Development of Sensory, Motor and Behavioral Deficits in the Murine Model of Sanfilippo Syndrome Type B

BACKGROUND: Mucopolysaccharidosis (MPS) IIIB (Sanfilippo Syndrome type B) is caused by a deficiency in the lysosomal enzyme N-acetyl-glucosaminidase (Naglu). Children with MPS IIIB develop disturbances of sleep, activity levels, coordination, vision, hearing, and mental functioning culminating in early death. The murine model of MPS IIIB demonstrates lysosomal distention in multiple tissues, a shortened life span, and behavioral changes. PRINCIPAL FINDINGS: To more thoroughly assess MPS IIIB in mice, alterations in circadian rhythm, activity level, motor function, vision, and hearing were tested. The suprachiasmatic nucleus (SCN) developed pathologic changes and locomotor analysis showed that MPS IIIB mice start their daily activity later and have a lower proportion of activity during the night than wild-type controls. Rotarod assessment of motor function revealed a progressive inability to coordinate movement in a rocking paradigm. Purkinje cell counts were significantly reduced in the MPS IIIB animals compared to age matched controls. By electroretinography (ERG), MPS IIIB mice had a progressive decrease in the amplitude of the dark-adapted b-wave response. Corresponding pathology revealed shortening of the outer segments, thinning of the outer nuclear layer, and inclusions in the retinal pigmented epithelium. Auditory-evoked brainstem responses (ABR) demonstrated progressive hearing deficits consistent with the observed loss of hair cells in the inner ear and histologic abnormalities in the middle ear. CONCLUSIONS/SIGNIFICANCE: The mouse model of MPS IIIB has several quantifiable phenotypic alterations and is similar to the human disease. These physiologic and histologic changes provide insights into the progression of this disease and will serve as important parameters when evaluating various therapies

Mucopolysaccharidosis type IIIB: a current review and exploration of the AAV therapy landscape

Mucopolysaccharidoses type IIIB is a rare genetic disorder caused by mutations in the gene that encodes for N-acetyl-alpha-glucosaminidase. This results in the aggregation of heparan sulfate polysaccharides within cell lysosomes that leads to progressive and severe debilitating neurological dysfunction. Current treatment options are expensive, limited, and presently there are no approved cures for mucopolysaccharidoses type IIIB. Adeno-associated virus gene therapy has significantly advanced the field forward, allowing researchers to successfully design, enhance, and improve potential cures. Our group recently published an effective treatment using a codon-optimized triple mutant adeno-associated virus 8 vector that restores N-acetyl-alpha-glucosaminidase levels, auditory function, and lifespan in the murine model for mucopolysaccharidoses type IIIB to that seen in healthy mice. Here, we review the current state of the field in relation to the capsid landscape, adeno-associated virus gene therapy and its successes and challenges in the clinic, and how novel adeno-associated virus capsid designs have evolved research in the mucopolysaccharidoses type IIIB field

Projected clinical benefit of surveillance imaging for early detection and treatment of breast cancer metastases

This article presents current best knowledge to assess the projected outcomes benefit of adding multi‐modality surveillance imaging to standard follow‐up care for breast cancer patients at high risk (>30%) for developing future metastases. This analysis is motivated by recent preliminary clinical studies that have suggested that augmenting systemic treatment of early‐stage metastases with targeted surgery and/or radiosurgery achieves significant overall survival and disease‐free survival benefit. Our primary aims are to: (a) describe the clinical motivation and scan parameters needed to identify the early onset of metastatic progression in breast cancer patients for effective surgical or radiosurgical treatment; (b) estimate the anticipated survival benefit for high‐risk patients under this recommended protocol; and (c) estimate the radiation risks associated with the repeated body imaging of this protocol

Differential expression and function of CAIX and CAXII in breast cancer: A comparison between tumorgraft models and cells.

Carbonic anhydrase IX (CAIX) and XII (CAXII) are transmembrane proteins that are associated with cancer progression. We have previously described the catalytic properties of CAIX in MDA-MB-231 breast cancer cells, a line of cells that were derived from a patient with triple negative breast cancer. We chose this line because CAIX expression in breast cancer is a marker of hypoxia and a prognosticator for reduced survival. However, CAXII expression is associated with better survival statistics than those patients with low CAXII expression. Yet CAIX and CAXII have similar catalytic activities. Here we compare the potential roles of CAIX and CAXII in the context of TNBC and estrogen receptor (ER)-positive breast cancer. In tumor graft models, we show that CAIX and CAXII exhibit distinct expression patterns and non-overlapping. We find the same pattern across a panel of TNBC and luminal breast cancer cell lines. This affords an opportunity to compare directly CAIX and CAXII function. Our data suggest that CAIX expression is associated with growth potentiation in the tumor graft model and in a TNBC line using knockdown strategies and blocking activity with an impermeant sulfonamide inhibitor, N-3500. CAXII was not associated with growth potentiation. The catalytic activities of both CAIX and CAXII were sensitive to inhibition by N-3500 and activated at low pH. However, pH titration of activity in membrane ghosts revealed significant differences in the catalytic efficiency and pKa values. These features provide evidence that CAIX is a more efficient enzyme than CAXII at low pH and that CAIX shifts the equilibrium between CO2 and bicarbonate in favor of CO2 production by consuming protons. This suggests that in the acidic microenvironment of tumors, CAIX plays a role in stabilizing pH at a value that favors cancer cell survival

A Pilot Study on Burnout in Medical Students (BuMS) over an Academic Year

Background: Physician burnout is increasingly recognized as a problem in physician well-being and may negatively affect patient care outcomes. Burnout can begin at any point of training or practice, potentially as early as the first year of medical school. Thus, there is a need to characterize possible burnout in medical students as the first step to optimizing strategies for mitigation. Traditionally, burnout has been studied using survey-based variables; however, identifying novel physiological and molecular biomarkers could allow for the expansion of screening and intervention strategies. Methods: In this pilot prospective cohort study, we followed a group of preclinical 1st and 2nd year medical students (n = 9) at the University of Florida over one academic year of medical school. We collected survey responses (Maslach Burnout Inventory [MBI], Patient Health Questionnaire-9 [PHQ-9], and Perceived Stress Scale [PSS]) and measured a panel of candidate physiological biomarkers of burnout (Inflammatory Cytokine Panel, Heart Rate Variability [HRV], and Leukocyte Telomere Length). Results: In the study participants, MBI composite scores and PHQ-9 scores showed a statistically significant increase over the course of an academic year, indicating higher levels of medical student burnout. Additionally, respondents reported a statistically significant decrease in time devoted to exercise, and we measured a significant increase in body mass index (BMI) during the academic year. PSS scores showed an upward trend which was not statistically significant. Likewise, average leukocyte telomere length trended downward, but the change was not statistically significant. There were no measured changes in the serum concentration of pro-inflammatory cytokines, and time-domain heart rate variability metrics did not differ significantly between timepoints. Conclusions: This pilot study supports the notion that burnout can begin early in medical school and is detectable via survey instruments in first-year and second-year medical students even with a small sample size. Additionally, leukocyte telomere length could potentially be a useful biomarker of burnout with supporting data, but we did not observe any statistically significant changes in inflammatory cytokines or heart rate variability. Further investigation into these potential biomarkers with larger cohort sizes is required to fully characterize their clinical utility

Epidemiological, Clinical, and Histopathological Features of Breast Cancer in Haiti

Purpose: Little is known about the epidemiology of breast cancer in developing countries, and Haiti has perhaps the least data of any country in the Western Hemisphere. Methods: We conducted a retrospective review of all patients enrolled in an ongoing breast cancer treatment program in Port-au-Prince, Haiti, from July 1, 2013, through June 30, 2017. Data were drawn from each patient's electronic medical record, paper chart, and biopsy results. Results: The records of 525 women with breast cancer were reviewed for this study. The median age at presentation was 49 years (n = 507). The risk factors observed were as follows: postmenopausal, 50.8% (n = 354); nulliparity, 15.7% (n = 338); hormonal contraception use, 35.0% (n = 309); never breastfed, 20.6% (n = 316); family history of any cancer, 22.0% (n = 295); overweight, 51.5% (n = 332); and smoking, 5.0% (n = 338). Of all those staged, 83.9% (n = 447) of the patients presented with stage III/IV disease and more than half delayed care for > 12 months after first noticing a breast mass. For the subset of tumors for which estrogen receptor (ER; n = 245) and human epidermal growth factor receptor 2 (HER2; n = 179) status was available, the prevalence of ER-positive tumors was 51.8%, of HER2-positive tumors was 19.6%, and of triple-negative tumors was 38.5%. The 12-month mortality rate (n = 425) was 18.4% overall and 27.5% for those who presented with stage IV disease. Median survival was not reached. Conclusion: Breast cancer in Haiti presents at an early age and advanced stage. Triple-negative, ER-negative, and high-grade tumors are common. Delays in seeking care and incomplete treatment likely contribute to the high mortality rate; however, as in black women in the United States, the distribution of tumor types may contribute to disparate outcomes