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Clinical Outcomes After Tracheostomy in Children With Single Ventricle Physiology: Collaborative Research From the Pediatric Cardiac Intensive Care Society Multicenter Cohort, 2010-2021. Pediatr Crit Care Med 2024:00130478-990000000-00339. [PMID: 38683049 DOI: 10.1097/pcc.0000000000003523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
OBJECTIVES Multicenter studies reporting outcomes following tracheostomy in children with congenital heart disease are limited, particularly in patients with single ventricle physiology. We aimed to describe clinical characteristics and outcomes in a multicenter cohort of patients with single ventricle physiology who underwent tracheostomy before Fontan operation. DESIGN Multicenter retrospective cohort study.SETTING: Twenty-one tertiary care pediatric institutions participating in the Collaborative Research from the Pediatric Cardiac Intensive Care Society. PATIENTS We reviewed 99 children with single ventricle physiology who underwent tracheostomy before the Fontan operation at 21 institutions participating in Collaborative Research from the Pediatric Cardiac Intensive Care Society between January 2010 and December 2020, with follow-up through December 31, 2021. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Death occurred in 51 of 99 patients (52%). Cox proportional hazard analysis was performed to determine factors associated with death after tracheostomy. Results are presented as hazard ratio (HR) with 95% CIs. Nonrespiratory indication(s) for tracheostomy (HR, 2.21; 95% CI, 1.14-4.32) and number of weeks receiving mechanical ventilation before tracheostomy (HR, 1.06; 95% CI, 1.02-1.11) were independently associated with greater hazard of death. In contrast, diagnosis of tricuspid atresia or Ebstein's anomaly was associated with less hazard of death (HR, 0.16; 95% CI, 0.04-0.69). Favorable outcome, defined as survival to Fontan operation or decannulation while awaiting Fontan operation with viable cardiopulmonary physiology, occurred in 29 of 99 patients (29%). Median duration of mechanical ventilation before tracheostomy was shorter in patients who survived to favorable outcome (6.1 vs. 12.1 wk; p < 0.001), and only one of 16 patients with neurologic indications for tracheostomy and 0 of ten patients with cardiac indications for tracheostomy survived to favorable outcome. CONCLUSIONS For children with single ventricle physiology who undergo tracheostomy, mortality risk is high and should be carefully considered when discussing tracheostomy as an option for these children. Favorable outcomes are possible, although thoughtful attention to patient selection and tracheostomy timing are likely necessary to achieve this goal.
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Pulmonary Atresia with Intact Ventricular Septum: Midterm Outcomes from a Multicenter Cohort. Pediatr Cardiol 2024; 45:847-857. [PMID: 35751685 DOI: 10.1007/s00246-022-02954-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/08/2022] [Indexed: 11/28/2022]
Abstract
Contemporary multicenter data regarding midterm outcomes for neonates with pulmonary atresia with intact ventricular septum are lacking. We sought to describe outcomes in a contemporary multicenter cohort, determine factors associated with end-states, and evaluate the effect of right ventricular coronary dependency and coronary atresia on transplant-free survival. Neonates treated during 2009-2019 in 19 United States centers were reviewed. Competing risks analysis was performed to determine cumulative risk of each end-state, and multivariable regression analyses were performed to identify factors associated with each end-state and transplant-free survival. We reviewed 295 patients. Median tricuspid valve Z-score was - 3.06 (25%, 75%: - 4.00, - 1.52). Final end-state was biventricular repair for 45 patients (15.2%), one-and-a half ventricle for 16 (5.4%), Fontan for 75 (25.4%), cardiac transplantation for 29 (9.8%), and death for 54 (18.3%). Seventy-six patients (25.7%) remained in mixed circulation. Cumulative risk estimate of death was 10.9%, 16.1%, 16.9%, and 18.8% at 1, 6 months, 1 year, and 5 years, respectively. Tricuspid valve Z-score was inversely, and coronary atresia positively associated with death or transplantation [odds ratio (OR) = 0.46, (95% confidence interval (CI) = 0.29-0.75, p < 0.001) and OR = 3.75 (95% CI 1.46-9.61, p = 0.011), respectively]. Right ventricular coronary dependency and left coronary atresia had a significant effect on transplant-free survival (log-rank p < 0.001). In a contemporary multicenter cohort of patients with PAIVS, consisting predominantly of patients with moderate-to-severe right ventricular hypoplasia, we observed favorable survival outcomes. Right ventricular coronary dependency and left, but not right, coronary atresia significantly worsens transplant-free survival.
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The 'Holy Grail' of shoulder dislocations: a systematic review on traumatic bilateral luxatio erecta; is it in reality a once-in-a-lifetime experience for an orthopaedic surgeon? Arch Orthop Trauma Surg 2024; 144:205-217. [PMID: 37776337 PMCID: PMC10774214 DOI: 10.1007/s00402-023-05047-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 08/26/2023] [Indexed: 10/02/2023]
Abstract
INTRODUCTION Even though shoulder dislocation is thought to be the most common dislocation treated in the Emergency Department, inferior ones, known as Luxatio Erecta, comprise only 0.5% of them. Taking into consideration the rareness of unilateral Luxatio Erecta, bilateral cases should be even fewer. The purpose of this paper is to identify the reported number of cases of Traumatic Bilateral Luxatio Erecta in the literature over the last 100 years and to summarize the mechanism of injury, the initial management, and the complications of these patients. MATERIALS AND METHODS We performed a systematic review of the literature regarding Traumatic Bilateral Luxatio Erecta. All articles published until 31st of December 2022 in PubMed and Google Scholar databases were searched using the terms "luxatio erecta", 'inferior dislocation", and "bilateral". RESULTS Eighty-two articles were retrieved from PubMed and Google Scholar search. Forty-four of them were initially included in our review. Six additional articles meeting the inclusion criteria were found from cross-references. CONCLUSION The presence of this injury is extremely rare with only 51 cases in the literature. The incidence of concomitant injuries and complications seems to be extremely high and neurological deficits were detected on 42.8% of patients with Bilateral Luxatio Erecta. To our knowledge, this is the first systematic review of the literature regarding Traumatic Bilateral Luxatio Erecta that includes articles not only in English, a fact that provides more reliability on the estimation of the real number of cases of this rare injury compared to any other review on this subject to date.
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Static Baropodometry for Assessing Short-Term Functional Outcome after Unilateral Total Knee Arthroplasty: Exploring Correlation between Static Plantar Pressure Measurements and Self-Reported Outcomes. J Clin Med 2023; 12:6917. [PMID: 37959381 PMCID: PMC10650917 DOI: 10.3390/jcm12216917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/15/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023] Open
Abstract
This study aimed to investigate the association between objective baropodometric and radiological measurements and patient self-reported functional outcomes, assessed through the Knee Injury and Osteoarthritis Outcome Score (KOOS). Additionally, it sought to evaluate the effectiveness of static baropodometry in predicting short-term KOOS results following unilateral total knee arthroplasty (TKA). We conducted a prospective single-center study involving 32 patients who underwent unilateral TKA for knee osteoarthritis (KOA). Patients were evaluated both preoperatively and six months postoperatively, utilizing objective measurements derived from static baropodometric analysis in a normal, relaxed, bipedal standing position using a multi-platform Plantar Pressure Analysis System (PPAS) and radiographic measurements of the femorotibial angle (FTA) and subjective assessments through the national validated version of the KOOS. The study found an insignificant average correction of -0.69° ± 4.12° in the preoperative FTA at the sixth month after TKA. Moreover, there were no significant differences in the KOOS based on different types of knee alignment (KA) both pre- and postoperatively (p > 0.05). No significant correlations were observed between the KOOS, and total average affected and unaffected plantar pressures (TAAPP and TAUPP) pre- and postoperatively, as well as KA pre- and postoperatively. However, significant changes were observed in TAAPP and TAUPP measurements after unilateral TKA. TAAPP demonstrated a significant increase postoperatively (mean change (SD) = 18.60 (47.71); p = 0.035). In conclusion, this study found no significant correlation between KA, static baropodometric measurements, including pre- and postoperative differences, and KOOS outcomes. Therefore, static plantar pressure measurements alone might not serve as a reliable predictor of short-term clinical outcomes after unilateral TKA, as reported by patients.
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Implementation of a 24-hour infection diagnosis protocol in the pediatric cardiac intensive care unit (CICU). Infect Control Hosp Epidemiol 2023; 44:1300-1307. [PMID: 36382469 DOI: 10.1017/ice.2022.265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To reduce unnecessary antibiotic exposure in a pediatric cardiac intensive care unit (CICU). DESIGN Single-center, quality improvement initiative. Monthly antibiotic utilization rates were compared between 12-month baseline and 18-month intervention periods. SETTING A 25-bed pediatric CICU. PATIENTS Clinically stable patients undergoing infection diagnosis were included. Patients with immunodeficiency, mechanical circulatory support, open sternum, and recent culture-positive infection were excluded. INTERVENTIONS The key drivers for improvement were standardizing the infection diagnosis process, order-set creation, limitation of initial antibiotic prescription to 24 hours, discouraging indiscriminate vancomycin use, and improving bedside communication and situational awareness regarding the infection diagnosis protocol. RESULTS In total, 109 patients received the protocol; antibiotics were discontinued in 24 hours in 72 cases (66%). The most common reasons for continuing antibiotics beyond 24 hours were positive culture (n = 13) and provider preference (n = 13). A statistical process control analysis showed only a trend in monthly mean antibiotic utilization rate in the intervention period compared to the baseline period: 32.6% (SD, 6.1%) antibiotic utilization rate during the intervention period versus 36.6% (SD, 5.4%) during the baseline period (mean difference, 4%; 95% CI, -0.5% to -8.5%; P = .07). However, a special-cause variation represented a 26% reduction in mean monthly vancomycin use during the intervention period. In the patients who had antibiotics discontinued at 24 hours, delayed culture positivity was rare. CONCLUSIONS Implementation of a protocol limiting empiric antibiotic courses to 24 hours in clinically stable, standard-risk, pediatric CICU patients with negative cultures is feasible. This practice appears safe and may reduce harm by decreasing unnecessary antibiotic exposure.
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Atrial arrhythmias following lung transplant: a single pediatric center experience. Front Pediatr 2023; 11:1161129. [PMID: 37425256 PMCID: PMC10326625 DOI: 10.3389/fped.2023.1161129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/15/2023] [Indexed: 07/11/2023] Open
Abstract
Background Outcomes after lung transplant (LTx) in children have slowly improved. Although atrial arrhythmia (AA) is a common and adverse complication following LTx among adults, there is limited data on pediatric recipients. We detail our pediatric single-center experience while providing further insights on occurrence and management of AA following LTx. Methods A retrospective analysis of LTx recipients at a pediatric LTx program from 2014 to 2022 was performed. We investigated timing of occurrence and management of AA following LTx, and its effect on post-LTx outcome. Results Three out of nineteen (15%) pediatric LTx recipients developed AA. The timing of occurrence was 9-10 days following LTx. Those patients in the older age group (age >12 years old) were the only ones who developed AA. Developing AA did not have a negative effect on hospital stay duration or short-term mortality. All LTx recipients with AA were discharged home on therapy that was discontinued at 6 months for those who was on mono-therapy without recurrence of AA. Conclusions AA is an early post-operative complication in older children and younger adults undergoing LTx at a pediatric center. Early recognition and aggressive management can mitigate any morbidity or mortality. Future investigations should explore factors that place this population at risk for AA in order to prevent this complication post-operatively.
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Abstract
OBJECTIVES Near-infrared spectroscopy (NIRS) has been increasingly accepted as a noninvasive marker of regional tissue oxygenation despite concerns of imprecision and wide limits of agreement (LOA) with invasive oximetry. New generation absolute monitors may have improved accuracy compared with trend monitors. We sought to compare the concordance with invasive venous oximetry of a new generation absolute NIRS-oximeter (FORESIGHT ELITE; CASMED, Branford, CT) with a modern widely used trend monitor (INVOS 5100C; Medtronic, Minneapolis, MN). DESIGN Prospective single-center study. SETTING Tertiary pediatric heart center. PATIENTS Children undergoing elective cardiac catheterization under general anesthesia. Time-paired venous oximetry samples (jugular and renal) were compared with NIRS-derived oximetry by two monitors using regression and Bland-Altman analysis. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS We enrolled 36 children (19 female, 10 cyanotic) with median age 4.1 years (25-75%, 2.5-7.8 yr) and weight 16.7 kg (12.3-29.1 kg). The absolute difference between NIRS-derived and invasive jugular oximetry was less than 10% in 67% of occasions for both monitors. Correlation was fair (Spearman rs = 0.40; p = 0.001) for the FORESIGHT ELITE and poor ( rs = 0.06; p = 0.71) for the INVOS 5100C. Bias and LOA were +6.7% (+22%, -9%) versus +1.3% (LOA = +24%, -21%), respectively. The absolute difference between NIRS-derived and invasive renal oximetry was less than 10% in 80% of occasions with moderate correlation ( rs = 0.57; p < 0.001) for the FORESIGHT ELITE and in 61% of occasions with moderate correlation ( rs = 0.58; p < 0.001) for the INVOS 5100C; bias and LOA were +3.6% (+19%, -12%) and -1.4 % (+27%, -30%), respectively. NIRS correlation with renal venous oximetry was worse for cyanotic versus noncyanotic patients ( p = 0.02). CONCLUSIONS Concordance and LOA of NIRS-derived oximetry with invasive venous oximetry in the cerebral and renal vascular beds was suboptimal for clinical decision-making. Cyanosis adversely affected NIRS performance in the renal site.
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Contemporary Multicenter Outcomes for Truncus Arteriosus With Interrupted Aortic Arch. Ann Thorac Surg 2023; 115:144-150. [PMID: 36084696 DOI: 10.1016/j.athoracsur.2022.08.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 08/01/2022] [Accepted: 08/08/2022] [Indexed: 12/31/2022]
Abstract
BACKGROUND Truncus arteriosus with interrupted aortic arch (TA-IAA) is a rare congenital heart defect with historically poor outcomes. Contemporary multicenter data are limited. METHODS A retrospective cohort study of children who underwent repair of TA-IAA between 2009 and 2016 at 12 tertiary care referral centers within the United States was performed. Major adverse cardiac events (MACE) were defined as postoperative extracorporeal membrane oxygenation, cardiopulmonary resuscitation, or operative mortality. TA-IAA patients were compared with TA patients who underwent repair during the study period from the same institutions. RESULTS We reviewed 35 patients with TA-IAA. MACE occurred in 12 patients (34%). Improvement over time was observed during the study period with 11 events (92%) occurring in the first half of the study period (P = .03). Factors associated with MACE included moderate or severe truncal valve insufficiency (P < .01), concomitant truncal valve repair (P = .04), and longer cardiopulmonary bypass duration (P = .02). In comparison with 216 patients who underwent TA repair, patients with TA-IAA had a higher rate of MACE, but this finding was not statistically significant (34% vs 20%, respectively; P = .07). Additionally no differences between TA-IAA and TA groups were observed for unplanned reoperations (14% vs 22%, respectively; P = .3), hospital length of stay (24 vs 23 days, P = .65), or late deaths (7% vs 7%, P = 1.00). CONCLUSIONS In this contemporary, multicenter cohort the rate of MACE after repair of TA-IAA was high but improved during the study period. Early childhood outcomes of patients with TA-IAA were similar to those with TA.
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Procedural Outcomes of Pulmonary Atresia Intact Ventricular Septum in Neonates: A Multicenter Study. Ann Thorac Surg 2022; 115:1470-1477. [PMID: 36070807 DOI: 10.1016/j.athoracsur.2022.07.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 06/10/2022] [Accepted: 07/19/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Multicenter contemporary data describing short-term outcomes following initial interventions of neonates with pulmonary atresia intact ventricular septum (PA-IVS) are limited. This multicenter study aims to describe characteristics and outcomes of PA-IVS neonates following their initial catheter or surgical intervention and identify factors associated with major adverse cardiac events (MACE). METHODS Neonates with PA-IVS who underwent surgical or catheter intervention between 2009-2019 in 19 centers were reviewed. Risk factors for MACE, defined as cardiopulmonary resuscitation, mechanical circulatory support, stroke, or in-hospital mortality, were analyzed using multivariable logistic regression model. RESULTS We reviewed 279 neonates: 79 (28%) underwent right ventricular decompression, 151 (54%) underwent systemic-to-pulmonary shunt or ductal stent placement only, 36 (13%) underwent right ventricular decompression with shunt or ductal stent placement, and 11 (4%) underwent transplantation. MACE occurred in 57 patients (20%): 26 (9%) received mechanical circulatory support, 37 (13%) received cardiopulmonary resuscitation, 16 (6%) suffered stroke, 23 (8%) died. The presence of two major coronary artery stenoses (adjusted OR: 4.99; 95% CI: 1.16-21.39) and lower weight at first intervention (adjusted OR: 1.52, 95% CI: 1.01-2.27) were significantly associated with MACE. Coronary ischemia was the most frequent presumed mechanism of death (n=10). CONCLUSIONS In a multicenter cohort, one in five neonates with PA-IVS experienced MACE following their initial intervention. Patients with two major coronary artery stenoses or lower weight at time of initial procedure were most likely to experience MACE and warrant vigilance during pre-intervention planning and post-intervention management.
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Anomalous Origin of the Left Coronary Artery From the Pulmonary Artery: A Retrospective Multicenter Study. Pediatr Crit Care Med 2021; 22:e626-e635. [PMID: 34432672 DOI: 10.1097/pcc.0000000000002820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We aimed to describe characteristics and operative outcomes from a multicenter cohort of infants who underwent repair of anomalous left coronary artery from the pulmonary artery. We also aimed to identify factors associated with major adverse cardiovascular events following anomalous left coronary artery from the pulmonary artery repair. DESIGN Retrospective chart review. SETTING Twenty-one tertiary-care referral centers. PATIENTS Infants less than 365 days old who underwent anomalous left coronary artery from the pulmonary artery repair. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Major adverse cardiovascular events were defined as the occurrence of postoperative extracorporeal membrane oxygenation, cardiopulmonary resuscitation, left ventricular assist device, heart transplantation, or operative mortality. Factors independently associated with major adverse cardiovascular events were identified using multivariable logistic regression analysis. We reviewed 177 infants (< 365 d old) who underwent anomalous left coronary artery from the pulmonary artery repair between January 2009 and March 2018. Major adverse cardiovascular events occurred in 36 patients (20%). Twenty-nine patients (16%) received extracorporeal membrane oxygenation, 14 (8%) received cardiopulmonary resuscitation, four (2%) underwent left ventricular assist device placement, two (1%) underwent heart transplantation, and six (3.4%) suffered operative mortality. In multivariable analysis, preoperative inotropic support (odds ratio, 3.5; 95% CI, 1.4-8.5), cardiopulmonary bypass duration greater than 150 minutes (odds ratio, 6.9 min; 95% CI, 2.9-16.7 min), and preoperative creatinine greater than 0.3 mg/dL (odds ratio, 2.4 mg/dL; 95% CI, 1.1-5.6 mg/dL) were independently associated with major adverse cardiovascular events. In patients with preoperative left ventricular end-diastolic diameter measurements available (n = 116), left ventricular end-diastolic diameter z score greater than 6 was also independently associated with major adverse cardiovascular events (odds ratio, 7.6; 95% CI, 2.0-28.6). CONCLUSIONS In this contemporary multicenter analysis, one in five children who underwent surgical repair of anomalous left coronary artery from the pulmonary artery experienced major adverse cardiovascular events. Preoperative characteristics such as inotropic support, creatinine, and left ventricular end-diastolic diameter z score should be considered when planning for potential postoperative complications.
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Abstract
We describe the successful treatment of a 10-month-old female with respiratory distress secondary to Coronavirus disease 2019 (COVID-19) with the nebulized investigational drug, DAS181. Therapy was well tolerated, and the patient had minimal side effects. The patient's respiratory distress and positive viral polymerase chain reaction rapidly resolved after initiation of therapy.
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Lithographically Defined Cross-Linkable Top Coats for Nanomanufacturing with High-χ Block Copolymers. ACS APPLIED MATERIALS & INTERFACES 2021; 13:11224-11236. [PMID: 33621463 DOI: 10.1021/acsami.1c00694] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The directed self-assembly (DSA) of block copolymers (BCPs) is a powerful method for the manufacture of high-resolution features. Critical issues remain to be addressed for successful implementation of DSA, such as dewetting and controlled orientation of BCP domains through physicochemical manipulations at the BCP interfaces, and the spatial positioning and registration of the BCP features. Here, we introduce novel top-coat (TC) materials designed to undergo cross-linking reactions triggered by thermal or photoactivation processes. The cross-linked TC layer with adjusted composition induces a mechanical confinement of the BCP layer, suppressing its dewetting while promoting perpendicular orientation of BCP domains. The selection of areas of interest with perpendicular features is performed directly on the patternable TC layer via a lithography step and leverages attractive integration pathways for the generation of locally controlled BCP patterns and nanostructured BCP multilayers.
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Characteristics and Surgical Outcomes of Patients With Late Presentation of Anomalous Left Coronary Artery From the Pulmonary Artery: A Multicenter Study. Semin Thorac Cardiovasc Surg 2020; 33:141-150. [PMID: 32858217 DOI: 10.1053/j.semtcvs.2020.08.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 08/20/2020] [Indexed: 11/11/2022]
Abstract
We sought to describe the clinical course and outcomes of patients who are diagnosed with anomalous left coronary artery from the pulmonary artery (ALCAPA) after infancy. We conducted a retrospective evaluation of patients who underwent ALCAPA surgery between January 2009 to March 2018 at 21 US centers. Clinical presentation, inpatient management, and postoperative outcomes of patients repaired ≥1 year of age were described. To characterize this cohort, we compared these data to patients repaired before 1 year of age. Of 248 ALCAPA patients, 71 (29%) underwent repair ≥1 year of age. Among this subset, the median age at diagnosis was 8.3 years. Chronic arrhythmia occurred in 7%. Patients had good postoperative recovery of left ventricle (LV) dysfunction (90%) and LV dilation (75%), although a low incidence of recovery of mitral regurgitation (40%). Compared to infants, older patients were more likely to present with cardiac arrest (11% vs 1%) and less likely to have moderate or worse LV dysfunction or mitral regurgitation. Older patients had significantly less postoperative extracorporeal membrane oxygenation use, and shorter ICU and hospital stay. In the older cohort, operative mortality occurred in only 1 patient and no patient died after discharge (median follow-up 2.7 years). Survival of patients who presented with ALCAPA beyond infancy was excellent, although chronic mitral regurgitation and chronic arrhythmia were not uncommon. Patients who underwent ALCAPA repair ≥1 year of age were less likely to present with LV dysfunction but more likely to present with cardiac arrest than younger patients.
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Glucocorticoid Receptor Polymorphisms in Children Undergoing Congenital Heart Surgery with Cardiopulmonary Bypass. J Pediatr Intensive Care 2020; 9:241-247. [PMID: 33133738 DOI: 10.1055/s-0040-1709658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/10/2020] [Indexed: 10/24/2022] Open
Abstract
We conducted a candidate gene association study to test the hypothesis that different gene polymorphisms will be associated with corticosteroid responsiveness and study outcomes among children undergoing congenital heart surgery. This is a prospective observational cohort study at a large, tertiary pediatric cardiac center on children undergoing corrective or palliative congenital heart surgery. A total of 83 children were enrolled. DNA was isolated for three polymorphisms of interest namely N363 (rs56149945) and 9β (rs6198) associated with increased sensitivity to corticosteroids and Bcl I (rs41423247) associated with decreased sensitivity to corticosteroids. Duration of inotropic use, low cardiac output scores (LCOS), and vasoactive inotrope scores were examined in relation to these three polymorphisms. Using Kaplan-Meier analysis, heterozygous individuals showed longer transcriptional intermediary factor (TIF) compared with wild type for N363 polymorphism ( p = 0.05). In multivariable Cox regression, heterozygous alleles for 9β polymorphism showed significantly shorter TIF compared with wild type (hazard ratio = 2.04 [1.08-3.87], p = 0.03). The relationship between lower LCOS scores and alleles groups was significant for 9β heterozygous polymorphism only (1.5 [1-2.2], p = 0.01) in comparison to wild type and homozygous. The presence of heterozygote alleles for the increased corticosteroid sensitivity is associated with longer TIF compared with wild type. Conversely, the presence of heterozygous alleles for the decreased sensitivity to corticosteroids is associated with shorter TIF compared with wild type.
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Utilization of inhaled nitric oxide after surgical repair of truncus arteriosus: A multicenter analysis. CONGENIT HEART DIS 2019; 14:1078-1086. [PMID: 31713327 DOI: 10.1111/chd.12849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/14/2019] [Accepted: 09/11/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Elevated pulmonary vascular resistance (PVR) is common following repair of truncus arteriosus. Inhaled nitric oxide (iNO) is an effective yet costly therapy that is frequently implemented postoperatively to manage elevated PVR. OBJECTIVES We aimed to describe practice patterns of iNO use in a multicenter cohort of patients who underwent repair of truncus arteriosus, a lesion in which recovery is often complicated by elevated PVR. We also sought to identify patient and center factors that were more commonly associated with the use of iNO in the postoperative period. DESIGN Retrospective cohort study. SETTING 15 tertiary care pediatric referral centers. PATIENTS All infants who underwent definitive repair of truncus arteriosus without aortic arch obstruction between 2009 and 2016. INTERVENTIONS Descriptive statistics were used to demonstrate practice patterns of iNO use. Bivariate comparisons of characteristics of patients who did and did not receive iNO were performed, followed by multivariable mixed logistic regression analysis using backward elimination to identify independent predictors of iNO use. MAIN RESULTS We reviewed 216 patients who met inclusion criteria, of which 102 (46%) received iNO in the postoperative period: 69 (68%) had iNO started in the operating room and 33 (32%) had iNO initiated in the ICU. Median duration of iNO use was 4 days (range: 1-21 days). In multivariable mixed logistic regression analysis, use of deep hypothermic circulatory arrest (odds ratio: 3.2; 95% confidence interval: 1.2, 8.4) and center (analyzed as a random effect, p = .02) were independently associated with iNO use. CONCLUSIONS In this contemporary multicenter study, nearly half of patients who underwent repair of truncus arteriosus received iNO postoperatively. Use of iNO was more dependent on individual center practice rather than patient characteristics. The study suggests a need for collaborative quality initiatives to determine optimal criteria for utilization of this important but expensive therapy.
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Commentary: Thyroid Hormone (T3) Replacement After Congenital Heart Surgery: "I'll Be Back"… But Still Not Work. Semin Thorac Cardiovasc Surg 2019; 32:96-97. [PMID: 31400400 DOI: 10.1053/j.semtcvs.2019.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 08/05/2019] [Indexed: 11/11/2022]
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Simulation Training Improves Resuscitation Team Leadership Skills of Nurse Practitioners. J Pediatr Health Care 2019; 33:280-287. [PMID: 30497891 DOI: 10.1016/j.pedhc.2018.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/11/2018] [Accepted: 09/17/2018] [Indexed: 12/01/2022]
Abstract
INTRODUCTION In the current era of limited physician trainee work hours, limited nurse practitioner orientation times, and highly specialized care settings, frontline providers have limited opportunities for mentored resuscitation training in emergency situations. We aimed to evaluate the effectiveness of a pilot program to improve resuscitation team leadership skills of nurse practitioners using simulation-based training. METHODS Seven nurse practitioners underwent a 4-hour simulation course in pediatric cardiac emergencies. Pre- and post-course surveys were conducted to evaluate previous emergency leadership experience and self-reported comfort in the team lead role. The time to verbalization of a shared mental model to the team was tracked during the simulations. RESULTS The increases in self-reported comfort level in team leading, sharing a mental model, and differential diagnosis were statistically significant. Average time to shared mental model significantly decreased between simulations. DISCUSSION Simulation can improve code leadership skills of nurse practitioners. These preliminary findings require confirmation in larger studies.
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Characteristics and operative outcomes for children undergoing repair of truncus arteriosus: A contemporary multicenter analysis. J Thorac Cardiovasc Surg 2019; 157:2386-2398.e4. [PMID: 30954295 DOI: 10.1016/j.jtcvs.2018.12.115] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 11/20/2018] [Accepted: 12/22/2018] [Indexed: 01/29/2023]
Abstract
OBJECTIVE We sought to describe characteristics and operative outcomes of children who underwent repair of truncus arteriosus and identify risk factors for the occurrence of major adverse cardiac events (MACE) in the immediate postoperative period in a contemporary multicenter cohort. METHODS We conducted a retrospective review of children who underwent repair of truncus arteriosus between 2009 and 2016 at 15 centers within the United States. Patients with associated interrupted or obstructed aortic arch were excluded. MACE was defined as the need for postoperative extracorporeal membrane oxygenation, cardiopulmonary resuscitation, or operative mortality. Risk factors for MACE were identified using multivariable logistic regression analysis and reported as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS We reviewed 216 patients. MACE occurred in 44 patients (20%) and did not vary significantly over time. Twenty-two patients (10%) received postoperative extracorporeal membrane oxygenation, 26 (12%) received cardiopulmonary resuscitation, and 15 (7%) suffered operative mortality. With multivariable logistic regression analysis (which included adjustment for center effect), factors independently associated with MACE were failure to diagnose truncus arteriosus before discharge from the nursery (OR, 3.1; 95% CI, 1.3-7.4), cardiopulmonary bypass duration >150 minutes (OR, 3.5; 95% CI, 1.5-8.5), and right ventricle-to-pulmonary artery conduit diameter >50 mm/m2 (OR, 4.7; 95% CI, 2.0-11.1). CONCLUSIONS In a contemporary multicenter analysis, 20% of children who underwent repair of truncus arteriosus experienced MACE. Early diagnosis, shorter duration of cardiopulmonary bypass, and use of smaller diameter right ventricle-to-pulmonary artery conduits represent potentially modifiable factors that could decrease morbidity and mortality in this fragile patient population.
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Multicenter Analysis of Early Childhood Outcomes After Repair of Truncus Arteriosus. Ann Thorac Surg 2019; 107:553-559. [DOI: 10.1016/j.athoracsur.2018.08.094] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/22/2018] [Accepted: 08/29/2018] [Indexed: 10/28/2022]
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Abstract
OBJECTIVES Postoperative administration of corticosteroids is common practice for managing catecholamine refractory low cardiac output syndrome. Since corticosteroid activity is dependent on the glucocorticoid receptor, we sought to characterize glucocorticoid receptor levels in children undergoing cardiac surgery and examined the association between glucocorticoid receptor levels and cardiovascular dysfunction. DESIGN Prospective observational cohort study. SETTING Large, tertiary pediatric cardiac center. SUBJECTS Children undergoing corrective or palliative cardiac surgery. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS A prospective observational cohort study was conducted in 83 children with congenital heart disease. Total glucocorticoid receptor levels were measured in the peripheral WBCs using flow cytometry. In addition, blood samples were collected for total cortisol levels. The primary outcome studied was the time to being inotrope free. An increase in glucocorticoid receptor level from postoperative day 1 to postoperative day 3 was associated with a longer time to being inotrope free (hazard ratio, 0.49 [0.29-0.81]; p = 0.01) in the univariate analysis. This association remained significant after adjusting for age, weight, cardiopulmonary bypass time, cross clamp time, Risk Adjustment for Congenital Heart Surgery-1 score, and postoperative steroid use (hazard ratio, 0.53 [0.29-0.99]; p = 0.05). Postoperative day 3 glucocorticoid receptor level showed a trend to have longer time to being inotrope free (hazard ratio, 0.66 [0.42-1.02]; p = 0.0.06). The cortisol levels minimally increased during the study duration and did not correlate with glucocorticoid receptor levels. CONCLUSIONS Increasing glucocorticoid receptor levels in peripheral WBCs of children undergoing cardiac surgery are associated with a longer time to being inotrope free. Cortisol levels minimally increased during the study duration. These results suggest that exposure to high-dose perioperative corticosteroids may suppress the hypothalamic-pituitary-adrenal axis leading to increase in glucocorticoid receptor levels in response to a low cortisol environment. Further studies are required to better delineate the interplay between glucocorticoid receptor levels, cortisol levels, corticosteroid exposure, and postoperative inotropic requirements.
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Role of Charge of Micellar Worms in Modulating Structure and Rheological Properties of Their Mixtures with Nonionic Polymer. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b02246] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Irreducible Anterior Shoulder Dislocation with Interposition of the Long Head of the Biceps and Greater Tuberosity Fracture: A Case Report and Review of the Literature. Open Orthop J 2017; 11:327-334. [PMID: 28553421 PMCID: PMC5427706 DOI: 10.2174/1874325001711010327] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 11/22/2022] Open
Abstract
Background: Failure of closed manipulative reduction of an acute anterior shoulder dislocation is seldom reported in the literature and is usually due to structural blocks such as soft tissue entrapment (biceps, subscapularis, labrum), bony fragments (glenoid, greater tuberosity) and severe head impaction (Hill-Sachs lesion). Case report: We present a case of an irreducible anterior shoulder dislocation in a 57-year-old male patient after a road-traffic accident. He had severe impaction of the head underneath glenoid rim and associated fracture of the greater tuberosity. Closed reduction performed in the emergency room under sedation and later at the theatre under general anaesthesia was unsuccessful. Open reduction using the dectopectoral approach revealed that the reason for obstruction was the posterolateral entrapment of the biceps tendon between the humeral head and the tuberosity fragment. Reduction was achieved after subscapularis tenotomy and opening of the joint; the tuberosity fragment was fixed with transosseous sutures and the long head of the biceps tendon was tenodesized. The patient had an uneventful postoperative recovery and at his last follow up, 12 months postoperatively, he had a stable joint, full range of motion and a Constant score of 90. Conclusion: A comprehensive literature review revealed 22 similar reports affecting a total of 30 patients. Interposition of the LHBT alone or in combination with greater tuberosity fracture was the most common obstacle to reduction, followed by subscapularis tendon interposition and other less common reasons. Early surgical intervention with open reduction and confrontation of associated injuries is mandatory for a successful outcome.
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Translation, cultural adaptation, validity and reliability of the Greek version of the modified Constant Score. JSES OPEN ACCESS 2017; 1:45-50. [PMID: 30675539 PMCID: PMC6340836 DOI: 10.1016/j.jses.2017.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aim The purpose of this study was to produce a modified Greek translation of the CS and to test this version in terms of reliability and validity. Materials and methods Translation of the modified Constant score testing protocol was done according to established international guidelines. Sixty-three patients with shoulder pain caused by degenerative or inflammatory disorders completed the Greek version of CS along with the Greek versions of SF-12 and Quick Dash Scores and the ASES Rating Scale and were included into the validation process. To assess test–retest reliability, 58 individuals completed the subjective part of the test again after 24–36 hours, while abstaining from all forms of treatment; internal consistency was measured using Cronbach's alpha (α); reliability was assessed with test–retest procedure and the use of Interclass Correlation Coefficient (ICC), whereas the validity of the reference questionnaire was evaluated using Pearson's correlation coefficient in relation to control questionnaires. Results There were no major problems during the forward–backward translation of the CS into Greek. The internal consistency was high (Cronbach's alpha 0.92) while the test–retest reliability for the overall questionnaire was also high (intra-class coefficient 0.95). Construct validity was confirmed with high values of Pearson's correlation between CS and Q-DASH (0.84), SF-12 (0.80) and ASES score (0.86) in respect. Conclusion A translation and cultural adaptation of CS into Greek was successfully contacted. The Greek version of the modified Constant Score can be a useful modality in the evaluation of shoulder disorders among Greek patients and doctors.
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Viscoelastic Synergy and Microstructure Formation in Aqueous Mixtures of Nonionic Hydrophilic Polymer and Charged Wormlike Surfactant Micelles. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b02385] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Preoperative Intubation and Lack of Enteral Nutrition are Associated with Prolonged Stay After Arterial Switch Operation. Pediatr Cardiol 2016; 37:1078-84. [PMID: 27084382 DOI: 10.1007/s00246-016-1394-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 04/05/2016] [Indexed: 11/29/2022]
Abstract
Mortality for the arterial switch operation (ASO) has diminished significantly over the past few decades. Some patients do, however, continue to have protracted and complicated courses after surgery. We attempted to determine which preoperative factors were best associated with prolonged hospital stay after ASO. We retrospectively reviewed all patients that underwent an ASO over a 10-year period. Outcomes of patients with postoperative stays (POS) >14 days (long stay group-LS) were compared with those patients with POS < 7 days (short stay group-SS). The following variables were evaluated: age at surgery, weight, septostomy performed (BAS) and management the day prior to surgery including use of prostaglandin E1 (PGE1), inotropes, intubation status and the establishment of enteral feeds. The SS group had 25 patients and the LS group had 32 patients. Both groups (SS vs. LS) were similar in PGE1 use (48 vs. 69 %), BAS (76 vs. 59 %), age at surgery (6 vs. 7 days) and preoperative inotropes (12 vs. 38 %). The SS group had significantly higher incidence of preoperative feeding (80 vs. 31 %, p < 0.001) and less frequent intubation (12 vs. 47 %, p < 0.001). Patients who are intubated and have not yet begun to receive enteral feeds at the time of their ASO are more likely to have prolonged POS. It is unclear if prolonged stays were a result of operating on patients with worse preoperative hemodynamics or a consequence of a preoperative management strategy that did not allow for extubation and establishment of feeds prior to surgery.
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Giant Cell Tumor of the Patella Tendon Sheath Presenting as a Painful Locked Knee. AMERICAN JOURNAL OF CASE REPORTS 2015; 16:568-73. [PMID: 26302970 PMCID: PMC4554334 DOI: 10.12659/ajcr.893849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Patient: Male, 26 Final Diagnosis: Giant cell tumor of the patella tendon seath Symptoms: Efusion • locking knee • pain Medication: None Clinical Procedure: Arthroscopy and open resection of the tumor Specialty: Orthopedics and Traumatology
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BioTextQuest+: a knowledge integration platform for literature mining and concept discovery. Bioinformatics 2015; 31:979. [DOI: 10.1093/bioinformatics/btv029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Crosslinking of Epoxidized Natural Rubber by Dicarboxylic Acids: An Alternative to Standard Vulcanization. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/masy.201300053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sequential Association of Anionic/Thermosensitive Diblock Copolymers with Cationic Surfactants. Macromolecules 2013. [DOI: 10.1021/ma302535k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Imidazole-accelerated crosslinking of epoxidized natural rubber by dicarboxylic acids: a mechanistic investigation using NMR spectroscopy. Polym Chem 2012. [DOI: 10.1039/c2py00591c] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Imidazole-promoted acceleration of crosslinking in epoxidized natural rubber/dicarboxylic acid blends. POLYMER 2011. [DOI: 10.1016/j.polymer.2011.09.032] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Formation of hybrid wormlike micelles upon mixing cetyl trimethylammonium bromide with poly(methyl methacrylate-co-sodium styrene sulfonate) copolymers in aqueous solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5054-5061. [PMID: 21446711 DOI: 10.1021/la200017j] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The association of cetyltrimethylammonium bromide, CTAB, with a series of P(MMAx-co-SSNa) random copolymers of sodium styrene sulfonate (SSNa) with methyl methacrylate (MMA) was explored in aqueous solution as a function of the MMA molar content, x, of the copolymers. The polyelectrolyte/surfactant complexation in aqueous solution was verified through pyrene fluorescence probing. In addition, turbidimetry studies in dilute or more concentrated aqueous solutions elucidated the phase separation behavior of the P(MMAx-co-SSNa)/CTAB systems as a function of the copolymer composition x and the surfactant to polyelectrolyte mixing charge ratio. It is found that practically phase separation is completely suppressed within the studied mixing range when the MMA content of the copolymers is ∼30-40 mol%. For lower MMA contents the polyelectrolyte/surfactant complex separates out from water, while for higher x values the solubility limits of the copolymers in water are attained. For the intermediate MMA contents, viscoelastic systems are obtained in more concentrated polymer/surfactant solutions provided that the polyelectrolyte is fully complexed with the cationic surfactant ((1)H NMR results). Moreover, the (1)H NMR studies indicate that hybrid P(MMAx-co-SSNa)/CTAB wormlike micelles are formed in water under these conditions. Finally, it is shown that addition of salt prevents syneresis problems and facilitates the rheological investigation.
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Effect of DMF on the Rheological Properties of Telechelic Polyelectrolyte Hydrogels. Macromolecules 2010. [DOI: 10.1021/ma101238s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Poly(N
,N
-dimethylacrylamide)-block
-Poly(L
-lysine) Hybrid Block Copolymers: Synthesis and Aqueous Solution Characterization. MACROMOL CHEM PHYS 2010. [DOI: 10.1002/macp.200900448] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Insight into people living with type 2 diabetes: a global survey of patients and physicians. Can J Diabetes 2009. [DOI: 10.1016/s1499-2671(09)33207-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Doubly responsive polymer-microgel composites: rheology and structure. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:11474-11482. [PMID: 18781781 DOI: 10.1021/la8018056] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Mixtures of alkali swellable microgels and linear PNIPAm chains exhibit doubly responsive properties both with pH and temperature. Below the lower critical solution temperature (LCST), the linear chains of PNIPAm are soluble and increase the osmotic pressure outside the microgels, which causes them to deswell. Above the LCST, the PNIPAm chains become insoluble and form spherical colloidal particles confined between the microgels that subsequently reswell. The swelling and deswelling of the microgels change the rheological properties of the composites, providing a unique way to tune the elasticity of the composites with temperature. The structure of the composites above the LCST is studied using multiple light scattering and fluorescence confocal microscopy. The phase separation of PNIPAm above the LCST is strongly affected by the confinement of the PNIPAm chains between the microgels.
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Solvent effects on the copolymerization kinetics of ionic (AMPS) and non-ionic (HEAm) acrylamide derivatives. Eur Polym J 2008. [DOI: 10.1016/j.eurpolymj.2008.03.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Kinetics of Demixing and Remixing Transitions in Aqueous Solutions of Poly(N-isopropylacrylamide): A Temperature-Jump1H NMR Study. MACROMOL CHEM PHYS 2006. [DOI: 10.1002/macp.200600394] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Graft Copolymers of Poly(methyl methacrylate) and Polyamide-6: Synthesis by Reactive Blending and Characterization. Macromolecules 2006. [DOI: 10.1021/ma060036x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
It has been shown that proteins encoded by linked genes have similar rates of evolution and that clusters of essential genes are found in regions with low recombination rates. We show here that proteins encoded by linked genes in two closely related bacterial species, namely Escherichia coli K12 and Salmonella typhimurium LT2, evolve more slowly when compared with proteins encoded by genes that are not linked as assessed by protein sequence similarity. The proteins encoded by the identified linked genes share an average sequence identity of 82.5% compared with a 46.5% identity of proteins encoded by genes that are not linked.
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Interpolymer association between hydrophobically modified poly(sodium acrylate) and poly(N-isopropylacrylamide) in water: The role of hydrophobic interactions and polymer structure. Eur Polym J 2006. [DOI: 10.1016/j.eurpolymj.2005.09.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Control of the Chemical Cross-Linking of Gelatin by a Thermosensitive Polymer: Example of Switchable Reactivity. Biomacromolecules 2005; 6:3073-8. [PMID: 16283729 DOI: 10.1021/bm0503928] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chemical cross-linking of gelatin is achieved using a thermosensitive reactive copolymer based on N-isopropylacrylamide (NIPAM). The copolymer bears 5 mol % acrylic acid units which form amide bonds with the amino groups of gelatin in the presence of a water-soluble carbodiimide. The cross-linking reaction occurs only below the LCST congruent with 34 degrees C (lower critical solution temperature), i.e., when the copolymer is in the coil conformation. Above the LCST the copolymer adopts a globule conformation and its ability to react with gelatin is drastically reduced. By setting the temperature above or below the LCST it is possible to switch off or on the reactivity of the system and control the gelation process. The switch temperature can be set at the desired value by adjusting the composition of the thermosensitive copolymer.
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Self-organized materials and graft copolymers of polymethylmethacrylate and polyamide-6 obtained by reactive blending. POLYMER 2005. [DOI: 10.1016/j.polymer.2005.05.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Brainstem auditory evoked responses that disappear during sleep: a possible manifestation of a neurogenic vestibular evoked response. ELECTROMYOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 2005; 45:263-6. [PMID: 16218193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
OBJECTIVE To present a case of unilateral hearing loss in which a brainstem auditory evoked potential (BAEP) disappeared during sleep on the symptomatic side, and to argue that this may actually be a manifestation of a neurogenic vestibular evoked potential (NVESTEP). MATERIAL AND METHOD Brainstem auditory evoked potentials were performed in the standard manner. RESULT A poorly organized response was obtained during wakefulness on the symptomatic side that resembled a BAEP. The BAEP for the right ear was better organized. During sleep, the response for the left ear disappeared. CONCLUSIONS The poor organization of the response of the left ear compared to the right, and its disappearance during sleep, suggests that the response for the left ear was actually an NVESTEP and not a BAEP. The possibility of recording vestibular responses with auditory stimuli may have important implications for BAEP examinations performed during wakefulness that may lead to false negative results, in neonatal screening for hearing loss that use tone stimuli, and also in brain mapping using magnetic resonance imaging (MRI) and positron emission tomography (PET) relating to the auditory cortex.
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Vestibular symptoms and signs are correlated with abnormal neurogenic vestibular evoked potentials in patients with multiple sclerosis. ELECTROMYOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 2005; 45:195-201. [PMID: 16083141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
OBJECTIVES Symptoms of disequilibrium in multiple sclerosis (MS) are common. Neurogenic vestibular evoked potentials (NVsEPs) are saccular responses to tone-pip acoustic stimuli and are recordable from the parietal areas ipsilaterally to the stimulated ear. We wished to determine possible correlations of abnormal findings in NVsEP with clinical neurological findings related to the vestibular system, and demyelination seen on MRI. PATIENTS AND METHODS NVsEPs were performed by delivering a 1 kHz tone-pip stimulus monoaurally with contralateral masking noise via headphones. Brainstem auditory evoked potentials were performed in the standard manner. RESULTS Thirty-three patients had either been diagnosed with MS or had possible MS. There is statistical evidence that the presence of symptoms is likely to give an abnormal NVsEP, but no correlation exists between the presence or absence of vestibular symptoms and signs and an abnormal BAEP. No correlation was found between the presence of brainstem lesions on MRI and an abnormal NVsEP. Correlation exists between abnormal NVsEP and the level of disability using Expanded Disability Status Scale scores. CONCLUSION We have found that with increasing involvement of abnormal NVsEPs, there is a significant correlation with symptoms and signs that can be referred to the vestibular system.
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Adsorption and aggregation of cationic amphiphilic polyelectrolytes on silica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:2855-2864. [PMID: 15779958 DOI: 10.1021/la047311y] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The adsorption of two cationic amphiphilic polyelectrolytes, which are copolymers of two charged monomers, triethyl(vinylbenzyl)ammonium chloride and dimethyldodecyl(vinylbenzyl)ammonium chloride (which is the amphiphilic one) with different contents of amphiphilic groups (40% (40DT) and 80% (80DT)), onto the hydrophilic silica-aqueous solution interface has been studied by in situ null ellipsometry and tapping mode atomic force microscopy (AFM). Adsorption isotherms for both polyelectrolytes were obtained at 25 degrees C and at different ionic strengths, and the adsorption kinetics was also investigated. At low ionic strength, thin adsorbed layers were observed for both polyelectrolytes. The adsorption increases with polymer concentration and reaches, in most cases, a plateau at a concentration below 50 ppm. For the 80DT polymer, at higher ionic strength, an association into aggregates occurs at concentrations at and above 50 ppm. The aggregates were observed directly by AFM at the surface, and by dynamic light scattering in the solution. The adsorption data for this case demonstrated multilayer formation, which correlates well with the increase in viscosity with the ionic strength observed for 80DT.
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Neurogenic vestibular evoked potentials in three cases of vestibular system dysfunction. ELECTROMYOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 2005; 45:39-45. [PMID: 15773263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
OBJECTIVES To demonstrate that neurogenic vestibular evoked potentials (NVsEP) may be specific to the vestibular system using three cases of vestibular system dysfunction and normal auditory function, METHODS Neurogenic vestibular evoked potentials were performed by recording from the parietal areas of the scalp using a tone-pip auditory stimulus via headphones. Brainstem auditory evoked potentials (BAEPs) and NVsEP were performed in all three cases. RESULTS Brainstem auditory evoked potentials were within normal limits in all three cases. All three patients showed abnormalities in their NVsEP In the third case, the responses normalized after treatment. CONCLUSIONS The findings support further the hypothesis that NVsEP are specific to the vestibular system and are a separate response from the BAEP SIGNIFICANCE: Neurogenic vestibular evoked potentials is an easy examination to carry out and can be performed in any clinical neurophysiological laboratory that is familiar with BAEPs. Examinations used to diagnose vestibular system disorders at present include the glycerol dehydration test, electrocochleography, myogenic vestibular evoked potentials and electronystagmography. Neurogenic vestibular evoked potentials may also prove to be useful.
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