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1.
Nano Lett ; 19(4): 2207-2214, 2019 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-30427688

RESUMO

Living cells interact with their immediate environment by exerting mechanical forces, which regulate important cell functions. Elucidation of such force patterns yields deep insights into the physics of life. Here we present a top-down nanostructured, ultraflexible nanowire array biosensor capable of probing cell-induced forces. Its universal building block, an inverted conical semiconductor nanowire, greatly enhances both the functionality and the sensitivity of the device. In contrast to existing cellular force sensing architectures, microscopy is performed on the nanowire heads while cells deflecting the nanowires are confined within the array. This separation between the optical path and the cells under investigation excludes optical distortions caused by cell-induced refraction, which can give rise to feigned displacements on the 100 nm scale. The undistorted nanowire displacements are converted into cellular forces via the nanowire spring constant. The resulting distortion-free cellular force transducer realizes a high-resolution and label-free biosenor based on optical microscopy. Its performance is demonstrated in a proof-of-principle experiment with living Dictyostelium discoideum cells migrating through the nanowire array. Cell-induced forces are probed with a resolution of 50 piconewton, while the most flexible nanowires promise to enter the 100 femtonewton realm.


Assuntos
Técnicas Biossensoriais , Rastreamento de Células/métodos , Nanoestruturas/química , Nanofios/química , Microscopia/métodos , Nanotecnologia/métodos , Óptica e Fotônica/tendências , Semicondutores , Transdutores
2.
HNO ; 67(7): 499-501, 2019 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-31119332

RESUMO

After the horrifying genocide in Rwanda in 1994, medical care of the small country almost broke down completely. During the following years, different medical fields had to be redeveloped. However, until 2009, there was no training program for otorhinolaryngology offered in Rwanda. Together with the University of Rwanda, we established a Master of Medicine Program that started in 2010. With the support of German otorhinolaryngologists, 10 ENT specialists have completed their training to date and 15 colleagues are currently still undergoing education in the program.


Assuntos
Otolaringologia , África , Otolaringologia/educação , Ruanda
3.
Internist (Berl) ; 59(11): 1163-1179, 2018 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-30280206

RESUMO

Endocrine disorders are the most common causes of secondary hypertension. Early diagnosis and specific treatment are crucial for improvement of the prognosis. This article provides an overview on which clinical constellations point to an increased risk of secondary causes of hypertension. These include spontaneous hypokalemia, young age at onset of hypertension, adrenal incidentaloma and therapy refractive arterial hypertension. The basic diagnostics include determination of the aldosterone to renin ratio, measurement of free plasma metanephrines and a 1 mg dexamethasone suppression test. Borderline results require repeated control testing and/or confirmatory testing under standardized test conditions. In cases of repeatedly conspicuous results referral to a specialized clinic should be considered for further clarification and confirmation of the diagnosis. Imaging diagnostics may constitute an adjunct to laboratory testing after the diagnosis has been confirmed. Therapeutic algorithms vary depending on the underlying endocrine disease.


Assuntos
Doenças do Sistema Endócrino/complicações , Hiperaldosteronismo/complicações , Hipertensão/etiologia , Algoritmos , Humanos , Hiperaldosteronismo/diagnóstico , Hipertensão/diagnóstico
4.
Ann Oncol ; 28(5): 1090-1097, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28453701

RESUMO

Background: Baseline clinical variables are prognostic for overall survival (OS) in patients with castration-resistant prostate cancer (CRPC). Their prognostic and predictive value with agents targeting bone metastases, such as radium-223, is not established. Patients and methods: The radium-223 ALSYMPCA trial enrolled patients with CRPC and symptomatic bone metastases. Prognostic potential of baseline variables was assessed using Cox models. Percentage changes in biomarker levels from baseline were evaluated during the trial period; changes from baseline to week 12 were evaluated for association with OS and surrogacy. Results: Eastern Cooperative Oncology Group performance status, total alkaline phosphatase (tALP), lactate dehydrogenase (LDH), and prostate-specific antigen (PSA) at baseline were associated with OS (P ≤ 0.0003) in the intent-to-treat population (radium-223, N = 614; placebo, N = 307). tALP declined from baseline within 4 weeks after beginning radium-223, by week 12 declining in 87% of radium-223 and 23% of placebo patients (P < 0.001). LDH declined in 51% and 34% (P = 0.003), whereas PSA declined in 27% and 14% (P = 0.160). Mean tALP change from baseline was 32.2% decrease with radium-223 and 37.2% increase with placebo. Radium-223 patients with tALP decline from baseline to week 12 (confirmed ≥3 weeks from week 12) had 55% lower risk of death (hazard ratio = 0.45; 95% CI 0.34-0.61) versus those with no confirmed tALP decline. Proportional treatment effect (PTE) values for tALP, LDH, and PSA changes from baseline at week 12 as OS surrogate markers were 0.34 (95% CI: 0-0.746), 0.07 (95% CI: 0-0.211), and 0 (95% CI: 0-0.082), respectively. Conclusions: Significant tALP declines (versus placebo) occurred as early as 4 weeks after beginning radium-223 therapy. tALP or LDH declines at 12 weeks correlated with longer OS, but did not meet statistical surrogacy requirements. Dynamic changes in tALP and LDH during radium-223 treatments may be useful to monitor, but do not serve as surrogates for survival.


Assuntos
Neoplasias de Próstata Resistentes à Castração/radioterapia , Compostos Radiofarmacêuticos/uso terapêutico , Rádio (Elemento)/uso terapêutico , Fosfatase Alcalina/metabolismo , Biomarcadores Tumorais/metabolismo , Humanos , Calicreínas/metabolismo , Estimativa de Kaplan-Meier , L-Lactato Desidrogenase/metabolismo , Masculino , Análise Multivariada , Prognóstico , Modelos de Riscos Proporcionais , Antígeno Prostático Específico/metabolismo , Neoplasias de Próstata Resistentes à Castração/enzimologia , Neoplasias de Próstata Resistentes à Castração/mortalidade , Resultado do Tratamento
5.
Ann Oncol ; 28(10): 2464-2471, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28961839

RESUMO

BACKGROUND: Six radium-223 injections at 4-week intervals is indicated for patients with castration-resistant prostate cancer and symptomatic bone metastases. However, patients usually develop disease progression after initial treatment. This prospective phase I/II study assessed re-treatment safety and efficacy of up to six additional radium-223 injections. PATIENTS AND METHODS: Patients had castration-resistant prostate cancer and bone metastases and six initial radium-223 injections with no on-treatment bone progression; all had subsequent radiologic or clinical progression. Concomitant agents were allowed at investigator discretion, excluding chemotherapy and initiation of new abiraterone or enzalutamide. The primary endpoint was safety; additional exploratory endpoints included time to radiographic bone progression, time to total alkaline phosphatase and prostate-specific antigen progression, radiographic progression-free survival, overall survival, time to first symptomatic skeletal event (SSE), SSE-free survival, and time to pain progression. RESULTS: Among 44 patients, 29 (66%) received all six re-treatment injections. Median time from end of initial radium-223 treatment was 6 months. Forty-one (93%) reported ≥1 treatment-emergent adverse event. No grade 4-5 hematologic treatment-emergent adverse events occurred. Only one (2%) patient had radiographic bone progression; eight (18%) had radiographic soft tissue tumor progression (three lymph node and five visceral metastases). Median times to total alkaline phosphatase and prostate-specific antigen progression were not reached and 2.2 months, respectively. Median radiographic progression-free survival was 9.9 months (12.8-month maximum follow-up). Five (11%) patients died and eight (18%) experienced first SSEs. Median overall survival, time to first SSE, and SSE-free survival were not reached. Five (14%) of 36 evaluable patients (baseline worst pain score ≤7) had pain progression. After 2 years of follow-up, 28 (64%) patients died, and the median overall survival was 24.4 months. CONCLUSIONS: Re-treatment with a second course of six radium-223 injections after disease progression is well tolerated, with minimal hematologic toxicity and low radiographic bone progression rates in this small study with limited follow-up. Favorable safety and early effects on disease progression indicate that radium-223 re-treatment is feasible and warrants further evaluation in larger prospective trials.


Assuntos
Neoplasias Ósseas/radioterapia , Neoplasias Ósseas/secundário , Neoplasias de Próstata Resistentes à Castração/radioterapia , Rádio (Elemento)/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Fosfatase Alcalina/metabolismo , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/metabolismo , Humanos , Calicreínas/metabolismo , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Antígeno Prostático Específico/metabolismo , Neoplasias de Próstata Resistentes à Castração/diagnóstico por imagem , Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Rádio (Elemento)/efeitos adversos , Reirradiação
6.
N Engl J Med ; 369(3): 213-23, 2013 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-23863050

RESUMO

BACKGROUND: Radium-223 dichloride (radium-223), an alpha emitter, selectively targets bone metastases with alpha particles. We assessed the efficacy and safety of radium-223 as compared with placebo, in addition to the best standard of care, in men with castration-resistant prostate cancer and bone metastases. METHODS: In our phase 3, randomized, double-blind, placebo-controlled study, we randomly assigned 921 patients who had received, were not eligible to receive, or declined docetaxel, in a 2:1 ratio, to receive six injections of radium-223 (at a dose of 50 kBq per kilogram of body weight intravenously) or matching placebo; one injection was administered every 4 weeks. In addition, all patients received the best standard of care. The primary end point was overall survival. The main secondary efficacy end points included time to the first symptomatic skeletal event and various biochemical end points. A prespecified interim analysis, conducted when 314 deaths had occurred, assessed the effect of radium-223 versus placebo on survival. An updated analysis, when 528 deaths had occurred, was performed before crossover from placebo to radium-223. RESULTS: At the interim analysis, which involved 809 patients, radium-223, as compared with placebo, significantly improved overall survival (median, 14.0 months vs. 11.2 months; hazard ratio, 0.70; 95% confidence interval [CI], 0.55 to 0.88; two-sided P=0.002). The updated analysis involving 921 patients confirmed the radium-223 survival benefit (median, 14.9 months vs. 11.3 months; hazard ratio, 0.70; 95% CI, 0.58 to 0.83; P<0.001). Assessments of all main secondary efficacy end points also showed a benefit of radium-233 as compared with placebo. Radium-223 was associated with low myelosuppression rates and fewer adverse events. CONCLUSIONS: In this study, which was terminated for efficacy at the prespecified interim analysis, radium-223 improved overall survival. (Funded by Algeta and Bayer HealthCare Pharmaceuticals; ALSYMPCA ClinicalTrials.gov number, NCT00699751.).


Assuntos
Neoplasias Ósseas/secundário , Neoplasias da Próstata/radioterapia , Rádio (Elemento)/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Neoplasias Ósseas/mortalidade , Neoplasias Ósseas/radioterapia , Método Duplo-Cego , Humanos , Isótopos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/patologia , Rádio (Elemento)/efeitos adversos
7.
Soft Matter ; 12(19): 4287-94, 2016 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-27139622

RESUMO

Control of living cells is vital for the survival of organisms. Each cell inside an organism is exposed to diverse external mechano-chemical cues, all coordinated in a spatio-temporal pattern triggering individual cell functions. This complex interplay between external chemical cues and mechanical 3D environments is translated into intracellular signaling loops. Here, we describe how external mechano-chemical cues control cell functions, especially cell migration, and influence intracellular information transport. In particular, this work focuses on the quantitative analysis of (1) intracellular vesicle transport to understand intracellular state changes in response to external cues, (2) cellular sensing of external chemotactic cues, and (3) the cells' ability to migrate in 3D structured environments, artificially fabricated to mimic the 3D environment of tissue in the human body.


Assuntos
Movimento Celular , Engenharia Tecidual , Quimiotaxia , Humanos , Transdução de Sinais , Alicerces Teciduais
8.
HNO ; 64(4): 213-6, 2016 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-26936381

RESUMO

BACKGROUND: All medical specialties are changing permanently, including otorhinolaryngology. Analyzing trends in social changes, medical progress, and political decisions will allow the effects of these on ENT medicine to be at least partially anticipated. TRENDS: Demographic changes and medical progress lead to an increasing demand for medical treatments. In addition, increasing numbers of female physicians are observed, as are many changes in the lifestyles of young physicians. Medical treatment will develop toward more individualized therapies in the future. ENT surgery will become a more ambulatory medical specialty. Driven by political decisions, digital medicine will become more important. Particular services once provided by physicians will be delegated to non-physician professionals. DISCUSSION: The lack of physicians and the progress in medicine require better networking between in- and outpatient services in the future. The potential of such collaborations is currently not completely realized. However, these developments will also increase the cost of health care. CONCLUSION: These trends will develop otorhinolaryngology into a conservative and surgical ambulatory care driven medical specialty. Embedded in decentralized networks and cooperations, and supported by IT technologies and specialized non-physician professionals, ENT physicians will work in hospitals as well as in practices on a permanent basis. Nevertheless, the question of funding these changes has yet to be clarified.


Assuntos
Otolaringologia/tendências , Otorrinolaringopatias/diagnóstico , Otorrinolaringopatias/terapia , Equipe de Assistência ao Paciente/tendências , Política , Mudança Social , Atenção à Saúde/tendências , Previsões , Alemanha , Política de Saúde/tendências
9.
Soft Matter ; 11(38): 7606-16, 2015 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-26291429

RESUMO

We have used low-field (1)H nuclear-magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) to investigate the aggregation dynamics of magnetic particles in ionic ferrofluids (IFFs) in the presence of magnetic field gradients. At the beginning of the experiments, the measured NMR spectra were broad and asymmetric, exhibiting two features attributed to different dynamical environments of water protons, depending on the local strength of the field gradients. Hence, the spatial redistribution of the magnetic particles in the ferrofluid caused by the presence of an external magnetic field in a time scale of minutes can be monitored in real time, following the changes in the features of the NMR spectra during a period of about an hour. As previously reported [Heinrich et al., Phys. Rev. Lett., 2011, 106, 208301], in the homogeneous magnetic field of a NMR spectrometer, the aggregation of the particles of the IFF proceeds in two stages. The first stage corresponds to the gradual aggregation of monomers prior to and during the formation of chain-like structures. The second stage proceeds after the chains have reached a critical average length, favoring lateral association of the strings into hexagonal zipped-chain superstructures or bundles. In this work, we focus on the influence of a strongly inhomogeneous magnetic field on the aforementioned aggregation dynamics. The main observation is that, as the sample is immersed in a certain magnetic field gradient and kept there for a time τinh, magnetophoresis rapidly converts the ferrofluid into an aggregation state which finds its correspondence to a state on the evolution curve of the pristine sample in a homogeneous field. From the degree of aggregation reached at the time τinh, the IFF sample just evolves thereafter in the homogeneous field of the NMR spectrometer in exactly the same way as the pristine sample. The final equilibrium state always consists of a colloidal suspension of zipped-chain bundles with the chain axes aligned along the magnetic field direction.


Assuntos
Coloides/química , Nanopartículas de Magnetita/química , Dimerização , Íons/química , Campos Magnéticos , Espectroscopia de Ressonância Magnética , Simulação de Dinâmica Molecular
10.
Scand J Med Sci Sports ; 24(3): e180-7, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24118532

RESUMO

Recent data highlight that competitive skiers face a high risk of injuries especially during off-balance jump landing maneuvers in downhill skiing. The purpose of the present study was to develop a musculo-skeletal modeling and simulation approach to investigate the cause-and-effect relationship between a perturbed landing position, i.e., joint angles and trunk orientation, and the peak force in the anterior cruciate ligament (ACL) during jump landing. A two-dimensional musculo-skeletal model was developed and a baseline simulation was obtained reproducing measurement data of a reference landing movement. Based on the baseline simulation, a series of perturbed landing simulations (n = 1000) was generated. Multiple linear regression was performed to determine a relationship between peak ACL force and the perturbed landing posture. Increased backward lean, hip flexion, knee extension, and ankle dorsiflexion as well as an asymmetric position were related to higher peak ACL forces during jump landing. The orientation of the trunk of the skier was identified as the most important predictor accounting for 60% of the variance of the peak ACL force in the simulations. Teaching of tactical decisions and the inclusion of exercise regimens in ACL injury prevention programs to improve trunk control during landing motions in downhill skiing was concluded.


Assuntos
Ligamento Cruzado Anterior/fisiopatologia , Movimento/fisiologia , Fenômenos Fisiológicos Musculoesqueléticos , Esqui/fisiologia , Articulação do Tornozelo/fisiologia , Lesões do Ligamento Cruzado Anterior , Fenômenos Biomecânicos , Simulação por Computador , Articulação do Quadril/fisiologia , Humanos , Articulação do Joelho/fisiologia , Modelos Biológicos , Postura/fisiologia , Tronco/fisiologia
11.
Scand J Med Sci Sports ; 24(3): 577-85, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23289971

RESUMO

A ski-snow interaction model is presented. The force between ski and snow is decomposed into a penetration force normal to the snow surface, a shear force parallel to it, and friction. The purpose of this study was to investigate the benefits of a hypoplastic vs an elastic contact for penetration in the simulation of skiing turns. To reduce the number of influencing factors, a sledge equipped with skis was considered. A forward dynamic simulation model for the sledge was implemented. For the evaluation of both contact models, the deviation between simulated trajectories and experimental track data was computed for turns of 67 and 42 m. Maximum deviations for these turns were 0.44 and 0.14 m for the hypoplastic contact, and 0.6 and 7.5 m for the elastic contact, respectively. In the hypoplastic contact, the penetration depth of the ski's afterbody maintained nearly the same value as the part under maximum load, whereas it decreased in the elastic contact. Because the shear force is proportional to the penetration depth, the hypoplastic contact resulted in a higher shearing resistance. By replacing the sledge with a skier model, one may investigate more complex skier actions, skiing performance, or accident-prone skiing maneuvers.


Assuntos
Elasticidade , Modelos Teóricos , Movimento (Física) , Esqui , Fricção , Resistência ao Cisalhamento , Neve , Equipamentos Esportivos
12.
Sci Rep ; 14(1): 3115, 2024 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-38326644

RESUMO

Knee ligament sprains are common during change-of-direction (COD) maneuvers in multidirectional team sports. This study aimed to compare the effects of an 8-week injury prevention exercise program containing COD-specific exercises and a similar program containing linear sprint exercises on injury- and performance-related variables during a 135° COD task. We hypothesized that the COD-specific training would lead to (H1) stronger reductions in biomechanical variables associated with anterior cruciate ligament (ACL) injury risk during COD, i.e. knee abduction moment and angle, hip internal rotation angle and lateral trunk lean, and (H2) more effective improvements in COD performance according to the COD completion time, executed angle, ground contact time, and approach speed. Twenty-two sports science students (40% female) completed biomechanical assessments of COD movement strategies before and after participating in two supervised 25-min training sessions per week over 8 weeks. We observed significant 'training x group' interaction effects in support of H1: the COD-specific training but not the linear sprint training led to reduced peak knee abduction moments (interaction, p = 0.027), initial knee abduction (interaction, p < 0.001), and initial lateral trunk lean angles (interaction, p < 0.001) compared to baseline. Although the COD-specific training resulted in sharper executed angles (interaction, p < 0.001), the sprint-specific training group showed reduced COD completion (interaction, p = 0.037) and ground contact times (interaction, p < 0.001). In conclusion, a combination of generic and COD-specific injury prevention training resulted in COD technique adaptations that can help to avoid ACL injury-prone COD movements but may negatively affect COD speed.


Assuntos
Lesões do Ligamento Cruzado Anterior , Traumatismos do Joelho , Entorses e Distensões , Humanos , Feminino , Masculino , Lesões do Ligamento Cruzado Anterior/prevenção & controle , Articulação do Joelho , Ligamento Cruzado Anterior , Traumatismos do Joelho/prevenção & controle , Terapia por Exercício/métodos , Fenômenos Biomecânicos , Movimento
13.
HNO ; 60(7): 626-36, 2012 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-22763767

RESUMO

OBJECTIVE: Speech audiometry studies do not deliver structured testimony of patients as to the actual benefit of hearing aids based on individual daily life experiences. This deficiency can be resolved by applying structured inventory questionnaires. The APHAB (German version) is an evaluated inventory questionnaire consisting of six questions put to patients with hearing deficiencies with and without hearing aids in four different hearing situations. MATERIALS AND METHODS: We collected the APHAB data of 560 patients before and after fitting hearing aids. We also gathered personal data as to age, prior experience with hearing aids, duration of daily use of the hearing aid and degree of hearing loss. RESULTS: The average age of the patients was a little under 70 years, 84% had just received their first hearing aid, and 83% exhibited moderate or severe hearing loss. The APHAB results were classified in percentile and contingency tables. The latter allow one to determine conditional probabilities of the potential success of fitting a hearing aid to a new patient for each APHAB scale. CONCLUSIONS: The APHAB can be applied regularly to measure the benefit of fitting a hearing aid to a patient in particular in problematic hearing situations. By registering the personal view of the patients, it expands the scope of the standard methods (e.g., speech audiometry) so that the quality of diagnostics and therapy can be improved. It qualitatively records the success of hearing aid fitting, predicts potential problem areas and thereby may reduce the number of unused hearing aids.


Assuntos
Auxiliares de Audição/estatística & dados numéricos , Perda Auditiva/diagnóstico , Perda Auditiva/reabilitação , Avaliação de Resultados em Cuidados de Saúde/métodos , Índice de Gravidade de Doença , Inquéritos e Questionários , Idoso , Feminino , Alemanha/epidemiologia , Perda Auditiva/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Prognóstico , Ajuste de Prótese/métodos , Ajuste de Prótese/estatística & dados numéricos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Resultado do Tratamento
14.
HNO ; 60(3): 240-8, 2012 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-22037968

RESUMO

OBJECTIVE: To date, no secondary prevention program is in place for patients carrying an increased risk for developing head and neck cancer (HNSCC). In terms of successful, long-term curative therapy and increased quality of life, it would be useful to detect such diseases at an early stage. PATIENTS AND METHODS: A total of 370 patients with at least one risk factor such as "smoking", "alcohol", or "reflux disease" and without any symptoms were examined during a 1-year period using standard HNO methods (e. g. endoscopy) for suspicious alterations of the mucosa of the upper aerodigestive tract. RESULTS: In 13 (3.5%) of all 370 cases a biopsy was taken for further diagnosis. Squamous cell carcinoma was found in eight cases, while one further patient was suffering from non-Hodgkin lymphoma. CONCLUSIONS: It is simple and safe to examine patients at risk of developing HNSCC by standard HNO methods. The rate of detected carcinomas is much higher than in former investigations, likely because our survey focused only on patients with specific risk factors.


Assuntos
Neoplasias de Cabeça e Pescoço/epidemiologia , Neoplasias de Cabeça e Pescoço/patologia , Programas de Rastreamento/estatística & dados numéricos , Mucosa Bucal/patologia , Otolaringologia/estatística & dados numéricos , Prática Privada/estatística & dados numéricos , Diagnóstico Precoce , Feminino , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Medição de Risco , Fatores de Risco
15.
Phys Rev Lett ; 106(20): 208301, 2011 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-21668267

RESUMO

Combining nuclear magnetic resonance and molecular dynamics simulations, we unravel the long-time dynamics of a paradigmatic colloid with strong dipole-dipole interactions. In a homogeneous magnetic field, ionic ferrofluids exhibit a stepwise association process from ensembles of monomers over stringlike chains to bundles of hexagonal zipped-chain patches. We demonstrate that attractive van der Waals interactions due to charge-density fluctuations in the magnetic particles play the key role for the dynamical stabilization of the hexagonal superstructures against thermal dissociation. Our results give insight into the dynamics of self-organization in systems dominated by dipolar interactions.

16.
Respiration ; 81(4): 345-50, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21266795

RESUMO

Bronchial carcinoid tumors account for 1-2% of all primary lung tumors and are separated into 2 subgroups: typical and atypical carcinoids. Atypical carcinoids as intermediate-grade malignancies can metastasize more frequently, thus exhibiting poorer prognosis than the low-grade typical carcinoid tumors. Surgical resection remains the mainstay of treatment for pulmonary carcinoids. Bronchoscopic treatment using ablation techniques is an effective alternative to surgery in selected patients with typical carcinoid tumors. However, evidence is lacking regarding the effect of bronchoscopic resection of atypical carcinoid tumor and its recurrences. We report the case of a 73-year-old male with frequent endobronchial recurrences of a previously surgically resected atypical carcinoid tumor successfully treated using Nd:YAG laser photoresection. Furthermore, the therapeutic and local staging aspects of the disease are discussed emphasizing the efficacy of bronchoscopic resection strategies and the value of novel bronchoscopic imaging techniques in detailed inspection of the structures of the bronchial wall.


Assuntos
Broncoscopia , Tumor Carcinoide/cirurgia , Neoplasias Pulmonares/cirurgia , Recidiva Local de Neoplasia/cirurgia , Idoso , Neoplasias Brônquicas/cirurgia , Humanos , Masculino , Cuidados Paliativos
17.
Ophthalmologe ; 118(2): 169-174, 2021 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-32248296

RESUMO

The treatment options for patients with metastatic melanoma (MM) have been dramatically expanded in recent years with the approval of new drugs. The MEK (mitogen-acitvated protein kinase kinase) and BRAF (serine/threonine-protein kinase B-Raf coding gene) inhibitor combination therapy is currently part of the standard of care for stage IIIC/IV of BRAF mutant melanoma. The MEK inhibitor-associated retinopathy (MEKAR) is observed in patients with MM who are treated (or have been treated) with such a combination therapy. This article reports the case of a 72-year-old male patient, who suffered from such a pathological condition under treatment with binimetinib in combination with nivolumab. This case study illustrates the importance of interdisciplinary collaboration in the treatment of MM patients.


Assuntos
Melanoma , Doenças Retinianas , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Benzimidazóis/uso terapêutico , Humanos , Masculino , Melanoma/tratamento farmacológico , Quinases de Proteína Quinase Ativadas por Mitógeno/uso terapêutico , Mutação
18.
Jpn J Clin Oncol ; 40(2): 139-45, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19837687

RESUMO

OBJECTIVE: Autofluorescence imaging (AFI) videobronchoscopy is a new endoscopic tool that improves visualization of neoplastic changes in the bronchial mucosa. The major aim of our study was to determine sensitivity and specificity of the technique in the assessment of tumor extent (margins). The secondary objective was to evaluate the possible effect of AFI on the change in therapeutic decisions of lung cancer treatment. METHODS: In this prospective trial, we enrolled 104 patients in whom we performed 624 targeted biopsies, 3 from the pathologically altered mucosa (red-brownish or magenta colored) and 3 from randomly picked normal areas. We were using the Olympus BF-F260 videobronchoscope and EVIS LUCERA system. White light videobronchoscopy (WLB) preceded AFI examination and biopsy collection. All biopsy specimens were examined by a pathologist blinded to bronchoscopy findings, and where applicable surgically resected specimens were examined. RESULTS: In 14.4% of the patients, AFI revealed a greater extent of the tumor than WLB, and in 11.5% that finding led to change in therapeutic decision (lesser or greater resection or avoidance of surgery). We found a significant correlation between tumor extent determined by AFI and changes in therapeutic decisions (P < 0.01). Sensitivity, specificity, positive predictive value and negative predictive value for AFI in the assessment of tumor extension were 93%, 92%, 92% and 93%, respectively. Corresponding results for WLB were 84%, 79%, 77% and 85%, respectively. Relative sensitivity of AFI is 1.11. CONCLUSIONS: Our results confirm that AFI videobronchoscopy significantly improves the assessment of central lung cancer extension and influences the therapeutic strategy. This technique has greater sensitivity and specificity, in assessment of tumor margins, than WLB alone.


Assuntos
Adenocarcinoma/diagnóstico , Broncoscopia , Fluorescência , Neoplasias Pulmonares/diagnóstico , Gravação em Vídeo , Adulto , Idoso , Idoso de 80 Anos ou mais , Broncoscopia/métodos , Diagnóstico por Imagem/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Lesões Pré-Cancerosas/diagnóstico , Sensibilidade e Especificidade , Fumar , Tomografia de Coerência Óptica , Gravação em Vídeo/métodos
19.
Scand J Med Sci Sports ; 20(3): 485-92, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19558385

RESUMO

The macroscopic contact area between ski and snow and the contact pressure are crucial influencing factors for carved turns in Alpine skiing. In the present paper, a simulation model is developed to quantify these factors. The ski is modelled as an Euler-Bernoulli beam with variable cross section, camber, bending and torsional stiffness using measured data from skis. The reaction forces of the snow are decomposed in penetration and shear forces. For the penetration forces a hypoplastic constitutive law is applied incorporating elastic and plastic deformation of the snow at the contact area. For the shear forces metal cutting theory is used. Ski deformation, contact area and contact pressure are computed based on quasi-static equilibrium between forces exerted by the skier and snow reaction forces. Parameter studies are performed to investigate the influence of edging and distributing the load between the inner and outer ski. Higher edging angles as well as loading both skis affected the contact pressure positively by increasing the resistance against shearing. The results of our study agree well with measurement data taken from literature. Based on the results, the importance of actions of the skier during carved turns is concluded.


Assuntos
Desenho de Equipamento , Esqui , Equipamentos Esportivos , Algoritmos , Fricção , Humanos , Modelos Teóricos
20.
Jpn J Clin Oncol ; 39(10): 657-63, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19648589

RESUMO

OBJECTIVE: Narrow band imaging (NBI) videobronchoscopy is a new technique aimed at lung cancer detection. This study investigated its sensitivity and specificity for evaluation of lung cancer extension and its possible influence on therapeutic decision, compared with white light videobronchoscopy. METHODS: In this prospective study, we evaluated 106 patients with suspected lung cancer. All patients were examined using EVIS LUCERA videoendoscopy system. In every patient, at least three biopsies were taken from places visualized as pathologic, surrounding primary tumor, and three biopsies from places that appeared normal. The overall number of biopsies performed in 106 patients was 636. RESULTS: The specificity and sensitivity of NBI in revealing greater lung cancer extension were 85.6% and 95%, respectively; positive and negative predictive values were 84% and 95.6%, respectively. Specificity and sensitivity were significantly better when compared with white light bronchoscopy alone (P < 0.01). NBI led to the change in therapeutic decision in 14 patients. There was statistically significant correlation between NBI assessment of tumor extension and change in therapeutic decision (P < 0.000). CONCLUSIONS: NBI showed significantly better specificity and sensitivity in the assessment of lung cancer extension. NBI proved that it might have potential influence on therapeutic decision, making it more accurate. The procedure is safe and easily deployed in everyday practice.


Assuntos
Broncoscopia/métodos , Carcinoma de Células Escamosas/diagnóstico , Diagnóstico por Imagem/métodos , Neoplasias Pulmonares/diagnóstico , Gravação em Vídeo , Adulto , Idoso , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Feminino , Humanos , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/terapia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias
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