The metabolite vanillic acid regulates Acinetobacter baumannii surface attachment.

The nosocomial bacterium Acinetobacter baumannii is protected from antibiotic treatment by acquiring antibiotic resistances and by forming biofilms. Cell attachment, one of the first steps in biofilm formation, is normally induced by environmental metabolites. We hypothesized that vanillic acid (VA), the oxidized form of vanillin and a widely available metabolite, may play a role in A. baumannii cell attachment. We first discovered that A. baumannii actively breaks down VA through the evolutionarily conserved vanABKP genes. These genes are under the control of the repressor VanR, which we show binds directly to VanR binding sites within the vanABKP genes bidirectional promoter. VA in turn counteracts VanR inhibition. We identified a VanR binding site and searched for it throughout the genome, especially in pili encoding promoter genes. We found a VanR binding site in the pilus encoding csu operon promoter and showed that VanR binds specifically to it. As expected, a strain lacking VanR overproduces Csu pili and makes robust biofilms. Our study uncovers the role that VA plays in facilitating the attachment of A. baumannii cells to surfaces, a crucial step in biofilm formation. These findings provide valuable insights into a previously obscure catabolic pathway with significant clinical implications.

RecA levels modulate biofilm development in Acinetobacter baumannii.

Infections caused by Acinetobacter baumannii, a Gram-negative opportunistic pathogen, are difficult to eradicate due to the bacterium's propensity to quickly gain antibiotic resistances and form biofilms, a protective bacterial multicellular community. The A. baumannii DNA damage response (DDR) mediates the antibiotic resistance acquisition and regulates RecA in an atypical fashion; both RecALow and RecAHigh cell types are formed in response to DNA damage. The findings of this study demonstrate that the levels of RecA can influence formation and dispersal of biofilms. RecA loss results in surface attachment and prominent biofilms, while elevated RecA leads to diminished attachment and dispersal. These findings suggest that the challenge to treat A. baumannii infections may be explained by the induction of the DDR, common during infection, as well as the delicate balance between maintaining biofilms in low RecA cells and promoting mutagenesis and dispersal in high RecA cells. This study underscores the importance of understanding the fundamental biology of bacteria to develop more effective treatments for infections.

Mucosal vaccination in a murine gnotobiotic model of Giardia lamblia infection.

Giardia lamblia is an important protozoan cause of diarrheal disease worldwide, delayed development and cognitive impairment in children in low- and middle-income countries, and protracted post-infectious syndromes in developed regions. G. lamblia resides in the lumen and at the epithelial surface of the proximal small intestine but is not mucosa invasive. The protozoan parasite is genetically diverse with significant genome differences across strains and assemblages. Animal models, particularly murine models, have been instrumental in defining mechanisms of host defense against G. lamblia, but mice cannot be readily infected with most human pathogenic strains. Antibiotic pretreatment can increase susceptibility, suggesting that the normal microbiota plays a role in controlling G. lamblia infection in mice, but the broader implications on susceptibility to diverse strains are not known. Here, we have used gnotobiotic mice to demonstrate that robust intestinal infection can be achieved for a broad set of human-pathogenic strains of the genetic assemblages A and B. Furthermore, gnotobiotic mice were able to eradicate infection with a similar kinetics to conventional mice after trophozoite challenge. Germ-free mice could also be effectively immunized by the mucosal route with a protective antigen, α1-giardin, in a manner dependent on CD4 T cells. These results indicate that the gnotobiotic mouse model is powerful for investigating acquired host defenses in giardiasis, as the mice are broadly susceptible to diverse G. lamblia strains yet display no apparent defects in mucosal immunity needed for controlling and eradicating this lumen-dwelling pathogen.

Natural Histories and Disease Complications in a Cohort of 151 Children With Gastric or Duodenal Eosinophilia.

INTRODUCTION: Eosinophilic gastritis (EoG) and duodenitis (EoD) are rare conditions that are poorly understood. Our aim was to describe the natural history of children with varying degrees of gastric or duodenal eosinophilia with respect to disease complications and histologic and endoscopic longitudinal trajectories. METHODS: The electronic medical record at a tertiary children's hospital was queried to identify patients with EoG, EoD, or EoG + EoD who were cared for between January 2010 and 2022. Multiple logistic regression was performed to explore associations between baseline features and persistence/recurrence of eosinophilia or complications remote from diagnosis. RESULTS: We identified 151 patients: 92 with EoG, 24 with EoD, 12 with EoG + EoD, and 23 with tissue eosinophilia but did not meet histologic criteria for EoG or EoD (low grade). The average age at diagnosis was 10.6 years, and average follow-up was 5.8 years. Twenty-five percent of patients with EoG or EoD had persistence/recurrence of eosinophilia; this was associated with increases in the EoG Endoscopic Reference Score (adjusted odds ratio [aOR] 1.34, confidence interval [CI] 1.03-1.74) on diagnostic endoscopy. Eighteen percent suffered from disease complications, and development of late complications was associated with presenting with a complication (aOR 9.63, CI 1.09-85.20), severity of duodenal endoscopic abnormalities (aOR 8.74, CI 1.67-45.60), and increases in the EoG Endoscopic Reference Score (aOR 1.70, CI 1.11-2.63). DISCUSSION: Patients with gastric and duodenal eosinophilia should be followed closely to monitor for recurrence and complications, especially those presenting with endoscopic abnormalities or complications.

Impact of Income-to-Poverty Ratio on Long-Term Mortality of Persons with Chronic Liver Disease in the US, 1999-2018.

INTRODUCTION: Chronic liver disease (CLD) is associated with increased morbidity and mortality. Understanding health disparities can inform appropriate interventions. We aimed to study mortality outcomes of those with CLD by income-level (income-to-poverty ratio <5 as lower-income and > 5 as higher-income). METHODS: In this retrospective-cohort study, we analyzed data of adults from the National Health and Nutrition Examination Survey, 1999-2018. CLD included viral hepatitis, nonalcoholic fatty liver disease (NAFLD), and alcohol-associated liver disease (ALD). RESULTS: We analyzed 59,204 adults: 47,224 without CLD and 11,980 with CLD. The CLD group was older, more likely male, racial/ethnic minority groups or foreign-born, and had lower educational and income levels (P<0.001). Most (80.02%) CLD participants did not have college degrees and had lower-income (79.18%). Among CLD participants, similar differences were observed between lower and higher-income groups. Lower-income participants with CLD had significantly higher 10-year cumulative mortality compared to higher-income CLD participants (15.26% vs 8.00%, P<0.001), with consistent findings in viral hepatitis and NAFLD subgroups (P<0.001) but not ALD (P=0.71). Adjusting for age, sex, race, birthplace, lower-income CLD participants were 2.01 (HR: 2.01; 95% CI: 1.79-2.26) times more likely to die overall and in viral hepatitis (HR: 2.05; 95% CI: 1.31-3.24) and NAFLD subgroups (HR: 2.32; 95% CI: 1.69-3.18) but not ALD (HR: 1.17; 95% CI: 0.55-2.51). CONCLUSION: Lower-income, foreign-born, and racial/ethnic minority groups were disproportionately represented among those with CLD, with lower-income and CLD individuals having double the mortality risk compared to their higher-income counterparts. Interventions should be culturally appropriate and address socioeconomic barriers.

Evaluation of a multidisciplinary, multimodal pain management protocol following pancreas transplantation.

INTRODUCTION: Patients undergoing solid-organ transplantation demonstrate pain arising from both the surgical intervention and pre-existing comorbidities. High levels of opioid use both pre- and post-transplant are associated with unfavorable transplant outcomes. Patient education, multimodal therapy, and discharge planning have all been demonstrated to reduce opioid use after transplant. METHODS: This is a single-center, retrospective study analyzing patients before and after implementation of a multimodal, multidisciplinary pain management protocol. Morphine milligram equivalents (MMEs) use during the index transplant hospitalization and the need for opioids at discharge was compared between the pre- and post-protocol groups. RESULTS: A total of 52 patients were included in the study, 31 in the pre and 21 in the post-protocol groups. Inpatient MME use was reduced from 135.5 to 67.5 MMEs after protocol implementation. Additionally, the number of patients discharged on opioids following transplant decreased from 90.3% to 47.6%. Pain scores, length of stay (LOS), and return of bowel function was not different between groups. CONCLUSION: The implementation of a multimodal, multidisciplinary pain management protocol significantly decreased opioid use during the post-surgical hospitalization and in the 6 months following transplantation. A combination of non-opioid analgesics, patient education, and discharge planning can be beneficial elements in pancreas transplant pain management.

Tissue Clearing To Localize Microplastics via Three-Dimensional Imaging of Whole Organisms.

Understanding the biological impacts of plastic pollution requires an effective methodology to detect unlabeled microplastics in environmental samples. Detecting unlabeled microplastics in an organism generally requires a digestion protocol, which results in the loss of spatial information on the distribution of microplastic within the organism and could lead to the disappearance of the smaller plastics. Fluorescence microscopy allows visualization of ingested microplastics but many labeling strategies are nonspecific and label biomass, thus limiting our ability to distinguish internalized plastics. While prelabeled plastics can be used to avoid nonspecific labeling, this approach precludes the detection of environmental microplastics in organisms. Also, using prelabeled microplastics can affect the viability of the organism and impact plastic uptake. Thus, a method was developed that employs nonspecific labeling with a tissue-clearing technique. Briefly, unlabeled microplastics are stained with a fluorescent dye after ingestion by the organism. The tissue-clearing technique then removes tissue-bound dye while rendering the structurally intact organism transparent. The internalized plastics remain stained and can be visualized in the cleared tissue with fluorescence microscopy. The technique is demonstrated using polystyrene beads in living aquatic organismsTigriopus californicusandDaphnia magnaand by spiking a model vertebrate (Cephalochordata) with different microplastics.

Mohs Micrographic Surgery for Facial Merkel Cell Carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare malignant cutaneous tumor with frequent metastases. They often appear in the face where cosmetic and functional outcome is critical. Mohs micrographic surgery (MMS) is a controlled intervention that optimizes negative margins without sacrificing tissue. OBJECTIVE: A comprehensive assessment of outcomes of MMS-treated facial MCC will help guide clinicians in surgical and medical management. METHODS & MATERIALS: Retrospective review identified facial MCC cases treated with MMS at a single institution from January 2005 to August 2020. Tumor characteristics and outcomes were recorded and descriptive and predictive analyses were performed. RESULTS: 34 cases were reviewed with a mean followup of 34.4 months. The most common sites were the forehead, cheek-jaw region, and nasal ala. 2 (5.9%) patients had local recurrence by a mean of 4.3 months. No documented variables were significantly associated with local recurrence. 8 (23.5%) patients had progression to metastasis by a mean of 9.4 months. Younger age at biopsy and surgery, male sex, and intraoperative detection of in-transit disease were significantly associated with progression to metastasis. CONCLUSIONS: In summary, the tissue-sparing approach of MMS may be beneficial for MCC in cosmetically and functionally sensitive facial locations as it preserves tissue without compromising outcomes.

Robotic Hepaticojejunostomy for Late Anastomotic Biliary Stricture After Liver Transplantation: Technical Description and Case Series.

Biliary strictures after liver transplantation are common and when refractive to endoscopic and percutaneous intervention require surgical revision. Robotic technology facilitates minimally invasive biliary reconstruction and has not previously been described after liver transplantation. Robotic biliary revisions were retrospectively compared to all the historical open cases over a time period from May 2013 to October 2020. During the study period there were 3 robotic and 4 open surgical biliary revisions with a follow-up of at least 6months. All cases were hepaticojejunostomies for late choledocho-choledochostomy anastomotic strictures presenting > 4 weeks after transplant and refractive to at least 3 endoscopic and/or percutaneous interventions. Median (range) case time was longer in the robotic group, 373 minutes (286-373) compared to open group, 280 minutes (163-321). The median length of stay was shorter in the robotic group, 4 days (1--4) compared to open group 7 days (4-10). Morbidity included 2 wound infections in the open group (grade II), 1 infected hematoma in the robotic group (grade Ilia), and 1 bile leak on the open group (grade Ilia). There was no biliary stricture recurrence or mortality in either group. Robotic biliary revision is a safe alternative to traditional open biliary revision for refractive biliary strictures after liver transplantation.

Single-Particle Resolution Fluorescence Microscopy of Nanoplastics.

Understanding of nanoplastic prevalence and toxicology is limited by imaging challenges resulting from their small size. Fluorescence microscopy is widely applied to track and identify microplastics in laboratory studies and environmental samples. However, conventional fluorescence microscopy, due to diffraction, lacks the resolution to precisely localize nanoplastics in tissues, distinguish them from free dye, or quantify them in environmental samples. To address these limitations, we developed techniques to label nanoplastics for imaging with stimulated emission depletion (STED) microscopy to achieve resolution at an order of magnitude superior to conventional fluorescence microscopy. These techniques include (1) passive sorption; (2) swell incorporation; and (3) covalent coupling of STED-compatible fluorescence dyes to nanoplastics. We demonstrate that our labeling techniques, combined with STED microscopy, can be used to resolve nanoplastics of different shapes and compositions as small as 50 nm. The longevity of dye labeling is demonstrated in different media and conditions of biological and environmental relevance. We also test STED imaging of nanoplastics in exposure experiments with the model worm Caenorhabditis elegans. Our work shows the value of the method for detection and localization of nanoplastics as small as 50 nm in a whole animal without disruption of the tissue. These techniques will allow more precise localization and quantification of nanoplastics in complex matrices such as biological tissues in exposure studies.

Improving safety of robotic major hepatectomy with extrahepatic inflow control and laparoscopic CUSA parenchymal transection: technical description and initial experience.

BACKGROUND: Blood loss is a major determinant of outcomes following hepatectomy. Robotic technology enables hepatobiliary surgeons to mimic open techniques for inflow control and parenchymal transection during major hepatectomy, increasing the ability to minimize blood loss and perform safe liver resections. METHODS: Initial experience of 20 consecutive major robotic hepatectomies from November 2018 to July 2020 at two co-located institutions was reviewed. All cases were performed with extrahepatic inflow control and parenchymal transection with the laparoscopic cavitron ultrasonic surgical aspirator (CUSA), and a technical description is illustrated. Clinical characteristics, operative data, and surgical outcomes were retrospectively analyzed. RESULTS: The median (range) patient age was 58 years (20-76) and the majority of 14 (70%) patients were ASA III-IV. There were 12 (60%) resections for malignancy and the median tumor size was 6.2 cm (1.2-14.6). Right or extended right hepatectomy was the most common procedure (12 or 60% of cases). There were 7 (35%) left or extended left hepatectomies and 1 (5%) central hepatectomy. The median operative time was 420 (177-622) minutes. Median estimated blood loss was 300 mL (25-800 mL). One (5%) case was converted to open. Two (10%) patients required blood transfusion. The median length of stay was 3 (1-6) days. Major complications included 1 (5%) Clavien-Dindo IIIa bile leak requiring percutaneous drainage placement. There was no 90-day mortality. CONCLUSION: Advanced techniques to reduce blood loss in robotic hepatectomy may optimize safety and minimize morbidity in these complex minimally invasive procedures.

Sebaceous Carcinoma of the Face Treated With Mohs Micrographic Surgery.

BACKGROUND: Mohs micrographic surgery (MMS) for sebaceous carcinoma (SC) may reduce local recurrence rates, but published case series have small cohorts and limited follow-up. Mohs micrographic surgery is particularly suitable for sensitive functional and cosmetic locations, such as the face, because it facilitates tissue conservation using complete peripheral and deep margin assessment before reconstruction. Coordinated care between Mohs and oculoplastic surgeons has not been described. OBJECTIVE: To assess rates of local recurrence and metastasis after MMS of facial SC and to describe coordinated care between Mohs and oculoplastic surgeons. MATERIALS AND METHODS: Retrospective review identified facial SC cases treated with MMS at a single institution from January 2005 to August 2020. Tumor characteristics and outcomes were recorded. Descriptive and predictive analyses were performed. RESULTS: Forty-nine cases were reviewed with a mean follow-up of 51 months. The most common sites were periorbital, infraorbital cheek, and nasal ala. No patients experienced regional recurrence after MMS. One patient with Muir-Torre syndrome developed metastatic recurrence (at 82.9 months). All patients underwent 2-stage reconstruction with dermatology-performed MMS and oculoplastic reconstruction. CONCLUSION: Collaboration between Mohs and oculoplastic surgeons with a tissue-sparing approach of MMS can reduce recurrence and optimize cosmesis and function for central facial SC.

Surveying the persistence of age- and gender-based restrictions on over-the-counter emergency contraception across pharmacies in Los Angeles County, CA.

BACKGROUND: Over-the-counter levonorgestrel emergency contraception (OTC EC) is safe and effective but underutilized for postcoital pregnancy prevention. Unnecessary restrictions imposed by pharmacies and pharmacy workers may impede EC uptake. OBJECTIVE: To assess the persistence of age- and gender-based barriers to OTC EC access among pharmacists and pharmacy staff across Los Angeles, CA. METHODS: We conducted a cross-sectional survey of registered community pharmacies randomly chosen from regions with the highest unintended pregnancy rates in Los Angeles County. Using an adaptation of the 2017 American Society for Emergency Contraception EC Access and Price Survey, we interviewed pharmacy staff about their attitudes and practices related to OTC EC, with attention to age- and gender-based barriers. RESULTS: We surveyed 139 staff members (45% pharmacists, 20% technicians, 26% retail) from 93 publicly accessible pharmacies. Thirteen pharmacies did not stock EC. Half of respondents cited age-based restrictions; only 4% noted gender-based restrictions. More than 75% reported being asked for EC by a man; 7% reported refusing to sell to a man. Nearly 40% reported that men never or rarely purchased EC. Pharmacists were more likely than technicians or retail staff to believe men rarely purchased EC (P = 0.01). The most frequently cited concern about selling to men was inability to confirm the female partner's age. CONCLUSION: Although gender-based restrictions to EC are rare, more than half of pharmacy staff continue to report age-based restrictions. Inability to verify the female partner's age may underlie cases where men are unable to purchase OTC EC.

Gender bias in the medical education of obstetrician-gynaecologists in the United States: A systematic review.

BACKGROUND: The number of men entering obstetrics and gynaecology (Ob/Gyn) residencies and general Ob/Gyn practice is decreasing. Gender biases against their participation may affect career decisions. OBJECTIVE: This systematic review examines: (i) female patients' gender preferences and perceptions of men as Ob/Gyns and/or medical students; and (ii) the influence of gender on students' education and career decisions. SEARCH STRATEGY: We identified relevant research via PubMed using variations of three concepts in combination: Ob/Gyn care, gender bias/preference, and medical education or career. We conducted the initial review in 2018 and repeated the search in March 2021, adding additional references via citation review of included research. SELECTION CRITERIA: We restricted the review to original research from the United States between 2000-2021. DATA COLLECTION: Fifteen studies met inclusion criteria, categorised into three groups: (i) patient's gender preference for Ob/Gyns; (ii) patient's gender preference for medical students during the Ob/Gyn clerkship; and (iii) influence of gender bias on Ob/Gyn career decisions. MAIN RESULTS: Patients prioritised their physician's care attributes (eg technical skill, compassion, experience) over gender when choosing Ob/Gyns; however, provider gender was prioritised for medical students. Male medical students more commonly reported exclusion from clinical opportunities, although objective clinical exposure was like that of female counterparts. Despite perceived gender bias, male medical students reported increased Ob/Gyn interest post-clerkship; interest did not translate into residency applications. These findings are limited by study quality and heterogeneity. CONCLUSIONS: Real and perceived gender bias among female patients and male medical students in Ob/Gyn may underlie declining numbers of men entering the field.

Strong Ferromagnetic Exchange Coupling and Single-Molecule Magnetism in MoS43--Bridged Dilanthanide Complexes.

We report the synthesis and characterization of the trinuclear 4d-4f compounds [Co(C5Me5)2][(C5Me5)2Ln(µ-S)2Mo(µ-S)2Ln(C5Me5)2], 1-Ln (Ln = Y, Gd, Tb, Dy), containing the highly polarizable MoS43- bridging unit. UV-Vis-NIR diffuse reflectance spectra and DFT calculations of 1-Ln reveal a low-energy metal-to-metal charge transfer transition assigned to charge transfer from the singly occupied 4dz2 orbital of MoV to the empty 5d orbitals of the lanthanides (4d in the case of 1-Y), mediated by sulfur-based 3p orbitals. Electron paramagnetic resonance spectra collected for 1-Y in a tetrahydrofuran solution show large 89Y hyperfine coupling constants of A⊥ = 23 MHz and A|| = 26 MHz, indicating the presence of significant yttrium-localized unpaired electron density. Magnetic susceptibility data support similar electron delocalization and ferromagnetic Ln-Mo exchange for 1-Gd, 1-Tb, and 1-Dy. This ferromagnetic exchange gives rise to an S = 15/2 ground state for 1-Gd and one of the largest magnetic exchange constants involving GdIII observed to date, with JGd-Mo = +16.1(2) cm-1. Additional characterization of 1-Tb and 1-Dy by ac magnetic susceptibility measurements reveals that both compounds exhibit slow magnetic relaxation. Although a Raman magnetic relaxation process is dominant for both 1-Tb and 1-Dy, an extracted thermal relaxation barrier of Ueff = 68 cm-1 for 1-Dy is the largest yet reported for a complex containing a paramagnetic 4d metal center. Together, these results provide a potentially generalizable route to enhanced nd-4f magnetic exchange, revealing opportunities for the design of new nd-4f single-molecule magnets and bulk magnetic materials.

Cure With Interferon-Free Direct-Acting Antiviral Is Associated With Increased Survival in Patients With Hepatitis C Virus-Related Hepatocellular Carcinoma From Both East and West.

BACKGROUND AND AIMS: Survival data among patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) after achieving sustained virologic response (SVR) with interferon-free direct-acting antivirals (DAAs) in both Asian and western countries are limited. Survival rates were compared between patients with HCV-related HCC who were untreated for HCV and those who achieved SVR. APPROACH AND RESULTS: Using data from two U.S. and six Asian centers from 2005 to 2017, we categorized 1,676 patients who were mono-infected with HCV-related HCC into patients untreated for HCV (untreated group) and DAA-treated patients with SVR (SVR group) and matched by propensity score matching (PSM); multivariable Cox regression with HCV treatment status as a time-varying covariate was used to determine mortality risk and landmark analysis to avoid immortal time bias. There were 1,239 untreated patients and 437 patients with SVR. After PSM, background risks of the 321 pairs of matched patients were balanced (all P > 0.05). After time-varying adjustment for HCV treatment initiation compared with untreated patients, patients with SVR had significantly higher 5-year overall survival (87.78% vs. 66.05%, P < 0.001). Multivariable Cox regression showed that SVR was independently associated with a 63% lower risk of 5-year all-cause mortality (hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.16-0.83; P = 0.016) and 66% lower risk of 5-year liver-related mortality (HR, 0.34; 95% CI, 0.13-0.88; P = 0.026) with similar trends after removing patients with liver transplants. Landmark analysis at 90, 180, and 360 days showed consistent results (HRs ranged 0.22 to 0.44, all P < 0.05). CONCLUSION: In this multinational consortium, patients with HCV-related HCC who obtained SVR achieved a 60%-70% improvement in 5-year survival (both all-cause and liver related) compared with patients untreated for HCV. Patients eligible for HCC therapy should also be considered for DAA therapy.

Selfconsistent random phase approximation methods.

This Perspective reviews recent efforts toward selfconsistent calculations of ground-state energies within the random phase approximation (RPA) in the (generalized) Kohn-Sham (KS) density functional theory context. Since the RPA correlation energy explicitly depends on the non-interacting KS potential, an additional condition to determine the energy as a functional of the density is necessary. This observation leads to the concept of functional selfconsistency (FSC), which requires that the KS density equals the interacting density defined as the functional derivative of the ground-state energy with respect to the external potential. While all existing selfconsistent RPA schemes violate FSC, the recent generalized KS semicanonical projected RPA (GKS-spRPA) method takes a step toward satisfying it. This leads to systematic improvements in densities, binding energy curves, reference state stability, and molecular properties compared to non-selfconsistent RPA as well as optimized effective potential RPA. GKS-spRPA orbital energies accurately approximate valence and core ionization potentials, and even electron affinities of non-valence bound anions. The computational cost and performance of GKS-spRPA are compared to those of related selfconsistent schemes, including GW and orbital optimization methods, and limitations are discussed. Large differences between KS and interacting densities observed in the absence of FSC and the well-rounded performance of GKS-spRPA suggest that the KS potential as a density functional should be defined via the FSC condition for explicitly potential-dependent density functionals.

"Blepharophimosis-plus" syndromes: Frequency of systemic genetic disorders that also include blepharophimosis.

BACKGROUND: To determine the frequency of isolated blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) versus systemic genetic disorders in patients presenting with blepharophimosis. METHODS: Retrospective clinical records review. The records of all patients with blepharophimosis seen in the Division of Ophthalmology at the Children's Hospital of Philadelphia during a 12-year-period (2009-2020) were reviewed for medical history, clinical examination findings and results of genetic analyses. RESULTS: The 135 patients identified with blepharophimosis included 72 females (53%) and 63 males (47%) whose mean ± standard deviation age at first visit was 3.5 ± 6.4 years (range 0-39.8 years). Sixty-seven of the patients (50%) had undergone genetic testing for FOXL2 gene mutation. Fifty-four (81%) harboured FOXL2 gene mutations and 13 (19%) did not. Altogether, 126 patients (93%) had a final diagnosis of isolated BPES. The remaining nine (7%) had syndromic diagnoses ("blepharophimosis-plus"), including Dubowitz syndrome (n = 2), Ohdo syndrome (n = 1), 22q11.2 duplication (n = 1) and 3q22 deletion (n = 2). Three patients with multiple congenital anomalies remain undiagnosed. CONCLUSIONS: Blepharophimosis is an eyelid feature occurring most commonly in isolation due to FOXL2 gene mutation, but can also be a harbinger of multisystem disease not exclusive to isolated BPES, as observed in 7% of cases in this series. The ophthalmologist is often the first to recognise these unique features, and must consider and rule out non-BPES syndromes before establishing a diagnosed classic BPES. A comprehensive genetic evaluation is, therefore, indicated in all cases.

Residues in the fingers domain of the translesion DNA polymerase DinB enable its unique participation in error-prone double-strand break repair.

The evolutionarily conserved Escherichia coli translesion DNA polymerase IV (DinB) is one of three enzymes that can bypass potentially deadly DNA lesions on the template strand during DNA replication. Remarkably, however, DinB is the only known translesion DNA polymerase active in RecA-mediated strand exchange during error-prone double-strand break repair. In this process, a single-stranded DNA (ssDNA)-RecA nucleoprotein filament invades homologous dsDNA, pairing the ssDNA with the complementary strand in the dsDNA. When exchange reaches the 3' end of the ssDNA, a DNA polymerase can add nucleotides onto the end, using one strand of dsDNA as a template and displacing the other. It is unknown what makes DinB uniquely capable of participating in this reaction. To explore this topic, we performed molecular modeling of DinB's interactions with the RecA filament during strand exchange, identifying key contacts made with residues in the DinB fingers domain. These residues are highly conserved in DinB, but not in other translesion DNA polymerases. Using a novel FRET-based assay, we found that DinB variants with mutations in these conserved residues are less effective at stabilizing RecA-mediated strand exchange than native DinB. Furthermore, these variants are specifically deficient in strand displacement in the absence of RecA filament. We propose that the amino acid patch of highly conserved residues in DinB-like proteins provides a mechanistic explanation for DinB's function in strand exchange and improves our understanding of recombination by providing evidence that RecA plays a role in facilitating DinB's activity during strand exchange.

A Microfluidic Ion Sensor Array.

A balanced concentration of ions is essential for biological processes to occur. For example, [H+ ] gradients power adenosine triphosphate synthesis, dynamic changes in [K+ ] and [Na+ ] create action potentials in neuronal communication, and [Cl- ] contributes to maintaining appropriate cell membrane voltage. Sensing ionic concentration is thus important for monitoring and regulating many biological processes. This work demonstrates an ion-selective microelectrode array that simultaneously and independently senses [K+ ], [Na+ ], and [Cl- ] in electrolyte solutions. To obtain ion specificity, the required ion-selective membranes are patterned using microfluidics. As a proof of concept, the change in ionic concentration is monitored during cell proliferation in a cell culture medium. This microelectrode array can easily be integrated in lab-on-a-chip approaches to physiology and biological research and applications.