Laryngeal Anatomy, Molecular Biology, Cause, and Risk Factors for Laryngeal Cancer

Laryngeal cancer is declining in incidence in many parts of the world, as smoking becomes a less common habit. However, challenging cases of laryngeal cancer still exist and require expertise from otolaryngologists. This article reviews the relevant anatomy and lymphatic drainage pathways of the larynx because they pertain to cancer spread. The molecular and immune landscapes of laryngeal cancer, which are tightly linked to smoking, are also discussed.

Quantifying and Improving the Performance of Speech Recognition Systems on Dysphonic Speech

OBJECTIVE

This study seeks to quantify how current speech recognition systems perform on dysphonic input and if they can be improved.

STUDY DESIGN

Experimental machine learning methods based on a retrospective database.

SETTING

Single academic voice center.

METHODS

A database of dysphonic speech recordings was created and tested against 3 speech recognition platforms. Platform performance on dysphonic voice input was compared to platform performance on normal voice input. A custom speech recognition model was trained on voice from patients with spasmodic dysphonia or vocal cord paralysis. Custom model performance was compared to base model performance.

RESULTS

All platforms performed well on normal voice, and 2 platforms performed significantly worse on dysphonic speech. Accuracy metrics on dysphonic speech returned values of 84.55%, 88.57%, and 93.56% for International Business Machines (IBM) Watson, Amazon Transcribe, and Microsoft Azure, respectively. The secondary analysis demonstrated that the lower performance of IBM Watson and Amazon Transcribe was driven by performance on spasmodic dysphonia and vocal fold paralysis. Thus, a custom model was built to increase the accuracy of these pathologies on the Microsoft platform. Overall, the performance of the custom model on dysphonic voices was 96.43% and on normal voices was 97.62%.

CONCLUSION

Current speech recognition systems generally perform worse on dysphonic speech than on normal speech. We theorize that poor performance is a consequence of a lack of dysphonic voices in each platform's original training dataset. We address this limitation with transfer learning used to increase the performance of these systems on all dysphonic speech.

Defining the Performance of Clinician's Ability to Screen for Laryngeal Mass From Voice

OBJECTIVE

Defining a clinician's ability to perceptually identify mass from voice will inform the feasibility, design priorities, and performance standards for tools developed to screen for laryngeal mass from voice. This study defined clinician ability of and examined the impact of expertise on screening for laryngeal mass from voice.

STUDY DESIGN

Task comparison study between experts and nonexperts rating voices for the probability of a laryngeal mass.

SETTING

Online, remote.

METHODS

Experts (voice-focused speech-language pathologists and otolaryngologists) and nonexperts (general medicine providers) rated 5-s/i/voice samples (with pathology defined by laryngoscopy) for the probability of laryngeal mass via an online survey. The intraclass correlation coefficient (ICC) estimated interrater and intrarater reliability. Diagnostic performance metrics were calculated. A linear mixed effects model examined the impact of expertise and pathology on ratings.

RESULTS

Forty clinicians (21 experts and 19 nonexperts) evaluated 344 voice samples. Experts outperformed nonexperts, with a higher area under the curve (70% vs 61%), sensitivity (49% vs 36%), and specificity (83% vs 77%) (all comparisons p < .05). Interrater reliability was fair for experts and poor for nonexperts (ICC: 0.48 vs 0.34), while intrarater reliability was excellent and good, respectively (ICC: 0.9 and 0.6). The main effects of expertise and underlying pathology were significant in the linear model (p < .001).

CONCLUSION

Clinicians demonstrate inadequate performance screening for laryngeal mass from voice to use auditory perception for dysphonia triage. Experts' superior performance indicates that there is acoustic information in a voice that may be utilized to detect laryngeal mass based on voice.

Defining Biochemical Cure After Low Dose Rate Prostate Brachytherapy: External Validation of 4-year Prostate-specific Antigen Nadir as a Predictor of 10- and 15-year Disease-free Survival

AIMS

To externally validate a proposed biochemical definition of cure following low dose rate (LDR) brachytherapy for prostate cancer - 4-year post-implant prostate-specific antigen (PSA) ≤0.2 ng/ml - in a UK population, and report the long-term (10- and 15-year) outcomes for patients stratified by National Comprehensive Cancer Network (NCCN) risk groups, through analysis of a large, prospectively collected, single-centre database.

MATERIALS AND METHODS

All patients treated with LDR brachytherapy for prostate cancer at a single UK centre between 2001 and November 2020 (n = 1142) were eligible; 632 patients met the inclusion criteria for the analysis. The primary end point was disease-free survival (DFS), defined as freedom from clinical, radiological or PSA progression requiring androgen deprivation therapy. Four-year PSA was categorised as ≤0.2, >0.2 to ≤0.5, >0.5 to ≤1.0 and >1.0 ng/ml. Kaplan-Meier analysis to 15 years was undertaken for each group, and sensitivity and specificity of 4-year PSA as a surrogate for long-term cure were calculated. Kaplan-Meier analysis to 15 years was repeated, stratifying patients by NCCN risk groups.

RESULTS

The median cohort age was 63 years; the median follow-up was 9.1 years (range 3.5-18.7). In total, 248 patients were available for analysis at year 10, 46 at year 15. Sixty-four patients (10.1%) relapsed during the study period. The 10-year DFS for 4-year PSA categories ≤0.2, >0.2 to ≤0.5, >0.5 to ≤1.0 and >1.0 ng/ml (95% confidence intervals) were 97.5% (95.4-99.6), 89.0% (82.4-96.1), 81.5% (70.5-94.2) and 41.8% (29.7-58.9), respectively. The 10-year DFS results for NCCN low, favourable-intermediate and unfavourable-intermediate risk disease were 93.1% (89.6-96.7), 92.1% (87.6-96.9) and 75.9% (67.8-84.9), respectively.

CONCLUSIONS

Patients with 4-year PSA ≤0.2 ng/ml may be considered cured, and could be discharged to general practitioner follow-up. LDR brachytherapy is an excellent treatment option for patients with low and favourable-intermediate risk prostate cancer, but those with unfavourable-intermediate risk disease should be considered for treatment intensification strategies.

Native State Volume Fluctuations in Proteins as a Mechanism for Dynamic Allostery

Allostery enables tight regulation of protein function in the cellular environment. Although existing models of allostery are firmly rooted in the current structure-function paradigm, the mechanistic basis for allostery in the absence of structural change remains unclear. In this study, we show that a typical globular protein is able to undergo significant changes in volume under native conditions while exhibiting no additional changes in protein structure. These native state volume fluctuations were found to correlate with changes in internal motions that were previously recognized as a source of allosteric entropy. This finding offers a novel mechanistic basis for allostery in the absence of canonical structural change. The unexpected observation that function can be derived from expanded, low density protein states has broad implications for our understanding of allostery and suggests that the general concept of the native state be expanded to allow for more variable physical dimensions with looser packing.

The Importance of Prostate-specific Antigen (PSA) Nadir and Early Identification of PSA Relapse after 10 Years of Prostate Iodine 125 Seed Brachytherapy in Edinburgh

AIMS

To analyse our 5 and 10 year prostate brachytherapy outcome data and to assess the impact of PSA nadir on relapse free survival and whether an alternative definition of PSA relapse could detect men destined to fail by the Phoenix definition at an earlier time point.

MATERIALS AND METHODS

474 men were treated over a 10 year period between 20012 and 2011 and divided into 2 five year cohorts for the purpose of the analysis.

RESULTS

The risk of relapse is strongly predicted by post treat prostate-specific antigen (PSA) nadir. After 3 years post-treatment, PSA nadir plus 0.4 ng/ml identified men at risk of relapse 17 months earlier than the Phoenix definition.

CONCLUSION

The Phoenix definition of nadir plus 2.0 ng/ml does not allow the early identification of men destined to relapse. The initiation of salavage therapy at the earliest opportunity could potentially affect subsequent survival and an outline randomised controlled trial proposal is presented.

Conservation of side-chain dynamics within a protein family

The question of protein dynamics and its relevance to function is currently a topic of great interest. Proteins are particularly dynamic at the side-chain level on the time scale of picoseconds to nanoseconds. Here, we present a comparison of NMR-monitored side-chain motion between three PDZ domains of approximately 30% sequence identity and show that the side-chain dynamics display nontrivial conservation. Methyl (2)H relaxation was carried out to determine side-chain order parameters (S(2)), which were found to be more similar than naively expected from sequence, local packing, or a combination of the two. Thus, the dynamics of a rather distant homologue appears to be an excellent predictor of a protein's side-chain dynamics and, on average, better than current structure-based methods. Fast side-chain dynamics therefore display a high level of organization associated with global fold. Beyond simple conservation, the analysis herein suggests that the pattern of side-chain flexibility has significant contributions from nonlocal elements of the PDZ fold, such as correlated motions, and that the conserved dynamics may directly support function.

Improving Outcomes for Limited Stage Small Cell Lung Cancer Patients in Scotland with Concomitant Chemoradiation

AIMS

To determine whether the introduction of early concomitant chemoradiotherapy for patients with limited stage small cell lung cancer (LS-SCLC) has resulted in acceptable outcomes and toxicity in a UK practice.

MATERIALS AND METHODS

The case records of all patients with LS-SCLC treated with chemoradiotherapy from July 2001 to 2004 were reviewed, and subjected to descriptive statistics and proportional hazards analysis.

RESULTS

Concomitant chemoradiotherapy was delivered to 30 patients and sequential chemoradiotherapy was delivered to 36 patients. The former patients tended to be younger (mean 58.9 vs 64.1 years, P=0.01); the latter patients tended to have bulkier disease. There was no difference in performance status, but cisplatin was given more often in the former group (90% vs 44%, P<0.0001). Grade 3 acute oesophagitis occurred in less than 10% of either group and there were no cases of grade 3 or greater pneumonitis. Two-year actuarial survival for the concomitant group was 53% (95% confidence interval 36-71%) and 36% (95% confidence interval 20-52%) for the sequential group (P=0.018). Proportional hazards analysis showed an increased hazard of death with increasing performance status and age, sequential therapy and the use of cisplatin with sequential therapy.

CONCLUSION

Concomitant chemoradiotherapy can be safely given in a UK population with outcomes comparable with those reported in North American series.

CspA regulates pigment production in Staphylococcus aureus through a SigB-dependent mechanism

We report that the cold shock protein CspA of Staphylococcus aureus is required for maximal production of pigment. Results from transcriptional studies revealed that loss of CspA resulted in decreased expression of genes needed for the biosynthesis of 4,4'-diaponeurosporene and the alternative sigma factor SigB.

Delivery of antimicrobials into parasites

To eliminate apicomplexan parasites, inhibitory compounds must cross host cell, parasitophorous vacuole, and parasite membranes and cyst walls, making delivery challenging. Here, we show that short oligomers of arginine enter Toxoplasma gondii tachyzoites and encysted bradyzoites. Triclosan, which inhibits enoyl-ACP reductase (ENR), conjugated to arginine oligomers enters extracellular tachyzoites, host cells, tachyzoites inside parasitophorous vacuoles within host cells, extracellular bradyzoites, and bradyzoites within cysts. We identify, clone, and sequence T. gondii enr and produce and characterize enzymatically active, recombinant ENR. This enzyme has the requisite amino acids to bind triclosan. Triclosan released after conjugation to octaarginine via a readily hydrolyzable ester linkage inhibits ENR activity, tachyzoites in vitro, and tachyzoites in mice. Delivery of an inhibitor to a microorganism via conjugation to octaarginine provides an approach to transporting antimicrobials and other small molecules to sequestered parasites, a model system to characterize transport across multiple membrane barriers and structures, a widely applicable paradigm for treatment of active and encysted apicomplexan and other infections, and a generic proof of principle for a mechanism of medicine delivery.

Effect of volume recruitment on response to surfactant treatment in rabbits with lung injury

We determined if surfactant treatment effect can be enhanced by mechanical volume recruitment during surfactant administration by measuring functional residual capacity, tidal volume, the alveolar portion of tidal volume, dynamic compliance of the respiratory system, a/A ratio, and PaCO2 by measuring before and after surfactant administration to rabbits with lung injury induced by airway lavage. There was improvement in all lung function indices when surfactant was given with volume recruitment, but when surfactant was given without volume recruitment, the only index to show significant improvement was a/A ratio of oxygenation. These results support the hypothesis that mechanical recruitment of terminal airspaces from a previously unventilated compartment will enhance the effectiveness of surfactant replacement by facilitating the distribution of instilled surfactant to this compartment.

Validation of a nitrogen washout system to measure functional residual capacity in premature infants with hyaline membrane disease

A multiple-breath nitrogen washout system designed to measure lung volume in mechanically ventilated infants was validated by assessing three performance criteria: 1) accuracy of lung volume measurements in the presence of an endotracheal tube leak was assessed by comparing the measurements of functional residual capacity (FRC) in a mechanical lung model with and without airway leak; 2) in vivo accuracy was assessed in rabbits by comparing FRC measurements obtained by this system with measurements obtained by helium dilution; and 3) in vivo precision was assessed by analyzing measurements of FRC obtained in replicate measurements at different times in ventilator-dependent premature infants with hyaline membrane disease. The average difference between the measurements of FRC in a mechanical lung model with airway leak and without leak was 3.0 +/- 9.4% (mean +/- SD, P > 0.2), and no difference was greater than 20%. There was a significant correlation between the measurements of FRC in rabbits by nitrogen washout and by helium dilution (r = 0.93, P < 0.0001), and 65.4% of the paired measurements were within 20% of their average. The 95% limits of agreement within pairs of measurements by the two techniques ranged from -4.0 to + 6.5 mL/kg. FRC measured by helium dilution was slightly higher (1.3 +/- 2.7 mL/kg, P < 0.01) than FRC measured by nitrogen washout, and positive end-expiratory pressure was a significant predictor of this difference (P < 0.0001). The regression between the individual FRC measurements obtained in premature infants and the average of the other replicates was significant (r2 > 0.98, P < 0.0001). The coefficient of variation was 12.3%. These findings provide further validation of this multiple-breath nitrogen washout system for measuring FRC in premature infants during mechanical ventilation.

Effects of morphine and pancuronium on lung volume and oxygenation in premature infants with hyaline membrane disease

To determine the effect of analgesia and paralysis on lung volume and oxygenation in premature infants supported by mechanical ventilation because of hyaline membrane disease, functional residual capacity (FRC), and arterial/alveolar oxygen tension ratio were measured in nine premature infants with hyaline membrane disease before and after the administration of morphine sulfate and pancuronium bromide. Without a change of positive end-expiratory pressure, ventilator rate and peak inspiratory pressure were increased before the first set of measurements to minimize the contribution of the infants' own respiratory effort to total ventilation. These ventilator settings were then held constant (except fraction of inspired oxygen) before and after the administration of the drugs. The FRC was measured with a multiple-breath N2 washout technique by means of whole-body plethysmography to measure airway flow. The FRC and the ratio of arterial to alveolar oxygen tension decreased in seven of nine patients after treatment with morphine and pancuronium. The decrease in FRC for all patients was significant (2.4 +/- 2.9 ml/kg; p < 0.05), and a significant correlation was demonstrated between the change in the arterial/alveolar oxygen tension ratio and the change in FRC (r = 0.82; p < 0.01). Gestational age, birth weight, postnatal age, severity of lung disease, and time after the administration of morphine and pancuronium were not significantly correlated with the change in FRC. We believe that a decrease in oxygenation caused by alveolar derecruitment occurred even though the ventilator settings had been increased before the first set of measurements. The decrease in FRC in these infants, who are thought to have alveolar instability because of surfactant deficiency, may have resulted from the loss of expiratory braking mechanisms. We conclude that analgesia and paralysis should be used with caution under these circumstances.

The physiologic effects of surfactant treatment on gas exchange in newborn premature infants with hyaline membrane disease

To describe the physiologic effects of surfactant treatment on gas exchange in human premature infants with hyaline membrane disease, functional residual capacity (FRC), tidal volume (VT), the alveolar portion of tidal volume (VA), alveolar ventilation (VA), nitrogen clearance index, effective breath fraction calculated as VA/VT, compliance of the respiratory system, and arterial oxygen and carbon dioxide tensions were measured in 17 patients before and 0.5, 2, and 6 h after the administration of a single dose of either a synthetic surfactant (SS), Exosurf (n = 10), or a bovine surfactant (BS), Survanta (n = 7). By 2 h, treatment with either BS or SS was followed by an increase in the arterial/alveolar ratio of PO2 (a/A) and in FRC (p < 0.01 for both a/A and FRC). The a/A and FRC improved sooner (p < 0.001) and to a greater extent (p < 0.01) after BS than after SS. Compliance of the respiratory system and VT were decreased after either BS or SS at 0.5 h (p < 0.01) and remained decreased after SS at 2 h (p < 0.01). There was no significant change in VA or VA after either BS or SS. Because FRC and a/A increased without an accompanying increase in VA, VA, or compliance of the respiratory system, we believe that the immediate increase in FRC in this study was caused by stabilization of gas exchange units already being ventilated in addition to recruitment of new units.(ABSTRACT TRUNCATED AT 250 WORDS)