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BACKGROUND: Bronchopulmonary dysplasia is a prevalent complication after extremely preterm birth. Inflammation with mechanical ventilation may contribute to its development. Whether hydrocortisone treatment after the second postnatal week can improve survival without bronchopulmonary dysplasia and without adverse neurodevelopmental effects is unknown. METHODS: We conducted a trial involving infants who had a gestational age of less than 30 weeks and who had been intubated for at least 7 days at 14 to 28 days. Infants were randomly assigned to receive either hydrocortisone (4 mg per kilogram of body weight per day tapered over a period of 10 days) or placebo. Mandatory extubation thresholds were specified. The primary efficacy outcome was survival without moderate or severe bronchopulmonary dysplasia at 36 weeks of postmenstrual age, and the primary safety outcome was survival without moderate or severe neurodevelopmental impairment at 22 to 26 months of corrected age. RESULTS: We enrolled 800 infants (mean [±SD] birth weight, 715±167 g; mean gestational age, 24.9±1.5 weeks). Survival without moderate or severe bronchopulmonary dysplasia at 36 weeks occurred in 66 of 398 infants (16.6%) in the hydrocortisone group and in 53 of 402 (13.2%) in the placebo group (adjusted rate ratio, 1.27; 95% confidence interval [CI], 0.93 to 1.74). Two-year outcomes were known for 91.0% of the infants. Survival without moderate or severe neurodevelopmental impairment occurred in 132 of 358 infants (36.9%) in the hydrocortisone group and in 134 of 359 (37.3%) in the placebo group (adjusted rate ratio, 0.98; 95% CI, 0.81 to 1.18). Hypertension that was treated with medication occurred more frequently with hydrocortisone than with placebo (4.3% vs. 1.0%). Other adverse events were similar in the two groups. CONCLUSIONS: In this trial involving preterm infants, hydrocortisone treatment starting on postnatal day 14 to 28 did not result in substantially higher survival without moderate or severe bronchopulmonary dysplasia than placebo. Survival without moderate or severe neurodevelopmental impairment did not differ substantially between the two groups. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01353313.).
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Displasia Broncopulmonar/prevenção & controle , Glucocorticoides/uso terapêutico , Hidrocortisona/uso terapêutico , Recém-Nascido Prematuro , Extubação , Displasia Broncopulmonar/epidemiologia , Método Duplo-Cego , Seguimentos , Glucocorticoides/administração & dosagem , Glucocorticoides/efeitos adversos , Humanos , Hidrocortisona/administração & dosagem , Hidrocortisona/efeitos adversos , Lactente Extremamente Prematuro , Recém-Nascido , Transtornos do Neurodesenvolvimento/epidemiologia , Transtornos do Neurodesenvolvimento/prevenção & controle , Oxigenoterapia , Respiração ArtificialRESUMO
BACKGROUND: Screening for pulmonary hypertension (PHT) is recommended in children with sickle cell disease (SCD). However, best approaches are poorly described. We examined the utility of PHT symptoms, echocardiogram (ECHO), N-terminal-pro hormone brain natriuretic peptide (NT-proBNP), and BNP to screen for PHT in the SCD pediatric population. METHODS: Children (8-18 years old) with SCD-HbSS and HbSthal° were prospectively included and underwent PHT screening. The screening consisted of a comprehensive PHT symptoms evaluation, ECHO measurement, and NT-proBNP and BNP levels. RESULTS: A total of 73 patients were included (mean age 12 ± 5.7 years; >80% on hydroxyurea), of which 37% had a symptom consistent with PHT, including exertional dyspnea (26.5%), fatigue (17.6%), palpitation (14.7%), and chest pain (10.3%). ECHO was obtained in 53 (72.6%) patients, with only ECHO of 48 patients included in the final analysis. Elevated ECHO peak tricuspid regurgitant jet velocity (TRV) >2.5 m/s or indirect findings to suggest PHT were seen in only two of 48 (4.2%). No significant differences were seen between those with and without PHT symptoms when compared for NT-proBNP, BNP, hemoglobin, pulmonary function testing, fractional exhaled nitric oxide, asthma, oxygen saturation, and sleep apnea. CONCLUSION: PHT symptoms are not consistent with ECHO, NT-proBNP nor BNP findings in children with SCD. PHT prevalence based on TRV was low in children on hydroxyurea, therefore screening may not be warranted for this group.
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Anemia Falciforme , Hipertensão Pulmonar , Criança , Humanos , Adolescente , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/epidemiologia , Hidroxiureia/uso terapêutico , Anemia Falciforme/epidemiologia , Fragmentos de Peptídeos , Testes de Função Respiratória , PrevalênciaRESUMO
BACKGROUND: Asthma in preschool children is poorly defined, proving to be a challenge for early detection. The Breathmobile Case Identification Survey (BCIS) has been shown to be a feasible screening tool in older SCD children and could be effective in younger children. We attempted to validate the BCIS as an asthma screening tool in preschool children with SCD. METHODS: This is a prospective, single-center study of 50 children aged 2-5 years with SCD. BCIS was administered to all patients and a pulmonologist blinded to the results evaluated patients for asthma. Demographic, clinical, and laboratory data were obtained to assess risk factors for asthma and acute chest syndrome in this population. RESULTS: Asthma prevalence (n = 3/50; 6%) was lower than atopic dermatitis (20%) and allergic rhinitis (32%). Sensitivity (100%), specificity (85%), positive predictive value (30%), and negative predictive value (100%) of the BCIS were high. Clinical demographics, atopic dermatitis, allergic rhinitis, asthma, viral respiratory infection, hematology parameters, sickle hemoglobin subtype, tobacco smoke exposure, and hydroxyurea were not different between patients with or without history of ACS, although eosinophil was significantly lower in the ACS group (p = 0.0093). All those with asthma had ACS, known viral respiratory infection resulting in hospitalization (3 RSV and 1 influenza), and HbSS (homozygous Hemoglobin SS) subtype. CONCLUSION: The BCIS is an effective asthma screening tool in preschool children with SCD. Asthma prevalence in young children with SCD is low. Previously known ACS risk factors were not seen, possibly from the beneficial effects of early life initiation of hydroxyurea.
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Anemia Falciforme , Asma , Dermatite Atópica , Rinite Alérgica , Humanos , Pré-Escolar , Idoso , Asma/diagnóstico , Asma/epidemiologia , Asma/etiologia , Hidroxiureia , Estudos Prospectivos , Anemia Falciforme/complicações , Anemia Falciforme/diagnóstico , Anemia Falciforme/epidemiologia , Rinite Alérgica/complicaçõesRESUMO
The radial spoke head protein 4 homolog A (RSPH4A) gene is one of more than 50 genes that cause Primary ciliary dyskinesia (PCD), a rare genetic ciliopathy. Genetic mutations in the RSPH4A gene alter an important protein structure involved in ciliary pathogenesis. Radial spoke proteins, such as RSPH4A, have been conserved across multiple species. In humans, ciliary function deficiency caused by RSPH4A pathogenic variants results in a clinical phenotype characterized by recurrent oto-sino-pulmonary infections. More than 30 pathogenic RSPH4A genetic variants have been associated with PCD. In Puerto Rican Hispanics, a founder mutation (RSPH4A (c.921+3_921+6delAAGT (intronic)) has been described. The spectrum of the RSPH4A PCD phenotype does not include laterality defects, which results in a challenging diagnosis. PCD diagnostic tools can combine transmission electron microscopy (TEM), nasal nitric oxide (nNO), High-Speed Video microscopy Analysis (HSVA), and immunofluorescence. The purpose of this review article is to provide a comprehensive overview of current knowledge about the RSPH4A gene in PCD, ranging from basic science to human clinical phenotype.
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Síndrome de Kartagener , Humanos , Síndrome de Kartagener/diagnóstico , Síndrome de Kartagener/genética , Cílios/metabolismo , Proteínas/metabolismo , Mutação , Axonema/metabolismo , Proteínas do Citoesqueleto/metabolismoRESUMO
BACKGROUND: Screening for obstructive sleep apnea (OSA) is recommended by current guidelines in children with sickle cell anemia (SCA), but no specific approach is described. The Pediatric Sleep Questionnaire (PSQ) is a validated detection tool for OSA in children. We assessed the utility of PSQ to screen for OSA in children with concomitant SCA and snoring. MATERIALS AND METHODS: A prospective study, in children 4 to 18 years old with SCA. Subjects were assessed for snoring and PSQ administered at the same visit. All children with snoring were then referred for polysomnography. RESULTS: A total of 106 subjects were screened. Habitual snoring prevalence was 51/106 (48.1%). In the snoring group, OSA was detected in 83.9% (apnea-hypopnea index [AHI] ≥1.0/h) and 22.6% (AHI ≥5.0/h), respectively. Sensitivity and specificity of PSQ in children with snoring was 46.2% and 20.0% (AHI ≥1.0/h), and 57.1% and 50.0% (AHI ≥5.0/h), respectively. Physician assessment for snoring had a high sensitivity of 70.3% but low specificity of 58.4% (AHI ≥1.0/h), and 87.5% and 41.5% (AHI ≥5.0/h), respectively. CONCLUSION: PSQ is a poor screening tool for detection of OSA in those children with SCA who snore. Physician assessment for snoring could however be an initial approach before polysomnography.
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Anemia Falciforme , Síndromes da Apneia do Sono , Apneia Obstrutiva do Sono , Adolescente , Anemia Falciforme/complicações , Anemia Falciforme/diagnóstico , Criança , Pré-Escolar , Humanos , Estudos Prospectivos , Síndromes da Apneia do Sono/diagnóstico , Síndromes da Apneia do Sono/epidemiologia , Síndromes da Apneia do Sono/etiologia , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/epidemiologia , Ronco/diagnóstico , Ronco/epidemiologia , Ronco/etiologiaRESUMO
Objective: To assess whether an asthma intervention program reduces treatment days outside the home among children with severe asthma receiving comprehensive care (CC) in our center.Methods: Between October 21, 2014 and September 28, 2016, children with severe asthma were randomized to receive CC alone (n = 29) or CC plus the asthma intervention program (n = 34) which involved collaboration with pharmacists and school nurses, motivational interviewing, and tracking the one-second forced expiratory volume at home. All patients were followed through March 31, 2017. Frequentist and Bayesian intent-to-treat analyses were performed.Results: The asthma intervention program doubled the telephone calls between the staff and families (753 vs 356 per 100 child years for the intervention group vs. control group; Rate Ratio [RR], 2.11 [95% confidence interval, 1.29-3.45]). Yet, we found no evidence that it reduced the composite number of days of healthcare outside home which includes: clinic visits, ED visits, and hospital admissions (1179 vs 958 per 100 child-years in the intervention group vs. control group; [RR], 1.23 [95% CI, 0.82-1.84]) or secondary outcomes which are individual components (clinic visits, ED visits, hospitalizations, PICU admissions and school absences; RR 1.15 - 2.30; p > 0.05). Bayesian analysis indicated a 67% probability that the intervention program increases total treatment days outside the home and only a 14% probability of a true decrease of >20% as originally hypothesized.Conclusion: A multi-component intervention program provided to children with severe asthma failed to reduce and may have increased days of healthcare outside home and school absenteeism.
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Asma/terapia , Adesão à Medicação , Absenteísmo , Adolescente , Instituições de Assistência Ambulatorial/estatística & dados numéricos , Asma/fisiopatologia , Criança , Pré-Escolar , Comunicação , Serviço Hospitalar de Emergência/estatística & dados numéricos , Feminino , Volume Expiratório Forçado , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Motivação , Equipe de Assistência ao Paciente , Avaliação de Programas e Projetos de Saúde , Melhoria de Qualidade , Testes de Função RespiratóriaRESUMO
Background: Asthma is a chronic airway disorder with variable/recurring symptoms, airflow obstruction, bronchial hyperresponsiveness, and an inflammation. The expert panel report of the National Heart Lung and Blood Institute recommends asthma screening in sickle cell disease (SCD); however, specific approach is not mentioned. We hypothesize that the breathmobile case identification survey (BCIS) is a valid asthma screening tool in children with SCD.Methods: This prospective, single-center study enrolled 129 SCD patients aged 5 to 18 years from March 2016 to March 2018. All patients completed BCIS, spirometry, and fractional exhaled nitric oxide (FeNO). A single pulmonologist blinded to the BCIS results evaluated patients for asthma.Results: Asthma prevalence was 41%. Male gender (60.4%; p = 0.041), allergic rhinitis (86.8%; p < 0.01), hydroxyurea usage (73.6%; p < 0.01), and family history of asthma (34%; p < 0.01) were higher but not self-reported parental asthma history, eczema, and tobacco smoke exposure in the asthma group compared to the nonasthma group. FEV1 (p = 0.003), FVC (p = 0.02), FEV1/FVC (p = 0.053), and FEF25-75% (p = 0.02) were lower in asthma. FeNO levels were comparable in both groups. The sensitivity, specificity, positive predictive value, and negative predictive value of the abbreviated BCIS were 67.3%, 90.8%, 83.3%, and 80.2% for asthma; and 82.1%, 90.8%, 76.7%, and 93.2% for persistent asthma, respectively. Persistent asthma patients had a trend of higher hydroxyurea use (82.8% vs. 58.3%; p = 0.049) and tobacco smoke exposure (55.2% vs. 29.2%; p = 0.057) compared to intermittent asthma.Conclusion: We have validated the BCIS to screen for asthma in SCD. Spirometry but not FeNO may support an asthma diagnosis.
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Anemia Falciforme/epidemiologia , Asma/diagnóstico , Asma/epidemiologia , Programas de Rastreamento/métodos , Adolescente , Fatores Etários , Criança , Pré-Escolar , Feminino , Humanos , Hidroxiureia/administração & dosagem , Masculino , Programas de Rastreamento/normas , Anamnese , Prevalência , Estudos Prospectivos , Testes de Função Respiratória , Rinite Alérgica/epidemiologia , Índice de Gravidade de Doença , Fatores Sexuais , Inquéritos e Questionários/normas , Poluição por Fumaça de Tabaco/estatística & dados numéricosRESUMO
BACKGROUND: Congenital central hypoventilation syndrome (CCHS) is a rare disorder characterized by respiratory system abnormalities, including alveolar hypoventilation and autonomic nervous system dysregulation. CCHS is associated with compromised brain development and neurocognitive functioning. Studies that evaluate cognitive skills in CCHS are limited, and no study has considered cognitive abilities in conjunction with psychosocial and adaptive functioning. Moreover, the roles of pertinent medical variables such as genetic characteristics are also important to consider in the context of neurocognitive functioning. METHODS: Seven participants with CCHS ranging in age from 1 to 20 years underwent neuropsychological evaluations in a clinic setting. RESULTS: Neurocognitive testing indicated borderline impaired neurocognitive skills, on average, as well as relative weaknesses in working memory. Important strengths, including good coping skills and relatively strong social skills, may serve as protective factors in this population. CONCLUSION: CCHS was associated with poor neurocognitive outcomes, especially with some polyalanine repeat expansion mutations (PARMS) genotype. These findings have important implications for individuals with CCHS as well as medical providers for this population.
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Hipoventilação , Apneia do Sono Tipo Central , Adolescente , Adulto , Criança , Pré-Escolar , Proteínas de Homeodomínio/genética , Humanos , Hipoventilação/congênito , Hipoventilação/genética , Lactente , Mutação , Apneia do Sono Tipo Central/diagnóstico , Apneia do Sono Tipo Central/genética , Fatores de Transcrição/genética , Adulto JovemRESUMO
OBJECTIVE: To assess the sustainability of the benefits relative to usual care of a medical home providing comprehensive care for high-risk children with medical complexity (≥2 hospitalizations or ≥1 pediatric intensive care unit [PICU] admission in the year before enrollment) after we made comprehensive care our standard practice and expanded the program. STUDY DESIGN: We conducted pre-post comparisons of the rate of children with serious illness (death, PICU admission, or >7-day hospitalization) and health-system costs observed after program expansion (March 2014-June 2015) to those during the clinical trial (March 2011-August 2013) for each of the trial's treatment groups (usual care, n = 96, and comprehensive care, n = 105; primary analyses), and among all children given comprehensive care (nPost-trial = 233, including trial usual care children who transitioned to comprehensive care post-trial and newly enrolled medically complex children, and nTrial = 105; secondary analyses). We also analyzed the findings for the trial patients as a 2-phase stepped-wedge study. RESULTS: In intent-to-treat analyses, rates of children with serious illness and costs were reduced or unchanged post-trial vs trial for the trial's usual care group (rate ratio [RR], 0.36; 95% CI, 0.20-0.64; cost ratio [CR], 0.68; 95% CI, 0.28-1.68), the trial's comprehensive care group (RR, 0.74; 95% CI, 0.39-1.41; CR, 0.67; 95% CI, 0.51-0.89), and among all children given comprehensive care (RR, 0.97; 95% CI, 0.61-1.52; CR, 0.75; 95% CI, 0.61-0.93). Conservative stepped-wedge analyses identified overall benefits with comprehensive care across both study periods (RR, 0.46; 95% CI, 0.30-0.72; CR, 0.64; 95% CI, 0.43-0.99). CONCLUSIONS: Major benefits of comprehensive care did not diminish with post-trial program expansion.
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Assistência Integral à Saúde , Cuidados Críticos , Estado Terminal , Custos de Cuidados de Saúde , Assistência Centrada no Paciente , Avaliação de Programas e Projetos de Saúde , Criança , Feminino , Hospitalização , Humanos , MasculinoRESUMO
The high sensitivity of chiroptical responses to conformational changes and supramolecular interactions has prompted an increasing interest in the development of chiroptical applications. However, prediction of and understanding the chiroptical responses of the necessary large systems may not be affordable for calculations at high levels of theory. In order to facilitate the development of chiroptical applications, methodologies capable of evaluating the chiroptical responses of large systems are necessary. The exciton chirality method has been extensively used for the interaction between two independent chromophores through the Davydov model. For systems presenting C2 or D2 symmetry, one can get the same results by applying the selection rules. In the present article, the analysis of the selection rules for systems with symmetries Cn and Dn with n = 3 and 4 is used to uncover the origin of their chiroptical responses. We foresee that the use of the Chiroptical Symmetry Analysis (CSA) for systems presenting the symmetries explored herein, as well as for systems presenting higher symmetries will serve as a useful tool for the development of chiroptical applications.
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Modelos Teóricos , Algoritmos , Dicroísmo CircularRESUMO
Despite the fact that transferability and chemistry go hand in hand, transferability studies in electronically excited states (EESs) are normally omitted, although these states are becoming extremely important in modern processes and applications. In this work, it is shown that this kind of studies can be used to understand how substituent effects can be modified in EESs. Thus, for example, the analysis of the carbonyl oxygen transferability in different HCO-R molecules allowed us to find that the nOâπCO* excitation can be used to break the π conjugation associated to the resonance substituent effect. Moreover, as a direct consequence, the oxygen transferability is enhanced in the first electronically excited state.
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A method based on a real space partitioning to measure the importance of Lewis structures is proposed in this work. A matrix containing diverse QTAIM atomic and diatomic properties endowed with significance within a Lewis structure framework is expanded in terms of what we call Lewis-structure matrices. Each of these matrices flawlessly describes an individual resonance structure and its associated linear expansion coefficient (Q-ALE coefficient) indicates the importance or convenience of the given Lewis structure. These coefficients were inspected looking at their evolution in a series of usual chemical issues. Among all the results, we find of interest that σ resonance structures in systems with π electrons are more important than normally expected, which justifies why the qualitative predictions arising from the application of the resonance model and the quantitative results based on QTAIM properties are sometimes discrepant. Likewise, we observe that the variation of the dielectric constant of the medium affects the π resonance to a greater extent than it does the σ one. Other interesting results in this manuscript are connected to homolytic dissociation of diatomic molecules, periodic trends in hydrogen compounds, and polarization of aromatic systems as a consequence of their interaction with electric fields and with diverse ions.
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Carboxylic acids, esters, secondary amides, and related molecules share a thermodynamic preference for the Z arrangement of their X[double bond, length as m-dash]C-Y-R moiety. This conformational predisposition is known as the Z effect and its most common explanation invokes the hyperconjugation from a Y lone pair to the σCX* orbital. In this work, we present clear topological evidence that hyperconjugation is not responsible for the Z preference. Diverse tools defined within the quantum chemical topology framework (such as, for example, atomic and electron localization function populations or the interacting quantum atoms energy decomposition) were used to analyse the evolution of formic acid from the E conformer towards the Z conformation. The results highlight the important role of the π resonance in the barrier between conformers and they also indicate that the hyperconjugative interaction lacks a leading role. Concretely, in an X[double bond, length as m-dash]C-Y-R structure, the XR interaction seems to be the key to understanding the preference for the Z arrangement of the moiety. Interestingly, our proposed explanation can be extended to a wide range of molecules presenting the same conformational preference, such as proteins or peptide nucleic acids.
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The theory of chemical bonding is underdeveloped in electronic excited states, even in small molecules. Fortunately, real space tools may be used to offer rich images of simple excitation processes, as is shown in this work. The statistics of electron populations, through a fruitful combination of electron distribution functions (EDFs) and domain averaged Fermi holes (DAFHs), was used to enlighten our chemical knowledge of a paradigmatic process: the n â π* excitation in formaldehyde. Interestingly, our results are perfectly compatible with an alternative perception of the electronic transition: the rotation of one averaged-electron in the oxygen lone pair. This topological model does not require inter-orbital jumps to explain the final electron distribution and, in our humble opinion, this fact makes it, to some extent, more realistic. Finally, other far-reaching conclusions emerge smoothly from our analysis: (i) the σ link may contribute less to the total bond order (as measured by the delocalization index) of a polar double bond than the π one; (ii) populating an antibonding orbital does not necessarily imply decreasing the bond order of its corresponding bond.
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The electron localization function, natural localized molecular orbitals, and the quantum theory of atoms in molecules have been used all together to analyze the bond electron density (BED) distribution of different hydrogen-containing compounds through the definition of atomic contributions to the bonding regions. A function, gAH , obtained from those contributions is analyzed along the second and third periods of the periodic table. It exhibits periodic trends typically assigned to the electronegativity (χ), and it is also sensitive to hybridization variations. This function also shows an interesting S shape with different χ-scales, Allred-Rochow's being the one exhibiting the best monotonical increase with regard to the BED taken by each atom of the bond. Therefore, we think this χ can be actually related to the BED distribution.
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BACKGROUND: Recent studies have demonstrated that respiratory syncytial virus (RSV) is a significant cause of morbidity and mortality in the elderly. The cellular mechanisms that determine the host's susceptibility and severity of the disease are not well understood. In this study, we sought a mouse model of human respiratory disease by studying the functional and cellular response to RSV in aged animals. METHODS: Aged BALB/c mice (>10 months of age) were infected with human RSV (strain A2) and compared with sham-infected mice. Clinical progress of the illness was monitored by daily assessment of weight changes and mortality. The animals were sacrificed four days postinfection. Lung pathology was obtained and viral titers were measured by plaque assay. Gene expression profiles were studied from lung tissue RNA using gene array. RESULTS: RSV produced significant clinical illness in aged mice as evidenced by a 15% weight loss and a 10% mortality rate. Lung pathology revealed inflammatory changes with a predominance of neutrophils and diffuse alveolar damage. Microarray analysis revealed variable profiles of gene activation/downregulation at day 4 postinfection. RSV infection resulted in a proinflammatory response. Surprisingly, some of the genes involved in antigen-processing pathway were downregulated, specifically, genes implicated in the major histocompatibility complex (MHC) class II pathway. CONCLUSIONS: Our findings indicate that RSV infection produces profound functional and cellular changes in aged mice thus resembling the human disease described in the elderly. Further studies will be needed to understand the cellular mechanisms involved in the host response to RSV in aged mice.
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Infecções por Vírus Respiratório Sincicial/genética , Infecções por Vírus Respiratório Sincicial/imunologia , Animais , Modelos Animais de Doenças , Regulação para Baixo/genética , Regulação para Baixo/imunologia , Feminino , Expressão Gênica/genética , Expressão Gênica/imunologia , Humanos , Pulmão/imunologia , Pulmão/patologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/imunologia , Infecções por Vírus Respiratório Sincicial/patologia , Vírus Sincicial Respiratório Humano/imunologia , Índice de Gravidade de DoençaRESUMO
We show that the use of the quantum theory of atoms in molecules (QTAIM) in electronically excited states allows expanding the knowledge that the molecular orbital (MO) framework provides about electronic rearrangements. Despite that historical prejudice seemed to preclude the use of QTAIM beyond the electronic ground state, this paper evidences that QTAIM is versatile enough to deal with excited states. As an example, the paradigmatic n â π* electronic transition of formaldehyde is analyzed. Using QTAIM, an energy partition of excited state energies into atomic and diatomic energies is carried out for the first time. This partition shows that upon electronic excitation the atoms of the CO bond experience a stabilization in their net energies, accompanied by a destabilization in their interaction, a fact which is in accordance with the idea of populating an antibonding π* MO. The associated C-O bond elongation in the nπ* state does not involve a change in the π atomic populations - as one would expect from a π* orbital - but in the σ ones. Moreover, it is also found that the nπ* state is characterized by a weaker C-O interaction energy in comparison to that in the electronic ground state. In order to strengthen this interaction, the electron-electron repulsion between C and O is reduced via a symmetry-breaking of the electron density, causing the C pyramidalization. A topological analysis based on the Laplacian of the electron density and on the electron localization function (ELF) reveals that the n â π* transition can be visualized as a rotation of 90° of the oxygen lone pairs.
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The theoretical study of Mn(salen) catalysts has been traditionally performed under the assumption that Mn(acacen') (acacen' = 3,3'-(ethane-1,2-diylbis(azanylylidene))bis(prop-1-en-olate)) is an appropriate surrogate for the larger Mn(salen) complexes. In this work, the geometry and the electronic structure of several Mn(salen) and Mn(acacen') model complexes were studied using Density Functional Theory (DFT) at diverse levels of approximation, with the aim of understanding the effects of truncation, metal oxidation, axial coordination, substitution on the aromatic rings of the salen ligand and chirality of the diimine bridge, as well as the choice of the density functional and basis set. To achieve this goal, geometric and structural data, obtained from these calculations, were subjected to Principal Component Analysis (PCA) and PCA with orthogonal rotation of the components (rPCA). The results show the choice of basis set to be of paramount importance, accounting for up to 30% of the variance in the data, while the differences between salen and acacen' complexes account for about 9% of the variance in the data, and are mostly related to the conformation of the salen/acacen' ligand around the metal centre. Variations in the spin state and oxidation state of the metal centre also account for large fractions of the total variance (up to 10% and 9%, respectively). Other effects, such as the nature of the diimine bridge or the presence of an alkyl substituent in the 3,3 and 5,5 positions of the aldehyde moiety, were found to be less important in terms of explaining the variance within the data set. A matrix of discriminants was compiled using the loadings of the principal and rotated components that best performed in the classification of the entries in the data. The scores obtained from its application to the data set were used as independent variables for devising linear models of different properties, with satisfactory prediction capabilities.
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The consequences of anchoring Mn(salen) catalysts onto a supporting material using one of the vacant positions of the metal center are tackled by studying several Mn(salen) complexes with different axial ligands attached. This is accomplished using Density Functional Theory at the X3LYP/Triple-ζ level of theory and the Atom In Molecules formalism. The results suggest that both Mn(salen) complexes and their oxo derivatives should lie in a triplet ground state. Also, the choice of the axial ligand bears a moderate effect on the energy involved in the oxidation of the former to oxo-Mn(salen) complexes, as well as in the stability of such complexes toward ligand removal by HCl. AIM analysis further suggests that the salen ligand acts as a "charge reservoir" for the metal center, with strong correlations being obtained between the charge of salen and the electron population donated by the axial ligand to the metal center. Moreover, the results suggest that the Mn atom in Mn(salen) complexes holds different hybridization of its valence orbitals depending on the type of axial ligand present in the system.
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IMPORTANCE: Patient-centered medical homes have not been shown to reduce adverse outcomes or costs in adults or children with chronic illness. OBJECTIVE: To assess whether an enhanced medical home providing comprehensive care prevents serious illness (death, intensive care unit [ICU] admission, or hospital stay >7 days) and/or reduces costs among children with chronic illness. DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial of high-risk children with chronic illness (≥3 emergency department visits, ≥2 hospitalizations, or ≥1 pediatric ICU admissions during previous year, and >50% estimated risk for hospitalization) treated at a high-risk clinic at the University of Texas, Houston, and randomized to comprehensive care (n = 105) or usual care (n = 96). Enrollment was between March 2011 and February 2013 (when predefined stopping rules for benefit were met) and outcome evaluations continued through August 31, 2013. INTERVENTIONS: Comprehensive care included treatment from primary care clinicians and specialists in the same clinic with multiple features to promote prompt effective care. Usual care was provided locally in private offices or faculty-supervised clinics without modification. MAIN OUTCOMES AND MEASURES: Primary outcome: children with a serious illness (death, ICU admission, or hospital stay >7 days), costs (health system perspective). Secondary outcomes: individual serious illnesses, medical services, Medicaid payments, and medical school revenues and costs. RESULTS: In an intent-to-treat analysis, comprehensive care decreased both the rate of children with a serious illness (10 per 100 child-years vs 22 for usual care; rate ratio [RR], 0.45 [95% CI, 0.28-0.73]), and total hospital and clinic costs ($16,523 vs $26,781 per child-year, respectively; cost ratio, 0.58 [95% CI, 0.38-0.88]). In analyses of net monetary benefit, the probability that comprehensive care was cost neutral or cost saving was 97%. Comprehensive care reduced (per 100 child-years) serious illnesses (16 vs 44 for usual care; RR, 0.33 [95% CI, 0.17-0.66]), emergency department visits (90 vs 190; RR, 0.48 [95% CI, 0.34-0.67]), hospitalizations (69 vs 131; RR, 0.51 [95% CI, 0.33-0.77]), pediatric ICU admissions (9 vs 26; RR, 0.35 [95% CI, 0.18-0.70]), and number of days in a hospital (276 vs 635; RR, 0.36 [95% CI, 0.19-0.67]). Medicaid payments were reduced by $6243 (95% CI, $1302-$11,678) per child-year. Medical school losses (costs minus revenues) increased by $6018 (95% CI, $5506-$6629) per child-year. CONCLUSIONS AND RELEVANCE: Among high-risk children with chronic illness, an enhanced medical home that provided comprehensive care to promote prompt effective care vs usual care reduced serious illnesses and costs. These findings from a single site of selected patients with a limited number of clinicians require study in larger, broader populations before conclusions about generalizability to other settings can be reached. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02128776.