Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Más filtros

Base de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
J Pediatr Gastroenterol Nutr ; 77(6): 741-747, 2023 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-37755879

RESUMEN

OBJECTIVES: Previous studies have shown increasing hospitalizations for pediatric cholelithiasis, but recent trends are unknown. We conducted a national study of pediatric cholelithiasis to characterize recent hospitalization rate trends. METHODS: Retrospective repeated cross-sectional analysis of pediatric (age < 18 years) cholelithiasis-associated hospitalizations combining data from the 2006 through 2019 Kids' Inpatient Database releases. The primary outcome of interest was the national hospitalization rate (per 100,000 children). We examined rates stratified by age group and sex and characterized hospitalization outcomes and characteristics for pediatric cholelithiasis. RESULTS: Twenty-nine thousand one hundred two hospital records representing 42,282 gallstone-associated hospitalizations were identified. The hospitalization rate declined from 12.9 [95% confidence interval (CI): 12.6-13.2] in 2006 to 9.1 (95% CI: 8.8-9.3) in 2019. Consistent with the literature, hospitalizations occurred most often among teenagers (71%) and individuals with female sex (72%). The proportion of hospitalizations at freestanding children's hospitals increased significantly (from 18.2% to 35.1%). Finally, the proportion of hospitalizations involving a potentially medical predisposing condition increased significantly. CONCLUSIONS: The estimated US hospitalization rate for pediatric cholelithiasis declined by 30% between 2006 and 2019. Female patients and teenagers had the largest decline, and hospitalizations increasingly occurred at freestanding children's hospitals. Potential explanations include potential changes in delivery of care as well as changes in population disease burden.


Asunto(s)
Cálculos Biliares , Hospitalización , Adolescente , Niño , Humanos , Femenino , Estados Unidos/epidemiología , Lactante , Estudios Retrospectivos , Estudios Transversales , Hospitales Pediátricos
2.
JAMA Pediatr ; 177(5): 536-539, 2023 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-36912853

RESUMEN

This cross-sectional study sought to quantify the frequency of change in race category in the electronic medical record (EMR) of a pediatric population.


Asunto(s)
Registros Electrónicos de Salud , Grupos Raciales , Niño , Humanos , Grupos Raciales/clasificación
3.
Pediatr Blood Cancer ; 69(11): e29863, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35997530

RESUMEN

BACKGROUND: Children with sickle cell disease (SCD) have an increased risk for gallstones due to chronic hyperbilirubinemia from hemolysis. Although gallstones are a known complication, there is variability in estimates of disease burden and uncertainty in the association between sex and gall bladder disease (GBD). METHODS: This was a retrospective cohort study of children with SCD using administrative claims data (January 1, 2014-December 31, 2018). Population-averaged multivariable panel-data logistic regression models were used to evaluate the association between GBD clinical encounters (outcome) and two exposures (age and sex). Annual GBD risk was calculated using predictive margins, adjusting for disease severity, transfusion frequency, and hydroxyurea exposure. RESULTS: A total of 13,745 individuals (of 21,487 possible) met inclusion criteria. The population was evenly split across sex (49.5% female) with predominantly Medicaid insurance (69%). A total of 946 individuals (6.9%) had GBD, 432 (3.1%) had a gallstone complication, and 487 (3.5%) underwent cholecystectomy. The annual risk of GBD rose nonlinearly from 1 to 5% between ages 1 and 19 years with no difference between males and females. Cholecystectomy occurred primarily in individuals with GBD (87%), and neither age nor sex was associated with cholecystectomy in this population. High disease severity (compared with low) more than doubled the annual risk of GBD at all ages. CONCLUSIONS: GBD is associated with age but not sex in children with SCD. Neither age nor sex is associated with risk of cholecystectomy. High disease severity increases the rate of GBD at all ages.


Asunto(s)
Anemia de Células Falciformes , Enfermedades de la Vesícula Biliar , Cálculos Biliares , Adolescente , Adulto , Anemia de Células Falciformes/complicaciones , Anemia de Células Falciformes/epidemiología , Niño , Preescolar , Femenino , Enfermedades de la Vesícula Biliar/complicaciones , Enfermedades de la Vesícula Biliar/epidemiología , Cálculos Biliares/complicaciones , Cálculos Biliares/epidemiología , Humanos , Hidroxiurea , Lactante , Masculino , Estudios Retrospectivos , Adulto Joven
4.
J Pediatr Gastroenterol Nutr ; 75(3): 334-339, 2022 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-35653435

RESUMEN

OBJECTIVES: To review the clinical management and outcomes of magnet ingestions at a large tertiary children's hospital. To determine the association of frequency of high-powered magnet ingestion with the regulation of these magnets. METHODS: Children <18 years who presented to the emergency room and were admitted to the Children's Hospital of Philadelphia for ingestion of single or multiple magnets from January 2008 to December 2020 were included. Demographics, symptoms, management, and outcomes were analyzed. The frequency of magnet ingestion was compared over 3 eras: (1) pre-ban (2008-2012), (2) intra-ban (2013-2016), and (3) post-ban (2017-2020). RESULTS: There were 167 magnet ingestions, including 99 with multiple magnets. Most patients (59%) were male and median age was 6 (interquartile range, 3-9) years. Most single magnet ingestions (86%) were discharged with outpatient monitoring, and none experienced severe outcomes. Multiple magnet ingestions led to significant morbidity including hospitalizations (68%), endoscopic procedures (48%), surgical procedures (14%), and severe outcomes (12%). Most patients (75%) were asymptomatic, however, there was a higher risk of surgery and severe complications based on the presence of symptoms ( P = 0.003). The rate of surgical intervention was higher with ≥3 magnets (31.7%) compared to 2 magnets (2.4%) ( P < 0.003). Additionally, we found an 160% increase in children with magnet ingestions in the post-ban period ( P = 0.021). CONCLUSIONS: Multiple magnet ingestion is associated with high morbidity and rate of severe outcomes. There is a relationship between public policy of magnet sale and frequency of magnet ingestion.


Asunto(s)
Cuerpos Extraños , Imanes , Niño , Preescolar , Ingestión de Alimentos , Femenino , Cuerpos Extraños/complicaciones , Hospitales Pediátricos , Humanos , Imanes/efectos adversos , Masculino , Estudios Retrospectivos , Atención Terciaria de Salud
6.
Artículo en Inglés | MEDLINE | ID: mdl-33668103

RESUMEN

This paper describes follow-up for a cohort of 4530 residents living in the asbestos manufacturing community of Ambler, PA, U.S. in 1930. Using re-identified census data, cause and date of death data obtained from the genealogic website Ancestry.com, along with geospatial analysis, we explored relationships among demographic characteristics, occupational, paraoccupational and environmental asbestos exposures. We identified death data for 2430/4530 individuals. Exposure differed significantly according to race, gender, age, and recency of immigration to the U.S. Notably, there was a significant difference in the availability of year of death information for non-white vs. white individuals (odds ratio (OR) = 0.62 p-value < 0.001), females (OR = 0.53, p-value < 0.001), first-generation immigrants (OR = 0.67, p-value = 0.001), second-generation immigrants (OR = 0.31, p-value < 0.001) vs. non-immigrants, individuals aged less than 20 (OR = 0.31 p-value < 0.001) and individuals aged 20 to 59 (OR = 0.63, p-value < 0.001) vs. older individuals. Similarly, the cause of death was less often available for non-white individuals (OR = 0.42, p-value <0.001), first-generation immigrants and (OR = 0.71, p-value = 0.009), second-generation immigrants (OR = 0.49, p-value < 0.001), individuals aged less than 20 (OR = 0.028 p-value < 0.001), and individuals aged 20 to 59 (OR = 0.26, p-value < 0.001). These results identified ascertainment bias that is important to consider in analyses that investigate occupational, para-occupational and environmental asbestos exposure as risk factors for mortality in this historic cohort. While this study attempts to describe methods for assessing itemized asbestos exposure profiles for a community in 1930 using Ancestry.com and other publicly accessible databases, it also highlights how historic cohort studies likely underestimate the impact of asbestos exposure on vulnerable populations. Future work will aim to assess mortality patterns in this cohort.


Asunto(s)
Amianto , Neoplasias Pulmonares , Mesotelioma , Exposición Profesional , Adulto , Anciano , Estudios de Cohortes , Exposición a Riesgos Ambientales , Femenino , Humanos , Persona de Mediana Edad , Adulto Joven
7.
J Pediatr ; 226: 274-277.e1, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32702427

RESUMEN

We conducted a descriptive time-series study of pediatric emergency healthcare use during the onset of severe acute respiratory syndrome coronavirus 2 pandemic after a state-wide stay-at-home order. Our study demonstrated decreased volume, increased acuity, and generally consistent chief complaints compared with the prior 3 years (2017 through 2019). Ingestions became a significantly more common chief complaint in 2020.


Asunto(s)
COVID-19/prevención & control , Servicio de Urgencia en Hospital/tendencias , Utilización de Instalaciones y Servicios/tendencias , Hospitales Pediátricos/tendencias , Aceptación de la Atención de Salud/estadística & datos numéricos , Distanciamiento Físico , Adolescente , Niño , Preescolar , Estudios Transversales , Femenino , Hospitales Urbanos/tendencias , Humanos , Lactante , Recién Nacido , Análisis de Series de Tiempo Interrumpido , Masculino , Factores Protectores , Factores de Riesgo , Índice de Severidad de la Enfermedad , Centros de Atención Terciaria/tendencias , Índices de Gravedad del Trauma , Heridas y Lesiones/diagnóstico , Heridas y Lesiones/epidemiología , Heridas y Lesiones/etiología , Heridas y Lesiones/terapia , Adulto Joven
8.
Acad Pediatr ; 20(3): 364-373, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31108236

RESUMEN

OBJECTIVE: Human papillomavirus (HPV) vaccine has been recommended for male patients for the prevention of genital warts and precancerous anal lesions since 2009. Our objective was to characterize race and insurance-based disparities in HPV vaccine completion among male patients who initiated the HPV vaccine series. METHODS: This was a retrospective cohort study of adolescent male patients in a primary care network who initiated the HPV vaccine series from October 2009 to December 2013. We measured vaccine series completion as the primary outcome. We evaluated associations between outcomes and race and insurance status, controlling for potential confounders and effect modification with multivariable logistic regression. Analyses were stratified by vaccine recommendation era (permissive vs routine). RESULTS: In total, 42% of males in the cohort (16,691) completed the vaccine series. In the permissive vaccine era (2009-2011), non-black patients (53%) were more likely to complete than black patients (32%) and non-Medicaid patients (49%) were more likely to complete than Medicaid patients (33%). These differences persisted in the routine recommendation era (2012-2013). In both the permissive and routine eras, Medicaid insurance was associated with a larger reduction in the predicted probability of vaccine series completion for non-black patients. Adherence to the recommended vaccination schedule was low, with a median time to completion of 8.9 months. Using the updated completion schedule (2016), we found that completion rates were greater (54.1%) with continued differences based on race (60% vs 45.7% for non-black vs black patients) and insurance (57.4% vs 46.4% completion for non-Medicaid vs Medicaid patients). CONCLUSIONS: We found significant disparities in HPV vaccine series completion rates among male patients based on race and insurance, unchanged based on era of initiation or visit frequency.


Asunto(s)
Disparidades en Atención de Salud/estadística & datos numéricos , Seguro de Salud/estadística & datos numéricos , Medicaid/estadística & datos numéricos , Vacunas contra Papillomavirus/uso terapéutico , Aceptación de la Atención de Salud/estadística & datos numéricos , Población Blanca/estadística & datos numéricos , Adolescente , Conducta del Adolescente , Negro o Afroamericano/estadística & datos numéricos , Niño , Estudios de Cohortes , Disparidades en Atención de Salud/etnología , Humanos , Masculino , Aceptación de la Atención de Salud/etnología , Estudios Retrospectivos , Estados Unidos , Wisconsin
9.
J Natl Med Assoc ; 111(6): 665-673, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31668360

RESUMEN

BACKGROUND: Physician diversity is linked to improved quality of care of diverse patient populations. The transition from medical school to residency is an opportunity to improve and increase workforce diversity in all specialties. However, there is limited published literature on the factors contributing to the ranking of residency programs on women and underrepresented minorities (URMs). OBJECTIVE: To characterize factors medical students used to rank residency programs and describe any differences based on race/ethnicity or gender. METHODS: A mixed-methods study consisting of a web-based survey and semi-structured interviews with National Resident Matching Program (NRMP) participating graduates over a two-year period. The survey assessed demographics and a 6-point Likert scale rating of various factors used to rank residency programs. Unpaired student t-tests were used to compare means. A subset of students was interviewed and a modified grounded theory approach identified decision-making themes as well as the role of gender and URM status. RESULTS: Out of a total of 316 invitations sent, 148 completed the survey (46.8% response rate), of which 21% of respondents self-identified as URMs. The majority of respondents graduated in 2014 (53%), and were male (51%). Participants ranked program atmosphere, reputation, location, and proximity to family the highest. URM students ranked patient population (p < 0.01), revisit opportunities (p = 0.04), gender diversity (p < 0.01), and ethnic diversity (p < 0.01) significantly higher than non-URM students. Female students ranked patient population (p < 0.01) and gender diversity (p < 0.01) significantly higher than males. Qualitative findings revealed differences in perceptions by URMs and non-URMs of patient population, revisit opportunities, gender diversity, and ethnic diversity. CONCLUSIONS: While all students prioritized pragmatic factors, women and URM students assess and weigh additional factors related to culture, inclusion, and diversity more than others. By tailoring recruitment strategies to meet the expectations of women and URMs, residency programs can better meet goals in becoming more diverse and inclusive.


Asunto(s)
Conducta de Elección , Internado y Residencia , Grupos Minoritarios , Factores Sexuales , Estudiantes de Medicina/estadística & datos numéricos , Femenino , Humanos , Entrevistas como Asunto , Masculino , Encuestas y Cuestionarios , Estados Unidos
11.
BMC Pediatr ; 19(1): 72, 2019 03 08.
Artículo en Inglés | MEDLINE | ID: mdl-30849955

RESUMEN

BACKGROUND: Total parenteral nutrition (TPN) and biliary atresia (BA) are common causes of cholestasis in infancy. The diagnosis of BA is time sensitive due to an inverse correlation between age at intervention (hepatic portoenterostomy - HPE) and survival without liver transplantation. Clinical, laboratory, and histologic features of BA and parenteral nutrition associated cholestasis (PNAC) are similar, creating a diagnostic dilemma for cholestatic infants on parenteral nutrition. There is limited published information about the natural history of PNAC including time to resolution, or diagnostic tests that distinguish BA from other etiologies of cholestasis. CASE PRESENTATION: We present a case of a child diagnosed with BA whose cholestasis began while receiving TPN. His clinical course was notable for transient resolution of his cholestasis after stopping parenteral nutrition and ultimate intraoperative diagnosis. CONCLUSIONS: Clinicians who care for patients who frequently receive TPN should be aware that clinical, laboratory, imaging, and biopsy findings can be similar between BA and PNAC.


Asunto(s)
Atresia Biliar/diagnóstico , Hígado/patología , Nutrición Parenteral Total/efectos adversos , Atresia Biliar/complicaciones , Bilirrubina/sangre , Colestasis/etiología , Diagnóstico Diferencial , Humanos , Hiperbilirrubinemia/etiología , Lactante , Masculino
12.
Front Pediatr ; 6: 173, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29974044

RESUMEN

Background: Eosinophilic esophagitis is a chronic, immune-mediated disease characterized by symptoms of esophageal dysfunction and ≥15 eosinophils/high-powered field (eos/hpf). Proton pump inhibitor responsive esophageal eosinophilia (1) is an entity of esophageal eosinophilia that responds to PPI therapy and is thought to be clinically and histologically similar to EoE. Current guidelines suggest therapy with PPI prior to endoscopy and use of PPI as first line for esophageal eosinophilia. In order to gain a better understanding of community practice patterns and to try differentiate between these two entities, we sought to evaluate the clinical presentations, treatment and final diagnoses of patients presenting to our institution for second opinions of esophageal eosinophilia. Methods: A search of our electronic medical record yielded a list of patients presenting for a second opinion of esophageal eosinophilia. Charts were reviewed for clinical information. Results: A total of 187 charts were included. Patients ranged from 1-19 years old with 75% being male and 74% being Caucasian. Of the patients who had documentation of their medications at the time of initial endoscopy, 70% were not on any PPI prior to their endoscopy, and 94% were on <2 mg/kg/day. Of the 19 patients who had full response to PPI therapy and were diagnosed with PPI-REE, close to half had previously been treated with diet, steroids, or both. Patients with final diagnosis of EoE had significantly higher eos/hpf on initial endoscopy compared to those with diagnosis of PPI-REE (51.9 ± 30.6 v. 35.8 ± 16.4. p = 0.027), as well as higher likelihood of having IgE-mediated food allergy (79 v. 47%, p = 0.003). Conclusions: Diagnostic and therapeutic algorithms are needed for esophageal eosinophilia to prevent misdiagnosis and unnecessary procedures and therapies.

13.
Adv Radiat Oncol ; 1(4): 325-332, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-28740904

RESUMEN

PURPOSE: There is growing evidence supporting incorporating multiparametric (mp) magnetic resonance imaging (MRI) scans into risk stratification, active surveillance, and treatment paradigms for prostate cancer. The purpose of our study was to determine whether demographic disparities exist in staging MRI utilization for prostate cancer patients. METHODS AND MATERIALS: An institutional database of 705 nonmetastatic prostate cancer patients treated with radiation therapy from 2005 through 2013 was used to identify patients undergoing versus not undergoing pretreatment diagnostic prostate mpMRI. Uni- and multivariable logistic regression evaluated the relationship of clinical and demographic characteristics with MRI utilization. RESULTS: All demographic variables assessed, except the other race category, were significantly associated with MRI utilization (all P < .05), including age (odds ratio [OR], 0.92), black race (OR, 0.51), poverty (OR, 0.53), closer distance to radiation facility (OR, 1.79), and nonprivate primary insurance (OR, 0.57) on univariable analysis, while clinical stage T3 (OR, 3.37) was the only clinical characteristic. On multivariable analysis stratified by D'Amico risk group, age remained significant across all risk groups, whereas the black versus white racial (OR, 0.21; 95% confidence interval, 0.08-0.55) and nonprivate versus private insurance type (OR, 0.37; 95% confidence interval, 0.16-0.86) disparities persisted in the low-risk group. Clinical stage T3 remained associated in the high-risk group. For race specifically, the percentages of whites, blacks, and others undergoing MRI in the overall cohort and by risk group were, respectively: overall, 80% (343/427), 68% (156/231), and 85% (40/47); low risk, 86%, 56%, and 63%; intermediate risk, 79%, 72%, and 95%; and high risk, 72%, 72%, and 100%. CONCLUSIONS: In this urban, academic center cohort, older patients across all risk groups and black or nonprivate insurance patients in the low risk group were less likely to undergo staging prostate MRI scans. Further research should investigate these differences to ensure equitable utilization across all demographic groups considering the burden of prostate cancer disparities.

14.
J Adolesc Health ; 57(5): 506-14, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26381919

RESUMEN

PURPOSE: The purpose of this study was to describe patterns of human papillomavirus (HPV) vaccine initiation by males and characterize sociodemographic differences. METHODS: We conducted a retrospective cohort study of 11- to 18-year-old males in a large primary care network who had a preventive or acute visit between October 2009 and December 2013. Outcomes measured were HPV vaccine series initiation and initiation at the first eligible visit. Logistic regression measured independent associations between outcomes and sociodemographic characteristics, adjusting for potential confounders including visit frequency, insurance changes, and the presence of complex medical conditions. RESULTS: Of 58,757 eligible patients, most were white (57%) with private insurance (77%). During the study period, 39% of the cohort initiated the vaccine series, and 7% initiated at their first eligible visit. Black patients with private (adjusted odds ratio [aOR], 1.99; 95% confidence interval [CI], 1.73-2.30) and Medicaid insurance (aOR, 2.90; 95% CI, 2.56-3.30) had significantly higher odds of HPV vaccine initiation compared with white patients with private insurance. A similar trend was found for Hispanic patients with private (aOR, 1.45; 95% CI, 1.26-1.67) and Medicaid insurance (aOR, 2.15; 95% CI, 1.78-2.60). These differences were present both in the preroutine recommendation period (2009-2011) and the postroutine recommendation period (2012-2013). CONCLUSIONS: Traditionally marginalized populations have higher odds of HPV vaccine initiation, both at the first eligible visit and overall. Although the true mechanism underlying these differences remains unknown, potential candidates include provider recommendation patterns and differential vaccine acceptance within these groups.


Asunto(s)
Infecciones por Papillomavirus/prevención & control , Vacunas contra Papillomavirus , Vacunación/estadística & datos numéricos , Adolescente , Niño , Humanos , Modelos Logísticos , Masculino , Infecciones por Papillomavirus/etnología , Atención Primaria de Salud/estadística & datos numéricos , Estudios Retrospectivos , Factores Socioeconómicos , Estados Unidos
16.
Nat Mater ; 11(10): 895-905, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22797827

RESUMEN

The tumour microenvironment thwarts conventional immunotherapy through multiple immunologic mechanisms, such as the secretion of the transforming growth factor-ß (TGF-ß), which stunts local tumour immune responses. Therefore, high doses of interleukin-2 (IL-2), a conventional cytokine for metastatic melanoma, induces only limited responses. To overcome the immunoinhibitory nature of the tumour microenvironment, we developed nanoscale liposomal polymeric gels (nanolipogels; nLGs) of drug-complexed cyclodextrins and cytokine-encapsulating biodegradable polymers that can deliver small hydrophobic molecular inhibitors and water-soluble protein cytokines in a sustained fashion to the tumour microenvironment. nLGs releasing TGF-ß inhibitor and IL-2 significantly delayed tumour growth, increased survival of tumour-bearing mice, and increased the activity of natural killer cells and of intratumoral-activated CD8(+) T-cell infiltration. We demonstrate that the efficacy of nLGs in tumour immunotherapy results from a crucial mechanism involving activation of both innate and adaptive immune responses.


Asunto(s)
Antineoplásicos/administración & dosificación , Inmunoterapia/métodos , Interleucina-2/administración & dosificación , Nanoestructuras , Neoplasias Experimentales/terapia , Factor de Crecimiento Transformador beta/antagonistas & inhibidores , Inmunidad Adaptativa , Animales , Antineoplásicos/farmacología , Ciclodextrinas , Composición de Medicamentos , Geles , Inmunidad Innata , Interleucina-2/farmacología , Células Asesinas Naturales/metabolismo , Liposomas , Ratones , Ratones Endogámicos , Neoplasias Experimentales/inmunología , Linfocitos T/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Microambiente Tumoral/efectos de los fármacos
17.
Acta Biomater ; 8(1): 124-32, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21911086

RESUMEN

There are limited options for surgeons to repair simple or complex tissue defects due to injury, illness or disease. Consequently, there are few treatments for many serious ailments, including neural-related injuries, myocardial infarction and focal hyaline cartilage defects. Tissue-engineered scaffolds offer great promise for addressing these wide-ranging indications; however, there are many considerations that need to be made when conceptualizing a product. For many applications, an in situ forming scaffold that could completely fill defects with complex geometries, adhere to adjacent tissues and foster cell proliferation would be ideal. Additionally, the scaffold would preferably have tailored mechanical properties similar to native tissues and highly controllable gelation kinetics, and would not require an external trigger, such as ultraviolet light, for gelation. We have developed a unique injectable hydrogel system composed of collagen and multi-armed poly(ethylene glycol) (PEG) that meets all of these criteria. The collagen component enables cellular adhesion and permits enzymatic degradation, while the multi-armed PEG component has amine-reactive chemistry that also binds proteins/tissue and is hydrolytically degradable. We have characterized the mechanical properties, swelling, degradation rates and cytocompatibility of these novel hydrogels. The hydrogels demonstrated tunable mechanics, variable swelling and suitable degradation profiles. Cells adhered and proliferated to near confluence on the hydrogels over 7 days. These data suggest that these collagen and PEG hydrogels exhibit the mechanical, physical and biological properties suitable for use as an injectable tissue scaffold for the treatment of a variety of simple and complex tissue defects.


Asunto(s)
Colágeno/química , Hidrogeles/química , Polietilenglicoles/química , Regeneración , Andamios del Tejido/química , Animales , Materiales Biocompatibles/química , Línea Celular , Fuerza Compresiva , Elasticidad , Fibroblastos/citología , Fibroblastos/fisiología , Ensayo de Materiales , Porcinos , Ingeniería de Tejidos/instrumentación , Ingeniería de Tejidos/métodos
18.
J Control Release ; 156(1): 109-15, 2011 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-21723893

RESUMEN

Biodegradable polymeric nanoparticles are widely recognized as efficacious drug delivery vehicles, yet the rational engineering of nanoparticle surfaces in order to improve biodistribution, reduce clearance, and/or improve targeting remains a significant challenge. We have previously demonstrated that an amphiphilic conjugate of avidin and palmitic acid can be used to modify poly(lactic-co-glycolic acid) (PLGA) particle surfaces to display functional avidin groups, allowing for the facile attachment of biotinylated ligands for targeting or steric stabilization. Here, we hypothesized that the incorporation, density, and stability of surface-presented avidin could be modulated through varying the lipophilicity of its fatty acid conjugate partner. We tested this hypothesis by generating a set of novel conjugates incorporating avidin and common fatty acids. We found that conjugation to linoleic acid resulted in a ~60% increase in the incorporation of avidin on the nanoparticle surface compared to avidin-palmitic acid, which exhibited the highest avidin incorporation in previous studies. Further, the linoleic acid-avidin conjugate yielded nanoparticles with enhanced ability to bind biotinylated ligands compared to the previous method; nanoparticles modified with avidin-linoleic acid bound ~170% more biotin-HRP than those made with avidin-palmitic acid and ~1300% more than particles made without conjugated avidin. Most critically, increased ligand density on anti-CD4-targeted nanoparticles formulated with the linoleic acid-avidin conjugate resulted in a 5% increase in binding of CD4(+) T cells. Thus we conclude that the novel avidin-linoleic acid conjugate facilitates enhanced ligand density on PLGA nanoparticles, resulting in functional enhancement of cellular targeting.


Asunto(s)
Materiales Biocompatibles/química , Portadores de Fármacos/química , Ácido Láctico/química , Nanopartículas/química , Ácido Poliglicólico/química , Tensoactivos/química , Animales , Avidina/química , Linfocitos T CD4-Positivos/efectos de los fármacos , Células Cultivadas , Estabilidad de Medicamentos , Fluoresceína-5-Isotiocianato/administración & dosificación , Fluoresceína-5-Isotiocianato/análogos & derivados , Fluoresceína-5-Isotiocianato/química , Fluoresceína-5-Isotiocianato/farmacología , Ligandos , Ratones , Microscopía Electrónica de Rastreo , Ácido Palmítico/química , Tamaño de la Partícula , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Albúmina Sérica Bovina/administración & dosificación , Albúmina Sérica Bovina/química , Albúmina Sérica Bovina/farmacología , Bazo/citología , Bazo/efectos de los fármacos , Propiedades de Superficie
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA