Decay of HIV RNA in Seminal Plasma and Rectal Fluid in Treatment-Naive Adults Starting Antiretroviral Therapy With Dolutegravir Plus Lamivudine or Bictegravir/Emtricitabine/Tenofovir Alafenamide

BACKGROUND

Decay of HIV in seminal plasma (SP) and rectal fluid (RF) has not yet been described for the antiretroviral combination of dolutegravir (DTG) + lamivudine (3TC).

METHODS

In this randomized multicenter pilot trial, males who were antiretroviral naive were randomized (2:1) to DTG + 3TC or bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF). HIV-1 RNA was measured in blood plasma (BP), SP, and RF at baseline; days 3, 7, 14, and 28; and weeks 12 and 24.

RESULTS

Of 25 individuals enrolled, 24 completed the study (DTG + 3TC, n = 16; BIC/FTC/TAF, n = 8). No significant differences were observed between groups for median decline in HIV-1 RNA from baseline at each time point or median time to achieve HIV-1 RNA <20 copies/mL in BP and SP and <20 copies/swab in RF. HIV-1 RNA decay patterns were compared in individuals receiving DTG + 3TC. Despite significantly higher percentages for changes from baseline in BP, median (IQR) times to HIV-1 RNA suppression were shorter in SP (7 days; 0-8.75) and RF (10.5 days; 3-17.5) than in BP (28 days; 14-84; P < .001).

CONCLUSIONS

Comparable HIV-1 RNA decay in BP, SP, and RF was observed between DTG + 3TC and BIC/FTC/TAF. As shown with triple-drug integrase inhibitor-based regimens, rapid HIV-1 RNA suppression in SP and RF is achieved with DTG + 3TC, despite decay patterns differing from those of BP.

CLINICAL TRIALS REGISTRATION

EudraCT 2019-004109-28.

Doravirine Concentrations and Human Immunodeficiency Virus Type 1 RNA in the Genital Fluids of Virologically Suppressed Adults Switching to Doravirine Plus Emtricitabine/Tenofovir Alafenamide

Doravirine (DOR) concentrations and HIV-1 RNA were evaluated in genital fluids from adults with HIV on stable therapy who switched to DOR + FTC/TAF. High protein-unbound DOR concentrations were observed in both seminal plasma and cervicovaginal fluid. DOR + FTC/TAF maintained viral suppression in genital fluids in all but 1 participant.

Anatomic characteristics of the left atrium in subjects undergoing radiofrequency ablation for atrial fibrillation

OBJECTIVE

To analyze the anatomic characteristics of the left atrium and pulmonary veins in individuals undergoing ablation for atrial fibrillation and to identify possible anatomic factors related with recurrence.

MATERIAL AND METHODS

We retrospectively reviewed the CT angiography studies done to plan radiofrequency ablation for atrial fibrillation in 95 patients (57 men; mean age, 65 ± 10 y). We reviewed the anatomy of the pulmonary veins and recorded the diameters of their ostia as well as the diameter and volume of the left atrium. We analyzed these parameters according to the type of arrhythmia and the response to treatment.

RESULTS

In 71 (74.7%) patients, the anatomy of the pulmonary veins was normal (i.e., two right pulmonary veins and two left pulmonary veins). Compared to patients with paroxysmal atrial fibrillation, patients with persistent atrial fibrillation had slightly larger diameter of the left pulmonary veins (left superior pulmonary vein 17.9 ± 2.6 mm vs. 16.7 ± 2.2 mm, p = 0.04; left inferior pulmonary vein 15.3 ± 2 mm vs. 13.8 ± 2.2 mm, p = 0.009) and larger left atrial volume (91.9 ± 24.9 cm³ vs. 70.7 ± 20.3 mm³, p = 0.001). After 22.1 ± 12.1 months' mean follow-up, 41 patients had sinus rhythm. Compared to patients in whom the sinus rhythm was restored, patients with recurrence had greater left atrial volume (81.4 ± 23.0 mm³ vs. 71.1 ± 23.2 mm³, p = 0.03). No significant differences in pulmonary vein diameters or clinical parameters were observed between patients with recurrence and those without.

CONCLUSION

The volume of the left atrium is greater in patients with persistent atrial fibrillation and in those who do not respond to ablation.

Doravirine Achieves Adequate CSF Exposure and is Mostly Unbound to Proteins

We determined total and unbound concentrations of Doravirine (DOR) in cerebrospinal fluid (CSF) and blood plasma. Total and unbound DOR concentrations in CSF exceeded the EC50 value against wild-type virus (5.1 ng/mL) in all subjects suggesting that DOR may contribute to inhibit viral replication in this compartment.

[Non-invasive brain and spinal cord stimulation for motor and functional recovery after a spinal cord injury]

INTRODUCTION

Spinal cord injury is a traumatic or non-traumatic event that causes an alteration of sensory, motor or autonomic functioning and ultimately affects the physical, psychological and social well-being of the person who suffers it. A comprehensive approach to spinal cord injury requires many health resources and can place a considerable financial burden on patients, their families and the community.

AIM

To review the literature published to date on the use of non-invasive brain stimulation, including repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), and transcutaneous non-invasive spinal cord stimulation (tcSCS), as therapeutic strategies to improve the functionality of patients with spinal cord injury. The studies were grouped as addressing either non-invasive brain stimulation or non-invasive spinal cord stimulation.

DEVELOPMENT

Altogether 32 studies were identified: 21 involving brain stimulation (14 in rTMS and 7 in tDCS) and 11 with spinal cord stimulation (tcSCS). All the studies were conducted in adult patients who had undergone a spinal cord injury. Despite significant variability in treatment protocols, patient characteristics and clinical assessment, the changes observed were reported in almost all the studies without producing any side effects and with motor or functional improvement.

CONCLUSION

Non-invasive brain stimulation, as well as spinal cord stimulation, are promising techniques for the rehabilitation of patients with spinal cord injury due to their novelty, effectiveness and minimal side effects.

Híbridos pirenaicos de <em>Pedicularis (Orobanchaceae)</em>

Se describen dos nuevas notoespecies y una nueva variedad resultantes de la hibridación entre especies de Pedicularis sect. Rostratae en la cordillera pirenaica: P. ×pallidiflora (P. pyrenaica × P. tuberosa), P. ×aranensis (P. mixta × P. praetermissa) y P. ×pallidiflora var. palearensis. Además de las descripciones formales, se aportan datos sobre la distribución, ecología y abundancia respectivas. Otro híbrido pirenaico de la misma sección, P. ×monnieri (P. kerneri × P. pyrenaica), fue descrito hace algo más de un siglo, pero actualmente solo se conoce el material tipo, recolectado a principios del siglo XIX. Estos son los únicos nototaxones de Pedicularis indicados hasta el momento en los Pirineos.

Sobre la taxonomía y la nomenclatura de <em>Achillea ceretanica (Asteraceae)</em>, y su relación con otro microtaxon del agregado de <em>A. millefolium</em>

Se propone el estatus de especie y la combinación nomenclatural correspondiente para Achillea ceretanica, taxon diploide del agregado de A. millefolium endémico de los Pirineos orientales. Se refuta la sinonimización de A. monticola Martrin-Donos con A. ceretanica por ser la primera una estirpe octoploide del agregado netamente diferenciada de la anterior, y se aporta información sobre la distribución, ecología y frecuencia de ambas.

3D fibre architecture of fibre-reinforced sand

The mechanical behaviour of fibre-reinforced sands is primarily governed by the three-dimensional fibre architecture within the sand matrix. In laboratory, the normal procedures for sample preparation of fibre-sand mixtures generally produce a distribution of fibre orientations with a preferential bedding orientation, generating strength anisotropy of the composite's response under loading. While demonstrating the potential application of X-ray tomography to the analysis of fibre-reinforced soils, this paper provides for the first time a direct experimental description of the three-dimensional architecture of the fibres induced by the laboratory sample fabrication method. Miniature fibre reinforced sand samples were produced using two widely used laboratory sample fabrication techniques: the moist tamping and the moist vibration. It is shown that both laboratory fabrication methods create anisotropic fibre orientation with preferential sub-horizontal directions. The fibre orientation distribution does not seem to be affected by the concentration of fibres, at least for the fibre concentrations considered in this study and, for both fabrication methods, the fibre orientation distribution appears to be axisymmetric with respect to the vertical axis of the sample. The X-ray analysis also demonstrates the presence of an increased porosity in the fibre vicinity, which confirms the assumption of the "stolen void ratio" effect adopted in previous constitutive modelling. A fibre orientation distribution function is tested and a combined experimental and analytical method for fibre orientation determination is further validated.

Aportació al coneixement de l’herbari Trèmols de l’Institut Botànic de Barcelona

El herbario BC-Trèmols fue creado durante la segunda mitad del siglo XIX por el químico y botánico catalán Frederic Trèmols i Borrell. Entre 1930 y 1960, el técnico Antoni Marcos llevó a cabo una profunda revisión. La colección actual consta aproximadamente de unos 9000 pliegos; está formada por 58 volúmenes reordenados por Marcos, más otros dos con la estructura original, cuatro cajas de Hieracium y 85 cajas de material adicional. Hasta la fecha se han informatizado 22 de los volúmenes y las cuatro cajas de Hieracium (3695 especímenes), se ha llevado a cabo un inventario a nivel de género de todos los volúmenes y se ha informatizado el catálogo original del herbario y el fichero taxonómico existente. También se ha elaborado un inventario preliminar del contenido de las cajas adicionales. El análisis de los 3695 especímenes revela que el herbario está formado mayoritariamente (67,1%) por pliegos de intercambio obtenidos principalmente a través de la Société Helvétique pour l’Échange des Plantes y la Societat Botànica Barcelonesa. Entre los materiales estudiados se han localizado dos pliegos que consideramos interesantes desde un punto de vista taxonómico y/o nomenclatural (isótipos de Silene holzmanii Heldr. ex Boiss. y de Arenaria minutiflora Loscos). El interés principal del herbario radica, pues, en la gran diversidad de procedencias geográficas de las plantas, que hacen de esta colección uno de los primeros «herbarios europeos» de Cataluña. [ca] L’herbari BC-Trèmols fou creat durant la segona meitat del segle XIX pel químic i botànic català Frederic Trèmols i Borrell. Entre 1930 i 1960, el tècnic Antoni Marcos va fer-ne una profunda revisió. La col·lecció actual consta aproximadament d’uns 9000 plecs; està formada per 58 volums reordenats per Marcos, dos volums amb l’estructura original, quatre capses de Hieracium i 85 capses de material addicional. Fins ara s’han informatitzat 22 dels volums i les quatre capses de Hieracium (3695 espècimens), s’ha realitzat un inventari a nivell de gènere de tots els volums i s’ha informatitzat el catàleg original de l’herbari i el fitxer taxonòmic existent. També s’ha elaborat un inventari preliminar del contingut de les capses addicionals. L’anàlisi dels 3695 espècimens fa evident que l’herbari està format majoritàriament (67,1%) per plecs d’intercanvi obtinguts sobretot mitjançant la Société Helvétique pour l’Échange des i la Societat Botànica Barcelonesa. Entre els materials estudiats s’han trobat dos plecs que considerem interessants des d’un punt de vista taxonòmic i/o nomenclatural (isotipus de Silene holzmanii Heldr. ex Boiss. i d’Arenaria minutiflora Loscos). L’interès principal de l’herbari, doncs, rau en la gran diversitat de procedències geogràfiques de les plantes, que fan d’aquesta col·lecció un dels primers «herbaris europeus» de Catalunya.

Osteogenic effect of local, long versus short term BMP-2 delivery from a novel SPU-PLGA-βTCP concentric system in a critical size defect in rats

A concentric delivery system, composed of the three biomaterials SPU, PLGA, and βTCP (segmented polyurethane, poly[lactic-co-glycolic acid], and β-tricalcium phosphate) was fabricated as an external, porous ring of βTCP with a pasty core of a new SPU, mixed with PLGA microspheres. The regenerative effects of two distinct doses of either immediately available or continuously released rhBMP-2 were evaluated in an 8mm, critical calvaria defect in rats. Protein dose and release kinetics affected material resorption rates and the progression of the regeneration process. Groups treated with the empty system alone or in conjunction with free rhBMP-2 did not respond. By contrast, after 12 weeks, approximately 20% and 60% of the defects implanted with systems loaded with 1.6 μg and 6.5 μg rhBMP-2, respectively were healed, with all the growth factor being released in the course of 6 weeks. The NMR, FTIR, GPC, DSC, and histological analyses showed that PLGA microsphere degradation occurred independently of the regenerative process. However, the resorption rate of the SPU and βTCP did depend on the regeneration process, which was governed by dose and release rate of rhBMP-2. Furthermore, the biocompatibility and high capacity of adaptation to the defect convert the herein proposed, new SPU polymer into a potential material for applications in tissue engineering and regenerative medicine.

Efficacy of ciprofloxacin implants in treating experimental osteomyelitis

Ciprofloxacin (CFX) implants containing poly(D,L-lactide) and calcium phosphates (tricalcium phosphate and hydroxyapatite) was evaluated in 50 rabbits in an experimental osteomyelitis model. Their femoral cavity was inoculated with Staphylococcus aureus. After 2 weeks, the infected focus was cleaned out and the delivery system implanted. The infection and subsequent response to treatment were evaluated by microbiological analysis, biochemical and hematological markers, body weight, temperature, clinical signs, X-rays, and histology. Infected bone cultures, treated with CFX implants, showed reduced bacterial growth against controls. All CFX was released within 6 weeks. All animals recovered within 4 weeks. Even 12 weeks after implantation, no recurrence of infection was observed. Serum C-reactive protein, platelet, and leukocyte levels increased in all animals before treatment, and 4 weeks after it were maintained or rose in control animals, while decreased to normal levels in treated ones. Body weight was characterized by pretreatment losses, then gains during recuperation, or further loss in untreated animals; with no significant intraindividual differences in body temperature. Body weight, leucocytes, platelets, and C-reactive protein turned out to be highly useful markers for monitoring this kind of infection and its treatment. CFX implants demonstrated to be an effective therapy for S. aureus bone infection. Their efficacy was also reflected in decreasing severity of clinical signs, nonprogress of radiological signs indicative of infection, and good integration into bone structure. Histological examination revealed repair, with new bone formation extending into implants.

Biodegradable implantable fluconazole delivery rods designed for the treatment of fungal osteomyelitis: influence of gamma sterilization

Fluconazole poly(D,L-lactic) acid (PLA) and poly(L-lactic) acid (L-PLA) implantable delivery rods were studied, in vitro and in vivo, as an alternative treatment of fungal osteomyelitis. Implantable rods loaded with 5% fluconazole (FLU) were prepared by the injection-molding method and sterilized by gamma-irradiation at a dose of 25 kGy. Loading efficiency, physical chemistry (high performance liquid chromatography, X-ray diffraction, gel permeation chromatography), and in vitro and in vivo release assays were performed to evaluate the novel delivery systems and the sterilization effect on implant characteristics. In spite of polymer degradation after gamma-irradiation, the loading efficiency, chemical stability, and crystallographic structure of FLU were not affected. In vivo studies were carried out in femoral bone marrow of rabbits. Approximately 85 and 80% of the total dose were released within 12 and 4 weeks from PLA and L-PLA rods, respectively. This showed a faster release rate of FLU in vivo than in vitro, showing almost zero-order kinetics from PLA rods.

Two-month ciprofloxacin implants for multibacterial bone infections

A ciprofloxacin implant formulation composed of 12% hydroxyapatite, 36% tricalcium phosphate, 12% poly(DL-lactide) (PLA) and 40% ciprofloxacin was characterized in vivo for use in treatment of multibacterial bone infection. After the implant was inserted in the femur of rabbits, approximately 90% of the total ciprofloxacin was released within 8 weeks, maintaining therapeutic levels in the femur and tibia. Throughout the femoral cortex and marrow these remained higher than the minimum inhibitory concentrations (MIC) against the most common pathogens causing osteomyelitis. Levels in tibia cortex were also above MIC for 6 weeks. The implant was characterized in terms of polymer degradation and morphological and crystallographic changes. X-ray analyses confirmed the osteoconductivity and biocompatibility of these materials. The sequential changes in the femur were those of a normal surgical trauma reaction followed by a repair process. All the results confirmed that ciprofloxacin release is limited by its low solubility, and that implant erosion and bone ingrowth into the implants enhance the antibiotic release.

PLA-PEG particles as nasal protein carriers: the influence of the particle size

Previous studies have shown that PLA-PEG nanoparticles (NP) are able to enhance the transport of the encapsulated model protein, tetanus toxoid (TT), across the rat nasal mucosa. The aim of this work was to study if the size of PLA-PEG particles affects the nasal transport of the encapsulated protein and, also, the potential contribution of blank nanoparticles to the transport of the free protein. To achieve this purpose, 125I-TT was encapsulated into PLA-PEG particles of different sizes (200 nm, 1.5, 5 and 10 microm) prepared by the water-in-oil-in-water solvent evaporation technique. Firstly, in order to investigate the carrier role of the particles, two series of either conscious or anaesthetized rats were nasally treated with 125I-TT-loaded NP, free 125I-TT, and a physical mixture of blank NP and free 125I-TT. Secondly, the influence of the particle size on the nasal transport of TT encapsulated into PLA-PEG particles was evaluated in conscious rats. The amount of radioactivity recovered in the blood compartment, lymph nodes and other relevant tissues was monitored for up to 24h. Finally, the nasal bioavailability of 125I-TT-loaded PLA-PEG NP was calculated. The results indicated that the use of anaesthesia enhances the transport of 125I-TT and that the physical presence of PLA-PEG NP does not affect the transport of the toxoid. In contrast, when TT was encapsulated into the particles its transport across the nasal mucosa of conscious rats was significantly enhanced. Furthermore, the efficacy of this transport was related to the particle size, reaching the most important transport for the smallest particle size. The intensity of this transport was also illustrated by the high nasal bioavailability of TT encapsulated into nanoparticles (200 nm) (F = 70-80%). These results led us to conclude that PLA-PEG NP can be accepted as nasal protein carriers for nasal administration.

PEG-PLA nanoparticles as carriers for nasal vaccine delivery

This report presents an overview of the potential of nanoparticles as nasal carriers for drug/vaccine administration. In addition, this report shows, for the first time, the efficacy of polylactic acid nanoparticles coated with a hydrophilic polyethyleneglycol coating (PEG-PLA nanoparticles) as carriers for the nasal transport of bioactive compounds. For this purpose, tetanus toxoid (TT), a high molecular weight protein (Mw 150,000 Da), was chosen as a model antigen and encapsulated in the PEG-PLA nano- and microparticles (200 nm and 1.5 microm respectively). These nanosystems were first characterized for their stability in the presence of lysozyme and also for their size, electrical charge, loading efficiency, in vitro release of antigenically active toxoid and afterwards, these formulations were administered intranasally to mice and the systemic and mucosal anti-tetanus responses were evaluated for up to 24 weeks. Additionally, PEG-PLA particles labeled with rhodamine 6G were administered intranasally to rats in order to visualize their interaction with the nasal mucosae by fluorescence microscopy. Their behavior was compared with that of the well known PLA nanoparticles (200 nm). The results showed that PLA nanoparticles suffered an immediate aggregation upon incubation with lysozyme, whereas the PEG-coated nanoparticles remained totally stable. The antibody levels elicited following i.n. administration of PEG-coated nanoparticles were significantly higher than those corresponding to PLA nanoparticles. Furthermore, PEG-PLA nanoparticles generated an increasing and a long lasting response. The qualitative fluorescence microscopy studies revealed that PEG-PLA particles are able to cross the rat nasal epithelium. These studies indicate that the PEG coating around the particles has a role in stabilizing PLA particles in mucosal fluids and that it facilitates the transport of the nanoencapsulated antigen, hence eliciting a high and long lasting immune response.

Ciprofloxacin implants for bone infection. In vitro-in vivo characterization

To elucidate the antibiotic release mechanism from implants composed of calcium phosphates (hydroxyapatite [HAP] and tricalcium phosphate [TCP]), 30 kDa poly(DL-lactide) (PLA-30) and ciprofloxacin (CFX), nine formulations were prepared. In vitro results show that the release rate decreased as compression load and PLA/phosphates ratio increased. In contrast, a slower percent release rate was observed with higher drug loading. Swelling-erosion-disintegration of the implants was observed during the release assays, due to CFX swelling. Two CFX implant formulations were selected for implantation in the femur of rabbits, according to in vitro results. The implant drug loads tested were 10% and 40% of CFX. The in vivo results showed that the antibiotic concentrations achieved throughout the femur were higher for 4 weeks than the minimum inhibitory concentrations (MIC) against the most common of the pathogens that cause osteomyelitis. The CFX-10% implant was considered the best formulation as CFX was totally released within 6 weeks, and therapeutic bone levels were achieved, and the histological and radiographic analyses showed the osteoconductive properties of the materials. All these results showed that CFX release is limited by its solubility, and the erosion-disintegration and bone ingrowth into the implants enhanced the antibiotic release.

In vivo-in vitro study of biodegradable and osteointegrable gentamicin bone implants

Three implants composed of phosphate (25% hydroxyapatite, 75% tricalcium phosphate), 20% poly(DL-lactide) (DL-PLA; weight-average molecular weight (Mw), 30 kD) and 3% gentamicin sulphate (GS) were assayed in vitro and in vivo to study their release profiles as potential drug delivery systems to prevent or treat osteomyelitis. To prolong GS release, some implants were coated with poly(lactide-co-glycolide) (PLGA; Mw, 100 kD; I-PLGA) or DL-PLA (Mw, 200 kD; I-PLA). GS levels were measured in bone, kidney and blood after implantation into the femur of rats. The release profiles show a burst in the first few days, followed by a slower release rate. After I-PLA implantation, bone antibiotic concentrations higher than the minimum bactericidal concentration were maintained for 4 weeks. A linear correlation between in vitro and in vivo GS release was found to continue until complete drug release. Histological and radiological analysis showed that the implants were well tolerated and gradual new bone formation was observed.

Radiolabelled biodegradable microspheres for lung imaging

The effect on lung accumulation of modifying the surface compositions of (99m)Tc poly(lactide-co-glycolide) (PLGA) and (99m)Tc poly(ethylene glycol)-poly(lactide-co-glycolide) (PEG-PLGA) microspheres with different surfactants was assessed after intravenous injection into rats. Microspheres were prepared with PLGA or PEG-PLGA by the emulsion solvent evaporation method using polyvinyl alcohol (PVA), polyethylene glycol (PEG), albumin (BSA) or poloxamer 188 as surfactant, in the external aqueous phase. Commercial human albumin microspheres (Sferotec((R)), HAM) were used as reference. According to the European Pharmacopeia, >80% of (99m)Tc-HAM in the size range 10-50 microm, must be accumulated in the lung 15 min after intravenous administration. By modifying the surfactant, the resulting lung accumulation was 99% for (99m)Tc-HAM, and more than 50% for PLGA microspheres prepared with poloxamer 188 (1 and 4%), reaching 67% with 8% Poloxamer 188 and around 30-39% for PLGA and PEG-PLGA microspheres prepared with the other surfactants. PLGA microspheres made with 8% poloxamer 188 gave good quality lung images under a gamma camera for the first few minutes, subsequently liver radioactivity masked lung images.

Formulation of calcium phosphates/poly (d,l-lactide) blends containing gentamicin for bone implantation

Implants to prevent or treat osteomyelitis are described, composed of phosphate/poly(d,l-lactide) blends containing the antibiotic gentamicin. Seven formulations of implants containing 3% gentamicin sulfate (GS) were prepared at 433 MPa and 693 MPa of compression pressure. The blends contained phosphates (25% hydroxyapatite (HAP), 75% tricalcium phosphate (TCP)) and 20% dl-PLA (weight average molecular weight, M(w): 30 kD). To prolong GS release, implants were coated with PLGA (M(w):100 kD) or dl-PLA (M(w): 200 kD). Various durations of GS release from these devices were demonstrated as feasible. Release times of more than 10 weeks were attained with implants coated with dl-PLA (M(w): 200 kD), greatly exceeding the performance of the commercial formulation.

The Department of Defense laboratory-based global influenza surveillance system

Military global influenza surveillance began in 1976 as an Air Force program. In 1997, the Department of Defense (DoD) Global Emerging Infections Surveillance and Response System expanded the program to include all services. Also included were local residents in areas where DoD overseas research activities operated. This new, worldwide DoD surveillance infrastructure provides valuable information and can respond quickly to outbreaks. This was demonstrated during the current influenza season when a suspected outbreak was reported in Panama. In less than 3 weeks, specimens were collected, transported, and cultured, and isolates were subtyped and sent to the Centers for Disease Control and Prevention for further studies. This influenza surveillance initiative combines viral isolation, antigenic characterization, and molecular sequencing with clinical and public health management of information. The information obtained is shared with the Centers for Disease Control and Prevention and the World Health Organization and has contributed to important decisions in influenza vaccine composition.

Relating the phagocytosis of microparticles by alveolar macrophages to surface chemistry: the effect of 1,2-dipalmitoylphosphatidylcholine

This study examines the potential of 1,2-dipalmitoylphosphatidylcholine (DPPC), a major component of lung surfactant, to reduce the phagocytosis of microspheres by altering the cellular interactions occurring in the alveoli. These microspheres could be designed to act as a controlled delivery system for small molecules, peptides or proteins for pulmonary administration. Microspheres were prepared using poly (lactic-co-glycolic acid) (PLGA, 50/50 and encapsulated peroxidase as a model protein. DPPC was included in some formulations. The interaction of PLGA and DPPC-PLGA microspheres with phagocytic cells was evaluated using lung macrophages in culture. X-ray Photoelectron Spectra (XPS) results indicate that the inclusion of DPPC in the microspheres alters the microsphere surface chemistry, with the DPPC covering a large portion of the microsphere surface. The dominance of DPPC on the microsphere surface is highly beneficial in moderating the interaction occurring between the microspheres and phagocytic cells in the lung. Fluorescent confocal microscopy indicates that only 25% of cells internalized DPPC-coated particles, whereas 70% of those cells exposed to particles without the DPPC coating internalized particles after one hour of incubation.

The Adsorption of Poly(vinyl alcohol) to Biodegradable Microparticles Studied by X-Ray Photoelectron Spectroscopy (XPS)

The design of biodegradable microparticle drug delivery systems with precisely tailored surface properties requires surface analytical methods that can relate polymer chemistry and fabrication parameters to the final surface chemistry of the microparticles. We demonstrate using X-ray photoelectron spectroscopy (XPS) that it is possible to identify significant variations in the surface chemistry of microparticles composed of poly(lactic acid) (PLA), poly(lactide-co-glycolide) (PLGA), or block copolymers of PLA or PLGA with poly(ethylene glycol) (PEG). These variations are related to the mechanism by which the microparticle/water interface is stabilized. This, in turn, is controlled by the interfacial surface tensions of the polymers within aqueous environments. For PEG containing block copolymers, adsorption of a surfactant, poly(vinyl alcohol) (PVA), from the aqueous medium onto the polymer is reduced compared with the PLA and PLGA polymers. This reduction is achieved because the PEG segments, within the copolymer structure, stabilize the polymer/water interface. Estimates of the relative amounts of lactide, lactide-co-glycolide, vinyl alcohol, and ethylene glycol monomer units at the microparticle surfaces are presented based on curve-fitting analysis of the XPS data.