Longitudinal Fluctuations in Treatment Response After OnabotulinumToxinA and Sacral Neuromodulation for Refractory Urgency Incontinence.

PURPOSE: We compared fluctuations in treatment response after onabotulinumtoxinA and sacral neuromodulation for urgency incontinence using Markov models. MATERIALS AND METHODS: We fit data from a randomized trial to Markov models to compare transitions of success/failure over 6 months between 200 U onabotulinumtoxinA and sacral neuromodulation. Objective failure was <50% reduction in urgency incontinence episodes from baseline; subjective failure "strongly disagree" to "neutral" to the Patient Global Symptom Control questionnaire. RESULTS: Of the 357 participants (median baseline daily urgency incontinence episodes 4.7 [IQR 3.7-6.0]) 61% vs 51% and 3.2% vs 6.1% reported persistent states of objective success and failure over 6 months after onabotulinumtoxinA vs sacral neuromodulation. Participants receiving onabotulinumtoxinA vs sacral neuromodulation had lower 30-day transition probabilities from objective and subjective success to failure (10% vs 14%, ratio 0.75 [95% CI 0.55-0.95]; 14% vs 21%, ratio 0.70 [95% CI 0.51-0.89]). The 30-day transition probability from objective and subjective failure to success did not differ between onabotulinumtoxinA and sacral neuromodulation (40% vs 36%, ratio 1.11 [95% CI 0.73-1.50]; 18% vs 17%, ratio 1.14 [95% CI 0.65-1.64]). CONCLUSIONS: Over 6 months after treatment, 2 in 5 women's symptoms fluctuate. Within these initial 6 months, women receiving onabotulinumtoxinA transitioned from success to failure over 30 days less often than sacral neuromodulation. For both treatments, there was an almost 20%-40% probability over 30 days that women returned to subjective and objective success after failure. Markov models add important information to longitudinal models on how symptoms fluctuate after urgency incontinence treatment.

Predicting success using response after lead implantation with sacral neuromodulation for urgency incontinence.

IMPORTANCE: Many women report inadequate symptom control after sacral neuromodulation (SNM), despite 50% reduction in urgency incontinence episodes (UUIE) after test stimulation. OBJECTIVE: To determine the ideal percent UUIE reduction after test stimulation that predicts 24-month success. STUDY DESIGN: Using data from a multicenter SNM trial, we constructed receiver operating characteristic curves to identify an ideal threshold of percent UUIE reduction after test stimulation. We defined 24-month success as Patient Global Impression of Improvement of "very much better" to "better." We compared predictive accuracy of two models predicting success: (1) percent UUIE reduction alone and (2) with baseline characteristics. RESULTS: Of 149 women (median [IQR] baseline daily UUIE 4.7 [3.7, 6.0]), the ideal threshold for 24-month success was 72% (95% confidence interval 64,76%) UUIE reduction with accuracy 0.54 (0.42, 0.66), sensitivity 0.71 (0.56, 0.86) and specificity 0.27 (0.05, 0.55). The accuracy of the 50% reduction threshold was 0.60 (0.49, 0.71), sensitivity 0.95 (0.88, 1.0) and specificity 0.04 (0.0, 0.12). Percent reduction in UUIE was not better than chance in predicting 24-month success (concordance index [c-index] 0.47 [0.46, 0.62]); adding age, body mass index, diabetes mellitus and visual or hearing impairment the c-index was 0.68 (0.61, 0.78). CONCLUSIONS: Among women who received an internal pulse generator (IPG) due to ≥50% UUIE reduction after test stimulation, we found no ideal threshold that better predicted 24-month success. Percent reduction in UUIE after test stimulation poorly predicts 24-month success with or without clinical factors. Given this, re-evaluating how we determine who should receive an IPG is needed.

Primary amebic meningoencephalitis: a review of Naegleria fowleri and analysis of successfully treated cases.

Primary amebic meningoencephalitis (PAM) is a necrotizing and hemorrhagic inflammation of the brain and meninges caused by Naegleria fowleri, a free-living thermophilic ameba of freshwater systems. PAM remains a neglected disease that disproportionately affects children in tropical and subtropical climates, with an estimated mortality rate of 95-98%. Due to anthropogenic climate change, the average temperature in the USA has increased by 0.72 to 1.06 °C in the last century, promoting the poleward spread of N. fowleri. PAM is often misdiagnosed as bacterial meningitis or viral encephalitis, which shortens the window for potentially life-saving treatment. Diagnosis relies on the patient's history of freshwater exposure and the physician's high index of suspicion, supported by cerebrospinal fluid studies. While no experimental trials have been conducted to assess the relative efficacy of treatment regimens, anti-amebic therapy with adjunctive neuroprotection is standard treatment in the USA. We performed a literature review and identified five patients from North America between 1962 and 2022 who survived PAM with various degrees of sequelae.

Chemoproteomics Yields a Selective Molecular Host for Acetyl-CoA.

Chemoproteomic profiling is a powerful approach to define the selectivity of small molecules and endogenous metabolites with the human proteome. In addition to mechanistic studies, proteome specificity profiling also has the potential to identify new scaffolds for biomolecular sensing. Here, we report a chemoproteomics-inspired strategy for selective sensing of acetyl-CoA. First, we use chemoproteomic capture experiments to validate the N-terminal acetyltransferase NAA50 as a protein capable of differentiating acetyl-CoA and CoA. A Nanoluc-NAA50 fusion protein retains this specificity and can be used to generate a bioluminescence resonance energy transfer (BRET) signal in the presence of a CoA-linked fluorophore. This enables the development of a ligand displacement assay in which CoA metabolites are detected via their ability to bind the Nanoluc-NAA50 protein "host" and compete binding of the CoA-linked fluorophore "guest". We demonstrate that the specificity of ligand displacement reflects the molecular recognition of the NAA50 host, while the window of dynamic sensing can be controlled by tuning the binding affinity of the CoA-linked fluorophore guest. Finally, we show that the method's specificity for acetyl-CoA can be harnessed for gain-of-signal optical detection of enzyme activity and quantification of acetyl-CoA from cellular samples. Overall, our studies demonstrate the potential of harnessing insights from chemoproteomics for molecular sensing and provide a foundation for future applications in target engagement and selective metabolite detection.

Biochemical Analysis Leads to Improved Orthogonal Bioluminescent Tools.

Engineered luciferase-luciferin pairs have expanded the number of cellular targets that can be visualized in tandem. While light production relies on selective processing of synthetic luciferins by mutant luciferases, little is known about the origin of selectivity. The development of new and improved pairs requires a better understanding of the structure-function relationship of bioluminescent probes. In this work, we report a biochemical approach to assessing and optimizing two popular bioluminescent pairs: Cashew/d-luc and Pecan/4'-BrLuc. Single mutants derived from Cashew and Pecan revealed key residues for selectivity and thermal stability. Stability was further improved through a rational addition of beneficial residues. In addition to providing increased stability, the known stabilizing mutations surprisingly also improved selectivity. The resultant improved pair of luciferases are >100-fold selective for their respective substrates and highly thermally stable. Collectively, this work highlights the importance of mechanistic insight for improving bioluminescent pairs and provides significantly improved Cashew and Pecan enzymes which should be immediately suitable for multicomponent imaging applications.

Phenotyping of Urinary Urgency Patients Without Urgency Incontinence, and Their Comparison to Urgency Incontinence Patients: Findings From the LURN Study.

PURPOSE: We characterize patients with urinary urgency with vs without urgency urinary incontinence who presented to clinics actively seeking treatment for their symptoms. MATERIALS AND METHODS: Participants who enrolled in the Symptoms of Lower Urinary Tract Dysfunction Research Network were categorized into urinary urgency with vs without urgency urinary incontinence. Participants were followed for 1 year; their urinary symptoms, urological pain, psychosocial factors, bowel function, sleep disturbance, physical activity levels, physical function, and quality of life were compared. Mixed effects linear regression models were used to examine the relationships between urgency urinary incontinence and these factors. RESULTS: Among 683 participants with urinary urgency at baseline, two-thirds (n=453) also had urgency urinary incontinence; one-third (n=230) had urinary urgency-only without urgency urinary incontinence. No differences were detected in urological pain between urinary urgency-only and urgency urinary incontinence. Those with urgency urinary incontinence had more severe urgency and frequency symptoms, higher depression, anxiety, perceived stress scores, more severe bowel dysfunction and sleep disturbance, lower physical activity levels, lower physical function, and worse quality of life than those with urinary urgency-only. Among those with urinary urgency-only at baseline, 40% continued to have urinary urgency-only, 15% progressed to urgency urinary incontinence, and 45% had no urgency at 12 months. Fifty-eight percent with urgency urinary incontinence at baseline continued to report urgency urinary incontinence at 12 months, while 15% improved to urinary urgency-only, and 27% had no urgency. CONCLUSIONS: Patients with urgency urinary incontinence have severe storage symptoms, more psychosocial symptoms, poorer physical functioning, and worse quality of life. Our data suggested urgency urinary incontinence may be a more severe manifestation of urinary urgency, rather than urinary urgency and urgency urinary incontinence being distinct entities.

Cost-effectiveness of bacteriuria screening before urogynecologic surgery.

BACKGROUND: Currently, there is controversy over who requires preoperative screening for bacteriuria in the urogynecologic population and whether treating asymptomatic bacteriuria reduces postoperative urinary tract infection rates. OBJECTIVE: To evaluate the cost-effectiveness of selective, universal, and no preoperative bacteriuria screening protocols in women undergoing surgery for prolapse or stress urinary incontinence. STUDY DESIGN: A simple decision tree model was created from a societal perspective to evaluate cost and effectiveness of 3 strategies to prevent postoperative urinary tract infection: (1) a universal protocol where all women undergoing urogynecologic surgery are screened for bacteriuria and receive preemptive treatment if bacteriuria is identified; (2) a selective protocol, where only women with a history of recurrent urinary tract infection are screened and treated for bacteriuria; and (3) a no-screening protocol, where no women are screened for bacteriuria. Our primary outcome was the incremental cost-effectiveness ratio, calculated in cost per quality-adjusted life-years. Secondary outcomes were the number of urine cultures, postoperative urinary tract infections, and pyelonephritis associated with each strategy. Costs were derived from the Centers for Medicare & Medicaid Services, Healthcare Cost and Utilization Project, and Medical Expenditure Panel Survey. Clinical estimates were derived from published literature and data from a historic surgical cohort. Quality-of-life-associated utilities for urinary tract infection (0.73), pyelonephritis (0.66), and antibiotic use (0.964) were derived from the published literature using the HALex scale, reported directly by affected patients. One-way sensitivity analyses were performed over the range of reported values. RESULTS: In the base case scenario, selective screening is more costly (no screen: $101.69, selective: $101.98) and more effective (no screen: 0.096459 quality-adjusted-life-year, selective: 0.096464 quality-adjusted-life-year) than no screening, and is cost-effective, with an incremental cost-effectiveness ratio of $49,349 per quality-adjusted-life-year. Both selective screening and no screening dominate universal screening in being less costly (universal: $111.92) and more effective (universal: 0.096446 quality-adjusted-life-year), with a slightly higher rate of postoperative urinary tract infection (no screen: 17.1%, selective: 16.9%, universal: 16.6%). In 1-way sensitivity analyses, selective screening is no longer cost-effective compared with no screening when the cost of a urine culture exceeds $12, cost of a preoperative urinary tract infection exceeds $93, the cost of a postoperative urinary tract infection is below $339, the specificity of a urine culture is less than 96%, or preoperative bacteriuria rates in those without symptoms but a history of recurrent urinary tract infection is <23%. Universal screening only becomes cost-effective when the postoperative urinary tract infection rate increases to >50% in those without risk factors and untreated preoperative bacteriuria. When compared with no screening, selective screening costs an additional $104 per urinary tract infection avoided and $2607 per pyelonephritis avoided. Compared with selective screening, universal screening costs $4609 per urinary tract infection avoided and $115,223 per pyelonephritis avoided. CONCLUSION: Implementation of a selective preoperative bacteriuria protocol is cost-effective in most scenarios and associated with only a <1% increase in the 30-day postoperative urinary tract infection rate. No screening is cost-effective when cost of a preoperative urinary tract infection is high and the rate of preoperative bacteriuria in those without risk factors is low.

Natural history of lower urinary tract symptoms in treatment-seeking women with pelvic organ prolapse; the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN).

BACKGROUND: The association of pelvic organ prolapse with overactive bladder and other lower urinary tract symptoms, and the natural history of those symptoms are not well characterized. Previous cross-sectional studies demonstrated conflicting relationships between prolapse and lower urinary tract symptoms. OBJECTIVE: This study primarily aimed to determine the baseline association between lower urinary tract symptoms and prolapse and to assess longitudinal differences in symptoms over 12 months in women with and without prolapse. Secondary aims were to explore associations between lower urinary tract symptoms and prolapse treatment. We hypothesized that: (1) prolapse is associated with the presence of lower urinary tract symptoms, (2) lower urinary tract symptoms are stable over time in patients with and without prolapse, and (3) prolapse treatment is associated with lower urinary tract symptom improvement. STUDY DESIGN: Women enrolled in the Symptoms of Lower Urinary Tract Dysfunction Research Network Observational Cohort Study with adequate 12-month follow-up data were included. Prolapse and lower urinary tract symptom treatment during follow-up was guided by standard of care. Outcome measures included the Lower Urinary Tract Symptoms Tool total severity score (in addition to overactive bladder, obstructive, and stress urinary incontinence subscales) and Urogenital Distress Inventory-6 Short Form. Prolapse (yes or no) was defined primarily when Pelvic Organ Prolapse Quantification System points Ba, C or Bp were >0 (beyond the hymen). Mixed-effects models with random effects for patient slopes and intercepts were fitted for each lower urinary tract symptom outcome and prolapse predictor, adjusted for other covariates. The study had >90% power to detect differences as small as 0.4 standard deviation for less prevalent group comparisons (eg, prolapse vs not). RESULTS: A total of 371 women were analyzed, including 313 (84%) with no prolapse and 58 (16%) with prolapse. Women with prolapse were older (64.6±8.8 vs 55.3±14.1 years; P<.001) and more likely to have prolapse surgery (28% vs 1%; P<.001) and pessary treatment (26% vs 4%; P<.001) during the study. Average baseline Lower Urinary Tract Symptoms Tool total severity scores were lower (fewer symptoms) for participants with prolapse compared with those without (38.9±14.0 vs 43.2±14.0; P=.036), but there were no differences in average scores between prolapse groups for other scales. For all urinary outcomes, average scores were significantly lower (improved) at 3 and 12 months compared with baseline (all P<.05). In mixed-effects models, there were no statistically significant interactions between pelvic organ prolapse measurement and visit and time-dependent prolapse treatment groups (P>.05 for all regression interaction coefficients). The Lower Urinary Tract Symptoms Tool obstructive severity score had a statistically significant positive association with Pelvic Organ Prolapse Quantification System Ba, Bp, and point of maximum vaginal descent. The Lower Urinary Tract Symptoms Tool total severity scale had a statistically significant negative association with Pelvic Organ Prolapse Quantification System Ba and point of maximum vaginal descent. No other associations between prolapse and lower urinary tract symptoms were significant (P>.05 for all regression coefficients). Symptom differences between prolapse groups were small: all regression coefficients (interpretable as additive percentage change in each score) were between -5 and 5 (standard deviation of outcomes ranged from 14.0-32.4). CONCLUSION: Among treatment-seeking women with urinary symptoms, obstructive symptoms were positively associated with prolapse, and overall lower urinary tract symptom severity was negatively associated with prolapse. Lower Urinary Tract Symptoms Tool scores improved over 12 months regardless of prolapse status, including in those with treated prolapse, untreated prolapse, and without prolapse.

Predicting outcomes after intradetrusor onabotulinumtoxina for non-neurogenic urgency incontinence in women.

AIMS: Develop models to predict outcomes after intradetrusor injection of 100 or 200 units of onabotulinumtoxinA in women with non-neurogenic urgency urinary incontinence (UUI). METHODS: Models were developed using 307 women from two randomized trials assessing efficacy of onabotulinumtoxinA for non-neurogenic UUI. Cox, linear and logistic regression models were fit using: (1) time to recurrence over 12 months, (2) change from baseline daily UUI episodes (UUIE) at 6 months, and (3) need for self-catheterization over 6 months. Model discrimination of Cox and logistic regression models was calculated using c-index. Mean absolute error determined accuracy of the linear model. Calibration was demonstrated using calibration curves. All models were internally validated using bootstrapping. RESULTS: Median time to recurrence was 6 (interquartile range [IQR]: 2-12) months. Increasing age, 200 units of onabotulinumtoxinA, higher body mass index (BMI) and baseline UUIE were associated with decreased time to recurrence. The c-index was 0.63 (95% confidence interval [CI]: 0.59, 0.67). Median change in daily UUIE from baseline at 6 months was -3.5 (IQR: -5.0, -2.3). Increasing age, lower baseline UUIE, 200 units of onabotulinumtoxinA, higher BMI and IIQ-SF were associated with less improvement in UUIE. The mean absolute error predicting change in UUIE was accurate to 1.6 (95% CI: 1.5, 1.7) UUI episodes. The overall rate of self-catheterization was 17.6% (95% CI: 13.6%-22.4%). Lower BMI, 200 units of onabotulinumtoxinA, increased baseline postvoid residual and maximum capacity were associated with higher risk of self-catheterization. The c-index was 0.66 (95% CI: 0.61, 0.76). The three calculators are available at http://riskcalc.duke.edu. CONCLUSIONS: After external validation, these models will assist clinicians in providing more accurate estimates of expected treatment outcomes after onabotulinumtoxinA for non-neurogenic UUI in women.

Cost-effectiveness of behavioral and pelvic floor muscle therapy combined with midurethral sling surgery vs surgery alone among women with mixed urinary incontinence: results of the Effects of Surgical Treatment Enhanced With Exercise for Mixed Urinary Incontinence randomized trial.

BACKGROUND: Urinary incontinence is prevalent among women, and it has a substantial economic impact. Mixed urinary incontinence, with both stress and urgency urinary incontinence symptoms, has a greater adverse impact on quality of life and is more complex to treat than either stress or urgency urinary incontinence alone. Studies evaluating the cost-effectiveness of treating both the stress and urgency urinary incontinence components simultaneously are lacking. OBJECTIVE: Cost-effectiveness was assessed between perioperative behavioral and pelvic floor muscle therapies combined with midurethral sling surgery and midurethral sling surgery alone for the treatment of women with mixed urinary incontinence. The impact of baseline severe urgency urinary incontinence symptoms on cost-effectiveness was assessed. STUDY DESIGN: This prospective economic evaluation was performed concurrently with the Effects of Surgical Treatment Enhanced with Exercise for Mixed Urinary Incontinence randomized trial that was conducted from October 2013 to April 2016. Participants included 480 women with moderate-to-severe stress and urgency urinary incontinence symptoms and at least 1 stress urinary incontinence episode and 1 urgency urinary incontinence episode on a 3-day bladder diary. The primary within-trial analysis was from the healthcare sector and societal perspectives, with a 1-year time horizon. Costs were in 2019 US dollars. Effectiveness was measured in quality-adjusted life-years and reductions in urinary incontinence episodes per day. Incremental cost-effectiveness ratios of combined treatment vs midurethral sling surgery alone were calculated, and cost-effectiveness acceptability curves were generated. Analysis was performed for the overall study population and subgroup of women with Urogenital Distress Inventory irritative scores of ≥50th percentile. RESULTS: The costs for combined treatment were higher than the cost for midurethral sling surgery alone from both the healthcare sector perspective ($5100 [95% confidence interval, $5000-$5190] vs $4470 [95% confidence interval, $4330-$4620]; P<.01) and the societal perspective ($9260 [95% confidence interval, $8590-$9940] vs $8090 [95% confidence interval, $7630-$8560]; P<.01). There was no difference between combined treatment and midurethral sling surgery alone in quality-adjusted life-years (0.87 [95% confidence interval, 0.86-0.89] vs 0.87 [95% confidence interval, 0.86-0.89]; P=.90) or mean reduction in urinary incontinence episodes per day (-4.76 [95% confidence interval, -4.51 to 5.00] vs -4.50 [95% confidence interval, -4.25 to 4.75]; P=.13). When evaluating the overall study population, from both the healthcare sector and societal perspectives, midurethral sling surgery alone was superior to combined treatment. The probability that combined treatment is cost-effective compared with midurethral sling surgery alone is ≤28% from the healthcare sector and ≤19% from the societal perspectives for a willingness-to-pay value of ≤$150,000 per quality-adjusted life-years. For women with baseline Urogenital Distress Inventory irritative scores of ≥50th percentile, combined treatment was cost-effective compared with midurethral sling surgery alone from both the healthcare sector and societal perspectives. The probability that combined treatment is cost-effective compared with midurethral sling surgery alone for this subgroup is ≥90% from both the healthcare sector and societal perspectives, at a willingness-to-pay value of ≥$150,000 per quality-adjusted life-years. CONCLUSION: Overall, perioperative behavioral and pelvic floor muscle therapies combined with midurethral sling surgery was not cost-effective compared with midurethral sling surgery alone for the treatment of women with mixed urinary incontinence. However, combined treatment was of good value compared with midurethral sling surgery alone for women with baseline severe urgency urinary incontinence symptoms.

Sacral neuromodulation: troubleshooting needle placement.

INTRODUCTION AND HYPOTHESIS: The objective was to develop an instructional video that utilizes fluoroscopic images and anatomical landmarks to increase the surgeon's ability to troubleshoot optimal placement of the foramen needle and lead during a stage I sacral neuromodulation (SNM) procedure. METHODS: Eight different examples of suboptimal foramen needle placement with subsequent corrections during a SNM procedure were performed and recorded on a fresh female cadaver. RESULTS: Fluoroscopic images were obtained during the procedure, and illustrations of the posterior aspect of the sacrum highlighting the S3 foramina and nerve are shown for anatomical comparison. CONCLUSIONS: This video demonstrates how to efficiently identify and correct suboptimal foramen needle placement in order to obtain optimal lead placement during an SNM procedure. Understanding the relationship between the bony landmarks on fluoroscopy and the S3 nerve and foramen are important in order to understand how to correct a suboptimal foramen needle and thus achieve optimal lead placement.

Sacral neuromodulation: sacral anatomy and optimal lead placement.

INTRODUCTION AND HYPOSTHESIS: To develop an instructional video that correlates cadaveric anatomy with fluoroscopic images to assist in conceptualization of optimal placement of the foramen needle and lead to complete an efficient and successful sacral neuromodulation (SNM) procedure. METHODS: A SNM procedure was performed and recorded on a fresh female cadaver. Fluoroscopic images were obtained during the procedure to highlight the bony relationships to the S3 foramen and nerve. Dissection of the anterior and posterior sacrum was completed to highlight the tract of the S3 nerve. Techniques to increase the likelihood of optimal foramen needle and thus lead placement were highlighted. CONCLUSIONS: This video demonstrates how achieving optimal foramen needle placement within the S3 foramen is key to optimal lead placement. Understanding the relationship of the bony landmarks on fluoroscopy to the S3 nerve and foramen, seen in the cadaveric dissections, are important in understanding how to achieve optimal lead placement. This optimization should lead to decreased operating room time, maximization of programming options, and decreased amplitude requirements.

Educating outdoor workers using tailored and financial messages to encourage safe-sun behaviors.

Excessive and unsafe sun exposure represents a concerning hazard to the health of individuals. Of particular interest are those who are most susceptible to sun exposure, such as outdoor workers. The current study used a 3 × 2 between-subjects design to investigate the effectiveness of messages that varied the extent of personalization (i.e. generic message; occupation targeted message; individual tailored message) and the inclusion of content regarding financial consequences of skin cancer. Participants (N = 304) were recruited from the USA through Amazon's Mechanical Turk and randomly assigned to view a generic message, occupation targeted message, or individual tailored message. Additionally, participants were randomly assigned to view messages in which financial information was either present or not. Participants responded to questions assessing pre- and post-test sun protection behaviors. Individual tailored messaging was as effective as occupation targeted messaging, with both being more effective than generic messaging. This finding indicates that some degree of personalization is necessary when promoting safe-sun practices to outdoor workers, but that tailoring to individuals may not always be necessary. Inclusion of financial content in messaging resulted in greater intentions to practice sun protection behaviors. Results provide insight into effective methods for promoting sun protection.

Polyploid Hepatocytes Facilitate Adaptation and Regeneration to Chronic Liver Injury.

The liver contains diploid and polyploid hepatocytes (tetraploid, octaploid, etc.), with polyploids comprising ≥90% of the hepatocyte population in adult mice. Polyploid hepatocytes form multipolar spindles in mitosis, which lead to chromosome gains/losses and random aneuploidy. The effect of aneuploidy on liver function is unclear, and the degree of liver aneuploidy is debated, with reports showing aneuploidy affects 5% to 60% of hepatocytes. To study relationships among liver polyploidy, aneuploidy, and adaptation, mice lacking E2f7 and E2f8 in the liver (LKO), which have a polyploidization defect, were used. Polyploids were reduced fourfold in LKO livers, and LKO hepatocytes remained predominantly diploid after extensive proliferation. Moreover, nearly all LKO hepatocytes were euploid compared with control hepatocytes, suggesting polyploid hepatocytes are required for production of aneuploid progeny. To determine whether reduced polyploidy impairs adaptation, LKO mice were bred onto a tyrosinemia background, a disease model whereby the liver can develop disease-resistant, regenerative nodules. Although tyrosinemic LKO mice were more susceptible to morbidities and death associated with tyrosinemia-induced liver failure, they developed regenerating nodules similar to control mice. Analyses revealed that nodules in the tyrosinemic livers were generated by aneuploidy and inactivating mutations. In summary, we identified new roles for polyploid hepatocytes and demonstrated that they are required for the formation of aneuploid progeny and can facilitate adaptation to chronic liver disease.

The Polyploid State Restricts Hepatocyte Proliferation and Liver Regeneration in Mice.

The liver contains a mixture of hepatocytes with diploid or polyploid (tetraploid, octaploid, etc.) nuclear content. Polyploid hepatocytes are commonly found in adult mammals, representing ~90% of the entire hepatic pool in rodents. The cellular and molecular mechanisms that regulate polyploidization have been well characterized; however, it is unclear whether diploid and polyploid hepatocytes function similarly in multiple contexts. Answering this question has been challenging because proliferating hepatocytes can increase or decrease ploidy, and animal models with healthy diploid-only livers have not been available. Mice lacking E2f7 and E2f8 in the liver (liver-specific E2f7/E2f8 knockout; LKO) were recently reported to have a polyploidization defect, but were otherwise healthy. Herein, livers from LKO mice were rigorously characterized, demonstrating a 20-fold increase in diploid hepatocytes and maintenance of the diploid state even after extensive proliferation. Livers from LKO mice maintained normal function, but became highly tumorigenic when challenged with tumor-promoting stimuli, suggesting that tumors in LKO mice were driven, at least in part, by diploid hepatocytes capable of rapid proliferation. Indeed, hepatocytes from LKO mice proliferate faster and out-compete control hepatocytes, especially in competitive repopulation studies. In addition, diploid or polyploid hepatocytes from wild-type (WT) mice were examined to eliminate potentially confounding effects associated with E2f7/E2f8 deficiency. WT diploid cells also showed a proliferative advantage, entering and progressing through the cell cycle faster than polyploid cells, both in vitro and during liver regeneration (LR). Diploid and polyploid hepatocytes responded similarly to hepatic mitogens, indicating that proliferation kinetics are unrelated to differential response to growth stimuli. Conclusion: Diploid hepatocytes proliferate faster than polyploids, suggesting that the polyploid state functions as a growth suppressor to restrict proliferation by the majority of hepatocytes.

Making Glove Decision Less of a White Knuckling Experience: A Systematic Review and Inventory of Glove Accelerator Contents.

BACKGROUND: Accelerators in medical gloves are a common cause of allergic contact dermatitis among healthcare workers. OBJECTIVE: A systematic review of medical and nursing literature, patch testing reports, and chemical analyses of gloves was conducted to assess accelerator contents reported in the literature and to identify accelerator-free gloves. METHODS: A systematic literature search was performed in OVID Medline and OVID EMBASE. Hand-searching of reference lists of articles in the field and author input generated the remainder of articles assessed. RESULTS: We present an inventory of accelerator contents of gloves and accelerator-free glove options as reported in the literature as a clinical reference tool to assist allergen-free glove selection for individuals suffering from allergic contact dermatitis due to rubber accelerators. LIMITATIONS: Pertinent limitations of our review include lack of predefined study exclusion criteria and screening of the studies identified in the search by 1 review author only. CONCLUSION: The glove inventory we provide summarizes the available literature regarding medical and surgical glove accelerator content, describing gloves both by brand and manufacturer as well as by accelerators.

A dynamic loop provides dual control over the catalytic and membrane binding activity of a bacterial serine hydrolase.

The bacterial acyl protein thioesterase (APT) homologue FTT258 from the gram-negative pathogen Francisella tularensis exists in equilibrium between a closed and open state. Interconversion between these two states is dependent on structural rearrangement of a dynamic loop overlapping its active site. The dynamics and structural properties of this loop provide a simple model for how the catalytic activity of FTT258 could be spatiotemporally regulated within the cell. Herein, we characterized the dual roles of this dynamic loop in controlling its catalytic and membrane binding activity. Using a comprehensive library of loop variants, we determined the relative importance of each residue in the loop to these two biological functions. For the catalytic activity, a centrally located tryptophan residue (Trp66) was essential, with the resulting alanine variant showing complete ablation of enzyme activity. Detailed analysis of Trp66 showed that its hydrophobicity in combination with spatial arrangement defined its essential role in catalysis. Substitution of other loop residues congregated along the N-terminal side of the loop also significantly impacted catalytic activity, indicating a critical role for this loop in controlling catalytic activity. For membrane binding, the centrally located hydrophobic residues played a surprising minor role in membrane binding. Instead general electrostatic interactions regulated membrane binding with positively charged residues bracketing the dynamic loop controlling membrane binding. Overall for FTT258, this dynamic loop dually controlled its biological activities through distinct residues within the loop and this regulation provides a new model for the spatiotemporal control over FTT258 and potentially homologous APT function.