p-Hydroxybenzoic acid (p-HA) modified polymeric micelles for brain-targeted docetaxel delivery

Chemotherapies for brain diseases have been hampered due to the inability of transport of drug across the blood-brain barrier (BBB). In order to overcome the barrier, p-hydroxybenzoic acid (p-HA), a small molecule of benzamide analogue, was used as a ligand for brain-targeted drug delivery. The p-HA was conjugated to PEG-DSPE to form p-HA-PEG-DSPE. Docetaxel-loaded polymeric micelles were prepared by a thin-film hydration method using methoxy-poly(ethylene glycol)-distearoylphosphatidyl- ethanolamine (mPEG 2000 -DSPE) as a carrier and the p-HA-PEG-DSPE as a brain targeted material. The prepared micelles showed spherical with a mean diameter of (18±3) nm. Encapsulation efficiency and drug loading were (83.49±1.3)%, (7.7±1.2)% for un- modified micelles and (80.65±1.6)%, (7.47±1.8)% for p-HA-modified micelles, respectively. In vitro cellular uptake experiments showed that the p-HA-modified micelles increased BCECs cellular uptake by 1.2 times compared to the unmodified micelles. Ex vivo near-infrared fluorescence imaging showed that brain uptake of the p-HA-modified micelles was 1.3-1.8 times higher than that of the unmodified micelles. In vitro cytotoxicity assay against glioblastoma cell U87 MG showed that inhibition rate of the p-HA-modified micelles increased by 1.2 times compared to that of the unmodified micelles and 1.7 times compared to that of DTX. Survival time of nude mice bearing intracranial glioblastoma showed that the lifetime of saline group, Taxotere group, mPEG-DSPE/DTX micelles group and p-HA-PEG-DSPE/DTX micelles group was 22, 27, 32 and 45.8 d, representively, which indicated that anti-glioblastoma activity of DTX could be significantly enhanced by the p-HA-modified polymeric micelles. These results demonstrated that the p-HA-modified micelles could be a promising brain-targeted drug delivery system for hydrophobic drugs against glioblastoma.     

Enhancement of transfection efficiency for HeLa cells via incorporating arsinine moiety into chitosan

Arginine-rich peptides have attracted considerable attention due to their distinct internalization mechanism. It was reported that arginine and guanidino moieties were able to translocate through cell membranes and played a critical role in the process of membrane permeation. In this work, arginine was conjugated to the backbone of chitosan to form a novel chitosan derivative, arginine modified chitosan （Arg-CS）. Arg-CS/DNA complexes were prepared according to the method of coacervation process. The physicochemical properties of Arg-CS and Arg-CS/DNA complexes were characterized and the transfection activity and efficiency mediated by Arg-CS/DNA complexes were investigated taking HeLa cells as target cells. Arg-CS was characterized by FTIR and ^13C NMR. Arg-CS/DNA polyelectrolyte complexes were investigated by agarose gel retardation, dynamic light scattering （DLS） and atomic force microscopy （AFM）. The results revealed that the Arg-CS/DNA complexes started to form at N/P ratio of 2：1, and the size of particles varied from 100 to 180 nm. The cytotoxicity of Arg-CS and their complexes with plasmid DNA were determined by MTT assay for HeLa cells, and the results suggested that Arg-CS/DNA complexes were slightly less toxic than Arg-CS. Moreover, the derivative alone and their complexes showed significantly lower toxicity than PEI and PEI/DNA complexes, respectively. Taking HeLa cells as target cells and using pGL3-control as reporter gene, the luciferase expression mediated by Arg-CS was greatly enhanced to about 100 folds compared with the luciferase expression mediated by chitosan at different pH media. These results suggest that Arg-CS is a promising candidate as a safe and efficient vector for gene delivery and transfection.     

Primary study of a novel Tc-tricarbonyl cocaine analogue as the potential DAT imaging agent

The convenient preparation of organometallic precursor fac-[99mTc(CO)3 (H2O)3] opens a new route to design new radiopharmaceuticals. Based on this precursor, a new cocaine analogue, Tropyn, is designed and synthesized,and “2 1” mixed-ligands approach is used to prepare a neutral complex [^99mTc(CO)3(Tropyn)I]. Biodistribution in mice and rats proves that it has sufficient brain uptake. Rat regional brain biodistribntion indicates that the complex is highly concentrated in the striatum (ST) with rapid clearance in the cortex (CT) and hippocampus (HP), which make it valuable for further investigation as the potential Second-Generation DAT imaging agent.     

Enhancement of transfection efficiency for HeLa cells via incorporating arginine moiety into chitosan

Arginine-rich peptides have attracted considerable attention due to their distinct internalization mechanism. It was reported that arginine and guanidino moieties were able to translocate through cell membranes and played a critical role in the process of membrane permeation. In this work, arginine was conjugated to the backbone of chitosan to form a novel chitosan derivative, arginine modified chitosan (Arg-CS). Arg-CS/DNA complexes were prepared according to the method of coacervation process. The physicochemical properties of Arg-CS and Arg-CS/DNA complexes were characterized and the transfection activity and efficiency mediated by Arg-CS/DNA complexes were investigated taking HeLa cells as target cells. Arg-CS was characterized by FTIR and 13C NMR. Arg-CS/DNA polye- lectrolyte complexes were investigated by agarose gel retardation, dynamic light scattering (DLS) and atomic force microscopy (AFM). The results revealed that the Arg-CS/DNA complexes started to form at N/P ratio of 2:1, and the size of particles varied from 100 to 180 nm. The cytotoxicity of Arg-CS and their complexes with plasmid DNA were determined by MTT assay for HeLa cells, and the results suggested that Arg-CS/DNA complexes were slightly less toxic than Arg-CS. Moreover, the derivative alone and their complexes showed significantly lower toxicity than PEI and PEI/DNA complexes, respectively. Taking HeLa cells as target cells and using pGL3-control as reporter gene, the luciferase expression mediated by Arg-CS was greatly enhanced to about 100 folds compared with the luciferase expression mediated by chitosan at different pH media. These results suggest that Arg-CS is a promising candi- date as a safe and efficient vector for gene delivery and transfection.     

Study on cellular internalization of poly（vinyldiaminotriazine）-based hydrogen bonding type non-viral transgene vector

Previously we successfully prepared poly（vinyldiaminotriazine）（PVDT）-based non-viral vectors which complexed piasmid DNA via hydrogen bonding with adenine-thymine base pairs, in this report, surface charges and complex sizes of this system were further examined. The results showed that PVDT-based polymer could cover surface charges of DNA resulting in slightly negative or neutral complexes. It was also found that the complex sizes were governed by two events： the aggregation induced by the instability of neutral particles, and more compact complexes produced by PVDT-based polymers. In the study of cellular uptake, chlorpromazine and filipin III were used to inhibit clathrin-and caveolae-mediated endocytosis, respectively. We found that PVDT-based systems were transported into cells via a non-clathrin, non-caveolae mediated endocytosis. This special process was studied by temperature inhibition and kinetics assays. It was revealed that such a pathway was characterized by （i） a more en- ergy dependent process and （ii） a much slow transfection-effective internalization.     

Effect of anionic-nonionic mixed surfactant on ryegrass uptake of phenanthrene and pyrene from water

The effect of anionic-nonionic mixed surfactant (SDBS-TX100) on the uptake of phenanthrene and pyrene by ryegrass in a hydroponic system was studied, and the influence factors including the com-positions and concentrations of mixed surfactants and the compounds properties were also discussed. The results showed that SDBS-TX100 mixtures with certain compositions and concentrations could enhance the uptake of phenanthrene and pyrene by ryegrass, which could be attributed to the im-proved uptake capacity of ryegrass roots for phenanthrene and pyrene. SDBS-TX100 can enhance the uptake of phenanthrene and pyrene by ryegrass in a wider range of surfactant concentrations (0―0.8 mmol/L) in comparison with corresponding single surfactants, and the maximal contents of phenan-threne and pyrene in ryegrass roots were obtained with the concentrations of SDBS-TX100 around the corresponding critical micelle concentrations. The uptake of phenanthrene and pyrene by ryegrass increased with the increasing mole fraction of SDBS in mixed surfactant solutions, and SDBS-TX100 mixture with a mole ratio of SDBS to TX100 at 9:1 had the greatest capacity in enhancing the uptake of phenanthrene and pyrene, at which the corresponding maximal concentrations of phenanthrene and pyrene in ryegrass roots were 216 and 8.16 times those without surfactants, respectively. Results from this study indicate that the anionic-nonionic mixed surfactants (SDBS-TX100) would be a preferred selection for the application of surfactant-enhanced phytoremediation technology to contaminated soils.     

Expression of recombinant human lysozyme in the milk of transgenic mice

Human lysozyme is a 130-aa (amino acid) alkaline polypeptide, and has both anti-bacterial and anti-viral properties which make it an important component of human natural immunity system. As a first step toward the ultimate goal of improving the anti-bacterial properties of bovine and ovine milk, a transgenic mouse that contains the genomic DNA sequence of the human lysozme gene has been generated for the first time. From 83 mice generated by microinjection, a total of 6 positive transgenic mice were identified by PCR and Southern blot. F1 mice positive for transgene in lines were also detected by PCR. This shows that transgene could be transmitted from founder transgenic mice to their offspring. Recombinant human lysozyme (rHlys) was found in the whey of 3 female positive transgenic mice by Western blot. The highest concentration of rHlys for transgenic mice was 0.2mg/mL. The antibacterial activity of the whey for transgenic mice was highly enhanced up to 0.4 times as much as that of human, while that of non-transgenic mouse was very low. Although the lysozyme activity of transgenic mice is still lower than that of human, the rHlys exhibits the same specific activity as that of human lysozyme. It provides a strong basis for further studies into the possible application of rHlys express in mammary gland.     

In vivo Dynamic Studies of Brain Metabolism

Nuclear magnetic resonance （NMR） can noninvasively monitor intracellular concentrations and kinetic properties of numerous inorganic and organic compounds. A ^31p NMR surface coil was used in vivo to dynamically measure phosphocreatine （PCr）, adenosine triphosphate （ATP）, and intracellular inorganic phosphate （Pi） levels in mouse brain during ischemia-reperfusion to study the damage of cerebral tissues caused by ischemia and effects of herbs on cerebral energy metabolism during ischemia-reperfusion. The study provides dynamic brain energy metabolism data during different periods. The data show that some herbs more rapidly increase the PCr level during the recovery phase than in the control group.     

Biporous nanocarbon foams and the effect of the structure on the capillary performance

Biporous nanocarbon foams (NC foams) which have both nano-pores and micro-pores,were fabricated and used to explore the liquid transportation in the porous structures formed by nanomaterials.Scanning electron microscopy was utilized to observe the structure of the NC foams.Capillary rise tests using acetone as the working fluid were conducted by the IR thermal imaging method.The results show that the capillary rise height of the NC foam with 65μm micro-pore size was 47%higher than that with 9μm micro-pore size in 50 s.The capillary performance of the NC foams was reduced when its density was higher than 60 mg/cm~3.A model is built to illustrate the effect of both nano-structure and micro-structure on the transportation of working fluid in the biporous foam.The data indicates that the nano-structure generated high capillary pressure while the microstructure provided low resistant pathways for fast liquid transportation.The size of micro-pores and the ratio of micro-pores to nano-pores were two important factors.It is demonstrated that the NC foams had large sorption capacity up to 878 mg/cm~3and their capillary performance was further enhanced when using a substrate.     

Export of particulate organic carbon estimated from234Th-238U disequilibria and its temporal variation in the South China Sea

Activities of²³⁴Th and nutrient concentrations in the upper 500 m water column were measured at a time-series station in the South China Sea over a time span of 12.3 d. Results showed a reduction of dissolved²³⁴Th and an overall increase of particulate²³⁴Th during the period. Meanwhile, activities of total²³⁴Th kept fairly constant, implying rapid transformation of²³⁴Th between the dissolved and particulate forms. Vertical profiles of total²³⁴Th showed evident deficit of²³⁴Th relative to²³⁸U in the upper 500 m water column. Using an irreversible steady-state model of thorium scavenging, export fluxes of particulate organic carbon (POC) corresponding to time pointsT ₁ andT ₂ were estimated to be 46.5 and 13.1 mmolC · m⁻² · d⁻¹. It was demonstrated that the estimation of POC export was greatly dependent on the POC/²³⁴Th_P ratios and the bias caused by the different models of²³⁴Th scavenging, however, was considered to be of minor importance.     

Experimental proof for the regulation ofSalmonella typhimurium purB bypurR

Salmonella typhimurium purB encodes adenylosuccinate lyase (ASL), the enzyme that catalyzes step 8 in the pathway forde novo synthesis of inosine 5′-monophosphate (IMP) and also the final reaction in the two-step sequence from IMP to adenosine monophosphate (AMP). The nucleotide sequence ofpurB was obtained by the genetic map and sequence homologous analysis. The conservedpur operator inpurB was identified to be located 185 bp downstream of the initiation codon and overlaps codons 62 – 67 in the protein-coding region. The binding of PurR to this operator was demonstrated by gel retardation experiment and site-directed mutagenesis, indicating that thepurB is under the control ofpurR. We also answered why previous study had conflicting report concerning the regulation ofpurB bypurR by identifying the junction site ofpurB tolacZ in apurB- MudJ (lacZ,Kan ^r) fusion strain. This result strongly supports that thepurB is the second gene in theycfC-purB operon.     

Establishment ofChlamydomonas reinhardtii chloroplast expression

An expression vector pACⅢ containing the chimeric gene HAV- VP3P1 and HCV-C gene has been constructed and transferred to C. reinhardtii by the biolistic method. The trans-formants have been identified by PCR, Southern-blotting, Northern-blotting and Western-blotting assays after selecting on resistant medium and incubating in the dark. The results show that the chimeric gene has replaced the chIL gene of C. reinhardtii chloroplast genome and expressed correctly under the control of the C. reinhardtii chloroplast double promoters 5' chlL-5' atpA. The analysis of SDS-PAGE indicates that the expressed protein accounts for 5.31 % of total soluble protein.     

Responses of woody plant root and xylem sap ATP to soil drying

The ATP in roots and xylem sap of two woody plant species, Platycladus orientalis and Acacia auriculiformis, subjected to rapid and slow soil drying has been determined employing firefly luciferase ATP assay method (sensitivity is at 10-12 mol ATP L-1). The ATP levels in the two species were 1.6 nmol·gDW-1 and 0.6 nmol·gDW-1 in roots, and 5.6 μmol·m-3 and 8 μmol ·m-3 in xylem sap, respectively. When plants of P. orientalis and A. auriculiformis were subjected to rapid soil drying, respectively, as soil water content (SWC) decreased from the normal level ( 0. 25 g ·gDW-1) to 0. 02 and 0. 06 g ·gDW-1, separately, plant water potential ( ) dropped to -4 and -3.2 MPa, differently, the ATP in roots decreased 99.7% and 42%, respectively . When the rapidly dried soil was watered for up to 6 d, SWC and were found to recover to their normal levels, but ATP content in roots of P. orientalis and A. auriculiformis recovered by 10% and 23%, respectively. When plants of P. orientalis and A. auriculiformis were subjected to slow soil drying, respectively, as SWC was found to decrease from the normal level to 0.1 and 0.13 g·gDW-1, separately, dropped to - 2.5 and - 2 MPa, differently, the ATP content in roots decreased 98% and 38%, respectively. When the slowly dried soil was watered for up to 8 d, ATP levels in roots of P. orientalis and A, auriculiformis recovered by 30% and 24%, respectively. However, ATP concentrations in xylem sap were not directly influenced by either SWC or . The plot dots of xylem sap ATP concentration versus root ATP content were found to be distributed diagonally. It is concluded that ATP in roots is more sensitive in response to SWC changes than that to and root-sourced ATP is a source of that in xylem sap. When plants are subjected to slow soil drying, the ATP levels in both root and xylem sap are higher than that to rapid soil drying.     

Description of mechanism function about dehydration of cobalt oxalate dihydrate by multiple rates isotemperature method

0　IntroductionThetechnologyofthermalanalysishasbeenwidelyusedinthestudyofthermalbehaviorandthermalcharacterofsolidstatereaction ,theprimaryintentionofthermalanalysiskineticsistoestablishseparatevaluesofapparentactivationenergyE ,themostprobablemechanism g(α)andthepre exponentialfactorA ,meanwhilethedeterminationofg(α)hasgraduallybeenthefocusofthisfield .Inthisfield ,therearemostlygeneralkineticsmethodsused presently ,suchasCoats Redfern’s[1 ] integralmethod ,Achar’s[2 \〗differentialmet…     

A categorical interpretation of Yetter-Drinfel’d modules

It is known that any strict tensor category (C,⊗,I) can determine a strict braided tensor categoryZ(C), the centre ofC. WhenA is a finite Hopf algebra, Drinfel’d has proved thatZ( _AM) is equivalent to_D(A)M as a braided tensor category, where_AM is the left A-module category, andD(A) is the Drinfel’d double ofA. This is the categorical interpretation ofD(A). Z( _AM) is proved to be equivalent to the Yetter-Drinfel’d module category,_AYD ^A as a braided tensor category for any Hopf algebraA. Furthermore, for right A-comodule categoryM ^A, Z(M^A) is proved to be equivalent to the Yetter-Drinfel’d module category_AY D^A as a braided tensor category. But,in the two cases, the Yetter-Drinfel’d module category_AY D^A has different braided tensor structures.     

Preparation of (R)- and (S)-2-Allyl-1, 3, 2-dinaphtho (α, β) [d.f] dioxaborepin and their reactions with aldehydes

(R)- and(S)-2-Allyl-1,3,2-dinaphtho (α,β) [d.f] dioxaborepin ((R)-2 and(S)-2) have been first prepared by the reaction of(R)-(+)- or(S)-(−)-1, 1′-bi-2-naphthol and triallylborane in THF at room temperature, respectively.(S)-2 and(R)-2 are sensitive to moisture and oxygen in air and disproportionate easily to triallylborane and 1,1′-bi-2 naphthyl bis (1,1′-bi-2-naphtholborate) at ambient temperature. However, THF is a stabilizer for them. The reactions of(R)-2 or(S)-2 and some aliphetic or aromatic aldehydes in CH₂Cl₂ at −78°C for several hours afforded β-alkylenyl alcohols in up to 84.8%ee. Among them, optically active 1-(3, 5-dichlorophenyl)-3-butenol and 1-(2-methoxyphenyl)-3-butenol were first prepared Foundation item: Supported by the National Natural Science Foundation of China (29972033) Biography: Liu Dejun (1973), male, Ph. D, research direction: asymmetric synthesis     

Effects of La3+ and Gd3+ on Ca2+ influx in rat hepatoma H-35 cells

Effects of La³⁺ and Gd³⁺ on Ca²⁺ influx were investigated in rat hepatoma H-35 cells by measuring the initial rate of⁴⁵Ca²⁺ uptake. It was found that the maximum initial rate of Ca²⁺ uptake was increased six-to ten-fold at low concentrations of La³⁺ and Gd³⁺. Kinetic analyses by measuring the initial rate of Ca²⁺ influx at different external Ca²⁺ concentrations indicated the existence of two intracellular exchangeable components in the basal Ca²⁺ system, with low and high affinities for Ca²⁺, and only one class of Ca²⁺ binding sites was observed in the La³⁺-or Gd³⁺-treated cells. For high affinity, La³⁺ and Gd³⁺ increased both kinetic parametersK _m andV _max of basai Ca²⁺ influx. La³⁺ and Gd³⁺ compete directly with Ca²⁺ for Ca²⁺ binding site for low affinity. The kinetics is competitive.     

Effect of the control proliferation of astrocyte on the formation of glial scars by antisenseGFAP retrovirus

Astrocytes play an important role in the formation of glial scars. In order to investigate the effect of inhibitingGFAP gene expression on normal, reactive astrocytes and on glial scar formation, the efficiency of the recombinant antisenseGFAP retrovirus (PLBskG) on the growth, cell cycle, morphology andGFAP gene expression of astrocytesin vitro and on the formation of glial scarsin vivo has been studied by cell growth curves, flow cytometry, immunocytochemistry,in situ hybridization, RT-PCR and Southern blot. The results confirm the recombinant retrovirus (PLBskG) produced growth suppression and G1 arrest of the normal and injured astrocytes. The infected cells become round or ellipoid. The cell processes become fine or retracted. The intensity of staining ofGFAP is reduced. Expression ofGFAP mRNA is down regulated. However, in the control experiment, no obvious effects on the morphology or synthesis ofGFAP on cultured normal and scratched astrocytes infected by primary retrovirus vector (PLXSN) have been observed. The supernatant of PLBskG has been injected into an injured site by microinjectionin vivo. The number and process lengths of GFAP positive cells are obviously reduced around the injured site. The formation of the glial scar is inhibited, showing that the recombinant antisenseGFAP retrovirus can effectively inhibit the growth andGFAP expression of normal and injured astrocytesin vitro and the formation of glial scarin vivo. It is suggested thatGFAP plays an important role in glial scar formation.