Probing the location of displayed cytochrome b562 on amyloid by scanning tunnelling microscopy

Amyloid fibres displaying cytochrome b562 were probed using scanning tunnelling microscopy (STM) in vacuo. The cytochromes are electron transfer proteins containing a haem cofactor and could, in principle, mediate electron transfer between the tip and the gold substrate. If the core fibres were insulating and electron transfer within the 3D haem network was detected, then the electron transport properties of the fibre could be controlled by genetic engineering. Three kinds of STM images were obtained. At a low bias (<1.5 V) the fibres appeared as regions of low conductivity with no evidence of cytochrome mediated electron transfer. At a high bias, stable peaks in tunnelling current were observed for all three fibre species containing haem and one species of fibre that did not contain haem. In images of this kind, some of the current peaks were collinear and spaced around 10 nm apart over ranges longer than 100 nm, but background monomers complicate interpretation. Images of the third kind were rare (1 in 150 fibres); in these, fully conducting structures with the approximate dimensions of fibres were observed, suggesting the possibility of an intermittent conduction mechanism, for which a precedent exists in DNA. To test the conductivity, some fibres were immobilized with sputtered gold, and no evidence of conduction between the grains of gold was seen. In control experiments, a variation of monomeric cytochrome b562 was not detected by STM, which was attributed to low adhesion, whereas a monomeric multi-haem protein, GSU1996, was readily imaged. We conclude that the fibre superstructure may be intermittently conducting, that the cytochromes have been seen within the fibres and that they are too far apart for detectable current flow between sites to occur. We predict that GSU1996, being 10 nm long, is more likely to mediate successful electron transfer along the fibre as well as being more readily detectable when displayed from amyloid.

Altering the ordering and disordering of a triangular nanographene at room temperature

Molecular self-organization has the potential to serve as an efficient and versatile tool for the spontaneous creation of low-dimensional nanostructures on surfaces. We demonstrate how the subtle balance between intermolecular interactions and molecule-surface interactions can be altered by modifying the environment or through manipulation by means of the tip in a scanning tunnelling microscope (STM) at room temperature. We show how this leads to the distinctive ordering and disordering of a triangular nanographene molecule, the trizigzag-hexa-peri-hexabenzocoronenes-phenyl-6 (trizigzagHBC-Ph6), on two different surfaces: graphite and Au(111). The assembly of submonolayer films on graphite reveals a sixfold packing symmetry under UHV conditions, whereas at the graphite-phenyloctane interface, they reorganize into a fourfold packing symmetry, mediated by the solvent molecules. On Au(111) under UHV conditions in the multilayer films we investigated, although disorder prevails with the molecules being randomly distributed, their packing behaviour can be altered by the scanning motion of the tip. The asymmetric diode-like current-voltage characteristics of the molecules are retained when deposited on both substrates. This paper highlights the importance of the surrounding medium and any external stimulus in influencing the molecular organization process, and offers a unique approach for controlling the assembly of molecules at a desired location on a substrate.

PIK3CA exon 20 mutations as a potential biomarker for resistance to anti-EGFR monoclonal antibodies in KRAS wild-type metastatic colorectal cancer: a systematic review and meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis to dissect the association between PIK3CA mutations and resistance to anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MoAbs) according to PIK3CA exon of mutations in metastatic colorectal cancer (mCRC).

METHODS

We systematically identified studies exploring the association between PIK3CA mutations and clinical outcomes of mCRC patients treated with anti-EGFR MoAbs. The primary clinical outcomes included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). The pooled relative risk (RR) or hazard ratio (HR) was estimated by using fixed effect model or random effect model according to heterogeneity between studies.

RESULTS

Thirteen studies were considered eligible, with 576 mCRC patients included. In KRAS wild-type mCRC patients, we observed a lower ORR in patients with PIK3CA exon 20 mutations [3 studies, 377 patients; ORR = 0% versus 37%; RR = 0.25; 95% confidence interval (CI) 0.05-1.19; P = 0.082], although the result was not statistically significant because of the small sample size. Only one study provided survival data according to the PIK3CA exon of the mutations, in which PIK3CA exon 20 mutations were statistically significantly associated with shorter PFS (HR = 2.52; 95% CI 1.33-4.78; P = 0.013) and OS (HR = 3.29; 95% CI 1.60-6.74; P = 0.006) in KRAS wild-type mCRC patients treated with anti-EGFR MoAbs. The predictive power of exon 20 mutation is greater than exon 9 mutations and all exons mutations in terms of ORR, PFS, and OS.

CONCLUSION

These analyses suggest that PIK3CA exon 20 mutations may be a potential biomarker for resistance to anti-EGFR MoAbs in KRAS wild-type mCRC.

Ultrabroadband optical circular polarizers consisting of double-helical nanowire structures

Recently, it was demonstrated by Gansel et al. [Science 325, 1513 (2009)] that 3D single-helical metamaterials can serve as broadband circular polarizers in the IR range. In this study, we propose a structured metamaterial with double-helical nanowires to construct circular polarizers with boarder wavelength bands in the visible-light and near-IR regions. Using the finite-difference time-domain method, we confirmed that the circular polarizers with the double-helical structures have operation bands more than 50% broader than those of the single-helical structures.

Complete mitochondrial genome of Cabot's tragopan, Tragopan caboti (Galliformes: Phasianidae)

Cabot's tragopan, Tragopan caboti, is a globally threatened pheasant endemic to southeast China. The complete mitochondrial genome of Cabot's tragopan was sequenced. The circular genome contains 16,727 bp, encoding a standard set of 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes, plus the putative control region, a structure very similar to that of other Galliformes. As found in other vertebrates, most of these genes code on the H-strand, except for the NADH dehydrogenase subunit 6 (nad6) and eight tRNA genes (Gln, Ala, Asn, Cys, Tyr, Ser(UCN), Pro, Glu). All protein-coding genes initiated with ATG, except for cox1, which began with GTG, and had a strong skew of C vs G (GC skew = -0.29 to -0.73). One extra 'C' nucleotide was found in the NADH dehydrogenase subunit 3 (nad3). All the tRNA gene sequences have the potential to fold into typical cloverleaf secondary structures. Conserved sequences in three domains were identified within the control region (D-loop). These results provide basic information for phylogenetic analyses among Galliform birds, and especially Tragopan species.

Modeling local structure using crystal field and spin Hamiltonian parameters: the tetragonal Fe(K)(3+)-O(I)(2-) defect center in KTaO(3) crystal

The local structure and the spin Hamiltonian (SH) parameters, including the zero-field-splitting (ZFS) parameters D and (a+2F/3), and the Zeeman g factors [Formula: see text] and [Formula: see text], are theoretically investigated for the Fe(K)(3+)-O(I)(2-) center in KTaO(3) crystal. The microscopic SH (MSH) parameters are modeled within the framework of the crystal field (CF) theory employing the CF analysis (CFA) package, which also incorporates the MSH modules. Our approach takes into account the spin-orbit interaction as well as the spin-spin and spin-other-orbit interactions omitted in previous studies. The superposition model (SPM) calculations are carried out to provide input CF parameters for the CFA/MSH package. The combined SPM-CFA/MSH approach is used to consider various structural models for the Fe(K)(3+)-O(I)(2-) defect center in KTaO(3). This modeling reveals that the off-center displacement of the Fe(3+) ions, Δ(1)(Fe(3+)), combined with an inward relaxation of the nearest oxygen ligands, Δ(2)(O(2-)), and the existence of the interstitial oxygen O(I)(2-) give rise to a strong tetragonal crystal field. This finding may explain the large ZFS experimentally observed for the Fe(K)(3+)-O(I)(2-) center in KTaO(3). Matching the theoretical MSH predictions with the available structural data as well as electron magnetic resonance (EMR) and optical spectroscopy data enables predicting reasonable ranges of values of Δ(1)(Fe(3+)) and Δ(2)(O(2-)) as well as the possible location of O(I)(2-) ligands around Fe(3+) ions in KTaO(3). The defect structure model obtained using the SPM-CFA/MSH approach reproduces very well the ranges of the experimental SH parameters D, [Formula: see text] and [Formula: see text] and importantly yields not only the correct magnitude of D but also the sign, unlike previous studies. More reliable predictions may be achieved when experimental data on (a+2F/3) and/or crystal field energy levels become available. Comparison of our results with those arising from alternative models existing in the literature indicates considerable advantages of our method and presumably higher reliability of our predictions.

Broadband nanowire-grid polarizers in ultraviolet-visible-near-infrared regions

Broadband nanowire-grid polarizers were designed and numerically simulated using the finite difference time domain (FDTD) method. Using a broadband stimulation source, optical properties of the polarizers were analyzed in the ultraviolet (UV)-visible-near infrared (NIR) regions. Specifically, the extinction ratios and optical transmittances of transverse magnetic (TM) and transverse electric (TE) modes were characterized for different metal materials and geometrical parameters including wire-grid periods, metal-wire fill ratios, and spacing between wire-grid layers. Based on the simulation results, an extra broadband polarizer with an average extinction ratio higher than 70 dB and transmission efficiency over 64% in the range of 0.3 to 5 mum was proposed.

Performance evaluation of a dental handpiece in simulation of clinical finishing using a novel 2DOF in vitro apparatus

This paper reports on the performance evaluation of a dental handpiece in simulation of clinical finishing using a novel two-degrees-of-freedom (2DOF) in vitro apparatus. The instrumented apparatus consisted of a two-dimensional computer-controlled coordinate worktable carrying a dental handpiece, a piezoelectric force dynamometer, and a high-speed data acquisition and signal conditioning system for simulating the clinical operations and monitoring the dental finishing processes. The performance of the dental handpiece was experimentally evaluated with respect to rotational speed, torque, and specific finishing energy under the applied clinical finishing conditions. The results show that the rotational speeds of the dental handpiece decreased by increasing either the depth of cut or the feed rate at a constant clinically applied air pressure and water flowrate. They also decreased when increasing both the tangential and normal finishing forces. The specific finishing energy decreased with an increase in either depth of cut or feed rate, while the finishing torque increased as either the depth of cut or the feed rate was increased. Implications of these results were to provide guidance for proper applications of dental handpieces in clinical practice.

Anaerobic uptake of phosphate in an anaerobic-aerobic granular sludge sequencing batch reactor

An unusual phenomenon of anaerobic phosphate uptake under alternating anaerobic/aerobic condition was observed in a granular sludge sequencing batch reactor, fed with acetate as sole organic substrate. Anaerobic phosphate uptake efficiencies remained at 50-70% as the influent P/COD was increased from 2/100 to 4/100, and results showed that anaerobic uptake of phosphate was correlated with anaerobic absorption of acetate. Excluding the main possibility of chemical phosphate removal, it appeared that phosphate uptake during the anaerobic phase was associated with organisms enriched in the reactor. Moreover, results indicated that intracellular glycogen was used as the main energy source of organics anaerobic absorption and intracellular polymers storage. Measuring and analysing the variation of phosphate, organic substrate, intracellular glycogen and pH in the anaerobic phase, a preliminary explanation was developed that anaerobic uptake of phosphate was the demand of intracellular glycogen degradation, and extracellular phosphate was transported to intracellular by pH gradient-sensitive phosphate carrier protein.

Effect of p-glycoprotein inhibitor combinations on drug efflux from rat brain microvessel endothelial cells

In an effort to develop a clinically useful approach to inhibit the drug efflux across the blood brain barrier (BBB) mediated by P-glycoprotein (P-gp), the combined inhibitory effect of four P-gp inhibitors: cyclosporin A (CsA), verapamil (Ver), tetrandrine (Tet) and doxorubicin (Dox), was evaluated by determining the intracellular concentration of rhodamine 123 in in vitro cultured rat brain microvessel endothelial cells (BMEC). The results showed that CsA combined with Ver or Tet synergistically inhibited P-gp mediated efflux of Rh123 from rat BMEC, suggesting that the combined application of P-gp inhibitors would possibly be a useful approach to increase drug concentration in brain tissues, enhance the therapeutic effect and reduce the toxicity of drugs.

Diet and ovarian cancer risk: a case-control study in China

This case-control study, conducted in Zhejiang, China during 1999-2000, investigated whether dietary factors have an aetiological association with ovarian cancer. Cases were 254 patients with histologically confirmed epithelial ovary cancer. The 652 controls comprised 340 hospital visitors, 261 non-neoplasm hospital outpatients without long-term diet modifications and 51 women recruited from the community. A validated food frequency questionnaire was used to measure the habitual diet of cases and controls. The risks of ovarian cancer for the dietary factors were assessed by adjusted odds ratios based on multivariate logistic regression analysis, accounting for potential confounding demographic, lifestyle, familial factors and hormonal status, family ovarian cancer history and total energy intake. The ovarian cancer risk declined with increasing consumption of vegetables and fruits but vice versa with high intakes of animal fat and salted vegetables. The adjusted upper quartile odds ratio compared to the lower quartile was 0.24 (0.1-0.5) for vegetables, 0.36 (0.2-0.7) for fruits, 4.6 (2.2-9.3) for animal fat and 3.4 (2.0-5.8) for preserved (salted) vegetables with significant dose-response relationship. The risk of ovarian cancer also appeared to increase for those women preferring fat, fried, cured and smoked food.

Antitumor Agents. 211. Fluorinated 2-phenyl-4-quinolone derivatives as antimitotic antitumor agents

Fluorinated 2-phenyl-4-quinolone derivatives were synthesized and evaluated in National Cancer Institute's 60 human tumor cell line in vitro screen. From the results, the ketone moiety plays an essential role in activity. Among the compounds tested, 2'-fluoro-6-pyrrol-2-phenyl-4-quinolone (13) exhibited the most potent cytotoxic activities (log GI(50) < -8.00) against renal and melanoma tumor cell lines. Compound 13 was also a potent inhibitor of tubulin polymerization (IC(50) = 0.46 microM) and of radiolabeled colchicine binding to tubulin, with activities comparable to those of the potent antimitotic natural products colchicine, podophyllotoxin, and combretastatin A-4.

A new type of class I bacterial 5-enopyruvylshikimate-3-phosphate synthase mutants with enhanced tolerance to glyphosate

Glyphosate or Roundup is the most extensively used herbicide for broad-spectrum control of weeds. Glyphosate inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), a key enzyme in the aromatic amino acid biosynthetic pathway in microorganisms and plants. Applying the staggered extension process, we randomly mutated and recombined the aroA genes of Salmonella typhimurium and Escherichia coli to obtain four variants that exhibit significantly enhanced tolerance to glyphosate. All four mutants are chimeras of the two parental genes and, in addition, three of them carry one or more de novo point mutations. None of the amino acid substitutions in the mutants was in a position previously known to be important for catalysis or substrate binding. Kinetic analysis of EPSPS activity from these mutants indicated that the tolerance was attributed to a 2-10-fold increased specific activity, 0.4-8-fold reduced affinity to glyphosate, and 2.5-19-fold decreased K(m) for phosphoenolpyruvate. Such mutants will be instrumental for the structural and function study of the enzyme and for the generation of transgenic crops resistant to the herbicide.

Coexpression of guanylate kinase with thymidine kinase enhances prodrug cell killing in vitro and suppresses vascular smooth muscle cell proliferation in vivo

Herpes simplex virus-thymidine kinase (HSV-TK) phosphorylates the prodrugs ganciclovir (GCV) and acyclovir (ACV), leading to disruption of DNA synthesis and inhibition of cell proliferation. HSV-TK vectors have been successfully employed in cardiovascular and cancer gene therapy. Activation of GCV and ACV, after an initial phosphorylation step by the viral thymidine kinase, is carried out by guanylate kinase. We reasoned that coexpression of guanylate kinase (GK) with HSV-TK would augment phosphorylation of GCV or ACV, leading to increased cell killing. To test this hypothesis, a vector expressing TK with GK (TKciteGK) was developed and tested on vascular smooth muscle cells (vsmcs) in vitro and in vivo. Compared to HSV-TK vectors, killing of vascular cells transduced with TKciteGK and exposed to GCV was significantly increased (P = 0.03). The TKciteGK construct was evaluated with three promoters: CMV, EF1alpha, and SM22alpha. TKciteGK expression driven by a CMV promoter induced cell killing more effectively than SM22alpha or EF1alpha promoters in primary vsmcs. Based upon these in vitro findings, TKciteGK vectors with a CMV promoter were tested in two animal models of cardiovascular disease: balloon angioplasty and stent deployment in pig arteries. Following vascular injury, expression of CMV-TKciteGK with GCV significantly reduced vsmc proliferation and intimal lesion formation compared to control vectors with GCV. In the angioplasty model, there was an 80% reduction in intima-to-media area ratio (P = 0.0002). These findings were paralleled in a stent model with 66% reduction in intimal lesions (P = 0.006). Coexpression of GK with TK increases cell killing and permits administration of GCV at lower doses. These modifications in TKciteGK vectors and GCV showed enhanced efficacy at lower prodrug doses, leading to improved safety for cardiovascular gene therapy.

[A genetically modified japonica restorer line, C418-Xa21, and its hybrid rice with bacterial blight resistance]

The cloned bacterial blight (BB) resistance gene Xa21 was transferred into C418, a major restorer line of japonica hybrid rice in China, using an Agrobacterium-mediated system. The integrated single copy of transgene displayed a 3:1 segregation ratio in T1 generation in PCR and resistance analyses. The transgenic homozygous C418-Xa21 lines were selected in T2 generation through PCR and resistance analyses. The selected transgenic restorer lines were then crossed with a commonly used sterile line, TijinA, to produce Xa21 transgenic hybrid rice. Molecular analysis revealed that the produced hybrid rice, named as Tiyou418-Xa21, inherited the transgene. Both C418-Xa21 and Tiyou418-Xa21 plants displayed high resistance with a broad spectrum to Xoo races and maintained their normal elite agronomic characters. We also observed that the resistance level of Tiyou418-Xa21 was obviously higher than that of C418-Xa21 which may be attributed to their differences in genetic background. The propagation of this BB resistant hybrid variety with the transgene Xa21 with extend hybrid rice production in north China.

Antitumor Agents. Part 204: Synthesis and Biological Evaluation of Substituted 2-Aryl Quinazolinones

A series of 2',3',4',6,7-substituted 2-aryl quinazolinones were synthesized and evaluated for biological activity. Among them, 17 displayed significant growth inhibitory action against a panel of tumor cell lines. Compound 17 was also a potent inhibitor of tubulin polymerization. Compounds 8-10 displayed selective activity against P-gp-expressing epidermoid carcinoma of the asopharynx.

Growth response of Sesbania rostrata and S. cannabina to sludge-amended lead/zinc mine tailings. A greenhouse study

Legumes are ideal for revegetation of metal-mined wastelands which lack nitrogen (N). A greenhouse study was conducted to investigate the feasibility of using Sesbania rostrata and S. cannabina for the reclamation of lead/zinc (Pb/Zn) mine tailings and to evaluate the effects of organic amendment using sewage sludge (0%, 25%, 50%, and 75%, v/v). The results showed that both species could continue to grow on the highly toxic tailings substrata for at least 80 days, although their growth suffered from adverse effects. That S. rostrata with stem and root nodules had better growth (biomass, growth rates, and biomass of nodules) than S. cannabina suggested that S. rostrata is a better choice as a pioneer species for revegetation of the mine tailings. Stem nodules had less obvious adverse effects imposed by tailings than root nodules. Application of sewage sludge increased contents of total carbon (C), N, phosphorus (P), and potassium (K), and reduced total Zn, Pb, Cd, and DTPA-extractable Pb and Cd in tailings substrata. These, in turn, reduced metal (Zn, Pb, and Cd) uptake and accumulation in plant tissues, and improved plant growth performance, including biomass, growth rates, stem nodulation. Fifty percent (v/v) of sludge application rate was the best loading rate for plant growth.

Spatial distribution analysis on climatic variables in northeast China

Information ecology is a new research area of modern ecology. Here describes the spatial distribution analysis methods of four sorts of climatic variables, i.e. temperature, precipitation, relative humidity and sunshine fraction in Northeast China. First, digital terrain models was built with large-scale maps and vector data. Then trend surface analysis and interpolation method were used to analyze the spatial distribution of these four kinds of climatic variables at three temporal scale: (1) monthly data; (2) mean monthly data of thirty years, and (3) mean annual data of thirty years. Ecological information system were used for graphics analysis on the spatial distribution of these climatic variables.

[High performance liquid chromatography/electrospray ionization mass spectrometric characterization of recombinant L-asparaginase II]

AIM

To characterize the primary structure of recombinant L-asparaginase II product.

METHODS

The molecular weight of the protein was measured by pneumatically-assisted electrospray ionization mass spectrometry with flow injection mode. Subsequently, tryptic peptide mapping was performed by high performance liquid chromatography on a C8 column with tandem UV and MS detection. An easy-to-use and simple denaturation process with trichloroacetic acid was conducted prior to tryptic digest so as to release the digest resistance from the protein structure. The amino acid sequences of the tryptic peptides were elucidated based on their in-source collision-induced dissociation spectra.

RESULTS

The measured molecular mass was different from the theoretical value. Three amino acid variations were unambiguously detected along the peptide backbone derived from the gene-encoding sequence.

CONCLUSION

This paper revealed that LC/ESI/MS had provided a promising and robust technique in primary structure analysis and quality control of DNA-derived recombinant protein pharmaceuticals.

[Synthesis of droloxifene citrate and its new bioactivity]

AIM

To investigate a feasible synthetic procedure of droloxifene and study on its new bioactivities.

METHODS AND RESULTS

Droloxifene was synthesized using methoxybenzene and phenylacetic acid as starting materials, via Friedel-Crafts acylation, alkylation, demethylation, etherification, Grignard addition, elimination-dehydration, conversing configuration and forming citrate, totally 8 steps, overall yield 14.7% (9.2%). By pharmacological test, droloxifene citrate shows two new bioactivities: (1) obvious effect on reversing the MDR of K562/A02 cells and modulating mdrl, GST pi and TopoII alpha expression. (2) inducing apoptosis in cultured rat luteal cell.

CONCLUSION

The improved synthetic procedure is shorter than the reported method by two steps and has advantages of simple separation, purification and conversion of configuration; easily available starting materials and reagents; concise operation. Two new bioactivities on reversing MDR and inducing apoptosis of luteal cell offered a clue in new drugs research and widened clinic application of droloxifene.

Development of a preventive vaccine for Ebola virus infection in primates

Outbreaks of haemorrhagic fever caused by the Ebola virus are associated with high mortality rates that are a distinguishing feature of this human pathogen. The highest lethality is associated with the Zaire subtype, one of four strains identified to date. Its rapid progression allows little opportunity to develop natural immunity, and there is currently no effective anti-viral therapy. Therefore, vaccination offers a promising intervention to prevent infection and limit spread. Here we describe a highly effective vaccine strategy for Ebola virus infection in non-human primates. A combination of DNA immunization and boosting with adenoviral vectors that encode viral proteins generated cellular and humoral immunity in cynomolgus macaques. Challenge with a lethal dose of the highly pathogenic, wild-type, 1976 Mayinga strain of Ebola Zaire virus resulted in uniform infection in controls, who progressed to a moribund state and death in less than one week. In contrast, all vaccinated animals were asymptomatic for more than six months, with no detectable virus after the initial challenge. These findings demonstrate that it is possible to develop a preventive vaccine against Ebola virus infection in primates.

SM22alpha promoter targets gene expression to vascular smooth muscle cells in vitro and in vivo

BACKGROUND

Gene transfer into vascular smooth muscle cells (vsmcs) holds promise for studying the pathogenesis of arterial disorders. However, a potential limitation of vectors with heterologous promoters is organ toxicity resulting from unrestricted transgene expression. Vascular smooth muscle cell-specific gene expression could increase the safety of vectors for vascular diseases.

MATERIALS AND METHODS

To develop vectors that target gene expression to vsmcs, we constructed vectors encoding human placental alkaline phosphatase (hpAP) and chloramphenicol transferase (CAT) driven by a 441-bp region of the murine SM22alpha promoter (AdSM22alpha-hpAP).

RESULTS

Transfection of AdSM22alpha-hpAP into vascular and nonvascular cells resulted in the expression of alkaline phosphatase (AP) in primary arterial and venous smcs, but not in primary endothelial cells or National Institutes of Health (NIH) 3T3 cells. Expression of AP was observed on 32.5 +/- 1.4% of primary pig vsmcs-infected AdSM22alpha-hpAP at a multiplicity of infection (MOI) of 500; whereas, infection with AdCMV-hpAP resulted in 100 +/- 0.0% expression at a MOI of 250. In vitro, expression from the heterologous cytomegalovirus (CMV) promoter was approximately 10(3)-fold higher in vsmcs, compared with the SM22alpha promoter. Following introduction of AdSM22alpha-hpAP vectors into balloon-injured pig arteries, AP recombinant protein was detected in neointimal (2.23 +/- 1.14%) and medial (0.56 +/- 0.21%) smcs, but not in endothelial or adventitial cells. In contrast, AdCMV-hpAP vectors led to AP expression in intimal endothelial and smcs cells (39.14 +/- 10.09%) and medial smcs (2.84 +/- 1.05%). AP expression was not observed in endothelial or vsmcs following transfection with the control vector, adenoviral vector lacking E1 (AddeltaE1).

CONCLUSIONS

The SM22alpha promoter programs recombinant gene expression exclusively to vascular smcs in vitro and in vivo. Although expression levels are lower than with heterologous promoters, these vectors may provide a safe and effective tool for gene therapy of vascular diseases.

[Synthesis and antineoplastic activity of N,N'-disubstituted phenyl-3,6-dimethyl-1,4-dihydro-1,2,4,5-tetrazine-1,4-dicarboamide derivatives]

AIM

To search for antineoplastic drugs with fewer side effects and improved activities, using tetrazine derivatives with different substituted groups in their phenyl rings.

METHODS

The title compounds have been synthesized by reacting 3,6-dimethyl-1,6-dihydro-1,2,4,5-tetrazine with substituted phenyl isocyanates in the presence of p-dimethylamino pyridine as catalyst.

RESULTS

Eighteen new N,N'-disubstituted phenyl-3,6-dimethyl-1,4-dihydro-1,2,4,5-tetrazine-1,4-dicarboamides have been synthesized. Their structures have been confirmed by IR, 1HNMR and elemental analysis. The antineoplastic activities were screened. The structure-activity relationship has also been studied.

CONCLUSION

The meta-substituted tetrazine derivatives showed marked antitumor activities against P388 and A-549 when electronic effect constants and hydrophobic constants of their substitutents are in a certain range.