Having More Tender Than Swollen Joints Is Associated With Worse Patient-Reported Outcomes in Patients With Early RA.

BACKGROUND/OBJECTIVE: In patients with rheumatoid arthritis (RA), high tender-swollen joint differences (TSJDs) have been associated with worse outcomes. A better understanding of the phenotype and impact of high TSJD on patient-reported outcomes (PROs) in early RA may lead to earlier personalized treatment targeting domains that are important to patients today. Our objectives were to evaluate the impact of TSJD on updated PROs in patients with early RA over 1 year and to determine differences in associations by joint size. METHODS: This longitudinal cohort study followed patients with active, early RA enrolled in the Canadian Early Arthritis Cohort between 2016 and 2022, who completed clinical assessments and PROMIS-29 measures over 1 year. Twenty-eight joint counts were performed and TSJDs calculated. Adjusted associations between TSJD and PROMIS-29 scores were estimated using separate linear-mixed models. Separate analyses of large versus small-joint TJSDs were performed. RESULTS: Patients with early RA (n = 547; 70% female; mean [SD] age, 56 [15] years; mean [SD] symptom duration, 5.3 [2.9] months) were evaluated. A 1-point increase in TSJD was significantly associated with worse PROMIS T-scores in all domains: physical function (adjusted regression coefficient, -0.27; 95% confidence interval [CI], -0.39, -0.15), social participation (adjusted regression coefficient, -0.34; 95% CI, -0.50, -0.19), pain interference (adjusted regression coefficient, 0.49; 95% CI, 0.35, 0.64), sleep problems (adjusted regression coefficient, 0.29; 95% CI, 0.16, 0.43), fatigue (adjusted regression coefficient, 0.34; 95% CI, 0.18, 0.50), anxiety (adjusted regression coefficient, 0.23; 95% CI, 0.08, 0.38), and depression (adjusted regression coefficient, 0.20; 95% CI, 0.06, 0.35). Large-joint TSJD was associated with markedly worse PROs compared with small-joint TSJD. CONCLUSIONS: Elevated TSJD is associated with worse PROs particularly pain interference, social participation, and fatigue. Patients with more tender than swollen joints, especially large joints, may benefit from earlier, targeted therapeutic interventions.

Having More Tender Than Swollen Joints is Associated With Worse Function and Work Impairment in Patients With Early Rheumatoid Arthritis.

OBJECTIVE: Patients with early rheumatoid arthritis (RA) may present with more tender than swollen joints, which can persist. Elevated tender-swollen joint difference (TSJD) is often challenging, because there may be multiple causes and it may contribute to overestimating disease activity. Little is known about the phenotype and impact of TSJDs on patient function. Our objective was to evaluate the impact of TSJD on functional outcomes in early RA and to see whether associations vary by joint size. METHODS: Data were from patients with active, early RA (≤12 months) enrolled in the Canadian Early Arthritis Cohort, who completed assessments of general function (Multidimensional Health Assessment Questionnaire [MDHAQ]), upper extremity (UE) function (Quality of Life in Neurological Disorders [Neuro-QoL] UE scale), and work/activity impairment (Work Productivity and Activity Impairment RA) over their first year of follow-up. A total of 28 joint counts were performed. TSJDs were calculated. Adjusted associations between TSJDs and functional outcomes were estimated in separate multivariable linear mixed effects models. Separate analyses were performed for large- versus small-joint TSJD. RESULTS: Patients (N = 547) were 70% female, mean age 56 (SD 15) years, mean disease duration 5.3 (SD 2.9) months. At baseline, 287 (52%) had TSJD >0 (43% involved large joints and 34% small joints), decreasing to 32% at 12 months. A one-point increase in TSJD was significantly associated with worse function (MDHAQ: adjusted mean change 0.10, 95% confidence interval [CI] 0.08-0.13; Neuro-QoL UE function T score: adjusted mean change -0.59, 95% CI -0.76 to -0.43; and greater work impairment: adjusted mean change 1.95%, 95% CI 0.85%-3.05%). Higher large-joint TSJDs were associated with the worst functional outcomes. CONCLUSION: Having more tender than swollen joints is common in early RA and is associated with worse function, most notably when involving large joints. Early identification and targeted intervention strategies may be needed.

U.S. Breastfeeding Outcomes at the Intersection: Differences in Duration Among Racial and Ethnic Groups With Varying Educational Attainment in a Nationally Representative Sample.

BACKGROUND: As breastfeeding rates in the United States increase, barriers persist for Black, Latine, and low-socioeconomic status household dyads when compared to White and high-socioeconomic status household dyads. Previous breastfeeding disparities research has almost exclusively considered the influence of race, ethnicity, and socioeconomic status separately, although these attributes are not randomly distributed across the population. RESEARCH AIM: To identify breastfeeding duration patterns by race/ethnicity and educational attainment in a nationally representative U.S. National Immunization Survey sample. METHOD: We conducted a cross-sectional, secondary analysis of the U.S. Centers for Disease Control and Prevention's 2020 National Immunization Survey-Child public-use data. To examine breastfeeding and exclusive breastfeeding durations at the intersection of race/ethnicity and educational attainment, we created a 12-item, cross-classified variable using three educational attainment groups and four race/ethnicity groups. We used linear regressions to test these associations. RESULTS: In all, 83% of the sample breastfed. Mean durations of breastfeeding were 7.5 (SE = 1.95) months and exclusive breastfeeding duration was 4.9 (SE = 0.87) months. In adjusted models, multi-race/other high-educational attainment participants had the longest breastfeeding duration by almost 3 weeks (ß: 19.53, 95% CI [5.27, 33.79]), and Black low-educational attainment participants exclusively breastfed for 1 month less than White high-educational attainment participants (ß:-30.23, 95% CI [-40.87, -19.58]). CONCLUSIONS: Examining race/ethnicity and educational attainment together provides an intersectional understanding of breastfeeding outcomes and can inform targeted, culturally appropriate interventions.

Monkeypox Case Investigation - Cook County Jail, Chicago, Illinois, July-August 2022.

Knowledge about monkeypox transmission risk in congregate settings is limited. In July 2022, the Chicago Department of Public Health (CDPH) confirmed a case of monkeypox in a person detained in Cook County Jail (CCJ) in Chicago, Illinois. This case was the first identified in a correctional setting in the United States and reported to CDC during the 2022 multinational monkeypox outbreak. CDPH collaborated with CCJ, the Illinois Department of Public Health (IDPH), and CDC to evaluate transmission risk within the facility. Fifty-seven residents were classified as having intermediate-risk exposures to the patient with monkeypox during the 7-day interval between the patient's symptom onset and his isolation. (Intermediate-risk exposure was defined as potentially being within 6 ft of the patient with monkeypox for a total of ≥3 hours cumulatively, without wearing a surgical mask or respirator, or potentially having contact between their own intact skin or clothing and the skin lesions or body fluids from the patient or with materials that were in contact with the patient's skin lesions or body fluids.) No secondary cases were identified among a subset of 62% of these potentially exposed residents who received symptom monitoring, serologic testing, or both. Thirteen residents accepted postexposure prophylaxis (PEP), with higher acceptance among those who were offered counseling individually or in small groups than among those who were offered PEP together in a large group. Monkeypox virus (MPXV) DNA, but no viable virus, was detected on one surface in a dormitory where the patient had been housed with other residents before he was isolated. Although monkeypox transmission might be limited in similar congregate settings in the absence of higher-risk exposures, congregate facilities should maintain recommended infection control practices in response to monkeypox cases, including placing the person with monkeypox in medical isolation and promptly and thoroughly cleaning and disinfecting spaces where the person has spent time. In addition, officials should provide information to residents and staff members about monkeypox symptoms and transmission modes, facilitate confidential monkeypox risk and symptom disclosure and prompt medical evaluation for symptoms that are reported, and provide PEP counseling in a private setting.

US state policies for Medicaid coverage of donor human milk.

Donor human milk is recommended by the American Academy of Pediatrics for high-risk infants when mother's own milk is absent or insufficient in quantity. Several factors may contribute to the inequitable use of or access to donor human milk, including a limited knowledge of its effects, cost, reimbursement, and regulatory barriers. The American Academy of Pediatrics and the United States Surgeon General have called for investigating barriers that prevent use of donor human milk for high-risk infants and for changes to public policy known to improve availability and affordability. We review the current legislative, regulatory, and economic landscape surrounding donor human milk use in the United States, as well as suggest state- and federal-level solutions to increase access to donor human milk.

The Role of Drosophila CtIP in Homology-Directed Repair of DNA Double-Strand Breaks.

DNA double-strand breaks (DSBs) are a particularly genotoxic type of DNA damage that can result in chromosomal aberrations. Thus, proper repair of DSBs is essential to maintaining genome integrity. DSBs can be repaired by non-homologous end joining (NHEJ), where ends are processed before joining through ligation. Alternatively, DSBs can be repaired through homology-directed repair, either by homologous recombination (HR) or single-strand annealing (SSA). Both types of homology-directed repair are initiated by DNA end resection. In cultured human cells, the protein CtIP has been shown to play a role in DNA end resection through its interactions with CDK, BRCA1, DNA2, and the MRN complex. To elucidate the role of CtIP in a multicellular context, CRISPR/Cas9 genome editing was used to create a DmCtIPΔ allele in Drosophila melanogaster. Using the DSB repair reporter assay direct repeat of white (DR-white), a two-fold decrease in HR in DmCtIPΔ/Δ mutants was observed when compared to heterozygous controls. However, analysis of HR gene conversion tracts (GCTs) suggests DmCtIP plays a minimal role in determining GCT length. To assess the function of DmCtIP on both short (~550 bp) and long (~3.6 kb) end resection, modified homology-directed SSA repair assays were implemented, resulting in a two-fold decrease in SSA repair in both short and extensive end resection requirements in the DmCtIPΔ/Δ mutants compared to heterozygote controls. Through these analyses, we affirmed the importance of end resection on DSB repair pathway choice in multicellular systems, described the function of DmCtIP in short and extensive DNA end resection, and determined the impact of end resection on GCT length during HR.

Intraoperative Cochlear Nerve Monitoring for Vestibular Schwannoma Resection and Simultaneous Cochlear Implantation in Neurofibromatosis Type 2: A Case Series.

BACKGROUND: Neurofibromatosis type 2 (NF2) often results in profound hearing loss and cochlear implantation is an emerging hearing rehabilitation option. However, cochlear implant (CI) outcomes in this population vary, and intraoperative monitoring to predict cochlear nerve viability and subsequent outcomes is not well-established. OBJECTIVE: To review the use of intraoperative electrically evoked cochlear nerve monitoring in patients with NF2 simultaneous translabyrinthine (TL) vestibular schwannoma (VS) resection and cochlear implantation. METHODS: A retrospective review was performed of 3 patients with NF2 that underwent simultaneous TL VS resection and cochlear implantation with electrical auditory brainstem response (eABR) measured throughout tumor resection. Patient demographics, preoperative assessments, surgical procedures, and outcomes were reviewed. RESULTS: Patients 1 and 3 had a reliable eABR throughout tumor removal. Patient 2 had eABR pretumor removal, but post-tumor removal eABR presence could not be reliably determined because of electrical artifact interference. All patients achieved auditory percepts upon CI activation. Patients 1 and 2 experienced a decline in CI performance after 1 yr and after 3 mo, respectively. Patient 3 continues to perform well at 9 mo. Patients 2 and 3 are daily users of their CI. CONCLUSION: Cochlear implantation is attainable in cases of NF2-associated VS resection. Intraoperative eABR may facilitate cochlear nerve preservation during tumor removal, though more data and long-term outcomes are needed to refine eABR methodology and predictive value for this population.

The COVID-19 pandemic from an acute psychiatric perspective: a London psychiatric intensive care unit experience.

The COVID-19 pandemic has put the UK's National Health Service under extreme pressure, and acute psychiatric services have had to rapidly adapt to a new way of working. This editorial describes the experience of a London psychiatric intensive care unit (PICU) where all nine in-patients ultimately tested COVID-19 positive.

Perinatal depressive symptoms and breastfeeding behaviors: A systematic literature review and biosocial research agenda.

BACKGROUND: Breastfeeding is recommended to improve maternal and infant health globally. Depression has been posited to negatively impact breastfeeding, although potential causal and bidirectional pathways between these two phenomena have not been sufficiently characterized. We therefore conducted a systematic review to critically evaluate available evidence on the relationship between perinatal depressive symptoms and breastfeeding behaviors; to identify knowledge gaps and propose a biosocial research agenda to advance our understanding of this topic. METHODS: A systematic search strategy was applied across seven databases. Data were extracted and aggregated using the matrix method to provide a narrative synthesis of findings. RESULTS: Thirty-eight studies from 20 countries spanning 1988 through 2018 fit the inclusion criteria. In general, methods across studies were heterogeneous. Fourteen different tools were used to measure perinatal depressive symptoms. Nearly half the studies did not provide breastfeeding definitions. No studies from low-income countries met inclusion criteria. More than half (63%) of studies demonstrated a negative association between depressive symptoms across the perinatal period and less exclusive breastfeeding and/or shorter breastfeeding durations. LIMITATIONS: Heterogeneity in study design, definitions, assessment tools, and measurement time points limited the comparability of study findings. Causality cannot be assessed. CONCLUSIONS: Available evidence suggests perinatal depressive symptoms negatively associated with breastfeeding exclusivity and duration, which can lead to suboptimal infant nutrition and detrimental impacts on maternal mental and physical health. To better understand this relationship, we propose including consistent operationalization and assessment of depression and breastfeeding globally and concurrent repeated measures of key biological and social factors.

Structural Racism and Barriers to Breastfeeding on Chicagoland's South Side.

For African American (AA) families on Chicagoland's South Side who choose to breastfeed, finding and receiving services needed to reach their goals are difficult. The disparities in breastfeeding support across Chicagoland are symptomatic of inequitable health care access shaped by persisting structural racism. A number of community hospitals that once served AA families by providing easy access to care no longer exist. Recently, South Side obstetric unit and hospital closures have increased. Simultaneously, funding is increasingly competitive for community health organizations and federally qualified health centers. Institutions and agencies that do receive funding or adequately allocate funding to include lactation services cannot address breastfeeding barriers within socioeconomically marginalized communities. The unmet funding needs not only affect breastfeeding families but also impede the growth of a multilevel lactation care workforce. Finally, inconsistencies persist between breastfeeding information provided by lactation providers and delivery team care received in the hospital. Despite these barriers, we believe pathways exist to improve breastfeeding rates among South Side AA communities, such as perinatal home visiting services. Stakeholders must recognize the longstanding effects of structural racism and address the inequitable distribution of perinatal care across Chicagoland. Stakeholders must also place value in and be supportive of lactation care providers and the families they serve through both funding and policies. These changes, in addition to community-level collaboration, can improve breastfeeding rates for AA families on Chicagoland's South Side.

Cochlear Implant Outcomes Following Vestibular Schwannoma Resection: Systematic Review.

OBJECTIVE: Hearing loss remains a significant morbidity for patients with vestibular schwannomas (VS). A growing number of reports suggest audibility with cochlear implantation following VS resection; however, there is little consensus on preferred timing and cochlear implant (CI) performance. DATA SOURCES: A systematic literature search of the Ovid Medline, Embase, Scopus, and clinicaltrails.gov databases was performed on 9/7/2018. PRISMA reporting guidelines were followed. STUDY SELECTION: Included studies reported CI outcomes in an ear that underwent a VS resection. Untreated VSs, radiated VSs, and CIs in the contralateral ear were excluded. DATA EXTRACTION: Primary outcomes were daily CI use and attainment of open-set speech. Baseline tumor and patient characteristics were recorded. Subjects were divided into two groups: simultaneous CI placement with VS resection (Group 1) versus delayed CI placement after VS resection (Group 2). DATA SYNTHESIS: Twenty-nine articles with 93 patients met inclusion criteria. Most studies were poor quality due to their small, retrospective design. Group 1 had 46 patients, of whom 80.4% used their CI on a daily basis and 50.0% achieved open-set speech. Group 2 had 47 patients, of whom 87.2% used their CI on a daily basis and 59.6% achieved open-set speech. Group 2 had more NF2 patients and larger tumors. CI timing did not significantly impact outcomes. CONCLUSIONS: Audibility with CI after VS resection is feasible. Timing of CI placement (simultaneous versus delayed) did not significantly affect performance. Overall, 83.9% used their CI on a daily basis and 54.8% achieved open-set speech.

"If there is no water, we cannot feed our children": The far-reaching consequences of water insecurity on infant feeding practices and infant health across 16 low- and middle-income countries.

OBJECTIVES: Infant feeding plays a critical role in child health and development. Few studies to date have examined the link between household water insecurity and infant feeding, and none in a cross-cultural context. Therefore, we examined the perceived impact of household water insecurity in four domains: breastfeeding, non-breastmilk feeding, caregiver capabilities, and infant health. Our research was conducted as part of the Household Water Insecurity Experiences (HWISE) study. METHODS: We interviewed respondents from 19 sites in 16 low- and middle-income countries (N = 3303) about the link between water insecurity and infant feeding. We then thematically analyzed their open-ended textual responses. In each of the four domains (breastfeeding, non-breastmilk feeding, caregiver capabilities, infant health), we inductively identified cross-cultural metathemes. We analyzed the distribution of themes across sites quantitatively and qualitatively. RESULTS: Water was perceived to directly affect breastfeeding and non-breastmilk feeding via numerous pathways, including timing and frequency of feeding, unclean foods, and reduced dietary diversity. Water was perceived to indirectly affect infant feeding through caregiver capabilities by increasing time demands, exacerbating disease, undernutrition, and mortality, and requiring greater efficacy of caregivers. Respondents made connections between water challenges and infant health, for example, increased risk of infectious diseases, undernutrition, and mortality. CONCLUSIONS: These findings suggest that water presents many, and sometimes unexpected, challenges to infant feeding. By systematically investigating biocultural pathways by which water impacts infant and young child feeding, it will be possible to understand if, and how, water security can be leveraged to improve child nutrition and health.

Tuwongella immobilis gen. nov., sp. nov., a novel non-motile bacterium within the phylum Planctomycetes.

A gram-negative, budding, catalase negative, oxidase positive and non-motile bacterium (MBLW1T) with a complex endomembrane system has been isolated from a freshwater lake in southeast Queensland, Australia. Phylogeny based on 16S rRNA gene sequence analysis places the strain within the family Planctomycetaceae, related to Zavarzinella formosa (93.3 %), Telmatocola sphagniphila (93.3 %) and Gemmata obscuriglobus (91.9 %). Phenotypic and chemotaxonomic analysis demonstrates considerable differences to the type strains of the related genera. MBLW1T displays modest salt tolerance and grows optimally at pH values of 7.5-8.0 and at temperatures of 32-36 °C. Transmission electron microscopy analysis demonstrates the presence of a complex endomembrane system, however, without the typically condensed nucleoid structure found in related genera. The major fatty acids are 16 : 1 ω5c, 16 : 0 and 18 : 0. Based on discriminatory results from 16S rRNA gene sequence analysis, phenotypic, biochemical and chemotaxonomic analysis, MBLW1T should be considered as a new genus and species, for which the name Tuwongella immobilis gen. nov., sp. nov. is proposed. The type strain is MBLW1T (=CCUG 69661T=DSM 105045T).

Nuclear Pore-Like Structures in a Compartmentalized Bacterium.

Planctomycetes are distinguished from other Bacteria by compartmentalization of cells via internal membranes, interpretation of which has been subject to recent debate regarding potential relations to Gram-negative cell structure. In our interpretation of the available data, the planctomycete Gemmata obscuriglobus contains a nuclear body compartment, and thus possesses a type of cell organization with parallels to the eukaryote nucleus. Here we show that pore-like structures occur in internal membranes of G.obscuriglobus and that they have elements structurally similar to eukaryote nuclear pores, including a basket, ring-spoke structure, and eight-fold rotational symmetry. Bioinformatic analysis of proteomic data reveals that some of the G. obscuriglobus proteins associated with pore-containing membranes possess structural domains found in eukaryote nuclear pore complexes. Moreover, immunogold labelling demonstrates localization of one such protein, containing a ß-propeller domain, specifically to the G. obscuriglobus pore-like structures. Finding bacterial pores within internal cell membranes and with structural similarities to eukaryote nuclear pore complexes raises the dual possibilities of either hitherto undetected homology or stunning evolutionary convergence.

Validation of picogram- and femtogram-input DNA libraries for microscale metagenomics.

High-throughput sequencing libraries are typically limited by the requirement for nanograms to micrograms of input DNA. This bottleneck impedes the microscale analysis of ecosystems and the exploration of low biomass samples. Current methods for amplifying environmental DNA to bypass this bottleneck introduce considerable bias into metagenomic profiles. Here we describe and validate a simple modification of the Illumina Nextera XT DNA library preparation kit which allows creation of shotgun libraries from sub-nanogram amounts of input DNA. Community composition was reproducible down to 100 fg of input DNA based on analysis of a mock community comprising 54 phylogenetically diverse Bacteria and Archaea. The main technical issues with the low input libraries were a greater potential for contamination, limited DNA complexity which has a direct effect on assembly and binning, and an associated higher percentage of read duplicates. We recommend a lower limit of 1 pg (∼100-1,000 microbial cells) to ensure community composition fidelity, and the inclusion of negative controls to identify reagent-specific contaminants. Applying the approach to marine surface water, pronounced differences were observed between bacterial community profiles of microliter volume samples, which we attribute to biological variation. This result is consistent with expected microscale patchiness in marine communities. We thus envision that our benchmarked, slightly modified low input DNA protocol will be beneficial for microscale and low biomass metagenomics.

Migration and common mental disorder: an improvement in mental health over time?

Global migration is reaching record high levels and UK migrant groups comprise an increasing proportion of the total population. The migratory process causes stress that can affect mental health. There is limited consistent empirical evidence of a longitudinal nature to explain the association between migration and mental health. This review aims to examine the evidence of a relationship between migration and common mental disorder (CMD) amongst migrants over time. A comprehensive search of medical and psychiatric databases for global quantitative empirical studies investigating incidence of CMD amongst adult migrants from 1975 to July 2012 was conducted. Declines in rates of CMD amongst migrants over time were reported by two thirds of the 18 studies reviewed, less than one third of which were statistically significant. On the contrary, three studies showed an increased rate of CMD, one statistically significant. Individual psychological resources, social support, the acculturation process, cultural variations and time since relocation are identified as statistically significant protective factors against the development of CMD amongst migrants. New enlightening points include the significant impact of varying patterns of psychological distress, of which negative is the most adverse for CMD. Migration is an extremely complex process. Further clarification is needed to gain deeper understanding of the relationship between migration and CMD to address contradictions in the literature and health inequalities amongst migrants.

Shining a light on dark sequencing: characterising errors in Ion Torrent PGM data.

The Ion Torrent Personal Genome Machine (PGM) is a new sequencing platform that substantially differs from other sequencing technologies by measuring pH rather than light to detect polymerisation events. Using re-sequencing datasets, we comprehensively characterise the biases and errors introduced by the PGM at both the base and flow level, across a combination of factors, including chip density, sequencing kit, template species and machine. We found two distinct insertion/deletion (indel) error types that accounted for the majority of errors introduced by the PGM. The main error source was inaccurate flow-calls, which introduced indels at a raw rate of 2.84% (1.38% after quality clipping) using the OneTouch 200 bp kit. Inaccurate flow-calls typically resulted in over-called short-homopolymers and under-called long-homopolymers. Flow-call accuracy decreased with consecutive flow cycles, but we also found significant periodic fluctuations in the flow error-rate, corresponding to specific positions within the flow-cycle pattern. Another less common PGM error, high frequency indel (HFI) errors, are indels that occur at very high frequency in the reads relative to a given base position in the reference genome, but in the majority of instances were not replicated consistently across separate runs. HFI errors occur approximately once every thousand bases in the reference, and correspond to 0.06% of bases in reads. Currently, the PGM does not achieve the accuracy of competing light-based technologies. However, flow-call inaccuracy is systematic and the statistical models of flow-values developed here will enable PGM-specific bioinformatics approaches to be developed, which will account for these errors. HFI errors may prove more challenging to address, especially for polymorphism and amplicon applications, but may be overcome by sequencing the same DNA template across multiple chips.

High-pressure freezing/freeze substitution and transmission electron microscopy for characterization of metal oxide nanoparticles within sunscreens.

AIMS: To date, the description of a single, suitable method to observe in detail metal oxide nanoparticles in situ within sunscreens is currently lacking, despite growing concern as to how they interact with humans. This study explores the usefulness of transmission electron microscopy to characterize the nanoparticles in sunscreens. MATERIALS & METHODS: High-pressure freezing then freeze substitution was used to prepare resin-embedded commercial sunscreen samples, and ultrathin sections of these were observed with transmission electron microscopy. Conventional room temperature processing for resin embedding was also trialed. RESULTS: High-pressure frozen/freeze substituted samples provided clear visualization of the size and shape of the nanoparticles and agglomerates and allowed further characterization of the composition and crystal form of the metal oxides, while conventionally processed chemically fixed samples were subject to distribution/agglomeration artifacts. CONCLUSION: Transmission electron microscopy of high-pressure frozen/freeze substituted samples is an ideal method to completely observe metal oxide nanoparticles in situ in sunscreens.

Gold nanoparticle penetration and reduced metabolism in human skin by toluene.

PURPOSE: To measure penetration and metabolic effects of ion-stabilized, polar, 15 nm gold nanoparticles in aqueous solution (AuNP-Aq) and sterically stabilized, non-polar, 6 nm gold nanoparticles in toluene (AuNP-TOL) on excised human skin. METHODS: Gold nanoparticles were characterized with dynamic light scattering and transmission electron microscopy (TEM). Skin penetration studies were done on frozen or fresh excised skin using static Franz diffusion cells. Viable treated skin was assessed by dermoscopy, reflectance confocal microscopy (RCM), multiphoton tomography (MPT) with fluorescence lifetime imaging microscopy (FLIM), and TEM. RESULTS: Dermoscopy and RCM showed large aggregates in the furrows of AuNP-Aq-treated skin. Treatment of thawed and viable skin only showed enhanced permeability to nanoparticles in the AuNP-TOL group with MPT and FLIM imaging to stratum spinosum of epidermis. TEM analysis revealed gold nanoparticles within AuNP-treated stratum corneum. FLIM analysis of NAD(P)H showed a significant decrease in total NAD(P)H in all toluene-treated groups. CONCLUSIONS: Gold nanoparticles, 15 nm, in aqueous solution aggregated on the skin surface. Toluene treatment eliminated skin metabolism; skin treated with toluene/gold nanoparticles (6 nm) for 24 h, but not at 4 h, showed increased nanoparticle permeability. These results are of value to nanotoxicology.

Time-correlated single photon counting for simultaneous monitoring of zinc oxide nanoparticles and NAD(P)H in intact and barrier-disrupted volunteer skin.

PURPOSE: There is a lack of relevant, non-animal alternatives for assessing exposure and toxicity of nanoparticle-containing cosmetics, e.g. sunscreens. Our goal was to evaluate timecorrelated single photon counting (TCSPC) for simultaneous monitoring of zinc oxide nanoparticles (ZnO-NP) and the metabolic state of volunteer skin. METHODS: We separated the fluorescence lifetime signatures of endogenous fluorophore signals (i.e. nicotinamide adenine dinucleotide phosphate, NAD(P)H and keratin) and the ZnO-NP signal using advanced TCSPC to simultaneously determine ZnO-NP penetration profiles and NAD(P)H changes in subjects with altered barrier function, including tape-stripped skin and in psoriasis or atopic dermatitis lesions. RESULTS: We detected no ZnO-NP penetration into viable human skin in any group. ZnO-NP signal was significantly increased (p < 0.01) on the surface of tape-stripped and lesional skin after 4 and 2 h of treatment, respectively. Free NAD(P)H signal significantly increased in tape-stripped viable epidermis treated for 4 h of ZnO-NP compared to vehicle control. No significant NAD(P)H changes were noted in the lesional study. CONCLUSION: TCSPC techniques enabled simultaneous, real-time quantification of ZnO-NP concentration and NAD(P)H via non-invasive imaging in the stratum corneum and viable epidermis of volunteers.