bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunophenotypic differentiation patterns of normal hematopoiesis in human bone marrow: Reference patterns for age‐related changes and disease‐induced shifts
Authors: van Lochem E.G. , van der Velden V.H.J. , Wind H.K. , te Marvelde J.G. , Westerdaal N.A.C. , van Dongen J.J.M.
Published: June 2004

Background

The abundance of monoclonal antibodies (mAb) and the routine use of quadruple stainings in flow cytometry allow stepwise analysis of bone marrow (BM) samples that are suspected for abnormal hematopoiesis. A screening phase that precedes lineage‐specific classification phases should be sufficient to assess whether the BM has a normal or abnormal composition, as well as to identify the abnormal differentiation lineage.

Methods

For a quick and easy flow cytometric screening of BM samples, we selected six quadruple immunostainings that cover multiple differentiation stages of the B‐cell, monocytic, granulocytic, and erythroid lineages: TdT/CD20/CD19/CD10 and CD45/CD34/CD19/CD22 for B cells, CD34/CD117/CD45/CD13.33 for precursor granulocytic and precursor monocytic cells (myelo/monoblasts), CD14/CD33/CD45/CD34 for monocytic cells, CD16/CD13/CD45/CD11b for granulocytic cells, and CD71/CD235a/CD45/CD117 for erythroid cells.

Results

The six quadruple immunostainings reveal specific staining patterns in normal BM, which allow the recognition of various subpopulations of the respective lineages. These staining patterns can be used as a frame of reference for recognition of normal and abnormal BM development. Examples of normal (age‐related) variations in these otherwise stable staining patterns are presented together with several abnormal differentiation patterns.

Conclusions

Although alternative immunostainings can be used (e.g., including NK‐ and T‐cell markers), we feel that the selected six stainings represent a comprehensive and easy screening phase for quick identification of shifts in the composition of the studied differentiation lineages, reflecting age‐related changes or disease‐induced BM abnormalities. © 2004 Wiley‐Liss, Inc.
Diabetes: insulin resistance and derangements in lipid metabolism. Cure through intervention in fat transport and storage
Authors: Raz Itamar , Eldor Roi , Cernea Simona , Shafrir Eleazar
Published: June 2004

We present multiple findings on derangements in lipid metabolism in type 2 diabetes. The increase in the intracellular deposition of triglycerides (TG) in muscles, liver and pancreas in subjects prone to diabetes is well documented and demonstrated to attenuate glucose metabolism by interfering with insulin signaling and insulin secretion. The obesity often associated with type 2 diabetes is mainly central, resulting in the overload of abdominal adipocytes with TG and reducing fat depot capacity to protect other tissues from utilizing a large proportion of dietary fat. In contrast to subcutaneous adipocytes, the central adipocytes exhibit a high rate of basal lipolysis and are highly sensitive to fat mobilizing hormones, but respond poorly to lipolysis restraining insulin. The enlarged visceral adipocytes are flooding the portal circulation with free fatty acids (FFA) at metabolically inappropriate time, when FFA should be oxidized, thus exposing nonadipose tissues to fat excess. This leads to ectopic TG accumulation in muscles, liver and pancreatic beta‐cells, resulting in insulin resistance and beta‐cell dysfunction. This situation, based on a large number of observations in humans and experimental animals, confirms that peripheral adipose tissue is closely regulated, performing a vital role of buffering fluxes of FFA in the circulation. The central adipose tissues tend to upset this balance by releasing large amounts of FFA. To reduce the excessive fat outflow from the abdominal depots and prevent the ectopic fat deposition it is important to decrease the volume of central fat stores or increase the peripheral fat stores. One possibility is to downregulate the activity of lipoprotein lipase, which is overexpressed in abdominal relatively to subcutaneous fat stores. This can be achieved by gastrointestinal bypass or gastroplasty, which decrease dietary fat absorption, or by direct means that include surgical removal of mesenteric fat. Indirect treatment consists of the compliant application of drastic lifestyle change comprising both diet and exercise and pharmacotherapy that reduces mesenteric fat mass and activity. The first step should be an attempt to effectively induce a lifestyle change. Next comes pharmacotherapy including acarbose, metformin, PPARγ, or PPARγα agonists, statins and orlistat, estrogens in postmenopausal women or testosterone in men. Among surgical procedures, gastric bypass has been proven to produce beneficial results in advance of other surgical techniques, the evidence basis of which still needs strengthening. Copyright © 2004 John Wiley & Sons, Ltd.
Neonatal tolerance revisited again: specific CTL priming in mouse neonates exposed to small numbers of semi‐ or fully allogeneic spleen cells
Authors: Adkins Becky , Jones Monica , Bu Yurong , Levy Robert B.
Published: June 2004

Neonatal and adult mice mount distinct responses to allogeneic cells. Injection of neonates with fully allogeneic cells results in lethal graft‐vs.‐host disease (GVHD), whereas injection of semi‐allogeneic (F1) cells leads to lifelong tolerance to the alloantigens, often marked by specific CTL non‐responsiveness. In contrast, adults injected with the same number of either cell type become primed and develop vigorous anti‐donor CTL activity. One possibility for this differential responsiveness may be developmental immaturity in the CTL arm of the immune system. Recent studies have shown that neonates are capable of mounting mature CTL responses, but only in the presence of strong Th1‐promoting agents. Here, we demonstrate that neonates are competent to develop vigorous MHC class I‐restricted CTL activity in vivo upon exposure to either fully or semi‐allogeneic spleen cells. Specific CTL activity was generated using doses of cells approximately tenfold lower than levels used for the induction of GVHD or tolerance. Thus, the present studies demonstrate that mouse neonates are fully mature in their capacity to develop alloreactive CTL activity, as long as the dose of donor cells is low enough. These results have important implications for the known exposure of human fetuses and infants to small numbers of maternal cells.
The SH3 domain of Tec kinase is essential for its targeting to activated CD28 costimulatory molecule
Authors: Garçon Fabien , Ghiotto Marguerite , Gérard Audrey , Yang Wen‐Chin , Olive Daniel , Nunès Jacques A.
Published: June 2004

The Tec family of protein tyrosine kinases plays an important role in T cell signaling. Tec, the prototypical member of this kinase family, can interact with CD28, which is a costimulatory molecule. However, the regulation of Tec upon CD28 stimulation remains poorly understood. Here we show that CD28–B7‐mediated interactions are likely involved in the relocalization of Tec at the contactzone between T cells and APC. Upon CD28 ligation with specific antibodies or natural ligands, Tec translocates to the plasma membrane where it colocalizes with the CD28 molecule. The Src‐homology 3(SH3) domain of Tec and the two proline‐rich motifs of CD28 are involved in this process. Furthermore, we show that CD28 signaling requires the SH3 domain of Tec as well as proline residues presentin the intracytoplasmic tail of CD28. These results should provide new insights into the complex regulation of Tec kinases in T cells.
Naked RNA vaccine controls tumors with down‐regulated MHC class I expression through NK cells and perforin‐dependent pathways
Authors: Cheng Wen‐Fang , Hung Chien‐Fu , Lee Chien‐Nan , Su Yi‐Ning , Chang Ming‐Cheng , He Liangmei , Wu T.‐C. , Chen Chi‐An , Hsieh Chang‐Yao
Published: June 2004

One of the major issues facing cancer immunotherapy is that many human cancers down‐regulate expression of MHC class I molecules. The understanding of the mechanisms of antitumor effects against tumors with down‐regulated MHC class I will facilitate rational design of vaccines and immunotherapeutic strategies to control such tumors. A naked Sindbis RNA replicon vector (SINrep5) encoding the herpes simplex virus type 1 protein VP22 linked to E7 (SINrep5‐VP22/E7) generated significant antitumor effects against TC‐1 and TC‐1 P3(A15), tumors with down‐regulated MHC class I expression. Naked SINrep5 RNA without the insert or an E7 vaccine also produced antitumor effects against TC‐1 P3(A15) but not TC‐1. Mice vaccinated with any of these naked RNA vaccines generated higher percentages of NK cells. In vivo Ab depletion experiments revealed that NK cells were important for the antitumor effects of naked RNA vaccines against TC‐1 P3(A15) and that the antitumor effects were perforin‐dependent. Poly I:C also increased the percentage of NK cells and generated antitumor effects against the tumors with down‐regulated MHC class I. Thus, the SINrep5‐VP22/E7 naked RNA vaccinecontrols MHC class I‐positive and MHC class I‐down‐regulated tumor cells via different mechanisms, and NK cells play an important role in the antitumor effects generated by naked RNA replicon vaccines.
Prenatal development of the porcine TCR δ repertoire: dominant expression of an invariant T cell receptor Vδ3‐Jδ3 chain
Authors: Holtmeier Wolfgang , Geisel Wiebke , Bernert Kerstin , Butler John E. , Šinkora Marek , Řeháková Zuzana , Šinkora Jiři , Caspary Wolfgang F.
Published: June 2004

The prenatal development of the porcine γ/δ TCR repertoire was studied by complementarity‐determining region 3 (CDR3) spectratyping and sequencing of TRDV1–DV5 transcripts. Specimens from the small and large intestine, spleen, thymus, liver, bone marrow and PBMC from fetal piglets between 38 and 114 days of gestation (DG) were examined. The TCR δ repertoire was highly restricted early in gestation (DG38–DG57) and an invariant TRDV3 transcript, lacking the N/D region, was found in different fetuses throughout gestation and dominated the TRDV3 repertoires of all organs atmid gestation (∼DG55). Near the end of gestation, this invariant TRDV3 transcript was absent from the thymus but was still present, in a less dominant manner, in the intestine and spleen. The average CDR3 length of all Vδ subgroups increased with ontogeny, suggesting an increase in activity of TdT. Thus, the persistence of fetal γ/δ T cells expressing an invariant TRDV3 chain throughout development is especially surprising since TdT is active early in gestation in swine. We speculate that these γ/δ T cells might have been selectively expanded by (self)‐ligands and may have an important function throughout fetal development.
Hydroformylation of 1,5‐Hexadiene Catalyzed by Rhodium Complexes in Supercritical Carbon Dioxide and in Toluene: Effects of Fluorinated Phosphane Ligands and Reaction Conditions
Authors: Fujita Shin‐ichiro , Fujisawa Shinya , Bhanage Bhalchandra M. , Ikushima Yutaka , Arai Masahiko
Published: June 2004

Rhodium‐catalyzed hydroformylation of 1,5‐hexadiene to dialdehydes was investigated in compressed CO2 and in toluene using different fluorinated phosphane compounds as ligands at a temperature of 60 °C. Product yields depend greatly on the ligand used and, of the ligands examined, tris[3,5‐bis(trifluoromethyl)phenyl]phosphane is the most effective for the production of dialdehydes both in supercritical CO2 (scCO2) and in toluene. The total yield of the dialdehydes passes through a minimum at about 9 MPa as the CO2 pressure is increased and increases appreciably as the H2 pressure in scCO2 increases. The effect of the syngas (H2/CO) and H2 pressures on the reaction in scCO2 is different from that in toluene. It has been suggested that scCO2 promotes the hydroformylation reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of Two Branched Fluorescent Receptors and Their Binding Properties for Dicarboxylate Anions
Authors: Zeng Zhen‐Ya , He Yong‐Bing , Wu Jin‐Long , Wei Lan‐Hua , Liu Xin , Meng Ling‐Zhi , Yang Xi
Published: June 2004

Two multi‐armed neutral fluorescent anion receptors (1, 2) bearing multiple amide and thiourea binding sites were synthesized. Study of their UV/Vis and fluorescence spectra indicates that receptors 1 and 2 both form 1:1 complexes with dicarboxylate anions, and that the sensitivity for recognition of dicarboxylate is related to the chain lengths of these dicarboxylate anions. Upon addition of anions, the fluorescence intensities of host solutions were changed significantly. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Heck Coupling Reaction Using Aryl Vinyl Ketones: Synthesis of Flavonoids
Authors: Bianco Armandodoriano , Cavarischia Claudia , Guiso Marcella
Published: June 2004

In our previous communication, an α,β‐unsaturated aryl ketone was employed as the substrate olefin, which underwent arylation in the Heck coupling reaction. The use of this reagent has allowed us to design a new strategy for the synthesis of flavonoids. In this paper, we illustrate the versatility of the procedure, which was used for the preparation of several chalcones. According to our synthetic scheme, several aryl iodides, selected in order to obtain chalcones differently substituted in ring B, were treated with α,β‐unsaturated ketones. All reported syntheses gave high yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Access to Any Site‐Directed Isotopomer of Methionine, Selenomethionine, Cysteine, and Selenocysteine − Use of Simple, Efficient Modular Synthetic Reaction Schemes for Isotope Incorporation
Authors: Siebum Arjan H. G. , Woo Wei Sein , Raap Jan , Lugtenburg Johan
Published: June 2004

Simple modular reaction schemes that allow access to any isotopomer of protected serine and homoserine have been worked out. These systems could be simply converted into cysteine, selenocysteine, homocysteine, homoselenocysteine, the essential amino acid methionine, and selenomethionine by Mitsunobu chemistry. These sulfur‐ and selenium‐containing amino acids fulfil many essential roles in the living organism. In addition, homoserine could be converted in a few steps into optically active L‐vinylglycine. As well as the stable isotopes 13C, 15N, 17O, and 18O, the radioactive isotopes of sulfur, selenium and carbon can also be easily introduced in a site‐directed fashion. In view of the wide scope of the Mitsunobu reaction, we feel that many more important systems with the carbon skeleton of serine and homoserine should be preparable through this basic chemistry in any site‐directed isotopically labeled form. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Solid‐Phase Synthesis of Complex Oligosaccharides Using Azidoglucose as a Glycosyl Acceptor
Authors: Wu Xiangyang , Schmidt Richard R.
Published: June 2004

The solid phase synthesis of oligosaccharides 1−3 was performed on Merrifield resin. These syntheses are based on the hydroxymethylbenzyl benzoate spacer‐linker system and, for regioselective chain extension, the use of O‐glycosyl trichloroacetimidates as glycosyl donors containing temporary O‐Fmoc protection. The important lactosamine‐containing oligosaccharides 1−3 are accessible in excellent yields by using a 2‐azidoglucose residue as the glucosamine building block adjacent to the spacer‐linker system. Only standard amounts of the glycosyl donor are employed in this solid phase oligosaccharide synthesis and we did not have to resort to any capping procedures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Dihaloadamantanes: Ring Closure versus Rearrangement or Halogen‐Displacement Reactions
Authors: Mlinarić‐Majerski Kata , Veljković Jelena , Kaselj Mira , Marchand Alan P.
Published: June 2004

Three dihaloadamantanes [i.e., 2‐bromo‐1‐(chloromethyl)adamantane (1), 1‐(bromomethyl)‐2‐chloroadamantane (2) and 2‐bromo‐1‐(bromomethyl)adamantane (3)] were synthesized, and their corresponding ring‐closing reactions, performed by using Na metal or alkyllithium reagents, were studied. Compound 1 reacted with Na in toluene or in tetraglyme to afford 1,2‐methanoadamantane (4) as the major product. However, the corresponding reactions, when performed by using 2 and 3 as substrates, produced methyladamantane (5) or 4‐methyleneprotoadamantane (6) as the major reaction products. The corresponding reactions of 1 and 2 with tBuLi or nBuLi afforded small quantities of 4, 5 and 6 along with the corresponding monohalides, that is, 1‐(chloromethyl)adamantane (7) and 2‐chloro‐1‐methyladamantane (8), which constituted the major products of these reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Fast Access to Non‐Symmetrically Substituted 1,3‐Alternate Conformers of Calix[4]arenes
Authors: Kleij Arjan W. , Prados Pilar , de Mendoza Javier
Published: June 2004

A simple and direct protocol is reported for the synthesis of the first non‐symmetrically substituted 1,3‐alternate conformers of calix[4]arenes by selective mono‐deacylation of a tribenzoyl precursor under basic conditions, followed by dialkylation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Equivalent viscous damping for modeling inelastic impacts in earthquake pounding problems
Authors: Anagnostopoulos Stavros A.
Published: June 2004

In studies of earthquake‐induced pounding between adjacent structures, spring–dashpot elements are often used to simulate the impacts. In this brief paper an equation is derived expressing the dashpot constant as a function of the coefficient of restitution, in terms of which inelastic impacts of colliding simple bodies have usually been described. Copyright © 2004 John Wiley & Sons, Ltd.
A modal pushover analysis procedure to estimate seismic demands for unsymmetric‐plan buildings
Authors: Chopra Anil K. , Goel Rakesh K.
Published: June 2004

An Erratum has been published for this article in Earthquake Engng. Struct. Dyn. 2004; 33:1429.

Based on structural dynamics theory, the modal pushover analysis (MPA) procedure retains the conceptual simplicity of current procedures with invariant force distribution, now common in structural engineering practice. The MPA procedure for estimating seismic demands is extended to unsymmetric‐plan buildings. In the MPA procedure, the seismic demand due to individual terms in the modal expansion of the effective earthquake forces is determined by non‐linear static analysis using the inertia force distribution for each mode, which for unsymmetric buildings includes two lateral forces and torque at each floor level. These ‘modal’ demands due to the first few terms of the modal expansion are then combined by the CQC rule to obtain an estimate of the total seismic demand for inelastic systems. When applied to elastic systems, the MPA procedure is equivalent to standard response spectrum analysis (RSA). The MPA estimates of seismic demand for torsionally‐stiff and torsionally‐flexible unsymmetric systems are shown to be similarly accurate as they are for the symmetric building; however, the results deteriorate for a torsionally‐similarly‐stiff unsymmetric‐plan system and the ground motion considered because (a) elastic modes are strongly coupled, and (b) roof displacement is underestimated by the CQC modal combination rule (which would also limit accuracy of RSA for linearly elastic systems). Copyright © 2004 John Wiley & Sons, Ltd.
Elastic and inelastic drift performance optimization for reinforced concrete buildings under earthquake loads
Authors: Chan Chun‐Man , Zou Xiao‐Kang
Published: June 2004

This paper presents an effective optimization technique for the elastic and inelastic drift performance design of reinforced concrete buildings under response spectrum loading and pushover loading. Attempts have been made to develop an automatic optimal elastic and inelastic drift design of concrete framework structures. The entire optimization procedure can be divided into elastic design optimization and inelastic design optimization. Using the principle of virtual work, the elastic drift response generated by the response spectrum loading and the inelastic drift response produced by the non‐linear pushover loading can be explicitly expressed in terms of element sizing design variables. The optimization methodology for the solution of the explicit design problem of buildings is fundamentally based on the Optimality Criteria approach. One ten‐story, two‐bay building frame example is presented to illustrate the effectiveness and practicality of the proposed optimal design method. While rapid convergence in a few design cycles is found in the elastic optimization process, relatively slow but steady and smooth convergence of the optimal performance‐based design is found in the inelastic optimization process. Copyright © 2004 John Wiley & Sons, Ltd.
Comparing the adequacy of alternative ground motion intensity measures for the estimation of structural responses
Authors: Giovenale Paolo , Cornell C. Allin , Esteva Luis
Published: June 2004

Practical methods for the probability‐based seismic assessment of structures make use of estimates of demands produced by earthquakes of different intensities. The uncertainties associated with these estimates are highly dependent on the variable adopted as the intensity measure (IM, e.g., PGA, spectral acceleration, etc.). This generates the need to compare the efficiency of an originally adopted IMwith that of a new candidate. This implies comparing the dispersion of the demand measure (DM, e.g., maximum interstorey drift ratio, ductility demand, etc.) conditional to each of the two IMs. In order to obtain the demand estimates in a conventional way, a full set of dynamic response analyses should be performed for each IM under scrutiny, i.e., multiple records scaled at several fixed values of each IM.

The procedure developed here serves to accelerate this comparison avoiding the effort required to evaluate the dynamic responses of the structure for all the ground motion time histories considered every time that a new IM is adopted. For this purpose, use is made of available results of analyses performed for a different (i.e., the original) IM. Two methods are proposed: the direct method involves performing a regression of the results obtained from the original analyses, taking the candidate IM as the independent variable. The indirect method involves rebuilding the probability density function of the DM given a defined value of the candidate IM by means of the total probability theorem, using the results of the original analyses and certain data relating the two IMs.

The proposed methods have been tested by application to several SDOF systems with different periods and different cyclic‐response backbone curves. The conditions affecting their approximation are explored, and some criteria to improve them are identified. The procedure can also be used to determine the optimum value of a parameter to be used in a parameter‐based IM. Copyright © 2004 John Wiley & Sons, Ltd.
ZnT‐1 expression in astroglial cells protects against zinc toxicity and slows the accumulation of intracellular zinc
Authors: Nolte Christiane , Gore Ariel , Sekler Israel , Kresse Wolfgang , Hershfinkel Michal , Hoffmann Anja , Kettenmann Helmut , Moran Arie
Published: June 2004

Zinc ions are emerging as an important factor in the etiology of neurodegenerative disorders and in brain damage resulting from ischemia or seizure activity. High intracellular levels of zinc are toxic not only to neurons but also to astrocytes, the major population of glial cells in the brain. In the present study, the role of ZnT‐1 in reducing zinc‐dependent cell damage in astrocytes was assessed. Zinc‐dependent cell damage was apparent within 2 h of exposure to zinc, and occurred within a narrow range of ∼200 μM. Pretreatment with sublethal concentrations of zinc rendered astrocytes less sensitive to toxic zinc levels, indicating that preconditioning protects astrocytes from zinc toxicity. Fluorescence cell imaging revealed a steep reduction in intracellular zinc accumulation for the zinc‐pretreated cells mediated by L‐type calcium channels. Heterologous expression of ZnT‐1 had similar effects; intracellular zinc accumulation was slowed down and the sensitivity of astrocytes to toxic zinc levels was reduced, indicating that this is specifically mediated by ZnT‐1 expression. Immunohistochemical analysis demonstrated endogenous ZnT‐1 expression in cultured astroglia, microglia, and oligodendrocytes. Pretreatment with zinc induced a 4‐fold increase in the expression of the putative zinc transporter ZnT‐1 in astroglia as shown by immunoblot analysis. The elevated ZnT‐1 expression following zinc priming or after heterologous expression of ZnT‐1 may explain the reduced zinc accumulation and the subsequent reduction in sensitivity toward toxic zinc levels. Induction of ZnT‐1 may play a protective role when mild episodes of stroke or seizures are followed by a massive brain insult. © 2004 Wiley‐Liss, Inc.
Gangliosides activate microglia via protein kinase C and NADPH oxidase
Authors: Min Kyoung‐Jin , Pyo Han‐Kyung , Yang Myung‐Soon , Ji Kyung‐Ae , Jou Ilo , Joe Eun‐Hye
Published: June 2004

Microglia, the major immune effector cells in the central nervous system, are activated when the brain suffers injury. A number of studies indicate that gangliosides activate microglia. However, the signaling mechanisms involved in microglial activation are not yet to be elucidated. Our results show that gangliosides induce the expression of interleukin (IL)‐1β, tumor necrosis factor‐α (TNF‐α), and inducible nitric oxide synthase (iNOS) in rat brain microglia and BV2 murine microglia via protein kinase C (PKC) and NADPH oxidase. Expression of IL‐1β, TNF‐α, and iNOS in ganglioside‐treated cells was significantly reduced in the presence of inhibitors of PKC (GF109203X, Gö6976, Ro31‐8220, and rottlerin) and NADPH oxidase (diphenyleneiodonium chloride [DPI]). In response to gangliosides, PKC‐α, βII, and δ and NADPH oxidase p67phox translocated from the cytosol to the membrane. ROS generation was also activated within 5 min of ganglioside treatment. Ganglioside‐induced ROS generation was blocked by PKC inhibitors. Furthermore, ganglioside‐induced activation of NF‐κB, an essential transcription factor that mediates the expression of IL‐1β, TNF‐α, and iNOS, was reduced in the presence of GF109203X and DPI. Our results collectively suggest that gangliosides activate microglia via PKC and NADPH oxidase, which regulate activation of NF‐κB. © 2004 Wiley‐Liss, Inc.
Dehydroepiandrosterone regulates astroglia reaction to denervation of olfactory glomeruli
Authors: Hoyk Zsófia , Párducz Árpád , Garcia‐Segura Luis Miguel
Published: June 2004

Effects of dehydroepiandrosterone (DHEA) on glial reactions of the peripherally denervated olfactory bulb were studied in adult male rats. Denervation was achieved by destroying the olfactory mucosa with ZnSO4 (0.17 M) irrigation of the nasal cavities. In one series of experiments, chronic DHEA treatment was applied (daily injections for 7 days, i.p., 10 mg/kg b.w. and 25 mg/kg b.w.); in the other series of experiments, animals received a single injection of DHEA (i.p., 10 mg/kg b.w., 25 mg/kg b.w. and 50 mg/kg b.w.) 2 h following ZnSO4 treatment. To determine whether DHEA conversion to estradiol was involved in the mechanism of DHEA action on glia, a third series of experiments was carried out in which the aromatase inhibitor fadrozole (4.16 mg/ml) was administered using subcutaneously implanted osmotic minipumps. Rats were killed on day 7 after chemical denervation, and the reaction of glial cells was monitored within the olfactory bulb, using GFAP and vimentin immunohistochemistry. Qualitative changes in GFAP expression were analyzed by Western blot. Chronic DHEA treatment with both doses (10 mg/kg b.w. and 25 mg/kg b.w.) and acute DHEA treatment with the highest dose applied (50 mg/kg b.w.), inhibited the increase in GFAP expression induced by the denervation of the olfactory bulb. Furthermore, GFAP and vimentin immunostaining in the glomerular layer of the olfactory bulb were diminished in the denervated and DHEA treated groups. However, when DHEA treatment was combined with fadrozole administration, such a decrease in GFAP expression could not be detected in the chemically denervated olfactory bulb. These findings indicate that DHEA, depending on the dose applied and the mode of administration, attenuates glial reaction to denervation and may regulate glial plasticity in the olfactory glomeruli. These effects are likely to be mediated at least in part by the conversion of DHEA to estradiol. © 2004 Wiley‐Liss, Inc.
Evidence that the branched‐chain α‐keto acids accumulating in maple syrup urine disease induce morphological alterations and death in cultured astrocytes from rat cerebral cortex
Authors: Funchal Cláudia , Gottfried Carmem , Vieira De Almeida Lúcia Maria , Wajner Moacir , Pessoa‐Pureur Regina
Published: June 2004

Severe neurological symptoms, cerebral edema, and atrophy are common features of the inherited metabolic disorder maple syrup urine disease (MSUD). However, the pathomechanisms involved in the neuropathology of this disease are not well established. In this study, we investigated the effects of the branched‐chain keto acids (BCKA) α‐ketoisocaproic (KIC), α‐ketoisovaleric (KIV), and α‐keto–β–methylvaleric (KMV), which accumulate in MSUD, on astrocyte morphology and cytoskeleton reorganization. Cultured astrocytes from cerebral cortex of neonatal rats were exposed to various concentrations of the BCKA and cell morphology was studied. We observed that these cells changed their usual polygonal morphology when exposed to BCKA, leading to the appearance of fusiform or process‐bearing cells. Furthermore, longer exposures to the BCKA elicited cell death at all concentrations studied, attaining massive death at the highest concentrations. Immunocytochemistry with anti‐actin or anti‐GFAP antibodies revealed that the BCKA induced reorganization of actin and GFAP cytoskeleton. In addition, astrocytes treated with lysophosphatidic acid, an upstream activator of the RhoA GTPase pathway, totally prevented the morphological alterations and cytoskeletal reorganization induced by KIV, indicating that this effect could be mediated by the RhoA signaling pathway. Furthermore, the effects of BCKA on astrocyte morphology were prevented by creatine. In addition, creatine kinase activity was inhibited by KIC and KIV; this inhibition was prevented by creatine, indicating that these keto acids compromise brain energy metabolism. Considering that astroglial cells are critical to brain development and functioning, it is conceivable that alterations of the actin network by BCKA may have important implications in astrocytic function and possibly in the pathogenesis of the neurological dysfunction and brain damage of MSUD patients. © 2004 Wiley‐Liss, Inc.
Money for health: the equivalent variation of cardiovascular diseases
Authors: Groot Wim , van den Brink Henriëtte Maassen , Plug Erik
Published: June 2004

This paper introduces a new method to calculate the extent to which individuals are willing to trade money for improvements in their health status. An individual welfare function of income (WFI) is applied to calculate the equivalent income variation of health impairments. We believe that this approach avoids various drawbacks of alternative willingness‐to‐pay methods. The WFI is used to calculate the equivalent variation of cardiovascular diseases. It is found that for a 25 year old male the equivalent variation of a heart disease ranges from €114 000 to €380 000 depending on the welfare level. This is about €10 000–€30 000 for an additional life year. The equivalent variation declines with age and is about the same for men and women. The estimates further vary by discount rate chosen. The estimates of the equivalent variation are generally higher than the money spent on most heart‐related medical interventions per QALY. The cost‐benefit analysis shows that for most interventions the value of the health benefits exceeds the costs. Heart transplants seem to be too costly and only beneficial if patients are young. Copyright © 2004 John Wiley & Sons, Ltd.
On the interpretation of a concentration index of inequality
Authors: Koolman Xander , van Doorslaer Eddy
Published: June 2004

This paper aims to add a more intuitive understanding to the concept of a concentration index for measuring relative inequality with an application of health‐related measures by income. A new redistribution interpretation and an existing redistribution interpretation of the Gini are presented and applied to the concentration index. Both indicate the share of the total amount of any variable that needs redistributing in a particular way from rich to poor (or vice versa) to achieve a concentration index equal to zero. The characteristics of these redistribution schemes are compared. The paper also draws attention to the relationship between a concentration index, a correlation coefficient with relative income rank and a coefficient of variation of the variable of interest. These relationships are illustrated using data on inequality in dental care utilisation in European countries taken from the European Community Household Panel survey. Copyright © 2004 John Wiley & Sons, Ltd.
Economic valuation of informal care: the contingent valuation method applied to informal caregiving
Authors: van denBerg Bernard , Brouwer Werner , Exel Job van , Koopmanschap Marc
Published: June 2004

This paper reports the results of the application of the contingent valuation method (CVM) to determine a monetary value of informal care. We discuss the current practice in valuing informal care and a theoretical model of the costs and benefits related to the provision of informal care. In addition, we developed a survey in which informal caregivers' willingness to accept (WTA) to provide an additional hour of informal care was elicited. This method is better than normally recommended valuation methods able to capture the heterogeneity and dynamics of informal care.

Data were obtained from postal surveys. A total of 153 informal caregivers and 149 care recipients with rheumatoid arthritis returned a completed survey. Informal caregivers reported a mean WTA to provide a hypothetical additional hour of informal care of 9.52 Euro (n=124). Many hypotheses derived from the theoretical model and the literature were supported by the data.

CVM is a promising alternative for existing methods like the opportunity cost method and the proxy good method to determine a monetary value of informal care that can be incorporated in the numerator of any economic evaluation. Copyright © 2004 John Wiley & Sons, Ltd.
Valuation of the risk of SARS in Taiwan
Authors: Liu Jin‐Tan , Hammitt James K. , Wang Jung‐Der , Tsou Meng‐Wen
Published: June 2004

Two surveys conducted in Taiwan during the spring 2003 severe acute respiratory syndrome (SARS) epidemic reveal a high degree of concern about the threat posed by SARS to Taiwan and its residents, although respondents believe they are knowledgeable about the risk of SARS and that it is susceptible to individual control. Willingness to pay (WTP) to reduce the risk of infection and death from SARS is elicited using contingent valuation methods. Estimated WTP is high, implying values per statistical life of US$3 to 12 million. While consistent with estimates for high‐income countries, these values are substantially larger than previous estimates for Taiwan and may be attributable to the high degree of concern about SARS at the time the data were collected. Copyright © 2004 John Wiley & Sons, Ltd.
Comparing costing results in across country economic evaluations: the use of technology specific purchasing power parities
Authors: Wordsworth Sarah , Ludbrook Anne
Published: June 2004

The number of economic evaluations conducted on a multinational basis is increasing. Therefore, techniques are required to compare the results of such studies in a meaningful manner. This paper explores different approaches to comparing across country cost data applied to a European study of dialysis therapy for end‐stage renal disease. A price and volume index is created at the level of the individual health care technology and compared to an exchange rate conversion and published purchasing power parities (PPPs). Both exchange rate and PPP conversions when published rates are used fail to accurately reflect the true resource use of the applied health care example. These differences can be related to specific issues of input mix and price variation. Alternatively, the use of technology specific PPPs provided a more robust approach for international comparisons and also have the potential for use in multi‐centre economic evaluations within the same country. Copyright © 2004 John Wiley & Sons, Ltd.
Assessing generalisability by location in trial‐based cost‐effectiveness analysis: the use of multilevel models
Authors: Manca Andrea , Rice Nigel , Sculpher Mark J. , Briggs Andrew H.
Published: June 2004

An Erratum has been published for this article in Health Economics 14(5) 2005, 486.

Cost‐effectiveness analysis (CEA) in health care is increasingly conducted alongside multicentre and multinational randomised controlled clinical trials (RCTs). The increased use of stochastic CEA is designed to account for between‐patient sampling variability in cost‐effectiveness data assuming that observations are independently distributed. However, between‐location variability in cost‐effectiveness may result if there is a hierarchical structure in the data; that is, if there is correlation in costs and outcomes between patients recruited in particular locations. This may be expected in multi‐location trials given that centres and countries often differ in factors such as clinical practice, patient case‐mix and the unit costs of delivering health care. A failure to acknowledge this feature may lead to misleading conclusions in a trial‐based economic study. Multilevel modelling (MLM) is an analytical framework that can be used to handle hierarchical cost‐effectiveness data. Using data from a recently conducted economic analysis, this paper shows how multilevel modelling can be used to obtain (a) more appropriate estimates of the population average incremental cost‐effectiveness and associated standard errors compared to standard stochastic CEA; and (b) location‐specific estimates of incremental cost‐effectiveness which can be used to explore appropriately the variability between centres/countries of the cost‐effectiveness results. Copyright © 2004 John Wiley & Sons, Ltd.
Risk aversion and uncertainty in cost‐effectiveness analysis: the expected‐utility, moment‐generating function approach
Authors: Elbasha Elamin H.
Published: June 2004

The availability of patient‐level data from clinical trials has spurred a lot of interest in developing methods for quantifying and presenting uncertainty in cost–effectiveness analysis (CEA). Although the majority has focused on developing methods for using sample data to estimate a confidence interval for an incremental cost–effectiveness ratio (ICER), a small strand of the literature has emphasized the importance of incorporating risk preferences and the trade‐off between the mean and the variance of returns to investment in health and medicine (mean‐variance analysis).

This paper shows how the exponential utility–moment‐generating function approach is a natural extension to this branch of the literature for modelling choices from healthcare interventions with uncertain costs and effects. The paper assumes an exponential utility function, which implies constant absolute risk aversion, and is based on the fact that the expected value of this function results in a convenient expression that depends only on the moment‐generating function of the random variables. The mean‐variance approach is shown to be a special case of this more general framework.

The paper characterizes the solution to the resource allocation problem using standard optimization techniques and derives the summary measure researchers need to estimate for each programme, when the assumption of risk neutrality does not hold, and compares it to the standard incremental cost–effectiveness ratio. The importance of choosing the correct distribution of costs and effects and the issues related to estimation of the parameters of the distribution are also discussed. An empirical example to illustrate the methods and concepts is provided. Copyright © 2004 John Wiley & Sons, Ltd.
Using multilevel models for assessing the variability of multinational resource use and cost data
Authors: Grieve Richard , Nixon Richard , Thompson Simon G. , Normand Charles
Published: June 2004

Multinational economic evaluations often calculate a single measure of cost‐effectiveness using cost data pooled across several countries. To assess the validity of pooling international cost data the reasons for cost variation across countries need to be assessed. Previously, ordinary least‐squares (OLS) regression models have been used to identify factors associated with variability in resource use and total costs. However, multilevel models (MLMs), which accommodate the hierarchical structure of the data, may be more appropriate. This paper compares these different techniques using a multinational dataset comprising case‐mix, resource use and cost data on 1300 stroke admissions from 13 centres in 11 European countries. OLS and MLMs were used to estimate the effect of patient and centre‐level covariates on the total length of hospital stay (LOS) and total cost. MLMs with normal and gamma distributions for the data within centres were compared. The results from the OLS model showed that both patient and centre‐level covariates were associated with LOS and total cost. The estimates from the MLMs showed that none of the centre‐level characteristics were associated with LOS, and the level of spending on health was the centre‐level variable most highly associated with total cost. We conclude that using OLS models for assessing international variation can lead to incorrect inferences, and that MLMs are more appropriate for assessing why resource use and costs vary across centres. Copyright © 2004 John Wiley & Sons, Ltd.
Explaining income‐related inequalities in doctor utilisation in Europe
Authors: Doorslaer Eddy van , Koolman Xander , Jones Andrew M.
Published: June 2004

This paper presents new international comparative evidence on the factors driving inequalities in the use of GP and specialist services in 12 EU member states. The data are taken from the 1996 wave of the European Community Household Panel (ECHP). We examine two types of utilisation (the probability of a visit and the conditional number of positive visits) for two types of medical care: general practitioner and medical specialist visits using probit, truncated Negbin and generalised Negbin models. We find little or no evidence of income‐related inequity in the probability of a GP visit in these countries. Conditional upon at least one visit, there is even evidence of a somewhat pro‐poor distribution. By contrast, substantial pro‐rich inequity emerges in virtually every country with respect to the probability of contacting a medical specialist. Despite their lower needs for such care, wealthier and higher educated individuals appear to be much more likely to see a specialist than the less well‐off. This phenomenon is universal in Europe, but stronger in countries where either private insurance cover or private practice options are offered to purchase quicker and/or preferential access. Pro‐rich inequity in subsequent visits adds to this access inequity but appears more related to regional disparities in utilisation than to other factors. Despite decades of universal and fairly comprehensive coverage in European countries, utilisation patterns suggest that rich and poor are not treated equally. Copyright © 2004 John Wiley & Sons, Ltd.
Efficacy of Venlafaxine ER in patients with social anxiety disorder: a double‐blind, placebo‐controlled, parallel‐group comparison with paroxetine
Authors: Allgulander Christer , Mangano Richard , Zhang Jun , Dahl Alv A. , Lepola Ulla , Sjödin Ingemar , Emilien Gerard
Published: June 2004

This study evaluated the anxiolytic efficacy, safety and tolerability of a flexible dose of venlafaxine extended release (ER) compared with placebo and paroxetine in the short‐term treatment of generalized social anxiety disorder (SAD). Adult outpatients with generalized SAD (n = 434) were randomized to receive capsules of venlafaxine ER 75 mg to 225 mg/day, paroxetine 20 mg to 50 mg/day, or placebo for 12 weeks. The primary efficacy variable was the Liebowitz social anxiety scale total score. Secondary efficacy variables included the patient‐rated social phobia inventory and the proportion of responders in each group (a responder was defined as having a clinical global impression‐improvement score of 1 or 2). Treatment with venlafaxine ER was associated with significantly greater improvement than treatment with placebo for all primary and secondary efficacy variables (p < 0.05). No significant differences in primary or secondary efficacy variables were observed between the venlafaxine ER and paroxetine groups. The week 12 response rates were 69%, 66% and 36% for the venlafaxine ER, paroxetine and placebo groups, respectively. Both active treatments were generally well tolerated and were associated with a similar incidence of adverse events. This study shows that venlafaxine ER is an effective, safe and well‐tolerated drug treatment for SAD. Copyright © 2004 John Wiley & Sons, Ltd.
RGD‐modified anti‐CD3 antibodies redirect cytolytic capacity of cytotoxic T lymphocytes toward αvβ3‐expressing endothelial cells
Authors: Schraa Astrid J. , Kok Robbert J. , Botter Sander M. , Withoff Sebo , Meijer Dirk K.F. , de Leij Lou F.M.H. , Molema Grietje
Published: June 2004

To redirect the lytic activity of cytotoxic T lymphocytes (CTL) toward tumor vascular endothelial cells, we prepared bifunctional proteins with specificity for both αvβ3 and CD3. Monocyclic RGD peptides (cRGDfK) were covalently coupled to an anti‐CD3 monoclonal antibody at different peptide:protein ratios. The resulting RGDpep‐anti‐CD3 conjugates bound specifically to αvβ3‐expressing endothelial cells. Displacement studies with radiolabeled αvβ3 ligand demonstrated that the αvβ3 binding affinity of RGDpep‐anti‐CD3 conjugates was elevated as compared to the non‐conjugated RGDpep. IC50 values ranged from 150–1.1 nM, depending on the amount of coupled RGDpep molecules per antibody molecule. RGD modification did not affect the ability of anti‐CD3 antibodies to bind to CTL. Furthermore, RGDpep‐anti‐CD3 was fully capable of activating T cells upon CD3 binding as was shown in a Jurkat/NFAT reporter‐gene activation assay. All RGDpep‐anti‐CD3 conjugates were able to induce RGDpep, CD3‐dependent lysis of human primary endothelial cells by anti‐CD3/IL‐2 activated human peripheral blood mononuclear cells (PBMC), with a significant induction of cytotoxicity observed at an E/T ratio as low as 10. Redirecting cytolytic activity reached up to 50% cytotoxicity using the conjugate with the highest RGD peptide load. Combining the good accessibility of tumor blood vessel endothelium for CTL with the efficiency of target cell killing warrants further investigations on anti‐tumor effects of this type of conjugates in vivo. © 2004 Wiley‐Liss, Inc.