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Very Potent (very + potent)
Selected AbstractsIsolation and characterization of naphthalene-degrading bacteria from sediments of Cadiz area (SW Spain)ENVIRONMENTAL TOXICOLOGY, Issue 5 2008D. Nair Abstract Petroleum hydrocarbon contamination of harbor sediments from shipping activity, fuel oil spills, and runoffs are becoming a great concern because of the toxicity and recalcitrance of many of the fuel components. Polycyclic aromatic hydrocarbons (PAHs) are of most concern due to their toxicity, low volatility, resistance to degradation, and high affinity for sediments. Microorganisms, especially bacteria, play an important role in the biodegradation of these hydrocarbons. The objective of the present study was to characterize and isolate PAH-(naphthalene) degrading bacteria in the coastal sediments of Cadiz (SW Spain), since this area is mostly polluted by PAH occurrence. A total of 16 naphthalene-utilizing bacteria were isolated from these sites. Introduction of bacteria isolated from contaminated sediments into mineral medium contributed to the increased rate of hydrocarbon utilization. The bacterial isolates obtained from these sites are very potent in utilizing naphthalene and crude oil. It would be interesting to assess if the selected naphthalene-degrading isolates may degrade other compounds of similar structure. Hence these isolates could be very helpful in bioremediating the PAH-contaminated sites. Further pursue on this work might represent eco-friendly solution for oil contamination on sea surface and coastal area. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Differential sensitivity of sodium channels from the central and peripheral nervous system to the scorpion toxins Lqh-2 and Lqh-3EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2002Haijun Chen Abstract The scorpion ,-toxins Lqh-2 and Lqh-3, isolated from the venom of the Israeli yellow scorpion Leiurus quinquestriatus hebraeus, were previously shown to be very potent in removing fast inactivation of rat skeletal muscle sodium channels (Chen et al., 2000). Here, we show that tetrodotoxin-sensitive neuronal channels NaV1.2 and NaV1.7, which are mainly expressed in mammalian central and peripheral nervous systems, respectively, are differentially sensitive to these two toxins. rNaV1.2 and hNaV1.7 channels were studied with patch-clamp methods upon expression in mammalian cells. While Lqh-3 was about 100-times more potent in removing inactivation in hNaV1.7 channels compared with rNaV1.2, Lqh-2 was about 20-times more active in the other direction. Site-directed mutagenesis showed that the differences in the putative binding sites for these toxins, the S3-4 linkers of domain 4, are of major importance for Lqh-3, but not for Lqh-2. [source] Review article: success and failure of nucleoside and nucleotide analogues in chronic hepatitis BALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2007W. F. LEEMANS SUMMARY Background, Strong suppression of viral replication and normalization of alanine aminotransferase is feasible with nucleos(t)ide analogues. It is estimated viral replication and liver inflammation can be controlled in 90% of patients with chronic hepatitis B with the current available treatments. Aim, To review the studies currently available on the management of chronic hepatitis B with nucleos(t)ide analogues. Results, Although very potent, nucleos(t)ide analogues are not effective in every patient. Some factors are known to influence treatment outcome, but many host and viral factors are still unknown. Stopping rules have to be defined to assess treatment efficacy in an early stage and change the regimen. Discontinuation of nucleos(t)ide analogues is often followed by reactivation of HBV. Data on the risk factors for relapse are necessary in order to decide if treatment can be safely discontinued. Another major drawback of nucleos(t)ide analogues is the emergence of resistance. The efficacy of compounds for the treatment of mutant virus and the impact of cross-resistance is largely unknown. The use of combination therapy to prevent resistance looks promising, but has to be proven. Conclusions, HBV has become a treatable disease, however much research is needed to optimize treatment for individual patients and treatment failures. [source] Antibacterial and Hemolytic Activities of Quaternary Pyridinium Functionalized PolynorbornenesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 5 2008Tarik Eren Abstract In this study, amphiphilic polyoxanorbornene with different quaternary alkyl pyridinium side chains were synthesized. The biological efficiencies of these polymers, with various alkyl substituents, were determined by bacterial growth inhibition assays and hemolytic activity (HC50) against human red blood cells (RBCs) to provide selectivity of these polymers for bacterial over mammalian cells. A series of polymers with different alkyl substituents (ethyl, butyl, hexyl, octyl, decyl and phenylethyl) and two different molecular weights (3 and 10 kDa) were prepared. The impact of alkyl chain length divided the biological activity into two different cases: those with an alkyl substituent containing four or fewer carbons had a minimum inhibitory concentration (MIC) of 200 µg,·,mL,1 and a HC50 greater than 1,650 µg,·,mL,1, while those with six or more carbons had lower MICs,,,12.5 µg,·,mL,1 and HC50,,,250 µg,·,mL,1. Using MSI-78, the potent Magainin derivative which has an MIC,=,12.0 µg,·,mL,1 and HC50,=,120 µg,·,mL,1, as a comparison, the polymers with alkyl substituents ,C4 (four carbons) were not very potent, but did show selectivity values greater than or equal to MSI-78. In contrast, those with alkyl substituents ,C6 were as potent, or more potent, than MSI-78 and in three specific cases demonstrated selectivity values similar to, or better than, MSI-78. To understand if these polymers were membrane active, polymer induced lipid membrane disruption activities were evaluated by dye leakage experiments. Lipid composition and polymer hydrophobicity were found to be important factors for dye release. [source] Sulfamates and their therapeutic potentialMEDICINAL RESEARCH REVIEWS, Issue 2 2005Jean-Yves Winum Abstract Starting from the very simple molecule sulfamic acid, O -substituted-, N -substituted-, or di-/tri-substituted sulfamates may be obtained, which show specific biological activities which were or started to be exploited for the design of many types of therapeutic agents. Among them, sulfamate inhibitors of aminoacyl-tRNA synthetases (aaRSs) were recently reported, constituting completely new classes of antibiotics, useful in the fight of drug-resistant infections. Anti-viral agents incorporating sulfamate moieties have also been obtained, with at least two types of such derivatives investigated: the nucleoside/nucleotide human immunodeficiency virus (HIV) reverse transcriptase inhibitors, and the HIV protease inhibitors (PIs). In the increasing armamentarium of anti-cancer drugs, the sulfamates occupy a special position, with at least two important targets evidenced so far: the steroid sulfatases (STSs) and the carbonic anhydrases (CAs). An impressing number of inhibitors of STSs of the sulfamate type have been reported in the last years, with several compounds, such as 667COUMATE among others, progressing to clinical trials for the treatment of hormone-dependent tumors (breast and prostate cancers). This field is rapidly evolving, with many types of new inhibitors being constantly reported and designed in such a way as to increase their anti-tumor properties, and decrease undesired features (for example, estrogenicity, a problem encountered with the first generation such inhibitors, such as EMATE). Among the many isozymes of CAs, at least two, CA IX and CA XII, are highly overexpressed in tumors, being generally absent in the normal tissues. Inhibition of tumor-associated CAs was hypothesized to lead to novel therapeutic approaches for the treatment of cancer. Many sulfamates act as very potent (low nanomolar) CA inhibitors. The X-ray crystal structure of the best-studied isozyme, CA II, with three sulfamates (sulfamic acid, topiramate, and EMATE) has recently been reported, which allowed for a rationale drug design of new inhibitors. Indeed, low nanomolar CA IX inhibitors of the sulfamate type have been reported, although such compounds also act as efficient inhibitors of isozymes CA I and II, which are not associated with tumors. A large number of anti-convulsant sulfamates have been described, with one such compound, topiramate, being widely used clinically as anti-epileptic drug. By taking into consideration a side effect of topiramate, an anti-epileptic drug leading to weight loss in some patients, it has recently been proposed to use this drug and related sulfamates for the treatment of obesity. The rationale of this use is based on the inhibition of the mitochondrial CA isozyme, CA V, involved in lipogenesis. Some sulfamates were also shown to possess potent inhibitory activity against acyl coenzyme A:cholesterol acyltransferase, an enzyme involved in cholesterol metabolism. One such agent, avasimibe, is in advanced clinical trials for the treatment of hyperlipidemia and atherosclerosis. Thus, the sulfamate moiety offers very attractive possibilities for the drug design of various pharmacological agents, which are on one hand due to the relative ease with which such compounds are synthesized, and on the other one, due to the fact that biological activity of most of them is impressive. © 2004 Wiley Periodicals, Inc. [source] Synthesis and Biological Activity of Endomorphin-2 Analogs Incorporating Piperidine-2-, 3- or 4-Carboxylic Acids Instead of Proline in Position 2CHEMICAL BIOLOGY & DRUG DESIGN, Issue 1 2008Renata Staniszewska Novel endomorphin-2 (EM-2) analogs have been synthesized, incorporating unnatural amino acids with six-membered heterocyclic rings, such as piperidine-2-, 3- and 4-carboxylic acids (Pip, Nip and Inp, respectively) instead of Pro in position 2. [(R)-Nip2]EM-2 displayed an extremely high affinity for the ,-opioid receptor with IC50 = 0.04 ± 0.01 nm in comparison with IC50 = 0.69 ± 0.03 nm for EM-2. This analog was also very potent in the aequorin luminescence-based functional calcium assay and showed significantly enhanced stability in rat brain homogenate. [source] Parental knowledge of topical therapies in the treatment of childhood atopic dermatitisCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 5 2003P. E. Beattie Summary Poor adherence with therapy is a major cause of treatment failure in atopic dermatitis. Reasons given are multifactorial, and include fear of real or imaginary side-effects, under-prescribing, failure to renew prescriptions on time, lack of time, and child refusal of therapy. Most important, however, is lack of knowledge about treatment, in particular the use of topical corticosteroid (TCS) therapy. We conducted a questionnaire-based study to determine the level of use and knowledge of commonly prescribed TCS preparations amongst parents or carers of 100 children attending paediatric outpatient clinics. Weakly potent TCSs were the most commonly used (86%), but poorly understood. Only 35 (41%) who had used hydrocortisone were aware that it was weakly potent, and 44% graded it as moderately potent. Of 65 who had used the moderately potent TCS clobetasone butyrate 0.05% (Eumovate®; Glaxo Wellcome, Uxbridge, UK), 19 (29%) graded it as potent and eight (12%) as weak. Of 50 who had used betamethasone valerate 0.1% (Betnovate®; Glaxo Wellcome, Uxbridge, UK), 42% did not grade it as potent. Understanding of TCS/antimicrobial combinations was generally worse. The hydrocortisone 1%/fusidic acid 2% combination (Fucidin H®; Leo, Risborough, Bucks, UK) was graded as moderate or strong by 88% of the 74 who had used it. Over half (53%) of the 34 using the combination of clobetasone butyrate 0.05%/nystatin 100 000 i.u./g tetracycline 3% (Trimovate®; Glaxo Wellcome, Uxbridge, UK) assumed that it was a potent TCS. Forty-nine had used Fucibet® (betamethasone valerate 0.1%, fusidic acid 2%; Leo, Risborough, Bucks, UK) but 34.5% did not grade it as potent. There was poor knowledge of the strengths of some of the most commonly used TCSs, and all steroid/antimicrobial combinations were perceived as being of greater potency than the constituent steroid alone. Fusidic acid was thought to be a steroid by almost half (46.9%) of the respondents. The packaging of the different products by some pharmaceutical companies is remarkably similar and labelling contains information on the compound and percentage rather than potency of the TCS. This may be a source of confusion. We recommend that manufacturers clearly label TCS products by potency as mild, moderate, potent or very potent and that packaging is sufficiently different for each strength of TCS or emollient to avoid confusion. In order to achieve optimal topical treatment for atopic dermatitis, patients and their carers must receive adequate information and training in how and when to use topical therapies in conjunction with written care plans. [source] | |||||||||||||