GIRLHOOD: RELATIONAL EXPERIENCES OF ADOLESCENT GIRLS AND GIRL IDENTITY

The purpose of this study was to explore relational experiences of adolescent girls within their peer culture, and their experiences and perceptions of girl identity. Participants were ten adolescent girls residing in a mid-sized Southern Ontario city, and they ranged between 13 and 16 years of age. Through semi-structured interviews, eight themes emerged and were compared with the available literature. These themes included the following: The “Drama” of Girl Culture, False-Self Behaviors, The Dark Underside of Girl Culture, Authenticity, Experiencing Difference and Individuality, Resistance, Friendship, and Breaking Down Barriers

GIRLHOOD: RELATIONAL EXPERIENCES OF ADOLESCENT GIRLS AND GIRL IDENTITY

The purpose of this study was to explore relational experiences of adolescent girls within their peer culture, and their experiences and perceptions of girl identity. Participants were ten adolescent girls residing in a mid-sized Southern Ontario city, and they ranged between 13 and 16 years of age. Through semi-structured interviews, eight themes emerged and were compared with the available literature. These themes included the following: The “Drama” of Girl Culture, False-Self Behaviors, The Dark Underside of Girl Culture, Authenticity, Experiencing Difference and Individuality, Resistance, Friendship, and Breaking Down Barrier

Interferon beta 1b following natalizumab discontinuation: one year, randomized, prospective, pilot trial

Background: Natalizumab (NTZ) discontinuation leads to multiple sclerosis reactivation. The objective of this study is to compare disease activity in MS patients who continued on NTZ treatment to those who were switched to subcutaneous interferon 1b (IFNB) treatment. Methods: 1-year randomized, rater-blinded, parallel-group, pilot study (ClinicalTrial.gov ID: NCT01144052). Relapsing remitting MS patients on NTZ for ≥12 months who had been free of disease activity on this therapy (no relapses and disability progression for ≥6 months, no gadolinium-enhancing lesions on baseline MRI) were randomized to NTZ or IFNB. Primary endpoint was time to first on-study relapse. Additional clinical, MRI and safety parameters were assessed. Analysis was based on intention to treat. Results: 19 patients (NTZ n=10; IFNB n=9) with similar baseline characteristics were included. 78% of IFNB treated patients remained relapse free (NTZ group: 100%), and 25% remained free of new T2 lesions (NTZ group: 62.5%). While time to first on-study relapse was not significantly different between groups (p=0.125), many secondary clinical and radiological endpoints (number of relapses, proportion of relapse free patients, number of new T2 lesions) showed a trend, or were significant (new T2 lesions at month 6) in favoring NTZ. Conclusions: De-escalation therapy from NTZ to IFNB over 1 year was associated with some clinical and radiological disease recurrence. Overall no major safety concerns were observed

Studying the release of hGH from gamma-irradiated PLGA microparticles using ATR-FTIR imaging

Attenuated total reflection-Fourier transform infrared (ATR-FTIR) imaging has been applied for the first time to monitor the redistribution and release of hGH from a range of PLGA/PLA microparticles during a set of dissolution experiments at 37 °C in D2O. The effect of gamma-irradiation, a common sterilisation method, on hGH release kinetics from such systems has been demonstrated. Increasing the gamma dose was shown to have a profound influence on the nature of the release mechanism, with higher gamma doses leading to a dramatic increase in the initial burst release followed by a retardation in the sustained release and a lower total level of hGH release over the dissolution experiment. These changes were shown to be the result of a combination of factors; firstly, via scanning electron microscopy (SEM), gamma-irradiation was shown to strongly influence the morphology of the PLGA/PLA microparticles; reducing their overall porosity and reducing the available surface area, whilst forcing some of the entrapped hGH to the microparticle surface. Secondly, from FTIR measurements, gamma-irradiation was shown to increase the number of oxygenated components in the Poloxamer 407 excipient, by a process of chain scission, thereby increasing the strength of interaction between the microparticle and the entrapped hGH

Investigation of factors influencing the hydrolytic degradation of single PLGA microparticles

Abstract Poly lactide-co-glycolide (PLGA) is an important polymer matrix used to provide sustained release across a range of active pharmaceutical ingredients (APIs) and works by hydrolytic degradation within the body, thereby releasing entrapped drug. Processing and sterilisation can impact on the morphology and chemistry of PLGA therefore influencing the hydrolysis rate and in turn the release rate of any entrapped API. This paper has looked at the effect of supercritical carbon dioxide (scCO2) processing, gamma irradiation, comonomer ratio and temperature on the hydrolysis of individual PLGA microparticles, using a combination of Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) imaging, Scanning Electron Microscopy (SEM), Differential Scanning Calorimetery (DSC) and Gel Permeation chromatography (GPC) to facilitate a better understanding of the physiochemical factors affecting the hydrolysis rate. This work has shown that scCO2 processing influences hydrolysis rates by increasing the porosity of the PLGA microparticles, increasing the lactide comonomer ratio decreases hydrolysis rates by reducing the hydrophilicity of the PLGA microparticles and increasing the gamma irradiation dose systematically increases the rate of hydrolysis due to reducing the overall molecular weight of the polymer matrix via a chain scission mechanism. Moreover this work shows that ATR-FTIR imaging facilitates the determination of a range of physicochemical parameters during the hydrolysis of a single PLGA microparticle including water ingress, water/polymer interface dimensions, degradation product distribution and hydrolysis rates for both lactide and glycolide copolymer units from the same experimen

Study of the influence of Beta-radiation on the properties and mineralization of different starch-based biomaterials

In this work, the effects of beta-radiation are assessed, for the first time, on starch-based biodegradable polymers, with the aim of using it as an alternative sterilization process to the previously studied sterilization methods. Different doses of radiation were used in order to investigate the possibility of using this sterilization technique as a treatment to tailor the surface and bulk properties (namely mechanical) of these polymers. The as-treated substrates were characterized by water-uptake measurements and contact angle (theta) measurements. The mechanical properties of the materials were characterized by tensile tests by means of ultimate tensile strength (UTS) and strain at break (epsilon). The fracture of the surfaces was observed by scanning electron microscopy (SEM). Dynamic mechanical analysis (DMA) was also used to characterize the viscolelastic behavior of the irradiated materials. The main effect of sterilization with beta-radiation over the starch-based polymers seems to be a surface modification by an increase of the hydrophilicity. Nevertheless, because beta-radiation did not significantly affect the mechanical properties, it can be regarded as an effective way of modifying the surface for applications were more hydrophilic surfaces are desirable

Sterilization of Exopolysaccharides Produced by Deep-Sea Bacteria: Impact on Their Stability and Degradation

Polysaccharides are highly heat-sensitive macromolecules, so high temperature treatments are greatly destructive and cause considerable damage, such as a great decrease in both viscosity and molecular weight of the polymer. The technical feasibility of the production of exopolysaccharides by deep-sea bacteria Vibrio diabolicus and Alteromonas infernus was previously demonstrated using a bioproduct manufacturing process. The objective of this study was to determine which sterilization method, other than heat sterilization, was the most appropriate for these marine exopolysaccharides and was in accordance with bioprocess engineering requirements. Chemical sterilization using low-temperature ethylene oxide and a mixture of ionized gases (plasmas) was compared to the sterilization methods using gamma and beta radiations. The changes to both the physical and chemical properties of the sterilized exopolysaccharides were analyzed. The use of ethylene oxide can be recommended for the sterilization of polysaccharides as a weak effect on both rheological and structural properties was observed. This low-temperature gas sterilizing process is very efficient, giving a good Sterility Assurance Level (SAL), and is also well suited to large-scale compound manufacturing in the pharmaceutical industry

Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations : design, characterisation, toxicity and transcorneal permeation studies

This study was aimed at preparing, characterising and evaluating in situ gel formulations based on a blend of two hydrophilic polymers i.e. poloxamer 407 (P407) and poloxamer 188 (P188) for a sustained ocular delivery of ketorolac tromethamine (KT). Drug-polymer interaction studies were performed using {DSC} and FT-IR. The gelation temperature (Tsol-gel), gelation time, rheological behaviour, mucoadhesive characteristics of these gels, transcorneal permeation and ocular irritation as well as toxicity was investigated. {DSC} and FT-IR studies revealed that there may be electrostatic interactions between the drug and the polymers used. {P188} modified the Tsol/gel of {P407} bringing it close to eye temperature (35°C) compared with the formulation containing {P407} alone. Moreover, gels that comprised {P407} and {P188} exhibited a pseudoplastic behaviour at different concentrations. Furthermore, mucoadhesion study using mucin discs showed that in situ gel formulations have good mucoadhesive characteristics upon increasing the concentration of P407. When comparing formulations {PP11} and PP12, the work of adhesion decreased significantly (P < 0.001) from 377.9 ± 7.79 mN.mm to 272.3 ± 6.11 mN.mm. In vitro release and ex vivo permeation experiments indicated that the in situ gels were able to prolong and control {KT} release as only 48 of the {KT} released within 12 h. In addition, the HET-CAM and {BCOP} tests confirmed the non-irritancy of {KT} loaded in situ gels, and HET-CAM test demonstrated the ability of ocular protection against strongly irritant substances. {MTT} assay on primary corneal epithelial cells revealed that in situ gel formulations loaded with {KT} showed reasonable and acceptable percent cell viability compared with control samples

Biomarkers of Multiple Sclerosis

The search for an ideal multiple sclerosis biomarker with good diagnostic value, prognostic reference and an impact on clinical outcome has yet to be realized and is still ongoing. The aim of this review is to establish an overview of the frequent biomarkers for multiple sclerosis that exist to date. The review summarizes the results obtained from electronic databases, as well as thorough manual searches. In this review the sources and methods of biomarkers extraction are described; in addition to the description of each biomarker, determination of the prognostic, diagnostic, disease monitoring and treatment response values besides clinical impact they might possess. We divided the biomarkers into three categories according to the achievement method: laboratory markers, genetic-immunogenetic markers and imaging markers. We have found two biomarkers at the time being considered the gold standard for MS diagnostics. Unfortunately, there does not exist a single solitary marker being able to present reliable diagnostic value, prognostic value, high sensitivity and specificity as well as clinical impact. We need more studies to find the best biomarker for MS.publishersversionPeer reviewe