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1.
BMC Health Serv Res ; 24(1): 314, 2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38459522

ABSTRACT

BACKGROUND: Clinical empathy is considered a crucial element in patient-centered care. The advent of digital technology in healthcare has introduced new dynamics to empathy which needs to be explored in the context of the technology, particularly within the context of written live chats. Given the growing prevalence of written live chats, this study aimed to explore and evaluate techniques of digital clinical empathy within a familial cancer-focused live chat, focusing on how health professionals can (a) understand, (b) communicate, and (c) act upon users' perspectives and emotional states. METHODS: The study utilized a qualitative approach in two research phases. It examined the expected and implemented techniques and effectiveness of digital clinical empathy in a live chat service, involving semi-structured interviews with health professionals (n = 9), focus group discussions with potential users (n = 42), and two rounds of usability tests between health professionals (n = 9) and users (n = 18). Data were examined using qualitative content analysis. RESULTS: Expected techniques of digital clinical empathy, as articulated by both users and health professionals, involve reciprocal engagement, timely responses, genuine authenticity, and a balance between professionalism and informality, all while going beyond immediate queries to facilitate informed decision-making. Usability tests confirm these complexities and introduce new challenges, such as balancing timely, authentic responses with effective, personalized information management and carefully framed referrals. CONCLUSIONS: The study reveals that the digital realm adds layers of complexity to the practice of clinical empathy. It underscores the importance of ongoing adaptation and suggests that future developments could benefit from a hybrid model that integrates the strengths of both AI and human health professionals to meet evolving user needs and maintain high-quality, empathetic healthcare interactions.


Subject(s)
Delivery of Health Care , Empathy , Humans , Qualitative Research , Health Personnel/psychology , Focus Groups
2.
ACS Appl Bio Mater ; 6(8): 3089-3102, 2023 08 21.
Article in English | MEDLINE | ID: mdl-37433114

ABSTRACT

Mesoporous and nonmesoporous SiO2@MnFe2O4 nanostructures were loaded with the hypoxia-inducible factor-1 inhibitor acriflavine for combined radiation and hypoxia therapies. The X-ray irradiation of the drug-loaded nanostructures not only triggered the release of the acriflavine inside the cells but also initiated an energy transfer from the nanostructures to surface-adsorbed oxygen to generate singlet oxygen. While the drug-loaded mesoporous nanostructures showed an initial drug release before the irradiation, the drug was primarily released upon X-ray radiation in the case of the nonmesoporous nanostructures. However, the drug loading capacity was less efficient for the nonmesoporous nanostructures. Both drug-loaded nanostructures proved to be very efficient in irradiated MCF-7 multicellular tumor spheroids. The damage of these nanostructures toward the nontumorigenic MCF-10A multicellular spheroids was very limited because of the small number of nanostructures that entered the MCF-10A spheroids, while similar concentrations of acriflavine without nanostructures were toxic for the MCF-10A spheroids.


Subject(s)
Acriflavine , Nanostructures , Humans , Acriflavine/therapeutic use , Hypoxia/drug therapy , Nanostructures/therapeutic use , Silicon Dioxide/chemistry
3.
Pflege ; 36(1): 56-63, 2023 Feb.
Article in German | MEDLINE | ID: mdl-36426563

ABSTRACT

Nursing experts in primary care of chronically ill persons: Insights into an ongoing project Abstract. Background: The project HandinHand develops and tries out a new interprofessional form of care for chronically ill persons. On referral by the attending doctors, nursing experts visit chronically ill persons older than 60 years on a regular basis. In this framework a clinical supervision takes place and is complemented by a promotion of health and self-management competencies of the patients. According to advanced nursing practice, nursing experts function as consultants and instructors for the target group and their relatives. Methods: This paper describes the field of action and the vocational role of nursing experts. Following the delegation agreement and the development of the project, opportunities and boundaries of this new form of care are discussed. Results: The project HandinHand introduces a new role for nursing experts in the German health care system. Conclusion: This form of cooperation between doctors and nursing experts is a model of good practice. It can be seen as a starting point for the development of new fields of action and roles of advanced nursing practice for academically educated nurses.


Subject(s)
Advanced Practice Nursing , Delivery of Health Care , Humans , Primary Health Care , Chronic Disease , Longitudinal Studies
4.
Nanomaterials (Basel) ; 11(5)2021 Apr 29.
Article in English | MEDLINE | ID: mdl-33947086

ABSTRACT

Au-Fe3O4 nanoheterodimers (NHD) were functionalized with the natural and synthetic anticancer drugs caffeic acid (CA), quercetin (Q) and 5-fluorocytidine (5FC). Their X-radiation dose-enhancing potential and chemotherapeutic efficacy for bimodal cancer therapy were investigated by designing multicellular tumor spheroids (MCTS) to in vitro avascular tumor models. MCTS were grown from the breast cancer cell lines MCF-7, MDA-MB-231, and MCF-10A. The MCF-7, MDA-MB-231 and MCF-10A MCTS were incubated with NHD-CA, NHD-Q, or NHD-5FC and then exposed to fractionated X-radiation comprising either a single 10 Gy dose, 2 daily single 5 Gy doses or 5 daily single 2 Gy doses. The NHD-CA, NHD-Q, and NHD-5FC affected the growth of X-ray irradiated and non-irradiated MCTS in a different manner. The impact of the NHDs on the glycolytic metabolism due to oxygen deprivation inside MCTS was assessed by measuring lactate secretion and glucose uptake by the MCTS. The NHD-CA and NHD-Q were found to act as X-radiation dose agents in MCF-7 MCTS and MDA-MB-231 MCTS and served as radioprotector in MCF-10A MCTS. X-ray triggered release of CA and Q inhibited lactate secretion and thereupon disturbed glycolytic reprogramming, whereas 5FC exerted their cytotoxic effects on both, healthy and tumor cells, after their release into the cytosol.

5.
Chemistry ; 27(5): 1655-1669, 2021 Jan 21.
Article in English | MEDLINE | ID: mdl-33459437

ABSTRACT

A new series of shell-by-shell (SbS)-functionalized Al2 O3 nanoparticles (NPs) containing a perylene core in the organic interlayer as a fluorescence marker is introduced. Initially, the NPs were functionalized with both, a fluorescent perylene phosphonic acid derivative, together with the lipophilic hexadecylphosphonic acid or the fluorophilic (1 H,1 H,2 H,2H-perfluorodecyl)phosphonic acid. The lipophilic first-shell functionalized NPs were further implemented with amphiphiles built of aliphatic chains and polar head-groups. However, the fluorophilic NPs were combined with amphiphiles consisting of fluorocarbon tails and polar head-groups. Depending on the nature of the combined phosphonic acids and the amphiphiles, tuning of the perylene fluorescence can be accomplished due variations of supramolecular organization with the shell interface. Because the SbS-functionalized NPs dispose excellent dispersibility in water and in biological media, two sorts of NPs with different surface properties were tested with respect to biological fluorescent imaging applications. Depending on the agglomeration of the NPs, the cellular uptake differs. The uptake of larger agglomerates is facilitated by endocytosis, whereas individualized NPs cross directly the cellular membrane. Also, the larger agglomerates were preferentially incorporated by all tested cells.

6.
ACS Appl Bio Mater ; 4(11): 7879-7892, 2021 11 15.
Article in English | MEDLINE | ID: mdl-35006769

ABSTRACT

The X-radiation enhancing effect of caffeic acid-functionalized Au-Fe3O4, Pt-Fe3O4, and Pd-Fe3O4 nanoheterodimers (NHDs) on 2D and 3D breast tumor (MCF-7) and healthy breast epithelial (MCF-10A) cells was comprehensively examined by performing cell viability, reactive oxygen species (ROS) detection, enzyme activity, and clonogenic assays. Intracellular NHDs were observed to cause DNA fragmentation and to enhance superoxide and hydroxyl radical formation in MCF-7 cells when exposed to a single dose of 1 Gy. MCF-7-derived multicellular tumor spheroids (MCF-7 MCTS) and MCF-10A-derived multicellular spheroids (MCF-10A MCS) were incubated with the NHDs and irradiated with five daily doses of 2 Gy. The Au-Fe3O4 and Pt-Fe3O4 NHD-loaded MCF-7 MCTS significantly decreased in volume after being exposed to fractionated irradiation, whereas intracellular Au-Fe3O4 and Pt-Fe3O4 NHDs promoted the growth of the irradiated MCF-10A MCS. Moreover, Au-Fe3O4 and Pt-Fe3O4 NHDs were shown to impede ROS formation and inhibit DNA strand breakage in the noncancerous MCF-10A cells. On the other hand, the Pd-Fe3O4 NHDs boosted X-radiation-induced damage of MCF-10 A cells, which was ascribed to impairment of the ROS scavenging enzyme activities. In summary, caffeic acid-functionalized Au-Fe3O4 and Pt-Fe3O4 NHDs performed as excellent X-radiation enhancing agents in breast tumor cells, while they protect healthy breast epithelial cells against X-radiation.


Subject(s)
Breast Neoplasms , Radiation-Sensitizing Agents , Breast/pathology , Breast Neoplasms/drug therapy , Female , Humans , Iron , MCF-7 Cells , Radiation-Sensitizing Agents/pharmacology , Reactive Oxygen Species
7.
ACS Appl Bio Mater ; 4(4): 3113-3123, 2021 04 19.
Article in English | MEDLINE | ID: mdl-35014399

ABSTRACT

The efficiency of nanoparticle-enhanced radiotherapy was studied by loading MCF-7 and A549 multicellular tumor spheroids (MCTSs) with caffeic acid- and nitrosonium-functionalized Au-Fe3O4 nanoheterodimers (Au-Fe3O4 NHDs). Transmission electron microscope images of MCTS cross-sectional sections visualized the invasion and distribution of the nitrosonium- and caffeic acid-functionalized Au-Fe3O4 NHDs (NO- and CA-NHDs) in the A549 and MCF-7 MCTSs, whereas the iron content of the MCTSs were quantified using the ferrozine assay. The synergistic impact of intracellular NO- and CA-NHDs and X-ray irradiation on the growth dynamics of the A549 and MCF-7 MCTSs was surveyed by monitoring their temporal evolution under a light microscope over a period of 14 days. The emergence of hypoxia during the spheroid growth was followed by detecting the lactate efflux of MCTSs without and with NO- and CA-NHDs. The performance of the NO- and CA-NHDs as X-ray dose-enhancing agents in the A549 and MCF-7 MCTSs was clarified by performing clonogenic cell survival assays and determining the respective dose-modifying factors for X-ray doses of 0, 2, 4, and 6 Gy. The NO- and CA-NHDs were shown to perform as potent X-ray dose-enhancing agents in A549 and MCF-7 MCTSs. Moreover, the CA-NHDs boosted their radio-sensitizing efficacy by inhibiting the lactate efflux as impairing metabolic reprogramming. A synergistic effect on the MCTS destruction was observed for the combination of both NHDs since the surfactants differ in their antitumor effect.


Subject(s)
Biocompatible Materials/pharmacology , Ferric Compounds/pharmacology , Gold/pharmacology , Nanoparticles/chemistry , Spheroids, Cellular/drug effects , X-Rays , Biocompatible Materials/chemistry , Cell Survival/drug effects , Ferric Compounds/chemistry , Gold/chemistry , Humans , MCF-7 Cells , Materials Testing , Particle Size
8.
Bioengineering (Basel) ; 7(4)2020 Oct 12.
Article in English | MEDLINE | ID: mdl-33053776

ABSTRACT

Our research objective was to develop novel drug delivery vehicles consisting of TiO2 and Al2O3 nanoparticles encapsulated by a bilayer shell that allows the reversible embedment of hydrophobic drugs. The first shell is formed by covalent binding of hydrophobic phosphonic acid at the metal oxide surface. The second shell composed of amphiphilic sodium dodecylbenzenesulfonate emerges by self-aggregation driven by hydrophobic interactions between the dodecylbenzene moiety and the hydrophobic first shell. The resulting double layer provides hydrophobic pockets suited for the intake of hydrophobic drugs. The nanoparticles were loaded with the anticancer drugs quercetin and 7-amino-4-methylcoumarin. Irradiation with X-rays was observed to release the potential anticancer drugs into the cytoplasm. In Michigan Cancer Foundation (MCF)-10 A cells, quercetin and 7-amino-4-methylcoumarin acted as antioxidants by protecting the non-tumorigenic cells from harmful radiation effects. In contrast, these agents increased the reactive oxygen species (ROS) formation in cancerous MCF-7 cells. Quercetin and 7-amino-4-methylcoumarin were shown to induce apoptosis via the mitochondrial pathway in cancer cells by determining an increase in TUNEL-positive cells and a decrease in mitochondrial membrane potential after irradiation. After X-ray irradiation, the survival fraction of MCF-7 cells with drug-loaded nanoparticles considerably decreased, which demonstrates the excellent performance of the double-layer stabilized nanoparticles as drug delivery vehicles.

9.
ACS Appl Mater Interfaces ; 11(43): 39613-39623, 2019 Oct 30.
Article in English | MEDLINE | ID: mdl-31613607

ABSTRACT

Bifunctional Au-Fe3O4 nanoheterodimers were synthesized by thermally decomposing Fe(III)oleate on gold nanoparticles followed by functionalizing with tiron, 2,3-dihydroxybenzoic acid, or caffeic acid. These catechol derivatives are antioxidative and thus are predicted to function as superoxide scavengers. In particular, caffeic acid lost its antioxidant capacity, although it was covalently linked through its carboxyl moiety to the Fe3O4 surface. Tiron was shown to bind via its catechol group to the Au-Fe3O4 nanoheterodimers, and 2,3-dihydroxybenzoic was just physisorbed between the oleic acid surface structures. Caffeic-acid stabilized Au-Fe3O4 nanoheterodimers turned out to act as X-ray protector in healthy cells but as X-ray enhancing agents in cancer cells. Furthermore, these functionalized Au-Fe3O4 nanoheterodimers were found to inhibit the migratory capacity of the cancer cells.


Subject(s)
Caffeic Acids , Ferrosoferric Oxide , Free Radical Scavengers , Gold , Nanostructures , Neoplasms , Radiation-Protective Agents , Caffeic Acids/chemistry , Caffeic Acids/pharmacology , Ferrosoferric Oxide/chemistry , Ferrosoferric Oxide/pharmacology , Free Radical Scavengers/chemistry , Free Radical Scavengers/pharmacology , Gold/chemistry , Gold/pharmacology , Humans , MCF-7 Cells , Nanostructures/chemistry , Nanostructures/therapeutic use , Neoplasms/metabolism , Neoplasms/pathology , Neoplasms/radiotherapy , Radiation-Protective Agents/chemistry , Radiation-Protective Agents/pharmacology , X-Rays
10.
ACS Appl Mater Interfaces ; 10(20): 17071-17080, 2018 May 23.
Article in English | MEDLINE | ID: mdl-29738226

ABSTRACT

Snowman-shaped Au-Fe3O4 nanoheterodimers were synthesized by thermal decomposition of iron oleate on presynthesized Au nanoparticles. Subsequently performed ligand exchange with nitrosyl tetrafluoroborate provided water solubility and enabled X-ray-induced NO release. These Au-Fe3O4 nanoheterodimers combine high- Z material with catalytically active Fe3O4 surfaces and, moreover, plasmonic properties with superparamagnetic performance. We could establish synergetic interactions between X-radiation and both the Au and Fe3O4 surfaces, which resulted in the simultaneous production of the nitric oxide radical at the Fe3O4 surface and the superoxide radical at the Au surface. The surface-confined reaction between these radicals generated peroxynitrite. This highly reactive species may cause nitration of mitochondrial proteins and lipid peroxidation and induce DNA strand breaks. Therefore, high concentrations of peroxynitrite are expected to give rise to severe cellular energetic derangements and thereupon entail rapid cell death. As providing a common platform for X-ray-induced formation of the highly reactive radical nitric oxide, superoxide, and peroxynitrite, nitrosyl tetrafluoroborate functionalized Au-Fe3O4 nanosnowmen were shown to exhibit excellent performance as X-ray-enhancing agents in radiation therapy.


Subject(s)
Borates/chemistry , Nitric Oxide/chemistry , Ferrous Compounds , Nanoparticles , Reactive Oxygen Species , Superoxides
11.
Small ; 14(21): e1704111, 2018 05.
Article in English | MEDLINE | ID: mdl-29667293

ABSTRACT

Efficient magnetic reactive oxygen species (ROS) formation enhancing agents after X-ray treatment are realized by functionalizing superparamagnetic magnetite (Fe3 O4 ) and Co-ferrite (CoFe2 O4 ) nanoparticles with self-assembled monolayers (SAMs). The Fe3 O4 and CoFe2 O4 nanoparticles are synthesized using Massart's coprecipitation technique. Successful surface modification with the SAM forming compounds 1-methyl-3-(dodecylphosphonic acid) imidazolium bromide, or (2-{2-[2-hydroxy-ethoxy]-ethoxy}-ethyl phosphonic acid provides biocompatibility and long-term stability of the Fe3 O4 and CoFe2 O4 nanoparticles in cell media. The SAM-stabilized ferrite nanoparticles are characterized with dynamic light scattering, X-ray powder diffraction, a superconducting quantum interference device, Fourier transform infrared attenuated total reflectance spectroscopy, zeta potential measurements, and thermogravimetric analysis. The impact of the SAM-stabilized nanoparticles on the viability of the MCF-7 cells and healthy human umbilical vein endothelial cells (HUVECs) is assessed using the neutral red assay. Under X-ray exposure with a single dosage of 1 Gy the intracellular SAM stabilized Fe3 O4 and CoFe2 O4 nanoparticles are observed to increase the level of ROS in MCF-7 breast cancer cells but not in healthy HUVECs. The drastic ROS enhancement is associated with very low dose modifying factors for a survival fraction of 50%. This significant ROS enhancement effect by SAM-stabilized Fe3 O4 and CoFe2 O4 nanoparticles constitutes their excellent applicability in radiation therapy.


Subject(s)
Biocompatible Materials/chemistry , Breast Neoplasms/radiotherapy , Cobalt/chemistry , Ferric Compounds/chemistry , Magnetite Nanoparticles/chemistry , Reactive Oxygen Species/metabolism , Water/chemistry , Cell Survival , Cobalt/analysis , Dynamic Light Scattering , Female , Fluoresceins/chemistry , Human Umbilical Vein Endothelial Cells/metabolism , Humans , Imidazoles/chemistry , Ions , Magnetite Nanoparticles/ultrastructure , Static Electricity
12.
Biochem Biophys Res Commun ; 498(4): 855-861, 2018 04 15.
Article in English | MEDLINE | ID: mdl-29551683

ABSTRACT

Silicon nanoparticles with sizes between were synthesized through wet-chemistry procedures using diverse phase transfer reagents. On the other hand, the preparation of iron-doped silicon nanoparticles was carried out using the precursor Na4Si4 containing 5% Fe. Biocompatibility of all silicon nanoparticle samples was achieved by surface-stabilizing with (3-aminopropyl)triethoxysilane. These surface structures provided positive surface charges which facilitated electrostatic binding to the negatively charged biological membranes. The mode of interaction with membranes, being either incorporation or just attachment, was found to depend on the nanoparticle size. The smallest silicon nanoparticles (ca. 1.5 nm) were embedded in the mitochondrial membrane in MCF-7 cells. When interacting with X-rays these silicon nanoparticles were observed to enhance the superoxide formation upon depolarizing the mitochondrial membrane. X-ray irradiation of MCF-7 cells loaded with the larger silicon nanoparticles was shown to increase the intracellular singlet oxygen generation. The doping of the silicon nanoparticles with iron led to additional production of hydroxyl radicals via the Fenton reaction.


Subject(s)
Nanoparticles/metabolism , Radiation-Sensitizing Agents/chemistry , Radiotherapy/methods , X-Rays , Cell Membrane/metabolism , Humans , Hydroxyl Radical/metabolism , Intracellular Membranes/metabolism , Iron , MCF-7 Cells , Nanoparticles/chemistry , Propylamines , Silanes , Silicon , Static Electricity , Superoxides/metabolism , Surface Properties
13.
ACS Appl Bio Mater ; 1(6): 2002-2011, 2018 Dec 17.
Article in English | MEDLINE | ID: mdl-34996262

ABSTRACT

Au-Fe3O4 nanoheterodimers were obtained by thermally decomposing iron oleate on presynthesized gold nanoparticles. Water solubility as well as surface charges were achieved by encapsulating the initially hydrophobic Au-Fe3O4 nanoheterodimers in a self-assembled bilayer shell formed either by 1-octadecylpyridinium, providing positive surface charges, or by 4-dodecylbenzenesulfonate, yielding a negatively charged surface. The surface charge and surface architecture were shown to control both the cellular entry and the intracellular trafficking of the Au-Fe3O4 nanoheterodimers. The positively charged (1-octylpyridinium-terminated) Au-Fe3O4 nanoheterodimers were internalized by both breast cancer cells (MCF-7) and epithelial cells (MCF-10 A), wherein they were electrostatically bound at the negatively charged membranes of the cell organelles and, in particular, adsorbed onto the mitochondrial membrane. The treatment of MCF-7 and MCF-10 cells with a fractional X-radiation dose of 1 Gy resulted into a large increase of superoxide production, which arose from the Au-Fe3O4 nanoheterodimer-induced mitochondrial depolarization. In contrast, the negatively charged (4-dodecylbenzenesulfonate-terminated) Au-Fe3O4 nanoheterodimers preferentially invaded the cancerous MCF-7 cells by direct permeation. X-ray treatment of MCF-7 cells, loaded with anionic Au-Fe3O4 nanoheterodimers, yielded the increase of both hydroxyl radical and cytoplasmic superoxide formation. The X-radiation-induced activation of the Fe3O4 surfaces, consisting of Fe2+ and Fe3+ cations, triggered the catalysis of the hydroxyl radical production, whereas superoxide formation presumably occurred through X-ray-induced photoelectron emission near the Au surface. Since hydroxyl radicals are highly cytotoxic and the negatively charged Au-Fe3O4 NHDs spare the healthy MCF-10A cells, these Au-Fe3O4 nanoheterodimers exhibit a higher potential for radiation therapy than the positively charged Au-Fe3O4 nanoheterodimers. Encouraging results from the clonogenic cell survival assay and DMF calculations corroborate the excellent performance of the anionic Au-Fe3O4 nanoheterodimers as an X-ray dosage enhancer.

14.
Dtsch Med Wochenschr ; 142(12): 873-881, 2017 Jun.
Article in German | MEDLINE | ID: mdl-28637072

ABSTRACT

There are a vast number of complementary and alternative medicines (CAM) in oncology. Also patients' needs for information on these methods are growing. Helping patients to classify and evaluate CAM methods is a challenge. The Cancer Information Service at the German Cancer Research Center has developed a benefit-risk-assessment based on evidence-based medicine and individual patient traits: To rate a CAM's benefit, the scientific evidence and the patient's therapeutic goals have to be taken into account. To estimate its risks, both, the method itself and the patient's status of health must be considered.


Subject(s)
Complementary Therapies/classification , Neoplasms/therapy , Outcome and Process Assessment, Health Care , Antineoplastic Agents, Phytogenic/adverse effects , Antineoplastic Agents, Phytogenic/therapeutic use , Complementary Therapies/adverse effects , Evidence-Based Medicine , Germany , Humans , Neoplasms/mortality , Patient Education as Topic , Plant Extracts/adverse effects , Plant Extracts/therapeutic use , Quality of Life , Randomized Controlled Trials as Topic , Risk Assessment , Survival Rate
15.
J Mater Chem B ; 5(43): 8591-8599, 2017 Nov 21.
Article in English | MEDLINE | ID: mdl-32264527

ABSTRACT

Assemblies of inorganic nanoparticles and carbon nanodots have emerged as promising candidates for hybrid materials in biomedical applications. In this work, the formation and properties of gold nanoparticles synthesized with the aid of carbon nanodots (CND) as reducing/stabilizing agents was investigated. Through careful modification of the reaction conditions, such as precursor concentrations and temperature, the size and shape of the particles can be controlled. In general, CNDs provide reductive sites at which gold seeds can be formed. As the gold nanoparticles grow, the CNDs form a polar solubilizing shell in the polar aqueous environment, yielding bulbous Au@pCND nanoclusters. In fact, charge-transfer interactions between the pCND shell and the Au core are implicit, as confirmed by steady state and time resolved absorption and fluorescence spectroscopies. Finally, this work demonstrated via in cell internalization tests that the size and the shape of the Au@pCND nanoclusters play a crucial role for the cancer cell toxicity. Also the Au@pCND prove to be good candidates as sensitizers in cancer radio-therapy.

16.
J Phys Chem B ; 118(23): 6159-66, 2014 Jun 12.
Article in English | MEDLINE | ID: mdl-24827589

ABSTRACT

Superparamagnetic iron oxide nanoparticles (SPIONs) with a mixed phase composition (γ-Fe2O3)(1-x)(Fe3O4)x and sizes between 9 and 20 nm were synthesized via coprecipitation and were either left uncoated or subsequently surface-stabilized with citrate or malate anions. The sizes, morphology, surface chemistry, and magnetic properties of the nanoparticles were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and superconducting quantum interference device measurements, respectively. Cellular uptake and intracellular distribution in normal tissue and tumor cells were verified by TEM images. X-ray-induced changes of the oxidation state and site geometries of surface iron ions of uncoated and citrate-coated SPIONs were explored by collecting Fe K-edge X-ray absorption spectroscopy data. The potential applicability of citrate- and malate-coated SPIONs as an X-ray enhancer for radiation cancer therapy was substantiated by their drastic enhancement of the concentration of reactive oxygen species (ROS) in X-ray irradiated tumor cells.


Subject(s)
Ferric Compounds/chemistry , Nanoparticles/chemistry , Radiation-Sensitizing Agents/chemistry , Radiotherapy/methods , 3T3 Cells , Animals , Anions/chemistry , Caco-2 Cells , Cell Survival/drug effects , Cell Survival/radiation effects , Citric Acid/chemistry , Ferric Compounds/metabolism , Ferric Compounds/therapeutic use , Humans , MCF-7 Cells , Magnetic Phenomena , Malates/chemistry , Materials Testing , Mice , Nanoparticles/metabolism , Nanoparticles/therapeutic use , Oxidation-Reduction/radiation effects , Particle Size , Radiation-Sensitizing Agents/metabolism , Radiation-Sensitizing Agents/therapeutic use , Radiotherapy Dosage , Reactive Oxygen Species/metabolism , Surface Properties , X-Rays
17.
Biochem Biophys Res Commun ; 434(2): 217-22, 2013 May 03.
Article in English | MEDLINE | ID: mdl-23535374

ABSTRACT

The applicability of ultrasmall uncapped and aminosilanized oxidized silicon nanoparticles (SiNPs and NH2-SiNPs) as radiosensitizer was studied by internalizing these nanoparticles into human breast cancer (MCF-7) and mouse fibroblast cells (3T3) that were exposed to X-rays at a single dose of 3 Gy. While SiNPs did not increase the production of reactive oxygen species (ROS) in X-ray treated cells, the NH2-SiNPs significantly enhanced the ROS formation. This is due to the amino functionality as providing positive surface charges in aqueous environment. The NH2-SiNPs were observed to penetrate into the mitochondrial membrane, wherein these nanoparticles provoked oxidative stress. The NH2-SiNPs induced mitochondrial ROS production was confirmed by the determination of an increased malondialdehyde level as representing a gauge for the extent of membrane lipid peroxidation. X-ray exposure of NH2-SiNPs incubated MCF-7 and 3T3 cells increased the ROS concentration for 180%, and 120%, respectively. Complementary cytotoxicity studies demonstrate that these silicon nanoparticles are more cytotoxic for MCF-7 than for 3T3 cells.


Subject(s)
Nanoparticles/therapeutic use , Radiation-Sensitizing Agents/therapeutic use , Silicon/therapeutic use , 3T3 Cells , Animals , Antineoplastic Agents/therapeutic use , Cell Survival/drug effects , Cytosol/chemistry , Drug Screening Assays, Antitumor/methods , Humans , MCF-7 Cells , Mice , Microscopy, Electron, Transmission , Mitochondria/chemistry , Mitochondria/drug effects , Mitochondrial Membranes/chemistry , Mitochondrial Membranes/drug effects , Nanoparticles/chemistry , Nanotechnology/methods , Neoplasms/drug therapy , Neoplasms/pathology , Neoplasms/radiotherapy , Oxidation-Reduction , Oxidative Stress , Particle Size , Radiation-Sensitizing Agents/chemistry , Reactive Oxygen Species/chemistry , Silicon/chemistry , X-Rays
18.
Biochem Biophys Res Commun ; 425(2): 393-7, 2012 Aug 24.
Article in English | MEDLINE | ID: mdl-22842461

ABSTRACT

Internalization of citrate-coated and uncoated superparamagnetic iron oxide nanoparticles by human breast cancer (MCF-7) cells was verified by transmission electron microscopy imaging. Cytotoxicity studies employing metabolic and trypan blue assays manifested their excellent biocompatibility. The production of reactive oxygen species in iron oxide nanoparticle loaded MCF-7 cells was explained to originate from both, the release of iron ions and their catalytically active surfaces. Both initiate the Fenton and Haber-Weiss reaction. Additional oxidative stress caused by X-ray irradiation of MCF-7 cells was attributed to the increase of catalytically active iron oxide nanoparticle surfaces.


Subject(s)
Ferric Compounds/pharmacology , Magnetite Nanoparticles , Neoplasms/metabolism , Radiation-Sensitizing Agents/pharmacology , Reactive Oxygen Species/metabolism , Cell Line, Tumor , Ferric Compounds/chemistry , Ferric Compounds/metabolism , Humans , Radiation-Sensitizing Agents/chemistry , Radiation-Sensitizing Agents/metabolism , X-Rays
19.
Nucl Med Biol ; 39(7): 1077-80, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22591915

ABSTRACT

INTRODUCTION: [(18)F]desmethoxyfallypride ([(18)F]DMFP) is a promising tracer for longitudinal assessment of striatal dopamine D2/D3-receptor (D2R) availability by positron emission tomography (PET) in small animal models. We explored the feasibility of [(18)F]DMFP-PET to image D2R availability in rat models of Huntington's (HD) and Parkinson's disease (PD). METHODS: Animals received either unilateral intrastriatal quinolinic acid lesions or medial forebrain bundle injections of 6-OHDA to produce the loss of striatal projection neurones or deplete the striatal dopamine, corresponding to established animal models for HD and PD, respectively. Three weeks after lesioning, PET scans were acquired on a microPET Focus 120 system following the tail vein injection of [(18)F]DMFP. RESULTS: [(18)F]DMFP-PET clearly visualized lesion induced decreases and increases of D2R availability. In vivo estimates of D2R binding and changes thereof gained by pharmacokinetic analyses correlated significantly with D2R density and its change provided by in vitro [(3)H]raclopride-autoradiography. CONCLUSIONS: In conclusion, [(18)F]DMFP-PET is a suitable method for in vivo D2R-assessment in preclinical research, e.g for monitoring cell-based therapies.


Subject(s)
Huntington Disease/metabolism , Parkinson Disease/metabolism , Positron-Emission Tomography/methods , Receptors, Dopamine D2/metabolism , Receptors, Dopamine D3/metabolism , Salicylamides , Animals , Disease Models, Animal , Huntington Disease/diagnostic imaging , Parkinson Disease/diagnostic imaging , Raclopride/metabolism , Radioactive Tracers , Rats
20.
BMC Gastroenterol ; 10: 76, 2010 Jul 08.
Article in English | MEDLINE | ID: mdl-20615248

ABSTRACT

BACKGROUND: The reprocessing of medical endoscopes is carried out using automatic cleaning and disinfection machines. The documentation and archiving of records of properly conducted reprocessing procedures is the last and increasingly important part of the reprocessing cycle for flexible endoscopes. METHODS: This report describes a new computer program designed to monitor and document the automatic reprocessing of flexible endoscopes and accessories in fully automatic washer-disinfectors; it does not contain nor compensate the manual cleaning step. The program implements national standards for the monitoring of hygiene in flexible endoscopes and the guidelines for the reprocessing of medical products. No FDA approval has been obtained up to now. The advantages of this newly developed computer program are firstly that it simplifies the documentation procedures of medical endoscopes and that it could be used universally with any washer-disinfector and that it is independent of the various interfaces and software products provided by the individual suppliers of washer-disinfectors. RESULTS: The computer program presented here has been tested on a total of four washer-disinfectors in more than 6000 medical examinations within 9 months. CONCLUSIONS: We present for the first time an electronic documentation system for automated washer-disinfectors for medical devices e.g. flexible endoscopes which can be used on any washer-disinfectors that documents the procedures involved in the automatic cleaning process and can be easily connected to most hospital documentation systems.


Subject(s)
Disinfection/standards , Documentation/methods , Endoscopes, Gastrointestinal/standards , Quality Assurance, Health Care/standards , Software , Equipment Contamination/prevention & control , Germany , Guidelines as Topic , Humans
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