Removal of phosphoglycolate in hyperthermophilic archaea.

Many organisms that utilize the Calvin-Benson-Bassham (CBB) cycle for autotrophic growth harbor metabolic pathways to remove and/or salvage 2-phosphoglycolate, the product of the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). It has been presumed that the occurrence of 2-phosphoglycolate salvage is linked to the CBB cycle, and in particular, the C2 pathway to the CBB cycle and oxygenic photosynthesis. Here, we examined 2-phosphoglycolate salvage in the hyperthermophilic archaeon Thermococcus kodakarensis, an obligate anaerobe that harbors a Rubisco that functions in the pentose bisphosphate pathway. T. kodakarensis harbors enzymes that have the potential to convert 2-phosphoglycolate to glycine and serine, and their genes were identified by biochemical and/or genetic analyses. 2-phosphoglycolate phosphatase activity increased 1.6-fold when cells were grown under microaerobic conditions compared to anaerobic conditions. Among two candidates, TK1734 encoded a phosphatase specific for 2-phosphoglycolate, and the enzyme was responsible for 80% of the 2-phosphoglycolate phosphatase activity in T. kodakarensis cells. The TK1734 disruption strain displayed growth impairment under microaerobic conditions, which was relieved upon addition of sodium sulfide. In addition, glycolate was detected in the medium when T. kodakarensis was grown under microaerobic conditions. The results suggest that T. kodakarensis removes 2-phosphoglycolate via a phosphatase reaction followed by secretion of glycolate to the medium. As the Rubisco in T. kodakarensis functions in the pentose bisphosphate pathway and not in the CBB cycle, mechanisms to remove 2-phosphoglycolate in this archaeon emerged independent of the CBB cycle.

Formate-tetrahydrofolate ligase: supplying the cytosolic one-carbon network in roots with one-carbon units originating from glycolate.

The metabolism of tetrahydrofolate (H4PteGlun)-bound one-carbon (C1) units (C1 metabolism) is multifaceted and required for plant growth, but it is unclear what of many possible synthesis pathways provide C1 units in specific organelles and tissues. One possible source of C1 units is via formate-tetrahydrofolate ligase, which catalyzes the reversible ATP-driven production of 10-formyltetrahydrofolate (10-formyl-H4PteGlun) from formate and tetrahydrofolate (H4PteGlun). Here, we report biochemical and functional characterization of the enzyme from Arabidopsis thaliana (AtFTHFL). We show that the recombinant AtFTHFL has lower Km and kcat values with pentaglutamyl tetrahydrofolate (H4PteGlu5) as compared to monoglutamyl tetrahydrofolate (H4PteGlu1), resulting in virtually identical catalytic efficiencies for the two substrates. Stable transformation of Arabidopsis plants with the EGFP-tagged AtFTHFL, followed with fluorescence microscopy, demonstrated cytosolic signal. Two independent T-DNA insertion lines with impaired AtFTHFL function had shorter roots compared to the wild type plants, demonstrating the importance of this enzyme for root growth. Overexpressing AtFTHFL led to the accumulation of H4PteGlun + 5,10-methylene-H4PteGlun and serine, accompanied with the depletion of formate and glycolate, in roots of the transgenic Arabidopsis plants. This metabolic adjustment supports the hypothesis that AtFTHFL feeds the cytosolic C1 network in roots with C1 units originating from glycolate, and that these units are then used mainly for biosynthesis of serine, and not as much for the biosynthesis of 5-methyl-H4PteGlun, methionine, and S-adenosylmethionine. This finding has implications for any future attempts to engineer one-carbon unit-requiring products through manipulation of the one-carbon metabolic network in non-photosynthetic organs.

Marine Proteobacteria metabolize glycolate via the ß-hydroxyaspartate cycle.

One of the most abundant sources of organic carbon in the ocean is glycolate, the secretion of which by marine phytoplankton results in an estimated annual flux of one petagram of glycolate in marine environments1. Although it is generally accepted that glycolate is oxidized to glyoxylate by marine bacteria2-4, the further fate of this C2 metabolite is not well understood. Here we show that ubiquitous marine Proteobacteria are able to assimilate glyoxylate via the ß-hydroxyaspartate cycle (BHAC) that was originally proposed 56 years ago5. We elucidate the biochemistry of the BHAC and describe the structure of its key enzymes, including a previously unknown primary imine reductase. Overall, the BHAC enables the direct production of oxaloacetate from glyoxylate through only four enzymatic steps, representing-to our knowledge-the most efficient glyoxylate assimilation route described to date. Analysis of marine metagenomes shows that the BHAC is globally distributed and on average 20-fold more abundant than the glycerate pathway, the only other known pathway for net glyoxylate assimilation. In a field study of a phytoplankton bloom, we show that glycolate is present in high nanomolar concentrations and taken up by prokaryotes at rates that allow a full turnover of the glycolate pool within one week. During the bloom, genes that encode BHAC key enzymes are present in up to 1.5% of the bacterial community and actively transcribed, supporting the role of the BHAC in glycolate assimilation and suggesting a previously undescribed trophic interaction between autotrophic phytoplankton and heterotrophic bacterioplankton.

The catabolism of ethylene glycol by Rhodococcus jostii RHA1 and its dependence on mycofactocin.

Ethylene glycol (EG) is a widely used industrial chemical with manifold applications and also generated in the degradation of plastics such as polyethylene terephthalate. Rhodococcus jostii RHA1 (RHA1), a potential biocatalytic chassis, grows on EG. Transcriptomic analyses revealed four clusters of genes potentially involved in EG catabolism: the mad locus, predicted to encode mycofactocin-dependent alcohol degradation, including the catabolism of EG to glycolate; two GCL clusters, predicted to encode glycolate and glyoxylate catabolism; and the mft genes, predicted to specify mycofactocin biosynthesis. Bioinformatic analyses further revealed that the mad and mft genes are widely distributed in mycolic acid-producing bacteria such as RHA1. Neither ΔmadA nor ΔmftC RHA1 mutant strains grew on EG but grew on acetate. In resting cell assays, the ΔmadA mutant depleted glycolaldehyde but not EG from culture media. These results indicate that madA encodes a mycofactocin-dependent alcohol dehydrogenase that initiates EG catabolism. In contrast to some mycobacterial strains, the mad genes did not appear to enable RHA1 to grow on methanol as sole substrate. Finally, a strain of RHA1 adapted to grow ~3× faster on EG contained an overexpressed gene, aldA2, predicted to encode an aldehyde dehydrogenase. When incubated with EG, this strain accumulated lower concentrations of glycolaldehyde than RHA1. Moreover, ecotopically expressed aldA2 increased RHA1's tolerance for EG further suggesting that glycolaldehyde accumulation limits growth of RHA1 on EG. Overall, this study provides insights into the bacterial catabolism of small alcohols and aldehydes and facilitates the engineering of Rhodococcus for the upgrading of plastic waste streams.IMPORTANCEEthylene glycol (EG), a two-carbon (C2) alcohol, is produced in high volumes for use in a wide variety of applications. There is burgeoning interest in understanding and engineering the bacterial catabolism of EG, in part to establish circular economic routes for its use. This study identifies an EG catabolic pathway in Rhodococcus, a genus of bacteria well suited for biocatalysis. This pathway is responsible for the catabolism of methanol, a C1 feedstock, in related bacteria. Finally, we describe strategies to increase the rate of degradation of EG by increasing the transformation of glycolaldehyde, a toxic metabolic intermediate. This work advances the development of biocatalytic strategies to transform C2 feedstocks.

N-terminal acetylation orchestrates glycolate-mediated ROS homeostasis to promote rice thermoresponsive growth.

Climate warming poses a significant threat to global crop production and food security. However, our understanding of the molecular mechanisms governing thermoresponsive development in crops remains limited. Here we report that the auxiliary subunit of N-terminal acetyltransferase A (NatA) in rice OsNAA15 is a prerequisite for rice thermoresponsive growth. OsNAA15 produces two isoforms OsNAA15.1 and OsNAA15.2, via temperature-dependent alternative splicing. Among the two, OsNAA15.1 is more likely to form a stable and functional NatA complex with the potential catalytic subunit OsNAA10, leading to a thermoresponsive N-terminal acetylome. Intriguingly, while OsNAA15.1 promotes plant growth under elevated temperatures, OsNAA15.2 exhibits an inhibitory effect. We identified two glycolate oxidases (GLO1/5) as major substrates from the thermoresponsive acetylome. These enzymes are involved in hydrogen peroxide (H2O2) biosynthesis via glycolate oxidation. N-terminally acetylated GLO1/5 undergo their degradation through the ubiquitin-proteasome system. This leads to reduced reactive oxygen species (ROS) production, thereby promoting plant growth, particularly under high ambient temperatures. Conclusively, our findings highlight the pivotal role of N-terminal acetylation in orchestrating the glycolate-mediated ROS homeostasis to facilitate thermoresponsive growth in rice.

Exploring yeast biodiversity and process conditions for optimizing ethylene glycol conversion into glycolic acid.

Plastics have become an indispensable material in many fields of human activities, with production increasing every year; however, most of the plastic waste is still incinerated or landfilled, and only 10% of the new plastic is recycled even once. Among all plastics, polyethylene terephthalate (PET) is the most produced polyester worldwide; ethylene glycol (EG) is one of the two monomers released by the biorecycling of PET. While most research focuses on bacterial EG metabolism, this work reports the ability of Saccharomyces cerevisiae and nine other common laboratory yeast species not only to consume EG, but also to produce glycolic acid (GA) as the main by-product. A two-step bioconversion of EG to GA by S. cerevisiae was optimized by a design of experiment approach, obtaining 4.51 ± 0.12 g l-1 of GA with a conversion of 94.25 ± 1.74% from 6.21 ± 0.04 g l-1 EG. To improve the titer, screening of yeast biodiversity identified Scheffersomyces stipitis as the best GA producer, obtaining 23.79 ± 1.19 g l-1 of GA (yield 76.68%) in bioreactor fermentation, with a single-step bioprocess. Our findings contribute in laying the ground for EG upcycling strategies with yeasts.

Delayed Graft Function After Kidney Transplantation: The Role of Residual Diuresis and Waste Products, as Oxalic Acid and Its Precursors.

Delayed graft function (DGF) after kidney transplantation heralds a worse prognosis. In patients with hyperoxaluria, the incidence of DGF is high. Oxalic acid is a waste product that accumulates when kidney function decreases. We hypothesize that residual diuresis and accumulated waste products influence the DGF incidence. Patients transplanted between 2018-2022 participated in the prospective cohort study. Pre-transplant concentrations of oxalic acid and its precursors were determined. Data on residual diuresis and other recipient, donor or transplant related variables were collected. 496 patients were included, 154 were not on dialysis. Oxalic acid, and glyoxylic acid, were above upper normal concentrations in 98.8%, and 100% of patients. Residual diuresis was ≤150 mL/min in 24% of patients. DGF occurred in 157 patients. Multivariable binary logistic regression analysis demonstrated a significant influence of dialysis type, recipient BMI, donor type, age, and serum creatinine on the DGF risk. Residual diuresis and glycolic acid concentration were inversely proportionally related to this risk, glyoxylic acid directly proportionally. Results in the dialysis population showed the same results, but glyoxylic acid lacked significance. In conclusion, low residual diuresis is associated with increased DGF incidence. Possibly accumulated waste products also play a role. Pre-emptive transplantation may decrease the incidence of DGF.

Nephrocalcinosis can disappear in infants receiving early lumasiran therapy.

BACKGROUND: Lumasiran is the first RNA interference (RNAi) therapy of primary hyperoxaluria type 1 (PH1). Here, we report on the rapid improvement and even disappearance of nephrocalcinosis after early lumasiran therapy. CASE-DIAGNOSIS/TREATMENT: In patient 1, PH1 was suspected due to incidental discovery of nephrocalcinosis stage 3 in a 4-month-old boy. Bilateral nephrocalcinosis stage 3 was diagnosed in patient 2 at 22 months concomitantly to acute pyelonephritis. Urinary oxalate (UOx) and glycolate (UGly) were increased in both patients allowing to start lumasiran therapy before genetic confirmation. Nephrocalcinosis started to improve and disappeared after 27 months and 1 year of treatment in patients 1 and 2, respectively. CONCLUSION: These cases illustrate the efficacy of early lumasiran therapy in infants to improve and even normalize nephrocalcinosis. As proposed in the 2023 European guidelines, the interest of starting treatment quickly without waiting for genetic confirmation may have an impact on long-term outcomes.

Selective detection of ionic liquid fluorescence probes for visual colorimetry of different metal ions.

At present, the fast distinction of different metal ions in pure water media is not only a great challenge, but also drives the protection of water quality in environmental water bodies. In this paper, a novel ionic liquid fluorescent probe Glycolic Acid-L-Arginine (GA-L-Arg) was rationally created and designed through an in-depth study of ionic liquids. It is also used as an innovative multi-ion fluorescent probe for colorimetric detection and separate identification of Fe3+ and Co2+ in aqueous solutions of various metal ions. GA-L-Arg has excellent water solubility due to the strong hydrophilicity of Glycolic Acid and L-Arginine. The probe showed high sensitivity, extremely significant selectivity, and great pH stability for Fe3+ and Co2+ in pure water. The GA-L-Arg structure and the mechanism of Fe3+ and Co2+ detection were analyzed by infrared spectroscopic characterization and quantum chemical calculations. More importantly, the distinct colorimetric partitioning of Fe3+ and Co2+ was performed by the unique extraction of Fe3+ in the presence of the fluorescent probe and buffer solution.

A mycofactocin-associated dehydrogenase is essential for ethylene glycol metabolism by Rhodococcus jostii RHA1.

Ethylene glycol is an industrially important diol in many manufacturing processes and a building block of polymers, such as poly(ethylene terephthalate). In this study, we found that a mycolic acid-containing bacterium Rhodococcus jostii RHA1 can grow with ethylene glycol as a sole source of carbon and energy. Deletion of a putative glycolate dehydrogenase gene (RHA1_ro03227) abolished growth with ethylene glycol, indicating that ethylene glycol is assimilated via glycolate in R. jostii RHA1. Transcriptome sequencing and gene deletion analyses revealed that a gene homologous to mycofactocin (MFT)-associated dehydrogenase (RHA1_ro06057), hereafter referred to as EgaA, is essential for ethylene glycol assimilation. Furthermore, egaA deletion also negatively affected the utilization of ethanol, 1-propanol, propylene glycol, and 1-butanol, suggesting that EgaA is involved in the utilization of various alcohols in R. jostii RHA1. Deletion of MFT biosynthetic genes abolished growth with ethylene glycol, indicating that MFT is the physiological electron acceptor of EgaA. Further genetic studies revealed that a putative aldehyde dehydrogenase (RHA1_ro06081) is a major aldehyde dehydrogenase in ethylene glycol metabolism by R. jostii RHA1. KEY POINTS: • Rhodococcus jostii RHA1 can assimilate ethylene glycol via glycolate • A mycofactocin-associated dehydrogenase is involved in the oxidation of ethylene glycol • An aldehyde dehydrogenase gene is important for the ethylene glycol assimilation.

Aspects of glass and hybridization protocols for bonding of fiber posts to root dentine.

This study evaluated bond strength of glass fiber posts to root dentin using push-out (PO) and diametral compression (DC), testing glycolic acid as a conditioner and varying dentin moisture. An additional aim was to test whether DC can be an alternative test to PO for bond strength assessment. Eighty bovine teeth were divided into eight groups (n = 10) defined by the use of either 37% glycolic acid or 37% phosphoric acid (PA) on moist or wet dentin before bonding with either Adapter SingleBond/RelyX ARC or One Step Plus/Duo-Link Bisco. Each tooth provided discs with an internal diameter of 2 mm, external diameter of 5 mm, and height of 2 mm, which underwent PO and DC. Finite element analysis (FEA) was carried out on 3D models. When analyzing PO results through linear regression, the highest values of bond strength were observed using glycolic acid on wet dentin in the cervical and middle thirds of the teeth. Analyzing DC results, the only statistical influence on values was the dental thirds. The scatterplot of the DC results and the PO bond strength values indicated no relationship between the results of the two tests (r = 0.03; p = 0.64). PO test detected more sensitive changes in bond strength values than DC.

Chemical Peels for Melasma: A Systematic Review.

BACKGROUND: Melasma is a common chronic, relapsing pigmentary disorder that causes psychological impact. Chemical peels are a well-known therapeutic modality used for accelerating the treatment of melasma. OBJECTIVE: To review the published evidence on the efficacy and safety of chemical peels in the treatment of melasma. METHODS: A systematic review was done. A meta-analysis could not be done due to the heterogeneity of data. RESULT: The authors conducted a PubMed search and included prospective case series of more than 10 cases and randomized controlled trials (RCTs) that have studied the safety and/or efficacy of chemical peel in melasma. Out of 24 studies, 9 were clinical/comparative trials and 15 were RCTs. The total sample size was 1,075. The duration of the study varied from 8 to 36 weeks. Only 8 studies were split face. All studies used self-assessment, physician global assessment, and Melasma Area and Severity Index (MASI) for quantifying the results. Glycolic acid was found to be the most safe and effective in melasma. CONCLUSION: Chemical peels were found to be safe and effective in the management of melasma.

A 15% Trichloroacetic Acid + 3% Glycolic Acid Chemical Peel Series Improves Appearance of Hand Lentigines: An Evaluator-Blinded, Split-Hand Prospective Trial.

BACKGROUND: Improving the appearance of lentigines on the hands is a key component to hand rejuvenation. Soft tissue fillers revolumize hands, but do not address pigmentary changes. OBJECTIVE: This study investigated the effiacy of a 15% trichloroacetic acid (TCA) + 3% glycolic acid (GA) combination peel in improvement of appearance of hand lentigines. METHODS: A prospective evaluator-blinded, split-hand study was performed using a 15% TCA + 3% GA peel to treat patients with hand lentigines. Subjects received a total of 3 treatments at 4-week intervals on 1 hand, with the other hand serving as an untreated control. Final photographs were taken 12 weeks after the last treatment. Two blinded board-certified dermatologists graded improvement in hand lentigines using a 5-point scale. RESULTS: Eighteen of 20 patients completed the study (90%). The mean age was 64.4 years (SE 1.6, range 51-71). The mean pain scores were 3.8 (SE 0.4) on a 10-point scale (1 = no pain, 10 = extremely painful). Blinded evaluators correctly identified the after-treatment photographs in 16 patients (88%). Physician and patient-graded mean improvement of lentigines was significant for treated versus control hands ( p < .01). No adverse events were noted. CONCLUSION: A series of three 15% TCA + 3% GA peels are effective and safe in the treatment of hand lentigines.

Efficacy and safety of lasers versus topical medications for acanthosis nigricans and pseudo-acanthosis nigricans treatment: a systematic review.

Acanthosis nigricans (AN) is a cutaneous disorder identified by well-defined pigmented plaques mostly detected on skin folds. Timely diagnosis and treatment of AN is essential as it could be an early manifestation of an underlying condition. The treatment of choice for AN has not been determined yet. Our study aimed to compare the efficacy and safety of various lasers with topical medications, including cream and peel. PubMed, Scopus, and Web of Science databases, as well as the Google Scholar search engine, were thoroughly searched until May 1st, 2023. Study selection was restricted to clinical trials published in English language comparing lasers with topical treatments. This study followed the PRISMA guidelines for systematic reviews and meta-analyses. Out of 1748 studies, Six clinical trials met our inclusion criteria, with 133 patients. We examined laser therapies, including fractional CO2 laser, 1550-nm erbium fiber laser, and long-pulsed alexandrite laser, while the topical treatments comprised glycolic acid (GA) peel, retinoic acid peel, trichloroacetic acid (TCA) peel, and tretinoin cream. In two studies, GA peel demonstrated favorable results compared to fractional CO2 laser. Besides, fractional CO2 laser exhibited efficacy, surpassing TCA peel in AN management. Additionally, a fractional 1550-nm erbium fiber laser displayed superiority over tretinoin cream in reducing average roughness. Similarly, a long-pulsed alexandrite laser demonstrated its effectiveness in axillary AN treatment compared to the combination of tretinoin and ammonium lactate. Overall, the findings revealed that laser therapy was associated with superior results. Moreover, topical treatments are safe and efficacious in AN management.

Glycolic acid on push-out bond strength of fiber post and smear removal: an in vitro study.

This study aims to investigate glycolic acid (GA) as a final irrigant on push-out bond strength of fiber post and smear removal. Ninety mandibular premolars were stabilized with a silicone key and photographed, and canal cross-section was calculated by image processing software. Round canal morphology was selected. The specimens were divided into five groups (n = 18); 10%GA, 17%EDTA, NaOCl + 10%GA, NaOCl + 17%EDTA, and the control. Fifteen specimens were used for the push-out. Three specimens were evaluated using a scanning electron microscope after post space preparation. Two-way ANOVA and Chi-square were used for statistics. GA presented higher strength than EDTA (p < 0.05). The NaOCl + GA showed higher strength than the NaOCl + EDTA (p < 0.05). The highest values were observed in cervical and lowest in apical thirds (p < 0.05). The most failure type was between dentin and resin (p < 0.05). GA removed the smear in the post space including the apical third. The NaOCl + GA has superiority to NaOCl + EDTA on push-out strength. Glycolic acid improved the bond strength of fiber post when used as a final post space irrigant. The combination of NaOCl and glycolic acid did not negatively affect the bond strength and was more effective compared to the combination with EDTA. Glycolic acid improved the bond strength of fiber post when used as a final post space irrigant. The combination of NaOCl and glycolic acid did not negatively affect the bond strength and was more effective compared to the combination with EDTA.

Multiple Roles of Glycerate Kinase-From Photorespiration to Gluconeogenesis, C4 Metabolism, and Plant Immunity.

Plant glycerate kinase (GK) was previously considered an exclusively chloroplastic enzyme of the glycolate pathway (photorespiration), and its sole predicted role was to return most of the glycolate-derived carbon (as glycerate) to the Calvin cycle. However, recent discovery of cytosolic GK revealed metabolic links for glycerate to other processes. Although GK was initially proposed as being solely regulated by substrate availability, subsequent discoveries of its redox regulation and the light involvement in the production of chloroplastic and cytosolic GK isoforms have indicated a more refined regulation of the pathways of glycerate conversion. Here, we re-evaluate the importance of GK and emphasize its multifaceted role in plants. Thus, GK can be a major player in several branches of primary metabolism, including the glycolate pathway, gluconeogenesis, glycolysis, and C4 metabolism. In addition, recently, the chloroplastic (but not cytosolic) GK isoform was implicated as part of a light-dependent plant immune response to pathogen attack. The origins of glycerate are also discussed here; it is produced in several cell compartments and undergoes huge fluctuations depending on light/dark conditions. The recent discovery of the vacuolar glycerate transporter adds yet another layer to our understanding of glycerate transport/metabolism and that of other two- and three-carbon metabolites.

Development of a Rapid Detection Method for Ethylene Glycol and Glycolic Acid in Feline Samples: A Response to Increasing Antifreeze Poisoning Incidents in Korea.

Recently, cases of antifreeze poisoning in companion animals, particularly cats, have surged in the Republic of Korea. Ethylene glycol (EG), the toxic primary component of antifreeze, is metabolized into glycolic acid (GA), leading to severe metabolic acidosis, acute kidney injury, and death. Traditional detection methods, although effective, are often time-consuming owing to complex sample preparation. This study involved a novel analytical method utilizing GC-MS for EG and LC-MS/MS for GA detection, which streamlined the detection process by eliminating the need for derivatization. The method was validated for accuracy and reliability, enabling the rapid and precise identification of EG and GA in biological samples. This study also included the successful application of this method in a case where initial exposure to antifreeze was not apparent, which highlighted the effectiveness of this method in diagnosing poisoning even in cases where clinical history is unclear. The development of this rapid diagnostic approach addresses the urgent need for the efficient detection of antifreeze poisoning, improving animal welfare and supporting forensic investigations.

Poly Lactic-co-Glycolic Acid Absorbable Plate Graft for Secondary Rhinoplasty in Asian Patients with Unilateral Cleft Lip Nose Deformity.

INTRODUCTION: In secondary cleft lip and nasal deformity (CLND) correction, structural grafts are commonly used to control the nasal tip and restore the symmetry of the ala. However, the septal cartilage in Asians often weak and small. Biocompatible absorbable materials are alternatives to autologous grafts. This study assessed the surgical outcomes and complications of poly lactic-co-glycolic acid (PLGA) plate grafts in secondary CLND correction. METHODS: This study was retrospectively analyzed for patients who underwent secondary rhinoplasty for unilateral CLND correction between March 2015 and November 2020. Using open rhinoplasty, the PLGA plate was grafted as a columellar strut. Clinical photographs taken at the initial (T0) and follow-up visits (T1: short-term, T2: long-term) were analyzed and anthropometric parameters, such as nostril height and width, dome height, and tip height, were measured. RESULTS: Twenty-four patients were included in this study. The mean T1 and T2 periods were 1.0 ± 0.4 and 15.5 ± 3.1 months, respectively. The nostril height ratio increased from 0.78 ± 0.12 at T0 to 0.88 ± 0.08 at T1 and 0.86 ± 0.09 at T2 (p < 0.001; Relapse ratio -2.6 ± 6.7%). The tip height ratio increased from 0.60 ± 0.07 (T0) to 0.66 ± 0.05 (T2) (Relapse ratio -3.7 ± 3.0%). CONCLUSIONS: The PLGA plate graft provided stable nasal tip projection and alar symmetry without major complications. It can be a good option for patients lacking available septal and concha cartilages or apprehensive of additional scarring.

Evaluation of eye irritation potential of experimental cosmetic formulations containing glycolic acid, salicylic acid and ethanol using the Bovine Corneal Opacity and Permeability Assay.

OBJECTIVE: Prototype cosmetic formulations containing short-chain acids and alcohols intended to be applied in the proximity of the eyes are sometimes evaluated for ocular irritation potential using the validated Bovine Corneal Opacity and Permeability Assay (OECD TG 437). We evaluated the eye irritation potential of nine experimental cosmetic formulations designed and prepared by Avon Global Reserach and Development to differ only in the concentrations of Ethanol, Glycolic Acid and Salicylic Acid. METHODS: We analysed the data generated using the BCOP assay. The opacity and permeability values obtained following the exposure of bovine corneas to experimental cosmetic formulations were combined into a single In Vitro Irritancy Score used to rank eye irritation potential. Histopathological examination of treated corneas was used to provide additional information about the depth and degree of the injury and to support the prediction of eye irritation potential of each experimental cosmetic formulation. RESULTS: The In Vitro Irritancy Scores and histopathological analysis showed that experimental formulations containing only Ethanol, Glycolic Acid, or Salicylic Acid alone had, at most, a mild ocular irritation potential. The experimental formulations containing both Ethanol and Glycolic Acid had a mild ocular irritation potential, while the experimental formulations containing both Ethanol and Salicylic Acid had a moderate ocular irritation potential. Severe ocular irritation potential was induced by an experimental formulation containing a combination of Glycolic Acid and Salicylic Acid and it was further accentuated by the addition of Ethanol to the formulation. Our data indicate a possible synergistic effect on eye irritation potential of Ethanol, Glycolic Acid and Salicylic Acid in at least some experimental cosmetic formulations. Further, our results provide insight on an apparent concentration-dependent ocular irritation potential effect of combinations of Glycolic Acid, Salicylic Acid and Ethanol in at least one experimental cosmetic formulation. CONCLUSIONS: The results presented herein emphasise the need to consider in vitro testing of prototype cosmetic formulations containing combinations of Ethanol, Glycolic Acid and Salicylic Acid rather than relying on any predicted additive effect on ocular irritation based solely on previously generated results of similar formulations containing Ethanol, Glycolic Acid or Salicylic Acid alone. Further work is required to understand the significance of these observations and to elucidate the mechanisms responsible for the apparent synergistic effects of Glycolic Acid, Salicylic Acid and Ethanol and eye irritation potential suggested by our results.

Influence of etchant type on the shear bond strength of orthodontic brackets to enamel.

The aim of this study was to evaluate the influence of the type of etchant on the shear bond strength (SBS) of metallic brackets to enamel and the Adhesive Remnant Index (ARI) after debonding. A total of 30 mandibular and maxillary premolars were randomly distributed into groups (n = 10) treated with 1 of 3 enamel surface-conditioning agents: 35% phosphoric acid (PA), 35% glycolic acid (GA), or 35% ferulic acid (FA). The designated acid was applied to the buccal enamel surface of the tooth for 20 seconds, and the tooth was then rinsed with distilled water for 20 seconds and air dried for 5 seconds. A metal bracket was bonded to the prepared surface with light-cured orthodontic resin. After 24 hours, the bracket-tooth interface was submitted to SBS testing in a universal testing machine at a speed of 0.5 mm/min. After debonding, the enamel surface was observed under a stereomicroscope (×20 magnification) to determine the ARI. The generalized linear models showed that the PA and GA groups presented significantly higher SBSs than the FA group (P = 0.0003). The ARI was significantly higher in specimens treated with PA than with the other acids (P < 0.05; Kruskal-Wallis and Dunn tests), with a larger quantity of adhesive remaining adhered to the tooth. Both PA and GA are effective for bonding brackets, but GA resulted in a lower percentage of adhesive remnant adhered to the enamel.