bluuebunny/crossref_metadata_2025 huggingface dataset:
Involvement of nuclear factor‐xB in platelet‐activating factor‐mediated tumor necrosis factor‐α expression
Authors: Im Suhn Young , Han Su Ji , Ko Hyun Mi , Choi Jung Hwa , Chun Soon Bai , Lee Dong Geun , Ha Tai You , Lee Hern‐Ku
Published: March 2007

Tumor necrosis factor (TNF)‐α and platelet‐activating factor (PAF) are important mediators of inflammatory reactions, and their release is controlled by a positive feedback network. However, the regulatory mechanisms underlying the interaction of these two molecules are unknown. Within 10 min of the injection of lipopolysaccharide (LPS) into C57BL/6 mice, effects inducible by PAF such as anaphylactic shock‐like symptoms, disseminated intravascular coagulation, and hemorrhage in renal medullae were observed, and all these pathological changes were prevented by the PAF antagonist, BN 50739. The plasma level of PAF after LPS injection reached a peak at 5 min. TNF‐α gene expression was evident 20 min after LPS injection and was maximal at 40 min, and the level of serum TNF‐α reached a peak at 1 h. Pretreatment with BN 50739 inhibited LPS‐induced TNF‐α gene expression and protein synthesis in a dose‐dependent manner. Injection of PAF or treatment of the macrophage cell line, J774A.1, with PAF activated the transcription factor, nuclear factor (NF)‐xB, which is essential for inducible TNF‐α transcription. The activation of NF‐xB by PAF preceded the LPS‐mediated TNF‐α gene expression. Pretreatment with BN 50739 inhibited LPS‐induced mobilization of NF‐xB in a dose‐dependent manner in vivo as well as in vitro. These data suggest that PAF, which is released immediately or shortly after LPS injection, induces the expression of TNF‐α through the activation of NF‐xB.
Structural analysis of human γ3 intervening regions and switch regions: Implication for the low frequency of switching in IgG3‐deficient patients
Authors: Pan Qiang , Lindersson Ylva , Sideras Paschalis , Hammarström Lennart
Published: March 2007

High and low serum concentrations of IgG3 are associated with the human G3m(b) and G3m(g) allotypes, respectively. In the present study, we analyzed the structure of the Sγ3 and Iγ3, the switch frequency, switch breakpoints and the levels and initiation sites of Iγ3 transcripts both in normal blood donors expressing (b) or (g) allotypes as well as IgG3‐deficient (D) patients. A low switch frequency to γ3 was found in the (g) allotype IgG3D patients which may be caused in part by the allotype‐associated mutations in the Sγ3 region and in part by additional individual mutations observed in the A (SNAP) and B (SNIP/NF‐xB) sites in the Sγ3 repeat region. A higher Iγ3 germ‐line (GL) transcriptional rate was seen in cells from the IgG3D patient, suggesting that low levels of GL Iγ3 transcripts are not a major contributing factor to the defect. However, individual mutations in the Iγ3 region and differential splicing of GL Iγ3 transcripts were found which may affect the switching process.
Thymic T cell export is not influenced by the peripheral T cell pool
Authors: Gabor Melinda J. , Scollay Roland , Godfrey Dale I.
Published: March 2007

The peripheral T cell pool is maintained both by export of naive T cells from the thymus and by post‐thymic expansion of activated/memory T cells. However, it is not known whether the thymus can alter its output following peripheral T cell depletion. Using intrathymic injection of fluorescein isothiocyanate to detect recent thymic emigrants (RTE), we directly tested whether the thymus is able to alter the number of RTE or the CD4:CD8 ratio of RTE emigrating to the periphery in response to in vivo depletion of total peripheral T cells or CD4 T cells, respectively. Depletion of peripheral T cells was achieved with anti‐Thy‐1 or anti‐CD4, at doses that did not affect thymocyte numbers. Depletion of greater than 70% of peripheral T cells by treatment with anti‐Thy‐1 in vivo did not alter the number or cell cycle status of RTE trafficking to lymph nodes or spleen during the peripheral reconstitution phase (6, 9, 12 days). Similarly, depletion of the majority of CD4 T cells, which significantly reduced the peripheral CD4:CD8 T cell ratio, did not alter the total number or the proportion of CD4+ CD8− RTE in peripheral lymphoid organs. These data clearly indicate that thymic output is not influenced by downstream alterations in peripheral T cell pool size or CD4:CD8 ratio. Rather we contend that thymic T cell export is internally regulated by as yet undefined mechanisms.
Immune complexes are potent inhibitors of interleukin‐12 secretion by human monocytes
Authors: Berger Stefan , Chandra Ramon , Balló Hilmar , Hildenbrand Ralf , Stutte Hans Jochen
Published: March 2007

We have studied the effect of immune complexes (IC) on interleukin (IL)‐12 secretion by human monocytes in vitro. Two experimental models of IC were used. IC formed of tetanus toxoid and polyclonal anti‐tetanus toxoid antiserum as well as heat‐aggregated human serum IgG almost completely inhibited IL‐12 (p70 and p40) secretion induced by interferon‐γ and lipopolysaccharide in human blood‐derived monocytes. Neutralizing anti‐IL‐10 antibodies plus indomethacin restored IL‐12 secretion in the presence of IC to a high extent, indicating that IL‐10 and prostaglandin (PG) partially mediate the IC‐induced inhibition of IL‐12 secretion. However, neutralization of tumor necrosis factor (TNF)‐α by specific antibodies also incompletely restored IL‐12 secretion. Indeed, monocytes secrete high levels of TNF‐α upon stimulation by IC. We found that exogenously added TNF‐α caused a profound inhibition of monocytic IL‐12 secretion in the absence of IC, again mediated via the induction of IL‐10 and PG. In summary, IC inhibit IL‐12 secretion via TNF‐α‐induced IL‐10 and PG synthesis. We conclude that IC, typically appearing in the course of chronic inflammatory processes, may influence the balance between Th1 and Th2 responses and may thus contribute to a deprivation of cell‐mediated immune responses.
Role of amino acid position 70 in the binding affinity of p50.1 and p58.1 receptors for HLA‐Cw4 molecules
Authors: Biassoni Roberto , Pessino Anna , Malaspina Angela , Cantoni Claudia , Bottino Cristina , Sivori Simona , Moretta Lorenzo , Moretta Alessandro
Published: March 2007

In an attempt to identify the amino acid position(s) of the HLA‐C‐specific p58.1/p50.1 natural killer cell receptors that determine the binding affinity for their ligand, we used soluble fusion proteins formed by the ectodomain of either receptor and the Fc portion of human IgG1. We show that the soluble p50.1 (activating) receptor binds weakly to 221‐Cw4 transfectants. In contrast, the soluble p58.1 (inhibitory) receptor binds with high affinity. A single amino acid mutation at position 70, obtained by site‐directed mutagenesis, was found to affect the binding affinity of both the p50.1 and the p58.1 receptors. Thus, sub‐stitution in p50.1 of lysine 70 by threonine (typical of the inhibitory p58.1 molecule) resulted in a dramatic increase in binding affinity, comparable to that of the p58.1 molecule. On the other hand, substitution of threonine 70 by lysine in p58.1 almost abolished binding to 221‐Cw4 cells. Our present data indicate that a single amino acid difference greatly influences the p58.1/p50.1 affinity for their HLA‐C ligand and suggests a possible role of position 70 as a contact site in the natural killer cell receptor/major histocompatibility complex class I interaction.
Identification of a T cell lineage‐specific RNA/DNA helicase and its cell surface expression during intrathymic education of αβ and γδ T cells
Authors: Miazek Arkadiusz , Brockhaus Manfred , Langen Hanno , Braun Andrea , Kisielow Pawel
Published: March 2007

Despite ubiquitous expression of the gene, RNA/DNA helicase protein was found to be expressed specifically in all cells of the T cell lineage. Interestingly, immature thymocytes that are rearranging T cell receptor (TCR) genes express the helicase strongly on the cell surface and the surface expression is terminated upon engagement of functional TCR by positively selecting ligands. This provides the first evidence that a protein that binds nucleic acids can directly contact the extracellular environment in a developmentally controlled manner. Our discovery of a novel molecular link between the cell surface and nuclear events specific for thymocytes suggests that thymic education is supervised by a previously unknown molecular mechanism, which can now be experimentally explored.
CD28 can promote T cell survival through a phosphatidylinositol 3‐kinase‐independent mechanism
Authors: Collette Yves , Razanajaona D. , Ghiotto M. , Olive Daniel
Published: March 2007

Phosphatidylinositol 3(Pl3)‐kinase is implicated in various biological responses, including protection from apoptosis, although its role in antigen‐induced T cell death and the molecular effectors it triggers remains ill‐defined. Here, we investigated the role of Pl3‐kinase activity in the prevention of T cell receptor/CD3‐induced cell death by CD28. Pl3‐kinase inhibitors blocked the up‐regulation of Bcl‐XL by CD28, without impairing the prevention of T cell receptor/CD3‐triggered apoptosis by CD28, hence showing the existence of a cell‐survival pathway independent of Pl3‐kinase activity and up‐regulation of Bcl‐XL. Instead, we show that up‐regulation of FasL which is instrumental in CD3‐induced apoptosis was prevented upon CD28 co‐stimulation. These results indicate that Pl3‐kinase couples CD28 to Bcl‐XL up‐regulation and provide a molecular basis for the role of CD28 in cell survival through a Pl3‐kinase‐independent mechanism including FasL down‐regulation.
Major role of the soluble interleukin‐6/interleukin‐6 receptor complex for the proliferation of interleukin‐6‐dependent human myeloma cell lines
Authors: Gaillard Jean‐Philippe , Liautard Janny , Klein Bernard , Brochier Jean
Published: March 2007

Interleukin‐6 (IL‐6) is a proinflammatory cytokine which possesses a central growth factor activity for certain tumor cells such as plasma cells in multiple myeloma (MM). Upon binding of IL‐6, soluble IL‐6 receptor (sIL‐6R) has been shown to retain its affinity for IL‐6 and to associate with the signal‐transducing gp130 chain. Therefore, contrary to the majority of soluble cytokine receptors, it plays an agonist role in IL‐6 signaling. In order to test its physiological importance as compared to that of its membrane counterpart, we studied cells from two myeloma cell lines which need exogenous IL‐6 to proliferate and release sIL‐6R into their culture supernatant. Using a new culture system where the supernatant recirculated permanently through an anti‐IL‐6R affinity column, all sIL‐6R was removed from the culture medium throughout the culture period. Under these conditions IL‐6‐dependent cells were unable to grow in the presence of physiological concentrations of IL‐6, showing the major role of the sIL‐6R for sustaining the proliferation of these cell lines. Increasing IL‐6 concentrations well over the physiological values allowed the cells to proliferate again. No effect was seen when sIL‐6R was removed from the supernatant of an IL‐6‐independent myeloma cell line. These results show that the levels of circulating sIL‐6R (and thus those of IL‐6/sIL‐6R complex) are worth looking at in pathologies involving IL‐6 hyperactivity.
Endothelial cells in chorionic fetal vessels of first trimester placenta express HLA‐G
Authors: Blaschitz Astrid , Lenfant Françoise , Mallet Valérie , Hartmann Michaele , Bensussan Armand , Geraghty Daniel E. , Le Bouteiller Philippe , Dohr Gottfried
Published: March 2007

Using four different HLA‐G‐recognizing monoclonal antibodies (mAb), we investigated whether this nonclassical HLA class I molecule could be expressed in placental cell types other than extravillous cytotrophoblasts (evct) in which HLA‐G has already been detected. Immunohistochemical analysis was performed on serial cryosections of first trimester placenta as well as on maternal decidual tissue. In addition to some proliferative evct, the recently described BFL.1 mAb also slightly stained some villous cytotrophoblast (vct) stem cells located near cell columns and cell islands, which until now have been considered as HLA‐G negative. The same staining pattern was obtained with the 16G1 mAb raised against the soluble HLA‐G isoform, whereas neither 87G nor HCA2 reacted with vct but did strongly label the invasive populations of evct, including interstitial and endovascular trophoblasts. Surprisingly, BFL.1 strongly and reproducibly stained endothelial cells in the fetal capillaries present in the mesenchymal core of the chorionic villi, whereas none of the other surrounding cellular components were stained. The same specific labeling was obtained, although with less intensity, with the three other HLA‐G‐recognizing mAb. In contrast, maternal endothelial cells present in spiral arteries of the decidua parietalis remained unstained. This unexpected cellular localization suggests that HLA‐G may be present as a soluble form during the whole period of fetal vascularization and/or exert a nonimmunological function related to the endothelial cell type, in particular in the angiogenesis process which is highly active, until term, in chorionic villi.
Protein tyrosine kinase Syk is involved in Thy‐1 signaling in rat basophilic leukemia cells
Authors: Tolar Pavel , Dráberová Lubica , Dráber Petr
Published: March 2007

Thy‐1, a glycosyl‐phosphatidylinositol‐anchored surface glycoprotein, has been shown to possess transmembrane signaling capacity. In rat mast cells and rat basophilic leukemia cells (RBL) aggregation of surface Thy‐1 with antibodies triggers a series of intracellular events, resembling those induced by aggregation of the high‐affinity receptor for IgE (FcεRI), including tyrosine phosphorylation of multiple proteins and release of secretory components. Unlike the FcεRI‐mediated activation, where both the membrane‐associated protein tyrosine kinase (PTK) Lyn and the cytoplasmic PTK Syk are responsible for initiating the signaling cascade, only Lyn has been implicated in Thy‐1‐mediated activation in RBL cells. Here we report that Syk is also rapidly tyrosine phosphorylated upon Thy‐1 cross‐linking. Increased Syk tyrosine phosphorylation is observed only in cells in which extensive aggregation of Thy‐1 is induced by two layers of cross‐linking reagents. RBL‐derived mutant cells deficient in the expression of surface Thy‐1 and transfectants re‐expressing surface Thy‐1 were used to exclude the possibility that Syk activation reflects an interaction of the cross‐linking reagents with surface molecules other than Thy‐1. As FcεRI γ subunits are well known to promote activation of Syk and its recruitment to membrane complexes, we also investigated the role of these subunits in Thy‐1‐mediated Syk activation, using RBL‐derived mutant cells deficient in the expression of FcεRI γ subunits and their revertants. Consistent with the lack of FcεRI expression, no IgE‐induced response could be elicited, while Thy‐1‐inducible Syk phosphorylation was preserved. Our results suggest that Syk might be one of the kinases responsible for signal propagation upon Thy‐1 cross‐linking in a FcεRI‐independent pathway.
Four types of Ca2+ signals in naive CD8+ cytotoxic T cells after stimulation with T cell agonists, partial agonists and antagonists
Authors: Bachmann Martin F. , Mariathasan Sanjeev , Bouchard Denis , Speiser Daniel E. , Ohashi Pamela S.
Published: March 2007

Stimulation of T cells via the T cell receptor (TCR) leads to an increase intracellular in free Ca2+ levels ([Ca2+]i) and the activation of the MAP kinase signaling pathway. This study analyzes for the first time Ca2+ fluxes in naive cytotoxic T cells stimulated with full agonists, partial agonists, or antagonists. Four different types of Ca2+ responses could be observed. Full agonists triggered a strong and sustained increase in [Ca2+]i. In contrast, partial T cell agonists induced either a strong but transient Ca2+ flux or very low to no increases in [Ca2+]i, while T cell antagonists failed to induce any measurable Ca2+ flux. The ability of peptides to induce elevated [Ca2+]i perfectly paralleled their ability to trigger TCR internalization and T cell activation. Thus, stimulation of naive cytotoxic T cells with a panel of defined altered peptide ligands reveals a consistent picture, where Ca2+ fluxes predict agonist, partial agonist and antagonist properties of peptides.
Major histocompatibility complex class I presentation of exogenously acquired minor alloantigens initiates skin allograft rejection
Authors: Oukka Mohamed , Galou Maria , Belkaid Yasmine , Tricotet Vivianne , Riche Nicole , Reynes Michel , Kosmatopoulos Konstadionos
Published: March 2007

Major histocompatibility complex (MHC) class I molecules present peptides from endogenous proteins. However, in some cases class I‐restricted peptides can also derive from exogenous antigens. This MHC class I exogenous presentation could be involved in minor histocompatibility antigen (mHAg)‐disparate allograft rejection when donor alloantigens are not expressed in graft antigen‐presenting cells (APC) that initiate the rejection mechanism. Here we addressed this question by using a skin graft experimental model where donors (H‐2b or H‐2d Tgβ‐gal mice) expressed the mHAg like β‐galactosidase (β‐gal) in keratinocytes but not in Langerhans' cells (LC) which have an APC function. Rejection of Tgβ‐gal skin by a β‐gal‐specific CD8 cytotoxic T lymphocyte (CTL) effector mechanism should require presentation by donor and/or recipient LC of MHC class I‐restricted peptides of exogenous β‐gal shed by keratinocytes. Indeed, our results showed that 1) H‐2b Tgβ‐gal skin was rejected by H‐2bxs and H‐2bxd recipients; 2) rejection was mediated by β‐gal‐specific CD8+ CTL effectors; and 3) H‐2bxd mice having rejected H‐2b Tgβ‐gal skin generated β‐gal‐specific CTL restricted by H‐2b and H‐2d class I molecules and rejected subsequently grafted H‐2d Tgβ‐gal skin in an accelerated fashion, demonstrating that recipient LC have presented exogenous β‐gal‐derived MHC class I epitopes. These results lead to the conclusion that MHC class I exogenous presentation of donor mHAg can initiate allograft rejection.
Immunization with immune complex alters the repertoire of antigen‐reactive B cells in the germinal centers
Authors: Nie Xiaobo , Basu Subhendu , Cerny Jan
Published: March 2007

The differentiation of memory B cells in germinal centers (GC) is selectively enhanced upon administration of antigen‐antibody complexes. To characterize the repertoire of this response, we examined the rearranged immunoglobulin heavy chain variable (VH) genes from mouse splenic GC after a single immunization with either antigen, nitrophenyl (NP) hapten coupled to keyhole limpet hemocyanin, or with a preformed complex of antigen with a monoclonal anti‐NP antibody of γ1 isotype. Among antigen‐immunized mice, NP‐reactive GC B cell populations in the antigen‐induced GC consisted mostly of cells expressing the canonical V186.2 gene which contained, on average, 0.8 point mutations/VH gene by day 8 after immunization. These results are indicative of the beginning of somatic hypermutation and consistent with previously published analyses of NP antigen‐driven GC. In contrast, the NP‐specific B cells in GC that were elicited by administration of immune complex represented a heterogeneous cell population expressing nine different germ‐line segments of the V186.2/V3 (J558) gene family, i.e. V23, V24.8, C1H4, V3, CH10, V165.1, V102, V671.5 and V186.2. Moreover, the average frequency of mutations in these genes was 1.7, reaching up to 4 mutations/VH in some GC. Administration of the antigen NP in complex with specific antibody apparently alters the process of interclonal competition in the GC and results in loss of dominance by V186.2+ cells and nearly stochastic representation of diverse clono‐types. These results suggest an important feedback regulation of the B cell repertoire by antibody and indicate a role for immune complexes in the activation of somatic hypermutation.
Anti‐apoptotic signals of granulocyte‐macrophage colony‐stimulating factor are transduced via Jak2 tyrosine kinase in eosinophils
Authors: Simon Hans‐Uwe , Yousefi Shida , Dibbert Birgit , Levi‐Schaffer Francesca , Blaser Kurt
Published: March 2007

Cytokine‐mediated inhibition of eosinophil apoptosis is a mechanism causing tissue eosinophilia. Previously published work suggested that activation of the Lyn‐Ras‐Raf‐1‐MAP kinase pathway is obligatory for prevention of eosinophil apoptosis by eosinophil hematopoietins. We demonstrate herein that activation of freshly isolated human blood eosinophils by granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) is associated with increased tyrosine phosphorylation of Jak2. The tyrosine kinase blocker, tyrphostin B42, prevented activation of Jak2 but not Lyn, suggesting that Jak2 is the specific target for tyrphostin B42 in eosinophils. In addition, since Lyn remained unaffected by tyrphostin B42, it is unlikely that Jak2 is required for Lyn activation in this model. To test whether tyrosine phosphorylation of Jak2 is linked to GM‐CSF‐mediated prolonged eosinophil survival, we determined the effect of tyrphostin B42 on eosinophil viability and apoptosis. Prevention of Jak2 activation by tyrphostin B42 was associated with the inability of GM‐CSF to prevent eosinophil apoptosis. These data suggest that disruption of not only the Lyn‐Ras‐Raf‐1‐MAP kinase but also the Jak‐STAT pathway blocks the ability of eosinophil survival factors to prevent apoptosis in eosinophils.
High‐resolution genomic profiles of breast cancer cell lines assessed by tiling BAC array comparative genomic hybridization
Authors: Jönsson Göran , Staaf Johan , Olsson Eleonor , Heidenblad Markus , Vallon‐Christersson Johan , Osoegawa Kazutoyo , de Jong Pieter , Oredsson Stina , Ringnér Markus , Höglund Mattias , Borg Åke
Published: March 2007

A BAC‐array platform for comparative genomic hybridization was constructed from a library of 32,433 clones providing complete genome coverage, and evaluated by screening for DNA copy number changes in 10 breast cancer cell lines (BT474, MCF7, HCC1937, SK‐BR‐3, L56Br‐C1, ZR‐75‐1, JIMT1, MDA‐MB‐231, MDA‐MB‐361, and HCC2218) and one cell line derived from fibrocystic disease of the breast (MCF10A). These were also characterized by gene expression analysis and found to represent all five recently described breast cancer subtypes using the “intrinsic gene set” and centroid correlation. Three cell lines, HCC1937 and L56BrC1 derived from BRCA1 mutation carriers and MDA‐MB‐231, were of basal‐like subtype and characterized by a high frequency of low‐level gains and losses of typical pattern, including limited deletions on 5q. Four estrogen receptor positive cell lines were of luminal A subtype and characterized by a different pattern of aberrations and high‐level amplifications, including ERBB2 and other 17q amplicons in BT474 and MDA‐MB‐361. SK‐BR‐3 cells, characterized by a complex genome including ERBB2 amplification, massive high‐level amplifications on 8q and a homozygous deletion of CDH1 at 16q22, had an expression signature closest to luminal B subtype. The effects of gene amplifications were verified by gene expression analysis to distinguish targeted genes from silent amplicon passengers. JIMT1, derived from an ERBB2 amplified trastuzumab resistant tumor, was of the ERBB2 subtype. Homozygous deletions included other known targets such as PTEN (HCC1937) and CDKN2A (MDA‐MB‐231, MCF10A), but also new candidate suppressor genes such as FUSSEL18 (HCC1937) and WDR11 (L56Br‐C1) as well as regions without known genes. The tiling BAC‐arrays constitute a powerful tool for high‐resolution genomic profiling suitable for cancer research and clinical diagnostics. © 2007 Wiley‐Liss, Inc.
Frequent fusion of the CRTC1 and MAML2 genes in clear cell variants of cutaneous hidradenomas
Authors: Winnes Marta , Mölne Lena , Suurküla Mart , Andrén Ywonne , Persson Fredrik , Enlund Fredrik , Stenman Göran
Published: March 2007

Fusion of the CREB regulated transcription coactivator CRTC1 (a.k.a. MECT1, TORC1, or WAMTP1) to the Notch coactivator MAML2 is a characteristic feature of low‐grade mucoepidermoid carcinomas of salivary and bronchial glands. The CRTC1–MAML2 fusion protein acts by inducing transcription of cAMP/CREB target genes, and this activity is crucial for the transforming properties of the protein. Here we show that the CRTC1–MAML2 gene fusion is also frequent in benign hidradenomas of the skin. FISH and RT‐PCR analyses revealed that hidradenomas are genetically heterogeneous, and that 10 of the 20 tumors analyzed (50%) contained the CRTC1–MAML2 gene fusion and expressed the resulting fusion transcript. Immunohistochemical analysis demonstrated expression of the fusion protein in the majority of tumor cells, including clear cells, poroid cells, and cells with epidermoid and ductal differentiation. In addition, we could show that all fusion‐positive tumors were morphologically distinguished by the presence of more or less abundant areas of clear cells whereas all fusion‐negative tumors lacked clear cells. Our findings thus demonstrate that the CRTC1–MAML2 gene fusion is frequent in hidradenomas and is associated with clear cell variants of this tumor. Taken together, the present and previous observations indicate that the CRTC1–MAML2 fusion is etiologically linked to benign and low‐grade malignant tumors originating from diverse exocrine glands rather than being linked to a separate tumor entity. © 2007 Wiley‐Liss, Inc.
Prominent oligodendrocyte genesis along the border of spinal contusion lesions
Authors: Tripathi Richa , McTigue Dana M.
Published: March 2007

Oligodendrocyte (OL) loss and axon demyelination occur after spinal cord injury (SCI). OLs may be replaced, however, by proliferating NG2+ progenitor cells. Indeed, new OLs have been noted in ventral white matter after SCI. Since tissue adjacent to lesion cavities is exposed to different mediators compared with outlying spared tissue, the authors used a rat SCI model to compare NG2 cell proliferation and OL genesis adjacent to lesion cavities with that in spared tissue closer to meninges. NG2 cells proliferated throughout the first week postinjury and accumulated along lesion borders, especially within gray matter. By 3 days postinjury (dpi), new OLs were detected throughout the cross‐sections; between 4 and 7 dpi, however, oligogenesis was restricted to lesion borders. New OLs derived from cells proliferating during 1–7 dpi increased dramatically by 14 dpi; most were located along lesion borders and in spared gray matter. Oligogenesis continued along lesion borders during the second week postinjury. Overall OL numbers were reduced at 3 dpi in spared tissue, but rebounded to normal levels by 14 dpi. Surprisingly, lesion borders maintained normal OL numbers at 3 dpi, which then rose to exceed preinjury levels at 7 and 14 dpi. These results indicate that oligogenesis is protracted after SCI and leads to increased OL numbers. Most new OLs are formed in regions of greatest NG2 cell proliferation. Thus, the adult spinal cord spontaneously develops a dynamic gliogenic zone along lesion borders. © 2007 Wiley‐Liss, Inc.
White Count, Ph and Lactate in Ascites in the Diagnosis of Spontaneous Bacterial Peritonitis
Authors: Yang Chaur-Young , Liaw Yun-Fan , Chu Chia-Ming , Sheen I-Shyan
Published: March 2007

In order to evaluate the diagnostic accuracy of ascitic pH and lactate for early confirmation of spontaneous bacterial peritonitis (SBP), 109 consecutive patients with ascites were studied. The mean ascitic leukocyte [white blood cell (WBC)] and polymorphonuclear cell (PMN) counts, pH and lactate levels in 42 patients with sterile “normal” ascites were 124 ± 157 per mm3, 41 ± 77 per mm3, 7.502 ± 0.097 and 11.1 ± 7.9 mg per dl, respectively, Mean ascitic WBC and PMN counts were significantly increased in 10 patients with SBP (10,452 ± 8,091 and 9,522 ± 7,470 per mm3), in 10 patients with bloody ascites (2,591 ± 4,284 and 1,057 ± 1,494 per mm3) and in 11 patients with cytology positive malignant ascites (1,529 ± 2,071 and 868 ± 1,601 per mm3) (p < 0.001). Mean ascitic pH was significantly reduced in SBP (7.335 ± 0.048), in bloody ascites (7.384 ± 0.037) and in cytology positive malignant ascites (7.355 ± 0.167) (p < 0.001). Mean ascitic lactate was also significantly elevated in these three groups of patients (36.8 ± 17.0, 42.8 ± 35.8 and 24.0 ± 17.5 mg per dl, respectively; p < 0.001) as well as in patients with bacteremia (51.6 ± 78.0 mg per dl, p < 0.005). However, ascitic pH less than 7.31, ascitic lactate greater than 33 mg per dl were observed only in three of the patients with SBP. It is concluded that, after excluding bloody ascites, malignancy and systemic lactic acidosis, the diagnosis of SBP could be made with high sensitivity, specificity and predictive value if ascitic fluid studies fulfill any two of the following three criteria: (i) WBC greater than 1,000 per mm3or PMN greater than 500 per mm3; (ii) pH less than 7.40, and (iii) lactate greater than 25 mg per dl.
Oral, Nonabsorbable Antibiotics Prevent Infection in Cirrhotics With Gastrointestinal Hemorrhage
Authors: Rimola Antoni , Bory Felipe , Teres Josep , Perez-Ayuso Rosa M. , Arroyo Vicente , Rodes Joan
Published: March 2007

To investigate if oral, nonabsorbable antibiotics prevent bacterial infections in cirrhotics with gastrointestinal hemorrhage, 140 consecutive patients were randomly allocated into two groups: 68 patients (Group I) were given oral, non absorbable antibiotics (gentamicin + vancomycin + nystatin or neomycin + colistin + nystatin) from the inclusion into the trial up to 48 hr after cessation of the hemorrhage, or until emergency surgery or death in those cases who continued bleeding; and 72 patients (Group II) did not receive oral, nonabsorbable antibiotics. Both groups were similar in relation to clinical and laboratory data and characteristics of the hemorrhage. The incidence of infection was significantly lower in Group I than in Group II (11 patients in Group I and 25 in Group II developed proved infections; p < 0.025). This difference was due to the fact that spontaneous bacteremia and peritonitis and urinary tract infection caused by enteric bacteria occurred almost exclusively in Group II. Two patients of Group I and 10 of Group II developed spontaneous bacteremia and/or peritonitis caused by enteric bacteria (p < 0.025). These results indicate that prophylactic administration of oral, nonabsorbable antibiotics markedly reduces the incidence of infections caused by enteric bacteria in cirrhotic patients with gastrointestinal hemorrhage.
Prognostic Value of Serum Fibronectin Concentration in Alcoholic Cirrhotic Patients
Authors: Naveau Sylvie , Poynard Thierry , Abella Annie , Pignon Jean-Pierre , Poitrine Alain , Agostini Hélène , Zourabichvili Othar , Chaput Jean-Claude
Published: March 2007

The aim of this study was to assess prospectively the prognostic value of serum fibronectin in 114 alcoholic cirrhotic patients and to compare serum fibronectin with other prognostic variables. The Cox model and log–rank test were used to compare survival rates at 1 year. Considered alone, serum fibronectin, age, serum albumin, total serum bilirubin, γ–glutamyl transpeptidase, prothrombin time, presence of encephalopathy and ascites were associated with survival to 1 year. The estimated survival rate at the end of 1 year was, for patients with serum fibronectin >165 mg per liter: 84 ± 5%, and for patients with serum fibronectin ≤165 mg per liter: 53 ± 7% (p < 0.001). With the step–wise multidimensional analysis using the Cox model to assess the combined effect of several prognostic variables, serum fibronectin was the first variable selected followed by age, encephalopathy and serum albumin which entered the model by virtue of their independent prognostic value. Multivariate regression and partial correlation analysis showed that fibronectin was independently correlated with serum albumin, γ–glutamyl transpeptidase and total serum bilirubin explaining that the prognostic value of albumin diminished and that the prognostic value of total serum bilirubin and γ–glutamyl transpeptidase disappeared when combined with serum fibronectin.
Early disturbance of calcium translocation across the plasma membrane in toxic liver injury
Authors: Lauterburg Bernhard H.
Published: March 2007

An increased influx and/or a decreased extrusion of calcium across the plasma membrane resulting in an increase in cytosolic-free calcium could play an important role in the initiation of irreversible cell injury. Therefore, the translocation of calcium across the plasma membrane was probed in the perfused rat liver using multiple indicator dilution methodology. The sucrose space corresponding to the extracellular space amounted to 0.35 ± 0.13 ml per gm liver, and the water space corresponding to the extra- and intracellular spaces was 0.97 ± 0.08 ml per gm. The calcium space was always slightly larger (0.42 ± 0.10 ml per gm) than the sucrose space. The calcium space further increased during perfusion with the calcium ionophore A 23187, whereas the sucrose space remained unchanged. Two hours after administration to intact rats of acetaminophen (2 gm per kg) and carbon tetrachloride (2 ml per kg), respectively, the calcium space had increased markedly relative to the sucrose space and relative to the water space, indicating an increased accessibility of the cells to extracellular calcium. Similarly, reperfusion of livers after 90 min of ischemia was associated with an increase in calcium space relative to the sucrose and water spaces. These studies indicate that, in three models of acute liver injury, the net influx of calcium across the plasma membrane is increased early in the evolution of the injury before irreversible damage occurs.
Changes in the cytokeratin intermediate filament cytoskeleton associated with mallory body formation in mouse and human liver
Authors: Katsuma Y. , Swierenga S. H. H. , Khettry U. , Marceau N. , French S. W.
Published: March 2007

Mouse and human extracted liver tissue were examined by indirect immunofluorescent staining and transmission electron microscopy in order to study the alteration of cytokeratin intermediate filaments associated with Mallory body formation. Frozen sections of griseofulvin-fed mouse liver and human liver of primary biliary cirrhosis and primary sclerosing cholangitis were extracted by Triton X-100 and nuclease. Indirect immunofluorescent staining was performed by using anticow hoof keratin antibody for mouse liver and anti-human epidermal keratin antibody (AE1 and AE3) for human liver. Transmission electron microscopy was also performed on extracted and critical point-dried samples. The griseofulvin-fed mouse hepatoma cells showed four different types of altered staining pattern based on the indirect immunofluorescent staining of the cytoplasm and Mallory bodies: Type I—cytoplasm(+), Mallory body(−); Type II—cytoplasm(+), Mallory body(+); Type III—cytoplasm(−), Mallory body(+), and Type IV—cytoplasm(−), Mallory body(−). Types I and III were predominant, however, some hepatoma cells which contain Mallory bodies revealed bright cytoplasmic staining (Type II). The nuclear rims were strongly stained. In human liver, AE1 stained Mallory bodies and the bile duct epithelium intensely, but did not stain normal hepatocytes. AE3 mainly stained Mallory bodies and normal hepatocytes, but also stained bile duct epithelium weakly. Indirect immunofluorescent staining for human liver showed the same staining patterns as found in mouse liver, except that Type IV was not observed. Although many hepatocytes which contained Mallory bodies did not react with either of these two antibodies (Type III), some of the hepatocytes were stained, not only with AE3, but also with AE1 (Type II). Transmission electron microscopy revealed that Mallory bodies were often surrounded by numerous intermediate filaments, which is equivalent to the Type II pattern in indirect immunofluorescent staining. This was true of mouse liver frozen sections and primary cultures, as well as human liver studied. The results clearly show that cells associated with Mallory bodies show changes in the expression of cytokeratins as well as rearrangement of intermediate filaments within the cell. Hepatocytes forming Mallory bodies often contain a variable density of intermediate filaments which fail to stain with cytokeratin antibodies, indicating that the antigenic determinants of the intermediate filaments were lost or masked.
Increase in the number of fenestrae in mouse endothelial liver cells by altering the cytoskeleton with cytochalasin B
Authors: Steffan Anne-Marie , Gendrault Jean-Louis , Kirn André
Published: March 2007

Endothelial cells of the hepatic sinusoid isolated from mice livers and maintained in culture display typical fenestrae grouped in sieve plates. Treatment with cytochalasin B led to no significant change in the mean diameter of the fenestrae but to an increase in their number and in the porosity of the cells (percentage of the cellular surface opened by the fenestrae) which attained up to 300% of that of the controls. Scanning electron microscopic observations of Triton-extracted cells revealed that these modifications were related to an alteration of the cytoskeleton. The effect of cytochalasin B could be reversed; 3 hr after removal of the drug, the cells recovered their original aspect with sieve plates scattered over their surface.

These observations demonstrate that endothelial fenestrae are inducible structures and that the cytoskeleton seems to be involved in their formation.
Bile canalicular morphometry in arteriohepatic dysplasia
Authors: Witzleben C. L. , Finegold Milton , Piccoli David A. , Treem William R.
Published: March 2007

The diagnosis of arteriohepatic dysplasia may be difficult, particularly in very young patients with no family history, and the pathogenesis of the disorder remains obscure. It has been reported that the typical ultrastructural changes of cholestasis are scant in this condition and proposed that there is a failure of the hepatocytes to secrete bile into the canaliculi. In an attempt to expand on these observations and to test the value of ultrastructure as a differential diagnostic test for this condition, we chose two parameters felt to be associated with cholestasis that could be reliably and relatively simply determined by ultrastructural morphometry: canalicular dilatation and loss of canalicular microvilli. The values for these parameters were compared in arteriohepatic dysplasia with those in other infantile cholestatic conditions and with those in noncholestatic controls. The results of these morphometric studies corroborated the previous observation that canalicular dilatation in arteriohepatic dysplasia is minimal. There was, however, only a marginal difference in canalicular area between patients with arteriohepatic dysplasia and those with extrahepatic biliary atresia. There was significant overlap of values for canalicular area among all groups. Surprisingly, the studies showed no real loss of canalicular microvilli in any of the cholestatic conditions. The findings suggest that, at least for these two parameters, caution should be exercised in using qualitative electron microscopic evaluation as a diagnostic test for arteriohepatic dysplasia.
Electron microscopic evaluation of brain edema in rabbits with galactosamine-induced fulminant hepatic failure: Ultrastructure and integrity of the blood-brain barrier
Authors: Traber Peter G. , Dal Canto Mauro , Ganger Daniel R. , Blei Andres T.
Published: March 2007

Brain edema is a major complication of fulminant hepatic failure and is responsible for death in a large percentage of patients. We previously demonstrated the progressive accumulation of water in grey matter areas of the brain in the rabbit with galactosamine-induced fulminant hepatic failure. We now report the electron microscopic morphology of the brain in the same model of acute hepatic failure following the intravenous injection of horseradish peroxidase, an intravascular tracer which forms an electron-dense reaction product. Rabbits with both mild and severe encephalopathy had normal blood pressures and blood gases at the time of study. Fixation of brain tissue was obtained by whole-body perfusion. Marked swelling of the cytoplasm, perineuronal and perivascular processes of astrocytes were noted in cortical gray, but not white, matter areas; the other cellular components of the brain had normal morphology. Capillary endothelial cells were normal, and there was no evidence of horseradish peroxidase in endothelial cell vesicles, basement membranes or the brain parenchyma, suggesting that the blood-brain barrier was impermeable to large molecules. Histologic evidence of brain edema is seen in this model, with swelling of astrocytes as the primary manifestation of the accumulation of water. Damage to astrocytes or inhibition of their function may contribute to the pathogenesis of hepatic encephalopathy in this model.
Lactitol vs. lactulose in the treatment of acute hepatic encephalopathy in cirrhotic patients: A double-blind, randomized trial
Authors: Morgan Marsha Y. , Hawley Katherine E.
Published: March 2007

Lactitol (β-galactosido-sorbitol) is a nonabsorbable disaccharide available as a powder which, in open comparison, is as effective as lactulose in the treatment of chronic hepatic encephalopathy, but is better tolerated. Twenty-five cirrhotic patients experiencing 28 episodes of acute hepatic encephalopathy were randomized blindly to treatment with either lactitol (n = 15) or lactulose (n = 13). The sugars were dispensed in solutions identical in appearance, taste and pH and of similar osmolarity, which contained either 66.7 gm per 100 ml lactitol or 66.7 ml (44.5 gm) per 100 ml lactulose syrup. The initial dose of 0.75 ml per kg was adjusted to produce two semisoft stools per day. Patients were assessed every 12 hr for 5 days. There were no significant differences in sex ratio, age, body weight, clinical status, duration and extent of coma, etiology of liver disease or of heptic encephalopathy between the two groups of patients on entry to the trial. An adequate catharsis was obtained with an equivalent mean (± 1 S.D.) daily dose of 26 ± 5 gm lactitol or 31 ± 7 ml (21 ± 5 gm) lactulose syrup. During the trial, significant improvements occurred in clinical status and psychometric performance and in the electroencephalogram mean cycle frequencies in the majority of patients in both groups. At the end of the trial, 67% of the patients in the lactitol group and 69% of the lactulose group were clinically normal. However, patients treated with lactitol responded significantly more quickly than patients treated with lactulose. Thus, at 24, 36, 48 and 72 hr, significantly greater mean percentage improvements were seen in PSE Indices in patients receiving lactitol than in patients receiving lactulose. Both sugars are effective in the treatment of acute hepatic encephalopathy in cirrhotic patients, but patients treated with lactitol respond significantly more quickly. Lactitol may be the treatment of choice for this condition.
Immunogenetic studies of autoimmune chronic active hepatitis: HLA, immunoglobulin allotypes and autoantibodies
Authors: Krawitt Edward L. , Kilby Alan E. , Albertini Richard J. , Schanfield Moses S. , Chastenay Bettejayne F. , Harper Phillip C. , Mickey Ruth M. , McAuliffe Timothy L.
Published: March 2007

The strategy of assigning a surrogate phenotype, defined as the presence of antinuclear and/or antismooth muscle antibodies to disease-free first degree relatives of index cases was used to search for a postulated disease susceptibility gene in autoimmune chronic active hepatitis. In addition to determining circulating autoantibody status, 10 patients, 51 first-degree relatives and 6 spouses of index chronic active hepatitis patients, each ascertained by the single patient, were genotyped for HLA (A, B and DR loci) and immunoglobulin allotype (Glm, G2m, G3m and A2m loci) haplotypes. Among the 10 chronic active hepatitis patients, 6 had HLA haplotypes B8 and DR3, and 3 of these patients had, in addition, the immunoglobulin allotype haplotype Gm a, x;g. Circulating autoantibodies defining the surrogate phenotype was found in 39% of the first-degree relatives. However, segregation analysis offered no support for either single autosomal dominant or recessive inheritance for the autoantibody-positive phenotype. Linkage between the postulated disease susceptibility locus and either the HLA (Chromosome 6) or immunoglobulin (Chromosome 14) locus was excluded by several analyses. Furthermore, logistic regression indicated that neither immunogenetic marker was statistically associated with autoantibody positively in these families. Therefore, despite the occurrence of autoantibody positivity in first-degree relatives of autoimmune chronic active hepatitis patients, we found no evidence that this trait has a simple genetic basis, or that it is an alternative manifestation of a postulated disease susceptibility gene for chronic active hepatitis.
Elevated HLA class i antigen expression on peripheral blood mononuclear cells of HBsAg carriers with coexistent human immunodeficiency virus infection
Authors: Paul Robert G. , Roodman Stanford T. , Paul Deborah A. , Perrillo Robert P.
Published: March 2007

The density of HLA Class I antigen on peripheral blood mononuclear cells was evaluated by flow cytometry in the following groups of patients: 41 HBsAg carriers; 12 individuals with chronic non-A, non-B hepatitis, and 4 with acute hepatitis B. Fourteen of the carriers were positive for antibody to human immunodeficiency virus, and all were negative for antibody to delta agent. Elevated levels of Class I antigen were observed in only 19% of patients with chronic hepatitis B virus infection alone. In contrast, 86% of HBsAg carriers with coexistent human immunodeficiency virus infection demonstrated increased expression. These data suggest that HBsAg carriers are capable of sustaining a systemic interferon response to another chronic viral infection and further supports the hypothesis that a defective interferon response exists in chronic hepatitis B virus infection.
Inhibition of gluconeogenesis by hypoglycin: Alternate interpretations
Authors: Tanaka Kay
Published: March 2007

Treatment of rats with hypoglycaemic doses of hypoglycin has been shown to abolish the relative detritiation of [2-3H, U-14C]glucose [Osmundsen, Billington, Taylor & Sherratt (1978) Biochem. J. 170, 337-342], indicating that both the Cori and the glucose/glucose 6-phosphate cycles were inhibited in vivo. This inhibition was confirmed and, in addition, it was shown that the conversion in vivo of both [14C]lactate and [14C]fructose into glucose was decreased after hypoglycin treatment. These results suggest that hypoglycin poisoning results in the inhibition in vivo of glucose-6-phosphatase activity, which participates in the overall inhibition of gluconeogenesis and hypoglycaemia. Clofibrate feeding apparently protected the rats against the inhibition of the fructose-to-glucose conversion by hypoglycin. However, in isolated hepatocytes prepared from hypoglycin-treated rats, the conversion of [14C]fructose into glucose and the recycling of [2-3H, W-14C]glucose were not different from that in control hepatocytes. This suggests that the inhibition was lost during preparation of the hepatocytes. The direct measurement of glucose-6-phosphatase activity showed that it was inhibited when measured in concentrated, but not dilute, homogenates prepared from hypoglycin-treated rats.