RESUMEN

The use of C-terminal peptide thioesters and hydrazides in synthetic protein chemistry has inspired the search for optimal solid-phase peptide synthesis (SPPS) strategies for their assembly. However, peptide thioesters are not directly accessible by conventional Fmoc-SPPS owing to the nucleophilicity of the secondary amine required for Fmoc removal. Here, we report the mild and effective activation of the pGlu linker and a new safety-catch linker that was used for the convenient synthesis of peptide thioesters and hydrazides via efficient amide-to-imide activation followed by nucleophilic displacement.

Asunto(s)

Amidas , Técnicas de Síntesis en Fase Sólida , Ésteres , Imidas , Péptidos

RESUMEN

OBJECTIVE: The present study proposes a model-based, statistical approach to characterizing episode patterns in paroxysmal atrial fibrillation (AF). Thanks to the rapid advancement of noninvasive monitoring technology, the proposed approach should become increasingly relevant in clinical practice. METHODS: History-dependent point process modeling is employed to characterize AF episode patterns, using a novel alternating, bivariate Hawkes self-exciting model. In addition, a modified version of a recently proposed statistical model to simulate AF progression throughout a lifetime is considered, involving non-Markovian rhythm switching and survival functions. For each model, the maximum likelihood estimator is derived and used to find the model parameters from observed data. RESULTS: Using three databases with a total of 59 long-term ECG recordings, the goodness-of-fit analysis demonstrates that the proposed alternating, bivariate Hawkes model fits SR-to-AF transitions in 40 recordings and AF-to-SR transitions in 51; the corresponding numbers for the AF model with non-Markovian rhythm switching are 40 and 11, respectively. Moreover, the results indicate that the model parameters related to AF episode clustering, i.e., aggregation of temporal AF episodes, provide information complementary to the well-known clinical parameter AF burden. CONCLUSION: Point process modeling provides a detailed characterization of the occurrence pattern of AF episodes that may improve the understanding of arrhythmia progression.

Asunto(s)

Fibrilación Atrial , Fibrilación Atrial/diagnóstico , Humanos

RESUMEN

OBJECTIVES: Lung cancer CT screening can reduce lung cancer mortality, but high false-positive rates may cause adverse psychosocial consequences. The aim was to analyse the psychosocial consequences of false-positive lung cancer CT screening using the lung cancer screening-specific questionnaire, Consequences of Screening in Lung Cancer (COS-LC). DESIGN AND SETTING: This study was a matched cohort study, nested in the randomised Danish Lung Cancer Screening Trial (DLCST). PARTICIPANTS: Our study included all 130 participants in the DLCST with positive CT results in screening rounds 2-5, who had completed the COS-LC questionnaire. Participants were split into a true-positive and a false-positive group and were then matched 1:2 with a control group (n=248) on sex, age (±3 years) and the time of screening for the positive CT groups or clinic visit for the control group. The true positives and false positives were also matched 1:2 with participants with negative CT screening results (n=252). PRIMARY OUTCOMES: Primary outcomes were psychosocial consequences measured at five time points. RESULTS: False positives experienced significantly more negative psychosocial consequences in seven outcomes at 1 week and in three outcomes at 1 month compared with the control group and the true-negative group (mean ∆ score >0 and p<0.001). True positives experienced significantly more negative psychosocial consequences in one outcome at 1 week (mean ∆ score 2.86 (95% CI 1.01 to 4.70), p=0.0024) and in five outcomes at 1 month (mean ∆ score >0 and p<0.004) compared with the true-negative group and the control group. No long-term psychosocial consequences were identified either in false positives or true positives. CONCLUSIONS: Receiving a false-positive result in lung cancer screening was associated with negative short-term psychosocial consequences. These findings contribute to the evidence on harms of screening and should be taken into account when considering implementation of lung cancer screening programmes. TRIAL REGISTRATION NUMBER: NCT00496977.

Asunto(s)

Detección Precoz del Cáncer/psicología , Neoplasias Pulmonares/psicología , Anciano , Ansiedad/epidemiología , Ansiedad/etiología , Estudios de Casos y Controles , Dinamarca , Detección Precoz del Cáncer/efectos adversos , Detección Precoz del Cáncer/métodos , Reacciones Falso Positivas , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Psicometría , Encuestas y Cuestionarios , Tomografía Computarizada por Rayos X/psicología

RESUMEN

OBJECTIVES: We investigated if psychosocial status, sociodemographics and smoking status affected non-attendance in the control group in the randomised Danish Lung Cancer Screening Trial (DLCST). DESIGN AND SETTING: This study was an observational study nested in the DLCST. Due to large non-attendance in the control group in the second screening round we made an additional effort to collect questionnaire data from non-attenders in this group in the third screening round. We used a condition-specific questionnaire to assess psychosocial status. We analysed the differences in psychosocial status in the third and preceding rounds between non-attenders and attenders in the control group in multivariable linear regression models adjusted for sociodemographics and smoking status reported at baseline. Differences in sociodemographics and smoking status were analysed with χ2 tests (categorical variables) and t-tests (continuous variables). PRIMARY OUTCOME MEASURE: Primary outcome was psychosocial status. PARTICIPANTS: All control persons participating in the third screening round in the DLCST were included. RESULTS: Non-attenders in the third round had significantly worse psychosocial status than attenders in the scales: 'behaviour' 0.77 (99% CI 0.18 to 1.36), 'self-blame' 0.59 (99% CI 0.14 to 1.04), 'focus on airway symptoms' 0.22 (99% CI 0.08 to 0.36), 'stigmatisation' 0.51 (99% CI 0.16 to 0.86), 'introvert' 0.56 (99% CI 0.23 to 0.89) and 'harms of smoking' 0.35 (99% CI 0.11 to 0.59). Moreover, non-attenders had worse scores than attendees in the preceding screening rounds. Non-attenders also reported worse sociodemographics at baseline. CONCLUSIONS: Non-attenders had a significantly worse psychosocial status and worse sociodemographics compared with attenders. The results of our study contribute with evidence of non-response and attrition driven by psychosocial status, which in turn may be influenced by the screening intervention itself. This can be used to adjust cancer screening trial results for bias due to differential non-attendance. TRIAL REGISTRATION NUMBER: Clinicaltrials.gov Protocol Registration System (NCT00496977).

Asunto(s)

Detección Precoz del Cáncer , Neoplasias Pulmonares , Pacientes no Presentados , Psicología , Fumar , Grupos Control , Dinamarca , Detección Precoz del Cáncer/efectos adversos , Detección Precoz del Cáncer/métodos , Detección Precoz del Cáncer/psicología , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/prevención & control , Masculino , Persona de Mediana Edad , Pacientes no Presentados/psicología , Pacientes no Presentados/estadística & datos numéricos , Variaciones Dependientes del Observador , Participación del Paciente/estadística & datos numéricos , Fumar/epidemiología , Fumar/psicología , Cese del Hábito de Fumar/métodos , Cese del Hábito de Fumar/psicología , Factores Socioeconómicos , Encuestas y Cuestionarios , Tomografía Computarizada por Rayos X/métodos

RESUMEN

INTRODUCTION: A study based on the Danish Randomised Controlled Lung Cancer Screening Trial (DLCST) calculated the healthcare costs of lung cancer screening by comparing costs in an intervention group with a control group. Participants in both groups, however, experienced significantly increased negative psychosocial consequences after randomisation. Substantial participation bias has also been documented: The DLCST participants reported fewer negative psychosocial aspects and experienced better living conditions compared with the random sample. OBJECTIVE: To comprehensively analyse the costs of lung cancer CT screening and to determine whether invitations to mass screening alter the utilisation of the healthcare system resulting in indirect costs. Healthcare utilisation and costs are analysed in the primary care sector (general practitioner psychologists, physiotherapists, other specialists, drugs) and the secondary care sector (emergency room contacts, outpatient visits, hospitalisation days, surgical procedures and non-surgical procedures). DESIGN: To account for bias in the original trial, the costs and utilisation of healthcare by participants in DLCST were compared with a new reference group, selected in the period from randomisation (2004-2006) until 2014. SETTING: Four Danish national registers. PARTICIPANTS: DLCST included 4104 current or former heavy smokers, randomly assigned to the CT group or the control group. The new reference group comprised a random sample of 535 current or former heavy smokers in the general Danish population who were never invited to participate in a cancer screening test. MAIN OUTCOME MEASURES: Total healthcare costs including costs and utilisation of healthcare in both the primary and the secondary care sector. RESULTS: Compared with the reference group, the participants in both the CT group (offered annual CT screening, lung function test and smoking counselling) and the control group (offered annual lung function test and smoking counselling) had significantly increased total healthcare costs, calculated at 60% and 48% respectively. The increase in costs was caused by increased use of healthcare in both the primary and the secondary sectors. CONCLUSION: CT screening leads to 60% increased total healthcare costs. Such increase would raise the expected annual healthcare cost per participant from EUR 2348 to EUR 3756. Cost analysis that only includes costs directly related to the CT scan and follow-up procedures most likely underestimates total costs. Our data show that the increased costs are not limited to the secondary sector. TRIAL REGISTRATION NUMBER: NCT00496977.

Asunto(s)

Detección Precoz del Cáncer/economía , Costos de la Atención en Salud/tendencias , Neoplasias Pulmonares/diagnóstico , Tamizaje Masivo/métodos , Sistema de Registros , Tomografía Computarizada por Rayos X/economía , Anciano , Dinamarca/epidemiología , Detección Precoz del Cáncer/métodos , Femenino , Humanos , Neoplasias Pulmonares/economía , Neoplasias Pulmonares/epidemiología , Masculino , Tamizaje Masivo/economía , Persona de Mediana Edad , Morbilidad/tendencias , Tasa de Supervivencia/tendencias

RESUMEN

The von Willebrand factor (VWF) and coagulation factor VIII (FVIII) are intricately involved in hemostasis. A tight, noncovalent complex between VWF and FVIII prolongs the half-life of FVIII in plasma, and failure to form this complex leads to rapid clearance of FVIII and bleeding diatheses such as hemophilia A and von Willebrand disease (VWD) type 2N. High-resolution insight into the complex between VWF and FVIII has so far been strikingly lacking. This is particularly the case for the flexible a3 region of FVIII, which is imperative for high-affinity binding. Here, a structural and biophysical characterization of the interaction between VWF and FVIII is presented with focus on two of the domains that have been proven pivotal for mediating the interaction, namely the a3 region of FVIII and the TIL'E' domains of VWF. Binding between the FVIII a3 region and VWF TIL'E' was here observed using NMR spectroscopy, where chemical shift changes were localized to two ß-sheet regions on the edge of TIL'E' upon FVIII a3 region binding. Isothermal titration calorimetry and NMR spectroscopy were used to characterize the interaction between FVIII and TIL'E' as well as mutants of TIL'E', which further highlights the importance of the ß-sheet region of TIL'E' for high-affinity binding. Overall, the results presented provide new insight into the role the FVIII a3 region plays for complex formation between VWF and FVIII and the ß-sheet region of TIL'E' is shown to be important for FVIII binding. Thus, the results pave the way for further high-resolution insights into this imperative complex.

Asunto(s)

Factor VIII/química , Factor VIII/metabolismo , Factor de von Willebrand/química , Factor de von Willebrand/metabolismo , Calorimetría , Espectroscopía de Resonancia Magnética , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Mutación/genética , Unión Proteica , Dominios Proteicos , Factor de von Willebrand/genética

RESUMEN

Methods for site-selective chemistry on proteins are in high demand for the synthesis of chemically modified biopharmaceuticals, as well as for applications in chemical biology, biosensors and more. Inadvertent N-terminal gluconoylation has been reported during expression of proteins with an N-terminal His tag. Here we report the development of this side-reaction into a general method for highly selective N-terminal acylation of proteins to introduce functional groups. We identify an optimized N-terminal sequence, GHHHn- for the reaction with gluconolactone and 4-methoxyphenyl esters as acylating agents, facilitating the introduction of functionalities in a highly selective and efficient manner. Azides, biotin or a fluorophore are introduced at the N-termini of four unrelated proteins by effective and selective acylation with the 4-methoxyphenyl esters. This Gly-Hisn tag adds the unique capability for highly selective N-terminal chemical acylation of expressed proteins. We anticipate that it can find wide application in chemical biology and for biopharmaceuticals.

Asunto(s)

Dipéptidos/metabolismo , Péptidos/metabolismo , Proteínas/metabolismo , Acilación , Secuencia de Aminoácidos , Azidas/química , Biotina/metabolismo , Ésteres/metabolismo , Colorantes Fluorescentes/química , Gluconatos/metabolismo , Lactonas/metabolismo , Péptidos/química , Polietilenglicoles/química , Procesamiento Proteico-Postraduccional

RESUMEN

PEGylation is the most widely used method to chemically modify protein biopharmaceuticals, but surprisingly limited public data is available on the biophysical effects of protein PEGylation. Here we report the first large-scale study, with site-specific mono-PEGylation of 15 different proteins and characterization of 61 entities in total using a common set of analytical methods. Predictions of molecular size were typically accurate in comparison with actual size determined by size-exclusion chromatography (SEC) or dynamic light scattering (DLS). In contrast, there was no universal trend regarding the effect of PEGylation on the thermal stability of a protein based on data generated by circular dichroism (CD), differential scanning calorimetry (DSC), or differential scanning fluorimetry (DSF). In addition, DSF was validated as a fast and inexpensive screening method for thermal unfolding studies of PEGylated proteins. Multivariate data analysis revealed clear trends in biophysical properties upon PEGylation for a subset of proteins, although no universal trends were found. Taken together, these findings are important in the consideration of biophysical methods and evaluation of second-generation biopharmaceutical drug candidates.

Asunto(s)

Polietilenglicoles/química , Proteínas/química , Biofisica/métodos , Rastreo Diferencial de Calorimetría/métodos , Cromatografía en Gel/métodos , Dicroismo Circular/métodos , Estabilidad Proteica , Temperatura

RESUMEN

RATIONALE: As of April 2015, participants in the Danish Lung Cancer Screening Trial had been followed for at least 5 years since their last screening. OBJECTIVES: Mortality, causes of death, and lung cancer findings are reported to explore the effect of computed tomography (CT) screening. METHODS: A total of 4,104 participants aged 50-70 years at the time of inclusion and with a minimum 20 pack-years of smoking were randomized to have five annual low-dose CT scans (study group) or no screening (control group). MEASUREMENTS AND MAIN RESULTS: Follow-up information regarding date and cause of death, lung cancer diagnosis, cancer stage, and histology was obtained from national registries. No differences between the two groups in lung cancer mortality (hazard ratio, 1.03; 95% confidence interval, 0.66-1.6; P = 0.888) or all-cause mortality (hazard ratio, 1.02; 95% confidence interval, 0.82-1.27; P = 0.867) were observed. More cancers were found in the screening group than in the no-screening group (100 vs. 53, respectively; P < 0.001), particularly adenocarcinomas (58 vs. 18, respectively; P < 0.001). More early-stage cancers (stages I and II, 54 vs. 10, respectively; P < 0.001) and stage IIIa cancers (15 vs. 3, respectively; P = 0.009) were found in the screening group than in the control group. Stage IV cancers were nonsignificantly more frequent in the control group than in the screening group (32 vs. 23, respectively; P = 0.278). For the highest-stage cancers (T4N3M1, 21 vs. 8, respectively; P = 0.025), this difference was statistically significant, indicating an absolute stage shift. Older participants, those with chronic obstructive pulmonary disease, and those with more than 35 pack-years of smoking had a significantly increased risk of death due to lung cancer, with nonsignificantly fewer deaths in the screening group. CONCLUSIONS: No statistically significant effects of CT screening on lung cancer mortality were found, but the results of post hoc high-risk subgroup analyses showed nonsignificant trends that seem to be in good agreement with the results of the National Lung Screening Trial. Clinical trial registered with www.clinicaltrials.gov (NCT00496977).

Asunto(s)

Adenocarcinoma/diagnóstico por imagen , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico por imagen , Carcinoma de Células Escamosas/diagnóstico por imagen , Neoplasias Pulmonares/diagnóstico por imagen , Pulmón/diagnóstico por imagen , Carcinoma Pulmonar de Células Pequeñas/diagnóstico por imagen , Adenocarcinoma/mortalidad , Adenocarcinoma/patología , Anciano , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Células Escamosas/mortalidad , Carcinoma de Células Escamosas/patología , Comorbilidad , Dinamarca/epidemiología , Detección Precoz del Cáncer , Femenino , Humanos , Pulmón/patología , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Enfermedad Pulmonar Obstructiva Crónica/epidemiología , Medición de Riesgo , Carcinoma Pulmonar de Células Pequeñas/mortalidad , Carcinoma Pulmonar de Células Pequeñas/patología , Fumar , Tomografía Computarizada por Rayos X

RESUMEN

Healthy individuals (n = 40) performed index finger tapping at freely chosen frequency during repeated bouts and before and after near-maximal muscle action consisting of 3 intense flexions of the index finger metacarpal phalangeal joint. One experiment showed, unexpectedly, that a bout of tapping increased the tapping frequency in the subsequent bout. Thus, a cumulating increase of 8.2 ± 5.4% (p < .001) occurred across 4 bouts, which were all separated by 10 min rest periods. Follow-up experiments revealed that tapping frequency was still increased in consecutive bouts when rest periods were extended to 20 min. Besides, near-maximal muscle activation, followed by 5 min rest, did not affect the tapping frequency. In conclusion, freely chosen tapping frequency was increased in repeated bouts of tapping, which were separated by 10-20 min rest periods. The observed phenomenon is suggested to be termed repeated bout rate enhancement.

Asunto(s)

Dedos/fisiología , Práctica Psicológica , Desempeño Psicomotor/fisiología , Adulto , Femenino , Articulaciones de los Dedos/fisiología , Falanges de los Dedos de la Mano/fisiología , Humanos , Masculino , Músculo Esquelético/fisiología , Reproducibilidad de los Resultados , Adulto Joven

RESUMEN

OBJECTIVES: To measure the psychosocial consequences in the Danish lung cancer screening trial (DLCST) and compare those between the computed tomography (CT) group and the control group. MATERIALS AND METHODS: This study was a single centre randomised controlled trial with five annual screening rounds. Healthy current or former heavy smokers aged 50-70 years (men and women) were randomised 1:1 to a CT group and a control group. Heavy smokers were defined by having smoked ≥20 pack years and former smokers by being abstinent ≤10 years. Both groups were invited annually to the screening clinic to complete the validated lung-cancer-specific questionnaire consequences of screening lung cancer (COS-LC). The CT group was also offered a low dose CT scan of the lungs. The COS-LC measures nine scales with psychosocial properties: Anxiety, Behaviour, Dejection, Negative impact on sleep, Self-blame, Focus on Airway Symptoms, Stigmatisation, Introvert, and Harm of Smoking. RESULTS: 4104 participants were randomised to the DLCST and the COS-LC completion rates for the CT group and the control group were 95.5% and 73.6%, respectively. There was a significant increase in negative psychosocial consequences from baseline through rounds 2-5 for both the CT group and the control group (mean increase >0, p<.0001 for 3 of 4 possible scales). During rounds 2-5 the control group experienced significantly more negative psychosocial consequences in seven of nine scales compared with the CT group (mean Δ score >0 and p<.033). CONCLUSIONS: Lung cancer CT-screening trials induced more negative psychosocial reactions in both the CT group and the control group compared with the baseline psychosocial profile. The CT group experienced less negative psychosocial consequences compared with the control group, which might be explained by reassurance among those with normal screening results. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00496977.

Asunto(s)

Detección Precoz del Cáncer , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/psicología , Adulto , Ansiedad , Dinamarca/epidemiología , Femenino , Humanos , Neoplasias Pulmonares/epidemiología , Masculino , Persona de Mediana Edad , Calidad de Vida , Factores de Riesgo , Encuestas y Cuestionarios , Tomografía Computarizada por Rayos X

RESUMEN

Neuromedin U (NMU) is a 25 amino acid peptide expressed and secreted in the brain and gastrointestinal tract. Data have shown that peripheral administration of human NMU decreases food intake and body weight and improves glucose tolerance in mice, suggesting that NMU receptors constitute a possible anti-diabetic and anti-obesity drug target. However, the clinical use of native NMU is hampered by a poor pharmacokinetic profile. In the current study, we report in vitro and in vivo data from a series of novel lipidated NMU analogs. In vitro plasma stability studies of native NMU were performed to investigate the proteolytic stability and cleavage sites using LC-MS. Native NMU was found to be rapidly cleaved at the C-terminus between Arg(24) and Asn(25) , followed by cleavage between Arg(16) and Gly(17) . Lipidated NMU analogs were generated using solid-phase peptide synthesis, and in vitro potency was investigated using a human embryonic kidney 293-based inositol phosphate accumulation assay. All lipidated analogs had preserved in vitro activity on both NMU receptors with potency improving as the lipidation site was moved away from the receptor-interacting C-terminal octapeptide segment. In vivo efficacy was assessed in lean mice as reduction in food intake after acute subcutaneous administration of 1, 0.3, 0.1, and 0.03 µmol/kg. These lipidated NMU analogs prolonged the anorectic effect of NMU in a dose-dependent manner. This was likely an effect of improved pharmacokinetic properties because of improved vitro plasma stability. Accordingly, the data demonstrate that lipidated NMU analogs may represent drug candidates for the treatment of obesity.

Asunto(s)

Ingestión de Alimentos/efectos de los fármacos , Neuropéptidos/síntesis química , Neuropéptidos/farmacología , Animales , Células Cultivadas , Relación Dosis-Respuesta a Droga , Estabilidad de Medicamentos , Células HEK293 , Humanos , Masculino , Ratones , Neuropéptidos/sangre , Neuropéptidos/química , Estabilidad Proteica

RESUMEN

Results from the American National Lung Screening Trial (NLST) show a significant reduction in lung cancer and all-cause mortality in a high risk population screened with annual low-dose CT. Handling of pulmonary nodules, false positive tests, overdiagnosis, psychosocial consequences and cost-efficiency etc. are all aspects that require careful consideration. This paper gives an overview of the current knowledge on these issues. Before a recommendation can be made, we need an overall evaluation of both the benefits and harms in CT screening for lung cancer.

Asunto(s)

Neoplasias Pulmonares/diagnóstico por imagen , Tamizaje Masivo , Análisis Costo-Beneficio , Errores Diagnósticos , Detección Precoz del Cáncer , Reacciones Falso Positivas , Humanos , Neoplasias Pulmonares/diagnóstico , Tamizaje Masivo/economía , Tamizaje Masivo/psicología , Tamizaje Masivo/normas , Dosis de Radiación , Factores de Riesgo , Fumar/psicología , Tomografía Computarizada por Rayos X/métodos

RESUMEN

Lung cancer is the cancer type that causes the largest number of deaths in Denmark. With advances in medical imaging and widespread use of computed tomography (CT), it is possible to detect even small abnormalities in lung tissue. This has led to a great interest in lung cancer screening with low-dose CT and launching of randomised screening trials worldwide. This paper gives an overview of the current lung cancer screening trials in Denmark and internationally and focuses on main lung cancer findings and mortality results.

Asunto(s)

Neoplasias Pulmonares , Tamizaje Masivo , Anciano , Dinamarca/epidemiología , Detección Precoz del Cáncer , Europa (Continente)/epidemiología , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/mortalidad , Masculino , Persona de Mediana Edad , Dosis de Radiación , Radiografía , Ensayos Clínicos Controlados Aleatorios como Asunto , Fumar , Tomografía Computarizada por Rayos X/métodos , Estados Unidos/epidemiología

RESUMEN

The presence of micron aggregates in protein formulations has recently attracted increased interest from regulatory authorities, industry, and academia because of the potential undesired side effects of their presence. In this study, we characterized the micron aggregate formation of hen egg-white lysozyme (Lyz) and its diPEGylated (5 kDa) analog as a result of typical handling stress conditions. Both proteins were subjected to mechanical stress in the absence and presence of silicone oil (SO), elevated temperatures, and freeze-thaw cycles. Flow imaging microscopy showed that PEGylated Lyz formed approximately half as many particles as Lyz, despite its lower apparent thermodynamic stability and more loose protein fold. Further characterization showed that the PEGylation led to a change from attractive to repulsive protein-protein interactions, which may partly explain the reduced particle formation. Surprisingly, the PEGylated Lyz adsorbed an order of magnitude faster onto SO, despite being much larger in size, as determined by small-angle X-ray scattering and dynamic light scattering measurements. Thus, PEGylation may significantly reduce, but not prevent, micron aggregate formation of a protein during typical handling stresses.

Asunto(s)

Polietilenglicoles/química , Proteínas/química , Rastreo Diferencial de Calorimetría , Dicroismo Circular , Microscopía , Espectrofotometría Ultravioleta

Asunto(s)

Neoplasias Pulmonares/diagnóstico por imagen , Tamizaje Masivo/efectos adversos , Tamizaje Masivo/métodos , Tomografía Computarizada por Rayos X/efectos adversos , Tomografía Computarizada por Rayos X/métodos , Humanos

RESUMEN

OBJECTIVES: Low dose computerised tomography (CT) screening for lung cancer can reduce lung-cancer-specific mortality. The objective of this study was to analyse healthcare costs and healthcare utilisation of participants in the Danish lung cancer CT-screening trial (DLCST). MATERIALS AND METHODS: This registry study was nested in a randomised controlled trial (DLCST). 4104 participants, current or former heavy smokers, aged 50-70 years were randomised to five annual low dose CT scans or usual care during 2004-2010. Total healthcare costs and healthcare utilisation data for both the primary and the secondary healthcare sector were retrieved from public registries from randomisation - September 2011 and compared between (1) the CT-screening group and the control group and, (2) the control group and each of the true-positive, false-positive and true-negative groups. RESULTS: The median annual costs per participant were significantly higher in the CT-screening group (Euros [EUR] 1342, interquartile range [IQR] 750-2980) compared with the control group (EUR 1190, IQR 590-2692) (p<0.0001). When the cost of the CT-screening programme was excluded, there was no longer a statistically significant difference between the CT-screening group (EUR 1155, IQR 567-2798) and the control group (p=0.52). Analyses according to the diagnostic groups showed that annual costs were 10.57 (95% CI 7.09-15.75) times higher for the true-positive and 1.67 (95% CI 1.20-2.32) times higher for the false-positive group compared with the control group. CONCLUSION: Low dose lung cancer CT screening increases healthcare costs compared with no screening; this difference was attributable to the costs of the CT-screening programme. Overall healthcare costs were higher for the true-positive and false-positive groups than for the control group, also when excluding the cost of the CT-screening programme. This increase was outweighed by the larger true-negative group showing no significant differences in costs compared with the control group.

Asunto(s)

Costos de la Atención en Salud/estadística & datos numéricos , Neoplasias Pulmonares/epidemiología , Sistema de Registros , Tomografía Computarizada por Rayos X , Anciano , Dinamarca , Detección Precoz del Cáncer , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico , Masculino , Tamizaje Masivo , Persona de Mediana Edad

RESUMEN

Hydrogenation of carbonaceous materials is important within carbon-based electronics, hydrogen storage, and the catalytic formation of molecular hydrogen in space. This study presents a systematic investigation at the density functional theory level of the hydrogenation of all small closed-shell polycyclic aromatic hydrocarbons comprising up to four carbon hexagons plus pentacene, hexacene, and heptacene. Binding energies span from 0.43 to 2.70 eV. Two-fold coordinated carbon atoms are preferred as binding sites with binding energies from 1.06 to 2.70 eV. Analyzing the binding sites yields three different motifs each with a clear structural and electronic fingerprint explaining the ordering of the binding sites.

Asunto(s)

Hidrógeno/química , Hidrocarburos Policíclicos Aromáticos/química , Estructura Molecular , Teoría Cuántica

RESUMEN

A site-selective dual-functionalization of peptides is presented, involving readily available maleimides as well as N-hydroxylamines. The modification proceeds through a three component 1,3-dipolar cycloaddition, forming a stable product. This was exemplified by the one-pot attachment of two molecular imaging moieties to a tumor binding cyclic peptide, and was extended to the conjugation of a DOTA chelator to a 12 kDa protein.

Asunto(s)

Péptidos Cíclicos/química , Sitios de Unión , Hidroxilamina/química , Maleimidas/química , Modelos Moleculares , Oxidación-Reducción , Conformación Proteica , Especificidad por Sustrato

RESUMEN

BACKGROUND: The effects of low-dose CT screening on disease stage shift, mortality and overdiagnosis are unclear. Lung cancer findings and mortality rates are reported at the end of screening in the Danish Lung Cancer Screening Trial. METHODS: 4104 men and women, healthy heavy smokers/former smokers were randomised to five annual low-dose CT screenings or no screening. Two experienced chest radiologists read all CT scans and registered the location, size and morphology of nodules. Nodules between 5 and 15 mm without benign characteristics were rescanned after 3 months. Growing nodules (>25% volume increase and/or volume doubling time<400 days) and nodules >15 mm were referred for diagnostic workup. In the control group, lung cancers were diagnosed and treated outside the study by the usual clinical practice. RESULTS: Participation rates were high in both groups (screening: 95.5%; control: 93.0%; p<0.001). Lung cancer detection rate was 0.83% at baseline and mean annual detection rate was 0.67% at incidence rounds (p=0.535). More lung cancers were diagnosed in the screening group (69 vs. 24, p<0.001), and more were low stage (48 vs 21 stage I-IIB non-small cell lung cancer (NSCLC) and limited stage small cell lung cancer (SCLC), p=0.002), whereas frequencies of high-stage lung cancer were the same (21 vs 16 stage IIIA-IV NSCLC and extensive stage SCLC, p=0.509). At the end of screening, 61 patients died in the screening group and 42 in the control group (p=0.059). 15 and 11 died of lung cancer, respectively (p=0.428). CONCLUSION: CT screening for lung cancer brings forward early disease, and at this point no stage shift or reduction in mortality was observed. More lung cancers were diagnosed in the screening group, indicating some degree of overdiagnosis and need for longer follow-up.

Asunto(s)

Neoplasias Pulmonares/diagnóstico por imagen , Tamizaje Masivo/métodos , Tomografía Computarizada por Rayos X/métodos , Anciano , Distribución de Chi-Cuadrado , Dinamarca/epidemiología , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Dosis de Radiación , Fumar/epidemiología , Encuestas y Cuestionarios