The NeST long ncRNA controls microbial susceptibility and epigenetic activation of the interferon-γ locus.

Long noncoding RNAs (lncRNAs) are increasingly appreciated as regulators of cell-specific gene expression. Here, an enhancer-like lncRNA termed NeST (nettoie Salmonella pas Theiler's [cleanup Salmonella not Theiler's]) is shown to be causal for all phenotypes conferred by murine viral susceptibility locus Tmevp3. This locus was defined by crosses between SJL/J and B10.S mice and contains several candidate genes, including NeST. The SJL/J-derived locus confers higher lncRNA expression, increased interferon-γ (IFN-γ) abundance in activated CD8(+) T cells, increased Theiler's virus persistence, and decreased Salmonella enterica pathogenesis. Transgenic expression of NeST lncRNA alone was sufficient to confer all phenotypes of the SJL/J locus. NeST RNA was found to bind WDR5, a component of the histone H3 lysine 4 methyltransferase complex, and to alter histone 3 methylation at the IFN-γ locus. Thus, this lncRNA regulates epigenetic marking of IFN-γ-encoding chromatin, expression of IFN-γ, and susceptibility to a viral and a bacterial pathogen.

Polarized transilluminating dermoscopy: Bedside trichoscopic diagnosis of trichothiodystrophy.

Trichothiodystrophy is a rare autosomal recessive disorder resulting in a broad range of systemic abnormalities. Polarizing microscopy of the hair reveals the pathognomic "tiger tail" of alternating light and dark bands, but the need for a microscope prevents rapid bedside diagnosis. We describe a new technique for the bedside diagnosis of trichothiodystrophy using a handheld polarizing dermatoscope, precluding the need for microscopic examination.

LncRNA-HIT Functions as an Epigenetic Regulator of Chondrogenesis through Its Recruitment of p100/CBP Complexes.

Gene expression profiling in E 11 mouse embryos identified high expression of the long noncoding RNA (lncRNA), LNCRNA-HIT in the undifferentiated limb mesenchyme, gut, and developing genital tubercle. In the limb mesenchyme, LncRNA-HIT was found to be retained in the nucleus, forming a complex with p100 and CBP. Analysis of the genome-wide distribution of LncRNA-HIT-p100/CBP complexes by ChIRP-seq revealed LncRNA-HIT associated peaks at multiple loci in the murine genome. Ontological analysis of the genes contacted by LncRNA-HIT-p100/CBP complexes indicate a primary role for these loci in chondrogenic differentiation. Functional analysis using siRNA-mediated reductions in LncRNA-HIT or p100 transcripts revealed a significant decrease in expression of many of the LncRNA-HIT-associated loci. LncRNA-HIT siRNA treatments also impacted the ability of the limb mesenchyme to form cartilage, reducing mesenchymal cell condensation and the formation of cartilage nodules. Mechanistically the LncRNA-HIT siRNA treatments impacted pro-chondrogenic gene expression by reducing H3K27ac or p100 activity, confirming that LncRNA-HIT is essential for chondrogenic differentiation in the limb mesenchyme. Taken together, these findings reveal a fundamental epigenetic mechanism functioning during early limb development, using LncRNA-HIT and its associated proteins to promote the expression of multiple genes whose products are necessary for the formation of cartilage.

A long noncoding RNA maintains active chromatin to coordinate homeotic gene expression.

The genome is extensively transcribed into long intergenic noncoding RNAs (lincRNAs), many of which are implicated in gene silencing. Potential roles of lincRNAs in gene activation are much less understood. Development and homeostasis require coordinate regulation of neighbouring genes through a process termed locus control. Some locus control elements and enhancers transcribe lincRNAs, hinting at possible roles in long-range control. In vertebrates, 39 Hox genes, encoding homeodomain transcription factors critical for positional identity, are clustered in four chromosomal loci; the Hox genes are expressed in nested anterior-posterior and proximal-distal patterns colinear with their genomic position from 3' to 5'of the cluster. Here we identify HOTTIP, a lincRNA transcribed from the 5' tip of the HOXA locus that coordinates the activation of several 5' HOXA genes in vivo. Chromosomal looping brings HOTTIP into close proximity to its target genes. HOTTIP RNA binds the adaptor protein WDR5 directly and targets WDR5/MLL complexes across HOXA, driving histone H3 lysine 4 trimethylation and gene transcription. Induced proximity is necessary and sufficient for HOTTIP RNA activation of its target genes. Thus, by serving as key intermediates that transmit information from higher order chromosomal looping into chromatin modifications, lincRNAs may organize chromatin domains to coordinate long-range gene activation.

Use of Porcine Xenografts in Dermatology Surgery: The Mayo Clinic Experience.

BACKGROUND: Knowledge regarding the use of xenografts in cutaneous surgery is limited. OBJECTIVE: We sought to better understand the utility, outcomes, and complications of porcine xenograft applications in cutaneous surgery. METHODS AND MATERIALS: A single center, retrospective study of patients with porcine xenograft applications was completed. Characteristics of tumors, surgical procedures, resulting wound beds, follow-up care, and final length of follow-up were determined, and statistical analysis was conducted. RESULTS: Of 225 porcine xenograft placements in 220 patients, the majority of tumors were nonmelanoma skin cancers (89%) and similarly divided between the head (excepting nose/ear), nose, ear, and extremities. Both Mohs and standard excision resulted in a 5.7 cm mean area of surgical defect, with the majority closed by porcine xenograft only (84.1%), and healing by secondary intention (97.3%). The area of surgical defect and topical antibiotics contributed to increased length of time to final follow-up. CONCLUSION: The data represent the largest series of biologic dressings in cutaneous surgery and demonstrate the applicability and safety of porcine xenografts. We recommend consideration of porcine xenografts in the appropriate clinical context, to augment secondary intention.

Results of Patch Testing to Botanicals: Review of the Mayo Clinic Experience Over 2 Decades (1997-2017).

Background: Botanicals are increasingly incorporated into skincare products. Although allergic contact dermatitis due to botanicals is recognized, data describing the prevalence of positive patch tests to botanicals are sparse. Objective: To report the Mayo Clinic experience of patch testing to selected botanical products in the standard, extended standard, fragrance, and plant series. Methods: IRB-approved retrospective study of the Mayo Clinic experience with patch testing to botanicals from 1997 to 2017. Results: In total, 12,169 people were patch tested to botanicals in the standard, extended standard, fragrance, and plant series; 4032 were men and 8137 were women. The mean age of the population tested was 54 (standard deviation 17.7) years. Almost 11% (1320/12,169) of the patch-tested population exhibited positive reactions to at least 1 botanical agent. Myroxylon pereirae resin 25% was the most common positive allergen in the series. Patients who had positive reactions to at least 1 botanical agent were more (19.8%) likely to have a positive reaction to at least 1 additional botanical than those patients who did not have any positive tests. Most patients presented with generalized involvement (334) or involvement of the hands (284) or face (232). Conclusion: Physicians should be aware of the high prevalence of allergic contact dermatitis and patch test positivity associated with botanical products.

Pediatric Patch Testing at Mayo Clinic Between 2016 and 2020.

Background: Allergic contact dermatitis (ACD) is a common condition within the pediatric population. Patch testing is an important way to identify relevant allergens. Objective: To provide an update of the common contact allergens seen in children based on patch testing data at our institution from 2016 to 2020. Methods: We performed a retrospective analysis of patch test data from children aged 1-18 years from 2016 to 2020 at Mayo Clinic. Reaction rates were compared to the rates reported by the Pediatric Contact Dermatitis Registry (PCDR). Results: One hundred ninety-two children aged 1-18 were patch tested to various allergens. A total of 15,457 allergens were tested, with 291 positive tests. The top 5 allergens with highest positive reaction rates were hydroperoxides of linalool, hydroperoxides of limonene, methylisothiazolinone, nickel, and cobalt. Seven of the top 38 allergens with the highest reaction rates are not currently included in the Mayo Clinic Pediatric Patch Test Series, and 11 are not currently included in the Pediatric Baseline Series (as developed by the Pediatric Contact Dermatitis Workgroup). Conclusions: Patch testing is a useful tool to diagnose children with ACD. With new products and exposures, there is an opportunity to expand current pediatric patch testing series.

Allergic contact dermatitis of the eyelids: An interdisciplinary review.

PURPOSE: A review of the published literature on the pathogenesis and treatment of eyelid allergic contact dermatitis and ocular surface involvement. METHODS: Literature search of MEDLINE (Ovid) was conducted using for allergic contact dermatitis and disease of the eyelid or periorbital skin. Dates included in search criteria were from January 1, 2010 to January 12, 2023. 120 articles were reviewed by at least two authors. RESULTS: Allergic eyelid contact dermatitis(ACD) is a Type IV hypersensitivity reaction to chemical exposure of sensitized eyelid skin. Most patients improve with avoidance strategies. Understanding chemicals that may trigger eyelid ACD, identifying allergens with patch testing, and use of topical steroids can help patients with this challenging disease. CONCLUSIONS: Recalcitrant allergic eyelid dermatitis can be addressed by an interdisciplinary team and avoidance strategies based on patch testing.

Trends in Patch Testing With the Mayo Clinic Standard Series, 2017-2021.

Background: Patch testing to a standard series is used to identify culprit allergens in patients with contact dermatitis. The reaction rates evolve over time based on trends in cutaneous exposures by the general population. Objective: The aim of this study was to analyze the patch test results of the Mayo Clinic standard series in patients tested from 2017 to 2021. Methods: The patch test reactions of standard series allergens tested from 2017 to 2021 were retrospectively reviewed and compared with the results of our prior report from 2011 to 2015 as well as the North American Contact Dermatitis Group (NACDG) report from 2017 to 2018. Results: Of 2667 patients tested, 1683 (63.1%) had at least 1 positive reaction. The 15 allergens with the highest reaction rates were hydroperoxides of linalool 1%, nickel (II) sulfate hexahydrate, methylisothiazolinone, Myroxylon pereirae resin, hydroperoxides of linalool 0.5%, methyldibromo glutaronitrile, neomycin sulfate, cobalt (II) chloride hexahydrate, fragrance mix I, benzalkonium chloride, bacitracin, hydroperoxides of limonene, methylchloroisothiazolinone/methylisothiazolinone, p-phenylenediamine, and textile dye mix. Twelve (80%) of these allergens were also in the top 15 of the most recent NACDG report. Conclusions: Hydroperoxides of linalool and hydroperoxides of limonene are new allergens that have been added to our standard series. These are associated with high reaction rates.

Systematic Identification of Copositivity Groups in Standard Series Patch Testing Through Hierarchical Clustering.

Importance: Patients are frequently copositive for multiple allergens simultaneously, either due to chemical similarity or simultaneous sensitization. A better understanding of copositivity groups would help guide contact avoidance. Objective: To use patient data to systematically determine copositivity groups in the Mayo Clinic Standard Series. Design, Setting, and Participants: In this retrospective cross-sectional analysis, the Mayo Clinic patch test database was queried for pairwise copositivity rates in the 80 allergen Mayo Clinic Standard Series between 2012 and 2021. Data were collected from 3 tertiary care sites of the Mayo Clinic Contact Dermatitis Group and a total of 5943 patients were included, comprising all patients undergoing patch testing to the Mayo Clinic Standard Series allergens. Main Outcomes and Measures: Copositivity rates between every 2 allergens in the 80-allergen Mayo Clinic Standard Series were estimated. After background correction, copositivity rates were analyzed using unsupervised hierarchical clustering to systematically identify copositivity groups in an unbiased manner. Results: Overall, 394 921 total patches were applied to 5943 patients (4164 [70.1%] women, 1776 [29.9%] men, with a mean [SD] age of 52.3 [18.8] years ), comprising 9545 positive reactions. After background correction based on overall positivity rates, hierarchical clustering revealed distinct copositivity groups. Many were supported by prior literature, including formaldehyde releasers, cobalt-nickel-potassium dichromate, acrylates, 3-dimethylaminopropylamine-amidoamine-oleamidopropyl dimethylamine, alkyl glucosides, budesonide-hydrocortisone-17-butyrate, certain fragrances, compositae-sesquiterpene lactone mix, mercapto mix-mercaptobenzothiazole, carba mix-thiuram mix, and disperse orange-p-phenylenediamine. However, novel associations were also found, including glutaraldehyde-sorbitan sesquioleate, benzalkonium chloride-neomycin-bacitracin, bronopol-methylchloroisothiazolinone-methylisothiazolinone, and benzoic acid-iodopropynyl butylcarbamate. Conclusions and Relevance: This retrospective cross-sectional analysis found that copositivity rates varied between allergens; allergens with extremely high positivity rates demonstrated nonspecific copositivity to multiple other allergens. Background correction based on positivity rates followed by hierarchical clustering confirmed prior known copositivity groups, contaminants and/or excipients leading to copositivity, and novel associations to guide contact avoidance.

Evolutionary genomics of host-use in bifurcating demes of RNA virus phi-6.

BACKGROUND: Viruses are exceedingly diverse in their evolved strategies to manipulate hosts for viral replication. However, despite these differences, most virus populations will occasionally experience two commonly-encountered challenges: growth in variable host environments, and growth under fluctuating population sizes. We used the segmented RNA bacteriophage ϕ6 as a model for studying the evolutionary genomics of virus adaptation in the face of host switches and parametrically varying population sizes. To do so, we created a bifurcating deme structure that reflected lineage splitting in natural populations, allowing us to test whether phylogenetic algorithms could accurately resolve this 'known phylogeny'. The resulting tree yielded 32 clones at the tips and internal nodes; these strains were fully sequenced and measured for phenotypic changes in selected traits (fitness on original and novel hosts). RESULTS: We observed that RNA segment size was negatively correlated with the extent of molecular change in the imposed treatments; molecular substitutions tended to cluster on the Small and Medium RNA chromosomes of the virus, and not on the Large segment. Our study yielded a very large molecular and phenotypic dataset, fostering possible inferences on genotype-phenotype associations. Using further experimental evolution, we confirmed an inference on the unanticipated role of an allelic switch in a viral assembly protein, which governed viral performance across host environments. CONCLUSIONS: Our study demonstrated that varying complexities can be simultaneously incorporated into experimental evolution, to examine the combined effects of population size, and adaptation in novel environments. The imposed bifurcating structure revealed that some methods for phylogenetic reconstruction failed to resolve the true phylogeny, owing to a paucity of molecular substitutions separating the RNA viruses that evolved in our study.

A Retrospective Review of Late Delayed Positive Patch Testing Greater Than Day 8 at Mayo Clinic From 2001 to 2020.

BACKGROUND: Patch tests are read between days 5 and 7, because most hypersensitivity reactions occur within 7 days. Later reactions can occur after day 8, which may be missed. OBJECTIVE: The aim of the study was to review all late delayed positive (LDP) reactions that have occurred after day 8 at Mayo Clinic from 2001 to 2020. METHODS: Mayo Clinic records were reviewed for patients who had patch test readings performed at greater than day 8. Late delayed positive reactions were defined as any patch tests that were initially negative from days 4 to 7 yet became positive after day 8. RESULTS: Two hundred seventy-four patients developed 439 LDPs to 89 allergens. Fourteen allergens had LDPs in at least 2% of patients: gold (gold sodium thiosulfate-3 concentrations, gold chloride, potassium dicyanoaurate), cobalt (cobalt sulfate, cobalt chloride hexahydrate), beryllium, palladium, acrylates (2-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate), dodecyl gallate, and gentamycin. Late delayed positive reactions to gold allergens were the most frequent reactions. Up to 90% of relevant gold allergen LDPs were positive by day 15. CONCLUSIONS: Positive patch test readings after day 8 are uncommon, but allergens most likely to be positive are metals (gold, cobalt, palladium, beryllium), acrylates, dodecyl gallate, and gentamycin. Gold allergens showed the highest LDP rates and relevance, with most reactions occurring by day 15.

Reevaluating Corticosteroid Classification Models in Patient Patch Testing.

Importance: Individuals with allergic contact dermatitis to one topical corticosteroid may also react to other corticosteroids. Corticosteroid classification models have been proposed to predict such copositivity, recommend representative screening corticosteroids, and guide allergen avoidance. Objective: To use patient data to determine copositivity patterns between corticosteroids and evaluate against previous corticosteroid classification models. Design, Setting, and Participants: This qualitative study included a retrospective analysis of the Mayo Clinic Contact Dermatitis Group corticosteroid patch test data from 2010 to 2019. Among patients undergoing patch testing with the Mayo Clinic's standard or steroid series who consented to research participation, 5637 patients were included in the analysis. Copositivity rates were determined between corticosteroids and analyzed by hierarchical clustering for comparison to previous classification models. Main Outcomes and Measures: The frequency of patch test positivity to each of the analyzed corticosteroids was noted and compared with previously published patch test positivity rates. Copositivity rates between each pair of corticosteroids were determined, and overall copositivity patterns were analyzed and evaluated against known steroid classes. Results: A total of 49 472 individual patches were applied to 5637 patients, testing 18 corticosteroids. Patch test positivity rates ranged between 0.3% and 4.7%. The fluocinonide positivity rate corresponded to the highest copositivity rate with other corticosteroids (mean [SD], 50.7% [26.1%]). Tixocortol-21-pivalate, 0.1%, and tixocortol-21-pivalate, 1%, positivity rates corresponded to the lowest copositivity rates (mean [SD], 4.1% [1.7%] and 3.6% [1.4%], respectively). Hierarchical clustering elucidated patterns that did not support previous corticosteroid classification models. Conclusions and Relevance: In this qualitative study, copositivity rates were variable between corticosteroids, and overall patch test positivity for allergy to topical corticosteroids was rare. Previously published corticosteroid classifications are not supported by real patient-derived data and may not be accurate in predicting corticosteroid copositivity.

Treatment of Hydroxyurea-Induced Ulcers With Timolol.

This report evaluates the use of timolol in 2 patients with long-term hydroxyurea use and lower-extremity ulcers resistant to other treatments.