Search results for "Tetracyclines"
showing 10 items of 11 documents
Modulation of Nitric Oxide Production by Tetracyclines and Chemically Modified Tetracyclines
1999
Chemically modified tetracyclines (CMTs) dose-dependently decreased inducible nitric oxide synthase (iNOS) and, consequently, nitric oxide (NO) formation by the lipopolysaccharide (LPS)-stimulated J774 line. The inhibitory effect was due to a specific reduction in the iNOS protein content in the cells, as attested by Western blot analysis and by the inhibition of iNOS mRNA accumulation. Furthermore, CMTs cause a dose-dependent increase in cell death in the J774 line mediated by the NO-independent apoptotic mechanism.
Trastuzumab therapy vs tetracycline controlled ERBB2 downregulation: influence on tumour development in an ERBB2-dependent mouse tumour model
2008
Trastuzumab (Herceptin) has improved therapy of breast cancer. Only patients overexpressing ERBB2 are treated with trastuzumab, whereas its use in tumours without ERBB2 expression is useless. This led to the concept that the subgroup of trastuzumab-sensitive tumours is ‘ERBB2-dependent', meaning that ERBB2 signalling is indispensable for growth of these tumours. We used a mouse model that allows anhydrotetracycline (ATc)-controlled downregulation of ERBB2 in tumour tissue. ERBB2 mRNA and protein expression were downregulated below detection limit leading to a macroscopically complete tumour remission within 14 days. Tumour remission was accompanied by a strong decrease in proliferation, a m…
Both cholestatic and steatotic drugs trigger extensive alterations in the mRNA level of biliary transporters in rat hepatocytes: Application to devel…
2016
Disruption of the vectorial bile acid transport in the liver is a key feature of cholestatic drugs, although many causal and mechanistic aspects are still unknown. The aim of the present study was to explore if cholestatic drugs can repress or induce the expression of hepatic transporters. To this end, sandwich-cultured rat hepatocytes were treated with cholestatic and non-cholestatic (steatotic, non-hepatotoxic, etc.) drugs and the mRNA expression of 10 uptake and efflux biliary transporters was measured. Results evidenced that all cholestatic drugs cause extensive alterations in the mRNA expression of most biliary transporters. Surprisingly, nearly all steatotic drugs also affected the ex…
Perspectives for the Treatment of Brucellosis in the 21st Century: The Ioannina Recommendations
2007
Policy Forum. Competing interests: ER has received research grants from Daiichi, Bayer, and Theravance and has served as a consultant to Pfizer, Theravance, Bayer, Wyeth, Rosetta, and BiondVax. Summary Points Brucellosis remains the commonest anthropozoonosis worldwide, and its treatment remains complex, requiring protracted administration of more than one antibiotic. In November 2006, a consensus meeting aimed at reaching a common specialist statement on the treatment of brucellosis was held in Ioannina, Greece under the auspices of the International Society of Chemotherapy and the Institute of Continuing Medical Education of Ioannina. The author panel suggests that the optimal treatment o…
4-Epidoxycycline: an alternative to doxycycline to control gene expression in conditional mouse models
2004
Since the pioneering work by Gossen and Bujard in 1992 demonstrating the usefulness of the Escherichia coli derived tet resistance operon for regulating gene expression a large collection of doxycycline-controlled transgenic mice has been established. Gene switching in eukaryotic tissue culture cells or mice requires administration of tetracycline, anhydrotetracycline or doxycycline to efficiently inactivate the transactivator protein tTA (TET-OFF system) or alternatively to activate the reverse transactivator protein rtTA (TET-ON system). However, the antibiotic activity of doxycycline can create an imbalance of the intestinal flora, resulting in diarrhoea and in a smaller number of animal…
Anti-inflammatory effects of chemically modified tetracyclines by the inhibition of nitric oxide and interleukin-12 synthesis in J774 cell line
2001
We investigated the effects of chemically modified tetracyclines (CMTs) on the production of nitric oxide (NO) and on the synthesis of some cytokines: tumour necrosis factor alpha (TNF-alpha), interleukin(IL)-10 and IL-12 in lipopolysaccharide (LPS)-treated J774 cell line. Furthermore, we studied the ability of these drugs to modify the viability in LPS-stimulated J774 macrophages. CMTs decreased, in a dose-dependent manner, inducible NO synthase (iNOS) activity and, consequently, nitrite formation in J774 cultures. The CMT-induced decrease in NO production is due to the inhibition of enzyme activity rather than to a direct effect on enzyme expression. The absence of the inhibition in mRNA …
In vitro activities of tetracyclines against different clones of multidrug-resistant Acinetobacter baumannii isolates from two Iranian hospitals.
2014
Acinetobacter baumannii has emerged as one of the most challenging healthcare-related pathogens and its occurrence has increased worldwide, especially in patients admitted to intensive care units. A. baumannii isolates are frequently resistant to multiple antimicrobial agents and there are recent reports of isolates resistant to virtually all clinically relevant drugs. In the present study, the in vitro activities of tigecycline, minocycline and doxycycline against 67 MDR-AB isolates recovered from 29 burn and 38 non-burn Iranian patients hospitalised in Tehran and Tabriz, respectively, were studied. Tigecycline and minocycline may be still considered effective therapeutic options for MDR-A…
[Macrolides in the treatment of children with Mediterranean spotted fever].
2002
Till now there is not a gold standard therapy for Mediterranean spotted fever (MSF) in children. Standard treatment for MSF is the administration of tetracycline or chloramphenicol, however both these drugs can cause significant adverse effects in children (tetracyclines can cause staining of teeth, chloramphenicol severe hematological adverse events such as aplastic anemia, gray baby syndrome and hemolytic anemia in patients with the Mediterranean form of G6PD deficiency). We conducted two randomized clinical trials; the first compared clarithromycin versus chloramphenicol: mean time to defervescence was 36.7 +/- 18.1 h in the clarithromycin group and 47.1+/- 21.9 h in the chloramphenicol …
Chemically modified tetracyclines induce cytotoxic effects against J774 tumour cell line by activating the apoptotic pathway
2003
Here, we have studied the effects of chemically modified tetracyclines (CMTs) on apoptosis both at the level of the cytoplasmic proteolytic caspase cascade, and on Bcl-2 and c-myc mRNA expression in the J774 macrophage cell line. The results indicate that CMTs induce morphological changes consistent with apoptotic events, as clearly demonstrated both by the acridine orange and ethidium bromide staining, and by TUNEL and fragmentation ELISA assays. Furthermore, the analysis of the cell cycle by flow cytometry shows an evident apoptotic sub-G0G1 peak, without important modifications in the cell cycle distribution. CMTs induce programmed cell death (PCD) in a dose-dependent manner and CMT-8 is…
Photo-induced fluorescence of magnesium derivatives of tetracycline antibiotics in wastewater samples
2009
Abstract An analytical strategy, for the determination of tetracyclines (TCs), based on a HPLC system coupled with a photo-reactor followed by post-column derivatization was developed. Higher fluorescence emission after coupling the resulting photo-fragments with magnesium ions was observed for the determination of minocycline (MC), epitetracycline (ETC), tetracycline (TC) and doxycycline (DC). The manifold included a HPLC system with a photo-reactor (PTFE tubing helically coiled around a low-pressure mercury lamp), a mixing T-piece and a fluorescence detector. The derivatization reagent was delivered at 0.5 mL min −1 by a pump. After HPLC separation using a gradient system with a mobile ph…