bluuebunny/crossref_metadata_2025 huggingface dataset:
Photosynthetic and Other Phosphoenolpyruvate Carboxylase Isoforms in the Single-Cell, Facultative C4System of Hydrilla verticillata
Authors: Rao Srinath K. , Magnin Noël C. , Reiskind Julia B. , Bowes George
Published: October 2002

The submersed monocot Hydrilla verticillata (L.f.) Royle is a facultative C4 plant. It typically exhibits C3 photosynthetic characteristics, but exposure to low [CO2] induces a C4 system in which the C4 and Calvin cycles co-exist in the same cell and the initial fixation in the light is catalyzed by phosphoenolpyruvate carboxylase (PEPC). Three full-length cDNAs encoding PEPC were isolated from H. verticillata, two from leaves and one from root. The sequences were 95% to 99% identical and shared a 75% to 85% similarity with other plant PEPCs. Transcript studies revealed that one isoform,Hvpepc4, was exclusively expressed in leaves during C4 induction. This and enzyme kinetic data were consistent with it being the C4 photosynthesis isoform. However, the C4 signature serine of terrestrial plant C4isoforms was absent in this and the other H. verticillata sequences. Instead, alanine, typical of C3 sequences, was present. Western analyses of C3 and C4 leaf extracts after anion-exchange chromatography showed similar dominant PEPC-specific bands at 110 kD. In phylogenetic analyses, the sequences grouped with C3, non-graminaceous C4, and Crassulacean acid metabolism PEPCs but not with the graminaceous C4, and formed a clade with a gymnosperm, which is consistent with H. verticillataPEPC predating that of other C4 angiosperms.
There’s no business like e‐business
Authors: Palmer Roger
Published: October 2002

Seeks to address directly two assumptions that are inherent in current discussions concerning business and the role of technology. First, that business intelligence is, in fact, a feature of the business rather than the staff within that business. Businesses are simply entities with assets and capabilities but no cognitive processes, intelligence is a unique property of humans. Therefore there is a greater need to understand the social processes concerned in order to recognise this resource effectively. Second, that “e‐business” is distinct from “business”. Uses original research in the area of technological innovation as the basis for developing a wider argument with respect to e‐business. Argues that what is currently referred to as e‐business is a relatively poorly developed bundle of technologies that have yet to achieve full application in order to deliver optimum benefit. Also discusses the e‐business phenomenon, the role of technology and the importance of a social perspective of business to give more insightful understanding of the interactions between these areas.
Synthesis of conjugates ofL-fucose andortho-carborane as potential agents for boron neutron capture therapy
Authors: Basak Prakriti , Lowary Todd L
Published: October 2002

The synthesis of three potential boron neutron capture therapy agents (68) is reported. The compounds synthesized are comprised of ortho-carborane covalently attached to L-fucose via C-6. Incorporation of the carborane moiety was achieved either through the reaction of an L-fucose-derived alkyne with decaborane or by the coupling of a 6-amino-L-galactopyranose derivative with carborane carboxylic acid chloride (18).Key words: L-fucose, fucosyltransferase, boron neutron capture therapy, ortho-carborane.
On expanding the repertoire of glycosynthases: Mutant β-galactosidases forming β-(1,6)-linkages
Authors: Jakeman David L , Withers Stephen G
Published: October 2002

Oligosaccharide synthesis by enzymatic processes offers the potential for thrusting oligosaccharides to the forefront of pharmaceutical research, in part, due to expedient and scalable reaction protocols. Glycosynthases are an emerging class of mutant enzymes capable of synthesizing glycosidic linkages in high yield. We report a new glycosynthase enzyme generated by a point mutation of E. coli β-galactosidase that condenses α-galactosyl fluoride with aryl glucosides forming a β-(1,6) glycosidic linkage. A further point mutation within the enzyme, proximal to the active site, increases the yields significantly.Key words: glycosyl transfer, glycosynthase, enzymatic oligosaccharide synthesis. tétrahydrooxazine, isofagomine, iminosucres, inhibiteurs de glycosidases.[Traduit par la Rédaction]
Investigation of the reactivity difference between thioglycoside donors with variant aglycon parts
Authors: Lahmann Martina , Oscarson Stefan
Published: October 2002

The reactivity of perbenzoylated thioglycosides with various thiol aglycons has been compared and quantified using competitive glycosylation experiments. Methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside was employed as acceptor and DMTST as a promoter. The reactivity was found, as expected, to depend on the electron donating properties of the aglycon. Hence, the most reactive donor, the cyclohexyl thioglycoside, was found to be about three times as reactive as the thioethyl glycoside, which in turn was twice as reactive as the thiomethyl donor. The thiophenyl donor was even less reactive, whereas p-halophenyl donors were inert under the glycosylation conditions used  but could be activated using NISTfOH as promoter. Furthermore, it was found that galactosyl donors were three to four times more reactive than the corresponding glucosyl derivative. These results allowed the design of an orthogonal coupling between thioglycosides with the same protecting groups (benzoyls) but with different thiol aglycons. Key words: thioglycosides, orthogonal glycosylations, competititive glycosylations.
A 19F nuclear magnetic resonance study of the conjugate BrønstedLewis superacid HSO3FSbF5. Part II.
Authors: Kühn-Velten Jobst , Bodenbinder Matthias , Bröchler Raimund , Hägele Gerhard , Aubke Friedhelm
Published: October 2002

Solutions of SbF5 in HSO3F with xSbF5 = 0.012 to 0.405 are studied by 500 MHz 1H NMR (299 K) and 471 MHz 19F NMR (213250 K), using NMR tubes fitted with fluoropolymer lining. The initial process during dissolution is the fast solvolysis of monomeric SbF5 in HSO3F according to SbF5 + nHSO3F [Formula: see text] SbF5  n(SO3F)n + nHF (n = 1, 2). All HF formed during solvolysis will no longer be removed by reaction with glass, but will remain in the superacid system. Besides participation in the fast formation of various fluoro-fluorosulfato anions [SbF6  n(SO3F)n] (n = 0, 1, 2) and acidium ions [H2X]+(solv.) (X= F, SO3F), HF is involved in slow-exchange reactions of the type [SbF6  n(SO3F)n](solv.) + HF [Formula: see text] [SbF7  n(SO3F)n 1](solv.) + HSO3F (n = 1, 2) detected because of a delay of 3 months between sample preparation and measurements and confirmed by repeating theses measurements after a further 3 months. There are three notable differences to our earlier study, affecting concentrations of the fluoro-fluorosulfato antimonate anions observed: (i) in dilute solutions [SbF6] is formed in high concentrations (34.776.1%), with [Sb2F11] now clearly detected at intermediate to high SbF5 concentrations (up to 5.8%); (ii) bis-fluorosulfato anions (cis-, trans-[SbF4(SO3F)2]) are found in much lower concentrations only, which decrease further with time, while tris-fluorosulfato anions ([SbF3(SO3F)3]) are now no longer observed; (iii) these reduced concentrations of poly-fluorosulfato anions in dilute solutions are responsible for the formation of fewer µ-SO3F-oligomers at lower concentrations, when more SbF5 is added. As a consequence, the HSO3FSbF5 magic acid system is now less complex than found previously and only seven anionic species are clearly observed. Key words: superacids, antimony(V) fluoroanions, 1H NMR, 19F NMR, solvolysis.
Synthesis and solid-state molecular structures of bis- and mono-nitrosobenzene complexes of ruthenium porphyrins
Authors: Lee Jonghyuk , Twamley Brendan , Richter-Addo George B
Published: October 2002

Bis-nitrosobenzene complexes of the form (por)Ru(PhNO)2 (por = TPP, TTP; TPP = tetraphenylporphyrinato dianion, TTP = tetratolylporphyrinato dianion) have been prepared in good yields from the reaction of the (por)Ru(CO) precursor with excess PhNO in dichloromethane. The IR spectra of the complexes (as KBr pellets) displayed new bands at ~1348 cm1, due to υNO. The solid-state molecular structure of (TPP)Ru(PhNO)2 was determined by single-crystal X-ray diffraction, and revealed that the PhNO ligands are bound to the Ru center via the N-binding mode. Reactions of the (por)Ru(PhNO)2 complexes with excess 1-methylimidazole gave the mono-nitrosobenzene complexes (por)Ru(PhNO)(1-MeIm). The IR spectra revealed a lowering of υNO in these mononitrosobenzene derivatives by ~27 cm1, a feature consistent with the replacement of one π-acid PhNO ligand with the more basic 1-MeIm ligand. The solid-state molecular structure of (TPP)Ru(PhNO)(1-MeIm) reveals, in addition to the N-binding of the PhNO ligand, an essentially parallel arrangement of the C-N-O (of PhNO) and imidazole planes; this is in contrast with the (TPP)Ru(PhNO)2 complex, in which the C-N-O planes (of PhNO) are essentially perpendicular.Key words: nitroso, X-ray, ruthenium, porphyrin, imidazole.
Landscape analysis of risk factors for white pine blister rust in the Mixed Forest Province of Minnesota, U.S.A.
Authors: White Mark A , Brown Terry N , Host George E
Published: October 2002

The abundance of eastern white pine (Pinus strobus L.) has been significantly reduced in northeastern Minnesota over the past 120 years. White pine blister rust (WPBR), a commonly lethal fungal disease of white pine, was introduced in Minnesota in approximately 1914 and now, along with other factors such as herbivore browsing, poses a major challenge to attempts to reestablish white pines in the region. A map delineating broad WPBR hazard zones for the Lake States region was prepared in 1964. We created a higher resolution map that estimates the spatial variability of WPBR hazard in the Laurentian Mixed Forest Province of Minnesota using modern geographic information system techniques and readily available spatial databases. The new map has significantly higher resolution than the old and demonstrates that even within areas previously classified as "high hazard", there are significant acreages of "low-hazard" areas where white pine regeneration may be possible. Our analyses are consistent with previous work in the Lake States region, showing that climate, topographic characteristics, and distance from water bodies and wetlands have a strong influence on WPBR infection hazard. We also present methods for analyzing forest conditions at regional scales using commonly available spatial data sets.
STATISTICAL PROPERTIES OF THE AUSTRALIAN "ALL ORDINARIES" INDEX
Authors: STORER ROBIN , GUNNER SUSAN M.
Published: October 2002

Price changes of the primary index of the Australian Stock Market are analyzed over a period of about 20 years. The probability distribution of the relative changes in the index (returns) satisfies a distribution which is almost independent of the time interval chosen to measure the change. The distribution is consistent with the analysis of New York and other stock exchanges and also seems to satisfy a power law with exponent consistent with an inverse cubic law. If the data are separated into positive and negative returns this conclusion is not justified, particularly for the rising market. Thus there seems to be a significant asymmetry in the distribution.
Compressibility to 7 GPa at 298 K of the protonated octahedral framework mineral burtite, CaSn(OH)6
Authors: Welch M. D. , Crichton W. A.
Published: October 2002

The equation of state of synthetic deuterated burtite, CaSn(OD)6, has been determined to 7.25 GPa at 298 K by synchrotron X-ray powder diffraction. Fitting to a third-order Birch-Murnaghan equation of state gives K0 = 44.7(9) GPa and K0′ = 5.3(4). A second-order fit gives K0 = 47.4(4) GPa. Within experimental error the two fits are indistinguishable over the pressure range studied. The decrease in the a parameter with pressure is smooth and no phase transitions were observed. Burtite is much more compressible (by a factor of three or four) than CaSnO3 and CdSnO3 perovskites, indicating that the absence of a cavity cation has a major effect upon the compressibility of the octahedral framework. Burtite is also markedly more compressible than the closely-related mineral stottite FeGe(OH)6 (K0 = 78 GPa). Their different compressibilities correlate with the relative compressibilities of stannate and germanate perovskites. Although different octahedral compressions are likely to be the primary reason for the different compressibilities of burtite and stottite, we also consider the possible secondary role of hydrogen-bonding topology in affecting the compressibilities of protonated octahedral frameworks. Burtite and stottite have different hydrogen-bonding topologies due to their different octahedral-tilt system. Burtite, space group Pn and tilt system a+a+a+, has a hydrogen-bonded network of linked four-membered rings of O-H…O linkages, whereas stottite, space group P42/n and tilt system a+a+c−, has <100> O-H…O crankshafts and isolated four-membered rings. These different hydrogen-bonded configurations lead to different bracing of the empty cavity sites by the O-H…O linkages and very different hydrogen-bonding connectivities in these two minerals that may also enhance the difference between their compressibilities.
HRTEM observations of structural and chemical modulations in cosalite and its relationship to the lillianite homologues
Authors: Pring A. , Etschmann B.
Published: October 2002

The results of a HRTEM and electron diffraction investigation of a Cu- and Ag-rich cosalite, Cu1.2Ag0.9Pb6.7Bi8.2S20, from Ivigtut, Greenland, are presented. Electron diffraction patterns down [001] show pairs of satellite reflections at Gp±~1/8[140]* andGp±~1/8[40]* in addition to the strong Bragg reflections of the underlying average structure. The superlattice corresponds to a compositional and displacive modulationG±qprimwhereqprimis the primary modulation vector 1/8[140]*. The superlattice is attributed to coupled Ag/Pb/Bi and Cu/□ ordering and associated structural relaxation. The HRTEM images show a complex moire texture due to the structural modulations. Cosalite from Ivigtut, Greenland, also forms coherent intergrowths with members of the lillianite–gustavite series (Pb3Bi2S6–PbAgBi3S6). A model for the intergrowth between the structures is presented based on sharing both S and Pb atoms in the PbS-like slabs in both structures along [010]cosalite.
Ultralarge multimers of von Willebrand factor form spontaneous high-strength bonds with the platelet glycoprotein Ib-IX complex: studies using optical tweezers
Authors: Arya Maneesh , Anvari Bahman , Romo Gabriel M. , Cruz Miguel A. , Dong Jing-Fei , McIntire Larry V. , Moake Joel L. , López JoséA.
Published: October 2002

Ultralarge von Willebrand factor (ULVWF) multimers have been implicated in the pathogenesis of the catastrophic microangiopathic disorder, thrombotic thrombocytopenic purpura. Spontaneous ULVWF binding to platelets has been ascribed to increased avidity due to the greatly increased number of binding sites for platelets (the A1 domain) per molecule. To address the mechanism of enhanced ULVWF binding to platelets, we used optical tweezers to study the unbinding forces from the glycoprotein Ib-IX (GP Ib-IX) complex of plasma VWF, ULVWF, and isolated A1 domain. The unbinding force was defined as the minimum force required to pull ligand-coated beads away from their attachment with GP Ib-IX–expressing cells. Beads coated with plasma VWF did not bind to the cells spontaneously, requiring the modulators ristocetin or botrocetin. The force required to break the ristocetin- and botrocetin-induced plasma VWF–GP Ib-IX bonds occurred in integer multiples of 6.5 pN and 8.8 pN, respectively, depending on the number of bonds formed. In contrast, beads coated with either ULVWF or A1 domain bound the cells in the absence of modulators, with bond strengths in integer multiples of approximately 11.4 pN for both. Thus, in the absence of shear stress, ULVWF multimers form spontaneous high-strength bonds with GP Ib-IX, while plasma VWF requires exogenous modulators. The strength of individual bonds formed with GP Ib-IX was similar for both ULVWF and the isolated A1 domain and greater than those of plasma VWF induced by either modulator. Therefore, we suggest that the conformational state of ULVWF multimers is more critical than their size for interaction with platelets.
Cholesterol is essential for macrophage inflammatory protein 1β binding and conformational integrity of CC chemokine receptor 5
Authors: Nguyen Dzung H. , Taub Dennis
Published: October 2002

The chemokine receptor, CCR5, is used as a human immunodeficiency virus coreceptor in combination with CD4 during transmission and early infection. CCR5 has been shown to be palmitoylated and targeted to cholesterol- and sphingolipid-rich membrane microdomains termed “lipid rafts.” However, the role of cholesterol and lipid rafts on chemokine binding and signaling through CCR5 remains unknown. We found that cholesterol extraction by hydroxypropyl-β-cyclodextrin (BCD) significantly reduced the binding and signaling of macrophage inflammatory protein 1β (MIP-1β) using CCR5-expressing CEM-NKR T cells. Reloading treated cells with cholesterol but not 4-cholesten-3-one, an oxidized form of cholesterol, restored MIP-1β binding to BCD-treated cells. Antibodies specific for distinct CCR5 epitopes lost their ability to bind to the cell surface after cholesterol extraction to varying degrees. Moreover, cells stained with fluorescently labeled MIP-1β extensively colocalized with the GM1 lipid raft marker while using anti-CCR5 antibodies; most of CCR5 on these cells only partially colocalized with GM1, suggesting that active ligand binding facilitates receptor association with lipid rafts or that raft association promotes a higher affinity conformation of CCR5. Together, these data demonstrate that cholesterol and lipid rafts are important for the maintenance of the CCR5 conformation and are necessary for both the binding and function of this chemokine receptor.
Autosomal dominant reticuloendothelial iron overload associated with a 3–base pair deletion in the ferroportin 1 gene(SLC11A3)
Authors: Devalia Vinod , Carter Kymberley , Walker Ann P. , Perkins Stephen J. , Worwood Mark , May Alison , Dooley James S.
Published: October 2002

We describe a family with autosomal dominant inheritance of increased body iron stores characterized by raised serum ferritin concentration and normal transferrin saturation. Liver biopsy showed iron deposition in Kupffer cells without fibrosis. The clinical features of HFE-related hemochromatosis were absent, as were the Cys282Tyr and His63Asp mutations. Venesection therapy was poorly tolerated, suggesting a defect in iron release from reticuloendothelial stores. A 3–base pair deletion in exon 5 of the ferroportin 1 gene (SLC11A3) predicting Val162 deletion was found in affected members, but not in unaffected individuals or in 100 control subjects. Consensus structural predictions of the transmembrane helices showed that the deletion is in the extracellular loop between the third and fourth predicted transmembrane helices and lies within a spatial cluster of other known ferroportin 1 mutations. These results indicate that this extracellular cluster is functionally important for iron transport, and its disruption leads to iron overload.
Phase 2 trial of imatinib mesylate in myelofibrosis with myeloid metaplasia
Authors: Tefferi Ayalew , Mesa Ruben A. , Gray Leigh A. , Steensma David P. , Camoriano John K. , Elliott Michelle A. , Pardanani Animesh , Ansell Stephen M. , Call Timothy G. , Colon-Otero Gerardo , Schroeder Georgene , Hanson Curtis A. , Dewald Gordon W. , Kaufmann Scott H.
Published: October 2002

In a phase 2 study, 23 patients with myelofibrosis with myeloid metaplasia were treated with imatinib mesylate at a constant dose of 400 mg/d. Treatment was held in 16 patients (70%), after 1 to 12 weeks, because of side effects (neutropenia, 6 patients; musculoskeletal pain, 5 patients; thrombocytosis, 4 patients; edema, 3 patients; diarrhea and hyperbilirubinemia, 1 patient). Including patients in whom retreatment at a reduced dose was possible, 11 patients (48%) were able to continue treatment beyond 3 months. None of the patients experienced a response in anemia, and only 2 had partial responses in splenomegaly. A greater than 50% increase in platelet count was documented in 11 (48%) patients, but not in those with baseline platelet counts of less than 100 × 109/L. In vitro, imatinib mesylate caused variable degrees of growth suppression of myeloid and erythroid progenitors that unfortunately did not translate into clinical benefit.
Engagement of ILT2/CD85j in Sézary syndrome cells inhibits their CD3/TCR signaling
Authors: Nikolova Maria , Musette Philippe , Bagot Martine , Boumsell Laurence , Bensussan Armand
Published: October 2002

Extensive phenotype analysis of cutaneous T-cell lymphoma (CTCL) malignant cell lines revealed surface expression of receptors usually not detected on normal circulating CD4+CD45RO+lymphocytes. We previously found that CTCL malignant cells express the killer cell immunoglobulinlike receptor (KIR) KIR3DL2/CD158k, whereas they fail to express the other KIRs. In the present study, we report for the first time that the CD85j/immunoglobulin (Ig)–like transcript 2 (ILT2) receptor is found on Sézary cell lines and on circulating Sézary malignant CD4+ cells, while it is hardly detectable on circulating CD4+ lymphocytes from healthy individuals. We demonstrate that ILT2 is functional on CTCL cells, as its triggering leads to the recruitment of Src homology 2 domain-containing tyrosine phosphatase (SHP-1) and to the specific inhibition of CTCL malignant cell proliferation induced by CD3/T-cell receptor (TCR) stimulation. Interestingly, we found that separated CD4+ILT2+ circulating malignant Sézary cells are less susceptible to anti-CD3 monoclonal antibody (mAb)–induced cell death than autologous CD4+ILT2− lymphocytes. Therefore, the resistance to apoptosis of Sézary cells may result from distinct mechanisms including cytokine-induced high levels of bcl-2 and specific expression of inhibitory receptors involved in lymphocyte survival.
Prognostic importance of measuring early clearance of leukemic cells by flow cytometry in childhood acute lymphoblastic leukemia
Authors: Coustan-Smith Elaine , Sancho Jose , Behm Frederick G. , Hancock Michael L. , Razzouk Bassem I. , Ribeiro Raul C. , Rivera Gaston K. , Rubnitz Jeffrey E. , Sandlund John T. , Pui Ching-Hon , Campana Dario
Published: October 2002

Early clearance of leukemic cells is a favorable prognostic indicator in childhood acute lymphoblastic leukemia (ALL). However, identification of residual leukemic cells by their morphologic features is subjective and lacks sensitivity. To improve estimates of leukemia clearance, we applied flow cytometric techniques capable of detecting 1 leukemic cell in 10 000 or more normal cells and prospectively measured residual leukemia in bone marrow samples collected on day 19 of remission-induction chemotherapy from 248 children with newly diagnosed ALL. In 134 samples (54.0%), we identified at least 0.01% leukemic cells (0.01%-< 0.1% in 51 samples [20.6%], 0.1%-< 1% in 36 [14.5%], and ≥ 1% in 47 [19.0%]). Among 110 children treated within a single chemotherapy program, the 5-year mean ± SE cumulative incidence of relapse or failure to achieve remission was 32.2% ± 6.5% for the 59 patients with 0.01% residual leukemic cells or greater on day 19 and 6.0% ± 3.4% for the 51 patients with less than 0.01% leukemic cells (P < .001). The prognostic value of day-19 bone marrow status defined by flow cytometry was superior to that defined by morphologic studies and remained significant after adjustment for other clinical and biologic variables. Lack of detectable leukemic cells on day 19 was more closely associated with relapse-free survival than was lack of detectable residual disease at the end of remission induction (day 46). Thus, approximately half of the children with ALL achieve profound clearance of leukemic cells after 2 to 3 weeks of remission-induction chemotherapy, and these patients have an excellent treatment outcome.
Factor V Leiden: The Copenhagen City Heart Study and 2 meta-analyses
Authors: Juul Klaus , Tybjærg-Hansen Anne , Steffensen Rolf , Kofoed Steen , Jensen Gorm , Nordestgaard Børge Grønne
Published: October 2002

Factor V Leiden (FVL) is associated with venous thrombosis; however, an association between FVL and arterial thrombosis remains controversial. We investigated FVL as a risk factor for myocardial infarction (MI), ischemic stroke (IS), or non-MI ischemic heart disease (non-MI–IHD). The design was 3 case-control studies and 3 prospective studies with 21 years' follow-up. The setting was the general population in Copenhagen, Denmark. The participants for The Copenhagen City Heart Study were 20- to 95-year-old participants without cardiovascular disease (control population, n = 7907) or participants diagnosed with MI (n = 469), IS (n = 231), or non-MI–IHD (n = 365). In addition, 3 independent patient populations from Copenhagen University Hospital with MI (n = 493), IS (n = 231), or non-MI–IHD (n = 448) were included. We measured FVL genotype; major cardiovascular risk factors; and MI, IS, and non-MI–IHD incidence and prevalence. Prevalences of FVL heterozygotes and homozygotes in control subjects from the general population were 7.7% and 0.2%. Odds ratios and relative risks of MI in FVL carriers (heterozygotes + homozygotes) versus noncarriers were 1.24 (95% confidence interval [CI], 0.91-1.69) and 0.83 (0.58-1.20) in case-control and prospective studies, respectively. Corresponding risks for IS were 0.92 (95% CI, 0.56-1.53) and 0.68 (0.45-1.04), and for non-MI–IHD 1.01 (95% CI, 0.71-1.44) and 0.97 (0.66-1.42). Findings from The Copenhagen City Heart Study suggest that FVL is not associated with MI, IS, or non-MI–IHD.
Epstein-Barr virus–specific CD8+ T cells that re-express CD45RA are apoptosis-resistant memory cells that retain replicative potential
Authors: Dunne Padraic J. , Faint Jeffery M. , Gudgeon Nancy H. , Fletcher Jean M. , Plunkett Fiona J. , Soares Maria Vieira D. , Hislop Andrew D. , Annels Nicola E. , Rickinson Alan B. , Salmon Mike , Akbar Arne N.
Published: October 2002

During acute infection, latent and lytic Epstein-Barr virus (EBV) epitope-specific CD8+ T cells have a CD45RO+CD45RA− phenotype. However, after resolution of the infection, a large proportion of these cells, particularly those specific for lytic viral epitopes, re-express the CD45RA molecule. The role of CD8+ CD45RA+ T cells in ongoing immunity to EBV and other viruses is unknown. We now demonstrate that, relative to their CD45RO+ counterparts, the EBV-specific CD8+ T cells that revert to CD45RA expression after acute infectious mononucleosis are not in cell cycle, have longer telomeres, and are more resistant to apoptosis partly because of increased Bcl-2 expression. However, the EBV-specific CD8+CD45RA+ T cells have shorter telomeres than the total CD8+ CD45RA+ T-cell pool and predominantly express low levels of the CCR7 chemokine receptor, indicating that they are not naive cells. In addition, EBV-specific CD8+CD45RA+ T cells can be induced to proliferate and exhibit potent cytotoxic activity against target cells loaded with specific peptide. Our results strongly suggest, therefore, that EBV-specific CD8+ CD45RA+ T cells represent a stabilized virus-specific memory pool and not terminally differentiated effector cells. The identification of mechanisms that enable stable virus-specific CD8+ T cells to persist after acute infection may lead to the enhancement of antiviral immunity in immunocompromised and elderly persons.
Sperm protein 17 (Sp17) is a suitable target for immunotherapy of multiple myeloma
Authors: Chiriva-Internati Maurizio , Wang Zhiqing , Salati Emanuela , Bumm Klaus , Barlogie Bart , Lim Seah H.
Published: October 2002

Sperm protein 17 (Sp17) is a protein recently identified as a novel cancer-testis (CT) antigen in multiple myeloma (MM). Because this tumor antigen demonstrates a very restricted normal tissue expression, Sp17 may be an excellent target for tumor vaccine of MM. In this study, we determined the ability to generate Sp17-specific HLA class I–restricted cytotoxic T lymphocytes (CTLs) from the peripheral blood of 4 patients with MM, 3 consecutive Sp17+patients, and 1 Sp17− patient. Dendritic cells were generated from monocytes of 4 patients with MM and used to present a recombinant Sp17 protein to autologous T cells. Following 4 rounds of antigen stimulation, the CTLs were tested for their ability to kill autologous targets in an Sp17-dependent and HLA-class I– restricted manner in standard cytotoxicity assays. Despite previous chemotherapy and the immunosuppression so often associated with MM, CTL generation was successful in all 4 patients, irrespective of the Sp17 status of their tumors. Most importantly, the CTLs were able to lyse autologous tumor cells that expressed Sp17. Tumor cell lysis in all cases appeared to be mainly mediated by perforin and could be blocked by concanamycin A. We conclude that Sp17 is a suitable target for immunotherapy of MM. Our findings provide the basis for a clinical study aimed at inducing a cellular immune response directed at Sp17+ MM.
Comparative analysis of Ig and TCR gene rearrangements at diagnosis and at relapse of childhood precursor-B–ALL provides improved strategies for selection of stable PCR targets for monitoring of minimal residual disease
Authors: Szczepański Tomasz , Willemse Marja J. , Brinkhof Bas , van Wering Elisabeth R. , van der Burg Mirjam , van Dongen Jacques J. M.
Published: October 2002

Immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements are excellent patient-specific polymerase chain reaction (PCR) targets for detection of minimal residual disease (MRD) in acute lymphoblastic leukemia (ALL), but they might be unstable during the disease course. Therefore, we performed detailed molecular studies in 96 childhood precursor-B–ALL at diagnosis and at relapse (n = 91) or at presumably secondary acute myeloid leukemia (n = 5). Clonal Ig and TCR targets for MRD detection were identified in 94 patients, with 71% of these targets being preserved at relapse. The best stability was found for IGK-Kde rearrangements (90%), followed byTCRG (75%), IGH (64%), and incompleteTCRD rearrangements (63%). Combined Southern blot and PCR data for IGH, IGK-Kde, and TCRDgenes showed significant differences in stability at relapse between monoclonal and oligoclonal rearrangements: 89% versus 40%, respectively. In 38% of patients all MRD-PCR targets were preserved at relapse, and in 40% most of the targets (≥ 50%) were preserved. In 22% of patients most targets (10 cases) or all targets (10 cases) were lost at relapse. The latter 10 cases included 4 patients with secondary acute myeloid leukemia with germline Ig/TCR genes. In 5 other patients additional analyses proved the clonal relationship between both disease stages. Finally, in 1 patient all Ig/TCR gene rearrangements were completely different between diagnosis and relapse, which is suggestive of secondary ALL. Based on the presented data, we propose stepwise strategies for selection of stable PCR targets for MRD monitoring, which should enable successful detection of relapse in most (95%) of childhood precursor-B–ALL.
High incidence of Kaposi sarcoma–associated herpesvirus–related non-Hodgkin lymphoma in patients with HIV infection and multicentric Castleman disease
Authors: Oksenhendler Eric , Boulanger Emmanuelle , Galicier Lionel , Du Ming-Qing , Dupin Nicolas , Diss Tim C. , Hamoudi Rifat , Daniel Marie-Thérèse , Agbalika Félix , Boshoff Chris , Clauvel Jean-Pierre , Isaacson Peter G. , Meignin Véronique
Published: October 2002

Multicentric Castleman disease (MCD) is a distinct type of lymphoproliferative disorder associated with inflammatory symptoms and interleukin 6 (IL-6) dysregulation. In the context of human immunodeficiency virus (HIV) infection, MCD is associated with Kaposi sarcoma–associated herpesvirus, also called human herpesvirus type 8 (KSHV/HHV8). Within a prospective cohort study on 60 HIV-infected patients with MCD, and a median follow-up period of 20 months, 14 patients developed KSHV/HHV8-associated non-Hodgkin lymphoma (NHL): 3 “classic” KSHV/HHV8+ Epstein-Barr virus–positive (EBV+) primary effusion lymphoma (PEL), 5 KSHV/HHV8+ EBV− visceral large cell NHL with a PEL-like phenotype, and 6 plasmablastic lymphoma/leukemia (3/3 KSHV/HHV8+ EBV−). The NHL incidence observed in this cohort study (101/1000 patient-years) is about 15-fold what is expected in the general HIV+ population. MCD-associated KSHV/HHV8+ NHL fell into 2 groups, suggesting different pathogenesis. The plasmablastic NHL likely represents the expansion of plasmablastic microlymphoma from the MCD lesion and progression toward aggressive NHL. In contrast, the PEL and PEL-like NHL may implicate a different original infected cell whose growth is promoted by the cytokine-rich environment of the MCD lesions.
Expression of ABO or related antigenic carbohydrates on viral envelopes leads to neutralization in the presence of serum containing specific natural antibodies and complement
Authors: Preece Andrew F. , Strahan Karen M. , Devitt James , Yamamoto Fumi-ichiro , Gustafsson Kenth
Published: October 2002

No definitive biologic function has been associated with the human ABO histo-blood group polymorphism, or any other terminal carbohydrate differences within or between closely related species. We have experimentally addressed the question of whether viral particles can become glycosylated as determined by the glycosylation (eg, ABO) status of the producer cell and as a result be affected by human serum containing specific natural antibodies (NAbs). Measles virus was produced in cells transfected with cDNA encoding, either human A-transferase, B-transferase, an inactive “O-transferase,” or a pig α1-3galactosyltransferase (α1-3GT) synthesizing the Galα1-3Gal structure. The viruses were shown to carry the same ABO structures as the cells; that is, A but not B if produced in A-type cells, and B but not A if produced in B-type cells. Only O was detected on the virus produced from O-type cells, whereas reduced amounts of O appeared on the A- and B-type viral particles. In addition, the Galα1-3Gal structure was transferred onto measles only when grown in human cells expressing this structure. When subjected to human preimmune sera, the A-type, the B-type, and the Galα1-3Gal viral particles were partially neutralized in a complement-dependent manner. However, the O-type or the Galα1-3Gal–negative viral particles were not neutralized. The neutralization appeared to be mediated by specific NAb, as judged by specific inhibition using synthetic A and Galα1-3Gal oligosaccharides. Such viral glycosylation may thus partly explain why the ABO antigens and other similar intraspecies as well as interspecies polymorphic carbohydrates have evolved and been maintained over long evolutionary periods.
Ex vivo development of functional human lymph node and bronchus-associated lymphoid tissue
Authors: Tirouvanziam Rabindra , Khazaal Ibrahim , N'Sondé Victoire , Peyrat Marie-Alix , Lim Annick , de Bentzmann Sophie , Fournié Jean Jacques , Bonneville Marc , Péault Bruno
Published: October 2002

We introduce a novel in vivo model of human mucosal immunity, based on the implantation of human fetal bronchial mucosa and autologous peribronchial lymph node (PLN) in the severe combined immunodeficiency (SCID) mouse. In the SCID host, human fetal bronchi implanted alone retain macrophages and mast cells but lose T cells. In contrast, fetal bronchi co-implanted with PLN contain, in addition to macrophages and mast cells, numerous T cells and B cells, often clustered in intramucosal bronchus-associated lymphoid tissue (BALT). Functionally, bronchus–PLN cografts are able to mount robust αβ and γδ T-cell–mediated immune responses to Pseudomonas aeruginosa and 3,4-epoxy-3-methyl-1-butyl-diphosphate challenges. No other autologous lymphoid organ (bone marrow, thymus, liver) allows for BALT development in co-implanted bronchi, which suggests special ontogenetic and functional relations between extramucosal PLN and intramucosal BALT. Overall, the bronchus–PLN cograft appears as a promising model for human bronchial immune development and function. Our study is the first to document long-term ex vivo maintenance of functional human lymph nodes as native appendices to mucosal tissue. Our results, therefore, suggest a simple strategy for developing similar experimental models of human immune function in other mucosae.
Restricted T-cell receptor β-chain usage by T cells autoreactive to β2–glycoprotein I in patients with antiphospholipid syndrome
Authors: Yoshida Kazue , Arai Takahide , Kaburaki Junichi , Ikeda Yasuo , Kawakami Yutaka , Kuwana Masataka
Published: October 2002

We recently identified CD4+ T cells that are autoreactive to β2-glycoprotein I (β2GPI) and that promote antiphospholipid antibody production in patients with antiphospholipid syndrome (APS). In this study, T-cell receptor (TCR) β chains of β2GPI-reactive T cells were examined in 8 β2GPI-responders, including 5 patients with APS and 3 healthy subjects, using polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) analysis combined with in vitro stimulation of peripheral blood T cells with recombinant β2GPI. The TCR Vβ segments that expanded oligoclonally after stimulation with β2GPI varied among responders, but the Vβ7 and Vβ8 segments were commonly detected in 6 and 4 β2GPI-responders, respectively. Analysis of the complementarity-determining region 3 sequence of β2GPI-reactive T cells revealed limited diversity, and all Vβ7+ TCRs had an amino acid motif of TGxxN/Q or minor variations. The Vβ8+ TCRs had another motif, PxAxxD/E. Surprisingly, an identical Vβ7+ TCRβ chain was used by β2GPI-reactive T cells in 3 patients with APS. There was no apparent difference in the TCRβ usage between APS patients and healthy responders. Some of the Vβ7+ TCRs with the TGxxN/Q motif detected by PCR-SSCP analysis were also used by β2GPI-specific CD4+ T-cell clones responsive to an immunodominant epitope containing the major phospholipid-binding site. Depletion of Vβ7+ or Vβ8+ T cells from the peripheral blood mononuclear cell cultures significantly inhibited in vitro anti-β2GPI antibody production in response to β2GPI. Our results indicate preferential usage of TCRβ chains by β2GPI-reactive T cells. These TCRβ chains can be reasonable targets for TCR-based immunotherapy for patients with APS.
Spectral karyotyping identifies new rearrangements, translocations, and clinical associations in diffuse large B-cell lymphoma
Authors: Nanjangud Gouri , Rao Pulivarthi H. , Hegde Abhijith , Teruya-Feldstein Julie , Donnelly Gerard , Qin Jing , Jhanwar Suresh C. , Zelenetz Andrew D. , Chaganti R. S. K.
Published: October 2002

Diffuse large B-cell lymphoma (DLBCL), a histologically well-defined subset of non-Hodgkin lymphoma, is clinically and genetically heterogenous. By G-banding, most cases showed complex hyperdiploid karyotypes and diverse cytogenetic abnormalities that included recurring and nonrecurring translocations, deletions, duplications, and marker chromosomes. While G-banding provided valuable leads to identification of specific rearrangements that enabled gene discovery and clinical correlations, many aberrations remained uncharacterized because of their complexity. The molecular cytogenetic technique spectral karyotyping (SKY), on the other hand, enables complete characterization of all aberrations in a tumor cell karyotype and, hence, precise quantitation of chromosome instability. We report here, for the first time, SKY analysis of a panel of 46 DLBCL cases previously analyzed by G-banding, ascertained at the Memorial Sloan-Kettering Cancer Center. This analysis provided a cytogenetic profile of DLBCL that was characterized by a higher level of instability, qualitatively as well as quantitatively, compared with G-banding. Thus, 551 breakpoints were detected by SKY, in contrast to the 295 by G-banding. Several new recurring breakpoints, translocations, and regions of gain and loss were identified, which included 13 breakpoints not previously identified by G-banding, 10 breakpoints that were underrepresented by G-banding, and 4 previously unrecognized translocations: der(14)t(3;14)(q21;q32), t(1;13)(p32;q14), t(1;7)(q21;q22), and der(6)t(6;8)(q11;q11). We identified new clinical associations involving recurring breakpoints detected by SKY. These studies emphasize the value of SKY analysis for redefinition of chromosomal instability in DLBCL to enhance gene discovery as well as clinical correlation analysis.
Dose-adjusted EPOCH chemotherapy for untreated large B-cell lymphomas: a pharmacodynamic approach with high efficacy
Authors: Wilson Wyndham H. , Grossbard Michael L. , Pittaluga Stefania , Cole Diane , Pearson Deborah , Drbohlav Nicole , Steinberg Seth M. , Little Richard F. , Janik John , Gutierrez Martin , Raffeld Mark , Staudt Louis , Cheson Bruce D. , Longo Dan L. , Harris Nancy , Jaffe Elaine S. , Chabner Bruce A. , Wittes Robert , Balis Frank
Published: October 2002

We hypothesized that incremental improvements in the cyclophosphamide-doxorubicin-vincristine-prednisone (CHOP) chemotherapy regimen through optimization of drug selection, schedule, and pharmacokinetics would improve outcome in patients with large B-cell lymphomas. A prospective multi-institutional study of administration of etoposide, vincristine, and doxorubicin for 96 hours with bolus doses of cyclophosphamide and oral prednisone (EPOCH therapy) was done in 50 patients with previously untreated large B-cell lymphomas. The doses of etoposide, doxorubicin, and cyclophosphamide were adjusted 20% each cycle to achieve a nadir absolute neutrophil count below 0.5 × 109/L. The median age of the patients was 46 years (range, 20-88 years); 24% were older than 60 years; and 44% were at high-intermediate or high risk according to International Prognostic Index (IPI) criteria. There was a complete response in 92% of patients, and at the median follow-up time of 62 months, the progression-free survival (PFS) and overall survival (OS) rates were 70% and 73%, respectively. Neither IPI risk factors nor the index itself was associated with response, PFS, or OS. Doses were escalated in 58% of cycles, and toxicity levels were tolerable. Significant inverse correlations were observed between dose intensity and age for all adjusted agents, and drug clearance of doxorubicin and free etoposide was also inversely correlated with age (r = −0.54 andP2 = .08 and r = −0.45 andP2 = .034, respectively). Free-etoposide clearance increased significantly during successive cycles (P2 = .015). Lymphomas with proliferation of at least 80% had somewhat lower progression and those expressing bcl-2 had significantly higher progression (P2 = .04). Expression of bcl-2 may discriminate the recently described activated B-like from germinal-center B-like large-cell lymphomas and provide important pathobiologic and prognostic information. Dose-adjusted EPOCH may produce more cell kill than CHOP-based regimens. Dynamic dose adjustment may overcome inadequate drug concentrations, particularly in younger patients, and compensate for increased drug clearance over time.
Autoimmunity in human primary immunodeficiency diseases
Authors: Arkwright Peter D. , Abinun Mario , Cant Andrew J.
Published: October 2002

Human primary immunodeficiency diseases are experiments of nature characterized by an increased susceptibility to infection. In many cases, they are also associated with troublesome and sometimes life-threatening autoimmune complications. In the past few years, great strides have been made in understanding the molecular basis of primary immunodeficiencies, and this had led to more focused and successful treatment. This review has 3 aims: (1) to highlight the variety of autoimmune phenomena associated with human primary immunodeficiency diseases; (2) to explore how primary immunodeficiencies predispose patients to autoimmune phenomena triggered by opportunistic infections; and (3) to consider the rationale for the current treatment strategies for autoimmune phenomena, specifically in relation to primary immunodeficiency diseases. Reviewing recent advances in our understanding of the small subgroup of patients with defined causes for their autoimmunity may lead to the development of more effective treatment strategies for idiopathic human autoimmune diseases.
Long-term repopulating ability of telomerase-deficient murine hematopoietic stem cells
Authors: Samper Enrique , Fernández Piedad , Eguı́a Raúl , Martı́n-Rivera Luis , Bernad Antonio , Blasco Marı́a A. , Aracil Miguel
Published: October 2002

Telomere length must be tightly regulated in highly proliferative tissues, such as the lymphohematopoietic system. Under steady-state conditions, the levels and functionality of hematopoietic-committed or multipotent progenitors were not affected in late-generation telomerase-deficient mice (mTerc−/−) with critically short telomeres. Evaluation of self-renewal potential of mTerc−/− day-12 spleen colony-forming units demonstrated no alteration as compared with wildtype progenitors. However, the replating ability of mTerc−/− granulocyte-macrophage CFUs (CFU-GMs) was greatly reduced as compared with wildtype CFU-GMs, indicating a diminished capacity of late-generation mTerc−/− committed progenitors when forced to proliferate. Long-term bone marrow cultures of mTerc−/−bone marrow (BM) cells show a reduction in proliferative capacity; this defect can be mainly attributed to the hematopoietic, not to the stromal, mTerc−/− cells. In serial and competitive transplantations, mTerc−/− BM stem cells show reduced long-term repopulating capacity, concomitant with an increase in genetic instability compared with wildtype cells. Nevertheless, in competitive transplantations late-generation mTerc−/− precursors can occasionally overcome this proliferative impairment and reconstitute irradiated recipients. In summary, our results demonstrate that late-generation mTerc−/− BM cells with short telomeres, although exhibiting reduced proliferation ability and reduced long-term repopulating capacity, can still reconstitute myeloablated animals maintaining stem cell function.
B7-CTLA4 interaction promotes cognate destruction of tumor cells by cytotoxic T lymphocytes in vivo
Authors: Bai Xue-Feng , Liu Jinqing , May Kenneth F. , Guo Yong , Zheng Pan , Liu Yang
Published: October 2002

Costimulatory molecules B7-1 and B7-2 (hereby collectively called B7) interact with CD28 and CTLA4 on T cells and promote antitumor immunity. The function of B7-CTLA4 interaction in antitumor CTL response remains controversial. Here we used CD28−/− and CD28+/− or CD28+/+ transgenic mice that express the T-cell receptor specific for an unmutated tumor antigen, P1A, and for tumor cells expressing a CTLA4-specific B7 mutant to evaluate the function of CD28-B7 and CTLA4-B7 interactions in induction and effector phases of antitumor immunity. We report that B7-CD28 and B7-CTLA4 interactions promote tumor rejection. However, this is achieved by distinct mechanisms. B7-CD28 interaction enhances T-cell clonal expansion, though a role for this interaction in the effector phase cannot be ruled out. In contrast, B7-CTLA4 interaction enhances the CTL-mediated destruction of tumors, but not T-cell clonal expansion.