Journal of Dental Research

Aim: Cross-sectional summaries of periodontitis based on clinical attachment loss (CAL) are, by definition, conditioned on surviving teeth. Because the most severely affected teeth are more likely to have been lost, these measures may underestimate cumulative disease burden and show an artificial flattening (attenuation) of severity with age. We hypothesised that measures more sensitive to severe attachment loss would show greater attenuation at older ages than measures defined across a broader range of sites. Materials and Methods: Using nationally representative data from adults aged 30+ years in NHANES 2009-2014, we examined age-specific trajectories across multiple continuous measures of periodontal severity and assessed whether divergence between measures followed the pattern predicted under severity-dependent tooth loss. Results: The proportion of observable sites declined from 93% at ages 30-34 to 68% at 80+ years, establishing the structural basis for the divergence observed across severity measures. All severity measures showed nonlinear attenuation with age, with distortion increasing with severity threshold. Higher-threshold measures exhibited the greatest attenuation, while lower-threshold measures showed more stable trajectories. Conclusions: Cross-sectional summaries of periodontitis reflect disease among surviving teeth rather than cumulative damage across teeth originally at risk. Attenuation at older ages is consistent with depletion of the most severely affected teeth rather than biological slowing. Distortion varies by measure, with higher-threshold and mean-based indices most affected, whereas the CAL 3+ mm threshold provides a more stable basis for age comparisons.

BackgroundFriction at the bracket-archwire interface is traditionally considered a key determinant of orthodontic tooth movement efficiency. However, clinical evidence remains inconsistent despite advances in low-friction systems, including self-ligating brackets, coated archwires, and frictionless mechanics. ObjectiveTo evaluate the clinical impact of friction-related interventions on tooth movement, anchorage control, and patient-centered outcomes. MethodsA scoping review with supplementary meta-analysis was conducted following PRISMA-ScR guidelines. Electronic searches of the Cochrane Library (1 systematic review: CD003453), PubMed (128 primary studies), and Google Scholar (approximately 2,500 results, screened to 45 relevant studies) were performed in February 2026 . Randomized controlled trials comparing friction-modifying interventions were included. Primary outcomes included rate of tooth movement, anchorage loss, and molar rotation. Secondary outcomes included pain and treatment duration. Random-effects meta-analysis (DerSimonian-Laird method) was performed using RevMan 5.4; this method was chosen due to expected clinical heterogeneity . Heterogeneity was assessed using the I{superscript 2} statistic and classified using non-overlapping thresholds: 0-40% low, 40-60% moderate, 60-90% substantial, and 90-100% considerable heterogeneity. Risk of bias was assessed using Cochrane RoB 2, and certainty of evidence was evaluated using GRADE. Given the small number of studies, pooled estimates should be interpreted cautiously due to potential small-study effects. ResultsNineteen RCTs were included in quantitative synthesis. Frictionless mechanics did not significantly increase the rate of space closure (MD = 0.15 mm/month; 95% CI: -0.08 to 0.38; P = 0.20; I{superscript 2} = 68% [substantial heterogeneity]) but resulted in significantly greater molar rotation (MD = 6.1 degrees; 95% CI: 4.8 to 7.4; P < 0.001; I{superscript 2} = 45% [moderate heterogeneity]) . Self-ligating brackets showed no consistent advantage in treatment duration or pain reduction. Active self-ligating brackets demonstrated slightly faster alignment than passive systems (MD = 10.24 days; 95% CI: 2.80 to 17.68). Low-friction ligatures and coated archwires did not improve clinical efficiency. Surgical acceleration methods reduced treatment time by 25-50% but increased early discomfort. Low-level laser therapy showed potential for accelerating tooth movement and reducing pain. ConclusionsHigh-level clinical evidence does not support the long-held assumption that reducing friction accelerates orthodontic tooth movement. The evidence fails to demonstrate a clinically meaningful acceleration effect from friction reduction alone. Resistance to sliding appears to be predominantly governed by binding and biological patient response, not friction alone--necessitating a shift in biomechanical strategy. A proposed evidence-informed conceptual model and clinical algorithm are presented to guide decision-making.

Background: Periodontitis is defined by cumulative, irreversible tissue destruction, yet population-based measurement typically relies on cross-sectional indicators derived from retained teeth. Destruction that occurred earlier in life, particularly disease severe enough to result in tooth loss, is structurally excluded from these measures, potentially leading to systematic underestimation of lifetime periodontal burden. Objective: To develop and evaluate a measurement framework that estimates lifetime periodontal burden from cross-sectional data by explicitly incorporating informative tooth loss under etiological uncertainty. Methods: Data were drawn from 10,324 adults aged [&ge;]30 years participating in the 20090-2016 National Health and Nutrition Examination Survey (NHANES) who completed full-mouth periodontal examination and glycated hemoglobin (HbA1c) testing. Lifetime periodontal burden was estimated by combining observed clinical attachment loss in retained teeth with probabilistic contributions from missing teeth, using three alternative age-stratified attribution schedules derived from epidemiological studies of periodontal extraction. Performance was compared with conventional measures of periodontal severity and extent using distributional analyses, correlations with HbA1c, discrimination of diabetes status, and relative importance analysis. Age-adjusted models were treated as sensitivity analyses. Results: Estimated lifetime periodontal burden exhibited strong, monotonic age gradients across glycemic categories, in contrast to more attenuated patterns observed for severity and extent. Across attribution schedules, lifetime burden showed stronger correlations with HbA1c ({rho} = 0.30-0.32) than conventional measures. In multivariable models including all indices, lifetime burden retained an independent association with HbA1c, whereas severity and extent contributed little unique information. Discriminative performance for diabetes status was consistently higher for lifetime burden than for conventional measures and remained stable across attribution schedules. Conclusions: Lifetime periodontal burden can be estimated from cross-sectional data by explicitly modelling informative tooth loss rather than restricting measurement to retained teeth. Incorporating historical tissue loss under uncertainty yields a more coherent representation of cumulative periodontal destruction than snapshot-based measures and provides a methodological basis for life-course-oriented periodontal epidemiology.

IntroductionDiscrimination within oral health care settings is increasingly recognized as a contributor to oral health inequities, shaping patient trust, care-seeking behaviors, and health outcomes. While prior research has documented discriminatory experiences among racially and ethnically minoritized populations, nationally representative evidence on discrimination and dignity in dental care among LGBTQ+ adults remains limited. This study examines differences in discrimination and microaggressions in dental settings by LGBTQ+ status, sexual orientation, and gender identity. MethodsThis study analyzed pooled data from the 2022-2025 waves of the State of Oral Health Equity in America (SOHEA) survey, a nationally representative survey of U.S. adults aged 18 and older. Discrimination was measured using the Everyday Discrimination Scale-Oral Care (EDSOC), and microaggressions were assessed using the Dignity in Oral Care Scale (DOCS). Descriptive and bivariate analyses compared mean scores across identity groups. Multivariable linear regression models estimated associations between LGBTQ+ status, sexual orientation, and gender identity with EDSOC and DOCS scores, adjusting for sociodemographic characteristics and dental insurance status. Analyses focused on group differences and associations and were conducted without applying survey weights. ResultsThe analytic sample included 15,591 adults from the 2022-2025 SOHEA surveys with complete data (52.5% of the total N=29,679); 12% identified as LGBTQ+. Overall, LGBTQ+ individuals in the analytic sample reported significantly higher mean discrimination (EDSOC: 2.97, SD=4.99) and microaggression (DOCS: 2.19, SD=3.22) scores than non-LGBTQ+ individuals (EDSOC: 1.72, SD=3.79; DOCS: 1.62, SD=2.80; p<0.001). Questioning individuals and those with gender identities categorized as "other" had the highest mean EDSOC and DOCS scores (p<0.001). In adjusted models controlling for sociodemographic and insurance factors, LGBTQ+ identity remained significantly associated with higher EDSOC ({beta}=0.16, 95% CI=0.11-0.21) and DOCS ({beta}=0.08, 95% CI=0.03-0.13) scores. Sexual orientation and gender identity differences persisted, with questioning and gender-diverse individuals experiencing significantly higher levels of discrimination and microaggressions in dental settings. DiscussionFindings demonstrate that LGBTQ+ adults, particularly adults identifying as questioning and those with nonbinary or other gender identities, experience disproportionate discrimination and microaggressions in dental care settings. Addressing interpersonal and structural sources of bias in oral health care is critical to advancing equity and improving access to respectful, high-quality care for LGBTQ+ populations.

BackgroundTrauma from occlusion (TFO) is a frequently under-recognized clinical entity. While narrative reviews exist, no prior systematic review has quantitatively synthesized the prevalence of TFO signs in orthodontic patients, the distribution of the Akerly classification for deep traumatic overbite, the efficacy of orthodontic intrusion, or the outcomes of immediate orthodontic repositioning of traumatized incisors. Furthermore, the knowledge-practice gap among orthodontists regarding trauma management has not been meta-analyzed. MethodsSystematic review and meta-analysis of observational and interventional studies, including cross-sectional studies, randomized controlled trials, and before-after studies. We searched PubMed (n=57), PubMed Central (n=538), the Cochrane Library (n=11: 2 reviews, 9 trials), and Google Scholar (~3,930) up to December 2025. Studies reporting prevalence of TFO signs, Akerly classification distribution, overbite reduction following orthodontic intrusion, success of immediate orthodontic repositioning, or orthodontist knowledge/practice were included. Random-effects meta-analyses were performed using the meta package in R (DerSimonian-Laird estimation for {tau}2). The protocol was not registered due to the exploratory nature of this multi-domain synthesis; however, the methodology strictly adhered to PRISMA 2020 guidelines. ResultsTwenty-seven studies (n=8,432 participants) were included. The pooled prevalence of any TFO sign was 34% (95%CI:27-42%, I2=86%), with wide prediction intervals indicating substantial between-study variability. TFO was variably defined across studies as the presence of [&ge;]1 of the following: fremitus, increased mobility, occlusal interference, soft tissue trauma, or CR-CO discrepancy. Higher prevalence was observed in Class II malocclusion (46% vs. 22%). Among deep traumatic overbite cases classified using the Akerly system, Type II was most common (52%, 95%CI:44-60%), followed by Type I (31%) and Type III (17%). Orthodontic intrusion reduced overbite by a mean of 2.8 mm (95%CI:2.1-3.5, I2=72%); TAD-assisted intrusion produced greater reduction (3.4 mm) than conventional archwires (2.1 mm, p<0.001). Immediate orthodontic repositioning of traumatized incisors with light forces ([&le;]50 g) achieved 91% success (95%CI:84-96%) at 12 months, comparable to splinting (84%), with no statistically significant difference between groups. The orthodontic group required fewer visits and reported better comfort. Meta-analysis of orthodontist knowledge showed correct awareness of specific trauma management protocols was below 40% in most domains, indicating a substantial evidence-practice gap. ConclusionThis first systematic review and meta-analysis on TFO in orthodontics provides preliminary quantitative benchmarks. One-third of orthodontic patients exhibit TFO signs; Akerly Type II is the dominant deep overbite pattern; orthodontic intrusion effectively reduces overbite by approximately 3 mm; immediate light-force repositioning is comparable to splinting in success and superior in efficiency. However, the disconnect between high clinical efficacy (e.g., 91% success of repositioning) and low practitioner awareness (<40%) represents a substantial translational gap in clinical practice. Assessment of publication bias was limited due to the small number of studies in several analyses (<10), precluding reliable funnel plot interpretation.

BackgroundCommercial dental artificial intelligence in 2026 is over-whelmingly diagnostic: caries, calculus, periapical, and bone-level detection on radiographs. The clinically harder question that follows every diagno-sis -- given a patients chart and most recent procedure, what should the dentist do next -- remains unsolved at general-dentistry scale. The closest published system, MultiTP (Chen et al., 2024), is a CNN-RNN restricted to partial-edentulism cases and provides neither calibrated uncertainty, structured rationale, nor an evaluation that treats the model as decision support rather than as an autonomous classifier. MethodsWe introduce DentaCoPilot, a recommender that, given a structured chart, returns (i) a calibrated top-K probability distribution over Current Dental Terminology (CDT) codes for the next procedure, (ii) a verbalised confidence label, (iii) an explicit abstain flag when context is insufficient, and (iv) a chartgrounded rationale. We compare four classical baselines (frequency bigram, TF-IDF + logistic regression, XGBoost, MultiTP-style CNN-RNN) and six large-language-model (LLM) variants (Claude Haiku, Sonnet + chain-of-thought, Sonnet + retrieval, Opus + chain-of-thought, Sonnet + classical prior, Opus + classical prior) on a synthetic chart corpus of 500 patients (1,284 test examples). All LLM inference is routed through the local Anthropic Claude Code CLI; every call is logged for full audit. ResultsOn apples-to-apples evaluation, classical baselines reach 0.567 top-1 / 0.967 top-5; pure LLM variants trail at 0.267-0.467 top-1. Prompt-conditioning a Sonnet LLM on the classical baselines top-10 candidates (M5) closes the gap: top-5 rises from 0.733 (pure Sonnet + chain-of-thought) to 0.933, matching classical baselines, while preserving rationale and abstention. Increasing the LLM backbone from Sonnet to Opus does not improve accuracy with or without priming. Calibration via temperature scaling and coverage-risk analysis is reported for the baselines. ConclusionPrompt-conditioning a small LLM on a classical baselines top-K is the most cost-effective LLM design we tested for next-procedure recommendation, and the design preserves the augmentation features that distinguish the system from an autonomous classifier. A pre-registered clinician-in-the-loop evaluation at the KLE Vish-wanath Katti Institute of Dental Sciences (Belgaum, India) and a real-data evaluation on the multi-institutional BigMouth dental data repository are the next stage of work.

Objective: To identify Dickkopf-1 (DKK1) as a prognostically relevant candidate in head and neck squamous cell carcinoma and to evaluate whether DKK1 and cytoskeleton-associated protein 4 (CKAP4) expression is associated with cervical lymph node metastasis in tongue squamous cell carcinoma (TSCC). Methods: DKK1 was screened using the Human Protein Atlas Pathology Atlas. Immunohistochemical expression of DKK1 and CKAP4 was examined in 54 patients with primary TSCC (cT1-4N0) treated surgically between 2015 and 2020. Nine cases were excluded because of insufficient tissue blocks or inadequate staining quality, leaving 45 evaluable cases. Associations with delayed cervical lymph node metastasis were assessed together with conventional clinicopathological factors, including infiltrative growth pattern (INF) and pathological depth of invasion (pDOI). Results: In public database analysis, high DKK1 expression was associated with poorer overall survival in head and neck squamous cell carcinoma. In the TSCC cohort, pDOI [&ge;]5 mm and INF pattern c were significantly associated with cervical lymph node metastasis. Positive DKK1 and CKAP4 expression were also significantly associated with cervical lymph node metastasis. Furthermore, combined DKK1/CKAP4 positivity, when incorporated with INF and pDOI, provided additional risk stratification, and cases with all 3 factors showed a markedly increased likelihood of cervical lymph node metastasis. Conclusions: Expression of DKK1 and CKAP4 was associated with cervical lymph node metastasis in TSCC. Combined assessment of DKK1/CKAP4 expression with INF and pDOI may improve pathological risk stratification and may help identify patients who require closer neck evaluation and postoperative management.

Background The COVID-19 pandemic has caused significant global mortality. Despite declining infection rates, new variants of SARS-CoV-2 continue to emerge, necessitating new prevention strategies. Objective This study aimed to evaluate the effect of four over-the-counter (OTC) antiseptic mouthwash/gargling solutions in the U.S., compared with a distilled water control, on SARS-CoV-2 viral load across multiple oral and oropharyngeal sample types. Methods This pilot single-center randomized controlled clinical trial enrolled adults in the San Francisco Bay Area, California, who tested positive for COVID-19. Participants were randomized to distilled water, chlorine dioxide, hydrogen peroxide, cetylpyridinium chloride, and essential oils. Participants were instructed to rinse and gargle four times daily for four weeks using standardized instructions to ensure protocol adherence. Samples were collected on Days 1, 7, and 28 and analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The primary outcome was the change in SARS-CoV-2 viral load from baseline to Day 28, assessed using cycle threshold (Ct) values. Secondary outcomes included self-reported clinical symptoms and hospitalization. Results Forty-nine participants completed the study. No mouthwash demonstrated a statistically significant reduction in SARS-CoV-2 viral load over time. Cetylpyridinium chloride showed a transient increase in Ct values on Day 7 that was not sustained on Day 28. At baseline, throat swab samples had the lowest Ct values across all sample types. Due to limited subgroup sample sizes for secondary outcome measures, no statistical or moderator analyses were conducted. Conclusion Further large-scale randomized trials are needed before recommending antiseptic mouthwashes for SARS-CoV-2 prevention or management.

Severe salivary gland injury can cause chronic xerostomia and persistent secretory dysfunction, yet the epithelial populations that support repair remain poorly defined. Here, we identify NGFR/Ngfr as a conserved surface marker for isolating organoid-forming epithelial stem/progenitor cells from human and mouse salivary glands and show that mouse Ngfr-lineage cells contribute to ductal-acinar regeneration after injury. Single-cell transcriptomic analysis of human salivary gland tissue identified a restricted NGFR-expressing basal duct epithelial subpopulation with progenitor-like features and early positions along inferred epithelial differentiation trajectories. Functionally, NGFR-expressing cells showed enhanced primary and secondary organoid-forming capacity, and NGFR-enriched human organoids engrafted after transplantation into injured salivary glands of immunodeficient mice. In mouse salivary glands, isolated Ngfr-expressing cells showed enriched organoid-forming activity, and Ngfr expression localized to injury-associated ductal regions after duct ligation and local inflammatory injury. Ngfr-CreERT2 lineage tracing further showed that Ngfr-lineage cells contribute to ductal and acinar compartments during post-injury regeneration. Together, these findings establish NGFR/Ngfr as a conserved surface marker for prospectively isolating basal duct epithelial stem/progenitor populations with organoid-forming activity and injury-responsive ductal-acinar regenerative potential.

This work aimed to establish a translationally viable, xeno-free, serum-free platform and protocol for the isolation and expansion of human salivary stem/progenitor cells (hS/PCs) suitable for regulatory qualification and future FDA-approved first-in-human autologous regenerative therapy trials for the treatment of hyposalivation disorders. Parotid gland specimens from non-cancerous regions/tissues were collected from consented surgical patients. Primary hS/PCs were isolated from tissue specimens, cultured in animal-component-free conditions, expanded to produce millions of cells, then enriched for CD44+ stem/progenitor cells by magnetic cell sorting. Normal epithelial purity was assessed using cytokeratins 5/14. Anti-CD133/PROM1 (cancer marker) and anti- fibroblast (clone TE-7) antibodies were used to demonstrate a lack of contaminating cells. Phenotype validation was performed by flow cytometry and immunocytochemistry on both CD44+ sorted and unsorted populations. Senescence-associated beta-galactosidase (SA-{beta}-gal) assays were performed across serial passages (P1-P6). Pluripotency was demonstrated by culture under conditions supporting lineage-specific differentiation. Primary hS/PCs demonstrated consistent expansion and epithelial morphology under serum-free conditions. CD44 expression remained high (>95%) throughout expansion, with negligible detection of CD133 or fibroblast markers, confirming epithelial purity and absence of tumorigenic or stromal contamination. Immunocytochemistry corroborated these expression profiles. SA-{beta}-gal staining revealed only a minor, passage-dependent increase (5-16%) in senescent cells from multiple donors, indicating retention of proliferative potential. Our defined, animal-free culture system supports stable expansion of pure low passage hS/PCs under conditions compatible with good manufacturing practice (GMP).

Organismal tolerance of ionizing radiation is a complex trait whose genetic basis has been studied extensively, in large part due to its significance to human health and technological advancement. Conventional mutant screens in model organisms have revealed the paramount role of DNA damage response (DDR) and repair pathways in determining tolerance to ionizing radiation. However, uncovering natural genetic variation in radiotolerance is also of critical importance, as individual differences are associated with the differential susceptibility to cancer as well as differential response to radiation treatment. Genetic variation that underlies phenotype differences in natural populations often occurs in distinct genes and pathways as compared to the genes of major effect revealed by mutant screens, owing to the impact of natural selection on the former. We therefore sought to isolate natural variation in radiotolerance of Drosophila melanogaster by performing extreme QTL mapping. We generated a large genetically diverse multiparental population and exposed 3rd instar larvae to a semi-lethal dose or ionizing radiation. By sequencing surviving adults and comparing their haplotypes to unexposed controls from the same population, we identified a single major effect QTL spanning the 3rd chromosome centromere. The QTL contains 34 genes, none of which are previously implicated in radiotolerance. We interrogated the impact of these genes on radiotolerance through forward genetic analysis and RNA-seq. Our findings implicate diverse processes in radiotolerance including cell-cycle regulation and innate immune function.

Bdelloid rotifers are known to survive desiccation and high doses of ionizing radiation. This extreme resistance is notably due to their capacity to cope with numerous DNA double-strand breaks (DSBs). Genes encoding key components of the non-homologous end joining (NHEJ) DNA repair pathway are strongly upregulated in the bdelloid rotifer Adineta vaga following exposure to ionizing radiation. Considering the notably high doses tolerated by these organisms, their capacity to efficiently restore genome integrity is particularly striking. Although NHEJ is generally regarded as less accurate than homologous recombination (HR), the absence of major genomic rearrangements in the descendants of irradiated rotifers suggests that DNA repair occurs with high fidelity. Terwagne et al. recently reported a delayed repair in germline nuclei, occurring during oocyte development when homologous chromosomes pair, thereby enabling template-based repair through HR. In this study, we established an in situ hybridization approach on A. vaga cryosections to investigate the spatial and temporal expression of key actors involved in NHEJ, HR, and Base excision repair (BER) pathways in somatic and germline tissues. We show that NHEJ (KU80) and BER-related genes (PARPs) as well as A. vaga Ligase E (putatively involved in DNA repair) are expressed early after radiation exposure in the somatic syncytium. In contrast, HR-related genes (Rad51: two paralogs, Rad54), as well as PCNA (involved in DNA replication, NER, BER, HR) are expressed later in maturing oocytes, indicating the activation of a delayed homologous recombination repair pathway in germline nuclei. Nurse cells, which express genes associated with both HR and NHEJ pathways, may rely on both mechanisms for their own DNA repair while also supplying mRNAs to the maturing oocyte. Our results provide new evidence for a differential regulation of DNA DSB repair pathways between soma and germline in bdelloids, with NHEJ predominating in somatic tissues and HR in the germline of A. vaga. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/722046v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@3b1f3borg.highwire.dtl.DTLVardef@17f5eb5org.highwire.dtl.DTLVardef@122ef14org.highwire.dtl.DTLVardef@7e4413_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOAbstract Figure:C_FLOATNO Summary of in situ hybridization results: genes coding for actors of NHEJ are expressed in the somatic nuclei and in the nurse nuclei of Adineta vaga individuals 2.5 hours post X-rays radiation, while genes coding for HR actors and PCNA (involved in multiple pathways including DNA replication and DNA repair: NER, BER, MR, HR) are expressed in the nurse nuclei 2.5 hours post radiation, and later in the maturing oocyte during oogenesis and in the laid eggs. Genes coding for actors highly expressed post-radiation, involved in the BER pathway appear to be only expressed in the somatic syncytium 2.5 hours post radiation, as well as the gene coding for the Ligase E, likely involved in DNA repair. C_FIG

Airborne transmission of respiratory pathogens depends on their ability to remain viable in drying respiratory droplets, yet the physicochemical drivers of bacterial inactivation during droplet evaporation remain poorly quantified. This study combines controlled droplet experiments with physicochemical modeling to investigate how osmotic pressure dynamics influence bacterial survival. Using Escherichia coli and Staphylococcus epidermidis as Gram-negative and Gram-positive surrogates, respectively, we measured viability loss in artificial saliva droplets dried at multiple relative humidities and reconstructed the time-resolved osmotic pressure using the Respiratory Aerosol Model (ResAM). Both organisms remained stable while droplets were liquid but lost viability following efflorescence, when rapid solute concentration changes produced sharp osmotic pressure increases. The extent of inactivation scales log-linearly with the rate of osmotic pressure change around efflorescence: E. coli decays faster than S. epidermidis, and relationships derived in artificial saliva predict survival in independent phosphate-buffered saline experiments. A more rapid drop in humidity led to more severe osmotic shocks and greater inactivation. These results identify the rate of osmotic pressure change during efflorescence as a quantitative, medium-independent predictor of bacterial survival in drying respiratory droplets. ImportanceAirborne infection risk depends on how long microorganisms remain viable in respiratory particles after exhalation, yet the physical mechanisms controlling bacterial survival during droplet drying are not well defined. Evaporation of respiratory droplets concentrates salts and can impose sudden and extreme osmotic stress on microbes, but this process has been difficult to quantify because osmotic pressure cannot be measured directly inside microscopic droplets. Integration of droplet experiments with a physicochemical aerosol model shows that bacterial inactivation is governed primarily by the rate of osmotic pressure increase during droplet efflorescence rather than by static values of humidity or solute concentration alone. This mechanism explains why rapid drying may produce strong inactivation.

PurposeLow-dose radiation-induced adaptive response (LDRIAR) is well documented, but its role in early DNA damage signalling remains unclear. This study aimed to investigate whether adaptive response influences initial DNA double-strand break (DSB) recognition, as reflected by {gamma}H2AX foci formation, and to evaluate its time-dependent expression in human lymphocytes. Materials and MethodsPeripheral blood lymphocytes from three healthy donors were exposed to a priming dose followed by a challenging dose at defined time intervals. DNA damage was assessed using {gamma}H2AX foci analysis, comparing acute and split-dose exposures in both PHA-stimulated (large) and non-stimulated (small) lymphocytes. ResultsA clear time-dependent adaptive response was observed. No significant reduction in {gamma}H2AX foci was detected at 1 h (p > 0.05). At 2 h, a significant decrease was observed ([~]7-8% in large and [~]13% in small lymphocytes; p < 0.01), which increased at 4 h ([~]12% and [~]22%, respectively; p < 0.001). The maximal response occurred at 15 h, with reductions of [~]40- 43% in large and [~]27% in small lymphocytes (p < 0.001). Small lymphocytes exhibited an earlier response, while large lymphocytes showed a greater magnitude at later time points. The temporal trend was consistent across donors, with minor variability at later intervals. ConclusionsThe findings demonstrate that LDRIAR is reflected at the level of DNA damage signalling and follows a defined temporal pattern with cell-type specificity. This suggests that adaptive response may influence early DSB-associated processes, contributing to a better understanding of radiation response mechanisms in radiobiology.

BackgroundSkin is constantly exposed to mechanical forces such as pressure and friction, which need to be sensed and buffered to ensure tissue homeostasis and barrier function. Desmosomes are essential for epidermal integrity, but their role in converting mechanical cues into cellular signaling responses are not well understood. MethodsHere, we combine proteomics and shear-stress assays with live-cell reporters to investigate how desmosomes modulate stress-kinase pathways in keratinocytes. ResultsWe show that the desmosomal adhesion molecule DSG3 is essential not only for cell-cell adhesion but also for modulating p38MAPK and ERK signaling. Loss of DSG3 disrupts mechanotransduction-related protein networks, including the expression of the mechanosensitive channel Piezo1. Under static conditions, DSG3 dampens ERK activity via Piezo1-dependent mechanisms, whereas DSG3 suppresses p38MAPK activity through an independent mechanism. In contrast, DSG3 is required to trigger an activation of both ERK and p38MAPK in response to shear stress in a Piezo1-dependent manner. Experiments with domain-specific DSG3 mutants demonstrate that cell cohesion and signaling responses are partially uncoupled, while maintaining DSG3 tail integrity was crucial for p38MAPK and ERK responses. ConclusionThese findings demonstrate that DSG3 independently coordinates adhesion and mechanotransduction in a domain-specific manner, providing novel insights into how DSG3 contributes to epithelial integrity under dynamic mechanical environments.

Myosin 3A (MYO3A) is an unconventional myosin involved in the formation and maintenance of hair-cell stereocilia of the sensory epithelia in the inner ear. The kinase domain has been implicated in phosphoregulation of MYO3A activity through intermolecular autophosphorylation. Previous studies using mass spectrometry identified two potential phosphorylation sites in the motor domain. To investigate the regulatory roles of these sites, we generated glutamic acid point mutations in our mchr-MYO3A{Delta}K construct to mimic phosphorylation and assayed the constructs for their ability to tip-localize and influence filopodial density via transfection into COS7 cells. The phosphomimic constructs were less able to generate filopodia when compared to wildtype constructs. To gain a better understanding of the phosphoregulation of MYO3A, we transfected COS7 cells with mchr-MYO3A{Delta}K in combination with GFP-tagged full-length MYO3A (GFP-MYO3AFL), or GFP attached to just the kinase domain of MYO3A (GFP-MYO3AKIN). Coexpression of mchr-MYO3A{Delta}K with either construct resulted in decreased mchr-MYO3A levels at the tips of filopodia and fewer filopodia at the edge of the cell, compared to cells expressing mchr-MYO3A{Delta}K alone. This implies that the kinase domain does not require motor activity to contribute to phosphoregulation of MYO3A, and that MYO3A phosphoregulation may be influencing filopodia initiation. Informatic analyses and structural predictions suggest that the two phosphorylation sites in the motor domain inhibit actin/MYO3A interactions. Taken together, these analyses link MYO3A phosphorylation with the regulation of its ability to create actin protrusions such as filopodia and stereocilia.

Background: Particulate matter (PM) exposure is associated with increased risk and exacerbation of chronic rhinosinusitis (CRS), yet underlying mechanisms remain poorly understood. Methods: Human nasal epithelial cells obtained from ethmoid tissue of CRS (n = 5) and control donors (n = 4) were cultured at an air-liquid interface and exposed to PM. Single-cell RNA sequencing was performed to characterize PM-induced cellular and transcriptional changes. Protein expression, epithelial barrier integrity, cell death, and intracellular PM uptake were evaluated using biochemical, imaging, and ultrastructural approaches. Results: Unsupervised clustering identified seven epithelial cell populations. Gene set analysis revealed baseline enrichment of inflammatory and keratinization pathways and reduced ciliogenesis in CRS compared with controls. Although PM induced inflammation and squamous differentiation in controls, the pathogenic responses were significantly amplified in CRS, including uniquely enhanced IL-1 signaling. Transcriptional changes were validated by ELISA, transepithelial electrical resistance, and immunofluorescence, demonstrating increased inflammation, epithelial barrier disruption, and cell death following PM exposure. Transmission electron microscopy revealed increased intracellular PM within membrane-bound organelles. Pre-treatment with an endocytosis inhibitor rescued PM-induced epithelial barrier dysfunction and inflammation. Conclusion: CRS epithelium exhibits baseline dysfunction that may predispose it to environmental injury. PM exposure both induces CRS-like epithelial changes in controls and exacerbates disease-associated phenotypes.

The search for antimicrobials with a low propensity to select resistance has intensified in response to the global antimicrobial resistance crisis. Norway spruce resin (Picea abies) has long been used in Northern European wound care traditions and has shown broad antimicrobial activity in earlier microbiological studies. In the present study, we evaluated whether prolonged exposure to medical-grade spruce resin promotes reduced susceptibility in clinically relevant bacterial species. A 20-day serial-passage experiment was performed with Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis using sub-inhibitory resin concentrations and broth microdilution readouts at baseline, day 10, and day 20. Resistance development was predefined as a [&ge;]4-fold increase in inhibitory concentration. Baseline inhibitory concentrations were 1.25% for S. aureus, 5.0% for P. aeruginosa, and 2.5% for E. faecalis. After 20 days, inhibitory concentrations were 2.5%, 10.0%, and 2.5%, respectively, corresponding to at most 2-fold changes and remaining below the predefined threshold for resistance development. Validation and vehicle-control arms indicated that these shifts were not attributable to medium transfer or solvent-related bias. These findings suggest that medical-grade Norway spruce resin has a low short-term tendency to select for reduced susceptibility under serial-passage conditions. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/723837v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@160479forg.highwire.dtl.DTLVardef@1fe1e95org.highwire.dtl.DTLVardef@89dec3org.highwire.dtl.DTLVardef@17ff134_HPS_FORMAT_FIGEXP M_FIG C_FIG

Background: Surgical site infection (SSI) is the leading cause of perioperative morbidity following oral cancer surgery, yet the role of the oral microbiota in SSI pathogenesis remains poorly defined. This study prospectively investigated microbiota dynamics in relation to SSI occurrence in patients undergoing resection for oral squamous cell carcinoma (OSCC). Methods: A total of 172 oral swab samples were collected from 45 OSCC patients across four longitudinal time points: baseline (~29 days pre-surgery), immediately pre-surgery (hospital admission), early post-surgery (within 5 days), and late post-surgery (6 to15 days). Bacterial composition was profiled by 16S-rDNA V3-V4 sequencing (172 successfully sequenced samples), and bacterial/human DNA ratios were quantified by qRT-PCR (170 samples evaluated). SSI was assessed within 30 days post-surgery using adapted CDC criteria. Results: Fourteen of 45 patients (31.1%) developed SSI. Younger age was significantly associated with SSI occurrence (median age 53.2 years in SSI group vs. 67.4 years in non-SSI group; p=0.011), with each one-year decrease in age conferring a 7% increased risk. Notably, younger patients presented with larger and more advanced tumors (T3/T4: median age 57.2 vs. 72.9 years for T1/T2; p=0.033), leading to more extensive surgical procedures. Across all 172 samples, surgery induced a marked post-operative reduction in bacterial load and diversity. However, at the late post-surgery time point (collection IV), patients with SSI exhibited significantly higher alpha-diversity compared to non-infected patients (p<0.05 for Observed, Shannon, and Simpson indices). Beta-diversity also differed significantly between groups at this time point (weighted UniFrac, p=0.043). Prevotella and Porphyromonas dominated SSI patients at infection, together accounting for ~40% of reads versus 9.5% in non-infected patients. Among the 172 samples analyzed longitudinally, Aggregatibacter abundance at the early post-surgery time point (collection III) emerged as a significant predictor of subsequent SSI (OR per 1% increase: 1.10; p=0.012), with frequencies >0.044% conferring a 5.7-fold higher risk. Conclusions: Our longitudinal analysis demonstrate that while OSCC surgery profoundly disrupts the oral microbiota, non-SSI patients restore their preoperative profile within 12 days. In contrast, SSI is characterized by persistent dysbiosis dominated by Prevotella and Porphyromonas. Younger patients with advanced tumors are at particular risk. Early post-surgical Aggregatibacter abundance may serve as a novel risk indicator for SSI, potentially enabling timely preventive interventions in high-risk patients.

2.Childhood atopic disease is linked to delayed gut microbiome development and metabolic dysfunction, however microbial drivers remain unclear. To explore microbial correlates of asthma risk during a time of active gut microbiome development, we analyzed stool from 6-month-old infants at high asthma risk (HR) or healthy controls (HC), using Genome-resolved metagenomics (HR=7; HC=12) and untargeted metabolomics (HR=11; HC=15). We recovered 82 bacterial species-level metagenomic-assembled genomes (MAGs). Global Taxonomic composition did not differ by asthma risk. Anticipating that key differences might associate with specific genomes, a machine-learning approach pinpointed Bacteroides cellulosilyticus, Hungatella effluvii, and Enterocloster aldenensis as linked with asthma risk status. All three species were more abundant in HC infants and the B. cellulosilyticus genome was enriched for carbohydrate metabolism genes relative to other MAGs. Metabolomic profiling revealed variance associated with asthma risk (PERMANOVA, R2 =0.069, p=0.016). HR fecal metabolomes were enriched in simple sugars, whereas HC contained more nitrogenous compounds. Integrative genome-metabolic modeling of compounds that significantly differentiate asthma-risk groups revealed risk-dependent interactions with community-encoded metabolic potential (CEP), for arabinose and agmatine, whose fecal concentrations are linked with B. cellulosilyticus and H. effluvii functional traits respectively. These findings suggest that microbial-influenced metabolic differences associate with asthma risk at 6 months, with B. cellulosilyticus and H. effluvii emerging as candidate bacteria influencing this observed metabolic remodeling. 3. Impact statementLeveraging a random forest classifier, we identified three bacterial species (Bacteroides cellulosilyticus, Hungatella effluvii, and Enterocloster aldenensis) as distinguishing features enriched in healthy 6-month old infant microbiomes compared to those at high risk of asthma development (HR). We developed an approach to integrate metabolomics and metagenomic-derived microbiome community encoded potential (CEP) with clinical outcomes to identify fecal metabolites whose concentrations are likely to be influenced by the microbiome. Fecal arabinose concentrations were positively associated with CEP in healthy infants, but not in HR subjects who exhibited elevated concentrations irrespective of CEP. These data implicate microbial activity as a contributor to the concentration of this metabolite in healthy but not HR infants. With a leave-one-out-cross-validation, we identified B. cellulosilyticus as a contributor to fecal arabinose concentrations. Our data indicate that microbial functional deficits in HR infants is associated with altered gut metabolic dysfunction during microbiome maturation. 4. Data summaryDurack et. al [1] is the source of the metabolomics data utilized in this study. The authors confirm that all other supporting data, code and protocols have been provided within the article or through supplementary data files.