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Most lipid formulations need cholesterol for efficient transfection, but the precise motivation remains unclear. Here, we have investigated the effect of cholesterol on the transfection efficiency (TE) of cationic liposomes made of l, 2-dioleoyl-3-trimethylammonium-propane (DOTAP) and dioleoylphosphocholine (DOPC) in Chinese hamster ovary cells. The transfection mechanisms of cholesterol-containing lipoplexes have been investigated by TE, synchrotron small angle X-ray scattering (SAXS) and laser scanning confocal microscopy (LSCM) experiments. We prove that cholesterol-containing lipoplexes enter the cells using different endocytosis pathways. Formulations with high cholesterol content efficienlty escape from endosomes. These studies will contribute to the rational design of novel lipid nanocarriers with superior TE.

The authors examined relationships between quantified EEG (qEEG) variables and neuropsychological performance in 54 consecutive patients with probable Alzheimer's disease (AD). Patients were studied with qEEG and a neuropsychological battery that assessed memory, attention, verbal functions, set-shifting abilities, and procedural learning. More severe memory, attention, and verbal deficits were significantly correlated with lower alpha relative power, and increased theta relative power was significantly correlated with poor set-shifting abilities. No qEEG variables were significantly correlated with the procedural learning task. These correlations between deficits in specific cognitive domains and qEEG bands suggest that qEEG may have an important role in the investigation of the cognitive deficits in AD.

We examined the presence of quantified electroencephalographic (qEEG) differences between Parkinson's disease (PD) patients with and without dementia, and a group of age-comparable normal controls. While there were no significant differences in relative power in any of the qEEG bands between PD patients without dementia and normal controls, PD patients showed a significantly greater reactivity in the alpha band. On the other hand, PD patients with dementia showed significantly less alpha and more theta relative power than both the normal control and the PD without dementia groups. When PD patients with dementia were compared with a group of patients with Alzheimer's disease (AD) and a similar severity of dementia, no significant between-group differences were found in any of the qEEG bands. In conclusion, while our study demonstrated no significant qEEG differences between non-demented PD patients and normal controls, PD patients with dementia showed qEEG changes similar to those observed in patients with AD.

We used Fourier Transibrm Infrared Spectroscopy (FTIR) combined with flow cytometry to study the apoptosis and necrosis processes in Jurkat, a lymphocyte cell lìne. The apoptosis was induced in the cells by a chemical agent, the actinomycin D, while the necrosis was induced lowering the pH value to 4.2. The apoptotic events were analysed by flow cytometry (using annexin V and propidium iodide) and contemporary monitored by FTIR spectroscopy at diflèrent times after the treatment. This comparison allowed us to find in the IR spectrum, between 3000 cm 1 and 2800 c--1, a "marker band" of the apoptosis corresponding to the exposure of phosphatidylserine on the outer leaflet of the membrane. A marker of a specific cellular process obtained by using a non-destructive technique such as FTIR spectroscopy, has a great signifìcance in the diagnostic medicine providing a tool for detecting pathologies in vivo.

In the present study, we investigated the effect of the interaction of electromagnetic radiation with human keratinocytes (HaCaT)at low frequency. HaCaT cells were exposed to a sinusoidal magnetic field at a density of 2 mT (50 Hz)These cells are a good model for studying interaction of non-ionising radiation, because they are totally open to electromagnetic waves and also because they are resistant to both mechanical and thermal stimuli. We performed scanning microscopy which showed modification in shape and morphology in exposed cells. This modification is related to differential actin distribution as revealed by phalloidin fluorescence analysis. Moreover, 50 Hz exposed cells show increased clonogenic capacity, as well as increased cellular growth as showed by clonogenicity assays and growth curves. Indirect immunofluorescence analysis using a fluorescent antibody against involucrin and b4 integrin differentiation and adhesion markers respectively, revealed an increase of involucrin expression and segregation of b4 integrin in the cell membrane in 50 Hz exposed cells, suggesting that a higher percentage of the exposed cells shows a modified pattern of adhesion and differentiation markers. We also present evidence that electromagnetic field (EMF) exposure of HaCaT cells can interfere with protein kinase activity. Our observations confirm the hypothesis that electromagnetic fields, at 50 Hz may modify cell membrane morphology and interfere with initiation of the signal cascade pathway, and cellular adhesion.

In this work we employed Atomic Force Microscopy (AFM) and Scanning Near-field Optical Microscopy (SNOM) techniques to study the effect of the interaction between human keratinocytes (HaCaT) and electromagnetic fields at low frequency. HaCaT cells were exposed to a sinusoidal magnetic field at a density of 50 Hz, 1mT. We performed AFM analysis showed modification in shape and morphology in exposed cells with an increase of the areas of adhesion between cells. This last evidence has been confirmed by SNOM indirect immunofluorescence analysis performed with a fluorescent antibody against the adhesion marker b4 integrin, which revealed an increase of b4 integrin segregation in the cell membrane of 50 Hz exposed cells, suggesting that a higher percentage of these cells shows a modified pattern of this adhesion marker

Air operating atomic force microscopy has been used to study human B lymphoblastoid (Raji) cells exposed to a 50 Hz 2 mT sinusoidal magnetic field (MF), up to 64 h. A statistical analysis performed on mean height and membrane roughness of the cells showed a loss of microvilli and several modifications of the overall shape and membrane surface at

The authors examined the presence of specific quantified electroencephalographic (qEEG) changes in dementia patients with relatively lower frontal or parietal blood perfusion as demonstrated by SPECT. Over all brain regions, patients with relatively lower parietal perfusion showed significantly higher theta relative power than demented patients with relatively lower frontal perfusion or normal control subjects. Dementia patients with relatively lower frontal perfusion showed no differences from age-comparable normal control subjects in qEEG variables. These findings 1) suggest that usefulness of qEEG for the diagnosis of dementia is restricted to a subgroup of patients with the typical SPECT pattern of parietal blood hypoperfusion and 2) demonstrate that the qEEG changes typical of dementia are not related to perfusion deficits in frontal brain areas.

Fusion of Epstein-Barr virus (EBV) with Raji cells was measured after exposure of the virus to neutral or low pH, enzymatic modification of the viral spike glycoproteins, or chemical modification of the target membrane. The relief of octadecylrhodamine (R18) fluorescence self-quenching was used to monitor fusion. Fusion of EBV with Raji cells at pH 5.9 was significantly enhanced compared to that at neutral pH. Treatment of Raji cells with agents known to modify the surface net charge (trinitrobenzene sulfonic acid) totally prevented fusion at a neutral pH. Desialylation of EBV significantly reduced the extent of fusion with Raji cells. Our results demonstrate that EBV is rapidly internalized and then fuses with lymphoblastoid cells in the endocytic vesicles.