Vascular dysfunction following breath-hold diving.

The pathogenesis of predominantly neurological decompression sickness (DCS) is multifactorial. In SCUBA diving, besides gas bubbles, DCS has been linked to microparticle release, impaired endothelial function, and platelet activation. This study focused on vascular damage and its potential role in the genesis of DCS in breath-hold diving. Eleven breath-hold divers participated in a field study comprising eight deep breath-hold dives with short surface periods and repetitive breath-hold dives lasting for 6 h. Endothelium-dependent vasodilation of the brachial artery, via flow-mediated dilation (FMD), and the number of microparticles (MPs) were assessed before and after each protocol. All measures were analyzed by two-way within-subject ANOVA (2 × 2 ANOVA; factors: time and protocol). Absolute FMD was reduced following both diving protocols (p < 0.001), with no interaction (p = 0.288) or main effect of protocol (p = 0.151). There was a significant difference in the total number of circulating MPs between protocols (p = 0.007), where both increased post-dive (p = 0.012). The number of CD31+/CD41- and CD66b+ MP subtypes, although different between protocols (p < 0.001), also increased by 41.0% ± 56.6% (p = 0.050) and 60.0% ± 53.2% (p = 0.045) following deep and repetitive breath-hold dives, respectively. Both deep and repetitive breath-hold diving lead to endothelial dysfunction that may play an important role in the genesis of neurological DCS.

Increasing procoagulant activity of circulating microparticles in patients living with HIV.

OBJECTIVES: HIV-infected individuals are at higher risk of non-AIDS diseases associated with procoagulant status. Microparticles are elevated in disorders associated with thrombosis (e.g., cardiovascular diseases). We investigated the association between microparticle levels in untreated and treated HIV-infected subjects, and determined the association with immune status, viral replication, and duration of antiretroviral therapy. PATIENTS AND METHODS: We included 144 HIV-infected subjects, including 123 on antiretroviral therapy (ART) and 21 before treatment initiation. A control group of 40 HIV-negative healthy adults matched for age and sex was used for comparison of microparticle levels. Treated subjects were divided into five groups depending on the period of antiretroviral exposure. Statistically significant differences were determined by Kruskal-Wallis test and Chi2 test. The relation between microparticles and other parameters was assessed using Spearman's coefficient of correlation. RESULTS: Microparticle levels were significantly higher in treated and untreated HIV-infected subjects than in non-HIV-infected controls (P<0.001). The microparticle level was similar between the groups on treatment (P=0.913). No association between the microparticle level and CD4+ count, CD4+/CD8+ ratio, number of HIV-1 RNA copies, or duration of exposure to antiretroviral treatment was observed. CONCLUSION: Increased levels of microparticles may be due to processes independent of viral replication and CD4+ cell count, and microparticle release might persist even during viral suppression by antiretroviral treatment. Elevated microparticle levels might occur in response to other triggers.

[Vascular dysfunction in obstructive sleep apnoea: Implication of microparticules]. / Atteinte vasculaire associée au syndrome d'apnées hypopnées obstructives du sommeil : rôle des microparticules.

Obstructive sleep apnea (OSA) is associated with increased cardiovascular diseases, including myocardial infarction and stroke and promotes cardiovascular risk factors including diabetes and hypertension. OSA has also been proposed to have a direct proatherogenic effects. Recent studies have investigated the role of microparticles (MPs) in the atherogenic process. MPs are small plasma membrane vesicles that can be released by a variety of vascular or blood cells and that contain membrane and cytosolic elements. Case-control studies have suggested that OSA is associated with an increase in circulating platelet-, endothelial- and leukocyte-derived MPs. MPs from OSA patients injected to mice have also been shown to induce vascular inflammation and endothelial dysfunction. In this article, we provide an overview of the main characteristics of MPs expressed in OSA and their potential role in the atherogenic process.

[Membranous microparticles and respiratory disease]. / Microparticules membranaires et maladies respiratoires.

Microparticles (MP) are plasmic membrane fragments released from cells after physiological stimulation or stress conditions like inflammation or infection. Their production is correlated to the rate of cell apoptosis. All types of cells can produce MP but they are produced mainly by platelets, endothelial cells, and leukocytes. They carry many bio-active molecules on their surface, specific to the parental cell, giving them the ability to be biomarkers and bio-effectors. MP are present in circulating blood, tissues and many biological fluids. Circulating MP levels can change during the course of many diseases. They have been the subject of many studies in the fields of cardiovascular disease and oncology. In the lungs, they are present in circulating blood and in the airways. They seem to have a role in pulmonary homeostasis in physiological situations and also in the expression of several disease processes. In this review of the literature, we were interested in the quantitative and qualitative variations in MP and their impact in airway diseases like chronic obstructive pulmonary disease (COPD) and asthma, pulmonary fibrosis and pulmonary hypertension.

Gentamicin-loaded poly(lactic-co-glycolic acid) microparticles for the prevention of maxillofacial and orthopedic implant infections.

Trauma and orthopedic surgery can cause infections as any open surgical procedures. Such complications occur in only1 to 5% of the cases, but the treatment is rather complicated due to bacterial biofilm formation and limited drug access to the site of infection upon systemic administration. An interesting strategy to overcome this type of complications is to prevent bacterial proliferation and biofilm formation via the local and controlled release of antibiotic drugs from the implant itself. Obviously, the incorporation of the drug into the implant should not affect the latter's biological and mechanical properties. In this context, we optimized the preparation process for gentamicin-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles, which can be incorporated in the macropores of calcium phosphate-based bone substitutes. Microparticles were prepared using a double emulsion solvent extraction/evaporation technique. The processing parameters were optimized in order to provide an average microparticle size of about 60µm, allowing for incorporation inside the macropores (100µm) of the hydroxyapatite scaffold. Gentamicin-loaded PLGA microparticles showed a sustained release for 25-30days and a rapid antibacterial activity due to a burst effect, the extent of which was controlled by the initial loading of the microparticles. SEM pictures revealed a highly porous microparticle structure, which can help to reduce the micro environmental pH drop and autocatalytic effects. The biological evaluation showed the cytocompatibility and non-hemolytic property of the microparticles, and the antibacterial activity against Staphylococcus aureus under the given conditions.

Influence of a low-carbohydrate diet on endothelial microvesicles in overweight women.

Low-carbohydrate diets (LCD) are increasing in popularity, but their effect on vascular health has been questioned. Endothelial microvesicles (EMV) are membrane-derived vesicles with the potential to act as a sensitive prognostic biomarker of vascular health and endothelial function. The aim of this study was to examine the influence of a LCD on EMV and other endothelial biomarkers of protein origin. Twenty-four overweight women (age, 48.4 ± 0.6 years; height, 1.60 ± 0.07 m; body mass, 76.5 ± 9.1 kg; body mass index, 28.1 ± 2.7 kg·m(-2); waist circumference, 84.1 ± 7.4 cm; mean ± standard deviation) were randomised to either 24 weeks on their normal diet (ND) or a LCD, after which they crossed over to 24 weeks on the alternative diet. Participants were assisted in reducing carbohydrate intake, but not below 40 g·day(-1). Body composition and endothelial biomarkers were assessed at the crossover point and at the end of the study. Daily carbohydrate intake (87 ± 7 versus 179 ± 11 g) and the percentage of energy derived from carbohydrate (29% versus 44%) were lower (p < 0.05) on the LCD compared to the ND, but absolute fat and saturated fat intake were unchanged. Body mass and waist circumference were 3.7 ± 0.8 kg and 3.5 ± 1.0 cm lower (p < 0.05), respectively, after the LCD compared with the ND phases. CD31(+)CD41(-)EMV, soluble (s) thrombomodulin, sE-selectin, sP-selectin, serum amyloid A and C-reactive protein were lower (p < 0.05) after the LCD compared to the ND, but serum lipids and apolipoproteins were not different. EMV along with a range of endothelial and inflammatory biomarkers are reduced by a LCD that involves modest weight loss.

Interest of cyclodextrins in spray-dried microparticles formulation for sustained pulmonary delivery of budesonide.

To achieve an efficient lung delivery and efficacy, both active ingredient aerosolisation properties and permeability through the lung need to be optimized. To overcome these challenges, the present studies aim to develop cyclodextrin-based spray-dried microparticles containing a therapeutic corticosteroid (budesonide) that could be used to control airway inflammation associated with asthma. The complexation between budesonide and hydroxypropyl-ß-cyclodextrin (HPBCD) has been investigated. Production of inhalation powders was carried out using a bi-fluid nozzle spray dryer and was optimized based on a design of experiments. Spray-dried microparticles display a specific "deflated-ball like shape" associated with an appropriate size for inhalation. Aerodynamic assessment show that the fine particle fraction was increased compared to a classical lactose-based budesonide formulation (44.05 vs 26.24%). Moreover, the budesonide permeability out of the lung was shown to be reduced in the presence of cyclodextrin complexes. The interest of this sustained budesonide release was evaluated in a mouse model of asthma. The anti-inflammatory effect was compared to a non-complexed budesonide formulation at the same concentration and attests the higher anti-inflammatory activity reach with the cyclodextrin-based formulation. This strategy could therefore be of particular interest for improving lung targeting while decreasing systemic side effects associated with high doses of corticosteroids. In conclusion, this works reports that cyclodextrins could be used in powder for inhalation, both for their abilities to improve active ingredient aerosolisation properties and further to their dissolution in lung fluid, to decrease permeability out of the lungs leading to an optimized activity profile.

Incremento de disolución de un derivado del furano mediante la técnica de secado por atomización / Improvement of Furane derivate dissolution rate using spray drying technique

Objetivo: incrementar la solubilidad en agua del 2-bromo-5-(2-bromo-2-nitrovinyl)-furano (G1), un ingrediente farmacéuticamente activo sintetizado por el Centro de Bioactivos Químicos de la Universidad Central de Las Villas, con potente acción bactericida y fungicida, mediante la elaboración de macropartículas de dispersiones sólidas utilizando un proceso de secado por atomización. Métodos: se realizó un ensayo preliminar de secado por atomización de la suspensión de G1, compuesta por: 10 g de G1, 1 g de Aerosil (Aerosil®, Degusa, Bélgica), 1 g de laurilsulfato de sodio y 100 mL de agua. La atomización se efectuó en un equipo de laboratorio (Buchi Mini Dryer spray) a 90 ºC. La dispersión sólida obtenida fue caracterizada físico-químicamente mediante difracción de rayos X, granulometría láser por el método de difracción angular, calorimetría diferencial de barrido, microscopia electrónica de barrido y espectrofotometría de absorción infraroja. Resultados: las partículas obtenidas presentaron un pequeño tamaño, forma esférica y un incremento de la cristalinidad del G-1; no se encontraron interacciones entre los componentes de la dispersión ni presencia de productos de degradación, y la solubilidad del G-1 en agua resultó notablemente incrementada. Conclusiones: el producto obtenido por la técnica de secado por atomización incrementó apreciablemente la solubilidad del G1 sin afectar los grupos funcionales, responsables de la actividad terapéutica que se le reportan al ingrediente activo estudiado. Estos alentadores resultados sugieren la necesidad de continuar estudios para la optimización del proceso y realizar al producto obtenido ensayos de estabilidad con el objetivo de su futura inclusión en formas farmacéuticas de dosificación.(AU)

Objective: to increase the solubility of 2-bromium-5(2-bromium-2-nitrovinyl)-furane (G1), one pharmaceutically active ingredient with potent bactericidal and fungicidal action, synthesized through the preparation of solid dispersion macroparticles based on spray-drying process in the Center of Chemical Bioactives of the Central University in Las Villas province. Methods: a preliminary spray-drying test of GI suspension made up of 10 g of G1, 1g of Aerosil (Aerosil®, Degusa, Bélgica), 1g of sodium laurylsulphate and 100 ml of water was made. A piece of lab equipment known as Buchi Mini Dryer spray served for the spraying at 90 ºC. The solid dispersion was characterized from the physical and chemical viewpoints through X-ray diffraction, laser granulometry based on angular diffraction method, differential scanning calorimetry, electronic scanning microscopy and infrared spectrophotometry. Results: the obtained particles were small, spherical and had increased G1 crystallinity. No interactions were found in the dispersion components; there were no degradation products, and G1 solubility was significantly increased. Conclusions: the product obtained from spray-drying technique substantially raised the solubility of G1 without affecting the functional groups, which are responsible for the reported therapeutic action of the studied active ingredient. These encouraging results endorse the need for further studies to optimizing the process and carrying out stability tests for the product to be included in the pharmaceutical forms of dosing in the future.(AU)

Incremento de disolución de un derivado del furano mediante la técnica de secado por atomización / Improvement of Furane derivate dissolution rate using spray drying technique

Objetivo: incrementar la solubilidad en agua del 2-bromo-5-(2-bromo-2-nitrovinyl)-furano (G1), un ingrediente farmacéuticamente activo sintetizado por el Centro de Bioactivos Químicos de la Universidad Central de Las Villas, con potente acción bactericida y fungicida, mediante la elaboración de macropartículas de dispersiones sólidas utilizando un proceso de secado por atomización. Métodos: se realizó un ensayo preliminar de secado por atomización de la suspensión de G1, compuesta por: 10 g de G1, 1 g de Aerosil (Aerosil®, Degusa, Bélgica), 1 g de laurilsulfato de sodio y 100 mL de agua. La atomización se efectuó en un equipo de laboratorio (Buchi Mini Dryer spray) a 90 ºC. La dispersión sólida obtenida fue caracterizada físico-químicamente mediante difracción de rayos X, granulometría láser por el método de difracción angular, calorimetría diferencial de barrido, microscopia electrónica de barrido y espectrofotometría de absorción infraroja. Resultados: las partículas obtenidas presentaron un pequeño tamaño, forma esférica y un incremento de la cristalinidad del G-1; no se encontraron interacciones entre los componentes de la dispersión ni presencia de productos de degradación, y la solubilidad del G-1 en agua resultó notablemente incrementada. Conclusiones: el producto obtenido por la técnica de secado por atomización incrementó apreciablemente la solubilidad del G1 sin afectar los grupos funcionales, responsables de la actividad terapéutica que se le reportan al ingrediente activo estudiado. Estos alentadores resultados sugieren la necesidad de continuar estudios para la optimización del proceso y realizar al producto obtenido ensayos de estabilidad con el objetivo de su futura inclusión en formas farmacéuticas de dosificación.

Objective: to increase the solubility of 2-bromium-5(2-bromium-2-nitrovinyl)-furane (G1), one pharmaceutically active ingredient with potent bactericidal and fungicidal action, synthesized through the preparation of solid dispersion macroparticles based on spray-drying process in the Center of Chemical Bioactives of the Central University in Las Villas province. Methods: a preliminary spray-drying test of GI suspension made up of 10 g of G1, 1g of Aerosil (Aerosil®, Degusa, Bélgica), 1g of sodium laurylsulphate and 100 ml of water was made. A piece of lab equipment known as Buchi Mini Dryer spray served for the spraying at 90 ºC. The solid dispersion was characterized from the physical and chemical viewpoints through X-ray diffraction, laser granulometry based on angular diffraction method, differential scanning calorimetry, electronic scanning microscopy and infrared spectrophotometry. Results: the obtained particles were small, spherical and had increased G1 crystallinity. No interactions were found in the dispersion components; there were no degradation products, and G1 solubility was significantly increased. Conclusions: the product obtained from spray-drying technique substantially raised the solubility of G1 without affecting the functional groups, which are responsible for the reported therapeutic action of the studied active ingredient. These encouraging results endorse the need for further studies to optimizing the process and carrying out stability tests for the product to be included in the pharmaceutical forms of dosing in the future.