Diversity, Equity, and Inclusion in US Anesthesiology Residency Matching.

BACKGROUND: Patient outcomes are improved with physician-patient gender, racial, and ethnic concordance. However, female, Black, Hispanic or Latino, Native Hawaiian-Pacific Islander (NH-PI), and American Indian-Native Alaskan (AI-AN) physicians are underrepresented in anesthesiology. The American Association of Medical Colleges 2018 Diversity in Medicine Report revealed that women comprise only 35% of anesthesiologists yet nearly half of medical school graduates are women. More than 77% of anesthesiologists are White or Asian. Anesthesiology applicant and match trends may provide insights needed to address underrepresentation within anesthesiology. We hypothesized that proportionally fewer women and racially and ethnically minoritized applicants apply and match into anesthesiology. METHODS: This retrospective observational study identified 47,117 anesthesiology applicants among the 546,298 residency applicants in the Electronic Residency Application Service (ERAS) system between 2011 and 2022 and stratified applicants by self-reported gender, race, and ethnicity. The demographics of anesthesiology trainees reported in the 2014 to 2015, 2018 to 2019, and 2022 to 2023 Accreditation Counsel of Graduate Medical Education (ACGME) Data Resource Books were used as surrogates for matched applicants as demographics are not reported by the National Residency Match Program. To facilitate comparisons, ERAS applicants were grouped into 4-year epochs to align with consolidated ACGME reports corresponding to the application years. Odds ratios (OR); 95% confidence interval of applying to and matching into anesthesiology were analyzed. RESULTS: Women had lower odds of applying to anesthesiology compared to men overall (OR, 0.55; 95% CI, 0.54-0.56, P < .0001) and maintained significantly lowered odds of applying within each epoch. Women had similar odds of matching into anesthesiology residency compared to men (OR, 1.10; 95% CI, 1.06-1.14, P < .0001). Black, Hispanic or Latino, Asian and NH-PI, and AI-AN applicants had similar odds to White applicants of applying to anesthesiology but odds of matching were significantly lower overall (P < .0001) for Asian and NH-PI (OR, 0.66; 95% CI, 0.63-0.70), Black (OR, 0.49; 95% CI, 0.45-0.53), Hispanic or Latino (OR, 0.50; 95% CI, 0.46-0.54), and AI-AN (OR, 0.20; 95% CI, 0.15-0.28) applicants. The odds of matching among some minoritized applicants increased in the ACGME 2022 to 2023 report year. CONCLUSIONS: From 2011 to 2022, women had lower odds of applying to anesthesiology residency than men yet had similar odds of matching. Racial and ethnic minoritized groups had significantly lower odds of matching compared to White applicants despite similar odds of applying. These findings highlight disparities in the anesthesiology match and may help identify opportunities to promote workforce diversity within the field. More detailed reporting of gender, race, and ethnicity in annual match data may better define barriers to entry and identify opportunities for improvement.

Core Hippo pathway components act as a brake on Yap and Taz in the development and maintenance of the biliary network.

The development of the biliary system is a complex yet poorly understood process, with relevance to multiple diseases, including biliary atresia, choledochal cysts and gallbladder agenesis. We present here a crucial role for Hippo-Yap/Taz signaling in this context. Analysis of sav1 mutant zebrafish revealed dysplastic morphology and expansion of both intrahepatic and extrahepatic biliary cells, and ultimately larval lethality. Biliary dysgenesis, but not larval lethality, is driven primarily by Yap signaling. Re-expression of Sav1 protein in sav1-/- hepatocytes is able to overcome these initial deficits and allows sav1-/- fish to survive, suggesting cell non-autonomous signaling from hepatocytes. Examination of sav1-/- rescued adults reveals loss of gallbladder and formation of dysplastic cell masses expressing biliary markers, suggesting roles for Hippo signaling in extrahepatic biliary carcinomas. Deletion of stk3 revealed that the phenotypes observed in sav1 mutant fish function primarily through canonical Hippo signaling and supports a role for phosphatase PP2A, but also suggests Sav1 has functions in addition to facilitating Stk3 activity. Overall, this study defines a role for Hippo-Yap signaling in the maintenance of both intra- and extrahepatic biliary ducts.

Llgl1 regulates zebrafish cardiac development by mediating Yap stability in cardiomyocytes.

The Hippo-Yap pathway regulates multiple cellular processes in response to mechanical and other stimuli. In Drosophila, the polarity protein Lethal (2) giant larvae [L(2)gl], negatively regulates Hippo-mediated transcriptional output. However, in vertebrates, little is known about its homolog Llgl1. Here, we define a novel role for vertebrate Llgl1 in regulating Yap stability in cardiomyocytes, which impacts heart development. In contrast to the role of Drosophila L(2)gl, Llgl1 depletion in cultured rat cardiomyocytes decreased Yap protein levels and blunted target gene transcription without affecting Yap transcript abundance. Llgl1 depletion in zebrafish resulted in larger and dysmorphic cardiomyocytes, pericardial effusion, impaired blood flow and aberrant valvulogenesis. Cardiomyocyte Yap protein levels were decreased in llgl1 morphants, whereas Notch, which is regulated by hemodynamic forces and participates in valvulogenesis, was more broadly activated. Consistent with the role of Llgl1 in regulating Yap stability, cardiomyocyte-specific overexpression of Yap in Llgl1-depleted embryos ameliorated pericardial effusion and restored blood flow velocity. Altogether, our data reveal that vertebrate Llgl1 is crucial for Yap stability in cardiomyocytes and its absence impairs cardiac development.

Recent Trends in the Effect of Race and Gender on the Orthopedics Match.

Introduction Orthopedics has a reputation for being competitive but not diverse. Leaders of the orthopedics community have been making efforts to increase the participation of women and minorities in the field by raising awareness and strengthening pipeline programs. We aim to explore the trends in the risk of not matching by comparing the proportions of women and underrepresented populations in the applicant pools versus proportions in residency programs. Simultaneously, we aim to evaluate if women or underrepresented population applicants exhibit a lower likelihood of applying to orthopedics compared to male and White applicants. Methods The study received an IRB exemption. The authors collected Accreditation Council for Graduate Medical Education (ACGME) data books for the years 2015-2016 to 2022-2023 to obtain demographic information on orthopedic residents in training during each of those academic years. The pool of corresponding applicants (for example: residents in training during the 2021-2022 academic year would consist of five classes, made up of applicants from 2016-2017 to 2020-2021) was then tabulated from Electronic Residency Applications Service (ERAS) statistics, which are publicly available on the Association of American Medical Colleges (AAMC) website. The race and gender composition of the applicant pool was compared to that of corresponding enrolled residents to calculate the relative risk (RR) of women not matching compared to men and underrepresented population applicants (Blacks, Hispanics, Asians, and Native Americans) compared to White applicants. ERAS data was subsequently used to calculate the percentages of each demographic applying to all residency programs and orthopedic programs. Results For female applicants into orthopedic residency, they had a similar RR of going unmatched when compared to their male counterparts. In the academic year 2020-2021, there was an exception to this as women had a slightly higher RR of going unmatched. All underrepresented populations had a higher risk of not matching compared to White applicants for all cycles, peaking for residents in training in 2020-2021. The trendline improved for residents in the following year. Throughout the study, women accounted for 46.61% of applicants applying for any residency; however, they only accounted for 16.98% of applicants applying for orthopedic residency. A similar discrepancy is noted among Asian applicants but not Black or Hispanic applicants. Conclusions Underrepresented populations were increasingly less likely to match into orthopedics relative to White applicants until 2021. In the academic year of 2021-2022, there was an improvement in this trend for all studied underrepresented populations. Although the exact explanation for this is unclear, it is associated with the transition to virtual applicant interactions. The female gender did not appear to be a consistent advantage or disadvantage in the match. Women and Asian applicants were less likely to apply to orthopedics than other specialties.

Correlations among MRI-based cervical and thoracic vertebral bone quality score, CT-based Hounsfield Unit score, and DEXA t-score in assessment of bone mineral density.

BACKGROUND: Further optimization of the validated vertebral bone quality (VBQ) score using magnetic resonance imaging (MRI) may expand its clinical utility for bone mineral density (BMD) assessment. This study evaluated the correlations among cervical and thoracic VBQ scores, the validated Hounsfield Unit (HU) measured on computed tomography (CT), and dual-energy x-ray absorptiometry (DEXA) values. METHODS: We retrieved the medical and radiographic records of 165 patients who underwent synchronous MRI of the cervical and thoracic spine, as well as DEXA and CT imaging of the spine obtained within 1 year of each other between 2015 and 2022. Radiographic data consisted of the MRI-based cervical and thoracic VBQ scores, CT-based HU, and DEXA T-scores of the spine and hip. Patient age, sex, body mass index (BMI), and ethnicity were also obtained. RESULTS: Mean cervical and thoracic VBQ scores were 3.99 ± 1.68 and 3.82 ± 2.11, respectively. Mean HU and DEXA T-scores of the spine and hip were 135.75 ± 60.36, -1.01 ± 1.15, and -0.47 ± 2.27. All correlations among VBQ, HU, and DEXA were insignificant except for weak correlations between cervical and thoracic VBQ, and cervical VBQ and HU. No correlations were observed between radiographic scores and patient age or BMI. No differences based on ethnicity or sex were observed with respect to cervical or thoracic VBQ, HU, or DEXA. CONCLUSION: Cervical and thoracic VBQ scores are distinct from Hounsfield Unit and DEXA values. VBQ scoring in the cervical and thoracic spine is not influenced by patient age, ethnicity, sex, or BMI.

Correlations among Cervical, Thoracic, and lumbar Hounsfield Unit measurements for assessment of bone mineral density.

OBJECTIVE: Bone mineral density assessment using Hounsfield Unit (HU) currently depends upon the availability of computed tomography (CT) of the lumbar spine. The primary aim of this study was to evaluate the associations among HU measurements of the cervical (CHU), thoracic (THU), and lumbar (LHU) spine. The secondary aim of this study was to analyze the influence of patient demographic and anthropometric characteristics on HU measurements. METHODS: Radiographic records of 165 patients who underwent CT of the cervical, thoracic, and lumbar spine were retrieved. The CHU, THU, and LHU were calculated by obtaining the mean signal intensity from the medullary portions of C3-C7, T8-T12, and L1-L4 vertebral bodies. RESULTS: Mean CHU, THU, and LHU values were 266.26 ± 88.69, 165.57 ± 55.06, and 166.45 ± 51.38. Significant differences of 100.69, 99.81, and 0.88 were observed between CHU and THU (p <.001), CHU and LHU (p <.001), and THU and LHU (p =.023). Correlations of 0.574, 0.488, and 0.686 were observed between CHU and THU (p <.001), CHU and LHU (p <.001), and THU and LHU (p <.001). No differences in HU based on sex, age, height, weight, or ethnicity were observed. Multivariate regression models demonstrated R2 values of 0.770 - 0.790 (p <.001) in prediction of LHU. CONCLUSIONS: Hounsfield Unit measurements derived from the cervical and thoracic spine correlate with the validated lumbar Hounsfield Unit. Hounsfield Unit measurements do not vary based on sex, ethnicity, age, height, or weight.

Association Between Vertebral Bone Quality Score and Dual-Energy X-ray Absorptiometry for the Assessment of Bone Mineral Density in Adolescent Patients.

BACKGROUND: The MRI-based vertebral bone quality (VBQ) score is an assessment tool for bone mineral density (BMD) that has been validated in adults against the clinical standard of dual-energy X-ray absorptiometry (DEXA). However, VBQ has yet to be validated against DEXA for use in adolescents. This study evaluated the associations between adolescent VBQ scores, DEXA Z-scores, and BMD values. METHODS: The radiographic records of 63 consecutive patients between the ages of 11 and 21 who underwent MRI of the abdomen and pelvis and DEXA of the spine and hip were retrieved. The collected radiographic data consisted of the MRI-based VBQ score, DEXA Z-score, and BMD values of the femoral neck, L1-4 vertebrae, and total body. The VBQ score was calculated by taking the median signal intensity (MSI) from L1-L4 and the SI of the L3 cerebrospinal fluid (CSF). The VBQ score was derived as the quotient of MSIL1-L4 divided by SICSF. RESULTS: A mean VBQ score of 2.41 ± 0.29 was observed. Strong correlations of -0.749 (p<0.0001) and -0.780 (p<0.0001) were detected between the VBQ score and DEXA femoral neck and spine Z-scores, respectively. Correlations between VBQ score and DEXA femoral neck, spine, and total body BMD scores were -0.559 (p<0.0001), -0.611 (p<0.0001), and -0.516 (p<.0001), respectively. No significant correlations were found between the VBQ score and age, BMI, weight, or height. A mean difference in VBQ score of -0.155 (p=0.035) was observed between sexes. VBQ demonstrated moderate predictive ability for DEXA-derived Z-scores and BMD scores. CONCLUSIONS: VBQ scores were strongly correlated with DEXA Z-scores and moderately correlated with BMD values. The VBQ score can also be used by adolescent patients as an accessory tool to assess bone health.

Morphometric analysis of cervical disc space height and interpedicular distance using computed tomography.

Background: This study utilized computed tomography (CT) to establish normative radiographic morphometric measurements of cervical disc space height (DSH) and interpedicular distance (IPD) and document the influence of patient sex, race, ethnicity, and anthropometric characteristics. Methods: Cervical CTs of 1000 patients between 18 and 35 years of age without known spinal pathology were reviewed. Statistical analyses included the assessment of associations between patient height, weight, sex, race, and ethnicity regarding DSH and IPD. Results: Irrespective of disc level, average DSH measurements were as follows: anterior height of 2.6 ± 1.0 mm, middle height of 4.1 ± 1.2 mm, and posterior height of 1.8 ± 1.0 mm. IPD was only measured between C3 and C7 vertebrae, and irrespective of disc level, the mean IPD measurement was 21.1 ± 1.5 mm. Significant differences for anterior, middle, posterior DSH, and IPD were observed in all disc levels. Significant differences in DSH and IPD were observed for all anthropometric factors of sex, race, and ethnicity relative to vertebral level. Males had significantly larger DSH and IPD measurements across all vertebral levels compared to females. Caucasians had larger DSH and IPD at select vertebral levels compared to African Americans and Hispanics. Conclusion: This study describes measurements of DSH and IPD between C2 and T1 levels in 1000 healthy 18-35-year-old subjects without known pathology. DSH and IPD measurements varied based on patient sex, race, ethnicity, and disc level.

Normative Measurements of L1-S1 Segmental Angulation, Disk Space Height, and Neuroforaminal Dimensions Using Computed Tomography.

BACKGROUND AND OBJECTIVES: To establish normative anatomic measurements of lumbar segmental angulation (SA) and disk space height (DSH) in relation to neuroforaminal dimensions (NFDs), and to uncover the influence of patient demographic and anthropometric characteristics on SA, DSH, and NFDs. METHODS: NFDs, SA, and anterior, middle, and posterior DSH were measured using computed tomography of 969 patients. NFDs were defined as sagittal anterior-to-posterior width, foraminal height, and area. Statistical analyses were performed to assess associations among SA, DSH, NFDs, and patient height, weight, body mass index, sex, and ethnicity. RESULTS: SA and DSH measurements increased moving caudally from L1 to S1. Foraminal width decreased moving caudally from L1 to S1. Foraminal height and area demonstrated unimodal distribution patterns with the largest values clustered at L2-L3 on the right side and L3-L4 on the left. Significant differences in SA, DSH, and NFD measurements were observed based on the disk level. Inconsistent, marginal NFD differences were observed based on laterality. Across all disk levels, only weak-to-moderate correlations were observed between SA and DSH in relation to NFDs. Patient height, weight, and body mass index were only weakly associated with SA, DSH, and NFDs. Based on patient sex, significant differences were observed for SA, DSH, and NFD measurements from L1 to S1, with males demonstrating consistently larger values compared with females. Based on patient race and ethnicity, significant differences in SA and NFD measurements were observed from L1 to S1. CONCLUSION: This study describes 48 450 normative measurements of L1-S1 SA, DSH, and NFDs. These measurements serve as representative models of normal anatomic dimensions necessary for several applications including surgical planning and diagnosis of foraminal stenosis. Normative values of SA and DSH are not moderately or strongly associated with NFDs. SA, DSH, and NFDs are influenced by sex and ethnicity, but are not strongly or moderately influenced by patient anthropometric factors.

Anatomic Parameters for Diagnosing Congenital Lumbar Stenosis Based on Computed Tomography of 1,000 Patients.

INTRODUCTION: Quantitative parameters for diagnosis of congenital lumbar stenosis (CLS) have yet to be universally accepted. This study establishes parameters for CLS using CT, assessing the influences of patient sex, race, ethnicity, and anthropometric characteristics. METHODS: Interpedicular distance (IPD), pedicle length, canal diameter, and canal area were measured using 1,000 patients between 18 and 35 years of age who were without spinal pathology. RESULTS: Irrespective of disk level, threshold values for CLS were 16.1 mm for IPD, 3.9 mm for pedicle length, 11.5 mm for canal diameter, and 142.5 mm2 for canal area. Notable differences based on patient sex were observed, with men demonstrating larger CLS threshold values with respect to IPD and canal area across all vertebral levels from L1 to L5. Based on patient anthropometric factors, no strong or moderate associations were observed between any spinal measurement and patient height, weight, or body mass index across all levels from L1 to L5. However, notable differences were observed based on patient race and ethnicity from L1 to L5. Asian patients demonstrated the largest pedicle lengths, followed by White, Hispanic, and Black patients in descending order. White patients demonstrated the largest IPD, canal AP diameter, and canal area, followed by Asian, Hispanic, and Black patients in descending order. Black patients demonstrated the smallest values across all anatomic measurements relative to Asian, White, and Hispanic patients. CONCLUSION: This study reports 25,000 measurements of lumbar central canal dimensions to establish quantitative thresholds for the diagnosis of CLS. Although not influenced by patient height, weight, or body mass index as one might intuit, canal dimensions were influenced by patient sex, race, and ethnicity. These findings may help explain differences in predisposition or prevalence of lumbar nerve root compression among patients of different races, which can be important when considering rates of surgery and access to care.

Assessment of Anteroposterior Diameter and Interpedicular Distance in the Approximation of Cervical Spinal Canal Area.

Rationale and objectives This study seeks to generate a model based on two linear measurements, anteroposterior (AP) diameter and interpedicular (IPD) distance, to approximate the cervical central canal (CCC) area in a non-pathologic patient population by employing area calculations of shapes such as ellipse, rectangle, and triangle. Secondarily, this study aims to generate second-order approximations (SOAs), using the aforementioned shape approximations, to increase the utility of this linear measurement-based model. Methods The authors reviewed medical and radiographic records of patients aged 18-35 who received computed tomography (CT) imaging of the cervical spine to collect AP diameter, IPD distance, and area of the CCC from C2-3 to C6-7. Subsequently, shape approximations were calculated for each patient at all cervical spine levels. Lastly, SOAs were generated by combining optimal ratios of shape approximations to improve the statistical reliability of approximations. Results The ellipse shows the closest approximation to manual measurements of the individual shape approximations. Percent error analysis demonstrated the superiority of the ellipse, followed by the rectangle, and lastly the triangular approximation. The highest correlation of approximations was observed at C6-7. All individual shape approximations demonstrated statistical differences from manual measurements. SOAs combining ellipse and rectangle measurements demonstrated superior accuracy and were not statistically different from manual measurements. Conclusion Individual shape approximations based on AP diameter and IPD distance show some value as a model for the assessment of the CCC area. SOAs demonstrated greater utility than individual shape approximations and show promise as a linear measurement-based tool to assess the CCC area.

Large-scale F0 CRISPR screens in vivo using MIC-Drop.

The zebrafish is a powerful model system for studying animal development, for modeling genetic diseases, and for large-scale in vivo functional genetics. Because of its ease of use and its high efficiency in targeted gene perturbation, CRISPR-Cas9 has recently gained prominence as the tool of choice for genetic manipulation in zebrafish. However, scaling up the technique for high-throughput in vivo functional genetics has been a challenge. We recently developed a method, Multiplexed Intermixed CRISPR Droplets (MIC-Drop), that makes large-scale CRISPR screening in zebrafish possible. Here, we outline the step-by-step protocol for performing functional genetic screens in zebrafish by using MIC-Drop. MIC-Drop uses multiplexed single-guide RNAs to generate biallelic mutations in injected zebrafish embryos, allowing genetic screens to be performed in F0 animals. Combining microfluidics and DNA barcoding enables simultaneous targeting of tens to hundreds of genes from a single injection needle, while also enabling retrospective and rapid identification of the genotype responsible for an observed phenotype. The primary target audiences for MIC-Drop are developmental biologists, zebrafish geneticists, and researchers interested in performing in vivo functional genetic screens in a vertebrate model system. MIC-Drop will also prove useful in the hands of chemical biologists seeking to identify targets of small molecules that cause phenotypic changes in zebrafish. By using MIC-Drop, a typical screen of 100 genes can be conducted within 2-3 weeks by a single user.

Anatomic Assessment of L1-S1 Neuroforaminal Dimensions Using Computed Tomography in 1,000 Patients: A Follow-Up Study.

OBJECTIVES: While the radiographic criteria for diagnosing central lumbar stenosis are well described, criteria for diagnosing neuroforaminal stenosis (NFS) are unclear. Prior research has utilized magnetic resonance imaging (MRI) to characterize neuroforaminal dimensions (NFDs). However, this approach has inherent limitations that can adversely impact measurement accuracy. Existing literature on the use of computed tomography (CT) to investigate normal NFDs is limited. The purpose of the present study was to describe normal lumbar NFDs that would aid in the establishment of objective quantitative criteria for the diagnosis of NFS. METHODS: This study evaluated CT imaging of 494 female and 506 male subjects between 18 and 35 years of age to determine normal NFDs, specifically the sagittal anteroposterior width, craniocaudal height, and area. Statistical analyses were performed to assess differences in NFDs according to variables including sex, height, weight, body mass index, and ethnicity. RESULTS: Without differentiating between sides or disc levels, mean NFDs were 8.71 mm for sagittal anteroposterior width, 17.73 mm for craniocaudal height, and 133.26 mm2 for area (n = 10,000 measurements each). Male subjects had larger NFDs than females at multiple levels. Asian and Caucasian subjects had larger NFDs than Hispanic and African American subjects at multiple levels. There were no associations between NFDs and anthropometric factors. CONCLUSIONS: The present study describes normal lumbar NFDs in young, healthy patients. NFDs were influenced by sex and ethnicity but not by anthropometric factors.

The Reoperation, Readmission, and Complication Rates at 30 Days Following Lumbar Decompression for Cauda Equina Syndrome.

Background and objective Cauda equina syndrome (CES) is considered a surgical emergency, and its primary treatment involves decompression of the nerve roots, typically in the form of discectomy or laminectomy. The primary aim of this study was to determine the complication, reoperation, and readmission rates within 30 days of surgical treatment of CES secondary to disc herniation by using the PearlDiver database (PearlDiver Technologies, Colorado Springs, CO). The secondary aim was to assess preoperative risk factors for a higher likelihood of complication occurrence within 30 days of surgery for CES. Methods A total of 524 patients who had undergone lumbar discectomy or laminectomy for CES were identified. The outcome measures were 30-day reoperation rate for revision decompression or lumbar fusion, and 30-day readmissions related to surgery. The patient data collected included medical history and surgical data including the number of levels of discectomy and laminectomy. Results Based on our findings, intraoperative dural tears, valvular heart disease, and fluid and electrolyte abnormalities were significant risk factors for readmission to the hospital within 30 days following surgery for CES. The most common postoperative complications were as follows: visits to the emergency department (63 patients, 12%), surgical site infection (21 patients, 4%), urinary tract infection (14 patients, 3%), and postoperative anemia (11 patients, 2%). Conclusions In the 30-day period following lumbar decompression for cauda equina syndrome, our findings demonstrated an 8% reoperation rate and 17% readmission rate. Although CES is considered an indication for urgent surgery, gaining awareness about reoperation, readmission, and complication rates in the immediate postoperative period may help calibrate expectations and inform medical decision-making.

Applications of Interpedicular Distance and Anteroposterior Diameter in the Approximation of the Spinal Canal Area.

INTRODUCTION:  Advancements within the field of medicine revolve around increasing the efficiency of diagnosing and subsequently treating patients. One such advancement is measurements of the central canal using artificial intelligence (AI). The authors propose the possibility of AI measuring two linear distances followed by a subsequent approximation via an area equation. The lumbar spinal canal was approximated by an area calculation using the interpedicular distance (IPD) and anteroposterior diameter (AP diameter). The three shapes evaluated were an ellipse, triangle, and rectangle. METHODS:  IPD, AP diameter, and spinal canal area from L1-L5 were measured in 555 patients using the IMPAX6 (Mortsel, Belgium: Agfa-Gevaert) picture archiving and communication system. Subsequently, an approximated area of the lumbar spinal canal, assuming an ellipse shape, was calculated using ellipse equation/approximation. Triangular and rectangular approximations were done using triangle equation/approximation and rectangle equation/approximation, respectively. The equations used are the geometric equations for the area of each shape described. For example, the triangular approximation used the IPD as the base of the triangle and the AP diameter as the height. Thus, the area approximation was calculated by half of the IPD times the AP diameter. RESULTS:  The percent error of the ellipse approximation was the lowest with a range of error from 8.44% at L1 to 15.51% at L5. The triangle approximation again was the second most accurate with a range of error starting at -26.46% at L5 to -30.96% at L1. Lastly, the percentage errors of the rectangle approximation began at 38.07% at L1 to 47.07% at L5. The ellipse and rectangle approximation consistently overestimated the area of the spinal canal, while the opposite was true for the triangle approximation. A combination of these approximations could be used to construct a second-order approximation. The approximations were all highly correlated with the authors' manual measurements. Approximations at the L2 vertebrae were highest with a correlation of 0.934 closely followed by all approximations at L5 with a value of 0.931. Approximations were least correlated with the L4 vertebrae with a value of 0.905. CONCLUSION: The correlation between the approximation equations and the measured values is significantly related. The ellipse equation best predicted the area of the spinal canal followed by the triangle and then the rectangle approximation. The percent error difference of the ellipse approximation at L1 was similar in error compared to other causes of measurement error. Continued investigation into a second-order approximation may yield a more accurate approximation.

Ablation of mpeg+ Macrophages Exacerbates mfrp-Related Hyperopia.

Purpose: Proper refractive development of the eye, termed emmetropization, is critical for focused vision and is impacted by both genetic determinants and several visual environment factors. Improper emmetropization caused by genetic variants can lead to congenital hyperopia, which is characterized by small eyes and relatively short ocular axial length. To date, variants in only four genes have been firmly associated with human hyperopia, one of which is MFRP. Zebrafish mfrp mutants also have hyperopia and, similar to reports in mice, exhibit increased macrophage recruitment to the retina. The goal of this research was to examine the effects of macrophage ablation on emmetropization and mfrp-related hyperopia. Methods: We utilized a chemically inducible, cell-specific ablation system to deplete macrophages in both wild-type and mfrp mutant zebrafish. Spectral-domain optical coherence tomography was then used to measure components of the eye and determine relative refractive state. Histology, immunohistochemistry, and transmission electron microscopy were used to further study the eyes. Results: Although macrophage ablation does not cause significant changes to the relative refractive state of wild-type zebrafish, macrophage ablation in mfrp mutants significantly exacerbates their hyperopic phenotype, resulting in a relative refractive error 1.3 times higher than that of non-ablated mfrp siblings. Conclusions: Genetic inactivation of mfrp leads to hyperopia, as well as abnormal accumulation of macrophages in the retina. Ablation of the mpeg1-positive macrophage population exacerbates the hyperopia, suggesting that macrophages may be recruited in an effort help preserve emmetropization and ameliorate hyperopia.

Somatic Mutations of lats2 Cause Peripheral Nerve Sheath Tumors in Zebrafish.

The cellular signaling pathways underlying peripheral nerve sheath tumor (PNST) formation are poorly understood. Hippo signaling has been recently implicated in the biology of various cancers, and is thought to function downstream of mutations in the known PNST driver, NF2. Utilizing CRISPR-Cas9 gene editing, we targeted the canonical Hippo signaling kinase Lats2. We show that, while germline deletion leads to early lethality, targeted somatic mutations of zebrafish lats2 leads to peripheral nerve sheath tumor formation. These peripheral nerve sheath tumors exhibit high levels of Hippo effectors Yap and Taz, suggesting that dysregulation of these transcriptional co-factors drives PNST formation in this model. These data indicate that somatic lats2 deletion in zebrafish can serve as a powerful experimental platform to probe the mechanisms of PNST formation and progression.