bluuebunny/crossref_metadata_2025 huggingface dataset:
Does an Integrated Care Pathway enhance the management of diabetic ketoacidosis?
Authors: Waller S. L. , Delaney S. , Strachan M. W. J.
Published: February 2007

Aims  Integrated Care Pathways (ICPs) are management plans that indicate the sequence and timing of the optimal treatment for individuals with a given disorder. The treatment of diabetic ketoacidosis (DKA) before and after the implementation of an ICP in a teaching hospital was examined.

Methods  Twenty‐seven episodes of DKA were identified during the 13‐month control period and 22 in the 13 months following implementation of the ICP. Case notes were reviewed and relevant clinical data extracted.

Results  The introduction of the ICP was associated with a reduction in the time taken to initiate intravenous fluid [45.0 (5–225) min to 37.5 (0–135) min; P = 0.01]. Time taken to initiate insulin infusion was also reduced [60.0 (5–755) min to 37.5 (0–175) min; P = 0.02]. The proportion of patients commenced on intravenous insulin within 60 min increased from 48 to 77% (P = 0.04). In addition, there was a reduction in the prescription of antibiotics (48–18%; P = 0.028) and low molecular weight heparin (59–5%; P < 0.001). Length of stay was not affected.

Conclusion  The ICP significantly improved key areas in the management of DKA, although there remains room for further improvements.
Who Cares about Environmental Stigmas and Does It Matter? A Latent Segmentation Analysis of Stated Preferences for Real Estate
Authors: Patunru Arianto A. , Braden John B. , Chattopadhyay Sudip
Published: February 2007

This article uses latent segmentation analysis to estimate the benefits of contaminant cleanup in Waukegan Harbor, Illinois. Survey responses to attitudinal and perception questions provide significant information about the existence of distinct preference groups. By comparison, the predictive usefulness of demographic covariates is unclear. The expected aggregate willingness‐to‐pay of Waukegan homeowners for full cleanup is approximately equivalent to a 20% increase in the market value of homes. The aggregate estimate is little affected by the identification of preference clusters.
Tenants, Landlords, and Soil Conservation
Authors: Lichtenberg Erik
Published: February 2007

It has long been argued that tenants tend to overexploit land, but this conventional wisdom has been derived largely without consideration of landlords' actions. We examine what happens when landlords can invest in durable conservation measures in addition to choosing rental contract terms. When tenants are risk neutral, landlords overinvest in conservation under cash rental contracts but can achieve first best levels of output and protection against land degradation when conservation investment is combined with share rental. When tenants are risk averse, the first best is unattainable. In this case, conservation investment combined with share rental results in output levels below the first best, while equilibrium conservation investment may be greater or less than the first best. These results suggest that contract form and conservation investments are likely made simultaneously, so that econometric studies of conservation practice adoption that treat rental status as exogenous are likely subject to bias.
Peanut Research and Poverty Reduction: Impacts of Variety Improvement to Control Peanut Viruses in Uganda
Authors: Moyo Sibusiso , Norton George W. , Alwang Jeffrey , Rhinehart Ingrid , Deom C. Michael
Published: February 2007

A procedure is developed and applied for predicting ex ante impacts of agricultural research on aggregate poverty, using as an example the poverty‐reducing impact of peanut research in Uganda. Market‐level information on economic surplus changes is combined with a procedure for allocating income changes to individual households. Characteristics of farmers that affect their likelihood of technology adoption are used to create a technology adoption profile. Associated changes in poverty resulting from adoption are computed using poverty indices. Predicted income changes at the household level are aggregated to the market level and reconciled with calculations of economic surplus changes.
Is There Persistence in the Impact of Emergency Food Aid? Evidence on Consumption, Food Security, and Assets in Rural Ethiopia
Authors: Gilligan Daniel O. , Hoddinott John
Published: February 2007

We identify the impact of emergency food aid programs after the 2002 drought in rural Ethiopia on future welfare. Based on a difference‐in‐differences matching estimator, participation in food‐for‐work increases growth in total consumption and food consumption eighteen months after the drought. Separately, receiving free food raises growth in food consumption, but, surprisingly, negatively impacts food security. Food‐for‐work benefited households in the middle and upper tail of the consumption distribution, while the better‐targeted free food program benefited the poorest. Evidence suggests these impacts demonstrate accumulated and persistent effects of food aid received in the first twelve months after the drought.
Migration, Fixed Costs, and Location‐Specific Amenities: A Hazard Analysis for a Panel of Males
Authors: Huffman Wallace E. , Feridhanusetyawan Tubagus
Published: February 2007

This article presents econometric estimates of the adult working‐age male hazard function of interstate migration fitted to data obtained from migration decisions of adult males over a twenty‐year period. The results show a strong negative effect of the real wage difference between origin and destination, and of fixed costs associated with a move, on the hazard rate of interstate migration. Farmers and other self‐employed males, and males who have school‐age children, have unusually low hazard rates of interstate migration. Although a high crime rate is shown to increase the real wage, it also has a separate positive effect on the hazard of migration.
Brand‐Supermarket Demand for Breakfast Cereals and Retail Competition
Authors: Chidmi Benaissa , Lopez Rigoberto A.
Published: February 2007

The Berry, Levinsohn, and Pakes (1995) market equilibrium model is extended to the supermarket chain level to examine consumer choices and retail competition for thirty‐seven brands of breakfast cereals in Boston. Estimated taste parameters for product characteristics vary significantly across consumers. Although consumers are price‐sensitive with respect to their chosen cereals, they exhibit strong brand and supermarket loyalty. Retail markups increase and marginal costs decrease with grocery market shares, attesting to oligopoly power with efficiencies. Markups decrease with the own‐price elasticity of demand, with Corn Flakes having the highest markups. A detailed picture of consumer response and supermarket competition is provided.
Wildlife Damage and Agriculture: A Dynamic Analysis of Compensation Schemes
Authors: Rondeau Daniel , Bulte Erwin
Published: February 2007

We study the environmental and economic consequences of introducing a program to compensate peasants for damages caused by wildlife. We show that the widely held belief that compensation induces wildlife conservation may be erroneous. In a partially open economy, compensation can lower the wildlife stock and result in a net welfare loss for local people. In an open economy, compensation can trigger wildlife extinction and also reduce welfare. We identify the conditions leading to a reduction of the wildlife stock and discuss the implications for current and planned compensation programs in Africa and Asia.
Contract Enforcement, Social Efficiency, and Distribution: Some Experimental Evidence
Authors: Wu Steven Y. , Roe Brian
Published: February 2007

We use economic experiments to investigate how different contract enforcement regimes affect efficiency and the distribution of surplus in a vertically coordinated market with buyer concentration. We find that if a third party (e.g., government) perfectly enforces contracts, social efficiency is enhanced. We also find that when third‐party enforcement is imperfect, social efficiency will not necessarily decrease because trading partners find ways to self enforce contracts. However, opportunistic behavior by some traders leaves some sellers (growers) with ex post profits below reservation levels. Finally, partial or one‐sided third‐party enforcement causes significant efficiency losses by constraining subjects' ability to use informal enforcement instruments.
Environmental Emissions and Production Economics: Implications of the Materials Balance
Authors: Ebert Udo , Welsch Heinz
Published: February 2007

In modeling emissions, the literature has usually specified an explicit emission function, or treated emissions as a production input. We examine the validity of these approaches, taking into account the materials balance principle. We show that a technology can equivalently be described by (i) a production function with material and nonmaterial inputs and bounded marginal product of the material input, (ii) a well‐behaved production function with emissions as an input, and (iii) a well‐behaved emission function, if the materials balance is accounted for as an additional condition. We offer a forma derivation of common, but not rigorously established modeling approaches.
Changes in the dermoscopic appearance of melanocytic naevi after photochemotherapy or narrow‐band ultraviolet B phototherapy
Authors: Kilinc Karaarslan I , Teban L , Dawid M , Tanew A , Kittler H
Published: February 2007

Background  Although phototherapeutic modalities are commonly used for the treatment of skin diseases, the effects of therapeutic ultraviolet (UV) irradiation on the dermoscopic appearance of melanocytic naevi are unknown.

Objectives  We aimed to analyse the effects of photochemotherapy (psoralen plus ultraviolet A, PUVA) and narrow‐band ultraviolet B phototherapy (NB‐UVB) on the dermoscopic appearance of naevi.

Patients and methods  We monitored 187 melanocytic naevi of 38 patients receiving NB‐UVB or PUVA treatment for miscellaneous skin diseases. Dermoscopic images of naevi were taken before, shortly after, and after a median of 31 weeks after the UV therapy. A random selection of naevi was covered during UV treatment, the others remained uncovered. Baseline and follow‐up images of naevi were viewed side by side on a computer screen to compare size, pigmentation, and dermoscopic structure of naevi.

Results  Twenty‐one patients received NB‐UVB treatment, and 17 patients received PUVA treatment. Of 187 naevi, 70 (37%) were covered and 117 (63%) were uncovered during UV treatment. When NB‐UVB‐ and PUVA‐treated patients were analysed together, an increase in size of uncovered lesions was seen in both treatment groups. Pigmentation appeared darker at the end of UV treatment in 67.5% (n = 79) of uncovered naevi compared with 41.4% (n = 29) of covered naevi (P < 0.001). In patients receiving NB‐UVB therapy, a significant increase in the number of dots or globules in 20.3% (n = 14) of uncovered naevi compared with only 5.0% (n = 2) of covered naevi (P = 0.03) was found. This effect was not observed after PUVA therapy. With the exception of four naevi with continuous enlargement and seven naevi with a persisting increase in dots and globules, the observed changes were reversible. All naevi with persistent changes belonged to the NB‐UVB group.

Conclusion  In general, PUVA and NB‐UVB therapy cause reversible dermoscopic changes in melanocytic naevi. Increase in dots and globules is more frequent with NB‐UVB.
Comparison of systemic PUVA and NB‐UVB in the treatment of vitiligo: an open prospective study
Authors: Bhatnagar A , Kanwar AJ , Parsad D , De D
Published: February 2007

Background  Vitiligo is a common pigmentary disorder with great cosmetic and psychological morbidity. No treatment available is a definitive cure. Systemic psoralen and ultraviolet A (PUVA) has been the mainstay of treatment. Narrow‐band ultraviolet B (NB‐UVB) has been recently introduced. Although retrospective comparative study of systemic PUVA and NB‐UVB has been published from our centre, no prospective study has been reported to date.

Aims  To investigate the position of NB‐UVB vis‐à‐vis PUVA in terms of efficacy, time to repigment and adverse effects and to help decide if one therapy has an advantage over another in the treatment of vitiligo.

Subjects and methods  It was a randomized, open, prospective study of 50 patients divided equally in TMP PUVA and NB‐UVB groups. The study period was from January 2004 to June 2005.

Results  The mean degree of repigmentation attained in the NB‐UVB group was 52.24% over a mean treatment period of 6.3 months, whereas in the PUVA group it was 44.7% in a mean period of 5.6 months (P = 0.144). After excluding the results of therapy‐resistant sites, that is, hands and feet, the mean degree of repigmentation in the NB‐UVB group was 67.57%, whereas in the PUVA group it was 54.2% (P = 0.007).

Conclusions  NB‐UVB performed better in comparison to TMP PUVA in terms of mean total repigmentation when traditionally considered therapy‐resistant sites were excluded.
Familial reactive perforating collagenosis: a clinical, histopathological study of 10 cases
Authors: Ramesh V , Sood N , Kubba A , Singh B , Makkar R
Published: February 2007

Objective   To study the clinical and histopathological features of familial reactive perforating collagenosis (RPC).

Material and methods  Ten patients, including affected siblings in three, took part in the study. Parental consanguinity was present in one. Histopathological study was performed in all patients.

Results  The eruptions appeared mainly during infancy or early childhood as papules showing a central plug, which subsided within 10 weeks. Areas commonly affected were the face, extremities and trunk. Rare sites were the scalp, ears and buttocks. One pregnant woman, in whom RPC had first manifested around puberty, had relatively widespread lesions. In those with seasonal variation, recurrences were seen a little more frequently in summer than in winter owing to the longer duration of the former. Histopathology confirmed the diagnosis with follicular involvement in four cases. In two patients whose backs were also affected, the lesions went unnoticed, as they were small and inconspicuous. In addition, the brother of a girl with RPC who claimed to be free of the dermatosis, had facial scars suggestive of RPC in the past.

Conclusions  Familial RPC can remain quiescent for a long period and the inherited defect not only shows extreme variability in expression but also demonstrates that lesions can be few and localized so as to escape notice in individuals and family members presenting with this benign, uncommon and self‐subsiding dermatosis. In all patients topical retinoic acid was helpful in early regression. Sunscreens may mitigate the severity of RPC in those whose lesions are precipitated in summer but this needs further evaluation.
Three Common Intronic Variants in the Maternal and Fetal Thiamine Pyrophosphokinase Gene (TPK1) are Associated with Birth Weight
Authors: Fradin D. , Bougneres P.
Published: February 2007

Extreme variations in birth weight increase immediate postnatal mortality and morbidity, and are also associated with the predisposition to metabolic diseases in late adulthood. Birth weight in humans is influenced by yet unknown genetic factors. Since the 7q34‐q35 region showed linkage with birth weight in a recent human genome scan (p = 8.10−5), this study investigated the TPK1 (thiamine pyrophosphokinase) gene locus, located in 7q34‐36. Having found no coding variants in the TPK1 gene, we genotyped 43 non coding SNPs spanning a region of 420kb, and used the QTDT method to test their association with birth weight in 964 individuals from 220 families of European ancestry. Family‐based tests detected association of 8 SNPs with birth weight (p<0.008), but after correction for multiple tests only rs228581 C/T (p = 0.03), rs228582 A/G (p = 0.04) and rs228584 C/T (p = 0.03) were still associated with birth weight, as well as their T‐A‐T haplotype (p = 0.03). In addition, we found an association between maternal rs228584 genotype and offspring birth weight (p = 0.027).

These observations suggest that genomic variations in the fetal and maternal TPK1 gene could contribute to the variability of birth weight in normal humans.
Absence of mechanical loading in utero influences bone mass and architecture but not innervation in Myod‐Myf5‐deficient mice
Authors: Gomez Cédric , David Valentin , Peet Nicola M. , Vico Laurence , Chenu Chantal , Malaval Luc , Skerry Timothy M.
Published: February 2007

Although the responses of bone to increased loading or exercise have been studied in detail, our understanding of the effects of decreased usage of the skeleton has been limited by the scarcity of suitable models. Such models should ideally not affect bone innervation, which appears to be a mediator of physiological responses of bone to unloading. MyoD–/–/Myf5–/– (dd/ff) mice lack skeletal muscle, so the fetuses develop without any active movement in utero and die soon after birth. We used micro‐compter tomography and histology to analyse their bone development and structure during endochondral ossification in parallel with the establishment of bone innervation. Long bones from mutant mice were found to be profoundly different from controls, with shorter mineralized zones and less mineralization. They lacked many characteristics of adult bones – curvatures, changes in shaft diameter and traction epiphyses where muscles originate or insert – that were evident in the controls. Histologically, dd/ff mice showed the same degree of endochondral development as wild‐type animals, but presented many more osteoclasts in the newly layed bone. Innervation and the expression pattern of semaphorin‐3A signalling molecules were not disturbed in the mutants. Overall, we have found no evidence for a major defect of development in dd/ff mice, and specifically no alteration or delay in endochondral ossification and bone innervation. The altered morphological features of dd/ff mice and the increased bone resorption show the role of muscle activity in bone shaping and the consequences of bone unloading.
CAPITAL STRUCTURE, SHAREHOLDER RIGHTS, AND CORPORATE GOVERNANCE
Authors: Jiraporn Pornsit , Gleason Kimberly C.
Published: February 2007

We show how capital structure is influenced by the strength of shareholder rights. Our empirical evidence shows an inverse relation between leverage and shareholder rights, suggesting that firms adopt higher debt ratios where shareholder rights are more restricted. This is consistent with agency theory, which predicts that leverage helps alleviate agency problems. This negative relation, however, is not found in regulated firms (i.e., utilities). We contend that this is because regulation already helps alleviate agency conflicts and, hence, mitigates the role of leverage in controlling agency costs.
RULE CHANGES AND UNCERTAINTY IN DISCRIMINATORY AND UNIFORM PRICE AUCTIONS
Authors: Beierlein Jaclyn , Kato Hideaki Kiyoshi
Published: February 2007

The auction literature indicates that uncertainty about the value of auctioned goods increases underpricing in discriminatory price auctions. Such uncertainty has a smaller effect on uniform price auctions because the pricing rule aggregates bidders' information. We find that uncertainty resulting from inexperience with an auction mechanism has similar effects. Using initial public offering (IPO) data from Japan and Israel, we find that average underpricing increases temporarily in Japan's discriminatory price auctions after changes in the auction rules, which suggests that bidders reduce their bids in response to uncertainty. Underpricing in Israel's uniform price auctions is not affected by rule changes.
THE IMPORTANCE OF LIQUIDITY AS A FACTOR IN ASSET PRICING
Authors: Keene Marvin A. , Peterson David R.
Published: February 2007

We employ the Fama‐French time‐series regression approach to examine liquidity as a risk factor affecting stock returns. Prior studies establish liquidity as an important consideration in investment decisions. Here, liquidity is found to be an important factor affecting portfolio returns, even after the effects of market, size, book‐to‐market equity, and momentum are considered. Nonzero intercepts remain, however, indicating continued missing risk factors.
APPLICABILITY OF THE FAMA‐FRENCH THREE‐FACTOR MODEL IN FORECASTING PORTFOLIO RETURNS
Authors: Hu Ou
Published: February 2007

For the model‐based estimation of the equity cost of capital, evidence shows that the common practice of using the average historical factor premiums as the estimates of the next‐period factor premiums generates inaccurate estimates. I propose an alternative way to estimate factor premiums by using the structural variables that are important predictors of future asset returns. Based on the out‐of‐sample results from a trading strategy with four in‐sample model‐selection criteria, I find that my estimation procedure performs better than the common practice even when transaction costs are considered.
FOREIGN INVESTOR PARTICIPATION IN PRIVATIZATIONS: DOES THE INSTITUTIONAL ENVIRONMENT MATTER?
Authors: Boubakri Narjess , Cosset Jean‐Claude , Guedhami Omrane , Omran Mohammed
Published: February 2007

We examine the determinants of foreign investors' participation in the privatization process of developing countries. First, we estimate the probability that foreign investors target privatized firms in a given country. We show that a favorable legal environment where investor protection is higher enhances foreign investors' participation. Foreigners also prefer large, strategic firms from high‐growth economies and socially stable countries with low political risk. Second, we restrict our analysis to privatized firms that foreign investors actually choose and show that the stakes foreigners hold are larger if the firms are privatized by private sales as opposed to public offerings.
EFFECT OF FED POLICY ACTIONS ON THE DEFAULT LIKELIHOOD OF COMMERCIAL BANKS
Authors: Akhigbe Aigbe , Madura Jeff , Martin Anna D.
Published: February 2007

Using a measure of default likelihood based on an option pricing method, we provide evidence that Fed policy actions affect the financial distress of commercial banks. When the Fed increases (decreases) interest rates, the measure of default likelihood increases (decreases). We show that when the Fed uses a tight money policy, the increase in default likelihood is more pronounced for banks that have less capital, have greater financial leverage, are smaller, have fewer growth opportunities, and have lower asset quality. Additionally, the effects on bank default likelihood are more pronounced when the Fed's policy signals less concern about economic growth, as indicated by its bias toward further tightening, and when there is a market expectation of higher short‐term market rates in the future.
Cancer, cyclo‐oxygenase and nonsteroidal anti‐inflammatory drugs – can we combine all three?
Authors: Hayes A.
Published: February 2007

Understanding the molecular biology of cancer and identification of the aberrant mechanisms that permit unrestricted cell growth is fundamental to the development of cancer treatment and prevention strategies. When defective molecular pathways have been uncovered, targeted therapies aimed at specific disruption to the biology of the cell can be developed. Such targeted treatments might more effectively kill cancer and spare normal tissues. The significance of the cyclo‐oxygenase (COX) enzymatic pathways has emerged over the last 20 years and is currently a focus of study in some cancers of humans and veterinary species. This pathway is relatively easy to inhibit using nonsteroidal anti‐inflammatory drugs that are commonly in use in veterinary practice, making this pathway appear as a logical target. However, COX is just one of many aberrant cell signalling pathways identified in carcinogenesis. This review explores possible benefits and current limitations of treating cancer with COX‐inhibiting drugs in veterinary practice.
Five decades of progress in haematopoietic cell transplantation based on the preclinical canine model
Authors: Lupu M. , Storb R.
Published: February 2007

The preclinical canine model has proved valuable for the development of principles and techniques of haematopoietic cell transplantation (HCT) applicable to human patients. Studies in random‐bred dogs concerning the impact of histocompatibility barriers on engraftment and graft‐versus‐host disease, the kinetics of immunological reconstitution, the efficacy of various pretransplant conditioning regimens, post‐transplantation immunosuppression protocols, treatment of malignant diseases, and graft‐versus‐tumour effects have advanced HCT from an investigational therapy with uncertain clinical benefit half a century ago to an important treatment choice for thousands of patients treated annually in transplantation centres worldwide. More recent preclinical canine studies have resulted in the clinical translation of non‐myeloablative, minimally invasive transplantation protocols that have extended allogeneic HCT to include older human patients with malignant and non‐malignant, acquired or inherited haematological disorders, and those with comorbid conditions. Here, we review the contributions of the canine model to modern HCT and describe the usefulness of HCT for the treatment of canine haematological disorders.
3‐Phosphoinositide‐dependent protein kinase‐1/Akt signalling and inhibition in a canine prostate carcinoma cell line
Authors: Alvarez F. J. , Murahari S. , Couto C. G. , Rosol T. J. , Kulp S. K. , Chen C.‐S. , Kisseberth W. C.
Published: February 2007

Deregulation of the 3‐phosphoinositide‐dependent protein kinase‐1 (PDK‐1)/Akt signalling pathway is associated with prostate cancer development and progression. Inhibition of PDK‐1/Akt signalling can be achieved using structurally optimized celecoxib derivatives such as OSU‐03012. In this study, we treated the novel canine prostate cancer cell line, Ace‐1, with OSU‐03012 or dimethyl sulphoxidein vitro. We found that Akt was constitutively phosphorylated in the canine prostate cancer cell line Ace‐1 and that there was a dose‐dependent decrease in cell viability, and Akt and glycogen synthase kinase‐3β phosphorylation, in response to OSU‐03012 treatment. This was accompanied by a dose‐dependent increase in apoptosis. These data suggest that Akt signalling pathway inhibition is a potential strategy for the treatment of dogs with prostate cancer and that canine prostate cancer is a relevant large animal model for evaluating Akt pathway inhibitors such as OSU‐03012 for use in people.
Efficacy of injectable maropitant (Cerenia™) in a randomized clinical trial for prevention and treatment of cisplatin‐induced emesis in dogs presented as veterinary patients
Authors: Vail D. M. , Rodabaugh H. S. , Conder G. A. , Boucher J. F. , Mathur S.
Published: February 2007

Chemotherapy‐induced nausea and vomiting (CINV) is a common side‐effect of cisplatin therapy. Maropitant (Cerenia™), a novel neurokinin‐1 receptor antagonist, was evaluated for prevention and treatment of cisplatin‐induced emesis in tumour‐bearing dogs. Dogs (n= 122) were randomly allocated to three treatment groups: T01, placebo before and after cisplatin; T02, placebo before and maropitant after cisplatin; or T03, maropitant before and placebo after cisplatin. Maropitant treatment (T02) following a cisplatin‐induced‐emetic event resulted in significantly fewer subsequent emetic events (P= 0.0005) than in placebo‐treated dogs (T01). In placebo‐treated (T01) dogs, 56.4% were withdrawn from the study because of treatment failure compared with 5.3% in group T02. When maropitant was administered prior to cisplatin treatment (T03) in a prevention regime, 94.9% did not vomit compared with only 4.9% of placebo‐treated dogs, and significantly fewer emetic events (P< 0.0001) were observed in those dogs that did vomit. In summary, maropitant was safe and highly effective in reducing or completely preventing cisplatin‐induced emesis.
Nation, State and the Modern Transformation of Korean Social Structure in the Early Twentieth Century
Authors: Hwang Kyung Moon
Published: February 2007

When assessing social change in modern Korea, the tremendous material transformation of the second half of the twentieth century has tended to obscure the advances of the late nineteenth and early twentieth centuries. This article examines the distinctive means by which both nation building and state making contributed to the formation of Korea's modern social structure well before the full advent of industrialisation and urbanisation. It argues that the processes of national identity formation, particularly in the absence of an autonomous state during the period of Japanese colonial rule (1910–45), drew from multiple stimuli, including religion, class and a recognition of the urgency of social levelling. The state, meanwhile, followed different developmental paths in its institutional and ideological manifestations, but in both instances, the contributions of Koreans themselves to the process, even during the colonial period, placed a lasting imprint on the state's relationship to modern social change. The legacy of this connection continues to shape how Koreans perceive both their present and their past.
Effects of Cyclic Hydrostatic Pressure on the Metabolism of Human Osteoarthritic Chondrocytes Cultivated in a Collagen Gel
Authors: Gavénis Karsten , Kremer André , Von Walter Matthias , Hollander Dirk A. , Schneider Ulrich , Schmidt‐Rohlfing Bernhard
Published: February 2007

Abstract:  Among other parameters, the application of mechanical force may provide an important stimulus in modulating the structure and function of tissue‐engineered articular cartilage. We developed a cultivation chamber in which six collagen type‐I gel samples, seeded with human osteoarthritic chondrocytes, can be cultivated simultaneously. A cyclic hydrostatic pressure of up to 40 kPa with a frequency of 0.0125 Hz was applied, and cultivation was performed for 1, 4, 7, or 14 days. Histological examinations revealed a spheroidal cell morphology in the treatment group. In contrast, control samples of the same patients represented a more fibroblastic appearance. Collagen type‐II (col‐II) protein was found in the very pericellular region of all investigated samples; the col‐II content did not obviously vary between the control and treatment groups. In the treatment group, col‐II and aggrecan gene expression were elevated. A spectrophotometric quantification of proteoglycan concentrations in media supernatants revealed a statistically significant enhancement in the treatment group.
Implantation of Decellularized Small‐caliber Vascular Xenografts With and Without Surface Heparin Treatment
Authors: Wang Xue‐Ning , Chen Chang‐Zhi , Yang Min , Gu Y. John
Published: February 2007

Abstract:  Heparin treatment of decellularized xenografts has been reported to reduce graft thrombogenicity. However, little is known about the in vivo comparison of heparin‐treated with non‐heparin‐treated xenografts, especially for small‐caliber vascular implants. We implanted either a heparin‐treated or a non‐heparin‐treated canine carotid artery as bilateral carotid xenograft in rabbits (n = 24). Small‐caliber xenografts (3∼4 mm) were decellularized by enzymatic and detergent extraction and were further covalently linked with heparin. During implantation, thrombosis rate was 4% in the heparin‐treated xenografts and 25% in the non‐heparin‐treated xenografts after 3 weeks (P < 0.05). After 6 months, it was 8 versus 58%, respectively (P < 0.01). Both heparin‐treated and non‐heparin‐treated xenografts harvested at the end of 3 and 6 months showed a satisfactory cellular reconstruction of either smooth muscle cells or endothelial cells. These results indicate that heparin treatment of the small‐caliber decellularized xenograft reduces the in vivo thrombogenicity. Both heparin‐treated and non‐heparin‐treated xenografts seem to undergo a similar cellular remodeling process up to 6 months.
Time‐related Histopathologic Analyses of Immunologically Untreated Porcine Valved Conduits Implanted in a Porcine‐to‐Goat Model
Authors: Kim Won Gon , Sung Kiick , Seo Jeong Wook
Published: February 2007

Abstract:  This study was performed to evaluate the clinical feasibility of use of immunologically nontreated xenogenic valves, using a porcine‐to‐goat pulmonary valved conduit implantation model. Porcine pulmonary valve conduits were prepared with no specific immunological treatment and implanted in the right ventricular outflow tract of goats under cardiopulmonary bypass. The goats were assigned at predetermined intervals (1 day, 1 week, and 3, 6, and 12 months) as two animals for each interval. Echocardiographic examinations of the valves were performed before sacrifice. Upon retrieving the xenograft specimens, they were inspected visually and microscopically. Ten of the 12 animals survived the predetermined observation periods. Variable degrees of pulmonary regurgitation were the main findings on echocardiographic evaluations. On gross examination of the explanted specimens, all leaflets, except in one animal that prematurely died, were fairly well preserved. They were slightly shortened but free of thrombosis or vegetation. Aneurysmal dilatations of the anterior wall of the implanted pulmonary artery were observed in one of 12‐month‐survival animals and in another one of 3‐month‐survival animals. Microscopically, the three components of implanted xenografts (the pulmonary artery, valve, and infundibulum) were shown to be gradually replaced with host cells in time, while maintaining structural integrity. The nuclei of the donor tissue disappeared through pyknosis and karyolysis. In conclusion, immnunologically untreated xenogenic pulmonary valved conduits can be an alternative potential as valve substitutes with distinctive advantages of providing self‐healing potential, despite a few problems observed in the current study such as occurrences of pulmonary regurgitation and sporadic cases of aortic aneurysm.
Hemodynamic Controller for Left Ventricular Assist Device Based on Pulsatility Ratio
Authors: Choi Seongjin , Boston J. Robert , Antaki James F.
Published: February 2007

Abstract: Hemodynamic control of left ventricular assist devices (LVADs) is generally a complicated problem due to diverse operating environments and the variability of the patients: both the changes in the circulatory and metabolic parameters as well as disturbances that require adjustment to the operating point. This challenge is especially acute with control of turbodynamic blood pumps. This article presents a pulsatility ratio controller for LVAD that provides a proper perfusion according to the physiological demands of the patient, while avoiding adverse conditions. It utilizes the pulsatility ratio of the flow through the pump and pressure difference across the pump as a control index and adjusts the pump speed according to the reference pulsatility ratio under the different operating conditions. The simulation studies were performed to evaluate the controller in consideration of the sensitivity to afterload and preload, influence of the contractility, and effect of suction sensitivity. The controller successfully adjusts the pump speed according to the reference pulsatility ratio, and supports the natural heart under diverse pump operating conditions. The resulting safe pump operations demonstrate the solid performance of the controller in terms of sensitivity to afterload and preload, influence of the contractility, and effect of suction sensitivity.
Leukocyte–Platelet Aggregates and Monocyte Tissue Factor Expression in Bovines Implanted With Ventricular Assist Devices
Authors: Snyder Trevor A. , Litwak Kenneth N. , Tsukui Hiroyuki , Akimoto Takehide , Kihara Shin'Ichiro , Yamazaki Kenji , Wagner William R.
Published: February 2007

Abstract:  Infection and thromboembolism remain significant complications associated with ventricular assist device (VAD) support, including the newer rotary VADs, limiting wider adoption of this promising technology. These complications persist in spite of extensive preclinical testing in large animal models. The amount of biocompatibility information collected during preclinical trials is limited due to a lack of available assays. We thus developed three flow cytometric assays to measure leukocyte–platelet aggregates and monocyte tissue factor expression and applied them to 26 bovines implanted with two types of rotary VADs. All animals displayed low levels of circulating aggregates and monocytes expressing tissue factor prior to device implant. The assay values significantly increased following VAD implant, then usually declined to a lower, yet significantly elevated versus baseline, level indicative of ongoing inflammation. The implementation of more robust biocompatibility assays for the evaluation of cardiovascular device performance and modification might ultimately contribute to the development of safer artificial organs.
Air Bubbles Pass the Security System of the Dialysis Device Without Alarming
Authors: Jonsson Per , Karlsson Lars , Forsberg Ulf , Gref Margareta , Stegmayr Christofer , Stegmayr Bernd
Published: February 2007

Abstract:  During hemodialysis microembolic findings have been noted after the venous chamber (subclavian vein). The aim of this study was to evaluate if air could pass the venous chamber and, if so, if it passes the safety‐system detector for air‐infusion without triggering an alarm.Various in vitro dialysis settings were performed using regular dialysis devices. A dextran fluid was used instead of blood to avoid the risk of development of emboli. Optical visualization as well as recirculation and collection of eventual air into an intermediate bag were investigated. In addition, a specifically designed ultrasound monitor was placed after the venous air trap to measure the presence of eventual microbubbles. Speed of dialysis fluid was changed, as was the level of the fluid in the air trap. Thereby a fluid level was considered “high” if it was close to the top of the air trap and “low” if it was around the mid part of the air trap. By optical vision microbubbles were seen at the bottom of the air trap and could pass the air trap towards the venous line without alarming. During recirculation several mL of air were collected in an intermediate bag after the venous line. Ultrasound monitoring exhibited the presence of microbubbles of the size of approximately 5 µm upwards passing to the venous line in all runs performed. Amount of bubbles differed between devices and in general an increased fluid speed correlated significantly with the increased counts of microbubbles/min. No alarming of the detector occurred. A more concentrated fluid allowed higher counts/min when flow was increased to 600 mL/min. Data revealed that air passes the safety‐sensor in the air trap without alarming. The presence of air increased in general with fluid speed and a lower fluid level in the air trap. Differences were present between devices. If this affects the patients has to be elucidated.
Extracorporeal Bioartificial Liver Using the Radial‐flow Bioreactor in Treatment of Fatal Experimental Hepatic Encephalopathy
Authors: Kanai Hideki , Marushima Hideki , Kimura Naofumi , Iwaki Takamasa , Saito Masaya , Maehashi Haruka , Shimizu Keiko , Muto Makiko , Masaki Takahiro , Ohkawa Kiyoshi , Yokoyama Keitaro , Nakayama Masaaki , Harada Tohru , Hano Hiroshi , Hataba Yoshiaki , Fukuda Takahiro , Nakamura Masahiko , Totsuka Naoto , Ishikawa Shutaro , Unemura Yasuki , Ishii Yuji , Yanaga Katsuhiko , Matsuura Tomokazu
Published: February 2007

Abstract:  An extracorporeal bioartificial liver (BAL) that could prevent death from hepatic encephalopathy in acute hepatic insufficiency was aimed to develop. A functional human hepatocellular carcinoma cell line (FLC‐4) was cultured in a radial‐flow bioreactor. The function of the BAL was tested in mini‐pigs with acute hepatic failure induced by α‐amanitin and lipopolysaccharide. When the BAL system was connected with cultured FLC‐4 to three pigs with hepatic dysfunction, all demonstrated electroencephalographic improvement and survived. Relatively low plasma concentrations of S‐100 β protein, as a marker of astrocytic damage, from pigs with hepatic failure during BAL therapy were noted. BAL therapy can prevent irreversible brain damage from hepatic encephalopathy in experimental acute hepatic failure.
An In Vitro and In Vivo Study of the Detection and Reversal of Venous Collapse During Extracorporeal Life Support
Authors: Simons Antoine P. , Reesink Koen D. , Molegraaf Georgette V. , Van Der Nagel Theo , De Jong Monique M. , Severdija Ervin E. , De Jong Dick S. , Van Der Veen Frederik H. , Maessen Jos G.
Published: February 2007

Abstract: The objective of this study was to investigate venous collapse (VC) related to venous drainage during the use of an extracorporeal life support circuit. A mock circulation was built containing a centrifugal pump and a collapsible vena cava model to simulate VC under controlled conditions. Animal experiments were performed for in vivo verification. Changing pump speed had a different impact on flow during a collapsed and a distended caval vein in both models. Flow measurement in combination with pump speed interventions allows for the detection and quantitative assessment of the degree of VC. Additionally, it was verified that a quick reversal of a VC situation could be achieved by a two‐step pump speed intervention, which also proved to be more effective than a straightforward decrease in pump speed.
The Sensor in the Venous Chamber Does Not Prevent Passage of Air Bubbles During Hemodialysis
Authors: Stegmayr Bernd , Forsberg Ulf , Jonsson Per , Stegmayr Christofer
Published: February 2007

Abstract:  We previously showed, in vitro, that micro bubbles pass the air trap without inducing an alarm. The aim was to investigate if micro bubbles bypass the detector during hemodialysis (HD). During HD (40 patients, 47 HD sessions, 231 measurements), an ultrasound detector was fixed just after the venous air trap. Micro bubble size was measured in the range from 5 µm up to >42.5 µm. Blood flow was at a mean 346 mL/min (SD ± 57). The mean of all micro bubbles per minute, without inducing an alarm, was at start 128 (range 0–769). Measurements revealed the presence of micro bubbles in all of the series and in 90% of the measurements. There was no difference between start and end of the same dialyses. There was a correlation between blood flow and extent of micro bubbles for the smaller sizes and the sum of all bubbles (r ≥ 0.29, P ≤  0.026). Micro bubbles passed the air trap without alarming. Most bubbles were approximately 5 µm.
Modular Hip Stems: Determination of Disassembly Force of a Neck–Stem Coupling
Authors: Pallini Francesco , Cristofolini Luca , Traina Francesco , Toni Aldo
Published: February 2007

Abstract:  An increasing number of hip prostheses feature double head–neck and neck–stem modularities. One possible complication is loosening of the neck–stem coupling. Current surgical technique includes application of hammer blows to the proximal end of the neck–stem coupling. This could compromise the cleanness of the head–neck modularity and damage the bearing surfaces. The goal of this work was to assess whether such hammer blows are really necessary to avoid neck–stem disassembly during in vivo service. Commercially available hip stems featuring neck–stem modularity were tested. Extraction force was measured in vitro when different levels of press fitting were simulated (manual assembly followed by various combinations of simulated loads) to assess critical conditions in relation to surgical technique and applied loads. The disassembly force after manual insertion followed by the first small postoperative loads imposed by the patient during walking was as high as that obtained with hammer blows. Thus, application of hammer blows to fix the neck–stem coupling seemed unnecessary.
Tissue Doppler Imaging in the Evaluation of the Left and Right Ventricular Diastolic Functions in Rheumatoid Arthritis
Authors: Birdane Alparslan , Korkmaz Cengiz , Ata Necmi , Cavusoglu Yuksel , Kasifoglu Timucin , Dogan Sait Mesut , Gorenek Bulent , Goktekin Omer , Unalir Ahmet , Timuralp Bilgin
Published: February 2007

Objective: Previous studies have reported that cardiovascular involvement in rheumatoid arthritis (RA) occurs frequently. Although ventricular functions of RA have been investigated through the standard Doppler in RA, they have yet to be investigated thoroughly by means of the relatively new and advantageous tissue Doppler imaging (TDI). The present study aims to investigate left and right ventricular functions in RA patients by means of TDI and standard Doppler echocardiography. Methods: A total of 60 patients with longstanding RA and 40 control subjects were included in the study and their left and right ventricular functions were assessed by standard pulsed‐wave Doppler echocardiography, the color M‐mode flow propagation velocity, and TDI. The left ventricular TDI was achieved at four different sites (lateral, septal, anterior, and inferior walls), while the right ventricular TDI was achieved through the tricuspid lateral annulus. Results: When compared with controls, the RA group showed that basal clinic and echocardiographic parameters, early (E) and late (A) diastolic velocities of atrioventricular valves, E/A ratio, and pulmonary venous Doppler parameters of these two groups were similar. It was determined that left and right ventricular E‐wave deceleration times and isovolumic relaxation times of the RA patients were determined to have increased in comparison with those of the subjects in the healthy Control Group (P < 0.05). RA patients had significantly lower color M‐mode flow propagation velocity (P < 0.05). While S′ peak and E′ peak, two of the left and right ventricular TDI parameters, were similar in both groups, A′ peak, E′/A′, and E/E′ parameters in RA showed statistically significant differences in RA patients. Conclusion: A comparison between age and sex of RA patients and healthy individuals revealed that left and right ventricular TDI parameters of RA patients were impaired, which led us to conclude that both of the ventricles could have been involved.
Phosphatidylinositol Synthase of Tetrahymena: Inositol Isomers as Substrates in Phosphatidylinositol Biosynthesis and Headgroup Exchange Reactions
Authors: RIGGS BRIDGET M. , LANSLEY TANYA A. , RYALS PHILLIP E.
Published: February 2007

ABSTRACT. Phosphatidylinositol (PtdIns) synthase in microsomal fractions derived from Tetrahymena vorax was studied to determine its activity requirements. The suitability of inositol isomers as substrates for the synthase and in headgroup exchange reactions also was investigated. Tetrahymena PtdIn synthase activity was optimum in the presence of 2 mM MgCl2 plus 2 mM MnCl2, a pH of 7.8, and a temperature of 30°C. The enzyme retained approximately 80% of its activity after incubation at 70°C for 10 min. PtdIns headgroup exchange activity was maximal in the presence of cytidine monophosphate. By following either the accumulation of radiolabeled reaction products or the loss of radiolabel from precursors, each of the inositol isomers tested appeared to serve as substrates for both the PtdIns synthase and PtdIns:inositol phosphatidyl transferase activities. In each case, myo‐inositol and scyllo‐inositol were the preferred substrates. The data suggest two routes for the formation of phosphatidyl‐non‐myo‐inositols in Tetrahymena and the potential for the production of novel, non‐myo‐inositol‐containing second messengers.