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1.
Phys Rev Lett ; 131(2): 027001, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37505965

RESUMO

The macroscopic coherence in superconductors supports dissipationless supercurrents that could play a central role in emerging quantum technologies. Accomplishing unequal supercurrents in the forward and backward directions would enable unprecedented functionalities. This nonreciprocity of critical supercurrents is called the superconducting (SC) diode effect. We demonstrate the strong SC diode effect in conventional SC thin films, such as niobium and vanadium, employing external magnetic fields as small as 1 Oe. Interfacing the SC layer with a ferromagnetic semiconductor EuS, we further accomplish the nonvolatile SC diode effect reaching a giant efficiency of 65%. By careful control experiments and theoretical modeling, we demonstrate that the critical supercurrent nonreciprocity in SC thin films could be easily accomplished with asymmetrical vortex edge and surface barriers and the universal Meissner screening current governing the critical currents. Our engineering of the SC diode effect in simple systems opens the door for novel technologies while revealing the ubiquity of the Meissner screening effect induced SC diode effect in superconducting films, and it should be eliminated with great care in the search for exotic superconducting states harboring finite-momentum Cooper pairing.

2.
Nano Lett ; 22(17): 7049-7056, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-35998346

RESUMO

PbTe is a semiconductor with promising properties for topological quantum computing applications. Here, we characterize electron quantum dots in PbTe nanowires selectively grown on InP. Charge stability diagrams at zero magnetic field reveal large even-odd spacing between Coulomb blockade peaks, charging energies below 140 µeV and Kondo peaks in odd Coulomb diamonds. We attribute the large even-odd spacing to the large dielectric constant and small effective electron mass of PbTe. By studying the Zeeman-induced level and Kondo splitting in finite magnetic fields, we extract the electron g-factor as a function of magnetic field direction. We find the g-factor tensor to be highly anisotropic with principal g-factors ranging from 0.9 to 22.4 and to depend on the electronic configuration of the devices. These results indicate strong Rashba spin-orbit interaction in our PbTe quantum dots.

3.
Retina ; 42(2): 274-282, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34483311

RESUMO

PURPOSE: To characterize the spectrum of internal limiting membrane (ILM) disease in Alport syndrome using multimodal imaging, including widefield (WF) and ultra-widefield (UWF) modalities, and to report their relative prevalence according to the genetic pattern of inheritance. METHODS: Cross-sectional clinical study of patients diagnosed with Alport syndrome. All patients underwent UWF color photography and autofluorescence, WF-optical coherence tomography angiography and spectral-domain optical coherence tomography. Demographics, past medical and ophthalmic history, and genetic mutation history were collected. RESULTS: Forty-two eyes of 21 patients (11 men; age 36.6 ± 12.9 years) were included. Macular spectral-domain optical coherence tomography revealed ILM granularity, more frequent in X-linked Alport syndrome and corresponding to dot maculopathy on color fundus. Mid-peripheral spectral-domain optical coherence tomography scans revealed multilamellated ILM in eight eyes (19%), presumably progressive, which corresponded to a cavitary pattern on en-face OCT. En-face OCT revealed multiple areas of retinal nerve fiber layer dehiscence in the macula, overlapping with vascular lacunae on optical coherence tomography angiography, and a coarse arrangement of retinal nerve fiber layer above and below the temporal raphe in 20 eyes (52%). CONCLUSION: Multimodal imaging allowed for the detection/characterization of retinal findings (ILM granularity, progressive ILM lamellation, retinal nerve fiber layer dehiscence, vascular lacunae, and coarse arrangement of retinal nerve fiber layer toward the disc) as multifaceted manifestations of ILM disease in Alport syndrome.


Assuntos
Membrana Basal/diagnóstico por imagem , Nefrite Hereditária/complicações , Fibras Nervosas/patologia , Doenças Retinianas/diagnóstico por imagem , Células Ganglionares da Retina/patologia , Adolescente , Adulto , Membrana Basal/patologia , Angiografia por Tomografia Computadorizada , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Tomografia de Coerência Óptica , Acuidade Visual/fisiologia , Adulto Jovem
4.
BMC Musculoskelet Disord ; 23(1): 133, 2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-35139829

RESUMO

BACKGROUND: The present study aimed to predict the expected number of patients with osteoarthritis (OA) in Austria up to the year 2080. METHODS: Demographic data and population projections between 2019 and 2080 were obtained from European authorities. Information about recent age- and sex-stratified prevalence of patients with self-reported physician-diagnosed OA was obtained from the Austrian Health Interview Survey (n = 15,771). Projections were stratified by age and sex; sensitivity analyses were performed based on aging, main (most likely), and growth scenarios of the population. RESULTS: Based on the projection, the overall increase in the total number of patients with OA from 2019 to 2080 will be 38% for men and women. In 2019, the highest number of OA-patients nested in the groups of persons aged 70-79 (n = 238,749) and 60-69 (n = 237,729) years. In 2080, the 80+ age group is predicted to have the highest number of OA with 421,548 individuals (i.e. factor 3.45 and factor 2.48 increase in the male and female group, respectively, compared to 2019), followed by the group aged 70-79 with 314,617 individuals (factor 1.45 and factor 1.28 increase in the male and female group, respectively, compared to 2019). Similar trends were found in the ageing and growing scenarios. CONCLUSIONS: The projected increase in the occurrence of OA will likely lead to a substantial socioeconomic burden for the Austrian healthcare system in the near and far future. The current findings plead for the development of sustainable concepts for the treatment and prevention of OA by European authorities.


Assuntos
Osteoartrite , Idoso , Áustria/epidemiologia , Europa (Continente)/epidemiologia , Feminino , Previsões , Humanos , Masculino , Osteoartrite/diagnóstico , Osteoartrite/epidemiologia , Osteoartrite/prevenção & controle , Prevalência
5.
BMC Musculoskelet Disord ; 23(1): 743, 2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35922780

RESUMO

BACKGROUND: Patients with ankylosing spondylitis (AS) have significantly lower quality of life (QoL) than the general population. Holistic interventions addressing QoL comprise spa- or balneotherapy including radon. These interventions have shown to be beneficial in reducing pain and improving QoL in AS-patients. We explored the association of spa-therapy including low-dose radon with QoL in AS-patients over an extended time period. METHODS: Registry data collected for the "Radon indication registry" in the Austrian Gastein valley comprising data on QoL (EuroQol EQ-5D) directly before the treatment (baseline), directly(t1), 3 (t2); 6(t3) and 9(t4) months after the treatment, age, sex and body mass index (BMI) were analysed. Linear regression models explored the association of measurement time with 1) EQ-5D-5L utilities and 2) EuroQol visual analogue scale (VAS) score. Alterations of 0.05 (utilities) and 5.00 (VAS) were considered clinically relevant. RESULTS: Two-hundred-ninety-one AS-patients were included in the analyses. Forty-four percent (n = 128) were women, the mean age was 52 (SD 10) and the average BMI was 26 (SD 4). Utilities (t1: 0.09 [0.07;0.11]; t2: 0.08 [0.06; 0.10]; t3: 0.06 [0.05;0.09]; t4: 0.04 [0.02;0.06]) and VAS (t1: 11.68 [9.38; 13.97]; t2: 12.20 [9.78; 14.61]; t3: 9.70 [7.24; 12.17]; t4: 6.11 [3.57; 8.65]) were significantly higher at all timepoints compared to baseline. Improvements were clinically relevant at all timepoints in case of the VAS and until 6 months after treatment for the utilities. CONCLUSION: AS-patients who received spa therapy including radon show significantly and clinically relevant improvements in Qol until 6-9 months after treatment.


Assuntos
Radônio , Espondilite Anquilosante , Feminino , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Qualidade de Vida , Radônio/uso terapêutico , Sistema de Registros , Espondilite Anquilosante/terapia , Inquéritos e Questionários
6.
Nano Lett ; 21(23): 9922-9929, 2021 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-34788993

RESUMO

Integration of high-quality semiconductor-superconductor devices into scalable and complementary metal-oxide-semiconductor compatible architectures remains an outstanding challenge, currently hindering their practical implementation. Here, we demonstrate growth of InAs nanowires monolithically integrated on Si inside lateral cavities containing superconducting TiN elements. This technique allows growth of hybrid devices characterized by sharp semiconductor-superconductor interfaces and with alignment along arbitrary crystallographic directions. Electrical characterization at low temperature reveals proximity induced superconductivity in InAs via a transparent interface.

7.
Neuroimage ; 238: 118240, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34116157

RESUMO

Retinotopy experiments using population receptive field (pRF) mapping are ideal for assigning regions in the visual field to cortical brain areas. While various designs for visual stimulation were suggested in the literature, all have specific shortcomings regarding visual field coverage. Here we acquired high-resolution 7 Tesla fMRI data to compare pRF-based coverage maps obtained with the two most commonly used stimulus variants: moving bars; rotating wedges and expanding rings. We find that stimulus selection biases the spatial distribution of pRF centres. In addition, eccentricity values and pRF sizes obtained from wedge/ring or bar stimulation runs show systematic differences. Wedge/ring stimulation results show lower eccentricity values and strongly reduced pRF sizes compared to bar stimulation runs. Statistical comparison shows significantly higher pRF centre numbers in the foveal 2° region of the visual field for wedge/ring compared to bar stimuli. We suggest and evaluate approaches for combining pRF data from different visual stimulus patterns to obtain improved mapping results.


Assuntos
Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos , Estimulação Luminosa/métodos , Retina/fisiologia , Córtex Visual/fisiologia , Campos Visuais/fisiologia , Adulto , Feminino , Humanos , Masculino , Vias Visuais/fisiologia , Adulto Jovem
8.
Int J Mol Sci ; 21(3)2020 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-31991850

RESUMO

Microglia are first-line defense antigen-presenting phagocytes in the central nervous system. Activated microglial cells release pro-inflammatory cytokines and can trigger an oxidative burst. The amino acid glycine exerts anti-inflammatory, immunomodulatory and cytoprotective effects and influences cell volume regulation. This study aimed to investigate the role of glycine in the modulation of inflammatory processes in mouse BV-2 microglial cells. Inflammatory stress was induced by lipopolysaccharide/interferon-γ (LPS/IFN-γ) treatment for 24 h in the absence or presence of 1 or 5 mM glycine. Cells were analyzed by flow cytometry for cell volume, side scatter, apoptosis/necrosis and expression of activation-specific surface markers. Apoptosis progression was monitored by life cell imaging. Reduced glutathione/oxidized glutathione (GSH/GSSG) ratios and release of the pro-inflammatory cytokines IL-6 and TNF-α were measured using luminescence-based assays and ELISA, respectively. We found that LPS/IFN-γ-induced apoptosis was decreased and the fraction of living cells was increased by glycine. Expression of the surface markers CD11b, CD54 and CD80 was dose-dependently increased, while IL-6 and TNF-α release was not altered compared to LPS/IFN-γ-treated cells. We showed that in BV-2 microglial cells glycine improves viability and counteracts deleterious responses to LPS/IFN-γ, which might be relevant in neurodegenerative processes associated with inflammation, like Alzheimer's or Parkinson's disease.


Assuntos
Apoptose/efeitos dos fármacos , Glicina/farmacocinética , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Microglia/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Antígenos CD/metabolismo , Linhagem Celular Transformada , Glutationa/metabolismo , Humanos , Interleucina-6/metabolismo , Camundongos , Microglia/patologia , Oxirredução/efeitos dos fármacos , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Fator de Necrose Tumoral alfa/metabolismo
9.
Cell Physiol Biochem ; 52(5): 951-969, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30977982

RESUMO

BACKGROUND/AIMS: Volume-regulated anion channels (VRACs) are of particular importance in regulating the cell volume (CV) and give rise to the swelling-activated Cl- current (ICl,swell), a main component driving global regulatory volume decrease (RVD) during cell swelling. Because ICl,swell affects numerous CV-regulated processes like migration, we assume that its role is also indispensable for phagocytosis which requires local cell swelling. Noradrenaline (NA) modulates phagocytosis in macrophages and microglial cells, macrophage-related cells in the central nervous system. Therefore we evaluated whether NA modulates ICl,swell and phagocytosis in microglia. METHODS: Experiments were performed in murine microglial BV-2 and primary mouse microglial cells. Patch clamp experiments were performed in BV-2 cells using the amphotericin-perforated method to minimize cytosolic disturbances. Phagocytosis was quantified by scanning electron microscopy. RESULTS: Following activation of ICl,swell by a hypotonic bath solution, noradrenaline, as well as the ß-adrenergic agonist isoproterenol, evoked a transient decrease of ICl,swell. Repeated application of adrenergic agonists caused a decline of this electrical response. Application of the agonist of exchange protein directly activated by cAMP (Epac), 8-pCPT-2-O-Me-cAMP, or the protein kinase A inhibitor H89 caused a persistent suppression of ICl,swell. When isoproterenol was added concomitantly with the hypotonic saline, ICl,swell developed more rapidly compared to control conditions. Uptake of IgG-coated beads was suppressed by NA or H89 when quantified after 15 min of exposure. CONCLUSION: The activation of ß-adrenergic receptors in microglial cells triggers a cAMP-Epac-dependent and a cAMP-PKA-dependent cascade which affects phagocytosis via modulation of the swelling-activated Cl- current ICl,swell.


Assuntos
Cloretos/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Microglia/metabolismo , Fagocitose , Sistemas do Segundo Mensageiro , Animais , Tamanho Celular , Células Cultivadas , AMP Cíclico/metabolismo , Transporte de Íons , Camundongos , Microglia/patologia
10.
Retina ; 39(3): 558-569, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29215532

RESUMO

PURPOSE: To examine the involvement of the retinal pigment epithelium (RPE) in the presence of vitelliform macular lesions (VML) in Best vitelliform macular dystrophy (BVMD), autosomal recessive bestrophinopathy, and adult-onset vitelliform macular degeneration using polarization-sensitive optical coherence tomography (PS-OCT). METHODS: A total of 35 eyes of 18 patients were imaged using a PS-OCT system and blue light fundus autofluorescence imaging. Pathogenic mutations in the BEST1 gene, 3 of which were new, were detected in all patients with BVMD and autosomal recessive bestrophinopathy. RESULTS: Polarization-sensitive optical coherence tomography showed a characteristic pattern in all three diseases with nondepolarizing material in the subretinal space consistent with the yellowish VML seen on funduscopy with a visible RPE line below it. A focal RPE thickening was seen in 26 eyes under or at the edge of the VML. Retinal pigment epithelium thickness outside the VML was normal or mildly thinned in patients with BVMD and adult-onset vitelliform macular degeneration but was diffusely thinned or atrophic in patients with autosomal recessive bestrophinopathy. Patients with autosomal recessive bestrophinopathy showed sub-RPE fibrosis alongside the subretinal VML. Polarization-sensitive optical coherence tomography was more reliable in assessing the localization and the integrity of the RPE than spectral domain OCT alone. On spectral domain OCT, identification of the RPE was not possible in 19.4% of eyes. Polarization-sensitive optical coherence tomography allowed for definite identification of the location of VML in respect to the RPE in all eyes, since it provides a tissue-specific contrast. CONCLUSION: Polarization-sensitive optical coherence tomography confirms in vivo the subretinal location of VML and is useful in the assessment of RPE integrity.


Assuntos
Distrofia Macular Viteliforme/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Angiofluoresceinografia/métodos , Humanos , Macula Lutea/patologia , Masculino , Pessoa de Meia-Idade , Epitélio Pigmentado da Retina/patologia , Tomografia de Coerência Óptica/métodos , Adulto Jovem
11.
BMC Musculoskelet Disord ; 20(1): 221, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-31096958

RESUMO

BACKGROUND: Non-specific chronic low back pain (nscLBP) has a high socio-economic relevance due to its high incidence, prevalence and associated costs. Therefore, it is essential to evaluate effective therapeutic strategies. This study examines the effects of moderate mountain exercise and spa therapy on orthopedic and psychophysiological parameters. Based on a three-armed randomized controlled trial, guided mountain hiking tours and balneotherapy in thermal water were compared to a control group. METHODS: Eighty patients with diagnosed nscLBP were separated into three groups: The two intervention groups GE (green exercise) and GEBT (green exercise and balneotherapy) undertook daily mountain hiking tours, whereas the GEBT group got an additional treatment with baths in Mg-Ca-SO4 thermal water. The third group (CO) received no intervention. GE and GEBT group were treated for 6 days; all groups were followed up for 120 days. RESULTS: Compared to GE and CO group, the GEBT treatment showed significant improvements of pain, some orthopedic parameters, health-related quality of life and mental well-being in patients with nscLBP. CONCLUSIONS: The results of this study confirmed a benefit of mountain hiking combined with Mg-Ca-SO4 spa therapy as a multimodal treatment of patients with nscLBP. Further studies should focus on long-term-effects of this therapeutic approach. TRIAL REGISTRATION: ISRCTN, ISRCTN99926592 . Registered 06. July 2018 - Retrospectively registered.


Assuntos
Balneologia/métodos , Exercício Físico , Dor Lombar/terapia , Águas Minerais/uso terapêutico , Adulto , Fatores Etários , Idoso , Terapia Combinada/métodos , Feminino , Temperatura Alta , Humanos , Dor Lombar/diagnóstico , Masculino , Pessoa de Meia-Idade , Medição da Dor , Qualidade de Vida , Fatores Sexuais , Resultado do Tratamento , Adulto Jovem
12.
Int J Mol Sci ; 20(14)2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31311135

RESUMO

Many cell types express an acid-sensitive outwardly rectifying (ASOR) anion current of an unknown function. We characterized such a current in BV-2 microglial cells and then studied its interrelation with the volume-sensitive outwardly rectifying (VSOR) Cl- current and the effect of acidosis on cell volume regulation. We used patch clamp, the Coulter method, and the pH-sensitive dye BCECF to measure Cl- currents and cell membrane potentials, mean cell volume, and intracellular pH, respectively. The ASOR current activated at pH ≤ 5.0 and displayed an I- > Cl- > gluconate- permeability sequence. When compared to the VSOR current, it was similarly sensitive to DIDS, but less sensitive to DCPIB, and insensitive to tamoxifen. Under acidic conditions, the ASOR current was the dominating Cl- conductance, while the VSOR current was apparently inactivated. Acidification caused cell swelling under isotonic conditions and prevented the regulatory volume decrease under hypotonicity. We conclude that acidification, associated with activation of the ASOR- and inactivation of the VSOR current, massively impairs cell volume homeostasis. ASOR current activation could affect microglial function under acidotoxic conditions, since acidosis is a hallmark of pathophysiological events like inflammation, stroke or ischemia and migration and phagocytosis in microglial cells are closely related to cell volume regulation.


Assuntos
Canais de Cloreto/metabolismo , Microglia/metabolismo , Potenciais de Ação , Animais , Linhagem Celular , Cloretos/metabolismo , Concentração de Íons de Hidrogênio , Iodo/metabolismo , Transporte de Íons , Camundongos , Microglia/fisiologia , Pressão Osmótica
13.
Cell Physiol Biochem ; 50(4): 1460-1473, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30359963

RESUMO

BACKGROUND/AIMS: The neutral, non-essential amino acid glycine has manifold functions and effects under physiological and pathophysiological conditions. Besides its function as a neurotransmitter in the central nervous system, glycine also exerts immunomodulatory effects and as an osmolyte it participates in cell volume regulation. During phagocytosis, glycine contributes to (local) cell volume-dependent processes like lamellipodium formation. Similar to the expansion of the lamellipodium we assume that glycine also affects the migration of microglial cells in a cell volume-dependent manner. METHODS: Mean cell volume (MCV) and cell migration were determined using flow cytometry and trans-well migration assays, respectively. Electrophysiological recordings of the cell membrane potential (Vmem) and swelling-dependent chloride (Cl-) currents (IClswell, VSOR, VRAC) were performed using the whole-cell patch clamp technique. RESULTS: In the murine microglial cell line BV-2, flow cytometry analysis revealed that glycine (5 mM) increases the MCV by ∼9%. The glycine-dependent increase in MCV was suppressed by the partial sodium-dependent neutral amino acid transporter (SNAT) antagonist MeAIB and augmented by the Cl- current blocker DCPIB. Electrophysiological recordings showed that addition of glycine activates a Cl- current under isotonic conditions resembling features of the swelling-activated Cl- current (IClswell). The cell membrane potential (Vmem) displayed a distinctive time course after glycine application; initially, glycine evoked a rapid depolarization mediated by Na+-coupled glycine uptake via SNAT, followed by a further gradual depolarization, which was fully suppressed by DCPIB. Interestingly, glycine significantly increased migration of BV-2 cells, which was suppressed by MeAIB, suggesting that SNAT is involved in the migration process of microglial cells. CONCLUSION: We conclude that glycine acts as a chemoattractant for microglial cells presumably by a cell volume-dependent mechanism involving SNAT-mediated cell swelling.


Assuntos
Sistema A de Transporte de Aminoácidos/metabolismo , Tamanho Celular/efeitos dos fármacos , Glicina/farmacologia , Sistema A de Transporte de Aminoácidos/antagonistas & inibidores , Animais , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Cloretos/metabolismo , Ciclopentanos/farmacologia , Soluções Hipotônicas/farmacologia , Indanos/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Microglia/citologia , Microglia/metabolismo , Nitrobenzoatos/farmacologia , Técnicas de Patch-Clamp
14.
Int J Mol Sci ; 19(3)2018 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-29510509

RESUMO

The clonogenic assay is a widely used method to study the ability of cells to 'infinitely' produce progeny and is, therefore, used as a tool in tumor biology to measure tumor-initiating capacity and stem cell status. However, the standard protocol of using 6-well plates has several disadvantages. By miniaturizing the assay to a 96-well microplate format, as well as by utilizing the confluence detection function of a multimode reader, we here describe a new and modified protocol that allows comprehensive experimental setups and a non-endpoint, label-free semi-automatic analysis. Comparison of bright field images with confluence images demonstrated robust and reproducible detection of clones by the confluence detection function. Moreover, time-resolved non-endpoint confluence measurement of the same well showed that semi-automatic analysis was suitable for determining the mean size and colony number. By treating cells with an inhibitor of clonogenic growth (PTC-209), we show that our modified protocol is suitable for comprehensive (broad concentration range, addition of technical replicates) concentration- and time-resolved analysis of the effect of substances or treatments on clonogenic growth. In summary, this protocol represents a time- and cost-effective alternative to the commonly used 6-well protocol (with endpoint staining) and also provides additional information about the kinetics of clonogenic growth.


Assuntos
Miniaturização/métodos , Ensaio Tumoral de Célula-Tronco/métodos , Linhagem Celular Tumoral , Citostáticos/toxicidade , Compostos Heterocíclicos com 2 Anéis/toxicidade , Humanos , Tiazóis/toxicidade
15.
Cell Physiol Biochem ; 41(3): 1011-1019, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28291963

RESUMO

BACKGROUND/AIMS: For in vitro cytotoxicity testing, discrimination of apoptosis and necrosis represents valuable information. Viability analysis performed at two different time points post treatment could serve such a purpose because the dynamics of metabolic activity of apoptotic and necrotic cells is different, i.e. a more rapid decline of cellular metabolism during necrosis whereas cellular metabolism is maintained during the entire execution phase of apoptosis. This study describes a straightforward approach to distinguish apoptosis and necrosis. METHODS: A431 human epidermoid carcinoma cells were treated with different concentrations/doses of actinomycin D (Act-D), 4,5,6,7-tetrabromo-2-azabenzimidazole (TBB), Ro 31-8220, H2O2 and photodynamic treatment (PDT). The resazurin viability signal was recorded at 2 and 24 hrs post treatment. Apoptosis and necrosis were verified by measuring caspase 3/7 and membrane integrity. RESULTS: Calculation of the difference curve between the 2 and 24 hrs resazurin signals yields the following information: a positive difference signal indicates apoptosis (i.e. high metabolic activity at early time points and low signal at 24 hrs post treatment) while an early reduction of the viability signal indicates necrosis. For all treatments, this dose-dependent sequence of cellular responses could be confirmed by independent assays. CONCLUSION: Simple and cost-effective viability analysis provides reliable information about the dose ranges of a cytotoxic agent where apoptosis or necrosis occurs. This may serve as a starting point for further in-depth characterisation of cytotoxic treatments.


Assuntos
Apoptose/efeitos dos fármacos , Bioensaio , Indicadores e Reagentes/química , Necrose/induzido quimicamente , Oxazinas/química , Xantenos/química , Biomarcadores/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Caspase 7/genética , Caspase 7/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dactinomicina/farmacologia , Relação Dose-Resposta a Droga , Epiderme , Expressão Gênica , Humanos , Peróxido de Hidrogênio/farmacologia , Indóis/farmacologia , Luz , Necrose/metabolismo , Necrose/patologia , Triazóis/farmacologia
16.
Cell Physiol Biochem ; 43(3): 1037-1051, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28968600

RESUMO

BACKGROUND/AIMS: Glucose-stimulated insulin secretion (GSIS) of pancreatic ß-cells involves glucose uptake and metabolism, closure of KATP channels and depolarization of the cell membrane potential (Vmem), activation of voltage-activated Ca2+ currents (ICav) and influx of Ca2+, which eventually triggers hormone exocytosis. Beside this classical pathway, KATP-independent mechanisms such as changes in intracellular pH (pHi) or cell volume, which also affect ß-cell viability, can elicit or modify insulin release. In ß-cells the regulation of pHi is mainly accomplished by Na+/H+ exchangers (NHEs). To investigate if other proton extrusion mechanisms than NHEs are involved in pH regulation, we tested for the presence of the non-gastric H+/K+ ATPase in rat insulinoma cells and assessed effects of the H+/K+ ATPase inhibitor SCH-28080 on insulin secretion, cell viability and apoptosis. METHODS: In INS-1E cell cultures, H+/K+ ATPase gene and protein expression was analyzed by reverse transcription PCR and Western blotting. Intracellular pH (pHi) recovery after acute acidic load was measured by NH4Cl prepulsing using BCECF. Insulin secretion was determined by ELISA from the cell culture supernatant. Vmem, K+ and Ca2+ currents were recorded using patch clamp. Overall cell responses were determined using resazurin (viability) and cytotoxicity assays. The mean cell volume (MCV), cell granularity (side-scatter; SSC), phosphatidylserine (PS) exposure, cell membrane integrity, caspase activity and the mitochondrial membrane potential (ΔΨm) were measured by flow cytometry. RESULTS: We found that the α-subunit of the non-gastric H+/K+ ATPase (HKα2) is expressed on mRNA and protein level. However, compared to rat colon tissue, in INS-1E cells mRNA abundance was very low. In NH4Cl prepulsing experiments no K+-dependent pHi recovery was observed under Na+-free extracellular conditions. Nonetheless within 1 h, 20 µM SCH-28080 inhibited GSIS by ∼50%, while basal release was unaffected. The L-type ICav blocker nifedipine caused a full inhibition of GSIS at 10 and 20 µM. At 20 µM, SCH-28080 inhibited ICav comparable to 20 µM nifedipine and in addition augmented IKATP recorded at -60 mV and hyperpolarized Vmem by ∼15 mV. Cell viability 2 and 24 h post treatment with SCH-28080 was dose-dependently inhibited with IC50 values of 22.9 µM and 15.3 µM, respectively. At 20 µM the percentages of Annexin-V+, caspase+ and propidium iodide+ cells were significantly increased after 24 and 48 h. Concurrently, the MCV was significantly decreased (apoptotic volume decrease, AVD) and the SSC signal was increased. At concentrations >40-50 µM, SCH-28080 became progressively cytotoxic causing a steep increase in necrotic cells already 2 h post treatment and a breakdown of ΔΨm within 4 h under 50 and 100 µM while 10 and 20 µM had no effect on ΔΨm within 24 h. CONCLUSION: We demonstrate expression of HKα2 in rat INS-1E cells. However, the pump is apparently non-functional under the given conditions. Nonetheless the H+/K+ ATPase blocker SCH-28080 inhibits insulin secretion and induces cell death. Importantly, we show that SCH-28080 inhibits ICav - and activates KATP channels identifying them as novel "off-targets" of the inhibitor, causing hyperpolarization of Vmem and inhibition of insulin secretion.


Assuntos
Apoptose/efeitos dos fármacos , ATPase Trocadora de Hidrogênio-Potássio/metabolismo , Imidazóis/toxicidade , Insulina/análise , Inibidores da Bomba de Prótons/toxicidade , Animais , Cálcio/metabolismo , Linhagem Celular Tumoral , Tamanho Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Colo/metabolismo , Ensaio de Imunoadsorção Enzimática , Glucose/farmacologia , ATPase Trocadora de Hidrogênio-Potássio/química , ATPase Trocadora de Hidrogênio-Potássio/genética , Concentração de Íons de Hidrogênio , Insulina/metabolismo , Secreção de Insulina , Insulinoma/metabolismo , Insulinoma/patologia , Canais KATP/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Nifedipino/toxicidade , Técnicas de Patch-Clamp , Fosfatidilserinas/farmacologia , RNA Mensageiro/metabolismo , Ratos
17.
Cell Physiol Biochem ; 39(1): 278-93, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27336168

RESUMO

BACKGROUND/AIMS: Previously we described insulinotropic effects of Leonurus sibiricus L. plant extracts used for diabetes mellitus treatment in Traditional Mongolian Medicine. The flavonoid quercetin and its glycoside rutin, which exert anti-diabetic properties in vivo by interfering with insulin signaling in peripheral target tissues, are constituents of these extracts. This study was performed to better understand short- and long-term effects of quercetin and rutin on beta-cells. METHODS: Cell viability, apoptosis, phospho-protein abundance and insulin release were determined using resazurin, annexin-V binding assays, Western blot and ELISA, respectively. Membrane potentials (Vmem), whole-cell Ca2+ (ICa)- and ATP-sensitive K+ (IKATP) currents were measured by patch clamp. Intracellular Ca2+ (Cai) levels were measured by time-lapse imaging using the ratiometric Ca2+ indicator Fura-2. RESULTS: Rutin, quercetin and the phosphoinositide-3-kinase (PI3K) inhibitor LY294002 caused a dose-dependent reduction in cell viability with IC50 values of ∼75 µM, ∼25 µM and ∼3.5 µM, respectively. Quercetin (50 µM) significantly increased the percentage of Annexin-V+ cells within 48 hrs. The mean cell volume (MCV) of quercetin-treated cells was significantly lower. Within 2 hrs, quercetin significantly decreased basal- and insulin-stimulated Akt(T308) phosphorylation and increased Erk1/2 phosphorylation, without affecting P-Akt(S473) abundance. Basal- and glucose-stimulated insulin release were significantly stimulated by quercetin. Quercetin significantly depolarized Vmem by ∼25 mV which was prevented by the KATP-channel opener diazoxide, but not by the L-type ICa inhibitor nifedipine. Quercetin significantly stimulated ICa and caused a 50% inhibition of IKATP. The effects on Vmem, ICa and IKATP rapidly reached peak values and then gradually diminished to control values within ∼1 minute. With a similar time-response quercetin induced an elevation in Cai which was completely abolished in the absence of Ca2+ in the bath solution. Rutin (50 µM) did not significantly alter the percentage of Annexin-V+ cells, MCV, Akt or Erk1/2 phosphorylation, insulin secretion, or the electrophysiological behavior of INS-1 cells. CONCLUSION: We conclude that quercetin acutely stimulates insulin release, presumably by transient KATP channel inhibition and ICa stimulation. Long term application of quercetin inhibits cell proliferation and induces apoptosis, most likely by inhibition of PI3K/Akt signaling.


Assuntos
Células Secretoras de Insulina/efeitos dos fármacos , Insulina/metabolismo , Quercetina/farmacologia , Rutina/farmacologia , Animais , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Western Blotting , Cálcio/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Citometria de Fluxo , Glucose/farmacologia , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/fisiologia , Potenciais da Membrana/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação/efeitos dos fármacos , Extratos Vegetais/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos
18.
Int J Mol Sci ; 17(12)2016 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-27941621

RESUMO

Extensive stromal interaction is one reason for the dismal outcome of biliary tract cancer (BTC) patients. Epithelial to mesenchymal transition (EMT) is involved in tumor invasion and metastasis and is partly regulated by microRNAs (miRs). This study explores the expression of anti-EMT miR200 family (miR141, -200a/b/c, -429) and miR205 as well as the EMT-related proteins E-cadherin and vimentin in a panel of BTC cell lines and clinical specimens by quantitative real-time polymerase chain reaction, Western blot and immunohistochemistry, respectively. MicroRNA expression was correlated to (i) the expression patterns of E-cadherin and vimentin; (ii) clinicopathological characteristics; and (iii) survival data. MicroRNA-200 family and miR205 were expressed in all BTC cells and clinical specimens. E-cadherin and vimentin showed a mutually exclusive expression pattern in both, in vitro and in vivo. Expression of miR200 family members positively correlated with E-cadherin and negatively with vimentin expression in BTC cells and specimens. High expression of miR200 family members (but not miR205) and E-cadherin was associated with longer survival, while low miR200 family and high vimentin expression was a predictor of unfavorable survival. Overall, the current study demonstrates the relevance of the miR200 family in EMT of BTC tumors and suggests these miRs as predictors for positive outcome.


Assuntos
Neoplasias do Sistema Biliar/genética , Neoplasias do Sistema Biliar/patologia , Transição Epitelial-Mesenquimal/genética , MicroRNAs/genética , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/fisiologia , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , RNA Mensageiro/genética
19.
Radiat Environ Biophys ; 54(1): 123-136, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25274266

RESUMO

Low-dose radon hyperthermia balneo treatment (LDRnHBT) is applied as a traditional measure in the non-pharmacological treatment of rheumatic diseases in Europe. During the last decades, the main approach of LDRnHBT was focused on the treatment of musculoskeletal disorders, but scientific evidence for the biological background of LDRnHBT is weak. Recently, evidence emerged that LDRnHBT influences bone metabolism. We investigated, whether combined LDRnHBT and exercise treatment has an impact on bone metabolism and quality of life in a study population in an age group at risk for developing osteoporosis. This randomized, double-blind, placebo-controlled trial comprised guided hiking tours and hyperthermia treatment in either radon thermal water (LDRnHBT) or radon-free thermal water (PlaceboHBT). Markers of bone metabolism, quality of life and somatic complaints were evaluated. Statistics was performed by linear regression and a linear mixed model analysis. Significant changes over time were observed for most analytes investigated as well as an improvement in self-assessed health in both groups. No significant impact from the LDRnHBT could be observed. After 6 months, the LDRnHBT group showed a slightly stronger reduction of the osteoclast stimulating protein receptor activator of nuclear kB-ligand compared to the PlaceboHBT group, indicating a possible trend. A combined hyperthermia balneo and exercise treatment has significant immediate and long-term effects on regulators of bone metabolism as well as somatic complaints. LDRnHBT and placeboHBT yielded statistically equal outcomes.


Assuntos
Balneologia , Terapia por Exercício , Osteoporose/radioterapia , Osteoporose/terapia , Radônio/uso terapêutico , Hormônio Adrenocorticotrópico/sangue , Reabsorção Óssea , Osso e Ossos/metabolismo , Método Duplo-Cego , Feminino , Humanos , Leptina/sangue , Masculino , Pessoa de Meia-Idade , Osteocalcina/sangue , Osteogênese/efeitos dos fármacos , Osteoporose/sangue , Osteoprotegerina/sangue , Hormônio Paratireóideo/sangue , Qualidade de Vida , Ligante RANK/sangue
20.
Cell Physiol Biochem ; 34(5): 1507-26, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25322912

RESUMO

BACKGROUND/AIMS: The ATP12A gene codes for a non-gastric H(+)/K(+) ATPase, which is expressed in a wide variety of tissues. The aim of this study was to test for the molecular and functional expression of the non-gastric H(+)/K(+) ATPase ATP12A/ATP1AL1 in unstimulated and butyrate-stimulated (1 and 10 mM) human myelomonocytic HL-60 cells, to unravel its potential role as putative apoptosis-counteracting ion transporter as well as to test for the effect of the H(+)/K(+) ATPase inhibitor SCH28080 in apoptosis. METHODS: Real-time reverse-transcription PCR (qRT-PCR) was used for amplification and cloning of ATP12A transcripts and to assess transcriptional regulation. BCECF microfluorimetry was used to assess changes of intracellular pH (pHi) after acute intracellular acid load (NH4Cl prepulsing). Mean cell volumes (MCV) and MCV-recovery after osmotic cell shrinkage (Regulatory Volume Increase, RVI) were assessed by Coulter counting. Flow-cytometry was used to measure MCV (Coulter principle), to assess apoptosis (phosphatidylserine exposure to the outer leaflet of the cell membrane, caspase activity, 7AAD staining) and differentiation (CD86 expression). RESULTS: We found by RT-PCR, intracellular pH measurements, MCV measurements and flow cytometry that ATP12A is expressed in human myelomonocytic HL-60 cells. Treatment of HL-60 cells with 1 mM butyrate leads to monocyte-directed differentiation whereas higher concentrations (10 mM) induce apoptosis as assessed by flow-cytometric determination of CD86 expression, caspase activity, phosphatidylserine exposure on the outer leaflet of the cell membrane and MCV measurements. Transcriptional up-regulation of ATP12A and CD86 is evident in 1 mM butyrate-treated HL-60 cells. The H(+)/K(+) ATPase inhibitor SCH28080 (100 µM) diminishes K(+)-dependent pHi recovery after intracellular acid load and blocks RVI after osmotic cell shrinkage. After seeding, HL-60 cells increase their MCV within the first 24 h in culture, and subsequently decrease it over the course of the next 48 h. This effect can be observed in the overall- and non-apoptotic fraction of both untreated and 1 mM butyrate-treated HL-60 cells, but not in 1 mM butyrate-stimulated phosphatidylserine-positive cells. These cells do not shrink from 24 h to 72 h and have finally a higher MCV than untreated cells unless they are exposed to SCH28080. 10 mM butyrate induces apoptosis within 24 h. CONCLUSION: In summary we show that in HL-60 cells ATP12A is a functionally active H(+)/K(+) ATPase that may counteract events during early apoptosis like intracellular acidosis, loss of intracellular K(+) ions and apoptotic volume decrease. Its expression and/or susceptibility to the H(+)/K(+) ATPase inhibitor SCH28080 becomes most evident in cells exposing phosphatidylserine on the outer leaflet of the cell membrane and therefore during early apoptosis.


Assuntos
Apoptose/efeitos dos fármacos , Butiratos/farmacologia , ATPase Trocadora de Hidrogênio-Potássio/metabolismo , Imidazóis/farmacologia , Transporte de Íons/efeitos dos fármacos , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Células HL-60 , Humanos
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