Calidad de la información sobre ejercicios en las páginas de Internet dirigida a sobrevivientes de cáncer de seno / Quality of the information on exercise found on websites aimed at breast cancer survivors

Objetivo. Describir la calidad de la información acerca de ejercicios en Internet dirigida a sobrevivientes de cáncer de seno. Método. El diseño del estudio es exploratorio descriptivo. Se evaluó la calidad de la información acerca de ejercicios en un total de 40 páginas de Internet: se utilizaron 3 instrumentos para evaluar la calidad de la información: Discern, InEje (calidad de la información de ejercicios) y FRES/Huertas. Resultados. Los porcentajes de los promedios obtenidos con respecto a la puntuación máxima posible para cada instrumento fueron: Discern 62,67%, InEje 15,23%, y FRES/Huertas 56,51%. Conclusión. La evidencia sugiere que es necesario mejorar la calidad de la información sobre ejercicios de las páginas de Internet en inglés y español para sobrevivientes de cáncer de seno (AU)

Goal: To analyze the changes produced by therapeutic massage on systemic autonomic activity by analyzing the modification of cardiac autonomic activity. Material and methods: A comparative study was performed on 15 women on the variability of heart rate variability (HRV) (RR interval) obtained by photoplethysmography for 2 20-minute sessions: control and massage. HRV was measured at 4 different times for periods of 5 minutes each. The massage session consisted of effleurage massage and wide-ranging sliding pressure. In addition, the participants had to fill out the well-being visual analogue scale (Well Being VAS) questionnaire immediately after the control and massage session. Results: The paired Student’s t-test was used to compare the results obtained. Pearson correlation coefficient was used to quantify the relationship existing between the different times in each one of the parameters. A statistically significant increase was observed in HRV (total power) as well as an increase in parasympathetic activity in the massage session during the last 5 minutes (relative to baseline) compared to control session. However, this response tends to decrease 5 minutes after its interruption/timeout. Finally, the Well Being VAS score shows a significant increase after the massage. However, its gain is not correlated to the changes in the physiological variables. Conclusions: The massage applied on healthy subjects affects the autonomic nervous system (AU)

Co-infection with Ascaris lumbricoides modulates protective immune responses against Giardia duodenalis in school Venezuelan rural children.

We evaluated the effect of Ascaris lumbricoides on Giardia duodenalis infection and TH1/TH2 type immune mechanisms toward this parasite in 251 rural parasitized and 70 urban non-parasitized school children. The children were classified according to light (0-5000 eggs/g faeces) or moderate (>5001-50,000 eggs/g faeces) A. lumbricoides infection. Anti G. duodenalis skin hyper-reactivity, IgE, IgG, IL-13, IFN γ, IL6 and IL-10 levels were compared among G. duodenalis infected and non-infected children according to light or moderate A. lumbricoides infection. It was found that 62% of the A. lumbricoides moderately infected children were co-infected by G. duodenalis compared to 45% of the lightly infected group. After treatment, 42% of the A. lumbricoides moderately group were infected with G. duodenalis compared to 11% of their lightly counterparts, being A. lumbricoides IL-10 levels higher (p<0.0001) in the moderately infected group. In the A. lumbricoides lightly parasitized children, G. duodenalis infection was associated to a significant increase (p<0.005) of the levels of G. duodenalis IL-13, IFN-γ, IL-6, IgE, IgG and skin test hyper reactivity. In contrast, there was no effect of G. duodenalis infection in the elevation of these parameters among the A. lumbricoides moderately parasitized group, being those levels similarly lower as those observed in the control group. Inverse correlations were found between the levels of anti G duodenalis antibodies, skin test hyper-reactivity and cytokines with the intensity of A. lumbricoides infection (p>0.0001) and A. lumbricoides IL-10 levels (p>0.0001), suggesting that co-infection with A. lumbricoides may affect both TH1 and TH2 type immunity against G. duodenalis that may play an important role in the susceptibility to the infection after chemotherapy in children from endemic areas.

Flocculent activity of a recombinant protein from Moringa oleifera Lam. seeds.

Seeds of the tropical tree Moringa oleifera contain small storage proteins able to flocculate particles in suspension in water. The cDNA encoding one of these flocculent proteins, MO(2.1), was cloned and the recombinant protein was expressed in Escherichia coli. The flocculent activity of the purified recombinant MO(2.1)was assayed on clays and bacteria using light and confocal microscopy and GFP-overexpressing bacteria. We show that MO(2.1)is able to aggregate montmorillonite clay particles as well as gram-positive and gram-negative bacteria. We discuss the use of recombinant proteins to study flocculating properties and improve water purification processes.

In vitro cationic lipid-mediated gene delivery with fluorinated glycerophosphoethanolamine helper lipids.

There is a need for the development of nonviral gene transfer systems with improved and original properties. "Fluorinated" lipoplexes are such candidates, as supported by the remarkably higher in vitro and in vivo transfection potency found for such fluorinated lipoplexes as compared with conventional ones or even with PEI-based polyplexes (Boussif, O., Gaucheron, J., Boulanger, C., Santaella, C., Kolbe, H. V. J., Vierling, P. (2001) Enhanced in vitro and in vivo cationic lipid-mediated gene delivery with a fluorinated glycerophosphoethanolamine helper lipid. J. Gene Med. 3, 109-114). Here, we describe the synthesis of fluorinated glycerophosphoethanolamines (F-PEs), close analogues of dioleoylphosphatidylethanolamine (DOPE), and report on their lipid helper properties vs that of DOPE, as in vitro gene transfer components of fluorinated lipoplexes based on pcTG90, DOGS (Transfectam), or DOTAP. To evaluate the contribution of the F-PEs to in vitro lipoplex-mediated gene transfer, we examined the effect of including the F-PEs in lipoplexes formulated with these cationic lipids (CL) for various CL:DOPE:F-PE molar ratios [1:(1 - x):x with x = 0, 0.5 and 1; 1:(2 - y):y with y = 0, 1, 1.5, and 2], and various N/P ratios (from 10 to 0.8, N = number of CL amines, P = number of DNA phosphates). Irrespective of the F-PE chemical structure, of the colipid F-PE:DOPE composition, and of the N/P ratio, comparable transfection levels to those of their respective control DOPE lipoplexes were most frequently obtained when using one of the F-PEs as colipid of DOGS, pcTG90, or DOTAP in place of part of or of all DOPE. However, a large proportion of DOGS-based lipoplexes were found to display a higher transfection efficiency when formulated with the F-PEs rather than with DOPE alone while the opposite tendency was evidenced for the DOTAP-based lipoplexes. The present work indicates that "fluorinated" lipoplexes formulated with fluorinated helper lipids and conventional cationic lipids are very attractive candidates for gene delivery. It confirms further that lipophobicity and restricted miscibility of the lipoplex lipids with the endogenous lipids does not preclude efficient gene transfer and expression. Their transfection potency is rather attributable to their unique lipophobic and hydrophobic character (resulting from the formulation of DNA with fluorinated lipids), thus preventing to some extent DNA from interactions with lipophilic and hydrophilic biocompounds, and from degradation.

Improved in vitro gene transfer mediated by fluorinated lipoplexes in the presence of a bile salt surfactant.

BACKGROUND: Progress in the field of gene transfer with non-viral vectors requires systems that allow efficient gene expression in the presence of biological fluids such as pulmonary surfactants, for gene transfer to the respiratory epithelium for cystic fibrosis gene therapy, or bile salts (which contain powerful anionic detergents), for gene transfer to the biliary epithelium for gene therapy of the hepatobiliary disease associated with cystic fibrosis (CF). We have performed a comparative analysis of the disintegration and DNA accessibility of fluorinated and conventional lipoplexes, and their in vitro transfection potential in the presence of a powerful biliary surfactant. METHODS: The disintegration and DNA accessibility of conventional and fluorinated cationic lipoplexes and their in vitro transfection efficiency of human lung carcinoma epithelial A549 cells were studied in the presence of various concentrations of sodium taurocholate (STC), an anionic bile salt detergent. The conventional and fluorinated lipoplexes were formulated from Transfectam" (or DOGS) and from fluorinated lipospermines, analogs of DOGS, respectively, and a luciferase reporter plasmid. The fluorinated lipids used in the present study were selected for their different degrees of fluorination in order to investigate the impact on stability and transfection. The effects of the detergent on lipoplex integrity were examined by evaluating the ability of the lipospermines to prevent, in the presence of the surfactant, ethidium bromide (BET) intercalation into the plasmid (fluorescence monitoring). RESULTS: Fluorinated cationic lipoplexes exhibited greater stability than DOGS lipoplexes with respect to STC lytic activity. Indeed, while the DOGS lipoplexes were fully disintegrated at a [STC]/[lipid] molar ratio of 1,320, all the DNA intercalation sites of the most fluorinated lipoplexes investigated became accessible to BET for a two-fold higher [STC]/[lipid] molar ratio. A higher transfection potential in the presence of the detergent was also shown for the fluorinated lipoplexes as compared with the DOGS preparation. At a 10 mM concentration of STC and at a [STC]/[lipid] molar ratio of 264, lipofection when mediated by DOGS was fully inhibited while the detergent had no inhibitory effects on the lipofection mediated by the fluorinated DF4C11-GS [spermine-5-carboxyglycine N,N-di-11-(F-butyl)-undecylamide] or DF6E11-GS [spermine-5-carboxyglycine N,N-di-[11-(F-hexyl)-undec-10-enyl]amide] lipospermines. A higher detergent concentration (up to 17.5 mM) and a higher [STC]/[lipid] ratio (up to 462) were necessary to inhibit lipofection by the fluorinated formulations. Overall, the lipoplex stability and transfection potential in the presence of the detergent was found to improve with increasing degrees of fluorination of the lipospermines. CONCLUSIONS: The present work shows improved stability of, and higher lipofection levels with, fluorinated lipoplexes in the presence of surfactants. The results confirm the very promising potential of fluorinated lipoplexes as gene transfer vectors. These compounds constitute a very attractive alternative to their more conventional homologs. The correlation found between the degree of fluorination of the lipoplexes, their stability and their lipofection levels suggests that enhanced lipophobic and hydrophobic properties protect them against disintegration and, consequently, prevents DNA from being degraded and from interacting with lipophilic and hydrophilic biocompounds responsible for lipofection inhibition.

Regulation of serine-type exoproteinases by endogenous inhibitors present in exoantigens of the mycelial form of Paracoccidioides brasiliensis.

We have partially characterized some biochemical properties of exoproteinases secreted into culture medium by the mycelial form of Paracoccidioides brasiliensis, a dimorphic fungus that causes human disease in Latin America. Proteinase activity was analyzed in solid- and liquid-phase systems using zymography and Azocoll, respectively. Minimal or no gelatinase activity was observed by zymography in the crude filtrates among proteins with a relative mobility greater than 200 kDa. When the crude filtrate was fractionated by isoelectric focusing or ion exchange chromatography, we observed striking activation of gelatinases, both those of high apparent molecular mass and alkaline isoelectric points (pI), as well as those of lower molecular mass and acidic pI. The apparent high molecular mass gelatinases, pI 10, showed optimal activity at pH 7.0. They were totally inhibited by phenylmethylsulfonylfluoride and partially inhibited by incubation with previously neutralized fractions of pI 5.4 and 6.1. The latter inhibition could be reversed by exposure to 10% isopropanol. These results provide evidence of regulatory mechanisms controlling proteinase activity in secreted proteins. The principal mechanism appears to be the formation of reversible complexes with endogenous inhibitors.

In vitro gene transfer with a novel galactosylated spermine bolaamphiphile.

We describe the synthesis of a alpha-galacto-omega-spermine bolaamphiphile (GalSper) and report on the gene transfer mediated with lipoplexes it forms either when used alone or in conjunction with DOPE or with DOGS (Transfectam). Lipofection with GalSper was investigated with human HepG2 or murine BNL-CL2 hepatocytes expressing the asialo-glycoprotein (ASGP) receptor, which displays a high affinity for galactosyl residues, or with A549 cells which do not express ASGP. Although lower luciferase expression levels in BNL-CL2 and in HepG2 cells were obtained with GalSper/DOPE N/P 2.5 lipoplexes as compared with control DOGS/DOPE N/P 2.5 particles or with the more positively charged N/P 5 particles (yet through a different mechanism), specific receptor-mediated endocytosis of DNA can be achieved with this targeted cationic GalSper bolaamphiphile presenting a single galactose residue. The present work suggests that GalSper-based DNA formulations appear as promising synthetic vectors for specific gene delivery to ASGP(+) cells.

Enhanced in vitro and in vivo cationic lipid-mediated gene delivery with a fluorinated glycerophosphoethanolamine helper lipid.

BACKGROUND: One of the main drawbacks of synthetic, non-viral gene vectors is their relatively low in vivo efficiency when compared with viral vectors. The present paper describes the use of a partially fluorinated glycerophosphoethanolamine (F-PE), a close analog of DOPE, which, as a helper lipid with the cationic lipopolyamine pcTG90, increases its in vitro and in vivo gene transfer capability to a larger extent than DOPE. METHODS: To evaluate the contribution of F-PE to lipoplex-mediated gene transfer, the effect of including F-PE in lipoplexes formulated with the lipopolyamine pcTG90 for various pcTG90/DOPE/F-PE molar ratios [1:(1-x): x; 1:(2-y):y] was examined. For the in vitro analyses on human lung carcinoma epithelial A549 cells, the lipoplexes were formulated with the luciferase reporter plasmid pTG11033 using various N/P ratios (from 10 to 0.8, N = number of pcTG90 amines, P = number of DNA phosphates). The in vivo analyses were performed (1) with the luciferase reporter plasmid pCMV-Luc, which gives higher luciferase expression in the lung than pcTG11033; (2) with pcTG90/co-lipid(s) (1:2) lipoplexes which yield higher expression than the (1:1) formulations; and (3) by intravenous (iv) injection into the tail vein of mice. RESULTS: The efficiency of the F-PE lipoplexes to transfect in vitro A549 cells was significantly higher (5-90-fold) than that of DOPE lipoplexes, when formulated in HEPES. However, when formulated in 5% glucose, both co-lipids display a comparable transfection helper potential. Most remarkably, an up to eight-fold increase of luciferase expression could be measured in the lung after iv injection of pcTG90/F-PE (1:2) N/P 5 lipoplexes as compared with the pcTG90/DOPE lipoplexes. It led also to higher luciferase expression than PEI(ExGen500)/pCMV-Luc N/P 10 polyplexes. Besides expression in lung, low levels of luciferase expression were also observed in heart, spleen and liver. CONCLUSION: The present work, showing a higher in vitro and in vivo transfection potential for lipoplexes formulated with a partially fluorinated co-lipid as compared with its analogous DOPE lipoplexes or PEI polyplexes, indicates that 'fluorinated' lipoplexes are attractive candidates for in vivo applications.

Highly fluorinated lipospermines for gene transfer: synthesis and evaluation of their in vitro transfection efficiency.

Fluorinated double-chain lipospermines (one or both of these chains being ended by a highly fluorinated tail of various length) which are close analogues of DOGS (Transfectam) were designed as synthetic vectors for gene delivery. For N/P ratios (N = number of amine functions of the lipid; P = number of DNA phosphates) from 0.8 to 10, these lipospermines condensed DNA, with or without the use of DOPE, to form fluorinated lipoplexes. The efficiency of the fluorinated lipoplexes to transfect lung epithelial A549 cells was significantly higher than that of the DOGS lipoplexes. No specific cell toxicity was evidenced for the fluorinated lipoplexes as compared to that of the DOGS ones. The palette of structural elements explored allowed to determine those required for efficient transfection, highlighting the importance of highly fluorinated chains, the unique properties of unsaturated double-chain lipids and of the use of DOPE as helper lipid on transfection.

Synthesis of single- and double-chain fluorocarbon and hydrocarbon galactosyl amphiphiles and their anti-HIV-1 activity.

Galactosylceramide (GalCer) is an alternative receptor allowing HIV-1 entry into CD4(-)/GalCer(+) cells. This glycosphingolipid recognizes the V3 loop of HIV gp120, which plays a key role in the fusion of the HIV envelope and cellular membrane. To inhibit HIV uptake and infection, we designed and synthesized analogs of GalCer. These amphiphiles and bolaamphiphiles consist of single and double hydrocarbon and/or fluorocarbon chain beta-linked to galactose and galactosamine. They derive from serine (GalSer), cysteine (GalCys), and ethanolamine (GalAE). The anti-HIV activity and cytotoxicity of these galactolipids were evaluated in vitro on CEM-SS (a CD4(+) cell line), HT-29, a CD4(-) cell line expressing high levels of GalCer receptor, and/or HT29 genetically modified to express CD4. GalSer and GalAE derivatives, tested in aqueous medium or as part of liposome preparation, showed moderate anti-HIV-1 activities (IC50 in the 20-220 microM range), whereas none of the GalCys derivatives was found to be active. Moreover, only some of these anti-HIV active analogs inhibited the binding of [3H]suramin (a polysulfonyl compound which displays a high affinity for the V3 loop) to SPC3, a synthetic peptide which contains the conserved GPGRAF region of the V3 loop. Our results most likely indicate that the neutralization of the virion through masking of this conserved V3 loop region is not the only mechanism involved in the HIV-1 antiviral activity of our GalCer analogs.

[Tuberous angioma of the glans penis: treatment with laser and local anesthesia]. / Angioma tuberoso del glande del pene: tratamiento con láser y anestesia local.

A case of angioma tuberous of the glans penis treated with Neodymiun:Yag laser under local anesthesia in a eleven-years-old outpatient is reported. These lesions are extremely rare. Local excision of this tumor was accepted treatment, but we think that laser treatment (Neodymiun:Yag) is far superior to surgical excision and we think this treatment of choice. The particularity of the case we report, is aside the rarity, the possibility of treatment in an outpatient child, with local anesthesia and excellent tolerance.

Angioma tuberoso del glande del pene: tratamiento con láser y anestesia local / Angioma tuberous of the glans penis: treatment with laser and local anesthesia

Presentamos un caso de angioma tuberoso del glande del pene tratado con láser Neodimio: YAG, bajo anestesia local en un paciente ambulatorio de once años. Estas lesiones son extremadamente raras. La excisión local de este tumor es el tratamiento comúnmente aceptado, no obstante nosotros creemos que el tratamiento con láser Neodimio: YAG ofrece más beneficios que la extirpación quirúrgica, y pensamos que este es el tratamiento de elección. La particularidad de este caso que presentamos es, además de su rareza, la posibilidad de tratamiento ambulatorio en un niño con anestesia local y excelente tolerancia (AU)

Lipopolycationic telomers for gene transfer: synthesis and evaluation of their in vitro transfection efficiency.

We report on the synthesis of a series of lipopolyamine telomers I-14,n, I-18,n, and II-18,n and on their in vitro gene-transfer capability. Their structure consists of a polyamine polar moiety, including n primary amine functions (from 1 to 70), connected to a hydrophobic moiety, including two hydrocarbon C14 or C18 chains, through a mercaptopropanoyl or mercaptoglyceryl unit and an amide or ether function. They were obtained by telomerization of N-[2-[(BOC)aminoethyl]]acrylamide with N,N-ditetradecyl- and N,N-dioctadecylpropanamide-3-thiol and rac-1,2-dioctadecyloxypropane-3-thiol, respectively, then BOC deprotection. For N/P ratios (N = number of telomer amine equivalents; P = number of DNA phosphates) from 0.8 to 10, these lipopolyamines condensed DNA, with or without the use of DOPE, forming lipopolyplexes or teloplexes of mean sizes less than 200 nm. Some trends, structure-activity and structure-toxicity relationships, were established to achieve both highest in vitro transfection levels and cell viability. Thus, DNA formulations based on telomers I-14,20 and I-18,20 and for N/P ratios lower than 5 led to the most efficient teloplex formulations for plasmid delivery to lung epithelial A549 cells.

Phase behavior of fluorocarbon and hydrocarbon double-chain hydroxylated and galactosylated amphiphiles and bolaamphiphiles. Long-term shelf-stability of their liposomes.

This paper describes the morphological characterization, by freeze-fracture electron microscopy, and the thermotropic phase behavior, by differential scanning calorimetry and/or X-ray scattering, of aqueous dispersions of various hydroxylated and galactosylated double-chain amphiphiles and bolaamphiphiles, several of them containing one or two hydrophobic fluorocarbon chains. Colloidal systems are observed in water with the hydroxylated hydrocarbon or fluorocarbon bolaamphiphiles only when they are dispersed with a co-amphiphile such as rac-1,2-dimyristoylphosphatidylcholine (DMPC) or rac-1,2-distearoylphosphatidylcholine (DSPC). Liposomes are formed providing the relative content of bolaamphiphiles does not exceed 20% mol. Most of these liposomes can be thermally sterilized and stored at room temperature for several months without any significant modification of their size and size distribution. The hydrocarbon galactosylated bolaamphiphile HO[C24][C12]Gal forms in water a lamellar phase (the gel to liquid-crystal phase transition is complete at 45 degrees C) and a Im3m cubic phase above 47 degrees C. The fluorocarbon HO[C24][F6C5]Gal analog displays a more complex and metastable phase behavior. The fluorinated non-bolaform galactosylated [F8C7][C16]AEGal and SerGal amphiphiles form lamellar phases in water. Low amounts (10% molar ratio) of the HO[C24][F6C5]Gal or HO[C24][C12]Gal bolaamphiphiles or of the single-headed [F8C7][C16]AEGal improve substantially the shelf-stability of reference phospholipon/cholesterol 2/1 liposomes. These liposomes when co-formulated with a single-headed amphiphile from the SerGal series are by far less stable.

Improved stability of highly fluorinated phospholipid-based vesicles in the presence of bile salts.

The stability of fluorinated phospholipid-based vesicles in terms of detergent-induced release of encapsulated carboxyfluorescein has been evaluated. The fluorinated liposomes are substantially more resistant towards the lytic action of sodium taurocholate than conventional DSPC or even DSPC/CH 1/1 liposomes. Concerning structure/permeability relationships, the larger the fluorination degree of the membrane, the higher the resistance of the fluorinated liposomes to their destruction by the detergent. These results show that fluorinated liposomes have a promising potential as drug carrier and delivery systems for oral administration.

Transmembrane pH-driven Na+ permeability of fluorinated phospholipid-based membranes.

The permeability to the H+/Na+ exchange of fluorinated phospholipid-based membranes has been evaluated by measuring the dissipation rate of a liposomal transmembrane pH gradient in the presence of Na+. The fluorinated liposomes are made from fluorocarbon/hydrocarbon or fluorocarbon/fluorocarbon double-chain ether-connected glycerophosphocholines or amido-connected phosphocholines deriving from diaminopropanol or serine. The fluorocarbon/hydrocarbon mixed-chain phospholipids, as compared to the fluorocarbon/fluorocarbon ones, form membranes that are substantially more able to maintain a transmembrane pH gradient in the presence of NA+ and display a lower Na+ permeability. However, these membranes are more permeable to the H+/Na/ exchange than conventional DSPC (1,2-distearoylphosphatidylcholine) ones. Our results indicate a detrimental impact of the membrane fluorination degree on H+/Na+ permeability: the lower the fluorination degree of the membrane, the lower its H+/Na+ permeability. Concerning structure/permeability relationships, it appears that the replacement of the ester connecting bond in their fluorinated phosphatidylcholine analogues for an ether or amide one lowers the transmembrane H+/Na+ exchange.

A follow-up study of multibacillary Hansen's disease patients treated with multidrug therapy (MDT) or MDT + immunotherapy (IMT).

Multibacillary (MB) leprosy patients treated with multidrug therapy (MDT) or MDT + immunotherapy (IMT) with BCG + heat-killed Mycobacterium leprae were tested annually for their ability to proliferate in vitro to the mycobacterial antigens BCG, M. leprae soluble extract, and intact M. leprae. IgM antibody responses to phenolic glycolipid I (PGL-I) were measured, as well as serum nitrite levels in patients' sera, before, during and after treatment. Patients who received only MDT did not present cellular reactivity to intact M. leprae antigens, in contrast to the results obtained with BCG, which elicited reactivity at time zero, that increased after treatment. Regarding PGL-I antibody variations in relation to the initial value, we observed a statistically significant marked decrease at the end of 2 years which continued to fall in successive evaluations. MB patients showed high initial serum nitrite concentrations which dropped drastically with treatment. This decay was apparently associated with the bacillary load present in these patients. The group submitted to IMT + MDT showed high and long-lasting T-cell responses to mycobacterial antigens in a significant number of initially unresponsive MB patients. There was a marked increase to M. leprae soluble extract and BCG, as well as a more variable response to whole bacilli. The antibody levels in this group of patients are sustained for a somewhat longer period and decreased more slowly during the 5-year follow up.

Membrane permeability and stability of liposomes made from highly fluorinated double-chain phosphocholines derived from diaminopropanol, serine or ethanolamine.

The release of encapsulated carboxyfluorescein (CF) from liposomes made from various fluorinated amido-connected double-chain phosphocholines and their membrane permeability have been investigated at 37 degrees C in buffer and in human serum. These fluorinated membranes and liposomes display lower permeability coefficients and are able to retain more efficiently encapsulated CF than any of their respective conventional counterparts. Several of these liposomes are as effective as the first generation of liposomes based on fluorinated phosphatidylcholines, indicating that the chemical junction (ester/amide) and nature of the unit (glycerol, diaminopropanol, serine, ethanolamine) connecting the hydrophobic chains to the phosphocholine polar head have no significant effect on permeability and CF release. Our results show further that a fluorinated intramembrane layer reduces significantly the permeability of membranes in a liquid-crystalline state, protects the liposomes from the destabilizing effects of serum, and even increases their stability (in terms of dye retention) in serum when the membranes are in the gel state.

Phase behavior of fluorocarbon di-O-alkyl-glycerophosphocholines and glycerophosphoethanolamines and long-term shelf stability of fluorinated liposomes.

This paper is devoted to the morphological characterization, by freeze-fracture electron microscopy, and to the thermotropic phase behavior, by differential scanning calorimetry and X-ray diffraction of the aqueous dispersions of various fluorocarbon/fluorocarbon or mixed fluorocarbon/hydrocarbon 1,2- or 1,3-di-O-alkyl-glycerophosphocholines (PC) and 1,2-di-O-alkyl-glycerophosphoethanolamines (PE). The fluorinated PCs form classical lamellar phases and liposomes while an interdigitated lamellar phase has been evidenced for a hydrocarbon 1,3-analog. The fluorinated PEs display a lamellar to hexagonal phase transition which occurs almost simultaneously with the gel-to-fluid lamellar phase transition. The impact of each of the structural features [ether vs ester chemical junction connecting the hydrophobic chains on glycerol, their position (1,2- vs 1,3 isomers), number and length of the perfluoroalkylated chains, length of the fluorinated tail and hydrocarbon spacer, PC vs PE polar head] of the fluorinated phospholipids on the phase transition thermodynamic parameters (Tc, delta H, delta S) is discussed. Most of the liposomes formed from the fluorinated ether-PCs display a remarkable long-term shelf stability: they can be thermally sterilized and stored at room temperature for several months without any significant modification of their size and size distribution.