The Dependence on Smokeless Tobacco in the South Asian Communities in East London.

BACKGROUND & OBJECTIVE: The purpose of the study was to understand the dependency on smokeless tobacco. METHODS: The major aspect of the interview was to study the type of chewing tobacco used, frequency of purchase of chewing tobacco, change in attitude and behavior after the use of chewing tobacco. This study was done in 2005 in London. Of the 110 respondents interviewed 88 were used for the data analysis. STUDY DESIGN: An exploratory study was conducted in East London, United Kingdom. The selected sample was interviewed through a questionnaire, based on the Severson Smokeless Tobacco Dependence Scale. RESULTS: Cross tabulations report that in a sample of 88 South Asian UK resident men 46.6% used leaf (paan), 43.2% used processed form of chewing tobacco and 10.2% used gutka. Older age (67%) respondents were more likely than the younger age (30%) respondents to chew tobacco. The frequency of purchase of chewing tobacco is reported high (67.2%) in the older age group than the younger age group (50%). CONCLUSION: This current study used an amended form of the Severson Smokeless Tobacco Scale questionnaire to study the dependency on smokeless tobacco. The study could be developed in the selection of the sample, which would include both males and females to study the dependency on smokeless tobacco.

Usefulness of controlled release of growth factors in investigating the early events of dentin-pulp regeneration.

INTRODUCTION: Little information is yet available on the signals involved in progenitor cell migration that precede reparative dentin synthesis. Our aim was to investigate the effect of the controlled release of fibroblast growth factor (FGF)-2 and transforming growth factor ß1 (TGF-ß1) on permanent teeth pulp cell proliferation and progenitor cell migration. METHODS: FGF-2 and TGF-ß1 were encapsulated into a biodegradable polymer matrix of lactide and glycolide. Human pulp cells were prepared from third molars, and progenitor cells were sorted by STRO-1. The synthesized microsphere toxicity was checked with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test. The growth factor release kinetics were checked by an enzyme-linked immunosorbent assay while maintaining their biological activity and were evaluated by investigating their effects on pulp cell proliferation. Their chemotactic potential was investigated on STRO-1-sorted cells in a migration chamber on Matrigel (Cambrex Bio Science, Walkersville, MD). RESULTS: The cell viability was unaffected by the presence of microspheres. The released amount of FGF-2 and TGF-ß1 from the microspheres was maintained after 21 days. Increasing the FGF-2-loaded microsphere concentration or the release period significantly increased dental pulp cell proliferation. TGF-ß1 acted as a potent chemotactic factor of STRO-1-sorted cells. CONCLUSIONS: Encapsulating TGF-ß1 and FGF-2 in a biodegradable polymer of lactide and glycolide microsphere allowed a sustained release of growth factors and provided a protection to their biological activities. Our results clearly show the usefulness of growth factor controlled release in investigating the early events of pulp/dentin regeneration. It provides additional data on the signals required for vital pulp therapy and future tissue engineering.

Study of the effect of formulation parameters/variables to control the nanoencapsulation of hydrophilic drug via double emulsion technique.

Preparation of biodegradable nanoparticles containing active molecule is now taking much attention of researchers. The aim of the present work is to achieve the nanosize particles for the first time by double emulsion (W1/O/W2,) evaporation method to encapsulate hydrophilic substance using high performance stirring apparatus. A fluorescent stable hydrophilic agent (Stilbene derivative) was used as a model drug to be encapsulated. For this purpose, PCL (polycaprolactone) was chosen as polymer in this study. Several kinds of stabilizers [triton-405, tween 80, poloxamer, PVP (polyvinylpyrrolidone), PEG (poly ethylene glycol) & PVA (poly vinyl alcohol)] were investigated and the results indicate that the PVA (0.5% concentration) leads to the most stable double emulsion with the particle size in nano range. Different parameters affecting the size of particles have been studied such as stirring time (for 1st and 2nd emulsion), stirring speed (for 1st and 2nd emulsion), polymer and stabilizer concentrations etc. After duration of one month, the encapsulation efficiency of obtained particles was estimated using U.V. analysis. Transmission Electron Microscopy (TEM) showed that the prepared particles were spherical in shape. The size and size distribution were found to be submicron and ranging from 150 to 400 nm.

Controlled release carriers of growth factors FGF-2 and TGFbeta1: synthesis, characterization and kinetic modelling.

The purpose of this work is to produce microspheres loaded with transforming growth factor beta1 TGFbeta1 and basic fibroblast growth factor FGF-2; to ensure the protein protection from degradation during the encapsulation and storage steps, to evaluate the release rate and the microspheres toxicity. The water in oil in water double emulsion technique was adapted to avoid the protein degradation during the encapsulation. The obtained microspheres were deeply characterized to evaluate their size, morphology, toxicity, the way of degradation, the protein stability and release rate. The microspheres were found to be biocompatible and the encapsulation efficiency was about 35%. It was observed that the obtained microspheres increase the shelf life of the growth factors. The diffusion coefficient was quantified using Fick's law of diffusion that was combined to an empirical equation representing the decrease in the protein stability. Such modelling helped to give indirect information about the microspheres morphology and drug distribution within the microspheres. The main conclusion consists of the formation of a higher compact polymer matrix when smaller particles are produced, which has different distinct effects: the encapsulation efficiency and the stability of the encapsulated growth factor are enhanced while both the growth factor diffusion and the polymer degradation rates decrease.

Preparation conditions effect on the morphology and release kinetics of biodegradable particles: a mathematical approach.

Poly(lactic-co-glycolic acid) particles encapsulating albumin were produced by the double emulsion technique (Water in Oil in Water). The diffusion coefficient and therefore the release rate were quantified as a function of the operating conditions. The second Fick's law of diffusion was used by applying the entire particle size distribution to estimate the diffusion coefficient. The stirring speed, polyvinyl alcohol concentration in the external water phase and the water to oil ratio in the internal emulsion were varied. It was found that the release rate increased while decreasing the particle size. Therefore, all the process parameters that are assumed to affect the particles size--such as the stirring speed or marginally the polyvinyl alcohol concentration--are supposed to affect the release rate. Finally, decreasing the water to oil ratio in the internal emulsion was found to increase the particle porosity and therefore to increase the diffusion coefficient.