Derivation and Initial Validation of the Utility Function for the Hearing Utility Measure (HUM).

OBJECTIVE: The Hearing Utility Measure (HUM) is a replacement hearing attribute for the Health Utilities Index, Mark 3 (HUI-3) designed to improve the responsiveness of utility estimates to changes in hearing-related quality of life. The final development step is to derive the instrument's utility scoring function. METHODS: Residents of Ontario, Canada, aged ≥18 years participated in standard gamble and visual analogue scale exercises. Valuations for levels (response options) within each domain, and for each domain relative to the other domains were elicited and used to generate a hearing utility function. The function outputs hearing utility ranging from 0 = 'unable to hear at all' to 1 = 'perfect hearing' for each of the 25,920 hearing states classifiable by the HUM. Performance was assessed relative to the criterion standard: directly elicited standard gamble utility. Distributions of HUM-derived hearing utility were compared with legacy HUI-3 derived estimates. RESULTS: A total of 126 respondents participated (mean age 39.2, range 18-85 years, 53% female [67/126]). The utility function performed well in the estimation of directly elicited utilities (mean difference 0.03, RMSE 0.06). Using the legacy HUI-3, estimated hearing utility was 1.0 for 118/126 respondents (93.6%) compared with just 66/126 (52.4%) using the HUM. CONCLUSION: The new hearing attribute is capable of measuring variations in hearing utility not captured by the legacy HUI-3, especially near the ceiling of hearing function. These findings justify its application and further work to study its measurement properties in hearing loss populations. LEVEL OF EVIDENCE: 3 Laryngoscope, 2024.

Selective Neurectomy for Postfacial Paralysis Synkinesis: A Systematic Review.

Facial synkinesis is characterized by unintentional contractions of facial musculature secondary to aberrant facial nerve healing. The associated impairment in facial functioning results in a significant decrease in patients' quality of life. The mainstay treatment for postfacial paralysis synkinesis (PFPS) is chemodenervation and physiotherapy, which requires long-term maintenance neurotoxin injections. This can lead to treatment resistance. Selective neurectomy of the distal branches of the facial nerve has been suggested as an effective surgical treatment of PFPS. This study aims to provide a comprehensive systematic review evaluating the efficacy of selective neurectomy for patients presenting with PFPS. Ovid MEDLINE, Ovid Embase, PubMed, Web of Science, and CINAHL were searched from inception until July 2022. Studies that investigated postoperative outcomes of pediatric and/or adult patients who underwent selective neurectomy as a treatment for PFPS were included. The database search identified 1,967 studies, and 11 were ultimately included based on inclusion and exclusion criteria. These 11 studies represented 363 patients. Studies reported on outcomes following selective neurectomy with or without adjuvant therapies for patients with PFPS. The main outcome categories identified were clinician-reported outcomes and patient-reported outcomes. The studies that used clinician-reported outcomes found an improvement in both synkinesis and facial nerve paralysis (FNP) outcomes following selective neurectomy according to their respective grading systems. Three studies looked at patient-reported outcomes and found increased patient-reported quality of life and satisfaction following selective neurectomy. The most reported complications were upper lip contracture, uneven cheek surface, lagophthalmos, and temporary oral incompetence. Selective neurectomy has demonstrated stable or improved synkinesis, FNP, and quality of life outcomes in patients with PFPS. This approach should be considered for patients with PFPS, particularly for patients with refractory symptoms or those who are unable to undergo continued medical management.

Total Synthesis of the Reported Structure of Cahuitamycin A: Insights into an Elusive Natural Product Scaffold.

In a 2016 screen of natural product extracts, a new family of natural products, the cahuitamycins, was discovered and found to inhibit biofilm formation in the human pathogen Acinetobacter baumannii. The proposed molecular structures contained an unusual piperazic acid residue, which piqued interest related to their structure/function and biosynthesis. Herein we disclose the first total synthesis of the proposed structure of cahuitamycin A in a 12-step longest linear sequence and 18% overall yield. Comparison of spectral and biological data of the authentic natural product and synthetic compound revealed inconsistentancies with the isolated metabolite. We therefore executed the diverted total synthesis of three isomeric compounds, which were also found to be disparate from the isolated natural product. This work sets the stage for future synthetic and biochemical investigations of an important class of natural products.

Short Cervix Following Initial Cerclage-Reinforcing Cerclage Versus Expectant Management.

OBJECTIVES: To determine whether reinforcing cerclage following ultrasound evidence of cerclage failure before 24 weeks is an effective method to delay gestational age at delivery, and to decrease the rate of preterm and peri-viable delivery. METHODS: A retrospective review was conducted for all patients who underwent any cervical cerclage procedure at a single tertiary care centre in Toronto, Canada between 1 December 2007 and 31 December 2017. RESULTS: Of 1482 cerclage procedures completed during the study period, 40 pregnant persons who underwent reinforcing cerclage were compared with 40 pregnant persons who were found to have cerclage failure before 24 weeks but were managed expectantly. After adjusting for the shortest cervical length measured prior to 24 weeks, there was no significant difference between the reinforcing cerclage and control group for gestational age at delivery, preterm, or peri-viable birth (P = 0.52, P = 0.54, P = 0.74, respectively). In an unadjusted model, there was a statistically significant increase in placental infection identified on postpartum placenta pathology in the reinforcing cerclage group compared with the expectant management group, 92.9% compared with 66.7% (P = 0.028). CONCLUSION: Reinforcing cerclage is unlikely to successfully delay the gestational age at delivery and reduce rates of preterm and pre-viable birth, especially if irreversible and progressive cervical change has begun. Future work should examine the role of preoperative amniocentesis to explore the impact of pre-existing intra-amniotic infection and reinforcing cerclage success.

The protective role of postoperative radiation therapy in low and intermediate grade major salivary gland malignancies: A study of the Canadian Head and Neck Collaborative Research Initiative.

BACKGROUND: The objective of this study was to examine the utility of postoperative radiation for low and intermediate grade cancers of the parotid and submandibular glands. METHODS: The authors conducted a retrospective, Canadian-led, international, multi-institutional analysis of a patient cohort with low or intermediate grade salivary gland cancer of the parotid or submandibular gland who were treated from 2010 until 2020 with or without postoperative radiation therapy. A multivariable, marginal Cox proportional hazards regression analysis was performed to quantify the association between locoregional recurrence (LRR) and receipt of postoperative radiation therapy while accounting for patient-level factors and the clustering of patients by institution. RESULTS: In total, 621 patients across 14 tertiary care centers were included in the study; of these, 309 patients (49.8%) received postoperative radiation therapy. Tumor histologies included 182 (29.3%) acinic cell carcinomas, 312 (50.2%) mucoepidermoid carcinomas, and 137 (20.5%) other low or intermediate grade primary salivary gland carcinomas. Kaplan-Meier LRR-free survival at 10 years was 89.0% (95% confidence interval [CI], 84.9%-93.3%). In multivariable Cox regression analysis, postoperative radiation therapy was independently associated with a lower hazard of LRR (adjusted hazard ratio, 0.53; 95% CI, 0.29-0.97). The multivariable model estimated that the marginal probability of LRR within 10 years was 15.4% without radiation and 8.8% with radiation. The number needed to treat was 16 patients (95% CI, 14-18 patients). Radiation therapy had no benefit in patients who had early stage, low-grade salivary gland cancer without evidence of nodal disease and negative margins. CONCLUSIONS: Postoperative radiation therapy may reduce LLR in some low and intermediate grade salivary gland cancers with adverse features, but it had no benefit in patients who had early stage, low-grade salivary gland cancer with negative margins.

Health State Utility Values Associated with Cochlear Implants in Adults: A Systematic Review and Network Meta-Analysis.

OBJECTIVES: The cost-effectiveness of bilateral cochlear implants in adults remains uncertain despite established clinical benefits. In cost-effectiveness studies, benefit is often measured by change in health state utility value (HSUV), a single number summary of health-related quality of life anchored at 0 (state of being dead) and 1 (perfect health). Small differences in bilateral cochlear implant HSUV change conclusions of published models, and invalid estimates can therefore mislead policy and funding decisions. As such, we aimed to review and synthesize published HSUV estimates associated with cochlear implants. DESIGN: We included observational or experimental studies reporting HSUV for adult patients (age ≥18 years) with at least moderate-profound sensorineural hearing loss in both ears who received unilateral or bilateral cochlear implants. We searched MEDLINE, EMBASE, PsycINFO, and Cochrane Library databases up to May 1, 2021. Study and participant characteristics and HSUV outcomes were extracted. Narrative synthesis is reported for all studies. A Bayesian network meta-analysis was conducted to generate pooled estimates for the mean difference in HSUV for three comparisons: (1) unilateral cochlear implant versus preimplant, (2) bilateral cochlear implants versus preimplant, (3) bilateral versus unilateral cochlear implants. Our principal measure was pooled mean difference in HSUV. RESULTS: Thirty-six studies reporting unique patient cohorts were identified. Health Utilities Index, 3 (HUI-3) was the most common HSUV elicitation method. HSUV from 19 preimplant mean estimates (1402 patients), 19 unilateral cochlear implant mean estimates (1701 patients), and 5 bilateral cochlear implants mean estimates (83 patients) were pooled to estimate mean differences in HUI-3 HSUV by network meta-analysis. Compared with preimplant, a unilateral cochlear implant was associated with a mean change in HSUV of +0.17 (95% credible interval [CrI] +0.12 to +0.23) and bilateral cochlear implants were associated with a mean change of +0.25 (95% CrI +0.12 to +0.37). No significant difference in HSUV was detected for bilateral compared with unilateral cochlear implants (+0.08 [95% CrI -0.06 to +0.21]). Overall study quality was moderate. CONCLUSIONS: The findings of this review and network meta-analysis comprise the best-available resource for parameterization of cost-utility models of cochlear implantation in adults and highlight the need to critically evaluate the validity of available HSUV instruments for bilateral cochlear implant populations.Protocol registration: PROSPERO (CRD42018091838).

Perceptions of Ontario health system leaders on single-entry models for managing the COVID-19 elective surgery backlog: an interpretive descriptive study.

BACKGROUND: The COVID-19 pandemic has exacerbated pre-existing challenges with respect to access to elective surgery across Canada, and a single-entry model (SEM) approach has been proposed as an equitable and efficient method to help manage the backlog. With Ontario's recent investment in centralized surgical wait-list management, we sought to understand the views of health system leaders on the role of SEMs in managing the elective surgery backlog. METHODS: We used the qualitative method of interpretive description to explore participant perspectives and identify practical strategies for policy-makers, administrators and clinical leaders. We conducted semistructured interviews with health system leaders from across Ontario on Zoom between March and June 2021. We used snowball and purposive sampling. Inclusion criteria included Ontario health care leaders, fluent in English or French, in positions relevant to managing the elective surgery backlog. Exclusion criteria were individuals who work outside Ontario, or do not hold relevant roles. RESULTS: Our interviews with 10 health system leaders - including hospital chief executive officers, surgeons, administrators and policy experts - resulted in 5 emergent domains: perceptions of the backlog, operationalizing and financing SEMs, barriers, facilitators, and equity and patient factors. All participants emphasized the need for clinical leaders to champion SEMs and the utility of SEMs in managing wait-lists for high-volume, low-acuity, low-complexity and low-variation surgeries. INTERPRETATION: Although SEMs are no panacea, the participants in our study stated that they believe SEMs can improve quality and reduce variability in wait times when SEMs are designed to address local needs and are implemented with buy-in from champions. Health care leaders should consider SEMs for improving surgical backlog management in their local jurisdictions.

Longitudinal advocacy training for medical students: a virtual workshop series.

Advocacy curricula in Canadian medical schools vary significantly. Expert-led, interactive workshops can effectively teach students how to address social determinants of health and advocate for patients. The Longitudinal Advocacy Training Series (LATS) is a free-of-charge, virtual program providing advocacy training created for Canadian medical students by students. The program was straightforward to implement and had high participation rates with 1140 participants representing 9.7% of enrolled Canadian medical students. As well, the program had high satisfaction reported by 87.6% of participants. The LATS toolkit enables health professional programs to develop similar programs for empowering effective health advocates.

Au Canada, les programmes de formation en matière de promotion et de défense des droits varient considérablement d'une faculté de médecine à l'autre. Les ateliers interactifs dirigés par des experts constituent un outil efficace pour enseigner aux étudiants la façon aborder les déterminants sociaux de la santé afin de défendre les droits des patients. La Longitudinal Advocacy Training Series (LATS) est un programme virtuel gratuit de formation à la défense des droits, créé par des étudiants pour les étudiants. Le programme, facile à mettre en œuvre, a connu un taux de participation élevé, à savoir 1140 participants représentant 9,7 % des étudiants en médecine au Canada. En outre, 87,6 % des participants se sont dits très satisfaits du programme. La trousse à outils LATS permet aux programmes de formation des professions de la santé de mettre sur pied des modules similaires pour donner aux étudiants les moyens de devenir des défenseurs de la santé efficaces.

Innovation Centers in Health Care Delivery Systems: Structures for Success.

The need to support innovation in health care delivery was prompted by payment reforms and access to digital tools and has been accelerated by the shift to virtual care as part of the COVID-19 pandemic response. Prior to the pandemic, a growing number of health systems set up innovation centers to focus on creating new services and exploring new business models relevant to value-based care. This is distinct from process improvement or implementation science, and often needs a different set of incentives to succeed within a large organization. We used a national survey to identify a diverse sample of innovation centers, and interviewed leaders to describe their aims, organizational structures, and activities. They all aim to improve patient outcomes and experience while reducing costs, but their strategic focus may differ. The centers also vary in their reporting structure, how they build internal capacity, and how they measure success. We highlight the range of strategies through examples of projects that improve quality, reduce costs, and generate new revenue. While the optimal forms and impact of innovation centers are still emerging, the fiscal pressures and the rapid uptake of digital technologies present opportunities for the redesign of health services in the postpandemic era. The experiences of these centers illustrate a set of approaches to increase any organization's capacity for innovation.

Nasal Septal Perforation Reconstruction with Polydioxanone Plate: A Systematic Review.

Nasal septal perforation is an uncommon pathology that is difficult to surgically repair and may significantly impact patients' quality of life. Existing treatments have high complication and failure rates. The use of polydioxanone (PDS) plates to repair septal perforations is an innovative approach that has demonstrated superior outcomes to the conventional techniques. This study aimed to review the literature on PDS plates for nasal septal perforation reconstruction. PubMed, OVID Medline, and OVID Embase databases were searched for relevant articles in June 2021. Search terms included nasal septal perforation, polydioxanone, septal perforation, septal repair, nasal septum, and PDS plate. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were adhered to for this systematic review. Database searches yielded 80 articles. Seven articles were included representing 74 patients. All studies reported the use of PDS plates in addition to other materials. They all reported closure rates of at least 80%. The majority of studies reported no postoperative complications. Nasal septal perforation reconstruction with PDS plates is a promising approach that has demonstrated positive outcomes. Further larger studies are required to evaluate the long-term efficacy of using PDS plates on patients with septal perforations.

Structural and Biochemical Characterization of the Flavin-Dependent Siderophore-Interacting Protein from Acinetobacter baumannii.

Acinetobacter baumannii is an opportunistic pathogen with a high mortality rate due to multi-drug-resistant strains. The synthesis and uptake of the iron-chelating siderophores acinetobactin (Acb) and preacinetobactin (pre-Acb) have been shown to be essential for virulence. Here, we report the kinetic and structural characterization of BauF, a flavin-dependent siderophore-interacting protein (SIP) required for the reduction of Fe(III) bound to Acb/pre-Acb and release of Fe(II). Stopped-flow spectrophotometric studies of the reductive half-reaction show that BauF forms a stable neutral flavin semiquinone intermediate. Reduction with NAD(P)H is very slow (k obs, 0.001 s-1) and commensurate with the rate of reduction by photobleaching, suggesting that NAD(P)H are not the physiological partners of BauF. The reduced BauF was oxidized by Acb-Fe (k obs, 0.02 s-1) and oxazole pre-Acb-Fe (ox-pre-Acb-Fe) (k obs, 0.08 s-1), a rigid analogue of pre-Acb, at a rate 3-11 times faster than that with molecular oxygen alone. The structure of FAD-bound BauF was solved at 2.85 Å and was found to share a similarity to Shewanella SIPs. The biochemical and structural data presented here validate the role of BauF in A. baumannii iron assimilation and provide information important for drug design.

Broad Spectrum Antibiotic Xanthocillin X Effectively Kills Acinetobacter baumannii via Dysregulation of Heme Biosynthesis.

Isonitrile natural products exhibit promising antibacterial activities. However, their mechanism of action (MoA) remains largely unknown. Based on the nanomolar potency of xanthocillin X (Xan) against diverse difficult-to-treat Gram-negative bacteria, including the critical priority pathogen Acinetobacter baumannii, we performed in-depth studies to decipher its MoA. While neither metal binding nor cellular protein targets were detected as relevant for Xan's antibiotic effects, sequencing of resistant strains revealed a conserved mutation in the heme biosynthesis enzyme porphobilinogen synthase (PbgS). This mutation caused impaired enzymatic efficiency indicative of reduced heme production. This discovery led to the validation of an untapped mechanism, by which direct heme sequestration of Xan prevents its binding into cognate enzyme pockets resulting in uncontrolled cofactor biosynthesis, accumulation of porphyrins, and corresponding stress with deleterious effects for bacterial viability. Thus, Xan represents a promising antibiotic displaying activity even against multidrug resistant strains, while exhibiting low toxicity to human cells.

Connecting iron acquisition and biofilm formation in the ESKAPE pathogens as a strategy for combatting antibiotic resistance.

The rise of antibiotic resistant bacteria has become a problem of global concern. Of particular interest are the ESKAPE pathogens, species with high rates of multi-drug resistant infections. Novel antibiotic mechanisms of action are necessary to compliment traditional therapeutics. Recent research has focused on targeting virulence factors as a method of combatting infection without creating selective pressure for resistance or damaging the host commensal microbiome. Some investigations into one such virulence behavior, iron acquisition, have displayed additional effects on another virulence behavior, biofilm formation. The use of exogenous iron-chelators, gallium as an iron mimic, and inhibition of siderophore-mediated iron acquisition are all strategies for disturbing iron-homeostasis that have implicated effects on biofilms. However, the exact nature of this connection remains ambiguous. Herein we summarize these findings and identify opportunities for further investigation.

From General to Specific: Can Pseudomonas Primary Metabolism Be Exploited for Narrow-Spectrum Antibiotics?

The spread of antimicrobial resistance is a major threat to human health, and patients requiring prolonged antibiotic exposure are in desperate need of new therapeutic strategies. It has been hypothesized that tailoring our antibiotics to inhibit molecular targets specific to pathogens might stem the spread of resistance. A prime candidate for such a strategy is Pseudomonas aeruginosa, which can be found in the lungs of nearly all adult cystic fibrosis patients and, due to chronic exposure to antibiotics, has a high rate of multidrug-resistant strains. Although much research has been done on P. aeruginosa virulence factors as narrow-spectrum targets, less attention has been paid to primary carbon metabolism being leveraged for pathogen-specific mechanisms. However, early studies show that primary metabolic pathways, although shared amongst all organisms, contain intricacies specific to Pseudomonas species that have potential for antibiotic exploitation. Here we lay out some of this work in the hopes that it inspires researchers to continue developing a knowledge base for future antibiotic discovery to build upon and include a case study of a Pseudomonas primary metabolic pathway that has been targeted by small molecules in a species-specific manner.

Identification of Specific and Nonspecific Inhibitors of Bacillus anthracis Type†III Pantothenate Kinase (PanK).

Antibiotics with novel mechanisms of action are desperately needed to combat the increasing rates of multidrug-resistant infections. Bacterial pantothenate kinase (PanK) has emerged as a target of interest to cut off the biosynthesis of coenzyme A. Herein we report the results of an in vitro high-throughput screen of over 10 000 small molecules against Bacillus anthracis PanK, as well as a follow-up screen of hits against PanK isolated from Pseudomonas aeruginosa and Burkholderia cenocepacia. Nine hits are structurally categorized and analyzed to set the stage for future drug development.

Crystal Structure of the Siderophore Binding Protein BauB Bound to an Unusual 2:1 Complex Between Acinetobactin and Ferric Iron.

The critical role that iron plays in many biochemical processes has led to an elaborate battle between bacterial pathogens and their hosts to acquire and withhold this critical nutrient. Exploitation of iron nutritional immunity is being increasingly appreciated as a potential antivirulence therapeutic strategy, especially against problematic multidrug resistant Gram-negative pathogens such as Acinetobacter baumannii. To facilitate iron uptake and promote growth, A. baumannii produces a nonribosomally synthesized peptide siderophore called acinetobactin. Acinetobactin is unusual in that it is first biosynthesized in an oxazoline form called preacinetobactin that spontaneously isomerizes to the final isoxazolidinone acinetobactin. Interestingly, both isomers can bind iron and both support growth of A. baumannii. To address how the two isomers chelate their ferric cargo and how the complexes are used by A. baumannii, structural studies were carried out with the ferric acinetobactin complex and its periplasmic siderophore binding protein BauB. Herein, we present the crystal structure of BauB bound to a bis-tridentate (Fe3+L2) siderophore complex. Additionally, we present binding studies that show multiple variants of acinetobactin bind BauB with no apparent change in affinity. These results are consistent with the structural model that depicts few direct polar interactions between BauB and the acinetobactin backbone. This structural and functional characterization of acinetobactin and its requisite binding protein BauB provides insight that could be exploited to target this critical iron acquisition system and provide a novel approach to treat infections caused by this important multidrug resistant pathogen.

Biologically Inspired Total Synthesis of Ulbactin F, an Iron-Binding Natural Product.

Natural products from environmental microbiomes provide exquisite templates for elucidating biological activity in the search for new drugs. A recently discovered marine Brevibacillus sp. metabolite, ulbactin F, was found to inhibit tumor cell migration and invasion at IC50 < 3 µM. Herein, we disclose the first total synthesis of ulbactin F and epi-ulbactin F, which was modeled after the biosynthetic pathway. The scaffold bears structural similarity to siderophores of human pathogens but contains a novel tricyclic ring system derived from cysteine. We have found that ulbactin F forms low-affinity metal complexes, with a preference for Fe3+ and Cu2+, which may hint both at its environmental role and its antimetastatic mechanism of action.

Rigid Oxazole Acinetobactin Analog Blocks Siderophore Cycling in Acinetobacter baumannii.

The emergence of multidrug resistant (MDR) Gram-negative bacterial pathogens has raised global concern. Nontraditional therapeutic strategies, including antivirulence approaches, are gaining traction as a means of applying less selective pressure for resistance in vivo. Here, we show that rigidifying the structure of the siderophore preacinetobactin from MDR Acinetobacter baumannii via oxidation of the phenolate-oxazoline moiety to a phenolate-oxazole results in a potent inhibitor of siderophore transport and imparts a bacteriostatic effect at low micromolar concentrations under infection-like conditions.

Structure-function studies of acinetobactin analogs.

Pathogenic Acinetobacter baumannii excrete the siderophore pre-acinetobactin as an iron-scavenging virulence factor. Pre-acinetobactin is a 2,3-dihydroxy-phenyl oxazoline that undergoes pH-dependent isomerization to the isooxazolidinone form acinetobactin in order to expand the pH range for iron acquisition by A. baumannii. In this study we establish important structure-function relationships for the kinetics of isomerization, iron(iii) binding, and siderophore utilization by A. baumannii. We showed that electronic properties of the phenyl oxazoline influence isomerization kinetics and iron(iii) binding. We found that iron(iii) chelation was directly correlated with A. baumannii utilization. Our studies provide important structural and mechanistic insight for understanding how pathogenic A. baumannii uses pre-acinetobactin as a 2-for-1 iron-scavenging siderophore virulence factor.