Evaluation of 2-iminoimidazolidin-4-one and thymine as respective internal standards for normal-phase and reversed-phase high-performance liquid chromatographic determination of creatinine in human serum

Pharmacokinetic Profile and Acute Toxicological Properties of a Novel Radiosensitizer Cytosine-Phosphate-Guanosine Oligodeoxynucleotide 107 in Mice Following Intravenous and Orthotopic Administration

The synthetic cytosine-phosphate-guanosine oligodeoxynucleotide 107 (CpG ODN107) is a novel radiosensitizer for glioma treatment. However, the information related to its pharmacokinetics and toxicity remains unclear. Therefore, the plasma pharmacokinetics, distribution, elimination, and acute toxicity of CpG ODN107 in mice were investigated in the present experiments. The results from the liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay showed that the plasma elimination half-life (t1/2β) of CpG ODN107 in BALB/c mice varied slightly with the dose, and it was 0.65, 0.49, and 0.50 h at the intravenous doses of 2.5, 5, and 10 mg/kg, respectively. CpG ODN107 rapidly and widely distributed in organs/tissues, except the brain and testes. The highest concentrations were found in the liver (28.6% of the administered dose after 0.5 h) and the kidneys (5.7% of the administered dose after 1 h). CpG ODN107 (0.3, 3, and 30 μg/mL) could highly bind to human and mouse plasma proteins in vitro. CpG ODN107 in the forms of prototype was excreted in urine (1.79%) and feces (0.91%), and its shortened metabolites were excreted in urine (2.1%) and feces (2.2%) within the first 24 h. The mice in vivo optical image showed CpG ODN107 labeled with Alexa Fluor 680 fluorochrome (AF680) accumulated in the brain after orthotopic injection, eliminated very slowly, and excreted in urine compared with poly T labeled with AF680. The median lethal dose (LD50) of CpG ODN107 was 75.7 mg/kg for mice; this dose only could produce apparent spleen and liver damage, in line with the distribution features of CpG ODN. In conclusion, our present pharmacokinetic and toxicity investigation will provide helpful information to further pharmacodynamic and pharmacokinetic research of CpG ODN107 and other oligodeoxynucleotide drugs in the future.

Imprinted polymer-modified hanging mercury drop electrode for differential pulse cathodic stripping voltammetric analysis of creatine

The molecularly imprinted polymer [poly(p-aminobenzoicacid-co-1,2-dichloroethane)] film casting was made on the surface of a hanging mercury drop electrode by drop-coating method for the selective and sensitive evaluation of creatine in water, blood serum and pharmaceutical samples. The molecular recognition of creatine by the imprinted polymer was found to be specific via non-covalent (electrostatic) imprinting. The creatine binding could easily be detected by differential pulse, cathodic stripping voltammetric signal at optimised operational conditions: accumulation potential -0.01 V (versus Ag/AgCl), polymer deposition time 15s, template accumulation time 60s, pH 7.1 (supporting electrolyte< or =5 x 10(-4)M NaOH), scan rate 10 mV s(-1), pulse amplitude 25 mV. The modified sensor in the present study was found to be highly reproducible and selective with detection limit 0.11 ng mL(-1) of creatine. Cross-reactivity studies revealed no response to the addition of urea, creatinine and phenylalanine; however, some insignificant magnitude of current was observed for tryptophan and histidine in the test samples.

Changes in ear-pinna temperature as a useful measure of stress in sheep (Ovis aries)

Activation of the sympathetic nervous system, with associated increases in heart rate and the redistribution of blood in preparation for ‘fight or flight’, is an integral part of the ‘defence reaction’. In sheep, the defence reaction involves vasoconstriction in the ear-pinna. If decreases in ear-pinna temperature (Tp) can be used to indicate vasoconstriction, then it may be possible to use changes in Tp as a measure of the defence reaction. Ewe lambs were exposed to stressors including mustering into pens, moving between pens, isolation from conspecifics, and prolonged periods of exercise. Measurements of heart rate (HR), Tp, vaginal temperature (Tv), and salivary cortisol and urinary catecholamine concentrations were used to assess stress responses. A repeatable pattern of changes in HR, Tp and Tv was observed in response to stressors. Short-term disturbances resulted in increased HR, reduced Tp, and increased Tv. More sustained disturbances — for example, prolonged periods of exercise — resulted in a sustained elevation in HR, a sustained decrease in Tp, and a sustained elevation in Tv. The highest levels of cortisol and catecholamines were associated with the treatments that resulted in the longest periods of decreased Tp. We infer that changes in Tp occur largely in response to changes in sympathetic nervous activity, and that the potential exists to measure elements of stress responses by monitoring Tp in freely behaving animals. This is a minimally invasive measure that allows the monitoring of modest numbers of animals over prolonged periods with minimal handling.