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Copolyesters based on glycolic acid (G) combined with adipic acid (A) and ethylene glycol (E) were synthesized in different percentage of molar ratios (A: 100–50% and G: 100%) and their hydrolytic degradation was studied and correlated with their structures. According to the DSC, the production of polyesters leads to the formation of copolyesters and not to mixtures of homopolyesters. The crystallites in the copolyesters mainly consist of continuous sequences of ethylene adipate structural units. The hydrolytic degradation of the polyesters was followed by their weight loss during hydrolysis and by the FTIR spectra of the initial polyesters compared with that of the degraded polyesters at equilibrium. The region between 1142 and 800 cm −1 can be utilized to evaluate the extent of degradation of polyesters after their hydrolysis. The absorption bands at 1142, 1077 and 850 cm −1 due to the amorphous region decrease after hydrolysis, whereas those at 972, 901 and 806 cm −1 due to the crystalline region increase. The experimental data of the hydrolytic degradation were fitted with exponential rise to maximum type functions using two-parameter model, which describes very well mainly the initial part of the degradation, and four-parameter model (containing two exponential terms), which is appropriate for fitting the hydrolytic degradation on the entire time period (including the equilibrium). Furthermore, the kinetics of the hydrolytic degradation of the polyesters for the initial time period based on both models results to similar values of the rate constant, k. The synthesized copolyesters of glycolic acid combined with adipic acid and ethylene glycol are soluble in many common organic solvents opposite to PGA, leading to modified biodegradable polyesters and therefore they can be easily processed.

Background: The prevalence of asthma and wheezing has risen during the past four decades. Recent reports suggest that the “asthma epidemic” has reached a plateau. Objective: To examine further trends in the prevalence of childhood diagnosed asthma and wheezing in an urban environment in Greece. Methods: A population-based cross-sectional parental questionnaire survey was repeated among third-grade and fourth-grade school children (8–10 years) of public primary schools in 2003 in the city of Patras, Greece, by using methods identical to that of surveys conducted in 1978 (completed questionnaires, n = 3003), 1991 (n = 2417) and 1998 (n = 3076). Results: 2725 questionnaires were completed in the 2003 survey. The prevalence rates of current asthma and/or wheezing in 1978, 1991, 1998 and 2003 were 1.5%, 4.6%, 6% and 6.9%, respectively (p for trend <0.001). The lifetime prevalence of asthma and/or wheezing in the three more recent surveys was 8%, 9.6% and 12.4%, respectively (p for trend <0.001). The male:female ratios of current asthma and/or wheezing in the four surveys were 1.14:1, 1.15:1, 1.16:1 and 1.22:1, respectively. The proportion of those with wheezing diagnosed with asthma has increased during the study period, more so among non-current children with asthma. Conclusions: Our findings show a continuous increase in the prevalence of asthma and wheezing among preadolescent children in Patras, Greece, over 25 years, albeit at a decelerating rate. There seems to be a true increase in wheezing, despite some diagnostic transfer, particularly among younger children. The male predominance of the disease has persisted in the population of this study.

BACKGROUND The aim of the present study was to compare the prevalence of asthma among schoolchildren in 1978, 1991, and 1998 in Patras, Greece. METHODS The study populations of the three comparable cross sectional surveys comprised third and fourth grade public school children in Patras, Greece. Sample sizes in 1978, 1991, and 1998 were 3735, 2952 and 3397 children and response rates were 80.4%, 81.9%, and 90.6%, respectively. Prevalence of current, non-current, and lifetime asthma or recurrent wheezing was determined by parental questionnaire. Personal communication with the parents of asthmatic children in 1991 and 1998 provided data on lost schooldays. RESULTS Prevalence rates of current asthma or wheezing in 1978, 1991, and 1998 were 1.5%, 4.6%, and 6.0%, respectively (1978–91: p=0.01, 1991–98: p=0.02, 1978–98: p=0.03). Lifetime prevalences of asthma or wheezing in 1991 and 1998 were 8.0% and 9.6%, respectively (p=0.03). Current diagnosed asthma increased proportionally to diagnosed wheezing during 1991–98. The number of schooldays lost in the previous 2 years because of asthma did not change (p>0.1) between 1991 (0.31 per child) and 1998 (0.34 per child). CONCLUSIONS Our results support a true increase in the prevalence of current and lifetime asthma in the last 20 years among pre-adolescent children in Patras, Greece.