in HNSCC.

DNA polymorphisms in the pepA and PPE18 genes among clinical strains of Mycobacterium tuberculosis: implications for vaccine efficacy.

Tuberculosis continues to be a leading cause of death worldwide. Development of an effective vaccine against Mycobacterium tuberculosis is necessary to reduce the global burden of this disease. Mtb72F, consisting of the protein products of the pepA and PPE18 genes, is the first subunit tuberculosis vaccine to undergo phase I clinical trials. To obtain insight into the ability of Mtb72F to induce an immune response capable of recognizing different strains of M. tuberculosis, we investigated the genomic diversity of the pepA and PPE18 genes among 225 clinical strains of M. tuberculosis from two different geographical locations, Arkansas and Turkey, representing a broad range of genotypes of M. tuberculosis. A combination of single nucleotide polymorphisms (SNPs) and insertion/deletions resulting in amino acid changes in the PPE18 protein occurred in 47 (20.9%) of the 225 study strains, whereas SNPs resulted in amino acid changes in the PepA protein in 14 (6.2%) of the 225 study strains. Of the 122 Arkansas study strains and the 103 Turkey study strains, 32 (26.2%) and 15 (14.6%), respectively, had at least one genetic change leading to an alteration of the amino acid sequence of the PPE18 protein, and many of the changes occurred in regions previously reported to be potential T-cell epitopes. Thus, immunity induced by Mtb72F may not recognize a proportion of M. tuberculosis clinical strains.

A dominant negative mutant beta 2-microglobulin blocks the extracellular folding of a major histocompatibility complex class I heavy chain.

The major histocompatibility complex class I (MHC1) molecule plays a crucial role in cytotoxic lymphocyte function. beta 2-Microglobulin (beta 2m) has been demonstrated to be both a structural component of the MHC1 complex and a chaperone-like molecule for MHC1 folding. beta 2m binding to an isolated alpha 3 domain of MHC1 heavy chain at micromolar concentrations has been shown to accurately model the biochemistry and thermodynamics of beta 2m-driven MHC1 folding. These results suggested a model in which the chaperone-like role of beta 2m is dependent on initial binding to the alpha 3 domain interface of MHC1 with beta 2m. Such a model predicts that a mutant beta 2m molecule with an intact MHC1 alpha 3 domain interaction but a defective MHC1 alpha 1 alpha 2 domain interaction would block beta2m-driven folding of MHC1. In this study we generated such a beta 2m mutant and demonstrated that it blocks MHC1 folding by normal beta 2m at the expected micromolar concentrations. Our data support an initial interaction of beta 2m with the MHC1 alpha 3 domain in MHC1 folding. In addition, the dominant negative mutant beta 2m can block T-cell functional responses to antigenic peptide and MHC1.