Biopsy for molecular risk stratification in uveal melanoma: Yields and molecular characteristics in 119 patients.

BACKGROUND: Prognostic cytological and molecular features of uveal melanoma have been well researched and are essential in management. Samples can be obtained in vivo through fine needle aspirate biopsy, vitrector cutter, forceps or post-enucleation for off-site testing. This study aims to examine cytological and chromosome microarray yields of these samples. METHODS: A retrospective cohort analysis of 119 uveal melanoma biopsies submitted to our laboratory. Samples included those taken in vivo (n = 57) and post-enucleation (n = 62). Patient and tumour features were collected including age, sex, primary tumour location, basal diameter and tumour height. Prognostic outcomes measured include cell morphology, chromosomal status and immunohistochemistry. RESULTS: Post-enucleation biopsies accounted for just over half of our samples (52%). Post-enucleation samples had a more successful genetic yield than in vivo biopsies (77% vs. 50%, p = 0.04) though there was no difference for cytological yields. There was no difference in cytological or microarray yields between instruments. The vitrector biopsy group had the smallest tumour thickness (5 mm vs. 10 mm [fine-needle aspirate biopsy], p = 0.003). There was a strong correlation between monosomy 3, BAP1 aberrancy and epithelioid cell type in post-enucleation samples (Tb  = 0.742, p = 0.005). However, epithelioid morphology was not associated with either monosomy 3 (p = 0.07) or BAP1 aberrancy (p = 0.24) for in vivo biopsies. CONCLUSIONS: All three biopsy instruments provide similar cytological yields as post-enucleation sampling, although post-enucleation samples had a more successful chromosome microarray yield. Epithelioid cytomorphology alone is insufficient for prognostication in in vivo biopsies, immunohistochemistry would be a useful surrogate test.

The Usefulness of Anti-acetylcholine Receptor Binding Antibody Testing in Diagnosing Ocular Myasthenia Gravis.

BACKGROUND: Anti-acetylcholine receptor antibody (AChR-Abs) testing is a safe and simple ancillary method for confirming the diagnosis of myasthenia gravis. Despite the test's high sensitivity (85%-90%) for generalized myasthenia gravis, AChR-Abs testing has been reported to have a low sensitivity 44%-66% for ocular myasthenia gravis (OMG). The aim of the study is to assess the effectiveness of AChR binding Abs testing for diagnosing OMG by evaluating the test's sensitivity, specificity, positive predictive value, and negative predictive value. METHODS: A retrospective chart review on 114 OMG suspects who presented to the emergency department of a tertiary eye center in Victoria, Australia, was completed. The patients presented with diplopia alone, ptosis alone, or the combination of diplopia and ptosis. All participants were followed up longitudinally in the neuro-ophthalmology outpatient clinics for the average of 2.8 months, where they have received AChR binding testing. The final diagnosis was only given to the patients who either were seropositive for AChR binding Abs and had a high clinical suspicion of OMG, or the patient who was seronegative for AChR binding Abs but was regarded as likely to have OMG clinically and responded to the diagnostic treatments (pyridostigmine bromide and immunosuppressant therapy). RESULTS: The sensitivity of AChR binding Abs testing in diagnosing OMG was higher (80%; 95% confidence interval [CI], 51.91%-95.67%) than previously reported (44%-66%). AChR binding Abs testing also had a high specificity (98.99%; 95% CI, 94.50%-99.97%) and positive predictive value (92.31%; 95% CI, 62.68%-98.85%). CONCLUSION: The study suggests the higher utility of the AChR binding Abs testing in diagnosing OMG due to its high sensitivity, specificity, and positive predictive value.

Evaluation of the efficacy of cysteamine cream compared to hydroquinone in the treatment of melasma: A randomised, double-blinded trial.

BACKGROUND/OBJECTIVE: Melasma is a commonly acquired disorder of hyperpigmentation that often poses a therapeutic challenge for dermatologists. Recently, cysteamine cream has shown promising results compared to placebo. This study aims to determine the efficacy of cysteamine cream compared to hydroquinone cream in the treatment of melasma. METHODS: A randomised, double-blinded, single-centre trial was conducted in Victoria, Australia. 20 recruited participants were given either cysteamine cream or hydroquinone cream for 16 weeks. The primary outcome measure was a change in the modified Melasma Area and Severity Index (mMASI). Quality of life at baseline and week 16 as well as standard digital photography at each follow-up visit was assessed as secondary outcome measures. RESULTS: At week 16, 14 participants completed the study with 5 participants in the cysteamine group and 9 patients in the hydroquinone group. In the intention to treat analysis, there was a 1.52 ± 0.69 (21.3%) reduction in mMASI for the cysteamine group and a 2.96 ± 1.15 (32%) reduction in the hydroquinone group. The difference between groups was not statistically significant (P = 0.3). Hydroquinone cream was generally better tolerated that cysteamine cream. CONCLUSION: Our study suggests that topical cysteamine may have comparable efficacy to topical hydroquinone. Cysteamine thus provides a possible alternative to patients and clinicians who wish to avoid or rotate off topical hydroquinone. While side effects were more common for participants using cysteamine compared with hydroquinone, these were mild and reversible. Larger studies comparing cysteamine and hydroquinone are required to support these findings.

Eyelid basal cell carcinoma with neuroendocrine differentiation: a case report and literature review.

Basal cell carcinoma (BCC) is the most common type of malignant tumor in the periocular region. BCCs with neuroendocrine differentiation in the periocular region, however, have not been described in the literature.We present a retrospective case review of a patient with an eyelid BCC with neuroendocrine differentiation. Demographical, clinical, radiological, surgical, histological, and follow-up data are presented.The patient presented with a slow-growing lesion of the eyelid with associated epiphora and dull ache. Initial incisional biopsy of the lesion revealed an infiltrating carcinoma composed of epithelial cells. Immunohistochemistry showed that the tumor was positive for p40, Ber-Ep4, neuron specific enolase (NSE), chromogranin A, CD56 (NCAM), and synaptophysin. The pathology from the margin-controlled excision showed basosquamous cell carcinoma with neuroendocrine differentiation. Tumor recurrence was not detected clinically at the post-operative six-month review.BCC with neuroendocrine marker positivity represents an important diagnostic differential for rare eyelid carcinomas such as primary cutaneous neuroendocrine carcinoma and metastatic small cell carcinoma that have a poor prognosis. The prognostic importance of neuroendocrine marker positivity in BCCs is uncertain. The present case provides further evidence for neuroendocrine differentiation in BCCs.

One-Year Results of Treatment of Diabetic Macular Edema with Aflibercept Using the Treat-and-Extend Dosing Regimen: the VIBIM Study.

INTRODUCTION: The purpose of this study was to report the one-year results of treatment of diabetic macular edema (DME) with aflibercept using a treat-and-extend regimen (TER). METHODS: This was a prospective, multicenter, single-arm study planned for 2 years. The eyes received 5 consecutive intravitreal injections of 2 mg of aflibercept every 4 weeks, and the interval between injections was then adjusted by 2 weeks based on changes in the central subfield macular thickness (CSMT). If the CSMT was worse, stable, or better, the interval was shortened, extended, or maintained, respectively. The primary outcome measure was the change in best-corrected visual acuity (BCVA) from baseline to 104 weeks, and the secondary outcome was the change in BCVA from baseline to 52 weeks. RESULTS: Of the 48 patients enrolled, 46 completed a 1-year visit. BCVA improved significantly by 9.1 letters (95% confidence interval: 5.3-13.0 letters) from 56.2 letters at baseline (p < 0.001), and CSMT decreased by -171.7 µm from 489.4 to 317.7 µm (p < 0.001). The proportion of eyes having 20/40 or better vision increased from 17.4 to 41.3%, and the proportion of eyes that gained ≥15 letters was 28.3%. The mean number of injections was 8.5 times for 52 weeks. Worsening of macular edema did not occur in 76.1% of eyes during the extension period, and the interval between injections was extended to 12 weeks in 73.9% of eyes at 52 weeks. CONCLUSIONS: The TER showed 1-year efficacy comparable to that of the fixed dosing regimen of pivotal trials, and its flexible dosing would prevent overtreatment.

Structural details of the OxyR peroxide-sensing mechanism.

OxyR, a bacterial peroxide sensor, is a LysR-type transcriptional regulator (LTTR) that regulates the transcription of defense genes in response to a low level of cellular H2O2. Consisting of an N-terminal DNA-binding domain (DBD) and a C-terminal regulatory domain (RD), OxyR senses H2O2 with conserved cysteine residues in the RD. However, the precise mechanism of OxyR is not yet known due to the absence of the full-length (FL) protein structure. Here we determined the crystal structures of the FL protein and RD of Pseudomonas aeruginosa OxyR and its C199D mutant proteins. The FL crystal structures revealed that OxyR has a tetrameric arrangement assembled via two distinct dimerization interfaces. The C199D mutant structures suggested that new interactions that are mediated by cysteine hydroxylation induce a large conformational change, facilitating intramolecular disulfide-bond formation. More importantly, a bound H2O2 molecule was found near the Cys199 site, suggesting the H2O2-driven oxidation mechanism of OxyR. Combined with the crystal structures, a modeling study suggested that a large movement of the DBD is triggered by structural changes in the regulatory domains upon oxidation. Taken together, these findings provide novel concepts for answering key questions regarding OxyR in the H2O2-sensing and oxidation-dependent regulation of antioxidant genes.

Efficacy of fixed-dosing aflibercept for treating polypoidal choroidal vasculopathy: 1-year results of the VAULT study.

PURPOSE: To investigate fixed-dosing aflibercept for treating polypoidal choroidal vasculopathy (PCV). METHODS: This phase IV, prospective, single-arm, interventional case series was conducted in eight centers. Forty treatment-naïve PCV patients were administered three monthly doses of intravitreal aflibercept (2.0 mg) and an injection every 2 months thereafter. Best-corrected visual acuity (BCVA) and central subfield macular thickness (CSMT) were measured at each visit. Fluorescein and indocyanine green angiography (ICGA) were performed at baseline, 3 and 12 months. The primary outcome measure was the proportion of patients who maintained BCVA (<15 letters loss) at 12 months. Changes in BCVA, macular appearance, and polypoidal lesion appearance were also examined. RESULTS: Thirty-five eyes (87.5 %) had maintained BCVA at 12 months. Average BCVA was significantly higher at 12 months (20/53, 64.2 letters) than at baseline (20/80, 55.1 letters, 9-letter gain; P < .001). Mean CSMT was significantly lower at 12 months (253.6 µm) than at baseline (365.2 µm, P < .001). The macula was dry in 32 (76.2 %), 27 (64.3 %), and 24 eyes (60.0 %) at 3, 6, and 12 months respectively. Fourteen eyes (33.3 %) had a fluid recurrence or increase at 6 months, and they had a significantly lower vision gain (P = .005) than other patients at 12 months. Complete polyp regression occurred in 26 eyes (66.7 %) at 12 months. CONCLUSIONS: Fixed-dosing aflibercept showed favorable outcomes in PCV patients at 12 months. However, some patients had worse outcomes because of fluid recurrence during maintenance dosing, and these patients would require additional treatments.

TOPOGRAPHIC CHANGES OF THE MACULA AFTER CLOSURE OF IDIOPATHIC MACULAR HOLE.

PURPOSE: To investigate retinal displacement in the macula after surgical closure of idiopathic macular hole and to identify factors correlated with displacement. METHODS: This retrospective multicenter study included 73 eyes of 73 patients having idiopathic macular hole. A custom program was developed to compare the position of the retinal vessels in the macula between preoperative and postoperative photographs. En face images of a 6 mm × 6 mm optical coherence tomography volume scans were registered to calculate the scale. A grid comprising 16 sectors in 2 rings (inner; 2-4 mm and outer; 4-6 mm) was superimposed. The displacement of the retinal vessels was measured as a vector value by comparing the location of the retinal vessels in each sector. The correlation between displacement and various clinical parameters was analyzed. RESULTS: The average displacement was 57.2 µm at an angle of -3.3° (nasal and slightly inferior). Displacement was larger in the inner ring (79.2 µm) than in the outer ring (35.3 µm, P < 0.001), and larger in the temporal sectors than in the corresponding nasal sectors (P ≤ 0.008). Inferior and superior displacement was noted in the superior and inferior sectors, respectively. Multiple regression analysis revealed that basal horizontal macular hole diameter and size of internal limiting membrane removal were independent factors of displacement. CONCLUSION: The macula was displaced centripetally, nasally, and slightly inferiorly after surgical closure of idiopathic macular hole. Hole closure, contraction of the nerve fiber layer, and gravity are the suggested mechanisms of macular displacement caused by internal limiting membrane peeling.

Ascorbic acid concentrations in aqueous humor after systemic vitamin C supplementation in patients with cataract: pilot study.

BACKGROUND: To measure ascorbic acid concentration in aqueous humor of patients with cataract after oral or intravenous vitamin C supplementation. METHODS: Forty-two eyes of 42 patients with senile cataract who underwent uncomplicated cataract surgery were enrolled. Patients (n = 14 each) were administered oral vitamin C (2 g), intravenous vitamin C (20 g) or no treatment (control group) on the day before surgery. Samples of aqueous humor (0.1 cm3) were obtained by anterior chamber aspiration at the beginning of surgery and stored at -80 °C. Ascorbic acid concentration in aqueous humor was measured by high-pressure liquid chromatography. RESULTS: The mean age at surgery was 62.5 years, with no difference among the three groups. The mean ± standard deviation concentrations of ascorbic acid in aqueous humor in the control and oral and intravenous vitamin C groups were 1347 ± 331 µmol/L, 1859 ± 408 µmol/L and 2387 ± 445 µmol/L, respectively. Ascorbic acid concentration was significantly lower in the control than in the oral (P < 0.01) and intravenous (P < 0.001) vitamin C groups and was significantly higher in the intravenous than in the oral vitamin C group (P < 0.05). CONCLUSIONS: Ascorbic acid concentration in aqueous humor is increased by systemic vitamin C supplementation, with intravenous administration being more effective than oral administration.

A phage protein that inhibits the bacterial ATPase required for type IV pilus assembly.

Type IV pili (TFPs) are required for bacterial twitching motility and for phage infection in the opportunistic human pathogen Pseudomonas aeruginosa. Here we describe a phage-encoded protein, D3112 protein gp05 (hereafter referred to as Tip, representing twitching inhibitory protein), whose expression is necessary and sufficient to mediate the inhibition of twitching motility. Tip interacts with and blocks the activity of bacterial-encoded PilB, the TFP assembly/extension ATPase, at an internal 40-aa region unique to PilB. Tip expression results in the loss of surface piliation. Based on these observations and the fact that many P. aeruginosa phages require TFPs for infection, Tip-mediated twitching inhibition may represent a generalized strategy for superinfection exclusion. Moreover, because TFPs are required for full virulence, PilB may be an attractive target for the development of novel antiinfectives.

Nontarget screening using passive air and water sampling with a level II fugacity model to identify unregulated environmental contaminants.

It is thought that there are many unregulated anthropogenic chemicals in the environment. For risk assessment of chemicals, it is essential to estimate the predicted environmental concentrations. As an effort of identifying residual organic contaminants in air and water in Korea, nontarget screening using two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) was conducted at 10 sites using polyurethane foam passive air sampler and at 6 sites using polydimethyl siloxane (PDMS) passive water sampler in three different seasons in 2014. More than 600 chemical peaks were identified satisfying the identification criteria in air and water samples, respectively, providing a list for further investigation. Chemical substances with reported national emission rates in 2014 (n=149) were also screened for potential existence in the environment using a level II fugacity model. Most of chemical substances classified as not detectable were not identified with detection frequency greater than 20% by nontarget screening, indicating that a simple equilibrium model has a strong potential to be used to exclude chemicals that are not likely to remain in the environment after emissions from targeted monitoring.

Comparison of the most common isolates of postoperative endophthalmitis in South Korea; Enterococcus species vs coagulase-negative staphylococci.

BACKGROUND: To compare the related factors or manifestations of the two most common isolates of post-operative endophthalmitis, which were Enterococcus spp. and coagulase-negative staphylococci (CNS) in South Korea. METHODS: Medical records were reviewed for cases of post-operative endophthalmitis caused by Enterococcus spp. and CNS at eight institutions between January 2004 and July 2010. Various factors including age, sex, residence, systemic diseases, smoking and drinking history, and best corrected visual acuity, and length of time between causative intraocular surgery and symptom development were compared between the two groups. RESULTS: The total number of post-operative endophthalmitis cases was 128 and in 116 cases, microbiological culture tests from the aqueous humor or vitreous were performed. Among these cases, 67 (57.8%) were culture proven. Among these 67 cases, 19 (28.4%) were caused by Enterococcus spp., 14 (20.9%) were caused by Staphylococcus epidermidis endophthalmitis, and 5 (7.5%) were caused by other CNS spp. Age, sex, causative procedure, past medical history, social history, and laterality were not different in the two groups. Mean initial and final visual acuity were significantly worse in the Enterococcus spp. endophthalmitis group than in the CNS group (p = 0.049, 0.042, respectively). Length of time between the causative procedure and symptom development was significantly shorter in cases of Enterococcus spp. endophthalmitis (p = 0.004). CONCLUSIONS: Enterococcus spp. induce more severe and rapid-onset postoperative endophthalmitis than CNS. Infectious endophthalmitis developed within 2 days after cataract operation could be caused by Enterococcus spp. and have chance to be poor prognosis in South Korea.

Clinical features of infectious endophthalmitis in South Korea: a five-year multicenter study.

BACKGROUND: To investigate clinical features of infectious endophthalmitis over five years in a South Korean population. METHODS: Medical records of consecutive patients diagnosed with infectious endophthalmitis at eight institutions located in Gyeongsangnam-do and Pusan city between January 1, 2004 and July 31, 2010 were reviewed. RESULTS: A total of 197 patients were diagnosed and treated. An average of 30.0 infectious endophthalmitis per year was developed. The annual incidence rate of postoperative endophthalmitis during 2006~2009 was 0.037%. The ratios of male to female and right to left were 50.2%: 49.8 % and 54.8%: 43.2%, respectively. Eighth decade and spring were the peak age (36.6%) and season (32.0%) to develop the infectious endophthalmitis. The most common past history in systemic disease was hypertension (40.4%), followed by diabetes (23.4%). Cataract operation (60.4%) was the most common cause, among which most of them was uneventful phacoemulsification (95.9%). Corneal laceration (51.6%) and liver abscess (42.9%) were the most common causes of traumatic and endogenous endophthalmitis, respectively. The percentages of patients with initial and final visual acuity less than counting fingers were 62.6% and 35.2%, respectively. Treatment with vitrectomy with or without intravitreal antibiotics injection was administered to 72.6% of patients, while 17.3% received intravitreal antibiotics only. CONCLUSIONS: Our study revealed that the development of infectious endophthalmitis was related with seasonal variation and increased during our study period. Pars plana vitrectomy was preferred for the treatment of infectious endophthalmitis in South Korea.

A case of phacolytic glaucoma with anterior lens capsule disruption identified by scanning electron microscopy.

BACKGROUND: Phacolytic glaucoma is induced by lens protein or macrophages that have leaked through a macroscopically intact anterior lens capsule. Here, we report a case of phacolytic glaucoma with anterior lens capsule disruptions visualized by scanning electron microscopy (SEM). CASE PRESENTATION: A 71-year-old man was referred to our institute for increased intraocular pressure (IOP) in the right eye. Slit-lamp biomicroscopic examination revealed corneal edema, the presence of inflammatory cells and iridescent crystalline in the anterior chamber, and a hypermature cataract in the right eye. Despite treatment with topical glaucoma medication (0.15% brimonidine, 1% brinzolamide/0.5% timolol, and 0.03% bimatoprost) and systemic mannitol, his IOP remained uncontrolled. Light microscopy was used to examine the aqueous humor obtained via anterior chamber paracentesis and the anterior lens capsule obtained via intracapsular cataract extraction (ICCE), which revealed that the anterior lens capsule was intact. However, SEM revealed full-thickness disruptions in the anterior lens. CONCLUSION: This is the first reported case of phacolytic glaucoma with disruptions of the anterior lens capsule confirmed by SEM.

Dysthyroid optic neuropathy: a case series at a tertiary ophthalmic referral centre.

BACKGROUND/OBJECTIVES: To determine risk factors and treatment outcomes in dysthyroid optic neuropathy (DON) at a single tertiary ophthalmic centre. METHODS: Retrospective audit of DON patients who have received intravenous methylprednisolone (IVMP) therapy at Royal Victorian Eye and Ear Hospital, Melbourne, Australia from July 2015 to October 2021. RESULTS: Study included 24 patients (58% female) with an average age of 59.8 ± 14.7 years at DON diagnosis. Majority (92%) had Graves' hyperthyroidism and 77% had a smoking history. At diagnosis, average visual acuity (VA) of worse eye was LogMAR 0.46, and 48% had relative afferent pupillary defect. Proptosis (89%) and diplopia (73%) were most commonly present at diagnosis. 78% showed predominantly extra-ocular muscle enlargement, and apical crowding (52%) on radiology. 38% (n = 9/24) responded to IVMP alone, 58% (n = 14/24) progressed to surgical orbital decompression. The average total cumulative dose of IVMP during DON treatment was 6.8 ± 1.9 g. 29% required further treatment after IVMP and surgical decompression, 4 (17%) had additional radiotherapy, and three (13%) required immuno-modulatory therapy. Average final VA was LogMAR 0.207, with all patients having inactive TED at final follow-up (mean 1.7 years). In refractory DON cases, 71% retained VA ≥ 6/9 and 48% had DON reversal. CONCLUSIONS: DON patients typically present in late 50s, with a smoking history and predominant extra-ocular muscle enlargement. High-dose IVMP fully resolved DON in only 38%. A considerable proportion required urgent orbital decompression. Most patients retained good vision at final follow-up.

The Microbiome Matters: Its Impact on Cancer Development and Therapeutic Responses.

In the evolving landscape of cancer research, the human microbiome emerges as a pivotal determinant reshaping our understanding of tumorigenesis and therapeutic responses. Advanced sequencing technologies have uncovered a vibrant microbial community not confined to the gut but thriving within tumor tissues. Comprising bacteria, viruses, and fungi, this diverse microbiota displays distinct signatures across various cancers, with most research primarily focusing on bacteria. The correlations between specific microbial taxa within different cancer types underscore their pivotal roles in driving tumorigenesis and influencing therapeutic responses, particularly in chemotherapy and immunotherapy. This review amalgamates recent discoveries, emphasizing the translocation of the oral microbiome to the gut as a potential marker for microbiome dysbiosis across diverse cancer types and delves into potential mechanisms contributing to cancer promotion. Furthermore, it highlights the adverse effects of the microbiome on cancer development while exploring its potential in fortifying strategies for cancer prevention and treatment.

Autolysis of Pseudomonas aeruginosa Quorum-Sensing Mutant Is Suppressed by Staphylococcus aureus through Iron-Dependent Metabolism.

Microorganisms usually coexist as a multifaceted polymicrobial community in the natural habitats and at mucosal sites of the human body. Two opportunistic human pathogens, Pseudomonas aeruginosa and Staphylococcus aureus commonly coexist in the bacterial infections for hospitalized and/or immunocompromised patients. Here, we observed that autolysis of the P. aeruginosa quorum-sensing (QS) mutant (lasRmvfR) was suppressed by the presence of the S. aureus cells in vitro. The QS mutant still displayed killing against S. aureus cells, suggesting the link between the S. aureus-killing activity and the autolysis suppression. Independent screens of the P. aeruginosa transposon mutants defective in the S. aureus-killing and the S. aureus transposon mutants devoid of the autolysis suppression revealed the genetic link between both phenotypes, suggesting that the iron-dependent metabolism involving S. aureus exoproteins might be central to both phenotypes. The autolysis was suppressed by iron treatment as well. These results suggest that the interaction between P. aeruginosa and S. aureus might be governed by mechanisms that necessitate the QS circuitry as well as the metabolism involving the extracellular iron resources during the polymicrobial infections in the human airway.

Evaluation of inhalation risk during quarantine work with quaternary ammonium compounds-based disinfectant.

Quarantine work is widely recognized as an indispensable endeavor in curbing the propagation of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Furthermore, the heavy workload places workers at a heightened risk of chemical exposure and respiratory damage. Consequently, it is paramount to systematically perform health risk assessments and meticulously oversee the work by wearing personal protective equipment to minimize these risks. To assess the inhalation exposure, this study examined data on disinfectant exposure from quarantine professional users who utilized disinfectants containing quaternary ammonium compounds. Through a survey of 6,199 cases conducted by 300 quarantine professional users who actively engaged in quarantine work, we assembled a database of exposure factors derived from their utilization of spray-type disinfectants for quarantine purposes. Based on these data, we formulated an inhalation exposure algorithm, which considers the time-weighted average (TWA) air concentrations. The test results demonstrated that the industrial-grade respirator mask could prevent a minimum of 68.3 % of particles, reducing respiratory exposure. Consequently, the hazard quotient (HQ) due to disinfectant exposure also decreased. This research is essential in safeguarding the safety and health of professional users engaged in quarantine-related tasks. By implementing strict measures like health risk assessments and personal protective equipment, individuals with quarantine experience can safely carry out their quarantine work. The results of this study are expected to serve as a framework for improving policies and regulations concerning quarantine work and safeguarding the health of professional users.

A TetR family regulator of an RND efflux system that directs artemisinin resistance in Vibrio cholerae.

Artemisinin (ARS) displayed bactericidal activity against Vibrio cholerae. To assess the mechanistic details of its antibacterial action, we have isolated V. cholerae mutants with enhanced ARS resistance and identified a gene (VCA0767) whose loss-of-function resulted in the ARS resistance phenotypes. This gene (atrR) encodes a TetR family transcriptional regulator, and its deletion mutant displayed the reduction in ARS-induced ROS formation and DNA damage. Transcriptomic analysis revealed that the genes encoding a resistance-nodulation-cell division (RND) efflux pump operon (vexRAB) and the outer membrane component (tolC) were highly upregulated in the artR mutant, suggesting that AtrR might act as a negative regulator of this operon and tolC. Gene deletion of vexR, vexB, or tolC abrogated the ARS resistance of the atrR mutant, and more importantly, the ectopic expression of VexAB-TolC was sufficient for the ARS resistance, indicating that the increased expression of the VexAB-TolC efflux system is necessary and sufficient for the ARS resistance of the atrR mutant. The cytoplasmic accumulation of ARS was compromised in the vexBtolC mutant, suggesting that the VexAB-TolC might be the primary efflux system exporting ARS to reduce its toxicity inside of the bacterial cells. The atrR mutant displayed resistance to erythromycin as well in a VexR-dependent manner. This result suggests that AtrR may act as a global regulator responsible for preventing intracellular accumulation of toxic chemicals by enhancing the RND efflux system.IMPORTANCEDrug efflux protein complexes or efflux pumps are considered as the major determinants of multiple antimicrobial resistance by exporting a wide range of structurally diverse antibiotics in bacterial pathogens. Despite the clinical significance of the increased expression of the efflux pumps, their substrate specificity and regulation mechanisms are poorly understood. Here, we demonstrated that VexAB-TolC, a resistance-nodulation-cell division (RND) efflux pump of V. cholerae, is responsible for the resistance to artemisinin (ARS), an antimalarial drug with bactericidal activity. Furthermore, we newly identified AtrR, a TetR family repressor, as a global regulator for VexRAB and the common outer membrane channel, TolC, where VexR functions as the pathway-specific regulator of the vexAB operon. Our findings will help improve our insight into a broad range of substrate specificity of the VexAB-TolC system and highlight the complex regulatory networks of the multiple RND efflux systems during V. cholerae pathogenesis.

Complete genome sequences of two Pseudomonas aeruginosa temperate phages, MP29 and MP42, which lack the phage-host CRISPR interaction.

We report the complete genome sequence of two Pseudomonas aeruginosa phages MP29 and MP42. Their genomes are similar to those of P. aeruginosa temperate phages DMS3 and MP22, whose lysogens are impaired in swarming motilities, involving the host CRISPR loci. Both MP29 and MP42 lysogens, however, were proficient in swarming, suggesting the absence of the phage-host CRISPR interaction.