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1.
J Pediatr ; 241: 36-41.e2, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34619115

RESUMEN

OBJECTIVE: To evaluate the impact of a novel nurse-led transition intervention program designed for young adolescents (age 13-14 years) with congenital heart disease (CHD). We hypothesized that the intervention would result in improved self-management skills and CHD knowledge. STUDY DESIGN: Single-center cluster randomized controlled trial of a nurse-led transition intervention vs usual care. The intervention group received a 1-hour individualized session with a cardiology nurse, focusing on CHD education and self-management. The primary end point was change in TRANSITION-Q (transition readiness) score between baseline and 6 months. The secondary end point was change in MyHeart score (CHD knowledge). RESULTS: We randomized 60 participants to intervention (n = 30) or usual care (n = 30). TRANSITION-Q score (range 0-100) increased from 49 ± 10 at baseline to 54 ± 9.0 at 6 months (intervention) vs 47 ± 14 to 44 ± 14 (usual care). Adjusted for baseline score, TRANSITION-Q scores at 1 and 6 months were greater in the intervention group (mean difference 5.9, 95% CI 1.3-10.5, P = .01). MyHeart score (range 0-100) increased from 48 ± 24 at baseline to 71 ± 16 at 6 months (intervention) vs 54 ± 24 to 57 ± 22 (usual care). Adjusted for baseline score, MyHeart scores at 1 and 6 months were greater in the intervention group (mean difference 19, 95% CI 12-26, P < .0001). Participants aged 14 years had a greater increase in TRANSITION-Q score at 6 months compared with 13-year-old participants (P < .05). CONCLUSIONS: A nurse-led program improved transition readiness and CHD knowledge among young adolescents. This simple intervention can be readily adopted in other healthcare settings. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02374892.


Asunto(s)
Cardiopatías Congénitas , Transición a la Atención de Adultos/organización & administración , Adolescente , Femenino , Humanos , Masculino , Educación del Paciente como Asunto , Automanejo
2.
BMC Cardiovasc Disord ; 16: 127, 2016 06 06.
Artículo en Inglés | MEDLINE | ID: mdl-27266868

RESUMEN

BACKGROUND: The population of adolescents and young adults with congenital heart disease (CHD) is growing exponentially. These survivors are at risk of late cardiac complications and require lifelong cardiology care. However, there is a paucity of data on how to prepare adolescents to assume responsibility for their health and function within the adult health care system. Evidence-based transition strategies are required. METHODS: The Congenital Heart Adolescents Participating in Transition Evaluation Research (CHAPTER 2) Study is a two-site cluster randomized clinical trial designed to evaluate the efficacy of a nurse-led transition intervention for 16-17 year olds with moderate or complex CHD. The primary endpoint is excess time to adult CHD care, defined as the time interval between the final pediatric cardiology appointment and the first adult CHD appointment, minus the recommended time interval between these appointments. Secondary endpoints include the MyHeart score (CHD knowledge), Transition Readiness Assessment Questionnaire score, and need for catheter or surgical re-intervention. Participants are enrolled in clusters based on week of attendance in the pediatric cardiology clinic. The intervention consists of two one-hour individualized sessions between a cardiology nurse and study participant. Session One focuses on knowledge of the participant's CHD, review of their cardiac anatomy and prior interventions, and potential late cardiac complications. Session Two focuses on self-management and communication skills through review and discussion of videos and role-play. The study will recruit 120 participants. DISCUSSION: Many adolescents and young adults experience a gap in care predisposing them to late cardiac complications. The CHAPTER 2 Study will investigate the impact of a nurse-led transition intervention among adolescents with CHD. Fidelity of the intervention is a major focus and priority. This study will build on our experience by (i) enrolling at two tertiary care programs, (ii) including a self-management intervention component, and (iii) evaluating the impact of the intervention on time to ACHD care, a clinically relevant outcome. The results of this study will inform pediatric cardiology programs, patients and policy makers in judging whether a structured intervention program provides clinically meaningful outcomes for adolescents and young adults living with CHD. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT01723332.


Asunto(s)
Manejo de la Enfermedad , Cardiopatías Congénitas/terapia , Transición a la Atención de Adultos , Adolescente , Adulto , Femenino , Cardiopatías Congénitas/enfermería , Humanos , Masculino , Encuestas y Cuestionarios , Adulto Joven
3.
Cardiol Young ; 26(7): 1359-64, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26786141

RESUMEN

BACKGROUND: Heart murmurs are common in children and may represent congenital or acquired cardiac pathology. Auscultation is challenging and many primary-care physicians lack the skill to differentiate innocent from pathologic murmurs. We sought to determine whether computer-aided auscultation (CardioscanTM) identifies which children require referral to a cardiologist. METHODS: We consecutively enrolled children aged between 0 and 17 years with a murmur, innocent or pathologic, being evaluated in a tertiary-care cardiology clinic. Children being evaluated for the first time and patients with known cardiac pathology were eligible. We excluded children who had undergone cardiac surgery previously or were unable to sit still for auscultation. CardioscanTM auscultation was performed in a quiet room with the subject in the supine position. The sensitivity and specificity of a potentially pathologic murmur designation by CardioscanTM - that is, requiring referral - was determined using echocardiography as the reference standard. RESULTS: We enrolled 126 subjects (44% female) with a median age of 1.7 years, with 93 (74%) having cardiac pathology. The sensitivity and specificity of a potentially pathologic murmur determination by CardioscanTM for identification of cardiac pathology were 83.9 and 30.3%, respectively, versus 75.0 and 71.4%, respectively, when limited to subjects with a heart rate of 50-120 beats per minute. The combination of a CardioscanTM potentially pathologic murmur designation or an abnormal electrocardiogram improved sensitivity to 93.5%, with no haemodynamically significant lesions missed. CONCLUSIONS: Sensitivity of CardioscanTM when interpreted in conjunction with an abnormal electrocardiogram was high, although specificity was poor. Re-evaluation of computer-aided auscultation will remain necessary as advances in this technology become available.


Asunto(s)
Auscultación Cardíaca/métodos , Soplos Cardíacos/diagnóstico , Tamizaje Masivo/métodos , Programas Informáticos/normas , Adolescente , Canadá , Niño , Preescolar , Ecocardiografía , Electrocardiografía , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Derivación y Consulta , Sensibilidad y Especificidad , Centros de Atención Terciaria
4.
Cardiol Young ; 23(4): 568-81, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23083542

RESUMEN

BACKGROUND: Marfan syndrome causes aortic dilation leading to dissection and death. This systematic review examined the use of beta-blockers, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers in the management of aortic dilation in this disease. METHODS: We searched four databases--Medline, EMBASE, Web of Science, and The Cochrane Central Register of Controlled Trials--two conference proceedings, references of retrieved articles, and a web-based trial registry. The primary outcome was mortality. The secondary outcomes were aortic dissection, need for elective surgical repair, change in aortic dilation, and adverse events. Two reviewers selected studies, abstracted data, and assessed study quality. Meta-analyses were not performed because of study heterogeneity. RESULTS: A total of 18 studies were included--12 completed and six in progress. Of the completed studies, three before-and-after treatment, one prospective cohort, three retrospective cohorts, and two randomised control trials examined beta-blockers; one randomised and one non-randomised trial examined angiotensin-converting enzyme inhibitors; and one retrospective cohort study examined angiotensin II receptor blockers. Studies in progress are all randomised trials. Mortality was not impacted by drug therapy, although studies were underpowered with respect to this outcome. All drug classes were associated with a decrease in the rate of aortic dilation (angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers >beta-blockers); none had an impact on other secondary outcomes. CONCLUSIONS: On the basis of existing evidence, beta-blockers, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers slow the progression of aortic dilation in Marfan syndrome. Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers may have more effect than beta-blockers; however, more methodologically rigorous studies currently in progress are needed to evaluate the impact of drug therapy on clinical outcomes.


Asunto(s)
Antagonistas Adrenérgicos beta/uso terapéutico , Antagonistas de Receptores de Angiotensina/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Aneurisma de la Aorta/tratamiento farmacológico , Síndrome de Marfan/tratamiento farmacológico , Aneurisma de la Aorta/etiología , Enfermedades de la Aorta/tratamiento farmacológico , Dilatación Patológica/tratamiento farmacológico , Humanos , Síndrome de Marfan/complicaciones , Resultado del Tratamiento
5.
Cardiol Young ; 22(3): 307-15, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22013913

RESUMEN

OBJECTIVE: To identify risk factors for loss to cardiology follow-up among children and young adults with congenital heart disease. METHODS: We used a matched case-control design. Cases were born before January, 2001 with moderate or complex congenital heart disease and were previously followed up in the paediatric or adult cardiology clinic, but not seen for 3 years or longer. Controls had been seen within 3 years. Controls were matched 3:1 to cases by year of birth and congenital heart disease lesion. Medical records were reviewed for potential risk factors for loss to follow-up. A subset of cases and controls participated in recorded telephone interviews. RESULTS: A total of 74 cases (66% male) were compared with 222 controls (61% male). A history of missed cardiology appointments was predictive of loss to follow-up for 3 years or longer (odds ratio 13.0, 95% confidence interval 3.3-51.7). Variables protective from loss to follow-up were higher family income (odds ratio 0.87 per $10,000 increase, 0.77-0.98), cardiac catheterisation within 5 years (odds ratio 0.2, 95% confidence interval 0.1-0.6), and chart documentation of the need for cardiology follow-up (odds ratio 0.4, 95% confidence interval 0.2-0.8). Cases lacked awareness of the importance of follow-up and identified primary care physicians as their primary source of information about the heart, rather than cardiologists. Unlike cases, controls had methods to remember appointments. CONCLUSIONS: A history of one or more missed cardiology appointments predicted loss to follow-up for 3 or more years, as did lack of awareness of the need for follow-up. Higher family income, recent catheterisations, and medical record documentation of the need for follow-up were protective.


Asunto(s)
Citas y Horarios , Cardiología/estadística & datos numéricos , Cardiopatías Congénitas/terapia , Cooperación del Paciente/estadística & datos numéricos , Adolescente , Adulto , Canadá , Estudios de Casos y Controles , Continuidad de la Atención al Paciente , Femenino , Humanos , Modelos Logísticos , Masculino , Análisis Multivariante , Factores de Riesgo
6.
J Proteome Res ; 8(12): 5550-8, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19817432

RESUMEN

Pneumonia, an infection of the lower respiratory tract, is caused by any of a number of different microbial organisms including bacteria, viruses, fungi, and parasites. Community-acquired pneumonia (CAP) causes a significant number of deaths worldwide, and is the sixth leading cause of death in the United States. However, the pathogen(s) responsible for CAP can be difficult to identify, often leading to delays in appropriate antimicrobial therapies. In the present study, we use nuclear magnetic resonance spectroscopy to quantitatively measure the profile of metabolites excreted in the urine of patients with pneumonia caused by Streptococcus pneumoniae and other microbes. We found that the urinary metabolomic profile for pneumococcal pneumonia was significantly different from the profiles for viral and other bacterial forms of pneumonia. These data demonstrate that urinary metabolomic profiles may be useful for the effective diagnosis of CAP.


Asunto(s)
Infecciones Comunitarias Adquiridas/diagnóstico , Metaboloma , Neumonía Neumocócica/diagnóstico , Orina/química , Anciano , Infecciones Comunitarias Adquiridas/microbiología , Femenino , Humanos , Espectroscopía de Resonancia Magnética , Masculino , Metabolómica/métodos , Persona de Mediana Edad , Neumonía Neumocócica/microbiología , Neumonía Neumocócica/orina , Especificidad de la Especie , Streptococcus pneumoniae
7.
J Am Coll Cardiol ; 71(16): 1768-1777, 2018 04 24.
Artículo en Inglés | MEDLINE | ID: mdl-29673467

RESUMEN

BACKGROUND: There is little evidence regarding the efficacy of interventions to prepare adolescents with congenital heart disease (CHD) to enter adult care. OBJECTIVES: The goal of this study was to evaluate the impact of a nurse-led transition intervention on lapses between pediatric and adult care. METHODS: A cluster randomized clinical trial was conducted of a nurse-led transition intervention for 16- to 17-year-olds with moderate or complex CHD versus usual care. The intervention group received two 1-h individualized sessions targeting CHD education and self-management skills. The primary outcome was excess time to adult CHD care, defined as the interval between the final pediatric and first adult cardiology appointments, minus the recommended time interval, analyzed by using Cox proportional hazards regression accounting for clustering. Secondary outcomes included scores on the MyHeart CHD knowledge survey and the Transition Readiness Assessment Questionnaire. RESULTS: A total of 121 participants were randomized to receive the intervention (n = 58) or usual care (n = 63). At the recommended time of first adult appointment (excess time = 0), intervention participants were 1.8 times more likely to have their appointment within 1 month (95% confidence interval: 1.1 to 2.9; Cox regression, p = 0.018). This hazard increased with time; at an excess time of 6 months, intervention participants were 3.0 times more likely to have an appointment within 1 month (95% confidence interval: 1.1 to 8.3). The intervention group had higher scores at 1, 6, 12, and 18 months on the MyHeart knowledge survey (mixed models, p < 0.001) and the Transition Readiness Assessment Questionnaire self-management index (mixed models, p = 0.032). CONCLUSIONS: A nurse-led intervention reduced the likelihood of a delay in adult CHD care and improved CHD knowledge and self-management skills. (Congenital Heart Adolescents Participating in Transition Evaluation Research [CHAPTER 2]; NCT01723332).


Asunto(s)
Cardiopatías Congénitas , Transición a la Atención de Adultos , Adolescente , Cardiología/estadística & datos numéricos , Femenino , Humanos , Masculino , Automanejo , Adulto Joven
8.
J Spec Pediatr Nurs ; 21(3): 139-46, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27373700

RESUMEN

PURPOSE: This study aimed to measure parents' readiness for discharge from a pediatric cardiology/cardiac surgical inpatient unit. DESIGN AND METHODS: An observational study was conducted at a single tertiary care pediatric cardiac surgical program; parents received teaching from a discharge coordinator, bedside nurse, and, if needed, dietician and pharmacist. We surveyed parents/guardians on the day of discharge and 2 weeks later. RESULTS: We enrolled 181 participants, 53% with children <12 months of age. Length of hospital admission ranged from ≤7 days (54%) to >4 weeks (8%). The most common diagnoses were ventricular septal defect (n = 39), atrial septal defect (n = 28), and coarctation of the aorta (n = 20). Home enteral feeding was required for 21 (12%) children, and 167 (92%) were discharged on medications. Nearly all parents (n = 173, 96%) felt they were ready to take their child home as planned. With respect to medical needs, problems to watch for, who and when to call, what their child was allowed and not allowed to do, and knowledge about follow-up, >90% of respondents rated their knowledge 8+ (range 0-10). Only 68% of respondents rated their knowledge ≥8 regarding services available in their community. Twenty percent experienced challenges at home for which they felt unprepared. These included infection, pain, and gastrointestinal concerns. PRACTICAL IMPLICATIONS: Most parents felt ready for discharge following multidisciplinary teaching. Greater emphasis is needed on teaching families about services available in the community. Further study is required to determine which parents need additional support and education to avoid unanticipated challenges post discharge.


Asunto(s)
Actitud Frente a la Salud , Cardiopatías Congénitas/psicología , Relaciones Padres-Hijo , Padres/psicología , Alta del Paciente/estadística & datos numéricos , Adaptación Psicológica , Femenino , Cardiopatías Congénitas/cirugía , Humanos , Lactante , Recién Nacido , Unidades de Cuidado Intensivo Pediátrico , Masculino , Aceptación de la Atención de Salud/psicología , Relaciones Profesional-Familia
9.
Heart ; 100(14): 1113-8, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24842870

RESUMEN

OBJECTIVES: Adolescents with heart disease have complex health needs and require lifelong cardiology follow-up. Interventions to facilitate paediatric to adult healthcare transition are recommended, although outcomes are unknown. We sought to determine the impact of a transition intervention on improving knowledge and self-management skills among this population. METHODS: We conducted a clinical trial of 15-17 year olds with moderate or complex congenital heart disease (CHD) or cardiomyopathy. Participants were systematically allocated to either usual care (controls) or a 1 h nurse-led one-on-one teaching session about their heart. Allocation was determined by week of attendance in the cardiology clinic. The primary outcome was change in Transition Readiness Assessment Questionnaire (TRAQ) score at 6 months, possible scores ranging from 1 (low) to 5 (optimal). Cardiac knowledge (MyHeart score, range 0-100) was a secondary outcome. Analysis was intention to treat. RESULTS: Of 58 participants (48% female), 52 had CHD and 6 had cardiomyopathy. 27 were allocated to the intervention group; 3 declined the intervention and received usual care. When comparing the intervention group with the usual care group at 6 months postintervention, the mean self-management TRAQ score was 3.59 (±0.83) vs. 3.16 (±1.05), respectively (p=0.048, adjusted for baseline score); the mean self-advocacy TRAQ score was 4.38 (±0.56) vs. 4.01 (±0.95) (p=0.18) and the mean MyHeart score was 75% (±15) vs. 61% (±25) (p=0.019). CONCLUSIONS: A 1 h nurse-led transition intervention resulted in a significant improvement in self-management and cardiac knowledge scores. An educational intervention should be routine for youth with congenital or acquired heart disease. TRIAL REGISTRATION NUMBER: NCT01286480.


Asunto(s)
Cardiomiopatías/enfermería , Conocimientos, Actitudes y Práctica en Salud , Cardiopatías Congénitas/enfermería , Educación del Paciente como Asunto , Autocuidado , Transición a la Atención de Adultos , Adolescente , Cardiomiopatías/terapia , Estudios de Casos y Controles , Manejo de la Enfermedad , Femenino , Estudios de Seguimiento , Necesidades y Demandas de Servicios de Salud , Cardiopatías Congénitas/terapia , Hospitales Pediátricos , Humanos , Masculino , Evaluación de Necesidades , Rol de la Enfermera , Autocuidado/métodos , Encuestas y Cuestionarios , Resultado del Tratamiento
10.
J Proteome Res ; 8(6): 3029-36, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19368345

RESUMEN

Pneumonia is an infection of the lower respiratory tract caused by microbial pathogens. Two such pathogens, Streptococcus pneumoniae and Staphylococcus aureus, are the most common causes of community-acquired and hospital-acquired pneumonia respectively. Each expresses strains highly resistant to penicillin and other antibiotics, and a significant number of people succumb to infection by these pathogens every year. Urinary metabolite changes in a C57Bl/6 mouse model with lung infection from either S. pneumoniae or S. aureus were characterized using multivariate targeted profiling data obtained from (1)H NMR spectra. Marked changes in the urinary metabolite profile occurred within 24 h after infection with either pathogen. Specifically, significant decreases in TCA cycle intermediates, coupled with increases in fucose, creatine, and taurine were observed in the urine of S. pneumoniae-treated mice. Infection with S. aureus resulted in the decrease of a number of urinary metabolites including 1-methylnicotinamide, 3-methyl-2-oxovalerate, 2-oxoisocaproate, N-isovaleroylglycine and others. Disturbances in gut-derived microbial metabolites were also observed. Analysis of metabolic trajectory data indicated that, as the mice recovered from infection, their urinary metabolic profile became similar to that of the preinfected state. These results underline the potential of metabolomics as a tool for diagnosis, health monitoring, and drug development, and show its usefulness for understanding microbial-host interactions.


Asunto(s)
Metaboloma , Metabolómica/métodos , Staphylococcus aureus Resistente a Meticilina , Neumonía Neumocócica/metabolismo , Neumonía Estafilocócica/metabolismo , Animales , Líquido del Lavado Bronquioalveolar/citología , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos C57BL , Análisis Multivariante , Resonancia Magnética Nuclear Biomolecular , Neumonía Neumocócica/orina , Neumonía Estafilocócica/microbiología , Neumonía Estafilocócica/orina , Análisis de Componente Principal
11.
J Bacteriol ; 189(9): 3502-14, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17277060

RESUMEN

Pseudomonas fluorescens strain KU-7 is a prototype microorganism that metabolizes 2-nitrobenzoate (2-NBA) via the formation of 3-hydroxyanthranilate (3-HAA), a known antioxidant and reductant. The initial two steps leading to the sequential formation of 2-hydroxy/aminobenzoate and 3-HAA are catalyzed by a NADPH-dependent 2-NBA nitroreductase (NbaA) and 2-hydroxylaminobenzoate mutase (NbaB), respectively. The 216-amino-acid protein NbaA is 78% identical to a plasmid-encoded hypothetical conserved protein of Polaromonas strain JS666; structurally, it belongs to the homodimeric NADH:flavin mononucleotide (FMN) oxidoreductase-like fold family. Structural modeling of complexes with the flavin, coenzyme, and substrate suggested specific residues contributing to the NbaA catalytic activity, assuming a ping-pong reaction mechanism. Mutational analysis supports the roles of Asn40, Asp76, and Glu113, which are predicted to form the binding site for a divalent metal ion implicated in FMN binding, and a role in NADPH binding for the 10-residue insertion in the beta5-alpha2 loop. The 181-amino-acid sequence of NbaB is 35% identical to the 4-hydroxylaminobenzoate lyases (PnbBs) of various 4-nitrobenzoate-assimilating bacteria, e.g., Pseudomonas putida strain TW3. Coexpression of nbaB with nbaA in Escherichia coli produced a small amount of 3-HAA from 2-NBA, supporting the functionality of the nbaB gene. We also showed by gene knockout and chemotaxis assays that nbaY, a chemoreceptor NahY homolog located downstream of the nbaA gene, is responsible for strain KU-7 being attracted to 2-NBA. NbaY is the first chemoreceptor in nitroaromatic metabolism to be identified, and this study completes the gene elucidation of 2-NBA metabolism that is localized within a 24-kb chromosomal locus of strain KU-7.


Asunto(s)
Aminobenzoatos/metabolismo , Transferasas Intramoleculares/genética , Transferasas Intramoleculares/metabolismo , Nitrobenzoatos/metabolismo , Nitrorreductasas/genética , Nitrorreductasas/metabolismo , Pseudomonas fluorescens/metabolismo , Ácido 3-Hidroxiantranílico/metabolismo , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Sitios de Unión/genética , Quimiotaxis , Clonación Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Eliminación de Gen , Expresión Génica , Transferasas Intramoleculares/química , Modelos Biológicos , Modelos Moleculares , Datos de Secuencia Molecular , Mutación , Nitrorreductasas/química , Estructura Terciaria de Proteína , Pseudomonas fluorescens/enzimología , Pseudomonas fluorescens/genética , Pseudomonas fluorescens/fisiología , Pseudomonas putida/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido
12.
J Chem Inf Model ; 47(1): 122-33, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17238257

RESUMEN

We present a binding free energy function that consists of force field terms supplemented by solvation terms. We used this function to calibrate the solvation model along with the binding interaction terms in a self-consistent manner. The motivation for this approach was that the solute dielectric-constant dependence of calculated hydration gas-to-water transfer free energies is markedly different from that of binding free energies (J. Comput. Chem. 2003, 24, 954). Hence, we sought to calibrate directly the solvation terms in the context of a binding calculation. The five parameters of the model were systematically scanned to best reproduce the absolute binding free energies for a set of 99 protein-ligand complexes. We obtained a mean unsigned error of 1.29 kcal/mol for the predicted absolute binding affinity in a parameter space that was fairly shallow near the optimum. The lowest errors were obtained with solute dielectric values of Din = 20 or higher and scaling of the intermolecular van der Waals interaction energy by factors ranging from 0.03 to 0.15. The high apparent Din and strong van der Waals scaling may reflect the anticorrelation of the change in solvated potential energy and configurational entropy, that is, enthalpy-entropy compensation in ligand binding (Biophys. J. 2004, 87, 3035-3049). Five variations of preparing the protein-ligand data set were explored in order to examine the effect of energy refinement and the presence of bound water on the calculated results. We find that retaining water in the final protein structure used for calculating the binding free energy is not necessary to obtain good results; that is the continuum solvation model is sufficient. Virtual screening enrichment studies on estrogen receptor and thymidine kinase showed a good ability of the binding free energy function to recover true hits in a collection of decoys.


Asunto(s)
Proteínas/química , Solubilidad , Termodinámica , Ligandos , Modelos Químicos , Unión Proteica
13.
Anal Chem ; 79(18): 6995-7004, 2007 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-17702530

RESUMEN

Metabolomics may have the capacity to revolutionize disease diagnosis through the identification of scores of metabolites that vary during environmental, pathogenic, or toxicological insult. NMR spectroscopy has become one of the main tools for measuring these changes since an NMR spectrum can accurately identify metabolites and their concentrations. The predominant approach in analyzing NMR data has been through the technique of spectral binning. However, identification of spectral areas in an NMR spectrum is insufficient for diagnostic evaluation, since it is unknown whether areas of interest are strictly caused by metabolic changes or are simply artifacts. In this paper, we explore differences in gender, diurnal variation, and age in a human population. We use the example of gender differences to compare traditional spectral binning techniques (NMR spectral areas) to novel targeted profiling techniques (metabolites and their concentrations). We show that targeted profiling produces robust models, generates accurate metabolite concentration data, and provides data that can be used to help understand metabolic differences in a healthy population. Metabolites relating to mitochondrial energy metabolism were found to differentiate gender and age. Dietary components and some metabolites related to circadian rhythms were found to differentiate time of day urine collection. The mechanisms by which these differences arise will be key to the discovery of new diagnostic tests and new understandings of the mechanism of disease.


Asunto(s)
Factores de Edad , Ritmo Circadiano/fisiología , Factores Sexuales , Sistema Urinario/metabolismo , Acetilcarnitina/orina , Adulto , Carnitina/orina , Creatina/orina , Femenino , Fumaratos/orina , Humanos , Espectroscopía de Resonancia Magnética , Masculino , Persona de Mediana Edad
14.
J Comput Chem ; 24(8): 954-62, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12720316

RESUMEN

Using molecular mechanics force field partial atomic charges, we show the nonuniqueness of the parametrization of continuum electrostatics models with respect to solute atomic radii and interior dielectric constant based on hydration (vacuum-to-water transfer) free energy data available for small molecules. Moreover, parameter sets that are optimal and equivalent for hydration free energy calculations lead to large variations of calculated absolute and relative electrostatic binding free energies. Hence, parametrization of solvation effects based on hydration data, although a necessary condition, is not sufficient to guarantee its transferability to the calculation of binding free energies in solution.

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