Anti-Helicobacter pylori activities of six Iranian plants

BACKGROUND: Helicobacter pylori is the major worldwide cause of bacterial gastrointestinal infections in adults and children. Antibiotic therapy and a combination of two or three drugs have been widely used to eradicate these infections. However, development of drug resistance in bacteria calls for new sources of drugs, and plants seem to be a logical source of new antibacterial compounds. METHODS: The anti-H. pylori activities of six native Iranian plants (Glycyrrhiza aspera, Juglans regia, Ligustrum vulgare, Thymus kotschyanus, Trachyspermum copticum and Xanthium brasilicum) and seven antibiotics were determined against 70 clinical isolates from children using the disk susceptibility assay. Minimum inhibitory concentrations were also measured for the biologically active extracts. One extract with the best anti-H. pylori activity was fractionated by silica gel and thin layer chromatography and the active compounds were identified by hydrogen nuclear magnetic resonance ((1)HNMR) spectroscopy. RESULTS: All plant extracts showed anti-H. pylori activity by the disk sensitivity method, but the most active extracts were those from X. brasilicum and T. copticum. In fact, the anti-H. pylori activities of the two extracts were superior to the disk antibiotic susceptibility profile. Minimum inhibitory concentrations were within the range of 31.25-250 micro g/ml. Fractionation and chemical identification of the extract from X. brasilicum showed the presence of two substances, a flavonoid and a xanthanolide. CONCLUSIONS: Due to the rise in antibiotic resistance, new sources of anti-H. pylori drugs are needed. The use of medicinal plants and/or their chemical components may have potential benefit in eradicating such problems.     

Biomimetic synthesis and characterization of cobalt nanoparticles using apoferritin, and investigation of direct electron transfer of Co(NPs)–ferritin at modified glassy carbon electrode to design a novel nanobiosensor

Oxyhydroxy cobalt CoO(OH) nanoparticles (Co-NPs) were prepared in horse spleen apoferritin (HsAFr) cavity. Transmission electron microscopy revealed the particle size was 5.5-6 nm. Mineralization effect on HsAFr was investigated by fluorescence and far-UV circular dichroism (far-UV CD) spectroscopies. The far-UV CD experiments indicated an increase in the α-helical content after mineralization. Intrinsic fluorescence data showed that mineralization acts as a quencher of HsAFr. For the first time, direct electron transfer between Co(NPs)-HsAFr and a glassy carbon electrode in the thin film of dihexadecylphosphate (DHP) was investigated by cyclic voltammetry (CV) to design a biosensor. The anionic surfactant DHP was used to achieve direct electron-transfer between Co(NPs)-HsAFr molecules and the GC electrode surface. CV result showed clearly a pair of well-defined and quasi-reversible redox peaks arise from Co(NPs)-HsAFr embedded in DHP film. This novel biosensor can be used in medical and industrial fields to detect different analytes.     

Identification and genetic characterization of metallo-beta-lactamase-producing strains of Pseudomonas aeruginosa in Tehran, Iran

Metallo-beta-lactamases (MBLs) are being reported with increasing frequency worldwide. The aim of this study was to investigate the prevalence of blalMP-1, blaVIM-1,2 and blaSPM-1 genes encoding metallo-beta-lactamases (MBLs) among a collection of Pseudomonas aeruginosa strains isolated from patients at different hospitals in Tehran and to trace the disseminated clones at these hospitals by pulsed field gel electrophoresis (PFGE). Susceptibility of 610 P aeruginosa to 14 different antibiotics was determined using disc diffusion method. Isolates showing resistance to imipenem and ceftazidime were subjected to micro broth dilution assay to determine their MIC values. The blaIMP-1, blaVIM-1, blaVIM-2, and blaSPM-1, genes were amplified by PCR. Isolates containing blaVIM-1 were analyzed by PFGE. Sixty-eight isolates were resistant to imipenem (MIC > or = 4 microg/ml) of which 16 isolates carried blaVIM-1 gene using PCR assay. No other MBL genes were detected in this study. Three different unrelated patterns were found for isolates containing blaVIM-1 gene by PFGE of which pattern A was predominant. All isolates were susceptible to colistin and polymixin B. blaVIM-1 was the main gene encoding MBL among the isolates of P aeruginosa in our study. Clonal spread of isolates containing blaVIM-1 had occurred at Tehran hospitals. However, heterogeneous clones also were involved in the outbreaks.     

The Influences of Chromium Supplementation on Metabolic Status in Patients with Type 2 Diabetes Mellitus and Coronary Heart Disease

Biological Trace Element Research - This investigation was conducted to determine the effects of chromium supplementation on metabolic status in diabetic patients with coronary heart disease (CHD)....     

The selective orexin 1 receptor antagonist SB-334867-A impairs acquisition and consolidation but not retrieval of spatial memory in Morris water maze

The novel neuropeptides orexin-A and orexin-B derive from a common 130-amino acid precursor molecule (prepro-orexin), are mainly localized to neurons within and around the lateral hypothalamus, and exhibit high affinity to the closely related G-Protein-coupled receptors orexin 1 and 2 receptor (OX1R, OX2R). Orexinergic neurons send their axons to the hippocampal formation (CA1, CA2 and dentate gyrus), which expresses OX1Rs. Recent studies have shown that central administration of orexin-A and orexin-B have effects on learning and memory but literature concerning the role of orexinergic system in cognition remains controversial. More recently, antagonists have been described. The most potent and selective is SB-334867-A, which has an affinity of 40 nM at OX1R which is at least 50-fold selective over OX2R. It is likely that the intracerebroventricular (i.c.v.) administration may block OX1Rs in many brain regions. Previously we have shown that intra-CA1 injection of SB-334867-A impairs acquisition, consolidation and retrieval of spatial memory in MWM task. In the present study, the effect of pre-training, post-training and pre-probe of trial intra-DG (dentate gyrus) administration of SB-334867-A (1.5, 3, 6 microg/0.5 microl) on acquisition, consolidation and retrieval in a single-day testing version of MWM (Morris water maze) task was examined. Our results show impaired acquisition and consolidation of MWM task for SB-334867-A as compared with the control group. However, SB-334867-A had no effect on retrieval in spatial memory. Also, this antagonist had no effect on escape latency of a non-spatial visual discrimination task. Therefore, it seems that endogenous orexin-A and orexin-B, through DG OX1Rs, play an important role in spatial learning and memory in the rat.     

Molecular analysis and antimicrobial susceptibility of methicillin resistant Staphylococcus aureus in one of the hospitals of Tehran University of Medical Sciences: high prevalence of sequence type 239 (ST239) clone

Methicillin-resistant Staphylococcus aureus (MRSA), particularly the multidrug-resistant clones, is an increasing worldwide problem. The average incidence rate of MRSA in Tehran was found to be over 40%. A total of 140 MRSA isolates obtained from patients attending a teaching hospital in Tehran, from May 2009 to December 2009, were included in this study. The antimicrobial susceptibility profile of MRSA isolates was determined by the agar disk diffusion method. Molecular analysis of MRSA strains was accomplished by Pulsed-Field Gel Electrophoresis (PFGE) and Multi-locus sequence typing (MLST). Detection of mecA gene was used to confirm resistance to methicillin among the MRSA isolates. All the MRSA isolates were susceptible to chloramphenicol, teicoplanin, tigecycline and vancomycin. All MRSAisolates were resistant to oxacillin, whilst 139 strains showed resistance against ciprofloxacin, erythromycin, gentamicin, tetracycline and trimethoprim-sulfamethoxazole. PFGE analysis of all the 140 MRSA isolates produced five distinct pulsotypes designated as pulsotypes A-E. Most of the isolates (n=132) were clustered into pulsotype A. The most prevalent sequence type (ST) was ST 239 (pulsotype A) found in 82% (37/45) of the tested isolates. The second most prevalent type was ST 1238 (pulsotypes B, C and D) found in 15% (7/45) of the isolates. The remaining type, ST 8 (pulsotype E) was found in a single isolate. The results of this study indicated that the MRSA clone ST 239 was a major clone in the selected university hospital of Tehran and that it was widely spread among the different wards as well as all the age groups of patients.