bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heinz Tiedemann
Authors: Niehrs Christof 
Published: January 2004

AbstractHeinz Tiedemann ist der letzte noch lebende Repräsentant der deutschen Schule, die einst als „Entwicklungsmechanik”︁ bezeichnet wurde. Er widmete sein wissenschaftliches Leben der Untersuchung der Amphibienentwicklung und hat Pionierarbeit geleistet, um embryonale Induktoren zu charakterisieren. Seine Entdeckungen sind heute besonders aktuell, denn mit solchen Wachstumsfaktoren versucht man das Verhalten von Stammzellen zu beeinflussen, um Therapien für degenerative Krankheiten zu entwickeln. Seine „Erinnerungen an das XX. Jahrhundert”︁ enthalten spannende Einblicke in die Wissenschaftsgeschichte und die Anfänge der molekularen Entwicklungsbiologie.
Pramlintide reduces postprandial glucose excursions when added to insulin lispro in subjects with type 2 diabetes: a dose‐timing study
Authors: Maggs David G. , Fineman Mark , Kornstein Jonathan , Burrell Terrie , Schwartz Sherwyn , Wang Yan , Ruggles James A. , Kolterman Orville G. , Weyer Christian 
Published: January 2004

AbstractBackgroundTo assess the postprandial glucose‐lowering effect of the human amylin analog pramlintide when given with insulin lispro in subjects with type 2 diabetes, with an emphasis on the optimal dose timing relative to meals.MethodsIn this randomized, single‐blind, placebo‐controlled, five‐way crossover study, 19 subjects with type 2 diabetes using insulin lispro underwent five consecutive mixed‐meal tests. In randomized order, subjects received subcutaneous injections of placebo at −15 min or 120‐µg pramlintide at −15, 0, +15, or +30 min relative to the standardized breakfast after an overnight fast. Insulin lispro was injected at 0 min at doses that were adjusted appropriately for both the content of the standardized meal and the anticipated effects of pramlintide. Plasma glucose concentrations were measured before and during the 4‐h postmeal period.ResultsWhen injected at 0 min, pramlintide reduced the postprandial glucose excursion by 81% compared to insulin lispro + placebo (incremental AUC0–4 h (mean ± SE) 2.0 ± 1.5 vs. 10.4 ± 2.2 mmol/h/L, P < 0.05). When pramlintide was injected at −15, +15, and +30 min, the postprandial incremental glucose AUC0–4 h was also significantly reduced (P < 0.05), but to a lesser extent (42 to 73%). Pramlintide treatment was well tolerated and no serious adverse events were reported.ConclusionsAdministration of pramlintide either at or just prior to a meal caused a greater reduction in postprandial glucose than either administration of placebo or postmeal pramlintide injections in subjects with type 2 diabetes treated with a rapid‐acting insulin analog, insulin lispro. Copyright © 2004 John Wiley & Sons, Ltd.
Glutathione metabolism and oxidative stress in neonatal rat tissues from streptozotocin‐induced diabetic mothers
Authors: Raza Haider , John Annie 
Published: January 2004

AbstractBackgroundDiabetes in pregnancy has been reported to cause congenital malformations in the offspring. Hyperglycemia‐induced teratogenecity is related to the increased oxidative stress and depletion of glutathione (GSH) in fetal tissues.MethodsIn the present study, we have examined the levels of reactive oxygen species (ROS) and peroxide production in the tissues of neonatal rats and in the pancreas of diabetic mother rats. Diabetes was induced one day after pregnancy by a single injection of streptozotocin (60 mg/kg body weight). Different tissues from one‐day‐old neonates and the pancreas from the mothers were collected to study the level of oxidative stress and GSH metabolism.ResultsAn increase in ROS and peroxide production was observed in the pancreas of diabetic rats and in the liver, kidney, brain and skin of the neonates of the diabetic mothers. The catalytic activity of cytochrome P450 2E1 (CYP2E1) was also increased in these tissues from diabetic rats. With the exception of the kidney, the GSH concentration was significantly lower in the tissues of neonates and in the pancreas of diabetic mothers.ConclusionThis reduction in GSH concentration was presumably associated with its increased utilization, due to increased production of peroxides and also due to its reduced regeneration. The study may have an implication in understanding the pathology of diabetic complications in pregnancy and sensitivity toward antioxidant therapy during pregnancy. Copyright © 2004 John Wiley & Sons, Ltd.
Progenitor cells in the adult pancreas
Authors: Holland Andrew M. , Góñez L. Jorge , Harrison Leonard C. 
Published: January 2004

AbstractThe β‐cell mass in the adult pancreas possesses the ability to undergo limited regeneration following injury. Identifying the progenitor cells involved in this process and understanding the mechanisms leading to their maturation will open new avenues for the treatment of type 1 diabetes. However, despite steady advances in determining the molecular basis of early pancreatic development, the identification of pancreatic stem cells or β‐cell progenitors and the molecular mechanisms underlying β‐cell regeneration remain unclear. Recent advances in the directed differentiation of embryonic and adult stem cells has heightened interest in the possible application of stem cell therapy in the treatment of type 1 diabetes. Drawing on the expanding knowledge of pancreas development, β‐cell regeneration and stem cell research, this review focuses on progenitor cells in the adult pancreas as a potential source of β‐cells. Copyright © 2004 John Wiley & Sons, Ltd.
The role of lipids and protein kinase Cs in the pathogenesis of diabetic retinopathy
Authors: Curtis T. M. , Scholfield C. N. 
Published: January 2004

AbstractDiabetic retinopathy is one of the most common complications of diabetes and is a major cause of new blindness in the working‐age population of developed countries. While the exact pathogenic basis of this condition remains ill defined, it is clear that hyperglycaemia is a critical factor in its aetiology. Protein kinase C (PKC) activation is one of the sequelae of hyperglycaemia and it is thought to play an important role in the development of diabetic complications. This review questions the currently held dogma that PKC stimulation in diabetes is solely mediated through the overproduction of palmitate and oleate enriched diacylglycerols. Blood glucose concentrations are closely tracked by changes in the levels of free fatty acids and these, in addition to oxidative stress, may account for the aberrant activation of PKCs in diabetes. Little is known about why PKCs fail to downregulate in diabetes and efforts should be directed towards acquiring such information. Considerable evidence implicates the PKCβ isoform in the pathogenesis of diabetic retinopathy, but other isoforms may also be of relevance. In addition to PKCs, it is evident that novel diacyglycerol‐activated non‐kinase receptors could also play a role in the development of diabetic complications. Therapeutic agents have been developed to inhibit specific PKC isoforms and PKCβ antagonists are currently undergoing clinical trials to test their toxicity and efficacy in suppressing diabetic complications. The likely impact of these drugs in the treatment of diabetic patients is considered. Copyright © 2004 John Wiley & Sons, Ltd.
The effects of price and policy on marijuana use: what can be learned from the Australian experience?
Authors: Williams J. 
Published: January 2004

AbstractThis research examines the responsiveness of the demand for marijuana to changes in its money price and criminal status using data on individuals from the Australian National Drug Strategy's Household Surveys (NDSHS). The results suggest that both the prevalence of marijuana use and the conditional demand for marijuana in the general population are responsive to changes in its money price. Significant differences are found in the effect of price on participation in marijuana use across age‐groups, with participation by youth more price sensitive than participation by older age‐groups. Similarly, the effect of the legal status of marijuana use on the participation decision is found to differ across age‐groups and gender. Specifically, decriminalisation is associated with an increases in the prevalence of use by males over the age of 25. There is no evidence that decriminalisation significantly increases participation in marijuana use by either young males or females, or that decriminalisation increases the frequency of use among marijuana users. Copyright © 2003 John Wiley & Sons, Ltd.
Excess capacity and expense preference behaviour in National Health Systems: an application to the Spanish public hospitals
Authors: Rodríguez‐Álvarez Ana , Knox Lovell C. A. 
Published: January 2004

AbstractThe aim of this paper is to study excess capacity in National Health System (NHS) hospitals, which have the characteristics of a bureaucracy, within a theoretically consistent framework. In this sense, we develop and estimate an empirical model which has not previously been applied to this problem. This model, based on an input distance function, is attractive for at least two reasons. Unlike the production function, the input distance function is valid for multiproduct technologies such as that of hospitals, and in contrast to the cost function it permits testing of the cost minimisation hypothesis and therefore allows expense preference behaviour in the context of NHS hospitals. We present an application to the Spanish public hospital sector and observe persistent allocative inefficiency in variable inputs and overcapitalisation in these hospitals. Hence, our results suggest that this sector is not in long‐run equilibrium and that adjustments in variable inputs and capital equipment investments are necessary to control hospital cost. Copyright © 2003 John Wiley & Sons, Ltd.
Lack of multiplicative transitivity in person trade‐off responses
Authors: Schwarzinger Michaël , Lanoë Jean‐Louis , Nord Erik , Durand‐Zaleski Isabelle 
Published: January 2004

AbstractBackground: The person trade‐off (PTO) is a technique for eliciting preferences for resource allocation across patient groups. In principle PTO responses should satisfy a requirement of multiplicative transitivity, i.e. that if people consider treatment of 1 in state A to be equivalent to treating 10 in state B, and 1 in state B to be equivalent to 10 in state C, then they should find 1 in state A equivalent to 100 in state C. Earlier studies addressing labelled diseases (specific diagnoses), have shown multiplicative intransitivity of the PTO responses. Our purpose was to test multiplicative transitivity in the case of health states described with the EuroQol instrument only and to find a possible framing effect such as the number of persons in the reference intervention.Methods: Forty‐four master degree students were asked to fill in a questionnaire addressing four chronic health states. Their task consisted in (1) ranking the states by severity, (2) valuing each of them by the means of the time trade‐off, and (3) doing the PTO for all the 10 possible pairwise combinations of the four chronic states plus a fatal one. In a subsequent questionnaire the number of persons in the reference intervention in the PTO was increased from 10 to 100. Multiplicative transitivity was studied in subjects who demonstrated a willingness to trade off and consistency in ranking individual values.Results: None of the 39 subjects included satisfied a minimum multiplicative transitivity requirement in PTO responses. Internal consistency was not improved when the PTO involved health states close to each other in terms of severity, nor when the prevention of death was not the reference intervention. For the 22 subjects having answered both types of questionnaire, increasing the number of persons in the reference intervention did not improve multiplicative transitivity.Conclusions: The PTO holds promise as a useful method for determining social preferences for priority setting, inasmuch as it captures distributive concerns that individual utility techniques such as the time trade‐off do not address. But the lack of multiplicative transitivity in PTO responses is unsatisfactory, and ways to reduce this problem need to be explored. Copyright © 2003 John Wiley & Sons, Ltd.
Evidence of range bias in contingent valuation payment scales
Authors: Whynes David K. , Wolstenholme Jane L. , Frew Emma 
Published: January 2004

AbstractThe payment scale format has been widely used in willingness‐to‐pay studies in health care. Concerns have been expressed that the format is, in theory, prone to range bias, although this proposition has not been tested directly. We report the findings of a contingent valuation questionnaire study of colorectal cancer screening, wherein different subjects were provided with payment scales of two different lengths. Whilst the long‐scale instrument included scale values up to £1000, the short‐scale version extended only to £100. After controlling for inter‐sample differences in, for example, income, education and health behaviour, it emerged that the long‐scale instrument produced a mean willingness to pay more than 30% higher than that resulting from the short‐scale version. We believe our findings to be strongly supportive of the likelihood of range bias in payment‐scale instruments, with important consequences for the estimation of both average valuation and consumer surplus. Copyright © 2003 John Wiley & Sons, Ltd.
Managed care and shadow price
Authors: Ma Ching‐to A. 
Published: January 2004

AbstractA managed‐care company must decide on allocating resources of many services to many groups of enrollees. The profit‐maximizing allocation rule is characterized. For each group, the marginal utilities across all services are equalized. The equilibrium has an enrollee group shadow price interpretation. The equilibrium spending allocation can be implemented by letting utilitarian physicians decide on service spending on an enrollee group subject to a budget for the group. Copyright © 2003 John Wiley & Sons, Ltd.
Bayesian estimation of cost‐effectiveness: an importance‐sampling approach
Authors: Heitjan Daniel F. , Li Huiling 
Published: January 2004

AbstractWe describe a method for estimating the cost‐effectiveness of a new treatment compared to a standard, using data from a comparative clinical trial. We quantify the clinical effectiveness as a binary variable indicating success or failure. The underlying statistical model assumes that costs are uncensored and follow separate gamma distributions in each of the groups defined by the four possible combinations of treatment arm and effectiveness outcome. The method is subjectivist, in that it represents prior uncertainty about model parameters with a probability distribution, which we update via Bayes's theorem to produce a posterior distribution. We approximate the posterior by importance sampling, a straightforward simulation method. We illustrate the method with an analysis of cost (derived from resource usage data) and effectiveness (measured by one‐year survival) in a clinical trial in heart disease. The example demonstrates that the method is practical and provides for a flexible data analysis. Copyright © 2003 John Wiley & Sons, Ltd.
Migration of polyethylene debris along well‐fixed cemented implants
Authors: Massin P. , Viguier E. , Flautre B. , Hardouin P. , Astoin E. , Duponchel B. 
Published: January 2004

AbstractImplants, consisting of smooth Inox cylinders, were cemented into the lower femur and upper tibia of nine sheep to study the distal migration of polyethylene particles. Some implants had a titanium‐bead porous coat at the proximal end. These were of three types: In the first type, the porous coat was covered with hydroxyapatite to obtain a bony seal; the second type was prepared for a polymethylmethacrylate seal; in the third type, the porous zone was surrounded by a 2‐mm‐thick space to allow the formation of a fibrous seal. Small polyethylene particles were injected into the knees once a week during the third and fourth months after implantation. The animals were euthanized 2 months later. Major longitudinal sections of the implants and the surrounding bone were examined under a polarized light microscope. Birefringent particles were counted at the cement‐bone and cement‐implant interfaces. Osteolysis was not observed. None of the seals significantly decreased the migration of particles around the cemented part of the implants. Particles were observed in cement fissures and vacuoles. They migrated at both interfaces and in the bone itself. They were visible in marrow spaces between bone trabeculae. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 140–148, 2004
Biological properties of acid etched titanium implants: Effect of sandblasting on bone anchorage
Authors: Szmukler‐Moncler S. , Perrin D. , Ahossi V. , Magnin G. , Bernard J. P. 
Published: January 2004

AbstractThe SLA (sandblasted with large grit and acid etched) surface is a textured surface that has been documented to lead to a rapid and strong implant fixation. The purpose of the present study was to determine the contribution of sandblasting in addition to etching to implant anchorage. It was also aimed to determine if the pits carved during etching alone have a bone‐interlocking capacity that leads to microanchorage between the implant and bone. SLA implants and machined‐and‐acid‐etched (MA) implants were placed in the maxilla of Land Race pigs. After 10 weeks of healing, they were reverse torqued. The reverse torque of the SLA and MA implants was 157.29 ± 38.04 N cm and 105.33 ± 25.12 N cm, respectively. Sandblasting increased bone anchorage by 49.3%; the difference was statistically significant (p = .028). Bone was found attached to both surfaces; bone ingrowth was found in the pits of both surfaces. It is suggested that the two surfaces are able to generate bone interlocking and mechanical coupling at the interface. When finite‐element modeling is performed with these surfaces, it is suggested that the bound mode be used instead of the slip mode. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 149–159, 2004
Formation of defined microporous 3D structures starting from cross‐linked hydrogels
Authors: Barbucci Rolando , Leone Gemma 
Published: January 2004

AbstractA new and simple technique was developed to obtain polysaccharide (hyaluronane, alginate and carboxymethylcellulose) ‐based hydrogels with a defined porous morphology. The technique consists of stratifying a cross‐linked hydrogel on a filter with known pore diameter. CO2 bubbles, produced by the addition of HCl to a porogen salt NaHCO3, are forced to pass through the filter, and they induce the hydrogel to assume a porous morphology. The presence and distribution of pores was confirmed by scanning‐electron microscopy (SEM). A strict correspondence was found between the porosity of the filter and the pore diameter in the hydrogels. Water uptake measurements showed a decreased amount of water taken up by the porous hydrogels compared with the native hydrogels, due to a compacting of the material. An explanation of the porous material properties of Hyal hydrogel was given on the basis of FTIR spectra. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 117–126, 2004
In vivo aging test for a bioactive bone cement consisting of glass bead filler and PMMA matrix
Authors: Shinzato Shuichi , Nakamura Takashi , Kawanabe Keiichi , Kokubo Tadashi 
Published: January 2004

AbstractThe degradation of a new bioactive bone cement (GBC), comprised of an inorganic filler (bioactive MgO‐CaO‐SiO2‐P2O5‐CaF2 glass beads) and an organic matrix [high‐molecular‐weight polymethyl methacrylate (PMMA)], was evaluated in an in vivo aging test. Hardened rectangular specimens (20 × 4 × 3 mm) were prepared from two GBC formulations (containing 50% w/w [GBC50] or 60% w/w [GBC60] bioactive beads) and a conventional PMMA bone cement control (CMW‐1). Initial bending strengths were measured with the use of the three‐point bending method. Specimens of all three cements were then implanted into the dorsal subcutaneous tissue of rats, removed after 3, 6, or 12 months, and tested for bending strength. The bending strengths (MPa) of GBC50 at baseline (0 months), 3, 6, and 12 months were 136 ± 1, 119 ± 3, 106 ± 5 and 104 ± 5, respectively. Corresponding values were 138 ± 3, 120 ± 3, 110 ± 2 and 109 ± 5 for GBC60, and 106 ± 5, 97 ± 5, 92 ± 4 and 88 ± 4 for CMW‐1. Although the bending strengths of all three cements decreased significantly from 0 to 6 months, those of GBC50 and GBC60 did not change significantly thereafter, whereas that of CMW‐1 declined significantly between 6 and 12 months. Thus, degradation of GBC50 and GBC60 does not appear to continue after 6 months, whereas CMW‐1 degrades progressively over 12 months. Moreover, the bending strengths of GBC50 and GBC60 (especially GBC60) were significantly higher than that of CMW‐1 throughout. It is believed that GBC60 is strong enough for use under weight‐bearing conditions and that its mechanical strength is retained in vivo; however, its dynamic fatigue behavior will need assessment before application in the clinical setting. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 132–139, 2004
Bone‐defect healing with calcium‐sulfate particles and cement: An experimental study in rabbit
Authors: Orsini Giovanna , Ricci John , Scarano Antonio , Pecora Gabriele , Petrone Giovanna , Iezzi Giovanna , Piattelli Adriano 
Published: January 2004

AbstractCalcium sulfate (CaS) has been shown to be a reasonable alternative to autogenous bone graft for treating bone lesions in dentistry. The aim of this work was an histological study of the bone healing of defects treated with calcium sulfate in the form of cement or beads, in animal. Eight New Zealand rabbits, weighing about 2.5 Kg were used in this study. In each rabbit, four 6 mm bone defects were created in the tibial metaphysis. The 2 defects in the right tibia were filled with calcium sulfate as cement, while the 2 defects in the left one were filled with calcium sulfate as beads. Four rabbits were killed after respectively 2 and 4 weeks, with an intravenous injection of Tanax, and the block sections, containing the bone defects, were retrieved. A total of 16 defects filled by cement and a total of 16 defects filled by beads were retrieved. The specimens were processed to obtain thin ground sections with the Precise 1 Automated System. In the first phases of healing it was possible to observe an intense osteoblastic activity, and in some areas osteoid matrix was present. After two weeks the calcium sulfate (both cement and beads) was still present, and biological fluids and cells were present inside the material. Newly formed bone surrounded the calcium sulfate and filled about 10% of the defect. After four weeks the calcium sulfate was almost completely resorbed and substituted by new bone. Approximately 34% of the defects were filled by newly formed bone. BEI and XRM evaluations showed the structural components of the filled defects. In none of the specimens were inflammatory cells present. No significant differences were found using both calcium sulfate as cement and beads, and they both have shown a high biocompatibility, appearing to promote newly bone formation in the rabbit model, and they did not induce any untoward effect on the bone regeneration processes. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 199–208, 2004