bluuebunny/crossref_metadata_2025 huggingface dataset:
Westward movement of eddies into the Gulf of Aden from the Arabian Sea
Authors: Al Saafani M. A. , Shenoi S. S. C. , Shankar D. , Aparna M. , Kurian J. , Durand F. , Vinayachandran P. N.
Published: November 2007

Sea level anomalies (SLA) from satellite altimetry (1993–2003) reveal the westward movement of mesoscale eddies in the Gulf of Aden. Inside the gulf the eddies move at a speed of ∼6.0–8.5 cm s−1, comparable to the first‐mode baroclinic Rossby wave speed of 7.2 cm s−1. We show that the eddies, which enter the gulf from the Arabian Sea, owe their existence to more than one mechanism. Local Ekman pumping in the western Arabian Sea is important during the summer monsoon (June–September). In May and during the latter half of the summer monsoon (late July to September) and the fall intermonsoon (October), the dominant mechanism is the generation of eddies by the instabilities in the Somali Current and the large eddies associated with it (Great Whirl and Socotra eddy). During the winter monsoon (November–April) the dominant mechanism involves the westward propagating Rossby waves generated either in the Arabian Sea by Ekman pumping or along the west coast of India by poleward propagating Kelvin waves. These Rossby waves from the Arabian Sea propagate slower on entering the gulf because of a shallower thermocline in the gulf. Analysis shows that the SLA signal consists of low (annual and subannual) and high (∼100–180 d) frequencies. The low‐frequency signal (mainly annual) shows a discontinuity between 52°E and 60°E. Though the high‐frequency signal is seen at all longitudes, a wavelet analysis shows that it was significant only west of 60°E. An energy analysis, based on model simulations, suggests that barotropic instabilities are important during the entire year and that baroclinic instabilities are also important during the summer monsoon.
Carbonaceous and inorganic species in atmospheric aerosols during wintertime over urban and high‐altitude sites in North India
Authors: Rengarajan R. , Sarin M. M. , Sudheer A. K.
Published: November 2007

Synchronous sampling of bulk‐aerosols, carried out during wintertime from the two strategically located sites in North India, reveals that total suspended particulates (TSP) over an urban site (Hisar: 29.2°N 75.7°E; 219 m asl) ranged from 67 to 396 μg m−3; in contrast, TSP at Manora Peak (a high‐altitude station: 29.4°N 79.5°E; 1950 m asl) was relatively low (range: 13.7 to 42.7 μg m−3). At Hisar, on average, water‐soluble ionic species (WSIS, range: 14.1 to 78.3 μg m−3) contribute nearly one‐fourth by weight to TSP, with dominant contribution from SO42−, NO3− and NH4+. The time series analysis over a span of 30 days shows somewhat uniform distribution of organic carbon/elemental carbon (OC/EC) ratio centering around 8.5 ± 2.2 at this urban site; and the water‐soluble organic components (WSOC range: 6.7 to 42.0 μg m−3) account for 11.5 % to the TSP concentration. Both WSOC and OC exhibit significant positive correlation with water‐soluble K+ (r = 0.88 and 0.79 respectively), suggesting their dominant contribution from biomass burning. At Manora Peak, the chemical composition of ambient aerosols show characteristically lower abundances of WSIS (range: 2.0 to 9.9 μg m−3) and WSOC (range: 1.4 to 6.0 μg m−3); together they account for one‐third of the TSP. The characteristic low abundances of OC (range: 2.8 to 6.9 μg C m−3) and EC (range: 0.34 to 1.4 μg C m−3) at this high‐altitude site and their significant correlation with K+ and SO42− suggest contribution from long‐range transport of anthropogenic species. This study represents a first comprehensive data set for documenting the chemical characteristics of ambient aerosols and source apportionment of EC, OC, WSIS and mineral dust over urban and high‐altitude sites in north India, an important data set required for the south Asian region. If the observed OC/EC ratios far greater than ∼2 (unlike reported values in the literature for urban sites) and the semi‐empirical estimates of secondary OC are typical of the annual average abundances in the ambient aerosols over north India, then the temporal and regional analyses of primary and secondary OC using the existing emission models require reassessment for this region.
Observation and analysis of a large amplitude mountain wave event over the Antarctic peninsula
Authors: Alexander M. Joan , Teitelbaum Hector
Published: November 2007

We use measurements from the Atmospheric Infrared Sounder (AIRS) on the AQUA satellite to observe the 3‐dimensional structure of a gravity wave event over the Antarctic peninsula, and determine the horizontal and vertical wavelengths, propagation direction, and temperature amplitude, and from these we estimate wave momentum flux. Using theoretical knowledge of the weighting functions and radiative transfer for AIRS radiance measurements at temperature sensitive channels in the infrared, we derive a method of estimating wave temperature amplitude directly from the radiance measurements. Comparison of the radiance‐based temperature amplitudes to the temperature amplitude in AIRS retrieved temperature fields shows close agreement. Because the radiances have 3‐times better horizontal resolution than the retrievals, our analysis suggests we can routinely observe important geophysical properties of waves with horizontal wavelengths as short as 80 km using AIRS radiances. We further analyze a nearly identical wave event appearing in the European Centre for Medium Range Forecasts (ECMWF) temperature and wind fields from both assimilation and forecast data. Analysis of the ECMWF data and nearby radiosonde wind profiles allows the interpretation as a mountain wave event forced by flow over the topography of the Antarctic peninsula.
Assimilation of current measurements into a circulation model of Lake Michigan
Authors: Zhang Zepu , Beletsky Dmitry , Schwab David J. , Stein Michael L.
Published: November 2007

We present a method for assimilating current observations into a two‐dimensional circulation model of Lake Michigan, based on the Princeton Ocean Model (POM) and driven by observed winds. Because measurements of surface level are not available, we require that the point‐wise update to the forecast horizontal current does not change the forecast surface level. This requirement makes it possible to represent the current updates by a stream function. Given an appropriate covariance model of this stream function, the current updates are calculated by kriging interpolation using the observations and the corresponding model forecast. It is further required that the current updates do not create cross‐shore flows; this is represented by the stream function being constant along the coastline and is enforced by incorporating pseudo coastal data into the interpolation. This eliminates the need to construct complex spatial covariance models for the stream function. The method also accommodates observational errors. Results show that the method successfully melds observations into the model, and the influence of data assimilation propagates in space and time.
Radiation mitigation at the Moon by the terrestrial magnetosphere
Authors: Winglee R. M. , Harnett E. M.
Published: November 2007

The Moon spends 25% of its orbit within the terrestrial magnetosphere. The magnetic field from the terrestrial magnetosphere can potentially provide radiation shielding from solar energetic particle events and lower energy galactic cosmic rays, which can be a significant hazard during extra‐vehicle activities or during human exploration of the lunar surface. The level of shielding provided by the terrestrial magnetosphere is calculated in conjunction with 3D multi‐fluid simulations of the terrestrial magnetospheres. It is shown that the level of shielding is dependent on IMF orientation and location of the lunar base. The natural terrain could be used to augment the terrestrial shielding for an equatorial lunar base. A polar lunar base would be exposed to twice as much radiation. But in both cases shielding of GeV particles is possible, with the upper range depending on the prevailing solar wind conditions.
Validity of SeaDAS water constituents retrieval algorithms in Australian tropical coastal waters
Authors: Qin Yi , Brando Vittorio E. , Dekker Arnold G. , Blondeau‐Patissier David
Published: November 2007

This paper reports an assessment of the performance of the seven global empirical and semi‐analytical chlorophyll and bulk IOP retrieval algorithms implemented in SeaDAS, for the local conditions in tropical waters off the Australian northeast coast. An approach based on radiative transfer simulations was used providing systematic assessments. The study shows that when coloured dissolved organic matter (CDOM) and non‐algal particle (NAP) concentrations are low, the seven algorithms tested, as expected, can retrieve chlorophyll with an error of, at best, 75% for 80–90% of the cases. The accuracy generally degrades rapidly with increasing CDOM and NAP concentrations. For the semi‐analytical algorithms (bulk IOP retrieval enabled), the QAA algorithm achieved a better result at retrieving the total absorption, a, backscattering, bb and backscattering by particles, bbp. However, none of the algorithms can break down the total absorption into components with reasonable accuracy. The study indicates that without incorporating regional and seasonal knowledge of specific IOPs the accuracy in water constituent retrievals from remote sensing is poor, hindering the use of remote sensing in water quality management.
Tethys: Lithospheric thickness and heat flux from flexurally supported topography at Ithaca Chasma
Authors: Giese Bernd , Wagner Roland , Neukum Gerhard , Helfenstein Paul , Thomas Peter C.
Published: November 2007

We have identified flexural uplift along the flanks of Tethys' Ithaca Chasma using Cassini stereo‐derived topography. Modeling the topography as a broken elastic plate yields an effective elastic lithospheric thickness in the range of 5–7 km and, combined with the strength envelope of the lithosphere, a mechanical lithospheric thickness of 16–20 km. Surface heat fluxes are 18–30 mW/m2 for adopted strain rates of 10−17–10−14 s−1. These heat fluxes are more than 4 times higher than those calculated from thermal history models of Tethys and indicate a strongly enhanced local heat flux associated with the formation of Ithaca Chasma. We use crater‐size frequency counts and a lunar‐like impact chronology to fix the time of formation of Ithaca Chasma at 4 Ga from present‐day. Ithaca Chasma predates the Odysseus basin and thus could not have been formed by this impact feature.
Environmental aerosol chamber studies of extinction spectra of mineral dust aerosol components: Broadband IR‐UV extinction spectra
Authors: Mogili Praveen K. , Yang K. H. , Young Mark A. , Kleiber Paul D. , Grassian Vicki H.
Published: November 2007

Mineral dust aerosol plays an important role in the Earth's radiative budget on both regional and global scales. To better understand the impact of this component of the Earth's atmosphere, the extinction spectra for several key components of mineral dust aerosol have been measured in an environmental aerosol reaction chamber. The extinction spectra are measured over a broad wavelength range, which includes both IR (650 to 5000 cm−1) and UV‐Vis (12,500 to 40,000 cm−1) spectral regions. Experimental data are compared with Mie theory simulations derived from available literature optical constants. In a few cases, we have needed to modify the published optical constant data sets to ensure Kramers‐Kronig consistency. In general, the Mie‐based simulations are in excellent agreement with experimental data over the full IR‐UV spectral range, except in the immediate neighborhood of the IR resonance absorption lines where particle shape effects on the resonance line profiles can be significant.
Modeling impact cratering in layered surfaces
Authors: Senft Laurel E. , Stewart Sarah T.
Published: November 2007

Impact craters are potentially powerful tools for probing large‐scale structure beneath planetary surfaces. However, the details of how target structure affects the impact cratering process and final crater forms remain poorly understood. Here, we present a study of cratering in layered surfaces using numerical simulations. We implement the rheologic model for geologic materials described by Collins et al. (2004) into the shock physics code CTH; this model includes pressure, temperature, and damage effects on strength as well the option to include acoustic fluidization. The model produces reasonable final crater shapes and damaged zones from laboratory to planetary scales. We show the effects of varying material strength parameters and discuss choosing appropriate strength parameters for laboratory and planetary situations. Results for cratering into idealized terrains with layers of differing material strength are presented. The presence of such layers in the target can significantly alter the ejecta curtain structure and the final crater morphology. Finally, we reproduce the morphologic variations that are observed in small lunar craters by modeling a weak regolith overlying competent rock.
Diffraction of plane waves incident on a grated dielectric slab: An entire domain integral equation analysis
Authors: Tsitsas Nikolaos L. , Uzunoglu Nikolaos K. , Kaklamani Dimitra I.
Published: November 2007

Diffraction of electromagnetic waves by periodic grating waveguides is investigated by using a rigorous integral equation method, which combines semianalytical techniques and the Method of Moments with entire domain basis functions. The electric field integral equation is employed with unknown function the electric field on the grooves. This equation is subsequently solved by applying an entire domain Galerkin's technique. The proposed analysis provides high numerical stability and controllable accuracy. All the involved computations are analytically carried out, leading to an analytic solution with the sole approximation of the final truncation of the expansion functions sets. The computed results exhibit superior accuracy and numerical efficiency compared with those already derived by applying different methods. The effect of the incident field's and grating's characteristics on the diffraction process as well as the grating structure's efficient operation as a narrow band reflection filter are thoroughly investigated. The numerical results obtained provide design guidelines, which may be exploited appropriately in the development of millimeter and optical waveguide structures.
Anomalies of subdiffractive guided wave propagation along metamaterial nanocomponents
Authors: Alù Andrea , Engheta Nader
Published: November 2007

We describe our recent results on some of the anomalous propagation properties of subdiffractive guided modes along plasmonic or metamaterial cylindrical waveguides with core‐shell structures, with particular attention to the design of optical subwavelength nanodevices. In our analysis, we compare and contrast the azimuthally symmetric modes, on which the previous literature has concentrated, with polaritonic guided modes, which propagate in a different regime close to the plasmonic resonance of the waveguide. Forward and backward modes may be envisioned in this latter regime, traveling with subdiffraction cross section along the cylindrical interface between plasmonic and nonplasmonic materials. In general, two oppositely oriented power flows arise in the positive and negative permittivity regions, consistent with our previous results in the planar geometry. Our discussion applies to a various range of frequencies, from RF to optical and UV, even if we are mainly focused on optical and infrared propagation. At lower frequencies, artificially engineered plasmonic metamaterials or natural plasmas may be envisioned to obtain similar propagation characteristics.
Effects of flow on solute exchange between fluids and supported biosurfaces
Authors: Hermens Wim Th. , Beneš Martin , Richter Ralf , Speijer Han
Published: November 2007

Uptake of nutrients by cultured cells on solid supports, conversion of substrates by surface‐bound catalysts and binding of antibodies to microtitre plates are examples of transport processes that are strongly influenced by the flow conditions in the surrounding fluid. The literature on this subject is scattered over widely different research fields and is often found in dated, and not generally available, treatises. Also, the subject is inherently complicated from a mathematical viewpoint, because even the simplest experimental configurations will usually not allow analytical solutions for the diffusion–convection equations describing the solute mass transport in the system. Fortunately, however, relatively simple expressions for the rates of mass transport can often be obtained in physically realistic limiting cases. The present study attempts to give a short overview of the main experimental models used in this field and presents simple equations for the estimation of solute exchange rates between surfaces and fluids. The models considered are: (1) uptake from an unstirred solution; (2) reversible binding from a perfectly stirred solution; (3) reversible binding through an unstirred fluid layer; (4) catalytic conversion at the internal surface of a tube or a slit with laminar flow; (5) adsorption by a surface opposite a rotating stirrer; (6) adsorption from an impinging fluid jet; and (7) uptake by the surface of a rotating disc. In practical situations the property of uniform accessibility proves to be of crucial importance. Stirring by ultrasound, more specifically the use of acoustic streaming in nano‐devices, is also discussed.
Generation of a tissue‐engineered tracheal equivalent
Authors: Kojima Koji , Vacanti Charles A.
Published: November 2007

In this Minireview we summarize efforts to generate an autologous tissue‐engineered trachea (TET) shaped as a cylinder containing a helix of cartilage to form the structural component of a functional tracheal replacement. Our first step was to demonstrate that a composite engineered tracheal equivalent composed of cartilaginous cylinder could be lined with nasal epithelial cells in a nude‐mouse model. We then demonstrated the feasibility of creating the cartilage and fibrous portion of the trachea using autologous tissue harvested from a single procedure in both nude‐rat and sheep models. Gross morphology and tissue morphology of these TET series were similar to that of native trachea. Histological data indicated the presence of mature cartilage formation of a pseudostratified columnar epithelium and the presence of mature cartilage surrounded by connective tissue, as would be expected of native trachea. Regarding the biomechanical properties, the cartilage was excellent in nude model; however, sheep autologous TET provided less support and therefore collapsed easily. In addition to utilizing the angiogenic qualities of cytokines, we hope to exploit the growth potentials of stromal cells derived from bone marrow for the production of a clinically practical, bioengineered trachea.
Uniformly oriented bacterial F0F1‐ATPase immobilized on a semi‐permeable membrane: a step towards biotechnological energy transduction
Authors: Bhattacharya Sumana , Schiavone Marc , Nayak Amiya , Bhattacharya Sanjoy K.
Published: November 2007

The immobilization of F0F1‐ATPase in uniform orientation is reported. The biotinylated and histidine‐tagged subunits of the bacterial F0F1‐ATPase complex were used for immobilization of the complex on artificial semi‐permeable membranes resulting in 88±7.8 and 72±5.2% coupling of the enzymes. The immobilized enzymes retained over 90% activity. The immobilized ATPase/synthase was used for generation of ATP from ADP and Pi at the expense of electrochemical potential energy. The re‐usability, ratio of amount of enzyme immobilized to enzymic activity conferred on the membranes, ATP synthesized by assembled system and suitability of ATP generated for use in coupled enzymic reactions were determined.
Mannan–penicillin G acylase neoglycoproteins and their potential applications in biotechnology
Authors: Masárová Jana , Mislovičová Danica , Mendichi Raniero , Švitel Juraj , Gemeiner Peter , Danielsson Bengt
Published: November 2007

Mannan–penicillin G acylase neoglycoproteins were prepared by the conjugation of Saccharomyces cerevisiae mannan with enzyme penicillin G acylase using the reductive amination method. Eight neoglycoproteins preparations were obtained after gel chromatography. The preparations contained from 42 to 67% (w/w) saccharides and their molar masses varied from 283 to over 1000 kDa. Significant biospecific interaction of separated fractions with the lectin concanavalin A was evaluated by the precipitation and sorption method (equilibrium constants) and further characterized using surface plasmon resonance to determine kinetic association and dissociation constants. KD was determined over the range 10−7 M. High‐molar‐mass preparations appeared to be more suitable for preparation of stable and active complexes with concanavalin A for prospective use as a penicillin G acylase biocatalyst in enzyme reactors. The enzyme stability of such complexes was significantly increased compared with the original neoglycoprotein. Lower‐molar‐mass preparations were more suitable for applications such as biocatalysts in bioanalytical devices.
Modified‐vaccinia‐virus‐ankara (MVA) priming and fowlpox‐virus booster elicit a stronger CD8+ T‐cell response in mice against an HIV‐1 epitope than does a DNA/poxvirus prime‐booster approach
Authors: Vázquez‐Blomquist Dania , Quintana Diógenes , Duarte Carlos A.
Published: November 2007

A prime‐boost strategy combining FWPV (fowlpox virus) and the MVA (modified vaccinia virus Ankara), both expressing HIV‐1 multi‐V3 epitope polypeptides, was compared with a DNA‐based Semliki Forest virus replicon/poxvirus approach for the induction of a CD8+ T‐cell response. Priming mice with recombinant MVA and boosting with recombinant FWPV, and not in the reverse order, increased the number of specific interferon‐γ‐secreting cells in relation to the homologous combinations. Moreover, the improvement of the CD8+ T‐cell response with this combination was remarkably higher than that obtained by priming with a DNA vector containing a Semliki Forest virus replicon expressing the multi‐epitope polypeptide and boosting either with recombinant MVA or FWPV. These results open a new and attractive alternative for vaccine preparation against HIV‐1 using different immunogens.
Concentration of prion protein from biological samples to increase the limits of detection by immunoassay
Authors: Davidowitz Eliot , Eljuga Lucy , Dover Katarzyna , Tian Jean , Grossman Abraham
Published: November 2007

An RNA‐ligand‐based adsorbent has been shown to concentrate prion protein (PrP) from solutions in a model system. The work presented here extends the utility of the RNA‐based adsorbent to brain homogenates of cow, sheep, mule deer (Odocoileus hemionus) and elk (Cervus elaphus). Brain homogenates were diluted either in buffer, representing specimens used in post‐mortem tests, or in serum, modelling specimens used in biological‐fluid‐based tests. The RNA adsorbent was effective in binding PrPC (cellular PrP,) and PrPres (proteinase K‐resistant PrP) from the brain homogenates of all the species tested in both model systems. The three antibodies against PrP used in the experiments identified PrP in immunoblot analysis after concentrating PrP from brain homogenates with the adsorbent, indicating the general applicability of this technology for improving the detection of PrP in immunoassays. Utilization of RNA adsorbent increased the level of detection of PrPres by immunoblot over several‐hundredfold. The results obtained suggest that this RNA adsorbent can be used to increase detection in current post‐mortem immunoassays and for the development of a blood‐based ante‐mortem test.
Continuous production of monoclonal antibody in a packed‐bed bioreactor
Authors: Golmakany Naghmeh , Rasaee Mohammad Javad , Furouzandeh Mehdi , Shojaosadati Seyed Abbas , Kashanian Soheila , Omidfar Kobra
Published: November 2007

In the present study the growth and MAb (monoclonal antibody) production of a mouse×mouse hybridoma cell producing anti‐digoxin MAb was evaluated. The hybridoma cells entrapped within the support matrix Fibra‐Cel® were cultured in batch and continuous mode following special protocols. Cell‐culture studies were performed in a 1‐litre spinner basket containing 3 g·litre−1 support matrix. Batch culture was operated with the cell density of 42×106 cells. During the 7 days of culture, the medium was sampled daily in order to assess glucose and MAb concentrations and the lactate dehydrogenase released into the culture medium. After a culture period of 72 h, the cell density and MAb concentration were found to be 10.4×107 cells/3 g of NWPF (non‐woven polyester fibre) discs and 250 μg/ml respectively. This yield gradually decreased to 0.55×106 cells/3 g of packaging material and 60 μg/ml respectively at the end of the batch culture. In the continuous‐culture studies, the batch culture was initially operated for 64.5 h and then continuous flow was started at the dilution rates of 0.15, 0.2, 0.25 and 0.3 day−1 and finally stabilized at 0.25 day−1 within 288 h (12 days). The MAb concentration at steady state was found to be 116–120 μg/day per ml, and the yield of operation was 62.5 mg/day per ml, which was 3.5 times higher than that of batch culture. In conclusion, a packed‐bed bioreactor with the support matrix Fibra‐Cel®, operated in continuous‐feeding mode, is more efficient for large‐scale MAb production than a batch culture. On the other hand, by using a continuous‐culture system, a better supply of nutrients and removal of inhibitory metabolites and proteolytic enzymes was obtained.
Cloning, expression and characterization of a sialidase gene from Arthrobacter ureafaciens
Authors: Christensen Søren , Egebjerg Jan
Published: November 2007

Sialidases have recently been used in the processing of clinically relevant asialoproteins. The Arthrobacter ureafaciens sialidase (EC 3.2.1.18) exhibits broad substrate specificity and is often used in such applications. We have employed an expression cloning strategy to isolate the A. ureafaciens sialidase. The clone encodes a 990‐amino‐acid 104 kDa open‐reading‐frame protein containing three domains: an N‐terminal catalytic domain, a linker domain with an immunoglobulin‐like fold and a C‐terminal domain of unknown function. Expression in Escherichia coli indicates that the sialidase promoter was active in E. coli. Overexpression in E. coli resulted in several truncated forms. A 54 kDa truncated variant was generated, expressed and purified, and its feasibility for use in an erythropoietin desialylation process was demonstrated.
Breakthrough performance of large proteins on ion‐exchange membrane columns
Authors: Montesinos‐Cisneros Rosa Maria , Lucero‐Acuña Armando , Ortega Jaime , Guzmán Roberto , Tejeda‐Mansir Armando
Published: November 2007

Protein adsorption of large proteins on ion‐exchange membrane columns was theoretically and experimentally investigated using batch and fixed‐bed systems. Thyroglobulin was used as the model protein. The study strongly suggests that part of the protein is physically retained inside the column during frontal mode operation. These experimental results were used to obtain a filtration function of the chromatographic system. In the theoretical analysis of the frontal protein adsorption, a model was integrated by the serial coupling of the membrane‐transport model, the filtration model and the system‐dispersion model. Two different techniques were employed in the estimation of the maximum adsorption capacity, the equilibrium desorption constant and the forward interaction rate constant, which are the parameters of the membrane‐transport model. The fit of the model to the experimental data was not possible using the equilibrium parameters obtained in the batch experiments. The parameter estimation using a simplex optimization routine coupled to the solution of the partial differential model equations yields full prediction of the adsorption phenomena.
Expression of human coagulation Factor IX in transgenic tomato (Lycopersicon esculentum)
Authors: Zhang Hui , Zhao Lingxia , Chen Yuhui , Cui Lijie , Ren Weiwei , Tang Kexuan
Published: November 2007

In the present study, a plant binary expression vector PG‐pRD12‐hFIX (where PG is polygalacturonase) harbouring the hFIX (human coagulation Factor IX) gene was constructed and introduced into tomato (Lycopersicon esculentum) via Agrobacterium tumefaciens‐mediated transformation. After kanamycin selection, 32 putative independent transgenic tomato plants were regenerated. PCR and Southern‐blot analyses confirmed the transgenic status of some plants. RT (reverse transcription)–PCR analysis for the expression of the introduced gene (hFIX) demonstrated that the hFIX gene was expressed specifically in fruits of the tomato. Western‐blot analysis confirmed the presence of a 56 kDa band specific to hFIX in the transformed tomatoes. ELISA results showed that the expression of hFIX protein reached a maximum of 15.84 ng/g fresh weight in mature fruit. A blood‐clotting assay demonstrated the clotting activity of the expressed hFIX protein in transgenic tomato fruits. This is the first report on the expression of hFIX in plants, and our research provides potentially valuable knowledge for further development of the plant‐derived therapeutic proteins.
Characterization of a human telomerase reverse transcriptase sequence containing two antigenic epitopes with high affinity for human leucocyte antigen
Authors: Wang Jinwen , Yu Liang , Li Jianfeng , Deng Riqiang , Wang Xunzhang
Published: November 2007

Almost all human malignant tumours exhibit strong telomerase activity, but normal adult tissues, with a few exceptions, do not. hTERT (human telomerase reverse transcriptase) is an essential component of telomerase, and hence it can serve as a parallel sign in the diagnosis and prognosis of cancers. In the present study, we selected a sequence of hTERT containing two antigenic epitopes that have high affinity for HLA‐A2 (human leucocyte antigen‐A2) as a TAA (tumour‐associated antigen) based on a peptide–motif scoring system. The sequence was obtained by reverse‐transcriptase PCR and cloned into the Escherichia coli expression vector pGEX‐4T‐1. The expression product appeared in the form of inclusion bodies. Denatured inclusion‐body extract was subjected to SDS/PAGE, and the gel band corresponding to the putative 38 kDa fusion protein (GST–hTERT major tumour‐associated antigen) was excised, ground with PBS, mixed with Freund's adjuvant and used to inoculate mice, generating anti‐TERT polyclonal antibodies. Western blotting using the leukaemia cell line THP‐1 demonstrated that the antibodies were able to detect hTERT expression, implying the potential applicability of the antigenic peptides derived from hTERT as a universal marker in the diagnosis and prognosis of tumours.
A prototype software methodology for the rapid evaluation of biomanufacturing process options
Authors: Chhatre Sunil , Francis Richard , O'Donovan Kieran , Titchener‐Hooker Nigel J. , Newcombe Anthony R. , Keshavarz‐Moore Eli
Published: November 2007

A three‐layered simulation methodology is described that rapidly evaluates biomanufacturing process options. In each layer, inferior options are screened out, while more promising candidates are evaluated further in the subsequent, more refined layer, which uses more rigorous models that require more data from time‐consuming experimentation. Screening ensures laboratory studies are focused only on options showing the greatest potential. To simplify the screening, outputs of production level, cost and time are combined into a single value using multi‐attribute‐decision‐making techniques. The methodology was illustrated by evaluating alternatives to an FDA (U.S. Food and Drug Administration)‐approved process manufacturing rattlesnake antivenom. Currently, antivenom antibodies are recovered from ovine serum by precipitation/centrifugation and proteolysed before chromatographic purification. Alternatives included increasing the feed volume, replacing centrifugation with microfiltration and replacing precipitation/centrifugation with a Protein G column. The best alternative used a higher feed volume and a Protein G step. By rapidly evaluating the attractiveness of options, the methodology facilitates efficient and cost‐effective process development.
Effects of low-dose ketanserin on blood pressure variability, baroreflex sensitivity and end-organ damage in spontaneously hypertensive rats
Authors: XIE He-Hui , SHEN Fu-Ming , CAO Yong-Bing , LI Hui-Lin , SU Ding-Feng
Published: November 2007

The present study was designed to investigate the effects of low-dose ketanserin on BPV (blood pressure variability), BRS (baroreflex sensitivity) and organ damage in SHR (spontaneously hypertensive rats). Ketanserin was mixed in rat chow at an estimated dose of 0.1 mg·kg−1 of body weight·day−1. SHR were treated for 4 months. BP (blood pressure) was then recorded continuously for 24 h in a conscious state. After determination of BRS, rats were killed for organ damage evaluation. It was found that long-term treatment with low-dose ketanserin did not lower BP levels, but significantly decreased BPV, enhanced BRS and reduced organ damage in SHR. Multiple regression analysis showed that the decrease in left ventricular hypertrophy was most closely correlated (or associated) with the increase in BRS, whereas the decrease in aortic hypertrophy was most closely associated with the decrease in diastolic BPV and the amelioration in renal lesion, with the increase in BRS and the decrease in diastolic BPV. In conclusion, low-dose ketanserin produces organ protection independently of its BP-lowering action in SHR, and this organ protection was importantly attributable to the enhancement of BRS and decrease in BPV.
Oxidative stress and high-density lipoprotein function in Type I diabetes and end-stage renal disease
Authors: KALOGERAKIS George , BAKER Arthur M. , CHRISTOV Steve , ROWLEY Kevin G. , DWYER Karen , WINTERBOURN Christine , BEST James D. , JENKINS Alicia J.
Published: November 2007

In a cross-sectional study, oxidative stress in high vascular disease risk groups, ESRD (end-stage renal disease) and Type I diabetes, was assessed by measuring plasma protein carbonyls and comparing antioxidant capacity of HDL (high-density lipoprotein) as pertaining to PON1 (paraoxonase 1) activity and in vitro removal of LPO (lipid peroxides). ESRD subjects on haemodialysis (n=22), Type I diabetes subjects (n=20) without vascular complications and healthy subjects (n=23) were compared. Plasma protein carbonyls were higher in ESRD patients [0.16 (0.050) nmol/mg of protein; P=0.001; value is mean (SD)] relative to subjects with Type I diabetes [0.099 (0.014) nmol/mg of protein] and healthy subjects [0.093 (0.014) nmol/mg of protein]. Plasma PON1 activity, with and without correction for HDL-cholesterol, was lower in diabetes but did not differ in ESRD compared with healthy subjects. Plasma PON1 activity, without correction for HDL, did not differ between the three groups. In ESRD, plasma PON1 activity and plasma protein carbonyl concentrations were inversely related (r=−0.50, P<0.05). In an in vitro assay, LPO removal by HDL in ESRD subjects was greater than HDL from healthy subjects (P<0.01), whereas HDL from patients with Type I diabetes was less effective (P<0.01). Efficacy of LPO removal was unrelated to plasma PON1 activity, in vitro glycation or mild oxidation, but was impaired by marked oxidation and glycoxidation. Protein carbonyl levels are increased in ESRD but not in complication-free Type I diabetes. HDL antioxidant function is increased in ESRD, perhaps a compensatory response to increased oxidative stress, but is lower in Type I diabetes. HDL dysfunction is related to glycoxidation rather than glycation or PON1 activity.
Genetic variation in the rate-limiting enzyme in cholesterol catabolism (cholesterol 7α-hydroxylase) influences the progression of atherosclerosis and risk of new clinical events
Authors: HOFMAN Maaike K. , PRINCEN Hans M. G. , ZWINDERMAN Aeilko H. , JUKEMA J. Wouter
Published: November 2007

CHD (coronary heart disease) is a complex disorder which is, in part, related to serum cholesterol levels. The rate-limiting enzyme in the catabolism of cholesterol into bile acids is CYP7A1 (cholesterol 7α-hydroxylase). The effect of the CYP7A1 A−278C promoter polymorphism on the progression of atherosclerosis, risk of a new clinical event and the influence of this variant on cholesterol-lowering therapy was investigated in 715 male patients with coronary atherosclerosis participating in REGRESS (Regression Growth Evaluation Statin Study). Genotype distributions were as follows: 283 with AA; 330 with AC and 102 with CC. There were no significant differences in baseline characteristics and serum lipids between genotypes. After 2 years, CC carriers had more progression of diffuse and focal atherosclerosis compared with AA carriers, as indicated by a larger decrease in MSD (mean segment diameter; 0.09 mm compared with 0.06 mm respectively; P=0.009) and MOD (minimum obstruction diameter; 0.09 mm compared with 0.05 mm respectively; P=0.024). Inclusion of risk factors for CHD in the model showed the same trend, although not significant for MOD (P=0.01 for MSD, and P=0.06 for MOD). In addition, CC carriers had an almost 2-fold higher risk of a new clinical event compared with AA carriers [RR (95% CI) 1.93 (1.11–3.36); P=0.02; where RR is relative risk and CI is confidence interval]. Inclusion of risk factors for CHD in the model showed the same trend, although not significant [RR (95% CI), 1.74 (0.96–3.12); P=0.06]. In conclusion, we present evidence that the CC variant of the A−278C polymorphism in the rate-limiting enzyme in the catabolism of cholesterol, CYP7A1, increases the progression of atherosclerosis and possibly the risk of a new clinical event.
Structural changes in the airways in asthma: observations and consequences
Authors: BAI Tony R. , KNIGHT Darryl A.
Published: November 2007

Structural changes reported in the airways of asthmatics include epithelial fragility, goblet cell hyperplasia, enlarged submucosal mucus glands, angiogenesis, increased matrix deposition in the airway wall, increased airway smooth muscle mass, wall thickening and abnormalities in elastin. Genetic influences, as well as fetal and early life exposures, may contribute to structural changes such as subepithelial fibrosis from an early age. Other structural alterations are related to duration of disease and/or long-term uncontrolled inflammation. The increase in smooth muscle mass in both large and small airways probably occurs via multiple mechanisms, and there are probably changes in the phenotype of smooth muscle cells, some showing enhanced synthetic capacity, others enhanced proliferation or contractility. Fixed airflow limitation is probably due to remodelling, whereas the importance of structural changes to the phenomenon of airways hyperresponsiveness may be dependent on the specific clinical phenotype of asthma evaluated. Reduced compliance of the airway wall secondary to enhanced matrix deposition may protect against airway narrowing. Conversely, in severe asthma, disruption of alveolar attachments and adventitial thickening may augment airway narrowing. The encroachment upon luminal area by submucosal thickening may be disadvantageous by increasing the risk of airway closure in the presence of the intraluminal cellular and mucus exudate associated with asthma exacerbations. Structural changes may increase airway narrowing by alteration of smooth muscle dynamics through limitation of the ability of the smooth muscle to periodically lengthen.
Angiotensin II modulates frizzled-2 receptor expression in rat vascular smooth muscle cells
Authors: CASTOLDI Giovanna , REDAELLI Serena , van de GREEF Willy M. M. , di GIOIA Cira R. T. , BUSCA Giuseppe , SPERTI Giovanni , STELLA Andrea
Published: November 2007

Ang II (angiotensin II) has multiple effects on vascular smooth muscle cells through the modulation of different classes of genes. Using the mRNA differential-display method to investigate gene expression in rat aortic smooth muscle cells in culture in response to 3 h of Ang II stimulation, we observed that Ang II down-regulated the expression of a member of the family of transmembrane receptors for Wnt proteins that was identified as Fzd2 [Fzd (frizzled)-2 receptor]. Fzds are a class of highly conserved genes playing a fundamental role in the developmental processes. In vitro, time course experiments demonstrated that Ang II induced a significant increase (P<0.05) in Fzd2 expression after 30 min, whereas it caused a significant decrease (P<0.05) in Fzd2 expression at 3 h. A similar rapid up-regulation after Ang II stimulation for 30 min was evident for TGFβ1 (transforming growth factor β1; P<0.05). To investigate whether Ang II also modulated Fzd2 expression in vivo, exogenous Ang II was administered to Sprague–Dawley rats (200 ng·kg−1 of body weight·min−1; subcutaneously) for 1 and 4 weeks. Control rats received normal saline. After treatment, systolic blood pressure was significantly higher (P<0.01), whereas plasma renin activity was suppressed (P<0.01) in Ang II- compared with the saline-treated rats. Ang II administration for 1 week did not modify Fzd2 expression in aorta of Ang II-treated rats, whereas Ang II administration for 4 weeks increased Fzd2 mRNA expression (P<0.05) in the tunica media of the aorta, resulting in a positive immunostaining for fibronectin at this time point. In conclusion, our data demonstrate that Ang II modulates Fzd2 expression in aortic smooth muscle cells both in vitro and in vivo.
Eicosanoids: mediators and therapeutic targets in fibrotic lung disease
Authors: CHARBENEAU Ryan P. , PETERS-GOLDEN Marc
Published: November 2007

Fibrosis is a common end-stage sequella of a number of acute and chronic lung diseases. Current concepts of pathogenesis implicate dysregulated interactions between epithelial cells and mesenchymal cells. Although investigative efforts have documented important roles for cytokines and growth factors in the pathogenesis of fibrotic lung diseases, these observations have not as yet been translated into efficacious therapies, and there is a pressing need for new pathogenetic insights and therapeutic approaches for these devastating disorders. Eicosanoids are lipid mediators derived from arachidonic acid, the most studied of which are the prostaglandins and leukotrienes. Although they are primarily known for their roles in asthma, pain, fever and vascular responses, present evidence indicates that eicosanoids exert relevant effects on immune/inflammatory, as well as structural, cells pertinent to fibrogenesis. In general, leukotrienes promote, whereas prostaglandin E2 opposes, fibrogenic responses. An imbalance of eicosanoids also exists in pulmonary fibrosis, which favours the production of leukotrienes over prostaglandin E2. This review highlights the role of this imbalance in the evolution of fibrotic lung disease, discusses the mechanisms by which it may arise and considers approaches for therapeutic targeting of eicosanoids in these conditions.
C-reactive protein and statins: IL-8 as a molecular link?
Authors: SZMITKO Paul E. , VERMA Subodh
Published: November 2007

CRP (C-reactive protein) has not only emerged as a useful biomarker for cardiovascular disease, but also as a mediator of atherosclerosis. CRP directly activates vascular endothelial cells, amplifying the inflammatory response underlying atherogenesis. The expression of IL (interleukin)-8 appears to serve as one of the downstream effects of CRP. Kibayashi and co-workers in this issue of Clinical Science confirm that CRP induces IL-8 production in human aortic endothelial cells in vitro, via the activation of MAPKs (mitogen-activated protein kinases), an effect that can be inhibited by pitavastatin.
Adiponectin: a key adipocytokine in metabolic syndrome
Authors: Okamoto Yoshihisa , Kihara Shinji , Funahashi Tohru , Matsuzawa Yuji , Libby Peter
Published: November 2007

The metabolic syndrome, a cluster of metabolic disorders often associated with visceral obesity, increases cardiovascular mortality and morbidity. As the body's largest endocrine organ, adipose tissue not only stores excess body energy, but also secretes a variety of bioactive adipocytokines. Obese patients, particularly those with visceral fat accumulation, have reduced plasma levels of adiponectin, the most abundant and adipose-specific adipocytokine. Although the association of adiponectin with several diseases remains controversial, many clinical studies have demonstrated that low plasma concentrations of adiponectin (hypoadiponectinaemia) associate closely with obesity-related diseases, including atherosclerotic cardiovascular diseases, Type II diabetes mellitus, hypertension and dyslipidaemia. Accumulating experimental evidence indicates that adiponectin possesses anti-atherogenic, anti-inflammatory and anti-diabetic properties and may also participate importantly in the mechanism of metabolic syndrome and other diseases. Despite these associations, further clinical and experimental investigations will be needed to illuminate the in vivo pathophysiological significance of this protein. Although evaluation of adiponectin as a novel therapy will ultimately require clinical intervention studies, this mediator may represent a novel target for the prevention and treatment of visceral obesity metabolic syndrome.
Molecular genetics of human hypertension
Authors: Gong Maolian , Hubner Norbert
Published: November 2007

EH (essential hypertension) is a major public health problem in many countries due to its high prevalence and its association with coronary heart disease, stroke, renal disease, peripheral vascular disease and other disorders. Epidemiological studies have demonstrated that EH is heritable. Owing to the fact that blood pressure is controlled by cardiac output and total peripheral resistance, many molecular pathways are believed to be involved in the disease. In this review, recent genetic studies investigating the molecular basis of EH, including different molecular pathways, will be highlighted.
Vascular and fibrinolytic effects of intra-arterial tumour necrosis factor-α in patients with coronary heart disease
Authors: Robinson Simon D. , Dawson Pamela , Ludlam Christopher A. , Boon Nicholas A. , Newby David E.
Published: November 2007

Elevated plasma t-PA (tissue plasminogen activator) and serum CRP (C-reactive protein) concentrations are associated with an adverse cardiovascular risk. In the present study, we investigated whether acute local inflammation causes vascular dysfunction and influences t-PA release in patients with stable coronary heart disease. Serum CRP, plasma t-PA and PAI-1 (plasminogen activator inhibitor type 1) concentrations were determined in 95 patients with stable coronary heart disease. A representative subpopulation of 12 male patients received an intra-brachial infusion of TNF-α (tumour necrosis factor-α) and saline placebo using a randomized double-blind cross-over study design. Forearm blood flow and plasma fibrinolytic and inflammatory variables were measured. Serum CRP concentrations correlated with plasma t-PA concentrations (r=0.37, P<0.001) and t-PA/PAI-1 ratio (r=−0.21, P<0.05). Intra-arterial TNF-α caused a rise in t-PA concentrations (P<0.001) without affecting blood flow or PAI-1 concentrations. TNF-α pretreatment impaired acetylcholine- and sodium nitroprusside-induced vasodilatation (P<0.001 for both) whilst doubling bradykinin-induced t-PA release (P=0.006). In patients with stable coronary heart disease, plasma fibrinolytic factors correlate with a systemic inflammatory marker and local vascular inflammation directly impairs vasomotor function whilst enhancing endothelial t-PA release. We suggest that the adverse prognosis associated with elevated plasma t-PA concentrations relates to the underlying causative association with vascular inflammation and injury.