bluuebunny/crossref_metadata_2025 huggingface dataset:
Enterohemolysin operon of Shiga toxin‐producing Escherichia coli: a virulence function of inflammatory cytokine production from human monocytes
Authors: Taneike Ikue , Zhang Hui-Min , Wakisaka-Saito Noriko , Yamamoto Tatsuo
Published: October 2002

Shiga toxin‐producing Escherichia coli (STEC) is associated with hemolytic uremic syndrome (HUS). Although most clinical isolates of STEC produce hemolysin (called enterohemolysin), the precise role of enterohemolysin in the pathogenesis of STEC infections is unknown. Here we demonstrated that E. coli carrying the cloned enterohemolysin operon (hlyC, A, B, D genes) from an STEC human strain induced the production of interleukin‐1β (IL‐1β) through its mRNA expression but not tumor necrosis factor‐α from human monocytes. No IL‐1β release was observed with an enterohemolysin (HlyA)‐negative, isogenic E. coli strain carrying a mutation in the hlyA gene. The data suggest that enterohemolysin, a pore‐forming toxin, induces the production of IL‐1β, which is one of serum risk markers for HUS.
Disruption of the glucosylceramide biosynthetic pathway in Aspergillus nidulans and Aspergillus fumigatus by inhibitors of UDP‐Glc:ceramide glucosyltransferase strongly affects spore germination, cell cycle, and hyphal growth
Authors: Levery Steven B , Momany Michelle , Lindsey Rebecca , Toledo Marcos S , Shayman James A , Fuller Matthew , Brooks Kelly , Doong Ron Lou , Straus Anita H , Takahashi Helio K
Published: October 2002

The opportunistic mycopathogen Aspergillus fumigatus expresses both glucosylceramide and galactosylceramide (GlcCer and GalCer), but their functional significance in Aspergillus species is unknown. We here identified and characterized a GlcCer from Aspergillus nidulans, a non‐pathogenic model fungus. Involvement of GlcCer in fungal development was tested on both species using a family of compounds known to inhibit GlcCer synthase in mammals. Two analogs, D‐threo‐1‐phenyl‐2‐palmitoyl‐3‐pyrrolidinopropanol (P4) and D‐threo‐3′,4′‐ethylenedioxy‐P4, strongly inhibited germination and hyphal growth. Neutral lipids from A. fumigatus cultured in the presence of these inhibitors displayed a significantly reduced GlcCer/GalCer ratio. These results suggest that synthesis of GlcCer is essential for normal development of A. fumigatus and A. nidulans.
Quality management practices and their relationship to buyer’s supplier ratings: a study in the Korean automotive industry
Authors: Park Seungwook , Hartley Janet L , Wilson Darryl
Published: October 2002

This research explores if quality management practices are different among suppliers whose performance is rated high, medium, or low by a common buying company and identifies which specific practices contribute to the differences. The entire population of first‐tier suppliers to a Korean auto assembler was surveyed to measure use of quality management practices. Useable returns were received from 25% of the suppliers surveyed. To measure conformance quality and overall rating, suppliers were categorized into high, medium, and low performing groups based on the buying company’s data. Multivariate analysis of variance was done using general linear model (GLM‐MANOVA) to explore differences in the high‐, medium‐, and low‐performing supplier groups based on their use of quality management practices. No statistically significant differences were found when suppliers were categorized based on conformance quality. However, when categorized based on overall rating, the highest rated suppliers were found to emphasize process management and employee satisfaction to a greater degree than the lowest rated suppliers.
Relationships between implementation of TQM, JIT, and TPM and manufacturing performance
Authors: Cua Kristy O. , McKone Kathleen E. , Schroeder Roger G.
Published: October 2002

Research on Total Quality Management (TQM), Just‐in‐Time (JIT) and Total Productive Maintenance (TPM) generally investigates the implementation and impact of these manufacturing programs in isolation. However, many researchers believe and argue conceptually the value of understanding the joint implementation and effect of manufacturing programs. This study investigates the practices of the three programs simultaneously. We find that there is evidence supporting the compatibility of the practices in these programs and that manufacturing performance is associated with the level of implementation of both socially‐ and technically‐oriented practices of the three programs.
Effective case research in operations management: a process perspective
Authors: Stuart I , McCutcheon D , Handfield R , McLachlin R , Samson D
Published: October 2002

Despite many calls for case‐based operations management research, the successful publication rate of such articles in top‐tier journals has been less than stellar. A five step case‐based research and dissemination process is presented. Guidance is given to future researchers for each step in the process. In addition, areas of weakness are examined and discussed in detail. Future potential research questions in operations management considered to be appropriate for the case‐based method are highlighted.
Neutrophils and macrophages accumulate sequentially following Achilles tendon injury
Authors: Marsolais David , Cǒté Claude H. , Frenette Jérǒme
Published: October 2002

Structural damage and inflammation occur following tendon injury. The purpose of this study was to determine the time course of inflammatory cell accumulation in two animal models of acute tendinopathy. In the first model, rat Achilles tendons were exposed by blunt dissection, injected with collagenase and sacrificed at 1, 3, 7, 14 and 28 days. In the second model, collagenase was injected percutaneously and rats were sacrificed after 1 and 3 days. Sham animals were sacrificed at 1 and 3 days in both models. Neutrophil and ED1+ macrophage populations increased by 46‐ and 18‐fold, respectively, after 1 day in surgically exposed Achilles tendons (EAT) injected with collagenase. Neutrophils dropped by 70% while the concentration of ED1+ macrophages remained constant at day 3 post‐injury. Neutrophils and ED1+ macrophages returned to control values after 7 and 14 days, respectively. ED2+ macrophages showed a tendency to increase at day 28 although no significant difference was observed relative to ambulatory controls. Collagenase injected percutaneously reduced the extent of inflammation compared with operated animals. Thus, injured tendons exhibited a specific sequence of inflammatory cell accumulation which varied in intensity according to the modality used for collagenase injection. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Mixed‐mode failure response of the cement–bone interface
Authors: Mann Kenneth A. , Mocarski Robbin , Damron Leatha A. , Allen Matthew J. , Ayers David C.
Published: October 2002

Mechanical failure of the cement—bone interface can contribute to clinical loosening of cemented total hip replacements. The conditions that cause loosening are poorly understood, in part, due to a lack of information on the mechanical behavior of the cement—bone interface. The purpose of this study was to determine the mechanical behavior of the cement—bone interface due to mixed‐mode (combined tension and shear) loading and to develop a failure model for the cement—bone interface. Laboratory tests of machined cement—bone test specimens were performed with mixed‐mode loading conditions (loading angles of 22.5°, 45°, and 67.5°) to determine the mechanical response in the pre‐yield and post‐yield state. After accounting for the quantity of interdigitated bone as a covariate, the mixed‐mode data were combined with previous tension (0°) and shear data (90°) to develop a failure model for the cement—bone interface. The strength of the interface was positively correlated with the quantity of interdigitated bone (r2 = 0.70, 0.53, 0.49, for 22.5°, 45°, and 67.5°, respectively). There was a significant increase in failure strength (P < 0.001) with increasing mixed‐mode angle. When all data were incorporated into an elliptical failure criterion, the average error between the actual and predicted strength was 33%. These results can now be incorporated into constitutive models of the cement—bone interface to determine the initiation and progression of interface failure in cemented total hip replacements. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Compressive properties and function—composition relationships of developing bovine articular cartilage
Authors: Williamson Amanda K. , Chen Albert C. , Sah Robert L.
Published: October 2002

The composition of cartilage is known to change during fetal and postnatal development. The objectives of this study were to characterize the compressive biomechanical properties of the 1 mm thick articular layer of cartilage of the distal femur from third‐trimester bovine fetuses, from 1 to 3 week old bovine calf and from young adult bovine knees, and to correlate these properties with tissue components. The confined compression modulus increased 180% from the fetus to the calf and adult. The hydraulic permeability at 45% offset compression (relative to the free‐swelling thickness) decreased by 70% from fetus to adult. These development‐associated changes in biomechanical properties were primarily associated with a marked (∼2–3‐fold) increase during development in collagen content and no detectable change in glycosaminoglycan (GAG) content. A role for collagen in the compressive properties of cartilage and the gradual increase in collagen during development suggest that collagen metabolism is critical for cartilage tissue engineering and repair therapies. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Synovial fluid biomarker levels predict articular cartilage damage following complete medial meniscectomy in the canine knee
Authors: Carlson Cathy S. , Guilak Farshid , Vail Thomas P. , Gardin Jean F. , Kraus Virginia B.
Published: October 2002

The purposes of this study were to document the histological changes present in the tibial plateaus 12 weeks after complete medial meniscectomy in dogs and to determine if synovial lavage fluid biomarker levels are predictive of the severity of joint damage. Twelve adult dogs underwent complete unilateral medial meniscectomy and synovial lavage fluid biomarker levels, including cartilage oligomeric matrix protein (COMP), keratan sulfate (5D4), 3B3(−), and 3B3(+), were measured serially at 4‐week intervals. The dogs were euthanized 12 weeks after surgery and each medial and lateral tibial plateau from the meniscectomized and contralateral knees was graded histologically. Histological data were analyzed using principal components analysis, which resulted in 4 factors that explained 70% of the variation in the data. Factor 2 (weighted most heavily by subchondral bone thickness) and Factor 3 (representative of articular cartilage damage) were significantly affected by compartmental site (P < 0.01 for both). Both of these factors were highest in the medial tibial plateau of the meniscectomized knee, and Factor 3 was significantly higher in this site than in the medial tibial plateau of the contralateral knee (P < 0.01). Peak levels of all 4 synovial lavage fluid biomarkers occurred at 4 weeks post‐meniscectomy and 4‐week minus baseline levels of all biomarkers were significantly correlated with the Factor 3 scores. This study demonstrates that significant articular cartilage damage occurs relatively quickly following complete medial meniscectomy in dogs and establishes the content and criterion validity for these synovial fluid lavage biomarkers in canine meniscectomy as surrogate measures of articular cartilage damage. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Tissue response during monofocal and bifocal leg lengthening in patients
Authors: Aarnes Gudrun Trøite , Steen Harald , Kristiansen Leif Pål , Ludvigsen Per , Reikerås Olav
Published: October 2002

The purpose of this investigation was to compare the tissue response during mono‐ and bifocal limb lengthening. The study includes four patients undergoing leg lengthening. All patients started out bifocally with a total diurnal distraction of 1.75 mm, but proceeded monofocally with a rate of 1 mm a day when the distal distraction was terminated due to contractures or pain. The tissue response was monitored by registration of axial force in the distraction rods. The force increased linearly during bifocal lengthening, but culminated or decreased in the period of monofocal lengthening. Average tissue stiffness, defined as the immediate force increase due to each 0.25 mm distraction increment, was significantly higher in the bifocal lengthening phase. The force decay between each distraction was significantly lower during bifocal lengthening, thus indicating decreased tissue accommodation. Details in the force registrations indicated that the soft tissue, not the regenerate, was the main contributor to the tensile force. Conclusively, the tissues at the two osteotomy sites do not lengthen independently. Bifocal lengthening exposes the entire soft tissue to large loads, resulting in increased tissue stiffness and reduced ability to adapt to the increased length. Accordingly, bifocal leg lengthening requires special attention to soft tissue adaptation. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
An in vivo study of peripheral nerves in continuity: biomechanical and physiological responses to elongation
Authors: Driscoll Peter J. , Glasby Michael A. , Lawson Graham M.
Published: October 2002

Using an animal model, the in vivo visco‐elastic properties of peripheral nerve in continuity were examined. The nerves were stretched by either 1 cm – Group A (8.8% strain) or 2 cm – Group B (16.1% strain). At constant strain, the stress‐relaxation curves were plotted. Maximal relaxation was observed in the first 20 min. After 1 h, the decrease in tensions in Groups A and B were 36.8% and 41.8%, respectively. Throughout this hour and for 30 min after the release of tension, regular recordings of nerve blood flow using laser doppler flowmetry and peak nerve conduction velocity were taken. Nerve blood flow was reduced by similar amounts (Group A, 70%; Group B, 78%) by application of traction. On release, however, Group A displayed a reactive hyperaemia (blood flow 151% starting value) while Group B failed to recover (50% starting value at 30 min). Peak nerve conduction velocity was not significantly altered in Group A in response to traction, whereas in Group B the result was a gradual, but significant reduction in peak velocity to 66% starting value. The lack of correlation between blood flow and peak nerve conduction velocity in these studies suggests that ischaemia is not solely responsible for the increased latency. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The X‐ray attenuation characteristics and density of human calcaneal marrow do not change significantly during adulthood
Authors: Les C. M. , Whalen R. T. , Beaupré G. S. , Yan C. H. , Cleek T. M. , Wills J. S.
Published: October 2002

Changes in the material characteristics of bone marrow with aging can be a significant source of error in measurements of bone density when using X‐ray and ultrasound imaging modalities. In the context of computed tomography, dual‐energy computed techniques have been used to correct for changes in marrow composition. However, dual‐energy quantitative computed tomography (DE‐QCT) protocols, while increasing the accuracy of the measurement, reduce the precision and increase the radiation dose to the patient in comparison to single‐energy quantitative computed tomography (SE‐QCT) protocols. If the attenuation properties of the marrow for a particular bone can be shown to be relatively constant with age, it should be possible to use single‐energy techniques without experiencing errors caused by unknown marrow composition.

Marrow was extracted by centrifugation from 10 mm thick frontal sections of 34 adult cadaver calcanei (28 males, 6 females, ages 17–65 years). The density and energy‐dependent linear X‐ray attenuation coefficient of each marrow sample were determined. For purposes of comparing our results, we then computed an effective CT number at two GE CT/i scan voltages (80 and 120 kVp) for each specimen. The coefficients of variation for the density, CT number at 80 kVp and CT number at 120 kVp were each less than 1%, and the parameters did not change significantly with age (p > 0.2, r2 < 0.02, power > 0.8 where the minimum acceptable r2 = 0.216). We could demonstrate no significant gender‐associated differences in these relationships. These data suggest that calcaneal bone marrow X‐ray attenuation properties and marrow density are essentially constant from the third through sixth decades of life. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
High frequency distraction improves tissue adaptation during leg lengthening in humans
Authors: Aarnes Gudrun Trøite , Steen Harald , Ludvigsen Per , Kristiansen Leif PÅL , Reikerås Olav
Published: October 2002

The present study investigates the effect of distraction frequency on the development of tensile force in the tissues during lengthening. Two patients with bilateral Ilizarov leg lengthening underwent distraction with high frequency in one leg and low frequency in the other. The clinical situation represented a unique model for investigating the effect of distraction frequency, as each individual served as its own control. Both patients had double level lengthening. Distraction frequency at the proximal lengthening zone was 0.25 mm × 4 in the first leg and 1/1440 mm once every minute in the other. Total diurnal distraction at the proximal metaphysis was 1 mm in both legs. In addition, a distal metaphyseal distraction of 0.25 mm × 3 daily was performed on each leg. The tissue's mechanical response was monitored by measuring the tensile force at the proximal osteotomy. Both patients experienced a significant lower level of force during the high frequency lengthening. The lower level of force was concluded to be due to improved soft tissue adaptation, rather than reduced bone regeneration. Accordingly, high distraction frequency was considered favourable to low frequency, and is recommended in large lengthenings where high force levels are expected. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Fatigue crack growth rate does not depend on mantle thickness: an idealized cemented stem construct under torsional loading
Authors: Hertzler Justin , Miller Mark A. , Mann Kenneth A.
Published: October 2002

Retrieval studies indicate that cemented stem loosening in femoral components of total hip replacement can initiate at the stem‐cement interface. The etiology of the crack propagation process from the stem‐cement interface is not well understood, but cracks are typically associated with thin cement mantles. In this study, a combination of experimental and computational methods was used to investigate the fatigue crack propagation process from the stem‐PMMA cement interface using a novel torsional loading model. Constructs with thin (1 mm), medium (3 mm) or thick (7 mm) cement mantles were evaluated. Crack growth was stable for all cases and the rate of crack growth diminished with increasing crack length. Crack growth rate did not depend on mantle thickness (p > 0.05) over the first 1 mm of crack length, but cracks in thin mantles reached the full thickness of the mantle in the fewest number of loading cycles. The fracture mechanics‐based finite element models indicated decreased stress intensity factors with increasing crack length and were consistent with the experimental findings. When combined with a fatigue crack growth Paris‐law for PMMA cement, the finite element models provided reasonable predictions of the crack growth process. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Effect of a heart failure clinic on survival and hospital readmission in patients discharged from acute hospital care
Authors: Azevedo Ana , Pimenta Joana , Dias Paula , Bettencourt Paulo , Ferreira António , Cerqueira‐Gomes Mário
Published: October 2002

Ambulatory care by physicians especially devoted to the management of heart failure (HF) has been reported to have beneficial effects. The aim of this work was to assess the effect of outpatient management at a HF clinic, as compared with care by the usual assistant physician, on prognosis of HF patients. In this non‐randomised study, we prospectively followed 339 patients after a hospitalisation index for HF, in order to compare prognosis between two groups of HF patients according to the ambulatory assistance setting: either a specific outpatient clinic (n‐157) or the usual assistant physician (n‐182). The outcomes assessed were all‐cause death or cardiac‐cause rehospitalisation during the first month after discharge and survival over the longer term. The risk of dying or being readmitted during the first month after discharge was significantly lower in patients followed at the HF clinic (adjusted odds ratio 0.23; 95% CI 0.12–0.46). Patients followed in the HF clinic also had an independent significantly lower hazard of dying during a longer‐term follow up of average length 373 days (adjusted hazard ratio 0.52; 95% CI 0.34–0.81). The results support the fact that a multidisciplinary and permanently available medical staff might be of relevance in improving outcomes in HF patients.
Whole blood impedance aggregometry for the assessment of platelet function in patients with congestive heart failure (EPCOT Trial)
Authors: Serebruany V.L. , McKenzie M.E. , Meister A.F. , Fuzaylov S.Y. , Gurbel P.A. , Atar D. , Gattis W.A. , O'Connor C.M.
Published: October 2002

Objective

Data from small studies have shown the presence of platelet abnormalities in patients with congestive heart failure (CHF). We sought to characterize the diagnostic utility of the whole blood aggregometry (WBA) in a random outpatient CHF population.

Methods

Blood samples were obtained for measurement of whole blood aggregation, shear‐induced closure time, platelet contractile force, expression of GP IIb/IIIa, and P‐selectin in 100 consecutive patients with CHF.

Results

Substantial inter‐individual variability of platelet characteristics exists in patients with CHF. There were no statistically significant differences when patients were divided by the incidence of vascular events, emergency revascularization needs, survival, or etiology of heart failure. Surprisingly, aspirin use did not affect instrument readings as well. Whole blood aggregometry correlates well with the closure time (r2‐0.587), and with GP IIb/IIIa expression (r2‐0.435). Significant but less strong correlation has been observed for the WBA with platelet P‐selectin expression (r2‐0.295), and no correlation was present for the platelet contractile force measures (r2‐0.030).

Conclusions

Despite the fact that patients with heart failure enrolled in the EPCOT trial exhibited marginal, sometimes oppositely directed changes, in their platelet characteristics, whole blood impedance aggregometry is indeed capable to serve as a valuable diagnostic tool, and may be successfully used as an established screening device in this population. Ability of the whole blood aggregometry to predict clinical outcomes, or for the monitoring of anti‐platelet agents in CHF patients, will be evaluated in the ongoing clinical trials.
Clinical depression is common and significantly associated with reduced survival in patients with non‐ischaemic heart failure
Authors: Faris R. , Purcell H. , Henein M.Y. , Coats A.J.S.
Published: October 2002

Several studies have shown that depression is an important predictor of morbidity and mortality in patients with ischaemic heart failure. We have investigated whether clinically recognised depression is linked to mortality in patients with non‐ischaemic heart failure due to dilated cardiomyopathy (DCM) in the Royal Brompton Hospital (RBH), a tertiary cardiac centre located in London, UK. We retrospectively examined a cohort of 396 consecutive adult patients with DCM who satisfied our inclusion and exclusion criteria identified from an echocardiographic database and the hospital medical records. Mean age was 53±15 years. In all, 83 patients (21%) were clinically depressed, the majority of which (60%) were taking antidepressant therapy. After a follow‐up period of 48 months, 83 (21%) patients died, 15 (4%) underwent cardiac transplantation and 130 (33%) were readmitted; 29 (35%) of the deaths and 40 (31%) of the readmissions were among clinically depressed patients. After 5 years, clinically depressed patients had significantly higher mortality and readmission rates than non‐depressed; 36 vs. 16% (hazards ratio for death, 3.0; 95% CI, 1.4–6.4;P‐0.004), and 87 vs. 74% (hazards ratio for readmission, 0.25; 95% CI, 0.07–0.90;P‐0.03), respectively. The risk of depression was greatly increased in the presence of other recognised adverse clinical variables at baseline. Depression increases the risk of death and readmission in patients with heart failure secondary to non‐ischaemic DCM. The risk associated with depression appears to be greatest among patients with milder disease, those with a shorter duration of symptoms and those demonstrating a lower systolic or diastolic blood pressure, renal impairment, or a restrictive left ventricular physiology on echocardiography. Interventions targeted at reducing depression warrant further study as a possible way to improve quality of life and/or outcome in patients with heart failure.
Flag Errors in Soccer Games: The Flash-Lag Effect Brought to Real Life
Authors: Baldo Marcus Vinicius C , Ranvaud Ronald D , Morya Edgard
Published: October 2002

In soccer games, an attacking player is said to be in an offside position if he or she is closer to the opponents' goal line than both the ball and the second-to-last defender. It is an offence for the attacker to be in an offside position and in active play at the moment a fellow team member plays the ball. Assistant referees often make mistakes when judging an offside offence, probably because of optical errors arising from the viewing angle adopted by them (Oudejans, Verheijen, Bakker, Gerrits, Steinbrückner, Beek, 2000 Nature404 33). Looking more closely at Oudejans et al's data, we show evidence that the flash-lag effect may contribute significantly to these mistakes. Participation of the flash-lag effect in assistant referees' misjudgments would take this perceptual phenomenon from laboratory setups to a real-life situation for the first time.
Calcium-regulated exocytosis of dense-core vesicles requires the activation of ADP-ribosylation factor (ARF)6 by ARF nucleotide binding site opener at the plasma membrane
Authors: Vitale Nicolas , Chasserot-Golaz Sylvette , Bailly Yannick , Morinaga Naoko , Frohman Michael A. , Bader Marie-France
Published: October 2002

The ADP ribosylation factor (ARF) GTP binding proteins are believed to mediate cytoskeletal remodeling and vesicular trafficking along the secretory pathway. Here we show that ARF6 is specifically associated with dense-core secretory granules in neuroendocrine PC12 cells. Stimulation with a secretagogue triggers the recruitment of secretory granules to the cell periphery and the concomitant activation of ARF6 by the plasma membrane-associated guanine nucleotide exchange factor, ARF nucleotide binding site opener (ARNO). Expression of the constitutively inactive ARF6(T27N) mutant inhibits secretagogue-dependent exocytosis from PC12 cells. Using a mutant of ARF6 specifically impaired for PLD1 stimulation, we find that ARF6 is functionally linked to phospholipase D (PLD)1 in the exocytotic machinery. Finally, we show that ARNO, ARF6, and PLD1 colocalize at sites of exocytosis, and we demonstrate direct interaction between ARF6 and PLD1 in stimulated cells. Together, these results provide the first direct evidence that ARF6 plays a role in calcium-regulated exocytosis in neuroendocrine cells, and suggest that ARF6-stimulated PLD1 activation at the plasma membrane and consequent changes in membrane phospholipid composition are critical for formation of the exocytotic fusion pore.
Influence of cargo size on Ran and energy requirements for nuclear protein import
Authors: Lyman Susan K. , Guan Tinglu , Bednenko Janna , Wodrich Harald , Gerace Larry
Published: October 2002

Previous work has shown that the transport of some small protein cargoes through the nuclear pore complex (NPC) can occur in vitro in the absence of nucleoside triphosphate hydrolysis. We now demonstrate that in the importin α/β and transportin import pathways, efficient in vitro transport of large proteins, in contrast to smaller proteins, requires hydrolyzable GTP and the small GTPase Ran. Morphological and biochemical analysis indicates that the presence of Ran and GTP allows large cargo to efficiently cross central regions of the NPC. We further demonstrate that this function of RanGTP at least partly involves its direct binding to importin β and transportin. We suggest that RanGTP functions in these pathways to promote the transport of large cargo by enhancing the ability of import complexes to traverse diffusionally restricted areas of the NPC.
A continuous improvement process at Severn Trent Water
Authors: Tennant Charles , Warwood Stephen J. , Mun Ping Chiang Minda
Published: October 2002

The paper presents the development of a continuous improvement process for the customer relations department at Severn Trent Water in the UK. In‐company research was carried out to identify the main barriers to continuous improvement in the areas of leadership, training, communication, motivation, teamwork, and change management. The study concluded that the company should develop an organisational culture and management style to support continuous improvement of daily working processes, and that change should be managed against the achievement of appropriate quality targets. A continuous improvement process was developed based on a structured problem‐solving model incorporating the application of established quality tools, to be applied by problem solving teams from the customer relations department. It was recommended that the team members should be trained in the problem solving process, and the related quality tools and techniques. Also, management should lead and support this approach by concentrating on team (rather than individual) performance achievement.
Between-days reliability of electromyographic measures of paraspinal muscle fatigue at 40, 50 and 60% levels of maximal voluntary contractile force
Authors: Arnall Frances A , Koumantakis George A , Oldham Jacqueline A , Cooper Robert G
Published: October 2002

Objective: To ascertain which percentage of maximal voluntary contractile force of the paraspinal muscles, when tested in a functional position, is most reliable for assessing electromyographic (EMG) fatigue changes.

Subjects: Ten healthy volunteers with no history of low back pain (six males).

Main outcome measures: The surface EMG signal during 60-second isometric contractions of the paraspinal muscles at 40, 50 and 60% levels of maximal voluntary contractile force was captured and analysed. Each contraction level was assessed on two occasions, at least three days apart. The initial median frequency, the decline in median frequency slope and the increase in root mean square values were assessed for between-days reliability, using intraclass correlation coefficients (ICCs) and standard errors of measurements (SEM). Normalized median frequency and root mean square values were also assessed.

Results: At 40% of maximal voluntary contraction, little or no EMG fatigue changes occurred in any of the observed parameters. At 50% maximal voluntary contraction the initial mean frequency and root mean square changes proved highly reliable, with ICCs ranging from 0.74 to 0.86 and 0.75 to 1.00 respectively. Normalizing the root mean square data reduced the reliability, but this was still acceptable with ICCs 0.70–0.83. The median frequency decline slope proved less reliable with ICCs 0.24–0.74 for raw and 0.26–0.77 for normalized data. At 60% maximal voluntary contraction the initial mean frequency proved as reliable as initial median frequency at 50% with ICCs 0.70–0.89. The raw and normalized root mean squares (ICCs 0.43–0.89 and 0.30–0.87 respectively) and raw and normalized median frequency (ICCs 0.27–0.51 and 0.24–0.53 respectively) changes were less reliable than at 50% MVC. Overall, the reliability is better at the L4/5 than at the L2/3 level.

Conclusion: Outcome measures taken at 50% maximal voluntary contraction are the most reliable in functional testing the paraspinal muscles of healthy volunteers. With initial median frequency and root mean square values being more reliable parameters than median frequency decline. At the L4/5 level, however, all parameters were acceptably reliable at 50% of maximum effort. However the between-subject variability of the median frequency decline and root mean square incline slopes suggest that these parameters are not yet fully suitable for monitoring fatigue changes during prolonged isometric contraction.
Water structure theory and some implications for drug design
Authors: Plumridge T H , Waigh R D
Published: October 2002

The development of theories of water structure has been hindered in the past by the difficulty of experimental measurement. Both measurement and computer modelling studies have now reached the stage where theoretical treatments of water structure are converging to a broadly acceptable model. In current understanding, water is a mixture of randomly hydrogen-bonded molecules and larger structures comprised of tetrahedral oxygen centres which, when hydrogen-bonded to each other, lead to five-membered and other rings which can aggregate to form three-dimensional structures. Evidence is taken from studies of the ices, from clathrates and other solid solutions, as well as from liquid solutions, that certain motifs occur very frequently and have relatively high stability, such as the (H2O)20 cavity-forming structure known from studies on clathrates. The implications of recent models of water structure for an understanding of biological events, including the interactions of drugs with receptors, are profound. It is becoming clear that modelling of aqueous solutions of any molecule must consider the explicit interactions with water molecules, which should not be regarded as a continuum: water itself is not a continuum. Solute molecules which possess hydrogen-bonding groups will provoke the formation of further hydrogen-bonding chains of water molecules: if these can form rings, such rings will tend to persist longer than chains, giving the solute a secondary identity of associated water which may play a role in molecular recognition. Solutes that do not have hydrogen-bonding capability, or regions of solutes which are non-polar, may also produce partial cage-like water structures that are characteristic of the solute.

The classification of many solutes as structure makers or structure breakers has relevance to the interactions between ligands and large biomolecules such as proteins. While it is generally accepted that sulfate and urea, respectively structure maker and breaker, may alter protein conformation through effects on water, it has not been recognised that bioactive ligands, which also change the conformation of proteins, may do so by a related, but more selective, mechanism. Very early studies of cell contents suggested that the associated water might be different from bulk water, a concept that lost support in the mid-20th century. Current theories of water structure may invite a reappraisal of this position, given the observation that structuring may extend for many molecular diameters from an ordered surface.
A novel insulin formulation can keep providing steady levels of insulin for much longer periods in-vivo
Authors: Takenaga Mitsuko , Yamaguchi Yoko , Kitagawa Aki , Ogawa Yasuaki , Mizushima Yutaka , Igarashi Rie
Published: October 2002

We have recently succeeded in preparing insulin-loaded microcapsules that release the insulin in a strictly controlled manner with little initial rapid release in-vitro or in-vivo. We show here the superiority of the best formulation prepared with co-poly(d,l-lactic/glycolic) acids (PLGA) (mean MW 5800, L/G ratio 50:50) with a main diameter of 15 ˜ 30 μm in-vivo. When 3.2% insulin-loaded PLGA microcapsules were subcutaneously given as a single dose to streptozotocin-induced hyperglycaemic rats (250 U kg−1), plasma insulin levels gradually increased and constant levels (30.3–94.1 μL−1) were sustained. Rats receiving the formulation once a week showed not only steady plasma insulin levels, but also gained weight at a similar speed to normal rats. Meanwhile, daily treatment with Humulin U (25 U kg−1) caused a transient high insulin level (2723.9 μU mL−1 at 1 h) in plasma, but the body weight of the rats was little changed. A pharmacological study in female Cynomolgus monkeys also revealed that the microcapsular formulation provided a flat release of insulin for longer periods and showed no immunogenic activity. In the near future, therefore, this insulin formulation could become very beneficial as a provider of basal insulin levels for insulin-dependent diabetic patients.
Polymer-coated microparticles for the sustained release of nitrofurantoin
Authors: Liu Jita , Chan Sui Y , Ho Paul C
Published: October 2002

Suspensions of nitrofurantoin (NTF) microparticles for controlled release were investigated in this study. The microparticles were enteric coated with various combinations of the two polymers, cellulose acetate phthalate/cellulose acetate butyrate (CAP/CAB) by a modified solvent evaporation method. Ratios of NTF to the two polymers (NTF/CAP/CAB) ranged from 1.0:1.6:0.4, 1.0:1.0:1.0, 1.0: 0.4:1.6 to 1.0:0.0:2.0. The encapsulation efficiency, percentage yield, determined by comparing the final mass of the microparticles with the initial mass of the ingredients used, distribution of particle size and the in-vitro dissolution profiles of the microparticles were determined. Based on light photographs for the evaluation of the microparticle morphology, the drug crystals appeared to be encapsulated sufficiently by the enteric polymers. In our study, the microparticles enteric coated with CAP/CAB in the ratio of 0.4:1.6 displayed the most satisfactory in-vitro release profile (reduced release in the simulated gastric fluid and sustained release in the simulated intestinal fluid). Thus, microparticles with NTF/CAP/CAB in the ratio of 1.0:0.4:1.6 were formulated into a suspension for further bioavailability and ulcerogenicity studies in Sprague–Dawley rats, with the suspension of NTF crystals as a control. The bioavailability study was carried out in eight rats fed with either the free NTF or the corresponding microparticles in a cross-over design. The ulcerogenicity study was carried out in three groups of six rats each: one group received no drug treatment; the control group was treated with free NTF; and the third group was treated with enteric-coated NTF microparticles. The bioavailability of NTF from the microparticles was comparable with the control. More importantly, there was notably less ulceration of the gastric mucosa observed after dosing with the microparticle suspension compared with that after the administration of the control suspension.
Determinant of the distribution volume at steady state for novel quinolone pazufloxacin in rats
Authors: Hayakawa Hiroyoshi , Takagi Kyoko , Takano Yoko Fukushima , Kawamura Yasuhito , Tsuji Akira
Published: October 2002

The distribution properties of the novel quinolone pazufloxacin (PZFX) in rats were compared with those of sparfloxacin (SPFX) and ofloxacin (OFLX). Following intravenous administration of these quinolones to rats, the distribution volume at steady state (Vdss) of PZFX was found to be 0.945 L kg−1, whereas for OFLX and SPFX it was 1.83 and 3.42 L kg1, respectively. In order to understand this difference in Vdss, first the contribution of each tissue to the Vdss using pharmacokinetic parameters was estimated and it was found that the type of tissue contributing the most was muscle. Subsequently, we determined the extent of tissue binding and uptake clearance (CLuptake) in the muscle. The ratio of unbound fraction of plasma to unbound fraction of muscle was almost equal for all quinolones tested, with values of 1.60, 1.52 and 1.32 for PZFX, OFLX and SPFX, respectively. In contrast, the tissue CLuptake of PZFX in the muscle (0.012 mL min−1 g−1) was significantly lower than that of OFLX and SPFX (0.118 and 0.195 mL min−1 g−1, respectively). These results suggest that the low Vdss value for PZFX can be attributed to the low CLuptake in the muscle.
Prediction of the volume of distribution of a drug: which tissue-plasma partition coefficients are needed?
Authors: Björkman Sven
Published: October 2002

The aim of this study was to identify the tissue-plasma partition coefficients (Kp) needed for an initial prediction of the volume of distribution at steady state (Vdss) of a drug in humans. Values of Kp were collected from the literature. Only Kp values plausibly representing true steady state distribution were accepted, and data had to be available for muscle, fat, skin and at least five other organs. The apparent volume of distribution of a drug in an organ/tissue (Vapp) was calculated as Kp multiplied by the volume of the organ/tissue, and the Vdss as the sum of all available Vapp values. The percentage contribution of each Vapp to the Vdss was estimated. In addition, linear regressions were calculated between Kp values of all drugs in a specific organ/tissue and Kp in muscle or fat. Finally, the Vdss was re-calculated using (for basic drugs) the Kp in fat to calculate Vapp in fat and lungs and the Kp in muscle for the Vapp of all other organs/tissues. The two sets of estimates of Vdss were compared by linear regression. The same calculations were performed for acidic drugs, except that muscle Kp was used also for the lungs. Distribution to fat and muscle accounted for 84% (61–91%) (median and range) of the total estimated Vdss of the basic drugs (n = 17). The regressions between Kp in organs/tissues and muscle Kp were statistically significant except in the case of liver. For acidic drugs (n = 18), distribution to fat and muscle accounted for 65% (42–92%) of Vdss, and the regressions of Kp were significant for all organs/tissues except kidney and bone. For both types of drugs, correlations between organ/tissue Kp values and Kp in fat were generally worse. There were excellent linear correlations between Vdss calculated by means of only two Kp values and the originally calculated Vdss (r2 ≥ 0.99 for both basic and acidic drugs; slopes were not significantly different from unity). Thus, initial estimation of the Vdss of a new drug can normally be based on only two Kp values, those of muscle and fat. The muscle Kp can be used to represent all lean tissues, including the residual “carcass”, with the exception that fat Kp can be used for distribution of basic drugs to lungs.
The quantification of citral in lemongrass and lemon oils by near-infrared spectroscopy
Authors: Wilson Nicola D , Ivanova Maria S , Watt Robert A , Moffat Anthony C
Published: October 2002

Previous work has demonstrated the capability of near-infrared (NIR) spectroscopy to determine the cineole content (not less than 70% w/w) of eucalyptus oil with an accuracy comparable with that of the British Pharmacopoeia (BP) assay method. The aim of the present study was to determine if the same method was capable of quantifying other chemical constituents at similar levels in essential oils and also to ascertain if NIR spectroscopy can accurately quantify compounds present at much lower levels in essential oils. Lemongrass oil contains citral at concentrations of approximately 65–85% w/w, and lemon oil contains citral at a concentration of approximately 2–5% w/w. A total of 26 samples of pure lemongrass oil and 35 samples of pure lemon oil (both including samples that were “spiked” with citral to increase the calibration range) were scanned on the FOSS NIRSystems 6500 Rapid Content Sampler using a reflectance vessel as sample presentation method. The reference method for both types of oil was the BP monograph titration assay for the citral content of lemon oil and calibrations were constructed using these reference data. For the lemongrass oils, the mean accuracy was found to be 1.00% or less and the mean bias was 0.09% or less. For the lemon oils, the mean accuracy was found to be 4.28% or less and the mean bias was −0.71% or less. The NIR method developed was rapid, simple and non-destructive and may prove beneficial for the accurate determination of the citral content of lemongrass oils and for the approximate citral content of lemon oils.
The influence of lithium on the antidiuretic effect of desmopressin
Authors: Callréus Torbjörn , Holmquist Ing-Britt , Lundin Stefan , Höglund Peter
Published: October 2002

The objective of this study was to investigate the graded influence from lithium on the antidiuretic effects of desmopressin. Eight healthy male subjects participated in this open, randomised cross-over study with two periods comprising 6 days each. For each subject, one of the study days (6th day) was preceded by a period of lithium treatment. On the study days the subjects were orally water loaded to achieve a state of overhydration with a high urine flow rate. When a steady-state diuresis was achieved after approximately 2 h, 0.396 μg of desmopressin was administered intravenously as a bolus injection. An indirect-response model, where desmopressin was assumed to inhibit the elimination of response, was fitted to the urine osmolarity data. The effects of the independent variables, Uflow (baseline) (baseline urine flow rate), R0 (baseline osmolarity) and serum lithium concentration, on IC50 (concentration producing 50% of the maximum inhibition) could be expressed by multiple linear regression. In conclusion, we found that an indirect-response model can be a useful tool in investigating and describing the pharmacodynamic interaction between drugs, in this particular case, between lithium and desmopressin.
Simultaneous detection of monohydroxybenzo[a]pyrene positional isomers by reversed‐phase liquid chromatography coupled to electrospray ionization mass spectrometry
Authors: Sasaki Hideki , Yonekubo Jun , Kanai Michiko , Toriba Akira , Kizu Ryoichi , Hayakawa Kazuichi
Published: October 2002

A liquid chromatographic (LC) method has been developed for the separation of 11 monohydroxybenzo[a]pyrenes (OH BaPs) positional isomers, and for their detection using electrospray ionization mass spectrometry (ESI‐MS). All OH BaPs isomers were separated on an octadecylsilyl (C18)‐bonded amorphous organosilica column utilizing gradient elution with acetonitrile–water and triethylamine (TEA) at pH 11.0 and determined by MS, except 2‐ and 8‐OH BaPs which were coeluted. The lower detection limits were in the range from 1.6 µg/L for 12‐OH BaP to 12 µg/L for 5‐OH BaP without any sample enrichment. The relative standard deviations of area response were in the range from 1.8% (9‐OH BaP) to 4.9% (12‐OH BaP) except for 9.4% (7‐OH BaP). The developed method was successfully applied to incubation mixtures of BaP and CYP1A1/epoxide hydrolase. This method identified 1‐, 3‐ and 9‐OH BaPs as the major metabolites, and 2‐ (and/or 8‐) and 12‐OH BaPs as the minor metabolites in the incubation mixture. Copyright © 2002 John Wiley & Sons, Ltd.