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Lipid Phase (lipid + phase)
Selected AbstractsLiposomes for entrapping local anesthetics: A liposome electrokinetic chromatographic studyELECTROPHORESIS, Issue 9 2010Jana Lokajová Abstract Bupivacaine is a lipophilic, long-acting, amide class local anesthetic commonly used in clinical practice to provide local anesthesia during surgical procedures. Several cases of accidental overdose with cardiac arrest and death have been reported since bupivacaine was introduced to human use. Recent case reports have suggested that Intralipid (Fresenius Kabi) is an effective therapy for cardiac toxicity from high systemic concentrations of, e.g. bupivacaine, even though the mechanism behind the interaction is not fully clear yet. Our long-term aim is to develop a sensitive, efficient, and non-harmful lipid-based formulation to specifically trap harmful substances in vivo. In this study, the in vitro interaction of local anesthetics (bupivacaine, prilocaine, and lidocaine) with Intralipid or lipid vesicles containing phosphatidylglycerol, phosphatidylcholine, cardiolipin, cholesterol, and N -palmitoyl- D - erythro -sphingosine (ceramide) was determined by liposome electrokinetic chromatography. The interactions were evaluated by calculating the retention factors and distribution constants. Atomic force microscopy measurements were carried out to confirm that the interaction mechanism was solely due to interactions between the analytes and the moving pseudostationary phase and not by interactions with a stationary lipid phase adsorbed to the fused-silica wall. The heterogeneity of the liposomes was also studied by atomic force microscopy. The liposome electrokinetic chromatography results demonstrate that there is higher interaction between the drugs and negatively charged liposome dispersion than with the commercial Intralipid dispersion. [source] Interaction of the alpha-helical H6 peptide from the pro-apoptotic protein tBid with cardiolipinFEBS JOURNAL, Issue 21 2009Patrice X. Petit BH3 interacting domain death agonist (Bid), a pro-apoptotic member of the Bcl-2 family of proteins, is activated through cleavage by caspase-8. The active C-terminal fragment of Bid (tBid) translocates to the mitochondria where it interacts with cardiolipins at contact sites and induces the release of cytochrome c by a mechanism that is not yet fully understood. It has been shown that the alpha-helices ,H6 and ,H7 (which create the hairpin-forming domain of tBid) mediate the insertion of Bid into mitochondrial membranes and are essential for the cytochrome c -releasing activity. In the present study, we focused on the interaction between the ,H6 and the mitochondrial membrane. By the use of single-cell electropermeabilization associated with flow cytometric analysis of intact cells, we demonstrated that H6 is able to induce cell death when used in the micromolar range. We also studied the interactions of the ,H6 with artificial monolayers. We showed that the presence of negatively charged cardiolipins greatly enhances the insertion of ,H6 into the phospholipid monolayer. The modification of two charged amino acid residues in ,H6 abolished its insertion and also its in vivo effects. Furthermore, the negative values of the excess areas of mixing indicate that attractive interactions between cardiolipins and ,H6 occur in the mixed monolayers. Fluorescence microscopy observations revealed that ,H6 significantly disrupts cardiolipin packing and stabilizes the fluid lipid phase. These results suggest that cardiolipins at the contact sites between the two mitochondrial membranes could mediate the binding of tBid via ,H6. [source] Effect of oil content and processing conditions on the thermal behaviour and physicochemical stability of oil-in-water emulsionsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2009Megan Tippetts Summary The destabilisation mechanism of oil-in-water (o/w) emulsions was studied as a function of oil content (20% and 40% o/w), homogenisation conditions and crystallisation temperatures (10, 5, 0, ,5 and ,10 °C). A mixture of anhydrous milk fat and soya bean oil was used as the lipid phase and whey protein isolate (2 wt%) as emulsifier. Crystallisation and melting behaviours were analysed using differential scanning calorimetry. Physicochemical stability was measured with a vertical scan macroscopic analyser. Emulsions with 20% oil were found to be less stable than those with 40% oil. For 20% o/w emulsions, the crystallisation was delayed and inhibited in emulsions with smaller droplets and promoted in emulsions with larger droplets when compared with 40% o/w emulsions. Depending on the droplet sizes in the emulsion, the formation of lipid crystals (in combination with the emulsifier) either stabilises (small droplets) or destabilises (big droplets) the emulsion. [source] A two-phase analysis of solute partitioning into the stratum corneumJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2006Johannes M. Nitsche Abstract An analysis is presented of partition coefficients KSC/w describing solute distribution into fully hydrated stratum corneum (SC) from dilute aqueous solution (w). A comprehensive database is compiled from the experimental literature covering more than eight decades in the octanol/water partition coefficient Ko/w. It is analyzed according to a two-phase model following that of Anderson, Raykar, and coworkers (1988, 1989), which accounts for uptake by intercellular lipid and corneocyte (keratin plus water) phases having inherently different lipophilicities, as characterized by an SC lipid/water partition coefficient Klip/w and a partition coefficient PCpro/w quantifying cornoeocyte-phase binding. Regression of 72 data points yields useful best-fit recalibrations of power laws (or linear free energy relationships) giving Klip/w and PCpro/w as functions of Ko/w. The specific conclusions of the analysis are as follows: (i) The two-phase model offers substantial improvements over previously proposed analytical representations of KSC/w, yielding an rms error in log10KSC/w of 0.30 limited by the scatter in the data. (ii) The best-fit description of the lipid phase is given by the power law Klip/w,=,0.43 (Ko/w)0.81, suggesting about half the absolute value of Klip/w relative to previous estimates. (iii) The best-fit description of corneocyte-phase binding differs negligibly from the correlation found by Anderson, Raykar, and coworkers for the more limited set of compounds studied by them. Explicit consideration of the two-phase nature of the SC also furnishes a rational basis for predicting the effects of varying hydration state upon KSC/w. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:649,666, 2006 [source] Multidrug resistance modulator interactions with neutral and anionic liposomes: membrane binding affinity and membrane perturbing activityJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 5 2005Madeleine Castaing A variety of cationic lipophilic compounds (modulators) have been found to reverse the multidrug resistance of cancer cells. In order to determine the membrane perturbing efficacy and the binding affinity of such drugs in neutral and anionic liposomes, the leakage of Sulfan blue induced by five modulators bearing different electric charges was quantified using liposomes with and without phosphatidic acid (xEPA = 0 and 0.1), at four lipid concentrations. The binding isotherms were drawn up using the indirect method based on the dependency of the leakage rate on the modulator and the lipid concentrations. Upon inclusion of negatively charged lipids in the liposomes: (i) the binding of cationic drugs was favoured, except in a case where modulator aggregation occurred in the lipid phase; (ii) the drugs with a net electric charge greater than 1.1 displayed a greater enhancement in their potency to produce membrane perturbation; and (iii) the EPA effect on membrane permeation was due mainly to that on membrane perturbation (,50%) and, to a lesser extent, to that on the binding affinity (,50%). The present study provides evidence that drug-membrane interactions are the result of a complex interplay between the structural and electrical characteristics of the drugs and those of the membranes. [source] In-vitro release of bupivacaine from injectable lipid formulations investigated by a single drop technique , relation to duration of action in-vivoJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2002Lars Söderberg The aim of this study was to develop an in-vitro release method suitable for injectable slow-release lipid formulations of local anaesthetics (or other drugs). We also aimed that the results of the in-vitro measurements should have a clear relationship to duration of action in-vivo. Six formulations of bupivacaine base in medium-chain triglyceride-glyceryl dilaurate mixtures were developed. A new apparatus was constructed for determination of their in-vitro release profiles. A bulbous glass tube was fixed inside a standard glass bottle, which was then filled with release medium. A stirring magnet was enclosed in the perforated polypropylene cylinder holding the glass tube. The stirring created a continuous, rotating downward flow of medium inside the tube, which kept the lipid phase, introduced by means of a syringe, suspended as a single, free drop. Release profiles were obtained by sampling of the release medium for up to 72 h and analysis by gas-liquid chromatography. The duration of action in-vivo of the respective formulations was tested by the hot-plate method in rats. The release profiles of bupivacaine in-vitro were mono-exponential for four formulations and bi-exponential for the other two. There was a positive correlation between the proportion of glyceryl dilaurate in the formulation and the slow half-life of release of bupivacaine. All formulations showed prolonged duration of action in-vivo, median values within the range 4.5,12 h, as compared with a 2-h effect of bupivacaine hydrochloride solution. A comparison of in-vitro release curves and durations of action in-vivo suggested that to maintain nerve blockade in-vivo the formulations must release bupivacaine at a rate of approximately 350 ,g h,1 under the in-vitro conditions. To conclude, we designed and tested a novel apparatus for measuring release of a local anaesthetic (or other drug) from a fluid or semi-solid formulation in-vitro. Release rates obtained in-vitro by means of this technique may be used to guide the development of formulations with suitable durations of action in-vivo. The apparatus is, however, as yet a prototype. Rigorous evaluation of performance should be carried out on devices built to specific standards according to their intended application. [source] Quantification of the water/lipid affinity of melatonin and a pinoline derivative in lipid modelsJOURNAL OF PINEAL RESEARCH, Issue 4 2007Jamila Mekhloufi Abstract:, This study assessed the location of melatonin (N-acetyl-5-methoxytryptamine) and of a pinoline derivative (GWC22) [6-ethyl-1-(3-methoxyphenyl)-2-propyl-1,2,3,4-tetrahydro-beta-carboline], when present in lipid assemblies such as linoleate micelles, phosphatidylcholine liposomes or low density lipoproteins (LDL). The efficiency of radical scavenging by these compounds is highly dependent on their partitioning between the lipidic and aqueous phases. We determined the proportion of melatonin or GWC22 in the aqueous and lipid phases of each system (concentrations of the antioxidants ranging between 3 × 10,5 and 10,4 m) by assaying melatonin or GWC22 by HPLC/UV detection, or by fluorescence for melatonin in micelles. Our results show that melatonin and GWC22 were preferentially located in the aqueous phase of micelles (68.4% and 59.0%, respectively), whereas only 30.5% of melatonin and 39.0% of GWC22 were found in the lipid phase. By contrast, in phosphatidylcholine liposomes, both compounds were essentially present in the lipid phase (73.5% for melatonin and 79.1% for GWC22, versus 25.9% and 19.5% in the aqueous phase, respectively). In the case of LDL, 99.9% of the melatonin added was found in the methanol/water extracting phase containing phospholipids, unesterified cholesterol and apolipoprotein B100. The partitioning of melatonin and GWC22 in linoleate micelles gave new insights on the marked protective effect of GWC22 towards radiation-induced lipid peroxidation and allowed us to determine more accurately the lower limit values of the reaction rate constants of the two molecules studied with lipid peroxyl radicals, i.e. k(LOO,+melatonin) , 9.0 × 104m,1s,1 and k(LOO,+GWC22) , 3.5 × 105m,1s,1. [source] Improvement of ,-tocopherols long-term efficiency by modeling its heterogeneous natural environment in polyethyleneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2006Clara Strandberg Abstract The natural antioxidant vitamin E (,-tocopherol) is of interest to use in packaging applications to decrease the amount of toxic products migrating into food and drugs. We have earlier shown that the long-term efficiency of ,-tocopherol in polyethylene (PE) films is poor. ,-Tocopherol is located in the lipid phase of the cell in vivo and it has been revealed that it is more efficient in a polar substrate. PE is more hydrophobic and homogenous than the heterogeneous and hydrophilic lipid phase. Three different additive systems were investigated to model ,-tocopherols heterogeneous natural environment in PE. Two of these had carboxylic acid groups, EAA and polyTRIM/PAA core-shell particles (Core), and the third, oat starch, had no carboxylic acid groups. The materials were thermally aged and characterized by chemiluminescence (CL), FTIR, chromatography, and thermal analysis. The EAA system as well as the Core system improved the antioxidant properties of ,-tocopherol in PE, and the Core system had the best performance. We know that starch has stabilizing properties in PE, but it had no effect on the efficiency of ,-tocopherol. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1660,1666, 2006 [source] Influence of composition and structure of oil-in-water emulsions on retention of aroma compoundsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2002Dr Saskia M van Ruth Abstract The influence of the composition and structure of oil-in-water emulsions on aroma retention was examined for 20 volatile compounds. Compositional and structural parameters included the fraction of emulsifier phase, the fraction of lipid phase and the particle size distribution of the dispersed lipid phase in the emulsion. Air/liquid partition coefficients of dimethyl sulphide, 1-propanol, diacetyl, 2-butanone, ethyl acetate, 1-butanol, 2-pentanol, propyl acetate, 3-methyl-1-butanol, ethyl butyrate, hexanal, butyl acetate, 1-hexanol, 2-heptanone, heptanal, ,-pinene, 2-octanone, octanal, 2-nonanol and 2-decanone were determined by static headspace gas chromatography. The hydrophobicity of the compounds determined the influence of the compositional and structural parameters of the emulsions on air/liquid partitioning. Increase of the emulsifier fraction increased the retention of mainly hydrophilic aroma compounds and decreased the retention of hydrophobic compounds. Higher lipid levels led to increased retention of hydrophobic compounds and release of hydrophilic compounds. Emulsions with larger particles showed increased aroma retention, which was independent of the lipid fraction and the polarity of the aroma compounds. The data demonstrated a profound effect of both composition and structure of oil-in-water emulsions on the air/liquid partitioning of the 20 aroma compounds under equilibrium conditions. © 2002 Society of Chemical Industry [source] Liposome/water lipophilicity: Methods, information content, and pharmaceutical applicationsMEDICINAL RESEARCH REVIEWS, Issue 3 2004Georgette Plemper van Balen Abstract This review discusses liposome/water lipophilicity in terms of the structure of liposomes, experimental methods, and information content. In a first part, the structural properties of the hydrophobic core and polar surface of liposomes are examined in the light of potential interactions with solute molecules. Particular emphasis is placed on the physicochemical properties of polar headgroups of lipids in liposomes. A second part is dedicated to three useful methods to study liposome/water partitioning, namely potentiometry, equilibrium dialysis, and 1H-NMR relaxation rates. In each case, the principle and limitations of the method are discussed. The next part presents the structural information encoded in liposome/water lipophilicity, in other words the solutes' structural and physicochemical properties that determine their behavior and hence their partitioning in such systems. This presentation is based on a comparison between isotropic (i.e., solvent/water) and anisotropic (e.g., liposome/water) systems. An important factor to be considered is whether the anisotropic lipid phase is ionized or not. Three examples taken from the authors' laboratories are discussed to illustrate the factors or combinations thereof that govern liposome/water lipophilicity, namely (a) hydrophobic interactions alone, (b) hydrophobic and polar interactions, and (c) conformational effects plus hydrophobic and ionic interactions. The next part presents two studies taken from the field of QSAR to exemplify the use of liposome/water lipophilicity in structure,disposition and structure,activity relationships. In the conclusion, we summarize the interests and limitations of this technology and point to promising developments. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 3, 299,324, 2004 [source] The effect of phenyltin chlorides on osmotically induced erythrocyte haemolysisAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 6 2005Adam Miszta Abstract The toxicity of many amphiphilic compounds may result from their effect on the lipid phase of biological membranes. Upon incorporation such compounds may change the properties of membranes in general and in particular alter the organization of membrane lipids. These changes should affect, among other things, the mechanical properties of membranes. We selected two amphiphilic compounds, diphenyltin dichloride (Ph2SnCl2) and triphenyltin chloride (Ph3SnCl), which are known to be located at different regions of the lipid bilayer and to be toxic. As a model biological membrane the erythrocyte plasma membrane was used. Analysis of the haemolysis kinetics showed differences between the effect of the compound studied on mechanical properties at so-called non-lytic concentrations. Diphenyltin dichloride showed a limited effect on erythrocyte haemolysis, whereas triphenyltin chloride affected all the parameters measured (extent of initial haemolysis, extent of final haemolysis and membrane mechanical strength). We correlated these effects with the location of the investigated compounds in liposomes. The presented data show that triphenyltin chloride reduces the erythrocyte plasma membrane mechanical strength and increases the extent of haemolysis under osmotic stress conditions. Copyright © 2005 John Wiley & Sons, Ltd. [source] Correlation of Plasma and Peritoneal Diasylate Clomipramine Concentration with Hemodynamic Recovery after Intralipid Infusion in RabbitsACADEMIC EMERGENCY MEDICINE, Issue 2 2009MBChB, Martyn Harvey FACEM Abstract Objectives:, Drug sequestration to an expanded plasma lipid phase has been proposed as a potential mechanism of action for lipid emulsions in lipophilic cardiotoxin overdose. The authors set out to document plasma and peritoneal diasylate clomipramine concentration after resuscitation with lipid emulsion in a rabbit model of clomipramine-induced hypotension. Methods:, Twenty sedated mechanically ventilated New Zealand White rabbits were allocated to receive either 12 mL/kg 20% Intralipid or 12 mL/kg saline solution, following clomipramine infusion to 50% baseline mean arterial pressure (MAP). Hemodynamic parameters and serum clomipramine concentration were determined to 59 minutes. Peritoneal dialysis with 20% Intralipid or saline solution was evaluated for clomipramine concentration. Results:, Mean arterial pressure was greater in lipid-treated animals as assessed by repeated-measures analysis of variance (F[1,14] = 6.84; p = 0.020). Lipid infusion was associated with elevated plasma clomipramine concentration and reduced initial volume of distribution (Vd; 5.7 [±1.6] L/kg lipid vs. 15.9 [±7.2] L/kg saline; p = 0.0001). Peritoneal diasylate clomipramine concentration was greater in lipid-treated animals (366.2 [±186.2] ,g/L lipid vs. 37.7 [±13.8] ,g/L saline; p = 0.002). Conclusions:, Amelioration of clomipramine-induced hypotension with lipid infusion is associated with reduced initial Vd and elevated plasma clomipramine concentration consistent with intravascular drug,lipid sequestration. Concomitant peritoneal dialysis with lipid emulsion enhances clomipramine extraction. [source] Thermotropic Lipid Phase Transition and the Behavior of Hydrolytic Enzymes in the Kidney Cortex Brush Border MembraneCHEMISTRY & BIODIVERSITY, Issue 10 2006Sankar Abstract Functional interactions of lipids and proteins were examined in brush-border membranes isolated from the kidney cortex by studying the temperature dependence of the hydrolytic enzyme activities. A close relationship was observed for the membrane proteins and the thermotropic lipid phase transitions. Three lines of evidences were provided for such dependence: a) Arrhenius relationship of the membrane-bound enzyme activities, and the effect of temperature in native and partially delipidated membranes, b) differential scanning calorimetric study of the membrane lipid phase transitions in the native and delipidated membranes, multilamellar vesicles prepared from the membrane extracted lipids, and in vesicles from dimyristoyl phosphatidylcholine, and c) the excimer (dimer)-formation studies of the membrane extrinsic fluorescent probe, pyrene, and the resultant membrane microviscosity. The brush-border membranes were partially delipidated with BuOH and 2,2,2-trifluoroethanol. The functional interactions of the delipidated membranes, which were greatly lost on lipid removal, were largely restored by the addition of exogenous lipids in the reconstitution process, which indicate the critical dependence of the membrane integral proteins on the neighboring lipid molecules in the bulk lipid phase. [source] FACTORS AFFECTING LIPID OXIDATION IN BREAST AND THIGH MUSCLE FROM CHICKEN, TURKEY AND DUCKJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2010Y. GONG ABSTRACT Lipid oxidation occurred rapidly in turkey muscle, intermediate in duck and slowest in chicken. pH was lowest in turkey muscle. Chicken muscle had a lower content of polyunsaturated fatty acids compared with turkey and duck muscles. The aqueous fraction of duck breast inhibited hemoglobin-mediated lipid oxidation in washed muscle more effectively than aqueous fractions from turkey and chicken muscle. ,-Tocopherol content was highest in duck muscle, intermediate in chicken and lowest in turkey. Depletion of tocopherols during frozen storage was more rapid in turkey and duck compared with chicken. It was thought that the elevated tocopherol level in chicken muscle may be caused by less efficient catabolism via the omega hydroxylation pathway. However, tocopherol hydroxylase activity was similar in chicken compared with turkey liver microsomes. Heme pigment content was around sixfold higher in duck breast compared with chicken and turkey breast. Duck thigh had especially elevated pH. PRACTICAL APPLICATIONS This work describes a number of factors that explain the wide variation in oxidative stability (chicken > duck > turkey) when comparing muscle tissues from the three avian species. These factors include muscle pH, concentration of heme pigments, fatty acid unsaturation, inhibitors of lipid oxidation in the aqueous fraction of the muscle, tocopherol content in lipid phases and depletion rates of tocopherol. These factors should be considered when developing strategies to inhibit lipid oxidation in muscle foods. The relatively high content of ,-tocopherol in chicken muscle compared with turkey should be a subject of further research to better understand the mechanisms by which certain animal species preferentially deposit the molecule into muscle. [source] Quantification of the water/lipid affinity of melatonin and a pinoline derivative in lipid modelsJOURNAL OF PINEAL RESEARCH, Issue 4 2007Jamila Mekhloufi Abstract:, This study assessed the location of melatonin (N-acetyl-5-methoxytryptamine) and of a pinoline derivative (GWC22) [6-ethyl-1-(3-methoxyphenyl)-2-propyl-1,2,3,4-tetrahydro-beta-carboline], when present in lipid assemblies such as linoleate micelles, phosphatidylcholine liposomes or low density lipoproteins (LDL). The efficiency of radical scavenging by these compounds is highly dependent on their partitioning between the lipidic and aqueous phases. We determined the proportion of melatonin or GWC22 in the aqueous and lipid phases of each system (concentrations of the antioxidants ranging between 3 × 10,5 and 10,4 m) by assaying melatonin or GWC22 by HPLC/UV detection, or by fluorescence for melatonin in micelles. Our results show that melatonin and GWC22 were preferentially located in the aqueous phase of micelles (68.4% and 59.0%, respectively), whereas only 30.5% of melatonin and 39.0% of GWC22 were found in the lipid phase. By contrast, in phosphatidylcholine liposomes, both compounds were essentially present in the lipid phase (73.5% for melatonin and 79.1% for GWC22, versus 25.9% and 19.5% in the aqueous phase, respectively). In the case of LDL, 99.9% of the melatonin added was found in the methanol/water extracting phase containing phospholipids, unesterified cholesterol and apolipoprotein B100. The partitioning of melatonin and GWC22 in linoleate micelles gave new insights on the marked protective effect of GWC22 towards radiation-induced lipid peroxidation and allowed us to determine more accurately the lower limit values of the reaction rate constants of the two molecules studied with lipid peroxyl radicals, i.e. k(LOO,+melatonin) , 9.0 × 104m,1s,1 and k(LOO,+GWC22) , 3.5 × 105m,1s,1. [source] High gas pressure effects on yeastBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2008V. Espinasse Abstract Dried microorganisms are particularly resistant to high hydrostatic pressure effects. However, exposure to high pressures of nitrogen proved to be effective in inactivating dried yeasts. In this study, we tried to elucidate this mechanism on Saccharomyces cerevisiae. High-pressure treatments were performed using different inert gases at 150 MPa and 25°C with holding time values up to 12 months. The influence of cell hydration was also investigated. For fully hydrated cells, pressurized gases had little specific effect: cell inactivation was mainly due to compression effects. However, dried cells were sensitive to high pressure of gases. In this latter case, two inactivation kinetics were observed. For holding time up to 1 h, the inactivation rate increased to 4 log and was linked to a loss of membrane integrity and the presence of damage on the cell wall. In such case cell inactivation would be due to gas sorption and desorption phenomena which would rupture dried cells during a fast pressure release. Gas sorption would occur in cell lipid phases. For longer holding times, the inactivation rate increased more slightly due to compression effects and/or to a slower gas sorption. Water therefore played a key role in cell sensitivity to fast gas pressure release. Two hypotheses were proposed to explain this phenomenon: the rigidity of vitrified dried cells and the presence of glassy solid phases which would favor intracellular gas expansion. Our results showed that dried microorganisms can be ruptured and inactivated by a fast pressure release with gases. Biotechnol. Bioeng. 2008;101: 729,738. © 2008 Wiley Periodicals, Inc. [source] | ||||||||||||||||||||||||||||