bluuebunny/crossref_metadata_2025 huggingface dataset:
Conditional multipoint linkage analysis using affected sib pairs: An alternative approach
Authors: Chiu Yen‐Feng , Liang Kung‐Yee
Published: January 2004

Recently, Liang et al. ([2001b] Genet. Epidemiol. 21:105–122) proposed a conditional approach to assess linkage evidence on the target region by incorporating linkage information from an unlinked (reference) region using allele shared IBD (identity‐by‐decent) from affected sib pairs. This is carried out by conditioning on the IBD sharing value at the estimated trait locus of the reference region. Since markers considered are typically non‐fully informative, the IBD sharing at each marker needs to be estimated (or imputed). In this report, we propose an alternative approach to deal with the IBD sharing in the reference region. This new approach makes full use of the observed data without having to categorize the imputed IBD sharing as needed in Liang et al. ([2001b] Genet. Epidemiol. 21:105–122). We compare these two approaches by simulating data from a variety of two‐locus models including heterogeneity, additive and multiplicative with either fully informative markers or non‐fully informative markers. The performance of both approaches is quite comparable showing consistent estimates of the trait locus and key genetic parameters. Genet Epidemiol 26:108–115, 2004. © 2004 Wiley‐Liss, Inc.
Using simulation‐based inference with panel data in health economics
Authors: Contoyannis Paul , Jones Andrew M. , Leon‐Gonzalez Roberto
Published: January 2004

Panel datasets provide a rich source of information for health economists, offering the scope to control for individual heterogeneity and to model the dynamics of individual behaviour. However the qualitative or categorical measures of outcome often used in health economics create special problems for estimating econometric models. Allowing a flexible specification of the autocorrelation induced by individual heterogeneity leads to models involving higher order integrals that cannot be handled by conventional numerical methods. The dramatic growth in computing power over recent years has been accompanied by the development of simulation‐based estimators that solve this problem. This review uses binary choice models to show what can be done with conventional methods and how the range of models can be expanded by using simulation methods. Practical applications of the methods are illustrated using data on health from the British Household Panel Survey (BHPS). Copyright © 2003 John Wiley & Sons, Ltd.
Does problem drinking affect employment? Evidence from England
Authors: MacDonald Ziggy , Shields Michael A.
Published: January 2004

In this paper, we use data from the Health Survey of England to show that problem drinking is negatively and significantly associated with the probability of being in work, once the endogenous relationship between these outcomes is accounted for. Being a problem drinker leads to a substantial reduction in the probability of working by between 7 and 31%, the former figure being roughly equivalent to the positive effect of having a degree relative to no qualifications in our data. This finding is robust to a variety of identifying restrictions and definitions of problem drinking. Moreover, we find that problem drinking defined by the observed psychological and physical symptoms of alcohol is an important predictor of employment, and allows for the fact that individuals differ in their tolerance or susceptibility to alcohol. Our results suggest that there may be important labour market benefits from public health policies aimed at the prevention and treatment of problem drinking. Copyright © 2003 John Wiley & Sons, Ltd.
Real exchange rate fluctuations and monetary shocks: a revisit
Authors: Chen Shiu‐Sheng
Published: January 2004

In this paper, I first estimate a structural VAR model by following Clarida and Gali (1994) and obtain results indicating that the variance of real exchange rates can be attributed more to monetary shocks when the sample span is extended. In order to further investigate this aspect, I then employ a VAR model with long‐run US–UK annual data from 1889 to 1995. According to the variance decompositions, I find that monetary shocks can explain nearly 50% of real exchange rate variance in the long‐run sample periods. All the evidence suggests that monetary shocks are indeed more important in a larger sample set. Copyright © 2003 John Wiley & Sons, Ltd.
Do higher solvency ratios reduce the costs of bailing out insured banks?
Authors: Eastwood Robert K.
Published: January 2004

The relationship between solvency constraints and bank behaviour in the presence of fixed rate deposit insurance is investigated. A rise in the minimum solvency ratio does not necessarily reduce the adverse consequences of moral hazard: bank efficiency may fall and expected bailout costs may rise. Such outcomes are possible even if credit risk is purely systemic. Similar results obtain in respect of level increases in bank capital, tangible or intangible, although in this case purely systemic risk excludes perverse outcomes. Copyright © 2003 John Wiley & Sons, Ltd.
Inflation targeting or fear of floating in disguise: the case of Mexico
Authors: Ball Christopher P. , Reyes Javier
Published: January 2004

This paper uses simple analytics to show the similarities and differences between inflation targeting and fear of floating in emerging markets. The analytics provide well‐defined predictions for the behaviour of exchange rates and relevant monetary variables under both regimes. This allows us to distinguish clearly one regime from another and empirically test whether or not a country that targets inflation also exhibits a fear of floating.

We analyse the recent experience in Mexico where the authorities now claim to be following an inflation targeting regime. Mexico is also one of the countries claimed to exhibit a fear of floating. Using data from Banco de México, we first confirm that by standard measures Mexico exhibits fear of floating. Second, we show that Mexico is inflation targeting and discuss the relationship and test for a distinction between the two. Finally, we conclude by discussing our results and their implications for other emerging market inflation targeters. Copyright © 2004 John Wiley & Sons, Ltd.
Transmission of equity returns and volatility in Asian developed and emerging markets: a multivariate GARCH analysis
Authors: Worthington Andrew , Higgs Helen
Published: January 2004

This paper examines the transmission of equity returns and volatility among Asian equity markets and investigates the differences that exist in this regard between the developed and emerging markets. Three developed markets (Hong Kong, Japan and Singapore) and six emerging markets (Indonesia, Korea, Malaysia, the Philippines, Taiwan and Thailand) are included in the analysis. A multivariate generalized autoregressive conditional heteroskedasticity (MGARCH) model is used to identify the source and magnitude of spillovers. The results generally indicate the presence of large and predominantly positive mean and volatility spillovers. Nevertheless, mean spillovers from the developed to the emerging markets are not homogeneous across the emerging markets, and own‐volatility spillovers are generally higher than cross‐volatility spillovers for all markets, but especially for the emerging markets. Copyright © 2003 John Wiley & Sons, Ltd.
Can regime‐switching models reproduce the business cycle features of US aggregate consumption, investment and output?
Authors: Clements Michael P. , Krolzig Hans‐Martin
Published: January 2004

The ability of Markov‐switching (MS) autoregressive models to replicate selected classical business cycle features found in US post‐war consumption, investment and output is compared to that of linear models. Univariate MS models appear to offer more dynamically parsimonious representations, but generally are unable to reproduce features missed by linear models. In the multivariate models, some cointegration restrictions were found to have a crucial impact, and the ability of models that imposed cointegration to reproduce business cycle features was enhanced by Markov switching. Copyright © 2004 John Wiley & Sons, Ltd.
International real interest rate differentials, purchasing power parity and the behaviour of real exchange rates: the resolution of a conundrum
Authors: Taylor Mark P. , Sarno Lucio
Published: January 2004

According to one strand of the international finance literature, market efficiency implies that the real exchange rate follows a martingale process, in direct conflict with the long‐run absolute purchasing power parity hypothesis, which requires a stationary real exchange rate process. This conflict between market efficiency and long‐run PPP appears as something of a conundrum. We resolve this conundrum by relaxing the assumption of a constant real interest rate differential and analysing the vector equilibrium correction system linking prices and the exchange rate, and draw out the economic intuition of our result. Copyright © 2004 John Wiley & Sons, Ltd.
Bone regeneration in rabbit sinus lifting associated with bovine BMP
Authors: Allegrini Sergio , Yoshimoto Marcelo , Salles Marcos B. , König Bruno
Published: January 2004

Autogenous bone is considered the optimal grafting material for sinus lifting, although its harvesting causes great patient discomfort. Various approaches have been taken in order to obtain sinus lifting with preexisting tissue. However, because of the unsuitability of such tissue, additional materials have been required. Alternatively, biomaterials from humans or other animals are used. In this study, the efficacy of using morphogenetic bovine bone protein (BMPb) to augment the maxillary sinus floor was examined. Four grafting materials were employed: lyophilized bovine bone powder, absorbable collagen flakes, natural hydroxylapatite, and synthetic hydroxylapatite. Two groups of rabbits were studied. In one group, graft material only was used. In the other, graft material was combined with 0.5 mg BMPb. During 8 weeks of observation, polyfluorochrome tracers were injected in subcutaneous tissue to evaluate new bone‐ deposition periods. Following sacrifice, the samples were examined under fluorescent and light microscopes. Results indicated 33.34% more newly formed bone in BMPb animals than in controls. Graft‐material resorption increased, but natural HA showed no significant alterations. The results show that the use of BMPb, although providing osteoinduction, might not promote sufficient bone formation. Nonetheless, this material could provide an alternative to autogenous grafts, thereby avoiding patient discomfort. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 127–131, 2004
Segmented detachable structure of cochlear‐implant electrodes for close‐hugging engagement with the modiolus
Authors: Mirzadeh H. , Abbasi F.
Published: January 2004

Surface and bulk modification techniques of polydimethylsiloxane (PDMS) polymers were used to develop a new intracochlear electrode that can closely hug the inner wall of scala tympani. Laser‐induced surface grafting of poly (2‐hydroxyethyl methacrylate) (PHEMA) and sequential method for preparation of interpenetrating polymer networks (IPNs) of PDMS/PHEMA were, respectively, used for surface and bulk modifications. The hydrogel content and water‐uptake capability of the modified samples were optimized by Taguchi method for experimental design. The modified PDMS samples were examined by performing attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy, water contact‐angle measurement, and peel strength tests. The performances of actual‐sized fabricated electrodes were assessed inside a transparent model of scala tympani, which was filled with saline. After a swelling process, the hydrophilic branch begins to elongate and detach from hydrophobic branch and pushes it toward the inner wall. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 191–198, 2004
SEM/EDS evaluation of porcelain adherence to gold‐coated cast titanium
Authors: Lee K. M. , Cai Z. , Griggs J. A. , Guiatas L. , Lee D. J. , Okabe T.
Published: January 2004

The adhesion between titanium and dental porcelain is related to the diffusion of oxygen to the reaction layer formed on cast‐titanium surfaces during porcelain firing. The diffusion of oxygen could be suppressed by coating the titanium surface with a thin gold layer. This study characterized the effects of gold coating on titanium–ceramic adhesion. ASTM grade II CP titanium was cast into a MgO‐based investment (Selevest CB, Selec). The specimen surfaces were air abraded with 110‐μm Al2O3 particles. Gold coating was applied on titanium surfaces by three methods: gold‐paste (Deck Gold NF, Degussa‐Ney) coating and firing at 800 °C for three times, single gold‐paste coating and firing followed by sputter coating (40 mA, 500 s), and sputter coating (40 mA, 1000 s). Surfaces only air abraded with Al2O3 particles were used as controls. An ultra‐low‐fusing dental porcelain (Vita Titankeramik, Vident) was fused on titanium surfaces. Specimen surfaces were characterized by SEM/EDS and XRD. The titanium–ceramic adhesion was evaluated by a biaxial flexure test (N = 8), and area fraction of adherent porcelain (AFAP) was determined by EDS. Numerical results were statistically analyzed by one‐way ANOVA and the Student‐Newman‐Keuls test at α = 0.05. SEM fractography showed a substantial amount of porcelains remaining on the gold‐sputter‐coated titanium surfaces. A new Au2Ti phase was found on gold‐coated titanium surface after the firing. Significantly higher (p < .05) AFAP values were determined for the gold‐sputter‐coated specimens compared to the others. No significant differences were found among the other groups and the control. Results suggested that gold coatings used in this study are not effective barriers to completely protect titanium from oxidation during the porcelain firing, and porcelain adherence to cast titanium can be improved by gold‐sputter coating used in the present study. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 165–173, 2004
Effect of post‐processing heat treatment on the fracture strength of a heat‐pressed dental ceramic
Authors: Denry I. L. , Holloway J. A.
Published: January 2004

The purpose of this study was to evaluate the effect of post‐processing heat treatment on the fracture strength of a heat‐pressed lithium disilicate dental ceramic (OPC 3G). Bar‐shaped wax patterns (2 × 4 × 22 mm; n = 60) were invested and heat pressed in an automated pressing machine according to manufacturer's recommendations. The bars were polished to 1200 grit and annealed at 600 °C for 1 h. Two groups were left untreated as controls, one of which was Vickers indented in oil prior to testing in three‐point bending. Two groups were indented and then heat treated at either 800 or 825 °C for 30 min. The corresponding control groups were heat treated, then indented prior to testing. Optical micrographs of the indentations were taken before and after heat treatment under differential interference contrast. The fracture toughness and/or fracture strength of the specimens was determined by the indentation‐strength technique in three‐point bending. Indentation‐generated cracks were not discernible by optical microscopy after heat treatment at either 800 or 825 °C for 30 min, even under 1000 × magnification. ANOVA and Tukey's test showed that heat treatment in air at 825 °C for 30 min significantly increased the fracture strength of a heat‐pressable lithium disilicate ceramic. This result was attributed to healing of the flaws present in the material. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 174–179, 2004
Effects of the initial temperature of acrylic bone cement liquid monomer on the properties of the stem–cement interface and cement polymerization
Authors: Iesaka K. , Jaffe W. L. , Kummer F. J.
Published: January 2004

It has been shown that preheating the femoral stem prior to insertion minimizes interfacial porosity at the stem–cement interface. In this study, the effects of methylmethacrylate monomer temperature prior to mixing on the properties of stem–cement interface and cement polymerization were evaluated for 4 °C, room temperature, and 37 °C using a test model and cementing techniques that simulated a clinical situation. The nature and extent of interfacial porosity of stem–cement interface was quantified, the static shear strength of the stem–cement interface determined, and the time and temperature of polymerization at the cement–bone interface were measured. Compared to RT monomer, preheating monomer to 37 °C produced higher polymerization temperatures and greater initial interfacial shear strength with an unchanged amount of interfacial porosity. Precooling monomer to 4 °C produced lower polymerization temperatures and decreased initial interfacial shear strength, with the amount of interfacial porosity unchanged compared to the RT group. Although clinical techniques of preheating or precooling bone cement have some effects on the properties of the stem–cement interface and cement polymerization, they do not appear to enhance implant fixation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 186–190, 2004
Change of properties during storage of a UDMA/TEGDMA dental resin
Authors: Lee Jong Keun , Choi Joo‐Yeol , Lim Bum‐Soon , Lee Yong‐Keun , Sakaguchi Ronald L.
Published: January 2004

The aim of this study was to evaluate the changes in viscoelastic properties of a UDMA‐based dental resin as a function of time after initial light exposure. Specimens of a UDMA/TEGDMA (70:30 wt%) resin were irradiated by a visible‐light‐curing unit. Immediately after the irradiation, the light‐cured specimen was stored in the dark for different times from 1 to 120 h at 37 °C, and characterized by means of DMA, DSC, and FTIR spectroscopy. The irradiated specimen exhibited a bimodal shape in the form of two rapid declines in log E′ corresponding to glass transition with a plateau between the two declines. Two distinct peaks were seen in tan δ versus temperature. The thermal reaction of the incompletely cured sample with residual groups trapped by the fast reaction during irradiation is responsible for the plateau. After storage, significant changes were observed in dynamic mechanical parameters, DSC exotherm, and degree of conversion. Storage modulus continued to increase during the 4 h of storage and leveled off thereafter. Peak heights of tan δ versus temperature were also influenced by storage. Degree of conversion increased from 75 ± 2% immediately after irradiation to 87 ± 3% after 120 h storage. The changes of the properties of this dental resin system when stored at 37 °C after irradiation are clinically important in terms of stability, durability, and performance after initial polymerization. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 216–221, 2004
Some New uniform frames with block size four and index one or three
Authors: Ge Gennian , Lam C.W.H. , Ling Alan C.H.
Published: January 2004

In this paper, some new uniform frames with block size four and index one or three are obtained. The known existence results for (4,1)‐frames and (4,3)‐frames are both improved to the extent that only a finite number of possible exceptions remain. © 2003 Wiley Periodicals, Inc.
On optimal superimposed codes
Authors: Kim Hyun Kwang , Lebedev Vladimir
Published: January 2004

A (w,r) cover‐free family is a family of subsets of a finite set such that no intersection of w members of the family is covered by a union of r others. A binary (w,r) superimposed code is the incidence matrix of such a family. Such a family also arises in cryptography as a concept of key distribution patterns. In this paper, we develop a method of constructing superimposed codes and prove that some superimposed codes constructed in this way are optimal. © 2003 Wiley Periodicals, Inc. J Combin Designs 12: 79–71, 2004.
Some Hadamard matrices of order 32 and their binary codes
Authors: Araya Makoto , Harada Masaaki , Kharaghani Hadi
Published: January 2004

It is known that all doubly‐even self‐dual codes of lengths 8 or 16, and the extended Golay code, can be constructed from some binary Hadamard matrix of orders 8, 16, and 24, respectively. In this note, we demonstrate that every extremal doubly‐even self‐dual [32,16,8] code can be constructed from some binary Hadamard matrix of order 32. © 2004 Wiley Periodicals, Inc.
Some more 5‐GDDs and optimal (v), 5, 1)‐packings
Authors: Ge Gennian , Ling Alan C. H.
Published: January 2004

In this paper, we continue to investigate the existence of 5‐GDDs with types g5 m1 and gu. As an application, the known results on the existence of optimal packings with block size 5 are also improved. © 2003 Wiley Periodicals, Inc.
3‐Designs of PSL(2, 2n) With block sizes 4 and 5
Authors: Keranen M. S. , Kreher D. L.
Published: January 2004

We determine the distribution of 3‐designs among the orbits of 4‐ and 5‐element subsets under the action of PSL(2,2n) on the projective line. Thus we give complete information on all Kramer–Mesner matrices for the action of PSL(2,2n) on 3‐sets versus 4‐ and 5‐sets. As a consequence, all 3‐designs with block sizes 4 and 5 and automorphism group PSL(2,2n) can immediately be obtained. © 2003 Wiley Periodicals, Inc.
Hamilton cycle rich two‐factorizations of complete graphs
Authors: Bryant Darryn
Published: January 2004

For all integers n ≥ 5, it is shown that the graph obtained from the n‐cycle by joining vertices at distance 2 has a 2‐factorization is which one 2‐factor is a Hamilton cycle, and the other is isomorphic to any given 2‐regular graph of order n. This result is used to prove several results on 2‐factorizations of the complete graph Kn of order n. For example, it is shown that for all odd n ≥ 11, Kn has a 2‐factorization in which three of the 2‐factors are isomorphic to any three given 2‐regular graphs of order n, and the remaining 2‐factors are Hamilton cycles. For any two given 2‐regular graphs of even order n, the corresponding result is proved for the graph Kn ‐ I obtained from the complete graph by removing the edges of a 1‐factor. © 2004 Wiley Periodicals, Inc.
Even cycles in graphs
Authors: Conlon Joseph G.
Published: January 2004

Let G be a 3‐connected simple graph of minimum degree 4 on at least six vertices. The author proves the existence of an even cycle C in G such that G‐V(C) is connected and G‐E(C) is 2‐connected. The result is related to previous results of Jackson, and Thomassen and Toft. Thomassen and Toft proved that G contains an induced cycle C such that both G‐V(C) and G‐E(C) is 2‐connected. G does not in general contain an even cycle such that G‐V(C) is 2‐connected. © 2004 Wiley Periodicals, Inc. J Graph Theory 45: 163–223, 2004
Growth of Self‐Similar Graphs
Authors: Krön B.
Published: January 2004

Locally finite self‐similar graphs with bounded geometry and without bounded geometry as well as non‐locally finite self‐similar graphs are characterized by the structure of their cell graphs. Geometric properties concerning the volume growth and distances in cell graphs are discussed. The length scaling factor ν and the volume scaling factor μ can be defined similarly to the corresponding parameters of continuous self‐similar sets. There are different notions of growth dimensions of graphs. For a rather general class of self‐similar graphs, it is proved that all these dimensions coincide and that they can be calculated in the same way as the Hausdorff dimension of continuous self‐similar fractals: ${\rm dim}\ X={{\rm log}\ \mu \over {\rm log}\ \nu }$. © 2004 Wiley Periodicals, Inc. J Graph Theory 45: 224–239, 2004
Hepatitis B virus genotypes and spontaneous hepatitis B e antigen seroconversion in Taiwanese hepatitis B carriers
Authors: Kao Jia‐Horng , Chen Pei‐Jer , Lai Ming‐Yang , Chen Ding‐Shinn
Published: January 2004

Hepatitis B virus (HBV) is classified into eight genotypes (A–H), and genotype C is associated with more aggressive liver disease compared to genotype B. However, the mechanisms responsible for the clinical differences remain unclear. To test whether genotype C patients had with lower rates of spontaneous hepatitis B ge antigen (HBeAg) seroconversion than genotype B patients, stored serum samples from 146 Taiwanese adult HBeAg‐positive hepatitis B carriers followed‐up for a mean of 52 months (range, 12–120 months) were tested for HBV genotype by a molecular method. Genotype C patients were significantly older than genotype B patients (mean age, 37 ± 12 vs. 29 ± 10 years, P < 0.001). During the follow‐up period, genotype C patients had a significantly lower rate of spontaneous HBeAg seroconversion than genotype B patients (27 vs. 47%, P < 0.025). Spontaneous HBeAg seroconversion occurred one decade later in genotype C patients compared with genotype B patients. Multivariate analyses identified age ≤35 years (odds ratio: 2.08; 95% confidence interval [CI], 1.07–4.0; P < 0.05), high baseline serum alanine aminotransferase level (odds ratio: 2.34; 95%CI, 1.39–4.09; P < 0.005), and HBV genotype B (odds ratio: 1.94; 95%CI, 1.03–3.63; P < 0.05) as independent factors associated with spontaneous HBeAg seroconversion. In conclusion, genotype C patients, compared to genotype B patients, have a delayed HBeAg seroconversion in the immune clearance phase of chronic HBV infection, which may contribute to a more progressive liver disease and more refractory to antiviral therapy. J. Med. Virol. 72:363–369, 2004. © 2004 Wiley‐Liss, Inc.
HIV epidemic in central african republic: High prevalence rates in both rural and urban areas
Authors: Matsika‐Claquin Marcelle Diane , Massanga Marcel , Ménard Didier , Mazi‐Nzapako Jean , Ténegbia Jean‐Pierre , Mandeng Marie‐Joëlle , Willybiro‐Sacko Jean , Fontanet Arnaud , Talarmin Antoine
Published: January 2004

A sentinel serosurveillance study was conducted in Central African Republic to estimate the prevalence of HIV seropositivity in the general adult population in each province so that the public health authorities can target HIV prevention programmes to the priority areas. Blood samples were collected from women attending 48 antenatal clinics in urban and rural areas of the Central African Republic. These samples were tested for HIV antibodies in an anonymous and unlinked manner using strategy II recommended by WHO. The data were extrapolated to all women of reproductive age in Central African Republic by use of a parity‐based adjustment involving the application of correction factors to the observed prevalence rates. A total of 9,305 pregnant women were recruited from November 2001 to October 2002. HIV seroprevalence was high in all age groups (12% in the less than 20 year age group to 17% in the 25–29 year age group). The median prevalence of HIV in antenatal clinics was similar for rural areas, for Bangui and for other urban areas (16.5, 15.0, and 12.5% respectively). Adjustment for parity and fertility pattern increased the prevalence of HIV in all antenatal clinics except in Bangui. This first national study of HIV prevalence in Central African Republic revealed that the HIV epidemic is continuing to spread in both urban and rural areas. Thus, efforts to reduce transmission should be made in every part of the country. J. Med. Virol. 72:358–362, 2004. © 2004 Wiley‐Liss, Inc.
Characterization of mimotopes mimicking an immunodominant conformational epitope on the hepatitis C virus NS3 helicase
Authors: Jolivet‐Reynaud Colette , Adida Anne , Michel Sandrine , Deléage Gilbert , Paranhos‐Baccala Glaucia , Gonin Virginie , Battail‐Poirot Nicole , Lacoux Xavier , Rolland Dominique
Published: January 2004

The hepatitis C virus (HCV) nonstructural 3 (NS3) protein is composed of an amino terminal protease and a carboxyl terminal RNA helicase. NS3 contains major antigenic epitopes. The antibody response to NS3 appears early in the course of infection and is focused on the helicase region. However, this response cannot be defined by short synthetic peptides indicating the recognition of conformation‐dependent epitopes. In this study, we have screened a dodecapeptide library displayed on phage with anti‐NS3 mouse monoclonal antibodies (mAbs) that compete with each other and human anti‐HCV NS3 positive sera. Two peptides (mimotopes) were selected that appeared to mimic an immunodominant epitope since they were recognized specifically by the different anti‐NS3 mAbs of the study and by human sera from HCV infected patients. Homology search between the two mimotopes and the NS3 sequence showed that one of the two peptides shared amino acid similarities with NS3 at residues 1396–1398 on a very accessible loop as visualized on the three‐dimensional structure of the helicase domain whereas the other one had two amino acids similar to nearby residues 1376 and 1378. Reproduced as synthetic dodecapeptides, the two mimotopes were recognized specifically by 19 and 22, respectively, out of 49 sera from HCV infected patients. These mimotopes allowed also the detection of anti‐NS3 antibodies in sera of HCV patients at the seroconversion stage. These results suggest that the two NS3 mimotopes are potential tools for the diagnosis of HCV infection. J. Med. Virol. 72:385–395, 2004. © 2004 Wiley‐Liss, Inc.
Simultaneous detection and differentiation of human polyomaviruses JC and BK by a rapid and sensitive PCR‐ELAHA assay and a survey of the JCV subtypes within an Australian population
Authors: Whiley David M. , Arden Katherine E. , Mackay Ian M. , Syrmis Melanie W. , Sloots Theo P.
Published: January 2004

Human polyomaviruses JCV and BKV can cause several clinical manifestations in immunocompromised hosts, including progressive multifocal leukoencephalopathy (PML) and haemorrhagic cystitis. Molecular detection by polymerase chain reaction (PCR) is recognised as a sensitive and specific method for detecting human polyomaviruses in clinical samples. In this study, we developed a PCR assay using a single primer pair to amplify a segment of the VP1 gene of JCV and BKV. An enzyme linked amplicon hybridisation assay (ELAHA) using species‐specific biotinylated oligonucleotide probes was used to differentiate between JCV and BKV. This assay (VP1‐PCR‐ELAHA) was evaluated and compared to a PCR assay targeting the human polyomavirus T antigen gene (pol‐PCR). DNA sequencing was used to confirm the polyomavirus species identified by the VP1‐PCR‐ELAHA and to determine the subtype of each JCV isolate. A total of 297 urine specimens were tested and human polyomavirus was detected in 105 specimens (35.4%) by both PCR assays. The differentiation of JCV and BKV by the VP1‐PCR‐ELAHA showed good agreement with the results of DNA sequencing. Further, DNA sequencing of the JCV positive specimens showed the most prevalent JCV subtype in our cohort was 2a (27%) followed by 1b (20%), 1a (15%), 2c (14%), 4 (14%) and 2b (10%). The results of this study show that the VP1‐PCR‐ELAHA is a sensitive, specific and rapid method for detecting and differentiating human polyomaviruses JC and BK and is highly suitable for routine use in the clinical laboratory. J. Med. Virol. 72:467–472, 2004. © 2004 Wiley‐Liss, Inc.
Effects of potent antiretroviral therapy on the immune activation marker soluble CD27 in patients infected with HIV‐1 subtypes A–D
Authors: Atlas Ann , Thanh Ha Tran Thi , Lindström Anna , Nilsson Anna , Alaeus Annette , Chiodi Francesca , De Milito Angelo
Published: January 2004

HIV‐1 genetic subtypes might have a different impact on disease progression and response to antiretroviral therapy (ART). Few data are available on the immune activation profile in patients with different HIV‐1 subtypes. We have tested by ELISA the plasma levels of an immune activation marker, soluble CD27 (sCD27), in a cohort of 64 patients infected with HIV‐1 subtypes A–D, at baseline and after 1 year of virologically successful ART. Plasma sCD27 was significantly higher in the whole HIV‐1‐infected population as compared to healthy subjects [522 U/ml (188–1,307) vs. 285 U/ml (174–397), P < 0.001]. Among the four different HIV‐1 subtypes, patients with subtype C virus had significantly higher plasma sCD27 [684 U/ml, (188–1228)] as compared to patients with subtype A [428 U/ml (247–1307), P < 0.05] and B [454 (211–925), P < 0.05]. After 1 year of ART, plasma sCD27 significantly decreased in all groups but patients with subtype C viruses had the largest reduction of sCD27 from baseline. The data indicate that a similar immune activation profile is present in patients infected with HIV‐1 subtypes A, B, and D and that in presence of successful ART these subtypes respond similarly in terms of immune activation. Intriguingly, subtype C infection seems to be associated with higher levels of plasma sCD27, suggesting that HIV‐1 genetic subtype C may have a different impact on disease outcome and response to therapy. J. Med. Virol. 72:345–351, 2004. © 2004 Wiley‐Liss, Inc.
Elevation of soluble VCAM‐1 plasma levels in children with acute dengue virus infection of varying severity
Authors: Koraka Penelopie , Murgue Bernadette , Deparis Xavier , van Gorp Eric C.M. , Setiati Tatty E. , Osterhaus Albert D.M.E. , Groen Jan
Published: January 2004

Approximately 1,000 million infections with dengue viruses are estimated to occur annually. The majority of the cases develop mild disease, whereas only small proportion of the infected individuals develop severe hemorrhagic manifestations at the end of the acute phase of illness. In this study, the value of plasma levels of vascular cell adhesion molecule 1 (VCAM‐1) in the pathogenesis and prognosis of dengue illness was investigated in children with dengue infections of varying severity. The plasma levels of soluble VCAM‐1 (sVCAM‐1) were measured in serial plasma samples obtained from 168 children aged between 7 months and 14 years with confirmed dengue infection. Of those children, 71 were suffering from dengue fever, 30 were suffering from dengue hemorrhagic fever, and 67 were suffering from dengue shock syndrome. Plasma samples obtained from 21 patients with febrile illness other than dengue served as controls. A commercially available kit (R&D Systems, Oxon, UK) was used to measure the levels of sVCAM‐1 in plasma samples. sVCAM‐1 was elevated during acute dengue infection, and significantly elevated among dengue shock syndrome patients as compared to dengue fever or dengue hemorrhagic fever patients (P < 0.05). Statistical analysis revealed that sVCAM‐1 was associated with dengue disease severity and the time post infection (acute vs. convalescent phase) and not with age, sex, or previous exposure of the patients to dengue infection. A significant difference was found in the plasma levels of sVCAM‐1 between dengue shock syndrome and dengue fever patients, however, the prognostic value of this marker in the acute stage of dengue illness proved to be limited. These data also favor to study the further elucidation of the role of sVCAM‐1 in the pathogenesis of dengue infections. J. Med. Virol. 72:445–450, 2004. © 2004 Wiley‐Liss, Inc.
Increased detection of rotavirus using a real time reverse transcription‐polymerase chain reaction (RT‐PCR) assay in stool specimens from children with diarrhea
Authors: Pang Xiaoli L. , Lee Bonita , Boroumand Nasim , Leblanc Barbara , Preiksaitis Jutta K. , Yu Ip Charlotte C.
Published: January 2004

Six‐hundred and twenty‐six stool specimens collected from children with diarrhea over a 12‐month period were tested for rotavirus using a real time reverse transcription‐polymerase chain reaction (RT‐PCR) assay, a conventional nested PCR assay and by electron microscopy (EM). A fragment of 87 bp in a highly‐conserved region of non‐structural protein 3 (NSP3) in rotavirus genome was amplified by a single‐step RT‐PCR protocol in a closed‐tube system. Rotavirus was detected in 123 samples (20%) with the real time RT‐PCR assay, 113 samples (18%) with the nested‐PCR assay, and 79 samples (13%) with EM. Using serial diluted nucleic acid extract, we compared the sensitivity of real time RT‐PCR with conventional RT‐PCR and conventional nested PCR assays. Real time RT‐PCR was two to four logs more sensitive than the conventional assays. The reaction time required for the RT‐PCR assay is about half the time required for the conventional nested‐PCR. The real time RT‐PCR assay is both simple and rapid with advantages including enhanced sensitivity and a lower risk for cross‐contamination making it a useful tool for the detection of rotavirus in various situations including sporadic gastroenteritis, outbreaks, and environmental investigations. G1 was the predominant type (89%), followed by G2 (10%), and G4 (1%). No rotavirus of G3, G8, and G9 types were found. The peak season for rotavirus infection was January to May in northern Alberta. J. Med. Virol. 72:496–501, 2004. © 2004 Wiley‐Liss, Inc.
Different resistance mutations can be detected simultaneously in the blood and the lung of HIV‐1 infected individuals on antiretroviral therapy
Authors: White Natalie C. , Israel‐Biet Dominique , Coker Richard J. , Mitchell David M. , Weber Jonathan N. , Clarke John R.
Published: January 2004

In this retrospective study, matched peripheral blood and lung samples from patients on antiretroviral therapy were studied in order to investigate whether differences in mutations associated with resistance to nucleoside analogues could be detected between the lung and blood. Discordant mutation patterns in the reverse transcriptase (RT) between plasma and cell free bronchoalveolar lavage fluid (BAL‐fluid) HIV‐1 genomic RNA was observed in five out of seven patients on nucleoside reverse transcriptase inhibitor (NRTI) monotherapy and six out of seven on combination therapy. In the cellular compartments, DNA recovered from peripheral blood mononuclear cells (PBMCs) and cells from BAL‐cells discordant HIV‐1 resistance genotypes were detected in 15 out of 44 matched samples. Differences in resistant genotypes between PBMCs and BAL‐cells were most pronounced in patients receiving combination antiretroviral therapy. The pattern and number of mutations in RT associated with resistance differed in the BAL‐cells compared to PBMCs in four out of 12 subjects not receiving antiretroviral therapy at the time of bronchoscopy, three from 14 patients on NRTI monotherapy, five out of nine on dual combination therapy and three out of nine on HAART. The differences in the detection of resistance mutations between blood and the lung suggest that the lung is a site of replication for HIV‐1. J. Med. Virol. 72:352–357, 2004. © 2004 Wiley‐Liss, Inc.
Human herpesvirus‐8 infection in pregnancy and labor: Lack of evidence of vertical transmission
Authors: Sarmati Loredana , Carlo Ticconi , Rossella Santangelo , Montano Marco , Adalgisa Pietropolli , Rezza Giovanni , Andreoni Massimo
Published: January 2004

To investigate whether vertical transmission of the human herpesvirus 8 (HHV‐8) may occur during pregnancy or at delivery, we enrolled 295 women recruited attending the Division of Obstetrics and Gynecology of a University Teaching of Rome Tor Vergata, S. Eugenio Hospital. The study population was divided in two groups: 245 pregnant women who underwent amniocentesis for genetic screening at 16–18 weeks gestation (group 1) and 50 women at the childbirth (group 2). Maternal blood was obtained from all women. Amniotic fluid (group 1) and cord blood (group 2) were obtained at midtrimester and at delivery, respectively. The presence of anti‐HHV‐8 antibodies in serum samples was investigated by an immunfluorescence assay. All amniotic fluids, maternal blood, and cord blood samples from HHV‐8 seropositive women were tested for the presence of HHV‐8 DNA sequences by the polymerase chain reaction. Thirty women, 27 of the group 1 and three of the group 2, were found to have anti‐HHV‐8 antibodies. Two neonates of the three seropositive mothers of the group 2 had anti‐HHV‐8 antibodies in cord blood. HHV‐8 DNA sequences were detected in the blood of one woman of the group 2. None of the amniotic fluid and cord blood samples had detectable HHV‐8 DNA sequences. This study suggests that vertical transmission of HHV‐8 is unlikely or, at least, very rare. J. Med. Virol. 72:462–466, 2004. © 2004 Wiley‐Liss, Inc.
Detection and genotyping of TT virus in healthy and subjects with HBV or HCV in different populations in the United Arab Emirates
Authors: Al‐Moslih Moslih I. , Abuodeh Raed O. , Hu Yu‐Wen
Published: January 2004

TT virus (TTV) and TTV‐like viruses (TTVLs) have been reported to be associated with non‐A–E hepatitis. To determine the rate of infection and genotypic characteristics of TTV in the United Arab Emirates (UAE), a total of 449 serum samples representing different populations in the UAE and comprising healthy as well as patients positive for HBsAg and HCV were screened. National subjects (n = 200) and non‐nationals residing in the UAE (n = 249) were tested by PCR. The results obtained showed that the rate of TTV infection in healthy nationals, and those with HBsAg or antibody to HCV were 34.9, 97.9, and 95.7, respectively, compared to 89.1% (115/129), 89.2% (66/74), and 84.8% (39/46), respectively, in non‐nationals. Sequence analysis of the untranslated region (UTR) using 71 clones generated from the PCR products of eight serum samples from healthy individuals (four nationals and four non‐nationals) showed that 83.1% of the TTV clones were classified into groups 1–4, whereas 16.9% into possibly new genotype(s). The analysis also revealed that healthy national subjects carried multiple viruses. Phylogenetic analysis of representative sequences revealed clustering of clones into at least five major groups. Also, when compared to reference genotypes (from GenBank), two of our clones belonged to two previously identified genotypes. Non‐significant gender differences were seen in all ethnic groups studied (P > 0.05). In conclusion, the rate of TTV infection in the UAE nationals is significantly lower (P < 0.05) than that of the non‐nationals and several genotypes were isolated with common multi‐infections. J. Med. Virol. 72: 502–508, 2004. © 2004 Wiley‐Liss, Inc.
Measurement of antirotavirus IgM/IgA/IgG responses in the serum samples of Indian children following rotavirus diarrhoea and their mothers
Authors: Ray Pratibha G. , Kelkar Shobhana D.
Published: January 2004

Rotavirus specific, serum IgM/IgA/IgG levels among hospitalized children and their respective mothers were determined. Children were grouped as having rotavirus diarrhoea (RVD) and non‐rotavirus diarrhoea (NRVD) on the basis of fecal excretion measured by ELISA and RT‐PCR. Although IgM seropositivity was observed among children of both the groups, it was significantly higher in the acute as well as convalescent phase serum samples (P < 0.05 for both) of RVD group. Five out of ten acute sera from the NRVD group were positive for IgM and seven showed IgA/IgG seroconversion indicating rotavirus infection among these children in the past. It was noted that, three out of 24 mothers' sera from RVD group, showed presence of IgM in the serum collected during convalescence of their children. The observation suggests, subclinical rotavirus infection among mothers probably contacted from their children. This is supported by the seroconversion for IgA/IgG among these three mothers. Such a phenomenon was not noticed among the mothers from NRVD group. In general, IgA positivity did not vary significantly among the children from both the groups. IgA seropositivity was significantly higher (P < 0.001) from children of RVD group as compared to healthy group of children following rotavirus infection. From RVD group, all the child patients and 12 mothers out of 24 (50%) showed IgA/IgG seroconversion. None of the mothers from NRVD group showed seroconversion. Serum samples of healthy children and adults, showed IgM positivity at equal level (10%), but a significant difference (P < 0.01) was observed in IgA positivity. In conclusion, subclinical transmission of rotavirus infection from children to their mothers may occur. Seroconversion alone cannot be considered as a marker of rotavirus diarrhoea in children. Moreover, about 40–50% of subjects lacked rotavirus specific IgA at protective levels, making them susceptible to rotavirus infection. J. Med. Virol. 72:416–423, 2004. © 2004 Wiley‐Liss, Inc.
Lack of clinical significance of variability in the internal ribosome entry site of hepatitis C virus
Authors: Thelu Marie‐Ange , Drouet Emmanuel , Hilleret Marie‐Noëlle , Zarski Jean‐Pierre
Published: January 2004

The extreme 5′‐proximal sequence of the hepatitis C virus (HCV) genome including the 5′ non‐coding region (5′NCR) of 341 nucleotide long and the first 30 nucleotides of the core region is highly conserved among different HCV genotypes. It contains a segment termed Internal Ribosome Entry Site (IRES) that regulates the cap‐independent translation of HCV‐RNA to polyprotein. Sequence variability in this region has important implications for structural organisation and function of the IRES element and could correlate with HCV RNA concentration or response to antiviral therapy. Fourteen patients (seven women, seven men) with chronic hepatitis C were separated into two groups according to their response to antiviral therapy. Seven of these were sustained responders to treatment by Interferon alpha 2b and Ribavirin and seven were non‐responders. After cloning‐sequencing, the IRES (nt 21 to 374) appears to be structurally highly conserved. However some variability was found between the different isolates obtained: 209 substitutions with a median of four variants/patients. Comparison of the number of variants present in the viral population of the sustained responders and non‐responders patients do not show any difference. Positioning of the mutations on the predicted IRES secondary structure showed that the distribution of the mutations and their apparition frequency were different between the two groups. The translation initiator AUG‐4 codon, located in the stem‐loop IV, is never modified. Variations observed in the IRES are not a parameter of response to antiviral therapy, but the integrity of this region is a necessary condition to maintain its activity. J. Med. Virol. 72:396–405, 2004. © 2004 Wiley‐Liss, Inc.
An anticopper antiangiogenic approach for advanced cancer in spontaneously occurring tumors using tetrathiomolybdate: A pilot study in a canine animal model
Authors: Kent Michael S. , Madewell Bruce R. , Dank Gillian , Dick Robert , Merajver Sofia D. , Brewer George J.
Published: January 2004

In this pilot study, 13 dogs of various breeds and ages with a variety of advanced tumors were treated with the antiangiogenic copper complexing drug tetrathiomolybdate. Dose escalations were performed to determine the safe and effective dose in dogs. The study was designed to last for a 6‐month period for each dog entered. Dogs were examined weekly for the first 3 months and then every other week for the next 3 months. Complete blood count, serum biochemistry panel, and measurement of serum ceruloplasmin (Cp) content were conducted at each visit to monitor response to drug administration. Serum Cp was used as a surrogate marker of copper status. The owner reported toxicity at each visit. The dog was examined for physical abnormalities. Tumor measurements were completed every 2 weeks using direct measurements of the tumor with calipers in three planes or by direct measurements of the tumor using radiographic or ultrasonographic images in two planes. Tumor response was evaluated only after dogs achieved a 4‐week reduction in their serum Cp content. Tumor responses were defined as either disease stabilization or reduction in tumor volume. Nine dogs achieved Cp reduction. Of those dogs, five had no response to treatment, whereas four dogs had tumor responses after Cp reduction, characterized as either disease stabilization or reduction in tumor volume, for the remainder of the study period. There was only mild self‐limiting toxicity with use of the drug. J. Trace Elem. Exp. Med. 17:9–20, 2004. © 2004 Wiley‐Liss, Inc.