Armin Arshi

Automated cellular sample preparation using a Centrifuge-on-a-Chip

The standard centrifuge is a laboratory instrument widely used by biologists and medical technicians for preparing cell samples. Efforts to automate the operations of concentration, cell separation, and solution exchange that a centrifuge performs in a simpler and smaller platform have had limited success. Here, we present a microfluidic chip that replicates the functions of a centrifuge without moving parts or external forces. The device operates using a purely fluid dynamic phenomenon in which cells selectively enter and are maintained in microscale vortices. Continuous and sequential operation allows enrichment of cancer cells from spiked blood samples at the mL min(-1) scale, followed by fluorescent labeling of intra- and extra-cellular antigens on the cells without the need for manual pipetting and washing steps. A versatile centrifuge-analogue may open opportunities in automated, low-cost and high-throughput sample preparation as an alternative to the standard benchtop centrifuge in standardized clinical diagnostics or resource poor settings.

Haemogenic endocardium contributes to transient definitive haematopoiesis

Hematopoietic cells arise from spatiotemporally restricted domains in the developing embryo. Although studies of non-mammalian animal and in vitro embryonic stem cell models suggest a close relationship among cardiac, endocardial, and hematopoietic lineages, it remains unknown whether the mammalian heart tube serves as a hemogenic organ akin to the dorsal aorta. Here we examine the hemogenic activity of the developing endocardium. Mouse heart explants generate myeloid and erythroid colonies in the absence of circulation. Hemogenic activity arises from a subset of endocardial cells in the outflow cushion and atria earlier than in the aorta-gonad-mesonephros region, and is transient and definitive in nature. Interestingly, key cardiac transcription factors, Nkx2-5 and Isl1, are expressed in and required for the hemogenic population of the endocardium. Together, these data suggest that a subset of endocardial/endothelial cells expressing cardiac markers serve as a de novo source for transient definitive hematopoietic progenitors.

Incidence of Acute Postoperative Infections Requiring Reoperation After Arthroscopic Shoulder Surgery

Background: An acute infection after arthroscopic shoulder surgery is a rare but serious complication. Previous studies estimating the incidence of infections after arthroscopic surgery have been conducted, but the majority of these had either relatively small study groups or were not specific to shoulder arthroscopic surgery. Purpose: To investigate the incidence of acute infections after arthroscopic shoulder surgery and compare infection rates by age group, sex, geographic region, and specific procedures. Study Design: Case series; Level of evidence, 4. Methods: A retrospective review of a large insurance company database was performed for all shoulder arthroscopic surgeries performed in the United States between 2004 and 2009 that required additional surgery for infections within 30 days. The data were stratified by sex, age group, and region. Data were also stratified for specific procedures (capsulorrhaphy, treatment for superior labrum anterior-posterior tears, claviculectomy, decompression, and rotator cuff repair) and used to assess the variation in the incidence of infections across different arthroscopic shoulder procedures. Linear regression was used to determine the significance of differences in the data from year to year. χ2 analysis was used to assess the statistical significance of variations among all groups. Poisson regression analysis with exposure was used to determine significant differences in a pairwise comparison between 2 groups. Results: The total number of arthroscopic shoulder surgeries performed was 165,820, and the number of infections requiring additional surgery was 450, resulting in an overall infection rate of 0.27%. The incidence of infections varied significantly across age groups (P < .001); the infection rate was highest in the ≥60-year age group (0.36%) and lowest in the 10- to 39-year age group (0.18%). The incidence of infections also varied by region (P < .001); the incidence was highest in the South (0.37%) and lowest in the Midwest (0.11%). The incidence of infection treatments was also significantly different between different arthroscopic procedures (P < .01) and was highest for rotator cuff repair (0.29%) and lowest for capsulorrhaphy (0.16%). The incidence did not significantly vary by year or sex. Conclusion: The overall infection rate for all arthroscopic shoulder procedures was 0.27%. The incidence was highest in elderly patients, in the South, and for rotator cuff repair. The incidence was lowest in young patients, in the Midwest, and for capsulorrhaphy. In general, shoulder arthroscopic surgery in this study population had a low rate of reoperation in the acute period.

Rigid microenvironments promote cardiac differentiation of mouse and human embryonic stem cells

Abstract While adult heart muscle is the least regenerative of tissues, embryonic cardiomyocytes are proliferative, with embryonic stem (ES) cells providing an endless reservoir. In addition to secreted factors and cell–cell interactions, the extracellular microenvironment has been shown to play an important role in stem cell lineage specification, and understanding how scaffold elasticity influences cardiac differentiation is crucial to cardiac tissue engineering. Though previous studies have analyzed the role of matrix elasticity on the function of differentiated cardiomyocytes, whether it affects the induction of cardiomyocytes from pluripotent stem cells is poorly understood. Here, we examine the role of matrix rigidity on cardiac differentiation using mouse and human ES cells. Culture on polydimethylsiloxane (PDMS) substrates of varied monomer-to-crosslinker ratios revealed that rigid extracellular matrices promote a higher yield of de novo cardiomyocytes from undifferentiated ES cells. Using a genetically modified ES system that allows us to purify differentiated cardiomyocytes by drug selection, we demonstrate that rigid environments induce higher cardiac troponin T expression, beating rate of foci, and expression ratio of adult α- to fetal β- myosin heavy chain in a purified cardiac population. M-mode and mechanical interferometry image analyses demonstrate that these ES-derived cardiomyocytes display functional maturity and synchronization of beating when co-cultured with neonatal cardiomyocytes harvested from a developing embryo. Together, these data identify matrix stiffness as an independent factor that instructs not only the maturation of already differentiated cardiomyocytes but also the induction and proliferation of cardiomyocytes from undifferentiated progenitors. Manipulation of the stiffness will help direct the production of functional cardiomyocytes en masse from stem cells for regenerative medicine purposes.

Epidemiology and Treatment of Lacrimal Gland Tumors: A Population-Based Cohort Analysis

IMPORTANCE Primary tumors of the lacrimal gland are rare and are associated with substantial morbidity and mortality. The literature regarding these tumors is limited to case series and case reports. OBJECTIVE To examine the incidence, treatment, and overall survival (OS) and disease-specific survival (DSS) of patients with cancer of the lacrimal gland. DESIGN, SETTING, AND PARTICIPANTS Population-based cohort analysis using the Surveillance, Epidemiology, and End Results (SEER) database to identify patients with primary tumors of the lacrimal gland from 1973 to 2010. MAIN OUTCOMES AND MEASURES Overall survival and DSS. RESULTS A total of 321 patients with nonlymphoid tumors of the lacrimal gland were identified. The most common histological subtypes were adenoid cystic carcinoma (ACC) (32.1%) and squamous cell carcinoma (SCC) (29.9%). Survival analysis revealed a 5-year OS and DSS for all lacrimal gland tumors of 60% and 75%, respectively. On univariate analysis, low tumor grade (P = .04) and surgical treatment (P < .001) were associated with significantly better OS. For ACC tumors, surgery (P = .009), but not radiotherapy (P = .44), was found to significantly improve OS. For SCC tumors, surgical treatment significantly improved both OS (P < .001) and DSS (P = .004); radiation therapy also significantly improved OS (P = .03). Using a multivariable analysis model, age (hazard ratio [HR], 1.03 [95% CI, 1.01-1.04]; P < .001), surgery (HR, 0.43 [95% CI, 0.25-0.75]; P = .003), and T stage at presentation (HR, 1.18 [95% CI, 1.01-1.37]; P = .03) were found to be independent predictors of OS. For ACC alone, age (HR, 1.04 [95% CI, 1.02-1.06]; P < .001) and surgery (HR, 0.35 [95% CI, 0.13-0.91]; P = .03) were independent predictors of OS. For SCC, age (HR, 1.05 [95% CI, 1.02-1.09]; P = .005), surgical resection (HR, 0.31 [95% CI, 0.12-0.83]; P = .02), and radiation therapy (HR, 0.33 [95% CI, 0.14-0.80]; P = .01) were independent predictors of OS. CONCLUSIONS AND RELEVANCE Our study demonstrates that ACC is the most common malignant epithelial neoplasm of the lacrimal gland. Determinants of survival for tumors of the lacrimal gland include age at diagnosis and surgical therapy. Radiation therapy is associated with improved DSS in SCC but not in ACC.

Importance of Tumor Grade in Esthesioneuroblastoma Survival: A Population-Based Analysis

IMPORTANCE There is a need for larger studies characterizing the effect of tumor grade on survival for patients with esthesioneuroblastoma. OBJECTIVE To investigate prognostic factors for survival in patients diagnosed with esthesioneuroblastoma, including emphasis on tumor grade. DESIGN, SETTING, AND PARTICIPANTS Retrospective, population-based cohort study of patients in the Surveillance, Epidemiology, and End Results (SEER) tumor registry who were diagnosed with esthesioneuroblastoma from January 1, 1973, to January 1, 2010. The last date of survival follow-up was 2013. MAIN OUTCOMES AND MEASURES Overall and disease-specific survival. RESULTS The cohort included 281 patients with a mean age of 52 years. There were 154 males (54.8%) and 127 females (45.2%). Kaplan-Meier analysis demonstrated an overall and disease-specific survival rate of 61% and 70% at 5 years and 50% and 64% at 10 years, respectively. Multivariable Cox regression analysis showed that advanced tumor grade and modified Kadish stage (hazard ratio, 4.930; 95% CI, 2.635-9.223; P = .001) portended worse disease-specific survival, and radiation therapy (hazard ratio, 0.499; 95% CI, 0.272-0.916; P = .03) improved disease-specific survival. Patients with low-grade tumors (grades I and II) demonstrated an overall and disease-specific survival rate of 84% and 92% at 5 years and 67% and 87% at 10 years, respectively. Multivariable analysis of low-grade tumors only revealed receiving surgery (P = .004) as an independent positive predictor of disease-specific survival. High-grade tumors (grades III and IV) demonstrated overall and disease-specific survival of 40% and 50% at 5 years and 34% and 43% at 10 years, respectively. Multivariable analysis of high-grade tumors showed modified Kadish stage (hazard ratio, 2.025; 95% CI, 1.430-2.866; P < .001) predicted worse disease-specific survival, and radiation therapy (hazard ratio, 0.433; 95% CI, 0.228-0.864; P = .02) independently predicted improved disease-specific survival. CONCLUSIONS AND RELEVANCE Here, to our knowledge, we report the largest study investigating prognostic factors for survival, with the inclusion of tumor grade, in patients diagnosed with esthesioneuroblastoma. Patients with high-grade tumors had substantially worse survival rates than patients with low-grade tumors. Multivariable analysis revealed only receiving surgery as an independent predictor of disease-specific survival for patients with low-grade tumors, while modified Kadish stage and postoperative radiation therapy were significant factors in predicting disease-specific survival in patients with high-grade tumors. This study highlights the growing evidence that tumor grade should be a key factor in predicting survival in patients with esthesioneuroblastoma, and that adjuvant radiation therapy improves survival rates among patients with high-grade, but not low-grade, tumors.

Characteristics and Prognostic Factors of Osteosarcoma of the Jaws: A Retrospective Cohort Study

IMPORTANCE Osteosarcoma of the jaws is rare and clinically distinct from osteosarcoma of the long bones of the body with different treatment and outcomes. The literature on these tumors is limited to case reports and small case series mostly from single institutions. We used data from the population-based national Surveillance, Epidemiology and End Results (SEER) cancer registry to determine the epidemiology and prognostic factors associated with osteosarcoma of the jaws. OBJECTIVE To investigate the epidemiologic characteristics and prognostic factors for survival in patients diagnosed with osteosarcoma of the jaws. DESIGN, SETTING, AND PARTICIPANTS A retrospective, population-based cohort study of 541 patients in the SEER tumor registry diagnosed with osteosarcoma of the jaws from 1973 through 2011 were reviewed. EXPOSURES Patients had been treated with surgery, radiation, both, or neither. MAIN OUTCOMES AND MEASURES Overall and disease-specific survival. RESULTS A total of 541 patients diagnosed with osteosarcoma of the jaws were identified (49.9% male and 50.1% female, with a mean age of 41.3 years). Kaplan-Meier analysis demonstrated an overall survival (OS) and disease-specific survival (DSS) of 53% and 62%, respectively, at 5 years and 35% and 54%, respectively, at 10 years. Multivariate Cox regression analysis revealed that independent predictors of OS and DSS included age at diagnosis (hazard ratio [HR], 1.03; 95% CI, 1.02-1.04 [P < .001] for OS; and HR, 1.03; 95% CI, 1.02-1.05 [P < .001] for DSS); stage at presentation (HR, 1.37; 95% CI, 1.10-1.71 [P = .006] for OS; and HR, 1.34; 95% CI, 1.01-1.76 [P = .04] for DSS); and surgical resection (HR, 0.31; 95% CI, 0.16-0.60 [P < .001] for OS; and HR, 0.22; 95% CI, 0.09-0.56 [P = .001] for DSS). Tumor size was not significant for OS (HR, 1.00; 95% CI, 1.00-1.01 [P = .11] but significant for DSS (HR, 1.01; 95% CI, 1.00-1.01 [P = .003]). CONCLUSIONS AND RELEVANCE To our knowledge, this is the largest study to date investigating prognostic factors for survival in patients diagnosed with osteosarcoma of the jaws. Determinants of survival include age at diagnosis, stage at presentation, tumor size, and surgical therapy. Radiation therapy was not associated with improved survival, reflecting the controversy surrounding its use in clinical literature.

Esthesioneuroblastoma: An Update on the UCLA Experience, 2002–2013

Objectives To profile the clinical presentation and treatment results of esthesioneuroblastomas at the University of California, Los Angeles (UCLA), from 2002 to 2013. Design Retrospective review. Setting Tertiary academic institution. Participants Forty-one patients with esthesioneuroblastomas treated at UCLA. Main Outcome Measures Overall survival (OS) and recurrence-free survival (RFS). Results Thirty-six patients were included with a mean age of 50.1 years and a median duration of follow-up of 33 months. The 5-year RFS and OS were 54% and 82%, respectively. Modified Kadish stage was the only factor identified to affect OS. Multivariate analysis demonstrated that tumor grade was the only factor that had an independent impact on RFS. There was no statistical difference in survival among the surgical approaches chosen. Conclusions The updated data on the UCLA experience reveals that all three surgical approaches chosen provide comparable survival, although longer follow-up will be needed to ascertain if these findings hold true. The endoscopic approach had a statistically significant decrease in length of hospital stay and a trend toward reduced blood loss, intensive care unit admission, and complications. The modified Kadish staging was the only factor identified to predict OS. Multivariate analysis revealed that tumor grade was an independent predictor of recurrence; therefore, its importance should be emphasized in future staging systems.

In vitro and in vivo evaluation of heparin mediated growth factor release from tissue-engineered constructs for anterior cruciate ligament reconstruction.

Anterior cruciate ligament (ACL) rupture is a common injury often necessitating surgical treatment with graft reconstruction. Due to limitations associated with current graft options, there is interest in a tissue‐engineered substitute for use in ACL regeneration. While they represent an important step in translation to clinical practice, relatively few in vivo studies have been performed to evaluate tissue‐engineered ACL grafts. In the present study, we immobilized heparin onto electrospun polycaprolactone scaffolds as a means of incorporating basic fibroblast growth factor (bFGF) onto the scaffold. In vitro, we demonstrated that human foreskin fibroblasts (HFFs) cultured on bFGF‐coated scaffolds had significantly greater cell proliferation. In vivo, we implanted electrospun polycaprolactone grafts with and without bFGF into athymic rat knees. We analyzed the regenerated ACL using histological methods up to 16 weeks post‐implantation. Hematoxylin and eosin staining demonstrated infiltration of the grafts with cells, and picrosirius red staining demonstrated aligned collagen fibers. At 16 weeks postop, mechanical testing of the grafts demonstrated that the grafts had approximately 30% the maximum load to failure of the native ACL. However, there were no significant differences observed between the graft groups with or without heparin‐immobilized bFGF. While this study demonstrates the potential of a regenerative medicine approach to treatment of ACL rupture, it also demonstrates that in vitro results do not always predict what will occur in vivo.

Operative Management of Patellar Instability in the United States: An Evaluation of National Practice Patterns, Surgical Trends, and Complications

Background: Treatment of patellofemoral instability has evolved as our understanding of the relevant pathoanatomy has improved. In light of these developments, current practice patterns and management trends have likely changed to reflect these advancements; however, this has not been evaluated in a formal study. Purpose: To determine nationwide patient demographics, surgical trends, and postoperative complications associated with the operative management of patellar instability surgery. Study Design: Descriptive epidemiological study. Methods: A large private-payer database (PearlDiver) comprising patients covered by Humana and United Healthcare insurance policies was retrospectively reviewed using Current Procedural Terminology (CPT) codes to identify patients who underwent surgery for patellar instability. The study cohort was established by querying for patients billed under CPT codes 27420, 27422, or 27427 while satisfying the diagnostic requirement of patellar instability (International Classification of Diseases–9th Revision codes 718.36, 718.86, or 836.3). Patient demographics, surgical trends, concomitant procedures, and postoperative complications were determined. Results: A total of 6190 patients underwent surgical management for patellar instability. Adolescents (age range, 10-19 years) represented 51.5% of cases, and 59.6% were female. The number of patellar instability procedures increased annually over the study period in both the Humana (P = .004, R 2 = 0.76) and United Healthcare (P = .097, R 2 = 0.54) cohorts. The most common concomitant procedures were lateral retinacular release (43.7%), chondroplasty (31.1%), tibial tubercle osteotomy (13.1%), removal of loose bodies (10.5%), osteochondral grafting (9.5%), and microfracture surgery (9.5%). Manipulation under anesthesia was required in 4.6% of patients within 1 year. Patellar fracture within 1 year and infection within 30 days occurred in 2.1% and 1.2% of patients, respectively. Conclusion: Patellar instability surgery has increased over the past decade. This finding may be attributed to growing clinical evidence to support these procedures as well as increased surgeon familiarity and comfort with these specific techniques. We observed an unexpectedly high rate of concomitant lateral retinacular release. Overall, the rates of commonly recognized complications (stiffness, patellar fracture, and postoperative infection) were similar to those observed in smaller case series.