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1.
J Laryngol Otol ; 132(2): 162-167, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29248029

ABSTRACT

OBJECTIVE: The imaging of stones in the salivary glands and ducts poses a challenge, even to experienced ultrasound examiners. This study investigated whether the 'twinkling artefact', which occurs at internal calcific foci during Doppler ultrasound examinations, is useful for detecting salivary gland stones. METHODS: In a model test, 20 salivary stones were analysed in vitro, via Doppler ultrasound, with regard to their representability and the triggering of the twinkling artefact. In a follow-up study, 28 patients with sialolithiasis and food-related large salivary gland swellings were examined, using both power and colour Doppler modes, with regard to the twinkling artefact. All ultrasound examinations were performed by an experienced examiner and retrospectively graded by two experienced sonographers. RESULTS: All stones could reliably be detected using the twinkling artefact in the model test. Twenty-seven of 28 salivary stones (96 per cent) also showed twinkling in vivo, during patient assessment. The power Doppler mode showed a significantly higher intensity level of twinkling than the colour Doppler mode (p < 0.0001). CONCLUSION: The twinkling artefact is a very reliable sign for the diagnosis of sialolithiasis. Power Doppler is superior to colour Doppler for detection of the twinkling artefact.


Subject(s)
Artifacts , Salivary Gland Calculi/diagnostic imaging , Salivary Glands/diagnostic imaging , Ultrasonography, Doppler, Color , Adolescent , Adult , Aged , Female , Follow-Up Studies , Humans , In Vitro Techniques , Male , Middle Aged , Predictive Value of Tests , Retrospective Studies , Sensitivity and Specificity , Ultrasonography, Doppler, Color/methods
2.
J Nutr Health Aging ; 19(3): 258-64, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25732209

ABSTRACT

OBJECTIVES: Older adults often suffer from vitamin D deficiency and from the frailty syndrome charac-terized by different physical limitations, complicating independent everyday life. Previous studies have suggested a relationship between vitamin D status and the frailty syndrome, but results have been partly inconsistent, particularly regarding the shape of the association. Therefore, our aim was to further assess the association of 25-hydroxyvitamin D (25(OH)D) serum levels and frailty in older participants. DESIGN: Cross-sectional population-based study. PARTICIPANTS: The study population included 478 men and 462 women of the KORA (COoperative health research in the Region of Augsburg)-Age study born before 1944 examined in 2009. MEASUREMENTS: Classification of participants into different frailty states was performed according to the following criteria: weight loss, exhaustion, physical inactivity, slowness, and weakness. PARTICIPANTS who met 1-2 or ≥ 3 of the 5 criteria were classified as prefrail or frail, respectively. Total 25(OH)D was measured in non-fasting serum samples with an enhanced chemiluminescence immunoassay. Sequential logistic regression models adjusted for age, sex, season, lifestyle factors, diseases and biomarkers including parathyroid hormone (PTH) were calculated. RESULTS: High levels of 25(OH)D were inversely associated with being prefrail (N=351) or frail (N=38) in the model adjusted for age, sex, season and lifestyle factors. Compared to levels <15 ng/ml, odds ratios (ORs) (95% confidence intervals (CIs) were 0.52 (0.34-0.78) for levels of 15-<20 ng/ml, 0.55 (0.37-0.81) for levels of 20-<30 ng/ml and 0.32 (0.21-0.51) for levels ≥ 30 ng/ml. Additional adjustment for potential mediators including PTH only slightly attenuated these associations. For single frailty-components, significantly decreased ORs were found for exhaustion, physical inactivity and slowness comparing 25(OH)D levels ≥ 30 ng/ml with levels <15 ng/ml. CONCLUSION: Subjects with 25(OH)D serum levels ≥ 15 ng/ml were less frequently prefrail or frail.


Subject(s)
Frail Elderly , Health Surveys , Vitamin D Deficiency/blood , Vitamin D/analogs & derivatives , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Logistic Models , Male , Odds Ratio , Parathyroid Hormone/blood , Vitamin D/blood
3.
Chem Phys Lipids ; 186: 39-44, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25532812

ABSTRACT

We have enhanced the rapid solvent exchange (RSE) apparatus by adding controls in temperature, evacuation speed and vortex velocity. Following published protocols yielded vesicles of diverse size and lamellarity as detected by differential scanning calorimetry, photon correlation spectroscopy and X-ray experiments. To optimize the net production of multilamellar vesicles (MLVs) we varied in addition to vortex and evacuation speed lipid and organic solvent concentration, as well as composition of the aqueous medium. Reducing vortexing frequencies and speed of degassing were most beneficial for the yield in MLVs. Additionally also high lipid concentrations and organic solvent/buffer ratios supported MLV formation. To explain our findings we hypothesize on the role of microscopic instabilities on the aqueous phase, which may act as molds for vesicle formation.


Subject(s)
1,2-Dipalmitoylphosphatidylcholine/chemistry , Liposomes/chemistry , Calorimetry, Differential Scanning , Equipment Design , Solvents , Temperature , Thermodynamics
4.
Br J Dermatol ; 168(4): 825-36, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23252768

ABSTRACT

BACKGROUND: Two phase III trials of photodynamic therapy (PDT) with BF-200 ALA, a recently approved nanoemulsion formulation of 5-aminolaevulinic acid (ALA) demonstrated high clearance rates in mild-to-moderate actinic keratosis (AK). The comparison to a registered methyl aminolaevulinate (MAL) cream demonstrated significantly superior total patient clearance rates. OBJECTIVES: To evaluate long-term efficacy and safety of PDT for AK 6 and 12 months after the last PDT with BF-200 ALA, MAL or placebo. METHODS: The follow-up phase (FUP) was performed with patients of two phase III studies. Both studies compared BF-200 ALA with placebo, one of the studies additionally with MAL. Overall recurrence rates and various subgroups (light source, lesion severity, lesion location, complete responders after first PDT) were assessed 6 and 12 months after the last PDT. RESULTS: Recurrence rates were similar for BF-200 ALA and MAL, with a tendency to lower recurrence rates for BF-200 ALA. The proportion of patients who were fully cleared during PDT and remained completely clear for at least 12 months after PDT were 47% for BF-200 ALA (both studies) and 36% for MAL treatment. The subgroup that was illuminated with narrow wavelength LED lamps reached 69% and 53% for BF-200 ALA (both studies, respectively) and 41% for MAL. No safety concerns were reported. CONCLUSIONS: The FUP data confirmed the high efficacy and safety of PDT with BF-200 ALA. The slightly lower recurrence rates after BF-200 ALA treatment compared with MAL treatment enhanced the better treatment outcome due to the significantly superior efficacy.


Subject(s)
Aminolevulinic Acid/analogs & derivatives , Keratosis, Actinic/drug therapy , Photochemotherapy/methods , Photosensitizing Agents/administration & dosage , Aged , Aged, 80 and over , Aminolevulinic Acid/administration & dosage , Aminolevulinic Acid/adverse effects , Drug Therapy, Combination , Female , Follow-Up Studies , Humans , Long-Term Care , Male , Middle Aged , Photosensitizing Agents/adverse effects , Prospective Studies , Recurrence , Treatment Outcome
5.
Eur Biophys J ; 41(10): 915-29, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22660649

ABSTRACT

Biological membranes can be targets for compounds that either disrupt their barrier function or affect protein function via membrane-mediated processes. Biophysical studies on membrane-mimetic systems composed of membrane lipids have contributed substantially to our knowledge on the pertaining membrane physics and aid the development of membrane-specific drugs. Moreover, lipid membranes and, in particular, liposomes are convenient systems for drug delivery. We review some of our recent work that demonstrates the applicability of X-ray scattering to understanding the molecular mechanisms of drug-membrane interactions. In particular we focus on effects of anesthetics, sphingomyelinase, and antimicrobial peptides. We further discuss X-ray scattering as a quality-control tool for liposomal drug-delivery systems.


Subject(s)
Cell Membrane/drug effects , Lipid Bilayers/chemistry , Liposomes/chemistry , X-Ray Diffraction , Animals , Cell Membrane/chemistry , Drug Design , Humans , Membrane Proteins/chemistry
6.
Proc Natl Acad Sci U S A ; 109(17): 6394-8, 2012 Apr 24.
Article in English | MEDLINE | ID: mdl-22493218

ABSTRACT

Electrostatic self-assembly of colloidal and nanoparticles has attracted a lot of attention in recent years, since it offers the possibility of producing novel crystalline structures that have the potential to be used as advanced materials for photonic and other applications. The stoichiometry of these crystals is not constrained by charge neutrality of the two types of particles due to the presence of counterions, and hence a variety of three-dimensional structures have been observed depending on the relative sizes of the particles and their charge. Here we report structural polymorphism of two-dimensional crystals of oppositely charged linear macroions, namely DNA and self-assembled cylindrical micelles of cationic amphiphiles. Our system differs from those studied earlier in terms of the presence of a strongly binding counterion that competes with DNA to bind to the micelle. The presence of these counterions leads to novel structures of these crystals, such as a square lattice and a √3 x √3 superlattice of an underlying hexagonal lattice, determined from a detailed analysis of the small-angle diffraction data. These lower-dimensional equilibrium systems can play an important role in developing a deeper theoretical understanding of the stability of crystals of oppositely charged particles. Further, it should be possible to use the same design principles to fabricate structures on a longer length-scale by an appropriate choice of the two macroions.


Subject(s)
DNA/chemistry , Micelles , Nucleic Acid Conformation , Scattering, Small Angle , Static Electricity , X-Ray Diffraction
7.
Phys Chem Chem Phys ; 14(14): 4780-8, 2012 Apr 14.
Article in English | MEDLINE | ID: mdl-22395854

ABSTRACT

Losartan is an angiotensin II receptor antagonist mainly used for the regulation of high blood pressure. Since it was anticipated that losartan reaches the receptor site via membrane diffusion, the impact of losartan on model membranes has been investigated by small angle X-ray scattering. For this purpose 2-20 mol% losartan was incorporated into dimyristoyl-phosphatidylcholine (DMPC) and palmitoyl-oleoyl-phosphatidylcholine (POPC) bilayers and into their binary mixtures with cholesterol in the concentration range of 0 to 40 mol%. Effects of losartan on single component bilayers are alike. Partitioning of losartan into the membranes confers a negative charge to the lipid bilayers that causes the formation of unilamellar vesicles and a reduction of the bilayer thickness by 3-4%. Analysis of the structural data resulted in an estimate for the partial area of losartan, A(Los) ≈ 40 Å(2). In the presence of cholesterol, differences between the effects of losartan on POPC and DMPC are striking. Membrane condensation by cholesterol is retarded by losartan in POPC. This contrasts with DMPC, where an increase of the cholesterol content shifts the partitioning equilibrium of losartan towards the aqueous phase, such that losartan gets depleted from the bilayers from 20 mol% cholesterol onwards. This indicates (i) a chain-saturation dependent competition of losartan with lipid-cholesterol interactions, and (ii) the insolubility of losartan in the liquid ordered phase of PCs. Consequently, losartan's action is more likely to take place in fluid plasma membrane patches rather than in domains rich in cholesterol and saturated lipid species such as in membrane rafts.


Subject(s)
Cholesterol/chemistry , Lipid Bilayers/chemistry , Losartan/chemistry , Dimyristoylphosphatidylcholine/chemistry , Lipid Bilayers/metabolism , Losartan/metabolism , Membrane Microdomains/metabolism , Phosphatidylcholines/chemistry
8.
Biochim Biophys Acta ; 1808(6): 1753-63, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21315062

ABSTRACT

Valsartan is a marketed drug with high affinity to the type 1 angiotensin (AT1) receptor. It has been reported that AT1 antagonists may reach the receptor site by diffusion through the plasma membrane. For this reason we have applied a combination of differential scanning calorimetry (DSC), Raman spectroscopy and small and wide angle X-ray scattering (SAXS and WAXS) to investigate the interactions of valsartan with the model membrane of dipalmitoyl-phosphatidylcholine (DPPC). Hence, the thermal, dynamic and structural effects in bulk as well as local dynamic properties in the bilayers were studied with different valsartan concentrations ranging from 0 to 20 mol%. The DSC experimental results showed that valsartan causes a lowering and broadening of the phase transition. A splitting of the main transition is observed at high drug concentrations. In addition, valsartan causes an increase in enthalpy change of the main transition, which can be related to the induction of interdigitation of the lipid bilayers in the gel phase. Raman spectroscopy revealed distinct interactions between valsartan with the lipid interface localizing it in the polar head group region and in the upper part of the hydrophobic core. This localization of the drug molecule in the lipid bilayers supports the interdigitation view. SAXS measurements confirm a monotonous bilayer thinning in the fluid phase, associated with a steady increase of the root mean square fluctuation of the bilayers as the valsartan concentration is increased. At high drug concentrations these fluctuations are mainly governed by the electrostatic repulsion of neighboring membranes. Finally, valsartans' complex thermal and structural effects on DPPC bilayers are illustrated and discussed on a molecular level.


Subject(s)
1,2-Dipalmitoylphosphatidylcholine/chemistry , Lipid Bilayers/chemistry , Tetrazoles/chemistry , Valine/analogs & derivatives , 1,2-Dipalmitoylphosphatidylcholine/metabolism , Algorithms , Angiotensin II Type 1 Receptor Blockers/chemistry , Angiotensin II Type 1 Receptor Blockers/metabolism , Binding, Competitive , Calorimetry, Differential Scanning , Kinetics , Lipid Bilayers/metabolism , Models, Chemical , Models, Molecular , Molecular Structure , Scattering, Small Angle , Spectrum Analysis, Raman , Temperature , Tetrazoles/metabolism , Thermodynamics , Valine/chemistry , Valine/metabolism , Valsartan , X-Ray Diffraction
9.
Br J Dermatol ; 163(2): 386-94, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20518784

ABSTRACT

BACKGROUND: Photodynamic therapy (PDT) with 5-aminolaevulinic acid (ALA) provides a therapeutic option for the treatment of actinic keratosis (AK). Different strategies are applied to overcome the chemical instability of ALA in solution and to improve skin penetration. A new stable nanoemulsion-based ALA formulation, BF-200 ALA, is currently in clinical development for PDT of AK. OBJECTIVES: To evaluate the efficacy and safety of PDT of AK with BF-200 ALA. METHODS: The study was performed as a randomized, multicentre, double-blind, placebo-controlled, interindividual, two-armed trial with BF-200 ALA and placebo. A total of 122 patients with four to eight mild to moderate AK lesions on the face and/or the bald scalp were included in eight German study centres. The efficacy of BF-200 ALA after one and two PDT treatments was evaluated. BF-200 ALA was used in combination with two different light sources under illumination conditions defined by European competent authorities. RESULTS: PDT with BF-200 ALA was superior to placebo PDT with respect to patient complete clearance rate (per-protocol group: 64% vs. 11%; P < 0.0001) and lesion complete clearance rate (per-protocol group: 81% vs. 22%) after the last PDT treatment. Statistically significant differences in the patient and lesion complete clearance rates and adverse effect profiles were observed for the two light sources, Aktilite CL128 and PhotoDyn 750, at both time points of assessment. The patient and lesion complete clearance rates after illumination with the Aktilite CL128 were 96% and 99%, respectively. CONCLUSIONS: BF-200 ALA is a very effective new formulation for the treatment of AK with PDT. Marked differences between the efficacies and adverse effects were observed for the different light sources used. Thus, PDT efficacy is dependent both on the drug and on the characteristics of the light source and the illumination conditions used.


Subject(s)
Aminolevulinic Acid/therapeutic use , Keratosis, Actinic/drug therapy , Photochemotherapy/methods , Photosensitizing Agents/therapeutic use , Adolescent , Adult , Aged , Aged, 80 and over , Biopsy , Double-Blind Method , Female , Germany , Humans , Keratosis, Actinic/pathology , Male , Middle Aged , Prospective Studies , Young Adult
10.
Chem Phys Lipids ; 163(6): 460-79, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20361949

ABSTRACT

Scattering techniques, in particular electron, neutron and X-ray scattering have played a major role in elucidating the static and dynamic structure of biologically relevant membranes. Importantly, neutron and X-ray scattering have evolved to address new sample preparations that better mimic biological membranes. In this review, we will report on some of the latest model membrane results, and the neutron and X-ray techniques that were used to obtain them.


Subject(s)
Cell Membrane/chemistry , Models, Molecular , Neutron Diffraction , X-Ray Diffraction , Membrane Proteins/chemistry , Phospholipids/chemistry
11.
Rev Stomatol Chir Maxillofac ; 110(1): e1-4, 2009 Feb.
Article in French | MEDLINE | ID: mdl-19108856

ABSTRACT

INTRODUCTION: Sialendoscopy and sialo-MRI enable diagnosis of salivary gland obstructive pathologies, such as lithiasis, stenosis and dilatations. Therefore, a classification of these pathologies is needed, allowing large series comparisons, for better diagnosis and treatment of salivary pathologies. MATERIAL AND METHODS: With help from people from the European Sialendoscopy Training Center (ESTC), the results of sialographies, sialoMRI and sialendoscopies, a comprehensive classification of obstructive salivary pathologies is described, based on the absence or presence of lithiasis (L), stenosis (S) and dilatation (D) ("LSD" classification). DISCUSSION: It appears that a classification of salivary gland obstructive pathologies should be described. We hope it will be widely used and of course criticized to be improved and to compare the results of salivary gland diagnostic methods, such as sialography and sialendoscopy and also the results and indications for salivary gland therapeutic methods, such as lithotripsy, sialendoscopy and/or open surgery.


Subject(s)
Salivary Duct Calculi/classification , Salivary Gland Calculi/classification , Salivary Gland Diseases/classification , Constriction, Pathologic/classification , Dilatation, Pathologic/classification , Endoscopy , Humans , Magnetic Resonance Imaging , Salivary Ducts/pathology , Sialography
12.
Rev Stomatol Chir Maxillofac ; 109(4): 233-6, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18774150

ABSTRACT

INTRODUCTION: Sialendoscopy and sialoMRI enables diagnosis of salivary gland obstructive pathologies, such as lithiasis, stenosis, and dilatations. Therefore, a classification of these pathologies is needed, allowing large series comparisons, for better diagnosis and treatment of salivary pathologies. MATERIAL AND METHODS: With help from people from the European Sialendoscopy Training Center (ESTC), the results of sialographies, sialoMRI and sialendoscopies, a comprehensive classification of obstructive salivary pathologies is described, based on the absence or presence of lithiasis (L), stenosis (S), and dilatation (D) ("LSD" classification). DISCUSSION: It appears that a classification of salivary gland obstructive pathologies should be described. We hope it will be widely used and of course criticized to be improved and to compare the results of salivary gland diagnostic methods, such as sialography and sialendoscopy, and also the results and indications for salivary gland therapeutic methods, such as lithotripsy, sialendoscopy, and/or open surgery.


Subject(s)
Salivary Gland Calculi/classification , Salivary Gland Diseases/classification , Constriction, Pathologic/classification , Dilatation, Pathologic/classification , Endoscopy , Humans , Magnetic Resonance Imaging , Salivary Duct Calculi/classification , Salivary Ducts/pathology , Sialography
13.
Biophys J ; 94(12): 4688-99, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18326643

ABSTRACT

As the main difference between bacterial and mammalian cell membranes is their net charge, the focal point of consideration in many model membrane experiments with antimicrobial peptides is lipid headgroup charge. We studied the interaction of the human multifunctional peptide LL-37 with single phospholipid monolayers, bilayers, and bilayers composed of binary mixtures of the four phospholipid species predominantly used in model membrane experiments (phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylserine). We found that 1), the effects on single lipid monolayers are not comparable to those on the corresponding bilayers; 2), there are four different effects of LL-37 on bilayers of the four lipids; 3), the preference of LL-37 for the specific lipids is roughly inversely related to chain packing density; and 4), in the binary lipid mixtures, one lipid-and not necessarily the charged one--generally governs the mode of lipid/peptide interaction. Thus, our results show that lipid net charge is not the decisive factor determining the membrane-perturbing mechanism of LL-37, but only one of several parameters, among them packing density, the ability to form intermolecular H-bonds, and lipid molecular shape, which emphasizes how profoundly the choice of the model system can influence the outcome of a study of lipid/peptide interaction.


Subject(s)
Lipid Bilayers/chemistry , Liposomes/chemistry , Membrane Lipids/chemistry , Models, Chemical , Models, Molecular , Computer Simulation , Molecular Conformation
14.
Biochim Biophys Acta ; 1768(10): 2586-95, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17662236

ABSTRACT

The human, multifunctional peptide LL-37 causes membrane disruption by distinctly different mechanisms strongly dependent on the nature of the membrane lipid composition, varying not only with lipid headgroup charge but also with hydrocarbon chain length. Specifically, LL-37 induces a peptide-associated quasi-interdigitated phase in negatively charged phosphatidylglycerol (PG) model membranes, where the hydrocarbon chains are shielded from water by the peptide. In turn, LL-37 leads to a disintegration of the lamellar organization of zwitterionic dipalmitoyl-phosphatidylcholine (DPPC) into disk-like micelles. Interestingly, interdigitation was also observed for the longer-chain C18 and C20 PCs. This dual behavior of LL-37 can be attributed to a balance between electrostatic interactions reflected in different penetration depths of the peptide and hydrocarbon chain length. Thus, our observations indicate that there is a tight coupling between the peptide properties and those of the lipid bilayer, which needs to be considered in studies of lipid/peptide interaction. Very similar effects were also observed for melittin and the frog skin peptide PGLa. Therefore, we propose a phase diagram showing different lipid/peptide arrangements as a function of hydrocarbon chain length and LL-37 concentration and suggest that this phase diagram is generally applicable to membrane-active peptides localized parallel to the membrane surface.


Subject(s)
Antimicrobial Cationic Peptides/pharmacology , Cell Membrane/drug effects , Membrane Lipids/chemistry , Androstanes/chemistry , Calorimetry, Differential Scanning , Electron Spin Resonance Spectroscopy , Lipid Bilayers/chemistry , Microscopy, Electron , Phosphatidylglycerols , Scattering, Radiation , Cathelicidins
15.
Eur J Ophthalmol ; 15(5): 598-606, 2005.
Article in English | MEDLINE | ID: mdl-16167290

ABSTRACT

PURPOSE: To investigate whether topical nonsteroidal antiinflammatory drugs (NSAIDs) are useful, in the absence of concomitant corticosteroid therapy, in limiting postoperative inflammation after uncomplicated cataract surgery. METHODS: A total of 328 patients were enrolled in a prospective, randomized, double-masked, parallel-group, active-controlled study. Anterior chamber inflammation (ACI) was evaluated as the primary efficacy parameter. Only patients with moderate inflammation (ACI score of < or =4) the day after surgery were randomized and treated with NSAIDs. A novel topical formulation containing 0.2% sodium naproxen was compared with 0.1% diclofenac. Both were administered three times a day for 14 consecutive days. Ocular inflammation was measured after 7 and 14 days by using slit-lamp biomicroscopy. Safety parameters were also evaluated at the same time. RESULTS: Both treatments were equally effective in controlling postsurgical inflammation. No statistically significant differences between treatment groups were observed for the safety variables. No serious adverse events (AEs) occurred during the course of the study. The most frequent AE reported with naproxen was eye redness. CONCLUSIONS: NSAIDs can effectively be used without concurrent administration of corticosteroids to control postoperative inflammation after uncomplicated cataract surgery. In addition, naproxen ophthalmic solution may be considered a suitable alternative to the currently available NSAIDs.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Diclofenac/administration & dosage , Naproxen/administration & dosage , Phacoemulsification , Postoperative Complications/prevention & control , Uveitis, Anterior/prevention & control , Administration, Topical , Adult , Aged , Aged, 80 and over , Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Diclofenac/adverse effects , Double-Blind Method , Female , Humans , Inflammation/prevention & control , Lens Implantation, Intraocular , Male , Middle Aged , Naproxen/adverse effects , Prospective Studies , Treatment Outcome
16.
Biochim Biophys Acta ; 1716(1): 40-8, 2005 Oct 01.
Article in English | MEDLINE | ID: mdl-16150420

ABSTRACT

We have determined the mixing properties and lamellar organization of bacterial membrane mimetics composed of 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) and -phosphatidylglycerol (POPG) at various molar ratios applying differential scanning calorimetry, small and wide-angle X-ray scattering, as well as optical phase contrast microscopy. Combining the experimental thermodynamic data with a simulation of the liquidus and solidus lines, we were able to construct a phase diagram. Using this approach, we find that the lipids mix in all phases non-ideally in the thermodynamic sense. As expected, pure POPE assembles into multilamellar and pure POPG into unilamellar vesicles, respectively, which are stable within the studied temperature range. In contrast, mixtures of the two components form oligolamellar vesicles consisting of about three to five bilayers. The layers within these oligolamellar liposomes are positionally correlated within the gel phase, but become uncorrelated within the fluid phase exhibiting freely fluctuating bilayers, while the vesicles as a whole remain intact and do not break up into unilamellar forms. X-ray, as well as DSC data, respectively, reveal a miscibility gap due to a lateral phase segregation at POPG concentrations above about 70 mol%, similar to previously reported data on mixtures composed of disaturated PEs and PGs. Hence, the existence of a region of immiscibility is a general feature of PE/PG mixtures and the mixing properties are dominated by PE/PG headgroup interactions, but are largely independent of the composition of the hydrocarbon chains. This is in accordance with a recent theoretical prediction.


Subject(s)
Bacteria/metabolism , Cell Membrane/metabolism , Biophysical Phenomena , Biophysics , Calorimetry, Differential Scanning , Escherichia coli/metabolism , Hydrocarbons/chemistry , Lipids/chemistry , Liposomes/chemistry , Microscopy, Confocal , Microscopy, Phase-Contrast , Models, Chemical , Phosphatidylethanolamines/chemistry , Phosphatidylglycerols/chemistry , Scattering, Radiation , Staphylococcus aureus/metabolism , Temperature , Thermodynamics , X-Ray Diffraction , X-Rays
17.
Eur J Ophthalmol ; 15(5): 598-606, 2005.
Article in English | MEDLINE | ID: mdl-28221461

ABSTRACT

PURPOSE: To investigate whether topical nonsteroidal antiinflammatory drugs (NSAIDs) are useful, in the absence of concomitant corticosteroid therapy, in limiting postoperative inflammation after uncomplicated cataract surgery. METHODS: A total of 328 patients were enrolled in a prospective, randomized, double-masked, parallel-group, active-controlled study. Anterior chamber inflammation (ACI) was evaluated as the primary efficacy parameter. Only patients with moderate inflammation (ACI score of <=4) the day after surgery were randomized and treated with NSAIDs. A novel topical formulation containing 0.2% sodium naproxen was compared with 0.1% diclofenac. Both were administered three times a day for 14 consecutive days. Ocular inflammation was measured after 7 and 14 days by using slit-lamp biomicroscopy. Safety parameters were also evaluated at the same time. RESULTS: Both treatments were equally effective in controlling postsurgical inflammation. No statistically significant differences between treatment groups were observed for the safety variables. No serious adverse events (AEs) occurred during the course of the study. The most frequent AE reported with naproxen was eye redness. CONCLUSIONS: NSAIDs can effectively be used without concurrent administration of corticosteroids to control postoperative inflammation after uncomplicated cataract surgery. In addition, naproxen ophthalmic solution may be considered a suitable alternative to the currently available NSAIDs. (Eur J Ophthalmol 2005; 15: 598-606).

18.
Phys Rev E Stat Nonlin Soft Matter Phys ; 70(2 Pt 1): 021908, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15447516

ABSTRACT

We have determined the structural properties and bending fluctuations of fully hydrated phosphatidylcholine multibilayers in the fluid (Lalpha) phase, as well as the structure of the ripple (Pbeta') phase near the main phase transition temperature (TM) by x-ray diffraction. The number of carbons, nHC, per acyl chain of the studied disaturated lipids varied from 14 to 22. All lipids exhibit a nonlinear increase of the lamellar repeat distance d in the Lalpha phase upon approaching TM, known as "anomalous swelling." The nonlinear increase reduces with chain length, but levels off at a constant value of about 0.5 A for lipids with more than 18 hydrocarbons per chain. A detailed analysis shows that anomalous swelling has two components. One is due to an expansion of the water layer, which decreases with chain length and finally vanishes for nHC >18. The second component is due to a bilayer thickness increase, which remains unchanged in its temperature dependence, including a nonlinear component of about 0.5 A in the vicinity of TM. Thus, anomalous swelling above 18 hydrocarbons per chain is due to the pretransitional effects on the membrane only. These results are supported by a bending fluctuation analysis revealing increased undulations close to TM only for the short chain lipids. We have further calculated the electron density maps in the ripple phase and find no coupling of the magnitude of the ripple amplitude to the chain length effects observed in the Lalpha phase. Hence, in agreement with an earlier report by Mason et al. [Phys. Rev. E 63, 030902 (2001)] there is no connection between the formation of the ripple phase and anomalous swelling.


Subject(s)
Biophysics/methods , Phosphatidylcholines/chemistry , Carbon/chemistry , Hydrocarbons/chemistry , Lipid Bilayers/chemistry , Lipids/chemistry , Models, Statistical , Temperature , Water , X-Ray Diffraction
19.
Phys Rev E Stat Nonlin Soft Matter Phys ; 69(3 Pt 1): 031906, 2004 Mar.
Article in English | MEDLINE | ID: mdl-15089321

ABSTRACT

Using neutron diffraction and a specially constructed high pressure cell suitable for aligned multibilayer systems, we have studied, as a function of pressure, the much observed anomalous swelling regime in dimyristoyl- and dilauroyl-phosphatidylcholine bilayers, DMPC and DLPC, respectively. We have also reanalyzed data from a number of previously published experiments and have arrived at the following conclusions. (a). The power law behavior describing anomalous swelling is preserved in all PC bilayers up to a hydrostatic pressure of 240 MPa. (b). As a function of increasing pressure there is a concomitant decrease in the anomalous swelling of DMPC bilayers. (c). For PC lipids with hydrocarbon chains >or=13 carbons the theoretical unbinding transition temperature T small star, filled is coupled to the main gel-to-liquid crystalline transition temperature T(M). (d). DLPC is intrinsically different from the other lipids studied in that its T small star, filled is not coupled to T(M). (e). For DLPC bilayers we predict a hydrostatic pressure (>290 MPa) where unbinding may occur.


Subject(s)
Dimyristoylphosphatidylcholine/chemistry , Lipid Bilayers/chemistry , Membrane Fluidity , Neutron Diffraction/methods , Phosphatidylcholines/chemistry , Binding Sites , Gels/chemistry , Hydrostatic Pressure , Membranes, Artificial , Molecular Conformation , Phase Transition , Phospholipids/chemistry , Solutions , Transition Temperature
20.
J Clin Pharmacol ; 43(11): 1244-56, 2003 Nov.
Article in English | MEDLINE | ID: mdl-14551179

ABSTRACT

Ragaglitazar is a novel dual peroxisome proliferator-activated receptor (PPAR) alpha and gamma agonist intended to restore insulin sensitivity and correct diabetic dyslipidemia. These studies assessed single-dose pharmacokinetics and tolerability of ragaglitazar in healthy subjects, as well as multiple-dose pharmacokinetics, pharmacodynamics, and tolerability of ragaglitazar in healthy subjects and in patients with type 2 diabetes. Healthy subjects received a single oral dose (1-120 mg), and healthy subjects and type 2 diabetic patients received a loading dose and thereafter once-daily doses (0.5-16 mg) of ragaglitazar for 6 and 20 days, respectively. Ragaglitazar was rapidly absorbed (tmax: 1.5-1.7 h), with mean AUC0-24 h and Cmax proportional to dose after single and multiple dosing; t1/2 was 80 hours following a single dose and 104 hours in healthy subjects and 122 hours in patients after multiple dosing. Administration of 4 mg ragaglitazar to patients (n = 4) for 21 days resulted in mean decreases from baseline in fasting levels of plasma glucose (18%), C-peptide (18%), fructosamine (6%), triglycerides (36%), free fatty acids (49%), total cholesterol (11%), low-density lipoprotein (LDL) cholesterol (21%), and very low-density lipoprotein (VLDL) cholesterol (15%), as well as an increase in high-density lipoprotein (HDL) cholesterol (33%). Overall, ragaglitazar was well tolerated; with multiple dosing, there was a higher incidence of adverse events for patients that, at the highest dose level (16 mg), included peripheral edema and anemia.


Subject(s)
Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/drug therapy , Oxazines/pharmacology , Oxazines/pharmacokinetics , Phenylpropionates/pharmacology , Phenylpropionates/pharmacokinetics , Receptors, Cytoplasmic and Nuclear/agonists , Transcription Factors/agonists , Adolescent , Adult , Aged , Area Under Curve , Confidence Intervals , Dose-Response Relationship, Drug , Double-Blind Method , Humans , Linear Models , Male , Middle Aged , Oxazines/adverse effects , Phenylpropionates/adverse effects
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