Binding promiscuity of therapeutic factor VIII.

The binding promiscuity of proteins defines their ability to indiscriminately bind multiple unrelated molecules. Binding promiscuity is implicated, at least in part, in the off-target reactivity, non-specific biodistribution, immunogenicity and/or short half-life of potentially efficacious protein drugs, thus affecting their clinical use. In this review, we discuss the current evidence for the binding promiscuity of factor VIII (FVIII), a protein used for the treatment of hemophilia A, which cumulates poor pharmacokinetics, and elevated immunogenicity. We summarize the different canonical and non-canonical molecular interactions that FVIII may establish in the circulation and that could be responsible for its therapeutic liabilities. We also provide information suggesting that the FVIII light chain, and notably its C1 and C2 domains, could play an important role in binding promiscuity. We believe that the knowledge accumulated over years of FVIII usage could be exploited for the development of tools that predict drug efficacy and toxicity and open a mutational space to reduce the binding promiscuity of newly generated protein drugs while conserving their therapeutic efficacy.

Clock gene homologs lin-42 and kin-20 regulate circadian rhythms in C. elegans.

Circadian rhythms are endogenous oscillations in nearly all organisms, from prokaryotes to humans, allowing them to adapt to cyclical environments for close to 24 h. Circadian rhythms are regulated by a central clock, based on a transcription-translation feedback loop. One important protein in the central loop in metazoan clocks is PERIOD, which is regulated in part by Casein kinase 1ε/δ (CK1ε/δ) phosphorylation. In the nematode Caenorhabditis elegans, period and casein kinase 1ε/δ are conserved as lin-42 and kin-20, respectively. Here, we studied the involvement of lin-42 and kin-20 in the circadian rhythms of the adult nematode using a bioluminescence-based circadian transcriptional reporter. We show that mutations of lin-42 and kin-20 generate a significantly longer endogenous period, suggesting a role for both genes in the nematode circadian clock, as in other organisms. These phenotypes can be partially rescued by overexpression of either gene under their native promoter. Both proteins are expressed in neurons and epidermal seam cells, as well as in other cells. Depletion of LIN-42 and KIN-20, specifically in neuronal cells after development, was sufficient to lengthen the period of oscillating sur-5 expression. Therefore, we conclude that LIN-42 and KIN-20 are critical regulators of the adult nematode circadian clock through neuronal cells.

Structural basis for inhibition of coagulation factor VIII reveals a shared antigenic hotspot on the C1 domain.

BACKGROUND: Hemophilia A arises from dysfunctional or deficient coagulation factor (F)VIII and leads to inefficient fibrin clot formation and uncontrolled bleeding events. The development of antibody inhibitors is a clinical complication in hemophilia A patients receiving FVIII replacement therapy. LE2E9 is an anti-C1 domain inhibitor previously isolated from a mild/moderate hemophilia A patient and disrupts FVIII interactions with von Willebrand factor and FIXa, though the intermolecular contacts that underpin LE2E9-mediated FVIII neutralization are undefined. OBJECTIVES: To determine the structure of the complex between FVIII and LE2E9 and characterize its mechanism of inhibition. METHODS: FVIII was bound to the antigen binding fragment (Fab) of NB2E9, a recombinant construct of LE2E9, and its structure was determined by cryogenic electron microscopy. RESULTS: This report communicates the 3.46 Å structure of FVIII bound to NB2E9, with its epitope comprising FVIII residues S2040 to Y2043, K2065 to W2070, and R2150 to H2155. Structural analysis reveals that the LE2E9 epitope overlaps with portions of the epitope for 2A9, a murine-derived inhibitor, suggesting that these residues represent a shared antigenic region on the C1 domain between FVIII-/- mice and hemophilia A patients. Furthermore, the FVIII:NB2E9 structure elucidates the orientation of the LE2E9 glycan, illustrating how the glycan sterically blocks interactions between the FVIII C1 domain and the von Willebrand factor D' domain. A putative model of the FVIIIa:FIXa complex suggests potential clashing between the NB2E9 glycan and FIXa light chain. CONCLUSION: These results describe an antigenic "hotspot" on the FVIII C1 domain and provide a structural basis for engineering FVIII replacement therapeutics with reduced antigenicity.

SEMA3: A free smartphone platform for daily life surveys.

Traditionally, behavioral, social, and health science researchers have relied on global/retrospective survey methods administered cross-sectionally (i.e., on a single occasion) or longitudinally (i.e., on several occasions separated by weeks, months, or years). More recently, social and health scientists have added daily life survey methods (also known as intensive longitudinal methods or ambulatory assessment) to their toolkit. These methods (e.g., daily diaries, experience sampling, ecological momentary assessment) involve dense repeated assessments in everyday settings. To facilitate research using daily life survey methods, we present SEMA3 ( http://www.SEMA3.com ), a platform for designing and administering intensive longitudinal daily life surveys via Android and iOS smartphones. SEMA3 fills an important gap by providing researchers with a free, intuitive, and flexible platform with basic and advanced functionality. In this article, we describe SEMA3's development history and system architecture, provide an overview of how to design a study using SEMA3 and outline its key features, and discuss the platform's limitations and propose directions for future development of SEMA3.

Exploring the Relationships Between Body Image, Sexual Well-Being, and Community Connectedness among Gay, Bisexual and Queer+ Men.

Sexual minority (SM) men are more likely than heterosexual men to experience body dissatisfaction due to prevailing body ideals (e.g. lean and muscular) within the SM community. Negative body image can have harmful effects on well-being, and, by extension, sexual well-being. The current study aimed to investigate whether SM men's minority identification and LGBTQ+ community connectedness moderates the relationship between drives for muscularity and sexual anxiety. To address this aim, 298 Australian-residing SM men completed an online survey that examined drive for muscularity, sexual anxiety, and connectedness or identification with the LGBTQ+ and SM-specific communities. As hypothesized, the results showed a positive relationship between drive for muscularity and sexual anxiety. Additionally, LGBTQ+ community connectedness, but importantly not SM identification, was found to moderate this relationship, showing a positive association only when connection was at low or average levels. These results highlight the beneficial effects that LGBTQ+ community connection can have for SM men, such as protecting them against the harmful impacts of poor body image on sexual well-being. These results also provide preliminary insights into the need to expand the understandings of bodily diversity, and diversity of sexual well-being experiences, among SM men less connected to the broader LGBTQ+ community.

Neighborhood racial income inequality and cognitive health.

INTRODUCTION: Neighborhood socioeconomic status (SES) has been linked to dementia, but the distribution of SES within a neighborhood may also matter. METHODS: Data from 460 (47% Black, 46% White) older adults from the Michigan Cognitive Aging Project were linked to census tract-level data from the National Neighborhood Data Archive (NaNDA). Neighborhood SES included two composites reflecting disadvantage and affluence. Neighborhood racial income inequality was the ratio of median incomes for White versus Black residents. Generalized estimating equations examined associations between neighborhood factors and cognitive domains. RESULTS: Neighborhood racial income inequality was uniquely associated with worse cognitive health, and these associations did not differ by participant race. Neighborhood disadvantage was only associated with worse cognitive health among Black participants. DISCUSSION: Both the level and racial distribution of SES within a neighborhood may be relevant for dementia risk. Racial differences in the level and impact of neighborhood SES contribute to dementia inequalities. HIGHLIGHTS: Black participants lived in neighborhoods with lower socioeconomic status (SES) than White participants, on average. Neighborhood SES and racial income inequality were associated with worse cognition. Effects of neighborhood racial income inequality did not differ across racial groups. Effects of neighborhood SES were only evident among Black participants.

"We're one small piece of the puzzle": evaluating the impact of short-term funding for tier two weight management services.

Introduction: Overweight and obesity are a global health epidemic and many attempts have been made to address the rising prevalence. In March 2021 the UK government announced £100 million of additional funding for weight management provisions. Of this, £30.5 million was split across local authorities in England to support the expansion of tier two behavioural weight management services for adults. The present work aimed to explore how this funding was used within the Yorkshire and Humber region to consolidate learning, collate best practice, and provide recommendations for future funding use. Method: One-hour semi-structured interviews were conducted with 11 weight management service commissioners representing 9 of the 15 local authorities in the region. Interviews were recorded, transcribed and analysed using an established health inequality framework. From this, recommendations were co-developed with the commissioner group to establish best practice for future funding use. Results: Commissioners recognised that targeted weight management services were only one small piece of the puzzle for effectively managing obesity. Therefore, recommendations include targeting underserved communities, focussing on early prevention, addressing weight management in a whole systems context, and embracing innovative and holistic approaches to weight management. Discussion: Current short-term funding and restrictive commissioning processes of tier two services prevents sustainable and innovative weight management practice which is detrimental to patients, falls short of addressing health inequalities and negatively impacts staff health and wellbeing.

The enteroendocrine axis and its effect on gastrointestinal function, nutrition, and inflammation.

PURPOSE OF REVIEW: Gastrointestinal (GI) dysfunction limits enteral nutrition (EN) delivery in critical illness and contributes to systemic inflammation. The enteroendocrine (EE) axis plays an integral role in this interface between nutrition, inflammation, and GI function in critical illness. In this review, we present an overview of the EE system with a focus on its role in GI inflammation and function. RECENT FINDINGS: Enteroendocrine cells have been primarily described in their role in macronutrient digestion and absorption. Recent research has expanded on the diverse functions of EE cells including their ability to sense microbial peptides and metabolites and regulate immune function and inflammation. Therefore, EE cells may be both affected by and contribute to many pathophysiologic states and interventions of critical illness such as dysbiosis , inflammation, and alternative EN strategies. In this review, we present an overview of EE cells including their growing role in nonnutrient functions and integrate this understanding into relevant aspects of critical illness with a focus on EN. SUMMARY: The EE system is key in maintaining GI homeostasis in critical illness, and how it is impacted and contributes to outcomes in the setting of dysbiosis , inflammation and different feeding strategies in critical illness should be considered.

Natural language processing pipeline to extract prostate cancer-related information from clinical notes.

OBJECTIVES: To develop an automated pipeline for extracting prostate cancer-related information from clinical notes. MATERIALS AND METHODS: This retrospective study included 23,225 patients who underwent prostate MRI between 2017 and 2022. Cancer risk factors (family history of cancer and digital rectal exam findings), pre-MRI prostate pathology, and treatment history of prostate cancer were extracted from free-text clinical notes in English as binary or multi-class classification tasks. Any sentence containing pre-defined keywords was extracted from clinical notes within one year before the MRI. After manually creating sentence-level datasets with ground truth, Bidirectional Encoder Representations from Transformers (BERT)-based sentence-level models were fine-tuned using the extracted sentence as input and the category as output. The patient-level output was determined by compilation of multiple sentence-level outputs using tree-based models. Sentence-level classification performance was evaluated using the area under the receiver operating characteristic curve (AUC) on 15% of the sentence-level dataset (sentence-level test set). The patient-level classification performance was evaluated on the patient-level test set created by radiologists by reviewing the clinical notes of 603 patients. Accuracy and sensitivity were compared between the pipeline and radiologists. RESULTS: Sentence-level AUCs were ≥ 0.94. The pipeline showed higher patient-level sensitivity for extracting cancer risk factors (e.g., family history of prostate cancer, 96.5% vs. 77.9%, p < 0.001), but lower accuracy in classifying pre-MRI prostate pathology (92.5% vs. 95.9%, p = 0.002) and treatment history of prostate cancer (95.5% vs. 97.7%, p = 0.03) than radiologists, respectively. CONCLUSION: The proposed pipeline showed promising performance, especially for extracting cancer risk factors from patient's clinical notes. CLINICAL RELEVANCE STATEMENT: The natural language processing pipeline showed a higher sensitivity for extracting prostate cancer risk factors than radiologists and may help efficiently gather relevant text information when interpreting prostate MRI. KEY POINTS: When interpreting prostate MRI, it is necessary to extract prostate cancer-related information from clinical notes. This pipeline extracted the presence of prostate cancer risk factors with higher sensitivity than radiologists. Natural language processing may help radiologists efficiently gather relevant prostate cancer-related text information.

Increasing Adoption of Left Atrial Appendage Occlusion in Isolated Coronary Artery Bypass Grafting.

BACKGROUND: Recent randomized trial data showed fewer strokes with left atrial appendage occlusion (LAAO) following cardiac surgery in patients with atrial fibrillation. We developed a quality initiative to increase LAAO adoption. METHODS: Among 11,099 patients undergoing isolated CABG between January 2019-March 2021 at 33 hospitals in Michigan, those with atrial fibrillation undergoing first-time, on-pump CABG were eligible (n=1,241). A goal LAAO rate of 75% was selected as a quality improvement target through a statewide collaborative. An interrupted time series analysis evaluated the change in LAAO rate before (January-December 2019) versus after (January 2020-March 2021) implementation. RESULTS: Implementation of the quality metric improved LAAO rate from 61% (357/581) before to 79% (520/660) after implementation (p<0.001). Compared to patients not undergoing concomitant LAAO, LAAO patients (71%, 877/1,241) were older, more frequently male, and had a lower STS-PROM (2.9±3.5% vs. 3.7±5.7%, p=0.003), while other baseline characteristics including CHA2DS2-VASc scores were similar. Mean bypass and cross-clamp times were 7 and 6 minutes longer, respectively, in the LAAO group among those who did not undergo concomitant ablation. Operative mortality, major morbidity, blood product administration, and thromboembolic events were similar between groups. Interrupted time series analysis showed a significant increase in LAAO rate after implementation (p=0.009). CONCLUSIONS: LAAO in patients with atrial fibrillation undergoing isolated CABG did not add operative risk versus isolated CABG without LAAO. A statewide quality improvement initiative was successful in increasing the rate of concomitant LAAO and could be further evaluated as a potential quality metric in cardiac surgery.

Sex differences in brain resilience of individuals with multiple sclerosis.

BACKGROUND: Brain resilience allows maintenance of neurocognitive function in the face of age or disease-related neural changes. OBJECTIVE: Test the hypothesis that women and men with MS differ in brain resilience. METHODS: This cross-sectional analysis of prospective cohort data included 11,297 patients. Linear mixed effects models predicted performance outcomes on tasks of fine motor dexterity and cognitive processing speed for MRI proxies of disease burden: brain parenchymal fraction (BPF), T2 lesion volume, volumes of deep gray, thalamus, white and cortical gray matter. Covariates were age, sex, age-by-sex, current disease-modifying therapy, disease phenotype, education, total brain volume, and total brain volume-by-sex. Sex-by-MRI metric terms tested primary hypothesis of differential brain-behavior relationships between men and women. RESULTS: Final sample included 10,286 participants. Lower BPF was associated with worse performance (p's<0.001) in men and women; association was smaller for women than men for processing speed (ßetaWomen-Men=-0.044, 95 % CI=[-0.087, -0.002], p = 0.041) and manual dexterity (ßetaWomen-Men=-0.073, 95 % CI=[-0.124, -0.023], p = 0.005). For each MRI variable, women demonstrated better neurocognitive function controlling for disease burden. DISCUSSION: Sex differences in brain metric-neurofunctional performance relationships of people with MS suggest women have higher resilience than men in the face of increased disease burden. Future work exploring mechanism is warranted.

Perioperative Evaluation and Management of Children with Osteoporosis and Low Bone Mineral Density.

As medical and surgical treatment options for children with osteoporosis expand, multidisciplinary strategies for bone health optimization become more important. Each patient's bone mineral density and fracture history should be interpreted in context. Off-label bisphosphonate use is a standard pharmacologic intervention for children with osteoporosis for optimal bone accrual. It is possible to continue this therapy perioperatively under certain circumstances. The rare side effects (osteonecrosis of the jaw and atypical femur fractures) seem less common in children. Physical therapy, vitamin D supplementation, and other interventions are also important tools for optimal bone health perioperatively and for satisfactory surgical outcomes.

A narrative review of telemedicine and its adoption across specialties.

Background and Objective: Telemedicine and video consultation are crucial advancements in healthcare, allowing remote delivery of care. Telemedicine, encompassing various technologies like wearable devices, mobile health, and telemedicine, plays a significant role in managing illnesses and promoting wellness. The corona virus disease 2019 (COVID-19) pandemic accelerated the adoption of telemedicine, ensuring convenient access to medical services while maintaining physical distance. Legislation has supported its integration into clinical practice and addressed compensation issues. However, ensuring clinical appropriateness and sustainability of telemedicine post-expansion has gained attention. We south to identify the most friendly and resistant specialties to telemedicine and to understand areas of interest within those specialties to grasp potential barriers to its use. Methods: We aimed to identify articles that incorporated telemedicine in any medical or surgical specialty and determine the adoption rate and intent of this new form of care. Additionally, a secondary search within these databases was conducted to analyze the advantages, disadvantages, and implementation of telemedicine in the healthcare system. Non-English articles and those without full text were excluded. The study selection and data collection process involved using search terms such as "medicine", "surgery", "specialties", "telemedicine", and "telemedicine". Key Content and Findings: Telemedicine adoption varies among specialties. The pandemic led to increased usage, with telemedicine consultations comprising 30.1% of all visits, but specialties like mental health, gastroenterology, and endocrinology showed higher rates of adoption compared to optometry, physical therapy, and orthopedic surgery. Conclusions: The data shows that telemedicine uptake varies by specialty and condition due to the need for physical exams. In-person visits still dominate new patient visits despite increased telemedicine use. Telemedicine cannot fully replace in-person care but has increased visit volume and is secure. The adoption of telemedicine is higher in medical practices than in surgical practices, with neurosurgery and urology leading. Further research is needed to assess telemedicine's suitability and effectiveness in different specialties and conditions.

A conserved chronobiological complex times C. elegans development.

The mammalian PAS-domain protein PERIOD (PER) and its C. elegans orthologue LIN-42 have been proposed to constitute an evolutionary link between two distinct, circadian and developmental, timing systems. However, while the function of PER in animal circadian rhythms is well understood molecularly and mechanistically, this is not true for the function of LIN-42 in timing rhythmic development. Here, using targeted deletions, we find that the LIN-42 PAS domains are dispensable for the protein's function in timing molts. Instead, we observe arrhythmic molts upon deletion of a distinct sequence element, conserved with PER. We show that this element mediates stable binding to KIN-20, the C. elegans CK1δ/ε orthologue. We demonstrate that CK1δ phosphorylates LIN-42 and define two conserved helical motifs, CK1δ-binding domain A (CK1BD-A) and CK1BD-B, that have distinct roles in controlling CK1δ-binding and kinase activity in vitro. KIN-20 and the LIN-42 CK1BD are required for proper molting timing in vivo. These interactions mirror the central role of a stable circadian PER-CK1 complex in setting a robust ~24-hour period. Hence, our results establish LIN-42/PER - KIN-20/CK1δ/ε as a functionally conserved signaling module of two distinct chronobiological systems.

MLT-11 is a transient apical extracellular matrix component required for cuticle patterning and function.

Apical extracellular matrices (aECMs) are associated with all epithelia and form a protective layer against biotic and abiotic threats in the environment. Despite their importance, we lack a deep understanding of their structure and dynamics in development and disease. C. elegans molting offers a powerful entry point to understanding developmentally programmed aECM remodeling. A transient matrix is formed in embryos and at the end of each larval stage, presumably to pattern the new cuticle. Focusing on targets of NHR-23, a key transcription factor which drives molting, we identified the Kunitz family protease inhibitor gene mlt-11 as an NHR-23 target. We identified NHR-23-binding sites that are necessary and sufficient for epithelial expression. mlt-11 is necessary to pattern every layer of the adult cuticle, suggesting a broad patterning role prior to the formation of the mature cuticle. MLT-11::mNeonGreen::3xFLAG transiently localized to the aECM in the cuticle and embryo. It was also detected in lining openings to the exterior (vulva, rectum, mouth). Reduction of mlt-11 function disrupted the barrier function of the cuticle. Tissue-specific RNAi suggested mlt-11 activity is primarily necessary in seam cells and we observed alae and seam cell fusion defects upon mlt-11 inactivation. Predicted mlt-11 null mutations caused fully penetrant embryonic lethality and elongation defects suggesting mlt-11 also plays an important role in patterning the embryonic sheath. Finally, we found that mlt-11 inactivation suppressed the blistered cuticle phenotype of mutants of bli-4 mutants, a subtilisin protease gene but did not affect BLI-4::sfGFP expression. These data could suggest that MLT-11 may be necessary to assure proper levels of BLI-4 activity.

Ocular Dirofilariasis: A Clinicopathologic Case Series and Literature Review.

Purpose: Ocular dirofilariasis is an uncommon zoonotic infection that is usually associated with a carnivore host. In this case series and literature review, we investigate the clinical presentation, management, and histopathology of ocular dirofilariasis. Methods: The database at the Florida Lions Ocular Pathology Laboratory was searched for surgical specimens at the Bascom Palmer Eye Institute under approval of the Institutional Review Board. Patients with a histopathologic diagnosis of dirofilariasis between the years 1962 and 2022 from the Florida Lions Ocular Pathology Laboratory database were included (n = 3). A systematic PubMed search was conducted by two independent authors to identify published cases of ophthalmic dirofilariasis worldwide. Keywords were used to identify articles, and exclusion criteria were applied. Results: Three patients, two males and one female, were identified from the Florida Lions Ocular Pathology Laboratory database with a diagnosis of ocular dirofilariasis. The mean age was 46.7 years (with a range 33-57 years). There were two eyelid lesions (Cases 1 and 3) and one involving the subconjunctival space (Case 2). All three organisms were excised and presumptively identified as Dirofilaria tenuis. All 3 patients were managed with curative surgical removal and recovered completely. Our review of the literature identified 540 published reports and 142 published reports with 186 cases that met the exclusion criteria. Conclusion: We present a case series and literature review of ocular dirofilariasis. Knowledge of the incidence, risk factors, prevention, and diagnosis of this unique parasitic infection will help in proper management and prevent further ocular complications.

Quantifying Diaphragm Blood Flow With Contrast-Enhanced Ultrasound in Humans.

BACKGROUND: Despite the known interplay between blood flow and function, there is currently no minimally invasive method to monitor diaphragm hemodynamics. We used contrast-enhanced ultrasound (CEUS) to quantify relative diaphragm blood flow (Q˙DIA) in humans and assessed the technique's efficacy and reliability during graded inspiratory pressure threshold loading. We hypothesized that: (1) Q˙DIA would linearly increase with pressure generation: and (2) that there would be good test-retest reliability and interanalyzer reproducibility. RESEARCH QUESTION: Can the first minimally invasive method to measure relative diaphragm blood flow be validated in humans? STUDY DESIGN AND METHODS: Quantitative contrast-enhanced ultrasound of the costal diaphragm was performed in healthy participants (10 male subjects, 6 female subjects; mean age 28 ± 5 years; BMI 22.8 ± 2.0 kg/m) during unloaded breathing and three stages of loaded breathing on two separate days. Gastric and esophageal balloon catheters measured diaphragmatic pressure. Ultrasonography was performed during a constant-rate IV infusion of lipid-stabilized microbubbles following each stage. Ultrasound images were acquired after a destruction-replenishment sequence and diaphragm specific time-intensity data were used to determine Q˙DIA by two individuals. RESULTS: Transdiaphragmatic pressure for unloaded and each loading stage were 15.2 ± 0.8, 26.1 ± 0.8, 34.6 ± 0.8, and 40.0 ± 0.8 percentage of the maximum, respectively. Q˙DIA increased with each stage of loading (3.1 ± 3.1, 6.9 ± 3.6, 11.0 ± 4.9, and 13.5 ± 5.4 AU/s; P < .0001). The linear relationship between diaphragmatic flow and pressure was reproducible from day to day. Q˙DIA had good to excellent test-retest reliability (0.86 [0.77, 0.92]; P < .0001) and excellent interanalyzer reproducibility (0.93 [0.90, 0.95]; P < .0001) with minimal bias. INTERPRETATION: Relative Q˙DIA measurements have valid physiological underpinnings, are reliable day to day, and reproducible analyzer-to-analyzer. Contrast-enhanced ultrasound is a viable, minimally invasive method for assessing costal Q˙DIA in humans and may provide a tool to monitor diaphragm hemodynamics in clinical settings.

Using modified Fenn diagrams to assess ventilatory acclimatization during ascent to high altitude: Effect of acetazolamide.

High altitude (HA) ascent imposes systemic hypoxia and associated risk of acute mountain sickness. Acute hypoxia elicits a hypoxic ventilatory response (HVR), which is augmented with chronic HA exposure (i.e., ventilatory acclimatization; VA). However, laboratory-based HVR tests lack portability and feasibility in field studies. As an alternative, we aimed to characterize area under the curve (AUC) calculations on Fenn diagrams, modified by plotting portable measurements of end-tidal carbon dioxide ( P ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) against peripheral oxygen saturation ( S p O 2 ${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) to characterize and quantify VA during incremental ascent to HA (n = 46). Secondarily, these participants were compared with a separate group following the identical ascent profile whilst self-administering a prophylactic oral dose of acetazolamide (Az; 125 mg BID; n = 20) during ascent. First, morning P ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ and S p O 2 ${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}}}$ measurements were collected on 46 acetazolamide-free (NAz) lowland participants during an incremental ascent over 10 days to 5160 m in the Nepal Himalaya. AUC was calculated from individually constructed Fenn diagrams, with a trichotomized split on ranked values characterizing the smallest, medium, and largest magnitudes of AUC, representing high (n = 15), moderate (n = 16), and low (n = 15) degrees of acclimatization. After characterizing the range of response magnitudes, we further demonstrated that AUC magnitudes were significantly smaller in the Az group compared to the NAz group (P = 0.0021), suggesting improved VA. These results suggest that calculating AUC on modified Fenn diagrams has utility in assessing VA in large groups of trekkers during incremental ascent to HA, due to the associated portability and congruency with known physiology, although this novel analytical method requires further validation in controlled experiments. HIGHLIGHTS: What is the central question of this study? What are the characteristics of a novel methodological approach to assess ventilatory acclimatization (VA) with incremental ascent to high altitude (HA)? What is the main finding and its importance? Area under the curve (AUC) magnitudes calculated from modified Fenn diagrams were significantly smaller in trekkers taking an oral prophylactic dose of acetazolamide compared to an acetazolamide-free group, suggesting improved VA. During incremental HA ascent, quantifying AUC using modified Fenn diagrams is feasible to assess VA in large groups of trekkers with ascent, although this novel analytical method requires further validation in controlled experiments.

Triggered Release of Ampicillin from Metallic Implant Coatings for Combating Periprosthetic Infections.

Periprosthetic infections caused by Staphylococcus aureus (S. aureus) pose unique challenges in orthopedic surgeries, in part due to the bacterium's capacity to invade surrounding bone tissues besides forming recalcitrant biofilms on implant surfaces. We previously developed prophylactic implant coatings for the on-demand release of vancomycin, triggered by the cleavage of an oligonucleotide (Oligo) linker by micrococcal nuclease (MN) secreted by the Gram-positive bacterium, to eradicate S. aureus surrounding the implant in vitro and in vivo. Building upon this coating platform, here we explore the feasibility of extending the on-demand release to ampicillin, a broad-spectrum aminopenicillin ß-lactam antibiotic that is more effective than vancomycin in killing Gram-negative bacteria that may accompany S. aureus infections. The amino group of ampicillin was successfully conjugated to the carboxyl end of an MN-sensitive Oligo covalently integrated in a polymethacrylate hydrogel coating applied to titanium alloy pins. The resultant Oligo-Ampicillin hydrogel coating released the ß-lactam in the presence of S. aureus and successfully cleared nearby S. aureus in vitro. When the Oligo-Ampicillin-coated pin was delivered to a rat femoral canal inoculated with 1000 cfu S. aureus, it prevented periprosthetic infection with timely on-demand drug release. The clearance of the bacteria from the pin surface as well as surrounding tissue persisted over 3 months, with no local or systemic toxicity observed with the coating. The negatively charged Oligo fragment attached to ampicillin upon cleavage from the coating did diminish the antibiotic's potency against S. aureus and Escherichia coli (E. coli) to varying degrees, likely due to electrostatic repulsion by the anionic surfaces of the bacteria. Although the on-demand release of the ß-lactam led to adequate killing of S. aureus but not E. coli in the presence of a mixture of the bacteria, strong inhibition of the colonization of the remaining E. coli on hydrogel coating was observed. These findings will inspire considerations of alternative broad-spectrum antibiotics, optimized drug conjugation, and Oligo linker engineering for more effective protection against polymicrobial periprosthetic infections.