Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology, inert calcium carbonate (CaCO3) particles, whose diameter is consistent with the size of pores or apertures in the reservoir, were selected as the bridging agent, and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drilling, NLTDFS was used to conduct dynamic and static damage experiments of cores for 48 hours, respectively, and then the experimented cores were permeated with pure nitrogen from the undamaged end to the damaged one to measure their recovery of permeability. The results showed that the permeability recovery rate of the core reached 90% or so, and the damaged depth was less than 1 cm, which demonstrates that NL TDFS has higher temporary bridging effectiveness and lower damage to the gas-reservoir than other drilling fluids system. NLTDFS has been used to drill many horizontal wells, and four of them have obtained high yield of natural gas. The yield of natural gas of LPl well reached 85 X 104 m3/day after completion with the rump pipe. The formation of the stable well wall and smooth drilling led to an API loss less than 4 mL and an HTHP loss less than 15 mL.

Aim To explore the effects and mecha-nisms of choro-oxime derivatives on spatial learning and memory impairment in Kunming mice and SD rats induced by scopolamine and Aβ1-42 , respectively. Methods 40 Kunming mice were randomly divided into 5 groups: control group, model group, donepezil treatment group, arimoclomol treatment group and TCO-2 treatment group. There were 8 mice in each group. Mice of control group were established by intra-peritoneal injection of saline, and mice of other groups were injected with scopolamine and caused memory im-pairment. Both control group and model group were treated with solvent by intraperitoneal administration;donepezil treatment group received donepezil by intra-gastric administration; arimoclomol treatment group and TCO-2 treatment group were given the correspond-ing drugs by abdominal injection, respectively. The solvent and drugs were given at the same time every morning for 8 days. Spatial learning and memory abili-ty were tested by Morris water maze from the fifth day of the drugs administration. 40 SD rats were divided into 5 groups the same as the dementia model men-tioned above. Mice of control group were established by intracerebroventricular injection of saline, and mice of other groups were injected with insoluble Aβ1-42 to be induced of memory impairment. Solvent and drugs were also delivered as mentioned above. Morris water maze was carried out from the fifth day of the drug de-livery. After that, acetyl cholinesterase activity of hip-pocampus was tested with acetyl cholinesterase reagent kit; the content of Aβ1-42 in hippocampus was meas-ured by ELISA assay kit;the expression of phosphoryl-ated tau proteins was detected by Western Blot. Re-sults In both two dementia models, choro-oxime de-rivatives could improve the spatial learning and memory ability, shorten the escape latency and increase the times of crossing the former platform. Choro-oxime de-rivatives could also inhibit the acetyl cholinesterase ac-tivity in animal brain, decrease the concentration of Aβ1-42 and the expression of phosphorylated tau pro-teins in the dementia rats’ hippocampus. Conclusions Spatial learning and memory deficits induced by sco-polamine and Aβ1-42 could be reversed by choro-oxime derivatives. It may be concerned with enhancement of the cholinergic system functions and reduction of the levels of Aβ1-42 and phosphorylated tau proteins in the brain.

Memantine is a non-competitive N-methyl-D-aspartate receptor (NMDAR) antagonist clinically approved for moderate-to-severe Alzheimer's disease (AD) to improve cognitive functions. There is no report about the proteomic alterations induced by memantine in AD mouse model yet. In this study, we investigated the protein profiles in the hippocampus and the cerebral cortex of AD-related transgenic mouse model (3×Tg-AD) treated with memantine. Mice (8-month) were treated with memantine (5 mg/kg/bid) for 4 months followed by behavioral and molecular evaluation. Using step-down passive avoidance (SDA) test, novel object recognition (NOR) test and Morris water maze (MWM) test, it was observed that memantine significantly improved learning and memory retention in 3xTg-AD mice. By using quantitative proteomic analysis, 3301 and 3140 proteins in the hippocampus and the cerebral cortex respectively were identified to be associated with AD abnormalities. In the hippocampus, memantine significantly altered the expression levels of 233 proteins, among which PCNT, ATAXIN2, TNIK, and NOL3 were up-regulated, and FLNA, MARK 2 and BRAF were down-regulated. In the cerebral cortex, memantine significantly altered the expression levels of 342 proteins, among which PCNT, PMPCB, CRK, and MBP were up-regulated, and DNM2, BRAF, TAGLN 2 and FRY1 were down-regulated. Further analysis with bioinformatics showed that memantine modulated biological pathways associated with cytoskeleton and ErbB signaling in the hippocampus, and modulated biological pathways associated with axon guidance, ribosome, cytoskeleton, calcium and MAPK signaling in the cerebral cortex. Our data indicate that memantine induces higher levels of proteomic alterations in the cerebral cortex than in the hippocampus, suggesting memantine affects various brain regions in different manners. Our study provides a novel view on the complexity of protein responses induced by memantine in the brain of AD.
Alzheimer Disease ; Animals ; Axons ; Brain ; Calcium ; Cerebral Cortex ; Cognition ; Computational Biology ; Cytoskeleton ; Hippocampus ; Learning ; Memantine ; Memory ; Mice ; Mice, Transgenic ; N-Methylaspartate ; Proteome ; Ribosomes ; Water

BACKGROUND:As a member of bone morphogenetic proteins,growth differentiation factor-5 shows promising potential in the application of cartilage and bone repair.The affinity of growth differentiation factor-5 onto bone tissue determines protein use efficiency,so it is of great significance to prepare growth differentiation factor-5 with bone targeting capability. OBJECTIVE:To modify growth differentiation factor-5 using bisphosphonates and investigate the effects of modified protein on the growth of preosteoblasts in mice. METHODS:Pamidronate disodium/growth differentiation factor-5 complex was prepared using chemical crosslinking to couple growth differentiation factor-5 with pamidronate disodium.The functional groups and structures of the complex were characterized using Fourier transform infrared spectroscopy and circular dichromatography.To determine the bone targeting in vitro,the binding of the modified growth differentiation factor-5 with calcium phosphate and in vitro release amount of growth differentiation factor-5 were measured with an ELISA kit.Growth differentiation factor-5(control group)and the pamidronate disodium/growth differentiation factor-5 complex(experimental group)were co-cultured with preosteoblasts MC3T3-E1.Individually cultured cells were blank controls.The effect of the complex on cell proliferation and differentiation was evaluated. RESULTS AND CONCLUSION:(1)The infrared spectroscopy and circular dichromatography results indicated that the bisphosphonate/growth differentiation factor-5 complex was successfully prepared without significant changes in the protein secondary structure.In vitro protein adsorption results showed that growth differentiation factor-5 adsorption on calcium phosphate was increased by about one time after coupling with a bisphosphonate.In the presence of cysteine,growth differentiation factor-5 could be released from the bisphosphonate/growth differentiation factor-5 complex.(2)CCK-8 assay results showed that the absorbance value of the experimental group cultured for 4 and 7 days was higher than that of the control group and blank control group(P<0.000 1).After 7 days of culture,the expression of alkaline phosphatase in the experimental group was significantly higher than that in the control group and blank control group(P<0.000 1).After 13 days of culture,the content of calcium nodules in the experimental group was significantly higher than that in the control group and the blank control group(P<0.000 1).The results of qRT-PCR showed that the mRNA expression of alkaline phosphatase,osteocalcin and Runx2 in the experimental group was higher than that in the control group and the blank control group after 7 days of culture(P<0.01,P<0.001,P<0.000 1).(3)These findings exhibit that bisphosphonate modification can enhance the binding capacity of growth differentiation factor-5 to calcium phosphate as well as improve its biological activity.