Changing climatic controls on the greenhouse gas balance of thermokarst bogs during succession after permafrost thaw.

Permafrost thaw in northern peatlands causes collapse of permafrost peat plateaus and thermokarst bog development, with potential impacts on atmospheric greenhouse gas exchange. Here, we measured methane and carbon dioxide fluxes over 3 years (including winters) using static chambers along two permafrost thaw transects in northwestern Canada, spanning young (~30 years since thaw), intermediate and mature thermokarst bogs (~200 years since thaw). Young bogs were wetter, warmer and had more hydrophilic vegetation than mature bogs. Methane emissions increased with wetness and soil temperature (40 cm depth) and modelled annual estimates were greatest in the young bog during the warmest year and lowest in the mature bog during the coolest year (21 and 7 g C-CH4 m-2 year-1, respectively). The dominant control on net ecosystem exchange (NEE) in the mature bog (between +20 and -54 g C-CO2 m-2 year-1) was soil temperature (5 cm), causing net CO2 loss due to higher ecosystem respiration (ER) in warmer years. In contrast, wetness controlled NEE in the young and intermediate bogs (between +55 and -95 g C-CO2 m-2 year-1), where years with periodic inundation at the beginning of the growing season caused greater reduction in gross primary productivity than in ER leading to CO2 loss. Winter fluxes (November-April) represented 16% of annual ER and 38% of annual CH4 emissions. Our study found NEE of thermokarst bogs to be close to neutral and rules out large CO2 losses under current conditions. However, high CH4 emissions after thaw caused a positive net radiative forcing effect. While wet conditions favouring high CH4 emissions only persist for the initial young bog period, we showed that continued climate warming with increased ER, and thus, CO2 losses from the mature bog can cause net positive radiative forcing which would last for centuries after permafrost thaw.

How Dermatologic Surgeons Decide to Proceed with Surgery for Nonmelanoma Skin Cancer When Site Identification is Initially Uncertain: A Nationwide, Multicenter, Prospective Study.

BACKGROUND: Few studies show how dermatologic surgeons manage problems with site identification. OBJECTIVE: To estimate frequency and characterize management of skin cancer treated by surgery when the anatomic location of the tumor is in question. METHODS: Nationwide, prospective, multi-site cohort study. RESULTS: Among 17,076 cases at 22 centers, 98 (0.60%) were lesions in question (LIQ) for which site identification was initially uncertain, with these more often in patients who were male, older, and biopsied more than 30 days ago. Surgeons employed on average 5.0 (95% CI: 4.61-5.39) additional techniques to confirm the site location, with common approaches including: re-checking available documentation (90 lesions, 92%); performing an expanded physical examination (89 lesions, 91%); and asking the patient to point using a mirror (61 lesions, 62%). In 15%, photographs were requested from the biopsying provider, and also in 15%, frozen section biopsies were obtained. In 10%, the referring physician was contacted. Eventually, surgeons succeeded in definitively identifying 82% (80/98) of initially uncertain sites, with the remaining 18% (18/98) postponed. Most postponed surgeries were at non-facial sites. LIMITATIONS: Sites were academic centers. CONCLUSIONS: When the anatomic location of the tumor is uncertain, dermatologic surgeons use multiple methods to identify the site, and sometimes cases are postponed.

A study of collagen refractility in dermatofibroma and dermatofibrosarcoma protuberans using diffractive microscopy.

BACKGROUND: Diffractive microscopy creates contrast within samples that are otherwise uniform under bright light. This technique can highlight subtle differences in refractive indices within birefringent samples containing varying amounts of mature collagen. Dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP) possess differences in their mature collagen content and, therefore, may be distinguishable using diffractive microscopy. METHODS: Two hundred forty-two DF and 85 DFSP hematoxylin-eosin (H&E)-stained specimens were analyzed using diffractive microscopy. Data regarding the distribution pattern and strength of refractility was recorded. RESULTS: DFSP was more frequently found to be focally, weakly, or non-refractile (82.9%; n = 68) under diffractive microscopy, while DF more often showed diffusely bright refractility (52.9%; n = 128). DFSP samples with diffuse refractility in portions of the lesion (17.1%; n = 14) also exhibited a unique checkerboard pattern distinct from that which was seen in DF samples. CONCLUSIONS: The absence of diffuse refractility was more closely associated with DFSP, as was the presence of a unique checkerboard diffraction pattern. Despite high sensitivity (Sn = 82.9%), absent refractility was not a specific test (Sp = 52.9%), with 47.1% (n = 114) of DF samples sharing this feature. The distinction between DF and DFSP is often diagnosed using H&E alone. In difficult cases, examination of collagen under diffractive microscopy may be useful in distinguishing DFSP from DF and provide an alternative cost-effective tool to immunohistochemical staining.

Climate warming has direct and indirect effects on microbes associated with carbon cycling in northern lakes.

Northern lakes disproportionately influence the global carbon cycle, and may do so more in the future depending on how their microbial communities respond to climate warming. Microbial communities can change because of the direct effects of climate warming on their metabolism and the indirect effects of climate warming on groundwater connectivity from thawing of surrounding permafrost, especially at lower landscape positions. Here we used shotgun metagenomics to compare the taxonomic and functional gene composition of sediment microbes in 19 peatland lakes across a 1600-km permafrost transect in boreal western Canada. We found microbes responded differently to the loss of regional permafrost cover than to increases in local groundwater connectivity. These results suggest that both the direct and indirect effects of climate warming, which were respectively associated with loss of permafrost and subsequent changes in groundwater connectivity interact to change microbial composition and function. Archaeal methanogens and genes involved in all major methanogenesis pathways were more abundant in warmer regions with less permafrost, but higher groundwater connectivity partly offset these effects. Bacterial community composition and methanotrophy genes did not vary with regional permafrost cover, and the latter changed similarly to methanogenesis with groundwater connectivity. Finally, we found an increase in sugar utilization genes in regions with less permafrost, which may further fuel methanogenesis. These results provide the microbial mechanism for observed increases in methane emissions associated with loss of permafrost cover in this region and suggest that future emissions will primarily be controlled by archaeal methanogens over methanotrophic bacteria as northern lakes warm. Our study more generally suggests that future predictions of aquatic carbon cycling will be improved by considering how climate warming exerts both direct effects associated with regional-scale permafrost thaw and indirect effects associated with local hydrology.

Comparative effectiveness of ice packs versus topical lidocaine-prilocaine mixture for pain control in laser hair removal of the axilla: A rater-blinded randomized controlled trial.

BACKGROUND: Laser hair removal is associated with moderate acute pain. OBJECTIVE: To compare effectiveness of ice pack to topical lidocaine-prilocaine for pain reduction during axillary laser hair removal. METHODS: Participants were randomly assigned to receive topical anesthetic to one axilla and ice packs to the other before each of 3, monthly 810 nm diode laser sessions. The primary endpoint was participant-reported pain on the visual analog scale (VAS) immediately following and 5 minutes after laser session. Posttreatment erythema, overall edema, and perifollicular edema were assessed by 2 blinded photoraters. Skin temperatures, patient preferences, and adverse events were recorded. RESULTS: Eighty-eight of 90 (98%) planned laser treatments were delivered and randomized. Participants reported higher VAS scores immediately after laser treatment with lidocaine-prilocaine compared to ice (P = .03). Five minutes after, participants reported higher VAS scores with ice (P = .03). After 53 of the 88 treatments (60.2%), participants reported preferring ice (P = .055). No serious adverse events were reported. LIMITATIONS: All participants were Caucasian or Asian with Fitzpatrick skin type I to III and coarse dark axillary hair, which may limit generalizability. CONCLUSIONS: While pain control with ice and topical anesthesia is associated with time after treatment, the 2 modalities do not differ in terms of degree of pain reduction associated with axillary laser hair removal.

Pain of local anesthetic injection of lidocaine during subsequent stages of Mohs micrographic surgery: A multicenter prospective cohort study.

BACKGROUND: Patients awake during staged cutaneous surgery procedures may experience procedure-related pain. OBJECTIVE: To determine whether the level of pain associated with local anesthetic injections prior to each Mohs stage increases with subsequent Mohs stages. METHODS: Multicenter longitudinal cohort study. Patients rated pain (visual analog scale: 1-10) after anesthetic injection preceding each Mohs stage. RESULTS: Two hundred fifty-nine adult patients presenting for Mohs who required multiple Mohs stages at 2 academic medical centers were enrolled; 330 stages were excluded due to complete anesthesia from prior stages, and 511 stages were analyzed. Mean visual analog scale pain ratings were nominally but not significantly different for subsequent stages of Mohs surgery (stage 1: 2.5; stage 2: 2.5; stage 3: 2.7: stage 4:2.8: stage 5: 3.2; P = .770). Between 37% and 44% experienced moderate pain, and 9.5% and 12.5% severe pain, during first as versus subsequent stages (P > .05) LIMITATIONS: Both academic centers were in urban areas. Pain rating is inherently subjective. CONCLUSIONS: Patients did not report significantly increased anesthetic injection pain level during subsequent stages of Mohs.

Dermatopathologic features of cutaneous squamous cell carcinoma and actinic keratosis: Consensus criteria and proposed reporting guidelines.

BACKGROUND: There is considerable variation in the literature regarding the dermatopathologic diagnostic features of and reporting guidelines for actinic keratosis (AK) and cutaneous squamous cell carcinoma (cSCC). OBJECTIVE: To develop consensus recommendations regarding diagnostic criteria, nomenclature, and reporting of AK and cSCC. METHODS: Literature review and cross-sectional multiround Delphi process including an international group of expert dermatopathologists followed by a consensus meeting. RESULTS: Consensus was achieved regarding the key dermatopathologic features necessary for diagnosing cSCC, AK, and associated variants; grading of degree of cellular differentiation in cSCC; utility of immunohistochemistry for diagnosis of cSCC; and pathologic features that should be reported for cSCC and AK. LIMITATIONS: Consensus was not achieved on all questions considered. CONCLUSION: Despite the lack of clarity in the literature, there is consensus among expert dermatopathologists regarding diagnostic criteria and appropriate reporting of AK and cSCC. Widespread implementation of these consensus recommendations may improve communication between dermatopathologists and clinicians, facilitating appropriate treatment of AK and cSCC.

Cytologic atypia of benign inflammatory versus neoplastic cutaneous squamous lesions.

BACKGROUND: Cytologic atypia encompasses several features of abnormal cellular morphology. We sought to quantify these features in benign and premalignant/malignant squamous cell lesions to better characterize criteria for malignancy. METHODS: We conducted a rater-blinded observational study in which histopathology slides were evaluated under light microscopy, and the presence and relative quantity of 24 distinct cytological features were recorded, along with respective diagnoses. Each slide was evaluated, and the ratings were recorded and analyzed. RESULTS: The most helpful findings, whose presence in high numbers indicates an increased likelihood that the tissue sample is premalignant/malignant, were: (1) pleomorphic parakeratosis; (2) pleomorphic nuclei in the epithelium; (3) irregular nuclei; (4) thick refractile nuclear envelope; (5) presence of nuclear hyperchromasia (dark gray); (6) peripheral nucleoli; and (7) nucleolar stems. Higher values of round or oval nuclear shape and vesicular nuclei increase the likelihood that the tissue sample is benign. CONCLUSIONS: Certain nuclear features have a higher association with premalignancy/malignancy and may guide histologic evaluation of a given lesion. These findings can be used in combination with architectural features and clinical history to add to a complete diagnostic picture.

Dermatofibroma Versus Dermatofibrosarcoma Protuberans: A Nuclear Morphology Study.

ABSTRACT: The locally invasive soft-tissue sarcoma, dermatofibrosarcoma protuberans (DFSPs), shares certain histologic features of the much more common and benign dermatofibroma (DF). While immunohistochemical stains, specifically cluster of differentiation 34 and Factor XIIIa, can be used to distinguish the 2 entities using microscopy, these markers are not entirely sensitive nor specific. Three-dimensionally, DFSP nuclei resemble a "puck" or "coin"-like shape. As hematoxylin/eosin-stained slides are prepared, these "puck" nuclei are fixed in an infinite number of orientations depending on their current position in rotation about their axes within the tumor cells. Under histological examination, this random nuclear positioning produces the appearance of 2 predominate morphologies: an ovoid "disk" shape (en face) and a narrow spindled shape (side view), which distribute in a roughly 50:50 ratio throughout the tumor sample slide. Nuclear morphology was analyzed in 324 DFSP and DF samples at high magnification (×400) to determine the presence or absence of a predominant morphology in which nuclei appear to alternate between an ovoid (en face) and spindled (side view) throughout most of the tumor sample. An alternating ovoid-spindled nuclear morphology was the predominant cytology in 98% of DFSP and was not predominant in 100% of DF samples (P < 0.001). This morphology was found to be highly specific (Sp = 1) and sensitive (Sn = 0.98) for DFSP. This unique nuclear morphology may be a more sensitive and specific diagnostic tool in identifying DFSP from DF in comparison with costly immunohistochemical stains.

Treatment of Surgical Scars With Combination Pulsed Dye and Fractional Nonablative Laser: A Randomized Controlled Trial.

OBJECTIVE: To assess the effectiveness and safety of combined pulsed-dye laser (PDL) and NAFL for treatment of surgical scars. SUMMARY BACKGROUND DATA: PDL and NAFL have not been compared to healing by time alone. METHODS: Randomized controlled, single-blinded clinical trial at an urban, university hospital. Healthy adults' status post skin surgery with primary closure were randomized to either 3 sessions of combination PDL and NAFL every 2 to 8 weeks, or control of no treatment. At baseline and 36-week follow-up, Patient and observer Scar Assessment Scale and Scar Cosmesis Assessment and Rating were completed by participants and blinded physicians. The primary outcome was scar improvement, as measured by the score difference over time. RESULTS: Of 76 participants, 52 completed the study (July 2017 to June 2019). No severe adverse events were reported. Patient and observer Scar Assessment Scale assessments demonstrated improvement in total score in the laser group compared to controls, as reported by patients [mean difference (standard deviation), laser: 12.86 (6.91) vs control: 7.25 (6.34); P = 0.004] and blinded physicians [18.32 (8.69) vs 13.08 (9.63); P = 0.044]. Patients observed a greater improvement in scar thickness [3.68 (2.04) vs 1.88 (1.85); P = 0.002] and stiffness [3.57 (2.78) vs 1.50 (2.11); P = 0.004] with lasers, and physicians reported greater improvement in vascularity [3.71 (1.98) vs 1.71 (1.52); P = 0.0002]. The live Scar Cosmesis Assessment and Rating subscore for erythema improved significantly with lasers [1.04 (0.79) vs 0.42 (0.50); P = 0.001]. CONCLUSIONS AND RELEVANCE: Combined PDL and NAFL resulted in scar improvement. Scar thickness, stiffness, and erythema were improved. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03057964).

Development of a core outcome set for basal cell carcinoma.

BACKGROUND: There is variation in the outcomes reported in clinical studies of basal cell carcinoma. This can prevent effective meta-analyses from answering important clinical questions. OBJECTIVE: To identify a recommended minimum set of core outcomes for basal cell carcinoma clinical trials. METHODS: Patient and professional Delphi process to cull a long list, culminating in a consensus meeting. To be provisionally accepted, outcomes needed to be deemed important (score, 7-9, with 9 being the maximum) by 70% of each stakeholder group. RESULTS: Two hundred thirty-five candidate outcomes identified via a systematic literature review and survey of key stakeholders were reduced to 74 that were rated by 100 health care professionals and patients in 2 Delphi rounds. Twenty-seven outcomes were provisionally accepted. The final core set of 5 agreed-upon outcomes after the consensus meeting included complete response; persistent or serious adverse events; recurrence-free survival; quality of life; and patient satisfaction, including cosmetic outcome. LIMITATIONS: English-speaking patients and professionals rated outcomes extracted from English language studies. CONCLUSION: A core outcome set for basal cell carcinoma has been developed. The use of relevant measures may improve the utility of clinical research and the quality of therapeutic guidance available to clinicians.

Utility of high-resolution ultrasound in measuring subcutaneous fat thickness.

OBJECTIVE: Previous studies conclude that high-resolution ultrasound (HRUS) enables noninvasive and accurate measurements of subcutaneous fat thickness. The primary objective of this cross-sectional study was to better characterize subcutaneous fat thickness measurements in a diverse patient population using HRUS. Secondarily, we sought to correlate these measurements with patients' body image. METHODS: A cross-sectional study to measure subcutaneous fat measurements at seven distinct anatomic sites, including upper and lower extremities, submental, and torso regions, in 40 men and women of different ages and races using HRUS. Independent t-tests and analysis of variance were performed to analyze findings. RESULTS: In our patient population, on average, women had thicker subcutaneous fat than men at all anatomic sites. Asian patients had significantly reduced fat thickness at peripheral anatomic sites, such as arms when compared to patients who identified as Black and Other (p = 0.05 and p = 0.008, respectively). Lastly, women reported decreased total body satisfaction at all anatomic sites when compared to men. CONCLUSION: The information obtained and methods developed in this study may be utilized clinically during patient selection for fat reduction procedures, including for estimating the degree of likely benefit; for managing pathologies involving subcutaneous fat thickness alteration; and to monitor the progression of lipodystrophy secondary to disease or drugs.

Dermatology Match Preference Signaling Tokens: Impact and Implications.

BACKGROUND: The dermatology residency application process implemented a new system of preference signaling tokens (PSTs) in the 2021-2022 cycle to allow applicants to express a higher level of interest in specific programs. Limited data are available on the utilization and impact of these tokens. OBJECTIVE: To determine the impact of PSTs on the application process and where in the process PSTs had the greatest influence. MATERIALS AND METHODS: A 14-question survey was sent to 62 ACGME-accredited dermatology residency programs. Primary outcomes were PST impact on 2021-2022 applications. Variables were evaluated using open-ended questions, yes/no responses, and importance ratings from 0 to 100. RESULTS: An average of 7.1% of applicants were offered interviews, but 21.1% of applicants that submitted PSTs were interviewed versus 3.7% of nonsubmitters. 22.5% of ranked applicants and 19% of matched applicants submitted a PST to that program. LIMITATIONS: Not all programs responded, and PST submission restrictions could not be assessed. CONCLUSION: The greatest PST impact was on the interview decision but had minimal subsequent impact. Given PSTs cannot be submitted to home programs or in-person away rotations, the actual impact was probably greater than found. Programs will continue to implement PSTs in future cycles.

Risk Factors Associated With Long-term Feeding Problems in Preterm Infants: A Scoping Review.

BACKGROUND: Infants who are born preterm are at a high risk of encountering feeding problems. PURPOSE: The aim of this scoping review is to identify risk factors associated with feeding problems that persist beyond infancy in children (aged 1-6 years) who were born preterm (<37 weeks' gestation). METHODS: To perform this scoping review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework was applied. To be included in this study, articles had to be published in peer-reviewed journals, had an empirical study design, examined feeding problems relating to the child's feeding ability or refusal to eat certain texture of foods, and assessed risk factors (age, weight, and medical conditions) associated with long-term feeding problems in children who were born preterm. RESULTS: After abstract and full-text screening, a total of 9 articles meeting the inclusion criteria were included in this study. Findings from this study identified that gestational age and birth weight are significant risk factors and that sex, duration of mechanical ventilation, and length of tube feedings are potential risk factors. IMPLICATIONS FOR PRACTICE: This study confirms that younger and smaller infants are at a high risk of encountering oral feeding difficulties and early interventions services should be focused on these preterm infants. IMPLICATIONS FOR RESEARCH: Evaluation of timing and intensity (dose) of early interventions strategies should be investigated to provide more targeted and effective interventions for younger and smaller preterm infants.

Individual Microcystis colonies harbour distinct bacterial communities that differ by Microcystis oligotype and with time.

Interactions between bacteria and phytoplankton in the phycosphere have impacts at the scale of whole ecosystems, including the development of harmful algal blooms. The cyanobacterium Microcystis causes toxic blooms that threaten freshwater ecosystems and human health globally. Microcystis grows in colonies that harbour dense assemblages of other bacteria, yet the taxonomic composition of these phycosphere communities and the nature of their interactions with Microcystis are not well characterized. To identify the taxa and compositional variance within Microcystis phycosphere communities, we performed 16S rRNA V4 region amplicon sequencing on individual Microcystis colonies collected biweekly via high-throughput droplet encapsulation during a western Lake Erie cyanobacterial bloom. The Microcystis phycosphere communities were distinct from microbial communities in whole water and bulk phytoplankton seston in western Lake Erie but lacked 'core' taxa found across all colonies. However, dissimilarity in phycosphere community composition correlated with sampling date and the Microcystis 16S rRNA oligotype. Several taxa in the phycosphere were specific to and conserved with Microcystis of a single oligotype or sampling date. Together, this suggests that physiological differences between Microcystis strains, temporal changes in strain phenotypes, and the composition of seeding communities may impact community composition of the Microcystis phycosphere.

The genetic and ecophysiological diversity of Microcystis.

Microcystis is a cyanobacterium that forms toxic blooms in freshwater ecosystems around the world. Biological variation among taxa within the genus is apparent through genetic and phenotypic differences between strains and via the spatial and temporal distribution of strains in the environment, and this fine-scale diversity exerts strong influence over bloom toxicity. Yet we do not know how varying traits of Microcystis strains govern their environmental distribution, the tradeoffs and links between these traits, or how they are encoded at the genomic level. Here we synthesize current knowledge on the importance of diversity within Microcystis and on the genes and traits that likely underpin ecological differentiation of taxa. We briefly review spatial and environmental patterns of Microcystis diversity in the field and genetic evidence for cohesive groups within Microcystis. We then compile data on strain-level diversity regarding growth responses to environmental conditions and explore evidence for variation of community interactions across Microcystis strains. Potential links and tradeoffs between traits are identified and discussed. The resulting picture, while incomplete, highlights key knowledge gaps that need to be filled to enable new models for predicting strain-level dynamics, which influence the development, toxicity and cosmopolitan nature of Microcystis blooms.

An evaluation of a veterinary-specific mental health service.

BACKGROUND: Veterinary professionals are at increased risk of suicide and mental health difficulties compared to the general population. Vetlife Health Support (VHS) is a mental health case management service for veterinarians with mental health difficulties. AIMS: To evaluate the VHS case management service from the service user's perspective. METHODS: Service users (n = 98) completed questionnaires assessing their experience with VHS and current mental health status using the Kessler-6 Scale. A sub-sample was interviewed and the data qualitatively analysed (n = 14). RESULTS: The results show that 97% (n = 95) reported a positive experience with VHS and 98% (n = 96) reported VHS staff respected and listened to them. Participants reported significant improvements in relationships with others after VHS (P < 0.001) and were significantly more likely to be in receipt of formal mental health care after VHS than before (P < 0.01). The main emergent themes from the qualitative interviews were (i) positive communication between clinician and service users, (ii) veterinary-specific mental health services were regarded as important to understanding service users' circumstances, (iii) knowing someone is supporting them positively impacted wellbeing and (iv) confusion with discharge status. CONCLUSIONS: Most participants reported positive experiences with VHS. Quantitatively, data showed that participants reported significant improvements in relationships and access to formal mental health care after contact with VHS. Interviews with service users revealed that they felt speaking to a mental health professional with veterinary-specific knowledge was beneficial for their wellbeing. Further evaluation assessing whether VHS leads to a measurable impact on psychological wellbeing is recommended.