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Development and validation of a novel LC-MS/MS method for simultaneous quantification of fidaxomicin and metabolite (OP-1118) from feces for gut pharmacobiome studies.

Fidaxomicin is a first-line antibiotic for treating Clostridioides difficile infection. While it has low systemic absorption and reaches high colonic concentrations, it is hydrolyzed to a less active metabolite, OP-1118. Few studies have completely described critical experimental details of liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quantifying fecal fidaxomicin and OP-1118. This study developed and validated a simple, fast, and sensitive LC-MS/MS method to quantify fidaxomicin and OP-1118 in human and mouse feces. This method simplified fecal sample preparation without the use of solid phase extraction and optimized LC-MS/MS parameters. A broad working range (0.3-1000 ng/ml) in both diluted human and murine fecal matrices was achieved with good intra- and inter-day accuracy (93-107%), precision (1-7%), and recovery (70-105%) as well as little IS-normalized matrix effects. This method was utilized to quantify fidaxomicin and OP-1118 in human and murine fecal samples. This novel method was simple, fast, sensitive, and accurate in analyzing fecal fidaxomicin and OP-1118 and could be deployed to facilitate gut pharmacobiome research.

Feces

Identification of elements determining KIR gene demethylation at the CD56-bright stage of NK cell development.

The variegated expression of the KIR family of class I MHC receptors generates specialized natural killer (NK) cells capable of allele-specific HLA recognition. Understanding the mechanism of KIR gene activation will lead to improved methods for the generation of fully functional NK cells. A central RUNX-binding site in the KIR proximal promoter is required for gene activation. RUNX proteins recruit ten-eleven translocation (TET) proteins that generate 5-hydroxymethylcytosine (5hmC) and drive DNA demethylation. Assessment of 5-methylcytosine (5mC) and 5hmC residues at four stages of NK cell development reveals deposition of 5hmC primarily in a CREB site next to the RUNX site at the CD56Bright stage but not the subsequent CD56Dim stage representing fully mature NK cells. KIR promoter demethylation is delayed relative to other lineage-associated genes, indicating a high threshold for KIR gene demethylation in developing NK cells, and a window of opportunity for RUNX/TET-dependent KIR gene activation in CD56Bright NK cells.

6-base sequencing

An Integrated Proteomics and Genomics Approach to Identify Essential Protein Kinases During Human Trophoblast Development.

In the developing human placenta, three subtypes of trophoblast cells, cytotrophoblasts (CTBs), extravillous trophoblasts (EVTs), and syncytiotrophoblasts (STBs), mediate critical functions essential for a successful pregnancy. CTBs constitute the stem/progenitor compartment and differentiate into STBs and EVTs within the floating and anchoring villi, respectively. STBs establish the maternal-fetal exchange interface and secrete human chorionic gonadotropin (hCG), a hormone vital for the maintenance of early pregnancy. EVTs anchor the maternal endometrium and invade the uterine tissue to remodel maternal cells, supporting implantation and progression of pregnancy. In this study, we used human trophoblast stem cells (hTSCs) as a model system and performed quantitative, label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS) to profile the proteome and phosphoproteome in TSC stem state (analogous to undifferentiated CTBs) and following their differentiation to STBs and EVTs. Through a multiomics approach, we integrated our proteomics data with global gene expression profiles to correlate cell-type specific gene and protein expression during human trophoblast development. We also identified global phosphoproteome and analyzed kinases that are specifically active in hTSC stem state, as well as in differentiated STBs and EVTs. We experimentally validated specific kinases, such as BUB1B, PAK6, PKYMT1, and TNIK, that are essential for maintaining the hTSC stem-state. Additionally, atypical protein kinase C isoforms PKCζ are essential for STB development, whereas PTK2B, SRC, TRIO, and LYN are important for EVT development. Our findings highlight key kinases uniquely required for specific stages of trophoblast development during human placentation and suggest that pharmacological inhibition of these kinases could negatively impact the placentation process during pregnancy.

Humans

Oil and gas well development and coccidioidomycosis risk in Kern County, CA, USA: a case-crossover study.

BACKGROUND: Coccidioidomycosis is an emerging fungal disease caused by inhaling Coccidioides spp spores. As spores reside in soil, activities that disturb soil and generate dust can aerosolise and transport the pathogen. The oil and gas industry has been extensively developed in some regions that are endemic for Coccidioides spp and has been associated with dust emissions. Although several adverse health outcomes have previously been associated with oil and gas development, its impact on coccidioidomycosis risk has not been investigated. We aimed to estimate the association between exposure to oil and gas well development (ie, wells in preproduction) and risk of coccidioidomycosis among residents living near new wells. METHODS: In this case-crossover study, we obtained information on reported coccidioidomycosis cases and oil and gas well development between 2007 and 2022 in Kern County, CA, USA. We then compared exposure to preproduction wells within 5 km of each individual's place of residence during both hazard (ie, the 49-139 days before case onset) and control periods using conditional logistic regression. FINDINGS: During the study period, 658 108 (72·4%) of 909 282 of Kern County residents lived within 5 km of at least one preproduction well, and 116 020 (12·8%) lived within 5 km of 23 or more preproduction wells within a single 90-day period. We estimated that the odds of coccidiomycosis incidence were 12·5% (95% CI 5·8-19·6) higher in the 90 days following exposure to at least one preproduction well within 5 km of an individual's place of residence and that the odds of infection increased by 0·7% (0·4-0·9) for each additional preproduction well developed within this distance. INTERPRETATION: These findings support a previously-unrecognised association between the development of oil and gas wells and transmission of coccidioidomycosis, potentially driven by dust generation. Given the prevalence of oil and gas development in the study region, its impact on coccidioidomycosis incidence might be large. FUNDING: National Institutes of Health, National Science Foundation.

Journal Article

Associations Between Paternal Pre-Conceptional Body Mass Index and Lifestyle Factors and Offspring Weight Development.

BACKGROUND: Evidence suggests that pre-conceptional paternal factors, including BMI and diet, may influence offspring development. OBJECTIVES: We examined the associations between paternal BMI, dietary protein intake, glycemic index (GI), smoking and alcohol consumption and offspring development during the first 5 years of life. METHODS: This secondary analysis of an RCT included 162 father-child pairs from pregnancies among women with pre-pregnancy overweight or obesity. Paternal characteristics were reported at gestational week 15, reflecting the preceding 3 months. Offspring anthropometry was measured at birth, 6 and 18 months, 3 and 5 years. Associations were examined using linear mixed models and linear regression models. RESULTS: No consistent associations were found between paternal characteristics and offspring outcomes from birth to 3 years. At age 5, higher paternal BMI was associated with higher offspring BMI z-score (β = 0.07 (CI: 0.03; 0.10)), fat mass index (β = 0.07 kg/m2 (CI: 0.02; 0.12)) and fat-free mass index (β = 0.05 kg/m2 (CI: 0.01; 0.08)). Lower paternal protein intake was associated with higher offspring BMI z-score (β = 0.54 (CI: 0.07; 1.01)) and fat-free mass index (β = 0.60 kg/m2 (CI: 0.13; 1.07)), while moderately higher protein intake was associated with higher waist-to-height ratio (β = 0.03 (CI: 3.00 × 10-3; 0.05)). Higher paternal GI was associated with lower offspring BMI z-score (β = -0.04 (CI: -0.08; -2.14-10-3)) at age 5. Smoking and alcohol were not associated with offspring outcomes. CONCLUSION: Paternal BMI was associated with offspring outcomes at age 5 years, while findings for paternal dietary factors were less consistent.

Humans

Decoding bipotency: a transient regulatory state bridging totipotency and lineage commitment.

Early mammalian embryogenesis entails a coordinated transition from totipotency to the first lineage bifurcation, giving rise to embryonic lineages and the extra-embryonic trophectoderm. The mechanisms by which totipotency is resolved into lineage-primed states remain incompletely understood. Emerging evidence supports a non-binary model in which cells traverse a continuum of potency states, passing through a transient bipotent intermediate that retains both embryonic and extra-embryonic potential while exiting totipotency. Here, we synthesize recent advances in the mechanisms that establish, maintain, and resolve bipotency. We emphasize the coordinated roles of transposable elements, transcription factors, and signaling pathways in regulating this transition. We also highlight newly developed bipotent stem cell models and their implications in generating advanced embryo models in vitro. Notably, current insights are largely derived from mouse systems; given key differences between mouse and human early embryogenesis, extending these findings to human models remains a critical next step.

Animals

The effects of cold temperature on the development, microbiome, and transcriptome of the sea anemone Nematostella vectensis.

Thermal conditions impact essentially all aspects of the physiology for ectotherms. While the effects of high temperatures have been widely studied, cold temperature effects on aquatic invertebrates and their microbial communities have been poorly characterized. To determine the diverse effects of exposure to cold temperatures, we assessed acute and long-term impacts of ecologically relevant low temperatures on the development, microbiome, and gene expression of the sea anemone Nematostella vectensis. Two hours post fertilization, embryos were exposed to temperatures from 4°C to 35°C and development rate to the juvenile stage was quantified. We found temperature impacts the development rate of embryos, where lower temperatures extended development time and resulted in mortality below 10°C. For both microbiome and host transcriptomic responses, anemones were held at 20°C, 10°C, and 0°C and compared at 24 hours and 7 days. Extended exposures to colder temperatures caused restructuring of the host-associated microbiome, with the loss of common taxonomic groups from the class Bacteroidia and Bacilli. Lastly, cold stress induced significant changes in gene expression, which were more pronounced at the 10°C than 0°C but showed little change over time in each temperature. Interestingly, expression of genes associated with innate immunity were among the most differentially expressed genes including heat shock proteins and innate immune genes providing a potential host-imposed mechanism to explain the shift in the microbiome. Overall, cold temperatures have broad effects on many facets of this sea anemone and its microbial community and indicate the importance of cold temperature events when characterizing how ectotherms acclimate to thermal variation.

Animals

Development of a new recombineering system for Edwardsiella species.

Edwardsiella species are important aquaculture pathogens that also cause opportunistic infections in humans, necessitating efficient genome editing tools to study their pathogenesis and develop control strategies. In this study, we identified and characterized six endogenous recombinases pairs from Edwardsiella and its phages. Among these, the BAS_MS17 system exhibited the highest recombination efficiency in E. piscicida EIB202Δp. Extending homology arms from 150 bp to 200 bp improved editing efficiency by 2-fold, while the addition of Redg or Plug further enhanced recombination by 3-fold and 2.5-fold, respectively, without compromising accuracy (100%). More importantly, when applied to E. piscicida sdu12S, Redg or Plug improved the editing efficiency by 8-fold and 7-fold, respectively. Deletion of the phage-derived single-strand binding protein (SSB) reduced efficiency to 25% of the BAS_MS17 level, whereas expression of the endogenous RecA-family SSB (rSSB) increased recombinant yield by 5-fold, highlighting functional conservation. Furthermore, SSB proteins from heterologous hosts failed to enhance recombination efficiency. Using the optimized system, we successfully knocked out ten distinct genes, including virulence-associated loci, with editing accuracy exceeding 85%. Phenotypic analysis revealed that luxR, but not the other tested genes, contributes to biofilm formation. Virulence evaluation results showed that aroA, fur, and hfq are critical virulence-associated factors. Collectively, this streamlined recombineering system provides a simple, rapid, and efficient genetic tool for Edwardsiella, supporting mechanistic studies of virulence and the development of live attenuated vaccine candidates.

Edwardsiella piscicida

Cross-species variant-to-function analyses implicate MEIS1 in conferring sleep abnormalities and impaired cerebellar development.

Genome-wide association studies (GWAS) have identified numerous loci for insomnia, yet functional validation of effector genes remains limited because most risk variants lie in noncoding regions, and the true causal gene is not known. Here, we use prior human cell-based variant-to-gene mapping to nominate six insomnia effector genes and test them in zebrafish, a tractable diurnal vertebrate model well suited for sleep phenotyping. Our CRISPR-based behavioral screening identifies the MEIS1 ortholog, meis1b, as a regulator of sleep maintenance, with crispants displaying impaired nighttime-specific sleep maintenance and increased sleep latency. Comparative chromatin analyses reveal conserved regulatory architecture spanning the human insomnia-associated locus and selectively implicate meis1b, whereas the duplicated ohnolog meis1a was dispensable. Developmental profiling further shows that meis1b is expressed in cerebellar granule progenitors, paralleling human MEIS1 expression, and that its disruption impairs cerebellar development. Together, these findings establish zebrafish as an efficient vertebrate platform for functional interrogation of GWAS candidates and support an evolutionarily conserved cerebellar role for MEIS1 in sleep maintenance.

Animals

Development and Validation of a Predictive Model for Identification of Cognitive Impairment Risk in Older Adults with Subjective Cognitive Decline:A Longitudinal Study.

BACKGROUND: Subjective cognitive decline (SCD) is a transitional state between objective cognitive impairment and cognitively intact mental status, providing a critical window for implementing preventive interventions to delay objective cognitive decline. AIMS: We aimed to develop a predictive model for SCD progression in older adults with mild cognitive impairment (MCI). This model will facilitate the identification of risk factors and establishment of targeted interventions for community-based SCD management. METHODS: Data from the China Health and Retirement Longitudinal Study (CHARLS) was utilized in this study, extracting 18 indicators. Potential predictors selected through univariate Cox regression and LASSO regression analyses were sequentially incorporated into a multivariable Cox regression model. A nomogram was constructed to establish a predictive model. Model validation encompassed Area Under Curve (AUC) metrics for discriminative capacity, complemented by quantitative assessments using calibration curve analysis for precision verification and decision curve analysis (DCA) for clinical utility evaluation. RESULTS: A total of 1099 older adults with SCD were included in the final analysis, of whom 114 (10.3%) developed MCI. Multivariable Cox regression identified residence, marital status, educational level, social participation, gait speed, and baseline cognitive function. The model demonstrated time-dependent AUC values of 0.885, 0.830, 0.839, and 0.836 in the training set when evaluating discriminative capacity at 2-, 4-, 7-, and 9-year, respectively. The predictive model showed excellent predictive ability according to AUC, calibration curve, and DCA. CONCLUSIONS: A predictive model was created to estimate the risk of developing MCI in older individuals with SCD, offering clinician-actionable intervention benchmarks for preventive care.

Humans

Development and validation of an LC-MS/MS method for the quantification of the KRASG12C inhibitor divarasib.

Divarasib is a newly developed covalent KRASG12C inhibitor, currently under clinical investigation in a phase 3 trial in patients with non-small cell lung cancer (NSCLC). At the moment, very limited pharmacokinetic data are publicly known. However, obtaining more insight into the pharmacokinetic properties of divarasib is important, since this may provide a better understanding of its efficacy and safety risks. Pre-clinical studies have been performed in mouse models to evaluate the effect of drug transporters and drug-metabolizing enzymes on the plasma exposure and tissue distribution of divarasib. Therefore, a reliable quantification method is required. To our knowledge, no bioanalytical assay of divarasib has been published yet. Therefore, in this study we developed and validated an assay to quantify divarasib in human plasma and in eight different mouse-related matrices, and partially in mouse plasma, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was initially evaluated over a concentration range of 1-10,000 nM. However, due to carry-over observed at 10,000 nM, the validated calibration range was established at 1-2000 nM, with matrix-dependent LLOQs of 1-10 nM. Erlotinib was used as an internal standard and acetonitrile was utilized to perform protein precipitation as sample pretreatment. Divarasib demonstrated stability in human plasma and in mouse plasma and tissue homogenates under various experimental conditions. A pilot in vivo study showed the applicability of our validated LC-MS/MS method. Ongoing clinical trials may collect plasma samples, and this developed method enables quantification of divarasib in both mouse and human plasma samples.

Animals

Development of the zebrafish foveal analogue: a quantitative atlas of high-acuity zone growth and retinal regionalisation.

The vertebrate retina contains specialised regions for high-acuity vision, exemplified by the human fovea and its zebrafish analogue, the high-acuity zone (HAZ). Despite the widespread use of zebrafish to model retinal disease, a stage-resolved quantitative reference describing normal eye, photoreceptor layer (PRL) and lens growth has been lacking. Here, we apply contrast-enhanced micro-computed tomography (micro-CT) to construct the first three-dimensional micro-CT normative atlas of wild-type zebrafish eye development across five larval stages [3, 5, 7, 10 and 18 days post-fertilisation (dpf)], mapping circumferential PRL thickness, eye and lens morphology, and compartment growth rates. Regional PRL thickening within the temporo-ventral region of the expected HAZ emerged by 5 dpf and was sustained by a localised redistribution of growth, persisting and extending towards the optic nerve through 18 dpf. The PRL, lens and eye grew through four phases, alternating between disproportionate PRL expansion and coordinated growth, while the eye remodelled from a nasal-dominant to a temporo-ventral-dominant form. This regional specialisation was protracted relative to gross ocular growth and could proceed independently of it, paralleling the extended postnatal maturation of the human fovea. This atlas provides a quantitative baseline for distinguishing disease-induced changes from normal variation, supporting zebrafish models of foveal hypoplasia and related disorders.

Animals

A Pilot Study: Developing a Lactating Dairy Goat Model to Study Staphylococcus aureus Mastitis in Women.

INTRODUCTION: Lactational mastitis is common in lactating women, with Staphylococcus aureus as the most commonly isolated agent associated with infectious lactational mastitis. Currently, there are no evidence-based guidelines for antimicrobial treatment due to barriers in obtaining pharmacokinetic data from lactating women. To overcome this barrier, a suitable large animal model is needed. Goats are an ideal translational model for human mastitis due to their anatomical and physiological similarity to humans. The objective of this pilot study was to assess if goats would develop clinical mastitis following intramammary inoculation with a clinical human isolate of S. aureus with the goal of establishing an alternative in vivo model for future research. The hypothesis was that the infected mammary gland half would show similar clinical signs to women with mastitis and demonstrate a similar local immune response when compared to the control mammary gland half. METHODS: One half of the mammary gland of two healthy lactating does was inoculated with a clinical human isolate of S. aureus. The other half of the mammary gland was sham inoculated with sterile buffered saline. Physical examinations, mammary gland assessments, and sterile milk samples were collected every 12 hours post inoculation. At 96 hours post inoculation, the goats were euthanized, and the mammary glands were examined for pathological changes. RESULTS: Goats did not develop systemic signs of disease following inoculation. Focal infected mammary gland changes included warmth, swelling, redness, discoloration, and reduced milk production; the other mammary gland half remained normal throughout the study period. S. aureus was enumerated from only the infected mammary gland half. The microscopic findings of the infected half showed neutrophilic inflammation and cell necrosis consistent with acute mastitis. DISCUSSION: This pilot study demonstrated lactating does can develop clinical signs like those observed in women. Goats have the potential to be a promising animal model to study infectious lactational mastitis.

Animals

Development and protective efficacy of a live attenuated vaccine candidate against goose astrovirus.

Goose astrovirus (GAstV) is a significant pathogen affecting goslings by inducing visceral gout, yet no commercial vaccine is currently available. This study involved the serial passaging of the GAstV-GXNN strain in LMH cells to investigate alterations in viral replication, genomic stability, and pathogenicity, as well as to assess the potential of a vaccine candidate. The findings indicated that the viral titer increased progressively with each passage, reaching 107.35 TCID50/mL by the 120th passage (GAstV-GXNNP120). Whole-genome sequencing revealed the presence of 6, 19, 26, and 28 nucleotide mutations at the 30th, 60th, 90th, and 120th passages, respectively. Pathogenicity assays demonstrated a reduction in virulence with successive passages, culminating in the complete attenuation of GAstV-GXNNP120, which did not induce clinical signs or lesions in one-day-old goslings. Following five successive passages in goslings, the attenuated strain exhibited stable genetic characteristics without any reversion to virulence. Goslings aged one day, inoculated with GAstV-GXNNP120 at dosages ranging from 102.0 to 105.0 TCID50, developed neutralizing antibodies by the third day post-vaccination. Antibody levels increased in a dose-dependent manner, peaking at day 21 and remaining elevated through day 42. Challenge experiments utilizing the virulent GAstV-GXNN strain revealed that groups vaccinated with doses of 103.0 TCID50 and above achieved complete protection. These groups exhibited no clinical symptoms or pathological damage post-challenge, and both tissue viral loads and virus shedding levels were significantly reduced compared to the control group. Consequently, the minimum effective vaccination dose was established at 103.0 TCID50. These results provide a crucial foundation for the development of a live attenuated GAstV vaccine.

Animals

Time to subsequent therapy (TTST) as an endpoint in clinical studies: development of standardized documentation of subsequent therapy through systematic literature review, expert interviews, and Delphi survey.

BACKGROUND: The endpoint Time to Subsequent Therapy (TTST) is an intermediate endpoint used in research and regulatory assessments. TTST denotes initiation of subsequent therapy and is a clearly definable, clinically relevant event for healthcare professionals. However, it has not been systematically established to which extent TTST is subjectively meaningful to patients. The objective of this study was to define TTST as a patient-relevant intermediate endpoint. METHODS: The study examined five oncological indications (breast cancer, prostate cancer, melanoma, multiple myeloma, and non-small cell lung cancer) using a systematic literature review, analysis of case report forms used in international randomized controlled trials, review of German Federal Joint Committee (G-BA) documents, semi-structured interviews and a two-stage Delphi survey with healthcare professionals, patients, and relatives. RESULTS: A total of 35 individuals participated in qualitative interviews. Most of them rated TTST as particularly significant. The Delphi Survey included 264 interviewees in round one, and 117 in round two. Patient-relevance of TTST was confirmed by 81% of respondents (95% confidence interval 76%, 85%). Nine treatment scenarios that justify TTST were identified. To capture patient-relevance, prospective collection of reasons for and consequences of therapy change are required. A checklist with standardized response formats plus free-text fields was developed: a comprehensive master checklist for flexible, complete documentation and a short version focused on therapy change-specific items. CONCLUSIONS: TTST is an intermediate endpoint whose systematic documentation of characteristics demonstrating patient-relevance can be standardized in research and clinical practice using the developed checklists.

Humans

Uncovering parental exposure risks of TCPP: Impaired development and metabolic homeostasis in zebrafish offspring.

As brominated flame retardants are phased out, tris (1‑chloro-2-propyl) phosphate (TCPP), a phosphorus-based flame retardant, has emerged as a prominent detectable flame retardant in the environment. However, TCPP has been found to exhibit endocrine-disrupting effects on organisms, raising significant safety concerns. In our study, we utilized the zebrafish model to explore the toxic effects of parental TCPP exposure on offspring and uncover its regulatory mechanisms through metabolomics analysis. Moreover, the impact on the nervous system and lipid metabolism was examined through behavioral analysis and specific staining. Our findings demonstrated that both embryonic and parental TCPP exposure induced developmental disorders in larvae, along with decreased locomotor activity and disordered lipid metabolism homeostasis. Parental exposure to TCPP, exhibiting stronger developmental toxicity than direct embryonic exposure, notably led to reductions in crucial energy substrates such as amino acids and carbohydrates. Meanwhile, embryonic TCPP exposure primarily affected the endogenous lipid-related metabolites including phospholipids, lipid-soluble vitamins, steroids and fatty acids, promoting lipid accumulation in larval liver and subcutaneous tissue. What's more, continuously parental and embryonic exposure showed the most pronounced effects on zebrafish development and metabolic regulation. Our study highlights the risk posed by parental exposure to TCPP on offspring zebrafish, underscoring the need for comprehensive consideration of the impact from parental exposure in pollutants regulation.

Animals

Rhinoplasty Difficulty Scale: Development and Psychometric Analysis of a Surgeon's Assessment of Rhinoplasty Technique and Nasal Deformity Correction.

BACKGROUND: Rhinoplasty surgeons lack a universal scale of the relative difficulty of rhinoplasty techniques and rhinoplasty deformities. OBJECTIVE: To compare the expert opinion of the difficulty of rhinoplasty techniques and rhinoplasty deformities among international rhinoplasty surgeons, as measured by a scale of difficulty. METHODS: A cross-sectional survey of rhinoplasty surgeons collected training levels, experience, case volume, and perceived expertise. Rhinoplasty techniques/deformities (n = 64) were rated from 1-10, representing the least to most technically demanding. Rasch analysis was used to examine the fit of the observed data to Rasch model requirements, assess rating scale functioning, and provide estimates of internal consistency. RESULTS: Respondents (n = 63) were in practice (<5 years, 14%; 5-10, 20%; 10-20, 20%; 20-30, 26%; >30, 20%), and rhinoplasty volume ranged from <25 (14%) to >100 cases/year (32%). Self-reported expertise was comfortably novice (32%), intermediate (10%), advanced (28%), and expert (30%). Otolaryngology (42%), facial plastic surgery (30%), and plastic surgery (28%) were represented. Rasch estimates of internal consistency reliability were excellent (0.96 for surgeons and 0.99 for items); the item difficulties were more heterogeneous (mean: 0, SD: 1.23) than the distribution of surgeons (mean: -0.09, SD: 0.58). Survey items were ordered by difficulty, ranging from least difficult (inferior turbinate reduction = 1.01) to most difficult (contracted nose repair post-infection = 8.24). CONCLUSION: The newly developed Rhinoplasty Difficulty Scale provides ratings of common rhinoplasty techniques and deformities with a high correlation among experts using this rating scale.

Humans