Current Issue : April - June Volume : 2012 Issue Number : 2 Articles : 8 Articles
Background: Three extracts were prepared from the leaves of Accacia salicina; ethyl acetate (EA), chloroform (Chl)\r\nand petroleum ether (PE) extracts and was designed to examine antimutagenic, antioxidant potenty and oxidative\r\nDNA damage protecting activity.\r\nMethods: Antioxidant activity of A. salicina extracts was determined by the ability of each extract to protect\r\nagainst plasmid DNA strand scission induced by hydroxyl radicals. An assay for the ability of these extracts to\r\nprevent mutations induced by various oxidants in Salmonella typhimurium TA102 and TA 104 strains was\r\nconducted. In addition, nonenzymatic methods were employed to evaluate anti-oxidative effects of tested extracts.\r\nResults: These extracts from leaf parts of A. salicina showed no mutagenicity either with or without the metabolic\r\nenzyme preparation (S9). The highest protections against methylmethanesulfonate induced mutagenicity were\r\nobserved with all extracts and especially chloroform extract. This extract exhibited the highest inhibitiory level of\r\nthe Ames response induced by the indirect mutagen 2- aminoanthracene. All extracts exhibited the highest ability\r\nto protect plasmid DNA against hydroxyl radicals induced DNA damages. The ethyl acetate (EA) and chloroform\r\n(Chl) extracts showed with high TEAC values radical of 0.95 and 0.81 mM respectively, against the ABTS.+.\r\nConclusion: The present study revealed the antimutagenic and antioxidant potenty of plant extract from Accacia\r\nsalicina leaves....
Background: Training of infectious disease (ID) specialists is structured on classical clinical microbiology training in\r\nTurkey and ID specialists work as clinical microbiologists at the same time. Hence, this study aimed to determine\r\nthe clinical skills and knowledge required by clinical microbiologists.\r\nMethods: A cross-sectional study was carried out between June 1, 2010 and September 15, 2010 in 32 ID\r\ndepartments in Turkey. Only patients hospitalized and followed up in the ID departments between January-June\r\n2010 who required consultation with other disciplines were included.\r\nResults: A total of 605 patients undergoing 1343 consultations were included, with pulmonology, neurology,\r\ncardiology, gastroenterology, nephrology, dermatology, haematology, and endocrinology being the most frequent\r\nconsultation specialties. The consultation patterns were quite similar and were not affected by either the nature of\r\ninfections or the critical clinical status of ID patients.\r\nConclusions: The results of our study show that certain internal medicine subdisciplines such as pulmonology,\r\nneurology and dermatology appear to be the principal clinical requisites in the training of ID specialists, rather\r\nthan internal medicine as a whole....
For centuries, plants have been used in traditional medicines and there has been recent interest in the\r\nchemopreventive properties of compounds derived from plants. In the present study, we investigated the\r\nantibutyrylcholinestrasic (anti-BuChE) and antioxidant (against some free radicals) activities of extracts from Rhus\r\npentaphyllum. Aqueous extracts were prepared from powdered R. pentaphyllum roots, leaves and seeds and\r\ncharacterized for the presence of tannins, flavonoids and coumarins. Seeds aqueous extract contained the highest\r\nquantities of both flavonoids and tannins (21.12% and 17.45% respectively). In the same way, seeds extracts\r\ndisplayed remarkable inhibition against BuChE over 95%, at 100 �µg/ml and with IC50 0.74 �µg/ml. In addition,\r\ncompared to leaves and roots extracts, seeds aqueous extract revealed relatively strong antiradical activity towards\r\nthe ABTS. (IC50 = 0.25 �µg/ml) and DPPH (IC50 = 2.71 �µg/ml) free radicals and decreased significantly the reactive\r\noxygen species such O2\r\n.- (IC50 = 2.9 �µg/ml) formation evaluated by the non-enzymatic generating O2\r\n.- system\r\n(Nitroblue tetrazolium/riboflavine). These data suggest that the anti-BuChE activities mechanism of these extracts\r\noccurs through a free radical scavenging capacities.\r\nThe present study indicates that extracts of Rhus pentaphyllum leaves, seeds and roots are a significant source of\r\ncompounds, such as tannins, flavonoids and coumarins, with anti-BuChE and antioxidant activities, and thus may\r\nbe useful for chemoprevention....
Background: Treatment of Escherichia coli O157:H7 infections with antimicrobial agents is controversial due to an\r\nassociation with potentially fatal sequelae. The production of Shiga toxins is believed to be central to the\r\npathogenesis of this organism. Therefore, decreasing the expression of these toxins prior to bacterial eradication\r\nmay provide a safer course of therapy.\r\nMethods: The utility of decreasing Shiga toxin gene expression in E. coli O157:H7 with rifampicin prior to bacterial\r\neradication with gentamicin was evaluated in vitro using real-time reverse-transcription polymerase chain reaction.\r\nToxin release from treated bacterial cells was assayed for with reverse passive latex agglutination. The effect of this\r\ntreatment on the survival of E. coli O157:H7-infected BALB/c mice was also monitored.\r\nResults: Transcription of Shiga toxin-encoding genes was considerably decreased as an effect of treating E. coli O157:\r\nH7 in vitro with the minimum inhibitory concentration (MIC) of rifampicin followed by the minimum bactericidal\r\nconcentration (MBC) of gentamicin (> 99% decrease) compared to treatment with gentamicin alone (50-75% decrease).\r\nThe release of Shiga toxins from E. coli O157:H7 incubated with the MIC of rifampicin followed by addition of the MBC\r\nof gentamicin was decreased as well. On the other hand, the highest survival rate in BALB/c mice infected with E. coli\r\nO157:H7 was observed in those treated with the in vivo MIC equivalent dose of rifampicin followed by the in vivo MBC\r\nequivalent dose of gentamicin compared to mice treated with gentamicin or rifampicin alone.\r\nConclusions: The use of non-lethal expression-inhibitory doses of antimicrobial agents prior to bactericidal ones in\r\ntreating E. coli O157:H7 infection is effective and may be potentially useful in human infections with this agent in\r\naddition to other Shiga toxin producing E. coli strains....
A causative agent of human malaria, Plasmodium falciparum, is transmitted by Anopheles mosquitoes. The malaria parasite is\nunder intensive attack from the mosquito�s innate immune system during its sporogonic development. We have used\ngenetic engineering to create immune-enhanced Anopheles stephensi mosquitoes through blood meal-inducible expression\nof a transgene encoding the IMD pathway-controlled NF-kB Rel2 transcription factor in the midgut and fat-body tissue.\nTransgenic mosquitoes showed greater resistance to Plasmodium and microbial infection as a result of timely concerted\ntissue-specific immune attacks involving multiple effectors. The relatively weak impact of this genetic modification on\nmosquito fitness under laboratory conditions encourages further investigation of this approach for malaria control....
Background: This study determined macrolide resistance genotypes in clinical isolates of Streptococcus\r\npneumoniae from multiple medical centers in Lebanon and assessed the serotype distribution in relation to these\r\nmechanism(s) of resistance and the source of isolate recovery.\r\nMethods: Forty four macrolide resistant and 21 macrolide susceptible S. pneumoniae clinical isolates were tested\r\nfor antimicrobial susceptibility according to CLSI guidelines (2008) and underwent molecular characterization.\r\nSerotyping of these isolates was performed by Multiplex PCR-based serotype deduction using CDC protocols. PCR\r\namplification of macrolide resistant erm (encoding methylase) and mef (encoding macrolide efflux pump protein)\r\ngenes was carried out.\r\nResults: Among 44 isolates resistant to erythromycin, 35 were resistant to penicillin and 18 to ceftriaxone.\r\nExamination of 44 macrolide resistant isolates by PCR showed that 16 isolates harbored the erm(B) gene, 8 isolates\r\nharbored the mef gene, and 14 isolates harbored both the erm(B) and mef genes. There was no amplification by\r\nPCR of the erm(B) or mef genes in 6 isolates. Seven different capsular serotypes 2, 9V/9A,12F, 14,19A, 19F, and 23,\r\nwere detected by multiplex PCR serotype deduction in 35 of 44 macrolide resistant isolates, with 19F being the\r\nmost prevalent serotype. With the exception of serotype 2, all serotypes were invasive. Isolates belonging to the\r\ninvasive serotypes 14 and 19F harbored both erm(B) and mef genes. Nine of the 44 macrolide resistant isolates\r\nwere non-serotypable by our protocols.\r\nConclusion: Macrolide resistance in S. pneumoniae in Lebanon is mainly through target site modification but is also\r\nmediated through efflux pumps, with serotype 19F having dual resistance and being the most prevalent and invasive....
The number of pathogens that are required to infect a host, termed infective dose, varies dramatically across pathogen\nspecies. It has recently been predicted that infective dose will depend upon the mode of action of the molecules that\npathogens use to facilitate their infection. Specifically, pathogens which use locally acting molecules will require a lower\ninfective dose than pathogens that use distantly acting molecules. Furthermore, it has also been predicted that\npathogens with distantly acting immune modulators may be more virulent because they have a large number of cells in\nthe inoculums, which will cause more harm to host cells. We formally test these predictions for the first time using data\non 43 different human pathogens from a range of taxonomic groups with diverse life-histories. We found that pathogens\nusing local action do have lower infective doses, but are not less virulent than those using distant action. Instead, we\nfound that virulence was negatively correlated with infective dose, and higher in pathogens infecting wounded skin,\ncompared with those ingested or inhaled. More generally, our results show that broad-scale comparative analyses can\nexplain variation in parasite traits such as infective dose and virulence, whilst highlighting the importance of mechanistic\ndetails....
Tuberculosis (TB) and HIV co-infections place\r\nan immense burden on health care systems and pose\r\nparticular diagnostic and therapeutic challenges. Infection\r\nwith HIV is the most powerful known risk factor\r\npredisposing for Mycobacterium tuberculosis infection\r\nand progression to active disease, which increases the\r\nrisk of latent TB reactivation 20-fold. TB is also the most\r\ncommon cause of AIDS-related death. Thus, M. tuberculosis\r\nand HIV act in synergy, accelerating the decline of\r\nimmunological functions and leading to subsequent\r\ndeath if untreated. The mechanisms behind the breakdown\r\nof the immune defense of the co-infected individual\r\nare not well known. The aim of this review is to highlight\r\nimmunological events that may accelerate the development\r\nof one of the two diseases in the presence of the coinfecting\r\norganism. We also review possible animal\r\nmodels for studies of the interaction of the two\r\npathogens, and describe gaps in knowledge and needs\r\nfor future studies to develop preventive measures against\r\nthe two diseases....
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