BACKGROUND: Amoebiasis is a major public health problem in tropical and subtropical countries. Currently, metronidazole is the gold choice medication for the treatment of this disease. However, reports have indicated towards the possibility of development of metronidazole-resistance in Entamoeba strains in near future. In view of the emergence of this ...

Macrolides are stereospecific macrolactones of high molecular weights. Herein, 600 mostly semisynthetic macrolides are compared with 50,000 small non-macrolide synthetic molecules in terms of measured physicochemical properties in order to assess the drug-likeness and developability chances of macrolides. The pre-selected set of diverse macrolides is comprised mostly of derivatives of ...

Helicobacter pylori (H. pylori) infection is an etiologic cause of gastric disorders worldwide. H. pylori has been shown to assimilate and convert host cholesterol into cholesteryl glucosides (CGs) by cholesterol-α-glucosyltransferase encoded by capJ. Here, we show that capJ-knockout (ΔcapJ) H. pylori resulted in greatly reduced type IV secretion system (TFSS)-associated ...

The gastric pathogen Helicobacter pylori sheds outer membrane vesicles (OMV) that possess many of the surface elements of the bacterium. Here we review current knowledge on the composition of H. pylori OMV and discuss evidence for their potential roles in bacterial survival and pathogenesis.

Biomembrane lipid composition and lateral heterogeneity vary significantly both spatially and temporally and have been shown to be associated with cell functions. Lipid raft-based membrane heterogeneity might be involved with cell physiological and pathological processes. Therefore, there is a great need to investigate the roles of lipid composition and lateral ...

T cell membrane receptors and signaling molecules assemble at the immunological synapse (IS) in a supramolecular activation cluster (SMAC), organized into two differentiated subdomains: the central SMAC (cSMAC), with the TCR, Lck, and linker for activation of T cells (LAT), and the peripheral SMAC (pSMAC), with adhesion molecules. The mechanism ...

A serious drawback of ESR, particularly in its application to cells, is the lack of information on the location of spin probes in the system. In order to realize real time tracking, a spin probe was combined with a fluorophore in a new kind of nitroxide-fluorophore double probe which, in ...

Methyl-β-cyclodextrins (MβCDs) are molecules that are extensively used to remove and to load cholesterol (Chol) from artificial and natural membranes; however, the mechanism of Chol extraction by MβCD from pure lipids or from complex mixtures is not fully understood. One of the outstanding questions in this field is the capability ...

We report on the association capability of a novel multisegmented, multiarm star terpolymer to form a diversity of pH-responsive amphoteric micellar nanostructured self-assemblies.

Silver nanoparticles (SNP) are the subject of worldwide commercialization because of their antimicrobial effects. Yet only little data on their mode of action exist. Further, only few techniques allow for visualization and quantification of unlabeled nanoparticles inside cells. To study SNP of different sizes and coatings within human macrophages, we ...

The visual cycle is a multi-step pathway to recycle 11-cis retinal, the chromophore for both rod and cone visual pigments. The isomerohydrolase RPE65, a membrane-associated enzyme, converts all-trans retinyl ester (atRE) to 11-cis retinol, a key step in the visual cycle. Previously, it has been shown that membrane association of ...

For more than half a century, electron microscopy has been a main tool for investigating the complex ultrastructure and organization of chloroplast thylakoid membranes, but, even today, the three-dimensional relationship between stroma and grana thylakoids, and the arrangement of the membrane protein complexes within them are not fully understood. Electron ...

Neurotransmitter release at the synapse requires fusion of synaptic vesicles with the presynaptic plasma membrane. SNAREs are the core constituents of the protein machinery responsible for this membrane fusion, but the actual fusion mechanism remains unclear. Here, we have simulated neuronal SNARE-mediated membrane fusion in molecular detail. In our simulations, ...

Glutamate-mediated neurotransmission through ligand-gated, ionotropic glutamate receptors is the main form of excitatory neurotransmission in the vertebrate central nervous system where it plays central roles in learning, memory and a variety of disorders. Acting as auxiliary subunits, transmembrane α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) regulatory proteins (TARPs) are essential regulators for ...

Rhodopsin is a prototypical G protein-coupled receptor (GPCR) - a member of the superfamily that shares a similar structural architecture consisting of seven-transmembrane helices and propagates various signals across biological membranes. Rhodopsin is embedded in the lipid bilayer of specialized disk membranes in the outer segments of retinal rod photoreceptor ...

An innovative photoresponsive cerasome is fabricated by sol-gel process in combination of self-assembly technique from a molecularly designed organoalkoxysilylated lipid containing an azobenzene unit, which is able to operate as a "valve" with an "on-off" function under specific stimuli to control the release of loaded guest molecules from the liposomal ...

Peripapillary choroidal neovascular membranes (PCNM) are defined as a collection of new choroidal blood vessels, any portion of which lies within one disc diameter of the nerve head. There are two types of PCNM, and correct pre-interventional identification of growth site has been shown to stratify the chance of visual ...

Disposable dipstick-type DNA biosensors in the form of lateral flow strips are particularly useful for genotyping in a small laboratory or for field testing due to their simplicity, low cost and portability. Their unique advantage is that they enable visual detection in minutes without the use of instruments. In addition, the ...

Genistein (5,7,4'-trihydroxyisoflavone) the common soy beans isoflavone has attracted scientific interest due to its antioxidant, estrogenic, antiangiogenic and aniticancer activities. The aim of the present study was to investigate the interaction of genistein with biological (erythrocyte) and model membranes (dimyristoyl- and dipalmitoylphosphatidylcholine). Using Laurdan and Prodan as fluorescent probes, we ...

To evaluate retroprosthetic membranes that can occur in 25% to 65% of patients with the Boston type 1 keratoprosthesis (KPro). Two patients with Peter anomaly and 2 with neurotrophic scarred corneas underwent revisions of their type 1 KPros because of visually compromising retroprosthetic membranes. The excised membranes were studied by ...

The interaction between Eu(III) tris-β-diketonato coordination complexes (EC), displaying antitumor activity, and lipid vesicles composed of zwitterionic lipid phosphatidylcholine has been studied using fluorescence spectroscopy techniques. To characterize EC-membrane binding, several fluorescent probes, including pyrene, Prodan and 1,6-diphenyl-1,3,5-hexatriene, have been employed. It has been found that EC display effective partitioning ...

Membrane fouling is the major drawback of membrane-based technologies because it will lead to severe flux declines and the need to clean or replace the fouled membrane. A technique capable of early diagnosis, process monitoring, and evaluation of the role of different foulants playing in the fouling process is crucial ...

We discover that a synergistically amplifying role of stabilizing membrane proteins and continuous lipid recycling can explain the physics governing the stability, polydispersity, and dynamics of lipid raft domains in plasma membranes of biological cells. We establish the conjecture using a generalized order parameter based on theoretical formalism, endorsed by ...

The relationship between acidic pH, taste cell pH(i), and chorda tympani (CT) nerve responses was investigated before and after incorporating the K(+)-H(+) exchanger, nigericin, in the apical membrane of taste cells. CT responses were recorded in anesthetized rats in vivo, and changes in pH(i) were monitored in polarized fungiform taste ...

The first CdSe/ZnS quantum dot photoluminescence lifetime-based pH nanosensor has been developed. The average lifetime of mercaptopropionic acid-capped QD nanosensors showed a linear response in the pH range of 5.2-6.9. These nanosensors have been satisfactorily applied for pH estimation in simulated intracellular media, with high sensitivity and high selectivity toward ...

Complexin binds the SNARE complex at synapses and regulates exocytosis, but genetic studies indicate contradictory roles: in flies it predominantly inhibits synaptic vesicle fusion, whereas in mice it promotes evoked responses. Here we characterize the complexin mutant in the nematode Caenorhabditis elegans and reveal bipolar functions in neurotransmission: complexin inhibits ...

Second-harmonic generation (SHG) by membrane-incorporated probes is a nonlinear optical signal that is voltage-sensitive and the basis of a sensitive method for imaging membrane potential. The voltage dependence of SHG by four different probes, three retinoids (all-trans retinal), and two new retinal analogs, 3-methyl-7-(4'-dimethylamino-phenyl)-2,4,6-heptatrienal (AR-3) and 3,7-dimethyl-9-(4'-dimethylamino-phenyl)-2,4,6,8-nonatetraenal (AR-4), and a ...

This chapter describes a method for the measurement of the electrostatic potential at the electrical double layer surrounding a nanoparticle in solution. This is referred to as the zeta potential. Nanoparticles with a zeta potential between -10 and +10 mV are considered approximately neutral, while nanoparticles with zeta potentials of ...

Treatment of a pathological spinal disc in vivo by injection of protein crosslinking reagents to restore the disc's mechanical properties is a new approach to the treatment of degenerative disc disease. In this study, the thermal stability of the collagen in disc annulus was measured by differential scanning calorimetry following ...

Membrane proteins are key molecules in the cell and are important targets for drug development. Much effort has, therefore, been directed towards research of this group of proteins, but their hydrophobic nature can make working with them challenging. Here we discuss methodologies used in the study of the membrane proteome, ...

We report a single-vesicle approach to compare the all-or-none and graded mechanisms of lipid bilayer permeabilization by CpreTM and NpreTM, two peptides derived from the membrane-proximal external region of the HIV fusion glycoprotein gp41 subunit. According to bulk requenching assays, these peptides permeabilize large unilamellar vesicles via all-or-none and graded ...

The aim of this study was to evaluate 4-META/MMA-TBB resin as an alternative to sling sutures for fixation of membrane to tooth in GTR in terms of its effect on tissue regeneration. Dehiscence periodontal defects were created in 6 dogs which were divided at random into two groups, 3 dogs ...

Using polymethylmethacrylate (PMMA) cement in cemented endoprostheses may cause heat necrosis and prosthesis failure due to the highly exothermic reaction. This study determined the magnitude and duration of temperature change during the cementation of a mandibular endoprosthesis in an in vitro and in vivo Macaca fasicularis model. In the in ...

This study investigated the use of ultrasound image analysis in quantifying temperature changes in tissue, both ex vivo and in vivo, undergoing local hyperthermia. Temperature estimation is based on the thermal dependence of the acoustic speed in a heated medium. Because standard beam-forming algorithms on clinical ultrasound scanners assume a ...

Auxin levels are well regulated in cells and tissues by both transport and local biosynthesis, and its distribution is important for the modulation of cell proliferation, differentiation, development, tropisms and high-temperature response. Activation of auxin biosynthesis with increased temperatures reported in certain plant tissues. In contrast, our studies indicated that ...

An experimental investigation is carried out to develop a novel approach to cryosurgery, where laser heating counteracts tissue freezing to better confine damage to the targeted cancerous tissue within a lethal low-temperature isothermal boundary-an approach we refer to as laser-assisted cryosurgery (LAC). The advantage of this procedure relative to conventional ...

In our previous study, we used optical coherence tomography (OCT) and reported an increase in signal intensity of depth profiles between euthanasia injection and cardiac arrest (CA), demonstrating the potential as a tool for monitoring/diagnosing brain tissue viability [Appl. Opt.48, 4354 (2009)]. Here, for the first time to our knowledge, ...

We have previously proposed the use of Doppler ultrasound to noninvasively stage a sinus infection. In this study, we first investigated the acoustic properties of nonpurulent and mucopurulent sinus secretions. The density, viscosity, speed of sound and attenuation of 18 samples of sinus fluid were examined. We then assessed the ...

To establish proof of concept in tissue, using the exothermic neutralization reaction of acetic acid and sodium hydroxide in ex vivo porcine liver and to conduct an initial probe into the relationships of volume and concentration of reagents to temperatures and the areas affected. A total of 0.5 mL or ...

The ultrasonic harmonic scalpel (HS) uses ultrasound energy to achieve surgical dissection. To test the feasibility of limited HS reuse and to insure that reprocessed HS function in a substantially equivalent manner to their new counterparts, this study compared in vivo mesenteric vessel and liver cutting characteristics, scalpel shaft temperatures ...

Temperature distribution in tissues behind ribs produced by weakly focused ultrasound had been calculated using Pennes bioheat equation and the validity of the theoretical model was experimentally confirmed in vitro using porcine live. We found that the position of the maximum temperature in tissue is strongly influenced by the distance ...

Overlapping ablations can be used to increase radiofrequency ablation volume. Our goal was to determine, in a porcine model, the relationship of ablation size and temperature for single ablation, and to compare the extent of necrosis resulting from temperature-dependent electrode positioning versus fixed-distance dual ablation. The experiments were performed in ...

Carbon nanotubes have many potential applications in life sciences and engineering as they have very high absorbance in the near-infrared (NIR) spectrum, while biological tissues do not. The purpose of this study was to determine the effect of 1064 nm NIR laser power levels on the spatial temperature distribution and ...

Purpose: To assess the relationship between the radiofrequency (RF) output power and the intra-oesophageal temperature for hyperthermia of the whole thoracic region, and also to evaluate the patients' characteristics associated with adequate heating. Materials and methods: Fifty-nine patients with thoracic cancer treated with radiotherapy plus hyperthermia were retrospectively analysed. The ...

This review focuses on new data from recent publications concerning how compounding interactions between different thermoregulatory pathways influence the development of hyperthermia and/or neuroleptic malignant syndrome (NMS), and the fundamental issue of the presumed causal role of antipsychotic drugs. The formal criteria for substantiating cause-effect relationships in medical science, established ...

Sodium hypochlorite is the most commonly used endodontic irrigant because of its antimicrobial and tissue-dissolving activity. The aim of this study was to evaluate and compare the effects of concentration, temperature, and agitation on the tissue-dissolving ability of sodium hypochlorite. In addition, a hypochlorite product with added surface active agent ...

PURPOSE: Hyperthermia treatment planning (HTP) potentially provides a valuable tool for monitoring and optimization of treatment. However, one of the major problems in HTP is that different sources of uncertainty degrade its reliability. Perfusion uncertainty is one of the largest uncertainties and hence there is an ongoing debate whether optimization ...

There are two important factors that accompany heat-induced shrinkage of collagenous tissues: mechanical property degradation and partial recovery from the shrunken length (elongation) upon returning to room temperature (defined here as acute recovery). These undesirable factors reduce the efficacy of thermal therapies. We applied chemical cross-linking adjuvant to thermal treatment ...

There is no currently available technology to accurately predict ablation lesion size within seconds of onset of delivery of radiofrequency (RF) energy. Changes in several biophysical characteristics of cardiac tissue in vitro within 5-15 seconds of the onset of RF energy were evaluated to predict lesion formation at 120 seconds. ...

To determine the expected ablation zone size and associated isotherms when using clinically available percutaneous cryoprobes for pulmonary cryoablation in a porcine lung model. Seven ablations were performed in the lungs of three adult pigs using clinically available 2.4-mm cryoprobes (Endocare, Inc, Irvine, California) and a 10-minute double-freeze protocol. Five ...