Otolaryngology Applicant Perspectives on In-person and Virtual Residency Interviews.

OBJECTIVE: The objective of this study was to understand applicant perspectives on in-person and virtual otolaryngology residency interviews. STUDY DESIGN: Survey study. SETTING: Otolaryngology residency applicants who were interviewed during 2022-2023. METHODS: Survey sent to all otolaryngology residency applicants who interviewed during the 2022-2023 interview season. RESULTS: A total of 499 applicants were surveyed with 150 responses (30%). Approximately 48.3% of respondents were offered an in-person interview with 78.9% accepting the offer. Of those who did not accept, reasons included not wanting to travel (21.1%) and time conflicts (15.5%). When comparing virtual versus in-person interviews, those who attended virtual interviews were more likely to disagree that they connected with residents (P = .02) and that they had an improved perspective of the program (P = .002). The majority of applicants agreed that virtual interviews are more inclusive and equitable than in-person interviews (70.4%). When asked which interview style applicants would prefer, 63.1% of applicants preferred an in-person interview when compared to virtual with a second look option (29.5%) and virtual (7.4%). Respondents who self-identified as being underrepresented in medicine were less likely to choose in-person as their preferred interview format (P = .01) and were more likely to decline an in-person interview offer due to monetary limitations (P = .04). CONCLUSIONS: Applicants indicated dissatisfaction with connecting with residents and improving their perspective of the program when in a virtual setting. Applicants felt that virtual interviews were more equitable, but that if the barriers to equity were lessened then they would prefer in-person interviews.

Deep neck space infections in end-stage renal disease patients: Prevalence and mortality.

Deep neck space infections (DNSI) are severe infections within the layers of neck fascia that are known to be associated with underlying immunocompromised states. Although uremia associated with kidney disease is known to cause immune system dysfunction, DNSI in patients with kidney disease has been poorly studied. This study investigated the prevalence of DNSI and the associated risk of mortality within the United States end-stage renal disease (ESRD) population, using a retrospective cohort study design and the United States Renal Data System database of patients (ages 18-100) who initiated dialysis therapy between 2005 and 2019. International Classification of Disease-9 and -10 codes were used to identify the diagnosis of DNSI and comorbid conditions. Of the 705,891 included patients, 2.2% had a diagnosis of DNSI. Variables associated with increased risk of DNSI were female sex, black compared to white race, catheter, or graft compared to arteriovenous fistula (AVF) access, autoimmune disease, chronic tonsillitis, diagnoses in the Charlson Comorbidity Index (CCI), tobacco use, and alcohol dependence. DNSI diagnosis was an independent risk factor for mortality, which was also associated with other comorbidity factors such as older age, catheter or graft compared to AVF access, comorbidities in the CCI, tobacco use, and alcohol dependence. Because of the increased mortality risk of DSNI in the ESRD population, health professionals should encourage good oral hygiene practices and smoking cessation, and they should closely monitor these patients to reduce poor outcomes.

Inhibitors of the CD73-adenosinergic checkpoint as promising combinatory agents for conventional and advanced cancer immunotherapy.

The cell surface enzyme CD73 is increasingly appreciated as a pivotal non-redundant immune checkpoint (IC) in addition to PD-1/PD-L1 and CTLA-4. CD73 produces extracellular adenosine (eADO), which not only inhibits antitumor T cell activity via the adenosine receptor (AR) A2AR, but also enhances the immune inhibitory function of cancer-associated fibroblasts and myeloid cells via A2BR. Preclinical studies show that inhibition of the CD73-adenosinergic pathway in experimental models of many solid tumors either as a monotherapy or, more effectively, in combination with PD-1/PD-L1 or CTLA-4 IC blockades, improves antitumor immunity and tumor control. Consequently, approximately 50 ongoing phase I/II clinical trials targeting the CD73-adenosinergic IC are currently listed on https://clinicaltrials.gov. Most of the listed trials employ CD73 inhibitors or anti-CD73 antibodies alone, in combination with A2AR antagonists, and/or with PD-1/PD-L1 blockade. Recent evidence suggests that the distribution of CD73, A2AR and A2BR in tumor microenvironments (TME) is heterogeneous, and this distribution affects CD73-adenosinergic IC function. The new insights have implications for the optimally effective, carefully tailored approaches to therapeutic targeting of this essential IC. In the mini-review, we briefly discuss the cellular and molecular mechanisms of CD73/eADO-mediated immunosuppression during tumor progression and therapy in the spatial context of the TME. We include preclinical data regarding therapeutic CD73-eADO blockade in tumor models as well as available clinical data from completed trials that targeted CD73-adenosinergic IC with or without PD-1/PD-L1 inhibitors and discuss factors that are potentially important for optimal therapeutic outcomes in cancer patients.

Airway Management in Singers: A Cross-sectional Survey.

OBJECTIVE: To review and establish current practices regarding airway management in vocal professionals undergoing surgery. STUDY DESIGN: Cross-sectional survey SETTING: The setting included practitioners that treat vocal professionals across international sub-specialty societies. SUBJECTS AND METHODS: A twenty-one-item survey was sent to practitioners that routinely treat vocal professionals including the American Broncho-Esophagological Association, European Laryngological Society, and 2017 Fall Voice Conference attendees. It included questions regarding the respondents' demographics, preferences for airway control in non-laryngeal and laryngeal surgery, and peri-operative management. RESULTS: Total respondents (n = 163): 82.8% were Laryngologists, 4.3 % were General Otolaryngologists, 3.1% were Head & Neck Oncologists, and 6.8% were Speech-Language Pathologists. One hundred twenty-five of the participants (76.7%) classified their experience with vocal professionals as 'extensive' or 'often.' For non-laryngeal surgery, there was a tendency towards laryngeal mask airway (53.1%) over endotracheal intubation (46.9%). For professional singers, a smaller endotracheal tube was recommended. Size varied based on sex. For males, 88.5% recommended a tube ≤7.0 in non-singers; 98.2% recommended a tube ≤7.0 in singers. In females 76.1% recommended a tube ≤6.0 for non-singers; 94.6 % recommended a size ≤6.0 in a female singer. For laryngeal surgery, 14% of providers personally intubated patients over 90% of the time. Of the providers who work with trainees, 60.5% did not allow resident intubation. CONCLUSION: Objective data regarding precautions in airway management of professional voice users is scarce. This is the largest survey to date on current practices. Survey results indicate that smaller ETTs are preferred for singers, and that more experienced practitioners are preferred for the intubation.

The Feasibility of Utilizing Smartphone Flashlights as an Alternative Endoscopic Light Source in Emergency Situations.

Although the image quality from modern distal chip endoscopes is superior, limited mobility of the endoscopic tower prevents this technology from being used in inpatient and emergency departments. In these settings, otolaryngologists commonly use older flexible laryngoscopes with portable light sources. However, these light sources could malfunction. Smartphones are ubiquitous nowadays, and the smartphone's flashlight may be used alternatively to provide illumination when primary light malfunctions. This study compares the ability of flashlights from various smartphone models in providing adequate illumination for flexible laryngoscopy when compared to a commercially available portable light source. White wall and mucosal images were captured using Olympus P4 flexible scope and lights from the Stryker X8000 endoscopy tower light source, Storz 11301D3 portable light source (control), iPhone 4, iPhone 6, iPhone 8, iPhone X, Galaxy S6, and Galaxy S7. ImageJ was used to quantify pixel intensities with white and black standardized as 250 and 0, respectively. Student 2-tailed t test was used for analysis. The endoscopic tower outperformed all other light sources in all categories. The iPhone 4 and iPhone 6 consistently underperformed in comparison to the Storz 11301D3 portable light source (P < .05). Galaxy S6, Galaxy S7, and newer generation iPhone 8 and iPhone X provide comparable pixel intensities to Storz 11301D3 portable light. Smartphones incorporate different types of light-emitting diodes. Newer Galaxy and iPhone provide adequate illumination for the endoscopic assessment of the airway when compared to commercially available portable light source. However, one should always utilize the best commercially available light source in nonemergent cases.

Occult Metastasis in Laryngeal Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis.

OBJECTIVE: The incidence of occult metastasis (OM) in laryngeal squamous cell carcinoma (SCC) is still widely debated. In this systematic review, we aim to determine the rate of OM in laryngeal SCC, its impact on recurrence, and the role of elective neck dissection (END) in the management of the clinically negative neck. METHODS: A systematic review of the English-language literature in Web of Science, PubMed, MEDLINE, and Cochrane Library databases on occult metastasis in laryngeal SCC from 1977 to 2018 was conducted. Studies evaluating occult metastasis (OM) in patients with laryngeal SCC with clinically negative necks undergoing surgery were included. Studies evaluating other head and neck subsites, clinically node positive, and salvage patients were excluded. RESULTS: Twenty-one articles with a total of 5630 patients were included. The overall rate of OM was 20.5% and was 23% and 12.2% in supraglottic and glottic tumors, respectively. The OM rate in T1-T2 tumors was 13% and 25% in T3-T4 tumors. T3-T4 tumors had significantly greater odds of developing OM compared to T1-T2 tumors (Odds Ratio [OR] = 2.61, 95% Confidence Interval [CI] = 1.92-3.55, P < .00001). Patients with OM were more likely to develop distant metastasis (OR = 5.65, 95% CI = 3.36-9.51, P < .00001). CONCLUSIONS: Patients with advanced T-stage laryngeal SCC should undergo elective neck treatment. More aggressive treatment for patients with history of OM should be considered due to the risk of subsequent regional and distant metastasis. LEVEL OF EVIDENCE: II.

Preoperative Stellate Ganglion Block for Perioperative Pain in Lateralized Head and Neck Cancer: Preliminary Results.

Patients with head and neck cancer represent a vulnerable population at particular risk of opioid dependence due to frequent histories of substance abuse, requirement of extensive surgery, and the synergistic toxicity of multimodal therapy. Regional anesthetic techniques have been used by other surgical disciplines to facilitate early recovery after surgery and decrease postoperative patient narcotic requirements. This pilot study investigates the efficacy of a preoperative regional analgesia using stellate ganglion block in lateralized head and neck cancer surgery. From our early results, stellate ganglion blockade may hold promise as an effective preoperative intervention for controlling early postoperative pain, lessening narcotic requirements, and improving quality of life.

Salivary Clear Cell Carcinoma Clinicopathologic Characteristics and Outcomes: A Population-Based Analysis.

BACKGROUND: Salivary clear cell carcinoma is an uncommon, low-grade malignancy for which limited data describing predictive clinicopathologic factors and treatment outcomes exist because of rarity. METHODS: The authors queried the Surveillance, Epidemiology, and End Results database from 1982 to 2014. Multivariate Cox and Kaplan-Meier analyses were performed to determine disease-specific survival (DSS) and predictive clinicopathologic factors. RESULTS: One hundred ninety-eight patients with salivary clear cell carcinoma were included. Overall incidence was 0.011 per 100 000 individuals, with no significant annual percentage change across years (-0.93%, P = .632). Five-, 10-, and 20-year DSS rates were 81.3% (n = 117), 69.6% (n = 94), and 55.3% (n = 68), respectively. Men (hazard ratio, 4.74; P = .0087) and patients with regional (hazard ratio, 5.59; P = .018) or distant (hazard ratio, 8.9; P = .01) metastases carried a worse prognosis. Five-year DSS was greater in patients with localized disease (96.36%, P < .0001) than those with regional or distant metastases. Treatment with surgery alone had better 10-year DSS (86.3%) compared with treatment with combination radiation and surgery (57.6%) or radiation monotherapy (18.75%, P < .0001). CONCLUSIONS: Salivary clear cell carcinoma carries an overall good prognosis. Patients with localized disease and those treated with surgery alone have more favorable prognoses. Male patients and those with regional or distant metastatic disease at time of presentation carry a worse prognosis. LEVEL OF EVIDENCE: N/A.

Radiation Therapy Impact on Lymph Node Yield in Patients With Laryngeal Squamous Cell Carcinoma.

BACKGROUND: A lymph node yield (LNY) over 20 is considered a quality metric for lateral neck dissection to ensure an oncologic representative sample. Anecdotally, however, LNY in patients undergoing neck dissection after radiation therapy (RT) is lower due to atrophy and fibrosis. OBJECTIVE: To determine whether preoperative RT decreases LNY in patients with laryngeal cancers undergoing surgery. METHODS: Medical record database was queried for patients presenting between 2006 and 2015 with laryngeal cancer. Tabulation was made for location (glottic/supraglottic), stage, and side for the total number of lymph nodes between primary surgery and RT (salvage surgery) groups. Descriptive analysis and a paired Student t test were used for statistical analysis. RESULTS: Fifty-nine patients were included in the study for a total of 98 neck dissections. Twenty-six (44%) patients had primary surgery, and 33 (56%) patients had salvage surgery. The mean left and right total LNY in the salvage surgery group was 27.6 and 29.5, respectively, and 32.2 and 33.7 for the primary surgery group. A difference of 4.5 (left) and 4.3 (right) in LNY between the salvage surgery and primary surgery group was found. A Student t test showed no statistically significant difference in LNY between both groups when analyzed per site (glottic and supraglottic), side, and stage (III-IV). CONCLUSION: Although patients with prior RT had a lower mean of LNY, our results did not demonstrate a statistically significant difference. Further studies with a larger number of patients are recommended.

Workup of Suspected Chest Metastases on 18F-FDG-PET/CT in Head and Neck Cancer: Worth the Wait?

The objective of our study is to assess the impact of equivocal or positive positron emission tomography combined with low-dose noncontrast computed tomography (PET/CT) findings in the chest on treatment for head and neck cancer (HNC). We reviewed charts of patients presented at Augusta University's Head and Neck Tumor Board (AUTB) between 2013 and 2016 with the following exclusion criteria: <18 years, Veterans Affairs patients, those with incomplete data, and those without a history of head and neck squamous cell carcinoma. The lung/thorax sections of the radiologists' PET/CT reports were graded as "Positive, Equivocal, or Negative" for chest metastases. Patients who underwent workup for suspected chest metastases were assessed for treatment delays, changes in treatment plans, and complications. In addition, we evaluated the time between AUTB presentation and peri-treatment PET/CT to primary treatment initiation were calculated between groups. There was a total of 363 patients with PET/CT prior to treatment, the read was "Negative" in 71.3% (n = 259), "Equivocal" in 20.9% (n = 76), and "Positive" in 5.8% (n = 21). Of 272 patients with complete treatment data, 22 underwent workup for suspected chest metastases. Mean time from PET/CT to treatment initiation was 27.5 days without workup and 64.9 days with workup ( P < .0001), and from AUTB presentation was 29.1 days without workup and 62.5 days with workup ( P < .0001). Five (19.2%) patients experienced a complication from workup. Twenty (76.9%) patients had no changes in their treatment plan after workup. In conclusion, our results for potential chest metastases on PET/CT in patients with HNC are often not clear-cut. Workup of suspected chest metastasis based on PET/CT findings significantly delays primary treatment initiation and may cause serious complications.

Heterogeneity of the Head and Neck Squamous Cell Carcinoma Immune Landscape and Its Impact on Immunotherapy.

Head and neck squamous cell carcinomas (HNSCCs) are highly aggressive, multi-factorial tumors in the upper aerodigestive tract affecting more than half a million patients worldwide each year. Alcohol, tobacco, and human papillomavirus (HPV) infection are well known causative factors for HNSCCs. Current treatment options for HNSCCs are surgery, radiotherapy, chemotherapy, or combinatorial remedies. Over the past decade, despite the marked improvement in clinical outcome of many tumor types, the overall 5-year survival rate of HNSCCs remained ∼40-50% largely due to poor availability of effective therapeutic options for HNSCC patients with recurrent disease. Therefore, there is an urgent and unmet need for the identification of specific molecular signatures that better predict the clinical outcomes and markers that serve as better therapeutic targets. With recent technological advances in genomic and epigenetic analyses, our knowledge of HNSCC molecular characteristics and classification has been greatly enriched. Clinical and genomic meta-analysis of multicohort HNSCC gene expression profile has clearly demonstrated that HPV+ and HPV- HNSCCs are not only derived from tissues of different anatomical regions, but also present with different mutation profiles, molecular characteristics, immune landscapes, and clinical prognosis. Here, we briefly review our current understanding of the biology, molecular profile, and immunological landscape of the HPV+ and HPV- HNSCCs with an emphasis on the diversity and heterogeneity of HNSCC clinicopathology and therapeutic responses. After a review of recent advances and specific challenges for effective immunotherapy of HNSCCs, we then conclude with a discussion on the need to further enhance our understanding of the unique characteristics of HNSCC heterogeneity and the plasticity of immune landscape. Increased knowledge regarding the immunological characteristics of HPV+ and HPV- HNSCCs would improve therapeutic targeting and immunotherapy strategies for different subtypes of HNSCCs.

TP53 mutation status divides myelodysplastic syndromes with complex karyotypes into distinct prognostic subgroups.

Risk stratification is critical in the care of patients with myelodysplastic syndromes (MDS). Approximately 10% have a complex karyotype (CK), defined as more than two cytogenetic abnormalities, which is a highly adverse prognostic marker. However, CK-MDS can carry a wide range of chromosomal abnormalities and somatic mutations. To refine risk stratification of CK-MDS patients, we examined data from 359 CK-MDS patients shared by the International Working Group for MDS. Mutations were underrepresented with the exception of TP53 mutations, identified in 55% of patients. TP53 mutated patients had even fewer co-mutated genes but were enriched for the del(5q) chromosomal abnormality (p < 0.005), monosomal karyotype (p < 0.001), and high complexity, defined as more than 4 cytogenetic abnormalities (p < 0.001). Monosomal karyotype, high complexity, and TP53 mutation were individually associated with shorter overall survival, but monosomal status was not significant in a multivariable model. Multivariable survival modeling identified severe anemia (hemoglobin < 8.0 g/dL), NRAS mutation, SF3B1 mutation, TP53 mutation, elevated blast percentage (>10%), abnormal 3q, abnormal 9, and monosomy 7 as having the greatest survival risk. The poor risk associated with CK-MDS is driven by its association with prognostically adverse TP53 mutations and can be refined by considering clinical and karyotype features.

Head and Neck Cancer Soft Tissue Radiation Necrosis-Diagnostic Challenge.

A 53-year-old man with T4aN2cM0 tongue base squamous cell carcinoma received definitive chemoradiation. FDG PET/CT at 6 weeks showed partial metabolic response with soft tissue air indicating radiation necrosis at primary site and complete response in the neck. At 9 weeks, contrasted CT showed worsening but nonenhancing ulceration, area biopsied demonstrating a minute carcinoma focus with treatment effect. At 12 weeks, PET/CT showed increased primary site uptake interpreted as disease progression; however, no viable tumor was found at salvage surgery. Because nonenhancing ulceration predicts pure radiation necrosis with no viable tumor, contrasted CT may guide treatment selection in challenging cases.

Fascia Lata Free Flap Anastomosed to the Superior Trochlear System for Reconstruction of the Anterior Skull Base.

Objectives This study aims to introduce a novel technique for the reconstruction of the anterior skull base using a free vascularized anterolateral thigh fascia lata free flap (FLFF) anastomosed to the superior trochlear artery (STA). Methods The diameter of the STA was measured in 38 (76 sides) computed tomography angiographies (CTAs). Independently, six cadaver heads were used to measure the diameter of the supratrochlear system, and the model was applied to one of them. Results In women, the average diameter of the STA was 2.5 and 2.8 mm 2 for the right and left sides, respectively; for men, it was 3.0 and 3.2 mm 2 , respectively. In cadavers, the average diameter of both STA was 2.5 mm 2 . There was no statistical difference when comparing the right and left STA diameters between the CTA from women and men ( p < 0.208 and < 0.492, respectively). An FLFF advanced through the nose was anastomosed to the STA to reconstruct the anterior skull base. Conclusion The STA is a constant vessel with a 2.5 to 3.0 mm 2 diameter in men and women that can be used as a recipient free flap vessel. The FLFF can cover the entire skull base. This is a novel method to reconstruct the anterior skull base when local flaps are not available.

Telomere length is an independent prognostic marker in MDS but not in de novo AML.

Telomere dysfunction is implicated in the generation of large-scale genomic rearrangements that drive progression to malignancy. In this study we used high-resolution single telomere length analysis (STELA) to examine the potential role of telomere dysfunction in 80 myelodysplastic syndrome (MDS) and 95 de novo acute myeloid leukaemia (AML) patients. Despite the MDS cohort being older, they had significantly longer telomeres than the AML cohort (P < 0·0001) where telomere length was also significantly shorter in younger AML patients (age <60 years) (P = 0·02) and in FLT3 internal tandem duplication-mutated AML patients (P = 0·03). Using a previously determined telomere length threshold for telomere dysfunction (3·81 kb) did not provide prognostic resolution in AML [Hazard ratio (HR) = 0·68, P = 0·2]. In contrast, the same length threshold was highly prognostic for overall survival in the MDS cohort (HR = 5·0, P < 0·0001). Furthermore, this telomere length threshold was an independent parameter in multivariate analysis when adjusted for age, gender, cytogenetic risk group, number of cytopenias and International Prognostic Scoring System (IPSS) score (HR = 2·27, P < 0·0001). Therefore, telomere length should be assessed in a larger prospective study to confirm its prognostic role in MDS with a view to integrating this variable into a revised IPSS.

Early lipofuscin accumulation in frontal lobe epilepsy.

OBJECTIVE: This study reports on a novel brain pathology in young patients with frontal lobe epilepsy (FLE) that is distinct from focal cortical dysplasia (FCD). METHODS: Surgical specimens from 20 young adults with FLE (mean age, 30 years) were investigated with histological/immunohistochemical markers for cortical laminar architecture, mammalian target of (mTOR) pathway activation and inhibition, cellular autophagy, and synaptic vesicle-mediated trafficking as well as proteomics analysis. Findings were correlated with pre-/postoperative clinical, imaging, and electrophysiological data. RESULTS: Excessive lipofuscin accumulation was observed in abnormal dysmorphic neurones in 6 cases, but not in seven FCD type IIB and 7 pathology-negative cases, despite similar age and seizure histories. Abnormal dysmorphic neurones on proteomics analysis were comparable to aged human brains. The mTOR pathway was activated, as in cases with dysplasia, but the immunoreactivities of nucleoporin p62, DEP-domain containing protein 5, clathrin, and dynamin-1 were different between groups, suggesting that enhanced autophagy flux and abnormal synaptic vesicle trafficking contribute to early lipofuscin aggregation in these cases, compared to suppression of autophagy in cases with typical dysplasia. Cases with abnormal neuronal lipofuscin showed subtle magnetic resonance imaging cortical abnormalities that localized with seizure onset zone and were more likely to have a family history. INTERPRETATION: We propose that excess neuronal lipofuscin accumulation in young patients with FLE represents a novel pathology underlying this epilepsy; the early accumulation of lipofuscin may be disease driven, secondary to as-yet unidentified drivers accelerating autophagic pathways, which may underpin the neuronal dysfunction in this condition. Ann Neurol 2016;80:882-895.

Impact of socioeconomic status on disease phenotype, genomic landscape and outcomes in myelodysplastic syndromes.

Genetic and epigenetic alterations contribute to the biological and clinical characteristics of myelodysplastic syndromes (MDS), but a role for socioeconomic environment remains unclear. Here, socioeconomic status (SES) for 283 MDS patients was estimated using the Scottish Index of Multiple Deprivation tool. Indices were assigned to quintile categorical indicators ranked from SES1 (lowest) to SES5 (highest). Clinicopathological features and outcomes between SES quintiles containing 15%, 20%, 19%, 30% and 16% of patients were compared. Prognostic scores identified lower-risk MDS in 82% of patients, with higher-risk disease in 18%. SES quintiles did not associate with age, gender, cytogenetics, International Prognostic scores or, in sub-analysis (n = 95), driver mutations. The odds ratio of a diagnosis of refractory anaemia was greater than other MDS sub-types in SES5 (OR 1·9, P = 0·024). Most patients (91%) exclusively received supportive care. SES did not associate with leukaemic transformation or cause of death. Cox regression models confirmed male gender (P < 0·05), disease-risk (P < 0·0001) and age (P < 0·01) as independent predictors of leukaemia-free survival, with leukaemic transformation an additional determinant of overall survival (P = 0·07). Thus, if access to healthcare is equitable, SES does not determine disease biology or survival in MDS patients receiving supportive treatment; additional studies are required to determine whether outcomes following disease-modifying therapies are influenced by SES.

A study of phenylalanine side-chain dynamics in surface-adsorbed peptides using solid-state deuterium NMR and rotamer library statistics.

Extracellular matrix proteins adsorbed onto mineral surfaces exist in a unique environment where the structure and dynamics of the protein can be altered profoundly. To further elucidate how the mineral surface impacts molecular properties, we perform a comparative study of the dynamics of nonpolar side chains within the mineral-recognition domain of the biomineralization protein salivary statherin adsorbed onto its native hydroxyapatite (HAP) mineral surface versus the dynamics displayed by the native protein in the hydrated solid state. Specifically, the dynamics of phenylalanine side chains (viz., F7 and F14) located in the surface-adsorbed 15-amino acid HAP-recognition fragment (SN15: DpSpSEEKFLRRIGRFG) are studied using deuterium magic angle spinning ((2)H MAS) line shape and spin-lattice relaxation measurements. (2)H NMR MAS spectra and T1 relaxation times obtained from the deuterated phenylalanine side chains in free and HAP-adsorbed SN15 are fitted to models where the side chains are assumed to exchange between rotameric states and where the exchange rates and a priori rotameric state populations are varied iteratively. In condensed proteins, phenylalanine side-chain dynamics are dominated by 180° flips of the phenyl ring, i.e., the "π flip". However, for both F7 and F14, the number of exchanging side-chain rotameric states increases in the HAP-bound complex relative to the unbound solid sample, indicating that increased dynamic freedom accompanies introduction of the protein into the biofilm state. The observed rotameric exchange dynamics in the HAP-bound complex are on the order of 5-6 × 10(6) s(-1), as determined from the deuterium MAS line shapes. The dynamics in the HAP-bound complex are also shown to have some solution-like behavioral characteristics, with some interesting deviations from rotameric library statistics.

Clinical and biological implications of driver mutations in myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a heterogeneous group of chronic hematological malignancies characterized by dysplasia, ineffective hematopoiesis and a variable risk of progression to acute myeloid leukemia. Sequencing of MDS genomes has identified mutations in genes implicated in RNA splicing, DNA modification, chromatin regulation, and cell signaling. We sequenced 111 genes across 738 patients with MDS or closely related neoplasms (including chronic myelomonocytic leukemia and MDS-myeloproliferative neoplasms) to explore the role of acquired mutations in MDS biology and clinical phenotype. Seventy-eight percent of patients had 1 or more oncogenic mutations. We identify complex patterns of pairwise association between genes, indicative of epistatic interactions involving components of the spliceosome machinery and epigenetic modifiers. Coupled with inferences on subclonal mutations, these data suggest a hypothesis of genetic "predestination," in which early driver mutations, typically affecting genes involved in RNA splicing, dictate future trajectories of disease evolution with distinct clinical phenotypes. Driver mutations had equivalent prognostic significance, whether clonal or subclonal, and leukemia-free survival deteriorated steadily as numbers of driver mutations increased. Thus, analysis of oncogenic mutations in large, well-characterized cohorts of patients illustrates the interconnections between the cancer genome and disease biology, with considerable potential for clinical application.

Dysregulation of autophagy in chronic lymphocytic leukemia with the small-molecule Sirtuin inhibitor Tenovin-6.

Tenovin-6 (Tnv-6) is a bioactive small molecule with anti-neoplastic activity. Inhibition of the Sirtuin class of protein deacetylases with activation of p53 function is associated with the pro-apoptotic effects of Tnv-6 in many tumors. Here, we demonstrate that in chronic lymphocytic leukemia (CLL) cells, Tnv-6 causes non-genotoxic cytotoxicity, without adversely affecting human clonogenic hematopoietic progenitors in vitro, or murine hematopoiesis. Mechanistically, exposure of CLL cells to Tnv-6 did not induce cellular apoptosis or p53-pathway activity. Transcriptomic profiling identified a gene program influenced by Tnv-6 that included autophagy-lysosomal pathway genes. The dysregulation of autophagy was confirmed by changes in cellular ultrastructure and increases in the autophagy-regulatory proteins LC3 (LC3-II) and p62/Sequestosome. Adding bafilomycin-A1, an autophagy inhibitor to Tnv-6 containing cultures did not cause synergistic accumulation of LC3-II, suggesting inhibition of late-stage autophagy by Tnv-6. Thus, in CLL, the cytotoxic effects of Tnv-6 result from dysregulation of protective autophagy pathways.