Pharmacokinetics of doxycycline in laying hens after intravenous and oral administration.

The pharmacokinetics of doxycycline in laying hens was investigated after a single intravenous (IV) or an oral (PO) dose at 20 mg/kg body weight. The concentrations of doxycycline in plasma samples were determined by high-performance liquid chromatography with an ultraviolet detector, and pharmacokinetic parameters were calculated using a compartmental model method. The disposition of doxycycline after one single IV injection was best described by a two-compartment open model and the main pharmacokinetic parameters were as follows: volume of distribution (Vd) was 865.15 ± 127.64 ml/kg, distribution rate constant (α) was (2.28 ± 0.38) 1/h, elimination rate constant (ß) was 0.08 ± 0.02 1/h and total body clearance (Cl) was104.11 ± 18.32 ml/h/kg, while after PO administration, the concentration versus time curve was best described by a one-compartment open model and absorption rate constant (Ka), peak concentration (Cmax), time to reach Cmax (tmax) and absolute bioavailability (F) were 2.55 ± 1.40 1/h, 5.88 ± 0.70 µg/ml, 1.73 ± 0.75 h and 52.33%, respectively. The profile of doxycycline exhibited favourable pharmacokinetic characteristics in laying hens, such as quick absorption and slow distribution and elimination, though oral bioavailability was relatively low. A multiple-dosing regimen (a dose of 20 mg/kg/d for 3 consecutive days) of doxycycline was recommended to treat infections in laying hens. But a further study should be conducted to determine the withdrawal time of doxycycline in eggs.

Correlation between chromosome 1p/19q status and VEGF mRNA expression in gliomas.

The chromosome 1p/19q deletion has been reported as a good prognosis marker for gliomas. However, the detection of 1p/19q status alone in glioma patients is not sufficient. The identification of a combination of molecular factors could effectively enhance the prediction accuracy. Thus far, the potential correlation between the 1p/19q status and vascular endothelial growth factor (VEGF) expression has not been elucidated. The level of VEGF mRNA expression in the tumor and the adjacent normal tissues was determined by real-time polymerase chain reaction. The 1p/19q status of glioma patients was determined by fluorescence in situ hybridization. The association between the 1p/19q status and VEGF mRNA expression, as well as the glioma grade, was evaluated. A higher VEGF mRNA expression level was observed in gliomas, compared to matched normal tissues (P < 0.01). The 1p/19q status was significantly correlated with glioma grade (P = 0.018) and VEGF mRNA expression in the tissues (P = 0.005). A higher percentage of patients with high-grade gliomas displayed an intact 1p/19q and higher VEGF mRNA expression than those with low-grade gliomas. A survival analysis revealed that patients (with high- and low-grade gliomas) with intact 1p/19q and higher VEGF mRNA expression showed a shorter overall survival time. Moreover, tissue VEGF mRNA expression and WHO grade were found to be independent risk factors for gliomas. In conclusion, the 1p/19q status and VEGF mRNA expression in tissues could be used in combination to predict the prognosis of gliomas.

Effect of prenatal exposure to LPS combined with pre- and post-natal high-fat diet on hippocampus in rat offspring.

OBJECTIVE: Prenatal exposure to lipopolysaccharide (LPS) or high-fat diet (HFD) results in hippocampal impairment and cognitive deficits in offspring rats. What is not clear is how prenatal exposure to LPS combined with pre- and post-natal HFD would affect the hippocampus in offspring rats. METHODS: 32 pregnant rats were randomly divided into four groups, including control group; LPS group (pregnant rats were injected with LPS 0.4 mg/kg intraperitoneally on the 8th, 10th and 12th day of pregnancy); HFD group (maternal rats had HFD during pregnancy and the lactation period, and their pups also had HFD up to the third month of life); LPS+HFD group (rats were exposed to the identical experimental scheme with LPS group and HFD group). The serum IL-6 and TNF-alpha concentration was measured in three-month-old offspring rats in all groups. Hippocampal morphology and expressions of glial fibrillary acidic protein (GFAP), Tau and synaptophysin (SYP) in offspring rats were measured. RESULTS: Serum IL-6 and TNF-alpha concentration in the HFD group increased significantly compared with the control group, LPS group and LPS+HFD group. Compared with the control group and the LPS+HFD group, cells in the LPS and HFD groups were smaller and arranged in disorder, and cell membrane was not complete, nucleoli and nuclear heterochromatin stained darkly with hematoxylin. GFAP and Tau expression in the hippocampus of the LPS and HFD groups increased significantly compared with the control group and LPS+HFD group. SYP expression in the LPS and HFD groups decreased significantly compared with the control group and HFD group, increased in the LPS+HFD group. CONCLUSION: Prenatal exposure to LPS combined with pre- and post-natal HFD result in a protective effect on the hippocampus in offspring rats, and it might be a benefit from the predictive adaptive response to prenatal inflammation.

Prenatal exposure to lipopolysaccharide results in cognitive deficits in age-increasing offspring rats.

Studies have suggested that maternal infection/inflammation maybe a major risk factor for neurodevelopmental brain damage. In the present study, we evaluated the effects of prenatal exposure to a low level of inflammatory stimulation lipopolysaccharide (LPS) repeatedly on spatial learning and memory performances in rat offspring's lifetime. Sixteen pregnant Sprague-Dawley rats were randomly divided into two groups. The rats in the LPS group were treated i.p. with LPS (0.79 mg/kg) at gestation day 8, 10 and 12; meanwhile the rats in the control group were treated with saline. After delivery, the rat offspring at 3- (young), 10- (adult) and 20-mon-old (aged) were allocated. Spatial learning and memory abilities were tested by Morris water maze. The structure of hippocampal CA1 region was observed by light microscopy. The expression of synaptophysin (SYP) and glial fibrillary acidic protein (GFAP) in hippocampal CA1 region were measured by immunohistochemistry. Results showed that the rat offspring of LPS group needed longer escape latency and path-length in the Morris water maze and presented a significant neuron loss, decreased expression of SYP, increased expression of GFAP in CA1 region in histological studies. All these changes were more significant with the age increasing. These findings support the hypothesis that maternal systemic inflammation may alter the state of astrocytes in rat offspring for a long time, the alteration may affect neurons and synapse development in neural system, increase the neurons' vulnerability to environment especially as the age increasing, at last result in distinct learning and memory impairment.

Purification and characterization of a non-hemorrhagic metalloprotease from Agkistrodon halys brevicaudus venom.

A non-hemorrhagic metalloprotease (protease L4) was purified from the venom of Chinese Mamushi (Agkistrodon halys brevicaudus) by gel filtration and anion-exchange chromatography. Protease L4 has the molecular weight of 22,000 and its optimum pH was 8.5. The protein was stable in the pH range of 5-9 and below 40 degrees C. The proteolytic activity was inhibited by metal-chelating agents and some metal ions. Calcium ion activated the activity dose-dependently, but had only a minor effect on the thermal and pH stability. L4 showed fibrinogenase activity, hydrolyzing only the A alpha chain of fibrinogen. The protease cleaved preferentially at the N-terminal of Leu and His residues of some peptides.