Search results for "Cyclic compound"
showing 10 items of 819 documents
Über den Chemismus von Zustandsänderungen des Aktomyosins
1950
(1) By means of a simple method the conditions were investigated for contraction and relaxation of actomyosin (AM) under the influence of potassium, magnesium, and calcium ions, of adenosintriphosphate (ATP) or muscle-adenylic-acid and phosphocreatin.
Meropenem Permeation through the Outer Membrane of <i>Pseudomonas aeruginosa</i> Can Involve Pathways Other than the OprD Porin Channel
1996
The outer membrane protein (OMP) OprD is the major channel through which carbapenems permeate the outer membrane of Pseudomonas aeruginosa. In this study, we analyzed the OMP profiles of several P. aeruginosa clinical isolates showing diminished susceptibility to imipenem while remaining susceptible to meropenem. All these isolates lacked OprD or showed a reduced expression of this porin. Susceptibility to meropenem was thus independent of the level of OprD expression, indicating that the antimicrobial could be taken up via an alternative route. The level of expression of OprC (70 kD) was also unrelated to meropenem susceptibility. Nevertheless, OMPs OprF and OprE were expressed by all isol…
Advances in Marine Natural Products of the Indole and Annelated Indole Series: Chemical and Biological Aspects
2001
Marine natural products, form a field of scientific endeavour, that has recently grown considerably. The isolation, biological evaluation, chemical properties and synthetic elaborations of products of marine organisms have attracted the attention of organic chemists, medicinal chemists, biologists and pharmacists. In this context a structurally and biologically highly interesting class is represented by the marine natural products containing an indole moiety in a pure substituted form or in an anellated form. The present review summarizes primarily the actual results concerning these products as new pharmacologically attractive lead compounds for drug design. The chemistry, biological evalu…
Posaconazole concentrations in the central nervous system
2008
more susceptible to the killing activity of caspofungin. This study is the first comparing caspofungin killing activity against the closely related species C. parapsilosis, C. orthopsilosis and C. metapsilosis. Killing curves, regardless of the medium used, showed a decreasing order of susceptibility to caspofungin: C. metapsilosis . C. orthopsilosis . C. parapsilosis. Based on high echinocandin MICs for C. parapsilosis sensu stricto, in the case of isolates identified as C. parapsilosis sensu lato low MICs of echinocandins may be regarded as an indicator that an isolate is in fact C. orthopsilosis or C. metapsilosis; in the case of isolates with low echinocandin MICs, DNA-based identificat…
Regio- and stereoselectivity in the metabolism of benzo[c]phenanthrene mediated by genetically engineered V79 Chinese hamster cells expressing rat an…
1998
Regio- and stereoselective metabolism mediated by cytochrome P450 (CYP) and metabolite-dependent cytotoxicity of benzo[c]phenanthrene (B[c]Ph) and its trans-3,4-dihydrodiol, the metabolic precursor of the carcinogenic fjord-region B[c]Ph-3,4-dihydrodiol 1,2-epoxides (B[c]PhDE), were investigated with V79 Chinese hamster cells genetically engineered for three rat and six human CYP isoforms. The order of the capabilities of the CYP isoforms to metabolize B[c]Ph was as follows: h1A1>r1A1>r1A2>h1B1>h1A2>r2B1>>h2E1>h2A6>h3A4. Regardless of the species, all individual CYP isoforms preferentially catalyzed the oxidation of B[c]Ph at the 5,6-position (K-region) except human CYP1A1 and human CYP1A2,…
Efecto de la administración concomitante de indometacina o ibuprofeno en la farmacocinética de amikacina en neonatos prematuros
2006
Objective: To evaluate whether the concomitant administration of ibuprofen or indomethacin plus amikacin may alter the latter drug's pharmacokinetic parameters, and hence amikacin plasma levels. Method: Retrospective cohort study performed by reviewing the medical records of premature children with persistent ductus arteriosus receiving amikacin and ibuprofen, or amikacin and indomethacin. They were divided up into three groups: group 1: treatment with amikacin went before indomethacin or ibuprofen; group 2: simultaneously treated with amikacin and indomethacin; group 3: simultaneously treated with amikacin and ibuprofen. Pharmacokinetic parameters, distribution volume, and amikacin clearan…
2,3,7,8-Tetrachlorodibenzo-p-dioxin-Dependent Release from Contact Inhibition in WB-F344 Cells: Involvement of Cyclin A
2002
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the most potent tumor promoter ever tested in rodents. Although it is known that most of TCDD actions are mediated by binding to the aryl hydrocarbon receptor (AhR), the mechanisms leading to tumor promotion still remain to be elucidated. Loss of contact inhibition is one characteristic hallmark in tumorigenesis. In rat liver epithelial WB-F344 cells, TCDD induces a release from contact inhibition, which is manifested by a twofold increase in cell number when TCDD (1 nM for 48 h) is added to confluent cells in the presence of serum, but not when given to exponentially growing or subconfluent, serum-deprived WB-F344 cells. Loss of G1 arrest was a…
Über die Beeinflussung der Ca-Aufnahme in Lipidextrakte aus Mikrosomen und Mitochondrien des Herzens durch Digitoxin
1970
Lipids were isolated by chloroform-methanol extraction from mitochondrial and microsomal fractions of guinea-pig hearts. In the presence of digitoxin (10−9-10−6 g/ml) 15–30% more radioactive Ca was taken up by the lipid extracts than under control conditions, but the total amount of Ca in this phase remained unchanged. Thus, digitoxin produced an increase in the specific activity of the lipid-bound Ca which may be explained by an increased exchangeability of this Ca fraction. This effect of digitoxin might result in an improved availability of the lipid-bound Ca for Ca-dependent functions (e.g. contraction) of the heart muscle cell.
Optimization of anti-proliferative activity using a screening approach with a series of bis-heterocyclic G-quadruplex ligands
2013
Abstract Using a phenotypic screening and SAR optimization approach, a phenyl-bis-oxazole derivative has been identified with anti-proliferative activity, optimized with the use of a panel of cancer cell lines. The lead compound was synthesized by means of a short and effective two-step synthesis using Pd-catalyzed direct arylation. The compound stabilizes several quadruplex DNA sequences including a human telomeric DNA and one from the promoter of the HSP90 gene, although the structure–activity relationships of the series are not obviously related to the quadruplex binding.
NODAPA-OH and NODAPA-(NCS)n: Synthesis, 68Ga-radiolabelling and in vitro characterisation of novel versatile bifunctional chelators for molecular ima…
2008
This report concerns synthesis, (68)Ga-radiolabelling and stability data of 1,4,7-triazacyclononane-1,4-diacetic acid-7-p-isothio-cyanatophenyl-acetic acid (NODAPA-NCS), 1,4,7-triazacyclononane-1-acetic acid-4,7-di-p-isothiocyanatophenyl-acetic acid (NODAPA-(NCS)(2)) and 1,4,7-triazacyclononane-1,4-diacetic acid-7-p-hydroxyphenyl-acetic acid (NODAPA-OH), versatile bifunctional chelators with potential for molecular imaging. Protein binding and exemplified conjugation are also reported.