bluuebunny/crossref_metadata_2025_split huggingface dataset:
A combined method for determining inhibition type, kinetic parameters, and inhibition coefficients for aerobic cometabolism of 1,1,1‐trichloroethane by a butane‐grown mixed culture
Authors: Kim Young , Arp Daniel J. , Semprini Lewis 
Published: August 2002

AbstractA combined method for determining inhibition type, kinetic parameters, and inhibition coefficients is developed and presented. The method was validated by applying it to data obtained from batch kinetics of the aerobic cometabolism of 1,1,1‐trichloroethane (1,1,1‐TCA) by a butane‐grown mixed culture. The maximum degradation rates (kmax) and half‐saturation coefficients (Ks) were independently determined in single compound tests, and compared with those obtained from inhibition tests. The inhibition type was determined using direct linear plots at various substrate and inhibitor concentrations. Kinetic parameters (kmax and Ks) and inhibition coefficients (Kic and Kiu) were determined by nonlinear least squares regression (NLSR) fits of the inhibition model determined from the direct linear plots. Initial guesses of the kinetic parameters for NLSR were determined from linearized inhibition equations that were derived from the correlations between apparent maximum degradation rates (k) and/or the apparent half‐saturation coefficient (K) and the kmax, Ks, and inhibitor concentration (IL) for each inhibition equation. Two different inhibition types were indicated from the direct linear plots: competitive inhibition of 1,1,1‐TCA on butane degradation, and mixed inhibition of 1,1,1‐TCA transformation by butane. Good agreement was achieved between independently measured kmax and Ks values and those obtained from both NLSR and the linearized inhibition equations. The initial guesses of all the kinetic parameters determined from linear plots were in the range of the values estimated from NLSR analysis. Overall the results show that use of the direct linear plot method to identify the inhibition type, coupled with initial guesses from linearized plots for NLSR analysis, results in an accurate method for determining inhibition types and coefficients. Detailed studies with pure cultures and purified enzymes are needed to further demonstrate the utility of this method. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 564–576, 2002; DOI 10.1002/bit.10145
Connection between gene dosage and protein stability revealed by a high‐yield production of recombinant proteins in an E. coli LexA1(Ind−) background
Authors: Medina Manel G. , Carbonell Xavier , Villaverde Antonio 
Published: August 2002

AbstractBacterial production of a plasmid‐encoded bacteriophage P22 tailspike protein shows different yield and impact on cell viability in RecA+ LexA+, RecA− LexA+ and RecA+ LexA1(Ind−) backgrounds. In a LexA1(Ind−) context, we have observed lesser toxicity and higher productivity than in the wild‐type strain, in which the bacterial growth was inhibited after induction of recombinant gene expression. Also, a negative effect of the incubation temperature on the growth of producing cells was also detected. By exploring the molecular basis of these inhibitory events, we found a connection between the dosage of the recombinant gene and the proteolytic stability of the encoded protein. Under both genetic and environmental conditions favoring higher plasmid copy number and consequently increasing the synthesis rate of the recombinant protein, enhanced protein degradation was observed in parallel with an important growth inhibition. Altogether, the obtained data suggest the existence of a critical concentration of recombinant protein over which cell proteolysis is stimulated at rates not compatible with optimal physiological conditions for bacterial growth. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 722–730, 2002.
Controlled shear affinity filtration (CSAF): A new technology for integration of cell separation and protein isolation from mammalian cell cultures
Authors: Vogel Jens H. , Anspach Birger , Kroner Karl‐Heinz , Piret James M. , Haynes Charles A. 
Published: August 2002

AbstractControlled shear affinity filtration (CSAF) integrates animal cell separation and product isolation in a single unit operation through the use of a specifically designed rotating disk filter with incorporated membrane chromatography column. Because of the decoupling of shear force and pressure generation and the specific hydrodynamics of the system, shear rates can be easily optimized and precisely controlled to maximize filtration performance while viability of the shear sensitive animal cells is maintained. In this study, the general methodology is demonstrated using the integration of Chinese hamster ovary cell separation and isolation of recombinant tissue plasminogen activator (t‐PA) as a model example. Direct capture of t‐PA from cell culture broth was realized by using custom‐made affinity membranes with lysine as a robust, small molecular weight affinity ligand. Small‐scale t‐PA adsorption experiments, as well as microfiltration experiments, were used to design the integrated CSAF process. A Chinese hamster ovary batch culture was processed with a lab‐scale prototype, yielding 86% of the t‐PA in the concentrated, particle‐free eluate, whereas 95% of the bulk protein was removed. Because the viability of the cells is not significantly affected and high specific flux rates can be achieved, the CSAF technology should also be well suited for continuous perfusion with integrated product isolation. A truly continuous operation could be realized with two systems in tandem configuration. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 806–814, 2002.
Scale‐down model to simulate spatial pH variations in large‐scale bioreactors
Authors: Amanullah A. , McFarlane C. M. , Emery A. N. , Nienow A. W. 
Published: August 2002

AbstractFor the first time a laboratory‐scale two‐compartment system was used to investigate the effects of pH fluctuations consequent to large scales of operation on microorganisms. pH fluctuations can develop in production‐scale fermenters as a consequence of the combined effects of poor mixing and adding concentrated reagents at the liquid surface for control of the bulk pH. Bacillus subtilis was used as a model culture since in addition to its sensitivity to dissolved oxygen levels, the production of the metabolites, acetoin and 2,3‐butanediol, is sensitive to pH values between 6.5 and 7.2. The scale‐down model consisted of a stirred tank reactor (STR) and a recycle loop containing a plug flow reactor (PFR), with the pH in the stirred tank being maintained at 6.5 by addition of alkali in the loop. Different residence times in the loop simulated the exposure time of fluid elements to high values of pH in the vicinity of the addition point in large bioreactors and tracer experiments were performed to characterise the residence time distribution in it. Since the culture was sensitive to dissolved oxygen, for each experiment with pH control by adding base into the PFR, equivalent experiments were conducted with pH control by addition of base into the STR, thus ensuring that any dissolved oxygen effects were common to both types of experiments. The present study indicates that although biomass concentration remained unaffected by pH variations, product formation was influenced by residence times in the PFR of 60 sec or longer. These changes in metabolism are thought to be linked to both the sensitivity of the acetoin and 2,3‐butanediol‐forming enzymes to pH and to the inducing effects of dissociated acetate on the acetolactate synthase enzyme. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 390–399, 2001.
Encapsulation of proteins by layer‐by‐layer adsorption of polyelectrolytes onto protein aggregates: Factors regulating the protein release
Authors: Balabushevitch Nadejda G. , Sukhorukov Gleb B. , Moroz Natalia A. , Volodkin Dmitry V. , Larionova Natalia I. , Donath Edwin , Mohwald Helmuth 
Published: August 2002

AbstractA novel method of protein encapsulation is proposed. Preformed protein aggregates are covered with polyelectrolyte layers by means of layer‐by‐layer adsorption. The polyelectrolyte membrane prevents protein leakage out of the capsule. Using chymotrypsin as a model enzyme the capsule wall selective permeability was demonstrated for substrates and inhibitors of different molecular weight and solubility. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 207–213, 2001.
Water‐based nanoparticulate polymeric system for protein delivery: permeability control and vaccine application
Authors: Prokop Ales , Kozlov Evgenii , Newman Gale W. , Newman Mark J. 
Published: August 2002

AbstractThe idea of using polymeric nanoparticles as drug carriers is receiving an increasing amount of attention both in academia and industry, Nanoparticles have a number of potential applications in protein, drug and vaccine delivery, as well as gene therapy applications. In this article, we focus on this unique drug delivery technology as a method to control the release rate of substances, not only for protein delivery but also for delivering an experimental vaccine immunogen. Nanoparticles were assembled on the basis of ionic interaction between water‐soluble polymers so that the resulting particles were stable in physiologic media. Among the typical polymers used to assemble nanoparticles, different polysaccharides, natural amines, and poly‐amines were investigated. The entrapped substances tested included a protein and antigens. Polydextran aldehyde was incorporated into the particle core, to enable physiologic cross‐linking as a method to control permeability. This resulted in long‐term retention of substances that would otherwise rapidly leak out of the nanoparticles. Results of cross‐linking experiments clearly demonstrated that the release rate could be substantially reduced, depending on the degree of cross‐linking. For vaccine antigen delivery tests, we measured an antibody production after subcutaneous and oral administration. The data indicated that only the cross‐linked antigen was immunogenic when the oral route of administration was used. The data presented in this article address primarily the utility of nanoparticulates for oral delivery of vaccine antigen. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 459–466, 2002.
Disposition of triazolam in the rat by brain microdialysis and semi‐micro column high‐performance liquid chromatography with UV absorbance detection
Authors: Nakashima Kenichiro , Yamamoto Kazumi , Al‐Dirbashi Osama Y. , Nakashima Mihoko N. 
Published: August 2002

AbstractA semi‐micro column high‐performance liquid chromatography with ultraviolet detection for the determination of triazolam is described. The method was applied to determine plasma and brain microdialysate concentrations of triazolam after single intravenous bolus of 2.5 mg/kg to rat. The separation was achieved on a 250 × 1.5 mm i.d. C18 column and the column effluent was monitored at 222 nm. The detection limits at a signal‐to‐noise ratio of 3 obtained using spiked plasma and artificial cerebrospinal fluid were 2.1 and 0.7 ng/mL, respectively. The intra‐ and inter‐day reproducibility of the present method were satisfactory with the highest relative standard deviation of 9.1 (n ≥ 5). The present method was successfully applied to study the disposition of triazolam in rat (n = 5) by analyzing plasma and brain microdialysate samples. Copyright © 2002 John Wiley & Sons, Ltd.
High‐performance liquid chromatographic method with ultraviolet detection for the determination of dapsone and its hydroxylated metabolite in human plasma
Authors: Kwadijk S. , Toraño J. Sastre 
Published: August 2002

AbstractA validated high‐performance liquid chromatographic method with ultraviolet detection for the quantitative determination of dapsone (4,4′‐diaminodifenyl sulfone, DDS) and a metabolite, hydroxylaminodapsone (4‐amino‐4‐hydroxylaminodiphenyl sulfone, DDS‐NOH), in human plasma is described. Human plasma was deproteinized with acetone and the clear supernatant solution after centrifugation was evaporated to dryness under a gentle stream of nitrogen at 70°C. The residue was dissolved in a mixture of HPLC eluent and acetone (18:5 v/v) and an aliquot of this solution (50 µL) was injected onto the HPLC column. Dapsone, hydroxylaminodapsone and diazoxide as internal standard, were separated within 10 min by isocratic elution with water:acetonitrile:glacial acetic acid:triethylamine (80:20:1.0:0.5 by volume) as eluent. Detection was by ultraviolet at the wavelength of 295 nm. The within‐day repeatability coefficients of variation were 3–5% for dapsone (0.301–20.0 mg/L, n = 5) and 3–5% for hydroxylaminodapsone (0.0948–6.32 mg/L, n = 5), whereas the between‐day repeatability coefficients of variation were 3–8% (0.301–20.0 mg/L, n = 5) for dapsone and 4–10% for hydroxylaminodapsone (0.0948–6.32 mg/L, n = 5). The mean recoveries ­were 92–107% (0.301–20.0 mg/L, n = 2), 80–82% (0.0948–6.32 mg/L, n = 2) and 88% (0.0200 mg/mL, n = 5), for dapsone, hydroxylaminodapsone and diazoxide, respectively. The average correlation coefficient of the calibration curve was 0.99988 (n = 5) for dapsone at a concentration range of 0.301–20.0 mg/L, whereas the average correlation coefficient of the hydroxylaminodapsone calibration curve was 0.99981 (n = 5) at a concentration range of 0.0948–6.32 mg/L. The limits of detection were 0.00200 and 0.0470 mg/L for dapsone and hydroxylaminodapsone, respectively. The method is suitable for drug level monitoring and for pharmacokinetic studies. Copyright © 2002 John Wiley & Sons, Ltd.
Removal of poliovirus type 1 from a protein mixture using an immunoaffinity chromatography column
Authors: Cameron‐Smith Rachel , Harbour Colin 
Published: August 2002

AbstractAn immunoaffinity matrix was prepared using human polyclonal antibody (Intragam®) attached to Sepharose® 4B activated with CNBr. The immunoaffinity matrix was then assessed with regard to its capacity to remove viruses. The challenge virus, poliovirus type 1 was loaded in high titre in either PBS or a preparation derived from human plasma known as supernatant II + III. This fraction is depleted of IgG and is used to prepare human albumin. It was shown that an average greater than 5 logs of spiked virus were removed in one passage through the column. This type of approach may prove useful as a viral removal method in biopharmaceutical manufacturing. Copyright © 2001 John Wiley & Sons, Ltd.
Problem in diagnostic imaging: Mediastinal venous anomalies
Authors: Pilcher J. M. , Padhani A. R. 
Published: August 2002

AbstractThis article presents as a diagnostic problem a rare mediastinal venous anomaly detected in a patient with a primary intrathoracic tumor. Its appearance on computed tomography (CT) is discussed and compared with that of other developmental mediastinal venous anomalies. The individual CT characteristics of these anomalies and their clinical significance with respect to the management of patients with cancer are also reviewed. Clin. Anat. 14:218–226, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of the Clinical Anatomy Program in the Medical School of Porto by two cohorts of students
Authors: Tavares M.A.F. , Silva M.C. 
Published: August 2002

AbstractThe discipline of Clinical Anatomy, as introduced in the Medical School of Porto in academic year 1995/96, involved major changes in the way we teach anatomy to medical students, by adopting a clinically oriented approach. A questionnaire was designed to evaluate the opinion of second‐year medical students enrolled in the program concerning main aspects of the discipline in two consecutive years; 84% of the students returned the questionnaire in 1996/97, and 70% in 1997/98. Students were asked about the level of their approval of the organization of the discipline, the role of the teaching staff, lectures, practical sessions, educational media, and continuous and summative assessments. For items replicated in both academic years, the means of the sum of scores in each year were compared (Student's t‐distribution). Whenever a significant difference was found, changes in individual items were tested (chi‐square distribution). The evaluation of the discipline in each of the two years was highly favorable for most of the parameters analyzed. Clin. Anat. 15:56–61, 2002. © 2002 Wiley‐Liss, Inc.
Software quality and software process improvement course based on interaction with the local software industry
Authors: Jaccheri M. Letizia 
Published: August 2002

AbstractThis study describes a redesigned course in software quality and software process improvement. The course encompasses lectures and project work in groups. Part of this work project is done in collaboration with the local software industry. The proposed interaction pattern with industry is the main contribution of this work. This interaction model is based on research questions, presentations from industry, and subsequent presentations and document writing by students. Both the other related courses in software quality and process and other software engineering courses in which industry interaction is required can adopt this interaction model. The study also presents related work by surveying general industry interaction patterns and courses, which provide process and quality education. © 2002 Wiley Periodicals, Inc. Comput Appl Eng Educ 9: 265–272, 2001; Published online in Wiley InterScience (www.interscience.wiley.com.); DOI 10.1002/cae.10000
Interactive software for analysis and synthesis of passive filters and its educational applications
Authors: de Assunção Eudes Pimentel , Cardoso Renato Barreto , Afonso Guilherme , Barbosa Vladimir D. S. , Abdalla Humberto 
Published: August 2002

AbstractThis article describes an educational environment for the analysis and synthesis of passive filters in lumped parameters that combines the advantages of the multimedia tutorials with the simulation software. © 2002 Wiley Periodicals, Inc. Comput Appl Eng Educ 9: 193–207, 2001; Published online in Wiley InterScience (www.interscience.wiley.com.); DOI 10.1002/cae.10007
The young women's network: a case study in community development
Authors: Steginga S. K. , Dunn J. 
Published: August 2002

AbstractWhile young women have been found to be at additional risk for psychological morbidity after a breast cancer diagnosis, their specific needs in relation to support are not well described. A community development approach was utilized to develop the Young Women's Network, a peer support programme for young women who have been diagnosed with breast cancer that addresses their specific psychological and social needs. Central to this approach was the key role of the target group in both the definition of the problem and the generation of the solutions. This article describes the steps involved in developing this programme and guidelines for health professionals and community members who may wish to replicate either the Young Women's Network or this particular approach to programme development. Copyright © 2001 John Wiley & Sons, Ltd.
The effects of some antioxidant vitamin‐ and trace element‐supplemented diets on activities of SOD, CAT, GSH‐Px and LPO levels in chicken tissues
Authors: Öztürk‐Ürek Raziye , Bozkaya Lütfiye Arzu , Tarhan Leman 
Published: August 2002

AbstractThe effect of diets containing antioxidant vitamins and trace elements on chicken tissue activities of SOD, CAT, GSH‐Px and of LPO levels was investigated. Chickens, 45 weeks of age were divided into six groups: control group, Cu group (13.2 mg Cu kg−1 diet); Se group (0.07 mg Se kg−l diet); vitamin E group (70 mg DL‐α‐tocopherol acetate kg−1 diet) and a constant level vitamin C, 200 mg kg−1 diet); vitamin A group (240 mg retinol acetate kg−1 diet) and vitamin C group (500 mg ascorbic acid kg−1 diet).Significant variation of these antioxidant enzyme activities and LPO levels according to gender was demonstrated statistically. In the Cu group, CuZnSOD activity in the liver, erythrocyte, kidney and heart significantly increased by 75, 40, 12, 12% respectively (P<0.05). MnSOD activity in the heart, liver, kidney and brain of the vitamin C and in the heart of Cu group were found to be increased by approximately 15%, while in liver tissue of the Cu group it was reduced by 19% (P<0.05). GSH‐Px activities in the Se, vitamin E and C groups were significantly increased, conversely LPO levels decreased (P<0.001). CAT activities in the liver and heart of the vitamin C group were significantly decreased (by 32%), but in kidney tissue only that of the Cu group was increased from 30.2 ± 4.767 to 144.49 ± 6.93 U mg−1 P<0.001. The resistance to stress of the vitamin E and C groups, which had significantly increased activities of antioxidant enzymes and decreased lipid peroxide levels, were determined in 60% moisture medium at 45°C. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of vitamin A and insulin on the antioxidative state of diabetic rat heart: a comparison study with combination treatment
Authors: Zobalı Fulya , Avcı Aslıhan , Canbolat Orhan , Karasu Çimen 
Published: August 2002

AbstractBecause elevated oxidative stress may exacerbate cardiovascular complications of diabetes mellitus, the current study aimed to investigate the effects of treatment with either vitamin A, an antioxidant, or with insulin on lipid peroxidation products and antioxidant enzyme activities of diabetic rat heart. Also to evaluate whether a combination of vitamin A and insulin exerts more beneficial effects than treatment with each agent alone. Rats were made diabetic with a single injection of streptozotocin (STZ, 55 mg kg−1 i.p.). Two days after STZ‐injection, one group of diabetic rats was treated with vitamin A (retinol acetate, 30 mg kg−1 day−1 i.o.) for 12 weeks. A second group of diabetic rats was untreated for 6 weeks and then treated for another 6 weeks with insulin (8–10 IU rat−1 day−1 s.c.). Both therapies were applied to another group of diabetic rats for assessment of combined therapy with vitamin A plus insulin. Hearts from 12‐week untreated diabetic animals showed about a four‐fold increase in the level of thiobarbituric acid reactive substances (TBARS), indicative of increased lipid peroxidation. This was accompanied by approximately 100% increase in both catalase and glutathione peroxidase (GSHPx) enzyme activities. Therapy with insulin alone caused a small but significant improvement in plasma TBARS as well as GSHPx activities, but no significant change in plasma catalase in diabetic animals. Diabetes‐induced disturbance in TBARS was almost completely prevented by vitamin A therapy. Although, a similar degree of activities for GSHPx was determined in diabetic animals treated with each agent alone, combination therapy was found to be more effective than single therapies in the recovery of GSHPx of diabetic heart. In contrast to insulin single therapy, vitamin A alone significantly prevented an increase in catalase activity of diabetic heart, and a combination of these agents did not supply any further benefit. Superoxide dismutase (SOD) activity was not found significantly different among the experimental groups. STZ‐diabetes also resulted in less plasma retinol and retinol‐binding protein (RBP), which was significantly improved by insulin single therapy while vitamin A used alone, failed to increase plasma retinol and RBP levels of diabetic animals. Our findings suggest that single therapy with insulin is unable to preclude oxidative reactions in diabetic heart to the same extent as obtained by vitamin A therapy alone, in spite of allowing recovery of normal growth rate and improved vitamin A metabolism in diabetic rats. A combination of insulin with vitamin A may provide more benefits than use of either agent alone in the treatment of general characteristics of diabetes and the maintenance of antioxidant defence of diabetic heart and thus in the reduction of peroxidative stress‐induced cardiac injury. Copyright © 2001 John Wiley & Sons, Ltd.