Publications by authors named "Alfonsina Ramundo-Orlando"

Superparamagnetic iron oxide nanoparticles are used in a rapidly expanding number of research and practical applications in biotechnology and biomedicine. Recent developments in iron oxide nanoparticle design and understanding of nanoparticle membrane interactions have led to applications in magnetically triggered, liposome delivery vehicles with controlled structure. Here we study the effect of external physical stimuli-such as millimeter wave radiation-on the induced movement of giant lipid vesicles in suspension containing or not containing iron oxide maghemite (γ-FeO) nanoparticles (MNPs).

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Among the many biological effects caused by low intensity extremely high frequency electromagnetic fields (EHF-EMF) reported in the literature, those on the nervous system are a promising area for further research. The mechanisms by which these fields alter neural activity are still unclear and thus far there appears to be no frequency dependence regarding neuronal responses. Therefore, proper in vitro models for preliminary screening studies of the interaction between neural cells with EMF are needed.

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Our previous study of interaction between low intensity radiation at 53.37GHz and cell-size system - such as giant vesicles - indicated that a vectorial movement of vesicles was induced. This effect among others, i.

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Exposure of cell membranes to an electromagnetic field (EMF) in the millimeter wave band (30-300 GHz) can produce a variety of responses. Further, many of the vibrational modes in complex biomolecules fall in the 1-100 GHz range. In addition to fundamental scientific interest, this may have applications in the development of diagnostic and therapeutic medical applications.

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The interaction of millimeter wave radiation, in the 30-300 GHz range, with biological systems is a topic of great interest as many of the vibrational dynamics that occur in biochemical reactions of large macromolecules in living organisms fall in the 1-100 GHz range. Membranes and cellular organelles may have different ways of interacting with this radiation as well. In this article, we investigate the influence of 53.

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Due to the increasing interest in millimeter waves (MMW) applications in medicine and telecommunications, the investigation of their potential biological effects is of utmost importance. Here we report results of the study of interaction between low-intensity radiation at 53.37 GHz and giant vesicles.

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The effects of pulsed 130 GHz radiations on lipid membrane permeability were investigated by using cationic liposomes containing dipalmitoyl phosphatidylcholine (DPPC), cholesterol, and stearylamine. Carbonic anhydrase (CA) was loaded inside the liposomes and the substrate p-nitrophenyl acetate (p-NPA) added in the bulk aqueous phase. Upon permeation across the lipid bilayer, the trapped CA catalyzes the conversion of the p-NPA molecules into products.

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Intercellular communication mediated by gap junction channels plays an important role in many cellular processes. In contrast to other channels, gap junction channels span two plasma membranes resulting in an intracellular location for both ends of the junctional pore and the regulatory sites for channel gating. This configuration presents unique challenges for detailed experimental studies of junctional channel physiology and ligand-activation in situ.

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The effect of extremely low frequency and low amplitude magnetic fields on gap junctional permeability was investigated by using reconstituted connexin32 hemi channel in liposomes. Cytochrome c was loaded inside these proteoliposomes and its reduction upon addition of ascorbate in the bulk aqueous phase was adopted as the index of hemi channel permeability. The permeability rate of the hemi channels, expressed as DeltaA/min, was dependent on the incubation temperature of proteoliposomes.

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Previous observations reported by our group indicate that 2.45 GHz microwave fields at specific absorption rate (SAR) of 5.6 W/kg reduce the enzyme activity rate of ascorbate oxidase (AO) trapped in liposomes.

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