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1.
Nature ; 627(8005): 759-762, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38538936

RESUMO

The early evolution of a supernova (SN) can reveal information about the environment and the progenitor star. When a star explodes in vacuum, the first photons to escape from its surface appear as a brief, hours-long shock-breakout flare1,2, followed by a cooling phase of emission. However, for stars exploding within a distribution of dense, optically thick circumstellar material (CSM), the first photons escape from the material beyond the stellar edge and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating3. Early serendipitous observations2,4 that lacked ultraviolet (UV) data were unable to determine whether the early emission is heating or cooling and hence the nature of the early explosion event. Here we report UV spectra of the nearby SN 2023ixf in the galaxy Messier 101 (M101). Using the UV data as well as a comprehensive set of further multiwavelength observations, we temporally resolve the emergence of the explosion shock from a thick medium heated by the SN emission. We derive a reliable bolometric light curve that indicates that the shock breaks out from a dense layer with a radius substantially larger than typical supergiants.

2.
Ann Oncol ; 34(11): 1015-1024, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37657554

RESUMO

BACKGROUND: The optimal time to surgery (TTS) after neoadjuvant chemoradiotherapy (nCRT) for oesophageal cancer is unknown and has traditionally been 4-6 weeks in clinical practice. Observational studies have suggested better outcomes, especially in terms of histological response, after prolonged delay of up to 3 months after nCRT. The NeoRes II trial is the first randomised trial to compare standard to prolonged TTS after nCRT for oesophageal cancer. PATIENTS AND METHODS: Patients with resectable, locally advanced oesophageal cancer were randomly assigned to standard delay of surgery of 4-6 weeks or prolonged delay of 10-12 weeks after nCRT. The primary endpoint was complete histological response of the primary tumour in patients with adenocarcinoma (AC). Secondary endpoints included histological tumour response, resection margins, overall and progression-free survival in all patients and stratified by histologic type. RESULTS: Between February 2015 and March 2019, 249 patients from 10 participating centres in Sweden, Norway and Germany were randomised: 125 to standard and 124 to prolonged TTS. There was no significant difference in complete histological response between AC patients allocated to standard (21%) compared to prolonged (26%) TTS (P = 0.429). Tumour regression, resection margins and number of resected lymph nodes, total and metastatic, did not differ between the allocated interventions. The first quartile overall survival in patients allocated to standard TTS was 26.5 months compared to 14.2 months after prolonged TTS (P = 0.003) and the overall risk of death during follow-up was 35% higher after prolonged delay (hazard ratio 1.35, 95% confidence interval 0.94-1.95, P = 0.107). CONCLUSION: Prolonged TTS did not improve histological complete response or other pathological endpoints, while there was a strong trend towards worse survival, suggesting caution in routinely delaying surgery for >6 weeks after nCRT.


Assuntos
Adenocarcinoma , Neoplasias Esofágicas , Humanos , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/cirurgia , Quimiorradioterapia , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/cirurgia , Margens de Excisão , Terapia Neoadjuvante , Intervalo Livre de Progressão , Tempo para o Tratamento
3.
J Nutr Health Aging ; 27(6): 403-410, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37357322

RESUMO

OBJECTIVES: Aging is associated with changes in body composition. Excess adiposity among older adults has been linked with metabolic syndromes and aggravated age-associated decline in physical functioning. Few longitudinal studies have explored the association between dual-energy X-ray absorptiometry (DXA)-derived total as well as central adiposity measures and frailty. We examined the association of DXA-derived total and central adiposity with pre-frailty/frailty among Norwegian adults after 8 years of follow-up. DESIGN: Prospective observational study. SETTING: Community-dwelling adults from Tromsø, Norway. MEASUREMENTS: Adiposity was defined by fat mass index (FMI) and visceral adipose tissue (VAT) mass assessed using DXA measures. Frailty status was assessed by low grip strength, slow walking speed, exhaustion, unintentional weight loss and low physical activity level. Pre-frail and frail participants at baseline were excluded. Sex-stratified multivariable logistic regression models were used to investigate the association. RESULTS: Participants comprised 234 women (mean age 68 years) and 146 men (mean age 69 years) attending the population-based Tromsø Study in 2007-2008 (Tromsø6) and 2015-2016 (Tromsø7). At the end of follow-up, 25.6% of the women and 27.4% of the men were pre-frail/frail. Compared with women in the lowest tertiles, those in the highest tertile of baseline FMI (odds ratio [OR] 4.42, 95% confidence interval [CI] 1.88-10.35) and VAT mass (OR 2.47, 95% CI 1.10-5.50), respectively had higher odds for pre-frailty/frailty at follow-up. CONCLUSION: We found a higher likelihood of pre-frailty/frailty in later years among women with general and central adiposity in adulthood, highlighting the importance of preventing excess adiposity for healthy aging.


Assuntos
Adiposidade , Fragilidade , Masculino , Humanos , Feminino , Idoso , Fragilidade/epidemiologia , Absorciometria de Fóton , Obesidade , Envelhecimento , Obesidade Abdominal
4.
Chem Sci ; 14(24): 6621-6630, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37350826

RESUMO

Ultrafast transient absorption spectra were recorded for solutions of [MnIII(cyclam)(H2O)(OTf)][OTf]2 (cyclam = 1,4,8,11-tetraazacyclotetradecane and OTf = trifluoromethanesulfonate) in water to explore the possibility to restrict the equatorial expansion following photoexcitation of the dxy ← dz2 electronic transition, often resulting in a switch from axial to equatorial Jahn-Teller distortion in MnIII complexes. Strong oscillations were observed in the excited state absorption signal and were attributed to an excited state wavepacket. The structural rigidity of the cyclam ligand causes a complex reaction coordinate with frequencies of 333, 368, 454 and 517 cm-1, and a significantly shorter compressed-state lifetime compared to other MnIII complexes with less restricted equatorial ligands. Complementary density functional theory quantum chemistry calculations indicate a switch from an axially elongated to a compressed structure in the first excited quintet state Q1, which is accompanied by a modulation of the axial tilt angle. Computed harmonic frequencies for the axial stretching mode (∼379 cm-1) and the equatorial expansions (∼410 and 503 cm-1) of the Q1 state agree well with the observed coherences and indicate that the axial bond length contraction is significantly larger than the equatorial expansion, which implies a successful restriction of the wavepacket motion. The weak oscillation observed around 517 cm-1 is assigned to a see-saw motion of the axial tilt (predicted ∼610 cm-1). The results provide insights into the structural perturbations to the molecular evolution along excited state potential energy surfaces of MnIII octahedral complexes and can be used to guide the synthesis of optically controlled MnIII-based single-molecule magnets.

9.
Nat Chem ; 14(7): 722-723, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35778556

Assuntos
Ferro
10.
Dalton Trans ; 51(28): 10751-10757, 2022 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-35583816

RESUMO

Ultrafast transient absorption spectra were recorded for [Mn(terpy)X3], where X = Cl, F, and N3, to explore photoinduced switching from axial to equatorial Jahn-Teller (JT) distortion. Strong oscillations were observed in the transients, corresponding to a wavepacket on the excited-state potential energy surface with oscillation frequency around 115 cm-1 for all three complexes. Multireference quantum chemistry calculations indicate that the reaction coordinate is a pincer-like motion of the terpyridine ligand arising from bond length changes in the excited state due to the JT switch. We observed long dephasing times of the wavepacket, with times of 620 fs for [Mn(terpy)Cl3], 450 fs for [Mn(terpy)F3], and 370 fs for [Mn(terpy)(N3)3]. The dephasing time of these coherences decreases with an increasing number of vibrational modes at lower energy than the mode dominating the reaction coordinate, suggesting they act as an effective bath to dissipate the excess energy obtained from photoexcitation.

11.
Rev Sci Instrum ; 92(11): 113001, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34852523

RESUMO

We describe the development of a broadband magneto-optical spectrometer with femtosecond temporal resolution. The absorption spectrometer is based on a white-light supercontinuum (∼320 to 750 nm) using shot-to-shot temporal and spectral referencing at 1 kHz. Static and transient absorption spectra using circularly polarized light are collected in a magnetic field. The difference spectra with respect to the external field direction give the static and transient magneto-optical Faraday rotation (magnetic optical rotary dispersion) and ellipticity (magnetic circular dichroism) spectra. An achromatic quarter-wave plate is used, and the impact of the deviation from ideal retardance on the spectra is discussed. Results from solution-based and thin-film samples are used to demonstrate the performance and wide applicability of the instrument. The sensitivities for the static and time-resolved data were found to be 5 and 0.4 mdeg, respectively. The method presents a simple way to measure magneto-optical spectra using a transient absorption spectrometer and an electromagnet.

12.
Int J Med Inform ; 156: 104623, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34717179

RESUMO

BACKGROUND: The governance structures associated with health data are evolving in response to advances in digital technologies that enable new ways of capturing, using, and sharing different types of data. Increasingly, health data moves between different contexts such as from healthcare to research, or to commerce and marketing. Crossing these contextual boundaries has the potential to violate societal expectations about the appropriate use of health data and diminish public trust. Understanding citizens' views on the acceptability of and preferences for data use in different contexts is essential for developing information governance policies in these new contexts. METHODS: Focus group design presenting data sharing scenarios in England, Iceland, and Sweden. RESULTS: Seventy-one participants were recruited. Participants supported the need for data to help understand the observable world, improve medical research, the quality of public services, and to benefit society. However, participants consistently identified the lack of information, transparency and control as barriers to trusting organisations to use data in a way that they considered appropriate. There was considerable support for fair and transparent data sharing practices where all parties benefitted. CONCLUSION: Data governance policy should involve all stakeholders' perspectives on an ongoing basis, to inform and implement changes to health data sharing practices that accord with stakeholder views. The Findings showed that (1) data should be used for ethical purposes even when there was commercial interest; (2) data subjects and/or public institutions that provide and share data should also receive benefits from the sharing of data; (3) third parties use of data requires greater transparency and accountability than currently exists, (4) there should be greater information provided to empower data subjects.


Assuntos
Disseminação de Informação , Confiança , Inglaterra , Grupos Focais , Humanos , Islândia , Disseminação de Informação/ética , Suécia
13.
BJS Open ; 5(3)2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33960365

RESUMO

BACKGROUND: Oesophageal cancer management requires extensive in-hospital care. This cohort study aimed to quantify in-hospital care for patients with oesophageal cancer in relation to intended treatment, and to analyse factors associated with risk of spending a large proportion of survival time in hospital. METHODS: All patients with oesophageal cancer in three nationwide registers over a 10-year period were included. In-hospital care during the first year after diagnosis was evaluated, and the proportion of survival time spent in hospital, stratified by intended treatment (curative, palliative or best supportive care), was calculated. Associations between relevant factors and a greater proportion of survival time in hospital were analysed by multivariable logistic regression. RESULTS: In-hospital care was provided for a median of 39, 26, and 15 days in the first year after diagnosis of oesophageal cancer in curative, palliative, and best supportive care groups respectively. Patients receiving curatively intended treatment spent a median of 12 per cent of their survival time in hospital during the first year after diagnosis, whereas those receiving palliative or best supportive care spent 19 and 23 per cent respectively. Factors associated with more in-hospital care included older age, female sex, being unmarried, and chronic obstructive pulmonary disease. CONCLUSION: The burden of in-hospital care during the first year after diagnosis of oesophageal cancer was substantial. Important clinical and socioeconomic factors were identified that predisposed to a greater proportion of survival time spent in hospital.


Assuntos
Neoplasias Esofágicas , Idoso , Estudos de Coortes , Neoplasias Esofágicas/epidemiologia , Neoplasias Esofágicas/terapia , Feminino , Hospitais , Humanos , Modelos Logísticos
14.
Phys Chem Chem Phys ; 23(14): 8118-8131, 2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33875986

RESUMO

New magnetic materials and methods for controlling them are needed to improve data storage technologies. Recent progress has enabled optical detection and manipulation of spins in molecule-based magnets on the femtosecond timescale, which is promising for both increasing the read/write speed but also the data storage density. Experimental developments in femtosecond X-ray free-electron lasers (XFELs) and magneto-optics, in combination with theory advances, have opened up several new avenues to investigate molecule-based magnets. This review discusses the literature concerning ultrafast photoinduced dynamics in Prussian blue analogues (PBAs), which are molecule-based magnets. In PBAs spin-flips and lattice distortions can happen on the 100 fs timescale, which in some analogues lead to photoinduced changes in the long-range magnetic order. The literature and themes covered in this review are of relevance for ultrafast optical control of new multifunctional materials.

15.
BJS Open ; 5(2)2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33688944

RESUMO

BACKGROUND: There are marked geographical variations in the proportion of patients undergoing resection for gastric cancer. This study investigated the impact of resection rate on survival. METHODS: All patients with potentially curable gastric cancer between 2006 and 2017 were identified from the Swedish National Register of Oesophageal and Gastric Cancer. The annual resection rate was calculated for each county per year. Resection rates in all counties for all years were grouped into tertiles and classified as low, intermediate or high. Survival was analysed using the Cox proportional hazards model. RESULTS: A total of 3465 patients were diagnosed with potentially curable gastric cancer, and 1934 (55.8 per cent) were resected. Resection rates in the low (1261 patients), intermediate (1141) and high (1063) tertiles were 0-50.0, 50.1-62.5 and 62.6-100 per cent respectively. The multivariable Cox analysis revealed better survival for patients diagnosed in counties during years with an intermediate versus low resection rate (hazard ratio (HR) 0.81, 95 per cent c.i. 0.74 to 0.90; P < 0.001) and high versus low resection rate (HR 0.80, 0.73 to 0.88; P < 0.001). CONCLUSION: This national register study showed large regional variation in resection rates for gastric cancer. A higher resection rate appeared to be beneficial with regard to overall survival for the entire population.


Assuntos
Adenocarcinoma/mortalidade , Adenocarcinoma/cirurgia , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/cirurgia , Adenocarcinoma/patologia , Idade de Início , Feminino , Humanos , Masculino , Gradação de Tumores , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Sistema de Registros , Fatores de Risco , Sensibilidade e Especificidade , Neoplasias Gástricas/patologia , Taxa de Sobrevida , Suécia/epidemiologia
16.
Nat Commun ; 12(1): 56, 2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-33397922

RESUMO

RAC1 activity is critical for intestinal homeostasis, and is required for hyperproliferation driven by loss of the tumour suppressor gene Apc in the murine intestine. To avoid the impact of direct targeting upon homeostasis, we reasoned that indirect targeting of RAC1 via RAC-GEFs might be effective. Transcriptional profiling of Apc deficient intestinal tissue identified Vav3 and Tiam1 as key targets. Deletion of these indicated that while TIAM1 deficiency could suppress Apc-driven hyperproliferation, it had no impact upon tumourigenesis, while VAV3 deficiency had no effect. Intriguingly, deletion of either gene resulted in upregulation of Vav2, with subsequent targeting of all three (Vav2-/- Vav3-/- Tiam1-/-), profoundly suppressing hyperproliferation, tumourigenesis and RAC1 activity, without impacting normal homeostasis. Critically, the observed RAC-GEF dependency was negated by oncogenic KRAS mutation. Together, these data demonstrate that while targeting RAC-GEF molecules may have therapeutic impact at early stages, this benefit may be lost in late stage disease.


Assuntos
Carcinogênese/metabolismo , Carcinogênese/patologia , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Intestinos/patologia , Transdução de Sinais , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteína da Polipose Adenomatosa do Colo/metabolismo , Animais , Carcinogênese/genética , Homeostase , Intestinos/ultraestrutura , Camundongos Knockout , Mutação/genética , Especificidade de Órgãos , Fenótipo , Proteínas Proto-Oncogênicas c-vav/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteína 1 Indutora de Invasão e Metástase de Linfoma de Células T/metabolismo , Regulação para Cima , Via de Sinalização Wnt
17.
Brain Inj ; 35(1): 82-89, 2021 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-33297770

RESUMO

Introduction: Oculomotor (OM) functions may be affected by acquired brain injury (ABI). The ability to benefit from rehabilitation or to perform daily activities may be affected by OM dysfunctions and associated symptoms. The purpose of this study was to investigate the effects of vision therapy (VT) as part of neurorehabilitation after ABI.Materials and Methods: The study included two groups of outpatients (median 49.5-52.0 years, range 27-67) admitted to neurorehabilitation due to moderate to severe ABI. One group received VT while the other group served as controls to monitor the course of OM dysfunctions without VT.Results: The intervention group showed significant improvements in convergence (Z = 2.26, p = .02), vergence facility (Z = -2.16, p = .03) and vergence reserves (Z = -2.44, p < .01 and t = -4.47, DF = 15, p < .01) along with a significant reduction in vision-related symptoms (Z = 2.97, p < .01).Discussion: We conclude that OM issues were frequent and that targeted VT, as part of neurorehabilitation, can be an efficient treatment resulting in improved functions and reduced symptoms. Further study will be required to understand how improved functions link to performance and satisfaction with everyday activities.


Assuntos
Lesões Encefálicas , Reabilitação Neurológica , Lesões Encefálicas/complicações , Humanos , Pacientes Ambulatoriais , Satisfação Pessoal
18.
Toxicol In Vitro ; 71: 105068, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33301901

RESUMO

According to ISO 10993-1:2018, the skin sensitization potential of all medical devices must be evaluated, and for this endpoint ISO 10993-10:2010 recommends the use of in vivo assays. The goal of the present study was to determine if the in vitro SENS-IS assay could be a suitable alternative to the current in vivo assays. The SENS-IS assay uses the Episkin Large and SkinEthic RHE reconstructed human epidermis models to evaluate marker genes. In our study, the SENS-IS assay correctly identified 13 sensitizers spiked in a non-polar solvent. In a subsequent analysis six medical device silicone samples previously impregnated with sensitizers were extracted with polar and non-polar solvents. The SENS-IS assay correctly identified five of these extracts, while a sixth extract, which contained the weak sensitizer phenyl benzoate, was classified as negative. However, when this extract was concentrated, or a longer exposure time was used, the assay was able to detect phenyl benzoate. The SENS-IS assay was transferred to a naïve laboratory which correctly identified sensitizers in six blinded silicone samples, including the one containing phenyl benzoate. In light of these results, we conclude that the SENS-IS assay is able to correctly identify the presence of sensitizers in medical devices extracts.


Assuntos
Alternativas aos Testes com Animais , Bioensaio , Equipamentos e Provisões , Haptenos/toxicidade , Pele/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Humanos , Reprodutibilidade dos Testes , Pele/metabolismo
19.
Br J Surg ; 107(11): 1500-1509, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32484241

RESUMO

BACKGROUND: Only around one-quarter of patients with cancer of the oesophagus and the gastro-oesophageal junction (GOJ) undergo surgical resection. This population-based study investigated the rates of treatment with curative intent and resection, and their association with survival. METHODS: Patients diagnosed with oesophageal and GOJ cancer between 2006 and 2015 in Sweden were identified from the National Register for Oesophageal and Gastric Cancer (NREV). The NREV was cross-linked with several national registries to obtain information on additional exposures. The annual proportion of patients undergoing treatment with curative intent and surgical resection in each county was calculated, and the counties divided into groups with low, intermediate and high rates. Treatment with curative intent was defined as definitive chemoradiation therapy or surgery, with or without neoadjuvant oncological treatment. Overall survival was analysed using a multilevel model based on county of residence at the time of diagnosis. RESULTS: Some 5959 patients were included, of whom 1503 (25·2 per cent) underwent surgery. Median overall survival after diagnosis was 7·7, 8·8 and 11·1 months respectively in counties with low, intermediate and high rates of treatment with curative intent. Corresponding survival times for the surgical resection groups were 7·4, 9·3 and 11·0 months. In the multivariable analysis, a higher rate of treatment with curative intent (time ratio 1·17, 95 per cent c.i. 1·05 to 1·30; P < 0·001) and a higher resection rate (time ratio 1·24, 1·12 to 1·37; P < 0·001) were associated with improved survival after adjustment for relevant confounders. CONCLUSION: Patients diagnosed in counties with higher rates of treatment with curative intent and higher rates of surgery had better survival.


ANTECEDENTES: En los pacientes con cáncer en el esófago y de la unión gastroesofágica (gastroesophageal junction, GOJ), solamente en una cuarta parte se practica una resección quirúrgica. Este estudio de base poblacional analizó las tasas de tratamiento con intención curativa y de resección y su asociación con la supervivencia. MÉTODOS: A partir del Registro Nacional Sueco de Cáncer de Esófago y Estómago (National Register for Oesophageal and Gastric Cancer, NREV), se identificaron los pacientes diagnosticados de cáncer de esófago y de la GOJ entre 2006-2015. El NREV se cruzó con otros registros nacionales para obtener información adicional. Se calculó la proporción anual de pacientes tratados con intención curativa o mediante resección quirúrgica en cada una de las áreas territoriales de los condados y se categorizaron en baja, intermedia y alta. El tratamiento con intención curativa se definió como la quimiorradioterapia definitiva (definitive chemoradiation therapy, dCRT) o la cirugía, con o sin tratamiento oncológico neoadyuvante. Se analizó la supervivencia global con un modelo multinivel basado en el condado de residencia en el momento del diagnóstico. RESULTADOS: Se incluyeron 5.959 pacientes, de los que 1.503 (25,2%) fueron tratados quirúrgicamente. La mediana de supervivencia global después del tratamiento con intención curativa fue de 7,7, 8,8 y 11,1 meses para los condados de volumen bajo, intermedio y alto. Para el grupo de cirugía fue de 7,4, 9,3 y 11,0 meses, respectivamente. En el análisis multivariable, una mayor tasa de tratamiento con intención curativa y una mayor tasa de resección se asociaron con una mejor supervivencia (tiempo ganado 1,17; i.c. del 95% 1,05-1,30, P < 0,001 y tiempo ganado 1,24; i.c. del 95% 1,12-1,37, P < 0,001) después del ajuste para los factores principales de confusión. CONCLUSIÓN: Los pacientes diagnosticados en condados con tasas altas de tratamiento con intención curativa y de cirugía tuvieron una mejor supervivencia.


Assuntos
Adenocarcinoma/terapia , Carcinoma de Células Escamosas/terapia , Neoplasias Esofágicas/terapia , Junção Esofagogástrica , Disparidades em Assistência à Saúde/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Neoplasias Gástricas/terapia , Adenocarcinoma/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/mortalidade , Quimiorradioterapia/estatística & dados numéricos , Neoplasias Esofágicas/mortalidade , Esofagectomia/estatística & dados numéricos , Junção Esofagogástrica/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante/estatística & dados numéricos , Sistema de Registros , Estudos Retrospectivos , Neoplasias Gástricas/mortalidade , Análise de Sobrevida , Suécia/epidemiologia , Resultado do Tratamento
20.
Mol Cell Neurosci ; 105: 103498, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32389804

RESUMO

The BRICHOS domain is found in human precursor proteins associated with cancer, dementia (Bri2) and amyloid lung disease (proSP-C). Recombinant human (rh) proSP-C and Bri2 BRICHOS domains delay amyloid-ß peptide (Aß) fibril formation and reduce associated toxicity in vitro and their overexpression reduces Aß neurotoxicity in animal models of Alzheimer's disease. After intravenous administration in wild-type mice, rh Bri2, but not proSP-C, BRICHOS was detected in the brain parenchyma, suggesting that Bri2 BRICHOS selectively bypasses the blood-brain barrier (BBB). Here, our objective was to increase the brain delivery of rh proSP-C (trimer of 18 kDa subunits) and Bri2 BRICHOS (monomer to oligomer of 15 kDa subunits) using focused ultrasound combined with intravenous microbubbles (FUS + MB), which enables targeted and transient opening of the BBB. FUS + MB was targeted to one hemisphere of wild type mice and BBB opening in the hippocampal region was confirmed by magnetic resonance imaging. Two hours after FUS + MB brain histology showed no signs of tissue damage and immunohistochemistry showed abundant delivery to the brain parenchyma in 13 out of 16 cases given 10 mg/kg of proSP-C or Bri2 BRICHOS domains. The Bri2, but not proSP-C BRICHOS domain was detected also in the non-targeted hemisphere. ProSP-C and Bri2 BRICHOS domains were taken up by a subset of neurons in the hippocampus and cortex, and were detected to a minor extent in early endosomes. These results indicate that rh Bri2, but not proSP-C, BRICHOS, can be efficiently delivered into the mouse brain parenchyma and that both BRICHOS domains can be internalized by cell-specific mechanisms.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Hipocampo/metabolismo , Chaperonas Moleculares/metabolismo , Neurônios/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Feminino , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Microbolhas , Fragmentos de Peptídeos/metabolismo
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