Growth hormone secretory in healthy aged women and men of Tunisian population

With aging, men and women experience multiple hormonal changes, and in particular the activity of the growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis. This perturbation may be involved inaggravations of numerous abnormalities. In 64 healthy elderly, we determined the concentrations of GH in both sexes and its correlation with thyroid-stimulating hormone (TSH), the descriptive data, BMI,electrolytic assessment and some biochemical parameters. Collected data suggest that there was an age-dependent decrease in GH secretion. For TSH, there was a slight increase. The simple regressionanalysis revealed non-significant direct relation between these two hormones. We also found that BMI values were inversely related to the serum concentrations of these hormones. For the lipid metabolism,the positively correlated relation only exists between GH and total-cholesterol, on one hand, and between GH and LDL-cholesterol, on the other. For the other parameters such as glucose and triglycerides as well as HDL-cholesterol, this relation does not exist. For the BMI, this index shows a positively correlated relation with glucose and triglycerides. The electrolytic assessment shows that inmen, phosphorus was positively related to GH. In women, calcium and sodium were positively related to GH. Aging was found to be associated with decreased morning serum GH levels and slightly increased TSH levels in healthy elderly Tunisian population. Reduction of the GH-IGF-I axis in the elderly has important clinical implications. Indeed, this deficiency in GH could contribute to the decline of various functions associated with normal aging

Antibacterial activity of Thymoquinone, an active principle of Nigella sativa and its potency to prevent bacterial biofilm formation

<p>Abstract</p> <p>Background</p> <p>Thymoquinone is an active principle of <it>Nigella sativa </it>seed known as "Habbah Al-Sauda" in Arabic countries and "Sinouj" in Tunisia. Bacterial biofilms tend to exhibit significant tolerance to antimicrobials drugs during infections.</p> <p>Methods</p> <p>The antibacterial activity of Thymoquinone (TQ) and its biofilm inhibition potencies were investigated on 11 human pathogenic bacteria. The growth and development of the biofilm were assessed using the crystal violet (CV) and the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay.</p> <p>Results</p> <p>TQ exhibited a significant bactericidal activity against the majority of the tested bacteria (MICs values ranged from 8 to 32 μg/ml) especially Gram positive cocci (<it>Staphylococcus aureus </it>ATCC 25923 and <it>Staphylococcus epidermidis </it>CIP 106510). Crystal violet assay demonstrated that the minimum biofilm inhibition concentration (BIC50) was reached with 22 and 60 μg/ml for <it>Staphylococcus aureus </it>ATCC 25923 and <it>Staphylococcus epidermidis </it>CIP 106510 respectively. In addition our data revealed that cells oxidative activity was influenced by TQ supplementation. In the same way, TQ prevented cell adhesion to glass slides surface.</p> <p>Conclusion</p> <p>The ability of TQ to prevent biofilm formation warrants further investigation to explore its use as bioactive substances with antibiofilm potential.</p

Lateral electrical transport, optical properties and photocurrent measurements in two-dimensional arrays of silicon nanocrystals embedded in SiO2

In this study we investigate the electronic transport, the optical properties, and photocurrent in two-dimensional arrays of silicon nanocrystals (Si NCs) embedded in silicon dioxide, grown on quartz and having sizes in the range between less than 2 and 20 nm. Electronic transport is determined by the collective effect of Coulomb blockade gaps in the Si NCs. Absorption spectra show the well-known upshift of the energy bandgap with decreasing NC size. Photocurrent follows the absorption spectra confirming that it is composed of photo-generated carriers within the Si NCs. In films containing Si NCs with sizes less than 2 nm, strong quantum confinement and exciton localization are observed, resulting in light emission and absence of photocurrent. Our results show that Si NCs are useful building blocks of photovoltaic devices for use as better absorbers than bulk Si in the visible and ultraviolet spectral range. However, when strong quantum confinement effects come into play, carrier transport is significantly reduced due to strong exciton localization and Coulomb blockade effects, thus leading to limited photocurrent

Evaluation de la contamination bactériologique du sol et des cultures irrigués par les eaux usées traitées

Nous avons essayé dans ce travail d'identifier les germes rencontrés dans les eaux usées à l'entrée et à la sortie des stations d'épuration dans le centre Tunisien et de suivre leur transmission en milieu agricole. Les espèces bactériennes identifiées à l'entrée et à la sortie de la station d'épuration ont été retrouvées au niveau du sol et des cultures irriguées par les eaux usées traitées. Il s'avère pue les cellules bactériennes survivent bien dans le sol, subissent des modifications biochimiques et se transmettent jusqu'au niveau des graines (Sorgho). Une large contamination fécale a été détectée au niveau des puits de surface et des cultures irriguées par les eaux usées traitées (épinard, luzerne)

Biological analysis and clinical phytotherapy of asthma in a population in Central Tunisia / Analyse biologique et phytoth\ue9rapie clinique de l\u27asthme dans une population de la tunisie centrale

Previous studies have reported that Asthma prevalence can reach 6.5% in the Tunisian population. Asthma morbidity is not only associated to the cost of the disease care but also to its highly increasing incidence among low-incomes populations. In this study, we investigated biological and molecular analysis of alpha 1 antitrypsin marker associated with asthma. A total of 96 asthmatic patients attending the pneumology services in central tunisian hospitals were analyzed. Alpha 1 antitrypsin phenotypes were determined by immunoturbidimetric quantification of plasma AAT and isoelectrofocusing of sera at pH 4-6 on polyacrylamide gel. Genotyping was performed by RFLP PCR. Mean plasma AAT level was 2.01\ub10.73 g/L. Allelic frequencies of the PiM1, PiM2, PiM3, PiS and PiZ AAT variants were 0.739, 0.229, 0.015, 0.01 and 0.005, respectively. On the other hand, a therapeutic measure survey for asthma was established. Treatmentapproach includes beta-2-mimetic, xanthic bases (theophylline) and corticoids administration during the disease evolutionary stage. However, it is generally held that this conventional treatments show various undesirable effects. Alternatively, Clinical Phytotherapy may be of benefit to the asthmatic patients. In fact, plants used in traditional medicine contain a wide range of ingredients that can be used to treat chronic as well as infectious diseases. Extracts from Tymus vulgaris, Lavandula officinalis, Satirrea montana, Ribes nigrum, Eucalyptus globulus are the most effective in asthma phytotherapy. The most important biological functions of the bioactive compounds of these plants are their anti-infectious effects. Plantago major, Fumaria officinalis are also of interest because of their antiallergic and choleritic properties