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1.
Gastroenterology ; 161(3): 996-1010.e1, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34097885

RESUMO

BACKGROUNDS & AIMS: Fluoropyrimidine c (5-fluorouracil [5FU]) increasingly represents the chemotherapeutic backbone for neoadjuvant, adjuvant, and palliative treatment of pancreatic ductal adenocarcinoma (PDAC). Even in combination with other agents, 5FU efficacy remains transient and limited. One explanation for the inadequate response is insufficient and nonspecific delivery of 5FU to the tumor. METHODS: We designed, generated, and characterized 5FU-incorporated systematic evolution of ligands by exponential enrichment (SELEX)-selected epidermal growth factor receptor (EGFR)-targeted aptamers for tumor-specific delivery of 5FU to PDAC cells and tested their therapeutic efficacy in vitro and in vivo. RESULTS: 5FU-EGFR aptamers reduced proliferation in a concentration-dependent manner in mouse and human pancreatic cancer cell lines. Time-lapsed live imaging showed EGFR-specific uptake of aptamers via clathrin-dependent endocytosis. The 5FU-aptamer treatment was equally effective in 5FU-sensitive and 5FU-refractory PDAC cell lines. Biweekly treatment with 5FU-EGFR aptamers reduced tumor burden in a syngeneic orthotopic transplantation model of PDAC, in an autochthonously growing genetically engineered PDAC model (LSL-KrasG12D/+;LSL-Trp53flox/+;Ptf1a-Cre [KPC]), in an orthotopic cell line-derived xenograft model using human PDAC cells in athymic mice (CDX; Crl:NU-Foxn1nu), and in patient-derived organoids. Tumor growth was significantly attenuated during 5FU-EGFR aptamer treatment in the course of follow-up. CONCLUSIONS: Tumor-specific targeted delivery of 5FU using EGFR aptamers as the carrier achieved high target specificity; overcame 5FU resistance; and proved to be effective in a syngeneic orthotopic transplantation model, in KPC mice, in a CDX model, and in patient-derived organoids and, therefore, represents a promising backbone for pancreatic cancer chemotherapy in patients. Furthermore, our approach has the potential to target virtually any cancer entity sensitive to 5FU treatment by incorporating 5FU into cancer cell-targeting aptamers as the delivery platform.


Assuntos
Antimetabólitos Antineoplásicos/administração & dosagem , Aptâmeros de Nucleotídeos/administração & dosagem , Carcinoma Ductal Pancreático/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Receptores ErbB/metabolismo , Fluoruracila/administração & dosagem , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Antimetabólitos Antineoplásicos/metabolismo , Aptâmeros de Nucleotídeos/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Endocitose , Receptores ErbB/genética , Feminino , Fluoruracila/metabolismo , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Organoides , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Técnica de Seleção de Aptâmeros , Carga Tumoral/efeitos dos fármacos , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
2.
Indian Pacing Electrophysiol J ; 21(4): 209-218, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33866018

RESUMO

BACKGROUND: In patients with cardiac resynchronization therapy defibrillators (CRT-Ds), intracardiac impedance measured by dedicated CRT-D software may be used to monitor hemodynamic changes. We investigated the relationship of hemodynamic parameters assessed by intracardiac impedance and by echocardiography in a controlled clinical setting. METHODS: The study enrolled 68 patients (mean age, 66 ± 9 years; 74% males) at 12 investigational sites. The patients had an indication for CRT-D implantation, New York Heart Association class II/III symptoms, left ventricular ejection fraction 15%-35%, and a QRS duration ≥150 ms. Two months after a CRT-D implantation, hemodynamic changes were provoked by overdrive pacing. Intracardiac impedance was recorded at rest and at four pacing rates ranging from 10 to 40 beats/min above the resting rate. In parallel, echocardiography measurements were performed. We hypothesized that a mean intra-individual correlation coefficient (rmean) between stroke impedance (difference between end-systolic and end-diastolic intracardiac impedance) measured by CRT-D and the aortic velocity time integral (i.e., stroke volume) determined by echocardiography would be significantly larger than 0.65. RESULTS: The hypothesis was evaluated in 40 patients with complete data sets. The rmean was 0.797, with a lower confidence interval bound of 0.709. The study hypothesis was met (p = 0.007). A stepwise reduction of stroke impedance and stroke volume was observed with increasing heart rate. CONCLUSIONS: Intracardiac impedance measured by implanted CRT-Ds correlated well with the aortic velocity time integral (stroke volume) determined by echocardiography. The impedance measurements bear potential and are readily available technically, not requiring implantation of additional material beyond standard CRT-D system.

3.
Heart Vessels ; 34(7): 1196-1202, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30607538

RESUMO

According to current guidelines prophylactic implantable cardioverter-defibrillator (ICD) therapy is recommended in patients with significantly impaired left ventricular systolic function. However, the recently published DANISH trial did not find a significantly lower long-term rate of death from any cause compared with usual clinical care in patients with non-ischemic cardiomyopathy. We investigated whether registry data from a multi-center 'real-life' registry on patients with non-ischemic cardiomyopathy are similar to this trial. The German Device Registry (DEVICE) is a nationwide, prospective registry with one-year follow-up investigating 5451 patients receiving device implantations in 50 German centers. The present analysis of DEVICE focused on patients with non-ischemic cardiomyopathy and a left ventricular ejection fraction ≤35% who received a prophylactic ICD. Out of 779 patients with symptomatic heart failure and nonischemic cardiomyopathy, 33.1% received a single chamber ICD (VVI), while 11.0% were implanted with a dual-chamber ICD (DDD), and 55.8% received a defibrillator system for cardiac resynchronization therapy. Median follow-up was 16.1 months. 90.7% were alive at follow-up, 9.3% had died during this period. Overall mortality after one year was 5.4%. Overall mortality one year after implantation was significantly increased in patients 68 years and older(7.9%) as compared to younger patients (59-68 years: 2.5%; < 59 years: 3.8%; p < 0.015). Data from the present registry support the recently published results of the DANISH trial. In particular the influence of an increased age as proven in the DANISH trial might also play a role in the present collective. This limits the potential beneficial effect of ICD therapy in particular in the elderly population.


Assuntos
Terapia de Ressincronização Cardíaca/efeitos adversos , Cardiomiopatias/terapia , Morte Súbita Cardíaca/prevenção & controle , Desfibriladores Implantáveis/efeitos adversos , Idoso , Cardiomiopatias/mortalidade , Causas de Morte , Feminino , Alemanha/epidemiologia , Insuficiência Cardíaca , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Números Necessários para Tratar , Estudos Prospectivos , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Sistema de Registros , Taxa de Sobrevida
4.
J Electrocardiol ; 53: 100-108, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30739055

RESUMO

AIMS: Remote monitoring by implantable devices substantially improves management of heart failure (HF) patients by providing diagnostic day-to-day data. The use of thoracic impedance (TI) as a surrogate measure of fluid accumulation is still strongly debated. The multicenter HomeCARE-II study evaluated clinically apparent HF events in the context of remote device diagnostics, focusing on the controversial role of TI. METHODS AND RESULTS: We followed 497 patients (66.6 ±â€¯10.1 years, 77% male, QRS 139.8 ±â€¯36.0 ms, ejection fraction 26.8 ±â€¯7.0%) implanted with a CRT-D (67%) or an ICD (33%) for 21.4 ±â€¯8.1 months. An independent event committee confirmed 171 HF events of which 82 were used to develop a TI-based algorithm for the prediction of imminent cardiac decompensation. Highly inter-individual variations in patterns of TI trends were observed. The algorithm resulted in a sensitivity of 41.5% (50.0%) with 0.95 (1.34) false alerts per patient year, and a positive predictive value of 7.9% overall and 27.9% in the HF event group of patients. Averaged ratio statistics showed a significant pre-hospital decrease and a highly significant in-hospital increase in TI after intensified diuresis. Recurrent decompensations turned out to be preceded by a significantly stronger decrease of TI compared to first events with a higher chance for detection (63.6% sensitivity, p < 0.05). CONCLUSIONS: Overall performance in predicting imminent decompensation by monitoring TI alone is limited due to its high inter-patient variability. TI stand-alone applications should be redirected towards a target population with more advanced symptoms where post-hospital observation aimed to maintain the patient's discharge status might be the most valuable approach. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT00711360 (HomeCARE-II) and NCT01221649 (J-HomeCARE-II).


Assuntos
Cardiografia de Impedância/instrumentação , Insuficiência Cardíaca/fisiopatologia , Idoso , Algoritmos , Terapia de Ressincronização Cardíaca , Desfibriladores Implantáveis , Impedância Elétrica , Feminino , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/terapia , Humanos , Masculino , Estudos Prospectivos , Sensibilidade e Especificidade , Volume Sistólico
5.
Eur Heart J ; 39(13): 1065-1074, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29452351

RESUMO

Aims: The aim of this study was to investigate the effect of contact-to-balloon time on mortality in ST-segment elevation myocardial infarction (STEMI) patients with and without haemodynamic instability. Methods and results: Using data from the prospective, multicentre Feedback Intervention and Treatment Times in ST-Elevation Myocardial Infarction (FITT-STEMI) trial, we assessed the prognostic relevance of first medical contact-to-balloon time in n = 12 675 STEMI patients who used emergency medical service transportation and were treated with primary percutaneous coronary intervention (PCI). Patients were stratified by cardiogenic shock (CS) and out-of-hospital cardiac arrest (OHCA). For patients treated within 60 to 180 min from the first medical contact, we found a nearly linear relationship between contact-to-balloon times and mortality in all four STEMI groups. In CS patients with no OHCA, every 10-min treatment delay resulted in 3.31 additional deaths in 100 PCI-treated patients. This treatment delay-related increase in mortality was significantly higher as compared to the two groups of OHCA patients with shock (2.09) and without shock (1.34), as well as to haemodynamically stable patients (0.34, P < 0.0001). Conclusions: In patients with CS, the time elapsing from the first medical contact to primary PCI is a strong predictor of an adverse outcome. This patient group benefitted most from immediate PCI treatment, hence special efforts to shorten contact-to-balloon time should be applied in particular to these high-risk STEMI patients. Clinical Trial Registration: NCT00794001.


Assuntos
Angioplastia Coronária com Balão , Infarto do Miocárdio com Supradesnível do Segmento ST/mortalidade , Infarto do Miocárdio com Supradesnível do Segmento ST/cirurgia , Tempo para o Tratamento , Idoso , Idoso de 80 Anos ou mais , Serviços Médicos de Emergência , Feminino , Alemanha , Hemodinâmica , Mortalidade Hospitalar , Humanos , Masculino , Pessoa de Meia-Idade , Parada Cardíaca Extra-Hospitalar/mortalidade , Parada Cardíaca Extra-Hospitalar/fisiopatologia , Parada Cardíaca Extra-Hospitalar/cirurgia , Estudos Prospectivos , Infarto do Miocárdio com Supradesnível do Segmento ST/fisiopatologia , Choque Cardiogênico/etiologia , Choque Cardiogênico/mortalidade , Choque Cardiogênico/fisiopatologia , Choque Cardiogênico/cirurgia
6.
Nature ; 491(7424): 421-5, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-23151585

RESUMO

Long-distance quantum teleportation and quantum repeater technologies require entanglement between a single matter quantum bit (qubit) and a telecommunications (telecom)-wavelength photonic qubit. Electron spins in III-V semiconductor quantum dots are among the matter qubits that allow for the fastest spin manipulation and photon emission, but entanglement between a single quantum-dot spin qubit and a flying (propagating) photonic qubit has yet to be demonstrated. Moreover, many quantum dots emit single photons at visible to near-infrared wavelengths, where silica fibre losses are so high that long-distance quantum communication protocols become difficult to implement. Here we demonstrate entanglement between an InAs quantum-dot electron spin qubit and a photonic qubit, by frequency downconversion of a spontaneously emitted photon from a singly charged quantum dot to a wavelength of 1,560 nanometres. The use of sub-10-picosecond pulses at a wavelength of 2.2 micrometres in the frequency downconversion process provides the necessary quantum erasure to eliminate which-path information in the photon energy. Together with previously demonstrated indistinguishable single-photon emission at high repetition rates, the present technique advances the III-V semiconductor quantum-dot spin system as a promising platform for long-distance quantum communication.

7.
Opt Express ; 24(20): 23471-23480, 2016 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-27828410

RESUMO

Single photon sources are key components for various quantum information processing. For practical quantum applications, bright single photon sources with efficient fiber-optical interfaces are highly required. Here, bright fiber-coupled single photon sources based on InAs quantum dots are demonstrated through the k-vector matching between a microfiber mode and a normal mode of the linear photonic crystal cavity. One of the modes of the linear photonic crystal cavity whose k-vector is similar to that of the microfiber mode is employed. From independent transmission measurement, the coupling efficiency directly into the fiber of 58% is obtained. When the quantum dot and cavity system is non-resonantly pumped with 80 MHz pulse train, a raw count rate of 1.81 MHz is obtained with g(2)(0) = 0.46. Resonant pump is expected to improve the rather high g(2)(0) value. Time-resolved photoluminescence is also measured to confirm the three-fold Purcell enhancement. This system provides a promising route for efficient direct fiber collections of single photons for quantum information processing.

8.
Opt Express ; 24(8): 8539-46, 2016 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-27137291

RESUMO

The implementation and engineering of bright and coherent solid state quantum light sources is key for the realization of both on chip and remote quantum networks. Despite tremendous efforts for more than 15 years, the combination of these two key prerequisites in a single, potentially scalable device is a major challenge. Here, we report on the observation of bright single photon emission generated via pulsed, resonance fluorescence conditions from a single quantum dot (QD) deterministically centered in a micropillar cavity device via cryogenic optical lithography. The brightness of the QD fluorescence is greatly enhanced on resonance with the fundamental mode of the pillar, leading to an overall device efficiency of η = (74 ± 4) % for a single photon emission as pure as g(2)(0) = 0.0092 ± 0.0004. The combination of large Purcell enhancement and resonant pumping conditions allows us to observe a two-photon wave packet overlap up to ν = (88 ± 3) %.

9.
Opt Express ; 23(26): 32977-85, 2015 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-26831965

RESUMO

We report on the observation of bright emission of single photons under pulsed resonance fluorescence conditions from a single quantum dot (QD) in a micropillar cavity. The brightness of the QD fluorescence is greatly enhanced via the coupling to the fundamental mode of a micropillar, allowing us to determine a single photon extraction efficiency of (20.7 ± 0.8) % per linear polarization basis. This yields an overall extraction efficiency of (41.4 ± 1.5) % in our device. We observe the first Rabi-oscillation in a weakly coupled quantum dot-micropillar system under coherent pulsed optical excitation, which enables us to deterministically populate the excited QD state. In this configuration, we probe the single photon statistics of the device yielding g(2)(0) = 0.072 ± 0.011 at a QD-cavity detuning of 75 µeV.

11.
Opt Express ; 22(7): 8136-42, 2014 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-24718190

RESUMO

We report on a quasi-planar quantum-dot-based single-photon source that shows an unprecedented high extraction efficiency of 42% without complex photonic resonator geometries or post-growth nanofabrication. This very high efficiency originates from the coupling of the photons emitted by a quantum dot to a Gaussian shaped nanohill defect that naturally arises during epitaxial growth in a self-aligned manner. We investigate the morphology of these defects and characterize the photonic operation mechanism. Our results show that these naturally arising coupled quantum dot-defects provide a new avenue for efficient (up to 42% demonstrated) and pure (g(2)(0) value of 0.023) single-photon emission.

12.
J Crohns Colitis ; 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38869019

RESUMO

BACKGROUND AND AIMS: Ulcerative colitis (UC), a chronic inflammatory bowel disease, may manifest with symptoms of increased stool frequency (SF), rectal bleeding (RB), bowel urgency (BU), abdominal pain (AP), and fatigue. Mirikizumab, an anti-IL-23p19 antibody, demonstrated efficacy and safety in patients with moderately to severely active UC in the LUCENT Phase 3 trials. We evaluated mirikizumab's efficacy in achieving symptom control and time to symptom improvement during induction, maintenance of sustained symptom control, "comprehensive symptom control", defined according to a combination of individual patient-reported outcomes, and prognostic baseline indicators of early symptomatic remission at week 4. METHODS: The results of LUCENT-1/-2 have previously been reported. Treatment differences for symptomatic endpoints were compared over 52 weeks versus placebo (PBO) and comprehensive symptomatic endpoints at 12 and 52 weeks of continuous treatment. Subgroup analyses were conducted for prior biologic or tofacitinib treatment failure. Prognostic analyses were run using regression analysis. RESULTS: By Week (W)2, mirikizumab-treated patients achieved greater reductions in SF, RB, BU, and fatigue versus PBO. At W4, there was a higher rate of AP improvement. At W12, a greater proportion of mirikizumab-treated patients achieved symptomatic remission, RB remission, SF remission, and BU remission/clinically meaningful improvement. Mirikizumab-treated patients sustained symptom control versus placebo patients in maintenance until W52. This treatment effect was shown in patients regardless of prior biologic or tofacitinib failure. Additionally, mirikizumab achieved comprehensive symptom control versus PBO at W12 and W52. CONCLUSIONS: Mirikizumab demonstrated efficacy in achieving and sustaining symptom control and comprehensive symptom control over 52 weeks. [NCT03518086; NCT03524092].

13.
Radiother Oncol ; 198: 110386, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38880414

RESUMO

PET is increasingly used for target volume definition in the radiotherapy of glioblastoma, as endorsed by the 2023 ESTRO-EANO guidelines. In view of its growing adoption into clinical practice and upcoming PET-based multi-center trials, this paper aims to assist in overcoming common pitfalls of FET PET-based target delineation in glioblastoma.

14.
Clin Transl Radiat Oncol ; 45: 100706, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38116137

RESUMO

Background and purpose: The PRIDE trial (NOA-28; ARO-2022-12; NCT05871021) is scheduled to start recruitment in October 2023. Its primary objective is to enhance median overall survival (OS), compared to historical median OS rates, in patients with methylguanine methlyltransferase (MGMT) promotor unmethylated glioblastoma by incorporating isotoxic dose escalation to 75 Gy in 30 fractions. To achieve isotoxicity and counteract the elevated risk of radiation necrosis (RN) associated with dose-escalated regimens, the addition of protective concurrent bevacizumab (BEV) serves as an innovative approach. The current study aims to assess the dosimetric feasibility of the proposed concept. Materials and methods: A total of ten patients diagnosed with glioblastoma were included in this dosimetric analysis. Delineation of target volumes for the reference plans adhered to the ESTRO-EANO 2023 guideline. The experimental plans included an additional volume for the integrated boost. Additionally, the 60 Gy-volume was reduced by using a margin of 1.0 cm instead of 1.5 cm. To assess the risk of symptomatic RN, the Normal Tissue Complication Probability (NTCP) was calculated and compared between the reference and experimental plans. Results: Median NTCP of the reference plan (NTCPref) and of the experimental plan (NTCPex) were 0.24 (range 0.11-0.29) and 0.42 (range 0.18-0.54), respectively. NTCPex was a median of 1.77 (range 1.60-1.99) times as high as the NTXPref. In a logarithmic comparison, the risk of RN is enhanced by a factor of median 2.00 (range 1.66-2.35). The defined constraints for the organs at risk were feasible. Conclusion: When considering the potential protective effect of BEV, which we hypothesized might reduce the risk of RN by approximately two-fold, achieving isotoxicity with the proposed dose-escalated experimental plan for the PRIDE trial seems feasible.

15.
Clin Transl Radiat Oncol ; 47: 100790, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38765202

RESUMO

Background: The PRIDE trial (NOA-28; ARO-2024-01; AG-NRO-06; NCT05871021) is designed to determine whether a dose escalation with 75.0 Gy in 30 fractions can enhance the median overall survival (OS) in patients with methylguanine methyltransferase (MGMT) promotor unmethylated glioblastoma compared to historical median OS rates, while being isotoxic to historical cohorts through the addition of concurrent bevacizumab (BEV). To ensure protocol-compliant irradiation planning with all study centers, a dummy run was planned and the plan quality was evaluated. Methods: A suitable patient case was selected and the computed tomography (CT), magnetic resonance imaging (MRI) and O-(2-[18F]fluoroethyl)-L-tyrosine (FET) positron emission tomography (PET) contours were made available. Participants at the various intended study sites performed radiation planning according to the PRIDE clinical trial protocol. The treatment plans and dose grids were uploaded as Digital Imaging and Communications in Medicine (DICOM) files to a cloud-based platform. Plan quality and protocol adherence were analyzed using a standardized checklist, scorecards and indices such as Dice Score (DSC) and Hausdorff Distance (HD). Results: Median DSC was 0.89, 0.90, 0.88 for PTV60, PTV60ex (planning target volume receiving 60.0 Gy for the standard and the experimental plan, respectively) and PTV75 (PTV receiving 75.0 Gy in the experimental plan), respectively. Median HD values were 17.0 mm, 13.9 mm and 12.1 mm, respectively. These differences were also evident in the volumes: The PTV60 had a volume range of 219.1-391.3 cc (median: 261.9 cc) for the standard plans, while the PTV75 volumes for the experimental plans ranged from 71.5-142.7 cc (median: 92.3 cc). The structures with the largest deviations in Dice score were the pituitary gland (median 0.37, range 0.00-0.69) and the right lacrimal gland (median 0.59, range 0.42-0.78). Conclusions: The deviations revealed the necessity of systematic trainings with appropriate feedback before the start of clinical trials in radiation oncology and the constant monitoring of protocol compliance throw-out the study. Trial registration: NCT05871021.

16.
J Mol Cell Cardiol ; 64: 69-78, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23982034

RESUMO

Voltage-gated sodium channels are responsible for the rising phase of the action potential in cardiac muscle. Previously, both TTX-sensitive neuronal sodium channels (NaV1.1, NaV1.2, NaV1.3, NaV1.4 and NaV1.6) and the TTX-resistant cardiac sodium channel (NaV1.5) have been detected in cardiac myocytes, but relative levels of protein expression of the isoforms were not determined. Using a quantitative approach, we analyzed z-series of confocal microscopy images from individual mouse myocytes stained with either anti-NaV1.1, anti-NaV1.2, anti-NaV1.3, anti-NaV1.4, anti-NaV1.5, or anti-NaV1.6 antibodies and calculated the relative intensity of staining for these sodium channel isoforms. Our results indicate that the TTX-sensitive channels represented approximately 23% of the total channels, whereas the TTX-resistant NaV1.5 channel represented 77% of the total channel staining in mouse ventricular myocytes. These ratios are consistent with previous electrophysiological studies in mouse ventricular myocytes. NaV1.5 was located at the cell surface, with high density at the intercalated disc, but was absent from the transverse (t)-tubular system, suggesting that these channels support surface conduction and inter-myocyte transmission. Low-level cell surface staining of NaV1.4 and NaV1.6 channels suggest a minor role in surface excitation and conduction. Conversely, NaV1.1 and NaV1.3 channels are localized to the t-tubules and are likely to support t-tubular transmission of the action potential to the myocyte interior. This quantitative immunocytochemical approach for assessing sodium channel density and localization provides a more precise view of the relative importance and possible roles of these individual sodium channel protein isoforms in mouse ventricular myocytes and may be applicable to other species and cardiac tissue types.


Assuntos
Ventrículos do Coração/metabolismo , Miócitos Cardíacos/metabolismo , Canais de Sódio/metabolismo , Animais , Membrana Celular/metabolismo , Imuno-Histoquímica/métodos , Imuno-Histoquímica/normas , Espaço Intracelular/metabolismo , Masculino , Camundongos , Canal de Sódio Disparado por Voltagem NAV1.5/metabolismo , Isoformas de Proteínas , Transporte Proteico , Canais de Sódio/classificação
17.
J Mol Cell Cardiol ; 61: 133-141, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23702286

RESUMO

Voltage-gated sodium channels composed of a pore-forming α subunit and auxiliary ß subunits are responsible for the upstroke of the action potential in cardiac muscle. However, their localization and expression patterns in human myocardium have not yet been clearly defined. We used immunohistochemical methods to define the level of expression and the subcellular localization of sodium channel α and ß subunits in human atrial myocytes. Nav1.2 channels are located in highest density at intercalated disks where ß1 and ß3 subunits are also expressed. Nav1.4 and the predominant Nav1.5 channels are located in a striated pattern on the cell surface at the z-lines together with ß2 subunits. Nav1.1, Nav1.3, and Nav1.6 channels are located in scattered puncta on the cell surface in a pattern similar to ß3 and ß4 subunits. Nav1.5 comprised approximately 88% of the total sodium channel staining, as assessed by quantitative immunohistochemistry. Functional studies using whole cell patch-clamp recording and measurements of contractility in human atrial cells and tissue showed that TTX-sensitive (non-Nav1.5) α subunit isoforms account for up to 27% of total sodium current in human atrium and are required for maximal contractility. Overall, our results show that multiple sodium channel α and ß subunits are differentially localized in subcellular compartments in human atrial myocytes, suggesting that they play distinct roles in initiation and conduction of the action potential and in excitation-contraction coupling. TTX-sensitive sodium channel isoforms, even though expressed at low levels relative to TTX-sensitive Nav1.5, contribute substantially to total cardiac sodium current and are required for normal contractility. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes".


Assuntos
Átrios do Coração/metabolismo , Miocárdio/metabolismo , Canais de Sódio Disparados por Voltagem/metabolismo , Conexina 43/metabolismo , Átrios do Coração/patologia , Humanos , Técnicas In Vitro , Concentração Inibidora 50 , Contração Miocárdica , Miócitos Cardíacos/fisiologia , Especificidade de Órgãos , Subunidades Proteicas/metabolismo , Bloqueadores dos Canais de Sódio/farmacologia , Tetrodotoxina/farmacologia
18.
BMC Infect Dis ; 13: 111, 2013 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-23448529

RESUMO

BACKGROUND: Published models predicting nasal colonization with Methicillin-resistant Staphylococcus aureus among hospital admissions predominantly focus on separation of carriers from non-carriers and are frequently evaluated using measures of discrimination. In contrast, accurate estimation of carriage probability, which may inform decisions regarding treatment and infection control, is rarely assessed. Furthermore, no published models adjust for MRSA prevalence. METHODS: Using logistic regression, a scoring system (values from 0 to 200) predicting nasal carriage of MRSA was created using a derivation cohort of 3091 individuals admitted to a European tertiary referral center between July 2007 and March 2008. The expected positive predictive value of a rapid diagnostic test (GeneOhm, Becton & Dickinson Co.) was modeled using non-linear regression according to score. Models were validated on a second cohort from the same hospital consisting of 2043 patients admitted between August 2008 and January 2012. Our suggested correction score for prevalence was proportional to the log-transformed odds ratio between cohorts. Calibration before and after correction, i.e. accurate classification into arbitrary strata, was assessed with the Hosmer-Lemeshow-Test. RESULTS: Treating culture as reference, the rapid diagnostic test had positive predictive values of 64.8% and 54.0% in derivation and internal validation corhorts with prevalences of 2.3% and 1.7%, respectively. In addition to low prevalence, low positive predictive values were due to high proportion (> 66%) of mecA-negative Staphylococcus aureus among false positive results. Age, nursing home residence, admission through the medical emergency department, and ICD-10-GM admission diagnoses starting with "A" or "J" were associated with MRSA carriage and were thus included in the scoring system, which showed good calibration in predicting probability of carriage and the rapid diagnostic test's expected positive predictive value. Calibration for both probability of carriage and expected positive predictive value in the internal validation cohort was improved by applying the correction score. CONCLUSIONS: Given a set of patient parameters, the presented models accurately predict a) probability of nasal carriage of MRSA and b) a rapid diagnostic test's expected positive predictive value. While the former can inform decisions regarding empiric antibiotic treatment and infection control, the latter can influence choice of screening method.


Assuntos
Portador Sadio/microbiologia , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Modelos Biológicos , Cavidade Nasal/microbiologia , Infecções Estafilocócicas/microbiologia , Adolescente , Adulto , Idoso de 80 Anos ou mais , Calibragem , Portador Sadio/diagnóstico , Portador Sadio/epidemiologia , Estudos de Coortes , Técnicas de Apoio para a Decisão , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Dinâmica não Linear , Valor Preditivo dos Testes , Prevalência , Reprodutibilidade dos Testes , Fatores de Risco , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/prevenção & controle
19.
Cancers (Basel) ; 15(22)2023 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-38001664

RESUMO

The advancement of systemic targeted treatments has led to improvements in the management of metastatic disease, particularly in terms of survival outcomes. However, brain metastases remain less responsive to systemic therapies, underscoring the significance of local interventions for comprehensive disease control. Over the past years, the threshold for treating brain metastases through stereotactic radiosurgery has risen. Yet, as the number of treated metastases increases, treatment complexity and duration also escalate. This trend has made multi-isocenter radiosurgery treatments, such as those with the Gamma Knife, challenging to plan and lengthy for patients. In contrast, single-isocenter approaches employing linear accelerators offer an efficient and expeditious treatment option. This review delves into the literature, comparing different linear-accelerator-based techniques with each other and in relation to dedicated systems, focusing on dosimetric considerations and feasibility.

20.
Am Heart J ; 163(6): 938-45, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22709745

RESUMO

BACKGROUND: In current guidelines, intraaortic balloon pumping (IABP) is considered a class 1 indication in cardiogenic shock complicating acute myocardial infarction. However, evidence is mainly based on retrospective or prospective registries with a lack of randomized clinical trials. Therefore, IABP is currently only used in 20% to 40% of cardiogenic shock cases. The hypothesis of this trial is that IABP in addition to early revascularization by either percutaneous coronary intervention or coronary artery bypass grafting will improve clinical outcome of patients in cardiogenic shock. STUDY DESIGN: The IABP-SHOCK II study is a 600-patient, prospective, multicenter, randomized, open-label, controlled trial. The study is designed to compare the efficacy and safety of IABP versus optimal medical therapy on the background of early revascularization by either percutaneous coronary intervention or coronary artery bypass grafting. Patients will be randomized in a 1:1 fashion to 1 of the 2 treatments. The primary efficacy end point of IABP-SHOCK II is 30-day all-cause mortality. Secondary outcome measures, such as hemodynamic, laboratory, and clinical parameters, will serve as surrogate end points for prognosis. Furthermore, an intermediate and long-term follow-up at 6 and 12 months will be performed. Safety will be assessed, by the GUSTO bleeding definition, peripheral ischemic complications, sepsis, and stroke. CONCLUSIONS: The IABP-SHOCK II trial addresses important questions regarding the efficacy and safety of IABP in addition to early revascularization in patients with cardiogenic shock complicating myocardial infarction.


Assuntos
Balão Intra-Aórtico , Infarto do Miocárdio/complicações , Choque Cardiogênico/terapia , Ponte de Artéria Coronária , Humanos , Prognóstico , Estudos Prospectivos , Projetos de Pesquisa , Choque Cardiogênico/etiologia , Tiazóis
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