Using the Stratum-Specific Likelihood Ratio Method to Derive Outcome-Based Hospital Volume Categories for Total Knee Replacement.

BACKGROUND: Evidence of higher hospital volume being associated with improved outcomes for patients undergoing total knee replacement (TKR) is mostly based on arbitrary distribution-based thresholds. OBJECTIVE: We aimed to define outcome-based volume thresholds using data from a national database. METHODS: We used the MedPAR Limited Data Set inpatient data from 2010-2015 to identify patients who had undergone primary TKR. Surgical and TKR specific complications occurring within the index hospitalization and all-cause readmission within 90 days were considered adverse events. We derived an average annual TKR case volume for each hospital and applied the stratum-specific likelihood ratio method to determine volume categories indicative of a similar likelihood of 90-day post-operative complications. Hierarchical multivariable logistic regression with a random intercept for hospital nested within study year and adjusted for patient and hospital characteristics was performed to determine if these volume thresholds were still associated with the odds of 90-day readmission for complications after adjustment. RESULTS: SSLR analysis yielded 4 hospital volume categories based on the likelihood of 90-day postoperative complications: 1-31 (low), 32-127 (medium), 128-248 (high), and 429+ (very high) TKRs performed per year. The results of the hierarchical multivariable logistic regression showed significantly increased odds of 90-day complications at lower volume categories. Sensitivity analyses confirmed our main findings. CONCLUSIONS: This study is the first to provide national-level volume categories that are evidence-based. Publicizing these thresholds may enhance quality measures available to patients, providers, and payors.

Survival outcomes in pediatric patients with metastatic Ewing sarcoma who achieve a rapid complete response of pulmonary metastases.

PURPOSE: Our objectives were to compare overall survival (OS) and pulmonary relapse between patients with metastatic Ewing sarcoma (EWS) at diagnosis who achieve rapid complete response (RCR) and those with residual pulmonary nodules after induction chemotherapy (non-RCR). PATIENTS AND METHODS: This retrospective cohort study included children under 20 years with metastatic EWS treated from 2007 to 2020 at 19 institutions in the Pediatric Surgical Oncology Research Collaborative. Chi-square tests were conducted for differences among groups. Kaplan-Meier curves were generated for OS and pulmonary relapse. RESULTS: Among 148 patients with metastatic EWS at diagnosis, 61 (41.2%) achieved RCR. Five-year OS was 71.2% for patients who achieved RCR, and 50.2% for those without RCR (p = .04), and in multivariable regression among patients with isolated pulmonary metastases, RCR (hazards ratio [HR] 0.42; 95% confidence interval [CI]: 0.17-0.99) and whole lung irradiation (WLI) (HR 0.35; 95% CI: 0.16-0.77) were associated with improved survival. Pulmonary relapse occurred in 57 (37%) patients, including 18 (29%) in the RCR and 36 (41%) in the non-RCR groups (p = .14). Five-year pulmonary relapse rates did not significantly differ based on RCR (33.0%) versus non-RCR (47.0%, p = .13), or WLI (38.8%) versus no WLI (46.0%, p = .32). DISCUSSION: Patients with EWS who had isolated pulmonary metastases at diagnosis had improved OS if they achieved RCR and received WLI, despite having no significant differences in rates of pulmonary relapse.

Neighborhood Racial and Ethnic Predominance, Child Opportunity, and Violence-Related Mortality among Children and Adolescents in Chicago.

Our objective was to determine whether Child Opportunity Index (COI), a measure of neighborhood socioeconomic and built environment specific to children, mediated the relationship of census tract Black or Hispanic predominance with increased rates of census tract violence-related mortality. The hypothesis was that COI would partially mediate the relationship. This cross-sectional study combined data from the American Community Survey 5-year estimates, the COI 2.0, and the Illinois Violent Death Reporting System 2015-2019 for the City of Chicago. Individuals ages 0-19 years were included. The primary exposure was census tract Black, Hispanic, White, and other race predominance (> 50% of population). The primary outcome was census tract violence-related mortality. A mediation analysis was performed to evaluate the role of COI as a potential mediator. Multivariable logistic regression modeling census tract violence-related mortality demonstrated a direct effect of census tract Black predominance (adjusted odds ratio [aOR] 2.59, 95% confidence interval [CI] 1.30-5.14) on violence-related mortality compared to White predominance. There was no association of census tract Hispanic predominance with violence-related mortality compared to White predominance (aOR 1.57, 95% CI 0.88-2.84). Approximately 64.9% (95% CI 60.2-80.0%) of the effect of census tract Black predominance and 67.9% (95% CI 61.2-200%) of the effect of census tract Hispanic predominance on violence-related mortality was indirect via COI. COI partially mediated the effect of census tract Black and Hispanic predominance on census tract violence-related mortality. Interventions that target neighborhood social and economic factors should be considered to reduce violence-related mortality among children and adolescents.

Association of Prophylactic Antibiotics With Early Infectious Complications in Children With Cancer Undergoing Central Venous Access Device Placement.

OBJECTIVE: To evaluate the impact of prophylactic antibiotics on early infectious complications after central venous access device (VAD) placement in children with cancer. SUMMARY OF BACKGROUND DATA: Despite the frequency of VAD procedures in children, the effectiveness of prophylactic antibiotics for reducing infectious complications is unknown. METHODS: This was a retrospective cohort study of children with cancer undergoing central VAD placement identified in the Pediatric Health Information System database between 2017-2021. The primary outcome was the rate of early infectious complications (composite surgical site infections, central line-associated bloodstream infections, and bacteremia). Multivariable logistic regression was used to evaluate factors associated with early infection, and heterogeneity of treatment effect of prophylactic antibiotics was compared across subgroups. RESULTS: 9,216 patients were included (6,058 ports and 3,158 tunneled lines). Prophylactic antibiotics were associated with lower early infectious complications overall (1.3% vs. 2.4%; OR 0.55 [95% C.I. 0.39-0.79], P<0.001), an effect demonstrated for tunneled lines (OR 0.59, 95% C.I.: 0.41-0.84) but not ports (OR 3.01, 95% C.I.: 0.66-13.78). On multivariate analysis, prophylactic antibiotics (OR 0.67, 95% C.I.: 0.45-0.97) and solid tumors (OR 0.38, 95% C.I.: 0.22-0.64) were associated with reduced odds of early infections, while tunneled lines (OR 20.78, 95% C.I.: 9.83-43.93) and acute myelogenous leukemia (OR 2.37, 95% C.I.: 1.58-3.57) had increased odds. CONCLUSIONS: Prophylactic antibiotics are associated with reduced early infectious complications after central VAD placement overall. Despite recommendations from multiple national organizations against prophylactic antibiotics, these findings suggest a benefit in children with malignancy undergoing tunneled line placement.

Phosphorylation potential of Drosophila E-Cadherin intracellular domain is essential for development and adherens junction biosynthetic dynamics regulation.

Phosphorylation of a highly conserved serine cluster in the intracellular domain of E-Cadherin is essential for binding to ß-Catenin in vitro In cultured cells, phosphorylation of specific serine residues within the cluster is also required for regulation of adherens junction (AJ) stability and dynamics. However, much less is known about how such phosphorylation of E-Cadherin regulates AJ formation and dynamics in vivo In this report, we generated an extensive array of Drosophila E-Cadherin (DE-Cad) endogenous knock-in alleles that carry mutations targeting this highly conserved serine cluster. Analyses of these mutations suggest that the overall phosphorylation potential, rather than the potential site-specific phosphorylation, of the serine cluster enhances the recruitment of ß-Catenin by DE-Cad in vivo Moreover, phosphorylation potential of the serine cluster only moderately increases the level of ß-Catenin in AJs and is in fact dispensable for AJ formation in vivo Nonetheless, phosphorylation-dependent recruitment of ß-Catenin is essential for development, probably by enhancing the interactions between DE-Cad and α-Catenin. In addition, several phospho-mutations dramatically reduced the biosynthetic turnover rate of DE-Cad during apical-basal polarization, and such biosynthetically stable DE-Cad mutants specifically rescued the polarity defects in embryonic epithelia lacking the polarity proteins Stardust and Crumbs.

Medical Applications of Collagen and Hyaluronan in Regenerative Medicine.

In order to develop and commercialize for the regenerative medicinal products, smart biomaterials with biocompatibility must be needed. In this chapter, we introduce collagen and hyaluronic acid (HA) as extracellular matrix as well as deal with the molecular mechanism as microenvironment, mechanistic effects, and gene expression. Application of collagen and HA have been reviewed in the area of orthopedics, orthopedics, ophthalmology, dermatology and plastic surgery. Finally, the ongoing and commercial products of collagen and HA for regenerative medicine have been introduced.

Hyaluronan Upregulates Mitochondrial Biogenesis and Reduces Adenoside Triphosphate Production for Efficient Mitochondrial Function in Slow-Proliferating Human Mesenchymal Stem Cells.

Hyaluronan-coated surfaces preserve the proliferation and differentiation potential of mesenchymal stem cells by prolonging their G1-phase transit, which maintains cells in a slow-proliferative mode. Mitochondria are known to play a crucial role in stem cell self-renewal and differentiation. In this study, for the first time, the metabolic mechanism underlying the hyaluronan-regulated slow-proliferative maintenance of stem cells was investigated by evaluating mitochondrial functions. Human placenta-derived mesenchymal stem cells (PDMSCs) cultured on hyaluronan-coated surfaces at 0.5, 3.0, 5.0, and 30 µg/cm2 were found to have an average 58% higher mitochondrial mass and an increase in mitochondrial DNA copy number compared to noncoated tissue culture surfaces (control), as well as a threefold increase in the gene expression of the mitochondrial biogenesis-related gene PGC-1α. Increase in mitochondrial biogenesis led to a hyaluronan dose-dependent increase in mitochondrial membrane potential, ATP content, and oxygen consumption rate, with reactive oxygen species levels shown to be at least three times lower compared to the control. Although hyaluronan seemed to favor mitochondrial function, cell entry into a hyaluronan-regulated slow-proliferative mode led to a fivefold reduction in ATP production and coupling efficiency levels. Together, these results suggest that hyaluronan-coated surfaces influence the metabolic proliferative state of stem cells by upregulating mitochondrial biogenesis and function with controlled ATP production. This more efficiently meets the energy requirements of slow-proliferating PDMSCs. A clear understanding of the metabolic mechanism induced by hyaluronan in stem cells will allow future applications that may overcome the current limitations faced in stem cell culture. Stem Cells 2016;34:2512-2524.

Short- and long-term use of medication for psychological distress after the diagnosis of cancer.

PURPOSE: This study investigated the short- and long-term use of medication for psychological distress after the diagnosis of cancer. METHODS: Longitudinal data from the Taiwan National Health Insurance database were used to follow 35,137 cancer patients for 2.5 years after being diagnosed in 2006 and 2007. RESULTS: Among those patients who survived for at least 180 days, 20.9 % had used psychotropic medications; sedatives were the most frequently prescribed (14.3 %), followed by antidepressants (5.5 %), anxiolytics (3.6 %), and antipsychotics (2.7 %). Lung cancer, prostate cancer, and oral cancer showed a significant association with the regular use of medication in the first 180 days. Among patients who survived for at least 2.5 years, 4.8 % still used psychotropic medication on a regular basis. Lung cancer and prostate cancer were associated with such prolonged use. CONCLUSIONS: This longitudinal study found that the type of cancer was significantly associated with the use of psychotropic drugs after the diagnosis was made. It provided information about the trajectory of that use and found that a small number of patients were still using those medications after 2.5 years.

Pathogenic Acanthamoeba castellanii Secretes the Extracellular Aminopeptidase M20/M25/M40 Family Protein to Target Cells for Phagocytosis by Disruption.

Acanthamoeba is free-living protist pathogen capable of causing a blinding keratitis and granulomatous encephalitis. However, the mechanisms of Acanthamoeba pathogenesis are still not clear. Here, our results show that cells co-cultured with pathogenic Acanthamoeba would be spherical and floated, even without contacting the protists. Then, the Acanthamoeba protists would contact and engulf these cells. In order to clarify the contact-independent pathogenesis mechanism in Acanthamoeba, we collected the Acanthamoeba-secreted proteins (Asp) to incubate with cells for identifying the extracellular virulent factors and investigating the cytotoxicity process. The Asps of pathogenic Acanthamoeba express protease activity to reactive Leu amino acid in ECM and induce cell-losing adhesion ability. The M20/M25/M40 superfamily aminopeptidase protein (ACA1_264610), an aminopeptidase be found in Asp, is upregulated after Acanthamoeba and C6 cell co-culturing for 6 h. Pre-treating the Asp with leucine aminopeptidase inhibitor and the specific antibodies of Acanthamoeba M20/M25/M40 superfamily aminopeptidase could reduce the cell damage during Asp and cell co-incubation. These results suggest an important functional role of the Acanthamoeba secreted extracellular aminopeptidases in the Acanthamoeba pathogenesis process. This study provides information regarding clinically pathogenic isolates to target specific molecules and design combined drugs.

Evaluation of cellular retinoic acid binding protein 2 gene expression through the retinoic acid pathway by co-incubation of Blastocystis ST-1 with HT29 cells in vitro.

Blastocystis is a parasitic protist with a worldwide distribution that is commonly found in patients with colon and gastrointestinal pathological symptoms. Blastocystis infection has also commonly been reported in colorectal cancer and HIV/AIDS patients with gastrointestinal symptoms. To understand the pathway networks of gene regulation and the probable mechanisms influencing functions of HT-29 host cells in response to parasite infection, we examined the expression of 163 human oncogenes and kinases in human colon adenocarcinoma HT-29 cells co-incubated with Blastocystis by in-house cDNA microarray and PCR analysis. At least 10 genes were shown to be modified following Blastocystis co-incubation, including those with immunological, tumorigenesis, and antitumorigenesis functions. The expression of genes encoding cellular retinoic acid binding protein 2 (CRABP2) and proliferating cell nuclear antigen (PCNA) was markedly upregulated and downregulated, respectively. Reverse transcriptase-PCR validated the modified transcript expression of CRABP2 and other associated genes such as retinoic acid (RA)-related nuclear-receptor (RARα). Together, our data indicate that CRABP2, RARα, and PCNA expressions are involved in RA signaling regulatory networks that affect the growth, proliferation, and inflammation of HT-29 cells.

Leptin of dermal adipose tissue is differentially expressed during the hair cycle and contributes to adipocyte-mediated growth inhibition of anagen-phase vibrissa hair.

Adipose tissue encircles the lower portion of anagen hair follicles and may regulate hair cycle progression. As leptin is a major adipokine, its level of expression from the dermal white adipose tissue during hair cycle progression was studied. The result shows that leptin level is differentially expressed during hair cycle, the lowest in early anagen phase, upregulated in late anagen phase and the highest in the telogen phase. On the other hand, leptin receptor is detected in keratin 15-positive hair bulge epithelium of both anagen- and telogen-phase hair follicles of mice pelage and vibrissa hair, and hair from human scalp. Leptin contributes to adipocyte-mediated growth inhibition of anagen-phase vibrissa hair as demonstrated in organ culture and coculture system. Our data suggest that leptin of dermal white adipose tissue might regulate hair growth and, therefore, hair cycle progression via leptin receptor on the hair follicle epithelium.

Ocular syphilis in patients with Human Immunodeficiency Virus infection.

As Acquired Immunodeficiency Disease (AIDS) turns thirty-years old, much progress has been made. 56,000 new cases of the Human Immunodeficiency Virus (HIV) infection are expected in Americans this year. At least half or more will be in African Americans. Reports of the association between syphilis and HIV infection are well documented. We present a case of bilateral optic neuritis and panuveitis as the initial presentation in a previously undiagnosed patient with human immunodeficiency virus (HIV) and syphilis.

National Trends in Interventions for Pediatric Gallstone Pancreatitis.

Introduction: Laparoscopic cholecystectomy (LC) during index hospitalization for gallstone pancreatitis is standard in adult populations. The objective of this study was to evaluate trends in use of LC and endoscopic retrograde cholangiopancreatography (ERCP) for children with gallstone pancreatitis. Materials and Methods: This retrospective cohort study used the Kids' Inpatient Database, spanning 2000-2019, to identify patients aged 18 years or younger with a principal diagnosis of gallstone pancreatitis. The Mann-Kendall trend test was used to assess trends over time. Results: Gallstone pancreatitis occurred in 5028 patients. The rate of LC during index hospitalization ranged from 55.4% to 63.8% (P = .76). Trends demonstrate that LC occurred on average hospital day 4.6 in 2000 and decreased to 3.4 in 2019 (P < .01). Among those undergoing LC, average length of stay (LOS) decreased from 6.8 days in 2000 to 5.1 days in 2019 (P < .01). The rate of ERCP alone decreased from 24.8% in 2000 to 14.0% in 2019 (P = .23). For those undergoing ERCP, average hospital day of ERCP decreased from 3.3 in 2000 to 2.3 in 2019 (P = .07). The rate of undergoing both an ERCP and LC decreased from 19.0% in 2000 to 8.5% in 2019 (P = .13). For patients who underwent either LC or ERCP, average LOS decreased from 7.0 days in 2000 to 5.1 days in 2019 (P < .01). For patients who did not undergo a procedure, average LOS decreased from 5.7 days in 2000 to 4.0 days in 2019 (P = .13). Conclusion: The proportion of LC performed during index hospitalizations for children with gallstone pancreatitis has been stable for two decades. However, trends indicate that interventions are occurring earlier, and LOS is becoming shorter.

Can you know before you go? Information about disability accommodations on US hospital websites.

BACKGROUND: People with disability (PWD) face challenges accessing healthcare. Websites are a public-facing resource that can help PWD determine if a hospital can accommodate their needs, yet few studies have described whether hospital websites contain adequate accommodation information. OBJECTIVE: To characterize the extent to which information about disability accommodations is available on US hospital websites. METHODS: We manually reviewed hospital websites using a structured extraction form. We used the Centers for Medicare and Medicaid Services' Hospital General Information Data set to identify a stratified random sample of 600 nonspecialty hospitals in the United States. We excluded hospitals that shared a website with a previously reviewed hospital for a final sample of 445. We recorded (1) content about specific disability accommodations (in 11 predetermined categories); (2) descriptions of hospital policy mentioning disability; and (3) the point of contact to obtain more information about accommodations. RESULTS: About two-thirds (65.6%) of sampled hospitals were acute care hospitals (vs 34.4% critical access); 53.5% had 26-299 beds. Overall, 73.7% websites had information about accommodations; of these, 36.3% had information solely within hospital policies. Of the 47.0% websites with accommodation information beyond hospital policies, the mean number of accommodations listed (excluding policy statements) was 2.37 (of 11 possible). Hospitals with 300+ beds had higher odds of listing any nonpolicy accommodations than those with 1-26 beds (odds ratio = 2.768, p = .02). Less than half (40.5%) hospitals listed a contact person. CONCLUSIONS: Information about disability accommodations is sparse on hospital websites. Comprehensive and actionable communication about accommodations is needed to better protect PWD's rights to accessible healthcare.

Malnutrition in hospitalized adults in the United States, 2016-2019.

BACKGROUND: Malnutrition in hospitalized patients is associated increased length of stay, cost, readmission, and death. No recent studies have examined trends in prevalence or outcomes of hospitalized patients with a diagnosis of malnutrition. OBJECTIVES: To study the prevalence of malnutrition diagnostic codes and associated hospital outcomes in the United States between 2016 and 2019. METHODS: We conducted a retrospective trends study to identify use of malnutrition codes in hospitalizations in the National Inpatient Sample between 2016 and 2019. We used direct standardization by logistic regression to adjust outcomes of percutaneous gastrostomy tube placement, mechanical ventilation, and death for age, Gagne comorbidity score, and sex. We then used linear regression to test for trends over time by malnutrition type. RESULTS: Across all hospitalizations, codes for diagnoses of non-severe malnutrition and severe malnutrition were present in 3.7% and 4.1% of hospitalizations, respectively. Codes for any malnutrition increased over time, from 6.6% in 2016 to 8.6% in 2018 (p = .03). Codes for severe malnutrition increased from 3.3% to 4.7% (p = .01). Among hospitalizations with coded severe malnutrition diagnoses, there was a statistically significant decrease in adjusted rate of death over time (-0.54% per year, p = .03) which was not seen in hospitalizations without coded malnutrition diagnoses. CONCLUSIONS: Use of malnutrition diagnosis codes increased significantly from 2016 to 2019. During this time, mortality among hospitalizations with a diagnosis code for severe malnutrition decreased. Though the increased prevalence of malnutrition codes may represent a change in the clinical characteristics of hospitalized patients, the decline in mortality suggests some of the increase may be due to lower threshold for coding and assignment of the diagnosis to less ill patients.

Association Between Common Empiric Antibiotic Regimens and Clostridioides Difficile Infection in Pediatric Appendicitis.

BACKGROUND: Clostridioides Difficile Infection (CDI) is a serious antibiotic related complication that has been reported among children undergoing treatment of appendicitis. CDI likelihood amongst different empiric antibiotic regimens for appendicitis remains unclear but likely has important implications for antibiotic stewardship. METHODS: A retrospective cohort study of the Pediatric Health Information System was used to examine patients ages 1 through 18 who received operative management of acute appendicitis. Common empiric antibiotic regimens 1) Ceftriaxone & Metronidazole (CM) 2) Piperacillin & Tazobactam (PT) and 3) Cefoxitin were compared. Study outcomes were CDI within 28 days post-appendectomy and 30-day post-appendectomy percutaneous drainage procedures. Subset analyses were repeated to only include hospitals that standardized empiric antibiotic choice. RESULTS: Of 105,911 patients, 220 (0.21 %) developed CDI. CDI was more common in patients that received CM (CM 0.29 % vs PT 0.15 % vs Cefoxitin 0.18 %; P < 0.01). On adjusted analysis, PT was associated with a lower likelihood of CDI (OR, 0.48; 95%CI, 0.31-0.74) compared to CM which was consistent in hospitals with standardized antibiotic choice. Exposure to more unique antibiotic regimens (OR, 1.70; 95 % CI, 1.50-1.93) and higher total antibiotic days (OR, 1.17; 95 % CI 1.13-1.21) were associated with an increased likelihood of CDI. There was no significant difference in the likelihood of post-appendectomy percutaneous drainage between antibiotic regimens. CONCLUSIONS: CDI is rare following appendectomy for pediatric appendicitis. While PT was associated with statistically lower rates of CDI compared to CM, antibiotic stewardship efforts to avoid mixed regimens and decrease overall antibiotic exposure warrant exploration. LEVEL OF EVIDENCE: Level III.

The Cost-Effectiveness of Computer-Assisted Compared with Conventional Total Knee Arthroplasty: A Payer's Perspective.

BACKGROUND: Recent evidence showing that computer-assisted total knee arthroplasty (TKA) is associated with better outcomes compared with conventional TKA for patients with end-stage knee osteoarthritis has not been included in economic evaluations of computer-assisted TKA, which are needed to support coverage decisions. This study evaluated the cost-effectiveness of computer-assisted TKA from a payer's perspective, incorporating recent evidence. METHODS: We compared computer-assisted TKA with conventional TKA with regard to costs (in 2022 U.S. dollars) and quality-adjusted life-years (QALYs) using Markov models for elderly patients (≥65 years of age) and patients who were not elderly (55 to 64 years of age). Costs and QALYs were estimated in the lifetime for elderly patients and in the short term for patients who were not elderly, under a bundled payment program and a Fee-for-Service program. Transition probabilities, costs, and QALYs were retrieved from the literature, a national knee arthroplasty registry, and the National Center for Health Statistics. Threshold and probabilistic sensitivity analyses were conducted to examine the robustness of key estimates used in the base-case analysis. Using projected estimates of TKA utilization, the total cost savings of performing computer-assisted TKA rather than conventional TKA were estimated. RESULTS: Compared with conventional TKA, computer-assisted TKA was associated with higher QALYs and lower costs for both elderly patients and patients who were not elderly, regardless of payment programs, making computer-assisted TKA a favorable treatment option. Widespread adoption of computer-assisted TKA in all U.S. patients would result in an estimated total cost saving of $1 billion for payers. CONCLUSIONS: Compared with conventional TKA, computer-assisted TKA reduces costs to payers while providing favorable outcomes. Payers may consider providing additional payment incentives to providers for performing computer-assisted TKA, to achieve outcome improvement and cost control by facilitating widespread adoption of computer-assisted TKA. LEVEL OF EVIDENCE: Economic and Decision Analysis Level II. See Instructions for Authors for a complete description of levels of evidence.

Differential regulation of adherens junction dynamics during apical-basal polarization.

Adherens junctions (AJs) in epithelial cells are constantly turning over to modulate adhesion properties under various physiological and developmental contexts, but how such AJ dynamics are regulated during the apical-basal polarization of primary epithelia remains unclear. Here, we used new and genetically validated GFP markers of Drosophila E-cadherin (DE-cadherin, hereafter referred to as DE-Cad) and ß-catenin (Armadillo, Arm) to quantitatively assay the in vivo dynamics of biosynthetic turnover and membrane redistribution by fluorescence recovery after photobleaching (FRAP) assays. Our data showed that membrane DE-Cad and Arm in AJs of polarizing epithelial cells had much faster biosynthetic turnover than in polarized cells. Fast biosynthetic turnover of membrane DE-Cad is independent of actin- and dynamin-based trafficking, but is microtubule-dependent. Furthermore, Arm in AJs of polarizing cells showed a faster and diffusion-based membrane redistribution that was both quantitatively and qualitatively different from the slower and exchange-based DE-Cad membrane distribution, indicating that the association of Arm with DE-Cad is more dynamic in polarizing cells, and only becomes stable in polarized epithelial cells. Consistently, biochemical assays showed that the binding of Arm to DE-Cad is weaker in polarizing cells than in polarized cells. Our data revealed that the molecular interaction between DE-Cad and Arm is modulated during apical-basal polarization, suggesting a new mechanism that might be crucial for establishing apical-basal polarity through regulating the AJ dynamics.

Transplantation of porcine embryonic stem cells and their derived neuronal progenitors in a spinal cord injury rat model.

BACKGROUND AIMS: The purpose of this study was to investigate therapeutic potential of green fluorescent protein expressing porcine embryonic stem (pES/GFP(+)) cells in A rat model of spinal cord injury (SCI). METHODS: Undifferentiated pES/GFP(+) cells and their neuronal differentiation derivatives were transplanted into the contused spinal cord of the Long Evans rat, and in situ development of the cells was determined by using a live animal fluorescence optical imaging system every 15 days. After pES/GFP(+) cell transplantation, the behavior functional recovery of the SCI rats was assessed with the Basso, Beattie, and Bresnahan Locomotor Rating Scale (BBB scale), and the growth and differentiation of the grafted pES/GFP(+) cells in the SCI rats were analyzed by immunohistochemical staining. RESULTS: The relative green fluorescent protein expression level was decreased for 3 months after transplantation. The pES/GFP(+)-derived cells positively stained with neural specific antibodies of anti-NFL, anti-MBP, anti-SYP and anti-Tuj 1 were detected at the transplanted position. The SCI rats grafted with the D18 neuronal progenitors showed a significant functional recovery of hindlimbs and exhibited the highest BBB scale score of 15.20 ± 1.43 at week 24. The SCI rats treated with pES/GFP(+)-derived neural progenitors demonstrated a better functional recovery. CONCLUSIONS: Transplantation of porcine embryonic stem (pES)-derived D18 neuronal progenitors has treatment potential for SCI, and functional behavior improvement of grafted pES-derived cells in SCI model rats suggests the potential for further application of pES cells in the study of replacement medicine and functionally degenerative pathologies.

Uncovering the common factors of chemical exposure and behavior: Evaluating behavioral effects across a testing battery using factor analysis.

Although specific environmental chemical exposures, including flame retardants, are known risk factors for neurodevelopmental disorders (NDDs), direct experimental evidence linking specific chemicals to NDDs is limited. Studies focusing on the mechanisms by which the social processing systems are vulnerable to chemical exposure are underrepresented in the literature, even though social impairments are defining characteristics of many NDDs. We have repeatedly demonstrated that exposure to Firemaster 550 (FM 550), a prevalent flame retardant mixture used in foam-based furniture and infant products, can adversely impact a variety of behavioral endpoints. Our recent work in prairie voles (Microtus ochrogaster), a prosocial animal model, demonstrated that perinatal exposure to FM 550 sex specifically impacts socioemotional behavior. Here, we utilized a factor analysis approach on a battery of behavioral data from our prior study to extract underlying factors that potentially explain patterns within the FM 550 behavior data. This approach identified which aspects of the behavioral battery are most robust and informative, an outcome critical for future study designs. Pearson's correlation identified behavioral endpoints associated with distance and stranger interactions that were highly correlated across 5 behavioral tests. Using these behavioral endpoints, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) extracted 2 factors that could explain the data: Activity (distance traveled endpoints) and Sociability (time spent with a novel conspecific). Exposure to FM 550 significantly decreased Activity and decreased Sociability. This factor analysis approach to behavioral data offers the advantages of modeling numerous measured variables and simplifying the data set by presenting the data in terms of common, overarching factors in terms of behavioral function.