bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anti‐proliferative effects of 8‐chloro‐cAMP and other cAMP analogs are unrelated to their effects on protein kinase A regulatory subunit expression
Authors: Lamb Darija , Steinberg Robert A. 
Published: October 2002

AbstractConflicting reports have attributed 8‐chloro‐cAMP (Cl‐cAMP)‐mediated inhibition of tumor cell growth to either a toxic 8‐chloro‐adenosine (Cl‐AdR) breakdown product or a Cl‐cAMP‐mediated decrease in ratio of Type I to Type II regulatory (R) subunits of protein kinase A (PKA). Using the MCF‐7 human breast cancer and S49 mouse lymphoma cell lines as models, we show that the effects of Cl‐cAMP and other cAMP analogs on growth and R subunit expression are unrelated. MCF‐7 cell growth was insensitive to most analogs and inducers of cAMP, but was potently inhibited by Cl‐cAMP acting through uptake and phosphorylation of its Cl‐AdR breakdown product. Possible roles of adenosine receptors or P2 purinoceptors in these Cl‐cAMP‐mediated growth effects were ruled out by studies with agonists and antagonists. Cholera toxin markedly decreased the ratio of Type I to Type II R subunits in MCF‐7 cells without affecting growth, while growth inhibitory concentrations of Cl‐cAMP or Cl‐AdR had insignificant effects on this ratio. In S49 cells, where PKA activation is known to inhibit cell growth, PKA‐deficient mutants retained sensitivity to both Cl‐cAMP and the related 8‐bromo‐cAMP. Adenosine kinase (AK)‐deficient S49 cells were inhibited only by higher concentrations of these 8‐halogenated cAMP analogs. Of the commonly used cAMP analogs, only 8‐(4‐chlorophenylthio)‐cAMP acted purely as a cyclic nucleotide—having no effect on PKA‐deficient cells, but strongly inhibiting both wild‐type and AK‐deficient cells. Where growth inhibitory concentrations of most cAMP analogs reduced RI expression in the AK‐deficient mutant, a functionally equivalent concentration of (N6, O2′)dibutyryl‐cAMP maintained or increased this expression. © 2002 Wiley‐Liss, Inc.
Oxidative stress in phagocytes—“The enemy within”
Authors: Splettstoesser Wolf D. , Schuff‐Werner Peter 
Published: October 2002

AbstractPhagocytes represent a powerful defense system against invading microorganisms that threaten the life or functional integrity of the host. The capacity to generate and release substantial amounts of reactive oxygen species is a unique property of activated polymorphonuclear and mononuclear phagocytes. The crucial role of these molecules in killing microorganisms and their consecutive contribution to tissue damage during injury and inflammation is widely known. Although much research has been done to explore the molecular events involved in the interaction of oxygen intermediates with microbes or host tissue, surprisingly little attention has been paid to the effect of reactive metabolites on the phagocyte itself. This fact is especially surprising, since it is apparent that the activated phagocyte is directly exposed to its own toxic metabolites. The potential damage occurring during excessive radical formation might notably alter the vital functions of these primarily immunocompetent cells. Moreover, the critical role of oxygen radicals in apoptosis of leukocytes has been recently revealed. Apoptosis is now supposed to represent a key mechanism in neutrophil deactivation and resolution of inflammation. Therefore, this review will focus on the delicate balance between released oxidants and antioxidative protection within the phagocytes themselves. General and phagocyte‐specific antioxidative mechanisms, which have co‐evolved with the radical generating machinery of phagocytes, are discussed, since the outcome of local inflammation can directly depend on this antioxidative capacity and might range from adequate elimination of the pathogen with minimal acute tissue damage to progression towards a systemic inflammatory response syndrome. Microsc. Res. Tech. 57:441–455, 2002. © 2002 Wiley‐Liss, Inc.
How local irregularity gets global in a graph
Authors: Rautenbach Dieter , Volkmann Lutz 
Published: October 2002

AbstractWe prove asymptotically tight bounds on the difference between the maximum degree and the minimum degree of a simple graph in terms of its order and of the maximum difference between the degrees of adjacent vertices. Examples showing tightness and a conjecture are presented. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 18–23, 2002
Synthesis of tritium labeled isotopomers of L‐tyrosine
Authors: Augustyniak W. , Suchecki P. , Jemielity J. , Kański R. , Kańska M. 
Published: October 2002

AbstractThe synthesis of four selectively labeled isotopomers of L‐tyrosine, (L‐Tyr), using chemical and enzymatic methods is reported. Four tritium labeled isotopomers of L‐phenylalanine (L‐Phe) – [2‐3H]‐, [2′,6′‐3H2]‐, [3R‐3H]‐ and [3S‐3H]‐ have been synthesized using a combination of chemical and enzymatic methods. The labeled isotopomers of L‐Phe have been converted into [2 ‐3H]‐, [2′,6′‐3H2]‐, [3R‐3H]‐, and [3S‐3H]‐L‐Tyr by using the enzyme L‐phenyl‐alanine 4′‐monooxygenase. Copyright © 2002 John Wiley & Sons, Ltd.
Comparative studies of the development and differentiation of chloride cells in tilapine fish with different reproductive styles
Authors: Fishelson Lev , Bresler Vladimir 
Published: October 2002

AbstractUsing light and electron microscopy and fluorescent probes, we followed the ontogenesis of selected organs in embryos of several species of tilapia (Cichlidae, Pisces) with emphasis on chloride cell differentiation in species with two different reproductive styles: we compared the substrate‐brooder Tilapia zillii and the mouth‐brooders Oreochromis niloticus, O. aureus, Sarotherodon galilaeus, and Tristramella sacra. In all species a transitory blood network system nurtured by the vena caudalis inferiores supplied the yolk sac and preanal finfold during the advanced stages of embryonic and initial stages of larval development. During these stages chloride cells occurred on the yolk sac, as a part of the abdominal epithelium. The cells and their associated blood plexus remained active here until the gill‐lamellae, operculum, and mouth became functional. The chloride cells of their epithelium and blood system then took over, concomitant with a gradual degradation of the transitory blood system on the yolk sac. Ontogenesis of these systems (transitory and permanent) progressed at a higher rate in substrate‐brooders than in mouth‐brooders and was correlated with the earlier functioning of the gill‐operculum system. Thus, at a constant temperature of 26°C, the more exposed T. zillii progeny completed metamorphosis at 7–8 days after fertilization, calculated around 5,000 ± 80 h/temp, whereas juveniles of more protected mouth‐brooders attained a similar stage only 15 ± 1 days after fertilization and around 9,000 ± 200 h/temp. This earlier development of chloride cells and other pivotal organs in environmentally exposed progeny of substrate‐brooders, as compared to the protected progeny of mouth‐brooders, shows that their ontogeny was selected for the optimal survival style under specific etho‐ecological conditions. J. Morphol. 253:118–131, 2002. © 2002 Wiley‐Liss, Inc.
Ephemeroptera egg chorion characters: A test of their importance in assessing phylogenetic relationships
Authors: Domínguez Eduardo , Gabriela Cuezzo María 
Published: October 2002

AbstractThe egg chorion ultrastructures of the Hermanella–Traverella (Insecta: Ephemeroptera) species complex were studied from a comparative point of view and used for the first time in a cladistic analysis. Egg characters, along with other nymphal and adult morphological characters, were used to assess the phylogenetic relationships of the species complex. In order to test the value of egg characters, analyses were performed on three matrices: 1) egg characters alone, 2) adult and nymphal characters, and 3) adult, nymphal, and egg characters. The computer program Pee‐Wee was used to carry out the analysis. The cladistic analysis confirmed the value and potential of egg chorionic characters in assessing the phylogenetic relationships among ephemeropteran species. Egg characters, when added to the nymphal and adult character matrix, provided extra support to the monophyletic nature of the Hermanella–Traverella complex. Previously weakly defined clades were also resolved based on the new evidence. In the species studied the egg chorionic structures as well as their shape did not change after oviposition or water immersion, remaining constant through the different maturation stages of each species (mature nymph, subimago, and imago). For this reason, the eggs are a valuable source of information to unambiguously identify and associate a nymph to its correspondent adult stage when rearing is not possible. J. Morphol. 253:148–165, 2002. © 2002 Wiley‐Liss, Inc.
Serous cutaneous glands in new world hylid frogs: An ultrastructural study on skin poisons confirms phylogenetic relationships between Osteopilus septentrionalis and Phrynohyas venulosa
Authors: Delfino Giovanni , Brizzi Rossana , Nosi Daniele , Terreni Alessandro 
Published: October 2002

AbstractTransmission electron microscope investigations of the serous (poison) skin glands in the New World tree frogs Osteopilus septentrionalis and Phrynohyas venulosa revealed that they produce granules with closely similar substructures, namely, a dense cortex and pale medulla. In both species these features, that contrast the complex, sometimes repeating patterns described in other hylid frogs, derive from similar secretory and maturational processes starting from the Golgi phase of poison biosynthesis. Observations on secretory discharge showed that the two species share common release mechanisms, based on bulk discharge (holocrine) processes. Our data provide novel evidence of the extensive ultrastructural polymorphism of serous skin products in Hylidae and agree with phylogenies that regard this family as polyphyletic in origin. Assuming that ultrastructural features of cutaneous poison biosynthesis and maturation are adequate clues for tracking anuran phylogeny, the present findings also support a close relationship between Osteopilus and Phrynohyas taxa as previously suggested by osteological evidence. J. Morphol. 253:176–186, 2002. © 2002 Wiley‐Liss, Inc.
In vitro susceptibility to infection with SIVcpz and HIV‐1 is lower in chimpanzee than in human peripheral blood mononuclear cells*
Authors: Ondoa Pascale , Davis David , Kestens Luc , Vereecken Chris , Ribas Sergio Garcìa , Fransen Katrien , Heeney Jonathan , van der Groen Guido 
Published: October 2002

AbstractThis study was undertaken to evaluate and compare the susceptibility of chimpanzee versus human peripheral blood mononuclear cells (PBMCs) to infection with SIVcpz and HIV‐1 non‐syncitium inducing primary isolates. The results demonstrate clearly that chimpanzee PBMCs have a lower capacity to support viral replication as compared to human PBMCs. There was no experimental evidence that this difference was due to a lower availability of target cells for viral infection (PBMCs positive for CD4 and CCR5 molecules) or to a differential susceptibility to apoptosis (PBMCs positive for CD4 and CD95 molecules). A lower capacity of chimpanzee PBMCs to support SIVcpz and HIV‐1 replication in vitro is related to a post‐entry barrier to virus replication. J. Med Virol. 67:301–311, 2002. © 2002 Wiley‐Liss, Inc.
Detection of parvovirus B19 NS1‐specific antibodies by ELISA and western blotting employing recombinant NS1 protein as antigen
Authors: Heegaard Erik D. , Rasksen Cecilie J. , Christensen Jesper 
Published: October 2002

AbstractHuman parvovirus B19 (B19) encodes a number of nonstructural proteins, including the major protein, NS1, and two structural proteins, VP1 and VP2. The use of denatured NS1 in enzyme‐linked immunosorbent assay (ELISA) and Western blot (WB) assay has provided an opportunity to study some of the immunologic properties of NS1, but the results have been equivocal and the diagnostic sensitivity poor, probably because of the absence of conformational epitopes. Various viral isolates and baculovirus vectors were employed to produce recombinant B19 NS1 under nondenaturing conditions for the first time. To assess the antigenicity of purified B19 NS1, the reaction patterns of 252 samples were compared by B19 NS1 and VP2 ELISA. In sera from individuals with past infection (VP2 IgG‐positive), the use of this new antigen increased significantly the sensitivity of ELISA compared with WB (78% vs. 33%, P = 0.001), contradicting perpetuated claims that B19 NS1 IgG is detected primarily in patients with arthralgia or chronic infection. Previous reports of the absence of NS1 IgG during the initial phase of infection (< 6 weeks) were proved incorrect by the detection of NS1 IgG in 60% of samples from patients recently infected by B19. Including conformational epitopes in the ELISA increases the diagnostic sensitivity, although immunologically, a temporal (years) attenuation of NS1 antibodies appears to take place. This novel diagnostic tool may be useful as a supplement in case of borderline results by VP2 ELISA and for monitoring the efficacy of future capsid‐based B19 vaccines. J. Med Virol. 67:375–383, 2002. © 2002 Wiley‐Liss, Inc.
Strong interaction between human herpesvirus 6 and peripheral blood monocytes/macrophages during acute infection
Authors: Kondo Kazuhiro , Kondo Toshio , Shimada Kazuya , Amo Kiyoko , Miyagawa Hiromi , Yamanishi Koichi 
Published: October 2002

AbstractHuman herpesvirus 6 (HHV‐6) encodes a viral chemokine and chemokine receptors that may modify the functions of monocytes/macrophages (MO/Mϕ) during productive HHV‐6 infection. The interactions between HHV‐6 and MO/Mϕ during acute infection, however, remain poorly understood. In this study, we investigated the tropism of HHV‐6 in peripheral blood mononuclear cells (PBMCs) during acute infection. We detected 637 ± 273 copies of viral DNA in 104 MO/Mϕ. in contrast, in 104 CD4+ T cells, which have been reported to be viral carriers during the acute infection of HHV‐6, we found only 115 ± 42 copies of viral DNA. Consistent with these data, virus was isolated from MO/Mϕ an order of magnitude more frequently than from CD4+ T cells. Viral mRNA U79/80, which indicates viral replication, was detectable in the MO/Mϕ. In addition, the mRNAs that encode viral chemokine receptors U12 and U51, which may modify the function of MO/Mϕ, were expressed in the cells. Therefore, productively infected MO/Mϕ may be the dominant cell population that is responsible for HHV‐6 viremia during acute HHV‐6 infection. The strong interaction of HHV‐6 with MO/Mϕ may be partly responsible for the pathogenesis of this virus. J. Med Virol. 67:364–369, 2002. © 2002 Wiley‐Liss, Inc.
Prevention and control of hepatitis B in China
Authors: Sun Zongtang , Ming Lihua , Zhu Xu , Lu Jianhua 
Published: October 2002

AbstractAbout 170 million Chinese are infected chronically with HBV and 10% suffer from chronic hepatitis. Around half a million Chinese die from hepatitis B caused hepatocellular carcinoma and endstage cirrhosis each year. From 1983 to the present, a controlled clinical trial involving 80,000 children on a universal hepatitis B vaccination programme to prevent chronic hepatitis, hepatocellular carcinoma, and endstage cirrhosis was implemented in Qidong, China. A pilot study demonstrated that the HBsAg rate reached the adult level before the fifth year of age, and neonatal vaccination with either plasma‐derived or recombinant hepatitis B vaccines provided a similar 75% protective efficacy against HBV infection. The high rate of follow‐up and blood tests coverage of the cohorts provided data to show 75% protection at the tenth to eleventh years of age against serum HBsAg and also against prolonged hepatic dysfunction. The strategy of controlling hepatitis B nationwide was based on the universal immunisation of newborns, beginning in cities and then the rural areas. The large‐scale vaccine source was provided by domestic plants through technology transfer, first providing plasma‐derived vaccine replaced completely by recombinant DNA vaccine in 1997. An official survey in 1999 using a cluster sampling of 25,878 children from 31 provinces reported an average coverage rate of three dose of hepatitis B vaccination of 70.7%, being higher in urban areas. The Ministry of Public Health of China has planned to integrate hepatitis B vaccination into the nationwide EPI program with Government‐provided vaccines starting January 1, 2002. J. Med. Virol. 67:447–450, 2002. © 2002 Wiley‐Liss, Inc.
Immunoglobulin G antibody avidity assay for serodiagnosis of hepatitis C virus infection
Authors: Kanno Atsushi , Kazuyama Yukumasa 
Published: October 2002

AbstractIt has been reported that the avidity of specific IgG antibody is lower in primary viral infection than in chronic viral infection. However, few studies have been reported on the IgG avidity in hepatitis C virus (HCV) infection. In the present study, 36 patients with antibody to HCV (anti‐HCV) were examined for IgG avidity by an enzyme immunoassay with or without urea elution. The avidity index was significantly low in patients with primary HCV infection (7.7 ± 6.8%, mean ± SD), compared with patients with chronic HCV infection (77.0 ± 21.8%) and individuals with past HCV infection (44.5 ± 12.6%). Temporal changes of IgG avidity were examined in six patients with primary HCV infection. The avidity index was low in the acute phase of the infection and then increased with time. These results suggest that the avidity assay for IgG anti‐HCV is a useful method for distinguishing primary HCV infection from chronic or past HCV infection. J. Med. Virol. 68:229–233, 2002. © 2002 Wiley‐Liss, Inc.
Variation of hepatitis C virus load, hypervariable region 1 quasispecies and CD81 hepatocyte expression in hepatocellular carcinoma and adjacent non‐cancerous liver
Authors: Young Kung‐Chia , Lin Pin‐Wen , Hsiao Wei‐Chiang , Chang Ting‐Tsung , Chang Yu‐Chung , Wu Hwa‐Lin 
Published: October 2002

AbstractHepatitis C virus (HCV) infection is etiologically associated with the development of hepatocellular carcinoma (HCC) worldwide. HCV has been reported to exist and replicate in both HCC and adjacent non‐cancerous liver tissue, but limited information was available on HCV viral load and quasispecies composition in HCC relative to adjacent non‐cancerous hepatocytes. Previous study has also suggested CD81, a surface hepatocyte protein, as a receptor for HCV. To clarify the above, HCV‐RNA and CD81‐RNA titers in 20 paired hepatectomized liver and serum were quantitatively measured by chemiluminescent RT‐cPCR. Hypervariable region 1 (HVR‐1) variations of parallel specimens were analyzed after subcloning in 6 patients. HCV‐RNA levels in serum and non‐cancerous liver were markedly higher for HCV genotype 1 than genotype non‐1. HCV levels were markedly higher in non‐cancerous liver than in HCC (P = 0.001) in a genotype‐independent manner, with a mean ratio of 56:1 for non‐cancerous tissue to HCC. Both non‐cancerous and HCC tissues had the same level of CD81‐RNA expression, which was not linked to HCV load. HCV‐RNA quantity in both HCC and non‐cancerous liver correlated with the number of HVR‐1 quasispecies in the tissue, and distinct HVR‐1 subclones existed. J. Med. Virol. 68:188–196, 2002. © 2002 Wiley‐Liss, Inc.
Replication of enhancer‐deficient amphotropic murine leukemia virus in human fibrosarcoma but not in primary human fibroblasts
Authors: Reuss Frank U. , Berdel Bianca , Heber Ricarda , Bantel‐Schaal Ursula 
Published: October 2002

AbstractAmphotropic murine leukemia virus (MLV) replicates in cells from various mammalian species including humans and is a potential contaminant in MLV vector preparations for human gene transfer studies. In general, MLV replication depends on the expression of viral genes under the control of 75 bp enhancer elements in the long terminal repeat. However, in specific human fibrosarcoma and lymphoma lines replication of amphotropic MLV is possible without these enhancers. Fibrosarcomas are malignant tumors of fibroblast origin. To test the replication potential of intact and enhancerless amphotropic MLV in untransformed cells, infection studies with these viruses were carried out in three types of primary human fibroblasts. Replication of amphotropic MLV is observed in two of three tested fibroblast strains. None of these primary human fibroblasts is permissive for enhancer‐deficient MLV, suggesting that replication of this virus may be limited to transformed cells. J. Med. Virol. 68: 278–284, 2002. © 2002 Wiley‐Liss, Inc.
Transition probability coefficients and the stability of finite difference schemes for the diffusion and Telegraphers' equations
Authors: Malachowski Michal J. 
Published: October 2002

AbstractA probabilistic approach has been used to analyse the stability of the various finite difference formulations for propagation of signals on a lossy transmission line. If the sign of certain transition probabilities is negative, then the algorithm is found to be unstable. We extend the concept to consider the effects of space and time discretizations on the signs of the coefficients in a probabilistic finite difference implementation of the Telegraphers' equation and draw parallels with the transmission line matrix (TLM) technique. Copyright © 2002 John Wiley & Sons, Ltd.
TLM for diffusion: consistent first time step. Two‐dimensional case
Authors: Enders Peter , H. Pulko Susan , Stubbs David M. 
Published: October 2002

AbstractIn initializing a transmission line matrix (TLM) diffusion model it is necessary to consider both initial concentration (temperature) and initial flow. As usual, only one of them is given; an auxiliary formula is necessary to calculate the distribution for the first time step. It has been shown that the standard formula may introduce additional numerical errors (International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 1993; 6:135; International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 1993; 6:161) and that these errors can persist over many time steps. In this paper, we show how an initial modification to the normal TLM algorithm can remove such errors, and we demonstrate the method by applying it to a two‐dimensional TLM heat diffusion model for a copper plate. Copyright © 2002 John Wiley & Sons, Ltd.
TLM model of waves in moving media
Authors: O'Connor William J. 
Published: October 2002

AbstractWaves in moving media arise in fluid mechanics and elastic mechanics and are especially significant in acoustics. They are characterized by direction‐dependent wave speeds. When compared with the wave equation, the governing differential equation, ytt+αyxt+βyxx=0 has an extra, cross derivative term. An original solution method based on transmission line matrix (TLM) modelling is presented. By means of supplementary link lines controlled by notional ‘diodes’ the TLM mesh wave propagation characteristics are directionally biased. The algorithm is derived and performance assessed for the one‐dimensional case. Numerical results agree closely with analytical solutions. The algorithm has interesting properties promising new application areas for TLM. Copyright © 2002 John Wiley & Sons, Ltd.
TLM‐based solutions of the Klein–Gordon equation (Part II)
Authors: O'Connor William J. , Clune Fergus J. 
Published: October 2002

AbstractIn Part I, two TLM‐based solutions were presented for the Klein–Gordon Equation in its basic form, with the TLM pulses representing the primary variable. In Part II, two further approaches are presented in which the TLM pulses now represent derivatives of the primary variable, with respect to either space or time. As in Part I, the two solution schemes were verified symbolically and numerically. They illustrate further ways to extend the power of TLM beyond its traditional application areas. Some of these areas are discussed briefly. Copyright © 2002 John Wiley & Sons, Ltd.