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Sample records for 1,3-dimethylxanthine

  1. Magnetic resonance studies of irradiated 1,3-dimethylxanthine

    ESR and ENDOR techniques were used to study the x-ray induced damage in single crystals of the organic molecule theophylline (1,3 dimethylxanthine). A K-band spectrometer operating at 25GHz was used for ESR and ENDOR measurements. X-irradiation was carried out at 25K, 80K, and at room temperature, and spectra were observed as the temperature was varied. The low temperature experiments were achieved by using a closed cycle helium refrigeration system. A detailed analysis was made of the spectra, and four different radicals (R1, R2, R3, and R4) were identified after irradiation. Radical R1 was identified as a hydrogen atom radical, stable from 20 to 6OK; radical R2 was identified as an anion radical stable from 20 to 8OK; radical R3 was formed by hydrogen abstraction from the methyl group at C(10); and radical R4 was found to be a hydrogen-adduct species. Radical R3 was characterized by the following parameters: (1) Methylene hydrogen hyperfine tensor values of 28.8, 17.8, 13.2 G, and 27.7, 18.9, 8.8 G; (2) g-tensor values of 2.0012, 2.0019, and 2.0036; (3) Isotropic methyl group coupling of 4 G; (4) A spin density of 0.68 on C(10). Radical R4 was characterized by (1) an isotropic methelene hydrogen coupling of 37.1 G; (2) a maximum nitrogen coupling at N(9) of 21 G; (3) hydrogen coupling tensor values, due to protonation at N(g), of 12.0, 8.5, and 3.0 G; (4) rotating methyl group tensor values, at N(l), of 2.38, 2.71, and 5.19 MHz; (5) g-tensor values of 2.0012, 2.0033, and 2.0049; (6) spin density of 0.38 on N(9). A kinetics study indicated that radical R3 converts to radical R4 at about 160 K

  2. Magnetic resonance studies of irradiated 1,3-dimethylxanthine

    Majid, E.

    1989-01-01

    ESR and ENDOR techniques were used to study the x-ray induced damage in single crystals of the organic molecule theophylline (1,3 dimethylxanthine). A K-band spectrometer operating at 25GHz was used for ESR and ENDOR measurements. X-irradiation was carried out at 25K, 80K, and at room temperature, and spectra were observed as the temperature was varied. The low temperature experiments were achieved by using a closed cycle helium refrigeration system. A detailed analysis was made of the spectra, and four different radicals (R1, R2, R3, and R4) were identified after irradiation. Radical R1 was identified as a hydrogen atom radical, stable from 20 to 6OK; radical R2 was identified as an anion radical stable from 20 to 8OK; radical R3 was formed by hydrogen abstraction from the methyl group at C(10); and radical R4 was found to be a hydrogen-adduct species. Radical R3 was characterized by the following parameters: (1) Methylene hydrogen hyperfine tensor values of 28.8, 17.8, 13.2 G, and 27.7, 18.9, 8.8 G; (2) g-tensor values of 2.0012, 2.0019, and 2.0036; (3) Isotropic methyl group coupling of 4 G; (4) A spin density of 0.68 on C(10). Radical R4 was characterized by (1) an isotropic methelene hydrogen coupling of 37.1 G; (2) a maximum nitrogen coupling at N(9) of 21 G; (3) hydrogen coupling tensor values, due to protonation at N(g), of 12.0, 8.5, and 3.0 G; (4) rotating methyl group tensor values, at N(l), of 2.38, 2.71, and 5.19 MHz; (5) g-tensor values of 2.0012, 2.0033, and 2.0049; (6) spin density of 0.38 on N(9). A kinetics study indicated that radical R3 converts to radical R4 at about 160 K.

  3. Bepaling van theofylline (1,3-dimethylxanthine) in hondeplasma met behulp van reversed-phase vloeistofchromatografie

    Olling; M; Besamusca; P.; Rauws; A.G.

    1985-01-01

    In dit rapport wordt een snelle en nauwkeurige methode beschreven voor de bepaling van theofylline in plasma. Theofylline wordt uit plasma geextraheerd met chloroform/2-propanol en met behulp van reversed-phase hogedruk vloeistofchromatografie gescheiden en met spectrofotometrische detectie bepa

  4. A novel transverse push-pull microprobe: in vitro characterization and in vivo demonstration of the enzymatic production of adenosine in the spinal cord dorsal horn.

    Patterson, S L; Sluka, K A; Arnold, M A

    2001-01-01

    Adenosine produces analgesia in the spinal cord and can be formed extracellularly through enzymatic conversion of adenine nucleotides. A transverse push-pull microprobe was developed and characterized to sample extracellular adenosine concentrations of the dorsal horn of the rat spinal cord. Samples collected via this sampling technique reveal that AMP is converted to adenosine in the dorsal horn. This conversion is decreased by the ecto-5'-nucleotidase inhibitor, alpha,beta-methylene ADP. Related behavioral studies demonstrate that AMP administered directly to the spinal cord can reverse the secondary mechanical hyperalgesia characteristic of the intradermal capsaicin model of inflammatory pain. The specific adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT) inhibits the antihyperalgesia produced by AMP. This research introduces a novel microprobe that can be used as an adjunct sampling technique to microdialysis and push-pull cannulas. Furthermore, we conclude that AMP is converted to adenosine in the dorsal horn of the spinal cord by ecto-5'-nucleotidase and subsequently may be one source of adenosine, acting through adenosine A(1) receptors in the dorsal horn of the spinal cord, which produce antihyperalgesia. PMID:11145997

  5. Investigation of Xanthine Drug and some of its Dimethyl Isomers using Mass Spectrometry and Semi-Empirical Molecular Orbital Calculation

    In this paper xanthine (C5H4N4O2 , MW=152) drug (M1) as a parent molecule and three of its dimethyl substituted isomers , namely, 3,7-dimethylxanthine (M2) 1,3-dimethylxanthine (M3) and 1,7-dimethylxanthine (M4) of formula (C7H8N4O2, MW = 180), were investigated using electron ionization (EI) mass spectrometry (MS) at 70 eV. Semi-empirical MO-calculations , PM3 procedure, have been carried out on the drugs as neutral molecule and its corresponding molecular ion. These include molecular geometry (bond length), bond order, charge distribution on different atoms , heat of formation (Hf) and ionization energy. The mass spectral fragmentation pathways of the parent molecule (M1) and the isomeric molecules (M2-M4) were proposed. All compounds dissociate in the gas phase by common pathways, initiated in the same site of bond rupture resulting a loss of imide group. Subsequently, a loss of CO followed by HCN, and formation of different fragmen ions depends on the isomeric position of the methyl groups . The PM3 procedure provides information of initial bond cleavage and subsequent fragmentation of the molecules. Finally, the influence of CH3 groups in different isomeric position via the two rings of xanthine caused by significant electron-donating of this group were discussed

  6. THEOPHYLLINE-INDUCED ALTERATION IN SERUM ELECTROLYTES AND URIC ACID OF ASTHMATIC CHILDREN

    R. Amin

    2003-03-01

    Full Text Available Theophylline, (1,3-dimethylxanthine is widely used as a smooth muscle relaxant, myocardial stimulant and a diuretic agent. The most frequent use of theophylline is in treatment of acute and chronic asthma as a bronchodilator.To determine the effect of Theophylline on serum electrolyte and uric acid, 21 asthmatic children (age range 1,5-7 years with severe acute asthma and 25 patients with chronic asthma (5-15 years who were being treated with slow-release theophylline were enrolled in this study. Fifty age and sex matched normal children took part as control. Blood samples (5ml were withdrawn before, during and after completion of the course of intravenous theophylline treatment (0.05-0.70 mg/kg/ hr. Sera obtained were used for analysis of K+, Na+, phosphorus, calcium and uric acid by RA-1000 automated analyzer and the following results were obtained:(1 After treatment, total serum calcium in acute asthmatic patients decreased significantly compared with controls (PWe conclude that the serum levels of phosphate, potassium, calcium and uric acid should be monitored in patient receiving theophylline especially during prolonged use and critical emergency cases.

  7. Local structure analysis of some Cu(II) theophylline complexes

    David, L.; Cozar, O.; Forizs, E.; Cr ăciun, C.; Ristoiu, D.; B ălan, C.

    1999-10-01

    The CuT 2L 2·2H 2O complexes [T=Theophylline (1,3-dimethylxanthine); L=NH 3, n-propylamine (npa), 2-aminoethanol (ae)] were prepared and investigated by ESR spectroscopy. Powder ESR spectrum of CuT 2(NH 3) 2·2H 2O is axial ( g||=2.255, g⊥=2.059). ESR spectrum of CuT 2(npa) 2·2H 2O with ( g||=2.299, g⊥=2.081) is a superposition of one axial ( g||=2.299, g⊥=2.073) and one isotropic component ( g0≈2.089), in the same amount. The axial spectra of the former complexes are due to a static Jahn-Teller effect ( EJT≈2880 cm -1). ESR spectrum of CuT 2(ae) 2·2H 2O is orthorhombic ( g1c=2.199, g2c=2.095, g3c=2.037). The local symmetries around the Cu(II) ions remain unchanged by DMF solvating, by adsorbing these solutions on NaY zeolite or by lowering the temperature.

  8. Theophylline-Based KMUP-1 Improves Steatohepatitis via MMP-9/IL-10 and Lipolysis via HSL/p-HSL in Obese Mice

    Bin-Nan Wu

    2016-08-01

    Full Text Available KMUP-1 (7-[2-[4-(2-chlorobenzenepiperazinyl]ethyl]-1,3-dimethylxanthine has been reported to cause hepatic fat loss. However, the action mechanisms of KMUP-1 in obesity-induced steatohepatitis remains unclear. This study elucidated the steatohepatitis via matrix metallopeptidase 9 (MMP-9 and tumor necrosis factor α (TNFα, and related lipolysis via hormone sensitive lipase (HSL and adipose triglyceride lipase (ATGL by KMUP-1. KMUP-1 on steatohepatitis-associated HSL/p-HSL/ATGL/MMP-9/TNFα/interleukin-10 (IL-10 and infiltration of M1/M2 macrophages in obese mice were examined. KMUP-1 was administered by oral gavage from weeks 1–14 in high-fat diet (HFD-supplemented C57BL/6J male mice (protection group and from weeks 8–14, for 6 weeks, in HFD-induced obese mice (treatment group. Immunohistochemistry (IHC and hematoxylin and eosin (H&E staining of tissues, oil globules number and size, infiltration and switching of M1/M2 macrophages were measured to determine the effects on livers. IL-10 and MMP-9 proteins were explored to determine the effects of KMUP-1 on M1/M2 macrophage polarization in HFD-induced steatohepatitis. Long-term administration of KMUP-1 reversed HFD-fed mice increased in body weight, sGOT/sGPT, triglyceride (TG and glucose. Additionally, KMUP-1 decreased MMP-9 and reactive oxygen species (ROS, and increased HSL/p-HSL and IL-10 in HFD mice livers. In conclusion, KMUP-1, a phosphodiesterase inhibitor (PDEI, was shown to reduce lipid accumulation in liver tissues, suggesting that it could be able to prevent or treat steatohepatitis induced by HFD.