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PubMed2005

De novo seropositive rheumatoid arthritis during immunosuppressive treatment after kidney transplantation.

We detected de novo seropositive erosive rheumatoid arthritis (RA) in a patient seven years after successful cadaveric kidney transplantation (RTx). RA developed in spite of treatment with cyclosporine A (CyA), methylprednisolon (MP) and azathioprine (Aza), compounds often also used for treatment of active RA. Renal failure was due to diabetes mellitus (DM) nephropathy. Besides a slight increase in C-reactive protein (CRP) concentration two years after RTx, the clinical symptoms of RA were observed seven years after RTx. RA was confirmed by X-ray examination, isotopic skeletal scan and positive serum RA factor. After switching Aza to methotrexate (Mtx) treatment, his symptoms disappeared and CRP concentration returned to normal. Our patient had HLA DRB1 *0101, *0401 alleles and DQB1 *0501, *0302 alleles which have strong genetic association with both DM and RA. To our best knowledge, this is the first case in which de novo seropositive erosive RA developed while on treatment with triple immunosuppression after RTx. The immunosuppressive treatment probably masked the inflammation and symptoms of RA.

Adolescent↗
PubMed2006

Charge migration in dicationic electrophiles and its application to the synthesis of aza-polycyclic aromatic compounds.

[reaction: see text] Superacid-promoted reactions of dicationic electrophiles have been studied, and the positive charge centers are found to migrate apart in a predictable manner. Using isotopic labeling the charge migration is found in one system to occur through successive deprotonation-reprotonation steps. The charge migration chemistry is the basis for new general synthetic route to aza-polycyclic aromatic compounds.

Aza Compounds↗
PubMed2002

Studies on azaspiracid biotoxins. II. Mass spectral behavior and structural elucidation of azaspiracid analogs.

In this report, the mass spectral analysis of azaspiracid biotoxins is described. Specifically, the collision-induced dissociation (CID) behavior and differences between CID spectra obtained on a triple-quadrupole, a quadrupole time-of-flight, and an ion-trap mass spectrometer are addressed here. The CID spectra obtained on the triple-quadrupole mass spectrometer allowed the classification of the major product ions of the five investigated compounds (AZA 1-5) into five distinct fragment ion groups, according to the backbone cleavage positions. Although the identification of unknown azaspiracids was difficult based on CID alone, the spectra provided sufficient structural information to allow confirmation of known azaspiracids in marine samples. Furthermore, we were able to detect two new azaspiracid analogs (AZA 1b and 6) in our samples and provide a preliminary structural analysis. The proposed dissociation pathways under tandem mass spectrometry (MS/MS) conditions were confirmed by a comparison with accurate mass data from electrospray quadrupole time-of-flight MS/MS experiments. Regular sequential MS(n) analysis on an ion-trap mass spectrometer was more restricted in comparison to the triple-quadrupole mass spectrometer, because the azaspiracids underwent multiple [M + H - nH(2)O](+) (n = 1-6) losses from the precursor ion under CID. Thus, the structural information obtained from MS(n) experiments was somewhat limited. To overcome this limitation, we developed a wide-range excitation technique using a 180-u window that provided results comparable to the triple-quadrupole instrument. To demonstrate the potential of the method, we applied it to the analysis of degraded azaspiracids from mussel tissue extracts.

Animals↗
PubMed1992

Studies on geranylgeranyl diphosphate synthase from rat liver: specific inhibition by 3-azageranylgeranyl diphosphate.

Geranylgeranyl diphosphate synthase from rat liver was separated from farnesyl diphosphate synthase, the most abundant and widely occurring prenyltransferase, by DEAE-Toyopearl column chromatography. The enzyme catalyzed the formation of E,E,E-geranylgeranyl diphosphate (V) from isopentenyl diphosphate (II) and dimethylallyl diphosphate (I), geranyl diphosphate (III), or farnesyl diphosphate (IV) with relative velocities of 0.09:0.15:1. 3-Azageranylgeranyl diphosphate (VII), designed as a transition-state analog for the geranylgeranyl diphosphate synthase reaction, was synthesized and found to act as a specific inhibitor for this synthase, but not for farnesyl diphosphate synthase. Diphosphate V and its Z,E,E-isomer (VI) also inhibited geranylgeranyl diphosphate synthase, but the effect was not as striking as that of the aza analog VII. Specific inhibition of geranylgeranyl diphosphate synthase by VII was also observed in experiments with 100,000g supernatants of rat brain and liver homogenates which contained isopentenyl diphosphate isomerase and prenyltransferases including farnesyl diphosphate synthase as well as geranylgeranyl diphosphate synthase. For farnesyl:protein transferase from rat brain, however, the aza compound did not show a stronger inhibitory effect than E,E,E-geranylgeranyl diphosphate.

Animals↗
PubMed2005

Degradation of CL-20 by white-rot fungi.

In previous studies, we found that the emerging energetic chemical, CL-20 (C6H6N12O12, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), can be degraded following its initial denitration using both aerobic and anaerobic bacteria. The C and N mass balances were not determined due to the absence of labeled starting compounds. The present study describes the degradation of the emerging contaminant by Phanerochaete chrysosporium using ring-labeled [15N]-CL-20 and [14C]-CL-20. Ligninolytic cultures degraded CL-20 with the release of nitrous oxide (N2O) in amounts corresponding to 45% of the nitrogen content of CL-20. When ring-labeled [15N]-CL-20 was used, both 14N14NO and 15N14NO were observed, likely produced from -NO2 and N-NO2, respectively. The incubation of uniformly labeled [14C]-CL-20 with fungi led to the production of 14CO2 (> 80%). Another ligninolytic fungus, Irpex lacteus, was also able to degrade CL-20, but as for P. chrysosporium, no early intermediates were observed. When CL-20 was incubated with manganese peroxidase (MnP), we detected an intermediate with a [M-H]- mass ion at 345 Da (or 351 and 349 Da when using ring-labeled and nitro-labeled [15N]-CL-20, respectively) matching a molecular formula of C6H6N10O8. The intermediate was thus tentatively identified as a doubly denitrated CL-20 product. The concomitant release of nitrite ions (NO2-) with CL-20 degradation by MnP also supported the occurrence of an initial denitration prior to cleavage and decomposition.

Aniline Compounds↗
PubMed2005

Metabolism of the aliphatic nitramine 4-nitro-2,4-diazabutanal by Methylobacterium sp. strain JS178.

The aliphatic nitramine 4-nitro-2,4-diazabutanal (NDAB; C2H5N3O3) is a ring cleavage metabolite that accumulates during the aerobic degradation of the energetic compound hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by various Rhodococcus spp. NDAB is also produced during the alkaline hydrolysis of either RDX or octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and during the photolysis of RDX. Traces of NDAB were observed in a soil sampled from an ammunition-manufacturing facility contaminated with both HMX and RDX, suggesting natural attenuation. In this study, we report the isolation of a soil bacterium that is able to degrade NDAB under aerobic conditions. The isolate is a pink-pigmented facultative methylotroph affiliated with the genus Methylobacterium. The strain, named Methylobacterium sp. strain JS178, degrades NDAB as a sole nitrogen source, with concomitant growth and formation of 1 molar equivalent of nitrous oxide (N2O). Comparison of the growth yield of strain JS178 grown on NDAB, nitrite (NO2-), or ammonium (NH4+) as a nitrogen source revealed that 1 N equivalent is assimilated from each mole of NDAB, which completes the nitrogen mass balance. In radiotracer experiments, strain JS178 mineralized 1 C of the [14C]NDAB produced in situ from [14C]RDX by Rhodococcus sp. strain DN22. Studies on the regulation of NDAB degradation indicated that allantoin, an intermediate in the purine catabolic pathway and a central molecule in the storage and transport of nitrogen in plants, up-regulated the enzyme(s) involved in the degradation of the nitramine. The results reveal the potential for the sequential participation of rhodococci and methylobacteria to effect the complete degradation of RDX.

Aerobiosis↗
PubMed2001

Micellar electrokinetic chromatography of tri aza aromatic ligand compounds of iron (II): influence of bile salt type on enantiomeric separation.

Micellar electrokinetic chromatography is used with a variety of bile salt micelles to separate the enantiomers of bis(8-((pyridine-2-methylene)amino)quinoline)iron(II) hexafluorophosphate, Fe(PMAQ)2(PF6)2; bis(8-((pyridine-2-methylene)amino)lepidine iron(II) hexafluorophosphate, Fe(PMAL)2(PF6)2; and bis(1-(2-pyridinyl)ethylidine)-8-aminoquinoline iron(II) hexafluorophosphate, Fe(PEAQ)2(PF6)2. The influence of ten different bile salts on the resolution of each pair of enantiomers is investigated. Significant changes in resolution are seen depending upon the bile salt used. The dihydroxy bile salts are superior to the trihydroxy bile salts in terms of resolution, and the taurine or glycine conjugated bile salts yield better results than the unconjugated bile salts. Resolution for most enantiomers is maximized in a buffer solution containing 10-15% acetone and employing either taurochenodeoxycholic or glycochenodeoxycholic acid as the bile salt. Evidence for the separation of the corresponding Fe(III) complexes is presented.

Aza Compounds↗
PubMed2000

Synthesis and antiproliferative activity of some variously substituted acridine and azacridine derivatives.

A group of 9-substituted acridine and azacridine derivatives (m-AMSA analogues) were synthesised following classical procedures as potential antitumour agents with inhibitory effects on DNA topoisomerase II. Some were found to have noticeable cytotoxicity against human HL-60 and HeLa cells grown in culture. Their non-covalent interactions with calf thymus DNA have been studied using fluorescence quenching. We evaluated DNA damage produced by the tested compounds by means of DNA filter elution and protein precipitation techniques. Catalytic studies carried out with purified topoisomerase confirmed these agents as antitopoisomerase inhibitors. Chemotherapy of solid-tumour-bearing mice with tested compounds allowed an aza-analogue (compound IIIb), as potent as m-AMSA but less toxic towards the host, to be recognised.

Acridines↗
PubMed1995

Correlation of DNA reactivity and cytotoxicity of a new class of anticancer agents: aza-anthracenediones.

Doxorubicin and mitoxantrone are carboxyclic anti-cancer drugs that interact with DNA through intercalation. Our laboratory has synthesized a new series of anti-tumor agents, the aza-anthracenediones, which are structurally related to mitoxantrone but contain a heterocyclic, rather than a carbocyclic, chromophore. Both the in vivo and in vitro anti-tumor activities of these compounds were exquisitely sensitive to the positioning of the nitrogen atom within the heterocyclic backbone. Compounds having a 2-aza were 30- to 100-fold more potent than the 1-aza or the di-aza compounds against L1210 cells in vitro. When tested in vivo, the 2-aza-anthracenediones had marked anti-tumor activity, in some cases curative, whereas the 1-aza-anthracenediones had but minimal antitumor activity. To define the importance of the aza positioning on DNA reactivity, spectral shift and gel mobility assays were used. The spectral shift assay suggested that the 2-aza compounds reacted with DNA solely through intercalation whereas the 1-aza-anthracenediones, and mitoxantrone all reacted with DNA through intercalative and non-intercalative processes. The affinity of DNA binding was five to seven times greater for the 2-aza compounds compared to the 1-aza or the di-aza derivatives. The retardation of supercoiled pBR322 DNA mobility in agarose gel electrophoresis further suggested an intercalative type of DNA interaction. Differences in DNA interaction appear related to but can not completely account for differences in cytotoxicity of the aza anthracenediones.

Animals↗
PubMed2005

Toxicity of emerging energetic soil contaminant CL-20 to potworm Enchytraeus crypticus in freshly amended or weathered and aged treatments.

We investigated the toxicity of an emerging polynitramine energetic material hexanitrohexaazaisowurtzitane (CL-20) to the soil invertebrate species Enchytraeus crypticus by adapting then using the Enchytraeid Reproduction Test (ISO/16387:2003). Studies were designed to develop ecotoxicological benchmark values for ecological risk assessment of the potential impacts of accidental release of this compound into the environment. Tests were conducted in Sassafras Sandy Loam soil, which supports relatively high bioavailability of CL-20. Weathering and aging procedures for CL-20 amended into test soil were incorporated into the study design to produce toxicity data that better reflect soil exposure conditions in the field compared with the toxicity in freshly amended soils. Concentration-response relationships for measurement endpoints were determined using nonlinear regressions. Definitive tests showed that toxicities for E. crypticus adult survival and juvenile production were significantly increased in weathered and aged soil treatments compared with toxicity in freshly amended soil, based on 95% confidence intervals. The median effect concentration (EC50) and EC20 values for juvenile production were 0.3 and 0.1 mg kg-1, respectively, for CL-20 freshly amended into soil, and 0.1 and 0.035 mg kg-1, respectively, for weathered and aged CL-20 soil treatments. These findings of increased toxicity to E. crypticus in weathered and aged CL-20 soil treatments compared with exposures in freshly amended soils show that future investigations should include a weathering and aging component to generate toxicity data that provide more complete information on ecotoxicological effects of emerging energetic contaminants in soil.

Aniline Compounds↗
PubMed1999

Synthesis of a protected 3,4-dihydroxyproline from a pentose sugar.

[reaction: see text] D-Ribonolactone (6) was transformed into N-((fluorenylmethoxy)carbonyl)-3,4-bis-O-(tert-butyldimethylsilyl)-D-2,3-cis-3,4-cis-3,4-dihydroxyproline (13) in nine chemical steps. This represents a potentially general strategy for the synthesis of 3,4-dihydroxyprolines, utilizing the pentose sugar series as starting materials.

Aluminum Compounds↗
PubMed1977

Dissociation of lipolysis from the levels of cyclic AMP in rat epididymal fat cells.

Two compounds, theophylline and 8-aza-9-furfuryl-adenine (SQ 4665), were found to maximally stimulate lipolysis in preparations of rat epididymal fat cells in the absence of exogenous hormones. Cyclic AMP levels in lipocytes maximally stimulated by either agent alone were unchanged from control levels. In contrast, lipolysis stimulated by either epinephrine alone or in combination with several cyclic nucleotide phosphodiesterase inhibitors correlated well with increases in the levels of cyclic AMP observed. These results suggest the presence of a non-cyclic AMP dependent pathway for the stimulation of lipolysis in rat epididymal fat cells.

Adenine↗
PubMed2005

Efficient solid-phase synthesis of highly functionalized 1,4-benzodiazepin-5-one derivatives and related compounds by intramolecular aza-Wittig reactions.

Due to their widespread biological activities and favorable pharmacokinetic properties, benzodiazepines were among the first classes of small molecules to be synthesized on solid supports. Since then, there have been numerous reports on the synthesis of similar skeletons. We have employed the T1 triazene linker to yield 1,4-benzodiazepin-5-one. Starting from various substituted triazene resins, cleavage in the presence of an azide donor, such as trimethylsilylazide, gave rise to aryl azides. Intramolecular aza-Wittig reactions produced the appropriately functionalized N-heterocycles. By using this route, the natural product deoxyvasicinone and related compounds were prepared.

Anti-Anxiety Agents↗
PubMedDate not supplied

Synthesis, physicochemical and anticonvulsant properties of N-benzyl and N-aminophenyl derivatives of 2-azaspiro[4.4]nonane and [4.5]decane-1,3-dione. Part I.

To continue our systematic SAR studies, two series of N-benzyl- (X=CH2) and N-aminophenyl- (X=NH) derivatives of 2-azaspiro[4.4]nonane (1a-1j) and 2-azaspiro[4.5]decane-1,3-dione (2a-2j) were synthesized, and evaluated in maximum electroshock seizure (MES), subcutaneous pentylenetetrazole (sc.MET) and rotorod (TOX) tests for their anticonvulsant activity. Among those derivatives, the most potent N-aminophenyl-2-azaspiro[4.4]nonane-1,3-dione 1j had ED50=76.27 mg kg-1. X-ray structures for two pairs of derivatives with a different linker were solved. Then 3-D data for the active 1j versus less active 2j, both having an imine linker (X=NH), and the respective parent of compounds with a methylene linker (X=CH2) (1a and 2a) were discussed.

Alkanes↗
PubMed2006

Expanding the synthetic method and structural diversity potential for the intramolecular Aza Diels-Alder cyclization.

New experimental facets have been examined to expand upon the known methods for an aromatic variant of the intramolecular Aza Diels-Alder cyclization. The specific transformation under study is one that uses functionalized anilines and an aldehyde-olefin tether to provide tetrahydroquinoline cycloadducts under mild acidic conditions. Variations investigated encompass the use of N-alkylated anilines, including one with ring-constrained nitrogen, in the context of glycine, phenylalanine, and glyoxyl ester bridging elements; bridge components with structural perturbations; modified dienophile segments; and different acid catalysts. Substituted tetrahydroquinolines obtained from many of the preceding experiments were obtained in good chemical yield, generally in excess of 80%. Designed as a platform for combinatorial chemical synthesis, this reaction manifold accommodates a range of starting materials with structurally and electronically distinct characteristics. The results of this report, in combination with the discoveries from previous work in this area, enhance the ability of the intramolecular Aza Diels-Alder transformation to generate a diverse array of quinolinic structures with multiple stereogenic centers, many of which resemble lignan and arylnaphthalene-type natural products.

Aldehydes↗