bluuebunny/crossref_metadata_2025 huggingface dataset:
The spatiotemporal expression of TGF‐β1 and its receptors during periosteal chondrogenesis in vitro
Authors: Mizuta Hiroshi , Sanyal Arunik , Fukumoto Takumi , Fitzsimmons James S. , Matsui Nobuzo , Bolander Mark E. , Oursler Merry Jo , O'Driscoll Shawn W.
Published: October 2002

Transforming growth factor‐β1 (TGF‐β1) has been shown to stimulate chondrogenesis in periosteal explants cultured in agarose suspension. TGF‐βs exert their cellular effects through a heteromeric cell membrane receptor complex consisting of TGF‐β type I and type II receptors. In this study, the spatial and temporal expressions of the type I receptor (TβR‐I), type II receptor (TβR‐II) and endogenous TGF‐β1 in periosteal explants cultured in vitro were examined using reverse transcription polymerase chain reaction (RT‐TCR) and immunohistochemistry. The temporal changes in the expression of the TβR‐I and TβR‐II mRNAs correlated with that of TGF‐β1. Exogenous administration of TGF‐β1 upregulated the expression of both receptors and of the TGF‐β1 ligand in a biphasic pattern. The earlier peak of upregulation was observed at 7 days in culture. A later peak of upregulation was seen at 42 days, at which time cartilage formation reached a maximum. Immunohistochemical studies demonstrated co‐localization and TβR‐II simultaneously among the same cells expressing TGF‐β1. TGF‐β1 treatment increased the expression of TGF‐β1, I and TβR‐II in mesenchymal cells in the cambium layer at 7 days in culture. Small round chondrocytes showed widely distributed immunoreactivity of TGF‐β1, TβR‐I and TβR‐II in the 42‐day explants treated with TGF‐β1. These observations support the hypothesis that TGF‐β1 regulates the initiation and formation of cartilage during periosteal chondrogenesis. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The effect of rotator cuff tears on reaction forces at the glenohumeral joint
Authors: Parsons I. M. , Apreleva Maria , Fu Freddie H. , Woo Savio L.‐Y.
Published: October 2002

The rotator cuff muscles maintain glenohumeral stability by compressing the humeral head into the glenoid. Disruption of the rotator cuff compromises concavity compression and can directly affect the loads on the glenohumeral joint. The purpose of this study was to quantify the effect of rotator cuff tears on the magnitude and direction of glenohumeral joint reaction forces during active shoulder abduction in the scapular plane using nine cadaveric upper extremities. Motion of the full upper extremity was simulated using a dynamic shoulder testing apparatus. Glenohumeral joint reaction forces were measured by a universal force–moment sensor. Five conditions of rotator cuff tears were tested: Intact, Incomplete Supraspinatus Tear, Complete Supraspinatus Tear, Supraspinatusl Infraspinatus Tear, and Global Tear. Reaction forces at the glenohumeral joint were found to steadily increase throughout abduction and peaked at maximum abduction for all conditions tested. There were no significant differences in reaction force magnitude for the intact condition (337 ± 88 N) or those involving an isolated incomplete tear (296 ± 83 N) or complete tear (300 ± 85 N) of the supraspinatus tendon. Extension of tears beyond the supraspinatus tendon into the anterior and posterior aspect of the rotator cuff led to a significant decrease in the magnitude of joint reaction force (126 ± 31 N). Similarly, such tears resulted in a significant change in the direction of the reaction force at the glenohumeral joint. These results suggest that joint reaction forces are significantly affected by the integrity of the rotator cuff, specifically, by the transverse force couple formed by the anterior and posterior aspects of the cuff. The quantitative data obtained in this study on the effect of rotator cuff tears on magnitude and direction of the reaction force at the glenohumeral joint helps clarify the relationship between joint motion, joint compression and stability. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The localized expression of extracellular matrix components in healing tendon insertion sites: an in situ hybridization study
Authors: Thomopoulos S. , Hattersley G. , Rosen V. , Mertens M. , Galatz L. , Williams G. R. , Soslowsky L. J.
Published: October 2002

The localized expression of a number of extracellular matrix genes was evaluated over time in a novel rat rotator cuff injury model. The supraspinatus tendons of rats were severed at the bony insertion and repaired surgically. The healing response was evaluated at 1, 2, 4, and 8 weeks post‐injury using histologic and in situ hybridization techniques. Expression patterns of collagens (I, II, III, IX, X, XII), proteoglycans (decorin, aggrecan, versican, biglycan, fibromodulin), and other extracellular matrix proteins (elastin, osteocalcin, alkaline phosphatase) were evaluated at the healing tendon to bone insertion site. Histologic results indicate a poor healing response to the injury, with only partial recreation of the insertion site by 8 weeks. In situ hybridization results indicate a specific pattern of genes expressed in each zone of the insertion site (i.e., tendon, fibrocartilage, mineralized cartilage, bone). Overall, expression of collagen types I and XII, aggrecan, and biglycan was increased, while expression of collagen type X and decorin was decreased. Expression of collagen type I, collagen type XII, and biglycan decreased over time, but remained above normal at 8 weeks. Results indicate that the rat supraspinatus tendon is ineffective in recreating the original insertion site, even at 8 weeks post‐injury, in the absence of biological or biomechanical enhancements. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
A novel bisphosphonate inhibits inflammatory bone resorption in a rat osteolysis model with continuous infusion of polyethylene particles
Authors: Iwase Miho , Kim Kang Jung , Kobayashi Yoshiro , Itoh Masatoshi , Itoh Tatsuo
Published: October 2002

This study examined the inhibitory effect of a new bisphosphonate (TRK‐530) on wear debris‐mediated bone resorption in a rat osteolysis model involving continuous infusion of high density polyethylene (HDPE) particles. TRK‐530 (TRK) is a novel synthetic bisphosphonate that has been shown to decrease the level of tumor necrosis factor alpha (TNF‐α) in the bone marrow of rats with adjuvant arthritis. Forty Wistar rats were randomized to two groups (n = 20 each). In each rat, a Kirshner (K) wire was inserted into the femur and HDPE particles were continuously infused into the knee joint. Thereafter, the animals were subcutaneously injected with saline (control group) or 1 mg/kg of TRK (TRK group) every second day, and were sacrificed at 4 or 8 weeks after surgery. Radiographs obtained at the time of sacrifice were evaluated for periprosthetic osteolysis. We also examined the thickness of the reactive membrane as well as the number of osteoclast‐like cells around the K‐wire. In addition, we examined the expression of genes for bone‐resorbing cytokines in the reactive membrane. Radiographic peri‐implant osteolysis was more frequent in the control group compared with the TRK group at each time of assessment (p < 0.01). The interfacial membrane was significantly thinner in the TRK group compared with the control group (p < 0.01) and the average number of osteoclast‐like cells around the K‐wire was significantly fewer in the TRK group (p < 0.01). In addition, the expression of interleukin 1‐alpha messenger ribonucleic acid (IL‐1α mRNA) and TNF‐α mRNA was suppressed in the TRK group at each time of assessment. We conclude that the TRK can inhibit the formation of inflammatory peri‐implant osteolysis induced by HDPE particles. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Collagen‐targeted BMP3 fusion proteins arrayed on collagen matrices or porous ceramics impregnated with Type I collagen enhance osteogenesis in a rat cranial defect model
Authors: Han Bo , Perelman Natalya , Tang Baowei , Hall Fredrick , Shors Edwin C. , Nimni Marcel E.
Published: October 2002

Bone morphogenetic protein 3 (BMP3) is a potent osteoinductive growth factor belonging to the TGF‐β superfamily. In this study, we engineered a recombinant BMP3 protein to include an auxiliary collagen‐targeting domain derived from von Willebrand coagulation factor (vWF). The collagen‐targeted BMP3 fusion protein (rhBMP3‐C) was expressed in E. coli, purified from bacterial inclusion bodies, renatured under controlled redox conditions, and assayed for biological activity in vitro and in vivo. The renatured rhBMP3‐C fusion protein bound tightly to collagen matrices and inhibited DNA synthesis in normal rat calvaria cells and in two out of three human osteosarcoma cell lines tested. Alkaline phosphatase activity was increased in rat calvarial cells and was decreased in osteosarcoma cells in vitro in a dose‐dependent manner. Collagen sponges impregnated with rhBMP3‐C and implanted subcutaneously in Fischer‐344 rats induced dose‐dependent dystrophic calcification of the collagen matrix, with no evidence of ectopic bone formation. However, local injection of rhBMP3‐C infused in a collagen suspension induced new bone formation on the periosteal surface of rat calvaria. Finally, in a rat cranial defect model, surgical implantation of rhBMP3‐C arrayed on either collagen sponges or on porous ceramics coated with Type I collagen exhibited marked osteoinductive properties. Taken together, these results demonstrate the feasibility of engineering and manufacturing targeted‐BMPs which exhibit an integral gain‐of‐function that may be exploited to therapeutic advantage in (i) the enhancement of effective local concentrations, (ii) the prevention of systemic biodistribution and side effects, and (iii) the design of improved osteoinductive matrices. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The effect of pulsed electromagnetic fields on the osteointegration of hydroxyapatite implants in cancellous bone: a morphologic and microstructural in vivo study
Authors: Fini Milena , Cadossi Ruggero , Canè Valerio , Cavani Francesco , Giavaresi Gianluca , Krajewski Adriano , Martini Lucia , Aldini Nicolò Nicoli , Ravaglioli Antonio , Rimondini Lia , Torricelli Paola , Giardino Roberto
Published: October 2002

Effects of pulsed electromagnetic fields (PEMFs, 75 Hz, 1.6 mT) were investigated in 12 rabbits after placing hydroxyapatite (HA) implants in their femoral condyles. Six animals were stimulated with PEMFs for three consecutive weeks, 6 h/day, while the remaining animals were sham‐treated (Control Group). Rabbits were sacrificed at 3 and 6 weeks (after a 3‐week non‐stimulation period) for histomorphometric analysis and microhardness testing (at 200, 500, 1000, 2000 μm from the implant) around the implants around the implants. Histomorphometric analysis did not highlight any significant changes. On the contrary, there were statistically significant differences between the effects produced by PEMFs and Control Groups (F = 149.70, p < 0.0005) on the Affinity Index results, as well as by the experimental time of 6 and 3 weeks (F = 17.12, p = 0.001) on the same results. In PEMF‐stimulated animals the microhardness (HV) values measured in trabecular bone at a distance of 200 and 500 μm from the implants, were significantly higher with respect to controls. At 6 weeks, HV values at the bone‐implant interface in PEMF‐stimulated animals were not significantly different with respect to normal bone, while they remained significantly lower in control animals. Both morphological and structural results demonstrated a positive therapeutic effect of PEMFs in accelerating HA osteointegration in trabecular bone. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Detection and analysis of cartilage degeneration by spatially resolved streaming potentials
Authors: Légaré A. , Garon M. , Guardo R. , Savard P. , Poole A. R. , Buschmann M. D.
Published: October 2002

Cartilage molecular changes in osteoarthritis are most commonly related to the degradation and loss of proteoglycan and collagen fibrils of the extracellular matrix, which directly influence tissue stiffness and compression‐generated streaming potentials. In this study, we evaluated the potential of a new technique, spatially resolved mapping of streaming potentials, to non‐destructively indicate cartilage health or degeneration. Matched pairs of bovine cartilage/bone explant disks were cultured for 11 days in a serum free medium with and without interleukin‐1α (IL‐1α). The electromechanical properties (static stiffness, dynamic stiffness and streaming potentials) of cartilage disks were measured during unconfined compression using a mechanical tester coupled with a linear array of eight 50 μm diameter platinum‐iridium microelectrodes. After 11 days of culture, the proteoglycan content of IL‐1α treated disks was significantly reduced and the denatured and cleaved collagen content was increased compared to control disks. These biochemical alterations were concomitant with the reductions in the amplitudes of the static stiffness, the dynamic stiffness and the streaming potential profile as well as changes in the shape of the streaming potential profile. We found that spatial mapping of streaming potentials presents several advantages for the development of a clinical instrument to evaluate the degeneration of articular cartilage. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
ATP induces proliferation of retinal cells in culture via activation of PKC and extracellular signal‐regulated kinase cascade
Authors: Sanches Glauco , de Alencar Laura Sá , Ventura Ana Lucia Marques
Published: October 2002

Both ATP and acetylcholine can induce the mobilization of intracellular calcium in the early developing chick embryo retina, a response that decreases during retinal development. In this study, the effects of these transmitters on the turnover of phosphoinositides and proliferation of developing retinal cells in culture were characterized. While ATP, UTP or carbachol were able to induce a >400% accumulation of phosphoinositides in retinal cell cultures, only ATP promoted a dose‐dependent increase in [3H]‐thymidine incorporation in cultured cells (EC50=8.6 μM), a response that was inhibited by the P2 receptor antagonist pyridoxal‐phosphate‐6‐azophenyl‐2′,4′‐disulfonic acid (PPADS) (0.1 or 0.25 mM). ADP, but not UTP or adenosine, also stimulated the proliferation of retinal cells (EC50=5.8 μM), indicating that activation of P2Y1 receptors mediates the proliferative response of retinal cells to ATP. The mitogenic effect of ATP was completely prevented by the PKC inhibitor chelerythrine chloride (0.5 μM) and the phospholipase C (PLC) inhibitor U73122 (0.5 μM). PD 98059 (25 or 50 μM), an inhibitor of the activation of extracellular signal‐regulated kinases (ERKs) also blocked the increase in [3H]‐thymidine incorporation induced by ATP. Moreover, the effect of ATP was pronounced in cultures obtained from retinas at embryonic days 6–8, but not at day 9. Since Müller and bipolar cells are the predominant cell types that proliferate at these embryonic stages, our data suggest that ATP, through activation of P2Y1 receptors coupled to phospholipase C, PKC and MAP kinases, affects DNA synthesis in one or both of these cell types in culture.
Beyond Manichean economics: foreign direct investment and growth in the transition from socialism
Authors: King L.P. , Váradi B.
Published: October 2002

Using case study data from Hungary, this paper explores the developmental impact of foreign direct investment (FDI) in transition economies. A review of the debate on FDI is conducted by exploring the political discourse surrounding this issue in Hungary. The numerous and competitive purported mechanisms linking FDI with either economic growth or stagnation are used to analyze the case studies. This analysis reveals that FDI can take very different forms, with very different economic consequences. On balance, the evidence suggests that foreign direct investment has been very positive for the Hungarian economy. However, there exists the possibility that the current success of foreign owned firms will lead to socially detrimental market concentration or even hinder future growth.
Explaining regional economic policies in China: interest groups, institutions, and identities
Authors: Horowitz S. , Marsh C.
Published: October 2002

What explains variation in investment climates across China's provinces and urban autonomous regions? Three main explanations are considered: variation in the character and size of economic interest groups, in central government policies, and in pre-communist provincial identities and traditions. There is statistical and anecdotal support for the interest group and provincial identity factors. On the other hand, there is little evidence that variation in central government policy has had much effect. Future work should refine statistical tests and case studies to better understand the joint influence of interest group pressures and provincial identities.
Influence of progressive renal dysfunction in chronic heart failure
Authors: Maxwell A. Peter , Ong Hean Y. , Nicholls D. Paul
Published: October 2002

Chronic heart failure (CHF) is often associated with impaired renal function due to hypoperfusion. Such patients are very sensitive to changes in renal perfusion pressure, and may develop acute tubular necrosis if the pressure falls too far. The situation is complicated by the use of diuretics, ACE inhibitors and spironolactone, all of which may affect renal function and potassium balance. Chronic renal failure (CRF) may also be associated with fluid overload. Anaemia and hypertension in CRF contribute to the development of left ventricular hypertrophy (LVH), which carries a poor prognosis, so correction of these factors is important.
Addition of candesartan to angiotensin converting enzyme inhibitor therapy in patients with chronic heart failure does not reduce levels of oxidative stress
Authors: Ellis Gethin R. , Nightingale Angus K. , Blackman Daniel J. , Anderson Richard A. , Mumford Catherine , Timmins Graham , Lang Derek , Jackson Simon K. , Penney Michael D. , Lewis Malcolm J. , Frenneaux Michael P. , Morris‐Thurgood Jayne
Published: October 2002

Background:

Angiotensin II exerts a number of harmful effects in patients with chronic heart failure (CHF) and, through an increase in oxidative stress, is thought to be critical in the development of endothelial dysfunction. Angiotensin II may be elevated in CHF despite treatment with angiotensin converting enzyme (ACE) inhibitors, producing a rationale for adjunctive angiotensin receptor blockade. We investigated whether the addition of angiotensin antagonism to ACE inhibition would reduce oxidative stress and improve endothelial function and exercise tolerance in patients with chronic heart failure.

Methods and results:

Twenty‐eight heart failure patients, who were on stable ACE inhibitor therapy, were randomised to receive adjunctive therapy with candesartan or placebo. Plasma lipid‐derived free radicals, TBARS and neutrophil O2‐generation, markers of oxidative stress, were measured in venous blood. Arterial endothelial function was assessed as the response of the brachial artery to flow‐related shear stress. Exercise capacity was determined by cardiopulmonary exercise testing. Compared with placebo, candesartan had no effect on changes in lipid derived free radicals (−0.1±1.2 vs. −0.1±1.0 units, respectively, P ‐ NS), TBARS (−2.2±1.1 vs. −2.6±2.2 μmol/l, respectively, P ‐ NS) or neutrophil O2‐generating capacity (−7.3±5.1 vs. −8.4±7.9 mV/5×105 neutrophils, respectively, P ‐ NS). There was no effect on changes in brachial artery flow‐mediated dilatation (0.5±1.0 vs. 0.8±1.3%, respectively, P ‐ NS) nor peak VO2 (1.6±0.7 ml/kg per min vs. 1.8±0.6 ml/kg per min; P ‐ NS).

Conclusion:

The addition of the candesartan to ACE inhibitor therapy had no effect on oxidative stress and did not improve endothelial function or exercise capacity in patients with CHF.
Approaches to statistical analysis of repeated echocardiographic measurements after myocardial infarction and its relation to heart failure: Application of a random‐effects model
Authors: de Kam Pieter‐Jan , Voors Adriaan A. , Brouwer Jan , St John Sutton Martin , van Gilst Wiek H.
Published: October 2002

Background:

Extensive left ventricular (LV) dilatation after myocardial infarction (MI) is associated with increased heart failure risk.

Aims:

To investigate whether the power to demonstrate the relation between LV dilatation and heart failure depends on the method applied to predict LV dilatation after MI. Methods: A random‐effects model and ANOVA model for repeated measurements (MANOVA) were applied to predict LV volume index during 1 year for 298 post‐MI patients. Spearman correlation coefficients (r) were calculated and Cox regression analysis was used to calculate risk ratio's (RR).

Results:

LV volume indices were more accurately predicted by a random‐effects model than by a MANOVA model (systolic/diastolic respectively r‐0.93/0.91 vs. r‐0.67/0.64). Furthermore, patients with high LV volume index as predicted by the random‐effects model, had significantly increased heart failure risk (systolic RR 2.04 (95% CI: 1.31 to 3.17; P‐0.001), diastolic RR 1.80 (95% CI: 1.16 to 2.78; P‐0.007). Using the same data, MANOVA failed to demonstrate this relation significantly (systolic RR 1.77 (95% CI: 0.79 to 3.98; P‐0.16), diastolic RR 1.49 (95% CI: 0.68 to 3.30; P‐0.31).

Conclusion:

When analyzing repeated measurement data, random‐effect models are more powerful in detecting clinical relations than are MANOVA models, especially in the presence of missing values.
How patients with heart failure are managed in Portugal
Authors: Fonseca Cândida , Ceia Fátima , Brito Dulce , Madeira Hugo
Published: October 2002

The prevalence of heart failure is increasing all over the world. It is a common and growing public health problem in Portugal as in many other European countries. This article provides a review of health service organization and current heart failure management in Portugal, discusses primary care and ward practices in different hospitals and reports on the use of proven standard therapies for the treatment of heart failure in the community. Despite major advances in diagnosis and treatment, heart failure is only satisfactorily managed. Furthermore efforts are necessary before the beneficial effects observed in trials have a real impact in clinical practice. A broader view and priority for the management of this syndrome on a national level are needed to improve the quality of heart failure care in Portugal.
Carvedilol does not alter the insulin sensitivity in patients with congestive heart failure
Authors: Refsgaard Jens , Thomsen Claus , Andreasen Frederik , Gøtzsche Ole
Published: October 2002

Background

Congestive heart failure (CHF) has previously been shown to be associated with insulin resistance and hyperinsulinemia. A beneficial effect of the non‐selective β‐blocker carvedilol has been demonstrated in patients with CHF. However, whether the drug affects the insulin sensitivity (Si) is unknown.

Aims

To investigate whether treatment with carvedilol alters the Si in patients with CHF during a prospective, double‐blinded, placebo‐controlled study. Methods and results: The patients were randomized to receive either carvedilol (n‐29) or matched placebo (n‐17). Insulin and glucose responses were measured during a 0.3 g/kg intravenous glucose tolerance test, and Si was calculated according to Bergman's Minimal Model. Baseline Si values correlated significantly with body mass index (r‐−0.42, P‐0.002), plasma urate (r‐−0.42, P‐0.002), plasma HDL‐cholesterol (r‐0.39, P‐0.003), maximal oxygen uptake (r‐0.35, P‐0.009), plasma triglycerides (r‐−0.34, P‐0.01) and weight (r‐−0.29, P‐0.03). During the study the insulin sensitivity was unchanged in the carvedilol group compared with placebo (2.63±1.45 to 2.38±1.64 vs. 2.81±2.36 to 2.48±1.84×10−4 min−1/mU1−1, P‐0.83).

Conclusion

Additional treatment with carvedilol is neutral with regard to influence the insulin sensitivity in patients with mild to moderate CHF.
The effectiveness and relative effectiveness of intravenous inotropic drugs acting through the adrenergic pathway in patients with heart failure—a meta‐regression analysis
Authors: Thackray Simon , Easthaugh Joanne , Freemantle Nick , Cleland John G.F.
Published: October 2002

Aims

To review systematically the use of intravenous (IV) inotropic agents acting through the adrenergic signalling pathway, compared with placebo or an active agent, in patients with heart failure.

Methods

Studies investigating the use of intravenous inotropes in patients with heart failure published between 1966 and 2000 were identified using MEDLINE, the Cochrane register and Embase databases. Reference lists from relevant papers and reviews were hand searched for further papers. In total, 21 trials, that included 632 patients receiving IV inotropic drugs, placebo or non‐treatment control, were identified. Drugs of the following classes were included, the β‐agonists; dobutamine, high‐dose (>2.5 μg/kg/min) dopamine, dopexamine and the phosphodiesterase (PDE) inhibitors; amrinone, milrinone, enoximone and toborinone. Sixteen trials (474 patients) contributed data from acute invasive haemodynamic studies of symptomatically severe heart failure. Five trials (158 patients) were based on intermittent inotropic therapy in an outpatient context.

Results

With few exceptions, trials of intravenous inotropic agents were small and often failed to report clinically important outcomes. Compared to placebo, intravenous inotropic agents acting through the adrenergic system tended to increase mortality (odds ratio 1.50 (95% CI‐0.51 to 3.92) but this did not reach significance and insufficient data were available to determine whether symptoms improved. There appeared to be little difference in the effect of beta‐agonists compared to PDE inhibitors on patient outcomes but this could be attributed to the paucity of data.

Conclusions

Intravenous inotropic agents acting through the adrenergic pathway are often used in patients with worsening heart failure to achieve arbitrary haemodynamic targets. Our analyses show that there is very little evidence that such treatment improves symptoms or patient outcomes and may not be safe. This highlights the need for further well designed randomised clinical trials.
Risk, Activity Modularization, Sourcing, and Economic Geography
Authors: Penfold Robert B
Published: October 2002

Economic geography is fundamentally concerned with describing spatial variation in the economic landscape and explaining the processes through which this geography takes form. Firms are the primary units through which these processes operate. I reinterpret portfolio theory to provide a novel way of explaining and modeling the spatial implications of control structures and organizational decisions within and between firms. In this paper, I argue that each activity of the firm is like an asset with an expected rate of return and a level of risk. Firms implement spatial strategies to manage risk that trade profits for reductions in risk. These strategies encourage geographic switching and perpetuate regional disequilibria in production technology and employment. Risk management and the structure of control in a production chain explain the geographic distribution of economic activity better than do transaction costs, flexible specialization, or agglomeration economies.
Breaking out of the ‘Isolated State’: Views on the Status and Future of Regional Science from a European Border Region
Authors: Kramsch Olivier , Boekema Frans
Published: October 2002

Against the backdrop of a perceived ‘crisis’ within the field of Anglo-American regional science, in this paper we offer a brief overview of the early engagement of regional science with the regional concept, while placing its theoretical formulations within the wider sociohistorical context of the Cold War period and the rise of positivist social science. With regard to the development of regional science as a field of enquiry with its own theoretical and empirical postulates, attention focuses on what David Harvey has referred to as a “utopianism of spatial form”, defined by the idea that spatial constructs can serve to control social processes in positive ways, thus using space to evade historical change. In building bridges from the Isardian promise of the past of regional science to its multiple futures, we suggest that the field today may break out of its current ‘isolated state’ by entering into creative dialogue with the metaphors animating three research streams: (1) an ‘analytical turn’ in Marxist economic geography; (2) a Marshallian ‘New Regionalism’; and (3) a ‘cultural turn’ perceived to be occurring within the field of radical political economy. Each stream, addressed here as a successive and broader departure from the more orthodox “utopianism of spatial form” in spatial and regional science, is briefly surveyed in turn. Drawing on the metaphor of borders and border-lands, we conclude by arguing that rather than view each research strand as an ‘improvement’ on its predecessor they should be viewed as the grounds for a potentially rich cross-fertilization between spatial science and various fields of nonorthodox economics.
Speech Acts and Space(s): Language Pragmatics and the Discursive Constitution of the Social
Authors: Zierhofer Wolfgang
Published: October 2002

By referring to language-pragmatic versions of action theory, I attempt in this paper to introduce a perspective which overcomes a series of modernistic legacies of earlier action theories in human geography. Such a development allows a nonessentialist stance while preserving the conceptual richness and consistency of action theory. The concept of speech acts will be interpreted as a blueprint for the analysis of interactions in general—not only human communications but also those involving nonhuman entities and physical conditions—and is a perspective that is particularly attractive for human geography. However, one of the consequences is that the notion of space and its role for the identity of the discipline need to be reconsidered.
Regional Variation in Family Support for the Elderly in China: A Geodevelopmental Perspective
Authors: Lin Ge
Published: October 2002

The author examines the impact of rapid social change and economic development on family support for older parents in contemporary urban China. Based on the 1992 Survey on China's Support Systems for the Elderly, the author uses three levels of economic development as proxies for developmental stages in a study carried out from a geodevelopmental perspective. It is found that intergenerational support in urban China is persistent as far as instrumental support is concerned, and that the level of support follows a U-shaped pattern along the axis of economic development. It is in the mid-developed urban areas that intergenerational support seems the weakest. If the pattern from the less-developed to the developed urban areas reflects a time path, then the suggested trajectory will not lead to a convergence with the old-age support system found in the West. The author concludes that, although some aspects of economic support for the elderly will likely be consistent with modernization theory, the old-age support system in China is, on the whole, likely to diverge from the path seen in the West.
Behind the Web Store: The Organisational and Spatial Evolution of Multichannel Retailing in Toronto
Authors: Currah Andrew
Published: October 2002

In this paper I address two issues of general relevance to contemporary debates in economic geography: first, the organisational and spatial implications of new information technologies for the economic landscape; and, second, the enduring role of place to digital capitalism. Specifically, I examine the organisational evolution of multichannel retailing in Toronto from a geographical perspective. Bricks-and-mortar retailers are increasingly pursuing a multichannel strategy by operating an Internet-based web store alongside the existing network of physical retail outlets. I therefore evaluate the organisational implications of the adoption of business-to-consumer e-commerce (e-tailing) technology for six Canadian bricks-and-mortar retailers based in Toronto and assess how the associated changes in business structure have been inscribed upon the urban landscape. The argument is developed in three sections. First, I discuss how the formula for competitive advantage in the new (r)etail markets of the developed world has shifted from a pure play to a multichannel organisational paradigm. Second, I provide a background to the development of Canadian e-commerce and an overview of the empirical methodologies employed during the research. Third, the focus of the paper moves ‘behind the web store’ to spatialise the physical places that constitute the fulfilment infrastructure of e-tailing as sequentially linked stages in Internet commodity chains. I evaluate the impact of the Internet commodity chain upon the geographical organisation of each retailer, and, in particular, consider whether the unique logistical requirements of e-tailing have stimulated spatial processes of disintermediation and reintermediation. It is argued that, when read through the lens of Toronto, e-tailing has incurred limited organisational disruption and is characterised by a distinctive geography of integration between online and offline retailing services within the urban space of the city. I conclude the paper by contextualising the findings within themes for conceptual debate in economic geography.
Chain-Model Shape-Pattern Schemata
Authors: Egli Richard , Stewart Neil F
Published: October 2002

A shape-pattern schema is an organized body of knowledge about spatial relationships between shapes which describes the patterns, syntactic structure, and the characteristics of shape patterns. In this paper we show how such schema can be represented by means of chain models. We also show the advantage of this approach (relative to the previously suggested tree representations) for patterns with certain natural symmetries. To do this, we describe an example, and discuss its implementation by means of the application procedural interface of our system. Because the chain-model formulation subsumes the tree representation as a special case, the chain-model approach can also be used wherever the tree representation would be appropriate.
Determination of Thresholds of Visual Impact: The Case of Wind Turbines
Authors: Bishop Ian D
Published: October 2002

Visual impact assessment using GIS (geographical information system) based viewshed mapping is commonly employed on major projects. However, there is typically little analysis of the possible range of impact based on the size of the introduced landscape element, its contrast with the surroundings, or the effect of typical levels of atmospheric scattering on the perceived contrast. A landscape element which is increasingly the subject of aesthetic scrutiny and visual analysis is the wind-energy turbine or—when installed in large numbers—the wind farm. I take the wind turbine as my subject partly because of its recent significance and also because, as a moving element, it is a special case. I report an Internet-based experiment to determine the relative perceived size of a turbine, image analysis to determine its typical contrast level, and the effect of atmospheric scattering on this contrast. With these three factors and equations derived in an earlier study, estimates are made for the probability of turbine detection, recognition, and visual impact at distances up to 30 km.
On Regional Systems of Innovation: Illustrations from the West Midlands
Authors: Freel Mark S
Published: October 2002

The data presented here were collected as one component of a project aimed at developing a regional innovation strategy for the West Midlands region of England. Like most regional policy measures the regional innovation strategy programme was driven by concern over widening economic performance differences between (European) regions and was intended as a means of closing observed cohesion and technology gaps [Commission of the European Communities, 1998 Reinforcing Cohesion and Competitiveness Through Research, Technological Development and Innovation COM (98) 275]. More importantly, however, the notion that distinct regional innovation strategies may be developed in each assisted region is premised on a belief in underlying idiosyncrasies in regional resource endowments, competencies, institutional infrastructure, industry, and governance. In other words, it is premised on the belief that there exist, or may exist with sufficient encouragement or facilitation, distinct regional innovation systems within Europe (Thomas K, 2000 Regional Studies34 190–198). Accordingly, my purpose in the current paper is to outline the basic precepts underpinning a systemic approach to innovation, generally, and a regional systemic approach, specifically. Thereafter, an attempt is made to map partially the existence, or indeed absence, of a West Midlands regional innovation system, proxied by available firm-level data, and to comment on the appropriateness of regional systems of innovation as units of analyses.
Census Counts and Apportionment: The Politics of Representation in the United States
Authors: Johnston Ron
Published: October 2002

Census counts are used in the United States as the basis for a derived ‘apportionment count’, which is employed by the President to allocate seats in the House of Representatives across the 50 States. This apportionment count includes not only those individuals recorded by the census (either by direct count or by imputation) as usually resident in each State but in addition federal employees, including military personnel, and their dependents. This practice has been challenged on several occasions in the courts, most recently by the State of Utah, which claimed that it was denied a fourth seat in the House for the period 2002 – 12 as a consequence. Its claim was denied, for reasons which are discussed here and which throw further light (following Hannah, 2001 Environment and Planning D: Society and Space19 515 – 534) on the social constructions involved in the conduct and use of censuses.
Re-Claiming Place: The Millennium Forest, Borgie, North Sutherland, Scotland
Authors: Mackenzie A Fiona D
Published: October 2002

In this paper I explore the metaphorical and material significance of the Millennium Forest at Borgie in the context of an emerging movement for the collective purchase of private estates in the crofting areas of Scotland. My argument focuses, first, on the means whereby the Forest, as visual art, is constituted as a site through which what Edward Said calls a ‘culture of resistance’ is mobilised and through which an inclusive sense of belonging to place is imagined. Second, I connect the poetics of resistance of the Forest with the politics of territorial land claims of the North Sutherland Community Forestry Trust, whose objective is to reverse ongoing processes of dispossession through the collective ownership and management of the 3000–hectare Borgie Forest which the one-hectare Millennium Forest borders.
Shopping, Space, and Practice
Authors: Gregson Nicky , Crewe Louise , Brooks Kate
Published: October 2002

In this paper we address questions of ‘shopping as practised’ and its relation to shopping space. We argue that modes of shopping, which comprise distinctive sets of shopping practices involving relations to goods (purchases), relations of looking (and seeing), the place of shopping in the rhythms of everyday life, and the socialities of shopping, are used to invest meaning in particular types of shopping space and to produce individual, accumulated, personalised shopping geographies that weave together particular locations and generic spaces. Furthermore, modes of shopping are shown to require specific sets of knowledge to practise and to relate to specific subject positions, namely necessity and choice. These arguments are developed in relation to charity shops and charity shopping. However, they are shown to have broader implications: specifically they show the relationality of modes of shopping and shopping spaces, and the distinctions between shopping geographies and retail geographies. Theoretically, they suggest that accounts of shopping need to locate meaning in practice; that the meanings of shopping (and the meanings invested in particular shopping spaces) are therefore potentially unstable; and that accounts of the constituting subjects of shopping need to take seriously the spatialities of subjectivities.
Deconcentration by Demolition: Public Housing, Poverty, and Urban Policy
Authors: Crump Jeff
Published: October 2002

During the 1990s, local and federal urban policymakers, neoliberal politicians, and advocates for the poor came to a broad consensus: the geographic concentration of low-income, minority residents in public housing projects located in the inner city constitutes the fundamental problem facing US cities. Accordingly, to solve the problems allegedly associated with the spatial concentration of poverty, public housing, which concentrates low-income people in the inner city, must be demolished and the residents relocated. In this paper I argue that such federal public housing policies are based on a conceptually inadequate understanding of the role of space and of spatial influences on poverty and on the behavior of poor people. The use of spatial metaphors such as the ‘concentration of poverty’ or the ‘deconcentration of the poor’ disguises the social and political processes behind poverty and helps to provide the justification for simplistic spatial solutions to complex social, economic, and political problems.
Factors Contributing to the Implicit Dynamic Quality of Static Abstract Designs
Authors: Locher Paul J , Stappers Pieter Jan
Published: October 2002

Participants rated the dynamic quality of a set of twelve-element nonrepresentational or abstract visual designs each composed of one of four types of triangles or four types of quadrilaterals. We investigated the contribution to the perceived or implicit dynamics of the design of the four factors edge alignment of compositional elements, physical weight distribution about the horizontal axis, activity directions within the designs, and type of compositional element. It was found that edge alignment of elements was the most influential factor contributing to the dynamics both of triangle and of quadrilateral designs. In addition, dynamics was found to be positively correlated with the number of perceived activity directions within both types of stimuli. Triangle designs, but not quadrilateral ones, with greater structural weight above the horizontal axis were rated as more dynamic. Results suggest that implicit dynamics of nonrepresentational designs arises from a percept based on a global spatial analysis of the stimulus characteristics studied.
Latency Correction Explains the Classical Geometrical Illusions
Authors: Changizi Mark A , Widders David M
Published: October 2002

There is a significant delay between the time when light hits the retina and the time of the consequent percept. It has been hypothesized that the visual system attempts to correct for this latency by generating a percept representative of the way the world probably is at the time the percept is elicited, rather than a percept of the recent past. Here we show that such a ‘perceiving the present’ hypothesis explains a number of classical geometrical illusions: the Hering, Orbison, Müller-Lyer, Double Judd, Poggendorff, Corner, and Upside-down-T illusions. Each stimulus is perceived as it would project in the next moment were the observer moving through the scene the stimulus probably represents. We also examine one general class of predictions made by the hypothesis, and report psychophysical experiments confirming the predictions.
Electro‐membrane filtration for the selective isolation of bioactive peptides from an αs2‐casein hydrolysate
Authors: Bargeman Gerrald , Houwing Joukje , Recio Isidra , Koops Geert‐Henk , van der Horst Caroline
Published: October 2002

For the isolation of the ingredients required for functional foods and nutraceuticals generally membrane filtration has too low a selectivity and chromatography is (too) expensive. Electro‐membrane filtration (EMF) seems to be a breakthrough technology for the isolation of charged nutraceutical ingredients from natural sources. EMF combines the separation mechanisms of membrane filtration and electrophoresis. In this study, positively charged peptides with antimicrobial activity were isolated from an αs2‐casein hydrolysate using batch‐wise EMF. αs2‐Casein f(183–207), a peptide with strong antimicrobial activity, predominated in the isolated product and was enriched from 7.5% of the total protein components in the feed to 25% in the permeate product. With conventional membrane diafiltration using the same membrane (GR60PP), isolation of this and other charged bioactive peptides could not be achieved. The economics of EMF are mainly governed by the energy costs and the capital investment, which is affected by the flux of the desired peptide. A maximum average transport rate of αs2‐casein f(183–207) during batch‐wise EMF of 1.2 g/m2 · h was achieved. Results indicate that an increase in the hydrolysate (feed) concentration, the applied potential difference and the conductivity of the permeate and electrode solutions, and a reduction in the conductivity of the feed result in a higher transport rate of αs2‐casein f(183–207). This is in line with the expectation that the transport rate is improved when the concentration, the electrical field strength, or the electrophoretic mobility is increased, provided that the electrophoretic transport predominates. The expected energy consumption of the EMF process per gram of peptide transported was reduced by approximately 50% by applying a low overall potential difference and by processing desalinated hydrolysate. Considerable improvements in transport rate, energy efficiency, and process economics seem to be attainable by additional optimization of the process parameters and the EMF module design. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 599–609, 2002.
Toxicity of terpenes to spores and mycelium of Penicillium digitatum
Authors: Wolken Wout A. M. , Tramper Johannes , van der Werf Mariët J.
Published: October 2002

Spores, although often considered metabolically inert, catalyze a variety of reactions. The use of spores instead of mycelium for bioconversions has several advantages. In this paper, we describe the difference in susceptibility of mycelium and spores against toxic substrates and products. A higher resistance of spores toward the toxic effects of bioconversion substrates and products is an advantage that has not been studied in detail until now. This paper shows that spores of Penicillium digitatum ATCC 201167 are on average over 2.5 times more resistant than mycelium toward the toxicity of substrates, intermediates, and products of the geraniol bioconversion pathway. Furthermore, the higher resistance of spores to citral was shown as an advantage in its biotransformation by P. digitatum. Using three different approaches the toxicity of the compounds were tested. The order of toxicity toward P. digitatum was, starting with the most toxic, citral > nerol/geraniol > geranic acid > methylheptenone ≫ acetaldehyde. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 685–690, 2002.
Molecular characteristics of some commercial high‐molecular‐weight hyaluronans
Authors: Šoltés L. , Mendichi R. , Lath D. , Mach M. , Bakoš D.
Published: October 2002

Commercially available hyaluronan (HA) samples were investigated by the method of size exclusion chromatography (SEC). The fractions eluted from the SEC column were on‐line molecularly characterized by using a multi‐angle laser light scattering (MALLS) photometer. Along with the SEC‐MALLS technique, the high‐molecular‐weight HA biopolymers were (off‐line) analyzed by capillary viscometry. Copyright © 2002 John Wiley & Sons, Ltd.