Antioxidant and antimicrobial proprieties of chitin and chitosan extracted from Parapenaeus Longirostris shrimp shell waste.

INTRODUCTION: Chitosan, the linear polymer, is produced by alkali deacetylation of chitin (CHI). Recently chitin and chitosan were attracted marked interest due to their biocompatibility, biodegradability and non-toxicity. MATERIALS AND METHODS: In this study, chitin was extracted from shrimp shell (Parapenaeus longirostris) and chitosan was deacetylated by classical and ultrasound-assisted method. The identification of functional groups and the determination of degree of deacetylation of chitin (CHI), classical deacetylated chitosan (CDC) and ultrasound-assisted deacetylated chitosan (UDC) were carried through Fourier Transform-Infrared Spectroscopy. Their antimicrobial and antioxidant activity were also investigated. RESULTS: The degree of deacetylation of CHI, CDC and UDC is 33.64%, 73.68% and 83.55%, respectively. Results showed that CHI, CDC and UDC exhibited a good antimicrobial activity against (S. aureus, E. coli, P. aeruginosa, K. pneumonia) and (C. albicans and C. parapsilosis). The scavenging ability of CHI, CDC and UDC on 1,1-diphenyl-2-picrylhydrazyl radicals is ranging from 4.71% to 21.25%, 11.45% to 32.78% and 18.27% to 44.17%, respectively, at the concentrations of 0.25 to 1mg/mL. The inhibition of lipid peroxidation with thiobarbituric acid-reacting substances is ranging from 11.7% to 51.63%, 17.24% to 63.52% and 29.31% to 77.39%, respectively, at varying concentrations of 0.25 to 1mg/mL. CONCLUSION: The effectiveness of CHI, CDC and UDC is correlated with their degree of deacetylation. The results indicate the possibility of exploiting chitin and chitosan as antimicrobial agent.

[Pulmonary function in rheumatoid arthritis in a Tunisian population]. / La fonction respiratioire dans la polyarthrite rhumatoïde chez une population tunisienne.

BACKGROUND: The rheumatoid polyarthritis (PR) is a frequent pathology in Tunisia. The most frequent extra articular expression of this disease is in the respiratory tract. AIM: To determine the lung functional profile of PR of the Tunisian population by establishing possible relations between ventilatory variables and clinico-biological parameters of PR. METHODS: It is a cross sectional study which concerned 87 patients (77 women) having a confirmed PR. They benefited from a measure of the lung function by a total physical Pléthysmography and by the technique of double transfer NO-CO. Clinical and biological checkup were realized. RESULTS: Three kinds of pulmonary function defects were found: obstructive ventilatory defect (13%), restrictive defect (7%) and mixed defect (1%). Ventilatory flows and the lung volumes correlated negatively with the inflammatory syndrome (p<0.05). Alveolar-capillary diffusion capacity (DLco) was altered in an isolated way or associated with the respiratory functional syndromes (obstructive and restrictive) (6%). This abnormality had a vascular origin with an isolated fall of the lung capillary volume (Vc), a membrane origin with an isolated fall of the diffusion membrane (DM) or a combined origin with the decline of Vc and DM. This latter case was found at a late stage of PR. 58% of PR patients had a normal pulmonary function. CONCLUSION: All these functional findings were linked to PR itself (inflammatory and auto-immune origin) or to the lung toxicity due to the treatment by Methotrexate (alveolar and bronchial damage).

Obesity induced bronchopulmonary hyperresponsiveness in Tunisian women.

OBJECTIVE: The specific objective of this investigation was to determine whether bronchopulmonary responsiveness (BPR) to methacholine (MCH) was associated with the body mass index (BMI) of Tunisian women. SUBJECTS: In all, 160 healthy nonsmoker women (52 lean, 45 overweight and 63 obese) were recruited and examined in the Clinical Laboratory of Physiology located in the Medical School of Sousse. The average ages (+/-s.e.) of the three categories of lean, overweight and obese subjects were 27.7+/-1.1, 33.2+/-1.7 and 37.5+/-1.3 years, respectively. Their corresponding mean BMIs (+/-s.e.) were 21.9+/-0.3, 27.7+/-0.2 and 36.5+/-0.8 kg m(-2), respectively. MEASUREMENTS: Before their inclusion into the study, subjects were screened for their lung status by measuring their pulmonary function testing parameters using a whole body plethysmograph. BPR was assessed, using a cumulative concentration response curve technique, by measuring with a spirometer the decrease in forced expiratory volume in 1 s (FEV(1)) in response to a cumulative dose of MCH. RESULTS: After adjusting for age, significant differences in both FEV(1) and forced vital capacity (VC) were found between the obese and lean groups (P<0.01), as well as between the obese and overweight groups (P<0.01). In addition, forced expiratory flow between 25 and 75% of VC was significantly different between the obese and lean groups (P<0.001), as well as between the lean and overweight groups (P=0.015). The mean maximum fall of FEV(1) in response to MCH challenge was significantly higher for the obese group (12.0%) than for the overweight (9.8%) or the lean (6.6%) group (P<0.01). Furthermore, the efficacy of the MCH agonist promoting the maximal response (E(max)) and its potency or effective dose producing 50% of the maximal response (ED(50)) were both associated with BMI (the higher the BMI, the higher the E(max) and the lower the ED(50)). CONCLUSION: Our data clearly show that obesity affects pulmonary function performance in Tunisian women by potentially promoting their bronchial hyperreactivity as suggested by the significant correlation between their BMI and the efficacy of the MCH, as well as its potency.

[Which definition to use when defining airflow obstruction?]. / Quelle définition faut-il choisir pour le déficit ventilatoire obstructif?

INTRODUCTION: There is no clear consensus as to what constitutes an obstructive ventilatory defect (OVD). According to the American Thoracic Society and European Respiratory Society, it is defined as being when the ratio of the forced expiratory volume (FEV1) and the slow expiratory vital capacity (VC) is below the lower limit of normal (LLN). According to the Global initiative for chronic Obstructive Lung Disease and the British Thoracic Society, it is an FEV1/forced expiratory vital capacity (FVC)<0.70 and an FEV1<80%. In addition, in daily practice, the OVD is diagnosed by a "Fixed ratio" FEV1/FVC<0.70 or

[Which definition to use when defining reversibility of airway obstruction?]. / Quelle définition faut-il choisir pour la réversibilité de l'obstruction bronchique?

INTRODUCTION: There is no clear consensus about what constitutes reversibility of airway obstruction. European Respiratory Society (ERS): Increase in FEV1 and/or FVC>12% of their theoretical value and>0.2l. British Thoracic Society: FEV1>15% of initial value and FEV1>0.2l. Global Initiative for Chronic Obstructive Lung Disease: Increase in FEV1>12% and>0.2l. Australia and New Zealand Thoracic Society: Increase in FEV1 >15%. American Thoracic Society/ERS: Increase in FEV1>12% and>0.2l or increase in FVC>12% and 0.2l. Our principal objective was to determine the percentage of patients with COPD (n=62) who were significant responders to the reversibility test according to the 5 recommendations. METHODS: Plethysmography was performed before and 15 minutes after inhalation of 400 micrograms of a short acting bronchodilator (BD). COPD is defined as a FEV1/FVC post BD<0.7. RESULTS: The percentage of responders varied from 24% to 50% depending on the recommendations used. CONCLUSION: Reversibility of airway obstruction is recommendation dependent.

[Aging of the lung parenchyma]. / Vieillissement du poumon profond.

INTRODUCTION: The study of lung parenchymal function is focused on the measurement of carbon monoxide diffusing transfer (TLCO) which is a function of both membrane characteristics (Dm) and capillary lung volume (Vc) The objective of this study was to estimate the effect of age on both variables. METHODS: At rest, 134 healthy non-smokers (18-85 year old) were investigated by a double transfer NO-CO method. Capillary pulmonary compliance was estimated by applying a continuous negative pressure (CNP: -10 mmHg) at the mouth to 24 subjects. RESULTS: Significant decreases in VA, TLCO, TLNO, Dm and Vc in relation to age were observed (p < 0.05). CNP induced a significant increase in all variables, the increase in Vc in elderly was greater than that in younger subjects. CONCLUSION: Alveolo capillary membrane aging induces a decrease in Dm and Vc, however the increase in the estimated capillary compliance with CNP could provide an adaptation to the decrease in Vc.

[Physiological factors influencing pulmonary capillary volume and membrane diffusion]. / Facteurs physiologiques influençant le volume capillaire pulmonaire et la diffusion membranaire.

BACKGROUND: The lung is subject to many physiological changes during life. The aim of this study was to identify factors that influence gas transfer, which depends on membrane diffusion (Dm) and pulmonary capillary blood volume (Vc). METHODS: Dm and Vc measurements were performed at rest in 135 healthy patients divided into three groups according to age and after an exercise in 22 non-trained children. Measurements were made using a simultaneous transfer of 2 gases; nitric oxide (NO) and carbon monoxide (CO). RESULTS: Dm was correlated with height in the adult group and with weight in the elderly group. Vc was not correlated with weight in the three studied groups, but correlated with height in the adult group. Dm and Vc declined with age (p<0.05), For Dm this started at the age of forty whereas a fall in Vc was apparent at sixty. Pulmonary and vascular ageing could explain these results. Sex had no effect on Dm and Vc. Exercise led to a significant rise in Dm and Vc (p<0.05) which was attributed to pulmonary capillary distension and recruitment. CONCLUSION: Knowledge of these physiological changes permits a better understanding of pathological changes.

[Physiological aspects of the decline of pulmonary function with age]. / Aspects physiologiques du vieillissement respiratoire.

After peaking between the age of 20 and 30 years, pulmonary function declines gradually with age. This decline is related to changes in respiratory dynamics (lung mechanics, gas exchange) and also to non-respiratory factors (e.g. changes in the immune system). This age-related fall in pulmonary function is not linear, for example there is no further decline in mean PaO(2) in men and women, nor in the FEV1/FVC ratio in men, after the age of 70 years. Caution is required when interpreting changes in pulmonary mechanics in the elderly due to greater variability of reference values in this age group.

[Physiological aspects of the decline of pulmonary function with age]. / Aspects physiologiques du vieillissement respiratoire.

After peaking between the age of 20 and 30 years, pulmonary function declines gradually with age. This decline is related to changes in respiratory dynamics (lung mechanics, gas exchange) and also to non-respiratory factors (e.g. changes in the immune system). This age-related fall in pulmonary function is not linear, for example there is no further decline in mean PaO2 in men and women, nor in the FEV1/FVC ratio in men, afterthe age of 70 years. Caution is required when interpreting changes in pulmonary mechanics in the elderly due to greater variability of reference values in this age group.

[Vital capacity and peak expiratory flow rates in a North-African population aged 60 years and over: influence of anthropometric data and parity]. / Capacité vitale et débits maximaux expiratoires dans une population nord-africaine âgée de plus de 60 ans: influence des données anthropométriques et de la parité.

INTRODUCTION: The aims of this study were to calculate predictive equations for respiratory variables (FVC, FEV1, FEF25%-75%, and PEFR) in elderly north-African people and to study the effect of parity on the respiratory function. METHODS: FVC and forced expiratory flows were measured in a "healthy" sample of 186 subjects aged 60 years and over (66% women). The measurements were made in health centres using portable spirometers. Predictive equations were determined by the technique of multiple linear regression using standing height and age as independent variables. The effect of parity on ventilatory function was studied by comparing two groups defined by a parity greater or less than 4. RESULTS: The respiratory variables measured in this elderly north-african population were significantly different from those established references ranges. CONCLUSIONS: High parity is associated with a significant reduction in peak flow rate.

[The importance of lung volumes in the investigation of heavy smokers]. / Place de la distension pulmonaire dans l'exploration des gros fumeurs de cigarettes.

INTRODUCTION: Lung hyperinflation (LH) has become a major concern in the management of chronic obstructive pulmonary disease (COPD). MAIN AIM: To evaluate the role of lung volumes in the positive diagnosis of COPD and in the assessment of airway obstruction reversibility. POPULATION AND METHODS: Three hundred and sixty-six male smokers over the age of 35 with more than 40 pack-years exposure were included in the study. Plethysmographic data were determined before/after taking a bronchodilator (BBD, ABD). Applied definitions: airflow obstruction: BBD FEV1/FVC<0.70. LH: BBD residual volume (RV)>upper limit of normal. Expressions of reversibility: Δvariable=(ABD-BBD) values; Δinit%=Δvariable/BBD value and Δref%=Δvariable/reference value. A 12%init and a 0.2L increase in either FEV1 or FVC or a 10%ref or - 300 mL decrease in RV were considered as clinically significant. RESULTS: Over the 85 smokers without airflow obstruction, 68% had LH. In the hyperinflated group (n=314), and compared to changes in FEV1 and FVC, these RV changes detected more respondents (54% for FEV1 and FVC vs. 65% for RV, P=0.002). This was not the case for the group free from LH (n=52) (23% for FEV1 and FVC vs. 35% for RV, P=0.09). In the 58 hyperinflated groups free from airflow obstruction, and compared to changes in FEV1 and FVC, changes in RV detected more respondents (24% for FEV1 and FVC vs. 71% for RV, P=0.0001). CONCLUSION: In heavy smokers, it seems essential to include LH as a criterion for a positive diagnosis of COPD and of reversibility evaluation.