Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 217
Filtrar
1.
Neuroimage Clin ; 42: 103590, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38513535

RESUMO

BACKGROUND: Apical ground-glass opacification (GGO) identified on CT angiography (CTA) performed for suspected acute stroke was developed in 2020 as a coronavirus-disease-2019 (COVID-19) diagnostic and prognostic biomarker in a retrospective study during the first wave of COVID-19. OBJECTIVE: To prospectively validate whether GGO on CTA performed for suspected acute stroke is a reliable COVID-19 diagnostic and prognostic biomarker and whether it is reliable for COVID-19 vaccinated patients. METHODS: In this prospective, pragmatic, national, multi-center validation study performed at 13 sites, we captured study data consecutively in patients undergoing CTA for suspected acute stroke from January-March 2021. Demographic and clinical features associated with stroke and COVID-19 were incorporated. The primary outcome was the likelihood of reverse-transcriptase-polymerase-chain-reaction swab-test-confirmed COVID-19 using the GGO biomarker. Secondary outcomes investigated were functional status at discharge and survival analyses at 30 and 90 days. Univariate and multivariable statistical analyses were employed. RESULTS: CTAs from 1,111 patients were analyzed, with apical GGO identified in 8.5 % during a period of high COVID-19 prevalence. GGO showed good inter-rater reliability (Fleiss κ = 0.77); and high COVID-19 specificity (93.7 %, 91.8-95.2) and negative predictive value (NPV; 97.8 %, 96.5-98.6). In subgroup analysis of vaccinated patients, GGO remained a good diagnostic biomarker (specificity 93.1 %, 89.8-95.5; NPV 99.7 %, 98.3-100.0). Patients with COVID-19 were more likely to have higher stroke score (NIHSS (mean +/- SD) 6.9 +/- 6.9, COVID-19 negative, 9.7 +/- 9.0, COVID-19 positive; p = 0.01), carotid occlusions (6.2 % negative, 14.9 % positive; p = 0.02), and larger infarcts on presentation CT (ASPECTS 9.4 +/- 1.5, COVID-19 negative, 8.6 +/- 2.4, COVID-19 positive; p = 0.00). After multivariable logistic regression, GGO (odds ratio 15.7, 6.2-40.1), myalgia (8.9, 2.1-38.2) and higher core body temperature (1.9, 1.1-3.2) were independent COVID-19 predictors. GGO was associated with worse functional outcome on discharge and worse survival after univariate analysis. However, after adjustment for factors including stroke severity, GGO was not independently predictive of functional outcome or mortality. CONCLUSION: Apical GGO on CTA performed for patients with suspected acute stroke is a reliable diagnostic biomarker for COVID-19, which in combination with clinical features may be useful in COVID-19 triage.


Assuntos
COVID-19 , Angiografia por Tomografia Computadorizada , Acidente Vascular Cerebral , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Biomarcadores , Angiografia por Tomografia Computadorizada/métodos , COVID-19/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Prognóstico , Estudos Prospectivos , SARS-CoV-2 , Acidente Vascular Cerebral/diagnóstico por imagem
2.
Sleep Med ; 101: 50-57, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36334501

RESUMO

OBJECTIVE: To explore the impact of the COVID-19 pandemic on the sleep-wake patterns of preschool children. METHODS: A cohort of preschoolers established before the COVID-19 pandemic was invited to participate in this study. Data including children's demographics, their own and parental sleep-wake patterns, physical activities, and screen time were collected through an online questionnaire from August to September 2020. A comparison was made on the collected data from the same cohort of children before and during the pandemic. RESULTS: The cohort which was established before the pandemic consisted of 3720 preschoolers. For this current study, 642 (17%) participated, and 497 (13%) children who fulfilled the eligibility criteria were included in the final analysis. They showed a delay in their bedtime and wake time on both weekdays and weekends with a 15-30 min increase in nocturnal sleep duration. However, with a reduction in nap time, the average daily sleep duration was shortened by 16.3 ± 64.3 min (p < 0.001) and 27.5 ± 72.9 min (p < 0.001) during weekdays and weekends, respectively. Screen time was increased while outdoor activity duration was decreased. Parental sleep/wake times were also delayed with an increase in sleep duration. Children's sleep habits were associated with screen time and parental sleep/wake patterns. CONCLUSION: Despite school suspension during the COVID-19 pandemic, preschoolers were not sleeping longer. Screen time and parental sleep/wake patterns were the major factors driving the preschoolers' sleep habits. Health education is required to control screen time in children and to promote sleep hygiene among all family members.


Assuntos
COVID-19 , Pandemias , Humanos , Pré-Escolar , COVID-19/epidemiologia , Sono , Higiene do Sono , Inquéritos e Questionários
3.
Ann R Coll Surg Engl ; 102(9): 737-743, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32820638

RESUMO

INTRODUCTION: Open thyroidectomy is the most common approach to thyroid surgery. However, 'scarless' (in the neck) endoscopic thyroidectomy, consisting of endoscopic and robotic surgery, is progressively being adopted for its perceived cosmetic benefits. This study aims to determine the patient's preferred surgical approach and to identify the factors that influence their decision. MATERIALS AND METHODS: A pilot study consisting of 100 patients with a surgical thyroid disorder were prospectively recruited from a single tertiary centre. An interviewer-administered survey was conducted. Demographic, socioeconomic status, scar perception and an adapted body image scale were evaluated to identify factors that shaped the patient's perception of the surgical approach. RESULTS: The mean age of participants was 54.5 ± 13.0 years; 72% were women and 87% Chinese. Of the 100 patients, 75 patients considered scarless endoscopic thyroidectomy as their preferred surgical approach while 25 patients opted for open thyroid surgery. Improvement in scar perception score between scarless endoscopic thyroidectomy and open thyroid surgery is associated with an increased willingness to choose scarless endoscopic thyroidectomy. The mean body image scale score was 6.9 ± 2.8, indicating no statistical difference between the surgical approaches. On multivariate analysis, improvement in scar perception score (odds ratio 3.38, 95% confidence interval 1.11-10.29) and having surgeon recommendation (odds ratio 6.38, 95% confidence interval 1.80-22.63) were independently associated with interest in scarless endoscopic thyroidectomy. CONCLUSION: Patients interest in undergoing scarless endoscopic thyroidectomy is driven by improved scar perception and surgeon's recommendation compared with open thyroid surgery.


Assuntos
Cicatriz/etiologia , Endoscopia/efeitos adversos , Preferência do Paciente/estatística & dados numéricos , Tireoidectomia/efeitos adversos , Atitude Frente a Saúde , Cicatriz/prevenção & controle , Cicatriz/psicologia , Estudos Transversais , Endoscopia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Preferência do Paciente/psicologia , Projetos Piloto , Estudos Prospectivos , Inquéritos e Questionários , Doenças da Glândula Tireoide/cirurgia , Tireoidectomia/métodos
5.
Rev. argent. dermatol ; 99(3): 41-50, set. 2018.
Artigo em Espanhol | LILACS | ID: biblio-977220

RESUMO

RESUMEN En este estudio del caso, los autores discuten la presentación de un varón de 56 años, con lepra lepromatosa multibacilar, localizado en un hospital del distrito de Trujillo. La biopsia de una de las lesiones, demostró infiltraciones difusas por macrófagos espumosos en toda su extensión; con la tinción de Ziehl - Neelsen se encuentran: bacilos ácido-alcohol resistentes sueltos o empaquetados en grupos, con índice bacilar: 6. La condición se manejó inicialmente en la comunidad como un "pénfigo ampolloso", sugiriendo que las barreras locales actualmente impiden la detección de la lepra en este sistema de atención primaria, en desarrollo. La lepra es una enfermedad multisistémica y el paciente demostró alteraciones neurológicas periféricas evidentes. Promover el conocimiento de estas manifestaciones sistémicas, evitará un retraso en el diagnóstico, a su vez disminuirá las complicaciones y eludirá la morbilidad a largo plazo. Los esfuerzos para optimizar los sistemas de detección, gestión, educación pública y profesional son esenciales, para impulsar la erradicación en estas poblaciones en riesgo.


SUMMARY In this case study, the authors discuss the presentation of a 56-year-old male in a hospital in the Trujillo district with lepromatous multibacillary leprosy. The biopsy of one of the lesions showed diffuse infiltrations by foamy macrophages in all its extension, with the stain of Ziehl - Neelsen bacilli acid resistant alcohol loose or packaged in groups, the bacilar index: 6. The condition was initially managed in the community as a "bullous pemphigus" that suggests that local barriers currently prevent the detection of leprosy in this developing primary care system. Leprosy is a multisystem disease and the patient demonstrated evident peripheral neurological alterations. Promoting the knowledge of these systemic manifestations will avoid a delay in the diagnosis, in turn will reduce complications and avoid long-term morbidity. Efforts to optimize detection systems, management and public and professional education are essential to promote eradication in these populations at risk.

6.
Cytopathology ; 29(3): 267-274, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29578257

RESUMO

OBJECTIVE: To evaluate the performance of an automated DNA-image-cytometry system as a tool to detect cervical carcinoma. METHODS: Of 384 liquid-based cervical cytology samples with available biopsy follow-up were analyzed by both the Imager System and a high-risk HPV test (Cobas). RESULTS: The sensitivity and specificity of Imager System for detecting biopsy proven high-grade squamous intraepithelial lesion (HSIL, cervical intraepithelial neoplasia [CIN]2-3) and carcinoma were 89.58% and 56.25%, respectively, compared to 97.22% and 23.33% of HPV test but additional HPV 16/18 genotyping increased the specificity to 69.58%. The sensitivity and specificity of the Imager System for predicting HSIL+ (CIN2-3+) lesions among atypical squamous cells of undetermined significance samples were 80.00% and 70.53%, respectively, compared to 100% and 11.58% of HPV test whilst the HPV 16/18 genotyping increased the specificity to 77.89%. Among atypical squamous cells-cannot exclude HSIL, the sensitivity and specificity of Imager System for predicting HSIL+ (CIN2-3+) lesions upon follow up were 82.86% and 33.33%%, respectively, compared to 97.14% and 4.76% of HPV test and the HPV 16/18 genotyping increased the specificity to 19.05%. Among low-grade squamous intraepithelial lesion cases, the sensitivity and specificity of the Imager System for predicting HSIL+ (CIN2-3+) lesions were 66.67% and 35.71%%, respectively, compared to 66.67% and 29.76% of HPV test while HPV 16/18 genotyping increased the specificity to 79.76%. The overall results of imager and high-risk HPV test agreed in 69.43% (268) of all samples. CONCLUSIONS: The automated imager system and HPV 16/18 genotyping can enhance the specificity of detecting HSIL+ (CIN2-3+) lesions.


Assuntos
Colo do Útero/patologia , DNA Viral/genética , Lesões Intraepiteliais Escamosas Cervicais/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Células Escamosas Atípicas do Colo do Útero/patologia , Células Escamosas Atípicas do Colo do Útero/virologia , Biópsia/métodos , Colo do Útero/virologia , Colposcopia/métodos , Feminino , Testes de DNA para Papilomavírus Humano/métodos , Papillomavirus Humano 16/genética , Papillomavirus Humano 18/genética , Humanos , Citometria por Imagem/métodos , Pessoa de Meia-Idade , Infecções por Papillomavirus/patologia , Infecções por Papillomavirus/virologia , Sensibilidade e Especificidade , Lesões Intraepiteliais Escamosas Cervicais/virologia , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/virologia , Esfregaço Vaginal/métodos , Adulto Jovem , Displasia do Colo do Útero/patologia , Displasia do Colo do Útero/virologia
7.
Hong Kong Med J ; 24(1): 48-55, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29302018

RESUMO

INTRODUCTION: Exotic pets are increasingly popular in Hong Kong and include fish, amphibians, reptiles, and arthropods. Some of these exotic animals are venomous and may cause injuries to and envenomation of their owners. The clinical experience of emergency physicians in the management of injuries and envenomation by these exotic animals is limited. We reviewed the clinical features and outcomes of injuries and envenomation by exotic pets recorded by the Hong Kong Poison Information Centre. METHODS: We retrospectively retrieved and reviewed cases of injuries and envenomation by exotic pets recorded by the Hong Kong Poison Information Centre from 1 July 2008 to 31 March 2017. RESULTS: There were 15 reported cases of injuries and envenomation by exotic pets during the study period, including snakebite (n=6), fish sting (n=4), scorpion sting (n=2), lizard bite (n=2), and turtle bite (n=1). There were two cases of major effects from the envenomation, seven cases with moderate effects, and six cases with mild effects. All major effects were related to venomous snakebites. There were no mortalities. CONCLUSION: All human injuries from exotic pets arose from reptiles, scorpions, and fish. All cases of major envenomation were inflicted by snakes.


Assuntos
Animais Exóticos , Mordeduras e Picadas/epidemiologia , Mordeduras e Picadas/etiologia , Ferimentos e Lesões/epidemiologia , Ferimentos e Lesões/etiologia , Adolescente , Adulto , Animais , Mordeduras e Picadas/prevenção & controle , Feminino , Peixes , Hong Kong/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Centros de Controle de Intoxicações/estatística & dados numéricos , Estudos Retrospectivos , Escorpiões , Serpentes , Ferimentos e Lesões/prevenção & controle , Adulto Jovem
8.
Hong Kong Med J ; 23(1): 13-8, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27909267

RESUMO

INTRODUCTION: There are two antivenoms that may be administered in Hong Kong following a bite by Trimeresurus albolabris: the green pit viper antivenom from the Thai Red Cross Society in Thailand and the Agkistrodon halys antivenom from the Shanghai Institute of Biological Products in China. Both are recommended by the Central Coordinating Committee of Accident and Emergency Services of the Hospital Authority for treating patients with a bite by Trimeresurus albolabris. The choice of which antivenom to use is based on physician preference. This study aimed to compare the relative efficacy of the two antivenoms. METHODS: This in-vitro experimental study was carried out by a wildlife conservation organisation and a regional hospital in Hong Kong. Human plasma from 40 adult health care worker volunteers was collected. The Trimeresurus albolabris venom was added to human plasma and the mixture was assayed after incubation with each antivenom (green pit viper and Agkistrodon halys) using saline as a control. Fibrinogen level and clotting time in both antivenom groups were studied. RESULTS: The mean fibrinogen level was elevated from 0 g/L to 2.86 g/L and 1.11 g/L after the addition of green pit viper antivenom and Agkistrodon halys antivenom, respectively. When mean clotting time was measured, the value was 6.70 minutes in the control, prolonged to more than 360 minutes by green pit viper antivenom and to 19.06 minutes by Agkistrodon halys antivenom. CONCLUSIONS: Green pit viper antivenom was superior to Agkistrodon halys antivenom in neutralisation of the thrombin-like and hypofibrinogenaemic activities of Trimeresurus albolabris venom.


Assuntos
Antivenenos/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Venenos de Crotalídeos/antagonistas & inibidores , Adulto , Testes de Coagulação Sanguínea , China , Venenos de Crotalídeos/intoxicação , Voluntários Saudáveis , Hong Kong , Humanos , Mordeduras de Serpentes/terapia , Tailândia , Fatores de Tempo
9.
Clin Exp Immunol ; 187(1): 113-123, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27667787

RESUMO

Tolerogenic dendritic cells (tolDC) are a new immunotherapeutic tool for the treatment of rheumatoid arthritis (RA) and other autoimmune disorders. We have established a method to generate stable tolDC by pharmacological modulation of human monocyte-derived DC. These tolDC exert potent pro-tolerogenic actions on CD4+ T cells. Lack of interleukin (IL)-12p70 production is a key immunoregulatory attribute of tolDC but does not explain their action fully. Here we show that tolDC express transforming growth factor (TGF)-ß1 at both mRNA and protein levels, and that expression of this immunoregulatory cytokine is significantly higher in tolDC than in mature monocyte-derived DC. By inhibiting TGF-ß1 signalling we demonstrate that tolDC regulate CD4+ T cell responses in a manner that is at least partly dependent upon this cytokine. Crucially, we also show that while there is no significant difference in expression of TGF-ßRII on CD4+ T cells from RA patients and healthy controls, RA patient CD4+ T cells are measurably less responsive to TGF-ß1 than healthy control CD4+ T cells [reduced TGF-ß-induced mothers against decapentaplegic homologue (Smad)2/3 phosphorylation, forkhead box protein 3 (FoxP3) expression and suppression of (IFN)-γ secretion]. However, CD4+ T cells from RA patients can, nonetheless, be regulated efficiently by tolDC in a TGF-ß1-dependent manner. This work is important for the design and development of future studies investigating the potential use of tolDC as a novel immunotherapy for the treatment of RA.


Assuntos
Artrite Reumatoide/terapia , Linfócitos T CD4-Positivos/imunologia , Células Dendríticas/imunologia , Tolerância Imunológica , Imunoterapia/métodos , Fator de Crescimento Transformador beta1/metabolismo , Artrite Reumatoide/imunologia , Células Cultivadas , Colecalciferol/farmacologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/transplante , Dexametasona/farmacologia , Fatores de Transcrição Forkhead/metabolismo , Humanos , Imunomodulação , Interleucina-12/genética , Interleucina-12/metabolismo , Ativação Linfocitária , Proteína Smad2/metabolismo
10.
Curr Oncol ; 23(4): e362-8, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27536185

RESUMO

PURPOSE: In the present study, we determined the association of pretreatment circulating neutrophils, monocytes, and lymphocytes with clinical outcomes after lung stereotactic body radiotherapy (sbrt). METHODS: All patients with primary lung cancer and with a complete blood count within 3 months of lung sbrt from 2005 to 2012 were included. Overall survival (os) was calculated using the Kaplan-Meier method. Factors associated with os were investigated using univariable and multivariable Cox proportional hazards regression. Fine-Gray competing risk regression was performed to test the association of the neutrophil:lymphocyte (nlr) and monocyte:lymphocyte (mlr) ratios with two types of failure: disease-related failure and death, and death unrelated to disease. RESULTS: Of the 299 sbrt patients identified, 122 were eligible for analysis. The median and range of the nlr and mlr were 3.0 (0.3-22.0) and 0.4 (0.1-1.9) respectively. On multivariable analysis, sex (p = 0.02), T stage (p = 0.04), and nlr (p < 0.01) were associated with os. On multivariable analysis, T stage (p < 0.01) and mlr (p < 0.01) were associated with disease-related failure; mlr (p = 0.03), nlr (p < 0.01), and sbrt dose of 48 Gy in 4 fractions (p = 0.03) and 54 Gy or 60 Gy in 3 fractions (p = 0.02) were associated with disease-unrelated death. Median survival was 4.3 years in the nlr≤3 group (95% confidence interval: 3.5 to not reached) and 2.5 years in the nlr>3 group (95% confidence interval: 1.7 to 4.8; p < 0.01). CONCLUSIONS: In lung sbrt patients, nlr and mlr are independently associated with os and disease-unrelated death. If validated, nlr and mlr could help to identify patients who would benefit most from sbrt.

11.
Nat Commun ; 7: 10401, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-26791253

RESUMO

Inorganic nanoparticles, stabilized by a passivating layer of organic molecules, form a versatile class of nanostructured materials with potential applications in material chemistry, nanoscale physics, nanomedicine and structural biology. While the structure of the nanoparticle core is often known to atomic precision, gaining precise structural and dynamical information on the organic layer poses a major challenge. Here we report a full assignment of (1)H and (13)C NMR shifts to all ligands of a water-soluble, atomically precise, 102-atom gold nanoparticle stabilized by 44 para-mercaptobenzoic acid ligands in solution, by using a combination of multidimensional NMR methods, density functional theory calculations and molecular dynamics simulations. Molecular dynamics simulations augment the data by giving information about the ligand disorder and visualization of possible distinct ligand conformations of the most dynamic ligands. The method demonstrated here opens a way to controllable strategies for functionalization of ligated nanoparticles for applications.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Ligantes , Espectroscopia de Ressonância Magnética , Simulação de Dinâmica Molecular
12.
ACS Nano ; 9(12): 11690-8, 2015 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-26530638

RESUMO

We report the assembly of gold nanoclusters by the nonthiolate ligand diglyme into discrete and dynamic assemblies. To understand this surprising phenomenon, the assembly of Au20(SC2H4Ph)15-diglyme into Au20(SC2H4Ph)15-diglyme-Au20(SC2H4Ph)15 is explored in detail. The assembly is examined by high-angle annular dark field scanning transmission electron microscopy, size exclusion chromatography, mass spectrometry, IR spectroscopy, and calorimetry. We establish a dissociation constant for dimer to monomer conversion of 20.4 µM. Theoretical models validated by transient absorption spectroscopy predict a low-spin monomer and a high-spin dimer, with assembly enabled through weak diglyme oxygen-gold interactions. Close spatial coupling allows electron delocalization between the nanoparticle cores. The resulting assemblies thus possess optical and electronic properties that emerge as a result of assembly.

13.
Eur J Clin Microbiol Infect Dis ; 34(9): 1827-32, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26071001

RESUMO

The automated high-throughput Abbott RealTime MTB real-time PCR assay has been recently launched for Mycobacterium tuberculosis complex (MTBC) clinical diagnosis. This study would like to evaluate its performance. We first compared its diagnostic performance with the Roche Cobas TaqMan MTB assay on 214 clinical respiratory specimens. Prospective analysis of a total 520 specimens was then performed to further evaluate the Abbott assay. The Abbott assay showed a lower limit of detection at 22.5 AFB/ml, which was more sensitive than the Cobas assay (167.5 AFB/ml). The two assays demonstrated a significant difference in diagnostic performance (McNemar's test; P = 0.0034), in which the Abbott assay presented significantly higher area under curve (AUC) than the Cobas assay (1.000 vs 0.880; P = 0.0002). The Abbott assay demonstrated extremely low PCR inhibition on clinical respiratory specimens. The automated Abbott assay required only very short manual handling time (0.5 h), which could help to improve the laboratory management. In the prospective analysis, the overall estimates for sensitivity and specificity of the Abbott assay were both 100 % among smear-positive specimens, whereas the smear-negative specimens were 96.7 and 96.1 %, respectively. No cross-reactivity with non-tuberculosis mycobacterial species was observed. The superiority in sensitivity of the Abbott assay for detecting MTBC in smear-negative specimens could further minimize the risk in MTBC false-negative detection. The new Abbott RealTime MTB assay has good diagnostic performance which can be a useful diagnostic tool for rapid MTBC detection in clinical laboratories.


Assuntos
Automação Laboratorial/métodos , Ensaios de Triagem em Larga Escala/métodos , Técnicas de Diagnóstico Molecular/métodos , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Pulmonar/diagnóstico , Automação Laboratorial/instrumentação , Diagnóstico Precoce , Ensaios de Triagem em Larga Escala/instrumentação , Humanos , Limite de Detecção , Técnicas de Diagnóstico Molecular/instrumentação , Estudos Prospectivos , Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e Especificidade , Tuberculose Pulmonar/microbiologia
14.
Chem Commun (Camb) ; 51(7): 1240-3, 2015 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-25472705

RESUMO

Gold nanoparticle catalysis of chemical transformations has emerged as a subject of intense interest over the past decade. In particular, Au25(SR)18 has emerged as a model catalyst. In an effort to investigate their potential as intact, homogeneous, unsupported catalysts, we have discovered that Au25(SR)18 clusters are not stable in oxidizing conditions reported for catalytic styrene oxidation. Further investigation suggests that the active catalytic species is an Au(I) species resulting from oxidative decomposition of the starting gold cluster. This conclusion appears independent of R-group on thiolate-ligated Au25(SR)18 clusters.

15.
ACS Comb Sci ; 17(1): 11-8, 2015 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-25459632

RESUMO

The effect of aqueous solvent concentration in the synthesis of water-soluble thiolate-protected gold nanoparticles (AuNPs) was investigated for 13 water-miscible solvents and three thiolate ligands (p-mercaptobenzoic acid, thiomalic acid, and glutathione). The results were analyzed by construction of heat maps that rank each reaction result for polydispersity. When solvents were organized in the heat map according to their Dimroth-Reichardt ET parameter (an approximate measure of polarity), two "hot spots" become apparent that are independent of the ligand used. We speculate that one hot spot may arise in part from the metal chelation or coordination ability of solvents that include diglyme, 1,2-dimethoxyethane, 1,4-dioxane, and tetrahydrofuran. The second hot spot arises at concentrations of alcohols including 2-propanol and 1-butanol that appear to selectively precipitate a growing product, presumably stopping its growth at a certain size. We observe some tightly dispersed products that appear novel. Overall, this study expands the number of tightly dispersed water-soluble AuNPs that can be directly synthesized.


Assuntos
Técnicas de Química Combinatória , Ouro/química , Nanopartículas Metálicas/química , Solventes/química , Compostos de Sulfidrila/química
16.
Man Ther ; 20(1): 130-3, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25150913

RESUMO

Kinesiology tape (KinTape) is a therapeutic tape without much understanding of its mechanism. KinTape claims to increase cutaneous stimulation, which facilitates motor unit firing, and consequently improves functional performance; however these, benefits could be due to placebo effects. This study investigated the true effects of KinTape by a deceptive, randomized, and controlled trial. Thirty healthy participants performed isokinetic testing of three taping conditions: true facilitative KinTape, sham KinTape, and no KinTape. The participants were blindfolded during the evaluation. Under the pretense of applying adhesive muscle sensors, KinTape was applied to their quadriceps in the first two conditions. Normalized peak torque, normalized total work, and time to peak torque were measured at two angular speeds (60°/s and 180°/s) and analyzed with one-way repeated measures ANOVA. Participants were successfully deceived and they were ignorant about KinTape. No significant differences were found between normalized peak torque, normalized total work, and time to peak torque at 60°/s or 180°/s (p = 0.31-0.99) between three taping conditions. The results showed that KinTape did not facilitate muscle performance in generating higher peak torque, yielding a greater total work, or inducing an earlier onset of peak torque. These findings suggest that previously reported muscle facilitatory effects using KinTape may be attributed to placebo effects.


Assuntos
Fita Atlética , Músculo Quadríceps/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Efeito Placebo , Torque , Adulto Jovem
18.
J Am Chem Soc ; 136(11): 4129-32, 2014 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-24588769

RESUMO

The Au102(p-MBA)44 cluster (p-MBA: para-mercaptobenzoic acid) is observed as a chiral compound comprised of achiral components in its single-crystal structure. So far the enantiomers observed in the crystal structure are not isolated, nor is the circular dichroism spectrum known. A chiral phase transfer method is presented which allows partial resolution of the enantiomers by the use of a chiral ammonium bromide, (-)-1R,2S-N-dodecyl-N-methylephedrinium bromide ((-)-DMEBr). At sufficiently low concentration of (-)-DMEBr, the phase transfer from water to chloroform is incomplete. Both the aqueous and organic phases show optical activity of near mirror image relationship. Differences in the spectra are ascribed to the formation of diastereomeric salts. At high concentrations of (-)-DMEBr, full phase transfer is observed. The organic phase, however, still displays optical activity. We assume that one of the diastereomers has very strong optical activity, which overrules the cancelation of the spectra with opposite sign. Comparison with computations further corroborates the experimental data and allows a provisional assignment of handedness of each fraction.

19.
Nanoscale ; 5(21): 10525-33, 2013 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-24057086

RESUMO

The absorption, distribution, metabolism and excretion (ADME) and pharmacokinetic (PK) properties of inorganic nanoparticles with hydrodynamic diameters between 2 and 20 nm are presently unpredictable. It is unclear whether unpredictable in vivo properties and effects arise from a subset of molecules in a nanomaterials preparation, or if the ADME/PK properties are ensemble properties of an entire preparation. Here we characterize the ADME/PK properties of atomically precise preparations of ligand protected gold nanoclusters in a murine model system. We constructed atomistic models and tested in vivo properties for five well defined compounds, based on crystallographically resolved Au25(SR)18 and Au102(SR)44 nanoclusters with different (SR) ligand shells. To rationalize unexpected distribution and excretion properties observed for several clusters in this study and others, we defined a set of atomistic structure-activity relationships (SAR) for nanoparticles, which includes previously investigated parameters such as particle hydrodynamic diameter and net charge, and new parameters such as hydrophobic surface area and surface charge density. Overall we find that small changes in particle formulation can provoke dramatic yet potentially predictable changes in ADME/PK.


Assuntos
Nanopartículas/metabolismo , Animais , Ouro/química , Camundongos , Modelos Animais , Nanopartículas/química , Relação Estrutura-Atividade , Propriedades de Superfície , Distribuição Tecidual
20.
J Clin Pharm Ther ; 38(5): 405-15, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23815285

RESUMO

WHAT IS KNOWN AND OBJECTIVES: A recently published large, long-term randomized controlled trial (RCT) brought into question the safety of dutasteride after a significantly increased risk of 'cardiac failure' was noted in the dutasteride arm of the trial compared with placebo. Our objective was to perform a meta-analysis to assess the risk of cardiovascular adverse events with the use of dutasteride for the prevention or treatment of prostatic disease. METHODS: We searched MEDLINE and EMBASE, unpublished articles identified through FDA/EMEA websites, study registers of pharmaceutical companies and reference lists of articles. Parallel-group, randomized controlled trials where men received dutasteride for the prevention of prostate cancer or treatment of prostatic hyperplasia against any comparator intervention were included. Heart failure was the primary outcome of interest but we also looked at myocardial infarction and stroke. Fixed-effect meta-analysis of pooled relative risk (RR) ratios of adverse effect outcomes was conducted. RESULTS AND DISCUSSION: In all, 12 RCTs were included in the meta-analysis after detailed screening of 564 citations. The total number of participants was 18,802, and study duration ranged from 6 to 208 weeks. Only two trials provided details on adequate allocation concealment, whereas all the trials stated they were double blind in nature. Dutasteride was not associated with a statistically significant increased risk of heart failure (RR 1·05; 95% confidence interval [CI], 0·71-1·57, I(2) = 20%), myocardial infarction (RR 1·00; 95% CI 0·77-1·30, I(2) = 0%) and stroke (RR, 1·20; 95% CI 0·88-1·64, I(2) = 0%) as compared to controls. WHAT IS NEW AND CONCLUSION: We did not find consistent evidence of a significant association between dutasteride therapy and the risk of cardiovascular adverse events.


Assuntos
Inibidores de 5-alfa Redutase/efeitos adversos , Inibidores de 5-alfa Redutase/uso terapêutico , Azasteroides/efeitos adversos , Azasteroides/uso terapêutico , Doenças Cardiovasculares/induzido quimicamente , Método Duplo-Cego , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Dutasterida , Humanos , Masculino , Doenças Prostáticas/tratamento farmacológico , Ensaios Clínicos Controlados Aleatórios como Assunto , Risco
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA