bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between Leptin Concentration in Cord Blood and Foetal Growth and Maternal Anthropometry of GDM Mothers at Delivery
Authors: Jahan S , Das TR , Biswas KB
Published: August 2007

Background and Aims: Cord blood leptin may reflect the leptinemic status of a newborn at birth more accurately than the leptin values of blood collected from other sites. The present study was undertaken to determine the relationship of cord serum leptin concentration at birth with neonatal and maternal anthropometric parameters.

Materials and Methods: Blood was taken from the umbilical cord of the babies at delivery. Maternal anthropometric measurements were recorded at admission for delivery. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between cord serum leptin concentration and anthropometric parameters of the baby and the mother. Both Serum leptin and serum C-peptide levels were measured by chemiluminescence-based ELISA method.

Results: The leptin concentration (ng/ml, mean±SD) in cord blood was 39.13±14.44. Cord leptin levels correlated with birth weight (r=0.673, p<0.0001), ponderal index (r=0.732, p<0.0001) but it did not correlate with maternal body mass index, gestational age (r=0.135, p=0.349) at delivery or cord serum C-peptide concentration (r=-0.049, p=0.735) or placental weight (r=0.203, p=0.157).

Conclusion: There are associations between cord leptin concentration at delivery and birth weight, ponderal index (PI) of the babies but not body mass index (BMI) of the mothers. High leptin levels of the baby could represent an important feedback modulator of substrate supply and subsequently for adipose tissue status during late gestation.

(J Bangladesh Coll Phys Surg 2007; 25 : 9-13)
Primary Male Breast Cancer: Analysis of Eight Cases and Review of Literature
Authors: Ahmed JU , Hussain MM
Published: August 2007

This is a hospital based retrospective study with 8 cases of newly diagnosed primary male breast cancer. Among 413 cases of breast cancer of both male and females, treated between 1988 to 2002 at Chittagong, eight were males. The incidence is 1.94%. The mean age of diagnosis is 50.13 years, which is later than females. A breast mass was the earliest, most important symptom. The duration of symptoms before treatment ranged from few weeks to years. Male breast cancer is of the same common pathologic types as in females that is 75% patients had duct cell carcinoma. The rarity of the tumor hinders the study of its biological behavior and etiology, which in consequence, are still not well understood. As with the female breast cancer, surgical excision followed by adjuvant CT, RT, hormone therapy are the treatment modalities.

(J Bangladesh Coll Phys Surg 2007; 25 : 18-22)
Measuring low back injury risk factors in challenging work environments: An evaluation of cost and feasibility
Authors: Trask Catherine , Teschke Kay , Village Judy , Chow Yat , Johnson Peter , Luong Nancy , Koehoorn Mieke
Published: August 2007

Background

Measuring low back injury risk factors in field research presents challenges not encountered in laboratory environments.

Methods

We compared the practical application of five measurement methods (observations, interviews, electromyography (EMG), inclinometry, and vibration monitoring) for 223 worker days in 50 heavy‐industry worksites in western Canada. Data collection successes, challenges, costs, and data detail were documented for each method.

Results

Measurement success rates varied from 42.2% (seatpan accelerometer) to 99.6% (post‐shift interview) of worker days assessed. Missed days for direct monitoring equipment were primarily due to explosive environments, workplace conditions likely to damage the equipment, and malfunctions. Costs per successful measurement day were lowest for interviews (∼$23), about 10‐fold higher for observations and inclinometry, and more than 20‐fold higher for EMG and vibration monitoring.

Conclusions

Costs and successful field performance need to be weighed against the added data detail gained from monitoring equipment when making choices about exposure assessment techniques for epidemiological studies. Am. J. Ind. Med. 50:687–696, 2007. © 2007 Wiley‐Liss, Inc.
Aspect ratio effect on oxygen transfer process in rectangular tank surface aerator
Authors: Ramakrishna Rao Achanta , Kumar Bimlesh
Published: August 2007

Surface aeration experiments were conducted in three types of geometrically similar rectangular tanks of aspect ratios, i.e. length to width ratio (L/W) of 1, 1.5 and 2 in order to study the effect of aspect ratio on the oxygen transfer process. It is observed that for geometrically similar tanks, oxygen transfer coefficient (KLa20) is uniquely related to the mean velocity gradient (G). It has been found that at constant mean velocity gradient (G),KLa20is high in lower aspect ratio tanks and it decreases as the aspect ratio increases. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Effect of reaction temperature on conversion and thermal properties of polyamide hot‐melt adhesives
Authors: Ghasem N. M. , Heiderian J. , Daud W. W.
Published: August 2007

The work described in this paper aims at exploring the effect of reaction temperature, with and without a catalyst on the conversion and thermal properties of polyamide hot‐melt adhesives. The polyamides were synthesized from C36 dimer acid and ethylenediamine; o‐phosphoric acid was used as catalyst. The thermal properties investigated were glass transition temperature, melting point, heat of fusion, and molecular weight of the final products. Glass transition temperatures, heat of fusion, and melting point were found to increase with increasing molecular weight. Glass transition temperature was found to be in the range of 62–66 °C; however, for noncatalytic reaction at 130 °C, the final product was in liquid phase at room temperature and no glass transition temperature was detected. Results show that as the polymerization reaction temperature increases, the number average molecular weight increases. In the reaction, ethylenediamine and dimer acid should be taken in equivalent amounts to produce polyamides with high and desirable molecular weights. Excess of ethylenediamine will lead to low molecular weight products with the free amine group left unreacted. However, an extra amount of the ethylenediamine should be added initially to compensate for the evaporated loss of ethylene diamines. The excess amount should be equivalent to the amount that would evaporate during the preheating process. Parameters of the rate equations and the empirical parameters were determined with nonlinear regression analysis. The kinetic model was used to simulate experiments that were not included in the empirical parameter estimation. The comparison of the model predictions with the experimental data showed good agreement. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Peptide surfactants (Pepfactants) for switchable foams and emulsions
Authors: Malcolm Andrew S. , Dexter Annette F. , Middelberg Anton P. J.
Published: August 2007

We have developed a series of sustainable peptide surfactants (Pepfactants) capable of stabilizing foams and emulsions in a stimuli‐responsive manner, based on the reversible formation of a mechanically strong interfacial film. Under conditions where the interfacially adsorbed peptide forms a mechanically strong ‘film state’, foam or emulsion stabilization occurs as a direct result of the film strength. Under conditions where the interfacially adsorbed peptide forms a mobile ‘detergent state’, foam or emulsion stabilization is either reduced, or does not occur. Preformed foams or emulsions stabilized by Pepfactants undergo rapid phase coalescence when the film state is converted to the detergent state. Switching between film and detergent states is readily and reversibly achieved by a change in the bulk solution composition, such as a change in pH, or the addition or sequestering of metal ions. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Dense‐core and diffuse Aβ plaques in TgCRND8 mice studied with synchrotron FTIR microspectroscopy
Authors: Rak Margaret , Del Bigio Marc R. , Mai Sabine , Westaway David , Gough Kathleen
Published: August 2007

Plaques composed of the Aβ peptide are the main pathological feature of Alzheimer's disease. Dense‐core plaques are fibrillar deposits of Aβ, showing all the classical properties of amyloid including β‐sheet secondary structure, while diffuse plaques are amorphous deposits. We studied both plaque types, using synchrotron infrared (IR) microspectroscopy, a technique that allows the chemical composition and average protein secondary structure to be investigated in situ. We examined plaques in hippocampal, cortical and caudal tissue from 5‐ to 21‐month‐old TgCRND8 mice, a transgenic model expressing doubly mutant amyloid precursor protein, and displaying impaired hippocampal function and robust pathology from an early age. Spectral analysis confirmed that the congophilic plaque cores were composed of protein in a β‐sheet conformation. The amide I maximum of plaque cores was at 1623 cm−1, and unlike for in vitro Aβ fibrils, the high‐frequency (1680–1690 cm−1) component attributed to antiparallel β‐sheet was not observed. A significant elevation in phospholipids was found around dense‐core plaques in TgCRND8 mice ranging in age from 5 to 21 months. In contrast, diffuse plaques were not associated with IR detectable changes in protein secondary structure or relative concentrations of any other tissue components. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 207–217, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Toward a framework for sulfoproteomics: Synthesis and characterization of sulfotyrosine‐containing peptides
Authors: Seibert Christoph , Sakmar Thomas P.
Published: August 2007

Tyrosine sulfation is one of the most common post‐translational modifications in secreted and transmembrane proteins and a key modulator of extracellular protein‐protein interactions. Several proteins known to be tyrosine sulfated play important roles in physiological processes, and in some cases a direct link between protein function and tyrosine sulfation has been established. In blood coagulation, tyrosine sulfation of factor VIII is required for efficient binding of von Willebrand factor; in leukocyte adhesion, tyrosine sulfation of the P‐selectin glycoprotein ligand‐1 mediates high‐affinity binding to P‐selectin; and in leukocyte chemotaxis, tyrosine sulfation of chemokine receptors is required for optimal interaction with chemokine ligands. Furthermore, tyrosine sulfation has been implicated in several infectious diseases. In particular, tyrosine sulfation of the HIV‐1 co‐receptor CCR5 is required for viral entry into host cells and tyrosine sulfation of the Duffy antigen/receptor for chemokines is crucial for erythrocyte invasion by the malaria parasite plasmodium vivax. Despite increasing interest in tyrosine sulfation in recent years, the sulfoproteome still remains largely unexplored. To date, only a relatively small number of sulfotyrosine‐containing peptides and proteins have been identified, and a specific role for tyrosine sulfation has not been established for most of these. Here, we provide an overview of the biology and enzymology of tyrosine sulfation and discuss recent developments in preparative and analytical methods that are central to sulfoproteome research. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 459–477, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprintversion. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley. com
Evidence of species succession during chlorobenzene biodegradation
Authors: Baptista I.I.R. , Zhou N.Y. , Emanuelsson E.A.C. , Peeva L.G. , Leak D.J. , Mantalaris A. , Livingston A.G.
Published: August 2007

We have previously reported the disappearance of a specific strain degrading chlorobenzene from a functionally stable bioreactor. In the present work, we investigated this species succession and isolated a new dominant strain, identified as Pandoraea pnomenusa sp. strain MCB032. A specific 16S rRNA‐targeted oligonucleotide probe was designed and validated to identify strain MCB032 using fluorescence in situ hybridisation (FISH). The results confirmed the presence of strain MCB032 in samples collected over time, and showed that it was primarily located within the biofilm. Denaturing gradient gel electrophoresis (DGGE) provided evidence that the species succession occurred early in the operating period. The application of these biomolecular tools highlighted the remarkable stability of this new strain during the 15 months of reactor operation. The succession was attributed to the competitive kinetic behaviour of strain MCB032, which exhibited faster growth (µmax = 0.34 h−1) and higher substrate affinity (Ks = 0.35 mg L−1) than strain JS150. Finally, this study contributed to the characterisation of the recently established Pandoraea genus, an emerging group in the biodegradation field. Biotechnol. Bioeng. 2008;99: 68–74. © 2007 Wiley Periodicals, Inc.
A semicontinuous 3‐column countercurrent solvent gradient purification (MCSGP) process
Authors: Aumann Lars , Morbidelli Massimo
Published: August 2007

The recently developed continuous Multicolumn Countercurrent Solvent Gradient Purification (MCSGP) Process has been reduced to a fully equivalent semicontinuous setup with only three chromatographic columns and three gradient pump modules. Actually the 3‐column MCSGP unit can even achieve better performance than the original 6‐column process due to an additional degree of freedom, that is a different switching time for the “batch lane” and the “interconnected lane.” Experimental results for the 3‐column MCSGP unit of the purification of an industrial multicomponent peptide mixture containing 46% of Calcitonin on a reversed phase resin are compared with model simulations. It is concluded, that the model is well suited to predict the system behavior and therefore to design its optimal operating conditions. Biotechnol. Bioeng. 2008;99: 728–733. © 2007 Wiley Periodicals, Inc.
A study of the influence of yeast cell debris on protein and α‐glucosidase adsorption at various zones within the expanded bed using In‐Bed sampling
Authors: Balasundaram B. , Harrison S.T.L. , Li J. , Chase H.A.
Published: August 2007

Expanded bed adsorption chromatography is used to capture products directly from unclarified feedstocks, thus combining solid–liquid separation, product concentration and preliminary purification into a single step. However, when non‐specific ion‐exchangers are used as the adsorbent in the expanded bed, there is the possibility that electrostatic interactions of cells or cell debris with the adsorbent may interfere with the adsorption of soluble products. These interactions depend on the particle size of the cell debris and its surface charge, which in turn depend on the extent of disruption used to release the intracellular products. The interactions occurring during expanded bed adsorption between the anionic ion‐exchanger STREAMLINE DEAE and particulate yeast homogenates obtained by high pressure homogenisation at different intensities of disruption achieved by operating at different pressures were studied, while maintaining all other parameters constant. In‐bed sampling from the expanded bed using ports fitted up the height of expanded bed was used to study the retention of yeast cells and cell debris within the bed and its influence on the adsorption of total soluble protein and α‐glucosidase within various zones of the expanded bed. The retention of the biomass present in the homogenate obtained at a lower intensity of disruption was found to be high at the lower end of the column (17% from 13.8 MPa sample compared to 1% from 41.4 MPa sample). This interaction of the particulate material with the adsorbent was found to reduce the dynamic binding capacity of the adsorbent for total soluble protein from 3.6 mg/mL adsorbent for 41.4 MPa sample to 3.0 mg/mL adsorbent for 13.8 MPa sample. The adsorption of α‐glucosidase was found to increase with an increase in the concentration of the enzyme in the feed, which increased with the intensity of disruption. Selective adsorption of 6,732 U α‐glucosidase per mg of total protein bound, was noticed for the feedstock prepared at a higher disruption intensity at 41.4 MPa compared to adsorption of 1,262 U/mg of total protein bound for that prepared at 13.8 MPa. The selective adsorption of α‐glucosidase due to its high concentration together with simultaneous high specific activity of the enzyme in the feed indicated the significance of selective release of enzymes during microbial cell disruption for efficient expanded bed adsorption processes. Biotechnol. Bioeng. 2008;99: 614–624. © 2007 Wiley Periodicals, Inc.
Detection of chrysotile asbestos by using a chrysotile‐binding protein
Authors: Kuroda Akio , Nishimura Tomoki , Ishida Takenori , Hirota Ryuichi , Nomura Kazutaka
Published: August 2007

In the current studies, we found that the DksA protein from Escherichia coli binds strongly to chrysotile, which is the most commonly used form of asbestos. We developed a convenient colorimetric assay for chrysotile using a fusion of DksA and alkaline phosphatase along with 5‐bromo‐4‐chloro‐3‐indolyl‐phosphate and nitro blue tetrazolium as substrates. Also, using a fusion of DksA and green‐fluorescent protein, we were able to detect chrysotile by fluorescence microscopy. Biotechnol. Bioeng. 2008;99: 285–289. © 2007 Wiley Periodicals, Inc.
Production and separation of manganese peroxidase from heme amended yeast cultures
Authors: Jiang Fei , Kongsaeree Puapong , Charron Rose , Lajoie Curtis , Xu Haowen , Scott Gary , Kelly Christine
Published: August 2007

A method for the production and concentration of the lignin‐degrading enzyme, manganese peroxidase (rMnP), was developed using the yeast Pichia pastoris in high cell density, fed‐batch cultivations. A gene encoding manganese peroxidase (mnp1) from the white‐rot fungus Phanerochaete chrysosporium was cloned into a protease deficient (pep4−) strain of the methylotrophic yeast P. pastoris. Heme is an important cofactor for active rMnP production, and amendment of yeast cultures with heme increased active rMnP concentrations. In both shake‐flasks and fed‐batch bioreactors, the relationship between heme concentration and rMnP activity was logarithmic, with increasing heme concentrations resulting in progressively lesser increases in enzyme activity. Scale‐up from shake‐flasks to 2 L fed‐batch cultivations increased rMnP activities from 200 U/L to 2,500 U/L, with addition of 0.1 g/L heme (added heme per liquid volume) at the beginning of the fed‐batch phase resulting in higher enzyme activities than addition at the beginning of the batch phase. A combination of centrifugation, acetone precipitation, dialysis, and freeze drying was found to be effective for concentrating the rMnP from 2,500 U/L in the P. pastoris bioreactor culture to 30,000 U/L in 0.1 M potassium phosphate buffer pH 6. The rMnP recovery yield was 60% and the purity was 1–4%. By using 0.1 g/L heme during the fed‐batch cultivation, the heme content of the final enzyme preparation could be reduced by 97%, and had sufficiently high rMnP activity and low enough color to be suitable for pulp bleaching experiments. Biotechnol. Bioeng. 2008;99: 540–549. © 2007 Wiley Periodicals, Inc.
Redesigning the substrate specificity of ω‐aminotransferase for the kinetic resolution of aliphatic chiral amines
Authors: Cho Byung‐Kwan , Park Hyung‐Yeon , Seo Joo‐Hyun , Kim Juhan , Kang Taek‐Jin , Lee Bon‐Su , Kim Byung‐Gee
Published: August 2007

Substrate specificity of the ω‐aminotransferase obtained from Vibrio fluvialis (ω‐ATVf) was rationally redesigned for the kinetic resolution of aliphatic chiral amines. ω‐ATVf showed unique substrate specificity toward aromatic amines with a high enantioselectivity (E > 100) for (S)‐enantiomers. However, the substrate specificity of this enzyme was much narrower toward aliphatic amines. To overcome the narrow substrate specificity toward aliphatic amines, we redesigned the substrate specificity of ω‐ATVf using homology modeling and the substrate structure‐ activity relationship. The homology model and the substrate structure‐activity relationship showed that the active site of ω‐ATVf consists of one large substrate‐binding site and another small substrate‐binding site. The key determinant in the small substrate‐binding site was D25, whose role was expected to mask R415 and to generate the electrostatic repulsion with the substrate's α‐carboxylate group. In the large substrate‐binding site, R256 was predicted to recognize the α‐carboxylate group of substrate thus obeying the dual substrate recognition mechanism of aminotransferase subgroup II enzymes. Among the several amino acid residues in the large substrate‐binding site, W57 and W147, with their bulky side chains, were expected to restrict the recognition of aliphatic amines. Two mutant enzymes, W57G and W147G, showed significant changes in their substrate specificity such that they catalyzed transamination of a broad range of aliphatic amines without losing the original activities toward aromatic amines and enantioselectivity. Biotechnol. Bioeng. 2008;99: 275–284. © 2007 Wiley Periodicals, Inc.
Development of a simple and rapid method for producing non‐fucosylated oligomannose containing antibodies with increased effector function
Authors: Zhou Qun , Shankara Srinivas , Roy Andre , Qiu Huawei , Estes Scott , McVie‐Wylie Alison , Culm‐Merdek Kerry , Park Anna , Pan Clark , Edmunds Tim
Published: August 2007

Glycosylation in the Fc region of antibodies has been shown to play an important role in antibody function. In the current study, glycosylation of human monoclonal antibodies was metabolically modulated using a potent α‐mannosidase I inhibitor, kifunensine, resulting in the production of antibodies with oligomannose‐type N‐glycans. Growing Chinese hamster ovary cells for 11 days in batch culture with a single treatment of kifunensine was sufficient to elicit this effect without any significant impact on cell viability or antibody production. Antibodies expressed in the presence of kifunensine at a concentration as low as 60 ng/mL contained mainly oligomannose‐type glycans and demonstrated increased ADCC activity and affinity for FcγRIIIA, but reduced C1q binding. Although the kifunensine‐mediated shift to oligomannose‐type glycans could, in theory, result in rapid clearance of the antibody through increased mannose receptor binding, the serum levels of antibody in mice were not significantly altered up to 168 h following injection. The use of kifunensine provides a simple and rapid method for the production of antibodies with increased ADCC without the time‐consuming need to re‐engineer either the antibody molecule or the host cell line. Biotechnol. Bioeng. 2008;99: 652–665. © 2007 Wiley Periodicals, Inc.
Cells for bioartificial liver devices: The human hepatoma‐derived cell line C3A produces urea but does not detoxify ammonia
Authors: Mavri‐Damelin Demetra , Damelin Leonard H. , Eaton Simon , Rees Myrddin , Selden Clare , Hodgson Humphrey J.F.
Published: August 2007

Extrahepatic bioartificial liver devices should provide an intact urea cycle to detoxify ammonia. The C3A cell line, a subclone of the hepatoma‐derived HepG2 cell line, is currently used in this context as it produces urea, and this has been assumed to be reflective of ammonia detoxification via a functional urea cycle. However, based on our previous findings of perturbed urea‐cycle function in the non‐urea producing HepG2 cell line, we hypothesized that the urea produced by C3A cells was via a urea cycle‐independent mechanism, namely, due to arginase II activity, and therefore would not detoxify ammonia. Urea was quantified using 15N‐ammonium chloride metabolic labelling with gas chromatography–mass spectrometry. Gene expression was determined by real‐time reverse transcriptase‐PCR, protein expression by western blotting, and functional activities with radiolabelling enzyme assays. Arginase inhibition studies used Nω‐hydroxy‐nor‐L‐arginine. Urea was detected in C3A conditioned medium; however, 15N‐ammonium chloride‐labelling indicated that 15N‐ammonia was not incorporated into 15N‐labelled urea. Further, gene expression of two urea cycle genes, ornithine transcarbamylase and arginase I, were completely absent. In contrast, arginase II mRNA and protein was expressed at high levels in C3A cells and was inhibited by Nω‐hydroxy‐nor‐L‐arginine, which prevented urea production, thereby indicating a urea cycle‐independent pathway. The urea cycle is non‐functional in C3A cells, and their urea production is solely due to the presence of arginase II, which therefore cannot provide ammonia detoxification in a bioartificial liver system. This emphasizes the continued requirement for developing a component capable of a full repertoire of liver function. Biotechnol. Bioeng. 2008;99: 644–651. © 2007 Wiley Periodicals, Inc.
Genetic engineering of a lysosomal enzyme fusion protein for targeted delivery across the human blood‐brain barrier
Authors: Boado Ruben J. , Zhang Yun , Zhang Yufeng , Xia Chun‐fang , Wang Yuntao , Pardridge William M.
Published: August 2007

Mucopolysaccharidosis Type I, Hurler's Syndrome, is a lysosomal storage disorder that affects the brain. The missing enzyme, α‐L‐iduronidase (IDUA), does not cross the blood‐brain barrier (BBB). To enable BBB transport of the enzyme, human IDUA was fused to the carboxyl terminus of the heavy chain of a chimeric monoclonal antibody (MAb) to the human insulin receptor (HIR). The HIRMAb crosses the BBB on the endogenous insulin receptor, and acts as a molecular Trojan horse to ferry into brain the IDUA. Transfection of COS cells resulted in high levels of IDUA enzyme activity both in the medium and in the intracellular space. The size of the fusion heavy chain, as measured with Western blotting and antibodies to either human IDUA or human IgG, was increased about 80 kDa, relative to the size of the heavy chain of the parent HIRMAb. The IDUA enzyme specific activity of the affinity purified HIRMAb‐IDUA fusion protein was 363 ± 37 U/µg protein, which is comparable to specific activity of recombinant IDUA. The accumulation of glycosoaminoglycans in Hurler fibroblasts was decreased 70% by treatment with the HIRMAb‐IDUA fusion protein. Confocal microscopy showed targeting of the fusion protein to the lysosome. The HIRMAb‐IDUA fusion protein bound with high affinity to the HIR, and was rapidly transported into the brain of the adult Rhesus monkey following intravenous administration. The HIRMAb‐IDUA fusion protein is a new treatment for Hurler's syndrome, which has been specifically engineered to cross the human BBB. Biotechnol. Bioeng. 2008;99: 475–484. © 2007 Wiley Periodicals, Inc.
Large‐scale production of endotoxin‐free plasmids for transient expression in mammalian cell culture
Authors: Rozkov Aleksei , Larsson Bert , Gillström Stefan , Björnestedt Robert , Schmidt Stefan R.
Published: August 2007

Transient expression of recombinant proteins in mammalian cell culture in a 100‐L scale requires a large quantity of plasmid that is very labour intensive to achieve with shake flask cultures and commercially available plasmid purification kits. In this paper we describe a process for plasmid production in 100‐mg scale. The fermentation is carried out in a 4‐L fed‐batch culture with a minimal medium. The detection of the end of batch and triggering the exponential (0.1 h−1) feed profile was unattended and controlled by Multi‐fermenter Control System. A restricted specific growth rate in fed‐batch culture increased the specific plasmid yield compared to batch cultures with minimal and rich media. This together with high biomass concentration (68–107 g L−1 wet weight) achieves high volumetric yields of plasmid (95–277 mg L−1 depending on the construct). The purification process consisted of alkaline lysis, lysate clarification and ultrafiltration, two‐phase extraction with Triton X‐114 for endotoxin removal, anion‐exchange chromatography as a polishing step, ultrafiltration and sterile filtration. Both fermentation and purification processes were used without optimisation for production of four plasmids yielding from 39 to 163 mg of plasmids with endotoxin content of 2.5 EU mg−1 or less. Biotechnol. Bioeng. 2008;99: 557–566. © 2007 Wiley Periodicals, Inc.
The bactericidal effect of ultraviolet and visible light on Escherichia coli
Authors: Vermeulen Natasha , Keeler Werden J. , Nandakumar Kanavillil , Leung Kam Tin
Published: August 2007

The bactericidal radiation dosages at specific wavelengths in the ultraviolet (UV)–visible spectrum are not well documented. Such information is important for the development of new monochromatic bactericidal devices to be operated at different wavelengths. In this study, radiation dosages required to cause mortality of an Escherichia coli strain, ATCC 25922, at various wavelengths between 250 and 532 nm in the UV and visible spectrum were determined. Radiation at 265 nm in the UV region was most efficient in killing the E. coli cells and 100% mortality was achieved at a dose of 1.17 log mJ/cm2. In the visible spectrum, the radiation dosages required for a one‐log reduction of the E. coli cell density at 458 and 488 nm were 5.5 and 6.9 log mJ/cm2, respectively. However, at 515 and 532 nm, significant killing was not observed at radiation dosage up to 7 log mJ/cm2. Based on the cell survival data at various radiation dosages between 250 and 488 nm, a predictive equation for the survival of E. coli cells is derived, namely log(S/S0) =  −(1.089 × 107 e−0.0633λ)D. The symbols, S0, S, λ, and D, represent initial cell density, cell density after irradiation, wavelength of the radiation and radiation dosage, respectively. The proportion of the surviving E. coli cells decreases exponentially with the increase in radiation dosage at a given wavelength. In addition, the radiation dose required for killing a certain fraction of the E. coli cells increases exponentially as the wavelength of radiation increases. Bioeng. 2008;99: 550–556. © 2007 Wiley Periodicals, Inc.
Accelerated cell line development using two‐color fluorescence activated cell sorting to select highly expressing antibody‐producing clones
Authors: Sleiman Robert J. , Gray Peter P. , McCall Martin N. , Codamo Joe , Sunstrom Noelle‐Ann S.
Published: August 2007

The success of engineered monoclonal antibodies as biopharmaceuticals has generated considerable interest in strategies designed to accelerate development of antibody expressing cell lines. Stable mammalian cell lines that express therapeutic antibodies at high levels typically take 6–12 months to develop. Here we describe a novel method to accelerate selection of cells expressing recombinant proteins (e.g., antibodies) using multiparameter fluorescence activated cell sorting (FACS) in association with dual intracellular autofluorescent reporter proteins. The method is co‐factor‐independent and does not require complex sample preparation. Chinese hamster ovary (CHO) clones expressing high levels of recombinant antibody were selected on the basis of a two‐color FACS sorting strategy using heavy and light chain‐specific fluorescent reporter proteins. We were able to establish within 12 weeks of transfection cell lines with greater than a 38‐fold increase in antibody production when compared to the pool from which they were isolated, following a single round of FACS. The method provides a robust strategy to accelerate selection and characterization of clones and builds a foundation for a predictive model of specific productivity based upon on two‐color fluorescence. Biotechnol. Bioeng. 2008;99: 578–587. © 2007 Wiley Periodicals, Inc.
Anti‐Carbohydrate Antibodies Elicited by Polyvalent Display on a Viral Scaffold
Authors: Kaltgrad Eiton , Sen Gupta Sayam , Punna Sreenivas , Huang Cheng‐Yuan , Chang Aileen , Wong Chi‐Huey , Finn M. G. , Blixt Ola
Published: August 2007

Tetra‐ and hexasaccharides were arrayed on the exterior surface of cowpea mosaic virus by using a copper‐catalyzed azide–alkyne cycloaddition reaction. Inoculation of chickens with these virus conjugates gave rise to large quantities of polyclonal anti‐glycan IgY antibodies that displayed excellent avidity and specificity on analysis with printed glycan microarrays. Avian IgY antibodies are produced in significantly higher yield than is possible for mouse or rabbit IgG, and exhibit reduced cross reactivity with native mammalian proteins. For a tri‐LacNAc antigen, affinity purification against immobilized mono‐LacNAc was necessary to provide a set of antibodies with specific binding properties. Comparable performance was observed for the virus‐based polyclonal versus a commercial monoclonal antibody raised against the globo‐H tetrasaccharide; this highlights the utility of the glycan microarray for both quality control and rapid in‐depth analysis. Virus–carbohydrate conjugates are promising candidates for development in diagnostic and immunotherapeutic applications.
Influencing models to improve their predictions of standard samples
Authors: DiFoggio Rocco
Published: August 2007

This paper generalizes the Lagrange multiplier solution for a regression subject to inhomogeneous (d ≠ 0) linear equality constraints, Vb′= d, to the case where these constraints are only partially satisfied. It extends the work of an earlier paper that generalized the Lagrange multiplier solution for a regression subject to homogeneous (d = 0) linear equality constraints, Vb′ = 0. With this method, we can insure that our chemometric models predict known standard samples more accurately by making such samples more influential. For example, we can include samples from a particular locale in a calibration set as sample ‘standards’ to create a ‘tuned’ model, b′ from a generic model, b, that is based on samples from a wider geographical area. We introduce new ways to adjustably control a sample's influence and show why they are preferable to simply including that sample multiple times. One new way is to use simultaneous counterbalanced sample‐pair distortion of both X and Y blocks. Another is to generalize the Lagrange multiplier solution that allows the constraints Vb′ = d to be only partially satisfied, which is important when the constraints interfere so that a perfect fit to one standard sample prevents a perfect fit to another standard sample. Some advantages of these new methods are that they cause no frequency filtering of the X‐block, which might remove information, and they allow the user to minimize the standard error of prediction by optimizing influence. Copyright © 2007 John Wiley & Sons, Ltd.
Small sample and selection bias effects in calibration under latent factor regression models
Authors: Sundberg Rolf
Published: August 2007

We study bias of predictors when a multivariate calibration procedure has been applied to relate a scalary(concentration of an analyte, say) to a vector x (spectral intensities, say). The model for data is assumed to be of latent factor regression type, with multiple regression models and errors‐in‐variables models as special cases. The calibration procedures explicitly studied are OLSR, PLSR and PCR. Often a practical device to increase precision in the calibration is to selectymore or less systematically, in order to achieve increased variation (overdispersion). However, this leads to biased coefficients in the predictor, possible to see when observed ityis regressed on predicted ŷ (x) for a separate validation set. Another bias effect is a sample size effect, increasing with reduced calibration sample size and with increasing dimension of x (absent when x is univariate). Formulae are given for these bias effects, both separately and in combination, and the formulae are illustrated and compared with simulation results. As a qualitative example, PLSR and PCR are less sensitive than OLSR to small samples, but equally sensitive to selection. Copyright © 2007 John Wiley & Sons, Ltd.
Structural, Kinetic, and Theoretical Studies on Models of the Zinc‐Containing Phosphodiesterase Active Center: Medium‐Dependent Reaction Mechanisms
Authors: Selmeczi Katalin , Michel Carine , Milet Anne , Gautier‐Luneau Isabelle , Philouze Christian , Pierre Jean‐Louis , Schnieders David , Rompel Annette , Belle Catherine
Published: August 2007

Dinuclear zinc(II) complexes [Zn2(bpmp)(μ‐OH)](ClO4)2 (1) and [Zn2(bpmp)(H2O)2](ClO4)3 (2) (H‐BPMP=2,6‐bis[bis(2‐pyridylmethyl)aminomethyl]‐4‐methylphenol) have been synthesized, structurally characterized, and pH‐driven changes in metal coordination observed. The transesterification reaction of 2‐hydroxypropyl p‐nitrophenyl phosphate (HPNP) in the presence of the two complexes was studied both in a water/DMSO (70:30) mixture and in DMSO. Complex 2 was not reactive whereas for 1 considerable rate enhancement of the spontaneous hydrolysis reaction was observed. A detailed mechanistic investigation by kinetic studies, spectroscopic measurements (1H, 31P NMR spectroscopy), and ESI‐MS analysis in conjunction with ab initio calculations was performed on 1. Based on these results, two medium‐dependent mechanisms are presented and an unusual bridging phosphate intermediate is proposed for the process in DMSO.
Transsialidase from Trypanosoma cruzi for Regio‐ and Stereoselective Synthesis of N‐Acyl‐Modified Sialylated Oligosaccharides and Measurement of Transfer Rates
Authors: Schroven Andreas , Meinke Sebastian , Ziegelmüller Patrick , Thiem Joachim
Published: August 2007

Recombinant transsialidase from Trypanosoma cruzi (TcTS) was used for the sialylation with natural and non‐natural derivatives of neuraminic acid. Neu5Ac‐α(2→3)‐Gal‐β(1→6)‐Glc‐αOMe was prepared in 80 % yield. Correspondingly, the modified trisaccharide derivatives Neu5Prop‐α(2→3)‐Gal‐β(1→6)‐Glc‐αOMe (32 %) and Neu5Gc‐α(2→3)‐Gal‐β(1→6)‐Glc‐αOMe (Prop=propanoyl, Gc=glycolyl) were obtained in 60 % yield, respectively.
Extracardiac Medical and Neuromuscular Implications in Restrictive Cardiomyopathy
Authors: Stöllberger Claudia , Finsterer Josef
Published: August 2007

Restrictive cardiomyopathy (RCMP) is characterized by restrictive filling and reduced diastolic volume of either or both ventricles with normal or near‐normal systolic function and wall thickness. It may occur idiopathically or as a cardiac manifestation of systemic diseases such as scleroderma, amyloidosis, Churg‐Strauss syndrome, cystinosis, sarcoidosis, lymphoma, Gaucher's disease, hemochromatosis, Fabry's disease, pseudoxanthoma elasticum, hypereosinophilic syndrome, carcinoid, Noonan's syndrome, reactive arthritis, or Werner's syndrome and various neuromuscular disorders. Whereas in idiopathic RCMP the therapeutic options are only treatment of cardiac congestion, in cases with an underlying disorder, a causal therapy may be available. Patients with RCMP should be investigated as soon as the cardiac diagnosis is established for extracardiac diseases to detect a possibly treatable cause of RCMP before the disease becomes intractable. These investigations include a diligent clinical history and examination, blood tests, and ophthalmologic, otologic, dermatologic, gastroenterologic, nephrologic, hematologic, and neurologic examinations. If extracardiac examinations do not reveal a plausible cause for RCMP, endomyocardial biopsy is indicated. Copyright © 2007 Royal Meteorological Society
Inflammatory Biomarkers are not Predictive of Intermediate‐term Risk of Ventricular Tachyarrhythmias in Stable CHF Patients
Authors: Konstantino Yuval , Kusniec Jairo , Reshef Tamar , David‐Zadeh Ofer , Mazur Alexander , Strasberg Boris , Battler Alexander , Haim Moti
Published: August 2007

Background:

Elevated levels of inflammatory biomarkers and brain natriuretic peptide (BNP) are associated with increased mortality in patients with heart failure (HF).

Hypothesis:

The aim of the current study was to assess the correlation between circulating biomarkers and ventricular tachyarrhythmias among patients with HF.

Methods:

Blood samples from 50 stable ambulatory HF patients with moderate to severe systolic left ventricular (LV) dysfunction and an implantable cardioverter defibrillator (ICD) were analyzed for interleukin 6 (IL‐6), tumor necrosis factor‐alpha (TNF‐α), high‐sensitivity C‐reactive protein (hsCRP) and BNP. Thereafter, the patients were followed for a mean period of 152 ± 44 days, during which ventricular tachyarrhythmias were recorded by the ICDs.

Results:

Follow‐up data were obtained from 47 patients. Of them, 45 (96%) had ischemic cardiomyopathy, 38 (81%) had New York Heart Association class I–II, 43 (91%) were males, and the mean age was 68.6 ± 11.1 years. During follow‐up, 5 patients (11%) had nonsustained ventricular tachycardia (NSVT), 6 patients (13%) had sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and 36 patients (76%) had no events. The circulating biomarkers' levels upon enrollment were not significantly different between patients who subsequently had NSVT or VT/VF and patients who were free of events.

Conclusions:

No correlation was found between plasma levels of IL‐6, TNF‐α, hsCRP and BNP and ventricular arrhythmic events among stable HF patients during an intermediate term follow‐up of 5.1 months. Further studies are still required to assess the association between these biomarkers and long‐term risk of ventricular tachyarrhythmia. Copyright © 2007 Wiley Periodicals, Inc.
Normalization of Abnormal T‐waves During Stress Testing does not Identify Patients with Reversible Perfusion Defects
Authors: Loeb Henry S. , Friedman Nicholas C.
Published: August 2007

Objective:

To determine if T‐wave normalization during exercise or dobutamine stress testing identified patients with myocardial ischemia as indicated by reversible perfusion defects.

Methods:

Exercise or dobutamine stress tests with perfusion scintigraphy were performed in 1,173 patients with abnormal T‐waves on their baseline electrocardiograms. The results of perfusion scintigraphy were compared in patients with and without stress‐induced T‐wave normalization.

Results:

Only 33 of 270 patients with reversible perfusion defects (12.2%) had T‐wave normalization during stress while 76.4% of 140 patients who had T‐wave normalization during stress did not have a reversible perfusion defect. Results were similar for patients who did or did not reach 85% of their maximal predicted heart rate, for patients with and without Q‐wave infarction on the baseline EKG and for patients who did or did not have ischemic ST‐segment depression during stress.

Conclusions:

T‐wave normalization during stress testing has low sensitivity and poor positive predictive value for stress‐induced reversible myocardial ischemia. Copyright © 2007 Wiley Periodicals, Inc.
Severity of Coronary Artery Disease in Obese Patients Undergoing Coronary Angiography: “Obesity Paradox” Revisited
Authors: Niraj Ashutosh , Pradahan Jyotiranjan , Fakhry Hesham , Veeranna Vikas , Afonso Luis
Published: August 2007

Background:

Recent studies have highlighted the existence of an ‘obesity paradox’ in patients undergoing coronary angiography, i.e., a high body mass Index (BMI) is associated with less severe coronary lesions. We sought to confirm the existence of this phenomenon in the US patient population.

Methods:

Study subjects included 770 consecutive patients (470 men, 428 African‐Americans, 212 Caucasians) referred for coronary angiography to a tertiary care center. Duke myocardial jeopardy score, a prognostication tool predictive of 1‐year mortality in coronary artery disease (CAD) patients, was assigned to angiographic data. Patients were classified according to their BMI (kg/m2) as normal (21–24), overweight (25–29), obesity class I (30–34), class II (35–39) and class III (40 or above).

Results:

Patients in the increasing obesity class had a higher prevalence of diabetes, hypertension and dyslipidemia and were more likely to be women. A negative correlation was observed between BMI and age (R = − 0.15 p < 0.001) as well as between BMI and Duke Jeopardy score (r = − 0.07, p < 0.05) indicating that patients with higher BMI were referred for coronary angiography at a younger age, and had a lower coronary artery disease (CAD) burden. BMI was not an independent predictor of coronary lesion severity on multivariate stepwise linear regression analysis.

Conclusion:

Obese patients are referred for coronary angiography at an earlier age and have a lower CAD burden lending further credence to the existence of an apparent “obesity paradox”. However, obesity per se, after adjustment for comorbidities, is not an independent predictor of severity of coronary artery disease. Copyright © 2007 Wiley Periodicals, Inc.
Octa‐O‐bis‐(R,R)‐Tartarate Ditellurane (SAS)—a Novel Bioactive Organotellurium(IV) Compound: Synthesis, Characterization, and Protease Inhibitory Activity
Authors: Yosef Sigal , Brodsky Miri , Sredni Benjamin , Albeck Amnon , Albeck Michael
Published: August 2007

Octa‐O‐bis‐(R,R)‐Tartarate Ditellurane (SAS) is a new TeIV compound, comprised of two tellurium atoms, each liganded by four oxygen atoms from two carboxylates and two alkoxides of two tartaric acids. Unlike many other TeIV compounds, SAS was highly stable in aqueous solution. It interacted with thiols to form an unstable Te(SR)4 product. The product of the interaction of SAS with cysteine was isolated and characterized by mass spectroscopy and elemental analysis. SAS selectively inactivated cysteine proteases, but it did not inactivate other families of proteolytic enzymes. It displayed selectivity towards the cysteine protease cathepsin B, a human enzyme of pharmaceutical interest, with a second order rate constant ki/Ki=5900 M−1 s−1.
Contra‐thermodynamic Behavior in Intermolecular Hydrogen Transfer of Alkylperoxy Radicals
Authors: Pfaendtner Jim , Broadbelt Linda J.
Published: August 2007

Quantum chemical investigation of bimolecular hydrogen transfer involving alkylperoxy radicals, a key reaction family in the free‐radical oxidation of hydrocarbons, was performed to establish structure–reactivity relationships. Eight different reactions were investigated featuring four different alkane substrates (methane, ethane, propane and isobutane) and two different alkylperoxy radicals (methylperoxy and iso‐propylperoxy). Including forward and reverse pairs, sixteen different activation energies and enthalpies of reaction were used to formulate structure–reactivity relationships to describe this chemistry. We observed that the enthalpy of formation of loosely bound intermediate states has a strong inverse correlation with the overall heat of reaction and that this results in unique contra‐thermodynamic behavior such that more exothermic reactions have higher activation barriers. A new structure–reactivity relationship was proposed that fits the calculated data extremely well: EA=Eo+αΔHrxn where α=−0.10 for ΔHrxn<0, and α=1.10 for ΔHrxn>0 and Eo=3.05 kcal mol−1.
57Fe Mössbauer Spectroscopy and Electron Microscopy Study of Metal Extraction from CuFe2O4 Electrodes in Lithium Cells
Authors: Bomio Mauricio , Lavela Pedro , Tirado José Luis
Published: August 2007

Active CuFe2O4 electrode materials for lithium cells are produced by thermal decomposition of a citrate precursor. The precipitation of the metal citrate is carried out by a freeze‐drying procedure. A tetragonally distorted spinel structure is prepared by the decomposition of a citrate precursor. Samples free of impurities are obtained depending on the annealing temperature. The sample heated at 800 °C performed at 470 mAh g−1 after 50 cycles. Electron microscopy is used as the ultimate technique to monitor the morphological changes upon the reversible conversion reaction. Detachment of metallic particles from the starting material, the formation of a polymeric organic film, and the subsequent removal on charging are discussed as determining factors in the electrochemical behaviour of this oxide as an electrode versus lithium. The growth of metallic iron aggregates is inferred from the 57Fe Mössbauer spectra.