Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 127
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Rev Environ Contam Toxicol ; 241: 139-160, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27300012

RESUMO

Application of radioactive elements or radionuclides for anthropogenic use is a widespread phenomenon nowadays. Radionuclides undergo radioactive decays releasing ionizing radiation like gamma ray(s) and/or alpha or beta particles that can displace electrons in the living matter (like in DNA) and disturb its function. Radionuclides are highly hazardous pollutants of considerable impact on the environment, food chain and human health. Cleaning up of the contaminated environment through plants is a promising technology where the rhizosphere may play an important role. Plants belonging to the families of Brassicaceae, Papilionaceae, Caryophyllaceae, Poaceae, and Asteraceae are most important in this respect and offer the largest potential for heavy metal phytoremediation. Plants like Lactuca sativa L., Silybum marianum Gaertn., Centaurea cyanus L., Carthamus tinctorius L., Helianthus annuus and H. tuberosus are also important plants for heavy metal phytoremediation. However, transfer factors (TF) of radionuclide from soil/water to plant ([Radionuclide]plant/[Radionuclide]soil) vary widely in different plants. Rhizosphere, rhizobacteria and varied metal transporters like NRAMP, ZIP families CDF, ATPases (HMAs) family like P1B-ATPases, are involved in the radio-phytoremediation processes. This review will discuss recent advancements and potential application of plants for radionuclide removal from the environment.


Assuntos
Plantas/metabolismo , Poluentes Radioativos/farmacocinética , Biodegradação Ambiental , Disponibilidade Biológica , Transporte Biológico , Poluentes Radioativos do Solo/farmacocinética
2.
Protein Expr Purif ; 120: 42-50, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26687898

RESUMO

N(pro) fusion technology, a highly efficient system for overexpression of proteins and peptides in Escherichia coli, was further developed by splitting the autoprotease N(pro) into two fragments to generate a functional complementation system. The size of the expression tag is thus reduced from 168 to 58 amino acids, so by 66%. Upon complementation of the fragments auto-proteolytic activity is restored. This process has been shown for three model proteins of different size, a short 16 aa-peptide, MCP-1, and lysozyme. Moreover, the complementation was still functional after immobilization of the N-terminal fragment to a solid support which enables recycling of the immobilized fragment. This strategy enhances overall productivity of N(pro) Fusion Technology and thus allows more efficient production of recombinant proteins with reduced costs and in higher yields. Overall, the N(pro) complementation system has, depending on the size of the target molecule, potential to increase the productivity up to 4 fold for batch refolding and even more for on-column refolding strategies by the proven possibility of regeneration of the immobilized fragment.


Assuntos
Escherichia coli/genética , Peptídeo Hidrolases , Proteínas Recombinantes de Fusão/isolamento & purificação , Regulação para Cima , Sequência de Aminoácidos , Quimiocina CCL2/isolamento & purificação , Quimiocina CCL2/metabolismo , Cromatografia de Afinidade , Escherichia coli/metabolismo , Dados de Sequência Molecular , Muramidase/isolamento & purificação , Muramidase/metabolismo , Peptídeos/isolamento & purificação , Peptídeos/metabolismo , Redobramento de Proteína , Proteínas Recombinantes de Fusão/metabolismo
3.
Arch Gynecol Obstet ; 293(2): 383-9, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26193954

RESUMO

PURPOSE: To analyze the trends and developments among journals in the specialty of obstetrics and gynecology. METHODS: Using the Journal Citation Reports from 2007 to 2013, we analyzed the impact factor (IF), Eigenfactor® Score (ES), and Article Influence® Score (AIS) of 43 journals in the field of obstetrics and gynecology published in this time period. RESULTS: From 78 journals of the Journal Citation Report 2013, 43 were selected for this study. The mean IF grew from 1.68 ± 0.97 in 2007 to 2.12 ± 1.05 in 2013, the ES from 0.0113 ± 0.0169 to 0.0114 ± 0.0140, and the AIS from 0.513 ± 0.302 to 0.663 ± 0.359. Differences in the IF, ES, and AIS between journals from the United States versus Europe could be observed. In most cases, the IF, ES, and AIS increased between 2007 and 2013. Strong correlations could be found between IF, AIS, and ES. CONCLUSIONS: The overall mean IF for obstetrical and gynecological journals increased over the analyzed time period. The IF remains the standard measure to compare scientific journals. It correlates well with two major alternative measures of scientific impact, the ES and especially the AIS. Other measures are evolving and might show superior usage in the future.


Assuntos
Ginecologia/tendências , Fator de Impacto de Revistas , Obstetrícia/tendências , Publicações Periódicas como Assunto/estatística & dados numéricos , Editoração/tendências , Bibliometria , Feminino , Humanos , Gravidez , Editoração/estatística & dados numéricos , Estados Unidos
4.
Int J Cancer ; 136(3): 699-708, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-24895230

RESUMO

This phase I study tested the safety, feasibility, pharmacokinetics and pharmacodynamics of cisplatin administered as hyperthermic intraoperative intraperitoneal chemoperfusion (HIPEC) in patients with platinum-sensitive recurrent epithelial ovarian cancer (EOC) undergoing secondary cytoreductive surgery followed by postoperative platinum-based intravenous chemotherapy. Twelve patients with operable, recurrent platinum-sensitive EOC (recurrence ≥6 months after first-line therapy) were included according to the classical 3+3 dose-escalation design at three dose levels-60, 80 and 100 mg/m(2). After surgical cytoreduction, a single dose of cisplatin was administered via HIPEC for 90 min at 41-43°C. Postoperatively, all patients were treated with standard intravenous platinum-based combination chemotherapy. One of six patients experienced a dose-limiting toxicity (grade 3 renal toxicity) at a dose of 100 mg/m(2). The remaining five patients treated with 100 mg/m(2) tolerated their treatment well. The recommended phase II dose was established at 100 mg/m(2). The mean peritoneal-to-plasma AUC ratio was 19·5 at the highest dose level. Cisplatin-induced DNA adducts were confirmed in tumor samples. Common postoperative grade 1-3 toxicities included fatigue, postoperative pain, nausea, and surgical site infection. The ability to administer standard intravenous platinum-based chemotherapy after HIPEC was uncompromised. Cisplatin administered as HIPEC at a dose of 100 mg/m(2) has an acceptable safety profile in selected patients undergoing secondary cytoreductive surgery for platinum-sensitive recurrent EOC. Favorable pharmacokinetic and pharmacodynamic properties of HIPEC with cisplatin were confirmed at all dose levels, especially at 100 mg/m(2). The results are encouraging to determine the efficacy of HIPEC as a complementary treatment in patients with EOC.


Assuntos
Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Cisplatino/administração & dosagem , Procedimentos Cirúrgicos de Citorredução/métodos , Hipertermia Induzida , Recidiva Local de Neoplasia/terapia , Neoplasias Epiteliais e Glandulares/terapia , Neoplasias Ovarianas/terapia , Adulto , Idoso , Carcinoma Epitelial do Ovário , Cisplatino/efeitos adversos , Cisplatino/análise , Cisplatino/farmacocinética , Terapia Combinada , Adutos de DNA/análise , Feminino , Humanos , Pessoa de Meia-Idade
5.
J Radiol Prot ; 34(3): 575-93, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24983208

RESUMO

Despite several decades of studies on the risk assessment and risk perception of ionising radiation, risk management of radioactive materials remains a challenging issue. This is also true for wastes containing technologically enhanced naturally occurring radioactive materials. The present work focuses on the underlying reasons for communication problems between experts and affected members of the public. Exploring the case of a German remediation site with residual radioactive contamination in a residential area, the experts' as well as the residents' perspectives were studied by conducting qualitative interviews. Our results indicate a variety of reasons for communication problems on different levels of risk management and risk communication: the regulatory, the communicative and the moral levels. In the observed case, four salient causes for problems in risk communication and risk management emerged: the mismatch in understanding the residents' values, the issue of risk communication in an unforeseen situation, the problem of the regulatory gap between radiation protection and soil protection in regard to legacies with naturally occurring radioactive material in Germany, and the challenge of communicating a highly complex scientific issue to non-scientists. Moreover, one (at least partial) solution could be seen: the introduction of an external mediator. The results indicate that coordination of different health and environment protection disciplines-in this case radiation protection relating to soil protection-is possible and urgently needed. The opportunity to put, at least natural, radioactive material in line with other conventional industrial materials should be taken.


Assuntos
Recuperação e Remediação Ambiental/legislação & jurisprudência , Proteção Radiológica/legislação & jurisprudência , Poluentes Radioativos do Solo , Acesso à Informação , Comunicação , Alemanha , Humanos , Medição de Risco
6.
Adv Healthc Mater ; 12(27): e2301194, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37171457

RESUMO

Tumor-derived extracellular vesicles (TEVs) induce the epithelial-to-mesenchymal transition (EMT) in nonmalignant cells to promote invasion and cancer metastasis, representing a novel therapeutic target in a field severely lacking in efficacious antimetastasis treatments. However, scalable technologies that allow continuous, multiparametric monitoring for identifying metastasis inhibitors are absent. Here, the development of a functional phenotypic screening platform based on organic electrochemical transistors (OECTs) for real-time, noninvasive monitoring of TEV-induced EMT and screening of antimetastatic drugs is reported. TEVs derived from the triple-negative breast cancer cell line MDA-MB-231 induce EMT in nonmalignant breast epithelial cells (MCF10A) over a nine-day period, recapitulating a model of invasive ductal carcinoma metastasis. Immunoblot analysis and immunofluorescence imaging confirm the EMT status of TEV-treated cells, while dual optical and electrical readouts of cell phenotype are obtained using OECTs. Further, heparin, a competitive inhibitor of cell surface receptors, is identified as an effective blocker of TEV-induced EMT. Together, these results demonstrate the utility of the platform for TEV-targeted drug discovery, allowing for facile modeling of the transient drug response using electrical measurements, and provide proof of concept that inhibitors of TEV function have potential as antimetastatic drug candidates.


Assuntos
Neoplasias da Mama , Vesículas Extracelulares , Neoplasias de Mama Triplo Negativas , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Detecção Precoce de Câncer , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia , Transição Epitelial-Mesenquimal/genética , Movimento Celular , Melanoma Maligno Cutâneo
7.
Nat Commun ; 14(1): 653, 2023 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-36746944

RESUMO

The detection of proteins is of central importance to biomolecular analysis and diagnostics. Typical immunosensing assays rely on surface-capture of target molecules, but this constraint can limit specificity, sensitivity, and the ability to obtain information beyond simple concentration measurements. Here we present a surface-free, single-molecule microfluidic sensing platform for direct digital protein biomarker detection in solution, termed digital immunosensor assay (DigitISA). DigitISA is based on microchip electrophoretic separation combined with single-molecule detection and enables absolute number/concentration quantification of proteins in a single, solution-phase step. Applying DigitISA to a range of targets including amyloid aggregates, exosomes, and biomolecular condensates, we demonstrate that the assay provides information beyond stoichiometric interactions, and enables characterization of immunochemistry, binding affinity, and protein biomarker abundance. Taken together, our results suggest a experimental paradigm for the sensing of protein biomarkers, which enables analyses of targets that are challenging to address using conventional immunosensing approaches.


Assuntos
Técnicas Biossensoriais , Técnicas Biossensoriais/métodos , Imunoensaio , Biomarcadores/análise , Amiloide , Microfluídica/métodos
8.
Rapid Commun Mass Spectrom ; 26(6): 583-91, 2012 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-22328210

RESUMO

Polymerization in hexavalent uranium solutions was measured by electrospray ionization time-of-flight mass spectrometry in three different acidic media at pH values from 3 to 5.3 in order to detect all hydrolysis species present in solution. The aqueous solutions were directly measured without further dilution in organic solvents. At high uranyl concentrations ([U(VI)] = 10(- 3) M) artifacts were observed due to the presence of more than one solution species per formed microdroplet. Those artifacts were composed of ions and neutral species being present in the same droplet. However, by analyzing the detected species carefully, the origin of the artifacts could be traced back to the physically meaningful species. Still, only general trends of the hydrolysis behavior can be deduced from the measurements at [U(VI)] = 1 ⋅ 10(- 3) M. The solutions at [U(VI)] = 5 ⋅ 10(- 5) M did not show any comparable artifact formation. The detected species distributions resemble the expected trends calculated from the equilibrium constants published in the Nuclear Energy Agency Thermodynamic Database (NEA-TDB). The neutral (UO(2))(CO(3))(0) species present in solution causes, if located in the same microdroplet as a charged species, the apparent formation of dimeric and trimeric ternary hydroxo carbonate complexes at pH 5.3. As the uncharged species is not repelled from the ionic species, it might remain in the same droplet during the droplet fission process. By dividing those detected species into the uncharged (UO(2))(CO(3))(0) and a second ionic species, the relative abundances of the solution species can be corrected, leading to a good agreement with the predictions of the published equilibrium constants. In addition to the well-known trimer, we report the direct mass spectrometric detection of the dimeric (UO(2))(2)(OH)(2)(2+) species.

9.
Acta Anaesthesiol Scand ; 56(8): 1066-8, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22762373

RESUMO

We report a patient with severe anaphylactic shock immediately after injection of i.v. fluorescein. The patient recovered without sequela. Immunoglobulin E (IgE) mechanism was highly suggestive with significant increase in serum tryptase, positive basophil allergen threshold sensitivity (CD-sens) and histamine release tests towards fluorescein. This is, to our knowledge, the first report where CD-sens has been used to aid in diagnosing an IgE-mediated anaphylactic shock caused by fluorescein.


Assuntos
Anafilaxia/imunologia , Meios de Contraste/efeitos adversos , Fluoresceína/efeitos adversos , Imunoglobulina E/imunologia , Idoso , Anafilaxia/tratamento farmacológico , Anafilaxia/etiologia , Antígenos CD/imunologia , Basófilos/imunologia , Dor no Peito/complicações , Epinefrina/uso terapêutico , Liberação de Histamina/fisiologia , Humanos , Intubação Intratraqueal , Masculino , Muco/fisiologia , Testes Cutâneos , Triptases , Vasoconstritores/uso terapêutico
10.
BMC Cancer ; 11: 335, 2011 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-21816051

RESUMO

BACKGROUND: Male breast cancer (MBC) is a rare disease accounting for approximately 1% of all breast carcinomas. Presently treatment recommendations are derived from the standards for female breast cancer. However, those approaches might be inadequate because of distinct gender specific differences in tumor biology of breast cancer. This study was planned in order to contrast potential differences between female and male breast cancer in both tumor biological behavior and clinical management. METHODS: MBC diagnosed between 1995-2007 (region Chemnitz/Zwickau, Saxony, Germany) was retrospectively analyzed. Tumor characteristics, treatment and follow-up of the patients were documented. In order to highlight potential differences each MBC was matched with a female counterpart (FBC) that showed accordance in at least eight tumor characteristics (year of diagnosis, age, tumor stage, nodal status, grade, estrogen- and progesterone receptors, HER2 status). RESULTS: 108 male/female matched-pairs were available for survival analyses. In our study men and women with breast cancer had similar disease-free (DFS) and overall (OS) survival. The 5-years DFS was 53.4% (95% CI, range 54.1-66.3) in men respectively 62.6% (95% CI, 63.5-75.3) in women (p > 0.05). The 5-years OS was 71.4% (95% CI, 62.1-72.7%) and 70.3% (95% CI, 32.6-49.6) in women (p > 0.05). In males DFS analyses revealed progesterone receptor expression as the only prognostic relevant factor (p = 0.006). In multivariate analyses for OS both advanced tumor size (p = 0.01) and a lack of progesterone receptor expression were correlated (p = 0.01) with poor patients outcome in MBC. CONCLUSION: Our comparative study revealed no survival differences between male and female breast cancer patients and gives evidence that gender is no predictor for survival in breast cancer. This was shown despite of significant gender specific differences in terms of frequency and intensity of systemic therapy in favor to female breast cancer.


Assuntos
Neoplasias da Mama Masculina/patologia , Neoplasias da Mama/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/metabolismo , Neoplasias da Mama/terapia , Neoplasias da Mama Masculina/metabolismo , Neoplasias da Mama Masculina/terapia , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Linfonodos/patologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estadiamento de Neoplasias , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento , Carga Tumoral
11.
ACS Nano ; 15(11): 18142-18152, 2021 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-34694775

RESUMO

Emerging viruses will continue to be a threat to human health and wellbeing into the foreseeable future. The COVID-19 pandemic revealed the necessity for rapid viral sensing and inhibitor screening in mitigating viral spread and impact. Here, we present a platform that uses a label-free electronic readout as well as a dual capability of optical (fluorescence) readout to sense the ability of a virus to bind and fuse with a host cell membrane, thereby sensing viral entry. This approach introduces a hitherto unseen level of specificity by distinguishing fusion-competent viruses from fusion-incompetent viruses. The ability to discern between competent and incompetent viruses means that this device could also be used for applications beyond detection, such as screening antiviral compounds for their ability to block virus entry mechanisms. Using optical means, we first demonstrate the ability to recapitulate the entry processes of influenza virus using a biomembrane containing the viral receptor that has been functionalized on a transparent organic bioelectronic device. Next, we detect virus membrane fusion, using the same, label-free devices. Using both reconstituted and native cell membranes as materials to functionalize organic bioelectronic devices, configured as electrodes and transistors, we measure changes in membrane properties when virus fusion is triggered by a pH drop, inducing hemagglutinin to undergo a conformational change that leads to membrane fusion.


Assuntos
COVID-19 , Nanopartículas , Vírus , Humanos , Pandemias , Internalização do Vírus
12.
ACS Biomater Sci Eng ; 7(12): 5585-5597, 2021 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-34802228

RESUMO

Cancer-derived exosomes (cEXOs) facilitate transfer of information between tumor and human primary stromal cells, favoring cancer progression. Although the mechanisms used during this information exchange are still not completely understood, it is known that binding is the initial contact established between cEXOs and cells. Hence, studying binding and finding strategies to block it are of great therapeutic value. However, such studies are challenging for a variety of reasons, including the need for human primary cell culture, the difficulty in decoupling and isolating binding from internalization and cargo delivery, and the lack of techniques to detect these specific interactions. In this work, we created a supported biomimetic stem cell membrane incorporating membrane components from human primary adipose-derived stem cells (ADSCs). We formed the supported membrane on glass and on multielectrode arrays to offer the dual option of optical or electrical detection of cEXO binding to the membrane surface. Using our platform, we show that cEXOs bind to the stem cell membrane and that binding is blocked when an antibody to integrin ß1, a component of ADSC surface, is exposed to the membrane surface prior to cEXOs. To test the biological outcome of blocking this interaction, we first confirm that adding cEXOs to cultured ADSCs leads to the upregulation of vascular endothelial growth factor, a measure of proangiogenic activity. Next, when ADSCs are first blocked with anti-integrin ß1 and then exposed to cEXOs, the upregulation of proangiogenic activity and cell proliferation are significantly reduced. This biomimetic membrane platform is the first cell-free label-free in vitro platform for the recapitulation and study of cEXO binding to human primary stem cells with potential for therapeutic molecule screening as it is compatible with scale-up and multiplexing.


Assuntos
Exossomos , Neoplasias , Biomimética , Humanos , Células-Tronco , Fator A de Crescimento do Endotélio Vascular
13.
Cancer Immunol Immunother ; 59(6): 909-19, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20087581

RESUMO

Preoperative neoadjuvant chemotherapy (NAC) can significantly reduce tumour burden in patients with primarily unresectable chemosensitive tumours, allowing a more complete cytoreduction during debulking surgery and facilitating evaluation of tumour chemosensitivity, identification of appropriate treatment options and improvement of intervention protocols. In this study, we investigate, using immunohistochemistry, the impact of platinum/taxane-based NAC (NAC) on tumour-infiltrating lymphocytes (TILs) in advanced epithelial ovarian cancer (EOC) and their relationship with clinical outcome. All patients had clinical response, as shown by ascites volume and CA125 levels compared to pre-treatment findings. NAC intervention significantly increased CD4(+), CD8(+) and granzyme B(+) infiltration while Foxp3(+) accumulation remained unaffected. TILs were prognostically neutral for both progression-free survival (PFS) and overall survival (OS) before NAC. In contrast, after NAC, elevated granzyme B(+) infiltration displayed a tendency for improved PFS (log-rank 0.064). Further, low Foxp3(+) cell density was associated with longer PFS, as compared with strong Foxp3(+) infiltration (median 20.94 vs. 11.24 months; log-rank 0.0001) and with improved OS (median 30.75 vs. 16.04 months, respectively; log-rank 0.056), demonstrating clear prognostic significance for PFS. In addition, high granzyme B(+)/Foxp3(+) ratio post-NAC strongly correlated with improved PFS compared to low granzyme B(+)/Foxp3(+) cell ratio (median 17.88 vs. 11.24 months, respectively), and showed to be a favourable prognostic factor for PFS (log-rank 0.014). Our findings indicate that NAC elicited an immunologic profile in which low immunosuppressive Foxp3(+) infiltration and elevated numbers of activated granzyme B(+) cells were significantly associated with EOC-specific PFS, suggesting a contribution of immunologic effects to improved clinical outcome.


Assuntos
Terapia Neoadjuvante , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/biossíntese , Movimento Celular/efeitos dos fármacos , Movimento Celular/imunologia , Progressão da Doença , Feminino , Fatores de Transcrição Forkhead/biossíntese , Granzimas/biossíntese , Humanos , Imuno-Histoquímica , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Linfócitos do Interstício Tumoral/patologia , Pessoa de Meia-Idade , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/fisiopatologia , Compostos de Platina/administração & dosagem , Compostos de Platina/efeitos adversos , Prognóstico , Taxoides/administração & dosagem , Taxoides/efeitos adversos , Resultado do Tratamento
14.
Opt Express ; 18(8): 8043-52, 2010 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-20588648

RESUMO

Laser emission over a broad range of frequencies from 2.8 to 4.1 THz is reported for a two-quantum well, photon-phonon cascade structure. Maximum operating temperatures of 125 K are reported, with optical peak powers in eccess of 30 mW from a double-metal ridge waveguide. The broadband nature of the gain curve is identified as due to coherent coupling of the injector and upper lasing states. Internal quantum efficiencies reaching 43 % are evaluated at 10 K.The laser operates in both polarities, showing laser action in reverse bias up to a temperature of 90 K. Simulations based on a full treatment of the structure with density matrix formalism are also presented and discussed.

15.
Methods Find Exp Clin Pharmacol ; 32(8): 585-91, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21132128

RESUMO

The influences of both being in a supine position for a prolonged period and food intake on cardiovascular variables were studied under clinical-pharmacological test conditions. In a randomized crossover design study without drug or placebo administration, 6 healthy male volunteers received a light standard meal before and during test A and fasted in test B. In both tests, while they were continuously supine for more than 8 h, a synchronous recording of cardiovascular variables was done at 24, 26 and 28 min after starting the supine position (first recordings) and 25 times from 2 to 480 min after the first recordings. Using a multifactorial statistical analysis, each parameter was evaluated regarding the factors eating and time of supine recording. Eating led to a significant decrease in diastolic and mean blood pressure, PQ time and QS2 time, a downward trend in systemic vascular resistance and an upward trend in systolic blood pressure and cardiac output. When the subjects remained in a supine position for prolonged periods, significant increases in systolic, diastolic, mean blood pressure and systemic vascular resistance were noted as well as significant decreases in cardiac output and QS2 time. Thus, eating and remaining in a supine position for prolonged periods should be considered as sources of bias in clinical-pharmacological studies on cardiovascular drug effects and accompanying placebo controls.


Assuntos
Pressão Sanguínea/fisiologia , Ingestão de Alimentos/fisiologia , Frequência Cardíaca/fisiologia , Decúbito Dorsal/fisiologia , Adulto , Débito Cardíaco/fisiologia , Estudos Cross-Over , Interpretação Estatística de Dados , Humanos , Masculino , Fatores de Tempo , Resistência Vascular/fisiologia , Adulto Jovem
16.
Int J Cardiol Heart Vasc ; 31: 100641, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33088899

RESUMO

BACKGROUND: MitraClip ® (MC) is an established procedure for severe mitral regurgitation (MR) in patients deemed unsuitable for surgery.Right ventricular dysfunction (RVD) is associated with a higher mortality risk. The prognostic accuracy of heart failure risk scores like the Seattle heart failure model (SHFM) and Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score in pts undergoing MC with or without RVD has not been investigated so far. METHODS: SHFM and MAGGIC score were calculated retrospectively. RVD was determined as tricuspid annular plane systolic excursion (TAPSE) ≤15 mm. Area under receiver operating curves (AUROC) of SHFM and MAGGIC were performed for one-year all-cause mortality after MC. RESULTS: N = 103 pts with MR III° (73 ± 11 years, LVEF 37 ± 17%) underwent MC with a reduction of at least I° MR. One-year mortality was 28.2%.In Kaplan-Meier analysis, one- year mortality was significantly higher in RVD-pts (34.8% vs 2.8%, p = 0.009).Area under the Receiver Operating Characteristic (AUROC) for SHFM and MAGGIC were comparable for both scores (SHFM: 0.704, MAGGIC: 0.692). In pts without RVD, SHFM displayed a higher AUROC and therefore better diagnostic accuracy (SHFM: 0.776; MAGGIC: 0.551, p < 0.05). In pts with RVD, MAGGIC and SHFM displayed comparable AUROCs. CONCLUSION: RVD is an important prognostic marker in pts undergoing MC. SHFM and MAGGIC displayed adequate over-all prognostic power in these pts. Accuracy differed in pts with and without RVD, indicating higher predictive power of the SHFM score in pts without RVD.

17.
Opt Express ; 17(3): 1159-68, 2009 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-19188942

RESUMO

We demonstrate for the first time the closure of an electronic phase lock loop for a continuous-wave quantum cascade laser (QCL) at 1.5 THz. The QCL is operated in a closed cycle cryo cooler. We achieved a frequency stability of better than 100 Hz, limited by the resolution bandwidth of the spectrum analyser. The PLL electronics make use of the intermediate frequency (IF) obtained from a hot electron bolometer (HEB) which is downconverted to a PLL IF of 125 MHz. The coarse selection of the longitudinal mode and the fine tuning is achieved via the bias voltage of the QCL. Within a QCL cavity mode, the free-running QCL shows frequency fluctuations of about 5 MHz, which the PLL circuit is able to control via the Stark-shift of the QCL gain material. Temperature dependent tuning is shown to be nonlinear, and of the order of -16 MHz/K. Additionally we have used the QCL as local oscillator (LO) to pump an HEB and perform, again for the first time at 1.5 THz, a heterodyne experiment, and obtain a receiver noise temperature of 1741 K.

18.
J Cell Biol ; 78(3): 839-55, 1978 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29904

RESUMO

Retractor unguis nerve muscle preparations from the locust were subjected to the zinc iodide-osmium tetroxide reaction (ZIO) after pre-fixation in glutaraldehyde. Applied for 18 h at 4 degrees C in the dark, ZIO reacts at pH 4.2--4.0 fairly selectively with the matrix of synaptic vesicles. Approximately 53% of the vesicles are completely and 4% partially stained. The percentage of ZIO-positive vesicles is increased to nearly 90% and reduced to 4% or less by pretreatment with SH-protecting (dithiothreitol) or SH-blocking (N-ethylmaleimide, p-chloromercuriphenyl sulfonic acid) and SH-oxidizing (azodicarboxylic acid-bis-dimethylamide) reagents, respectively. Stimulation of the motor nerve at 20 Hz for 7 min, partially fatiguing synaptic transmission, reduces the number of vesicles per square micrometer of terminal area by approximately 52%; 2 min of rest restores this number of its pre-stimulation level. These changes are chiefly accounted for by changes in the number of completely ZIO-positive vesicles. 2 min after the end of stimulation, partially ZIO-positive vesicles are three times more frequent than before. With all experimental conditions, the average volume of vesicles was as follows: ZIO-negative less than partially ZIO-positive less than completely ZIO-positive. The average volume of ZIO-positive vesicles is almost unaffected by stimulation; that of ZIO-negative vesicles is decreased by 25% immediately after stimulation, increasing with subsequent rest to the initial level after 1 h. It is suggested (a) that ZIO demonstrates intravesicular protein(s) containing SH-groups and (b) that the completely ZIO-positive vesicles represent the mature ones ready to be used for transmitter release. How the ZIO reaction differentiates between different developmental stages of vesicles which could arise from the smooth endoplasmic reticulum is discussed.


Assuntos
Junção Neuromuscular/ultraestrutura , Vesículas Sinápticas/metabolismo , Animais , Diamida/farmacologia , Ditiotreitol/farmacologia , Gafanhotos , Histocitoquímica , Concentração de Íons de Hidrogênio , Morfogênese , Junção Neuromuscular/fisiologia , Osmio , Ácido Tricloroacético/farmacologia , Zinco
19.
J Electrocardiol ; 42(2): 139-44, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19159901

RESUMO

BACKGROUND: After an acute myocardial infarction (MI), it is important to define the infarct size because it is related to mortality and morbidity. The Selvester QRS Score is an electrocardiographic (ECG) method that has been developed for estimating MI size. It has been shown to correlate well with postmortem anatomically measured sizes of single MI in patients who did not receive thrombolytic therapy. The aim of this study was to test the hypothesis that correlation between Selvester QRS Score-estimated MI size and contrast-enhanced magnetic resonance imaging (ceMRI)-measured MI size is equivalent in patients who did vs those who did not receive thrombolytic therapy. METHODS: Thirty-six patients with MI (24 with thrombolytic therapy and 12 without) received ceMRI and ECG at admission and at 1 or 6 months after admission. Indeed, in 23 of the patients, the therapy was intravenous only. The Selvester QRS Score was calculated using the 1-month ECG or, if not available, the 6-month ECG. The correlation between the 2 measures of MI size was determined for all patients and for the 2 groups separately. RESULTS: The mean MI size in the group that did not receive thrombolytic therapy was 8.5% +/- 6.4% estimated by the Selvester QRS Score and 11.7% +/- 10.2% measured by ceMRI. For the group that received thrombolytic therapy, Selvester QRS Score was 13.9% +/- 11.1% and ceMRI was 20.2% +/- 11.3%. The mean MI size in both groups combined was 12.1% +/- 10.0% estimated by the Selvester QRS Score and 17.3% +/- 11.5% measured by ceMRI. The Spearman rank correlation coefficient between Selvester QRS Score and ceMRI was 0.74 (P < .0001) for all patients, 0.74 (P < .0001) for the group that received thrombolytic therapy, and 0.64 (P = .024) for the group that did not receive thrombolytic therapy. CONCLUSIONS: The associations between Selvester QRS Score and ceMRI-based MI were statistically significant and similar in both groups.


Assuntos
Eletrocardiografia/métodos , Imageamento por Ressonância Magnética/métodos , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/terapia , Índice de Gravidade de Doença , Terapia Trombolítica/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste , Feminino , Humanos , Aumento da Imagem/métodos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estatística como Assunto
20.
J Colloid Interface Sci ; 318(1): 5-14, 2008 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-17964592

RESUMO

The adsorption of Cm(III) on quartz is studied by time resolved laser fluorescence spectroscopy (TRLFS) in the pH range from 3.75 to 9.45. The raw spectra are deconvoluted into three single components. The first one has a peak maximum at 593.8 nm and can be attributed to the Cm(III) aquo ion with an emission lifetime of 68+/-3 micros. The second one corresponds to an adsorbed species and has a peak maximum at 601.4 nm and an emission lifetime of 123+/-10 micros. The peak maximum of the third component is shifted to higher wavelength (603.6 nm) while the lifetime remains constant. Additionally, the adsorption of Am(III) on quartz is investigated in batch experiments. Based on the spectroscopic data a sorption mechanism is suggested. In addition, the obtained Am uptake data and the Cm-TRLFS data are modeled simultaneously using a single site Basic Stern model in combination with the charge distribution concept of Pauling. The finally suggested model consists of two bidentate surface complexes where the second one is the product of hydrolysis of the first sorption species. In a separate set of experiments the influence of silicic acid at different concentrations on the Cm(III) speciation in a quartz system is investigated by TRLFS. In suspension silicic acid at low concentration (3.5x10(-4) mol/L) has no influence on the Cm(III) speciation. At high concentration (3.5x10(-2) mol/L) the Cm(III) speciation is definitely influenced. The results at higher concentration indicate the formation of Cm(III)/silicic acid complexes and the incorporation of Cm(III) into siliceous bulk. This is confirmed by measurements at a quartz single crystal surface. Moreover, these measurements indicate the formation of quartz/Cm(III)/silicic acid ternary complexes at the mineral surface.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA