bluuebunny/crossref_metadata_2025_split huggingface dataset:
Precursor‐Directed Biosynthesis of 6‐Deoxyerythronolide B Analogs in Streptomycescoelicolor: Understanding Precursor Effects
Authors: Leaf Timothy , Cadapan Lawrence , Carreras Christopher , Regentin Rika , Ou Sally , Woo Elaine , Ashley Gary , Licari Peter 
Published: July 2002

AbstractA fermentation process employing precursor‐directed biosynthesis is being developed for the manufacture of 6‐deoxyerythronolide B (6‐dEB) analogues. Through a plasmid‐based system in Streptomyces coelicolor, 6‐dEB synthesis is catalyzed by 6‐dEB synthase (DEBS). 6‐dEB synthesis is abolished by inactivation of the ketosynthase (KS) 1 domain of DEBS but can be restored by providing synthetic activated diketides. Because of its inherent catalytic flexibility, the KS1‐deficient DEBS is capable of utilizing unnatural diketides to form various 13‐substituted 6‐dEBs. Here we characterize process variables associated with diketide feeding in shake‐flask experiments. 13‐R‐6‐dEB production was found to depend strongly on diketide feed concentrations, on the growth phase of cultures at feeding time, and on the R‐group present in the diketide moiety. In all cases a major portion of the fed diketides was degraded by the cells.
Benzene‐Free Synthesis of Adipic Acid
Authors: Niu Wei , Draths K. M. , Frost J. W. 
Published: July 2002

AbstractStrains of Escherichia coli were constructed and evaluated that synthesized cis,cis‐muconic acid from d‐glucose under fed‐batch fermentor conditions. Chemical hydrogenation of the cis, cis‐muconic acid in the resulting fermentation broth has also been examined. Biocatalytic synthesis of adipic acid from glucose eliminates two environmental concerns characteristic of industrial adipic acid manufacture: use of carcinogenic benzene and benzene‐derived chemicals as feedstocks and generation of nitrous oxide as a byproduct of a nitric acid catalyzed oxidation. While alternative catalytic syntheses that eliminate the use of nitric acid have been developed, most continue to rely on petroleum‐derived benzene as the ultimate feedstock. In this study, E. coli WN1/pWN2.248 was developed that synthesized 36.8 g/L of cis, cis‐muconic acid in 22% (mol/mol) yield from glucose after 48 h of culturing under fed‐batch fermentor conditions. Optimization of microbial cis,cis‐muconic acid synthesis required expression of three enzymes not typically found in E. coli. Two copies of the Klebsiella pneumoniae aroZ gene encoding DHS dehydratase were inserted into the E. coli chromosome, while the K. pneumoniae aroY gene encoding PCA decarboxylase and the Acinetobacter calcoaceticus catA gene encoding catechol 1,2‐dioxygenase were expressed from an extrachromosomal plasmid. After fed‐batch culturing of WN1/pWN2.248 was complete, the cells were removed from the broth, which was treated with activated charcoal and subsequently filtered to remove soluble protein. Hydrogenation of the resulting solution with 10% Pt on carbon (5% mol/mol) at 3400 kPa of H2 pressure for 2.5 h at ambient temperature afforded a 97% (mol/mol) conversion of cis, cis‐muconic acid into adipic acid.
High‐Level Expression of a Heterologous Gene in Escherichia coli in Response to Carbon‐Nitrogen Source and C/N Ratio in a Batch Bioreactor
Authors: Bhattacharya Sanjoy K. , Dubey Ashok K. 
Published: July 2002

AbstractOverexpression of the target gene in a recombinant strain of Escherichia coli has been analyzed in view of changes in the carbon−nitrogen source and as a function of C/N ratio. The rate of target gene expression varied over a range of 200%, and the yield coefficient for the target gene product changed over 400% with change in carbon source at 10 g L−1 in M9 medium. With variation in nitrogen source, however, only marginal changes (10–15%) occurred in these parameters of overexpression. Higher concentration, for example 2.5 g L−1, of any nitrogen source adversely affected heterologous expression as rate of target gene expression declined in the range 35%−50% and the yield coefficient of foreign protein decreased between 45% and 60%. A C/N ratio of 15 was found to be optimum for both parameters for overexpression and host specific parameters such as specific growth rate and observed yield coefficient for cellular growth. An analysis with respect to temperature and pH revealed that host and expression parameters were quite susceptible to changes in these factors.
Factors Influencing Parathion Degradation by Recombinant Escherichiacoli with Surface‐Expressed Organophosphorus Hydrolase
Authors: Kaneva Irina , Mulchandani Ashok , Chen Wilfred 
Published: July 2002

AbstractA unique approach for organophosphorus pesticides detoxification was developed previously by anchoring organophosphorus hydrolase (OPH) onto the surface of Escherichia coli with a tightly regulated tac promoter. The resulting recombinant cells degraded parathion very effectively without the diffusional limitation observed in cells expressing OPH intracellularly. However, the precise conditions for surface targeting or pesticide degradation were not fully understood. In this paper, several factors influencing parathion degradation were investigated. Production of active OPH onto the cell surface was highly host‐specific; a high rate of parathion degradation was observed from strains JM105 and XL1‐Blue, which regulated production of the OPH fusion very tightly. However, in the absence of ampicillin selection, plasmids were only favorably maintained in strain XL1‐Blue. OPH activity was highly dependent on growth conditions. Optimal OPH activity was observed when cells were grown in Luria−Bertani (LB) ‐buffered medium at 37 °C. OPH activity was further improved by supplementing the growth medium with cobalt chloride, which favors the formation of the metal active center. The timing of cobalt addition also influenced parathion degradation. Maximum OPH activity was obtained by adding cobalt to induced cultures during the late stationary phase. The resulting cultures grown under the optimized conditions had an eight‐fold increase in parathion degradation.
Effect of Resin Characteristics on Fluidized Bed Adsorption of Proteins
Authors: Wright Pamela R. , Muzzio Fernando J. , Glasser Benjamin J. 
Published: July 2002

AbstractDespite numerous advantages, fluidized bed adsorption is limited in commercial applications due to a poor understanding of the relationships between mass transfer, hydrodynamics, and adsorption. To obtain a better understanding of these parameters, we used two commercially available resins to compare the adsorption of lysozyme as a function of bed expansion and bulk‐phase viscosity using frontal analysis. Under static conditions adsorption was well represented by a Langmuir isotherm. Dynamic capacities at breakthrough were measured and normalized relative to the equilibrium capacity of each resin to facilitate direct comparison of resin performance under each condition. To quantify the impact of resin characteristics in expanded bed adsorption, we carried out a comparison of mass‐transfer effects using a macroporous resin, Streamline SP, and a hyper‐diffusive resin, S‐HyperD LS. Both resins are designed for fluidized bed adsorption of proteins. In this study the results of frontal analysis showed that breakthrough was due to mass‐transfer limitations of the adsorbing particles at expansions of 2 times the settled bed height. At expansions of 3 and 4 times the settled bed height, axial dispersion increased significantly; however mass‐transfer limitations were still the dominant mechanistic feature contributing to early breakthrough at reduced dynamic capacity. Adsorption capacity under all conditions in this study was poorer for the macroporous resin than for the hyper‐diffusive resin due to intraparticle mass‐transfer limitations.
A comparison of the characteristics of circulating anti-myeloperoxidase autoantibodies in vasculitis with those in non-vasculitic conditions
Authors: LOCKE I C , LEAKER B , CAMBRIDGE G 
Published: July 2002

SUMMARYAlthough circulating anti-neutrophil cytoplasmic antibodies (ANCA) specific for myeloperoxidase (MPO) are strongly associated with the presence of vasculitis, they have been described in sera from patients with other conditions. High levels of anti-MPO antibodies can also persist in sera from patients with vasculitis despite the achievement of clinical remission. One possible interpretation is that a potentially pathogenic subset of anti-MPO antibodies exists, which is only present in patients with active vasculitis. We therefore compared the characteristics of anti-MPO antibodies in sera from patients with active vasculitis (n = 18) with those present in remission (n = 9) and in a disease control group (n = 10) without clinical evidence of vasculitis. The class, subclass and ability of anti-MPO antibodies from the three groups of patients to recognize three different conformational epitopes were analysed using ELISA-based techniques. The expression of an idiotope, designated 9G4, was also examined. Epitope recognition by anti-MPO antibodies from all patients tested was found to be similar. Sera from patients with active vasculitis showed an over-representation of IgG4 subclass anti-MPO antibodies and a more frequent presence of IgM class anti-MPO antibodies. In disease controls, IgG1 anti-MPO antibodies were predominant. In vitro, neutrophil activation by ANCA has been shown to be dependent on engagement of neutrophil FcγRIIa receptors following binding of these autoantibodies to surface-expressed ANCA antigens. We found that active vasculitis may be associated with the presence of circulating anti-MPO antibodies which do not significantly bind this receptor, suggesting that mechanisms other than those dependent on FcγRIIa binding should be explored. In addition, the expression of the 9G4 idiotope on anti-MPO antibodies in 60% (12/18) of patients with active vasculitis and 20% (2/10) of disease control patients may indicate a common origin for anti-MPO antibodies in different individuals.
Clinical efficacy of a new 30‐min algorithm for transurethral microwave thermotherapy: initial results
Authors: De La Rosette J.J.M.C.H. , Francisca E.A.E. , Kortmann B.B.M. , Floratos D.L. , Debruyne F.M.J. , Kiemeney L.A.L.M. 
Published: July 2002

Objective To assess the efficacy of a new 30‐min algorithm for high‐energy transurethral microwave thermotherapy (TUMT, Prostasoft 3.5) in the treatment of men with lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia. Patients and methods A total of 108 men (mean age 66 years) with bothersome LUTS were treated with the new TUMT protocol. All patients were evaluated using a standard assessment at baseline, 6, 12, 26 and 52 weeks after TUMT. The evaluation included the assessment of objective and subjective outcome measures, with a urodynamic evaluation using pressure‐flow analysis, and the occurrence of adverse events. Results The treatment was well tolerated. In general, the International Prostate Symptom Score improved from a mean of 20.0 at baseline to a mean of 9.3 at 6 months after treatment. The maximum urinary flow improved from 9.4 mL/s to 14.6 mL/s at 6 months. The mean duration of catheterization was 17.9 days. The urodynamic evaluation showed a change from the obstructed to the equivocal zone on the Abrams–Griffith nomogram. There were no serious complications. Urgency and frequency were the most frequent side‐effects after treatment; these all resolved within 3 months. Conclusion High‐energy TUMT using the new high‐dose Prostasoft 3.5 protocol appears to be a safe and effective treatment. The faster procedure improves the tolerance of the treatment. The subjective and objective improvements were significant and the treatment‐related morbidity low. A longer follow‐up is needed to assess the durability of this new treatment protocol.
Non‐reassuring fetal status in the prolonged pregnancy: the impact of fetal weight
Authors: Sylvestre G. , Fisher M. , Westgren M. , Divon M. Y. 
Published: July 2002

AbstractObjectiveTo evaluate the incidence of abnormal fetal findings and Cesarean delivery for non‐reassuring fetal status as a function of birth weight in the uncomplicated prolonged pregnancy.MethodsSeven hundred and ninety‐two patients at or beyond 41 weeks' gestation were managed expectantly. Population‐specific birth‐weight percentiles were calculated. Fetuses were retrospectively categorized as small (birth weight < 10th percentile), average (10th percentile ≤ birth weight ≤ 90th percentile) or large (birth weight > 90th percentile). The incidences of abnormal antepartum fetal testing results (i.e. oligohydramnios and/or abnormal non‐stress testing) and Cesarean delivery for intrapartum non‐reassuring fetal status were calculated for these three birth‐weight categories.ResultsThere was a significant inverse relationship between the incidence of abnormal fetal testing and birth‐weight category (36%, 14% and 9% for small, average and large fetuses, respectively, P < 0.001). Small fetuses were more likely to require a Cesarean delivery for non‐reassuring fetal status during labor than were all other fetuses (12.3% vs. 5.3%, P = 0.024).ConclusionsThe frequency of oligohydramnios and abnormal non‐stress testing is inversely related to birth weight in the expectantly managed prolonged pregnancy. In addition, small fetuses born at or beyond 41 weeks' gestation have an increased rate of Cesarean delivery for intrapartum non‐reassuring fetal status. Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecology
Isogyre formation by isotropic refracting bodies
Authors: Lekner J. 
Published: July 2002

SummaryA simple derivation is given of a formula for the intensity pattern produced by a diffusely illuminated lens‐like body held between a polarizer and an analyser. The formula generalizes the results of Charman and of Pierscionek and Chan for a dielectric sphere between crossed polaroids. A dark cross is universal for all lens‐like bodies whose axis of symmetry is normal to the polarizer and analyser. Intensity contours are plotted for ellipsoidal lenses.
Eye drops and contact lenses‐‐is there a problem?
Authors: Rubinstein M. P. , Evans J. E. 
Published: July 2002

Preservatives used in topical ophthalmic preparations can result in a wide variety of toxicity or hypersensitivity reactions involving the anterior segment of the eye. The use of eyedrops in patients wearing contact lenses is therefore a contentious issue.In one of the major contemporary contact lens texts advice is both confusing and contradictory. The British National Formularly and Monthly Index of Medical Specialities advise discontinuation of contact lens wear (particularly soft lenses) when using preserved ophthalmic preparations. Unpreserved drops are suggested as a safer alternative. There appears to be less concern regarding wearers of gas permeable lenses.This issue is of particular importance in medical contact lens practice were therapeutic lenses are widely used, often for extended periods and often in conjunction with topical medical therapy. In these circumstances, unpreserved drops are frequently described, at considerably greater cost than their preserved equivalent.A review of the literature indicates that this perceived problem has been greatly overstated. This may stem from previous studies of contact lens interactions with care solutions.This poster will present a review of the subject.
Recurrence After a First Untreated Seizure in the Hong Kong Chinese Population
Authors: Hui A. C. F. , Tang A. , Wong K. S. , Mok V. , Kay R. 
Published: July 2002

Summary:  Purpose: There is wide variation in the reported prognosis after a first unprovoked generalized tonic‐clonic convulsion and in the risk factors that are associated with recurrence. Estimates for the risk of recurrence range from 26 to 71%. We investigated the likelihood of a second attack in Hong Kong Chinese patients.Methods: One hundred thirty‐two patients with a first convulsion that was unexplained by acute neurological or medical causes were retrospectively ascertained. Patients' demographic details, potential risk factors for recurrence, and current seizure status were recorded. Survival analysis was performed using the Kaplan‐Meier procedure.Results: The cumulative probability of a second attack at 1, 2, 3, and 4 years was 30, 37, 42, and 47%, respectively. Seizures in patients with abnormal computer tomography scans of the brain were associated with an increased risk of recurrence on multivariate analysis.Conclusions: Thirty percent of the sample population experienced a second seizure after 1 year. An additional 17% continue to be at risk of a second convulsion during the next 3 years.
Longitudinal Changes in Body Mass Index and Body Composition over 3 Years and Relationship to Health Outcomes in Hong Kong Chinese Age 70 and Older
Authors: Woo Jean , Ho Suzanne C. , Sham Aprille 
Published: July 2002

OBJECTIVES: To determine longitudinal changes in body mass index (BMI) and body composition with age and the relationship between these changes with mortality, morbidity, functional capacity, and other health outcome measures.DESIGN: A 3‐year longitudinal study of a random sample of community‐living subjects.SETTING: Older Chinese in the Hong Kong Special Administrative Region of China.PARTICIPANTS: Two thousand and thirty‐two Chinese subjects age 70 and older recruited territory‐wide by proportional random sampling.MEASUREMENTS: Baseline information collected included medical history, self‐perceived health, Barthel Index, Geriatric Depression Score, time taken to complete a 16‐foot walk, height, weight, mid‐arm circumference, arm skin‐fold thickness, and waist/hip ratio. Body composition was calculated from prediction equation. Outcome measures included mortality, development of new diseases, Barthel Index, time taken for 16‐foot walk, self‐perceived health, and Geriatric Depression Score.RESULTS: All parameters, with the exception of triceps skin‐fold thickness in men, decreased, regardless of presence or absence of disease. The decrease in arm circumference, triceps skin‐fold thickness, and total body fat (TBF) was greater in women than in men, whereas men had a greater decrease in fat‐free mass (FFM). Even in the absence of disease, three times as many subjects lost ≥5kg in weight as gained ≥5kg (15% vs 5%), and only age could be identified as a contributing factor to this weight loss. In the absence of disease, lower anthropometric indices were associated with greater mortality, development of new disease (in women only), dependency, and poor performance measure. Waist‐hip ratio was not associated with mortality or any other health outcomes. Decrease in both FFM and TBF were associated with worse outcomes, the effect being more marked in women.CONCLUSION: In the older population, changes in weight and body composition occur even in the absence of disease and are associated with mortality and physical functioning level. Weight loss rather than weight gain appears to be more important in this population, and promotion of life‐style interventions targeted at weight maintenance would be important.
Exercise-induced neurocardiogenic syncope
Authors: Kosinski D. , Grubb B.P. , Karas B.J. , Frederick S. 
Published: July 2002

Abstract
The evaluation of syncope occurring during exercise or occurring spontaneously in highly trained individuals presents a unique diagnostic challenge. It is of critical importance to exclude potential life-threatening disorders such as hypertrophic cardiomyopathy, long QT syndrome, right ventricular dysplasia, anomalous coronary artery distribution, valvular heart disease, myocarditis, or exercise-induced arrhythmia. This review is not directed towards identifying, treating, or determining athletic eligibility of individuals with such disorders. Rather, we endeavour to discuss the pathophysiology of exercise-induced neurocardiogenic syncope and to address the role of head upright tilt testing in evaluating syncope in athletic individuals in whom proper evaluation has excluded the presence of ischaemic heart disease or primary structural or electrical heart disease.
Effects of corrugation parameters on fluid mixing characteristics in corrugated passages
Authors: Gaiser Gerd , Kottke Volker 
Published: July 2002

Static mixers are well established in process engineering. Their particular advantages are in-line mixing, no moving parts, low power consumption, and simultaneous homogenization of residence time behavior. Several species of static mixers are well known. An example of their arrangement is based on corrugated passages formed by layers of single plates with opposing orientation. Until now, the corrugation parameters of this species have mainly been designed according to few experimental studies. However, flow phenomena, implied by the geometry of the corrugated structure, are of significant influence on the mixing behavior, the pressure drop, and the residence time characteristics in corrugated passages. In new investigations, the effects of a variety of corrugation parameters on flow phenomena, mixing characteristics/and pressure drop have been systematically determined. The results prove that there are quite different kinds of flow phenomena depending on the geometrical parameters of the structure. Some parameter combinations lead to no mixing at all, others lead to a homogeneous mixing within a small length. Examples are shown of flow behavior in corrugated passages; here the flow has been traced locally making the flow direction evident.
The effects of corrugation parameters on the fundamental flow phenomena will be discussed. In order to describe and predict the flow behavior in these corrugated passages, a model has been set up based on the fundamental flow phenomena. This model allows the simulation of flow behavior in corrugated passages, thereby allowing, also, the simulation of the mixing characteristics and the residence time behavior of the fluid in these structures. Examples of the simulation, where the local addition of a tracer and its mixing across the structure has been simulated, are shown. Further results of flow simulation on mixing characteristics and dynamic aspects will be compared to experiments. Combined with the pressure drop in corrugated passages, the model allows the optimization of motionless mixer design. Several aspects of structure optimization will be discussed.
Naltrexone in the treatment of heroin dependence: a literature review
Authors: TUCKER THAMIZAN K , RITTER ALISON J. 
Published: July 2002

AbstractNaltrexone is an opioid antagonist which binds competitively at the opioid receptors and blocks the effects of exogenous opioids. Naltrexone has been used to facilitate withdrawal (in using rapid and ultra rapid withdrawal techniques). The research on the efficacy of rapid and ultra‐rapid withdrawal to date is extremely limited. The predominant use of naltrexone is as a post‐withdrawal relapse prevention intervention. Research has revealed that naltrexone's acceptability is generally poor, mainly appealing to those highly motivated towards achieving and maintaining abstinence. In spite of poor acceptibility, naltrexone‐treated participants often produce lower levels of craving for opiates, significantly higher rates and longer periods of abstinence and significantly greater improvement in psychosocial functioning than those treated with placebos and standard treatment programmes. The studies of highly motivated participants demonstrated the highest retention and completion rates. Being employed and having good social support have been identified as being associated with successful outcome. There also appears to be a trend towards greater success being associated with older participants, and those with a greater number of previous treatment attempts. The combined use of naltrexone and psychosocial therapy has proved to be more effective than psychosocial therapy alone, and more effective than naltrexone treatment alone, in improving post treatment outcome. Future research directions are summarized.