Search results for "xanthine"
showing 10 items of 139 documents
Influence of Age on Cerebral Housekeeping Gene Expression for Normalization of Quantitative Polymerase Chain Reaction after Acute Brain Injury in Mice
2015
To prevent methodological errors of quantitative PCR (qPCR) normalization with reference genes is obligatory. Although known to influence gene expression, impact of age on housekeeping gene expression has not been determined after acute brain lesions such as traumatic brain injury (TBI). Therefore, expression of eight common control genes was investigated at 15 min, 24 h, and 72 h after experimental TBI in 2- and 21-month-old C57Bl6 mice. Expression of β2-microglobulin (B2M), β-actin (ActB), and porphobilinogen deaminase (PBGD) increased after TBI in both ages. β2M demonstrated age-dependent differences and highest inter- and intragroup variations. Expression of cyclophilin A, glyceraldehyd…
Blood T-cell Vβ transcriptome in melanoma patients
2004
Tumor-cells have been shown to elicit MHC-restricted and antigen-specific T-cell responses. In this article, we used a new approach to study T-cell responses in tumor-bearing patients based on a global representation of the Vβ-transcriptome, making it possible to grade CDR3-length distribution (CDR3-LD) alterations. Six patients with advanced melanoma disease, from whom blood samples were taken before and serially after tyrosinase-A peptide vaccination, were studied. The PBMC from patients displayed highly significant Vβ transcriptome alterations as compared to healthy individuals. Similar Vβ alterations could be detected both in PBMCs and at the tumor site. After vaccination, Vβ alteration…
P5
2013
Background Pathogenic action of nitric oxide (NO) is responsible to a large extent for development of complications of the diabetes mellitus (DM). NO overproduction is largerly responsible for development of diabetic nephropathy. Thus search for compounds modifying NO production appears to be important for development of pharmacological remedies for treatment of DM complications. Dihydropiridines (DHP) appear to be prospective compounds from this point of view. The goal of the present work was to study alterations of NO production in streptozotocin model of DM in rats and ability of several DHPs and to normalize NO synthesis in kidneys of these animals. Methods Diabetes mellitus was induced…
Multiple signal transduction pathways regulate clusterin (gp 80) gene expression in MDCK cells
1996
ABSTRACT Clusterin (gp 80, apolipoprotein J, TRPM-2) is a widely expressed multifunctional glycoprotein. Its demonstrated and proposed functions include the transport of lipids and membrane fragments, the inhibition of the cytolytic action of the terminal complement complex and the modulation of cell—cell interactions. The expression of the gene is enhanced during tissue injury and remodelling and by hormone-withdrawal-induced apoptosis of prostate and mammary cells. We show here that, in the kidney-derived epithelial cell line MDCK, clusterin mRNA is repressed by glucocorticoids and by progesterone. Treatment with epidermal growth factor also represses clusterin gene expression in MDCK cel…
Estradiol decreases xanthine dehydrogenase enzyme activity and protein expression innon-tumorigenicand malignant human mammary epithelial cells
2009
The retinoic acid deficiency in breast tumour epithelial cells has been ascribed to an insufficient expression of either the enzyme(s) involved in its biosynthesis or the cellular retinol binding protein (CRBP) or both. In an attempt to define the mechanisms underpinning retinoic acid deficiency in these cell model systems, we have investigated the potential regulatory effect of oestrogen (17β-estradiol) on one key player in retinoic acid biosynthesis, the xanthine dehydrogenase (XDH). This enzyme is consistently expressed and very active in non-malignant human mammary epithelial cells (HMEC), as opposed to tumour MDA-MB231 and MCF7 cells. In these latter two cell lines, as opposed to HMEC …
Determination of theophylline and paraxanthine in urine samples by liquid chromatography using the H-point standard additions method
1992
Abstract The simultaneous determination of theophylline and paraxanthine in urine samples by the H-point standard additions method (HPSAM) is described. Samples are extracted with C 18 solid-phase extraction cartridges and chromatographed using a Hypersil C 18 -ODS column and a mobile phase consisting of acetonirile-phosphate buffer in the gradient elution mode. Under these conditions theophylline and paraxanthine are eluted with short retention times. Although their chromatographic peaks are overlapped and their spectra are very similar, the H-point standard additions method provides excellent results in the determination of both xanthines at therapeutic levels.
Effects of the Phosphodiesterase Inhibitor Enoximone on the Autonomic Innervation of the Isolated Heart
1989
Enoximone is a selective inhibitor of a low Km, cyclic AMP-specific type of phosphodiesterase (PDE III). In guinea pig and chicken atria, enoximone (0.1-100 mumol/L) caused a weak increase in the force of contraction. The heart rate was slightly enhanced or was unchanged (chicken). Enoximone (30 mumol/L) also failed to shift the concentration-response curves for the positive inotropic and chronotropic effects of norepinephrine in guinea pig atria. Under almost the same conditions, enoximone and the nonselective PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX) markedly potentiated the forskolin-induced mobilization of choline from phospholipids. The concentrations of IBMX (100 mumol/L) and o…
Biotransformation of caffeine and theophylline in mammalian cell lines genetically engineered for expression of single cytochrome P450 isoforms
1992
Primary steps in the metabolism of caffeine and theophylline are cleavage of methyl groups and/or hydroxylation at position 8, mediated by cytochromes P450. V79 Chinese hamster cells genetically engineered for stable expression of single forms of rat cytochromes P450IA1, P450IA2 and P450IIBI and human P450IA2 and rat liver epithelial cells expressing murine P450IA2 were used to overcome problems arising in the proper allocation of metabolic pathways to specific isoforms by conventional techniques. These cell lines were exposed to caffeine and/or theophylline, and concentrations of metabolites formed in the medium were determined by HPLC. Caffeine was metabolized by human, rat and murine P45…
In vitro antioxidant properties, DNA damage protective activity, and xanthine oxidase inhibitory effect of cajaninstilbene acid, a stilbene compound …
2010
The antioxidant properties, DNA damage protective activities, and xanthine oxidase (XOD) inhibitory effect of cajaninstilbene acid (CSA) derived from pigeon pea leaves were studied in the present work. Compared with resveratrol, CSA showed stronger antioxidant properties, DNA damage protective activity, and XOD inhibition activity. The IC(50) values of CSA for superoxide radical scavenging, hydroxyl radical scavenging, nitric oxide scavenging, reducing power, lipid peroxidation, and XOD inhibition were 19.03, 6.36, 39.65, 20.41, 20.58, and 3.62 μM, respectively. CSA possessed good protective activity from oxidative DNA damage. Furthermore, molecular docking indicated that CSA was more poten…
A comparative investigation of DNA adducts, DNA strand breaks and gene mutations induced by benzo[a]pyrene and (+/-)-anti-benzo[a]pyrene-7,8-diol 9,1…
1997
Abstract Genotoxic effects of benzo[ a ]pyrene (BP) and its reactive metabolites (±)- anti -benzo[ a ]pyrene-7,8-diol 9,10-oxide ((±)- anti -BPDE) were comparatively investigated in vitro with the permanent human fibroblast cell line MRC5CV1. Induced DNA adducts were measured by 32 P-postlabeling, DNA strand breakage was determined by the comet assay and the HPRT gene mutation test was used to detect cytotoxicity and mutagenicity. Treatment of MRC5CV1 cells with S9 mix-activated BP or with (±)- anti -BPDE resulted in a concentration-dependent increase in DNA adducts and strand breaks. Genotoxic effects of BP and (±)- anti- BPDE were detected by 32 P-postlabeling and the comet assay with sim…