Preliminary note on anti-insulin antibody formation in diabetics treated with porcine insulin

In the present study, we have tested the sera of sixty five diabetic patients treated with insulin, researching the action of some physiologic and therapeutic factors (sex, age, insulin dose and time of treatment), to production of anti-insulin antibodies. Our results have shown that an important percentage of diabetic patients treated by porcine insulin produce antibodies: 72% of studied patients, concerning chiefly all the women and patients under-fourty years old. However our results have not pointed out any relation between the administered insulin dose versus the anti-insulin antibodies production, in spite of the early production of these antibodies in a great part of the patients.     

Morphological and Chemical Differentiation between Tunisian Populations of Pinus halepensis,Pinus brutia,and Pinus pinaster

The lipid fraction of seeds from different pine species and populations was studied regarding total lipid content, fatty acid profile and vitamin E composition. The investigated seeds contained a high percentage of lipid (13.6 to 31.5 %). Lipid fractions were found to be rich in vitamin E, which varied significantly among species and populations. P. halepensis (Ph−Hn) showed the highest content of vitamin E (256.3 mg/kg of seeds) and the uppermost content of α-tocopherol (44 mg/kg). However, P. halepensis (Ph−Kas) was the richest in γ-tocopherol (204.9 mg/kg). Lipid fractions had a low content of δ-tocopherol (1.2 to 3.6 mg/kg. The highest content of γ-tocotrienol (∼18 %) was determined for P. halepensis (Ph−Dc and Ph−Hn). Thirteen fatty acids were identified by GC-FID with significant variation between the investigated species. The linoleic acid was the major fatty acid followed by oleic acid and palmitic acid. The chemical differentiation among species for the composition of fatty acids and vitamin E was confirmed by PCA. Significant correlations were observed between the content of vitamin E and fatty acids and ecological parameters of P. halepensis populations.     

Molecular characterization of methicillin-resistant Panton-valentine leukocidin positive <Emphasis Type="Italic">staphylococcus aureus</Emphasis> clones disseminating in Tunisian hospitals and in the community

Background

The spread of MRSA strains at hospitals as well as in the community are of great concern worldwide. We characterized the MRSA clones isolated at Tunisian hospitals and in the community by comparing them to those isolated in other countries.

Results

We characterized 69 MRSA strains isolated from two Tunisian university hospitals between the years 2004-2008. Twenty-two of 28 (79%) community-associated MRSA (CA-MRSA) strains and 21 of 41 (51%) healthcare-associated MRSA (HA-MRSA) strains were PVL-positive. The PVL-positive strains belonged to predicted founder group (FG) 80 in MLST and carried either type IVc SCCmec or nontypeable SCCmec that harbours the class B mec gene complex. In contrast, very diverse clones were identified in PVL-negative strains: three FGs (5, 15, and 22) for HA-MRSA strains and four FGs (5, 15, 45, and 80) for CA-MRSA strains; and these strains carried the SCCmec element of either type I, III, IVc or was nontypeable. The nucleotide sequencing of phi7401PVL lysogenized in a CA-MRSA strain JCSC7401, revealed that the phage was highly homologous to phiSA2mw, with nucleotide identities of more than 95%. Furthermore, all PVL positive strains were found to carry the same PVL phage, since these strains were positive in two PCR studies, identifying gene linkage between lukS and mtp (major tail protein) and the lysogeny region, both of which are in common with phi7401PVL and phiSa2mw.

Conclusions

Our experiments suggest that FG80 S. aureus strains have changed to be more virulent by acquiring phi7401PVL, and to be resistant to β-lactams by acquiring SCCmec elements. These novel clones might have disseminated in the Tunisian community as well as at the Tunisian hospitals by taking over existing MRSA clones.

     

Epigallocatechin-3-gallate up-regulates tumor suppressor gene expression via a reactive oxygen species-dependent down-regulation of UHRF1

Ubiquitin-like containing PHD and Ring finger 1 (UHRF1) contributes to silencing of tumor suppressor genes by recruiting DNA methyltransferase 1 (DNMT1) to their hemi-methylated promoters. Conversely, demethylation of these promoters has been ascribed to the natural anti-cancer drug, epigallocatechin-3-gallate (EGCG). The aim of the present study was to investigate whether the UHRF1/DNMT1 pair is an important target of EGCG action. Here, we show that EGCG down-regulates UHRF1 and DNMT1 expression in Jurkat cells, with subsequent up-regulation of p73 and p16^INK4A genes. The down-regulation of UHRF1 is dependent upon the generation of reactive oxygen species by EGCG. Up-regulation of p16^INK4A is strongly correlated with decreased promoter binding by UHRF1. UHRF1 over-expression counteracted EGCG-induced G1-arrested cells, apoptosis, and up-regulation of p16^INK4A and p73. Mutants of the Set and Ring Associated (SRA) domain of UHRF1 were unable to down-regulate p16^INK4A and p73, either in the presence or absence of EGCG. Our results show that down-regulation of UHRF1 is upstream to many cellular events, including G1 cell arrest, up-regulation of tumor suppressor genes and apoptosis.     

Synthesis and biological evaluation of 4,5-dihydro-1H-pyrazole derivatives as potential nNOS/iNOS selective inhibitors. Part 2: Influence of diverse substituents in both the phenyl moiety and the acyl group

In a preliminary article, we reported a series of 4,5-dihydro-1H-pyrazole derivatives as neuronal nitric oxide synthase (nNOS) inhibitors. Here we present the data about the inhibition of inducible nitric oxide synthase (iNOS) of these compounds. In general, we can confirm that these pyrazoles are nNOS selective inhibitors. In addition, taking these compounds as a reference, we have designed and synthesized a series of new derivatives by modification of the heterocycle in 1-position, and by introduction of electron-donating or electron-withdrawing substituents in the aromatic ring. These derivatives have been evaluated as nNOS and iNOS inhibitors in order to identify new compounds with improved activity and selectivity. Compound 3r, with three methoxy electron-donating groups in the phenyl moiety, is the most potent nNOS inhibitor, showing good selectivity nNOS/iNOS.     

Iron and nickel complexes with heterocyclic ligands: Stability,synthesis, spectral characterization,antimicrobial activity,acute and subacute toxicity

The synthesis and characterization by elemental analysis, emission atomic spectroscopy, TG measurements, magnetic measurements, FTIR, ¹H NMR, UV–visible spectra and conductivity of a series of iron (II) and nickel (II) complexes with two heterocyclic ligands (L¹(SMX): sulfamethoxazole and L²(MIZ): metronidazole) used in pharmaceutical field and with a new ligand derived benzoxazole (L³(MPBO): 2-(5-methylpyridine-2-yl)benzoxazole), were reported. The formulae obtained for the complexes are: [M(L¹)₂ Cl₂]·nH₂O, [M(L²)₂Cl₂(H₂O)₂]·H₂O and [M(L³)₂(OH)₂]·nH₂O. Stability constants of these complexes have been determined by potentiometric methods in water–ethanol (90:10, v/v) mixture at a 0.2 mol L^?1 ionic strength (NaCl) and at 25.0 ± 0.1 °C. Sirko program was used to determine the protonation constants as well as the binding constants of three species [ML₂H₂]²⁺, [ML₂] and [ML]²⁺. The antimicrobial activity of the ligands and complexes was evaluated in vitro against different human bacteria and fungi using agar diffusion method.Iron sulfamethoxazole complex showed a remarkable inhibition of bacteria growth especially on Staphylococcus aureus and P. aeruginosa. The iron metronidazole complex is active against yeasts especially on Candida tropicalis strain. Nickel complexes presented different antibacterial and antifungal behavior's against bacteria and fungal.The acute toxicity study revealed that the iron complexes are not toxic at 2000 mg/kg dose orally administrated.LD₅₀ for nickel complexes was determined using graphical method.No significant differences in the body weights between the control and the treated groups of both rat sexes in subacute toxicity study using for iron complexes. Hematological and clinical blood chemistry analysis revealed no toxicity effects of the iron complexes. Pathologically, neither gross abnormalities nor histopathological changes were observed for these complexes.     

Genetic diversity of Colletotrichum gloeosporioides species complex associated with Citrus wither‐tip of twigs in Tunisia using microsatellite markers

Anthracnose Citrus disease has been associated with several symptoms worldwide and it is recently compromising Citrus production in the Mediterranean area. Four species complexes are mainly involved: Colletotrichum boninense, C. acutatum, C. gloeosporioides and C. truncatum. In this study, we investigated the genetic diversity of Colletotrichum spp. in Tunisia associated with wither‐tip of twigs on Citrus. Specific primers ITS4‐CgInt allowed the identification of C. gloeosporioides species complex in all the 54 isolates, sampled from three regions and four Citrus species. Overall, our genotypic analysis using 10 SSR markers showed a moderate diversity level in Tunisian C. gloeosporioides population and highlighted that C. gloeosporioides reproduce mainly clonally. In addition, heterothallic isolates were present in our population, suggesting that the pathogen population may undergo parasexual recombinations. The highest genetic diversity in C. gloeosporioides was recorded in Nabeul and on orange, which likely constitutes the area and the host of origin for the Citrus anthracnose disease in Tunisia. In addition, no population subdivision was detected at the geographic, host species or cultivars’ origin levels. However, our study identified two genetic subpopulations and indicated a rapid C. gloeosporioides population change at temporal scale that should be further examined over several consecutive growing seasons in order to understand its population dynamics.     

MHC class I recognition by NK receptors in the Ly49 family is strongly influenced by the beta 2-microglobulin subunit

NK cell recognition of targets is strongly affected by MHC class I specific receptors. The recently published structure of the inhibitory receptor Ly49A in complex with H-2Dd revealed two distinct sites of interaction in the crystal. One of these involves the alpha1, alpha2, alpha3, and beta2-microglobulin (beta2m) domains of the MHC class I complex. The data from the structure, together with discrepancies in earlier studies using MHC class I tetramers, prompted us to study the role of the beta2m subunit in MHC class I-Ly49 interactions. Here we provide, to our knowledge, the first direct evidence that residues in the beta2m subunit affect binding of MHC class I molecules to Ly49 receptors. A change from murine beta2m to human beta2m in three different MHC class I molecules, H-2Db, H-2Kb, and H-2Dd, resulted in a loss of binding to the receptors Ly49A and Ly49C. Analysis of the amino acids involved in the binding of Ly49A to H-2Dd in the published crystal structure, and differing between the mouse and the human beta2m, suggests the cluster formed by residues Lys3, Thr4, Thr28, and Gln29, as a potentially important domain for the Ly49A-H-2Dd interaction. Another possibility is that the change of beta2m indirectly affects the conformation of distal parts of the MHC class I molecule, including the alpha1 and alpha2 domains of the heavy chain.     

Serotype Distribution,Antibiotic Resistance and Clonality of Streptococcus pneumoniae Isolated from Immunocompromised Patients in Tunisia

BackgroundPneumococcal disease, a major cause of morbidity and mortality globally, has higher incidence among young children, the elderly and the immunocompromised of all ages. In Tunisia, pneumococcal conjugate vaccines (PCVs) are not included in the national immunization program. Also, few studies have described the epidemiology of S. pneumoniae in this country and, in particular, no molecular typing studies have been performed. The aim of this study was to evaluate serotype distribution, antimicrobial resistance and clonality of Streptococcus pneumoniae isolated from neutropenic patients in Tunisia.MethodsFifty-nine S. pneumoniae were isolated from infection (n = 31) and colonization (n = 28) sites of patients (children and adults) attending the National Centre of Bone Marrow Transplantation in Tunis between 2005–2011. All isolates were characterized by serotype, antimicrobial resistance pattern and multilocus sequence typing (MLST).ResultsThe majority (66.1%) of the isolates belonged to five serotypes all included in PCVs: 6B, 9V, 14, 19F and 23F. The potential coverage of the 10-valent and 13-valent PCV was of 71.2% and 76.3% respectively. Resistance rates were very high and 69.5% of the isolates were multidrug resistant: non-susceptibility rates to penicillin, amoxicillin and cefotaxime were 66.1%, 40.7% and 27.1%, respectively; resistance rates to erythromycin, clindamycin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole, were 69.5%, 61.0%, 37.3%, 22.0% and 67.8%, respectively. The most frequent serotypes had STs characteristic of multidrug resistant international clones known to be highly successful and important causes of pneumococcal infection: Spain 23F-ST81, France 9V/14-ST156, Spain 6B-ST90, 19F-ST320, and Portugal 19F-ST177.ConclusionsThe majority of S. pneumoniae strains recovered from immunocompromised patients in Tunisia are representatives of multidrug resistant pandemic clones that express serotypes targeted by PCVs. To contain the burden of pneumococcal disease and improve treatment choices among Tunisian immunocompromised patients PCVs should be offered to all of them.