bluuebunny/crossref_metadata_2025 huggingface dataset:
Curing of crust leather by ultraviolet radiation with urethane acrylate: Role of pigment
Authors: Khan Mubarak A. , Rahman M. Mizanur , Bhuyan M. Z. R. , Ahmad M. U.
Published: October 2002

Eight different formulations were developed with four diacrylate reactive monomers such as tripropylene glycol diacrylate (TPGDA), 1,4‐butanediol diacrylate (BDDA), 1,6‐hexanediol diacrylate (HDDA), and 2‐ethylene glycol dimethacrylate (EGDMA) and aromatic urethane diacrylate (M1100) in order to modify the crust leather surface. To study the effect of pigment on the performance of ultraviolet (UV)‐cured leather surface, 1% pigment (congored) was incorporated in the formulations. Irgacure 369 (2%) was also used in the formulation as photoinitiator. The gel content, tensile strength, elongation at break, and pendulum hardness of UV‐cured thin films with and without pigment was studied. The films without pigment produced better properties. Among all the diluents, BDDA‐containing films showed the best performance. Different properties of UV‐coated leather surface such as pendulum hardness, tensile strength, elongation, gloss (at 20° and 60°), adhesion, and abrasion were studied. Effect of gloss on simulating weathering was also performed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 692–697, 2002
Mechanical properties and morphology of poly(ethylene glycol)‐side‐chain‐modified bismaleimide polymer
Authors: Chian K. S. , Du X. Y. , Goy H. A. , Feng J. L. , Yi S. , Yue C. Y.
Published: October 2002

Two maleimido‐end‐capped poly(ethylene glycol) (m‐PEG)‐modified bismaleimide (BMI) resins [4,4′‐bismaleimido diphenylmethane (BDM)] were synthesized from poly(ethylene glycol) (PEG) of two different molecular weights. A series of m‐PEGs and unmodified BDM were blended and thermally cured. The effect of incorporating m‐PEG side chains on the morphology and mechanical behaviors of BMI polymer were evaluated. The mechanical properties of these m‐PEG‐modified BMIs that were evaluated included flexural modulus, flexural strength, strain at break, fracture toughness, and fracture energy. The morphology of these blends was studied with scanning electron microscopy. All the m‐PEG‐modified BMI polymers showed various degrees of phase separation depending on the molecular weights and concentrations of the m‐PEG used. The effects of these morphological changes in the m‐PEG‐modified BMI polymers were reflected by the improved fracture toughness and strain at break. However, there was a reduction in the flexural moduli in all m‐PEG‐modified BMI polymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 715–724, 2002
Cloning and characterization of Acmar1, a mariner‐like element in the asiatic honey bee, Apis cerana japonica (Hymenoptera, Apocrita)
Authors: Sumitani Megumi , Lee Jae Min , Hatakeyama Masatsugu , Oishi Kugao
Published: October 2002

A mariner‐like element was cloned from the genome of the Asiatic honey bee, Apis cerana japonica (Hymenoptera, Apocrita). The (composite) clone, named Acmar1, was 1,378 bp long, and encoded 336 amino acids corresponding to a transposase‐like putative polypeptide in a single open reading frame. The D,D(34)D motif, the catalytic domain of the mariner transposase, was present, although there was a deletion of five amino acid residues within it as compared with the active transposase in Drosophila mauritiana. Nineteen‐bp‐long imperfect inverted terminal repeat‐like sequences flanked by TA dinucleotides, the typical target site for mariner insertion, were observed. Southern blot analysis using a fragment covering two‐thirds of the Acmar1 transposase coding sequence as a probe indicated the presence of multiple Acmar1‐like elements in the genome. Maximum‐parsimony phylogenetic analysis based on the transposase amino acid sequences of insect mariner‐like elements revealed that Acmar1 is a member of the mellifera subfamily. Arch. Insect Biochem. Physiol. 50:183–190, 2002. © 2002 Wiley‐Liss, Inc.
Purification and characterization of acetylcholinesterase from cotton aphid (Aphis gossypii Glover)
Authors: Li Fei , Han Zhaojun
Published: October 2002

A simple and effective method was set up to purify acetylcholinesterase (AChE, EC3.1.1.7) from the cotton aphid, Aphis gossypii Glover. The procedure involved filtration on a sephadex G‐25 column, separation with sephadex G‐200 and procainamide affinity column. AChE from both susceptible and resistant strains were purified to a single band as resolved on denaturing polyacrylamide gel electrophoresis (SDS‐PAGE). The specific activity increased by 35,100‐ and 33,680‐fold with a yield of 30.3 and 29.8%, respectively. The molecular mass of the purified AChE was about 63,500 Dalton as determined by SDS‐PAGE. However, three bands resolved on PAGE gel electrophoresis, leading to the inference that native AChE exists in three forms. The optimum conditions for measuring the activity of purified AChE with kinetic method were 0.02M phosphate buffer, pH7.2, 0.02 mM 5,5′‐dithiobis‐(2‐nitrobenzoic acid) (DTNB), and 25°C. Investigation also revealed that crude extract and purified AChE had different kinetic characteristics and inhibitory properties. They responded differently to varied DTNB, ATChI, and phosphate buffer ion concentrations, as well as pH, temperature, and inhibitors. The purified AChE was more sensitive to eserine, methamidophos, and pirimicarb. Especially for resistant aphids, the sensitivity of purified AChE to methamidophos and pirimicarb was enhanced 6.43 and 11.73 times, respectively. We infer that one or more factors in the crude extract from the resistance strain have more influence on AChE sensitivity. Further study is needed to investigate the basis of these observations. Arch. Insect Biochem. Physiol. 51:37–45, 2002. © 2002 Wiley‐Liss, Inc.
Eicosanoids mediate Manduca sexta cellular response to the fungal pathogen Beauveria bassiana: A role for the lipoxygenase pathway
Authors: Lord, Jeffrey C. , Anderson Sheri , Stanley David W.
Published: October 2002

Many studies have documented the involvement of eicosanoids in insect cellular immune responses to bacteria. The use of the fungal pathogen Beauveria bassiana as a nodulation elicitor, with inhibition of phospholipase A2 by dexamethasone, extends the principle to fungi. This study also provides the first evidence of involvement of the lipoxygenase (LOX) pathway rather than the cyclooxygenase (COX) pathway in synthesis of the nodulation mediating eicosanoid(s). The LOX product, 5(S)‐hydroperoxyeicosa‐6E,8Z,11Z,14Z‐tetraenoic acid (5‐HPETE), substantially reversed nodulation inhibition caused by dexamethasone and the LOX inhibitors, caffeic acid and esculetin. The COX product, prostaglandin H2 (PGH2), did not reverse the nodulation inhibition by dexamethasone or the COX inhibitor, ibuprofen. None of the inhibitors tested had a significant effect on the phagocytosis of B. bassiana blastospores in vitro. Hemocyte phenoloxidase activity was reduced by dexamethasone, esculetin, and the COX inhibitor, indomethacin. The rescue candidates 5‐HPETE and PGH2 did not reverse the inhibition. Arch. Insect Biochem. Physiol. 51:46–54, 2002. Published 2002 Wiley‐Liss, Inc.
Tumor necrosis factor α‐mediated joint destruction is inhibited by targeting osteoclasts with osteoprotegerin
Authors: Redlich Kurt , Hayer Silvia , Maier Andrea , Dunstan Colin R. , Tohidast‐Akrad Makiyeh , Lang Susanne , Türk Birgit , Pietschmann Peter , Woloszczuk Wolfgang , Haralambous Silva , Kollias George , Steiner Günter , Smolen Josef S. , Schett Georg
Published: October 2002

Objective

To study the effects of osteoclast‐targeted therapies, such as osteoprotegerin (OPG) and pamidronate, on joint inflammation and bone destruction using a tumor necrosis factor α (TNFα)‐transgenic mouse model.

Methods

Mice were placed into 5 groups that received either OPG, pamidronate, a combination of both agents, infliximab as a positive control, or phosphate buffered saline as a negative control. Treatment was initiated at the onset of arthritis, continued over 6 weeks, and thereafter, the clinical, radiologic, and histologic outcomes were assessed.

Results

A significant improvement in clinical symptoms, as assessed by the reduction of paw swelling, was only found in the infliximab group, whereas all other treatment groups failed to show significant improvement. However, when assessing structural damage with radiographic analysis, a significant retardation of joint damage was evident in animals treated with OPG (55% reduction of erosions), pamidronate (50% reduction of erosions) the combination therapy of OPG and pamidronate (64% reduction of erosions), and with infliximab (66% reduction of erosions). Confirming these data, quantitative histologic analysis revealed a significant reduction in the size of bone erosions in all treatment groups (OPG 56%, pamidronate 53%, OPG and pamidronate 81%, and infliximab 46%) compared with the control group. Furthermore, a significant reduction of osteoclast numbers was seen in animals treated with OPG alone or in combination with pamidronate as well as in animals treated with infliximab.

Conclusion

These data suggest that OPG alone or in combination with bisphosphonates is an effective therapeutic tool for the prevention of TNFα‐mediated destruction of bone by reducing the number of bone‐resorbing cells in the inflammatory tissue.
Takayasu arteritis: Utility and limitations of magnetic resonance imaging in diagnosis and treatment
Authors: Tso Elisa , Flamm Scott D. , White Richard D. , Schvartzman Paulo R. , Mascha Edward , Hoffman Gary S.
Published: October 2002

Objective

Previous studies have confirmed the poor correlation of symptoms, signs, and levels of acute‐phase reactants with disease activity in ∼50% of all patients with Takayasu arteritis (TA). Invasive angiographic studies demonstrate vessel lumen anatomy, but do not provide qualitative information about the vessel wall. Moreover, sequential invasive angiographic studies expose patients to high‐dose ionizing radiation and catheter/procedure‐related morbidity. The aim of the present study was to determine the utility of new developments in vascular magnetic resonance (MR) technology in patients with TA.

Methods

Electrocardiogram‐gated “edema‐weighted” MR was used to evaluate the aorta and its primary branches with regard to the vascular lumen, vessel wall anatomy, and vessel wall edema in 24 TA patients (77 studies). Inclusion criteria were age <50 years and features of TA on both clinical examination and invasive angiographic studies. Patients were stratified based on clinical and laboratory indications of having either unequivocally active disease, inactive disease, or uncertain disease status.

Results

MR revealed vessel wall edema in 94% (17 of 18), 81% (13 of 16), and 56% (24 of 43) of studies obtained during periods of unequivocally active disease, uncertain disease activity, and apparent clinical remission, respectively. Westergren erythrocyte sedimentation rate and C‐reactive protein values did not correlate with either the clinical assessment of disease activity or MR evidence of vascular edema. The frequency of presumed vascular inflammation (edema), as assessed by MR, in patients who appeared to be in remission was similar to the reported frequency of new angiographic lesions and histopathologic evidence of active disease in surgical specimens from patients thought to be in remission. However, the presence of edema within vessel walls did not consistently correlate with the occurrence of new anatomic changes found on subsequent studies.

Conclusion

Inconsistencies in the presence or absence of vessel edema and subsequent anatomic changes have cast doubt on the utility of edema‐weighted MR imaging as a sole guide to disease activity and treatment in TA. In this study, the greatest utility of MR was in providing a safe, noninvasive means of assessing changes in vascular anatomy.
Association of the interleukin‐1 gene cluster on chromosome 2q13 with knee osteoarthritis
Authors: Loughlin John , Dowling Barbara , Mustafa Zehra , Chapman Kay
Published: October 2002

Objective

To investigate whether the interleukin‐1 (IL‐1) ligand gene cluster at 2q13 encodes for genetic susceptibility to primary osteoarthritis (OA).

Methods

Seven single‐nucleotide polymorphisms (SNPs) and a variable‐number tandem repeat (VNTR) polymorphism from within the IL‐1 ligand genes IL1A, IL1B, and IL1RN were genotyped in a cohort of 557 OA cases and 557 age‐matched controls.

Results

None of the variants demonstrated association in the unstratified data set. However, when cases were stratified according to sex and site of disease (hip or knee), 4 SNPs showed marginal evidence for association (P < 0.1) in knee cases (n = 136) and male knee cases (n = 58). For 2 of these SNPs, evidence for association was enhanced when probands from 60 knee‐only affected sibling pair families were genotyped and combined with the original knee cases (P ≤ 0.05). Further analysis revealed that the associated alleles at 2 of these SNPs were markers for the same haplotype, the frequency of which was significantly elevated when knee cases and knee probands were combined (P = 0.01, odds ratio [OR] 1.4) and when male knee cases and male knee probands were combined (P = 0.009, OR 1.7). Furthermore, linkage analysis of 2q revealed suggestive evidence for linkage to the IL‐1 gene clusters in affected sibling pairs concordant for knee OA but no evidence for linkage in affected sibling pairs concordant for hip OA.

Conclusion

The IL‐1 ligand cluster encodes for susceptibility to knee OA but not to hip OA, highlighting the genetic heterogeneity of this common, complex disease.
Small nerve fiber involvement in systemic lupus erythematosus: A controlled study
Authors: Omdal Roald , Mellgren Svein Ivar , Gøransson Lasse , Skjesol Astrid , Lindal Sigurd , Koldingsnes Wenche , Husby Gunnar
Published: October 2002

Objective

To determine if patients with systemic lupus erythematosus (SLE) may have a peripheral neuropathy involving unmyelinated and small, myelinated nerve fibers, by immunostaining epidermal nerve fibers (ENF) in skin biopsy samples for the panaxonal marker, protein gene product 9.5 (PGP 9.5).

Methods

Fifteen consecutive and nonselected SLE patients and 15 age‐ and sex‐matched controls were included in the study. The age of the patients ranged from 25 years to 65 years, with a mean ± SD age of 47.3 ± 10.2 years and a disease duration of 2–28 years (mean ± SD 14.8 ± 8.6 years). Two 3‐mm skin biopsy samples were obtained with a punch needle ∼10 cm superior to the lateral malleolus of the right leg and immunostained with 0.1% rabbit polyclonal antibodies to human PGP 9.5. The number of ENF per millimeter was counted and recorded as the mean ± SD of counts in six 50‐μm sections, 3 from each of the 2 biopsy samples.

Results

The mean number of ENF per mm in patients with SLE was 8.0 ± 1.5 (range 5.0–9.9), while the matched controls had 12.2 ± 3.8 ENF per mm (range 6.8–18.6) (P = 0.0006).

Conclusion

This study indicates that a small fiber involvement in patients with SLE may be responsible for the prevalent neuropathic symptoms and impaired warm sense that is observed in such patients.
The genetic contribution to carpal tunnel syndrome in women: A twin study
Authors: Hakim Alan J. , Cherkas Lynn , El Zayat Sameh , MacGregor Alexander J. , Spector Tim D.
Published: October 2002

Objective

To assess the relative genetic and environmental contribution to carpal tunnel syndrome (CTS) using a classic twin study of monozygotic (MZ) and dizygotic (DZ) twins.

Methods

The study group comprised unselected female twin pairs, between 20 and 80 years of age, from the St Thomas' UK Adult Twin Registry. Individuals completed a questionnaire that included details on potential risk factors for CTS. The diagnosis of CTS was made using a standardized hand pain diagram and validated criteria. The genetic contribution to CTS was assessed using variance component and regression methods, the heritability was adjusted for environmental confounders. The role of individual risk factors was assessed by a nested case‐control study.

Results

An overall prevalence of 14.2% for CTS was found in a population of 4,488 females, comprising 867 MZ and 970 DZ twin pairs, and 814 singletons. The concordance for CTS was significantly higher in MZ compared with DZ twins (case‐wise concordance values of 0.35 and 0.24 respectively, with a significantly increased MZ:DZ ratio of 1.48; P = 0.03). Modeling produced a heritability estimate of 0.46 (95% CI 0.34–0.58) that was essentially unchanged after adjustment for environmental risk factors including age, body mass index, physical activities, and hormonal/reproductive factors. No major influence of any individual risk factor was seen in the case‐control analysis of 520 cases and 3,154 controls, apart from a modest association with menopausal status with an increased risk of 1.53 and 1.43 in the peri and postmenopausal groups. There was no overall effect of age or body mass index.

Conclusion

This is the first study to explore the genetic component of CTS. Our data show that up to half of the liability to CTS in women is genetically determined, and this appears to be the single strongest risk factor, with only minor contributions from known environmental factors. Further studies should focus on genetic mechanisms that may lead to tests for susceptibility and detection of those at risk of developing CTS.
The enlarging clinical, genetic, and population spectrum of tumor necrosis factor receptor–associated periodic syndrome
Authors: Dodé Catherine , André Marc , Bienvenu Thierry , Hausfater Pierre , Pêcheux Christophe , Bienvenu Jacques , Lecron Jean‐Claude , Reinert Philippe , Cattan Daniel , Piette Jean‐Charles , Szajnert Marie‐France , Delpech Marc , Grateau Gilles ,   French Hereditary Recurrent Inflammatory Disorder Study Group
Published: October 2002

Objective

To characterize the frequency, clinical signs, and genotypic features of tumor necrosis factor receptor–associated periodic syndrome (TRAPS) in a series of 394 patients of various ethnic origins who have recurrent inflammatory syndromes.

Methods

Sequencing of the coding region of the TNFRSF1A gene was performed in 128 patients in whom there was a high suspicion of TRAPS, and denatured high‐performance liquid chromatography was used to systematically screen for TNFRSF1A in 266 patients with recurrent inflammatory syndrome and no or only 1 Mediterranean fever gene (MEFV) mutation.

Results

TNFRSF1A mutations were found in 28 (7.1%) of 394 unrelated patients. Nine (32%) of the 28 patients had a family history of recurrent inflammatory syndromes. In 13 patients, the length of the attack of inflammation was fewer than 5 days. Three of the mutations (Y20H, L67P, and C96Y) were novel. Two mutations, R92Q and (mainly) P46L, found in 12 and 10 patients, respectively, had lower penetrance compared with other mutations. TNFRSF1A mutations were found in patients of various ethnic origins, including those at risk for familial Mediterranean fever (FMF): Armenians, Sephardic Jews, and especially Arabs from Maghreb. Only 3 (10.7%) of the 28 patients had amyloidosis.

Conclusion

TRAPS is an underdiagnosed cause of recurrent inflammatory syndrome. Its presence in the population of persons of Mediterranean ancestry and the short duration of the attacks of inflammation can lead to a fallacious diagnosis of FMF. Because an accurate diagnosis in patients with recurrent inflammatory syndromes is crucial for proper clinical management and treatment, genetic screening for TNFRSF1A is warranted.
Factors of importance for work disability in women with fibromyalgia: An interview study
Authors: Liedberg Gunilla M. , Henriksson Chris M.
Published: October 2002

Objective

Fibromyalgia symptoms such as continuous pain, tiredness, hyperalgesia, and allodynia limit gainful employment. The present study examines which factors influence the decision to remain in a work role for women with fibromyalgia. This information is important for the individual and for public finances.

Methods

Qualitative interviews were performed with 39 women, 19 of whom were gainfully employed and 20 who had stopped working. The transcribed interviews were analyzed and divided into categories and subcategories.

Results

Four categories appear, at societal and individual levels, that were regarded as important by the women for remaining in a work role.

Conclusions

The ability to remain at work depends not only on limitations in work capacity, but also on the capacity of society to adjust work environments and work tasks. More individual solutions are needed to allow women with fibromyalgia to maintain work roles.
Immunosuppressive therapy in lupus nephritis: The Euro‐Lupus Nephritis Trial, a randomized trial of low‐dose versus high‐dose intravenous cyclophosphamide
Authors: Houssiau Frédéric A. , Vasconcelos Carlos , D'Cruz David , Sebastiani Gian Domenico , Garrido Enrique de Ramon , Danieli Maria Giovanna , Abramovicz Daniel , Blockmans Daniel , Mathieu Alessandro , Direskeneli Haner , Galeazzi Mauro , Gül Ahmet , Levy Yair , Petera Peter , Popovic Rajko , Petrovic Radmila , Sinico Renato Alberto , Cattaneo Roberto , Font Josep , Depresseux Geneviève , Cosyns Jean‐Pierre , Cervera Ricard
Published: October 2002

Objective

Glomerulonephritis is a severe manifestation of systemic lupus erythematosus (SLE) that is usually treated with an extended course of intravenous (IV) cyclophosphamide (CYC). Given the side effects of this regimen, we evaluated the efficacy and the toxicity of a course of low‐dose IV CYC prescribed as a remission‐inducing treatment, followed by azathioprine (AZA) as a remission‐maintaining treatment.

Methods

In this multicenter, prospective clinical trial (the Euro‐Lupus Nephritis Trial [ELNT]), we randomly assigned 90 SLE patients with proliferative glomerulonephritis to a high‐dose IV CYC regimen (6 monthly pulses and 2 quarterly pulses; doses increased according to the white blood cell count nadir) or a low‐dose IV CYC regimen (6 fortnightly pulses at a fixed dose of 500 mg), each of which was followed by AZA. Intent‐to‐treat analyses were performed.

Results

Followup continued for a median of 41.3 months in the low‐dose group and 41 months in the high‐dose group. Sixteen percent of those in the low‐dose group and 20% of those in the high‐dose group experienced treatment failure (not statistically significant by Kaplan‐Meier analysis). Levels of serum creatinine, albumin, C3, 24‐hour urinary protein, and the disease activity scores significantly improved in both groups during the first year of followup. Renal remission was achieved in 71% of the low‐dose group and 54% of the high‐dose group (not statistically significant). Renal flares were noted in 27% of the low‐dose group and 29% of the high‐dose group. Although episodes of severe infection were more than twice as frequent in the high‐dose group, the difference was not statistically significant.

Conclusion

The data from the ELNT indicate that in European SLE patients with proliferative lupus nephritis, a remission‐inducing regimen of low‐dose IV CYC (cumulative dose 3 gm) followed by AZA achieves clinical results comparable to those obtained with a high‐dose regimen.
Patient preferences for treatment of lupus nephritis
Authors: Fraenkel Liana , Bogardus Sidney , Concato John
Published: October 2002

Objective

To examine the amount of improvement in renal survival that lupus patients require before choosing cyclophosphamide over azathioprine for the treatment of lupus nephritis.

Methods

Patients were presented with descriptions of cyclophosphamide and azathioprine and asked to indicate their preferred choice if each conferred an equal probability of renal survival. Strength of preference was assessed by systematically increasing the probability of renal survival of the more toxic treatment until the respondent's choice switched.

Results

Ninety‐three well‐educated women (mean age ± SD 40 ± 7 years) participated in the study. Ninety‐eight percent (91/93) of the participants chose azathioprine over cyclophosphamide when both drugs conferred an equal probability of renal survival. Although most subjects switched preferences to cyclophosphamide for better renal survival, 31% (28/91) were unwilling to switch from azathioprine to cyclophosphamide for improved short‐term renal survival, and 15% (14/91) were unwilling to switch from azathioprine to cyclophosphamide for improved long‐term renal survival.

Conclusion

Although the majority of patients switched preferences to cyclophosphamide for better renal survival, a substantial minority was unwilling to accept the toxicity associated with cyclophosphamide, even if it was much better than azathioprine at preventing renal failure.
Information‐seeking and mediated searching. Part 1. Theoretical framework and research design
Authors: Spink Amanda , Wilson T.D. , Ford Nigel , Foster Allen , Ellis David
Published: October 2002

Our project has investigated the processes of mediated information retrieval (IR) searching during human information‐seeking processes to characterize aspects of this process, including information seekers' changing situational contexts; information problems; uncertainty reduction; successive searching, cognitive styles; and cognitive and affective states. The research has involved observational, longitudinal data collection in the United States and United Kingdom. Three questionnaires were used for pre‐ and postsearch interviews: reference interview, information seeker postsearch, and search intermediary postsearch questionnaires. In addition, the Sheffield team employed a fourth set of instruments in a follow‐up interview some 2 months after the search. A total of 198 information seekers participated in a mediated on‐line search with a professional intermediary using the Dialog Information Service. Each mediated search process was audio taped and search transaction log recorded. The findings are presented in four parts. Part I presents the background, theoretical framework, models, and research design used during the research. Part II is devoted to exploring changes in information seekers' uncertainty during the mediated process. Part III provides results related to successive searching. Part IV reports findings related to cognitive styles, individual differences, age and gender. Additional articles that discuss further findings from this complex research project, including: (1) an integrated model of information seeking and searching, (2) assessment of mediated searching, and (3) intermediary‐information seeker communication, are in preparation and will be published separately.
Information seeking and mediated searching study. Part 3. Successive searching
Authors: Spink Amanda , Wilson T.D. , Ford Nigel , Foster Allen , Ellis David
Published: October 2002

Our project has investigated the processes of mediated information retrieval (IR) searching during human information‐seeking processes to characterize aspects of this process, including information seekers' changing situational contexts; information problems; uncertainty reduction; successive searching, cognitive styles; and cognitive and affective states. The research has involved observational, longitudinal data collection in the United States and the United Kingdom. Three questionnaires were used for pre‐ and postsearch interviews: reference interview, information‐seeker postsearch, and search intermediary postsearch questionnaires. In addition, the Sheffield team employed a fourth set of instruments in a follow‐up interview some 2 months after the search. A total of 198 information seekers participated in a mediated on‐line search with a professional intermediary using the Dialog Information Service. Each mediated search process was audiotaped and search transaction logs recorded. The findings are presented in four parts. Part I presents the background, theoretical framework, models, and research design used during the research. Part II is devoted to exploring changes in information seekers' uncertainty during the mediated process. Part III provides results related to successive searching. Part IV reports findings related to cognitive styles, individual differences, age and gender. Additional articles that discuss further findings from this complex research project, including: (1) an integrated model of information seeking and searching, (2) assessment of mediated searching, and (3) intermediary information‐seeker communication, are in preparation and will be published separately.
An investigation of the influence of indexing exhaustivity and term distributions on a document space
Authors: Wolfram Dietmar , Zhang Jin
Published: October 2002

The authors investigate the influence of index term distributions, and indexing exhaustivity levels on the document space within a visual information retrieval environment called DARE. Using combinations of three levels of term distributions (shallow, observed, steep) and indexing exhaustivity (low, observed, high), hypothetical document sets were generated and projected onto the DARE environment. The results from the simulated document sets demonstrate the importance of term distribution and exhaustivity characteristics on the density of document spaces and their implications for retrieval, particularly when different term weighting schemes are used. The results also demonstrate how different combinations of exhaustivity and term distributions may result in similar document space density characteristics.
Evaluation of SupermixTM as an in vitro model of human liver microsomal drug metabolism
Authors: Venkatakrishnan Karthik , von Moltke Lisa L. , Greenblatt David J.
Published: October 2002

SUPERMIXTM is a commercially available formulation of insect cell‐expressed human drug‐metabolizing cytochrome P450 (CYP) isoforms, mixed in proportions that are optimized to parallel their relative activities in human liver microsomes. We have evaluated the apparent functional affinity and capacity of individual CYP isoforms in SUPERMIXTM in comparison with microsomes from a panel of 12 human livers, using enzyme kinetic studies of isoform‐selective index reactions. In addition, we have measured the concentration of NADPH cytochrome P450 oxidoreductase (OR) in SUPERMIXTM and compared it with the concentrations of this accessory electron transfer protein in human liver microsomes. No important differences were evident in the catalytic activities of CYPs 1A2, 2C8, 2C9, 2C19, 2D6 and 3A4 between SUPERMIXTM and human liver microsomes. However, SUPERMIXTM lacks CYP2B6 activity and did not hydroxylate the antidepressant bupropion, a clinically relevant substrate of this enzyme. In addition, the concentration of OR in SUPERMIXTM (1198 pmol mg protein−1) is 17‐fold higher than the mean value in human liver microsomes (70 pmol mg protein−1). In conclusion, SUPERMIXTM lacks CYP2B6 activity and contains supraphysiological concentrations of the accessory electron transfer protein OR. These factors should be considered when this formulation is used as an in vitro model in human liver microsomal drug metabolism studies. Copyright © 2002 John Wiley & Sons, Ltd.
The folic acid biosynthesis pathway in bacteria: evaluation of potential for antibacterial drug discovery
Authors: Bermingham Alun , Derrick Jeremy P.
Published: October 2002

The potential of the folic acid biosynthesis pathway as a target for the development of antibiotics has been acknowledged for many years and validated by the clinical use of several drugs. Recently, the crystal structures of all but one of the enzymes in the pathway from GTP to dihydrofolate have been determined. Given that structure‐based drug design strategies are now widely employed, these recent developments have prompted a re‐evaluation of the potential of each of the enzymes in the pathway as a target for development of specific inhibitors. Here, we review the current knowledge of the structure and mechanism of each enzyme in the bacterial folic acid biosynthesis pathway from GTP to dihydrofolate and draw conclusions regarding the potential of each enzyme as a target for therapeutic intervention. BioEssays 24:637–648, 2002. © 2002 Wiley Periodicals, Inc.
Going malignant: the hypoxia‐cancer connection in the prostate
Authors: Hochachka P.W. , Rupert J.L. , Goldenberg L. , Gleave M. , Kozlowski P.
Published: October 2002

The metabolic organization of both normal and malignant prostate cellular phenotypes involves some unusual and surprising features. In particular, both conditions exhibit ratios of NADH/NAD+ and NADPH/NADP+ charactersitic of high oxidative states despite a chronic shortage of O2 in both conditions. In this paper, we observe that, in prostate cancer cells, the oxidizing power of the fatty acid synthesis (FAS) pathway is so large that redox is stabilized more favorably (more oxidized) than in normal prostate cells. This FAS‐facilitated redox improvement occurs despite the fact that malignant cells are more O2 limited and therefore express more hypoxia inducible factor 1 (HIF1) and express hypoxia‐regulated genes more robustly. This unusual metabolic situation clearly separates direct regulatory effects of redox balance from secondary effects of hypoxia per se. The physiological significance of the FAS pathway is thus the harnessing of its oxidizing power for improving redox balance despite conditions of more extreme hypoxia. Similar hypoxia defense strategies are found in animal species that are unusually tolerant to oxygen lack. Our hypothesis is that the metabolic organization in the “low zinc, low citrate” phenotype reflects an hypoxia‐defense adaptation geared toward redox balance, with prostate cancer cells being relatively more oxidized, even if more hypoxic, than normal prostate cells. Recognition and understanding of these redox balancing and hypoxia defense functions may lead to new intervention strategies by developing new intracellular targets for prostate cancer therapy. BioEssays 24:749–757, 2002. © 2002 Wiley Periodicals, Inc.
Hydration of biological molecules: Lipids versus nucleic acids
Authors: Pohle W. , Gauger D. R. , Dornberger U. , Birch‐Hirschfeld E. , Selle C. , Rupprecht A. , Bohl M.
Published: October 2002

We used FTIR spectroscopy to comparatively study the hydration of films prepared from nucleic acids (DNA and double‐stranded RNA) and lipids (phosphatidylcholines and phosphatidylethanolamines chosen as the most abundant ones) at room temperature by varying the ambient relative humidity in terms of solvent‐induced structural changes. The nucleic acids and phospholipids both display examples of polymorphism on the one hand and structural conservatism on the other; even closely related representatives behave differently in this respect. DNA undergoes a hydration‐driven A–B conformational transition, but RNA maintains an A‐like structure independently of the water activity. Similarly, a main transition between the solid and liquid‐crystalline phases can be induced lyotropically in certain phosphatidylcholines, while their phosphatidylethanolamine counterparts do not exhibit chain melting under the same conditions. A principal difference concerning the structural changes that occur in the studied biomolecules is given by the relevant water–substrate stoichiometries. These are rather high in DNA and often low in phospholipids, suggesting different mechanisms of action of the hydration water that appears to induce structural changes on global‐ and local‐mode levels, respectively. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 499–503, 2002
Study of high molecular weight wheat glutenin subunit 1Dx5 by 13C and 1H solid‐state NMR spectroscopy. I. Role of covalent crosslinking
Authors: Alberti Enrica , Gilbert Simon M. , Tatham Arthur S. , Shewry Peter R. , Gil Ana M.
Published: October 2002

This work describes a carbon and proton solid‐state NMR study of the hydration of a high molecular weight wheat glutenin subunit, 1Dx5. The effect of the presence of disulfide bonds on the hydration behavior of the subunit is investigated by a comparison of the unalkylated and alkylated forms of the protein. Hydration induces partial plasticization of the protein so that some segments become more mobile than others. The 13C cross‐polarization and magic‐angle spinning (MAS) spectra of the samples in the dry state and at two hydration levels (∼40 and ∼65% D2O) were used to monitor the protein fraction resisting plasticization (trains). Conversely, 13C single pulse excitation and 1H‐MAS experiments were used to gain information on the more plasticized segments (loops). The molecular motion of the two protein dynamic populations was further characterized by 13C T1 and 1H T1ρ, T2, and T1 relaxation times. The results suggest that hydration leads to the formation of a network held by a cooperative action of hydrogen bonded glutamines and some hydrophobic interactions. The looser protein segments are suggested to be glycine‐ and glutamine‐rich segments. The primary structure is therefore expected to significantly determine the proportion of trains and loops in the network. The presence of disulfide bonds was observed to promote easier plasticization of the protein and the formation of a more mobile network, probably involving a higher number of loops and/or larger loops. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 487–498, 2002
Determination of α‐helix and β‐sheet stability in the solid state: A solid‐state NMR investigation of poly(L‐alanine)
Authors: Henzler Wildman Katherine A. , Lee Dong‐Kuk , Ramamoorthy A.
Published: October 2002

The relative stability of α‐helix and β‐sheet secondary structure in the solid state was investigated using poly(L‐alanine) (PLA) as a model system. Protein folding and stability has been well studied in solution, but little is known about solid‐state environments, such as the core of a folded protein, where peptide packing interactions are the dominant factor in determining structural stability. 13C cross‐polarization with magic angle spinning (CPMAS) NMR spectroscopy was used to determine the backbone conformation of solid powder samples of 15‐kDa and 21.4‐kDa PLA before and after various sample treatments. Reprecipitation from helix‐inducing solvents traps the α‐helical conformation of PLA, although the method of reprecipitation also affects the conformational distribution. Grinding converts the secondary structure of PLA to a final steady‐state mixture of 55% β‐sheet and 45% α‐helix at room temperature regardless of the initial secondary structure. Grinding PLA at liquid nitrogen temperatures leads to a similar steady‐state mixture with 60% β‐sheet and 40% α‐helix, indicating that mechanical shear force is sufficient to induce secondary structure interconversion. Cooling the sample in liquid nitrogen or subjecting it to high pressure has no effect on secondary structure. Heating the sample without grinding results in equilibration of secondary structure to 50% α‐helix/50% β‐sheet at 100°C when starting from a mostly α‐helical state. No change was observed upon heating a β‐sheet sample, perhaps due to kinetic effects and the different heating rate used in the experiments. These results are consistent with β‐sheet approximately 260 J/mol more stable than α‐helix in solid‐state PLA. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 246–254, 2002
Sequence‐specific recognition of DNA by hydrophobic, alanine‐rich mutants of the basic region/leucine zipper motif investigated by fluorescence anisotropy
Authors: Bird Gregory H. , Lajmi Ajay R. , Shin Jumi A.
Published: October 2002

We generated minimalist proteins capable of sequence‐specific, high‐affinity binding of DNA to probe how proteins are used and can be used to recognize DNA. In order to quantify binding affinities and specificities in our protein–DNA system, we used fluorescence anisotropy to measure in situ the thermodynamics of binding of alanine‐rich mutants of the GCN4 basic region/leucine zipper (bZIP) domain to DNA duplexes containing target sites AP‐1 (5′‐TGACTCA‐3′) or ATF/CREB (5′‐TGACGTCA‐3′). We simplified the α‐helical bZIP molecular recognition scaffold by alanine substitution: 4A, 11A, and 18A contain four, eleven, and eighteen alanine mutations in their DNA‐binding basic regions, respectively. DNase I footprinting analysis demonstrates that all bZIP mutants retain the sequence‐specific DNA‐binding function of native GCN4 bZIP. Titration of fluorescein‐labeled oligonucleotide duplexes with increasing amounts of protein yielded low nanomolar dissociation constants for all bZIP mutants in complex with the AP‐1 and ATF/CREB sites: binding to the nonspecific control duplex was > 1000‐fold weaker. Remarkably, the most heavily mutated protein 18A, containing 24 alanines in its 27‐residue basic region, still binds AP‐1 and ATF/CREB with dissociation constants of 15 and 7.8 nM, respectively. Similarly, wild‐type bZIP binds these sites with Kd values of 9.1 and 14 nM. 11A also displays low nanomolar dissociation constants for AP‐1 and ATF/CREB, while 4A binds these sites with ∼ 10‐fold weaker Kd values. Thus, both DNA‐binding specificity and affinity are maintained in all our bZIP derivatives. This Ala‐rich scaffold may be useful in design and synthesis of small α‐helical proteins with desired DNA‐recognition properties capable of serving as therapeutics targeting transcription. © 2002 Wiley Periodicals, Inc. Biopolymers 65: 10–20, 2002
Effect of electrical charges and fields on injury and viability of airborne bacteria
Authors: Mainelis Gediminas , Górny Rafał L. , Reponen Tiina , Trunov Mikhaylo , Grinshpun Sergey A. , Baron Paul , Yadav Jagjit , Willeke Klaus
Published: October 2002

In this study, the effects of the electric charges and fields on the viability of airborne microorganisms were investigated. The electric charges of different magnitude and polarity were imparted on airborne microbial cells by a means of induction charging. The airborne microorganisms carrying different electric charge levels were then extracted by an electric mobility analyzer and collected using a microbial sampler. It was found that the viability of Pseudomonas fluorescens bacteria, used as a model for sensitive bacteria, carrying a net charge from 4100 negative to 30 positive elementary charges ranged between 40% and 60%; the viability of the cells carrying >2700 positive charges was below 1.5%. In contrast, the viability of the stress‐resistant spores of Bacillus subtilis var. niger (used as simulant of anthrax‐causing Bacillus anthracis spores when testing bioaerosol sensors in various studies), was not affected by the amount of electric charges on the spores. Because bacterial cells depend on their membrane potential for basic metabolic activities, drastic changes occurring in the membrane potential during aerosolization and the local electric fields induced by the imposed charges appeared to affect the sensitive cells' viability. These findings facilitate applications of electric charging for environmental control purposes involving sterilization of bacterial cells by imposing high electric charges on them. The findings from this study can also be used in the development of new bioaerosol sampling methods based on electrostatic principles. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 229–241, 2002.
Advantages of using non‐isothermal bioreactors for the enzymatic synthesis of antibiotics: The penicillin G acylase as enzyme model
Authors: Travascio P. , Zito E. , De Maio A. , Schroën C. G. P. H. , Durante D. , De Luca P. , Bencivenga U. , Mita D. G.
Published: October 2002

A new hydrophobic and catalytic membrane was prepared by immobilizing Penicillin G acylase (PGA, EC.3.5.1.11) from E. coli on a nylon membrane, chemically grafted with butylmethacrylate (BMA). Hexamethylenediamine (HMDA) and glutaraldehyde (Glu) were used as a spacer and coupling agent, respectively. PGA was used for the enzymatic synthesis of cephalexin, using D(‐)‐phenylglycine methyl ester (PGME) and 7‐amino‐3‐deacetoxycephalosporanic acid (7‐ADCA) as substrates. Several factors affecting this reaction, such as pH, temperature, and concentrations of substrates were investigated. The results indicated good enzyme‐binding efficiency of the pre‐treated membrane, and an increased stability of the immobilized PGA towards pH and temperature. Calculation of the activation energies showed that cephalexin production by the immobilized biocatalyst was limited by diffusion, resulting in a decrease of enzyme activity and substrate affinity. Temperature gradients were employed as a way to reduce the effects of diffusion limitation. Cephalexin was found to linearly increase with the applied temperature gradient. A temperature difference of about 3°C across the catalytic membrane resulted into a cephalexin synthesis increase of 100% with a 50% reduction of the production times. The advantage of using non‐isothermal bioreactors in biotechnological processes, including pharmaceutical applications, is also discussed. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 334–346, 2002.
Rapid sampling for analysis of in vivo kinetics using the BioScope: A system for continuous‐pulse experiments
Authors: Visser Diana , van Zuylen Gertan A. , van Dam Jan C. , Oudshoorn Arthur , Eman Michael R. , Ras Cor , van Gulik Walter M. , Frank Johannes , van Dedem Gijs W. K. , Heijnen Joseph J.
Published: October 2002

In this article we present a novel device, the BioScope, which allows elucidation of in vivo kinetics of microbial metabolism via perturbation experiments. The perturbations are carried out according to the continuous‐flow method. The BioScope consists of oxygen permeable silicon tubing, connected to the fermentor, through which the broth flows at constant velocity. The tubing has a special geometry (serpentine channel) to ensure plug flow. After leaving the fermentor, the broth is mixed with a small flow of perturbing agent. This represents the start of the perturbation. The broth is sampled at different locations along the tubing, corresponding to different incubation times. The maximal incubation time is 69 s; the minimally possible time interval between the samples is 3–4 s. Compared to conventional approaches, in which the perturbation is carried out in the fermentor, the BioScope offers a number of advantages. (1) A large number of different perturbation experiments can be carried out on the same day, because the physiological state of the fermentor is not perturbed. (2) In vivo kinetics during fed‐batch experiments and in large‐scale reactors can be investigated. (3) All metabolites of interest can be measured using samples obtained in a single experiment, because the volume of the samples is unlimited. (4) The amount of perturbing agent spent is minimal, because only a small volume of broth is perturbed. (5) The system is completely automated. Several system properties, including plug‐flow characteristics, mixing, oxygen and carbon dioxide transfer rates, the quenching time, and the reproducibility have been explored, with satisfactory results. Responses of several glycolytic intermediates in Saccharomyces cerevisiae to a glucose pulse, measured using a conventional approach are compared to results obtained with the BioScope. The agreement between the results demonstrates that the BioScope is indeed a promising device for studying in vivo kinetics. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 674–681, 2002.