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1.
Cell ; 178(5): 1057-1071.e11, 2019 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-31442400

RESUMO

The Zika epidemic in the Americas has challenged surveillance and control. As the epidemic appears to be waning, it is unclear whether transmission is still ongoing, which is exacerbated by discrepancies in reporting. To uncover locations with lingering outbreaks, we investigated travel-associated Zika cases to identify transmission not captured by reporting. We uncovered an unreported outbreak in Cuba during 2017, a year after peak transmission in neighboring islands. By sequencing Zika virus, we show that the establishment of the virus was delayed by a year and that the ensuing outbreak was sparked by long-lived lineages of Zika virus from other Caribbean islands. Our data suggest that, although mosquito control in Cuba may initially have been effective at mitigating Zika virus transmission, such measures need to be maintained to be effective. Our study highlights how Zika virus may still be "silently" spreading and provides a framework for understanding outbreak dynamics. VIDEO ABSTRACT.


Assuntos
Epidemias , Genômica/métodos , Infecção por Zika virus/epidemiologia , Aedes/virologia , Animais , Cuba/epidemiologia , Humanos , Incidência , Controle de Mosquitos , Filogenia , RNA Viral/química , RNA Viral/metabolismo , Análise de Sequência de RNA , Viagem , Índias Ocidentais/epidemiologia , Zika virus/classificação , Zika virus/genética , Zika virus/isolamento & purificação , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
2.
Am J Otolaryngol ; 45(3): 104243, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38442460

RESUMO

PURPOSE: To compare human papillomavirus (HPV) testing, prevalence, and association with prognosis between head and neck squamous cell carcinoma (HNSCC) subsites. MATERIALS AND METHODS: This study utilized the National Cancer Database (NCDB) to identify patients diagnosed with HNSCC between 2010 and 2017. Rates of HPV testing, HPV-positivity, and changes in these rates over time were measured by subsite. The impact of HPV-positivity on overall survival across six head and neck subsites was assessed using multivariable-adjusted Cox proportional hazards analysis. RESULTS: A total of 121,550 patients were included. Of this cohort, 87,575 (72.1%) were tested for HPV, with the oropharynx (55,049/64,158; 85.8%) displaying the highest rates of testing and the sinonasal tract (1519/2853; 53.2%) displaying the lowest testing rates. Of the 86,136 with a definitive result, 46,878 (54.4%) were HPV-positive, with the oropharynx (40,313/54,205; 74.4%) displaying the highest rates of HPV-positivity and the oral cavity (1818/11,505; 15.8%) displaying the lowest. HPV-positive malignancy was associated with significantly improved adjusted overall survival in the oropharynx (HR = 0.42 [95% CI: 0.43-0.47]), oral cavity (HR = 0.86 [95% CI: 0.79-0.95]), sinonasal tract (HR = 0.63 [95% CI: 0.48-0.83]), larynx (HR = 0.78 [95% CI: 0.71-0.87]), and hypopharynx (HR = 0.56 [95% CI: 0.48-0.66]), but not the nasopharynx (HR = 0.93 [95% CI: 0.77-1.14]). CONCLUSION: HPV testing rates were significantly lower in non-oropharyngeal subsites. This is relevant as HPV-associated disease displayed significantly improved overall survival in both the oropharynx and four of five non-oropharyngeal subsites. While validation with prospective studies is necessary, these findings may warrant HPV testing in all HNSCC subsites.


Assuntos
Neoplasias de Cabeça e Pescoço , Infecções por Papillomavirus , Carcinoma de Células Escamosas de Cabeça e Pescoço , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Bases de Dados Factuais , Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/virologia , Papillomavirus Humano/isolamento & purificação , Infecções por Papillomavirus/diagnóstico , Prevalência , Prognóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço/virologia , Taxa de Sobrevida , Estados Unidos/epidemiologia
3.
Langmuir ; 39(9): 3320-3331, 2023 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-36802616

RESUMO

Cell responses to external radiofrequencies (RF) are a fundamental problem of much scientific research, clinical applications, and even daily lives surrounded by wireless communication hardware. In this work, we report an unexpected observation that the cell membrane can oscillate at the nanometer scale in phase with the external RF radiation from kHz to GHz. By analyzing the oscillation modes, we reveal the mechanism behind the membrane oscillation resonance, membrane blebbing, the resulting cell death, and the selectivity of plasma-based cancer treatment based on the difference in the membrane's natural frequencies among cell lines. Therefore, a selectivity of treatment can be achieved by aiming at the natural frequency of the target cell line to focus the membrane damage on the cancer cells and avoid normal tissues nearby. This gives a promising cancer therapy that is especially effective in the mixing lesion of the cancer cells and normal cells such as glioblastoma where surgical removal is not applicable. Along with these new phenomena, this work provides a general understanding of the cell coupling with RF radiation from the externally stimulated membrane behavior to the cell apoptosis and necrosis.


Assuntos
Campos Eletromagnéticos , Ondas de Rádio , Membrana Celular , Linhagem Celular
4.
Soft Matter ; 19(3): 451-467, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36530043

RESUMO

Atomic Force Microscopy (AFM) force-distance (FD) experiments have emerged as an attractive alternative to traditional micro-rheology measurement techniques owing to their versatility of use in materials of a wide range of mechanical properties. Here, we show that the range of time dependent behaviour which can reliably be resolved from the typical method of FD inversion (fitting constitutive FD relations to FD data) is inherently restricted by the experimental parameters: sampling frequency, experiment length, and strain rate. Specifically, we demonstrate that violating these restrictions can result in errors in the values of the parameters of the complex modulus. In the case of complex materials, such as cells, whose behaviour is not specifically understood a priori, the physical sensibility of these parameters cannot be assessed and may lead to falsely attributing a physical phenomenon to an artifact of the violation of these restrictions. We use arguments from information theory to understand the nature of these inconsistencies as well as devise limits on the range of mechanical parameters which can be reliably obtained from FD experiments. The results further demonstrate that the nature of these restrictions depends on the domain (time or frequency) used in the inversion process, with the time domain being far more restrictive than the frequency domain. Finally, we demonstrate how to use these restrictions to better design FD experiments to target specific timescales of a material's behaviour through our analysis of a polydimethylsiloxane (PDMS) polymer sample.

5.
Nature ; 546(7658): 401-405, 2017 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-28538723

RESUMO

Zika virus (ZIKV) is causing an unprecedented epidemic linked to severe congenital abnormalities. In July 2016, mosquito-borne ZIKV transmission was reported in the continental United States; since then, hundreds of locally acquired infections have been reported in Florida. To gain insights into the timing, source, and likely route(s) of ZIKV introduction, we tracked the virus from its first detection in Florida by sequencing ZIKV genomes from infected patients and Aedes aegypti mosquitoes. We show that at least 4 introductions, but potentially as many as 40, contributed to the outbreak in Florida and that local transmission is likely to have started in the spring of 2016-several months before its initial detection. By analysing surveillance and genetic data, we show that ZIKV moved among transmission zones in Miami. Our analyses show that most introductions were linked to the Caribbean, a finding corroborated by the high incidence rates and traffic volumes from the region into the Miami area. Our study provides an understanding of how ZIKV initiates transmission in new regions.


Assuntos
Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologia , Zika virus/genética , Aedes/virologia , Animais , Região do Caribe/epidemiologia , Surtos de Doenças/estatística & dados numéricos , Feminino , Florida/epidemiologia , Genoma Viral/genética , Humanos , Incidência , Epidemiologia Molecular , Mosquitos Vetores/virologia , Zika virus/isolamento & purificação , Infecção por Zika virus/transmissão
6.
Nature ; 546(7658): 411-415, 2017 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-28538734

RESUMO

Although the recent Zika virus (ZIKV) epidemic in the Americas and its link to birth defects have attracted a great deal of attention, much remains unknown about ZIKV disease epidemiology and ZIKV evolution, in part owing to a lack of genomic data. Here we address this gap in knowledge by using multiple sequencing approaches to generate 110 ZIKV genomes from clinical and mosquito samples from 10 countries and territories, greatly expanding the observed viral genetic diversity from this outbreak. We analysed the timing and patterns of introductions into distinct geographic regions; our phylogenetic evidence suggests rapid expansion of the outbreak in Brazil and multiple introductions of outbreak strains into Puerto Rico, Honduras, Colombia, other Caribbean islands, and the continental United States. We find that ZIKV circulated undetected in multiple regions for many months before the first locally transmitted cases were confirmed, highlighting the importance of surveillance of viral infections. We identify mutations with possible functional implications for ZIKV biology and pathogenesis, as well as those that might be relevant to the effectiveness of diagnostic tests.


Assuntos
Filogenia , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia , Zika virus/genética , Zika virus/isolamento & purificação , Animais , Brasil/epidemiologia , Colômbia/epidemiologia , Culicidae/virologia , Surtos de Doenças/estatística & dados numéricos , Genoma Viral/genética , Mapeamento Geográfico , Honduras/epidemiologia , Humanos , Metagenoma/genética , Epidemiologia Molecular , Mosquitos Vetores/virologia , Mutação , Vigilância em Saúde Pública , Porto Rico/epidemiologia , Estados Unidos/epidemiologia , Zika virus/classificação , Zika virus/patogenicidade , Infecção por Zika virus/diagnóstico , Infecção por Zika virus/epidemiologia
7.
Lancet Oncol ; 22(5): 727-736, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33862002

RESUMO

BACKGROUND: Randomised, controlled trials and meta-analyses have shown the survival benefit of concomitant chemoradiotherapy or hyperfractionated radiotherapy in the treatment of locally advanced head and neck cancer. However, the relative efficacy of these treatments is unknown. We aimed to determine whether one treatment was superior to the other. METHODS: We did a frequentist network meta-analysis based on individual patient data of meta-analyses evaluating the role of chemotherapy (Meta-Analysis of Chemotherapy in Head and Neck Cancer [MACH-NC]) and of altered fractionation radiotherapy (Meta-Analysis of Radiotherapy in Carcinomas of Head and Neck [MARCH]). Randomised, controlled trials that enrolled patients with non-metastatic head and neck squamous cell cancer between Jan 1, 1980, and Dec 31, 2016, were included. We used a two-step random-effects approach, and the log-rank test, stratified by trial to compare treatments, with locoregional therapy as the reference. Overall survival was the primary endpoint. The global Cochran Q statistic was used to assess homogeneity and consistency and P score to rank treatments (higher scores indicate more effective therapies). FINDINGS: 115 randomised, controlled trials, which enrolled patients between Jan 1, 1980, and April 30, 2012, yielded 154 comparisons (28 978 patients with 19 253 deaths and 20 579 progression events). Treatments were grouped into 16 modalities, for which 35 types of direct comparisons were available. Median follow-up based on all trials was 6·6 years (IQR 5·0-9·4). Hyperfractionated radiotherapy with concomitant chemotherapy (HFCRT) was ranked as the best treatment for overall survival (P score 97%; hazard ratio 0·63 [95% CI 0·51-0·77] compared with locoregional therapy). The hazard ratio of HFCRT compared with locoregional therapy with concomitant chemoradiotherapy with platinum-based chemotherapy (CLRTP) was 0·82 (95% CI 0·66-1·01) for overall survival. The superiority of HFCRT was robust to sensitivity analyses. Three other modalities of treatment had a better P score, but not a significantly better HR, for overall survival than CLRTP (P score 78%): induction chemotherapy with taxane, cisplatin, and fluorouracil followed by locoregional therapy (ICTaxPF-LRT; 89%), accelerated radiotherapy with concomitant chemotherapy (82%), and ICTaxPF followed by CLRT (80%). INTERPRETATION: The results of this network meta-analysis suggest that further intensifying chemoradiotherapy, using HFCRT or ICTaxPF-CLRT, could improve outcomes over chemoradiotherapy for the treatment of locally advanced head and neck cancer. FUNDINGS: French Institut National du Cancer, French Ligue Nationale Contre le Cancer, and Fondation ARC.


Assuntos
Quimiorradioterapia , Neoplasias de Cabeça e Pescoço/terapia , Metanálise em Rede , Fracionamento da Dose de Radiação , Feminino , Neoplasias de Cabeça e Pescoço/mortalidade , Humanos , Masculino
8.
Oncologist ; 26(6): 504-513, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33675133

RESUMO

BACKGROUND: Treatment of human papillomavirus-related oropharyngeal squamous cell carcinoma (HPVOPC) results in unprecedented high survival rates but possibly unnecessary toxicity. We hypothesized that upfront surgery and neck dissection followed by reduced-dose adjuvant therapy for early and intermediate HPVOPC would ultimately result in equivalent progression-free survival (PFS) and overall survival while reducing toxicity. METHODS: This study was a nonrandomized phase II trial for early-stage HPVOPC treated with transoral robotic surgery (TORS) followed by reduced-dose radiotherapy. Patients with previously untreated p16-positive HPVOPC and <20 pack years' smoking history were enrolled. After robotic surgery, patients were assigned to group 1 (no poor risk features; surveillance), group 2 (intermediate pathologic risk factors [perineural invasion, lymphovascular invasion]; 50-Gy radiotherapy), or group 3 (poor prognostic pathologic factors [extranodal extension [ENE], more than three positive lymph nodes and positive margin]; concurrent 56-Gy chemoradiotherapy with weekly cisplatin). RESULTS: Fifty-four patients were evaluable; there were 25 in group 1, 15 in group 2, and 14 in group 3. Median follow-up was 43.9 months (9.6-75.8). Disease-specific survival was 98.1%, and PFS was 90.7%. PFS probability via Kaplan-Meier was 91.3% for group 1, 86.7% for group 2, and 93.3% for group 3. There were five locoregional failures (LRFs), including one distant metastasis and one contralateral second primary. Average time to LRF was 18.9 months (9.6-59.0); four LRFs were successfully salvaged, and the patients remain disease free (11.0-42.7 months); one subject remains alive with disease. CONCLUSION: The results indicate that upfront surgery with neck dissection with reduced-dose radiation for T1-2, N1 stage (by the eighth edition American Joint Committee on Cancer staging manual) HPVOPC results in favorable survival with excellent function in this population. These results support radiation dose reduction after TORS as a de-escalation strategy in HPVOPC. IMPLICATIONS FOR PRACTICE: Transoral robotic surgery can provide a safe platform for de-escalation in carefully selected patients with early-stage human papillomavirus-related oropharyngeal cancer. In this clinical trial, disease-specific survival was 100%, over 90% of the cohort had a reduction of therapy from standard of care with excellent functional results, and the five patients with observed locoregional failures were successfully salvaged.


Assuntos
Alphapapillomavirus , Carcinoma de Células Escamosas , Neoplasias Orofaríngeas , Infecções por Papillomavirus , Procedimentos Cirúrgicos Robóticos , Carcinoma de Células Escamosas/patologia , Humanos , Estadiamento de Neoplasias , Neoplasias Orofaríngeas/tratamento farmacológico , Neoplasias Orofaríngeas/radioterapia , Neoplasias Orofaríngeas/cirurgia , Papillomaviridae , Infecções por Papillomavirus/patologia , Síndrome de Resposta Inflamatória Sistêmica
9.
J Endocrinol Invest ; 43(3): 369-379, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31621051

RESUMO

PURPOSE: There are cognitive changes in primary hyperparathyroidism (PHPT) that improve with parathyroidectomy, but the mechanism of cognitive dysfunction has not been delineated. We assessed if cerebrovascular function is impaired in PHPT, improves post-parathyroidectomy and is associated with PTH level and cognitive dysfunction. METHODS: This is an observational study of 43 patients with mild hypercalcemic or normocalcemic PHPT or goiter. At baseline, cerebrovascular function (dynamic cerebral autoregulation and vasomotor reactivity) by transcranial Doppler and neuropsychological function were compared between all three groups. A subset underwent parathyroidectomy or thyroidectomy, and was compared 6 months post-operatively. RESULTS: Mean cerebrovascular and neuropsychological function was normal and no worse in PHPT compared to controls preoperatively. Higher PTH was associated with worse intracerebral autoregulation (r = - 0.43, p = 0.02) and worse cognitive performance on some tests. Post-parathyroidectomy, mood improved significantly, but changes did not differ compared to those having thyroidectomy (p = 0.84). There was no consistent improvement in cognition or change in vascular function in either surgical group. CONCLUSIONS: Although higher PTH was associated with worse intracerebral autoregulation, cerebrovascular function, cognition and mood were normal in mild PHPT. PTX did not improve vascular or cognitive function. The observed improvement in mood cannot be clearly attributed to PTX. Notwithstanding the small sample size, the results do not support changing current criteria for parathyroidectomy to include cognitive complaints. However, the associations between PTH, cognition and cerebral autoregulation merit future studies in those with more severe hyperparathyroidism.


Assuntos
Circulação Cerebrovascular/fisiologia , Cognição/fisiologia , Hiperparatireoidismo Primário/cirurgia , Artéria Cerebral Média/diagnóstico por imagem , Paratireoidectomia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Hiperparatireoidismo Primário/diagnóstico por imagem , Hiperparatireoidismo Primário/psicologia , Pessoa de Meia-Idade , Testes Neuropsicológicos , Resultado do Tratamento
10.
Acta Neurochir Suppl ; 127: 149-153, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31407076

RESUMO

BACKGROUND: Early identification of vasospasm prior to symptom onset would allow prevention of delayed cerebral ischemia (DCI) in aneurysmal subarachnoid hemorrhage (aSAH). Dynamic cerebral autoregulation (DCA) is a noninvasive means of assessing cerebral blood flow regulation by determining independence of low-frequency temporal oscillations of systemic blood pressure (BP) and cerebral blood flow velocities (CBFV). METHODS: Eight SAH patients underwent prospectively a median of 7 DCA assessments consisting of continuous measurements of BCFV and BP. Transfer function analysis was applied to calculate average phase shift (PS) in low (0.07-0.2 Hz) frequency range for each hemisphere as continuous measure of DCA. Lower PS indicated poorer regulatory response. DCI was defined as a 2-point decrease in Glasgow Coma Score and/or infarction on CT. RESULTS: Three subjects developed symptomatic vasospasm with median time-to-DCI of 9 days. DCI was significantly associated with lower PS over the entire recording period (Wald = 4.28; p = 0.039). Additionally, there was a significant change in PS over different recording periods after adjusting for DCI (Wald = 15.66; p = 0.001); particularly, a significantly lower mean PS day 3-5 after bleed (14.22 vs 27.51; p = 0.05). CONCLUSIONS: DCA might be useful for early detection of symptomatic vasospasm. A larger cohort study of SAH patients is currently underway.


Assuntos
Isquemia Encefálica , Hemorragia Subaracnóidea , Vasoespasmo Intracraniano , Estudos de Coortes , Homeostase , Humanos
11.
Occup Med (Lond) ; 70(3): 162-168, 2020 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-32040153

RESUMO

BACKGROUND: Pre-employment psychological screening to detect psychological vulnerability is common amongst emergency service organizations worldwide, yet the evidence for its ability to predict poor mental health outcomes is limited with published studies looking at post-recruitment research data rather than data collected by the organizations themselves. AIMS: The present study sought to investigate the ability of pre-employment screening to predict later psychological injury-related absenteeism amongst police officers. METHODS: A nested case-control study using prospective data was conducted. One hundred and fifty police officers with a liability-accepted psychological injury were matched to a control group of 150 psychologically healthy officers. Conditional logistic regression was used to examine associations between Minnesota Multiphasic Personality Inventory-2 (MMPI-2) scales measuring factors research has shown to predict psychological injury (Neuroticism, Psychoticism, Introversion, Disconstraint and Aggressiveness) and psychopathology (Depression, Anxiety and post-traumatic stress disorder [PTSD]) with subsequent psychological injury. RESULTS: Contrary to expectations, we were unable to demonstrate any association between validated pre-employment measures of personality and psychopathology with mental health outcomes amongst newly recruited police officers over a 7-year follow-up. CONCLUSIONS: Other measures may be better able to predict future mental health problems in police recruits.


Assuntos
Transtornos Mentais/psicologia , Doenças Profissionais/psicologia , Polícia/psicologia , Austrália , Estudos de Casos e Controles , Emprego/psicologia , Feminino , Humanos , MMPI , Masculino , Transtornos Mentais/diagnóstico , Determinação da Personalidade , Estudos Prospectivos , Licença Médica/estatística & dados numéricos
12.
J Emerg Med ; 59(6): 872-883, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32972788

RESUMO

BACKGROUND: The purpose of this study was to evaluate prehospital and emergency department (ED) interventions and outcomes of patients who received prehospital naloxone for a suspected opioid overdose. OBJECTIVES: The primary objective was to evaluate if the individual dose, individual route, total dose, number of prehospital naloxone administrations, or occurrence of a prehospital adverse event (AE) were associated with the occurrence of AEs in the ED. Secondary objectives included a subset analysis of patients who received additional naloxone while in the ED, or were admitted to an intensive care or step-down unit (ICU). METHODS: This was a retrospective, observational chart review of adult patients who received prehospital naloxone and were transported by ambulance to a suburban academic tertiary care center between 2014 and 2017. Descriptive, univariate, and multivariate statistics were used, with p < 0.05 indicating significance. RESULTS: There were 513 patients included in the analysis, with a median age of 29 years, and median total prehospital naloxone dose of 2 mg. An increasing number of prehospital naloxone doses, an occurrence of a prehospital AE, and a route of administration other than intranasally for the first dose of prehospital naloxone were significantly associated with an increased likelihood of an ED AE. Patients who received < 2 mg of prehospital naloxone had the least likelihood of being admitted to an ICU, whereas patients who received at least 6 mg had a dramatically increased likelihood of ICU admission. CONCLUSIONS: Our results suggest that an increasing number of prehospital naloxone doses was significantly associated with an increased likelihood of an ED adverse event.


Assuntos
Overdose de Drogas , Serviços Médicos de Emergência , Adulto , Overdose de Drogas/tratamento farmacológico , Serviço Hospitalar de Emergência , Humanos , Naloxona/uso terapêutico , Antagonistas de Entorpecentes/efeitos adversos , Estudos Retrospectivos
13.
Anal Chem ; 91(18): 11952-11962, 2019 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-31450886

RESUMO

We report on separations of ion isotopologues and isotopomers using ultrahigh-resolution traveling wave-based Structures for Lossless Ion Manipulations with serpentine ultralong path and extended routing ion mobility spectrometry coupled to mass spectrometry (SLIM SUPER IMS-MS). Mobility separations of ions from the naturally occurring ion isotopic envelopes (e.g., [M], [M+1], [M+2], ... ions) showed the first and second isotopic peaks (i.e., [M+1] and [M+2]) for various tetraalkylammonium ions could be resolved from their respective monoisotopic ion peak ([M]) after SLIM SUPER IMS with resolving powers of ∼400-600. Similar separations were obtained for other compounds (e.g., tetrapeptide ions). Greater separation was obtained using argon versus helium drift gas, as expected from the greater reduced mass contribution to ion mobility described by the Mason-Schamp relationship. To more directly explore the role of isotopic substitutions, we studied a mixture of specific isotopically substituted (15N, 13C, and 2H) protonated arginine isotopologues. While the separations in nitrogen were primarily due to their reduced mass differences, similar to the naturally occurring isotopologues, their separations in helium, where higher resolving powers could also be achieved, revealed distinct additional relative mobility shifts. These shifts appeared correlated, after correction for the reduced mass contribution, with changes in the ion center of mass due to the different locations of heavy atom substitutions. The origin of these apparent mass distribution-induced mobility shifts was then further explored using a mixture of Iodoacetyl Tandem Mass Tag (iodoTMT) isotopomers (i.e., each having the same exact mass, but with different isotopic substitution sites). Again, the observed mobility shifts appeared correlated with changes in the ion center of mass leading to multiple monoisotopic mobilities being observed for some isotopomers (up to a ∼0.04% difference in mobility). These mobility shifts thus appear to reflect details of the ion structure, derived from the changes due to ion rotation impacting collision frequency or momentum transfer, and highlight the potential for new approaches for ion structural characterization.


Assuntos
Deutério/química , Isótopos de Carbono/química , Espectrometria de Mobilidade Iônica , Íons/química , Íons/isolamento & purificação , Espectrometria de Massas , Isótopos de Nitrogênio/química
14.
Phys Chem Chem Phys ; 21(4): 1689-1699, 2019 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-30260357

RESUMO

This study examined the solution-phase exchange reactions of triphenylphosphine (PPh3) ligands on Au8L72+ (L = PPh3) gold clusters with three different tolyl ligands using electrospray ionization mass spectrometry to provide insight into how steric differences in the phosphines influence the extent of ligand exchange and the stability of the resulting mixed-phosphine clusters. The size distributions of tolyl-exchanged gold clusters were found to depend on the position of the methyl group in the tri(tolyl)phosphine ligands (-ortho, -meta, and -para). Due to different sterics, the tri(m-tolyl)phosphine (TMTP) and tri(p-tolyl)phosphine (TPTP) ligands exchanged efficiently onto the Au8L72+ (L = PPh3) clusters while the tri(o-tolyl)phosphine ligands did not exchange. In addition, while TPTP fully exchanged with all seven PPh3 on the Au8L72+ cluster, TMTP exchanged with only six PPh3 ligands. Employing collision-induced dissociation, the tolyl-exchanged mixed-ligand clusters were demonstrated to fragment through loss of neutral ligands and AuL2+. Comparison of the relative fragmentation yields of PPh3vs. TMTP and TPTP from the mixed-ligand clusters indicated that these tolyl ligands are more strongly bonded to the Au82+ gold core than PPh3. To provide molecular-level insight into the experimental results we also performed complementary electronic structure calculations using density functional theory at the B3LYP-D3/SDD level of theory on representative model systems. These computations revealed that steric interactions of the CH3 group on the tri(o-tolyl)phosphine ligand are responsible for the lack of ligand exchange in solution with PPh3. Our joint experimental and theoretical findings demonstrate the subtle interplay of steric and electronic factors that determine the size distribution, stability, and dissociation pathways of phosphine ligated gold clusters.

15.
Chem Soc Rev ; 47(3): 929-981, 2018 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-29188830

RESUMO

Organotransition metal complexes capable of forming metalloradicals have been an intriguing subject of study for the past fifty years. Of these, rhodium porphyrin complexes have proven particularly interesting due to their straightforward synthesis and unique reactivity; indeed, these complexes are responsible for some highly influential transformations of organic compounds, including rare C-H and C-C bond activations. The complexity and selectivity of rhodium porphyrins has been attractive for catalytic transformations, with specific interest in their usage for selective carbon monoxide reduction for fuel cell applications. This review will highlight historical and modern syntheses of rhodium porphyrins, as well as their respective reactions with small molecules and applications therein. The discussion will be limited to rhodium porphyrins consisting of four pyrrolic rings bridged with four methine units.

16.
Nature ; 487(7407): 390-3, 2012 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-22722848

RESUMO

The initiation of translation establishes the reading frame for protein synthesis and is a key point of regulation. Initiation involves factor-driven assembly at a start codon of a messenger RNA of an elongation-competent 70S ribosomal particle (in bacteria) from separated 30S and 50S subunits and initiator transfer RNA. Here we establish in Escherichia coli, using direct single-molecule tracking, the timing of initiator tRNA, initiation factor 2 (IF2; encoded by infB) and 50S subunit joining during initiation. Our results show multiple pathways to initiation, with orders of arrival of tRNA and IF2 dependent on factor concentration and composition. IF2 accelerates 50S subunit joining and stabilizes the assembled 70S complex. Transition to elongation is gated by the departure of IF2 after GTP hydrolysis, allowing efficient arrival of elongator tRNAs to the second codon presented in the aminoacyl-tRNA binding site (A site). These experiments highlight the power of single-molecule approaches to delineate mechanisms in complex multicomponent systems.


Assuntos
Escherichia coli/genética , Escherichia coli/metabolismo , Iniciação Traducional da Cadeia Peptídica/fisiologia , Fator de Iniciação 2 em Procariotos/metabolismo , RNA de Transferência/metabolismo , Subunidades Ribossômicas Maiores de Bactérias/metabolismo , Fatores de Tempo
17.
Spinal Cord ; 56(7): 643-655, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29515211

RESUMO

STUDY DESIGN: Narrative review. OBJECTIVES: To find and discuss what has been published about the use of telehealth, on people with spinal cord injury (teleSCI). SETTING: International. METHOD: Cochrane Library, Ovid Medline, EMBASE and CINAHL, from 1996 till June 2017 have been searched. Searches in  PsycINFO, from 1996 till September 2017, were included afterwards. Extracted data include studies in English language, containing information about spinal cord injury and disorders, and telehealth. Literature reviews, systematic reviews, and studies containing other types of neurological disorders, were excluded. Studies were grouped based on how and to whom telehealth was offered. RESULTS: Twenty nine studies were included in the review. They were categorized according to the way teleSCI was provided, and to what modality was used. Some studies utilized more than one modality. TeleSCI seems to be favorable concerning treatment and follow-up, as well as favorable socioeconomically and environmentally. The studies spanned across several aims and outcomes. There was also heterogeneity in number of participants, the differences in modalities, and in the level of evidence. Thus  it was challenging to compare studies  and make future recommendations. CONCLUSIONS: TeleSCI can be used for examination and guiding purposes. Further research is warranted to evaluate optimal utilization, methodology and efficacy. SPONSORSHIP: The first author has received funding from the Norwegian Extra Foundation.


Assuntos
Traumatismos da Medula Espinal/terapia , Telemedicina/métodos , Bases de Dados Factuais/estatística & dados numéricos , Humanos , Cooperação Internacional
18.
Cancer ; 123(14): 2642-2650, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-28222215

RESUMO

BACKGROUND: Early-stage and intermediate-stage nasopharyngeal cancer (NPC) generally carry a good prognosis, but for patients with recurrent, metastatic disease, options are limited. In the current study, the authors present a phase 1/2 study to evaluate the efficacy of Epstein-Barr virus (EBV)-stimulated cytotoxic T-lymphocyte (EBV-CTL) immunotherapy in this patient population. METHODS: Screening for patients with active, recurrent, metastatic EBV-associated NPC began in February 2007, and the study was closed to accrual in January 2012. After informed consent was obtained, patients had their blood drawn to initiate manufacturing of the EBV-CTL product. During product manufacturing, patients were placed on interim standard-of-care chemotherapy, and only after disease progression on the interim chemotherapy did patients receive investigational immunotherapy. Patients were restaged every 2 months until disease progression and then followed for survival. RESULTS: A total of 28 patients were enrolled, and 21 patients were treated. There was 1 complete response achieved, and at the time of last follow-up, the patient had been in remission for >8 years since treatment. The median progression-free survival was 2.2 months, and the median overall survival was 16.7 months. Two other patients, after failing EBV-CTL immunotherapy, unexpectedly demonstrated strong responses to the chemotherapy regimens they had previously failed. Patient EBV viral load and EBV-CTL specificity for tumor-associated viral antigens did not appear to correlate with clinical response. CONCLUSIONS: A durable response was observed with EBV-CTL immunotherapy, but the overall response rate for patients with recurrent, metastatic NPC was low. Further research is necessary to increase the efficacy of EBV-specific immunotherapy in patients with incurable NPC, and to characterize mechanisms for refacilitation to chemotherapy. Cancer 2017;123:2642-50. © 2017 American Cancer Society.


Assuntos
Neoplasias Ósseas/terapia , Carcinoma/terapia , Imunoterapia Adotiva/métodos , Neoplasias Hepáticas/terapia , Neoplasias Pulmonares/terapia , Neoplasias Nasofaríngeas/terapia , Recidiva Local de Neoplasia/terapia , Linfócitos T Citotóxicos/transplante , Adulto , Idoso , Neoplasias Ósseas/secundário , Carcinoma/patologia , Carcinoma/secundário , Carcinoma/virologia , Progressão da Doença , Intervalo Livre de Doença , ELISPOT , Estudos de Viabilidade , Feminino , Citometria de Fluxo , Herpesvirus Humano 4/imunologia , Humanos , Neoplasias Hepáticas/secundário , Neoplasias Pulmonares/secundário , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/patologia , Neoplasias Nasofaríngeas/secundário , Neoplasias Nasofaríngeas/virologia , Metástase Neoplásica , Recidiva Local de Neoplasia/virologia , Projetos Piloto , Linfócitos T Citotóxicos/imunologia , Adulto Jovem
20.
Anal Chem ; 89(5): 2838-2843, 2017 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-28192967

RESUMO

Resonance enhanced multiphoton ionization spectroscopy (REMPI) generates simultaneous vibronic spectroscopy and fragment free mass spectrometry to identify molecules within a complex matrix. We combined laser desorption with REMPI spectroscopy to study organic residues within pottery sherds from Maya vessels (600-900 CE) and Mississippian vessels (1100-1200 CE), successfully detecting three molecular markers, caffeine, theobromine, and theophylline, associated with the use of cacao. This analytical approach provides a high molecular specificity, based on both wavelength and mass identification. At the same time, the high detection limit allows for direct laser desorption from sherd scrapings, avoiding the need for extracting organic constituents from the sherd matrix.

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