The lethal and sublethal impacts of two tire rubber-derived chemicals on brook trout (Salvelinus fontinalis) fry and fingerlings.

Recent toxicity studies of stormwater runoff implicated N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-quinone) as the contaminant responsible for the mass mortality of coho salmon (Oncorhynchus kisutch). In the wake of this discovery, 6PPD-quinone has been measured in waterways around urban centers, along with other tire wear leachates like hexamethoxymethylmelamine (HMMM). The limited data available for 6PPD-quinone have shown toxicity can vary depending on the species. In this study we compared the acute toxicity of 6PPD-quinone and HMMM to Brook trout (Salvelinus fontinalis) fry and fingerlings. Our results show that fry are ∼3 times more sensitive to 6PPD-quinone than fingerlings. Exposure to HMMM ≤6.6 mg/L had no impact on fry survival. These results highlight the importance of conducting toxicity tests on multiple life stages of fish species, and that relying on fingerling life stages for species-based risk assessment may underestimate the impacts of exposure. 6PPD-quinone also had many sublethal effects on Brook trout fingerlings, such as increased interlamellar cell mass (ILCM) size, hematocrit, blood glucose, total CO2, and decreased blood sodium and chloride concentrations. Linear relationships between ILCM size and select blood parameters support the conclusion that 6PPD-quinone toxicity is an outcome of osmorespiratory challenges imposed by gill impairment.

Correction to "Investigation of 6PPD-Quinone in Rubberized Asphalt Concrete Mixtures".

[This corrects the article DOI: 10.1021/acsenvironau.3c00023.].

Reactive Oxygen Species and Chromophoric Dissolved Organic Matter Drive the Aquatic Photochemical Pathways and Photoproducts of 6PPD-quinone under Simulated High-Latitude Conditions.

The photochemical degradation pathways of 6PPD-quinone (6PPDQ, 6PPD-Q), a toxic transformation product of the tire antiozonant 6PPD, were determined under simulated sunlight conditions typical of high-latitude surface waters. Direct photochemical degradation resulted in 6PPDQ half-lives ranging from 17.5 h at 20 °C to no observable degradation over 48 h at 4 °C. Sensitization of excited triplet-state pathways using Cs+ and Ar purging demonstrated that 6PPDQ does not decompose significantly from a triplet state relative to a singlet state. However, assessment of processes involving reactive oxygen species (ROS) quenchers and sensitizers indicated that singlet oxygen and hydroxyl radical do significantly contribute to the degradation of 6PPDQ. Investigation of these processes in natural lake waters indicated no difference in attenuation rates for direct photochemical processes at 20 °C. This suggests that direct photochemical degradation will dominate in warm waters, while indirect photochemical pathways will dominate in cold waters, involving ROS mediated by chromophoric dissolved organic matter (CDOM). Overall, the aquatic photodegradation rate of 6PPDQ will be strongly influenced by the compounding effects of environmental factors such as light screening and temperature on both direct and indirect photochemical processes. Transformation products were identified via UHPLC-Orbitrap mass spectrometry, revealing four major processes: (1) oxidation and cleavage of the quinone ring in the presence of ROS, (2) dealkylation, (3) rearrangement, and (4) deamination. These data indicate that 6PPDQ can photodegrade in cool, sunlit waters under the appropriate conditions: t1/2 = 17.4 h tono observable decrease (direct); t1/2 = 5.2-11.2 h (indirect, CDOM).

TENT2, TUT4, and TUT7 selectively regulate miRNA sequence and abundance.

TENTs generate miRNA isoforms by 3' tailing. However, little is known about how tailing regulates miRNA function. Here, we generate isogenic HEK293T cell lines in which TENT2, TUT4 and TUT7 are knocked out individually or in combination. Together with rescue experiments, we characterize TENT-specific effects by deep sequencing, Northern blot and in vitro assays. We find that 3' tailing is not random but highly specific. In addition to its known adenylation, TENT2 contributes to guanylation and uridylation on mature miRNAs. TUT4 uridylates most miRNAs whereas TUT7 is dispensable. Removing adenylation has a marginal impact on miRNA levels. By contrast, abolishing uridylation leads to dysregulation of a set of miRNAs. Besides let-7, miR-181b and miR-222 are negatively regulated by TUT4/7 via distinct mechanisms while the miR-888 cluster is upregulated specifically by TUT7. Our results uncover the selective actions of TENTs in generating 3' isomiRs and pave the way to investigate their functions.

Concentrations of Tire Additive Chemicals and Tire Road Wear Particles in an Australian Urban Tributary.

Tire road wear particles (TRWPs) are one of the largest sources of microplastics to the urban environment with recent concerns as they also provide a pathway for additive chemicals to leach into the environment. Stormwater is a major source of TRWPs and associated additives to urban surface water, with additives including the antioxidant derivative N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-quinone) demonstrating links to aquatic toxicity at environmentally relevant concentrations. The present study used complementary analysis methods to quantify both TRWPs and a suite of known tire additive chemicals (including 6PPD-quinone) to an urban tributary in Australia during severe storm events. Concentrations of additives increased more than 40 times during storms, with a maximum concentration of 2760 ng/L for ∑15additives, 88 ng/L for 6PPD-quinone, and a similar profile observed in each storm. TRWPs were detected during storm peaks with a maximum concentration between 6.4 and 18 mg/L, and concentrations of TRWPs and all additives were highly correlated. Contaminant mass loads to this catchment were estimated as up to 100 g/storm for ∑15additives, 3 g/storm for 6PPD-quinone, and between 252 and 730 kg of TRWPs/storm. While 6PPD-quinone concentrations in this catchment were lower than previous studies, elevated concentrations post storm suggest prolonged aquatic exposure.

A Direct Mass Spectrometry Method for the Rapid Analysis of Ubiquitous Tire-Derived Toxin N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine Quinone (6-PPDQ).

The oxidative transformation product of a common tire preservative, identified as N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6-PPDQ), has recently been found to contribute to "urban runoff mortality syndrome" in Coho salmon at nanogram per liter levels. Given the number of fish-bearing streams with multiple stormwater inputs, large-scale campaigns to identify 6-PPDQ sources and evaluate mitigation strategies will require sensitive, high-throughput analytical methods. We report the development and optimization of a direct sampling tandem mass spectrometry method for semiquantitative 6-PPDQ determinations using a thin polydimethylsiloxane membrane immersion probe. The method requires no sample cleanup steps or chromatographic separations, even in complex, heterogeneous samples. Quantitation is achieved by the method of standard additions, with a detection limit of 8 ng/L and a duty cycle of 15 min/sample. High-throughput screening provides semiquantitative concentrations with similar sensitivity and a full analytical duty cycle of 2.5 min/sample. Preliminary data and performance metrics are reported for 6-PPDQ present in representative environmental and stormwater samples. The method is readily adapted for real-time process monitoring, demonstrated by following the dissolution of 6-PPDQ from tire fragments and subsequent removal in response to added sorbents.

Variable levels of drift in tunicate cardiopharyngeal gene regulatory elements.

BACKGROUND: Mutations in gene regulatory networks often lead to genetic divergence without impacting gene expression or developmental patterning. The rules governing this process of developmental systems drift, including the variable impact of selective constraints on different nodes in a gene regulatory network, remain poorly delineated. RESULTS: Here we examine developmental systems drift within the cardiopharyngeal gene regulatory networks of two tunicate species, Corella inflata and Ciona robusta. Cross-species analysis of regulatory elements suggests that trans-regulatory architecture is largely conserved between these highly divergent species. In contrast, cis-regulatory elements within this network exhibit distinct levels of conservation. In particular, while most of the regulatory elements we analyzed showed extensive rearrangements of functional binding sites, the enhancer for the cardiopharyngeal transcription factor FoxF is remarkably well-conserved. Even minor alterations in spacing between binding sites lead to loss of FoxF enhancer function, suggesting that bound trans-factors form position-dependent complexes. CONCLUSIONS: Our findings reveal heterogeneous levels of divergence across cardiopharyngeal cis-regulatory elements. These distinct levels of divergence presumably reflect constraints that are not clearly associated with gene function or position within the regulatory network. Thus, levels of cis-regulatory divergence or drift appear to be governed by distinct structural constraints that will be difficult to predict based on network architecture.

Reversal of Tetracycline Resistance in Escherichia coli by Noncytotoxic bis(Tryptophan)s.

Nine bis(tryptophan) derivatives (BTs) and two control compounds were synthesized and tested for antimicrobial activity against two Escherichia coli strains and a Staphylococcus aureus strain. The effects of linker type, shape, and conformational rigidity were manifested in dramatic differences in altering tetracycline potency when coadministered with that antibiotic. A reversal of resistance was observed for an E. coli strain having a TetA efflux pump. Survival of mammalian cells was assayed with good result.

A large multicenter outcome study of female genital plastic surgery.

INTRODUCTION: Female Genital Plastic Surgery, a relatively new entry in the field of Cosmetic and Plastic Surgery, has promised sexual enhancement and functional and cosmetic improvement for women. Are the vulvovaginal aesthetic procedures of Labiaplasty, Vaginoplasty/Perineoplasty ("Vaginal Rejuvenation") and Clitoral Hood Reduction effective, and do they deliver on that promise? For what reason do women seek these procedures? What complications are evident, and what effects are noted regarding sexual function for women and their partners? Who should be performing these procedures, what training should they have, and what are the ethical considerations? AIM: This study was designed to produce objective, utilizable outcome data regarding FGPS. MAIN OUTCOME MEASURES: 1) Reasons for considering surgery from both patient's and physician's perspective; 2) Pre-operative sexual functioning per procedure; 3) Overall patient satisfaction per procedure; 4) Effect of procedure on patient's sexual enjoyment, per procedure; 5) Patient's perception of effect on her partner's sexual enjoyment, per procedure; 6) Complications. METHODS: This cross-sectional study, including 258 women and encompassing 341 separate procedures, comes from a group of twelve gynecologists, gynecologic urologists and plastic surgeons from ten centers in eight states nationwide. 104 labiaplasties, 24 clitoral hood reductions, 49 combined labiaplasty/clitoral hood reductions, 47 vaginoplasties and/or perineoplasties, and 34 combined labiaplasty and/or reduction of the clitoral hood plus vaginoplasty/perineoplasty procedures were studied retrospectively, analyzing both patient's and physician's perception of surgical rationale, pre-operative sexual function and several outcome criteria. RESULTS: Combining the three groups, 91.6% of patients were satisfied with the results of their surgery after a 6-42 month follow-up. Significant subjective enhancement in sexual functioning for both women and their sexual partners was noted (p = 0.0078), especially in patients undergoing vaginal tightening/perineal support procedures. Complications were acceptable and not of major consequence. CONCLUSIONS: While emphasizing that these female genital plastic procedures are not performed to correct "abnormalities," as there is a wide range of normality in the external and internal female genitalia, both parous and nulliparous, many women chose to modify their vulvas and vaginas. From the results of this large study pooling data from a diverse group of experienced genital plastic surgeons, outcome in both general and sexual satisfaction appear excellent.

Atypical presentation of metastatic basal cell carcinoma.

Basal cell carcinoma is an indolent, slow-growing tumor that rarely metastasizes. Approximately 70% of tumors occur in the head and neck regions. If a basal cell tumor metastasizes, it usually spreads to the regional lymph nodes first, followed by the lungs. We describe a patient with basal cell carcinoma of the right lower extremity with skin metastases. Skin biopsy of one tumor revealed fibroepithelioma of Pinkus, a rare variant of basal cell carcinoma.

Noninvasive skin measurements after CO(2) and erbium laser resurfacing.

BACKGROUND: Improvement in skin after laser resurfacing depends on treatment to a precise level. The target treatment level will depend on skin type, anatomic location, and severity of the presenting problem. The development of noninvasive skin measurements that correlate with histologic changes would provide a useful intraoperative guide for treatment. OBJECTIVE: The relationship among different types of lasers and levels of applied energy; objective real-time noninvasive measures of the skin; and histologic condition were studied in an attempt to gain information that could aid in achieving safer and more predictable laser skin resurfacing. METHODS: The paraspinal skin of Yorkshire hybrid pigs was used for the study. In pig 1, study sites were treated with the Ultrapulse CO(2) laser (Coherent, Inc, Santa Clara, CA) with the CP-G at 300 ml for 0 to 5 passes. The Sciton Contour erbium: YAG llaser (Contour, Sciton, Palo Alto, CA) set at 200 mum of pure ablation was used to treat a separate but adjacent area for 0 to 5 passes. Treated sites and control sites were evaluated by measurements of biomechanical properties, digital imaging, and barrier integrity. In pig 2, the study was repeated with the Sciton Contour erbium:YAG laser at 10 different energy levels. Full-thickness punch biopsy specimens were obtained immediately after treatment and correlated with the biomechanical measures. RESULTS: After the third pass with the CO(2) laser, there was no additional tissue ablation or change in surface biophysical measurements. There was an apparent increase in inflammation in the lower dermis with passes 4 and 5 seen on day 2 biopsies that suggested deeper thermal effects. The erbium laser continued to ablate with increasing applied energy. The change in viscoelastic creep correlated with the laser energy applied and inversely correlated with the remaining dermal depth of the skin after laser treatment. CONCLUSIONS: The measurement of immediate changes in viscoelastic creep should be further studied as a means of guiding intraoperative erbium laser resurfacing. Histologic evaluation suggests that the erbium:YAG laser may be a more effective tool for dermal ablation than the CO(2) laser.

Skin resurfacing for the burned patient.

It has been estimated that 2 million people per year have burns requiring medical attention in the United States. The available and expert clinicians in dedicated burn centers around the country have cared successfully for these patients and given them a second chance at a functional life. It still behooves current-day plastic surgeons to be knowledgeable and adept in their care, not only because they may be called upon at times to manage some of the smaller acute burns, but also because many of the general principles of burn reconstruction and wound management are relevant to other areas of general plastic surgery. Acute burns should be dealt with like any other major trauma with the ABCs of aggressive resuscitation and airway management. Like any other wound, debridement and nutrition are important (i.e., early escharectomy of the burn wound and enteral nutrition during the hypermetabolic state). Early coverage of the open wound is essential to limit bacterial colonization and prevent infection and to reduce fluid and electrolyte and heat loss. If autografts are not available immediately, temporary coverage with one of the above-mentioned barrier materials should be used. Still, autografts, when available, should be the burn surgeon's first choice. Donor sites may be reharvested to provide more autograft than was anticipated with large-percentage TBSA burns. Physicians should keep in mind the advantages (and disadvantages) of using the scalp and back. As far as research and technological advances in the area of plastic surgery, burn surgery may be the most progressive, with the evolution of biologic tissue-engineered skin substitutes and the research of growth factors in healing. Further improvements in tissue engineering and technology should result in even more effective skin substitutes and hence better functional and aesthetic outcomes with economic efficiency in large burns.