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2.
Sci Data ; 10(1): 124, 2023 03 07.
Article in English | MEDLINE | ID: mdl-36882443

ABSTRACT

WAVES is a large, single-center dataset comprising 9 years of high-frequency physiological waveform data from patients in intensive and acute care units at a large academic, pediatric medical center. The data comprise approximately 10.6 million hours of 1 to 20 concurrent waveforms over approximately 50,364 distinct patient encounters. The data have been de-identified, cleaned, and organized to facilitate research. Initial analyses demonstrate the potential of the data for clinical applications such as non-invasive blood pressure monitoring and methodological applications such as waveform-agnostic data imputation. WAVES is the largest pediatric-focused and second largest physiological waveform dataset available for research.


Subject(s)
Critical Care , Hospitals , Child , Humans
3.
J Cardiovasc Electrophysiol ; 33(11): 2263-2273, 2022 11.
Article in English | MEDLINE | ID: mdl-35924481

ABSTRACT

BACKGROUND: This prospective trial sought to phenotype persistent atrial fibrillation (AF) based on AF mechanisms using electrocardiographic imaging (ECGI) mapping to determine whether this would predict long-term freedom from arrhythmia after pulmonary vein isolation (PVI). METHODS: Patients with persistent AF of <2 years duration underwent cryoballoon PVI. ECGI mapping was performed before PVI to determine potential drivers (PDs) defined as rotational activations completing ≥1.5 revolutions or focal activations. The coprimary endpoint was the association between (1) PD burden (defined as the number of PD occurrences) and (2) PD distribution (defined as the number of segments on an 18-segment model of the atria harboring PDs) with freedom from arrhythmia at 1-year follow up. RESULTS: Of 100 patients, 97 completed follow up and 52 (53.6%) remained in sinus rhythm off antiarrhythmic drugs. Neither PD burden nor PD distribution predicted freedom from arrhythmia (hazard ratio [HR]: 1.01, 95% confidence interval [CI]: 0.99-1.03, p = .164; and HR: 1.04, 95% CI: 0.91-1.17, p = .591, respectively). Otherwise, the burden of rotational PDs, rotational stability, and the burden of PDs occurring at the pulmonary veins and posterior wall all failed to predict arrhythmia recurrence (all p > .10). CONCLUSIONS: AF mechanisms as determined using ECGI mapping do not predict outcomes after PVI for persistent AF. Further studies using different methodologies to characterize AF mechanisms are warranted (NCT03394404).


Subject(s)
Atrial Fibrillation , Catheter Ablation , Pulmonary Veins , Humans , Pulmonary Veins/surgery , Atrial Fibrillation/diagnosis , Atrial Fibrillation/surgery , Prospective Studies , Recurrence , Treatment Outcome , Electrocardiography , Phenotype , Catheter Ablation/adverse effects , Catheter Ablation/methods
4.
Pediatr Crit Care Med ; 23(11): 860-871, 2022 11 01.
Article in English | MEDLINE | ID: mdl-35894607

ABSTRACT

OBJECTIVES: IV calcium administration during cardiopulmonary resuscitation (CPR) for pediatric in-hospital cardiac arrest (IHCA) is associated with worse survival. We evaluated survival to hospital discharge in children with heart disease (HD), where calcium is more frequently administered during CPR. DESIGN: Retrospective study of a multicenter registry database. SETTING: Data reported to the American Heart Association's (AHA) Get With The Guidelines-Resuscitation registry. PATIENTS: Children younger than 18 years with HD experiencing an index IHCA event requiring CPR between January 2000 and January 2019. Using propensity score matching (PSM), we selected matched cohorts of children receiving and not receiving IV calcium during CPR and compared the primary outcome of survival to hospital discharge. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We included 4,556 children with HD experiencing IHCA. Calcium was administered in 1,986 (44%), more frequently in children younger than 1 year old (65% vs 35%; p < 0.001) and surgical cardiac (SC) compared with medical cardiac patients (51% vs 36%; p < 0.001). Calcium administration during CPR was associated with longer duration CPR (median 27 min [interquartile range (IQR): 10-50 min] vs 5 min [IQR, 2-16 min]; p < 0.001) and more frequent extracorporeal-CPR deployment (25% vs 8%; p < 0.001). In the PSM cohort, those receiving calcium had decreased survival to hospital discharge (39% vs 46%; p = 0.02) compared with those not receiving calcium. In a subgroup analysis, decreased discharge survival was only seen in SC cohorts. CONCLUSIONS: Calcium administration during CPR for children with HD experiencing IHCA is common and is associated with worse survival. Administration of calcium during CPR in children with HD should be restricted to specific indications as recommended by the AHA CPR guidelines.


Subject(s)
Cardiopulmonary Resuscitation , Heart Arrest , Heart Diseases , Infant , Child , Humans , Calcium , Retrospective Studies , American Heart Association , Heart Arrest/therapy , Registries , Hospitals
6.
Waste Manag ; 121: 237-247, 2021 Feb 15.
Article in English | MEDLINE | ID: mdl-33385952

ABSTRACT

In the present study, the potential use of cellulosic microfibers (CMFs) extracted from hemp fiber (HF) and pulp and paper solid waste (mixed sludge (MS), deinked sludge (DS)) as a reinforcing agent in novel bio composite materials produced from recycled Polylactic acid (rPLA) was investigated. CMFs were extracted and treated using physicochemical method followed by enzymatic treatment with laccase and cellulase. The effects of CMFs concentrations (1.5, 3 and 6% w/w) and fiber size (75 µm-1.7 mm) on the mechanical properties (impact and tensile) and biodegradability of the biocomposite samples were investigated. A modified interfacial adhesion between rPLA matrix and the three fibers used, was clearly observed through mechanical tests due to alkali and enzymatic treatments. The use of different types of enzymatically treated cellulosic fibers for polylactic acid (PLA) recycling was assessed by Scaning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The combined physicochemical and enzymatic treatments led to a considerable size reduction of the cellulosic fibers (HF, MS and DS) resulting in the enhanced interfacial adhesion between rPLA matrix and fibers. The biocomposite obtained with rPLA with HF gave the most favorable values for Young's modulus (324.53 ± 3.10 MPa, p-value 0.03), impact strength (27.61 ± 2.94 kJ/m2, p-value 0.01) and biodegradation rate (1.97%).


Subject(s)
Polyesters , Recycling , Feasibility Studies , X-Ray Diffraction
7.
Semin Thorac Cardiovasc Surg ; 32(4): 947-957, 2020.
Article in English | MEDLINE | ID: mdl-32621963

ABSTRACT

Children with Down syndrome (DS) have lower mortality compared to nonsyndromic (NS) children after atrioventricular septal defect (AVSD) repair. Limited data exist regarding hospital mortality and utilization after other congenital heart disease (CHD) operations in DS. We compared hospital mortality and utilization after CHD operations in both populations and hypothesized that the survival benefit in children with DS is not consistent across CHD lesions. The Texas Inpatient Public Use Datafile was queried for all patients <18 years old undergoing operations for CHD between 1999 and 2016. Hospital mortality, length-of-stay and charges were compared between DS and NS groups, stratified by CHD operation using mixed-effects multivariable analyses and propensity score matching analyses adjusting for prematurity, low birth weight, age, and sex. Over the 18-year period, 2841 cases with DS underwent CHD operations compared to 25,063 NS cases. The most common types of interventions performed in DS were AVSD repair, isolated ventricular septal defect (VSD) repair and tetralogy of Fallot (TOF) repair. By multivariable analyses, DS was associated with lower mortality after isolated AVSD repair (RR 0.40 [IQR 0.20-0.79]), and higher hospital mortality after bidirectional Glenn anastomosis (BDG) (RR 5.17 [IQR 2.10-12.77]) and TOF/pulmonary atresia repair (RR 9.71 [IQR 2.16-43.68]) compared to NS children. Similar results were noted using propensity score matching. Children with DS had lower mortality after AVSD repair than NS children, but higher mortality after operations for BDG and TOF/pulmonary atresia. Further study is needed to determine if the presence of pulmonary hypertension in DS modifies the association between DS and mortality depending on cardiac lesion.


Subject(s)
Cardiac Surgical Procedures , Down Syndrome , Heart Defects, Congenital , Adolescent , Cardiac Surgical Procedures/adverse effects , Child , Down Syndrome/complications , Down Syndrome/diagnosis , Heart Defects, Congenital/diagnosis , Heart Defects, Congenital/surgery , Hospital Mortality , Humans , Infant , Retrospective Studies , Texas
8.
J Cardiovasc Electrophysiol ; 31(4): 903-912, 2020 04.
Article in English | MEDLINE | ID: mdl-32048786

ABSTRACT

BACKGROUND: Noninvasive mapping identifies potential drivers (PDs) in atrial fibrillation (AF). We analyzed the impact of pulmonary vein isolation (PVI) on PDs and whether baseline PD pattern predicted termination of AF. METHODS: Patients with persistent AF less than 2 years underwent electrocardiographic imaging mapping before and after cryoballoon PVI. We recorded the number of PD occurrences, characteristics (rotational wavefronts ≥ 1.5 revolutions or focal activations), and distribution using an 18-segment atrial model. RESULTS: Of 100 patients recruited, PVI terminated AF in 15 patients; 21.3% ± 9.1% (8.7 ± 4.8) of PDs occurred at the pulmonary veins (PVs) and posterior wall. PVI had no impact on PD occurrences outside the PVs and posterior wall (33.2 ± 12.9 vs 31.6 ± 12.5; P = .164), distribution over the remaining 13 segments (9 [8-11] vs 9 [8-10]; P = .634), the proportion of PDs that was rotational (82.9% ± 9.7% vs 83.6% ± 10.1%; P = .496), or temporal stability (2.4 ± 0.4 vs 2.4 ± 0.5 rotations; P = .541). Fewer focal PDs (area under the curve, 0.683; 95% CI, 0.528-0.839; P = .024) but not rotational PDs (P = .626) predicted AF termination with PVI. CONCLUSIONS: PVI did not have a global impact on PDs outside the PVs and posterior wall. Although fewer focal PDs predicted termination of AF with PVI, the burden of rotational PDs did not. It is accepted though not all PDs are necessarily real or important. Outcome data are needed to confirm whether noninvasive mapping can predict patients likely to respond to PVI.


Subject(s)
Action Potentials , Atrial Fibrillation/surgery , Cryosurgery , Heart Rate , Pulmonary Veins/surgery , Aged , Atrial Fibrillation/diagnosis , Atrial Fibrillation/physiopathology , Cryosurgery/adverse effects , Electrocardiography , Female , Humans , Imaging, Three-Dimensional , Male , Middle Aged , Prospective Studies , Pulmonary Veins/physiopathology , Time Factors , Treatment Outcome
9.
Am J Cardiol ; 124(6): 952-959, 2019 09 15.
Article in English | MEDLINE | ID: mdl-31350000

ABSTRACT

There have been no clinical studies evaluating the use of drug-eluting stents (DES) versus bare metal stents (BMS) for infants who underwent ductus arteriosus (DA) stent placement for ductal-dependent pulmonary blood flow (PBF). We aimed to compare the use of second-generation (fluoropolymer-coated everolimus) DES to BMS in infants who underwent DA stenting for ductal-dependent PBF. A retrospective study of infants who underwent DA stenting for ductal-dependent PBF from January 2004 to March 2018 at a single tertiary care pediatric hospital was performed. Of 94 infants identified, 71 (46 BMS and 25 DES) met inclusion criteria. Baseline characteristics of the DES and BMS cohorts were comparable. The patent lumen to stent diameter on subsequent angiographic evaluation was 81% in DES as compared with 50% in BMS group; p = 0.01. There were 2 deaths early in our experience, both in the BMS group. Unplanned reinterventions were less in the DES group (3, 12% patients) compared with the BMS group (13, 28%), p = 0.03. Pulmonary artery size as assessed using Nakata and pulmonary artery symmetry index was comparable in both the groups. There was no difference in infection rates between the groups. On multivariate analysis, prematurity, BMS, and lower oxygen saturations at discharge were associated with subsequent unplanned reintervention (p = 0.01, 0.03 and 0.03, respectively). In conclusion, our clinical experience suggests that in infants who underwent DA stenting for ductal-dependent PBF, (fluoropolymer-coated everolimus eluting) DES results in less luminal loss and lower unplanned reintervention for cyanosis as compared with BMS implantation.


Subject(s)
Blood Flow Velocity/physiology , Cardiac Surgical Procedures/methods , Drug-Eluting Stents , Ductus Arteriosus, Patent/surgery , Ductus Arteriosus/surgery , Everolimus/pharmacology , Pulmonary Artery/physiopathology , Angiography , Coated Materials, Biocompatible , Ductus Arteriosus/diagnostic imaging , Ductus Arteriosus, Patent/diagnosis , Ductus Arteriosus, Patent/physiopathology , Female , Follow-Up Studies , Humans , Immunosuppressive Agents/pharmacology , Infant, Newborn , Male , Pulmonary Artery/diagnostic imaging , Pulmonary Circulation/physiology , Retrospective Studies , Treatment Outcome
10.
Pediatr Crit Care Med ; 20(3): 233-242, 2019 03.
Article in English | MEDLINE | ID: mdl-30785870

ABSTRACT

OBJECTIVES: Children with medical cardiac disease experience poorer survival to hospital discharge after cardiopulmonary arrest compared with children with surgical cardiac disease. Limited literature exists describing epidemiology and factors associated with mortality in this heterogeneous population. We aim to evaluate the clinical characteristics and outcomes after cardiopulmonary arrest in medical cardiac patients. DESIGN: We performed a retrospective review of pediatric cardiac patients who underwent cardiopulmonary resuscitation in a tertiary care cardiac ICU. Surgical cardiac patients underwent cardiac surgery immediately prior to ICU admission. Nonsurgical cardiac patients were divided into two groups based on the presence of congenital heart disease: congenital heart disease medical or noncongenital heart disease medical. Clinical and outcome variables were collected. Primary outcome was survival to hospital discharge. SETTINGS: Texas Children's Hospital cardiac ICU. PATIENTS: Patients admitted to Texas Children's Hospital cardiac ICU between January 2011 and December 2016. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 150 cardiopulmonary arrest events reviewed, 90 index events were included (46 surgical, 26 congenital heart disease medical, and 18 noncongenital heart disease medical). There was no difference in primary outcome among the three groups. The absence of an epinephrine infusion precardiopulmonary arrest was associated with increased odds of survival in the congenital heart disease medical group (p = 0.03). Noncongenital heart disease medical patients experienced pulseless ventricular tachycardia/ventricular fibrillation more frequently than congenital heart disease medical patients (p = 0.02). Congenital heart disease medical patients had trends toward longer cardiac arrest durations, higher prevalence of neurologic sequelae postcardiopulmonary arrest, and higher mortality when extracorporeal support at cardiopulmonary resuscitation was employed. CONCLUSIONS: Although trends in first documented rhythm, neurologic sequelae, and inotropic support prior to cardiopulmonary arrest were noted between groups, no significant differences in survival after cardiac arrest were seen. Larger scale studies are needed to better describe factors associated with cardiopulmonary arrest as well as survival in heterogeneous medical cardiac populations.


Subject(s)
Heart Diseases/mortality , Heart Diseases/therapy , Intensive Care Units, Pediatric/statistics & numerical data , Age Factors , Cardiac Surgical Procedures/adverse effects , Cardiopulmonary Resuscitation , Child , Child, Preschool , Female , Heart Arrest/mortality , Heart Arrest/physiopathology , Heart Defects, Congenital/mortality , Heart Defects, Congenital/therapy , Heart Diseases/surgery , Humans , Infant , Male , Retrospective Studies , Sex Factors , Time Factors
11.
J Clin Ultrasound ; 46(9): 617-622, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30160304

ABSTRACT

Aortopulmonary window (APW) is a rare form of congenital heart disease seen in isolation or with complex cardiac lesions. APW has been associated with other cardiac defects such as interrupted aortic arch and Tetralogy of Fallot, but few cases have been reported of APW associated with transposition of the great arteries (TGA). In a newborn with TGA and intact ventricular septum, diagnosis of APW requires a high index of suspicion. This article reviews the literature on TGA with APW and illustrates the importance of additional evaluation in neonates with TGA when oxygen saturation and PaO2 do not match predicted clinical values.


Subject(s)
Echocardiography/methods , Transposition of Great Vessels/diagnostic imaging , Transposition of Great Vessels/surgery , Humans , Infant, Newborn , Male
12.
Prenat Diagn ; 38(11): 812-820, 2018 10.
Article in English | MEDLINE | ID: mdl-30047996

ABSTRACT

OBJECTIVES: Fetal endoscopic tracheal occlusion (FETO) is offered to fetuses with congenital diaphragmatic hernia (CDH) and severe lung hypoplasia to promote lung growth and may secondarily affect left heart growth. The effects of FETO on left heart hypoplasia (LHH) are not described post-CDH repair. METHODS: A retrospective analysis was performed for fetuses with left-sided CDH who underwent FETO and severity-matched controls from 2007 to 2016 at our institution. Echocardiographic, ultrasound, and MRI data were reviewed. Left heart dimensions were assessed prenatally and postnatally. Primary clinical outcome evaluated was death. RESULTS: Twelve FETO patients and 18 controls were identified. Fetal LHH was noted in both groups and worsened after FETO. Postnatal mitral valve dimensions were larger in the FETO group pre-CDH repair (P = .03). Post-CDH repair, mitral valve and left ventricular dimensions were not significantly different between groups (P = .79 and P = .63 respectively) while FETO aortic valve dimensions were smaller (P = .04). Extracorporeal membrane oxygenation use was lower in the FETO group. No associations were found between left heart dimensions and outcomes. CONCLUSION: Although increased lung growth was seen after FETO, fetal LHH persisted with relative normalization seen post-repair. Persistent LHH post-FETO could be secondary to a small contribution of pulmonary venous return to the fetal left heart and increased intrathoracic pressures post-FETO.


Subject(s)
Fetal Heart/embryology , Fetoscopy/statistics & numerical data , Hernias, Diaphragmatic, Congenital/surgery , Echocardiography , Female , Fetal Heart/diagnostic imaging , Humans , Infant, Newborn , Magnetic Resonance Imaging , Male , Retrospective Studies , Treatment Outcome
13.
J Pediatr Surg ; 53(9): 1675-1680, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29428594

ABSTRACT

BACKGROUND & OBJECTIVES: Congenital Diaphragmatic Hernia (CDH) is associated with significant morbidity and mortality. This study compares the efficacy of the highest oxygenation index in the first 48 h (HiOI) versus current prenatal indices to predict survival and morbidity. METHODS: Medical records of 50 prenatally diagnosed, isolated, left-sided CDH patients treated from January 2011 to April 2016 were reviewed. Data abstracted included HiOI, lung to head ratio (LHR), observed to expected total fetal lung volume (O/E TFLV), percent liver herniation (%LH), 6 month survival, respiratory support at discharge, ventilator days and length of stay. Data were analyzed using parametric and nonparametric tests and regression analyses as appropriate. RESULTS: HiOI was associated with significantly increased LOS (p<0.001), respiratory support at discharge (p<0.001), greater ventilator days (p=0.001) and higher odds of death (p=0.004) with risk of death increasing by 5% for every one-unit increase in OI. HiOI was statistically a better predictor of LOS than O/E TFLV (p=0.007) and %LH (p=0.02). CONCLUSIONS: In isolated, left-sided CDH patients, HiOI is associated with higher mortality, greater length of stay, more ventilator days and increased respiratory support at discharge. HiOI is a better predictor of length of stay than O/E TFLV and %LH. TYPE OF STUDY: Retrospective Study LEVEL OF EVIDENCE: II.


Subject(s)
Hernias, Diaphragmatic, Congenital/diagnosis , Oxygen/metabolism , Biomarkers/metabolism , Female , Hernias, Diaphragmatic, Congenital/metabolism , Hernias, Diaphragmatic, Congenital/mortality , Hernias, Diaphragmatic, Congenital/therapy , Humans , Infant , Infant, Newborn , Male , Predictive Value of Tests , Prognosis , Regression Analysis , Retrospective Studies
15.
Prenat Diagn ; 37(5): 502-509, 2017 May.
Article in English | MEDLINE | ID: mdl-28370263

ABSTRACT

OBJECTIVES: Fetuses with congenital diaphragmatic hernia (CDH) demonstrate varying degrees of left heart hypoplasia. Our study assesses the relationship between fetal left-sided cardiac structural dimensions, lung size, percentage liver herniation, lung-to-head ratio, postnatal left-sided cardiac structural dimensions, and postnatal outcomes. METHODS: We performed a retrospective cohort study of fetuses with left-sided CDH who had prenatal echocardiographic, ultrasound, and magnetic resonance imaging examinations at our institution between January 2007 and March 2015. Postnatal outcomes assessed include use of inhaled nitric oxide (iNO), use of extracorporeal membrane oxygenation, and death. RESULTS: Fifty-two fetuses with isolated left-sided CDH were included. Multivariate logistic regression models indicated that smaller fetal aortic valve z-score was associated with postnatal use of iNO (p = 0.03). Fetal mitral valve z-score correlated with lung-to-head ratio (p = 0.04), postnatal mitral valve z-score correlated with percent liver herniation (p = 0.03), and postnatal left ventricular end-diastolic dimension z-score correlated with liver herniation <20% (p = 0.04). CONCLUSION: We identified associations between smaller fetal left-sided cardiac structural dimensions and classic CDH indices. Smaller aortic valve z-score was associated with iNO use; however, left heart dimensions showed no association with extracorporeal membrane oxygenation or mortality. Further study into the impact of left-sided hypoplasia on outcomes in CDH is worthy of evaluation in a larger, prospective study. © 2017 John Wiley & Sons, Ltd.


Subject(s)
Fetal Heart/diagnostic imaging , Fetal Heart/pathology , Fetus/diagnostic imaging , Hernias, Diaphragmatic, Congenital/diagnosis , Hypoplastic Left Heart Syndrome/diagnosis , Pregnancy Outcome , Female , Fetus/pathology , Gestational Age , Hernias, Diaphragmatic, Congenital/complications , Hernias, Diaphragmatic, Congenital/pathology , Humans , Hypoplastic Left Heart Syndrome/complications , Hypoplastic Left Heart Syndrome/pathology , Male , Organ Size , Pregnancy , Retrospective Studies , Severity of Illness Index , Ultrasonography, Prenatal
16.
J Sci Food Agric ; 93(7): 1560-7, 2013 May.
Article in English | MEDLINE | ID: mdl-23108761

ABSTRACT

BACKGROUND: The citric acid (CA) industry is currently struggling to develop a sustainable and economical process owing to high substrate and energy costs. Increasing interest in the replacement of costly synthetic substrates by renewable waste biomass has fostered research on agro-industrial wastes and screening of raw materials for economical CA production. The food-processing industry generates substantial quantities of waste biomass that could be used as a valuable low-cost fermentation substrate. The present study evaluated the potential of different agro-industrial wastes, namely apple pomace (AP), brewer's spent grain, citrus waste and sphagnum peat moss, as substrates for solid state CA production using Aspergillus niger NRRL 2001. RESULTS: Among the four substrates, AP resulted in highest CA production of 61.06 ± 1.9 g kg(-1) dry substrate (DS) after a 72 h incubation period. Based on the screening studies, AP was selected for optimisation studies through response surface methodology (RSM). Maximum CA production of 312.32 g kg(-1) DS was achieved at 75% (v/w) moisture and 3% (v/w) methanol after a 144 h incubation period. The validation of RSM-optimised parameters in plastic trays resulted in maximum CA production of 364.4 ± 4.50 g kg(-1) DS after a 120 h incubation period. CONCLUSION: The study demonstrated the potential of AP as a cheap substrate for higher CA production. This study contributes to knowledge about the future application of carbon rich agro-industrial wastes for their value addition to CA. It also offers economic and environmental benefits over traditional ways used to dispose off agro-industrial wastes.


Subject(s)
Aspergillus niger/metabolism , Citric Acid/metabolism , Conservation of Natural Resources , Crops, Agricultural/metabolism , Food-Processing Industry , Industrial Waste , Agriculture , Citrus , Edible Grain , Fermentation , Fruit , Malus , Sphagnopsida
17.
J Clin Imaging Sci ; 1: 48, 2011.
Article in English | MEDLINE | ID: mdl-22059150

ABSTRACT

Magnetic resonance imaging (MRI) of the breast is being performed more frequently to improve primary and recurrent tumor detection, characterization, and response to therapy. Sensitivity of this test approaches 90% and the specificity ranges from 37% to 100%. We present a concise tutorial for the general radiologist with a pictorial review of common lesions identified with breast MRI.

20.
J Hand Surg Am ; 29(4): 605-15; discussion 616-8, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15249083

ABSTRACT

PURPOSE: It is not known whether motor and sensory pathways associated with a missing or denervated limb remain functionally intact over periods of many months or years after amputation or chronic peripheral nerve transection injury. We examined the extent to which activity on chronically severed motor nerve fibers could be controlled by human amputees and whether distally referred tactile and proprioceptive sensations could be induced by stimulation of sensory axons in the nerve stumps. METHODS: Amputees undergoing elective stump procedures were invited to participate in this study. Longitudinal intrafascicular electrodes were threaded percutaneously and implanted in severed nerves of human amputees. The electrodes were interfaced to an amplifier and stimulator system controlled by a laptop computer. Electrophysiologic tests were conducted for 2 consecutive days after recovery from the surgery. RESULTS: It was possible to record volitional motor nerve activity uniquely associated with missing limb movements. Electrical stimulation through the implanted electrodes elicited discrete, unitary, graded sensations of touch, joint movement, and position, referring to the missing limb. CONCLUSIONS: These findings indicate that both central and peripheral motor and somatosensory pathways retain significant residual connectivity and function for many years after limb amputation. This implies that peripheral nerve interfaces could be used to provide amputees with prosthetic limbs that have more natural feel and control than is possible with current myoelectric and body-powered control systems.


Subject(s)
Amputation Stumps/innervation , Amputees , Artificial Limbs , Biofeedback, Psychology , Sensation , Action Potentials , Amputation Stumps/physiopathology , Axons/physiology , Electric Stimulation , Electrodes, Implanted , Humans , Movement/physiology , Proprioception , Touch
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